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Biomedical subjects

M Chomarat

Publications and source records attributed to M Chomarat.

At least 19 recordsLinked to original sources
PubMed2005

[Nasopharyngeal carriage of Streptococcus pneumoniae in healthy children, 2 to 24 months of age, in New-Caledonia].

OBJECTIVES: The aims of this study were to determine the prevalence of pneumococcal nasopharyngeal carriage in New-Caledonian children less than two years of age, to define risk factors for carriage, and to document the serotypes present in New Caledonia prior to the implementation of the conjugate pneumococcal vaccine. METHOD AND RESULTS: From August 2002 to April 2003, nasopharyngeal samples were collected on 1040 children less than two years of age during scheduled visits to dispensaries for routine immunization. Of the 1040 samples, 544 (52%) were positive for Streptococcus pneumoniae. The percentage of pneumococcal strains with reduced susceptibility to penicillin (PRSP) was 21%. Several risk factors for pneumococcal carriage were identified. These included the Province that the child lived in, the ethnic group, age, and having a sibling less than 6 years of age. Risk factors for carriage of PRSP carriage were similar but also included additional risk factors such as attendance at day care and a history of antibiotic treatment. The eight most frequent serotypes were 6B, 19F, 14, 23F, 6A, 19A, 11A, and 16F. These serotypes accounted for 60% of all strains detected. The most frequent serotypes of PRSP were 14, 9 V, 19F, 23F, and 6B. They were more often identified in european children and 80% were vaccine serotypes. However, overall 250/544 (46%) of all pneumococcal isolates were those included in the 7 serotype vaccine.

Anti-Bacterial Agents↗
PubMed2003

Antibiotic resistance among anaerobic Gram-negative bacilli: lessons from a French multicentric survey.

Temporal changes of antibiotic susceptibilities among anaerobes in France are followed in our laboratory since 1992. For Bacteroides strains, resistance increased from 1992 to 1998 for amoxicillin-clavulanic acid, cefotetan and clindamycin. The present study evaluates the situation in 2000 for 434 Gram-negative anaerobic clinical isolates (obtained from 9 large university hospitals) by testing amoxicillin and ticarcillin alone or combined with clavulanic acid, cefoxitin, cefotetan, imipenem, clindamycin and metronidazole (using the NCCLS-approved method for MIC determination. The main genera tested included Bacteroides (359 strains of the fragilis group), Prevotella (40 strains), Fusobacterium (23 strains) and miscellaneous species (8 strains). Resistance rates within the B. fragilis group were: amoxicillin-clavulanic acid 5.6%, ticarcillin 33%, ticarcillin-clavulanic acid 2%, cefoxitin 13%, cefotetan 44%, clindamycin 33%, imipenem 1% and metronidazole <1%, respectively. Only one strain of B. fragilis was resistant to metronidazole (MIC=64 mg/L); due to the presence of the nimA gene on the chromosome. Resistance to imipenem or metronidazole was only found among the B. fragilis species. These two former drugs excepted, B. fragilis was less resistant to antibiotics than the other species. beta-lactamase production was detected for 357/359 strains of the fragilis group, 26/40 stains of Prevotella and 3/23 strains of Fusobacterium. Dynamic changes of antibacterial resistance are occurring within the B. fragilis group: decreased resistance to amoxicillin-clavulanic acid, ticarcillin-clavulanic acid, imipenem while resistance for cefoxitin, cefotetan, clindamycin continues to increase. Regular antibiotic surveys are needed as a source of information to guide the empirical therapy of anaerobic infections.

Journal Article↗
PubMed2002

[Rhône-Alpes observatory of Streptococcus pneumoniae in 1999: 35 cases of meningitis].

In 1999, in Rhône-Alpes region, in a survey of resistance to antibiotics of Streptococcus pneumoniae, 35 cases of meningitis were observed. A retrospectic questionnary was sent to each participant. MICs to Penicillin, Amoxicillin and Cefotaxime were determined with ATB-PNEUMO gallery or E-test and by disk diffusion for the other antibiotics. The results were interpreted according to the recommendations of the CA-SFM. Mean age was 38.1 years (range : 1 month -78 years) and sex-ratio 2/5. Eight patients had previously received antibiotics, 22 patients had risk factors and 23 were transferred in intensive care unit. The patients received C3G + glycopeptide in 15 of 16 children and in 13/19 adults according to the consensus recommendations. Diagnostic was made on the direct examination of CSF in 83%, and blood cultures was positive in 74.3% of cases. The percentage of PRP was 48.6% with 17.1% of intermediate-amoxicilline and 14.3% intermediate-cefotaxime strains. Resistance to trimethoprim-sulfamethoxazole was 45.7%, to chloramphenicol 30% and to fosfomycin 6.9%. All the strains were susceptible to rifampicin and vancomycin. Among the 17 PRP strains, 7 were belonging to serotype 6 (6 in children). The clinical outcome was fatal in 7 male cases (20%), without risk factors in 3 children and 6 of 7 strains were susceptible to penicillin. Six patients (17%) had auditive and/or neurologic sequellaes. This study shows that nearly 50% of strains isolated in meningitis, in Rhône-Alpes region, were not susceptible to penicillin, and confirms the frequency of sequellaes while the mortality is not related with the resistance of strains to the antibiotics.

