Antibiotic susceptibility in aerobic gram-negative bacilli isolated in intensive care units in 39 French teaching hospitals (ICU study).
OBJECTIVE
Evaluation of the distribution and antibiotic susceptibility of the aerobic gram-negative bacilli (AGNB) isolated from patients in intensive care units (ICU study).


METHODS
Microbiological study carried out in 1991 in 39 teaching hospitals. A standardized method was used to determine the minimum inhibitory concentrations of 12 antibiotics against 3366 strains of AGNB (close to 100 strains per hospital) during a period of 3 months.


RESULTS
The 2773 initial strains (i.e., the first AGNB isolate for a given species and a given patient) were mainly isolated from the respiratory tract (34.4%), urinary tract (23%), or blood (9.6%) and were mainly Pseudomonas aeruginosa (22.9%), Escherichia coli (22%), Acinetobacter (9.7%), and Klebsiella pneumoniae (8.3%). E. coli was prominent in urine and blood and P. aeruginosa in the respiratory tract. Overall, the rate of susceptibility of AGNB was 58 to 65% to piperacillin, cefotaxime, and gentamicin; 69 to 75% to aztreonam, tobramycin, and ciprofloxacin; 83% to ceftazidime; and 91% to imipenem. The overall rates of susceptibility were higher for the initial strains isolated from blood than for those from the urinary or respiratory tracts, mostly reflecting differences in species distribution. Susceptibility rates were lower for the 593 repeat strains (i.e., all the subsequent isolates for a given species and a given patient) than for the initial strains, mostly due to the higher proportion of resistant species (P. aeruginosa 45.9%) but also due to the difference in susceptibility rates for some species-antibiotic combinations. Concomitant resistance (i.e., resistance to several antibiotics due to independent mechanisms of resistance) was marked between beta-lactams and aminoglycosides or quinolones, particularly in P. aeruginosa and K. pneumoniae.


CONCLUSIONS
Rates of resistance in AGNB as a whole and in particular species (P. aeruginosa, Klebsiella), as well as frequency of concomitant resistance found in the French ICU study, were higher than those found in ICU studies conducted with the same methodology in Belgium, The Netherlands, and Germany, which may reflect differences in case mix.
Jarlier
V
V
Laboratoire de Bactériologie, Hôpital Pitié-Salpêtrière, Paris, France.
Fosse
T
T
Philippon
A
A
D001420:Bacteria, Aerobic; D003428:Cross Infection / Q000453:epidemiology / Q000382:microbiology*; D004352:Drug Resistance, Microbial; D005602:France / Q000453:epidemiology; D016905:Gram-Negative Bacterial Infections / Q000453:epidemiology / Q000382:microbiology*; D019538:Health Care Surveys; D006784:Hospitals, Teaching; D006801:Humans; D017053:Infection Control; D007362:Intensive Care Units / Q000706:statistics & numerical data*; D008826:Microbial Sensitivity Tests