The Rising Influx of Multidrug-Resistant Gram-Negative Bacilli into a Tertiary Care Hospital

Division of Infectious Diseases, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA.
Clinical Infectious Diseases (Impact Factor: 8.89). 06/2005; 40(12):1792-8. DOI: 10.1086/430314
Source: PubMed


The prevalence of multidrug resistance (MDR) among gram-negative bacilli is rapidly increasing. Quantification of the prevalence and the common antimicrobial coresistance patterns of MDR gram-negative bacilli (MDR-GNB) isolates recovered from patients at hospital admission, as well as identification of patients with a high risk of harboring MDR-GNB, would have important implications for patient care.
Over a 6-year period, patients who harbored MDR-GNB (i.e., patients who had MDR-GNB isolates recovered from clinical cultures within the first 48 h after hospital admission) were identified. "MDR-GNB isolates" were defined as Pseudomonas aeruginosa, Escherichia coli, Enterobacter cloacae, and Klebsiella species isolates with resistance to at least 3 antimicrobial groups. A case-control study was performed to determine the independent risk factors for harboring MDR-GNB at hospital admission.
Between 1998 and 2003, the prevalence of MDR-GNB isolates recovered from patients at hospital admission increased significantly for all isolate species (P < .001), with the exception of P. aeruginosa (P = .09). Of 464 MDR-GNB isolates, 12%, 35%, and 53% of isolates were coresistant to 5, 4, and 3 antimicrobial groups, respectively. Multivariable analysis identified age > or = 65 years (odds ratio [OR], 2.8; 95% confidence interval [CI], 1.1-7.4; P < .04), prior exposure to antibiotics for > or = 14 days (OR, 8.7; 95% CI, 2.5 -30; P < .001), and prior residence in a long-term care facility (OR, 3.5; 95% CI, 1.3-9.4; P < .01) as independent risk factors for harboring MDR-GNB at hospital admission.
A substantial number of patients harbor MDR-GNB at hospital admission. Identification of common coresistance patterns among MDR-GNB isolates may assist in the selection of empirical antimicrobial therapy for patients with a high risk of harboring MDR-GNB.

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    • "– HAI - localized or systemic condition: 1) that results from adverse reaction to the presence of an infectious agent(s) or its toxin(s) and 2) that was present 48 hours or more after hospital admission and not incubating at hospital admission time [15]. "
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    • "In contrast to previous studies [16,19], older age was not shown to be a predictor for acquiring MDR organisms; on the contrary, older patients were less likely to have a COBSI with MDR GNB. Our data suggest a potential shift in the epidemiology of MDR GNB to a younger patient population, and this was not limited to patients with underlying medical conditions or predisposing healthcare-associated risk factors. "
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