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C Bebear

Publications and source records attributed to C Bebear.

At least 19 recordsLinked to original sources
PubMed2002

Evaluation of the BDProbeTec ET DTB assay(1) for direct detection of Mycobacterium tuberculosis complex from clinical samples.

The purpose of this study was to evaluate the ability of BDProbeTec ET DTB system to detect Mycobacterium tuberculosis complex directly from clinical specimens. A total of 628 specimens (553 respiratory and 75 non respiratory specimens) were collected from 478 patients. These samples were tested with the BDProbeTec ET DTB assay and results were compared with acid fast microscopy and culture. Sixty eight out of 77 culture positive M. tuberculosis complex samples were detected with overall sensitivity and specificity of 89.5% and 98.2% respectively. Overall sensitivity was 100% in smear positive samples and 79% in smear negative samples. After resolution of discrepant results, sensitivity and specificity for respiratory samples were 91.6% and 98.7% respectively. BDProbeTec ET DTB assay demonstrated to be a rapid, sensitive and specific method for detection of M. tuberculosis complex.

Bacteriological Techniques↗
PubMed2002

Culture-negative endocarditis due to Chlamydia pneumoniae.

We report on the case of a 54-year-old woman diagnosed as having culture-negative endocarditis (clinical and histopathologic evidence compatible with a recent episode of endocarditis). The responsibility of Chlamydia pneumoniae in this episode of endocarditis was suggested by a serological study and was then confirmed by the positive results of PCR and in situ hybridization tests with aortic and mitral valves tissues. To our knowledge, this is the first case of endocarditis due to C. pneumoniae confirmed by molecular biology-based techniques.

Blood↗
PubMed2001

Direct genotyping and nucleotide sequence analysis of VS1 and VS2 of the Omp1 gene of Chlamydia trachomatis from Moroccan trachomatous specimens.

To determine the range of ocular strains of Chlamydia trachomatis circulating in southern Morocco, where trachoma is endemic, and to compare the value of the molecular methods for genotyping C. trachomatis, ocular specimens were subjected to a direct Omp1 PCR-restriction fragment length polymorphism (RFLP)-based analysis and direct sequencing. PCR-RFLP analysis shows that the Ba genotype represents the most frequent one (63%), followed by genotype A (45%), whereas no B or C genotypes were identified among the 53 out of 108 specimens that were strongly positive in the Omp1 CT1-CT5 PCR. Our results further show that the notion of interfamily and intrafamily transmission is very likely. To confirm the genotype identity of C. trachomatis as determined by PCR-RFLP, 16 selected specimens were sequenced across variable sequence 1 (VS1) and 2 (VS2). No discrepancies were found between PCR-RFLP typing and the genotype identity confirmed by nucleotide sequencing of the PCR product. Our results clearly indicate that both molecular methods of typing chlamydiae (i.e., PCR-RFLP and sequencing) are important and have specific applications for clinical epidemiological purposes. This is the case for individuals infected with more than one clonal population of C. trachomatis. The unambiguous nucleotide sequencing therefore defines an important epidemiologic descriptor for the infected patient whether the source is from a clonal population of organisms or whether it represents a more dynamic process of strain dominance or genetic change. Furthermore, Omp1 genotyping affords the necessary approach to epidemiologic investigations in areas of the world endemic for trachoma, where only one or two serovars are known to predominate.

Bacterial Outer Membrane Proteins↗
PubMed2001

Electronic ventilator temperature sensors as a potential source of respiratory tract colonization with Stenotrophomonas maltophilia.

Stenotrophomonas maltophilia (S. maltophilia) is an important cause of nosocomial infection among ventilated and immunocompromised patients, and among patients receiving broad-spectrum antimicrobials. We report a cluster of patients in a surgical intensive care unit who were colonized or infected with S. maltophilia. An epidemiological investigation was initiated after surveillance data revealed that eight patients were culture-positive from sputum for S. maltophilia in the preceding month. Review of respiratory care procedures revealed that when mechanical ventilators were serviced between patients, the electronic temperature probes used with servo-controlled humidifiers were wiped with inadequate disinfection. We collected cultures of case-patient room surfaces, sinks and ventilator equipment. S. maltophilia was recovered from room surfaces, ventilator expiratory circuits and a temperature sensor which had been kept in ambient air after disinfection. Patients and environmental isolates were examined by RAPD-PCR. Three clinical isolates and one environmental isolate had the same profile, which suggests cross-contamination or common source exposure. The outbreak was controlled by adequate disinfection of the temperature sensors. No single epidemic strain was identified but several observations support the conclusion that the temperature probes contributed to the outbreak.

Cross Infection↗
PubMed2001

Disseminated Mycobacterium lentiflavum infection in a human immunodeficiency virus-infected patient.

