Aim: This study aims to assess the changes in antimicrobial resistance among some critical and high-priority microorganisms collected previously and during the coronavirus disease 2019 (COVID-19) pandemic in Mexico. Methods: We collected antimicrobial susceptibility data for critical and high-priority microorganisms from blood, urine, respiratory samples, and from all specimens, in which the pathogen may be considered a causative agent. Data were stratified and compared for two periods: 2019 versus 2020 and second semester 2019 (prepandemic) versus the second semester 2020 (pandemic). Results: In the analysis of second semester 2019 versus the second semester 2020, in blood samples, increased resistance to oxacillin (15.2% vs. 36.9%), erythromycin (25.7% vs. 42.8%), and clindamycin (24.8% vs. 43.3%) ( p ≤ 0.01) was detected for Staphylococcus aureus , to imipenem (13% vs. 23.4%) and meropenem (11.2% vs. 21.4) ( p ≤ 0.01), for Klebsiella pneumoniae . In all specimens, increased ampicillin and tetracycline resistance was detected for Enterococcus faecium ( p ≤ 0.01). In cefepime, meropenem, levofloxacin, and gentamicin ( p ≤ 0.01), resistance was detected for Escherichia coli ; and in piperacillin-tazobactam, cefepime, imipenem, meropenem, ciprofloxacin, levofloxacin, and gentamicin ( p ≤ 0.01), resistance was detected for Pseudomonas aeruginosa . Conclusion: Antimicrobial resistance increased in Mexico during the COVID-19 pandemic. The increase in oxacillin resistance for S. aureus and carbapenem resistance for K. pneumoniae recovered from blood specimens deserves special attention. In addition, an increase in erythromycin resistance in S. aureus was detected, which may be associated with high azithromycin use. In general, for Acinetobacter baumannii and P. aeruginosa , increasing resistance rates were detected.

We aimed to assess the resistance rates of antimicrobial-resistant, in bacterial pathogens of epidemiological importance in 47 Mexican centers. In this retrospective study, we included a stratified sample of 47 centers, covering 20 Mexican states. Selected isolates considered as potential causatives of disease collected over a 6-month period were included. Laboratories employed their usual methods to perform microbiological studies. The results were deposited into a database and analyzed with the WHONET 5.6 software. In this 6-month study, a total of 22,943 strains were included. Regarding Gram-negatives, carbapenem resistance was detected in ≤ 3% in Escherichia coli, 12.5% in Klebsiella sp. and Enterobacter sp., and up to 40% in Pseudomonas aeruginosa; in the latter, the resistance rate for piperacillin-tazobactam (TZP) was as high as 19.1%. In Acinetobacter sp., resistance rates for cefepime, ciprofloxacin, meropenem, and TZP were higher than 50%. Regarding Gram-positives, methicillin resistance in Staphylococcus aureus (MRSA) was as high as 21.4%, and vancomycin (VAN) resistance reached up to 21% in Enterococcus faecium. Acinetobacter sp. presented the highest multidrug resistance (53%) followed by Klebsiella sp. (22.6%) and E. coli (19.4%). The multidrug resistance of Acinetobacter sp., Klebsiella sp. and E. coli and the carbapenem resistance in specific groups of enterobacteria deserve special attention in Mexico. Vancomycin-resistant enterococci (VRE) and MRSA are common in our hospitals. Our results present valuable information for the implementation of measures to control drug resistance.

Background: Surveillance of antimicrobial resistance (AMR) requires an international approach with national and local strategies. Our aim was to summarize a retrospective 10-year report of antibiotic resistance of gram-positive and gram-negative bacteria in Mexico. Methods: A total of 46 centers from 22 states of Mexico participated. Databases of AMR from January 2009 to December 2018 were included for most species. The 10-year period was divided into five 2-year periods. Results: For Staphylococcus aureus, a decrease in resistance in all specimens was observed for erythromycin and oxacillin ( p < 0.0001 for each). For Enterobacter spp., resistance to meropenem increased for urine specimens ( p = 0.0042). For Klebsiella spp., increased drug resistance in specimens collected from blood was observed for trimethoprim/sulfamethoxazole, gentamicin, tobramycin ( p < 0.0001 for each), meropenem ( p = 0.0014), and aztreonam ( p = 0.0030). For Acinetobacter baumannii complex, high drug resistance was detected for almost all antibiotics, including carbapenems, except for tobramycin, which showed decreased resistance for urine, respiratory, and blood isolates ( p < 0.0001 for each), and for amikacin, which showed a decrease in resistance in urine specimens ( p = 0.0002). An increase in resistance to cefepime was found for urine, respiratory, and blood specimens ( p < 0.0001 for each). For Pseudomonas aeruginosa , aztreonam resistance increased for isolates recovered from blood ( p = 0.0001). Conclusion: This laboratory-based surveillance of antibiotic resistance shows that resistance is increasing for some antibiotics in different bacterial species in Mexico and highlights the need for continuous monitoring of antibiotic resistance.

