Distribution of integrons and phylogenetic groups among highly virulent serotypes of Klebsiella pneumoniae in a Chinese tertiary hospital

Abstract Objectives This study describes the distribution of integrons and phylogenetic groups among clinical highly virulent serotypes (HVS) Klebsiella pneumoniae isolates in a Chinese tertiary hospital. Methods Class 1, 2, and 3 integrases were identified by polymerase chain reaction (PCR) among 90 clinical isolates of HVS Klebsiella pneumoniae. Antibiotic susceptibilities were examined by the disk diffusion method. MLST and PFGE were used to analyze the genotypes of these HVS Klebsiella pneumoniae isolates. Results Serotypes K1, K2, K20, K54, K57 accounted for 54.5%, 21.1%, 1.1%, 18.9%, and 4.4% of the 90 isolates tested in this study. Among the 50 integron-positive isolates, 48(96%) and 2(4%) were classified as class 1(intI 1) an 2(intI 2) integrons, respectively. Gene cassettes encoding resistance to trimethoprim(dfr) and aminoglycosides(aac, aad) were found to be predominant in class 1 integrons. In additions, the most prevalent ST in HVS K.pneumoniae isolates was ST23 (49/90, 54.5%), followed by ST29 (11/90, 12.2%), ST86 (10/90, 11.1%), ST65(9/90, 10%), ST15(6/90, 6.7%), ST412(4/90, 4.4%), and ST34(1/90, 1.1%). Conclusion In summary, we found a high prevalence of integrons (55.6%) among highly virulent serotypes Klebsiella pneumoniae isolates in a tertiary hospital. Class 1 integrons were the most predominant and their variable regions were polymorphic in our area. The presence of integrons in HVS K.pneumoniae isolates resulted in increased antimicrobial resistance.