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Article

Detection of Extended-Spectrum β-Lactamase (ESBL) E. coli at Different Processing Stages in Three Broiler Abattoirs

by
Nina Langkabel
1,2,*,
Janine Burgard
1,
Sabrina Freter
1,
Reinhard Fries
1,
Diana Meemken
1,2,* and
Lüppo Ellerbroek
3
1
Working Group Meat Hygiene, Institute of Food Safety and Food Hygiene, School of Veterinary Medicine, Freie Universität Berlin, 14163 Berlin, Germany
2
Veterinary Centre for Resistance Research, Freie Universität Berlin, 14163 Berlin, Germany
3
Federal Ministry of Food and Agriculture, 10117 Berlin, Germany
*
Authors to whom correspondence should be addressed.
Microorganisms 2023, 11(10), 2541; https://doi.org/10.3390/microorganisms11102541
Submission received: 31 August 2023 / Revised: 28 September 2023 / Accepted: 10 October 2023 / Published: 12 October 2023
(This article belongs to the Special Issue Detection and Identification of Pathogenic Bacteria and Viruses)
Browse Figure
Versions Notes

Abstract

:
The European Food Safety Authority (EFSA) identified extended-spectrum β-lactamase/AmpC β-lactamase (ESBL/AmpC)-producing E. coli as one of the main priority hazards for poultry. Different studies detected ESBL-producing E. coli at broiler fattening farms and in abattoirs, concluding that poultry meat is a potential source of human infection. Broiler breast skin samples taken in three abattoirs with different scalding techniques were examined for ESBL-producing Escherichia (E.) coli and their phylogenetic groups. A total of 307 ESBL-producing E. coli isolates were found, and the abattoir with conventional immersion scalding with thermal treatment of the water had the lowest incidence. Phylogroups D/E and B1 were mostly detected, while phylogroups C, D, and E were not detected. Phylogroup B2 was detected in low proportions. The phylogroups B2 and D are important as they have been associated with urinary tract infections in humans, but were only detected in low proportions at different processing stages in this study. Since the risk for the consumer of being infected via chicken meat with ESBL-producing E. coli and E. coli of highly pathogenic phylogroups cannot be excluded, good kitchen hygiene is of great importance.

1. Introduction

Escherichia (E.) coli is a member of the Enterobacteriaceae family and lives commensally in the gastrointestinal tract of humans and animals [1,2,3]. These bacteria can spread via fecal shedding to the environment or during meat production onto the processed food. In the framework of meat production, ensuring good slaughter hygiene and avoiding fecal contamination is of great importance [4,5,6]. As a result, the surveillance of Enterobacteriaceae counts on carcasses is regulated for different animal species in the European Union (EU) [7]. In this context, E. coli can act as an indicator for fecal contamination of carcasses and food. Thus, it was suggested that testing for E. coli should be performed in regard to process hygiene controls in broiler abattoirs [8,9,10]. Besides being commensals, some E. coli strains carry virulence factors and can cause severe diseases in humans [1]. As described by Clermont et al. (2000 and 2013) [11,12], classification of E. coli strains via their phylogenetic groups is possible with a polymerase chain reaction (PCR). Currently, the seven groups (A, B1, B2, C, D, E, and F), which are associated with E. coli and the Escherichia clades (I, III, IV, and V) originating from E. coli, are described as phylogenetic groups [11,12]. Phylogroups A and B1 are found mainly in commensal E. coli strains, whereas phylogroups B2 and D are associated with severe infections in humans [13,14]. Additionally, resistance against antimicrobials is of importance, since extended-spectrum β-lactamase/AmpC β-lactamase (ESBL/AmpC)-producing E. coli can be found in humans, food producing animals, and food products, and were identified as one of the main hazards to be covered in meat inspection of poultry [8,15,16,17]. Depending on the genes present, different ESBL types are distinguished, with TEM, SHV, and CTX-M being the most frequently reported representatives [15,17,18,19,20].
Poultry meat is the most commonly consumed meat worldwide [21]. Today’s slaughtering and processing of broilers for food production is a highly automated process with high hygienic standards. Despite that, foodborne infections associated with poultry meat consumption are frequently reported, mainly campylobacteriosis and salmonellosis [16]. Each processing step can have an influence on the bacterial load that broilers carry on their feathers when entering the abattoir [22,23,24]. While some process steps reduce the bacterial load of carcasses, others can lead to an increase [5,22,23,24,25,26,27]. One important processing stage, which can be seen as a combination stage, is the steps of scalding and plucking. Scalding and plucking are necessary to remove the feathers from the carcasses, which is of great importance because feces adhering to skin and feathers may lead to (cross-)contamination of the carcasses and meat during production [28]. Both processing steps were identified as having an influence on the bacterial load, but studies are contradictory, meaning that a decrease but also an increase was seen, depending on the abattoir investigated [5,23,29,30,31]. Despite all poultry line automation and current technical solutions, it remains impossible to produce poultry meat without bacterial contamination. Besides Campylobacter and Salmonella, the European Food Safety Authority (EFSA) identified ESBL/AmpC-producing E. coli as one of the main priority hazards for poultry meat [8], and the occurrence in broiler meat in the EU remained at high levels in 2020 [16]. However, decreasing trends of ESBL/AmpC-producing E. coli in broilers and turkeys were reported [32] in recent years. This is supported by different studies that detected ESBL-producing E. coli at broiler fattening farms, in abattoirs, and in retail meat, concluding that poultry meat is a potential source of human infection with ESBL/AmpC-producing Enterobacteriaceae [23,26,33,34,35,36,37,38,39,40,41]. Since each flock has its own bacterial spectrum and load, and each abattoir has to be seen as unique, individual hygiene control programs to reduce the bacterial loads of the carcasses through the production process in place need to be applied [8,26,42].
We conducted a study at three commercial broiler abattoirs that used different scalding techniques to investigate the occurrence of ESBL-producing E. coli on broiler breast skin samples at different processing steps from the beginning to end of the slaughter line.

