Évolution de la sensibilité de Streptococcus pneumoniae aux antibiotiques: résultats de l'observatoire du pneumocoque Alsace (année 2005)

OBJECTIVES

Between 1st January 2005 and 31st December 2005, 232 strains of Streptococcus pneumoniae were collected in the Alsace county from participating laboratories (one from university hospital, 7 from general hospitals and 12 private laboratories) to assess their susceptibility to penicillin and evaluated serogroups of strains.

METHOD

The coordinating centre performed MICs by the reference agar dilution test, interpreted according to CA-SFM breakpoints. Others antibiotics (erythromycin, cotrimoxazole, tetracycline...) were tested by agar diffusion, ATB-PNEUMO gallery or VITEK gallery (BioMérieux, France) by each participating laboratory. Data were processed, using 4th dimension software.

RESULTS

Strains were collected from 151 blood samples, 38 ear pus, 11 cerebrospinal fluids, 8 pleural liquids and 24 representative pulmonary samples. The prevalence of pneumococci with decreased susceptibility to penicillin G (PDSP) is 35.1% (pulmonary samples excluded). The rate of PNSP decreases for all types of samples compared with other years of surveillance 2003 (44.0%). The rate of blood samples decreases for first time between the creation of Pneumococcal Observatory. The high-level resistance tend to decrease and began low. The PDSP are rather resistant to erythromycin, cotrimoxazole and fosfomycin. Among the PDSP, the most prevalent serotypes were 14, 19, 6 and 9.

CONCLUSION

Among pneumococcal strains, the rate of PDSP tend however to decrease in 2005 compared with 2003. The rate stays inferior to the observed rates in other French counties where the same decreasing is described.

[Bacterial resistance and antimicrobial therapy in respiratory medicine and intensive care]

Nosocomial pneumonia is the leading cause of mortality among the infections produced by multi-resistant microorganisms in intensive care units (ICU). The solution of this problem created by the colonization and infection of the respiratory tract is beyond respiratory medicine and requires a multi-disciplinary approach, involving other nosocomial infections in the ICU. Up to 80% ICU patients receive antibiotics for severe infections or prophylactically, frequently with no clear justification for these treatments. The extended use of antibiotics increases the problem by exerting a selective pressure favoring the development of resistant organisms. Some evidences suggest that the infections produced by multi-resistant pathogens increase the mortality of nosocomial pneumonia. The following mechanisms are responsible for the acquisition of resistance: alteration of bacterial wall permeability; production of inactivating enzymes, modification of the target site, or eflux. Resistance is genetically transmitted by chromosomes or by plasmids. At the present time staphylococci (Staphylococcus aureus and coagulase-negative staphylococci) and enterococci predominate among the gram-positives, and non-fermenters (Pseudomonas aeruginosa, Acinetobacter spp) and some Enterobacteriaceae among the gram-negatives. Antibiotics are the main determinants of the problem of resistance but also partially their vehicle. The solution of this problem includes infection control, diagnosis and adequate therapy (sufficient doses chosen according to the case and based on prefixed antibiotic politics). These antibiotic politics imply a rational use, reconsideration of the initial scheme according to microbiologic results, limited use of combination antimicrobial strategies, restricted list of drugs, rotation and correct use of prophylaxis.

Multicenter study of street foods in 13 towns on four continents by the food and environmental hygiene study group of the international network of pasteur and associated institutes

An international multicenter study of ready-to-eat foods, sandwiches, and ice creams or sorbets sold in the streets and their vendors was carried out to assess the microbiological quality of these foods and to identify characteristics of the vendors possibly associated with pathogens. Thirteen towns in Africa, America, Asia, and Oceania were involved in the study. A single protocol was used in all 13 centers: representative sampling was by random selection of vendors and a sample of foods bought from each of these vendors at a time and date selected at random. Microbiological analyses were carried out using standardized Association Française de Normalisation methods, and the use of a standardized questionnaire to collect data concerning the characteristics of the vendors. Fifteen surveys were carried out, with 3,003 food samples from 1,268 vendors. The proportion of unsatisfactory food samples was between 12.7 and 82.9% for ice creams and sorbets and between 11.3 and 92% for sandwiches. For ice creams and sorbets, the sale of a large number of units (>80 per day) increased the risk of unsatisfactory food by a factor of 2.8 (95% confidence interval [CI]: 1.5 to 5.1), lack of training in food hygiene by 6.6 (95% CI: 1.1 to 50). and by a factor of 2.8 (95% CI: 1.4 to 5.4) for mobile vendors. These risk factors were not identified for sandwiches, this difference may be due to the presence of a cooking step in their preparation. These results show that the poor microbiological quality of these street foods constitutes a potential hazard to public health, that the extent of this hazard varies between the cities studied, and that vendors' health education in food safety is a crucial factor in the prevention of foodborne infections.

