Correlation of Multi-drug Resistance, Integron and blaESBL Gene Carriage With Genetic Fingerprints of Extended-Spectrum β-Lactamase Producing Klebsiella pneumoniae.

BACKGROUND

Some genetic and phenotypic variables are associated among distinct microbial populations.

OBJECTIVES

The associations between multi-drug resistance (MDR) phenotypes, prevalence of antibiotic resistance integrons (ARIs), bla SHV, bla TEM and bla CTX-M gene carriage and genetic fingerprints of random amplified polymorphic DNA (RAPD), confirmed by pulsed field gel electrophoresis (PFGE), were investigated among extended-spectrum β-lactamases (ESBL)-producing nosocomial isolates of Klebsiella pneumoniae.

MATERIALS AND METHODS

Susceptibility of 35 ESBL-producing K. pneumoniae nosocomial isolates to 22 antimicrobial agents was determined. Integron carriage was detected using specific primers for intI1, intI2 and intI3 genes by PCR.

RESULTS

All isolates were resistant to piperacillin and susceptible to imipenem. MDR phenotype was observed in 91.4% of the isolates. Class 1 integrons were detected in 21 (60%) and class 2 integrons in 3 (8.57%) of the isolates. Two of the isolates carried both classes and none harbored class 3 integrons. Significant correlations were observed between resistance to aminoglycosides, fluoroquinolones and sulfonamides, and between genotype groups with carriage of ARIs, MDR phenotype and bla SHV gene carriage. ARI carriage was also significantly associated with MDR phenotype.

CONCLUSIONS

Our findings suggest the possible co-carriage of some bla SHV genes and ARIs on the same plasmids harboring the MDR genes. Possible role of integrons in dissemination of ESBL-encoding bla SHV genes among ESBL-producing K. pneumoniae nosocomial isolates may be inferred.