Search Results (83)

The demand for wild animal meat, popularly called “bushmeat”, serves as a driving force behind the emergence of infectious diseases, potentially transmitting a variety of pathogenic bacteria to humans through handling and consumption. This study investigated the microbial load and bacterial diversity in bushmeat sourced from a prominent bushmeat market in Kumasi, Ghana. Carcasses of 61 wild animals, including rodents (44), antelopes (14), and African civets (3), were sampled for microbiological analysis. These samples encompassed meat, intestines, and anal and oral swabs. The total aerobic bacteria plate count (TPC), Enterobacteriaceae count (EBC), and fungal counts were determined. Bacterial identification was conducted using MALDI-TOF biotyping. Fungal counts were the highest across all animal groups, with African civets having 11.8 ± 0.3 log₁₀ CFU/g and 11.9 ± 0.2 log₁₀ CFU/g in intestinal and meat samples, respectively. The highest total plate count (TPC) was observed in rodents, both in their intestines (10.9 ± 1.0 log₁₀ CFU/g) and meat (10.9 ± 1.9 log₁₀ CFU/g). In contrast, antelopes exhibited the lowest counts across all categories, particularly in EBC from intestinal samples (6.1 ± 1.5 log₁₀ CFU/g) and meat samples (5.6 ± 1.2 log₁₀ CFU/g). A comprehensive analysis yielded 524 bacterial isolates belonging to 20 genera, with Escherichia coli (18.1%) and Klebsiella spp. (15.5%) representing the most prevalent species. Notably, the detection of substantial microbial contamination in bushmeat underscores the imperative for a holistic One Health approach to enhance product quality and mitigate risks associated with its handling and consumption. Full article

Milk is frequently susceptible to contamination by potential pathogens, posing risks to both food safety and public health. Cheesemaking often relies on raw milk, where microbial communities—including Staphylococcus xylosus—can play a dual role: (i) contributing to fermentation and (ii) acting as opportunistic pathogens that can be often present in subclinical mastitis and be subjected to carry over in dairy products. In this study, Staphylococcus xylosus was isolated from raw bovine milk (preclinical mastitis) and identified via matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (Biotyper scores: 1.87–2.19). Its susceptibility to erythromycin and to an essential oil blend composed of Myrtus communis, Salvia officinalis, and Cistus ladanifer was evaluated. The essential oil blend produced inhibition zones ranging from 9 mm to 13.3 mm, indicating moderate antibacterial activity. Further Minimum Inhibitory Concentration analysis revealed that Myrtus communis, Salvia officinalis, and the essential oil blend inhibited Staphylococcus xylosus growth at concentrations between 0.5 and 0.25 percent, while Cistus ladanifer required higher levels (1 to 0.5 percent). These findings suggest that selected essential oils—especially in combination—hold promise as complementary antimicrobial agents in food safety and antimicrobial resistance mitigation efforts. Full article

The emergence of antimicrobial resistance and the increasing demand for a healthier lifestyle have set new goals for science and industry. In the search for new, more effective, and environmentally friendly antimicrobial agents, special attention is being paid to natural resources. In this regard, essential oils derived from plants, which are widely used in the cosmetic, food, and pharmaceutical industries, are one of the solutions. In view of the above, this study aims to investigate the biological effects of Abies alba essential oil (AAEO). The chemical profile of AAEO was evaluated by GC/MS analysis, which revealed a high abundance of limonene (52.2%) and α-pinene (36.2%). Antioxidant activity evaluation showed a higher potential of AAEO in scavenging ABTS radical species with an IC₅₀ value of 1.18 ± 0.05 mg/mL. In vitro antimicrobial activity was determined by disc diffusion and minimum inhibitory concentration assays and showed that AAEO was more efficient in inhibiting the growth of G⁺ bacterial species. On contrary, in situ evaluations of antimicrobial effects of AAEO on different food models (strawberry, kiwi, white radish, and beetroot) resulted in more efficient suppression of G⁻ bacterial species. Although AAEO showed low effects on yeasts determined by in vitro methods, in situ investigations showed its higher potential in eradication of Candida yeast. The antibiofilm properties of the AAEO matrix were determined by means of crystal violet assay and MALDI-TOF MS Biotyper analysis against biofilm-forming Salmonella enterica. The analysis performed led to the conclusion that AAEO, when applied prior to biofilm formation, may contribute to the removal of planktonic cells and alter the abiotic surface, thereby reducing the suitability of Salmonella enterica for microbial attachment. Full article

