Ampicillin sulbactam

The antibiotic resistance patterns of clinical isolates were assessed using the CLSI-recommended disk diffusion technique [16 ]. In this study, a range of antibiotics were used including trimethoprim-sulfamethoxazole (10 µg), ciprofloxacin (5 µg), cefepime (30 µg), ceftazidime (30 µg), piperacillin-tazobactam (10–100 µg), ampicillin-sulbactam (10 µg), gentamicin (10 µg), amikacin (30 µg), and meropenem (10 µg) (BD, USA). A. baumannii ATCC 19606 strains were used as reference strains. Also, a colistin antibiogram was performed using the MIC determination method with the Phoenix BD device.

Antibiotic resistance patterns of clinical isolates were determined using disc diffusion method according to the CLSI guidelines [22 (link)]. The following antibiotics were used: levofloxacin (5 μg), ciprofloxacin (5 μg), meropenem (10 μg), imipenem (10 μg), piperacillin-tazobactam (100-10 μg), amikacin (30 μg), gentamicin (10 μg), ampicillin sulbactam (10 μg), ceftazidime (30 μg), and cefepime (30 μg) (BD, USA). P. aeruginosa ATCC 27853 was used as reference strain.

The antimicrobial susceptibility testing was done following a previously reported method [26 (link)]. Briefly, the pure colonies obtained from blood agar were resuspended in bacterial suspensions, and were made depositing two or three medium-sized colonies (2 to 3 mm) in BBL Crystal Inoculum Broth (Becton Dickinson; Franklin Lakes, NJ, USA). The obtained inoculum was adjusted while using a Mac Farland 0.5 reading (Expected CFU/mL 1.5 × 108), and cultured in Müeller Hinton 150 × 15 mm² media BD BBL (Becton Dickinson Franklin Lakes, NJ, USA). The antibiotic discs were applied with the Sensi-Disc Designer Dispenser System. The antibiotics panel was conformed by ampicillin (10 µg), ampicillin/sulbactam (10/10 µg), mezlocillin (75 µg), carbenicillin (100 µg), piperacillin/tazobactam (100/10 µg), cefazolin (30 µg), cefaclor (30 µg), cefepime (30 µg), cefoperazone (75 µg), and cefotetan (30 µg) from Becton Dickinson (Franklin Lakes, NJ, USA), Müeller Hinton medium were incubated at 37 °C for 24 h in both aerobic and anaerobic conditions. In anaerobic conditions, the media were placed in an anaerobic jar (BD BBL™ GasPak™), with a C02 gas generators envelope (BD BBL™) and another envelope of BD BBL™ GasPak™ anaerobic indicator placed on them.