Luc Dubreuil

Clinical and microbiological profiles of community-acquired and nosocomial intra-abdominal infections: results of the French prospective, observational EBIIA study

OBJECTIVESnThe EBIIA (Etude épidémiologique Bactério-clinique des Infections Intra-Abdominales) study was designed to describe the clinical, microbiological and resistance profiles of community-acquired and nosocomial intra-abdominal infections (IAIs).nnnPATIENTS AND METHODSnFrom January to July 2005, patients undergoing surgery/interventional drainage for IAIs with a positive microbiological culture were included by 25 French centres. The primary endpoint was the epidemiology of the microorganisms and their resistance to antibiotics. Multivariate analysis was carried out using stepwise logistic regression to assess the factors predictive of death during hospitalization.nnnRESULTSnThree hundred and thirty-one patients (234 community-acquired and 97 nosocomial) were included. The distribution of the microorganisms differed according to the type of infection. Carbapenems and amikacin were the most active agents in vitro against Enterobacteriaceae in both community-acquired and nosocomial infections. Against Pseudomonas aeruginosa, amikacin, imipenem, ceftazidime and ciprofloxacin were the most active agents in community-acquired infections, while imipenem, cefepime and amikacin were the most active in nosocomial cases. Against the Gram-positive bacteria, vancomycin and teicoplanin were the most active in both infections. Against anaerobic bacteria, the most active agents were metronidazole and carbapenems in both groups. Empirical antibiotic therapy adequately targeted the pathogens for 63% of community-acquired and 64% of nosocomial peritonitis. The presence of one or more co-morbidities [odds ratio (OR) = 3.17; P = 0.007], one or more severity criteria (OR = 4.90; P < 0.001) and generalized peritonitis (OR = 3.17; P = 0.006) were predictive of death.nnnCONCLUSIONSnThe principal results of EBIIA are a higher diversity of microorganisms isolated in nosocomial infections and decreased susceptibility among these strains. Despite this, the adequacy of treatment is comparable in the two groups.

nimH, a novel nitroimidazole resistance gene contributing to metronidazole resistance in Bacteroides fragilis

CHRU de Nancy, Laboratoire de Bactériologie, Nancy, France; EA 7300 Stress Immunité Pathogènes, Université de Lorraine, Faculté de Médecine, Vandoeuvre-lès-Nancy, France; Arnaud de Villeneuve Teaching Hospital, Department of Microbiology, Montpellier, France; UMR 5569 HydroSciences Montpellier, Equipe Pathogènes Hydriques Santé Environnements, U.F.R. des Sciences Pharmaceutiques et Biologiques, Université de Montpellier, Montpellier, France; UMR 995-Inserm, LIRIC (Lille Inflammation Research International Center), Université de Lille, Faculté de Pharmacie, Lille, France; Department of Microbiology, Nı̂mes University Hospital, Nı̂mes, France

Antioxidative effect of Bacteroides thetaiotaomicron extracts: superoxide dismutase identification

AbstractBacteroides thetaiotaomicron, a bowel anaerobic commensal, seems to release enzymes detoxifying reactive oxygen species according to our recent work. This opportunistic pathogen would be beneficial in the case of an inflammatory process. To explore its role after an oxidative or nutritive stress, six to seven separate experiments were performed. The bacteria were grown on media restricted in growth factors or supplemented with bile. Their viability was checked after surface protein extraction. The extracts underwent 2D electrophoresis. Gel images were statistically analysed to construct “master” gels. Proteins were identified (peptide-mass fingerprinting technique). The effect of each extract on superoxide anions was evaluated (spectrophotometric method). Superoxide dismutase was identified and a major superoxide anion inhibition was shown by extracts obtained after a nutritive and oxidative stress without significant bacterial death. So, a therapeutic antioxidant potential is firmly hoped for.n FigureThese intestinal commensal Gram negative anaerobic bacilli are able to release a high level of functional superoxide dismutase when grown in minimal medium.

Comparaison de l’activité in vitro de la moxifloxacine, de l’ofloxacine, de la ciprofloxacine, de la clindamycine, du métronidazole et de six β-lactamines vis-à-vis des anaérobies stricts

