Relationship of pks gene islands with virulence genes and biofilm formation in Klebsiella pneumoniae / 中华微生物学和免疫学杂志

ABSTRACT

Objective:To investigate the relationship of pks gene islands with virulence genes, capsular serotypes and biofilm formation in Klebsiella pneumoniae ( Kp). Methods:A total of 113 Kp clinical isolates were collected in the First Affiliated Hospital of Fujian Medical University and divided into two groups based on the presence of pks gene islands pks+ and pks- groups. The hypermucoviscous (HM) phenotype was detected by string test. Five virulence genes ( peg-344, rmpA, rmpA2, iucA, iroB) and six common capsular serotypes (K1, K2, K5, K20, K54, K57) were detected by polymerase chain reaction (PCR). The biofilm formation ability was measured by crystal violet staining. Results:Among the 113 Kp isolates, 46 were pks+ strains and 67 were pks- strains. The detection rate of HM phenotype was higher in the pks+ group than in the pks- group [87.0% (40/46) vs 43.3% (29/67)]. The detection rates of virulence genes ( peg-344, rmpA, rmpA2, iucA, iroB) and K1 serotype in the pks+ group were also higher than those in the pks- group ( P<0.05). The biofilm formation ability of the pks+ strains was higher than the pks- strains ( P<0.05). Conclusions:Kp strains carrying pks gene islands were likely to display a HM phenotype and mainly belonged to the K1 serotype. Most of the pks+Kp strains carried the virulence genes of peg-344, rmpA, rmpA2, iucA and iroB, and had a greater ability to form biofilms.