We report the first case of Mycobacterium lentiflavum disseminated infection in a human immunodeficiency virus-infected patient. Conventional identification procedures failed to identify the mycobacterial strain, but sequencing of the 16S rRNA gene led to the species identification. Furthermore, we describe here the analysis of the 16S-23S rRNA internal transcribed spacer sequence of M. lentiflavum.

AIDS-Related Opportunistic Infections↗
PubMed2000

Molecular typing of Mycoplasma pneumoniae strains by PCR-based methods and pulsed-field gel electrophoresis. Application to French and Danish isolates.

Restriction fragment length polymorphism (RFLP) analysis of the amplified P1 gene was used to type 153 strains of Mycoplasma pneumoniae isolated in France between 1977 and 1994, and in Denmark between 1962 and 1994, and an additional group of 28 strains isolated from Belgium and Germany between 1990 and 1993. Random amplified polymorphic DNA (RAPD) analysis was tested on French, Belgian and German strains. Both methods separated the strains into two groups corresponding to the two reference strains M129 (group I) and FH (group II), and gave concordant results. When 75 selected strains of different geographical origin were analysed by pulsed-field gel electrophoresis (PFGE), strains of group II fell into two closely related subgroups, subgroup IIa corresponding to the reference strain FH, and subgroup IIb. Most of the strains isolated in Denmark in the period 1962-86 belonged to group I. Almost all strains isolated in France and Denmark between 1987 and 1988 were from group II, the two subgroups being present. In 1991-3, almost all strains from France as well as Denmark, Germany and Belgium belonged to group I.

Bacterial Typing Techniques↗
PubMed2000

Utility of fiberoptic bronchoscopy in neutropenic patients admitted to the intensive care unit with pulmonary infiltrates.

OBJECTIVE: To analyze the impact of fiberoptic bronchoscopy and bronchoalveolar lavage (BAL) on guiding the treatment and intensive care unit (ICU) clinical outcome in neutropenic patients with pulmonary infiltrates admitted to the ICU. DESIGN: Prospective collection of data. SETTING: Medical ICU in a teaching hospital. PATIENTS: During a 6-yr period, we analyzed the results of 93 fiberoptic bronchoscopies plus BALs performed in 93 consecutive neutropenic ICU patients. We separated the patients into two groups according to the cause of neutropenia (high-dose chemotherapy [n = 41] or stem cell transplantation [SCT; n = 52]). RESULTS: Of the 93 BALs, 53 were performed to evaluate diffuse infiltrates and 42 were performed on mechanically ventilated patients. Forty-nine percent of BALs (46 patients) were diagnostic, with a significantly better yield in ICU patients with high-dose chemotherapy-induced neutropenia (26 of 41 BALs). The number of cases of proven infectious pneumonia was significantly higher in this group of ICU neutropenic patients. In patients who underwent SCT, diffuse infiltrates were statistically correlated with a negative result of BAL. Twenty-six patients who underwent diagnostic BALs changed therapy. Sixteen complications (17%) occurred with only two intubations. The overall mortality rate in the ICU and the mortality rate in mechanically ventilated neutropenic patients were 71% and 93%, respectively. In neutropenic patients who underwent SCT, the mortality rate was statistically higher in patients in whom no diagnosis was established. Patients who had a diagnostic BAL that changed therapy did not have an increased probability of survival compared with patients who had a BAL that did not change therapy. CONCLUSIONS: The use of routine diagnostic BAL in ICU neutropenic patients with pulmonary infiltrates is difficult to establish, even if BAL is helpful in the management of these critically ill patients. BAL in our ICU neutropenic patient population had an acceptable overall diagnostic yield (49%), which was higher in ICU patients with chemotherapy-induced neutropenia. Nevertheless, in the ICU, if BAL had a low complication rate, it had infrequently led to changed treatment and was not associated with improved patient survival.

Adult↗
PubMed2000

Comparative activities of telithromycin (HMR 3647), levofloxacin, and other antimicrobial agents against human mycoplasmas.

The activities of telithromycin and levofloxacin against 99 mycoplasma strains were compared to those of several macrolides, ofloxacin, and doxycycline. Telithromycin MICs of </=0.25 microgram/ml were found for all isolates, except for Mycoplasma hominis, while levofloxacin was active at concentrations of </=1 microgram/ml against all species studied.

Anti-Bacterial Agents↗
PubMed2000

In vitro activity of trovafloxacin compared to those of five antimicrobials against mycoplasmas including Mycoplasma hominis and Ureaplasma urealyticum fluoroquinolone-resistant isolates that have been genetically characterized.