We analyzed the antimicrobial resistance (AMR) data of 6519 clinical isolates of Escherichia coli (n = 3985), Klebsiella pneumoniae (n = 775), Acinetobacter baumannii (n = 163), Pseudomonas aeruginosa (n = 781), Enterococcus faecium (n = 124), and Staphylococcus aureus (n = 691) from 43 centers in Mexico. AMR assays were performed using commercial microdilution systems (37/43) and the disk diffusion susceptibility method (6/43). The presence of carbapenemase-encoding genes was assessed using PCR. Data from centers regarding site of care, patient age, and clinical specimen were collected. According to the site of care, the highest AMR was observed in E. coli, K. pneumoniae, and P. aeruginosa isolates from ICU patients. In contrast, in A. baumannii, higher AMR was observed in isolates from hospitalized non-ICU patients. According to age group, the highest AMR was observed in the ≥60 years age group for E. coli, E. faecium, and S. aureus, and in the 19–59 years age group for A. baumannii and P. aeruginosa. According to clinical specimen type, a higher AMR was observed in E. coli, K. pneumoniae, and P. aeruginosa isolates from blood specimens. The most frequently detected carbapenemase-encoding gene in E. coli was bla_NDM (84%).

Introduction: Antimicrobial resistance surveillance plays an important role in generating information about the prevalence of resistant microorganisms. In this study, we summarize a surveillance of antimicrobial resistance and carbapenemase-encoding genes for selected pathogens in Mexican healthcare centers. Methods: Databases of identification and susceptibility results collected from January 1 to March 31, 2024, from forty-one centers were gathered and analyzed using the WHONET software. Some relevant gram-negatives and gram-positives, which were isolated from relevant clinical specimens were included. Isolates were stratified by patient´s age, clinical specimens, and site of attention, and were classified as multidrug-resistant (MDR). Clinical isolates were collected from January 1 to June 30 and were genotyped for carbapenemase-encoding genes by a polymerase chain reaction test. Results: In total, 8 708 strains were included. Escherichia coli had a higher resistance to carbapenems (p < 0.05) in the 0–17 years group and Klebsiella pneumoniae (p = 0.017), Pseudomonas aeruginosa, and Acinetobacter baumannii (p < 0.05) in the 18–59 years group. P. aeruginosa had higher resistance to ceftazidime-avibactam, ceftolozane-tazobactam, cefepime, and imipenem (p < 0.05) in the 18–59 years group. K. pneumoniae had the highest resistance to carbapenems (p < 0.05) and cefepime (p < 0.001) in clinical isolates recovered from blood. For P. aeruginosa, the highest resistance to cefepime (p = 0.012) and ceftazidime (p < 0.018) was seen in isolates from urine. For Staphylococcus aureus, a higher resistance was observed for cefoxitin in lower respiratory tract specimens (p < 0.05). E. coli had the highest resistance to carbapenems (p < 0.01), and P. aeruginosa for ceftazidime (p = 0.005), cefepime (p = 0.003), piperacillin-tazobactam (p = <0.01), IPM (p = 0.006), and meropenem (p = <0.01) in clinical isolates recovered from patients in the intensive care unit (ICU). For K. pneumoniae, the highest resistance to ertapenem was observed in clinical isolates from the ICU area (p < 0.035). Finally, 67.9% of A. baumannii and 53.8% of E. coli strains were Multidrug-resistant. Candida albicans isolated from blood had susceptibility to caspofungin 100% and 90.2% for voriconazole. Regarding E. coli non-susceptible to meropenem, 16 (59.2%) were carriers of bla_NDM, and the bla_KPC gene was detected in 2 (40%) strains of K. pneumoniae. In conclusion, carbapenem resistance was higher for E. coli in the 0–17 years group and for K. pneumoniae, P. aeruginosa, and A. baumannii in the 18–59 years group. K. pneumoniae has the highest resistance to carbapenems in blood isolates and the ICU area. E. coli and P. aeruginosa had the highest carbapenem resistance in the intensive care unit. A high multidrug resistance was observed for A. baumannii and E. coli strains. A high susceptibility to caspofungin and voriconazole was observed for Candida albicans collected from blood.