[Therapeutic impact of streptococcal and enterococcal bacteremia in hematology patients]

Reduced susceptibility to amoxicillin of oral streptococci following amoxicillin exposure

As antibiotic pressure often triggers bacterial resistance, the use of short-duration therapies is increasingly recommended. The objective of the present study was to evaluate both the clinical efficiency and the impact on oral streptococci of a 3 day versus a 7 day amoxicillin therapy for odontogenic infection requiring tooth extraction. On day 0, patients were randomly assigned to a 3 day or 7 day amoxicillin treatment. The tooth was extracted on day 2 and the post-operative follow-up was carried out on day 9. Oral flora was collected on days 0, 9 and 30, and the susceptibility of the streptococci to amoxicillin was determined. The results showed that treatment with amoxicillin for 3 or 7 days had a similar clinical efficiency, and also induced similar selection of oral streptococci with reduced susceptibility to amoxicillin, suggesting that the selection of strains with reduced susceptibility to amoxicillin is a rapid phenomenon, appearing even with short-duration therapies.

Étude sur sept ans des isolats d’hémocultures dans un service d’hématologie clinique

GOAL

This study had for aim to analyze the epidemiology of strains identified in blood cultures (hôpital d'instruction des armées Percy, Clamart, France, hematology unit) to compare the rate of identified micro-organisms with literature data, and to search for a possible correlation between antibiotherapy management and evolution of resistance profiles.

MATERIAL AND METHODS

All the micro-organisms (N = 690) collected over seven years (January 1996 to December 2002), from blood cultures of hospitalized patients in conventional and sterile sector were studied.

RESULTS

Gram positive cocci rate (GPC) was 62.6% and Gram negative bacilli (GNB) 31.3%. Evolution in time showed a decrease of GPC and an increase of GNB, notably the non fermenting Gram negative bacilli, leading to an equal rate by 2001-2002. The most frequently identified species were Staphylococcus epidermidis (36.4%), Escherichia coli (8.7%), Pseudomonas aeruginosa (6.8%), and Staphylococcus aureus (4.9%). The rate of methicillin-resistant staphylococci was 63.6%. Fifty-five percent of E. coli strains had a penicillinase phenotype. Pseudomonas aeruginosa resistance was 8.5, 8.5, 6.4 and 8.5%, respectively for ceftazidime, piperacillin-tazobactam, imipenem, and amikacin.

CONCLUSION

This study showed a tendency to inversion of former bacteremia epidemiology with increasing negative Gram bacilli. It justifies the antibiotherapy protocols adopted in the hematology unit.