Gram-negative Bacillary Resistance in a Surgical Intensive Care Unit: A Four-Year Surveillance

Abstract

Topical administration of non-absorbable anti-infective drugs (e.g. tobramycin, polymyxin E (colistin) and amphotericin B) in combination with short-term systemic cefotaxime can prevent nosocomial infections in surgical intensive care patients. However, multiresistant gram-negative bacilli can emerge during this administration. We compared the pattern of resistance among gram-negative bacilli before (1983 and 1984) and after (1985 and 1986) the introduction of this regimen. Since 1984, tobramycin has been the aminoglycoside of choice for both therapy and prophylaxis. We observed a significant decrease in gentamicin resistance in Pseudomonas and Acinetobacter strains in 1985 and 1986 compared to 1984. Bacterial resistance to tobramycin for the isolated gram-negative bacilli did not change in the four-year period and was less than 20%. The percentage of resistance to cefotaxime was very low for enterobacteria (c. 5%) and was about 20% for Pseudomonas and Acinetobacter strains. An increase in resistance to other β-lactam agents in gram-negative bacilli was not observed in 1985 and 1986.