Extended-spectrum β-lactamase (ESBL)-producing E. coli has become an important global problem for the public health sector. This study aims to investigate the E. coli antimicrobial resistance profile among living food-producing animals in Tamaulipas, Mexico. A total of 200 fecal samples were collected from bovines, pigs, chickens and sheep. A total of 5.0% of the strains were phenotypically confirmed as ESBL producers. A high percentage of phenotypic antimicrobial resistance was observed against gentamicin (93.3%), tetracycline (86.6%) and streptomycin (83.3%). The gentamicin-resistant strains showed MDR, distributed among 27 resistance patterns to different antimicrobials. The antimicrobial resistance gene tet(A) was detected in 73.3% of isolates, aadA1 in 60.0% and sul2 in 43.3% of strains. The bla_CTX-M gene was found in 23.3% of strains. The virulence gene hlyA was detected in 43.3% of isolates; stx1 and stx2 were not detected in any strain. The phylotyping indicated that the isolates belonged to groups A (33.3%), B1 (16.6%), B2 (40.0%) and D (10.0%). These results show that food-producing animals might be a reservoir of ESBL-producing bacteria and may play a role in their spread.

Listeria (L.) monocytogenes is an opportunistic foodborne pathogen that causes listeriosis in humans and animals, reaching up to 30% case mortality. There are only a few reports in Mexico about the L. monocytogenes strains found in various foods. The aim of this study was to determine the prevalence of L. monocytogenes, serogroups, virulence genes, and antimicrobial resistance in different foods from Reynosa, Tamaulipas, Mexico. L. monocytogenes strains were characterized by microbiological and molecular methods. Susceptibility to 12 antibiotics was determined according to CLSI and EUCAST. A total of 300 samples of seafood, pasteurized and raw milk, cheese, beef, and chicken were collected from supermarkets and retail markets. The presence of L. monocytogenes was detected in 5.6% of the samples. Most strains belonged to serogroups 4b, 4d, and 4e (68.4%). All strains presented a minimum of four virulence genes; the most common were actA, hly, and plcB (92.1%). A high percentage of antimicrobial susceptibility was observed, with resistance only to STX-TMP (78.9%), STR (26.3%), MEM (21.0%), and E (2.6%). These results show that the foods in Reynosa, Tamaulipas, are a reservoir of L. monocytogenes and represent a potential health risk.

Background/Objectives: Antibiotic-resistant strains have been reported in aquatic ecosystems, with varying prevalence and resistance patterns by region. In Tamaulipas, Mexico, little information has been generated on this topic, making it difficult to estimate their potential risk to environmental and human health. Therefore, the objective of this study was to evaluate the presence and virulence of antibiotic-resistant strains of Pseudomonas aeruginosa in environmental water from Tamaulipas, Mexico. Methods: One hundred water samples were collected from different water bodies in Tamaulipas to identify P. aeruginosa by PCR and MALDI-TOF, virulence gene detection, antimicrobial susceptibility testing, and detection class 1 integrons. Results: In this study, 109 P. aeruginosa strains were isolated. Eight virulence genes were identified in 47.7% to 80.7% of the strains, with the rhlAB gene being the most frequent. The strains showed resistance or intermedia resistance to 10 of the 16 antibiotics tested, in a range of resistance values 0.9–66.2%. In total, 100% (109/109) were susceptible to ceftazidime (CAZ), gentamicin (GM), amikacin (AN), netilmicin (NET), tobramycin (NN) and norfloxacin (NOR), and 65.7% were resistant to ticarcillin/clavulanic acid and 53.5% to ticarcillin; the resistance to the remaining antibiotics was between 19.4% and 0.9%. The class 1 integron was not identified in any of the strains analyzed. Conclusions:P. aeruginosa in environmental waters of Tamaulipas showed potential to cause infections and low rates of resistance to most of the antibiotics tested. However, 20% were resistant to one of the most common treatments, which could pose a risk to public health.