Background/Objectives: The present study was aimed at documenting S. maltophilia occurrence in dogs with skin ailments, investigating its virulence, biofilm-forming ability, antimicrobial susceptibility, and zoonotic potential to inform preventive and therapeutic strategies against multidrug resistant S. maltophilia infections. Methods: Skin swabs (n = 300) were collected from dogs with dermatological ailments. Isolation was performed using selective media and confirmed with molecular methods, validated by MALDI Biotyper. Antimicrobial susceptibility testing and efflux activity assessment were conducted. Resistance genes related to sulfonamides, quinolones, and β-lactams were screened. Virulence was assessed by biofilm formation, motility, and virulence gene profiling. Results: In total, 15 S. maltophilia (5%) isolates were identified. All 15 isolates were susceptible to trimethoprim-sulfamethoxazole, enrofloxacin, gatifloxacin, levofloxacin, minocycline, and tigecycline, but resistant to cefpodoxime and aztreonam. The following resistance genes qnr (93.3%), bla_OXA-48 (46.7%), bla_KPC (33.3%), bla_NDM (33.3%), bla_CTX-M (20%), bla_SHV (20%), and bla_TEM (6.7%) were detected. All 15 isolates displayed high efflux activity. Overall, 9 isolates (60%) were strong biofilm producers, and 6 (40%) were moderate. Virulence genes such as virB, motA, rmlA, and fliC were present in all 15 isolates, with others varying in frequency. All isolates exhibited swimming motility. Heat map clustering showed diverse profiles, with no identical isolate patterns. Correlation analysis indicated positive associations between several antimicrobial resistance and virulence genes. Conclusions: This study underscores the zoonotic potential of S. maltophilia from dogs, advocating for a One Health approach to mitigate infection risks and limit the spread of virulent multidrug resistant pathogens. Full article

Identification of mycobacterial infections for both Mycobacterium tuberculosis and non-tuberculosis mycobacteria is important for effective patient care. Matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS) is a promising tool that is used in many clinical laboratories for the identification of bacteria and yeast. This study evaluates the impact of growth media on the performance of the MALDI Biotyper^® MBT smart MS for mycobacteria identification. Increased rates of identification, particularly in non-rapid growers and pigment producers, and higher confidence scores were generated in mycobacteria isolated from solid agar, rather than liquid broth. Testing each isolate in triplicate can increase yield of detection. Using the Bruker MBT Mycobacteria Kit to process our samples for testing on the Bruker MALDI Biotyper^® instrument generated precise and accurate mycobacteria identification. These findings emphasize the importance of optimizing mycobacterial specimen processing workflows to include appropriate culture media, which can enhance mycobacterial identification and improve diagnostic accuracy. Full article

The goal of the present study was to analyze Acinetobacter baumannii strains isolated from hospitalized patients in the period of the COVID-19 pandemic by phenotypic and molecular methods and evaluate their antimicrobial resistance patterns and biofilm production. Forty-seven strains were isolated in 2021–2022 from a hospital in Brazil, and were identified by VITEK^®2, MALDI-TOF/MS (VITEK MS^® and MALDI Biotyper^®), and 16S rRNA sequencing. Fourier-transform infrared (FTIR) spectroscopy was applied for typing and antimicrobial susceptibility testing (AST). In addition, biofilm formation and disinfectant tolerance tests were used. All methods accurately identified all the A. baumannii strains. FTIR typing identified 23 different profiles and 11 clusters, as well as differentiated between the strains from patients with and without COVID-19. Most strains exhibited resistance to the drugs tested, 91.5% of the strains were classified as XDR, 6.4% of the strains were MDR and only 1 strain was classified as non-MDR. Over half of the strains (n = 27, 57.4%) produced biofilms on polystyrene. Sodium hypochlorite (1.0%/15 min) was the best option for effective disinfection. Overall, this study will lay the foundation for further research on effective cleaning protocols for the eradication of A. baumannii biofilms, as well as the use of FTIR for pathogen surveillance in healthcare settings. Full article