Adolescent↗
PubMed2002

Comparative in vitro activity of penicillin G, levofloxacin, moxifloxacin, telithromycin, pristinamycin, quinupristin-dalfopristin and linezolid against ofloxacin-intermediate and -resistant Streptococcus pneumoniae.

Screening by ofloxacin disk was carried out on 1158 strains of Streptococcus pneumoniae in order to investigate the in vitro bacteriostatic activity of penicillin G, levofloxacin, moxifloxacin, telithromycin, linezolid, pristinamycin and quinupristin-dalfopristin against ofloxacin-intermediate and -resistant S. pneumoniae strains. It was concluded that these new antimicrobial agents could be useful for the treatment of pneumococcal infections caused by penicillin-sensitive and -resistant S. pneumoniae, and would represent a valid therapeutic option for patients allergic to beta-lactams, should they prove to be potent in vivo.

Acetamides↗
PubMed2001

[Evaluation of the E-test and the ATB-PNEUMo battery for determining the beta-lactam MIC for Streptococcus pneumoniae in daily practice].

In 1999, during the survey of resistance of Streptococcus pneumoniae to antibiotics by 31 clinical laboratories of Rhône-Alpes area, MIC to penicillin (P), amoxicillin (AMX) and cefotaxime (CTX) of 877 PRP strains or with a diameter of inhibition to oxacillin inferior to 26 mm, were determined by each institution by E-test (n = 220 strains) or ATB-PNEUMO (n = 657 strains). MICs of these three antibiotics were determined by dilution in agar medium by the coordinating center. The essential agreement was respectively for ATB-PNEUMO and E-test 89% versus 84% for P (p > 0.05), of 86% vs 79% for AMX (p < 0.01), and of 91% vs 86% for CTX (p = 0.03). When the strains were classified in clinical category, the differences were significant (p < 0.001) for AMX (85% vs 71%) and for CTX (82% vs 75%) but not for P (73% vs 78%). ATB-PNEUMO method was more sensitive than E-test for the detection of strains susceptible to P (90 vs 73%), to AMX (83 vs 78%) and to CTX (80 vs 72%) and for the strains intermediate to AMX (90 vs 78%). On the contrary, E-test is more specific than ATB-PNEUMO for the detection of P-resistant strains (94 vs 86%). Finally, the specificity of both methods is the same for detection of P-S, AMX-R and CTX-I strains.

Amoxicillin↗
PubMed2001

[Pneumococcal antibiotic resistance in 1999. Results from 19 registries for 1999].

BETA-LACTAM RESISTANCE: Among the 9956 strains of Streptococcus pneumoniae isolated in adults, 39% had some degree of penicillin resistance (reduced susceptibility), but there were relatively few strains highly resistant to penicillin: 10%. Among the 4422 strains isolated in children, the overall rate of penicillin resistance was higher (51%) with 15% highly resistant strains. For amoxicillin, the rate of reduced susceptibility was 25% while 1.4% were amoxicillin-resistant. For ceftaxime the respective figures were 21% and 0.3% OTHER ANTIBIOTIC FAMILIES: Important reduction in the susceptibility of all strains, more pronounced for peni-R strains, for macrolides, cotrimoxazole, tetracyxine and chloramphenicol. Very rare resistance to rifampicin and intact susceptibility to vancomycin. CHILDREN VERSUS ADULTS: The rate of reduced susceptibility to beta-lactams was higher in children: 31% versus 23% for amoxicillin and 21% versus 14% for cefotaxime. However there were only a few rare strains that were amoxicillin and cefotaxime resistant. Unlike what was observed in adults, there were major differences by site of sampling; strains isolated from purulent middle ear fluid exhibited the strongest resistance.

Adult↗
PubMed2000

Resistance of bacteria in urinary tract infections.