2. Materials and Methods

2.1. Sampling

Between May 2016 and February 2018, breast skin samples of broilers were taken at three commercial broiler abattoirs in Germany and in The Netherlands, with slaughter capacities between 10,000 and 13,500 birds per hour. The slaughter lines were constructed in similar ways and operated with scalding temperatures between 51 °C and 55 °C. The installed scalding technique differed in the three abattoirs. Abattoir 1 operated a conventional immersion scalder with two scalding tanks. In Abattoir 2, an immersion scalder with three scalding tanks, where the scalding water was reused and underwent a thermal treatment before being reintroduced in the third scalding tank, was installed. The scalding principle of the immersion scalders is based on convection, and the carcasses are pulled through the scalding water. The so-called AeroScalder® (Marel, Boxmeer, The Netherlands) [43] in Abattoir 3 uses hot, humid, saturated air as the scalding medium. The scalding principle of the AeroScalder® is based on condensation, which means that the hot air that is blown between the feathers condenses at the colder surface of the carcasses. The temperature at the carcass surface is similar to the temperatures operating with low scalding temperatures, even though the hot, humid, saturated air is warmed to 57 °C.
Per abattoir, 320 breast skin samples without feathers from carcasses out of 48 flocks were taken at the following 5 sampling positions: (a) before scalding, (b) after scalding, (c) after plucking, (d) directly before chilling, and (e) after chilling. At each sampling position, one abattoir employee removed four carcasses, chosen randomly, successively from the slaughter line and held them head-down for sampling. For breast skin excision, two imaginary lines were located across the carcass, one between the joints where the wings join the body and another below the sternum approximately at the level of a line between the hip joints. On each side of the carcass, the ends of these two lines were then imagined as being connected with each other vertically, along the carcass length. For sampling, sterile stainless-steel forceps, and single-use scalpels (B. Braun Melsungen AG, Melsungen, Germany) were used. The breast skin was lifted slightly with the forceps, and incisions were made carefully along the imaginary lines to aseptically remove all the breast skin on the carcass. Each breast skin sample was placed in a sterile blender bag with lateral filter for volumes up to 400 mL (VWR International GmbH, Darmstadt, Germany) and cooled immediately to 4 °C. All samples were transported at 4 °C to the laboratory at Freie Universität Berlin, Germany, and were stored in a refrigerator that maintained a temperature of around 4 °C until the next morning, when the laboratory work started.

2.2. Bacteriological Examination and Statistical Analysis

Each breast skin sample was weighed before analysis and was blended in a 1:9 ratio with Luria Bertani broth (LB; Carl Roth GmbH & Co., KG, Karlsruhe, Germany) in the blender bag that had been used for sample transportation. Dilution series were created, and 0.05 mL from each dilution were dropped in duplicate on MacConkey No. 3 agar plates (Thermo Fisher Diagnostics GmbH (former Oxoid Deutschland GmbH), Wesel, Germany) + 1 μg/mL cefotaxime (AppliChem, Darmstadt, Germany) and streaked out with the pipette tip. In parallel, the remainder of the blended breast skin sample and LB was used for enrichment via incubation at 37 °C overnight and the next day, streaking it out with a loop on MacConkey No. 3 agar plates (Thermo Fisher Diagnostics GmbH (former Oxoid Deutschland GmbH), Wesel, Germany) + 1 μg/mL cefotaxime (AppliChem, Darmstadt, Germany).
Microbial analyses of ESBL-producing E. coli included an isolation step on MacConkey agar No. 3 + cefotaxime, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) examination, disc diffusion testing, PCR for ESBL genes (blaCTX-M, blaSHV, and blaTEM), and gene sequencing. All ESBL-producing E. coli isolates identified using these described methods underwent an additional PCR test for identification of the phylogenetic groups of E. coli, following Clermont et al. (2013) [12].
As the first step, colony morphology on MacConkey No. 3 agar (Thermo Fisher Diagnostics GmbH (former Oxoid Deutschland GmbH), Wesel, Germany) + 1 μg/mL cefotaxime (AppliChem, Darmstadt, Germany) was described, and suspected ESBL/AmpC E. coli (pink to reddish) colonies were subcultured until pure colonies were obtained.
These pure, suspected ESBL/AmpC E. coli colonies were used for further identification and confirmation with MALDI-TOF MS (MALDI Microflex LT and Biotyper database, Bruker Daltonics, Bremen, Germany). Per each suspected ESBL/AmpC E. coli isolate, two fields on the MALDI-TOF MS target plate were covered with a small amount of colony material and overlayed with 1 μL matrix solution. For preparing 1 mL of the matrix solution, 500 µL acetonitrile (VWR International GmbH, Darmstadt, Germany), 475 µL distilled water (Aqua dest.; VWR International GmbH, Darmstadt, Germany), and 25 µL trifluoroacetic acid (Sigma-Aldrich, Chemie GmbH, Taufkirchen, Germany) were mixed for 2 min before 20 mg of α-cyano-4-hydroxycinnamic acid was added and the solution was mixed again for 3 min. After centrifugation, the supernatant was used as the matrix solution.
For isolates that were confirmed as E. coli with MALDI-TOF MS, antimicrobial susceptibility testing with disc diffusion tests for ESBL was performed according to the CLSI standards [44]. A suspension in 3 mL LB-broth (Carl Roth GmbH & Co., KG, Karlsruhe, Germany) was created per isolate and incubated at 37 °C for 6 to 24 h. From each culture, a suspension equivalent to McFarland standard 0.5 was prepared using a densitometer (Grant Bio DEN-1 McFarland Tube Densitometer, Grant Instruments, Cambridge, UK). The test discs for agar diffusion tests can be found in Table 1.
Additionally, the isolates were tested for the most common ESBL genes, blaCTX-M, blaSHV, and blaTEM, and additionally blaCMY-2, with a real-time PCR protocol [45]. For DNA extraction, isolates were incubated overnight at 37 °C in 3 mL LB-broth (Carl Roth GmbH & Co., KG, Karlsruhe, Germany). From each overnight culture, 1 mL was centrifuged (14,000 rpm, 4 min), and after discarding the supernatant, the resulting pellet was washed in 250 µL 0.1% TE buffer (VWR International GmbH, Darmstadt, Germany). After centrifugation of this solution (14,000 rpm, 4 min) and discarding of the supernatant, the pellet was resuspended in 250 µL 5% Chelex® 100 sodium form solution (Sigma–Aldrich Chemie GmbH, Taufkirchen, Germany) and incubated at 56 °C (shaken at 700 rpm, 1 h), followed by incubation at 95 °C (shaken at 700 rpm, 15 min), and a final centrifugation step (14,000 rpm, 10 min). The resulting DNA extract was stored at 7 °C before analysis. The real-time PCR was performed using the Bio-Rad Real-Time PCR Detection System CFX96 (Bio-Rad Laboratories GmbH, Feldkirchen, Germany). The primers and probes as well as the PCR conditions followed the protocol set by Roschanki et al. (2014) [45]. The PCR-cycles used [45] were as follows:
  • One cycle: denaturation        15 min, 95 °C
  • Thirty cycles:
    o
    Denaturation                       15 s, 95 °C
    o
    Binding                                15 s, 50 °C
    o
    Elongation                           20 s, 70 °C
The real-time PCR results were evaluated using Bio-Rad CFX-ManagerTM 3.1 software (Bio-Rad Laboratories GmbH, Feldkirchen, Germany). All isolates that were CMY-positive were not used for further analyses because they were considered to be AmpC β-lactamase-producing E. coli. All isolates encoding for CTX were considered as ESBL-producing E. coli.
From isolates in which only blaTEM or blaSHV was found, DNA was extracted with GeneJet PCR Purification Kit (Thermo Fisher Scientific Baltics UAB, Vilnius, Lithuania) following the manufacturer’s instructions. DNA purity and concentration was measured with NanoDropTM 2000 (Thermo Fisher, (Thermo Fisher Scientific, Wilmington, MA, USA). After the assessment, pure DNA (200 ng/µL to 100 ng/µL) with primer sequences for blaTEM or blaSHV, as described by Projahn et al. (2017) [46], was sent for gene sequencing to Eurofins Genomics (Eurofins GATC Biotech GmbH, Konstanz, Germany).
In the last step, phylogenetic groups for all ESBL-producing E. coli isolates were identified using the PCR protocol according to Clermont et al. (2013) [12].
For statistical analysis, this study was planned to utilize descriptive analysis of resistance encoding genes at three different abattoirs. The descriptive statistical analyses were carried out using IBM® SPSS® version 28.0.1.0 for Windows and figures were built with Microsoft® Excel® LTSC Professional Plus 2021 version 2108. For testing the association between phylogenetic groups and resistance encoding genes, the Fisher exact test was performed; p-values < 0.05 were regarded as statistically significant.

