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16 pages, 803 KiB  
Article
Virulence and Antibiotic Resistance of aEPEC/STEC Escherichia coli Pathotypes with Serotype Links to Shigella boydii 16 Isolated from Irrigation Water
by Yessica Enciso-Martínez, Edwin Barrios-Villa, Manuel G. Ballesteros-Monrreal, Armando Navarro-Ocaña, Dora Valencia, Gustavo A. González-Aguilar, Miguel A. Martínez-Téllez, Julián Javier Palomares-Navarro and Fernando Ayala-Zavala
Pathogens 2025, 14(6), 549; https://doi.org/10.3390/pathogens14060549 (registering DOI) - 1 Jun 2025
Abstract
Irrigation water can serve as a reservoir and transmission route for pathogenic Escherichia coli, posing a threat to food safety and public health. This study builds upon a previous survey conducted in Hermosillo, Sonora (Mexico), where 445 samples were collected from a [...] Read more.
Irrigation water can serve as a reservoir and transmission route for pathogenic Escherichia coli, posing a threat to food safety and public health. This study builds upon a previous survey conducted in Hermosillo, Sonora (Mexico), where 445 samples were collected from a local Honeydew melon farm and associated packing facilities. Among the 32 E. coli strains recovered, two strains, A34 and A51, were isolated from irrigation water and selected for further molecular characterization by PCR, due to their high pathogenic potential. Both strains were identified as hybrid aEPEC/STEC pathotypes carrying bfpA and stx1 virulence genes. Adhesion assays in HeLa cells revealed aggregative and diffuse patterns, suggesting enhanced colonization capacity. Phylogenetic analysis classified A34 within group B2 as associated with extraintestinal pathogenicity and antimicrobial resistance, while A51 was unassigned to any known phylogroup. Serotyping revealed somatic antigens shared with Shigella boydii 16, suggesting possible horizontal gene transfer or antigenic convergence. Antibiotic susceptibility testing showed resistance to multiple β-lactam antibiotics, including cephalosporins, linked to the presence of blaCTX-M-151 and blaCTX-M-9. Although no plasmid-mediated quinolone resistance genes were detected, resistance may involve efflux pumps or mutations in gyrA and parC. These findings are consistent with previous reports of E. coli adaptability in agricultural environments, suggesting potential genetic adaptability. While our data support the presence of virulence and resistance markers, further studies would be required to demonstrate mechanisms such as horizontal gene transfer or adaptive evolution. Full article
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21 pages, 1043 KiB  
Systematic Review
The Global Prevalence of Antibiotic Resistance and Shiga Toxin-Producing Escherichia coli in Chickens: A Systematic Review and Meta-Analysis (2011–2024)
by Tsepo Ramatla, Nkhebenyane Jane, Mohapi Dineo, Tawana Mpho, Motlhaoloa Tshegofatso and Ntelekwane George Khasapane
Antibiotics 2025, 14(6), 568; https://doi.org/10.3390/antibiotics14060568 (registering DOI) - 31 May 2025
Abstract
Background: Shiga toxin-producing E. coli (STEC) are important foodborne pathogens that cause serious public health consequences worldwide. This study conducted a systematic review and meta-analysis of the global prevalence of antibiotic resistance and STEC in chickens. Methods: The assessment of previous study records [...] Read more.
Background: Shiga toxin-producing E. coli (STEC) are important foodborne pathogens that cause serious public health consequences worldwide. This study conducted a systematic review and meta-analysis of the global prevalence of antibiotic resistance and STEC in chickens. Methods: The assessment of previous study records was carried out following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Heterogeneity between studies was assessed using Cochrane’s Q test and I2 test statistics based on the random effects model, and comprehensive meta-analysis (CMA) software v4.0 was used to analyse the pooled prevalence estimate (PPE) of antibiotic resistance and STEC in chickens. Results: A total of 61 studies comprising 823 STEC from 18 countries were included in this study. The overall pooled prevalence of STEC was 8.9% (95% CI: 0.620–0.126). m-PCR assay showed the highest PPE of 21.0% (95%: 0.088–0.420). stx1 had the higher PPE of 12.9% (95%: 0.081–0.199), while stx2 had a PPE of 11.8% (95%: 0.077–0.176). Furthermore, the serotype O157 had the higher PPE of 80.5% (95%: 0.520–0.940). The isolates were resistant to the following antibiotics: amoxicillin and clavulanic acid, chloramphenicol, tetracycline, ciprofloxacin, gentamycin, ampicillin, neomycin, and amoxicillin. Conclusions: These findings may assist in the prevention and control of STEC in chickens globally. To minimise the spread of STEC and antibiotic resistance, future foodborne pathogen prevention and control programmes should prioritise increasing laboratory capacity for the early identification of antibiotic resistance. Full article
(This article belongs to the Special Issue Antibiotics Resistance in Animals and the Environment, 2nd Edition)
19 pages, 11928 KiB  
Article
Paralytic Shellfish Toxins in Alaskan Butter Clams: Does Cleaning Make Them Safe to Eat?