Escherichia albertii is a lactose-negative Escherichia that causes gastritis and enteritis in humans. An analysis of possible sources of infection points out that poultry may be a significant reservoir for this pathogen. The question of whether E. albertii can cause infections in poultry is still unanswered. Our article describes the isolation of E. albertii, for the first time in Russia, from the intestines of birds on a quail farm and a characterization of obtained cultures. We isolated different bacteria from pathological poultry material using bacteriological methods and ruled them out as probable causes for enteritis. The biochemical identification of E. albertii and antibiotic sensitivity were performed using a Vitek-2 Compact instrument. Bacterial identification was carried out using the MALDI-TOF Biotyper instrument. E. albertii-specific genes, virulence factor genes, and microcin genes were detected by real-time PCR. It was concluded that E. albertii isolated from sites of intestinal inflammation are a potential cause of enteritis and high poultry mortality—up to 15% of total livestock for 10- to 20-day-old quails. One of the E. albertii culture differed from the main group of Escherichia by its biochemical properties, and subsequent PCR analysis showed a lack of the intimin gene (eae). We describe the first occasion of infection caused by E. albertii in industrial quails. During the study, it was found that, according to the molecular–genetic and phenotypic properties of isolated strains in quails, there were at least two clonal groups of E. albertii differing in antibiotic resistance, biochemical indices, and presence of the eae (intimin) gene. Full article

European hedgehogs are an important reservoir for many pathogens of health interest. Since hedgehogs live in close contact with humans, potential zoonotic fungi raise significant public health concerns, especially in areas with a high hedgehog density. From 2020 to 2023, 134 hedgehogs were surveyed for potential zoonotic fungi. Non-invasive methods were used, such as brushing live animals with a sterile toothbrush and taking oral and rectal swabs from deceased ones (86 animals). Dermatophytes were cultured on Dermasel agar and identified using molecular tools, while yeasts were isolated on Sabouraud agar with chloramphenicol and determined using Candida Chromogenic agar (MicroBiolDiagnostici^®, Cagliari, Italy) and MALDI-TOF (Microflex LT Smart Biotyper with FlexControlBiotyper 3.4 software, Bruker Daltonics, Bremen, Germany). Minimum inhibitory concentrations (MICs) were determined for Candida albicans isolates. Dermatophytes were found in just one hedgehog (0.8%, 95% C.I.: 0–0.04), identified as Paraphyton mirabile. Yeasts were detected in 22 of 86 hedgehogs (25.6%, 95% C.I.: 16.4–34.8), with 25 isolates obtained, including 21 Candida albicans, 2 Yarrowia lipolytica, 1 Rhodotorula mucilaginosa, and 1 Meyerozyma guilliermondii. All C. albicans isolates showed a high susceptibility to the antimycotic panel tested. Monitoring zoonotic fungi harbored by European hedgehogs, as well as raising public awareness on the topic, is of great importance for public health. Full article

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) is a widely adopted technique for bacterial and yeast identification in clinical laboratories but is less frequently applied to filamentous fungi due to inconsistent performance, limitations of commercial libraries, and variability of preparation methods. This study aimed to validate the efficiency of MALDI-TOF MS-based dermatophyte identification using the Bruker Biotyper system. Focusing on species from the Trichophyton, Nannizzia, Microsporum, and Epidermophyton genera, an in-house reference library was established and evaluated with clinical isolates. The expanded library, which combined the in-house and Bruker libraries, achieved significantly higher accuracy than the Bruker library alone, correctly identifying 90.7% (107/118) of isolates at the species level compared to 16.1% (19/118) by the Bruker library. This study presents an efficient, standardized MALDI-TOF MS protocol for routine dermatophyte identification and provides a review of the current status and influencing factors in MALDI-TOF MS-based dermatophyte identification strategies. Full article

According to the Regulation on the Quality of Fresh Raw Milk, up to 100,000 microorganisms/mL are allowed in milk obtained by the hygienic milking of healthy cows, which represents the natural microbiota of milk and has no negative impact on the overall quality of milk. However, with unprofessional handling during and after milking, milk is easily contaminated and becomes a potential medium for the growth and reproduction of microorganisms, some of which can be harmful to human health. Since the number of aerobic mesophilic bacteria in milk is one of the indicators of the hygienic quality of milk, their number and identification are fundamental in the control of raw milk from milk vending machines. From five different milk vending machines, 35 samples were collected, from which the total number of aerobic mesophilic bacteria was determined using the flow cytometry method and the classic method of counting colonies on a nutrient medium. Randomly selected colonies based on morphological differences (n = 700) were identified by comparing MALDI-TOF mass spectra with reference spectra stored in the microorganism library and processing using the MALDI Biotyper computer program. Thirty-eight genera and eighty-one bacterial species and five genera and seven fungal species were successfully identified. The species that predominate are Lactococcus lactis, Hafnia alvei, Escherichia coli, Leuconostoc mesenteroides, and Kluyveromyces lactis. By integrating advanced methods like flow cytometry and MALDI-TOF MS for precise microbial identification, this study highlights the need for enhanced monitoring and adherence to hygienic standards in raw milk vending machines. This approach not only safeguards public health but also supports consumer confidence in milk quality from vending machines. Full article

