PURPOSE: Studies have found different rates of antimicrobial resistance among patients in medical and surgical ICUs. We endeavor to ascertain whether these differences may be a function of geographical separation of the ICUs or differences in the patient populations, by comparing resistance rates among bacteria isolated from medical and surgical patients in a combined Medical/Surgical ICU.
METHODS: We retrospectively evaluated the results of bacterial cultures of each patient admitted to the ICU between February, 2005 and September, 2006. Data collection included patient demographics and culture and sensitivity results. Differences in the frequency of antimicrobial resistance among bacteria from medical and surgical patients were analyzed using the Fisher's exact test.
RESULTS: Two hundred sixty-four patients with four hundred thirty positive cultures were studied; 170 medical and 94 surgical patients. The mean ages were 69 and 71 years old, respectively. Organisms were grouped into four classes: Staphylococcus aureus (n=126), non-lactose fermenting gram negative bacilli (NLFGN) (n=105), Enterococcus sp. (n=49), and gram negative enteric bacteria (n=137). In the S. aureus group, there were no significant differences between medical and surgical patients in resistance to oxacillin (55% vs. 65%, p=0.32). Among the Enterococcus group, differences in the prevalence of resistance to vancomycin (56% vs. 54%, p=1.0) and ampicillin (52% vs. 62%, p=0.57) were also found to be non-significant. Differences in NLFGN resistance to ciprofloxacin (45% vs. 44%, p=1.0), ceftazidime (22% vs. 32%, p=0.27), and gentamicin (35% vs. 32%, p=0.83) were found to be non-significant. No significant difference was found to exist among enteric gram negative bacilli bacteria in regards to resistance to ciprofloxacin (17% vs. 24%, p=0.30), and gentamicin (12% vs. 5%, p=0.22).
CONCLUSION: Reported differences in resistance patterns among bacteria cultured from medical and surgical patients may be due to geographical separation of the ICUs as opposed to differences in the patient characteristics.
CLINICAL IMPLICATIONS: These results suggest that intensive care unit specific antibiograms remain a useful tool to guide the choice of antimicrobial therapy, even in Medical/Surgical ICUs.
DISCLOSURE: Jason Akulian, No Financial Disclosure Information; No Product/Research Disclosure Information