Frequency and diversity of CTX-M enzymes among extended-spectrum beta-lactamase-producing Enterobacteriaceae isolates from Caracas, Venezuela.
CTX-M-type extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae have been previously reported in Venezuela. We assessed the frequency and diversity of CTX-M enzymes among 97 ESBL-producing Enterobacteriaceae isolates as well as to establish the genetic relationship among CTX-M producers collected from six hospitals in Caracas. Polymerase chain reaction (PCR) assays identified the bla(CTX-M) genes in 42 isolates (43.3%). The bla(CTX-M-1) group was the most common in Escherichia coli (91 %) and the bla(CTX-M-2) in Klebsiella pneumoniae (56.6%). Presence of bla(CTX-M-1), bla(CTX-M-2), bla(CTX-M-15), and bla(CTX-M-14) was revealed by sequencing analysis. The CTX-M producers were mainly isolated from urine samples (46%). Antimicrobial susceptibility tests showed that a high proportion of CTX-M-producing isolates was resistant to ciprofloxacin and trimethoprim-sulfamethoxazole. Analysis of enterobacterial repetitive intergenic consensus PCR and repetitive extragenic palindromic PCR profiles revealed several genetic clusters between isolates carrying the bla(CTX-M-1) group, while complete genotypic diversity among isolates carrying the bla(CTX-M-2) group was observed. This study documented that CTX-M has achieved a citywide distribution, with the CTX-M-1 group as the most frequent (66.7%). The CTX-M clusters detected suggest that patient-patient transmission may have played an important role in the widespread and high prevalence of the CTX-M-1 group. To our knowledge, this is the first report of the CTX-M-15 in Venezuela.
Laboratorio de Biologia de Plasmidos, Facultad de Ciencias, Instituto Biologia Experimental, Universidad Central de Venezuela, Caracas, Venezuela. cfrm1979@yahoo.es
Carlos
C
Redondo
Adriana
A
Chalbaud
Guillermina
G
Alonso
D000900:Anti-Bacterial Agents / Q000494:pharmacology; D002939:Ciprofloxacin / Q000494:pharmacology; D024901:Drug Resistance, Multiple, Bacterial; D004755:Enterobacteriaceae / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics / Q000302:isolation & purification; D004756:Enterobacteriaceae Infections / Q000382:microbiology*; D005838:Genotype; D006801:Humans; D008826:Microbial Sensitivity Tests; D015662:Trimethoprim, Sulfamethoxazole Drug Combination / Q000494:pharmacology; D014687:Venezuela; D001618:beta-Lactamases / Q000235:genetics* / Q000378:metabolism
D000900:Anti-Bacterial Agents; D002939:Ciprofloxacin; D015662:Trimethoprim, Sulfamethoxazole Drug Combination; C473109:beta-lactamase CTX-M-15; C055184:beta-lactamase TEM-3; D001618:beta-Lactamases