Prevalence of fimH and class I, II, and III integron-associated integrase genes among extensively drug-resistant Klebsiella pneumoniae isolates in Isfahan, Iran.

BACKGROUND

Virulent extensively drug-resistant (XDR) Klebsiella pneumoniae strains are increasingly being reported with corresponding increased global morbidity and mortality. Integrons may contribute to the dissemination of antibiotic resistance genes. The aim of this study was to detect the frequency of XDR K. pneumoniae strains carrying fimH and integrons genes in Isfahan.

METHODS

Samples were collected from the patients hospitalized in different wards of hospital and K. pneumoniae strains were identified among them by molecular identification based on a 16-23 S rDNA ITS fragment amplification. XDR strains were detected utilizing antibiotic susceptibility testing by Kirby-Bauer disk diffusion method. The frequencies of a virulence gene (fimH) and integron coding genes (intI, intII, and intIII) was determined in XDR strains by polymerase chain reaction (PCR) amplification.

RESULTS

Among 100 clinical strains of K. pneumoniae, 10 strains (10%) were XDR. XDR isolates were most frequently recovered from patients aged 60-80 years, particularly from urine samples in ICUs. All strains were resistant to most commonly used antibiotics including beta lactams, cephalosporins, nitrofurantoin, and some combination antibiotics. The genes fimH, intI, and intII were detected in 100%, 80%, and 40% of XDR strains, respectively.

CONCLUSION

The high prevalence of virulence and integron-coding genes in XDR strains of K. pneumoniae suggests a potential for the dissemination of virulence and resistance determinants in nosocomial settings; however, clinical impact studies are needed to confirm this. It seems that more research should be done on the genetic diversity of K. pneumoniae virulence and its transporting elements.