3. Results

In total, 960 breast skin samples were analyzed, and after the stepwise analysis for ESBL-producing E. coli, 307 isolates were finally confirmed. From some samples, more than one isolate was obtained. For further analysis, only the ESBL-producing E. coli isolates obtained were used.
The frequency of ESBL-producing E. coli detection varied between the three abattoirs and between the different sampling positions. Abattoir 3 with the AeroScalder® showed the highest frequency with 128/307 (41.7%) isolates, followed by Abattoir 1 that used an immersion scalder with 117/307 (38.1%) isolates, and then Abattoir 2 that used an immersion scalder with thermal treatment of the water with the lowest frequency with 62/307 (20.1%) isolates. ESBL-producing E. coli were found at all sampling positions, with higher incidences at the beginning of the slaughter process except for Abattoir 2, where an increase after plucking was seen (Figure 1).
The frequency of the encoding genes in total was the highest for blaCTX-M (69.7%, 214/307), followed by blaTEM-52 (14.9%, 46/307), and blaSHV-12 (15.3%, 47/307). In Abattoir 1, blaCTX-M was the most frequently found encoding gene in all sampling positions. BlaSHV-12 was found in four isolates before scalding, two of them from birds out of one flock. In Abattoir 3, mostly high frequencies of blaCTX-M and blaSHV-12 were found at all sampling positions; however, blaTEM-52 was not found before chilling (Figure 1).
The antimicrobial susceptibility test using agar diffusion was performed on all 307 isolates; however, results were only obtained for 302 isolates because 5 isolates were non-culturable despite our standard laboratory culture and storage practices. Of these 302 isolates, 6 isolates were susceptible to CTX but harbored TEM-52 (1/6) and/or SHV-12 (5/6) encoding genes. These isolates were obtained from all abattoirs, with three isolates from one flock at Abattoir 2. In total, 28 isolates were resistant to 2 of the tested antibiotics (FOX-CTX: 1/28 (3.6%); CAZ-CTX: 27/28 (96.4%)). The isolates that were resistant to CAZ and CTX were found on different sampling days at all three abattoirs (11 at Abattoir 1, 1 at Abattoir 2, and 15 at Abattoir 3). At Abattoir 1, three isolates were found on an early sampling day and belonged to the same flock, and another seven isolates from a later sampling day were also from just one flock. At Abattoir 3, two isolates from one flock were found on one of the sampling days. On a later sampling day, eleven isolates were found, of which six belonged to the first flock sampled that day and five to the second flock sampled (see Supplementary Materials. Overall, four isolates were resistant to three of the tested antibiotics (FOX-CAZ-CTX: 3/4 (75%); CAZ-CTX-MRP: 1/4 (25%)). Two of the three isolates that were resistant to FOX, CAZ, and CTX were from the same flock, sampled at Abattoir 2 after chilling. The other two isolates with threefold antibiotic resistance were found before scalding at Abattoir 1 and Abattoir 3, respectively (see Supplementary Materials).
Various E. coli phylogroups were found at the three abattoirs. No isolate belonged to phylogroups C, D, E, or E/E. clades. At Abattoir 1 (using conventional immersion scalding), predominant phylogroups were phylogroups D/E (76/117) and A/C (28/117). In total, just two isolates at the sampling position before scalding and one isolate after chilling belonged to phylogroup B2 (Table 2). At Abattoir 2 (using conventional immersion scalding with thermal treatment of the scalding water), most isolates belonged to E. coli phylogroup B1 (38/63), followed by phylogroup B2 (14/63). The isolates from phylogroup B2 were found after scalding (1), after plucking (8), before chilling (4), and after chilling (1). In addition to the abovementioned undetected phylogroups, phylogroup F was not found at Abattoir 2 (Table 2). The most frequently found phylogroup at Abattoir 3 (using the AeroScalder®) was phylogroup D/E (61/128), followed by phylogroups B1 (36/128) and A/C (25/128). Three isolates belonged to phylogroup B2; two were found before scalding and one after plucking. After chilling, phylogroup B2 was not found. Phylogroups A and F were not found at Abattoir 3 in addition to the abovementioned undetected phylogroups (Table 2).
The resistance profiles of the 20 phylogroup B2 isolates are presented in Table 3. All isolates were meropenem resistant. One isolate at Abattoir 1 before scalding was one of the CTX susceptible isolates. One of the 20 isolates was resistant to two antibiotics (CAZ-CTX) and was found after plucking at Abattoir 2. At Abattoir 3, one of the phylogroup B2 isolates after chilling was resistant to three of the tested antibiotics (FOX-CAZ-CTX). All other isolates were resistant to cefotaxime (CTX) but susceptible to or intermediate to the other three antibiotics tested (Table 3).
Statistical comparison of the associations between phylogroups and resistance encoding genes showed that phylogroup B1 and blaTEM-52 (p < 0.001) and that phylogroup A/C and blaSHV-12 (p < 0.005) had a more frequent statistically significant association with each other. There was no statistically significant association between blaCTX-M and any of the phylogroups found. Phylogroup B2 was also not significantly associated with any of the resistance encoding genes.

