Search Results (187)

Background: The spread of ESBL-producing Enterobacteriaceae (ESBL-PE) strains in food poses a potential risk to human health. The aim of the study was to determine the occurrence of ESBL-PE and to investigate their distribution on foods. Methods: A total of 1000 food samples, including both raw and ready-to-eat products, was analyzed for the presence of ESBL-producing Enterobacteriaceae using chromogenic selective agar. Antibiotic resistance in the isolated strains was assessed using conventional methods, while whole-genome sequencing was employed to predict antimicrobial resistance and virulence genes. Results: The overall occurrence of ESBL-PE strains was 2.8%, with the highest contamination in raw meat samples (10%). A total of 31 multidrug-resistant (MDR) strains was isolated, mainly Escherichia coli, followed by Klebsiella pneumoniae, Salmonella enterica, and Enterobacter hormaechei. All strains exhibited high levels of resistance to at least four different β-lactam antibiotics, as well as to other antimicrobial classes including sulfonamides, tetracyclines, aminoglycosides, and quinolones. Whole-genome sequencing identified 63 antimicrobial resistance genes, with bla_CTX-M being the most prevalent ESBL gene. Twenty-eight (90%) isolates carried Inc plasmids, known vectors of multiple antimicrobial resistance genes, including those associated with ESBLs. Furthermore, several virulence genes were identified. Conclusions: The contamination of food with ESBL-PE represents a potential public health risk, underscoring the importance of the implementation of genomic surveillance to monitor and control the spread of antimicrobial resistance. Full article

Background: This study aimed to (a) assess the prevalence of multidrug-resistant (MDR) Enterobacteriaceae in the waters of two rivers and wastewater treatment plants (WWTPs) in a region of Catalonia, Spain; (b) genetically characterize the MDR strains; and (c) compare extended-spectrum β-lactamase (ESBL)-producing Escherichia coli isolates from environmental and human sources. Methods: A total of 62 samples were collected from the influent and effluent of 31 WWTPs and 29 river water samples from 11 sites. Simultaneously, 382 hospitalized patients were screened for MDR Enterobacteriaceae using rectal swabs. All isolates underwent antibiotic susceptibility testing and whole-genome sequencing. Results: MDR Enterobacteriaceae were detected in 48.4% of WWTP samples, with 18.5% ESBL-producing E. coli and 1.5% (one sample) OXA-48-producing K. pneumoniae in influents, and 12.8% ESBL-producing E. coli in effluents. In river waters, 5.6% of samples contained ESBL-producing E. coli and 1.4% (1 sample) contained VIM-producing Enterobacter cloacae complex strains. Among patients, 10.2% (39/382) carried MDR Gram-negative bacilli, of which 66.7% were ESBL-producing E. coli. In aquatic ecosystems E. coli ST131 (13.3%) and ST162 (13.3%) were the most common strains, while in humans the common were E. coli ST131 (33.3%), ST69 (11.1%) and ST410 (7.4%) in humans. The most frequent environmental antibiotic resistance genes (ARG) were bla_CTX-M-15 (24%) and bla_TEM-1B (20%), while the most common ARGs were bla_TEM-1B (20.4%), bla_CTX-M15 (18.4%) and bla_CTX-M-27 (14.3%). IncF plasmids were predominant in environmental and human strains. Conclusions: ESBL-producing E. coli and carbapenemase-producing Enterobacteriaceae are present in aquatic environments in the region. Phylogenetic similarities between environmental and clinical strains suggest a possible similar origin. Further studies are necessary to clarify transmission routes and environmental impact. Full article