by R. Wayne Litaker, Julie A. Matweyou, Steven R. Kibler, D. Ransom Hardison, William C. Holland and Patricia A. Tester
Toxins 2025, 17(6), 271; https://doi.org/10.3390/toxins17060271 - 28 May 2025
Viewed by 57
Abstract
Butter clams (Saxidomus gigantea) are a staple in the subsistence diets of Alaskan Native communities and are also harvested recreationally. This filter–feeding species can accumulate saxitoxins (STXs), potent neurotoxins produced by late spring and summer blooms of the microalga Alexandrium catenella [...] Read more.
Butter clams (Saxidomus gigantea) are a staple in the subsistence diets of Alaskan Native communities and are also harvested recreationally. This filter–feeding species can accumulate saxitoxins (STXs), potent neurotoxins produced by late spring and summer blooms of the microalga Alexandrium catenella. The consumption of tainted clams can cause paralytic shellfish poisoning (PSP). Traditional beliefs and early reports on the efficacy of removing clam siphons have created the impression that cleaning butter clams by removing certain tissues makes them safe to eat. However, the toxin distribution within clams can vary over time, making the practice of cleaning butter clams unreliable. This study tested the effectiveness of the cleaning methods practiced by harvesters on Kodiak Island, Alaska. Specifically, butter clams were cleaned by removing different tissues to produce samples of “edible” tissues that were tested for STX content. The results were compared to historical data from a study conducted in Southeast Alaska from 1948 to 1949. Using these data, the risk for an average–sized man and woman consuming 200 g of edible tissue was calculated. The results showed that for clams containing >200 µg STX–equivalents 100 g edible tissue−1, no cleaning method reduced the concentration of STXs in the remaining tissue below the regulatory limit. Meals containing >900 µg STX–equivalents 100 g edible tissue−1 posed a substantial risk of moderate or severe symptoms. No cleaning method assured that untested butter clams are safe to eat. Full article
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13 pages, 272 KiB  
Article
The Effect of Mitomycin C on Induction of Shiga Toxin Production in Clinical STEC Isolates
by Surangi H. Thilakarathna, Brendon Parsons and Linda Chui
Toxins 2025, 17(6), 267; https://doi.org/10.3390/toxins17060267 - 27 May 2025
Viewed by 163
Abstract
Early determination of the Shiga toxin type of Shiga toxin-producing Escherichia coli (STEC) is crucial for guiding STEC-infected patients for proper and timely treatment and patient care. Most diagnostic microbiology laboratories rely on PCR assays to detect the presence of stx1 and/or stx2 [...] Read more.
Early determination of the Shiga toxin type of Shiga toxin-producing Escherichia coli (STEC) is crucial for guiding STEC-infected patients for proper and timely treatment and patient care. Most diagnostic microbiology laboratories rely on PCR assays to detect the presence of stx1 and/or stx2 and enzymatic immunoassays (EIA) to detect the presence of the Shiga toxins 1 and/or 2 in STEC-positive stool samples. Occasionally, the stool samples test positive for STEC by PCR assays but test negative for the presence of Shiga toxins. Insufficient toxin production under laboratory conditions is the main culprit of this discordance. To test whether EIA-based STEC detection could be improved, various clinical STEC strains were treated with mitomycin C, which is a commonly used inducer of Shiga toxin production. A dose-dependent increase in Shiga toxin production, in response to mitomycin C doses of up to 500 ng/mL, was observed without any bactericidal effects. Depending on the serotype, 5–50 times more Shiga toxin 2 was produced than Shiga toxin 1. Shiga toxin production was not induced by the mitomycin C treatment in certain STEC serotypes carrying the toxin subtypes stx1a, stx2a, 2b, 2f, or 2h. This diversity in toxin production indicates that other factors may determine toxin expression in certain STEC strains, which warrant further exploration. Full article
(This article belongs to the Special Issue Multi Methods for Detecting Natural Toxins)
24 pages, 1148 KiB  
Article
In-Feed vs. In-Water Chlortetracycline Administration on the Fecal Prevalence of Virulence Genes and Pathotypes of Escherichia coli Involved in Enteric Colibacillosis in Piglets
by Ramya Kalam, Raghavendra G. Amachawadi, Xiaorong Shi, Jianfa Bai, Mina Abbasi, Mike D. Tokach and Tiruvoor G. Nagaraja
Microorganisms 2025, 13(6), 1185; https://doi.org/10.3390/microorganisms13061185 - 22 May 2025
Viewed by 268
Abstract
Colibacillosis in nursery pigs, caused by Escherichia coli (ETEC, EPEC, and STEC pathotypes), remains a major economic concern in the swine industry. This study evaluated the effects of in-feed or in-water chlortetracycline (CTC) administration on the fecal prevalence of virulence genes and pathotypes [...] Read more.
