Molecular Typing of Gram-Negative Bacteria Causing Seconder and Tertiary Peritonitis in Intra-abdominal Infections

Introduction: Early and effective antimicrobial treatment together with source control is life-saving in severe abdominal sepsis cases seen due to complicated surgery. In this study, we aimed to detect the antibiotic resistance patterns of gram-negative bacteria isolated as causative agents of secondary and tertiary peritonitis from patients with intra-abdominal infection in our hospital and determine the phylogenetic relationship between them.Materials and Methods: Consecutive patients hospitalised in the General Surgery Clinic and Surgical Intensive Care Unit of Cukurova University Balcali Hospital wing to clinical diagnosis of secondary and tertiary peritonitis were investigated in two different groups. While the first group included patients operated on in other hospitals, the second group included patients operated on in our hospital. Species-level identification and antibiotic resistance patterns of the isolates were carried out using the VITEK-2 automated system. The relationship between the strains was determined by the pulsed-field gel electrophoresis (PFGE) method. Results: Among the total of 32 gram-negative strains, 11 were in the first group and 21 in the second group, isolated from patients that were diagnosed with peritonitis 20 Escherichia coli, six Klebsiella pneumoniae, three Pseudomonas aeruginosa, one Proteus mirabilis, one Acinetobacter baumannii, and one Achromobacter xylosoxidans isolates have been identified. No significant clonal relationship between our isolates was observed by the PFGE method. The 75.0% of E. coli isolates and 33.3% of K. pneumoniae isolates were determined to produce extended-spectrum beta-lactamase (ESBL). However, no antimicrobial resistance was developed in our patients in the first group since their hospitalisation.Conclusion: Our study, in which the clonal relationship of gram-negative bacteria causing peritonitis was investigated for the first time in our country, was thought to be necessary to demonstrate the role of long-term molecular surveillance studies on these bacteria in the control of nosocomial infections.