Background: Surgical infections, accounting for approximately one quarter of all nosocomial
infections, contribute to longer hospital stays and higher medical costs. Clinical failure of antibiotic
treatment often is associated with increasing drug resistance.
Methods: Non-duplicated microbial isolates obtained at our institution from surgical patients
were identified and tested for antimicrobial susceptibility using the Sceptor system in
2001–2002 and the Phoenix system in 2003–2005. Epidemiologic data were extracted using Epicenter
and Powerlab. During selected periods, genetic and biochemical characterization was
performed by pulsed-field gel electrophoresis, colony blot hybridization, gene amplification
and sequencing, isoelectric focusing, and enzyme kinetics.
Results: The specimens were most commonly isolated from infections at surgical sites
(24.0%), the urinary tract (19.0%), and blood stream (10.6%). Isolates of Escherichia coli showed
an increasing prevalence of resistance to penicillins, third-generation cephalosporins,
ciprofloxacin, and gentamicin, whereas the prevalence of resistant Staphylococcus aureus generally
declined. Highly aggressive multi-drug-resistant (MDR) Pseudomonas aeruginosa
strains were widespread, although colistin remained effective in 100% of cases. A significant
increase was seen in infections attributable to S. epidermidis and Candida albicans. The overall
number of Enterobacteriaceae carrying extended-spectrum beta-lactamases increased continuously,
and new resistance traits emerged. It appeared that the TEM-92 determinant moved
from Enterobacteriaceae to nonfermenting gram-negative rods such as Acinetobacter baumannii.
Conclusion: The number and type of antimicrobial-resistance determinants are increasing.
