Colonization and Resistance Patterns of Gram-Positive and Gram-Negative Bacteria in Patients Had No Recent History of Hospitalization

Abstract

Objectives: The aims of this study were to evaluate colonization with resistant gram-positive and gram-negative microorganisms and the results of antibiotic susceptibility of patients who had no history of hospitalization at least within the last 3 months and also to evaluate the risk factors of antibiotic resistance in bacterial isolates. Methods: A cross-sectional study was designed in a university hospital. Patients admitted to hospital between January 1, and December 31, 2008, was included in the study. A total of 653 isolates of nasal and rectal swab cultures were obtained from 248 patients. Risk factors and demographic data were determined with a prospective surveillance. Logistic regression models were performed to evaluate the independent risk factors for resistance. Results: Methicillin resistant Staphylococcus aureus rate in Staphylococcus aureus was 3.9%, and methicillin resistance rate in coagulasenegative staphylococci was 60.6%. Extended-spectrum A-lactamase (ESBL) production rate of Escherichia coli and Klebsiella pneumoniae isolates was 15%, quinolone resistance rate in Enterobactericeae was 20.7%, and vancomycin resistance rate in Enterococcus species was 10.8%. Univariate analyses were shown that antibiotic use was found to be risk factors associated with the recovery of a resistant organism for ESBL production (odds ratio [OR], 6.2; 95% confidence interval [CI], 2.8Y13.8), quinolone (OR, 3.5; 95% CI, 1.9Y6.6), and methicillin resistance (OR, 3.3; 95% CI, 1.7Y6.2). In multivariate analysis, independent risk factors associated with the recovery of a resistant organism were found to be use of antibiotics. Previous hospitalization was also found to be an independent risk factor for methicillin resistance (OR, 2.4; 95% CI, 1.2Y4.6). Conclusions: Resistance rates of isolates were found to be high. An especially high rate of quinolone resistance and production of ESBL in colonized Enterobacteriacea species and vancomycin resistance in colonized Enterococcus species in community are starting to attract attention.