Alterations in the Microbial Flora and in the Incidence of Bacteremia at a University Hospital after Adoption of Amikacin as the Sole Formulary Aminoglycoside

• Published in: Clinical infectious diseases 1992-04, Vol.14 (4), p.908-915
• Main Authors: King, John W., White, Margaret C., Todd, John R., Conrad, Steven A.
• Format: Article
• Language: English
• Subjects: Amikacin - pharmacology; Amikacin - therapeutic use; Aminoglycosides; Antibiotics; Bacteremia; Bacteremia - drug therapy; Bacteremia - epidemiology; Bacteremia - microbiology; Blood; Clinical Infectious Disease Articles; Death; Drug Resistance, Microbial; Genera; Gentamicins - pharmacology; Gentamicins - therapeutic use; Gram-Negative Bacteria - drug effects; Gram-Negative Bacteria - isolation & purification; Gram-Negative Bacterial Infections - drug therapy; Gram-Negative Bacterial Infections - epidemiology; Gram-Negative Bacterial Infections - microbiology; Gram-Positive Bacteria - isolation & purification; Gram-Positive Bacterial Infections - drug therapy; Gram-Positive Bacterial Infections - epidemiology; Gram-Positive Bacterial Infections - microbiology; Humans; Incidence; Infections; Louisiana - epidemiology; Mortality; Prospective Studies; Statistical significance; Tobramycin - pharmacology; Tobramycin - therapeutic use; University hospitals
• ISSN: 1058-4838; 1537-6591
• DOI: 10.1093/clinids/14.4.908

Because of the rapid emergence of resistance to gentamicin and tobramycin among isolates of aerobic and facultative gram-negative bacteria at our university hospital, we designed a prospective study to track aminoglycoside resistance, bacteremic episodes, and bacteremia-associated deaths before and after the institution of amikacin as the sole formulary aminoglycoside. From June 1984 through June 1987 (immediately before this policy change), amikacin accounted for only 20% of patient-days of aminoglycoside therapy, and rates of resistance to gentamicin, tobramycin, and amikacin among aerobic and facultative gram-negative bacterial isolates were 12.8%, 10.8%, and 5.9%, respectively. During the next 30 months (immediately after the change in policy), amikacin accounted for 98% of patient-days of aminoglycoside therapy, and rates of resistance to gentamicin, tobramycin, and amikacin were 6.3%, 5.0%, and 3.3%, respectively. Furthermore, during the latter 30 months, the incidence of both bacteremia and bacteremia-associated death decreased significantly. Hospitals at which resistance to gentamicin or tobramycin is increasing among the gram-negative flora may benefit from the use of amikacin as the principal aminoglycoside.