Colibacillosis in nursery pigs, caused by Escherichia coli (ETEC, EPEC, and STEC pathotypes), remains a major economic concern in the swine industry. This study evaluated the effects of in-feed or in-water chlortetracycline (CTC) administration on the fecal prevalence of virulence genes and pathotypes associated with colibacillosis. A total of 1296 weaned piglets (21 days old) were allocated to 48 pens (16 pens/treatment; 27 piglets/pen) and assigned randomly to no CTC, in-feed CTC, or in-water CTC groups. CTC was administered from days 0 to 14. Fecal samples from five piglets per pen on days 0, 14, and 28 were enriched, screened by 11-plex PCR, cultured for pathotypes, and tested for CTC susceptibility and tetracycline resistance genes. None of the 360 fecal samples or 3267 E. coli isolates were positive for bfpA or aggA. Prevalence of estB (96.9%) and astA (92.8%) was highest. ETEC was the dominant pathotype (41.2%), with astA (29%) and estB (21.9%) as predominant enterotoxin genes. CTC administration had no significant effect on fecal prevalence of virulence genes or pathotypes (p > 0.05). stx2 and STEC were detected only at day 28, all harboring stx2e. All pathotypes were CTC-resistant, with tetA as the predominant resistance gene. Full article
(This article belongs to the Special Issue Advances in Veterinary Microbiology)
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15 pages, 1501 KiB  
Article
Curcumin Reverses Antibiotic Resistance and Downregulates Shiga Toxin Expression in Enterohemorrhagic E. coli
by Martin Zermeño-Ruiz, Mirian Cobos-Vargas, Mauro Donaldo Saucedo-Plascencia, Rafael Cortés-Zárate, Leonardo Hernandez-Hernandez, Teresa Arcelia Garcia-Cobian, Teresa Estrada-Garcia and Araceli Castillo-Romero
Diseases 2025, 13(5), 154; https://doi.org/10.3390/diseases13050154 - 17 May 2025
Viewed by 235
Abstract
Background: Enterohemorrhagic Escherichia coli (EHEC) is a considerable public health concern associated with several foodborne outbreaks of bloody diarrhea (BD) and the potentially lethal hemolytic uremic syndrome (HUS), the pathophysiology of which is attributable to the Shiga toxin (Stx) produced by this bacterium. [...] Read more.
Background: Enterohemorrhagic Escherichia coli (EHEC) is a considerable public health concern associated with several foodborne outbreaks of bloody diarrhea (BD) and the potentially lethal hemolytic uremic syndrome (HUS), the pathophysiology of which is attributable to the Shiga toxin (Stx) produced by this bacterium. In most patients, supportive treatment will be sufficient; however, in some cases, antibiotic treatment may be necessary. Most antibiotics are not recommended for EHEC infection treatment, particularly those that kill the bacteria, since this triggers the release of Stx in the body, inducing or worsening HUS. Azithromycin, which prevents the release of Stx and is a weaker inducer of the SOS system, has been successfully used to reduce EHEC shedding. It is necessary to identify compounds that eliminate EHEC without inducing Stx release. The use of natural compounds such as curcumin (CUR), a polyphenol derived from turmeric, has been highlighted as an alternative bactericidal treatment approach. Objective: The objective of this study was to establish the effect of CUR and its interactions with selected antibiotics on resistant EHEC O157/H7/EDL933. Methods: Bacterial cultures were exposed to CUR at three different concentrations (110, 220, and 330 µg/mL) and 1.2% DMSO, and the antimicrobial activity of CUR was assessed by measuring the optical density at 600 nm (OD600). The synergy of CUR and the antibiotics was determined with the FIC method. RT-PCR was performed to determine the expression levels of the blaCTX-M-15, catA1, acrAB-tolC stx2A, and stx2B genes. Results: Our data indicate that CUR did not affect the growth of EHEC, but when combined with the antibiotics, it acted as a bacterial resistance breaker. Synergistic combinations of CUR and cefotaxime or chloramphenicol significantly reduced colony counts. Conclusions: Our findings support the potential of CUR as a sensitizer or in combination therapy against EHEC. Full article
(This article belongs to the Section Infectious Disease)
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18 pages, 2265 KiB  
Article
Pathogenomic Characterization of Multidrug-Resistant Escherichia coli Strains Carrying Wide Efflux-Associated and Virulence Genes from the Dairy Farm Environment in Xinjiang, China
by Muhammad Shoaib, Sehrish Gul, Sana Majeed, Zhuolin He, Baocheng Hao, Minjia Tang, Xunjing Zhang, Zhongyong Wu, Shengyi Wang and Wanxia Pu
Antibiotics 2025, 14(5), 511; https://doi.org/10.3390/antibiotics14050511 - 15 May 2025
Viewed by 274
Abstract
Background/Objectives: Livestock species, particularly dairy animals, can serve as important reservoirs of E. coli, carrying antibiotic resistance and virulence genes under constant selective pressure and their spread in the environment. In this study, we performed the pathogenomic analysis of seven multidrug [...] Read more.
