Évolution de la sensibilité et épidémiologie de la résistance des entérobactéries de ville au cours des enquêtes Vigil'Roc

[Retrospective study of bacteremia diagnosed in an emergency department: frequency, susceptibility of microorganisms, and impact on therapeutic management]

OBJECTIVE

The authors had for aim to determine the prevalence of bacteremia diagnosed in an emergency department (ED), the susceptibility of microorganisms to antibiotics, and the impact on therapeutic management.

DESIGN

A retrospective analysis was made on patient features, microbiological ecology, susceptibility to antibiotics, and modalities of antimicrobial therapy in the Georges Pompidou European hospital ED of Hôpital, between 1 November 2001 and 30 June 2002.

RESULTS

One thousand four hundred and thirty two blood cultures were obtained from 1069 patients. The rate of positive cultures was 12%, but only 8.7% (n = 125) were proved as true bacteremia. The most frequently identified organisms were: Enterobacteriaceae (n = 63, 39.4%) with a predominance of Escherichia coli (n = 48, 30%), and Streptococcus pneumoniae (n = 16, 10%). Forty two cases of pyelonephritis and 34 of prostatitis both due to E. coli were diagnosed. 76.5% of these were resistant to amoxicillin, 64.7% to amoxicillin-clavulanic acid, 11.8% to ciprofloxacin, and 44% to cotrimoxazole. No resistance to third generation cephalosporin was detected in E. coli isolates. Fourteen S. pneumoniae pneumonia cases were diagnosed. 57.1% of isolates presented with a decreased susceptibility to penicillin (CMI > 0.1 mg/l). Susceptibility to amoxicillin and cefotaxim was 85.7% and 92.9% respectively. Blood culture was the only exam available for bacterial diagnosis in 51.5% of true bacteremia. 1.6% of blood cultures from ED samples had an impact on therapeutic management.

CONCLUSIONS

Blood culture is a relevant exam for the diagnosis of infection in patients admitted to the ED.

Escherichia coli : résistance aux quinolones et aux β-lactamines des souches cliniques isolées en Franche-Comté

AIM OF THE STUDY

Numerous European studies have reported an increase of resistance to quinolones among E. coli. We conducted a regional study to update our knowledge on this evolution.

MATERIALS AND METHODS

We evaluated the resistance phenotype and genotype of 115 clinical strains of E. coli. We collected data on individual treatment with fluoroquinolones, and the evolution of the use of these antimicrobial agents.

RESULTS

Resistance to nalidixic acid and ciprofloxacin was 13.0 and 6.9, respectively. The frequency of resistance increased from 1999 to 2001, from 7.5% to 13.0% for nalidixic acid and from 5.4% to 6.9% for fluoroquinolones. Resistance to quinolones was significantly associated to beta-lactams resistance and was slightly higher for nosocomial isolates compared to community-acquired isolates. Previous treatment with fluoroquinolones was the major risk factor associated to E. coli resistance. From 1997 to 2001, fluoroquinolones use has increased in our hospital and particularly in the community. Analysis of molecular epidemiology shows a large clonal diversity among E. coli isolates.

CONCLUSION

This study confirms the evolution through resistance to quinolones of E. coli isolates. This observation is not due to dissemination of resistant clonal strains and the selective pressure exerted by fluoroquinolones influences this evolution. Therapeutic alternatives, surveillance, and restriction of fluoroquinolones use are needed to control this spread of resistance.

Increasing prevalence of antimicrobial resistance among Enterobacteriaceae uropathogens in Dakar, Senegal: a multicenter study

To assess antibiotic susceptibility among Enterobacteriaceae isolated in urine from outpatients in Dakar, Senegal, a prospective multicenter study involving 3 laboratories had been conducted between June and October 2001. During this period, 300 strains were isolated and susceptibility testing was performed against antibiotics commonly used in treatment of community-acquired urinary tract infections (UTI). E. coli and K. pneumoniae represented 89% of isolates. The overall resistance rates of ampicillin, amoxicillin-clavulanic acid, nalidixic acid, fluoroquinolones and cotrimoxazole were respectively 77.3%, 34.7%, 14.7%, 13.3%, and 55%. In the light of these results, a re-evaluation of first line therapies and prudent use of fluoroquinolones is advised. At the same time a continued surveillance of antimicrobial resistance should be developed in Senegal in order to control the emergence of multidrug resistant strains and to establish a national therapeutic guideline for treatment of UTI.