Background/Objectives: Multidrug-resistant (MDR) bacterial colonization poses a significant risk for subsequent infections, especially within hospital environments. Healthcare workers can inadvertently transmit these MDR bacteria to vulnerable patients, exacerbating the problem. This study aimed to determine the colonization rates of MDR bacteria among patients and healthcare workers in a rural Ethiopian hospital with limited resources. Methods: Between 26 May and 6 June 2024, nasal, rectal, vagino-rectal exudate, and stool samples were collected from patients (n = 78) and healthcare workers (n = 11) at Gambo General Hospital (Oromia Region, Ethiopia). Samples were cultured on chromogenic media selective for methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant Enterococcus spp. (VRE), and carbapenemase-producing Enterobacteriaceae (CPE). Bacterial identification was performed using MALDI-TOF mass spectrometry (Bruker), antimicrobial susceptibility testing using the MicroScan WalkAway system (Beckman Coulter), and genotypic characterization with the MDR Direct Flow Chip kit (Vitro). Results: MRSA nasal colonization was detected in 43.3% of patients (13/30; 95% CI: 27.4–60.8%) and 27.3% of healthcare workers (3/11; 95% CI: 6.0–61.0%) (p = 0.73). Rectal (or stool) colonization by MDR bacteria was significantly higher in pediatric patients (85.0%, 17/20; 95% CI: 62.1–96.8%) than in adults (14.3%, 4/28; 95% CI: 5.7–31.5%) (p < 0.001). Notably, a high proportion of pediatric patients harbored Escherichia coli strains co-producing NDM carbapenemase and CTX-M ESBL, and VRE strains were also predominantly isolated in this group. Conclusions: This study reveals a concerningly high prevalence of MRSA and MDR Enterobacteriaceae, especially among children at Gambo Hospital. The VRE prevalence was also substantially elevated compared to other studies. These findings underscore the urgent need for strengthened infection control measures and antimicrobial stewardship programs within the hospital setting. Full article

Antimicrobial resistance (AMR) poses a growing threat to global health, and its spread through the food chain is gaining increasing attention. While AMR in food of animal origin has been extensively studied, less is known about its prevalence in plant-based foods, particularly fresh and ready-to-eat (RTE) vegetables. This study investigated the occurrence of antimicrobial-resistant bacteria in fresh and RTE vegetables. Isolates were subjected to antimicrobial susceptibility testing and molecular analyses for the characterization of antimicrobial resistance genes (ARGs). A significant proportion of samples were found to harbor antimicrobial-resistant bacteria, including multidrug-resistant strains. Several ARGs, including those encoding extended-spectrum β-lactamases (ESBLs) and resistance to critically important antimicrobials, were detected. The findings point to environmental contamination—potentially originating from wastewater reuse and agricultural practices—as a likely contributor to AMR dissemination in vegetables. The presence of antimicrobial-resistant bacteria and ARGs in fresh produce raises concerns about food safety and public health. The current regulatory framework lacks specific criteria for monitoring AMR in vegetables, highlighting the urgent need for surveillance programs and risk mitigation strategies. This study contributes to a better understanding of AMR in the plant-based food sector and supports the implementation of a One Health approach to address this issue. Full article

Objectives: Significant differences in antibiotic resistance (AR) rates and multi-drug resistant (MDR) bacteria incidence exist in patients with acute cholangitis (AC) from different countries or regions. We aim to characterize and compare the microbial spectrum and AR patterns in patients with AC from two tertiary centers in Europe. Methods: We conducted a prospective, observational, multicentric study including patients diagnosed with AC and a positive bile culture, admitted to the Colentina Clinical Hospital (CCH), Bucharest, Romania, and the Haut-Lévêque Hospital (HLH), Bordeaux, France, between April 2022 and October 2023. Results: We included a total of 144 patients from the CCH with 190 positive bile cultures (31 patients had up to five episodes of AC during the study period) and 241 identified microbial strains, and 62 patients from the HLH with 67 positive bile cultures (5 patients had two episodes of AC) and 194 identified microbial strains. The most frequently isolated bacteria were Escherichia coli (30.70%) and Pseudomonas spp. (27.80%) in the CCH group, and Enterococcus faecalis (15.46%) and Escherichia coli (22/11.34%) in the HLH group. Furthermore, 51 (21.16%) of the strains identified in the CCH group and 15 (7.21%) in the HLH group were MDR, such as extended-spectrum beta-lactamase-producing Enterobacteriaceae or carbapenemase-producing Enterobacterales. The resistance rates for common antibiotics were 13.69% in the CCH group vs. 8.76% in the HLH group for ceftriaxone, 9.54% vs. 2.06% for meropenem, 16.59% vs. 6.70% for piperacillin/tazobactam, and 25.31% vs. 7.73% for levofloxacin. Conclusions: This comparative study shows significant differences between these countries in terms of the AR rates and MDR bacteria prevalence, highlighting the role of bile cultures as a safe and cost-effective method for guiding antibiotic treatment, thereby reducing the AR rates and complications. Full article