Resume L’activite in vitro de la moxifloxacine vis-a-vis de 159 anaerobies stricts isoles de prelevements pathologiques humains a ete comparee a celle de l’ofloxacine, de la ciprofloxacine, de la clindamycine, du metronidazole et de 6 β-lactamines (amoxicilline, ticarcilline, seules ou associees a l’acide clavulanique, cefotetan et imipeneme). Les CMI ont ete determinees par une methode de dilution en gelose selon la norme M11A4 du NCCLS. La moxifloxacine a montre une bonne activite sur les 76 souches de Bacteroides fragilis testees, avec une CMI50 de 0,5xa0mg/l. Comparativement les valeurs des CMI50 etaient de 0,125xa0mg/l pour l’imipeneme, et de 0,5xa0mg/l pour le metronidazole. Toutes les souches de Porphyromonas, Prevotella, Fusobacterium et de Peptostreptococcus etaient sensibles a la moxifloxacine a des concentrations ≤xa01xa0mg/l. Sur l’ensemble des 159 souches anaerobies recueillies, aux concentrations de 1, 2 et 4xa0mg/l, la moxifloxacine inhibait respectivement 93,7, 94,9 et 98xa0% des souches. A la difference des autres fluoroquinolones testees, la moxifloxacine presente une bonne activite in vitro vis-a-vis des souches de B. fragilis et de Clostridum. Son activite antibacterienne in vitro vis-a-vis des bacilles a Gram+ et des cocci anaerobies s’est montree superieure a celle de l’ofloxacine et de la ciprofloxacine. Considerant le large spectre de la moxifloxacine vis-a-vis des anaerobies, de futures etudes cliniques permettraient d’evaluer le role de cette molecule dans le traitement d’infections provoquees par ces anaerobies.

Article originalActivité du doripénème sur les bactéries anaérobies strictesActivity of doripenem against anaerobic bacteria

AIMS OF THE STUDYnThis study examines the activity of doripenem, a new carbapenem compound compared with amoxicillin-clavulanic acid, piperacillin+tazobactam, imipenem, clindamycin and metronidazole against 316xa0anaerobes.nnnMETHODSnInoculum preparation and agar dilution method were performed according to the CLSI method for anaerobes (M11A7).nnnRESULTSnAt a concentration of 4μg/ml doripenem and imipenem (IMP) inhibited 122 (96xa0%) and 126 (99xa0%) strains of the Bacteroides fragilis group, respectively. In contrast, doripenem appeared more potent than IMP against Gram-positive anaerobes inhibiting at the same concentration of 4μg/ml 145/145xa0strains (100xa0%) versus 115/145xa0for IMP (79.3xa0%). Against 316xa0anaerobic strains, the carbapenem doripenem had an MIC(50)xa0of 0.25μg/ml and an MIC(90)xa0of 2μg/ml. Results were similar to those for imipenem (MIC(50)xa0of 0.125μg/ml and MIC(90)xa0of 4μg/ml). If we consider the resistant breakpoints of the two carbapenems as defined by EUCAST, the resistance rate for doripenem (MIC>4μg/ml) 1.6xa0% is similar to that of imipenem (MIC>8μg/ml) 1.3xa0%.nnnCONCLUSIONnThus independently of the PK/PD parameters the two carbapenems demonstrated very close activity; doripenem was more potent on Gram-positive anaerobes and slightly less potent against Gram-negative anaerobes mainly the B.xa0fragilis group. Further clinical studies are needed to assess its usefulness in patients.

Activité du doripénème sur les bactéries anaérobies strictes

AIMS OF THE STUDYnThis study examines the activity of doripenem, a new carbapenem compound compared with amoxicillin-clavulanic acid, piperacillin+tazobactam, imipenem, clindamycin and metronidazole against 316xa0anaerobes.nnnMETHODSnInoculum preparation and agar dilution method were performed according to the CLSI method for anaerobes (M11A7).nnnRESULTSnAt a concentration of 4μg/ml doripenem and imipenem (IMP) inhibited 122 (96xa0%) and 126 (99xa0%) strains of the Bacteroides fragilis group, respectively. In contrast, doripenem appeared more potent than IMP against Gram-positive anaerobes inhibiting at the same concentration of 4μg/ml 145/145xa0strains (100xa0%) versus 115/145xa0for IMP (79.3xa0%). Against 316xa0anaerobic strains, the carbapenem doripenem had an MIC(50)xa0of 0.25μg/ml and an MIC(90)xa0of 2μg/ml. Results were similar to those for imipenem (MIC(50)xa0of 0.125μg/ml and MIC(90)xa0of 4μg/ml). If we consider the resistant breakpoints of the two carbapenems as defined by EUCAST, the resistance rate for doripenem (MIC>4μg/ml) 1.6xa0% is similar to that of imipenem (MIC>8μg/ml) 1.3xa0%.nnnCONCLUSIONnThus independently of the PK/PD parameters the two carbapenems demonstrated very close activity; doripenem was more potent on Gram-positive anaerobes and slightly less potent against Gram-negative anaerobes mainly the B.xa0fragilis group. Further clinical studies are needed to assess its usefulness in patients.