4. Discussion

In total, 307 ESBL-producing E. coli isolates were found in 960 broiler breast skin samples taken in the 3 studied abattoirs. As in previous investigations [15,47,48], blaCTX-M was the main gene encoding for antimicrobial resistance found in this study. The occurrence of the antimicrobial resistance genes differed along the slaughter line among the three abattoirs. This finding supports the conclusions of previous studies—that each abattoir is unique regarding the distribution and occurrence of bacteria, and that the microbial loads are influenced by the flock and the abattoir itself [8,27,42,49].
Comparing the three abattoirs, it can be seen that in Abattoir 2, using a conventional immersion scalding tank where the scalding water underwent a thermal treatment before being reintroduced to the scalding tank, the lowest numbers of ESBL-producing E. coli isolates were found, both overall and after scalding. In Abattoir 3, operating the AeroScalder®, which uses hot, humid, saturated air as the scalding medium, the highest numbers of ESBL-producing E. coli were found after scalding. This finding could be explained by the fact that a washing effect, as in the other abattoirs using immersion scalders, was missing. However, after plucking, the numbers of ESBL-producing E. coli were reduced to a lower incidence than was found in Abattoirs 1 and 2. At the end of the slaughter line before chilling, similar numbers of ESBL-producing E. coli isolates were found in all three abattoirs. After chilling in Abattoir 2, the lowest number of ESBL-producing E. coli was found (among the three abattoirs). We could not identify a single production step as having the main influence on reducing ESBL-producing E. coli in the abattoirs studied. Since ESBL-producing E. coli were found after chilling in all three abattoirs, a risk of transmission to the consumer via chicken products on the market must be assumed. Other studies showed frequent findings of ESBL-producing E. coli in broiler abattoirs, including findings in abattoir workers, and proved that this risk exists [16,26,50,51,52].
In Abattoir 2, compared with the other abattoirs, the numbers of ESBL-producing E. coli were the lowest, specifically from the beginning of production and onwards. Therefore, it seems likely that the status of the incoming flock is of great importance, as incoming flocks carrying ESBL-producing E. coli could lead to these microorganisms being distributed through the abattoir. Similar findings were reported from different studies investigating the occurrence of ESBL-producing E. coli in German broiler fattening farms and the surrounding environment [35,36,53,54].
A great variety of phylogroups was seen; however, of the phylogroups known to be associated with severe human diseases, such as urinary tract infections or meningitis [55,56,57], only phylogroup B2 was found, as well as in low numbers compared to the phylogroups known to be linked to apathogenic E. coli strains [13]. Interestingly, the highly virulent phylogroup B2 was found in the highest numbers (especially after plucking), in Abattoir 2, in which the lowest numbers of ESBL-producing E. coli were detected. Thus, it can be assumed that in that unique case, cross-contamination from the plucking fingers was apparent, meaning that the flocks slaughtered before the flocks sampled harbored E. coli phylogroup B2, which were then transferred to the carcasses sampled during plucking. Persistence of E. coli in abattoirs [52] can be a source of contamination during processing.
Regarding the phenotypic resistance profiles, it can be seen that different resistance profiles were found on different sampling days and at different sampling positions. Since we sometimes found the same resistance profiles on the same sampling day, and often in samples belonging to one flock, it is possible that the birds themselves were carriers of E. coli with the respective resistance profiles or that transmission occurred between the birds during slaughter. The detection of E. coli with the same resistance profile in two consecutive flocks sampled on one day could also be explained by transmission from the first to the latter slaughtered flock. Since we did not sample the plucking fingers before our sampling, we can only assume this possibility, but Pacholewicz et al. (2015) [26] showed decreases in ESBL-producing E. coli after defeathering. In contrast, other authors reported increases of microbial loads after plucking [58,59,60]; therefore, the risk of cross-contamination during processing must be considered. However, since we did not find E. coli with the same resistance profile in the following sampling days at sampling positions after scalding, it seems that the incoming birds were more likely a source of the ESBL-producing E. coli rather than an accumulation of these bacteria in the abattoir. Therefore, it can be assumed that the cleaning and disinfection procedures in the abattoirs were a control method against the accumulation of EBSL-producing E. coli. Nonetheless, it must be taken into consideration that some of our examined breast skin samples harbored ESBL-producing E. coli; thus, the hygiene during the cutting of poultry carcasses is important because, during that process, bacteria can transfer from the outer parts of the carcasses to the meat and processed products. Overall, the pathogenic phylogroup B2 was only found twice after chilling in different abattoirs; however, in one case, it showed a threefold antibiotic resistance, as shown before in poultry meat [61]. Therefore, it seems that broilers probably have a low prevalence of phylogroup B2, as was also shown in a study by Reich et al. (2013) [33]. Nevertheless, highly virulent, and highly resistant ESBL-producing E. coli can still occur on the carcasses after chilling (like in this study). On the other hand, phylogroups representing commensal E. coli were mainly found by us, and it can be concluded that the risk of severe infections seems to be low. However, the fact that all isolates examined were ESBL-producing E. coli with various resistance profiles must be considered in the context of chicken meat safety, as it shows that transmission to humans via this food is possible, even if the risk appears to be low from our point of view.

5. Conclusions

In the three abattoirs investigated, we determined that the different scalding techniques in combination with the different incoming flocks lead to the reductions in different bacteria. ESBL-producing E. coli and human pathogenic E. coli were found at different processing steps along the slaughter lines and were able to contaminate broiler carcasses after scalding and even after chilling.
The risk of transmission, via chicken meat consumption, of antimicrobial resistant E. coli with phylogenic group profiles that can cause serious illness in humans cannot be excluded. Therefore, good hygiene during cutting and adherence to good kitchen hygiene guidelines, which are mainly used to prevent Campylobacter and Salmonella infections via raw chicken meat, should also be considered important for preventing infections with ESBL-producing E. coli via chicken meat. In addition, further research should focus on the individual microbiota of slaughterhouse operations and how the component bacteria are affected by processing, management, and daily cleaning and disinfection procedures.

Supplementary Materials

The following supporting information can be downloaded at: https://www.mdpi.com/article/10.3390/microorganisms11102541/s1. Table S1: Results ESBL positive isolates.

Author Contributions

Conceptualization, R.F., L.E. and N.L.; methodology, L.E. and N.L.; software, not applicable; validation, not applicable; formal analysis, J.B. and N.L.; investigation, S.F. and J.B.; resources, not applicable; data curation, S.F., J.B. and N.L.; writing—original draft preparation, N.L.; writing—review and editing, D.M., S.F., J.B., R.F., L.E. and N.L.; visualization, J.B. and N.L.; supervision, L.E., D.M. and N.L.; project administration, N.L.; funding acquisition, R.F. All authors have read and agreed to the published version of the manuscript.

