Microbial Uropathogens and Their Antibiotic Resistance Profile from Hospitalized Patients in Central Alabama

Abstract

Urinary tract infections remain a common problem in inpatient care. They are highly challenging to provide effective initial therapy without sensitivity data. The purpose of this study was to survey the uropathogens and their sensitivity profile at a hospital in Central Alabama and to guide experiential antibiotic selection. This was the first reported study on bacterial uropathogens and their antibiotic resistance profile at this Central Alabama hospital. The survey period was between July 2009 and June 2010, a total of 473 urine cultures were reviewed and susceptibility testing was determined using the Clinical and Laboratory Standards Institute (CLSI) microdilution method. The results indicated that Escherichia coli (45.5%) was the most common organism, followed by Klebsiella pneumoniae (18.2%), Pseudomonas aeruginosa (10.1%), Proteus mirabilis (7.8%), Enterobacter cloacae (4.2%), methicillin-resistant Staphylococcus aureus (3.0%), Klebsiella oxytoca and Citrobacter freundii (1.5%), Morganella morganii (1.3%), and the other species (7.0%). For the 215 E. coli isolates, imipenem and cephalosporins (except for cefazolin) had the highest sensitivity (99-100%, P<0.05). In contrast, ampicillin had the highest resistance (57%, P<0.05) as compared to other antibiotics (about 30%) including ampicillin/sulbactam, ciprofloxacin, levofloxacin, tetracycline, and trimethoprim/sulfamethoxazole. The major finding of this study was that ciprofloxacin, levofloxacin and trimethoprim/sulfamethoxazole had comparable sensitivity patterns for Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, and Enterobacter cloacae, the most common uropathogens at this Central Alabama hospital. Additionally, this study found that E. coli had a resistant rate of 31% to ciprofloxacin and levofloxacin compared to the resistance rate of 28.4% and 15.8% in earlier reports (Lee et al. 2010; Rattanaumpawan et al. 2010), likely indicating the continuing evolution of resistance due to antibiotic exposure. It is imperative to monitor the resistance of P. aeruginosa considering their high resistance to imipenem found in this study.

ABBREVIATIONS

UTI-urinary tract infection, TMP/SXM-trimethoprim/sulfamethoxazole, Pip/Tazo-piperacillin/tazobactam, CLSI-Clinical and Laboratory Standards Institute, E. coli-Escherichia coli, P. aeruginosa-Pseudomonas aeruginosa, K. pneumonia-Klebsiella pneumoniae, P. mirabilis-Proteus mirabilis, E. cloacae-Enterobacter cloacae, MIC-minimum inhibitory concentration, IDSA-Infectious Disease Society of America, ESBL-extended spectrum beta-lactamase.