Background: The global rise of multidrug-resistant Gram-negative bacteria, particularly non-fermenting species and carbapenemase-producing Enterobacteriaceae, poses a significant challenge to hospital infection control. Methods: In this study, a total of 89 Acinetobacter spp. isolates, 14 Pseudomonas aeruginosa, and 14 carbapenem-resistant Enterobacteriaceae isolates were collected from patients in a tertiary hospital. Whole-genome sequencing and antimicrobial susceptibility testing were conducted. Resistance mechanisms and evolutionary relationships were analyzed using phylogenetic analysis and genetic context mapping. Results: Among the non-fermenting isolates, A. baumannii exhibited high resistance to carbapenems, clustering into distinct clonal groups enriched with genes associated with biofilm formation and virulence genes. P. aeruginosa isolates harbored fewer resistance genes but carried notable mutations in the efflux pump systems and the oprD gene. In Enterobacteriaceae, four bla_NDM alleles were identified within a conservative structural sequence, while bla_KPC-2 was located in a non-Tn4401 structure flanked by IS481- and IS1182-like insertion sequences. Phylogenetic analysis revealed that bla_NDM-positive E. coli strains were closely related to susceptible lineages, indicating horizontal gene transfer. Conversely, K. pneumoniae isolates harboring bla_KPC-2 formed a tight clonal cluster, suggesting clonal expansion. Conclusions: The study reveals distinct transmission patterns between resistance genes: horizontal dissemination of bla_NDM and clonal expansion of bla_KPC-2 in K. pneumoniae. These findings emphasize the need for resistance-gene-specific genomic surveillance and infection control strategies to prevent further nosocomial dissemination. Full article

In recent years, one of the most important issues in public health is the rapid growth of antibiotic resistance among pathogens. Multidrug-resistant (MDR) strains (mainly Enterobacteriaceae and non-fermenting bacilli) cause severe infections, against which commonly used pharmaceuticals are ineffective. Therefore, there is an urgent need for new treatment options and drugs with innovative mechanisms of action. Natural compounds, especially alkaloids, are showing promising potential in this area. This review focuses on the ability of the isoquinoline alkaloid berberine (BRB) to overcome various resistance mechanisms against conventional antimicrobial agents. BRB has demonstrated significant activity in inhibiting efflux pumps of the RND (Resistance-Nodulation-Cell Division) family, such as MexAB-OprM (P. aeruginosa) and AdeABC (A. baumannii). Moreover, BRB was able to decrease quorum sensing activity in both Gram-positive and Gram-negative pathogens, resulting in reduced biofilm formation and lower bacterial virulence. Additionally, BRB has been identified as a potential inhibitor of FtsZ, a key protein responsible for bacterial cell division. Particularly noteworthy, though requiring further investigation, are reports suggesting that BRB might inhibit β-lactamase enzymes, including NDM, AmpC, and ESβL types. The pleiotropic antibacterial actions of BRB, distinct from the mechanisms of traditional antibiotics, offer hope for breaking bacterial resistance. However, more extensive studies, especially in vivo, are necessary to fully evaluate the clinical potential of BRB and determine its practical applicability in combating antibiotic-resistant infections. Full article

