Background: Surgical site infections (SSI) are a common type of health care associated infections. The emergence of multidrug resistant nosocomial pathogens represents a major heath burden. This study was conducted to determine the frequency of isolation and patterns of antimicrobial resistance of nosocomial pathogens causing SSI in Zagazig University Hospitals. Methodology: Samples obtained from the infected surgical wounds were subjected to microbiological identification and antibiotic susceptibility testing. The role of extended spectrum beta lactamase (ESBL) and carbapenmases in bacterial resistance to some antibiotic were evaluated. Results: The most frequently isolated species were S. aureus (31%) followed by Klebseilla pneumoniae (22%), E. coli (15%), P. aeruginosa (11%), Coagulase negative staphylococci ( CoNs) (8%) , Proteus spp (7%) and Acinetobacter spp (6%). Methecillin resistance was detected in 38 (97 %) and 8 (80 %) S. aurues and CoNs isolates, respectively. Among Gram negative organisms, 65.8% of isolates were ESBL producers, of which 60% were Carbapenem resistant. Metallo-β-lactamase was detected in 30% of Gram negative isolates. Multi-drug resistance (MDR) was observed in 50 isolates (68.5%) where extensively drug resistance (XDR) occurred in 23 (31.5%) of Gram negative isolates. Conclusion: Most of Gram-negative isolates were MDR or XDR. Antibiotic therapy of SSI must be guided by microbiological culture and antibiotic sensitivity testing. Infection prevention and control practices need more improvement. Rationalisation of antibiotic prescription must be carried out. Post discharge surveillance of SSI needs to be considered
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