Escherichia coli and Shigella flexneri are challenging to differentiate using methods such as phenotyping, 16S rRNA sequencing, or protein profiling through matrix-assisted laser desorption/ionization mass spectrometry (MALDI MS) due to their close relatedness. This study explores the potential for identifying E. coli and S. flexneri by incorporating reference spectra of metabolite profiles, obtained via surface-assisted laser desorption/ionization mass spectrometry (SALDI MS) employing gold nanoparticles (AuNPs), into the Bruker Biotyper database. Metabolite extracts from E. coli and S. flexneri cells were prepared using liquid–liquid extraction in a chloroform–methanol–water system. The extracts were analyzed using Au-SALDI MS in positive ion mode, and reference spectra, compiled from 30 spectra for each bacterium, were added to the database. Identification of bacteria based on metabolite fingerprints in the Biotyper database produced correct results with scores exceeding 2.75. The results of Partial Least Squares-Discriminant Analysis (PLS-DA) demonstrated that the metabolomic approach could accurately differentiate the microorganisms under study. A panel of nine m/z values was also identified, each with an area under the ROC curve of above 0.8, enabling accurate identification of E. coli and S. flexneri. A search of metabolite databases allowed the following compounds to be assigned to the selected m/z values: N-acetylputrescine, arginine, 2-maleylacetate, benzoyl phosphate, N8-acetylspermidine, alanyl-glutamate, 4-hydroxy-2,3,4,5-tetrahydrodipicolinate, and sucrose. The analyses showed that identification of bacteria based on metabolite profiles obtained by the Au-SALDI MS method is feasible and can be useful for distinguishing closely related microorganisms that are difficult to differentiate by other techniques. Full article

A Gram-positive, aerobic, rod-shaped and spore-forming bacterium strain designation, B190/17, was isolated from an air monitoring sample of a Brazilian immunobiological production facility in 2017. The strain was not identifiable by biochemical methodology VITEK^® 2 or by MALDI-TOF MS with VITEK^® MS RUO and MALDI Biotyper^®. The 16S rRNA gene sequencing results showed 98.51% similarity with Bacillus wudalianchiensis FJAT 27215^T, 98.28% with ‘Bacillus aerolatus’ CX 253^T, 97.96% with Bacillus badius MTCC 1458^T, 97.63% with Bacillus xiapuensis FJAT 46582^T and 97.21% with Bacillus thermotolerans SGZ8^T. Biochemical data showed that the strain was alanine arylamidase-, Ala-Phe-Pro arylamidase-, ELLMAN (cysteine residues)-, leucine arylamidase-, phenyalanine arylamidase- and tyrosine arylamidase-positive. The genomic DNA G+C% content of B190/17 was 41.6 mol%. The phylogenetic, genomic taxonomy and biochemical tests suggested that B190/17 represents a novel species and should be classified as the type strain of a novel Bacillus species. The name Bacillus lumedeiriae sp. nov. was proposed. After characterization, B190/17 was added to the MALDI Biotyper^® database as Bacillus lumedeiriae sp. nov. Full article

