[Evaluation of in vitro susceptibility of hospital bacterial isolates to piperacillin and tazocin (piperacillin/tazobactam].

Due to increasing frequency of infections caused by pathogens that are resistant to beta-lactam antibiotics, combinations of such antibiotics and beta-lactamase inhibitors were introduced into therapy in last few years. Tazobactam is the most potent beta-lactamase inhibitor. The purpose of the study was to evaluate in vitro susceptibility to piperacillin and piperacillin with tazobactam of 256 isolates cultured from biological samples obtained from 203 patients. The biological materials obtained were as follows: urine (44.9%), post-operative and post-traumatic wound swabs (27.3%), BAL (12.1%), blood (6.6%), drain swabs and other (5.5%). The isolates predominantly found were Escherichia coli (22.3%), Pseudomonas aeruginosa (16.0%), Staphylococcus aureus MSSA (13.7%), Proteus mirabilis (11.7%) and other. There were 95.5% of strains found susceptible to piperacillin with tazobactam and only 4.3% resistant ones. On the other hand, piperacillin only susceptible strains were 59.4% and resistant ones in 40.6%. Great differences in susceptibility to examined antimicrobial agents were observed in Enterobacteriaceae family and Staphylococcus (MSS) genus. There were no differences in susceptibility to piperacillin and tazobactam and piperacillin alone in anaerobic Enterobacteriaceae strains and non-fermenting Gram-negative bacilli.