Prevalence of multidrug-resistant bacteria at a tertiary-care teaching hospital in Mexico: special focus on Acinetobacter baumannii.

Our aim was to determine the prevalence of multidrug resistance of Acinetobacter baumannii and other pathogens at a tertiary-care teaching hospital in Mexico over a 3-year period. Clinical isolates of A. baumannii (n = 550), Pseudomonas aeruginosa (n = 250), some Enterobacteriaceae species (n = 500) and Staphylococcus aureus (n = 250) collected over a 3-year period were included. Susceptibility tests were performed by the broth microdilution method. 74% of A. baumannii, 40% of Escherichia coli, 34% of P. aeruginosa, 22% of Klebsiella pneumoniae, 9% of Enterobacter cloacae, and 7% of Serratia sp. were multidrug resistant. 59% of A. baumannii clinical isolates were meropenem-resistant. A. baumannii isolates from the lower respiratory tract were the most susceptible, followed by urine clinical isolates. Species from Enterobacteriaceae showed susceptibility rates higher than 90% to meropenem and tigecycline and Serratia sp. showed the highest susceptibility to the drugs evaluated. For P. aeruginosa, the most potent drug was levofloxacin, followed by meropenem and piperacillin-tazobactam. With regard to S. aureus, 96% of the isolates were susceptible to vancomycin, followed by tigecycline and minocycline (91% of strains susceptible). The high multidrug resistance observed underscores the need for surveillance of bacterial drug resistance.