PubMed Health⌕ Search

Biomedical subjects

N Lambert-Zechovsky

Publications and source records attributed to N Lambert-Zechovsky.

At least 37 records · Page 2Linked to original sources
PubMed1995

Activity of beta-lactamase inhibitor combinations on Escherichia coli isolates exhibiting various patterns of resistance to beta-lactam agents.

The efficacy of the clinically available beta-lactam/beta-lactamase inhibitor combinations (amoxicillin/clavulanic acid (CA), ticarcillin/CA, amoxicillin/sulbactam, and piperacillin/tazobactam) was evaluated on 300 amoxicillin-resistant Escherichia coli isolates having the main patterns of beta-lactam resistance. The patterns, which reflect the production of various beta-lactamase enzymes, were analyzed by a principal component analysis of susceptibility to 11 beta-lactam antibiotics or beta-lactam/beta-lactamase inhibitor combinations. Sixty-two percent of strains were not very susceptible to penicillins, cephalothin, or any beta-lactam/beta-lactamase inhibitor combinations except for piperacillin/tazobactam; these strains may represent high-level broad-spectrum beta-lactamase (so-called penicillinase) production phenotype or inhibitor-resistant TEM-like enzyme production phenotype. Of the strains, 14.7% were resistant to amoxicillin and ticarcillin compatible with low-level broad-spectrum beta-lactamase production phenotype; 5.7% were cefoxitin resistant and were postulated to present a high-level cephalosporinase production phenotype; and 2.6% were resistant to cephalothin only, attributable to a low-level cephalosporinase production phenotype. Three percent of strains were intermediate or resistant to cefotaxime and may produce an extended-spectrum beta-lactamase, and the remaining strains (12 %), resistant to all tested antibiotics except for cefotaxime and piperacillin/tazobactam, were hypothesized to produce both broad-spectrum beta-lactamase plus cephalosporinase. The minimal inhibitory concentration (MIC) for these phenotype patterns indicated that combinations of CA plus amoxicillin or ticarcillin, or sulbactam plus amoxicillin, restored the activity of penicillins against phenotype 1 strains, whereas these combinations remained inactive against the other phenotype strains. Piperacillin plus tazobactam showed the best in vitro effect against the strains of all resistance phenotypes.

Amoxicillin↗
PubMed1995

Microbiology of nosocomial sinusitis in intensive care unit patients.

We performed a 2-year microbiological study of specimens of sinus fluid recovered from patients with suspected nosocomial sinusitis in six intensive care units. Over that period, 103 cases of sinusitis were documented by positive culture. The number of cases varied widely from one unit to another and was particularly high in the neurosurgical unit. Cultures were often polymicrobial. The main pathogens were Staphylococcus aureus, Pseudomonas aeruginosa, Acinetobacter baumannii and Enterobacteriaceae. Streptococcus pneumoniae and Haemophilus influenzae were far less frequently isolated. Anaerobes and yeasts were often associated with aerobic bacteria. The pathogen involved was also recovered from bronchopulmonary samples in 50 patients and from blood cultures in seven patients.

Bacteria, Anaerobic↗
PubMed1995

Identification and typing of pyogenic streptococci by enzyme electrophoretic polymorphism.

Polyacrylamide-agarose gel electrophoresis was used to study polymorphism of lactate dehydrogenase (LDH), nucleoside phosphorylase (NSP), phosphoglucose isomerase (PGI), hydroxybutyrate dehydrogenase (HBD), adenylate kinase (ADK) and esterases of 44 strains of Streptococcus pyogenes, 25 group G streptococcal strains, 11 "S. equisimilis" strains, seven S. dysgalactiae strains, four S. canis strains, three S. equi strains and seven S. zooepidemicus strains. Analysis of LDH, NSP, PGI, HBD and ADK provided valuable interspecies differentiation, by showing that four groups of strains corresponded to the four known DNA homology groups. Esterases showed greater intraspecies variation than the other enzymes. The combined analysis of the six enzymes indicated 31 zymotypes among S. pyogenes, 14 in group G streptococci and 11 in "S. equisimilis" strains. This was shown to be an effective technique for typing pyogenic streptococci.