Impact of BAL data on the therapy and outcome of ventilator-associated pneumonia

STUDY OBJECTIVE

To define the impact of BAL data on the selection of antibiotics and the outcomes of patients with ventilator-associated pneumonia (VAP).

DESIGN

Prospective observation and bronchoscopy with BAL, performed within 24 h of establishing a clinical diagnosis of a new episode of hospital-acquired VAP or progression of a prior episode of nosocomial pneumonia (NP).

SETTING

A 15-bed medical and surgical ICU.

PATIENTS

One hundred thirty-two patients hospitalized for more than 72 h, who were mechanically ventilated and had a new or progressive lung infiltrate plus at least two of the following three clinical criteria for VAP: abnormal temperature (> 38 degrees C or < 35 degrees C), abnormal leukocyte count (> 10,000/mm3 or < 3,000/mm3), purulent bronchial secretions.

INTERVENTIONS

Bronchoscopy with BAL within 24 h of establishing a clinical diagnosis of VAP or progression of an infiltrate due to prior VAP or NP. All patients received antibiotics, 107 prior to bronchoscopy and 25 immediately after bronchoscopy.

RESULTS

Sixty-five of the 132 patients were BAL positive (BAL[+]), satisfying a microbiologic definition of VAP (> 10(4) cfu/mL), while 67 were BAL negative (BAL[-]). The BAL(+) patients had no differences in mortality, prior antibiotic use, and demographic features when compared with the BAL(-) patients. More of the BAL(+) patients (38/65) satisfied all three clinical criteria of VAP than did BAL(-) patients (24/67) (p < 0.05). A total of 50 BAL(+) patients received antibiotic therapy prior to bronchoscopy, and when this prior therapy was adequate (n = 16), as defined by the results of BAL, then mortality was 38%, while if prior therapy was inadequate (n = 34), mortality was 91% (p < 0.001), and if no therapy was given (n = 15), mortality was 60%. When therapy changes were made after bronchoscopy, more patients (n = 42) received adequate therapy, but mortality in this group was comparable to mortality among those who continued to receive inadequate therapy (n = 23). A total of 46 of the 65 BAL(+) patients died, with 23 of these deaths occurring during the 48 h after the bronchoscopy, before BAL results were known. When BAL data became available, 37 of the 42 surviving patients received adequate therapy, but their mortality was comparable to the patients who continued to receive inadequate therapy.

CONCLUSIONS

Patients with a strong clinical suspicion of VAP have a high mortality rate, regardless of whether BAL cultures confirm the clinical diagnosis of VAP. When adequate antibiotic therapy is initiated very early (ie, before performing bronchoscopy), mortality rate is reduced if this empiric therapy is adequate, compared to when this therapy is inadequate or no therapy is given. If adequate therapy is delayed until bronchoscopy is performed or until BAL results are known, mortality is higher than if it had been given at the time of first establishing a clinical diagnosis of VAP. When patients were changed from inadequate antibiotic therapy to adequate therapy, based on the results of BAL, mortality was comparable to those who continued to receive inadequate therapy. Thus, even if bronchoscopy can accurately define the microbial etiology of VAP, this information becomes available too late to influence survival.

[Tachycardia-bradycardia syndrome. An electrophysiological and pharmacological study (author's transl)]

In nine patients with the tachycardia-bradycardia syndrome, a dysfunction of sinusal automatism was observed, shown by a prolonged recovery time of sinus node for six of the patients, and by an insufficient response to atropine in all nine. In two of the five patients, where a study of seno-atrial conduction was possible a conduction defect at this level was noticed. In three patients (33%), asystole was observed: in one patient in the course of a tachycardial crisis; during the passage of an atrial fibrillation in sinusal rhythm in another, and following premature isolated atrial pulsations in the third. The observations of asystole pause in the third patient following premature isolated beats which were longer than those induced electrically, led to the conclusion that, more than a sinusal automatism or sino-atrial conduction defect, asystole can be due to repetitive re-entries that are not reproduced at the level of the sino-atrial junction. The atrial response obtained in another patient with atrial stimulation slightly superior to the threshold, seems to exclude an atrial inexcitability hypothesis. The paroxysmal tachycardia and the atrial fibrillation were the most frequently noted arrhythmias; atrial flutter was only rarely observed. A rotation of rhythm disturbances was recorded in four of the nine patients, both on diverse occasions and during one crisis. The atrial electrostimulation performed on a patient during asystole pauses occurred spontaneously during the course of a tachy cardial crisis, allowed conduction of the atria only for 1-2 stimuli, and did not impede the recovery of the tachycardial paroxysm. It is probable that the conduction disturbances and/or the atrial excitability, which have the same determining cause of sinusal dysfunction, can be responsible for atrial arrhythmias, with the characteristic symptom of the tachycardia-bradycardia syndrome.