PubMed Health⌕ Search

Biomedical subjects

J C Ghnassia

Publications and source records attributed to J C Ghnassia.

At least 19 recordsLinked to original sources

E-test antibiotics susceptibility of strict anaerobic bacteria.

The E-test is convenient for testing susceptibility of anaerobes. From September 1998 to September 1999, 194 strains (105 Gram-positive bacteria, 89 Gram-negative bacteria) of clinically relevant samples were tested against five antibiotics benzylpenicillin, amoxicillin-clavulanic acid, clindamycin, metronidazole and imipenem on blood agar plates. Resistance to benzyl penicillin is widespread and Gram-negative bacteria and resistance to amoxicillin-clavulanic acid is exceptional. Metronidazole is very effective against anaerobes except non-spore-forming aerotolerant Gram-positive rods and Peptostreptococcus micros.

Journal Article↗

[Routine use of gene amplification for pertussis diagnosis in children].

OBJECTIVES: The resurgence of whooping cough observed in France convinced us to develop a specific PCR assay to detect B. pertussis in nasopharyngeal secretions in parallel of the culture. The aim of our study was to show the value of the PCR in routine diagnosis. MATERIAL AND METHODS: From November 1996 to August 2000, in two hospitals located in the Yvelines (France), the children consulting for a cough compatible with the diagnosis of whooping cough were included in this study. A questionnaire including clinical, biological and radiological items was completed for each one of these patients. A culture of Bordetella and a detection by PCR of B. pertussis were carried out on each nasopharyngeal aspirate. The diagnosis of whooping cough was retained if the detection was positive in PCR and/or culture. RESULTS: Among the 215 investigated children with suspected cases of whooping cough, the diagnosis was positive for 45 (20.9%), of which 39 were less than one year old (median: three months). Sixteen (35.5,%) were positive at the same time for both the PCR and the culture, 26 (57.8%) for only PCR and three (6.7%) for only culture. The PCR was positive in 93.3% of the cases. The results were obtained with an average time of 48 hours. The culture was positive in 61.2% of the cases with an average time of six days. The monthly distribution of the cases of whooping cough was very inhomogeneous and of epidemic appearance. The majority of the cases was located between two periods: 42% between November 1996 and September 1997 and 40% between November 1999 and August 2000. Among the infected children, 15 were less than two months old and were not yet vaccinated; among the 24 others infants, a delay in the vaccine calendar was noted in 50% of the cases. Four children between six and 14 years old were correctly vaccinated. The evolution was favourable in all the children. CONCLUSION: The PCR due to its sensitivity, its specificity and its rapidity offers to the clinician a powerful tool for the diagnosis of whooping cough. Nevertheless, the culture must be associated with the PCR, in order to follow the epidemiology and the sensitivity to antibiotics of B. pertussis.

Adolescent↗

Susceptibility of Enterobacteriaceae to beta-lactam agents and fluoroquinolones: a 3-year survey in France.

OBJECTIVE: To assess trends in the susceptibility to beta-lactam agents and to fluoroquinolones of clinically relevant Enterobacteriaceae isolated over a 3-year period in 14 French hospital laboratories. METHODS: During the second quarter of 1996, 1997 and 1998, 180 consecutive non-duplicate isolates of Enterobacteriaceae were collected in each center. Sixteen beta-lactams and four quinolones were tested by the disk diffusion method. In addition, the double-disk synergy test was used to screen for the production of extended-spectrum beta-lactamase (ESBL). RESULTS: Totals of 2507, 2312 and 2506 clinical isolates were obtained in each period, respectively. The distribution of Enterobacteriaceae species according to clinical specimens and wards was similar in each study period. No significant variation in the susceptibility rates to beta-lactams and fluoroquinolones was observed, except in Klebsiella pneumoniae and Enterobacter aerogenes. The prevalence of ESBL-producing isolates decreased from 18% to 9% in the former, while it increased from 32% to 54% in the latter. At the same time, the susceptibility to ofloxacin and pefloxacin increased for K. pneumoniae (P < 0.003) and cephalosporinase-producing species (P < 0.05), except Enterobacter spp. CONCLUSION: Over the 3-year study period beta-lactams and fluoroquinolones remained highly active against Enterobacteriaceae clinical isolates, with the exception of E. aerogenes, probably as a result of the dissemination of multiresistant clones in French hospitals.