Adenylate Kinase↗
PubMed1995

Brain abscess due to Bacillus macerans following a penetrating periorbital injury.

We report a case of a brain abscess due to Bacillus macerans and Clostridium sp. following a penetrating periorbital injury by a wooden branch. Intracranial penetration by and retention of a foreign body were not suspected initially, and neurological symptoms developed only 2.5 months later. Previously reported cases of brain abscesses due to Bacillus species are reviewed.

Bacillaceae Infections↗
PubMed1994

[Oropharyngeal flora. Epidemiologic survey of prevalence].

OBJECTIVES: Epidemiological surveys which are not frequently carried out in medical practice should provide useful information for the choice of antibiotics to be prescribed in community-acquired infections particularly with the recent development of therapeutic difficulties due to resistant strains. We therefore analyzed the prevalent pharyngeal flora in a general patient population. METHODS: The study was conducted during a single 24-hour period in 1991 by 43 general practitioners and included 645 subjects consulting for benign affections. No patient selection was made. Two pharyngeal swabs were obtained from each subject and cultured in aerobic and anaerobic conditions. Internationally accepted methods for identifying bacteria in pharyngeal samples all performed by one well-equipped laboratory. Beta-lactamase activity was determined with the nitrocephine technique, both directly and after culture. RESULTS: Patient age varied from 16 to 45 years; most (68.5%) consulted for reasons other than ear-nose-throat affections. Only 41 patients (4.3%) consulted for sore throat and 65.4% had not received antibiotics for at least 6 months. Haemophilus influenzae was found in 59.6% of the patients, 20% of the strains were beta-lactamase producers as were 83.7% of the Moraxella catarrhalis strains identified. CONCLUSION: These factors are indicators of potential risk of therapeutic failure when using beta-lactams unstable to beta-lactamases for the treatment of pharyngeal infections.

Adolescent↗
PubMed1994

Comparative efficacy and safety of cefprozil and amoxycillin/clavulanate in the treatment of acute otitis media in children.

Cefprozil is a new oral cephalosporin with activity against the most common pathogens isolated in acute otitis media. This randomized study enrolled 361 patients (mean age 29 months). Physical examination and culture via tympanocentesis were required less than 48 h before therapy. One hundred and ninety-one patients were evaluable for clinical efficacy; 99 received cefprozil (20 mg/kg/day bd) and 92 received amoxycillin/clavulanate (13.3 mg/kg/day tid). Duration of treatment was 7-9 days for 81 patients, 10 days for 105 patients and 11-16 days for five patients. The treatment groups were comparable with respect to demographics, severity of infection and number of previous episodes. Clinical evaluations of efficacy were based on physical examination including otoscopy within a 14 day period after therapy. Satisfactory clinical responses were achieved in 84% of cefprozil-treated patients and 87% of amoxycillin/clavulanate-treated patients. Pathogens most commonly isolated included Haemophilus influenzae (33%) and Streptococcus pneumoniae (22%). All 361 patients were evaluable for safety. Adverse clinical events were reported in 13% (24) of cefprozil-treated patients and 20% (36) of amoxycillin/clavulanate-treated patients. Cefprozil, administered twice a day, is comparable to a regimen of amoxycillin/clavulanate three times a day in the treatment of acute otitis media in children.

Acute Disease↗
PubMed1994

[Epidemiological studies of the susceptibility of Pseudomonas aeruginosa to antibiotics].

