Distribution, characterization, and antibiotic resistance of hypervirulent Klebsiella pneumoniae isolates in a Chinese population with asymptomatic bacteriuria

• Published in: BMC microbiology Vol. 22; no. 1; pp. 29 - 9
• Main Authors: Li, Jun, Li, Yanbing, Tang, Mengli, Xia, Fengjun, Min, Changhang, Hu, Yongmei, Wang, Haichen, Zhang, Jingyi, Zou, Mingxiang
• Format: Journal Article
• Language: English
• Published: England BioMed Central Ltd 18.01.2022; BioMed Central; BMC
• Subjects: Adult; Animals; Antibiotic resistance; Antibiotics; Antiinfectives and antibacterials; Antimicrobial agents; Antimicrobial susceptibility; Asians; Asymptomatic; Asymptomatic bacteriuria; Asymptomatic Infections - epidemiology; Bacteremia; Bacteria in the urine; Bacterial infections; Bacteriuria; Bacteriuria - epidemiology; Biofilm formation; Biofilms; Biofilms - growth & development; Causes of; Distribution; Drug resistance; Drug resistance in microorganisms; Drug Resistance, Multiple, Bacterial; Epidemiology; Female; Genetic aspects; Genetic relationship; Hospitals; Humans; Hypervirulent K. pneumoniae; Identification and classification; Klebsiella; Klebsiella infections; Klebsiella Infections - epidemiology; Klebsiella Infections - ethnology; Klebsiella Infections - microbiology; Klebsiella Infections - urine; Klebsiella pneumoniae; Klebsiella pneumoniae - drug effects; Klebsiella pneumoniae - genetics; Klebsiella pneumoniae - pathogenicity; Larva - microbiology; Male; Medical research; Medicine, Experimental; Microbial Sensitivity Tests; Middle Aged; Minimum inhibitory concentration; Moths - microbiology; Nosocomial infection; Nosocomial infections; Phylogeny; Population; Serotypes; Survival; Urinary tract; Urinary tract diseases; Urinary tract infections; Urine; Urogenital system; Virulence; Virulence (Microbiology); Virulence Factors - genetics; Virulence-associated genes; Whole genome sequencing; Whole-genome sequencing (WGS); China; Asymptomatic bacteriuria; Antimicrobial susceptibility; Virulence-associated genes; Whole-genome sequencing (WGS); Biofilm formation; Hypervirulent K. pneumoniae
• DOI: 10.1186/s12866-021-02413-w
• ISSN: 1471-2180

Asymptomatic bacteriuria (ASB) frequently occurs among all ages and may develop into urinary tract infections (UTIs). Hypervirulent Klebsiella pneumoniae (hvKP) has become a new threat to human health. In our study, we aimed to investigate the epidemiological characteristics of hvKP in population with ASB. A total of 61 K. pneumoniae isolates were collected from 7530 urine samples between October and December 2020. The strains were sensitive to most of the antimicrobial agents tested, but a polymyxin resistant strain was found (MIC>16 μg/mL). Three serotypes were detected, including K1 (16.4%, 10/61), K5 (1.6%, 1/61) and K57 (3.2%, 2/61). Four strains (KPNY9, KPNY31, KPNY40, and KPNY42) carried a combination of two or more hypervirulent markers (peg-344, iroB, iucA, rmpA, and rmpA2), and their survival rates after Galleria mellonella infection were lower than those of the other strains (40.0 vs. 70.0%), suggesting that they were hvKP. These hvKP strains with lower biofilm forming ability than classical K. pneumoniae (0.2625 ± 0.0579 vs. 0.6686 ± 0.0661, P = 0.033) were identified as belonging to K2-ST65, K2-ST86, K57-ST592, and K2-ST5559 (a new ST type). KPNY31 (ST5559) shared a close genetic relationship with KPNY42 (ST86) and other ST86 isolates, which have been detected in both nosocomial and community-acquired infections. The hvKP with relatively weak biofilm formation was detected in a population with ASB, which was more likely to cause bacteremia and serious consequences. A novel sequence type (ST5559) hvKP derived from ST86 was found. Therefore, hvKP should be monitored in the population with ASB.