This study examines temporal patterns in pathogens isolated from prosthetic joint infection (PJI) cases and antimicrobial resistance patterns at a Romanian orthopedic center. We have conducted a retrospective cohort study that included 674 patients undergoing hip or knee replacement revision surgery between January 2016 and December 2023. From these, 102 confirmed PJI cases requiring surgical intervention were selected for analysis. We isolated 27 microorganisms from acute PJI cultures and 82 from chronic PJIs. Staphylococcus epidermidis (33 cases, 30.3%; 95% CI 22.0–40.3) was the predominant pathogen, with coagulase-negative Staphylococci (22 cases, 20.18%; 95% CI 0.9–41.3) and Enterobacteriaceae (13 cases, 11.9%; 95% CI 6.4–18.3) also prevalent. Methicillin resistance was identified in 43.6% of coagulase-negative staphylococci and 45.5% of Staphylococcus aureus isolates. All Gram-positive isolates remained susceptible to vancomycin, linezolid, and tigecycline. Among Gram-negative bacilli, Klebsiella oxytoca and Proteus mirabilis showed resistance to third-generation cephalosporins, with phenotypic profiles suggestive of extended-spectrum β-lactamase (ESBL) production. All Escherichia coli, Enterobacter spp., and Citrobacter freundii strains were fully susceptible to tested agents, while Pseudomonas aeruginosa exhibited reduced susceptibility to ciprofloxacin, aztreonam, and imipenem. Among the isolated strains, 47 were multidrug-resistant (MDR), with Staphylococcus aureus accounting for the highest MDR count, including methicillin resistance. The distribution of microorganism types and MDR strains remained consistent throughout the study period, with no significant association between infection type and MDR strain presence or between infection site and microorganism presence except for a strong association between MDR strains and the type of microorganism (p < 0.05). The microbial profile and resistance patterns in PJIs have remained stable over eight years. Our observations do not suggest that MDR PJIs are more commonly acute cases, contrary to what has been highlighted in previous reports. The ongoing prevalence of MDR strains underscores the importance of targeted antimicrobial treatments based on local susceptibility profiles. Full article

Poultry is U.S. consumers’ protein of choice with an annual consumption of nearly 45 kg per person. This increasing demand has required poultry producers to minimize pathogen contamination to protect public health. This study assessed Salmonella and Campylobacter incidence and loads in retail chicken from conventional (CON) and raised without antibiotics (RWA) sources, while profiling antibiotic resistance of selected isolates. A total of 170 chicken samples from two brands (A and B), including whole carcass WOG (60), parts (80), and giblets (30) were evaluated. Both pathogens were examined by culture and BAX^® system methods and confirmed isolates were identified. Aerobic bacteria count (AC), Enterobacteriaceae (EB), and lactic acid bacteria (LAB) were also tested using Petrifilms™. Selected isolates of Salmonella (22) and Campylobacter (24) were tested for antibiotic susceptibility using the Sensititre™ system. The overall respective incidence of Salmonella and Campylobacter was 36% and 35% with no difference between CON (33% and 25%) and RWA (23% and 29%), but product types differed (p < 0.05). Salmonella incidence was not different between the brands, but Campylobacter differed. Giblets had a higher incidence of both pathogens at 80% and 70%, respectively. The most and least abundant Salmonella serotypes were Infantis (60%) and Ouakam (2%), while Campylobacter jejuni was the abundant species. All the indicators differed (p < 0.05) between CON and RWA. Many isolated pathogens possessed resistance to at least one antibiotic, Salmonella (91%) and Campylobacter (38%), with multidrug resistance in 45% of CON and 36% of RWA Salmonella isolates. The highest resistance was to tetracycline and nalidixic acid for both pathogens and the lowest was to antibiotics in the macrolides class. These results highlight the need for robust microbial control at all levels, as both production practices showed notable contamination and antibiotic resistance, emphasizing the need for continued surveillance at the retail level and encouraging consumers to properly cook poultry to 165 °F. Full article

Background/Objectives: This narrative review provided a broad synthesis of recent epidemiological trends, priority resistance mechanisms, and public health implications of multidrug-resistant (MDR) bacteria. We focused on the most clinically significant MDR pathogens, regional differences in resistance, and the effectiveness of containment strategies. Our goal was to synthesize current knowledge and propose research directions. Methods: Through comprehensive analysis of epidemiological studies, surveillance reports, clinical trials, and meta-analyses, we present a detailed assessment of the evolving landscape of antimicrobial resistance across both developed and developing nations. The review encompasses data from 187 countries, analyzing over 2500 published studies and reports from major health organizations. Results: Our findings reveal a concerning 43% increase in multidrug-resistant infections globally, with particularly sharp rises in healthcare-associated infections (67% increase) and community-acquired infections (38% increase) in regions with high antibiotic misuse. The analysis specifically focuses on critical pathogens, including methicillin-resistant Staphylococcus aureus (MRSA), extended-spectrum β-lactamase-producing Enterobacteriaceae (ESBL), and carbapenem-resistant Enterobacteriaceae (CRE), documenting their prevalence, transmission patterns, and treatment outcomes. Economic impact assessments indicate annual global healthcare costs exceeding USD 100 billion due to resistant infections. The review identifies significant gaps in current surveillance systems, particularly in low- and middle-income countries, and proposes standardized approaches for monitoring and containment strategies. We evaluate the effectiveness of various antimicrobial stewardship programs, documenting success rates and implementation challenges across different healthcare settings. Conclusions: The analysis concludes with evidence-based recommendations for policy reforms, research priorities, and international collaboration frameworks necessary to address this growing global health crisis. Our findings highlighted the importance of strengthening stewardship efforts, proposing novel diagnostics and therapeutic interventions, and addressing inequities in access to care and data across different countries. Full article

