Objective: In our hospital cefazolin is started before surgery in our hospital for prophylaxis of surgical wound infections. If wound infection develops then empirically teicoplanin or vancomycin for gram positive, and; piperacillin-tazobactam for gram negative bacteria are initiated. Antimicrobial therapy is readjusted according to the results of culture and antimicrobial susceptibility testing (AST). In this study the data were analyzed in order to guide the choice of drug for empirical therapy and after the results of AST were available.

Material and Methods: The wound culture materials sent to the microbiology laboratory between December 1st, 2014 and December 31st, 2015 were examined by direct Gram staining and inoculated onto EMB and 5% sheep blood agar media. After incubation, based on bacterial growth, microscopy results and- in case of need-direct communication with the clinics, agents decided to be a pathogen were identified and AST was performedusing Phoenix automated systems (BD Diagnostic Systems, USA), disk diffusion and gradient test (Liofilchem, Italy). AST was performed and reported according to the criteria of “European Committee on Antimicrobial Susceptibility Testing Standards” (EUCAST), and “Clinical Laboratory Standards Institute” (CLSI) cut-off points were used when needed.

Results: In total 91 strains were isolated from policlinics (n=23), clinics (n=44), and intensive care units (24). Fifty Enterobacteriaceae (23 Escherichia coli), 29 non-fermenters (18 Acinetobacter spp.), 25 Staphylococcus spp. (17 Staphylococcus aureus), 5 Streptococcus spp. and two Enterococcus spp. were isolated. The most effective antimicrobials were amikacin (100% susceptible), carbapenems (90%), colistin (100%), amikacin (100%) and piperacillin-tazobactam (90%); trimethoprim-sulphametoxazole (100%), vancomycin (100%), teicoplanin (100%), linezolid (100%), daptomycin (100%), clindamycin (94%) and topical fusidic acid (92%).

Conclusion: According to our data, we think that it would be suitable to start therapy as follows: colistin for gram negative cocci of Acinetobacter spp; amikacin or carbapenems for bacilli; topical fusidic acid, systemic trimethoprim/sulfamethoxazole or clindamycin for gram positive cocci. The empirical treatment policy in our hospital for gram negatives need to be changed since priority is recommended to be given to group A drugs which were found to be highly effective for gram positives. After pathogenic bacteria are identified,, empirical treatment may be continued or stopped according to the gram staining characteristics of bacteria. After AST results are available it will be appropriate to switch to effective group A antibiotics, if they are not effective then group B antibiotics should be chosen. Group C antibiotics should be avoided unless necessary.