Funding

This study was conducted in the framework of the joint research project “EsRAM”. This project was supported by funds of the Federal Ministry of Food and Agriculture (BMEL) based on a decision of the Parliament of the Federal Republic of Germany via the Federal Office for Agriculture and Food (BLE) under the innovation support program; grant ID: 2817701014.

Data Availability Statement

The data presented in this study are available upon request from the corresponding author. Data that can identify the abattoirs are not publicly available due to privacy concerns.

Acknowledgments

The authors acknowledge the support of the broiler abattoirs and their assistance in sampling the carcasses. We thank Uwe Rösler, Institute for Animal Hygiene and Environmental Health, School of Veterinary Medicine, Freie Universität Berlin, for coordinating the joint research project “EsRAM” and for the use of the MALDI-TOF at his laboratory. We thank Thomas Alter, Institute of Food Safety and Food Hygiene, School of Veterinary Medicine, Freie Universität Berlin, for his gracious help with laboratory methods and administrative issues. We thank Roswitha Merle for her help with statistical analysis.

Conflicts of Interest

The authors declare no conflict of interest.

References

  1. Suerbaum, S.; Bockemühl, J.; Karch, H. Enterobakterien. In Medizinische Mikrobiologie und Infektiologie; Suerbaum, S., Hahn, H., Burchard, G.-D., Kaufmann, S.H.E., Schulz, T.F., Eds.; Springer: Berlin/Heidelberg, Germany, 2012; pp. 229–258. [Google Scholar]
  2. Bockemühl, J. Enterobacteriaceae. In Mikrobiologische Diagnostik; Burkhardt, F., Bauernfeind, A., Eds.; Thieme: Stuttgart, Germany, 1992; pp. 119–152. [Google Scholar]
  3. Holt, J.G.; Krieg, N.R.; Sneath, P.H.A.; Staley, J.T.; Williams, S.T. Group 5: Facultative anaerobic Gram-negative rods—Subgroup 1: Family Enterocacteriaceae. In Bergey’s Manual of Determinative Bacteriology, 9th ed.; Holt, J.G., Krieg, N.R., Sneath, P.H.A., Staley, J.T., Williams, S.T., Eds.; Lippincott Williams & Wilkins: Baltmore, MD, USA, 1994; pp. 175–190. [Google Scholar]
  4. Mead, G. Microbial hazards in production and processing. In Poultry Meat Processing and Quality; Mead, G.C., Ed.; Woodhead Publishing Limited: Cambridge, UK, 2004; pp. 232–257. [Google Scholar]
  5. Zweifel, C.; Althaus, D.; Stephan, R. Effects of slaughter operations on the microbiological contamination of broiler carcasses in three abattoirs. Food Control 2015, 51, 37–42. [Google Scholar] [CrossRef]
  6. European Commission. Regulation (EC) No 853/2004 of the European Parliament and of the Council of 29 April 2004 Laying down Specific Hygiene Rules for Food of Animal Origin. Last Consolidated Version: 15.02.2023. 2004. Available online: http://data.europa.eu/eli/reg/2004/853/oj (accessed on 25 August 2023).
  7. European Commission. Regulation (EC) No 2073/2005 of 15 November 2005 on Microbiological Criteria for Foodstuff, Last Consolidated Version: 08.03.2020.; 2005. Available online: http://data.europa.eu/eli/reg/2005/2073/oj (accessed on 25 August 2023).
  8. EFSA. Scientific Opinion on the public health hazards to be covered by inspection of meat (poultry). EFSA J. 2012, 10, 2741. [Google Scholar] [CrossRef]
  9. Ghafir, Y.; China, B.; Dierick, K.; De Zutter, L.; Daube, G. Hygiene indicator microorganisms for selected pathogens on beef, pork, and poultry meats in Belgium. J. Food Prot. 2008, 71, 35–45. [Google Scholar] [CrossRef] [PubMed]
  10. Altekruse, S.F.; Berrang, M.E.; Marks, H.; Patel, B.; Shaw, W.K., Jr.; Saini, P.; Bennett, P.A.; Bailey, J.S. Enumeration of Escherichia coli cells on chicken carcasses as a potential measure of microbial process control in a random selection of slaughter establishments in the United States. Appl. Environ. Microbiol. 2009, 75, 3522–3527. [Google Scholar] [CrossRef] [PubMed]
  11. Clermont, O.; Bonacorsi, S.; Bingen, E. Rapid and simple determination of the Escherichia coli phylogenetic group. Appl. Environ. Microbiol. 2000, 66, 4555–4558. [Google Scholar] [CrossRef] [PubMed]
  12. Clermont, O.; Christenson, J.K.; Denamur, E.; Gordon, D.M. The Clermont Escherichia coli phylo-typing method revisited: Improvement of specificity and detection of new phylo-groups. Environ. Microbiol. Rep. 2013, 5, 58–65. [Google Scholar] [CrossRef] [PubMed]
  13. Picard, B.; Garcia, J.S.; Gouriou, S.; Duriez, P.; Brahimi, N.; Bingen, E.; Elion, J.; Denamur, E. The link between phylogeny and virulence in Escherichia coli extraintestinal infection. Infect. Immun. 1999, 67, 546–553. [Google Scholar] [CrossRef]
  14. Bingen, E.; Picard, B.; Brahimi, N.; Mathy, S.; Desjardins, P.; Elion, J.; Denamur, E. Phylogenetic analysis of Escherichia coli strains causing neonatal meningitis suggests horizontal gene transfer from a predominant pool of highly virulent B2 group strains. J. Infect. Dis. 1998, 177, 642–650. [Google Scholar] [CrossRef] [PubMed]
  15. EFSA. Scientific Opinion on the public health risks of bacterial strains producing extended-spectrum β-lactamases and/or AmpC β-lactamases in food and food-producing animals. EFSA J. 2011, 9, 2322. [Google Scholar] [CrossRef]
  16. EFSA; ECDC. The European Union Summary Report on Antimicrobial Resistance in zoonotic and indicator bacteria from humans, animals and food in 2019–2020. EFSA J 2022, 20, e07209. [Google Scholar] [CrossRef]
  17. Olsen, R.H.; Bisgaard, M.; Lohren, U.; Robineau, B.; Christensen, H. Extended-spectrum beta-lactamase-producing Escherichia coli isolated from poultry: A review of current problems, illustrated with some laboratory findings. Avian Pathol. 2014, 43, 199–208. [Google Scholar] [CrossRef]
