Résumé
Objective:To investigate the distribution characteristics of virulence-related phenotypes/genotype, capsular serotype, drug resistance phenotypes, and sequence typing (ST) of Klebsiella pneumoniae in patients living in Zhongjiang county, improve clinical understanding, and provide evidence for the prevention and control of bacterial drug resistance and clinical rational drug use. Methods:The data of 135 strains of Klebsiella pneumoniae isolated from patients who received treatment in Zhongjiang County People's Hospital from July to December 2019 were retrospectively analyzed. Bacterial identification and drug sensitivity testing were performed using the WalkAway-40Plus automated microbiology system. Strains with a high viscosity phenotype were identified using wire drawing experiments. Hypervirulence-associated capsular serotype and virulence genes were verified by polymerase chain reaction. ST of Klebsiella pneumoniae strain was identified using multilocus sequence typing. Results:Strains with a high viscosity phenotype were identified in 50.4% of the 135 strains. 54.1%, 54.8%, and 54.1% of the strains were positive for virulence genes iucA, iroN, rmpA. The proportion of strains with capsular Serotype K1 or K2 was 11.9% and 15.6%, respectively. A total of 65 kinds of ST were identified, with ST23 and ST37 being the most common, accounting for 11.1% and 6.7%, respectively. The resistance rate of the strains to 16 kinds of antibiotics was 0.0%-25.2%, and the resistance rate to Carbapenem antibiotics, Amikacin, and Tigecycline was less than 1%. The positive rate of virulence gene of strains with a high viscosity phenotype was significantly higher than that of strains without a high viscosity phenotype ( P < 0.001), and its resistance rate to Cephalosporin was significantly lower in strains with a high viscosity phenotype than that in strains without a high viscosity phenotype ( P < 0.001). Conclusion:Klebsiella pneumoniae in Zhongjiang County is characterized by "high virulence and low drug resistance". It is necessary to continuously monitor the changes in the virulence and drug resistance of Klebsiella pneumoniae in Zhongjiang County, Sichuan Province, and be alert to the rapid dissemination of highly virulent strains.
Résumé
Objective To describe the clinical characteristics of hypervirulent Klebsiella pneumoniae (hvKP) infection.To analyze the antibiotic susceptibility of hvKP to provide the empiric antibiotic options.To investigate capsule serotype and sequence type (ST) of hvKP and their correlation with clinical profiles.Methods hvKP was defined as bacteria isolated from patients with community-acquired pyogenic liver abscess (CA-PLA) with co-infection sites outside liver or a bloodstream infection in a host without underlying biliary tract diseases.Patients with CA-PLA hospitalized in the First Hospital of China Medical University were retrospectively analyzed from January 2011 to December 2017.Antibiotic susceptibility was detected by automatic bacterial identification and antibiotic susceptibility analysis system in vitro.Polymerase chain reaction method and gene sequencing were used to detect the main capsule serotype and ST.Results A total of 140 cases with hvKP infection were enrolled.The co-infections outside liver abscess included 98 bloodstream infections,53 pneumonia,11 perianal abscess,10 urinary system infections,3 subphrenic abscess,3 endophthalmitis,2 spleen abscess,and other miscellaneous infections including 1 peritonitis,1 skin and soft tissue infection,1 myelitis,1 colitis,1 psoas major abscess and 1 myocardial abscess.Among the 140 cases,106 presented with single co-infection site,32 with 2 sites,and 2 with 3 sites.HvKP manifested high antibiotic susceptibility up to 80％ for most commonly used antibiotics.Capsule serotyping of 4,3 revived isolates indicated that K1 serotype accounted for 53.49％ (23/43),K2 34.88 (15/43),K54 2.33％ (1/43),K57 2.33％ (1/43),and other serotypes 6.98％(3/43).There was no significant distribution among K1,K2,K54,and K57 of hvKP capsule serotypes in patients with or without diabetes mellitus (P＞0.05).Multilocus sequence typing (MLST) suggested that ST23 and ST65 were predominant accounting for 39.53％ (17/4.3) and 25.58％ (11/4.3) respectively.No serotype or ST predominance was seen in any of the clinical infections.Conclusion HvKP is related to a wide spectrum of infectious diseases,including multiple extrahepatic sites and bloodstream infections besides CA-PLA with high antibiotic susceptibility.K1 and K2 are the predominant capsule serotypes,and ST 23 and ST65 are the predominant sequence types.