Anti-Bacterial Agents↗

[Evaluation of Hemofast MRSA for identification of Staphylococcus aureus and detection of methicillin-resistance staphylococci, directly in blood culture broths].

The newly developed Hemofast MRSA system for Staphylococcus aureus identification and methicillin-resistant staphylococci (MRS) detection in blood culture broths was evaluated in 106 Bactec broths containing grapelike clusters of Gram-positive cocci. All 26 S. aureus positive broths were correctly identified by Hemofast MRSA within two hours, and 81% were identified within one hour. Sensitivity and specificity were both 100%. Accuracy of MRS detection was 100%, i.e., no discrepancies versus the agar diffusion method were found. When the 28 broths containing coagulase negative staphylococci (CNS) were tested using an inoculum ten fold larger than for S. aureus testing, a number of discrepancy were recorded. For 49 other broths containing CNS, accuracy was 98.5% when the test was interpreted based on the growth rate of the strain, according to the manufacturer's instructions. One broth containing S. epidermidis strain susceptible yielded a false result with Hemofast MRSA, indicating that it probably contained a contaminant. The other discrepancies occurred with specimens containing mixed populations with CNS or a Micrococcus strain. Most (85%) results were available within 4 hrs 30 min, irrespective of the S. aureus or CNS strains. Avoiding the isolation step on agar, Hemofast MRSA saves 24 to 48 hours, thus allowing earlier antistaphylococcal treatment.

Bacteriological Techniques↗

[An Acinetobacter baumanii outbreak at the Versailles Hospital Center].

A. baumannii is a multiresistant bacteria which is recognised as responsible for nosocomial infections and hospital outbreaks. The control of these outbreaks depends on the strain's typing and on the fight's policy against nosocomial infections. An outbreak of A. baumannii is occurred to patients who were hospitalized in Centre Hospitalier de Versailles. To investigate this outbreak, we have determined the biotype (Bouvet's method), the succeptibility pattern (disk diffusion and agar dilution results were analysed with the hierarchical classification and main component analysis) and the total DNA macrorestriction pattern (Pulse Field Gel Electrophoresis using SmaI restriction enzyme). A risk factors for A. baumannii acquisition were delineated in case-control study. During 2 years, 38 patients have been infected or colonized to A. baumannii. Thirty two patients were hospitalized in ICU. We studied 38 non repetitive clinical isolates and 9 strains of the patient's rooms. Four biotypes were defined by the Bouvet's typing method. Fourteen groups were obtained when succeptibility results were analysed with the hierarchical classification and 6 with the main composant analysis. The molecular typing permit us to define 4 epidemic and 6 sporadic strains. All the epidemic strains were isolated on ICU hospitalized patients. Our study has shown wide contamination in patient's rooms (Water tap, dry surfaces, patient's mattresses...). Environmental objects have been a major risk factor for A. baumannii acquisition. The control of this outbreak has been possible by application of hygienic measures (hands washing, isolment, meticulous cleaning of the ICU and environmental controls). No new case is occurred in the last year. Typing methods and case-control study are necessary to investigate cross-infections and take efficient measures against these outbreaks.

Acinetobacter↗

[Staphylococcus aureus resistant to methicillin. Survey of prevalence in Yvelines hospitals].

