Abstract
AimThis report presents phenotypic and genetic data on the prevalence and characteristics of extended-spectrum β-lactamases (ESBLs) and representative carbapenemases-producing Gram-negative species in Mexico.Material and methodsA total of 52 centers participated, 43 hospital-based laboratories and 9 external laboratories. The distribution of antimicrobial resistance data for Escherichia coli, Klebsiella pneumoniae, Enterobacter cloacae complex, Acinetobacter baumannii complex, and Pseudomonas aeruginosa in selected clinical specimens from January 1 to March 31, 2020 was analyzed using the WHONET 5.6 platform. The following clinical isolates recovered from selected specimens were included: carbapenem-resistant Enterobacteriaceae, ESBL or carbapenem-resistant E. coli, and K. pneumoniae, carbapenem-resistant A. baumannii complex, and P. aeruginosa. Strains were genotyped to detect ESBL and/or carbapenemase-encoding genes.ResultsAmong blood isolates, A. baumannii complex showed more than 68% resistance for all antibiotics tested, and among Enterobacteria, E. cloacae complex showed higher resistance to carbapenems. A. baumannii complex showed a higher resistance pattern for respiratory specimens, with only amikacin having a resistance lower than 70%. Among K. pneumoniae isolates, blaTEM, blaSHV, and blaCTX were detected in 68.79%, 72.3%, and 91.9% of isolates, respectively. Among E. coli isolates, blaTEM, blaSHV, and blaCTX were detected in 20.8%, 4.53%, and 85.7% isolates, respectively. For both species, the most frequent genotype was blaCTX-M-15. Among Enterobacteriaceae, the most frequently detected carbapenemase-encoding gene was blaNDM-1 (81.5%), followed by blaOXA-232 (14.8%) and blaoxa-181(7.4%), in A. baumannii was blaOXA-24 (76%) and in P. aeruginosa, was blaIMP (25.3%), followed by blaGES and blaVIM (13.1% each).ConclusionOur study reports that NDM-1 is the most frequent carbapenemase-encoding gene in Mexico in Enterobacteriaceae with the circulation of the oxacillinase genes 181 and 232. KPC, in contrast to other countries in Latin America and the USA, is a rare occurrence. Additionally, a high circulation of ESBL blaCTX-M-15 exists in both E. coli and K. pneumoniae.
Highlights
The distribution of antimicrobial resistance for E. coli, K. pneumoniae, E. cloacae complex, A. baumannii complex, and P. aeruginosa was analyzed in clinical specimens such as urine, blood, and respiratory specimens
The results were scored according to the Clinical and Laboratory Standards Institute (CLSI) criteria in all laboratories [12]
The results of drug susceptibility for 8,245 strains were included for analysis, and 2,243 clinical isolates were collected at the reference laboratory
Summary
Among class A, the most reported β-lactamases are the extended-spectrum β-lactamases (ESBLs) cefotaximase (CTX-M), temoneira (TEM), and sulfhydryl variable (SHV), along with the Klebsiella pneumoniae carbapenemase (KPC) [3, 4]. Class B metallo-β-lactamases include those enzymes that confer resistance to carbapenem antibiotics as the carbapenemases the imipenem (IMP), New Delhi metallo-β-lactamase (NDM), and those encoded by vimentin (VIM) [5]. Among class D β-lactamases, the most frequently reported oxacillinases (OXA) are those encoded by blaOXA-23-like, blaOXA-24-like, and blaOXA-58-like genes in Acinetobacter baumannii and by blaOXA-48-like, especially in Enterobacteriaceae. Some research groups from Mexico have published the drug resistance rates and involved genes for some Gram-negative bacteria, including A. baumannii, Pseudomonas aeruginosa, Enterobacter cloacae, K. pneumoniae, and Escherichia coli [6,7,8,9]. Information available is limited, and nationwide studies are needed
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