Background/Objectives: Livestock species, particularly dairy animals, can serve as important reservoirs of E. coli, carrying antibiotic resistance and virulence genes under constant selective pressure and their spread in the environment. In this study, we performed the pathogenomic analysis of seven multidrug resistant (MDR) E. coli strains carrying efflux-associated and virulence genes from the dairy farm environment in Xinjiang Province, China. Methods: First, we processed the samples using standard microbiological techniques followed by species identification with MALDI-TOF MS. Then, we performed whole genome sequencing (WGS) on the Illumina NovaSeq PE150 platform and conducted pathogenomic analysis using multiple bioinformatics tools. Results: WGS analysis revealed that the E. coli strains harbored diverse antibiotic efflux-associated genes, including conferring resistance to fluoroquinolones, aminoglycosides, aminocoumarins, macrolides, peptides, phosphonic acid, nitroimidazole, tetracyclines, disinfectants/antiseptics, and multidrug resistance. The phylogenetic analysis classified seven E. coli strains into B1 (n = 4), C (n = 2), and F (n = 1) phylogroups. PathogenFinder predicted all E. coli strains as potential human pathogens belonging to distinct serotypes and carrying broad virulence genes (ranging from 12 to 27), including the Shiga toxin-producing gene (stx1, n = 1). However, we found that a few of the virulence genes were associated with prophages and genomic islands in the E. coli strains. Moreover, all E. coli strains carried a diverse bacterial secretion systems and biofilm-associated genes. Conclusions: The present study highlights the need for large-scale genomic surveillance of antibiotic-resistant bacteria in dairy farm environments to identify AMR reservoir spillover and pathogenic risks to humans and design targeted interventions to further stop their spread under a One Health framework. Full article
(This article belongs to the Special Issue Antibiotic Resistance: A One-Health Approach, 2nd Edition)
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7 pages, 374 KiB  
Communication
Occurrence of Multiple stx1 Genes and Rare Genomic Variation in stx1 Shiga Toxin-Producing Escherichia coli
by Michaela Projahn, Maria Borowiak, Matthias Contzen, Ekkehard Hiller, Christiane Werckenthin, Elisabeth Schuh and Carlus Deneke
Microorganisms 2025, 13(5), 1079; https://doi.org/10.3390/microorganisms13051079 - 6 May 2025
Viewed by 204
Abstract
Shiga toxin-producing Escherichia coli are important foodborne pathogens. There are several subtypes of the Shiga toxin Stx known, with Stx2 (a–o) being more diverse than Stx1 (a, c, d). Multiple occurrences of stx2 genes as well as combinations of stx1 and stx2 have [...] Read more.
Shiga toxin-producing Escherichia coli are important foodborne pathogens. There are several subtypes of the Shiga toxin Stx known, with Stx2 (a–o) being more diverse than Stx1 (a, c, d). Multiple occurrences of stx2 genes as well as combinations of stx1 and stx2 have been reported. However, there is a lack of knowledge on the occurrence of multiple stx1 genes in STEC strains. Here, we report two strains from food and animal feces which show genomic variations in the stx1 operon. The first strain harbors stx1a and stx1c genes, and the second strain shows an inactive stx1 operon due to an insertion in the stxA1a subunit gene. The screening of publicly available complete genome sequences of STEC revealed further strains harboring multiple stx1 genes, indicating that those strains also occur in human infections. This should be kept in mind when applying routine diagnostic methods like PCR, that do not detect multiple occurrences of stx1 genes of the same subtype. Moreover, the impact on the severity of human infections due to multiple stx1 genes has not been investigated well. Full article
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11 pages, 1028 KiB  
Article
Potential for Misinterpretation in the Laboratory Diagnosis of Clostridioides difficile Infections
by Alexandra Kalacheva, Metodi Popov, Valeri Velev, Rositsa Stoyanova, Yordanka Mitova-Mineva, Tsvetelina Velikova and Maria Pavlova
Diagnostics 2025, 15(9), 1166; https://doi.org/10.3390/diagnostics15091166 - 3 May 2025
Viewed by 313
Abstract
Background/Objective. Toxin-producing strains of Clostridioides difficile (C. diff) are the most commonly identified cause of healthcare-associated infection in the elderly. Risk factors include advanced age, hospitalization, prior or concomitant systemic antibacterial therapy, chemotherapy, and gastrointestinal surgery. Patients with unspecified and [...] Read more.