  18. Cantón, R.; Coque, T.M. The CTX-M β-lactamase pandemic. Curr. Opin. Microbiol. 2006, 9, 466–475. [Google Scholar] [CrossRef]
  19. Coque, T.M.; Baquero, F.; Canton, R. Increasing prevalence of ESBL-producing Enterobacteriaceae in Europe. Eurosurveillance 2008, 13. [Google Scholar] [CrossRef]
  20. Reich, F.; Atanassova, V.; Haunhorst, E.; Klein, G. The effects of Campylobacter numbers in caeca on the contamination of broiler carcasses with Campylobacter. Int. J. Food Microbiol. 2008, 127, 116–120. [Google Scholar] [CrossRef] [PubMed]
  21. USDA. Livestock and Poultry: World Markets and Trade. 2023. Available online: https://usda.library.cornell.edu/concern/publications/73666448x (accessed on 31 August 2023).
  22. Althaus, D.; Zweifel, C.; Stephan, R. Analysis of a poultry slaughter process: Influence of process stages on the microbiological contamination of broiler carcasses. Ital. J. Food Saf. 2017, 6, 7097. [Google Scholar] [CrossRef] [PubMed]
  23. Buess, S.; Zurfluh, K.; Stephan, R.; Guldimann, C. Quantitative microbiological slaughter process analysis in a large-scale Swiss poultry abattoir. Food Control 2019, 105, 86–93. [Google Scholar] [CrossRef]
  24. Göksoy, E.O.; Kirkan, S.; Kok, F. Microbiological quality of broiler carcasses during processing in two slaughterhouses in Turkey. Poult. Sci. 2004, 83, 1427–1432. [Google Scholar] [CrossRef] [PubMed]
  25. Chen, S.H.; Fegan, N.; Kocharunchitt, C.; Bowman, J.P.; Duffy, L.L. Impact of poultry processing operating parameters on bacterial transmission and persistence on chicken carcasses and their shelf life. Appl. Environ. Microbiol. 2020, 86, e00594-20. [Google Scholar] [CrossRef]
  26. Pacholewicz, E.; Liakopoulos, A.; Swart, A.; Gortemaker, B.; Dierikx, C.; Havelaar, A.; Schmitt, H. Reduction of extended-spectrum-β-lactamase-and AmpC-β-lactamase-producing Escherichia coli through processing in two broiler chicken slaughterhouses. Int. J. Food Microbiol. 2015, 215, 57–63. [Google Scholar] [CrossRef] [PubMed]
  27. Pacholewicz, E.; Swart, A.; Schipper, M.; Gortemaker, B.G.; Wagenaar, J.A.; Havelaar, A.H.; Lipman, L.J. A comparison of fluctuations of Campylobacter and Escherichia coli concentrations on broiler chicken carcasses during processing in two slaughterhouses. Int. J. Food Microbiol. 2015, 205, 119–127. [Google Scholar] [CrossRef] [PubMed]
  28. Singh, M.; Rama, E.N. Safety management and pathogen monitoring in poultry slaughterhouse operations: The case of the United States. In Achieving Sustainable Production of Poultry Meat; Burleigh Dodds Science Publishing: Cambridge, UK, 2017; Volume 1, pp. 109–162. [Google Scholar]
  29. Cason, J.; Hinton, A., Jr.; Ingram, K. Coliform, Escherichia coli, and salmonellae concentrations in a multiple-tank, counterflow poultry scalder. J. Food Prot. 2000, 63, 1184–1188. [Google Scholar] [CrossRef]
  30. Heemskerk, W. Preventive strategies during slaughter of poultry, to improve food safety. In Proceedings of the XVII European Symposium on the Quality of Poultry Meat and XI European Symposium on the Quality of Eggs and Egg Products, Doorwerth, The Netherlands, 23–26 May 2005; pp. 23–26. [Google Scholar]
  31. Svobodová, I.; Bořilová, G.; Hulánková, R.; Steinhauserová, I. Microbiological quality of broiler carcasses during slaughter processing. Acta Vet. Brno 2012, 81, 37–42. [Google Scholar] [CrossRef]
  32. EFSA; ECDC. The European Union Summary Report on Antimicrobial Resistance in zoonotic and indicator bacteria from humans, animals and food in 2020/2021. EFSA J. 2023, 21, e07867. [Google Scholar] [CrossRef]
  33. Reich, F.; Atanassova, V.; Klein, G. Extended-spectrum β-lactamase–and AmpC-producing enterobacteria in healthy broiler chickens, Germany. Emerg. Infect. Dis. 2013, 19, 1253. [Google Scholar] [CrossRef] [PubMed]
  34. Dierikx, C.; van der Goot, J.; Fabri, T.; van Essen-Zandbergen, A.; Smith, H.; Mevius, D. Extended-spectrum-β-lactamase-and AmpC-β-lactamase-producing Escherichia coli in Dutch broilers and broiler farmers. J. Antimicrob. Chemother. 2013, 68, 60–67. [Google Scholar] [CrossRef] [PubMed]
  35. Laube, H.; Friese, A.; von Salviati, C.; Guerra, B.; Kasbohrer, A.; Kreienbrock, L.; Roesler, U. Longitudinal monitoring of extended-spectrum-beta-lactamase/AmpC-producing Escherichia coli at German broiler chicken fattening farms. Appl. Environ. Microbiol. 2013, 79, 4815–4820. [Google Scholar] [CrossRef] [PubMed]
  36. Laube, H.; Friese, A.; Von Salviati, C.; Guerra, B.; Rösler, U. Transmission of ESBL/AmpC-producing Escherichia coli from broiler chicken farms to surrounding areas. Vet. Microbiol. 2014, 172, 519–527. [Google Scholar] [CrossRef]
  37. Projahn, M.; Daehre, K.; Semmler, T.; Guenther, S.; Roesler, U.; Friese, A. Environmental adaptation and vertical dissemination of ESBL-/pAmpC-producing Escherichia coli in an integrated broiler production chain in the absence of an antibiotic treatment. Microb. Biotechnol. 2018, 11, 1017–1026. [Google Scholar] [CrossRef] [PubMed]
  38. Doi, Y.; Paterson, D.; Egea, P.; Pascual, A.; López-Cerero, L.; Navarro, M.; Adams-Haduch, J.; Qureshi, Z.; Sidjabat, H.; Rodriguez-Bano, J. Extended-spectrum and CMY-type b-lactamase-producing Escherichia coli in clinical samples and retail meat from Pittsburgh, USA and Seville, Spain. Clin. Microbiol. Infect. 2010, 16, 33–38. [Google Scholar] [CrossRef]
