Purpose: To investigate the clinical and microbiological characteristics of invasive and hypervirulent Klebsiella pneumoniae  (HvKP) in a teaching hospital in Southern China.
Patients and Methods: A total of 495 non-repetitive K. pneumoniae  strains were isolated from Dongguan People’s Hospital affiliated to Southern Medical University in 2018. Multivariate analysis was performed using the patients’ clinical data to identify the risk factors for HvKP.
Results: Eighty-one isolates were HvKP (16.4%, 81/495), of which 43 (53.1%) were invasive HvKP, whereas 38 (46.9%) were non-invasive HvKP. The incidence of extended spectrum beta-lactamases (ESBLs) in HvKP and classic K. pneumoniae  (cKP) were 7.4% (6/81) and 28.0% (116/414), respectively (p< 0.05). Multivariate analysis indicated that diabetes mellitus (odds ratio [OR]=12.849, 95% confidence interval [CI]: 1.494– 110.511, P=0.020) was an independent risk factor for invasive HvKP infection. Altogether, 51.2% (22/43) of invasive HvKP infections were treated with antimicrobial therapy combined with surgical drainage, and achieved good prognosis. K1-ST23 HvKP accounted for a higher proportion of invasive infections than non-invasive infections (P< 0.05), but there was no statistical difference in the prognosis between the two groups (P> 0.05). The most prevalent virulence genes in HvKP were rmpA  98.7% (80/81), followed by rmpA2  (82.7%, 67/81), iroN  (98.7%, 80/81), and iutA  90.1% (70/81). There was no significant difference in the distribution of virulence genes between invasive HvKP and non-invasive HvKP isolates (P> 0.05).
Conclusion: Invasive HvKP infection in this study was positively associated with diabetes as independent risk factors. Antibiotic therapy combined with surgical drainage is one of the most effective treatment measures of HvKP infection. Adequate attention should be paid to HvKP infection in clinical and microbiological laboratories.
Keywords: nosocomial infection, surgical drainage, pneumonia, mortality, serotype, MLST