The susceptibility to antibiotics of 1367 non-replicate strains of Pseudomonas aeruginosa isolated at Beaujon Hospital between 1990 and 1992 was investigated and compared with the serogroup O and the strain origin (ward, sample). Five betalactam resistance patterns were distinguished according to susceptibility to ticarcillin, piperacillin, ceftazidime and aztreonam,: 1 = SSSS, 2 = RRSS, 3 = RRRR, 4 = RSSR, 5 = RRSR. The other antibiotics studied were imipenem, tobramycin, amikacin, ciprofloxacin and fosfomycin. Resistance to all antibiotics, fosfomycin excepted, was higher in intensive care units than in other wards. The respective frequencies of the phenotypes were: 70.3%, 4.3%, 11.8%, 10.2% and 3.4%. The frequency of pattern 3 steadily increased between 1990 and 1992 at the expense of pattern 1, whereas patterns 2, 4 and 5 remained stable. The most common serogroups were O6 (15.8%), O11 (14.5%) and O1 (9.9%). The O11 strains were more widespread in intensive care units than in other wards and were more resistant to antibiotics. Most of the O12 strains displayed pattern 2 and were highly resistant to antibiotics.

Anti-Bacterial Agents↗
PubMed1993

Killing kinetics of cefuroxime against Streptococcus pneumoniae in an in vitro model simulating serum concentration profiles after intramuscular administration.

The killing kinetics of cefuroxime against 25 Streptococcus pneumoniae isolates with penicillin MICs of < 0.1, 0.1-1.0 and 2 mg/l were studied in an in vitro model simulating the serum concentration profile in healthy adults following a single intramuscular injection of 500 mg. Cefuroxime was bactericidal against the isolates with exquisite or slightly diminished susceptibility to penicillin (-4 and -3.9 log10 cfu/ml killing, respectively) during the 6 h incubation period. In contrast, there was only a 2.8 log10 cfu/ml reduction in the initial inoculum of six of the eight isolates resistant to penicillin (MIC 2 mg/l). The two remaining penicillin-resistant isolates (cefuroxime MIC 8 mg/l) only showed a 2 log10 cfu reduction in the initial inoculum.

Adult↗
PubMed1993

Molecular analysis of multiply recurrent meningitis due to Escherichia coli K1 in an infant.

Bacterial DNA polymorphism was used to document the occurrence of three separate episodes of meningitis caused by Escherichia coli K1 in an infant. The methods employed included determination of the restriction fragment length polymorphism of total DNA and of ribosomal DNA regions as well as DNA fingerprinting by the arbitrarily primed polymerase chain reaction. By these three genotypic approaches, the three isolates obtained from the infant's cerebrospinal fluid on days 9, 34, and 70, respectively, were found to share the same patterns, which were different from the patterns of control strains. Thus, these three episodes of E. coli K1 meningitis were due to a single strain. DNA-based typing techniques seem extremely promising as tools to be used in unraveling the complex mechanisms of recurrent meningitis.

DNA, Bacterial↗
PubMed1993

Identification of a clone of Escherichia coli O103:H2 as a potential agent of hemolytic-uremic syndrome in France.

In a French multicenter study, six verocytotoxin-producing Escherichia coli strains were isolated from the stools of 6 of 69 children suffering from hemolytic-uremic syndrome. All strains belonged to serotype O103:H2, a serotype commonly associated with diarrhea in weaned rabbits in France. To determine whether the strains from humans and rabbits were genetically related, they were compared by analyzing their esterase electropherotypes and the restriction fragment length polymorphisms of the ribosomal DNA regions. A common clonal origin of these pathogenic strains was suggested by their identical esterase electropherotypes and their identical ribotypes, in addition to their identical serotypes. However, strains from humans, which are cytotoxic for HeLa cells through the production of verocytotoxin type 1, do not show adhesion in vitro to HeLa 229 cells and cannot infect rabbits. On the other hand, strains from rabbits do not carry the verocytotoxin type 1 gene, are not cytotoxic for Hela cells, and adhere to ileal villi and HeLa 229 cells because of the expression of their 32-kDa adhesin. Our results therefore identify a clone of verocytotoxin-producing E. coli O103:H2 as a potential agent of hemolytic uremic syndrome in France. They further suggest that clones from humans and rabbits probably have a common origin but that adaptation to the two species occurred by different mechanisms. Thus, they eliminate the hypothesis that the species is horizontally transmitted between rabbits and humans.

