Microbiology of surgical site infections in patients with cancer: A 7-year review

Background: Health care-associated infections (HAIs) have arisen as major sources of multidrugresistant bacteria. Surgical site infections (SSIs) are the most frequent HAIs in many countries, with high antimicrobial-resistant prevalence. Methods: A 7-year retrospective review (2008-2014) of microbiologic data within a prospective surveillance program on patients with SSI at a cancer hospital in Mexico. Results: There were 23,421 surgeries performed during the study period. The SSI rate was 7.9%. Gramnegative bacilli (GNB) were found in 56.5% of samples. Escherichia coli was the most frequent microorganism (27.5%), followed by Staphylococcus aureus (16.3%). SSI caused by S aureus showed a decreasing trend (P=.04). Extended-spectrum beta-lactamase (ESBL)-producing E coli increased from 39.5% in 2008 to 72.5% in 2014 (P<.001). Fluoroquinolone resistance also increased in all members of the Enterobacteriaceae. Methicillinresistant S aureus (MRSA) was isolated in 32% of cases with no significant increase (P value is not significant). Conclusions: GNB caused most SSIs, with an increase of ESBL E coli strains. In breast and thoracic surgery, S aureus remained the most frequent isolate. MRSA remained stable throughout the study period. We observed a decreasing trend in S aureus. These findings show the differences in the microbiology of SSIs in a middle-income country and the increasing trend of ESBL enterobacteria and other multidrug-resistant organisms, such as Enterococcus faecium. (C) 2017 Association for Professionals in Infection Control and Epidemiology, Inc. Published by Elsevier Inc. All rights reserved.