Bacterial infection of the urinary tract is a common health problem in young women but also the most common nosocomial infection (>33%) contributing to the mortality of patients, and increasing the duration and cost of hospitalization. Escherichia coli is the most predominant organism and its prevalence varies in different studies. The high consumption of inappropriately prescribed antibiotics, combined with multiple pathology and frequent use of invasive devices, is a major factor contributing to high levels of resistance. There is a serious decrease in susceptibility of E. coli strains to amoxycillin, due to the presence of R-TEM enzymes, to cotrimoxazole and trimethoprim. Nitrofurantoin and fosfomycin-trometamol remain highly active against urinary Enterobacteriaceae, with over 90% of E. coli being susceptible. Knowledge of the most likely causative organisms and the prevalence of resistance pathogens to antimicrobial agents is essential to select antibiotics and to establish guidelines for the empirical treatment of urinary tract infections.

Drug Resistance, Microbial↗
PubMed1999

Infections following peripheral blood progenitor cell transplantation for lymphoproliferative malignancies: etiology and potential risk factors.

PURPOSE: We sought to describe the infections that occur after large-dose chemotherapy, which was followed by autologous peripheral blood progenitor cell transplantation, and to determine their risk factors. PATIENTS AND METHODS: We retrospectively analyzed the occurrence and the characteristics of infections in 277 consecutive patients who received intensive chemotherapy for non-Hodgkin's lymphoma (n = 207), Hodgkin's disease (n = 27), or multiple myeloma (n = 43) in a single institution. Conditioning regimens included total body irradiation in 47% of the cases. Infections occurring within the 30 days after transplant were defined as early infections, whereas infections after that time in patients who had achieved a neutrophil count greater than 1.0 x 10(9)/L (1,000 per microL) were considered as late infections. RESULTS: Within the first 30 days, 172 patients had unexplained fever (62%); infections were documented in 83 patients (30%), most commonly bacteremia (57 patients). Late infections occurred in 64 (26%) of 244 evaluable patients and consisted mainly of varicella zoster virus infections (n = 36) and pneumonia (n = 16). Administration of total body irradiation [odds ratio (OR) = 2.50; 95% confidence interval (CI) 1.4 to 4.5; P = 0.002) and previous use of fludarabine (OR 2.5; CI 1.2 to 5.2; P = 0.02) and a diagnosis of myeloma (OR 2.6; CI 1.2 to 5.6; P = 0.04) were significantly associated with late infections. CONCLUSIONS: This study confirms that infectious toxicity after peripheral blood progenitor cell transplantation is usually moderate, although bacteremia remains a serious problem. Late infections are encountered in about 25% of patients and are more common in those with myeloma, or those who received total body irradiation or fludarabine.

Adolescent↗
PubMed1999

[Can one use probabilistic protocols for antibiotic therapy in intensive care units?].

Due to a large spectrum, empiric antibiotics treatments participate to the increase in bacterial resistance. In order to improve its indications, the implementation of therapeutic guidelines in an ICU was studied. Empiric therapy was administered in 30% of the 178 patients receiving antimicrobial agents. Large spectrum drugs were prescribed in 26% of empiric treatments. The mean duration of empiric antibiotics administration was 3.2 days. It was concluded that it was possible to use guidelines of empiric antibiotic in an intensive care unit.

Anti-Bacterial Agents↗
PubMed1999

[Pneumococcus observatory data in the Rhône-Alps region. Results from 1996].

Throughout 1996, 22 hospital-based laboratories in the Rhône-Alpes region of France collected pneumococcal strains and used a standardized protocol to record the following data; patient age and sex; type of specimen; and determination of susceptibility to at least the following antibiotics: oxacillin 1 microgram and 5 micrograms, erythromycin (Ery), tetracycline (Tet), chloramphenicol (Chl), rifampin (Rmp), and loracarbef. For penicillin-nonsusceptible strains (PNSSs), which were identified based on results with oxacillin, MICs for penicillin G, amoxicillin (Amx), and cefotaxime (Ctx) were determined using the E Test, at the study site and agar dilution at the coordinating center. Of the 1153 strains, 65.5% were from adults and 31.8% from children; patient age was unknown in 2.7% of cases. PNSPs (MIC > 0.06 mg/l) contributed 32.9% of strains (I: 23.3%; R: 9.6%) and were more common in children (41.1%) than in adults (28.1%). The frequency of PNSSs varied across specimen types: 27.9% in blood cultures (305 strains), 15.6% in cerebrospinal fluid (32), 38.7% in protected bronchopulmonary specimens (31), 31.5% in unprotected bronchopulmonary specimens (434), 50.8% in acute otitis media (118), and 34.4% in other specimens (221). Among PNSSs, nonsusceptibility (I + R) to other antibiotics was variable: Ery, 62.1%; Tet, 41.5%; Chl, 40.4%; Rmp, 1.1%. Corresponding figures for the overall strain population were Ery, 33.3%; Tet, 22.7%; Chl, 22.8%; Rmp, 0.9%. In addition, 56.5% of PNSSs exhibited multiple drug resistance. Resistance to amoxicillin (MIC > 2 mg/l) was demonstrated for only 5 strains. No strains were resistant to loracarbef or cefotaxime. Serotypes of the 379 PNSSs were as follows: 23F, 26.6%; 14 (25.6%); 9V (18.2%), 6 (8.7%), 15 (5%), 19 (4.5%).

