Microbiology of Surgical Site Infections and Associated Antimicrobial Use Among Vietnamese Orthopedic and Neurosurgical Patients

Abstract

Objectives.To determine the pathogens associated with surgical site infections (SSIs) and describe patterns of antimicrobial use and resistance in orthopedic and neurosurgical patients in a large university hospital in Vietnam.Design.Prospective cohort study.Setting.Cho Ray Hospital, Ho Chi Minh City, Vietnam.Patients.All patients who had operations during a 5-week study period.Results.Of 702 surgical patients, 80 (11.4%) developed an SSI. The incidence of SSI among orthopedic patients was 15.2% (48 of 315), and among neurosurgical patients it was 8.3% (32 of 387). Postoperative bacterial cultures of samples from the surgical sites were performed for 55 (68.8%) of the 80 patients with SSI; 68 wound swab specimens and 10 cerebrospinal fluid samples were cultured. Of these 78 cultures, 60 (76.9%) were positive for a pathogen, and 15 (25%) of those 60 cultures yielded multiple pathogens. The 3 most frequently isolated pathogens were Pseudomonas aeruginosa (29.5% of isolates), Staphylococcus aureus (11.5% of isolates), and Escherichia coli (10.3% of isolates). Ninety percent of S. aureus isolates were methicillin resistant, 91% of P. aeruginosa isolates were ceftazidime resistant, and 38% of E. coli isolates were cefotaxime resistant. All but 1 of the 702 patients received antimicrobial therapy after surgery, and the median duration of antimicrobial therapy was 11 days. Commonly used antimicrobials included aminopenicillins and second- and third-generation cephalosporins. Two or, more agents were given to 634 (90%) of the patients, and most combination drug regimens (86%) included an aminoglycoside.Conclusions.Our data indicate that the incidence of SSI is high in our study population, that the main pathogens causing SSI are gram-negative bacteria and are often resistant to commonly used antimicrobials, that the use of broad-spectrum antimicrobials after surgery is widespread, and that implementation of interventions aimed at promoting appropriate and evidence-based use of antimicrobials are needed in Vietnam.