Antimicrobial resistance is a growing global threat, with surveillance providing essential information to control its spread and support rational treatment strategies. Klebsiella pneumoniae, a member of the Gram-negative Enterobacteriaceae family, frequently develops resistance mechanisms. This study analyzed 195 rectal swabs from companion and stray dogs in Santiago and São Nicolau (Cape Verde) and São Tomé and Príncipe, sampled during a neutering and deworming campaign conducted by Veterinary Without Borders Portugal, to detect extended-spectrum β-lactamase (ESBL)-producing bacteria. Samples were enriched and then cultured on ChromID^® ESBL agar, and resulting isolates were identified via MALDI-TOF MS. A total of 35 K. pneumoniae isolates were identified, of which 32 were confirmed as ESBL producers. Antimicrobial susceptibility testing showed 100% resistance to aztreonam, cefotaxime, cefpodoxime, and ceftaroline, and high resistance to cefepime (93.8%), ciprofloxacin (93.8%), and trimethoprim/sulfamethoxazole (90.6%). All isolates were considered multidrug-resistant but remained susceptible to cefoxitin, imipenem, and meropenem. The genes bla_CTX-M, bla_SHV, and bla_TEM were present in 96.9%, 65.6%, and 56.3% of the isolates, respectively. DNA fingerprinting revealed seven clusters, suggesting genetic diversity and strain dissemination across locations. These findings highlight the role of dogs as vectors for antimicrobial resistance dissemination, underscoring the need for continuous surveillance in both veterinary and human medicine. Full article

This study examined epidemiological aspects of rabbit pathologies, identified bacterial strains, and assessed their antimicrobial resistance, emphasizing rabbits as potential reservoirs for zoonotic multidrug resistant (MDR) bacteria and the need for continuous monitoring and antimicrobial stewardship. Samples from rabbits were cultivated and then identified using Vitek^® 2 and MALDI-TOF. Antimicrobial susceptibility was assessed by disk diffusion testing. This study analyzed 170 individuals with various pathologies, with males (58.24%) outnumbering females (41.76%). Dental abscesses (35.29%) and respiratory infections (28.24%) were most common. Antibiotic exposure was noted in 47.06% of cases, primarily involving trimethoprim (35.56%). Of the total samples, 91.18% tested positive, revealing 200 isolates from 23 bacterial genera, with Staphylococcus spp. (31%) and Escherichia coli (12%) being most frequently identified as well as species with zoonotic potential, such as Pseudomonas aeruginosa, Staphylococcus aureus, Klebsiella pneumoniae, Proteus mirabilis, and Enterococcus faecium. Antimicrobial susceptibility testing showed high efficacy for florfenicol (75%), ciprofloxacin (74.12%), and amikacin (68.65%), while significant resistance was found for kanamycin, neomycin, and trimethoprim. Nearly 49% of strains were MDR, with Gram-positive cocci, Enterobacteriaceae, and non-Enterobacteriaceae showing varying resistance, across 18 MDR genera. In conclusion, pet rabbits are potential reservoirs of zoonotic and MDR bacterial species, posing a risk for their owners. Full article

