Microbiological Profile, Antimicrobial Resistance, And Clinical Correlates of Resistant Abdominal Surgical-Site Infections: A Retrospective Study

Background: Abdominal surgical-site infections (SSIs) have high morbidity, and the spread of antimicrobial resistance is becoming more complicated. The aim of this study was to assess the spectrum of microorganisms, their antimicrobial susceptibility patterns and clinical associations of resistant abdominal SSIs.

Materials and methods: The 300 patients with abdominal SSI were included in a retrospective observational study. Data regarding demographics, operation, clinical history, microbiological and outcome parameters were obtained from the medical records. Standardized laboratory methods were used to identify bacteria and test the antimicrobial susceptibility. A multivariable logistic regression model was created to assess for factors that were independently associated with antimicrobial-resistant SSI.

Results: Culture positivity was observed in 184/300 patients (61.3%) with 205 isolates, of which 82.1% were monomicrobial. Gram-negative bacilli were found in 70.2% of isolates, the most common of which were Escherichia coli 30.2% and Klebsiella pneumoniae 16.6%. E. coli was 69.4% resistant to ceftriaxone and 79.4% resistant to K. pneumoniae. The rate of meropenem resistance was 12.9% and 20.6%, respectively, and 69.2% for Acinetobacter baumannii. 32.3% of Staphylococcus aureus were methicillin resistant. Independent correlates of resistant SSI included age per 10-year increase (aOR 1.15; P=0.034), emergency surgery (aOR 1.73; P=0.035), dirty/infected wounds (aOR 2.48; P=0.004), operative duration >120 min (aOR 1.82; P=0.019), ASA III–IV status (aOR 1.69; P=0.046), recent hospitalization (aOR 2.08; P=0.036), and prior antibiotic exposure (aOR 2.71; P<0.001).

Conclusion: There was a predominance of gram-negative pathogens and significant antimicrobial resistance for abdominal SSI. A risk-stratified microbiological surveillance and culture-directed antimicrobial stewardship are recommended.

Keywords: Abdominal surgery, surgical-site infection; Escherichia coli, Klebsiella pneumonia, multidrug resistance, antimicrobial susceptibility, antimicrobial resistance.