During 2 months (01.01.95-28.02.95), we noted for each Staphylococcus aureus (SA) isolates, identification and susceptibility methods, hospital size, medical speciality, source, penicillin (P) and methicillin (M) susceptibility. For each non repetitive methicillin resistant SA we noted phenotype of aminoglycoside resistance of SA to 6 antistaphylococci drugs. We isolated 399 SA, SAP sensitives 6.5%, methicillin resistant SA (MRSA) 31.8%. MRSA in acute care unit 28.4%, non acute care unit 61.7%, surgery 28.6%, medicine 36.5%, orthopedics 34.5%, pédiatrics 4%, ICU 38.8%, others 10.3%. MRSA from wound 28.2%, respiratory tract 38.3% blood 22.5%, urine 58.5%, others 25.8% - MRSA kanamycin 1.7%, kanamycin tobramycin 36.2%, kanamycin, tobramycin, gentamicin 56.9% - MRSA erythromycin 79.5%, pefloxacin 91.3%, rifampicin 53.5%, acide fusidique 8.7%, fosfomycine 18.9%, TMP SMZ 5.5%. The proportion MRSA is equivalent among medical specialities predominant in urine cultures and respiratory tract. It should be better to carry on the survey for more than two months in each hospital.

Aminoglycosides↗

[Predictive value of a rapid negativity of serum virus C viremia during treatment with interferon alpha in patients with chronic hepatitis C].

Interferon alpha (INF) used for chronic hepatitis C treatment induces a response in less than 25% of patients. The aim of this study was to appreciate the predictive value of the delay of clearance of hepatitis C virus (HCV) viremia after onset therapy and to compare it with other virological markers such as viral load before treatment and viral type. Thirty one patients with chronic hepatitis C, treated with 3 MU Interferon, 3 times a week for 6 months, were followed until 6 months post-treatment. Response was defined according to the normalisation of transaminases levels and loss of HCV viremia. Five patients were long term responder, eleven patients were complete to relapse responder and fifteen patients were non responder. Serum HCV RNA level, HCV type and serial detection of serum HCV RNA were determined and correlated with the long term response to INF. Patients with long term response had lower pre-INF viral load compared to the complete to relapse responder or to the non responder (p < 0.001). A rapid clearance of serum HCV RNA (1 month) is observed for all the long term responder (p < 0.001). The lowest viral load is also observed in these patients (p < 0 05). By contrast, although the number of patient is low, we were not able to observe a relation between the viral type and the response to treatment. In conclusion this data indicate that the delay of clearance of HCV RNA is also a good predictor of response to INF therapy. Furthermore a rapid clearance of HCV RNA in patients with a very weak pre-INF viral load is strongly associated with long term response (positive predictive value: 100%).

Antiviral Agents↗

[Choice and monitoring of the treatment of systemic mycoses. Value and limitations of in vitro tests].

Systemic fungal infections are an important cause of morbidity and mortality among immunocompromised patients. New antifungal agents, such as triazoles, are now available, and the place of in vitro tests has to be discussed. It has been shown that interlaboratory reproducibility of in vitro susceptibility tests against fungi was low, due to the lack of standardization. Recently, the NCCLS defined conditions permitting a good interlaboratory reproducibility. However, the predictive value of in vitro susceptibility tests on the therapeutic outcome remain to be demonstrated, and is now under investigation. At the present time, susceptibility testing can be useful: in patients treated by amphotericin B for a severe fungal infection and who do not improve under therapy; to detect resistance to 5-fluorocytosine; to compare the sensitivity to triazoles before and after treatment, in case of therapeutic failure. Serum levels monitoring is useful to prevent the toxicity due to 5-fluorocytosine and to control the digestive absorption of triazoles, especially the lipophilic compound itraconazole.

Acquired Immunodeficiency Syndrome↗

[Multicenter study of the sensitivity to beta-lactam antibiotics of 1,707 strains of Pseudomonas aeruginosa isolated at a general hospital].

1,707 non replicate clinical strains of Pseudomonas aeruginosa from non teaching hospitals were investigated. Beta-lactam antibiotics were tested by agar disk diffusion method. Variance analysis revealed a significant interaction between strains and experimental laboratories. The bacterial population was grouped according to the diameters of inhibition zones of antibiogram, into five phenotypes. Pseudomonas aeruginosa is frequently isolated from urines and pulmonary sampling, rarely from blood cultures. Resistance to beta-lactams increased significantly with the duration of hospitalisation, and age of patients. Clinical strains are significantly more resistant in blood cultures, and for strains isolated from reanimation. 84% of strains are susceptible to ticarcillin.