Background/Objective. Toxin-producing strains of Clostridioides difficile (C. diff) are the most commonly identified cause of healthcare-associated infection in the elderly. Risk factors include advanced age, hospitalization, prior or concomitant systemic antibacterial therapy, chemotherapy, and gastrointestinal surgery. Patients with unspecified and new-onset diarrhea with ≥3 unformed stools in 24 h are the target population for C. diff infection (CDI) testing. To present data on the risks of laboratory misdiagnosis in managing CDI. Materials. In two general hospitals, we examined 116 clinical stool specimens from hospitalized patients with acute diarrhea suspected of nosocomial or antibiotic-associated diarrhea (AAD) due to C. diff. Enzyme immunoassay (EIA) tests for the detection of C. diff toxins A (cdtA) and B (cdtB) in stool, automated CLIA assay for the detection of C. diff GDH antigen and qualitative determination of cdtA and B in human feces and anaerobic stool culture were applied for CDI laboratory diagnosis. MALDI-TOF (Bruker) was used to identify the presumptive anaerobic bacterial colonies. The following methods were used as confirmatory diagnostics: the LAMP method for the detection of Salmonella spp. and simultaneous detection of C. jejuni and C. coli, an E. coli Typing RT-PCR detection kit (ETEC, EHEC, STEC, EPEC, and EIEC), API 20E and aerobic stool culture methods. Results. A total of 40 toxigenic strains of C. diff were isolated from all 116 tested diarrheal stool samples, of which 38/40 produced toxin B and 2/40 strains were positive for both cdtA and cdtB. Of the stool samples positive for cdtA (6/50) and/or cdtB (44/50) by EIA, 33 were negative for C. diff culture but positive for the following diarrheal agents: Salmonella enterica subsp. arizonae (1/33, LAMP, culture, API 20E); C. jejuni (2/33, LAMP, culture, MALDI TOF); ETEC O142 (1/33), STEC O145 and O138 (2/33, E. coli RT-PCR detection kit, culture); C. perfringens (2/33, anaerobic culture, MALDI TOF); hypermycotic enterotoxigenic K. pneumonia (2/33) and enterotoxigenic P. mirabilis (2/33, culture; PCR encoding LT-toxin). Two of the sixty-six cdtB-positive samples (2/66) showed a similar misdiagnosis when analyzed using the CLIA method. However, the PCR analysis showed that they were cdtB-negative. In contrast, the LAMP method identified a positive result for C. jejuni in one sample, and another was STEC positive (stx1+/stx2+) by RT-PCR. We found an additional discrepancy in the CDI test results: EPEC O86 (RT-PCR eae+) was isolated from a fecal sample positive for GHA enzyme (CLIA) and negative for cdtA and cdtB (CLIA and PCR). However, the culture of C. diff was negative. These findings support the hypothesis that certain human bacterial pathogens that produce enterotoxins other than C. diff, as well as intestinal commensal microorganisms, including Klebsiella sp. and Proteus sp., contribute to false-positive EIA card tests for C. diff toxins A and B, which are the most widely used laboratory tests for CDI. Conclusions. CDI presents a significant challenge to clinical practice in terms of laboratory diagnostic management. It is recommended that toxin-only EIA tests should not be used as the sole diagnostic tool for CDI but should be limited to detecting toxins A and B. Accurate diagnosis of CDI requires a combination of laboratory diagnostic methods on which proper infection management depends. Full article
(This article belongs to the Section Diagnostic Microbiology and Infectious Disease)
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15 pages, 1948 KiB  
Article
Characterization of Seven Shiga Toxin Phages Induced from Human-Derived Shiga Toxin-Producing Escherichia coli
by Xinxia Sui, Shuyun Wang, Xi Yang, Peihua Zhang, Hui Sun, Xiangning Bai and Yanwen Xiong
Microorganisms 2025, 13(4), 783; https://doi.org/10.3390/microorganisms13040783 - 28 Mar 2025
Viewed by 378
Abstract
Shiga toxin-producing Escherichia coli (STEC) is an important pathogen that can cause asymptomatic infections, diarrhea, hemorrhagic colitis (HC), and life-threatening hemolytic uremic syndrome (HUS) in humans. Shiga toxins (Stxs) are the major virulence factors encoded by prophages, which play a crucial role in STEC [...] Read more.
