Regulator of the mucoid phenotype A gene increases the virulent ability of extended-spectrum beta-lactamase-producing serotype non-K1/K2 Klebsiella pneumonia.

Abstract

BACKGROUND:

To determine whether the presence of a capsule regulator gene [i.e., regulator of mucoid phenotype A (rmpA) gene] contributes to virulence on extended-spectrum β-lactamase-producing Klebsiella pneumoniae (ESBL-KP) with serotype non-K1/K2 strains.

METHODS:

Twenty-eight ESBL-KP and non-ESBL-KP isolates were collected from the Tri-Service General Hospital (Taipei, Taiwan). The impact of the virulent rmpA gene in different capsular polysaccharide serotypes on ESBL-KP and non-ESBL-KP isolates was studied by a neutrophil phagocytosis reaction, a serum bactericidal assay, and an animal survival model.

RESULTS:

Resistance to broad spectrum antibiotics was more prevalent in ESBL-KP strains than in non-ESBL-KP strains (p < 0.01). The ESBL-KP strains had different molecular patterns from non-ESBL-KP strains, based on pulsed-field gel electrophoresis. The frequency of serum-resistant isolates was the highest among ESBL-KP strains with rmpA (i.e., rmpA(+)) [71.4% (5/7)] than among of non-ESBL-KP rmpA(+) strains [42.8% (6/14)], ESBL-KP strains without rmpA (rmpA(-)) [33.3% (7/21)], and non-ESBL-KP rmpA(-) strains [14.2% (2/14)]. The most significant increase in neutrophil resistance occurred in the ESBL-KP rmpA(+) strains in comparison to the non-ESBL-KP rmpA(+), ESBL-KP rmpA(-), and non-ESBL-KP rmpA(-) strains (p < 0.01). The results of the animal survival model were compatible with the neutrophil phagocytosis reaction and serum bactericidal assay.

CONCLUSION:

We conclude that the pathogenic potential is greater in rmpA(+) ESBL-KP strains than in rmpA(-) ESBL-KP and non-ESBL-KP strains.

• Authors: Hsin-An Lin, Ya-Li Huang, Kao-Ming Yeh, L K Siu, Jung-Chung Lin, Feng-Yee Chang
• Journal: Journal of microbiology, immunology, and infection = Wei mian yu gan ran za zhi (J Microbiol Immunol Infect) Vol. 49 Issue 4 Pg. 494-501 (Aug 2016) ISSN: 1995-9133 [Electronic] England
• PMID: 25442871 (Publication Type: Journal Article)
• Copyright: Copyright © 2014. Published by Elsevier B.V.

Chemical References

• Anti-Bacterial Agents
• Bacterial Proteins
• RmpA protein, Klebsiella pneumoniae
• beta-Lactamases

Topics

• Animals
• Anti-Bacterial Agents (therapeutic use)
• Bacterial Capsules (genetics)
• Bacterial Proteins (genetics)
• Electrophoresis, Gel, Pulsed-Field
• Humans
• Klebsiella Infections (drug therapy)
• Klebsiella pneumoniae (drug effects, genetics, pathogenicity)
• Male
• Mice
• Mice, Inbred BALB C
• Neutrophils (immunology)
• Phagocytosis (genetics, immunology)
• Serogroup
• Taiwan
• beta-Lactamases (genetics)