Mostafa I. EL-Amir^1,, Asmaa Gaber R², Mohamed Yousef A², Tunis Gamal¹, Mohamed Ali El-Feky^{1, 3}

Purpose: To determine the bacteriological pattern of bacteria causing surgical site infection (SSI) in Qena University Hospitals and detection of biofilm producing organisms. Methodology: Wound swab from 114 patients with SSI were collected for identification of bacteria and detection of biofilm producing organisms by microtiter plate (MTP) method and tube method (TM). icaA and icaD genes were detected in Staphylococcus spp. by polymerase chain reaction (PCR) from extracted bacterial DNA Principal Findings:Patients mean age was 33.6 ± 12.7 years. 56.1% of the patients were enrolled to emergent surgeries. Diabetes mellitus was the most common risk factor detected in 17.5%. The highest infection rates were noticed after appendectomy, then followed by cholecystectomy (45.6% and 36.8% respectively). Most of bacteria isolated were gram-negative bacteria 67.2%. Escherichia coli was the most frequent bacteria (32.7%), followed by Klebsiella pneumonia (26.2%), Staphylococcus aureus (22.9%), Staphylococcus epidermidis (9.8%), Pseudomonas aeruginosa(5.7%), then Proteus spp (2.5%). Significant biofilm production were detected between Staphylococcus aureus and E. colispp by MTP method (P value <0.001 and 0.001 respectively). Significant difference between MTP method and TM in detection of biofilm producers (77.8% and 32.7% respectively), (P value <0.001). icaD gene was detected in 62.5% of Staphylococcus strains, While all Staphylococcus strains were negative for icaA gene. All positive strains for icaD gene were strong biofilm producer by MTP method. Conclusion: MTP was better than TM in detection of biofilm formation. icaD gene were positive in strong biofilm producer Staphylococcus by MTP method while icaA not.

surgical site infections, biofilm production, microtiter plate method, icaD gene, icaA gene