The emergence of colistin-resistant Enterobacteriaceae in food products is a growing concern due to the potential transfer of resistance to human pathogens. This study aimed to assess the prevalence of colistin-resistant Enterobacteriaceae in raw and ready-to-eat food samples collected from two regions of Italy (Apulia and Basilicata) and to evaluate their resistance phenotypes and genetic characteristics. A total of 1000 food samples were screened, with a prevalence of 4.4% of colistin-resistant Enterobacteriaceae. The majority of the isolates belonged to Enterobacter spp. (60%), followed by Moellerella wisconsensis, Atlantibacter hermannii, Klebsiella pneumoniae, and Escherichia coli, among others. Genomic sequencing and antimicrobial susceptibility testing revealed high levels of resistance to β-lactams, with most isolates exhibiting multidrug resistance (MDR). Notably, seven isolates harbored mcr genes (mcr-1, mcr-9, and mcr-10). Additionally, in four of them were predicted the IncHI2 plasmids, known to facilitate the spread of colistin resistance. Furthermore, 56 antimicrobial resistance genes were identified, suggesting the genetic mechanisms underlying resistance to several antibiotic classes. Virulence gene analysis showed that E. coli and other isolates carried genes linked to pathogenicity, increasing the potential risk to public health. This study emphasizes the role of food as a potential reservoir for colistin-resistant bacteria and the importance of monitoring the spread of AMR genes in foodborne pathogens. Full article

The growing prevalence of antibiotic-resistant bacteria within the human microbiome has become a pressing global health crisis. While antibiotics have revolutionized medicine by significantly reducing mortality and enabling advanced medical interventions, their misuse and overuse have led to the emergence of resistant bacterial strains. Key resistance mechanisms include genetic mutations, horizontal gene transfer, and biofilm formation, with the human microbiota acting as a reservoir for antibiotic resistance genes (ARGs). Industrialization and environmental factors have exacerbated this issue, contributing to a rise in infections with multidrug-resistant (MDR) bacteria, such as methicillin-resistant Staphylococcus aureus (MRSA) and carbapenem-resistant Enterobacteriaceae. These resistant pathogens compromise the effectiveness of essential treatments like surgical prophylaxis and chemotherapy, increase healthcare costs, and prolong hospital stays. This crisis highlights the need for a global One-Health approach, particularly in regions with weak regulatory frameworks. Innovative strategies, including next-generation sequencing (NGS) technologies, offer promising avenues for mitigating resistance. Addressing this challenge requires coordinated efforts, encompassing research, policymaking, public education, and antibiotic stewardship, to safeguard current antibiotics and foster the development of new therapeutic solutions. An integrated, multidimensional strategy is essential to tackle this escalating problem and ensure the sustainability of effective antimicrobial treatments. Full article

Background/Objectives: Infections caused by multidrug-resistant (MDR)bacteria pose a significant public health threat by worsening patient outcomes, contributing to hospital outbreaks, and increasing health and economic burdens. Advanced genomic tools enhance the detection of resistance genes, virulence factors, and high-risk clones, thus improving the management of MDR infections. In the Autonomous Community of Aragon, the diversity and incidence of carbapenemase-producing Enterobacteriaceae (CPE) have increased during the last years. This study analyses CPE trends at a tertiary hospital in Spain from 2021 to 2023, aiming to optimize personalized medicine. Methods: CPE isolates were the first isolate per patient, year, species, and carbapenemase from January 2021 to December 2023. Additional metadata were collected from the laboratory’s information system. Antibiotic susceptibility testing was performed by broth microdilution. Whole-genome sequencing (WGS) was performed using Illumina short reads. De novo assembly was used to generate draft genomes in order to determine their complete taxonomic classification, resistome, plasmidome, sequence type (ST), core–genome multilocus sequence typing (cgMLST), and phylogenetic relationships using a suite of bioinformatics tools and in-house scripts. Results: Between 2021 and 2023, 0.4% out of 38,145 Enterobacteriaceae isolates were CPE. The CPE rate tripled in 2022 and doubled again in 2023. The most common species was Klebsiella pneumoniae (51.8%) and the most common carbapenemase was bla_OXA-48. WGS revealed concordant species identification and the carbapenemase distribution in detail. Resistance rates to critical antibiotics, such as carbapenems, were variable, but in most cases were above 70%. Genetic diversity was observed in WGS and phylogenetic analyses, with plasmids often mediating carbapenemase dissemination. Conclusions: The increasing rate of CPE in healthcare settings highlights a critical public health challenge, with limited treatment options. Genomic characterization is essential to understanding resistance mechanisms, aiding therapy, limiting outbreaks, and improving precision medicine. Full article