Shiga toxin-producing Escherichia coli (STEC) is an important pathogen that can cause asymptomatic infections, diarrhea, hemorrhagic colitis (HC), and life-threatening hemolytic uremic syndrome (HUS) in humans. Shiga toxins (Stxs) are the major virulence factors encoded by prophages, which play a crucial role in STEC pathogenesis and evolution. In this study, seven Stx phages were obtained from STEC isolates derived from four asymptomatic food handlers, two diarrheal patients, and one outbreak-related HUS case in China. These phages exhibited three morphologies: an icosahedral head with either a short or a long tail, and an elongated head with a long tail. Of these seven phages, three were sequenced; two showed a complete identity with their respective prophage sequences, while phage phiXuzhou21-Stx2a lacked a 6011 bp region-encoding integrase, excisionase, and hypothetical proteins. Comparative genome analysis revealed that the induced seven phages primarily varied in their regulatory regions, whereas the short-tailed phages showed high similarity in their morphogenesis-related regions. In addition, five of the seven phages demonstrated the ability to convert non-pathogenic E. coli strains into Stx-producing transduced strains. Under inducing conditions, Stx expression levels were significantly increased in these transduced strains. These findings underscore the diversity and adaptability of Stx phages and emphasize the importance of understanding their genetic and molecular interactions with host bacteria. Full article
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18 pages, 3872 KiB  
Article
Prevalence, Molecular Characterization, and Antimicrobial Resistance Profile of Enterotoxigenic Escherichia coli Isolates from Pig Farms in China
by Jiajia Zhu, Zewen Liu, Siyi Wang, Ting Gao, Wei Liu, Keli Yang, Fangyan Yuan, Qiong Wu, Chang Li, Rui Guo, Yongxiang Tian and Danna Zhou
Foods 2025, 14(7), 1188; https://doi.org/10.3390/foods14071188 - 28 Mar 2025
Cited by 1 | Viewed by 393
Abstract
Enterotoxigenic Escherichia coli (ETEC) poses a critical threat to livestock health and food safety, particularly in regard to misuse of antimicrobial agents, which have accelerated the evolution of multidrug-resistant (MDR) ETEC strains, reshaping their virulence landscapes and epidemiological trajectories. In this study, 24 [...] Read more.
Enterotoxigenic Escherichia coli (ETEC) poses a critical threat to livestock health and food safety, particularly in regard to misuse of antimicrobial agents, which have accelerated the evolution of multidrug-resistant (MDR) ETEC strains, reshaping their virulence landscapes and epidemiological trajectories. In this study, 24 ETEC isolates from porcine diarrheal samples undergo genomic and phenotypic profiling, including virulence genotyping, bacterial adhesion, and antimicrobial resistance (AMR) analysis. Results show that multi-locus sequence typing (MLST) outputs (ST88, ST100) and serotypes (O9:H19, O116:H11, O149:H10) exhibited enhanced virulence, with F18ab-fimbriated strains carrying Shiga toxin genes (stx2A) demonstrating higher cytotoxicity than non-stx strains. There exists a significant negative correlation between bacterial growth rates and intestinal epithelial adhesion, with the expression of ETEC adhesion and virulence genes being growth-time-dependent. These relationships suggest evolutionary trade-offs favoring either rapid proliferation or virulence. Among these isolates, 95.8% were MDR, with alarming resistance to quinolones and aminoglycosides. Geospatial analysis identified region-specific AMR gene clusters, notably oqxB-aac(3) co-occurrence networks in 79% of ETEC isolates. These results highlight the urgent need for precision interventions, including vaccines targeting epidemic serotypes and AMR monitoring systems to disrupt resistance propagation across swine production networks. By underscoring the importance of current virulence and AMR profiles, this study provides actionable strategies to mitigate ETEC-associated threats to both animal welfare and meat safety ecosystems. Full article
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11 pages, 858 KiB  
Article
Non-Melibiose Fermentation and Tellurite Resistance by Shigatoxigenic and Enteropathogenic Escherichia coli O80:H2 from Diseased Calves: Comparison with Human Shigatoxigenic E. coli O80:H2
by Rie Ikeda, Keiji Nakamura, Nicolas Korsak, Jean-Noël Duprez, Tetsuya Hayashi, Damien Thiry and Jacques G. Mainil
Vet. Sci. 2025, 12(3), 274; https://doi.org/10.3390/vetsci12030274 - 14 Mar 2025
Viewed by 501
Abstract
Despite their prevalence in Europe, the source of contamination of humans by Attaching-Effacing Shigatoxigenic Escherichia coli (AE-STEC) O80:H2 remains unidentified. This study aimed to assess a procedure based on non-melibiose fermentation and resistance to tellurite to isolate AE-STEC and enteropathogenic (EPEC) O80:H2 from [...] Read more.