Bacterial Toxins↗
PubMed1993

Arbitrarily primed polymerase chain reaction provides rapid differentiation of Proteus mirabilis isolates from a pediatric hospital.

During a systematic survey, maternal carriage of Proteus mirabilis was found over a 25-day period in 18 pregnant women admitted to the delivery ward of our hospital maternity. Five neonates born to these mothers were found to be colonized with P. mirabilis. We report here on the use of DNA fingerprinting by the arbitrarily primed polymerase chain reaction technique (AP-PCR) for the epidemiological investigation of this sudden outbreak. This approach was compared with the analysis of restriction fragment length polymorphisms of ribosomal DNA regions (ribotyping). Results of the AP-PCR and of ribotyping were in complete agreement in showing the genetic unrelatedness of the isolates obtained from each mother. Moreover, the results showed mother-to-infant vertical transmission of P. mirabilis in the neonates. AP-PCR is a rapid and discriminative method which seems particularly well suited to the epidemiological study of P. mirabilis.

Bacterial Typing Techniques↗
PubMed1993

[Clinical, diagnostic and therapeutic aspects of Moraxella catarrhalis infections].

Moraxella catarrhalis is a Gram-negative diplococcus of the Neisseriaceae family now recognized as a cause of acute otitis media in pediatric patients and of lower respiratory tract infections in debilitated adults. The finding that 80% to 90% of strains produce beta-lactamases together with reports of cases of bacteremia and arthritis due to M. catarrhalis suggest an increasing pathogenic role for this organism. Antibiotic susceptibility testing suggests that the greatest bactericidal effect is provided by amoxicillin-clavulanic acid.

Aged↗
PubMed1992

Molecular epidemiological analysis of Pseudomonas aeruginosa strains causing failure of antibiotic therapy in cystic fibrosis patients.

A combination of esterase electrophoretic typing and analysis of the restriction fragment length polymorphism of ribosomal DNA regions (ribotyping) was used to compare 27 Pseudomonas aeruginosa strains isolated before and after two-week courses of anti-pseudomonal treatment in seven cystic fibrosis patients. A total of 12 courses of therapy were studied in which ciprofloxacin, ceftazidime, azlocillin or imipenem were used alone or in combination with tobramycin. Isolates at a count of greater than or equal to 10(6) cfu/ml of sputum were collected when there was evidence of therapeutic failure on the basis of persistence of isolates whether or not they were resistant to the antibiotic used for therapy. Emergence of resistance was observed in ten cases and failure to eradicate sensitive strains in five cases. Among the 27 isolates, eight zymotypes and five ribotypes were identified. With this typing approach, resistant post-therapy isolates were found to be identical to pre-therapy isolates in all cases but one. However, in one case an additional resistant strain was isolated after therapy besides that initially present. In all five cases in which susceptibility was still observed after treatment, pre-therapy and post-therapy isolates were indistinguishable. Using this molecular typing approach, all the strains were typable. Thus combination of esterase typing and ribotyping should improve the analysis of therapeutic failure in cystic fibrosis patients.

Azlocillin↗
PubMed1992

Killing kinetics of five orally administered antibiotics at clinically achievable concentrations against Moraxella catarrhalis.

Time-kill kinetic studies were used to measure the bactericidal activity of amoxicillin/clavulanic acid (in a new form for pediatric use), cefaclor, cefuroxime, cefixime and erythromycin against 30 beta-lactamase producing Moraxella catarrhalis strains. Antibiotics were tested at the mean maximum serum concentration observed after administration of a standard dose and at 0.5 x Cmax, 0.33 x Cmax and 0.25 x Cmax. A 2 log10 reduction in colony counts was obtained with the Cmax of amoxicillin/clavulanic acid and cefixime after 5 h of incubation. After 24 h of incubation a decrease of 3 and 4 log was observed with cefixime and amoxicillin/clavulanic acid respectively. At 0.5 x Cmax and 0.33 x Cmax, bactericidal activity was obtained only with amoxicillin/clavulanic acid.

Amoxicillin↗