Epidemiological and clinical infection features of heterogeneous vancomycin-intermediate Staphylococcus aureus / 中国感染与化疗杂志

ABSTRACT

Objective To investigate the prevalence and clinical characteristics of heterogeneous vancomycin-intermediate Staphylococcus aureus (hVISA) in the First Affiliated Hospital of Chongqing Medical University. Methods Clinical isolates of S. aureus were collected from the hospital during the period from 2012 to 2015 and were tested for susceptibility to vancomycin using agar dilution method. The results were interpreted according to CLSI 2016 breakpoints. VISA and hVISA strains were screened out by population analysis profile-area under the curve (PAP-AUC). E-test was carried out to determine the MIC of VISA. The clinical data of the patients infected with S. aureus were reviewed retrospectively. Results A total of 105 patients were included in this analysis. And 105 strains of S. aureus were isolated from these patients, including methicillin-resistant S. aureus (MRSA) strains (58.1％, 61/105). PAP-AUC identified 19 (18.1％) hVISA strains and 10 (9.5％) VISA strains. Overall, 52 of the 105 patients were nosocomial infections and 53 community infections. The prevalence of MRSA was 69.2％ (36/52) in nosocomial infections, higher than that in community infections (47.2％, 25/53) (P＜0.05). The prevalence of hVISA in community infections (20.8％, 11/53) did not show significant difference from that in nosocomial infections (15.4％, 8/52) (P＞0.05). The clinical outcome (P＞0.05) and length of hospital stay (P＞0.05) did not show significant difference between hVISA and non-hVISA infections, or between VISA and non-VISA infections. Conclusions The prevalence of hVISA is high in this hospital, which does not show difference between S. aureus nosocomial infection and community infection, or between MRSA and MSSA. The length of hospital stay of hVISA infection is not significantly longer than that of nonhVISA infection. The clinical outcome of hVISA infection does not show difference from that of non-hVISA infection. Larger sample size is required to better understand the prevalence and clinical features of hVISA.