Detection of CMY-type beta-lactamases in Escherichia coli isolates from paediatric patients in a tertiary care hospital in Mexico

Abstract

Background The aim of this study was to detect CMY-type beta-lactamases in E. coli isolates obtained from paediatric patients. Methods In total, 404 infection-causing E. coli isolates resistant to third and fourth generation cephalosporins (3GC, 4GC) were collected from paediatric patients over a 2 years period. The identification and susceptibility profiles were determined with an automated microbiology system. Typing of blaCMY and other beta-lactamase genes (blaTEM, blaSHV, blaCTX-M, blaVIM, blaIMP, blaKPC, blaNDM, blaOXA and blaGES) was realized by PCR and sequencing. Phenotypic detection of AmpC-type enzymes was performed using boronic acid (20 mg/mL) and cloxacillin (20 mg/mL) as inhibitors, and the production of extended-spectrum beta-lactamases was determined with the double-disk diffusion test with cefotaxime (CTX) and ceftazidime (CAZ) discs alone and in combination with clavulanic acid. The CarbaNP test and modified carbapenem inhibition method (mCIM) were used for isolates with decreased susceptibility to carbapenems. The clonal origin of the isolates was established by pulsed-field gel electrophoresis (PFGE), phylotyping method and multilocus sequence typing. Results CMY-type beta-lactamases were detected in 18 isolates (4.5%). The allelic variants found were CMY-2 (n = 14) and CMY-42 (n = 4). Of the E. coli strains with CMY, the AmpC phenotypic production test was positive in 11 isolates with cloxacillin and in 15 with boronic acid. ESBL production was detected in 13 isolates. Coexistence with other beta-lactamases was observed such as CTX-M-15 ESBL and original spectrum beta-lactamases TEM-1 and TEM-190. In one isolate, the CarbaNP test was negative, the mCIM was positive, and OXA-48 carbapenemase was detected. Phylogroup A was the most frequent (n = 9) followed by B2, E and F (n = 2, respectively), and through PFGE, no clonal relationship was observed. Eleven different sequence types (ST) were found, with ST10 high-risk clone being the most frequent (n = 4). Seventy-two percent of the isolates were from health care-associated infections; the mortality rate was 11.1%. Conclusions This is the first report in Mexico of E. coli producing CMY isolated from paediatric patients, demonstrating a frequency of 4.5%. In addition, this is the first finding of E. coli ST10 with CMY-2 and OXA-48.

A Descriptive Analysis of Urinary ESBL-Producing-Escherichia coli in Cerdanya Hospital

“…Additionally, we observed a high diversity of E. coli isolates circulating at the Cerdanya Hospital according to MLST and phylogenetic analysis, as well as the presence of the high-risk clones ST131, ST405, and ST10 [ 7 , 52 ]. Similar to previous reports from Tanzania [ 32 ] and Spain [ 53 ], the most common clonal complexes were ST10 and ST131, both carriers of CTX-M-14 and CTX-M-15 as the main ESBLs.…”

High prevalence of β-lactam and fluoroquinolone resistance in various phylotypes of Escherichia coli isolates from urinary tract infections in Jiroft city, Iran

“…Previous studies show that bla SHV is responsible for resistance to penicillins such as ampicillin and piperacillin [ 42 ]. bla CMY is a type of AmpC plasmid that may cause antibiotic resistance to ceftazidime, cefotaxime, cefoxitin, azetronam and probably cefepime [ 43 ].…”

The biogenesis of β-lactamase enzymes

“…The most commonly discussed β-lactamases from this class are the AmpC enzymes from Enterobacteriaceae, sometimes also named EC enzymes [41]. Other class C β-lactamases are also widely disseminated across the chromosomes of bacterial pathogens such as Citrobacter freundii (CMY enzymes [42,43]) or Acinetobacter baumannii (ADC enzymes [44]), and have been found on plasmids harboured by K. pneumoniae (ACT-1 [45,46]) or Salmonella enteritidis (DHA-1 [47][48][49][50]) (Table 1). Their three-dimensional structures are similar to class A enzymes (Fig.…”