Adolescent↗

[Bacteriology of the bile ducts and antibiotic prophylaxis].

The gallbladder wall, gallbladder lumen and bile duct intraoperative sampling materials had been examined in 52 patients with an operation on the biliary tract. All patients were treated by only one infusion before operation: 1 g ceftriaxone was given to 26 patients and 2 g ceftriaxone to the 26 others. Bacterial species were isolated on twenty patients. There was no significant difference in infection rate and organism identity between bacterial flora isolated from patients receiving 1 g ceftriaxone and patients receiving 2 g. Isolated germs were enterobacteriaceae (15) streptococci (14) and anaerobic bacteria (8). The mean count of bacteria in bile is 10(4) germs/ml. Half positive sampling materials contains more than one bacterial strain. The bacterial flora isolated from bile has characteristics of mixed flora infection. Ceftriaxone had a good efficacy in antibiotic prophylaxis.

Adult↗

[Characteristics of penicillinase-producing strains of Neisseria gonorrhoeae isolated in France, 1979-1986].

Penicillinase producing Neisseria gonorrhoeae PPNG, had been first isolated in France in 1979. Since, they regularly increased if we considered France on the whole. From 1979 to 1986, 284 strains had been collected by a multicentric group. The frequency of isolation was strongly different in France, unknown in some region they rose 12% in specific areas in Paris. The PPNG strains were more frequently isolated from male than female (sex ratio was higher with PPNG than for non producing strain). They were more often responsible of complicated infections in female than male at the same rate than the non producing strains. Auxotype distribution was different between producing and non producing strains. Plasmidic content from african type (Af) was almost the same than from asian type (As). Strains with Af type associated with the conjugative plasmid were increasing.

Adult↗

[In vitro bactericidal activity of polyvinylpyrrolidone iodine on Neisseria gonorrhoeae].

A standardized methodology was used to study the in vitro behavior of different strains of Neisseria gonorrhoeae when treated with povidone-iodine. The bactericidal activity of the antiseptic was appraised using the dilution-neutralization technique on four gonococcal strains, two of which produced a beta-lactamase. Bactericidal activity in aqueous medium was observed down to a dilution of 1/128. This result specifies the conditions under which this antiseptic is active against Neisseria gonorrhoeae.

Microbial Sensitivity Tests↗

[Superoxide dismutase and catalase activity in HeLa 229 cells infected with Chlamydia trachomatis].

Cytosolic superoxide dismutase (SOD) activity was found to increase with time during HeLa cell culture, this increase being due exclusively to Mn-SOD. Infection of the cells by Chlamydia trachomatis resulted in a further enhancement of this Mn-SOD activity, whereas cytosolic catalase activity was decreased in these infected cells. Superoxide (O-2.) being able to induce Mn-SOD and to inhibit catalase, these data suggest that Chlamydia trachomatis infection could be responsible for an increase in O-2. production by the infected HeLa cells.

Catalase↗

[Serum antibacterial activity during antibiotic treatment in automated bacteriology].

The conventional serum-dilution bactericidal test used for monitoring antibiotic therapy in severely infected in patients requires 72 h. Use of an automaton would be expected to provide faster results. We tested the MS-2 diagnostic automaton which performs kinetic analysis of bacterial growth. A relation between exponential growth onset time and initial bacterial concentration of the inoculum was first determined using successive ratio 10 dilutions. Sixty-two serum samples from twenty-one patients with endocarditis or septicemia were examined. A selection of findings is presented. Results of the automatic method and serum-dilution bactericidal test are studied comparatively. From our data we define the major advantages of automation: only 0.65 ml of serum and 10 minutes are needed to perform the test and results are obtained in five to twelve hours according to the bacterial strain. This new technique could be integrated in the monitoring protocol of severe infections.

Ampicillin↗