  39. Eltai, N.O.; Yassine, H.M.; El-Obeid, T.; Al-Hadidi, S.H.; Al Thani, A.A.; Alali, W.Q. Prevalence of antibiotic-resistant Escherichia coli isolates from local and imported retail chicken carcasses. J. Food Prot. 2020, 83, 2200–2208. [Google Scholar] [CrossRef]
  40. Evers, E.G.; Pielaat, A.; Smid, J.H.; van Duijkeren, E.; Vennemann, F.B.; Wijnands, L.M.; Chardon, J.E. Comparative Exposure Assessment of ESBL-Producing Escherichia coli through Meat Consumption. PLoS ONE 2017, 12, e0169589. [Google Scholar] [CrossRef]
  41. Projahn, M.; Pacholewicz, E.; Becker, E.; Correia-Carreira, G.; Bandick, N.; Kaesbohrer, A. Reviewing interventions against Enterobacteriaceae in broiler processing: Using old techniques for meeting the new challenges of ESBL E. coli? Biomed. Res. Int. 2018, 2018, 7309346. [Google Scholar] [CrossRef] [PubMed]
  42. Pacholewicz, E.; Swart, A.; Wagenaar, J.A.; Lipman, L.J.; Havelaar, A.H. Explanatory variables associated with Campylobacter and Escherichia coli concentrations on broiler chicken carcasses during processing in two slaughterhouses. J. Food Prot. 2016, 79, 2038–2047. [Google Scholar] [CrossRef]
  43. Marel. Product: Aeroscalder. Available online: https://marel.com/en/products/aeroscalder (accessed on 15 November 2021).
  44. CLSI. Performance Standards for Antimicrobial Susceptibility Testing; 21st Informational Supplement; CLSI document M100-S21; Clinical and Laboratory Standards Institute: Wayne, PA, USA, 2011; ISBN 1-56238-742-1. [Google Scholar]
  45. Roschanski, N.; Fischer, J.; Guerra, B.; Roesler, U. Development of a multiplex real-time PCR for the rapid detection of the predominant beta-lactamase genes CTX-M, SHV, TEM and CIT-type AmpCs in Enterobacteriaceae. PLoS ONE 2014, 9, e100956. [Google Scholar] [CrossRef] [PubMed]
  46. Projahn, M.; Daehre, K.; Roesler, U.; Friese, A. Extended-spectrum-beta-lactamase-and plasmid-encoded cephamycinase-producing enterobacteria in the broiler hatchery as a potential mode of pseudo-vertical transmission. Appl. Environ. Microbiol. 2017, 83, e02364-16. [Google Scholar] [CrossRef] [PubMed]
  47. Michael, G.B.; Freitag, C.; Wendlandt, S.; Eidam, C.; Feßler, A.T.; Lopes, G.V.; Kadlec, K.; Schwarz, S. Emerging issues in antimicrobial resistance of bacteria from food-producing animals. Future Microbiol. 2015, 10, 427–443. [Google Scholar] [CrossRef]
  48. Valentin, L.; Sharp, H.; Hille, K.; Seibt, U.; Fischer, J.; Pfeifer, Y.; Michael, G.B.; Nickel, S.; Schmiedel, J.; Falgenhauer, L.; et al. Subgrouping of ESBL-producing Escherichia coli from animal and human sources: An approach to quantify the distribution of ESBL types between different reservoirs. Int. J. Med. Microbiol. 2014, 304, 805–816. [Google Scholar] [CrossRef]
  49. Seliwiorstow, T.; Baré, J.; Berkvens, D.; Van Damme, I.; Uyttendaele, M.; De Zutter, L. Identification of risk factors for Campylobacter contamination levels on broiler carcasses during the slaughter process. Int. J. Food Microbiol. 2016, 226, 26–32. [Google Scholar] [CrossRef]
  50. Leverstein-van Hall, M.A.; Dierikx, C.M.; Cohen Stuart, J.; Voets, G.M.; van den Munckhof, M.P.; van Essen-Zandbergen, A.; Platteel, T.; Fluit, A.C.; van de Sande-Bruinsma, N.; Scharinga, J.; et al. Dutch patients, retail chicken meat and poultry share the same ESBL genes, plasmids and strains. Clin. Microbiol. Infect. 2011, 17, 873–880. [Google Scholar] [CrossRef]
  51. Wadepohl, K.; Muller, A.; Seinige, D.; Rohn, K.; Blaha, T.; Meemken, D.; Kehrenberg, C. Association of intestinal colonization of ESBL-producing Enterobacteriaceae in poultry slaughterhouse workers with occupational exposure-A German pilot study. PLoS ONE 2020, 15, e0232326. [Google Scholar] [CrossRef]
  52. Gregova, G.; Kmetova, M.; Kmet, V.; Venglovsky, J.; Feher, A. Antibiotic resistance of Escherichia coli isolated from a poultry slaughterhouse. Ann. Agric. Environ. Med. 2012, 19, 75–77. [Google Scholar]
  53. Friese, A.; Schulz, J.; Laube, H.; von Salviati, C.; Hartung, J.; Roesler, U. Faecal occurrence and emissions of livestock-associated methicillin-resistant Staphylococcus aureus (laMRSA) and ESbl/AmpC-producing E. coli from animal farms in Germany. Berl. Munch. Tierarztl. Wochenschr. 2013, 126, 175–180. [Google Scholar]
  54. Daehre, K.; Projahn, M.; Semmler, T.; Roesler, U.; Friese, A. Extended-spectrum beta-lactamase-/AmpC beta-lactamase-producing Enterobacteriaceae in broiler farms: Transmission dynamics at farm level. Microb. Drug Resist. 2018, 24, 511–518. [Google Scholar] [CrossRef]
  55. Jakobsen, L.; Garneau, P.; Kurbasic, A.; Bruant, G.; Stegger, M.; Harel, J.; Jensen, K.S.; Brousseau, R.; Hammerum, A.M.; Frimodt-Møller, N. Microarray-based detection of extended virulence and antimicrobial resistance gene profiles in phylogroup B2 Escherichia coli of human, meat and animal origin. J. Med. Microbiol. 2011, 60, 1502–1511. [Google Scholar] [CrossRef]
  56. Jakobsen, L.; Kurbasic, A.; Skjøt-Rasmussen, L.; Ejrnæs, K.; Porsbo, L.J.; Pedersen, K.; Jensen, L.B.; Emborg, H.-D.; Agersø, Y.; Olsen, K.E. Escherichia coli isolates from broiler chicken meat, broiler chickens, pork, and pigs share phylogroups and antimicrobial resistance with community-dwelling humans and patients with urinary tract infection. Foodborne Pathog. Dis. 2010, 7, 537–547. [Google Scholar] [CrossRef] [PubMed]
  57. Johnson, J.R.; Kuskowski, M.A.; Gajewski, A.; Soto, S.; Horcajada, J.P.; De Anta, M.T.J.; Vila, J. Extended virulence genotypes and phylogenetic background of Escherichia coli isolates from patients with cystitis, pyelonephritis, or prostatitis. J. Infect. Dis. 2005, 191, 46–50. [Google Scholar] [CrossRef]