Despite their prevalence in Europe, the source of contamination of humans by Attaching-Effacing Shigatoxigenic Escherichia coli (AE-STEC) O80:H2 remains unidentified. This study aimed to assess a procedure based on non-melibiose fermentation and resistance to tellurite to isolate AE-STEC and enteropathogenic (EPEC) O80:H2 from healthy cattle. The genome sequences of 40 calf and human AE-STEC and EPEC O80:H2 were analyzed: (i) none harbored the mel operon, but the 70mel DNA sequence instead; (ii) the ter-type 1 operon was detected in 16 EPEC and stx1a or stx2a AE-STEC, while no ter-type 1 operon was detected in the remaining 24 EPEC and stx2d AE-STEC. The 21 calf AE-STEC and EPEC O80:H2 were tested phenotypically: (i) none fermented melibiose on melibiose-MacConkey agar plates; (ii) ten of the 11 ter-type 1-positive strains had Minimal Inhibitory Concentrations (MIC) ≥ 128 µg/mL to potassium tellurite; (iii) conversely, the ten ter-negative strains had MIC of two µg/mL. Accordingly, enrichment broths containing two µg/mL of potassium tellurite and inoculated with one high MIC (≥256 µg/mL) stx1a AE-STEC O80:H2 tested positive with the O80 PCR after overnight growth, but not the enrichment broths inoculated with one low MIC (two µg/mL) EPEC. Nevertheless, neither AE-STEC nor EPEC O80:H2 were recovered from 96 rectal fecal samples collected from healthy cattle at one slaughterhouse after overnight growth under the same conditions. In conclusion, this procedure may help to isolate stx1a and stx2a AE-STEC and EPEC O80:H2, but not stx2d AE-STEC that are tellurite sensitive, and new surveys using different procedures are necessary to identify their animal source, if any. Full article
(This article belongs to the Section Veterinary Microbiology, Parasitology and Immunology)
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19 pages, 2631 KiB  
Article
The Trade-Off Between Sanitizer Resistance and Virulence Genes: Genomic Insights into E. coli Adaptation
by Vinicius Silva Castro, Yuri Duarte Porto, Xianqin Yang, Carlos Adam Conte Junior, Eduardo Eustáquio de Souza Figueiredo and Kim Stanford
Antibiotics 2025, 14(3), 291; https://doi.org/10.3390/antibiotics14030291 - 11 Mar 2025
Viewed by 677
Abstract
Background: Escherichia coli is one of the most studied bacteria worldwide due to its genetic plasticity. Recently, in addition to characterizing its pathogenic potential, research has focused on understanding its resistance profile to inhibitory agents, whether these be antibiotics or sanitizers. Objectives: The [...] Read more.
Background: Escherichia coli is one of the most studied bacteria worldwide due to its genetic plasticity. Recently, in addition to characterizing its pathogenic potential, research has focused on understanding its resistance profile to inhibitory agents, whether these be antibiotics or sanitizers. Objectives: The present study aimed to investigate six of the main serogroups of foodborne infection (O26, O45, O103, O111, O121, and O157) and to understand the dynamics of heterogeneity in resistance to sanitizers derived from quaternary ammonium compounds (QACs) and peracetic acid (PAA) using whole-genome sequencing (WGS). Methods: Twenty-four E. coli strains with varied resistance profiles to QACs and PAA were analyzed by WGS using NovaSeq6000 (150 bp Paired End reads). Bioinformatic analyses included genome assembly (Shovill), annotation via Prokka, antimicrobial resistance gene identification using Abricate, and core-genome analysis using Roary. A multifactorial multiple correspondence analysis (MCA) was conducted to explore gene–sanitizer relationships. In addition, a large-scale analysis utilizing the NCBI Pathogen Detection database involved a 2 × 2 chi-square test to examine associations between the presence of qac and stx genes. Results: The isolates exhibited varying antimicrobial resistance profiles, with O45 and O157 being the most resistant serogroups. In addition, the qac gene was identified in only one strain (S22), while four other strains carried the stx gene. Through multifactorial multiple correspondence analysis, the results obtained indicated that strains harboring genes encoding Shiga toxin (stx) presented profiles that were more likely to be sensitive to QACs. To further confirm these results, we analyzed 393,216 E. coli genomes from the NCBI Pathogen Detection database. Our results revealed a significant association (p < 0.001) between the presence of qac genes and the absence of stx1, stx2, or both toxin genes. Conclusion: Our findings highlight the complexity of bacterial resistance mechanisms and suggest that non-pathogenic strains may exhibit greater tolerance to QAC sanitizer than those carrying pathogenicity genes, particularly Shiga toxin genes. Full article
(This article belongs to the Special Issue Microbial Resistance Surveillance and Management in Food Systems)
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25 pages, 2803 KiB  
Article
Cross-Sectional Study: Assessing the Presence of Stx2e-Producing E. coli Virotypes in Samples of Oral Fluid of Growers and Fatteners
by Ana Trbovc, Matevž Pušnik, Tim Šteferl, Melita Hajdinjak and Marina Štukelj
Pathogens 2025, 14(3), 261; https://doi.org/10.3390/pathogens14030261 - 6 Mar 2025
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Abstract
Edema disease is a multifactorial infectious disease caused by specific E. coli virotypes possessing fimbriae F18 and toxin Stx2e that cause significant losses in the post-weaning period. The aim of this study was to assess the presence of Stx2e-producing E. coli verotypes in [...] Read more.
