Screening for multidrug-resistant bacteria as a predictive test for subsequent onset of nosocomial infection.

OBJECTIVE: To investigate whether carriage of multidrug-resistant bacteria is a risk factor for nosocomial infection and whether detection of carriage is predictive of subsequent onset of nosocomial infection. METHODS: In this observational cohort (study period, June 1998 through October 2002), nasal and rectal swab specimens from 412 consecutive patients admitted to the intensive care unit were tested for carriage of multidrug-resistant bacteria. Concomitantly, the bacteria responsible for any subsequent nosocomial infection, the date of infection, and some of the known clinical risk factors for nosocomial infection were noted. These factors were adjusted for potential confounders, using a Cox model stratified on the propensity score of multidrug-resistant bacteria carriage. The diagnostic characteristics of a carriage test, including the positive and negative diagnostic likelihood ratios, were calculated for all strata of the propensity score. RESULTS: Forty-two patients were carrying multidrug-resistant bacteria. Nosocomial infection occurred in 95 patients, of whom 16 (38%) were carriers, and 79 (83%) were noncarriers (P=.01). After adjustment for potential confounders, statistical analysis revealed that carriage remained a risk factor for nosocomial infection (relative risk, 2.08 [95% confidence interval {CI}, 1.13-3.81]). Receipt of antibiotic treatment at the time of intensive care unit admission was found to be protective against nosocomial infection. A positive result of test for detection of carriage seemed to be an efficient predictor of subsequent nosocomial infection (positive diagnostic likelihood ratio, 2.05 [95% CI, 1.15-3.66]), although a negative test result was not a predictor of subsequent nosocomial infection (negative likelihood ratio, 0.91 [95% CI, 0.73-1.11]). CONCLUSION: Carriage proved to be a risk factor for subsequent nosocomial infection. However, the carriage test was useful as a predictive tool only for patients with a positive test result.

[Acute severe leukoencephalitis with posterior lesions due to Borrelia burgdorferi infection]. / Leuco-encéphalite aiguë à tropisme postérieur révélant précocement une maladie de Lyme.

INTRODUCTION: Central nervous system manifestations represent 0.54 to 8% of neurological complication in Lyme disease. OBSERVATION: A 78-year-old woman presented a severe meningo-encephalitis with visual disorders (agnosia, alexia) progressing towards coma. Cranial magnetic resonance imaging revealed large areas of hypersignal T2 in the white matter of the lower, parieto-occipital lobes and left temporal lobe. The cerebrospinal fluid (CSF) contained 16 then 293 white corpuscles/mm3 of lympho-monocytes, increased protein level from 2.67 to 5.83 g/l and an increase in IgG index with oligoclonal distribution of IgG. Serological Elisa analysis for Lyme disease was slightly positive in blood (confirmed by western blot) but clearly in the CSF (IgG and IgM). Treatment with ceftriaxone followed by methylprednisolone provided clinical improvement 3 months later. DISCUSSION: Acute meningo-encephalitis is often benign, protein-like and of good prognosis: the gnosic visual disorders with posterior leukoencephalopathy are unusual. A blood level of specific antibodies slightly positive on Elisa at the early stage of the infection warrants confirmation by Western blot in the blood and by Elisa in the CSF. Additional corticosteroid therapy may be required in the severe forms that evoke acute disseminated encephalomyelitis.

[Evaluation of 7 endoscope washer-disinfectors: bactericidal activity of the disinfectants, antibacterial efficacity of paired washer-disinfector products]. / Evaluation de sept laveurs-désinfecteurs d'endoscopes: activité bactéricide des désinfectants, efficacité antibactérienne des couples laveur-désinfecteur/produits.

The authors studied seven automatic washer disinfectors for flexible endoscopes with two methods. The first method, a microdilution method, studied the bactericidal activity of the seven disinfectants against 21 strains: four reference strains, 14 hospital strains reported in the literature as nosocomial strains responsible for infections transmitted by flexible endoscopes and three vancomycin-resistant Enterococci. The ability of the seven automatic washer disinfectors to decontaminate flexible endoscopes following inoculation with four reference strains was studied with the second method. There were three kinds of results: the results of three automatic washer disinfectors in conformity with both methods; the results of three automatic washer disinfectors conformity with 1 method only; the results of one automatic washer disinfector without conformity with any methods. Both methods should be used for evaluation of automatic washer disinfector. Then, these results emphasize the necessity to modify the use of disinfectants and/or the systems of some automatic washer disinfectors.

[Is the quantitative antibiogram a reliable epidemiological marker for Pseudomonas aeruginosa infections? Comparison with pulsed field electrophoresis]. / L'antibiogramme quantitatif est-il un marqueur épidémiologique fiable des infections à Pseudomonas aeruginosa? Comparaison à l'électrophorèse en champ pulsé.

Epidemiologic supervision of P. aeruginosa infections is a daily care for microbiologists. The aim of this study is to evaluate quantitative antibiogram, which compare strains by calculation of euclidian distances from inhibition zone diameters on agar, compared with pulse field gel electrophoresis (PFGE) results. 53 isolates of P. aeruginosa obtained from bronchial secretions of 26 patients in intensive care unit are typed by conventional disk diffusion test on agar with 11 usual antibiotics. Dendrogram of euclidian distances is performed by Taxotron computer program (P.A.D. Grimont, Institute Pasteur, Paris); results are compared with 53 PFGE patterns after restriction with Spe I (Genepath system, BIO-RAD). Quantitative antibiogram has a high discriminatory power for beta-lactamin resistant strains: 27 isolates from 11 patients clustered in 5 types where PFGE discerned 5 patterns. The discriminatory power is low for beta-lactamin sensible strains: 26 isolates from 15 patients clustered in 8 types where PFGE discerned 19 patterns, but serotyping method combined with quantitative antibiogram restore a high disriminatory power for beta-lactamin sensible strains.

[Evaluation of a micromethod for the bactericidal activity of five disinfectants on 108 hospital strains]. / Evaluation par une microméthode de l'activité bactéricide de cinq désinfectants sur 108 souches hospitalières.

The authors studied 5 disinfectants containing aldehyde and quaternary ammonium against 108 hospital strains. The minimal bactericidal activities (MBC) were determined with a microdilution method and the dilution-neutralization method (AFNOR T 72-150). The microdilution method results were validated using the MBCs of four reference strains tested with the dilution-neutralization method (AFNOR T 72-150). 3 disinfectants proved to be valuable. 1 disinfectant was valuable but with a MBC toward all bacteria only a dilution away from the dilution of use. 1 disinfectant was determined as unsatisfactory as 9.5 p. cent of all strains proved resistant toward it. All disinfectants matched AFNOR standards; but those specifications did not match toward hospital strains. Such an evaluation using a simple and reliable method should be of use.