Abstract:

Objective To study the molecular epidemic characteristics of hypervirulent Klebsiella pneumoniae（hvKP） in Zhanjiang，and to provide a reference for clinical rational prevention and treatment of hvKP infection. Methods A total of 175 clinical isolates of Klebsiella pneumoniae（KP） were collected. The KP isolates were classified into hvKP group（48 isolates） and classic Klebsiella pneumoniae（CKP） group（127 isolates） by string test and virulence gene determination. Polymerase chain reaction（PCR） and multilocus sequence typing（MLST） were used to analyze the capsular serotyping and ST molecular typing of hvKP isolates，and the results of drug susceptibility test and the clinical characteristic of patients with infection were compared between the 2 groups. Results K1 capsular serotype（62.50%） and ST23（58.33%） were predominant in hvKP group. The hvKP group was more sensitive to antibiotics and had a lower rate of drug resistance phenotype than those of CKP group（P<0.001）. Community infection was predominant in hvKP group（56.25%），while nosocomial infection was predominant in CKP group（61.42%）（P=0.035）. The hvKP group had a higher proportion of liver abscess，sepsis，respiratory tract infection，bloodstream infection，hepatobiliary tract infection and systemic multi-site infection than CKP group（P<0.05）. However，the CKP group had a higher proportion of patients with a history of urinary system disease and urinary tract infection than hvKP group（P<0.05）. The total white blood cell count，alanine aminotransferase and aspartate aminotransferase in hvKP group were higher than those in CKP group（P<0.05）. Conclusions K1-ST23 hvKP is the dominant epidemic isolate in Zhanjiang. The hvKP is more sensitive to antibiotics than CKP. The patients with hvKP infection are prone to systemic multi-site infection，liver abscess and sepsis，and they have high infection indicators accompanied by liver function damage.

Key words: Klebsiella pneumoniae, Hypervirulence, Multilocus sequence typing, Virulent gene, Drug resistance, Capsular serotype