Background/Objectives: Intestinal colonization by multidrug-resistant (MDR) bacteria is considered one of the main risk factors for invasive infections in the hematopoietic stem-cell transplant (HSCT) setting, associated with hard-to-eradicate microorganisms. The aim of this study was to assess the rate of intestinal colonization by MDR bacteria and their microbial spectrum in a group of post-HSCT patients to study the genetic determinants of beta-lactam and glycopeptide resistance in the recovered isolates, as well as to determine the epidemiological relation between them. Methods: The intestinal colonization status of 74 patients admitted to the transplantation center of University Hospital “St. Marina”—Varna in the period January 2019 to December 2021 was investigated. Stool samples/rectal swabs were screened for third-generation cephalosporin and/or carbapenem-resistant Gram-negative bacteria, methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant enterococci (VRE), and Stenotrophomonas maltophilia. Identification and antimicrobial susceptibility testing were performed by Phoenix (BD, Sparks, MD, USA) and MALDI Biotyper sirius (Bruker, Bremen, Germany). Molecular genetic methods (PCR, DNA sequencing) were used to study the mechanisms of beta-lactam and glycopeptide resistance in the collected isolates, as well as the epidemiological relationship between them. Results: A total of 28 patients (37.8%) were detected with intestinal colonization by MDR bacteria. Forty-eight non-duplicate MDR bacteria were isolated from their stool samples. Amongst them, the Gram-negative bacteria prevailed (68.8%), dominated by ESBL-producing Escherichia coli (30.3%), and followed by carbapenem-resistant Pseudomonas sp. (24.2%). The Gram-positive bacteria were represented exclusively by Enterococcus faecium (31.2%). The main beta-lactam resistance mechanisms were associated with CTX-M and VIM production. VanA was detected in all vancomycin-resistant enterococci. A clonal relationship was observed among Enterobacter cloacae complex and among E. faecium isolates. Conclusions: To the best of our knowledge, this is the first Bulgarian study that presents detailed information about the prevalence, resistance genetic determinants, and molecular epidemiology of MDR gut-colonizing bacteria in HSCT patients. Full article

This study aimed to characterize Pseudomonas aeruginosa strains isolated from hospitalized patients during the COVID-19 pandemic. This was achieved using phenotypic and molecular techniques, including their antimicrobial resistance profile and biofilm formation. Eighteen strains were isolated from a hospital in Rio de Janeiro, Brazil, and identified by VITEK^®2, MALDI-TOF/MS (VITEK MS^® and MALDI Biotyper^®), and 16S rRNA sequencing. Fourier-transform infrared (FTIR) spectroscopy, antimicrobial susceptibility testing, and biofilm formation and disinfectant tolerance tests were applied to evaluate the virulence characteristics of the strains. VITEK^®2 (≥99%), VITEK MS^® (≥82.7%), and MALDI Biotyper^® (score ≥ 2.01) accurately identified the P. aeruginosa strains, but 16S rRNA sequencing did not differentiate the species P. aeruginosa from P. paraeruginosa. FTIR typing identified three different clusters, but no correlation between the phenotypical or antimicrobial susceptibility testing patterns was found. Most strains exhibited resistance to various antimicrobials. The exceptions were sensitivity to amikacin and norfloxacin, and consequently, these could be considered potential treatment options. Most strains (n = 15, 83.3%) produced biofilms on polystyrene. Sodium hypochlorite treatment (0.5%/15 min) was shown to be the most effective disinfectant for biofilm elimination. P. aeruginosa biofilm formation and tolerance to disinfectants demonstrate the need for effective cleaning protocols to eliminate contamination by this organism in the hospital environment and medical equipment. Full article

Sustainable management practices are crucial for the longevity of a monoculture vineyard, especially in the context of a changing climate. Therefore, soil management practices in a vineyard (T: tillage, T+FYM: tillage + farmyard manure, G: grass strips, G+NPK1: grass strips + rational rates of NPK, and G+NPK2: grass strips + higher rates of NPK) were tested in a temperate climate of Slovakia (Central Europe) under specific soil conditions (Rendzic Leptosol). We investigated the influence of continuous cropping on soil chemical properties and microbial communities during the dry and warm year of 2022. The results showed that the soil pH was higher by 19%, 21%, 24% and 13% in T, T+FYM, G and G+NPK1, respectively, compared to G+NPK2. The lowest soil organic matter (SOM) content was found in T, and it increased in the following order: T < T+FYM < G+NPK2 < G+NPK1 < G. Similarly, the lowest abundance of soil culturable bacteriota was found in T and it increased in the following order: T < T+FYM = G+NPK2 < G+NPK1< G. Culturable bacteriota was identified using mass spectrometry (MALDI-TOF MS Biotyper). The most numerous species group was Bacillus, followed by Lactobacillus > Staphylococcus > Pseudomonas. The most frequently isolated species were Bacillus megaterium (16.55%), Bacillus cereus (5.80%), Bacillus thuringiensis (4.87%), and Bacillus simplex (4.37%). Positive relationships between SOM and soil culturable bacteriota were found in the G and G+NPK1 treatments. Temperature also affected soil culturable bacteriota in all soil management practices, most significantly in G+NPK1. Overall, the best scenario for the sustainable management of a productive vineyard is the use of grass strips. Full article