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.

Objective To investigate the epidemiological and etiological characteristics of gram-negative bacilli (GNB) isolated from patients with intra-abdominal infection (IAI). Methods The patients with abdominal infection were identified retrospectively during the period from 2011 to 2015. The clinical and microbiological data were analyzed by WHONET 5.6 and SPSS 20.0. Results A total of 478 cases of IAI [hospital-acquired (HA) 290 cases, community-acquired (CA) 188 cases] were included in this analysis. CA-IAI patients at low risk were associated with significantly better outcome, and lower acute physiology and chronic health evaluation (APACHE) Ⅱ score and sequential organ failure assessment (SOFA) score than the CA-IAI and HA-IAI patients at high risk. The most common gram-negative bacillus isolated from intra-abdominal infections was E. coli and K. pneumoniae. The prevalence of ESBLs-producing E. coli and K. pneumoniae isolates was 75.8％ and 35.8％, respectively. The E. coli isolates remained highly susceptible to amikacin, piperacillin-tazobactam, and carbapenems during the 5-year period, while the K. pneumoniae isolates showed poorer susceptibility to ampicillin-sulbactam. Conclusions The prevalence of ESBLs-producing GNB is increasing in the patients with IAI. Such isolates were resistant to commonly used antimicrobial agents, but generally susceptible to carbapenems. It is important to strengthen the monitoring of antimicrobial resistance in IAIs, and choose antimicrobial therapy rationally based on the results of antimicrobial susceptibility test.