  58. Hutchison, M.L.; Harrison, D.; Tchorzewska, M.A.; Gonzalez-Bodi, S.; Madden, R.H.; Corry, J.E.L.; Allen, V.M. Quantitative determination of Campylobacter on broilers along 22 United Kingdom processing lines to identify potential process control points and cross-contamination from colonized to uncolonized flocks. J. Food Prot. 2022, 85, 1696–1707. [Google Scholar] [CrossRef] [PubMed]
  59. Berrang, M.; Buhr, R.; Cason, J.; Dickens, J. Broiler carcass contamination with Campylobacter from feces during defeathering. J. Food Prot. 2001, 64, 2063–2066. [Google Scholar] [CrossRef]
  60. Abu-Ruwaida, A.; Sawaya, W.; Dashti, B.; Murad, M.; Al-Othman, H. Microbiological quality of broilers during processing in a modern commercial slaughterhouse in Kuwait. J. Food Prot. 1994, 57, 887–892. [Google Scholar] [CrossRef] [PubMed]
  61. Ghodousi, A.; Bonura, C.; Di Noto, A.M.; Mammina, C. Extended-spectrum ß-lactamase, AmpC-producing, and fluoroquinolone-resistant Escherichia coli in retail broiler chicken meat, Italy. Foodborne Pathog. Dis. 2015, 12, 619–625. [Google Scholar] [CrossRef] [PubMed]
Microorganisms 11 02541 g001
Figure 1. Extended-spectrum β-lactamase (ESBL)-producing E. coli isolates from breast skin samples from Abattoir 1 (n = 117; using a conventional immersion scalder), Abattoir 2 (n = 62; using immersion scalding with thermal treatment of the scalding water), and Abattoir 3 (n = 128, operating the AeroScalder®), and number of isolates encoding ESBL genes detected at the sampling positions.
Figure 1. Extended-spectrum β-lactamase (ESBL)-producing E. coli isolates from breast skin samples from Abattoir 1 (n = 117; using a conventional immersion scalder), Abattoir 2 (n = 62; using immersion scalding with thermal treatment of the scalding water), and Abattoir 3 (n = 128, operating the AeroScalder®), and number of isolates encoding ESBL genes detected at the sampling positions.
Microorganisms 11 02541 g001
Table 1. Test discs used for agar diffusion test.
Table 1. Test discs used for agar diffusion test.
AntimicrobialAbbreviationConcentrationManufacturer
CefotaximeCTX30 µgThermo Fisher Diagnostics GmbH (former Oxoid Deutschland GmbH), Wesel, Germany
CefoxitinFOX30 µg
CeftazidimeCAZ30 µg
MeropenemMRP10 µg
Cefotaxime and clavulanic acidCTL30/10 µgBestbion, Hürth, Germany
Table 2. Detected phylogroups of extended-spectrum β-lactamase (ESBL)-producing E. coli isolates at Abattoir 1 (using conventional immersion scalding; n = 117), Abattoir 2 (using conventional immersion scalding with thermal treatment of the scalding water; n = 62), and Abattoir 3 (using the AeroScalder®; n = 128) per sampling position.
Table 2. Detected phylogroups of extended-spectrum β-lactamase (ESBL)-producing E. coli isolates at Abattoir 1 (using conventional immersion scalding; n = 117), Abattoir 2 (using conventional immersion scalding with thermal treatment of the scalding water; n = 62), and Abattoir 3 (using the AeroScalder®; n = 128) per sampling position.
PhylogroupSampling Position
Before ScaldingAfter ScaldingAfter PluckingBefore ChillingAfter ChillingTotalTotal Overall
Abattoir 1
(conventional
immersion scalder)		A000101117
A/C7375628
B1520108
B2200013
D/E27121514876
F100001
not assigned to any group000000
Abattoir 2
(conventional
immersion scalder with thermal treatment of the scalding water)		A10000162
A/C004206
B148811738
B20184114
D/E300003
F000000
not assigned to any group000000
Abattoir 3
(AeroScalder®)		A000000128
A/C9823325
B1121044636
B2201003
D/E2214611861
F000000
not assigned to any group120003
Table 3. Resistance profiles of 20 E. coli phylogroup B2 isolates per abattoir and sampling position.
Table 3. Resistance profiles of 20 E. coli phylogroup B2 isolates per abattoir and sampling position.
Lab-IDSampling DayAbattoirSampling PositionFOXCAZCTXMRPCTL-CTX Diameter (mm)
121551before scaldingSISS8
12165before scaldingSIRS10
38010after chillingSSRS14
98442after scaldingSSRS17
9884after pluckingSIRS15
9904after pluckingSSRS11
9924after pluckingSSRS12
9944after pluckingSRRS10
10204after pluckingSSRS9
10224after pluckingSSRS9
10244after pluckingSIRS12
10264after pluckingSIRS16
9964before chillingSSRS12
9984before chillingSSRS15
10004before chillingSn.d.RS16
10304before chillingSSRS16
638after chillingRRRS6
70223before scaldingSIRS15
703-12before scaldingSSRS14
6892after pluckingSIRS14
ID—laboratory identification number; FOX—cefoxitin 30 µg; CAZ—ceftazidime 30 µg; CTX—cefotaxime 30 µg; CTL—cefotaxime and clavulanic acid 30/10 µg; S—susceptible; I—intermediate; R—resistant; n.d.—no data.
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Langkabel, N.; Burgard, J.; Freter, S.; Fries, R.; Meemken, D.; Ellerbroek, L. Detection of Extended-Spectrum β-Lactamase (ESBL) E. coli at Different Processing Stages in Three Broiler Abattoirs. Microorganisms 2023, 11, 2541. https://doi.org/10.3390/microorganisms11102541

AMA Style

Langkabel N, Burgard J, Freter S, Fries R, Meemken D, Ellerbroek L. Detection of Extended-Spectrum β-Lactamase (ESBL) E. coli at Different Processing Stages in Three Broiler Abattoirs. Microorganisms. 2023; 11(10):2541. https://doi.org/10.3390/microorganisms11102541

Chicago/Turabian Style

Langkabel, Nina, Janine Burgard, Sabrina Freter, Reinhard Fries, Diana Meemken, and Lüppo Ellerbroek. 2023. "Detection of Extended-Spectrum β-Lactamase (ESBL) E. coli at Different Processing Stages in Three Broiler Abattoirs" Microorganisms 11, no. 10: 2541. https://doi.org/10.3390/microorganisms11102541

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