Identification and sequencing of bla CTX-M genes in clinical isolates of Klebsiella pneumoniae from Milad hospital

Klebsiella pneumoniae is one of the most important causes of nosocomial infection which has recently received much attention due to its antibiotic resistance. The aim of the present study is the identification and sequencing of blaCTX-M genes in clinical isolates of K. pneumonia isolated from Milad Hospital in Tehran.

In this descriptive cross-sectional study, first, antibiotic resistance of 100 K. pnuemoniae isolates to cephalosporins was performed by agar diffusion method; then blaCTX-M group2 and blaCTX-M group9 resistance genes were identified by PCR. Genotyping was performed based on the sequence of these genes and the dendrogram was drawn using the Mega 6 software (version 6).

According to the antibiotic sensitivity testing, the resistance to cephalosporins was between 30 and 54 percent. Overall, 5% of isolates had blaCTX-M group2 and 8% of isolates had blaCTX-M group9 as well as, the genotyping results showed that in this study bla CTX-M group2 sequence with the sequences in the global database (NCBI) had little similarity, and the blaCTX-M group9 gene sequence was similar to the bla CTX-M-14 sequence gene in E. coli.

However, the frequency of blaCTX-M genes was low in this study, but due to the ability of these genes to spread by mobile genetic elements among enterobacteriaceae, it is considered alarm in the development of drug resistance among K. pneumoniae isolates.