Adult↗
PubMed1998

[Comparison of the results of the Etest and the method for determining minimum inhibitory concentrations in solid media for penicillin G, amoxicillin, and cefotaxime for S. pneumoniae. A multicenter study].

In 1996-1997 a multicentre study was carried out on 450 Streptococcus pneumoniae strains to compare the MICs and susceptibility categories obtained with the Etest (AB Biodisk) used under routine conditions in 22 hospital laboratories in the Rhône-Alpes region, France, with those obtained by the reference technique of agar dilution performed in a single coordinating centre. Each laboratory detected penicillin resistant pneumococci (PRP) by the oxacillin disk method (1 microgram and 5 micrograms) and determined the MICs of penicillin G (PG), amoxycillin (AMX) and cefotaxime (CTX) by the Etest. All the PRP strains were collected in the coordinating centre where MICs were carried out. The strains were classified as susceptible (S), intermediate (I) and resistant (R) according to the CASFM criteria (Comité de l'Antibiogramme de la Société Française de Microbiologie). The concordance results based on susceptibility categories are as follows: PG = 67.6%, AMX = 63.6%, CTX = 71.5%. Minor errors are as follows: PG = 31.2%, AMX = 36%, CTX = 28.5%. Major and very major errors are rare (0% to 0.6%). Agreement within 1 log2 dilution was obtained for about 80% of the strains. The minor errors results from strains clustering near the breakpoints 1 mg/l (PG) and 0.5 mg/l (AMX, CTX), and from practical difficulties in routine use of the Etest. These discrepancies may result in severe therapeutic problems. This study confirms the limits of the Etest. The authors insist on standardization and rigorous use of the Etest under routine conditions.

Amoxicillin↗
PubMed1997

Reappraisal of the effect of temperature on the growth kinetics of Aeromonas salmonicida.

The effect of temperature (1-34 degrees C) on the maximum specific growth rate of Aeromonas salmonicida could not be described by the classical growth models; for some strains, two optimal temperatures at 23 degrees C and 30 degrees C were observed, as well as an unexpected increase in the pseudolag time above 27 degrees C. This could be explained by the presence of two subsets, notably S-layer+ and S-layer- sub-populations. The A- cells had higher growth parameters (Topt and mu opt) than the A+ cells and were selected by subcultures above 30 degrees C. Yet the relative proportion of A+ cells did not explain all the variation of mu max versus temperature, and the growth kinetics of an Aer. salmonicida isolate remained unpredictable.

Aeromonas↗
PubMed1994

Epidemiology of Staphylococcus aureus in patients with cystic fibrosis.

Seven hundred and thirty-four isolates of Staphylococcus aureus, recovered from the sputum of 238 cystic fibrosis patients in six French hospitals, were characterized by esterase electrophoretic typing, capsular polysaccharide serotyping and phage typing and tested against 14 antibiotics for sensitivity. Thirty-four esterase electrophoretic types were found with a genotypic diversity coefficient of 0.91. Five hundred and forty-eight (78.7%) isolates produced capsular polysaccharide and 350 (50.3%) were type 8. Four hundred and sixty isolates (66.6%) were phage typable and 202 (28.2%) were lysed by group III bacteriophages. No esterase electrophoretic type, capsular type or phage type was specific to cystic fibrosis. Isolates belonged to a wide range of types, similar to strains acquired outside hospitals. Eighty-five patients had three or more consecutive isolates over at least 6 months. The ability of S. aureus to persist for long periods of time has been demonstrated in 73% of them. Methicillin-resistance was encountered among 73 strains (9.8%) which were also multiresistant. Two hundred and eighty-nine (39.9%) strains were sensitive to all antibiotics tested except to penicillin. Pristinamycin and co-trimoxazole were the most effective antibiotics. These results could contribute to the elaboration of a rational approach to the prophylaxis and therapy of respiratory staphylococcal infections in cystic fibrosis patients.

Bacterial Capsules↗