Edema disease is a multifactorial infectious disease caused by specific E. coli virotypes possessing fimbriae F18 and toxin Stx2e that cause significant losses in the post-weaning period. The aim of this study was to assess the presence of Stx2e-producing E. coli verotypes in Slovenian commercial pig farms in relation to the biosecurity and technological measures undertaken by the owners. Samples of oral fluid were collected from growers and fatteners at 5–6 weeks, 7–8 weeks, 12 weeks and 14 weeks of age on 37 commercial pig farms, using the Verocheck® diagnostic kit for the real-time PCR detection of Stx2e. The results of RT-PCR and the questionnaire were statistically analyzed. The prevalence of E. coli strains producing Stx2e was 64.9%. Statistically significant association between the prevalence of Stx2e producing E. coli strains and the type of the farm and feed origin was proved. No association was found between prevalence and farm size, presence of quarantine or previous outbreaks of edema disease. None of the studied age groups showed a statistically significant dominance in prevalence compared to other age groups, which contradicts the current theoretical data. Further studies are needed to estimate the proportion of Stx2e produced by the EDEC pathotype compared to other E. coli strains. Full article
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24 pages, 6406 KiB  
Article
Lectin-Based Substrate Detection in Fabry Disease Using the Gb3-Binding Lectins StxB and LecA
by Serap Elçin-Guinot, Simon Lagies, Yoav Avi-Guy, Daniela Neugebauer, Tobias B. Huber, Christoph Schell, Bernd Kammerer and Winfried Römer
Int. J. Mol. Sci. 2025, 26(5), 2272; https://doi.org/10.3390/ijms26052272 - 4 Mar 2025
Viewed by 1181
Abstract
Fabry disease, the second most common lysosomal storage disorder, is caused by a deficiency of α-galactosidase A (α-Gal A), which leads to an accumulation of glycosphingolipids (GSL), mainly globotriaosylceramide (also known as Gb3). This aberrant GSL metabolism subsequently causes cellular dysfunction; however, the [...] Read more.
Fabry disease, the second most common lysosomal storage disorder, is caused by a deficiency of α-galactosidase A (α-Gal A), which leads to an accumulation of glycosphingolipids (GSL), mainly globotriaosylceramide (also known as Gb3). This aberrant GSL metabolism subsequently causes cellular dysfunction; however, the underlying cellular and molecular mechanisms are still unknown. There is growing evidence that damage to organelles, including lysosomes, mitochondria, and plasma membranes, is associated with substrate accumulation. Current methods for the detection of Gb3 are based on anti-Gb3 antibodies, the specificity and sensitivity of which are problematic for glycan detection. This study presents a robust method using lectins, specifically the B-subunit of Shiga toxin (StxB) from Shigella dysenteriae and LecA from Pseudomonas aeruginosa, as alternatives for Gb3 detection in Fabry fibroblasts by flow cytometry and confocal microscopy. StxB and LecA showed superior sensitivity, specificity, and consistency in different cell types compared to all anti-Gb3 antibodies used in this study. In addition, sphingolipid metabolism was analyzed in primary Fabry fibroblasts and α-Gal A knockout podocytes using targeted tandem liquid chromatography-mass spectrometry. Our findings establish lectins as a robust tool for improved diagnostics and research of Fabry disease and provide evidence of SL changes in cultured human cells, filling a knowledge gap. Full article
(This article belongs to the Section Biochemistry)
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