Bacteriological characteristics of hypervirulent Klebsiella pneumoniae rmpA gene (hvKp-rmpA)-harboring strains in the south of Iran

To provide data on the occurrence of classical K. pneumoniae (cKp) and hypervirulent Klebsiella pneumoniae (hvKp) strains harboring the gene encoding regulator of mucoid phenotype A (rmpA) and evaluated characteristics of virulence biomarkers, carbapenemase, extended-spectrum-β-lactamase (ESBL)-producing, and capsule serotypes among K. pneumoniae clinical isolates collected in the south of Iran.

A total of 400 K. pneumoniae isolates were collected. First, the K. pneumoniae isolates were screened for rmpA gene by PCR, and then they were characterized for the presence of the virulence genes (pagO, iucA, iroB, luxR), capsular serotype genes (K1, K2, K5, K20, K54, and K57), carbapenemase (blaNDM, blaIMP, blaVIM, blaKPC, blaSPM, blaOXA-48, and blaOXA-181) and ESBL (blaCTX-M, blaSHV and blaTEM) genes. For all K. pneumoniae isolates phenotypic tests include of string test and disk diffusion test were performed.

In total, 16 (4%) hvKp-rmpA+ and 384 (96%) cKp were observed. Of hvKp-rmpA+ strains, 16 (100%) were carried pagO, iroB, and luxR genes, and 13 (81.3%) strains harbored iucA gene. The most prevalent capsular type genes were K1 (62%) and K2 (19%) in hvKp-rmpA+ strains. The incidence of blaSHV gene in hvKp and cKp was 94% (15/16) and 87.5% (336/384), respectively. The cKp isolates carried blaNDM (30/384; 7.8%) gene.

Our data suggest that the incidence of hvKp was low. Also, hvKp-rmpA+ strains have less antibiotic resistance than cKp isolates. Serotypes K1 and K2, and blaSHV gene were strongly associated with hvKp-rmpA+.