Genotyping and Detection of Klebsiella Pneumoniae Carbapenemase (KPC) Enzyme among Carbapenem-resistant Enterobacteriaceae Family isolated from Isfahan Hospitals

Carbapenem-resistant Enterobacteriaceae (CRE) bacteria are difficult to treat because of their high antibiotic resistance levels that can be mediated by carbapenemase enzymes such as Klebsiella Pneumoniae Carbapenemase (KPC). The purposes of this study were to determine the genetic and resistance patterns and to detect of KPC enzyme in carbapenem-resistant strains of Enterobacteriaceae isolates.

In this study, antibiotic resistant pattern and genotyping of carbapenem-resistant Enterobacteriaceae isolates and frequency of KPC enzyme were investigated. During 16 months of conducting the study (December 2016 until April 2018), strains of Escherichia coli, Enterobacter spp. and Citrobacter spp. were isolated and identified from different clinical specimens and antibiotic susceptibility test was determined. In addition, the prevalence of the KPC enzyme was determined by PCR and two phenotypic methods including Modified Hodge Test (MHT) and the combination test by boronic acid. Enterobacterial Repetitive Intergenic Consensus Polymerase Chain Reaction (ERIC-PCR) method was used for the determination of the clonal relationship of carbapenems resistant strains.

The results showed that among 520, 146 and 58 isolated of Escherichia coli, Enterobacter spp. and Citrobacter spp. effective antibiotics were carbapenems, piperacillin/tazobactam, amikacin, cefepime, fosfomycin, nitrofurantoin, and gentamicin, respectively. In addition, 12 strains (2.3%) of E. coli, 4 strains (2.7%) of Enterobacter and 4 strains (6.9%) of Citrobacter were resistant to carbapenems. The KPC investigation results showed the detection of this enzyme in 18 and 6 isolates using MHT and boronic acid methods respectively, but no producer strain was observed using PCR. The result of ERIC-PCR showed in carbapenem-resistant strains of Citrobacter, Enterobacter and Escherichia coli, 3, 4 and 9 distinct main clusters (patterns) were observed respectively. Discussion and

This study demonstrates the high antibiotic resistant prevalence and low specificity of standard phenotypic methods that were used for KPC detection in Isfahan City.