The in vitro activity of trovafloxacin against 125 strains of Mycoplasma species and Ureaplasma urealyticum, including fluoroquinolone-susceptible and fluoroquinolone-resistant species, was compared to those of other fluoroquinolones, doxycycline, and erythromycin. The MIC at which 90% of isolates are inhibited for all fluoroquinolone-susceptible strains was 0.25 microg/ml. Whatever the associated mutations, trovafloxacin exhibited greater activity than the other fluoroquinolones tested against fluoroquinolone-resistant Mycoplasma hominis and U. urealyticum isolates.

Anti-Bacterial Agents↗
PubMed2000

Rotation and restricted use of antibiotics in a medical intensive care unit. Impact on the incidence of ventilator-associated pneumonia caused by antibiotic-resistant gram-negative bacteria.

To test the hypothesis that a new program of antibiotic strategy control can minimize the incidence of ventilator-associated pneumonia (VAP) caused by potentially antibiotic-resistant microorganisms, we performed a prospective before-after study in 3, 455 patients admitted to a single intensive care unit over a 4-yr period. Regarding the bacterial ecology and the increasing antimicrobial resistance in our medical intensive care unit (MICU), we decided to vary our choice of empiric and therapeutic antibiotic treatment, with a supervised rotation, and a restricted use of ceftazidime and ciprofloxacin, which were widely prescribed before this scheduled change. For all patients, VAP was diagnosed based on the results of quantitative culture of bronchoalveolar lavage specimens (>/= 10(4) cfu/ml). We studied 1,044 and 1,022 patients requiring more than 48 h of mechanical ventilation (MV), respectively, in the before-period (2 yr: 1995-1996) and the after-period (2 yr: 1997-1998). We observed a decrease from 231 consecutive episodes of VAP in the before-period to 161 episodes of VAP in the after-period (p < 0.01), particularly for VAP occurring before 7 d of MV. The total number of potentially antibiotic-resistant gram-negative bacilli responsible for VAP such as Pseudomonas aeruginosa, Burkholderia cepacia, Steno-trophomonas maltophilia, and Acinetobacter baumanii decreased from 140 to 79 isolated bacilli. The susceptibilities of these bacteria to the antibiotics regimen increased significantly, especially for P. aeruginosa and B. cepacia. The percentage of methicillin-sensitive Staphylococcus aureus increased significantly from 40% to 60% of S. aureus responsible for VAP. These results suggest that a new strategy of antibiotics use could be an efficient means to reduce the incidence of VAP caused by antibiotic-resistant bacteria. Nevertheless, further studies are needed to validate these data.

Aged↗
PubMed1999

Severe respiratory failure requiring ICU admission in bone marrow transplant recipients.

Two groups of bone marrow transplant (BMT) recipients with febrile noncardiogenic respiratory failure requiring intensive care unit (ICU) admission, in the early phase of bone marrow transplantation were compared: those who had proven infectious pneumonia and those in whom bronchoalveolar lavage (BAL) failed to establish a diagnosis. Thirty-eight consecutive neutropenic BMT recipients admitted to an ICU with febrile noncardiogenic respiratory failure were enrolled. All of them underwent a BAL with viral, fungal, bacterial, and histopathological examinations. Lung biopsies were performed in nonsurviving patients in order to compare with BAL results. Haematological, biological, respiratory failure and other organ failure parameters, infectious results, outcome, and lung biopsy results were evaluated. BAL allowed an infectious diagnosis to be established in 16 BMT recipients. No aetiology was proven in 22 patients. Without a significant difference in respiratory failure parameters on ICU admission, noninvasive continuous positive airway pressure ventilation, which was given to 11 patients in each group, was significantly more successful in patients with proven infectious pneumonia (6 of 11 versus 0 of 11 patients) and enabled endotracheal intubation to be avoided in significantly more patients with infectious disease (10 of 16 versus 22 of 22 patients). The evolution of patients without diagnosis was significantly different with more frequent renal failure, hepatic failure, and death (20 of 22 versus 9 of 16 patients). Post mortem biopsies confirmed the absence of micro-organisms, but endothelial damage and fibrosis was found in 14 of the 22 patients. In conclusion, in the early phase of bone marrow transplantation the recipients without proven aetiology of pneumonia have a worse outcome than grafted patients with proven infectious pneumonia.

Adult↗
PubMed1999

Agrobacterium radiobacter as a cause of pseudobacteremia.

Agrobacterium radiobacter was isolated from 15 blood cultures collected from 15 newborns. Contamination of blood cultures was suspected because, in most cases, the babies' illnesses seemed incompatible with infection. A radiobacter was isolated from citrated tubes used for clotting-factor studies. Review of venipuncture technique revealed that occasionally the coagulation study tubes were being inoculated before the blood-culture bottles. This investigation demonstrated how an environmental source coupled with faulty technique caused a cluster of false-positive blood cultures.

Bacteremia↗
PubMed1999

Mutations in the gyrA, parC, and parE genes associated with fluoroquinolone resistance in clinical isolates of Mycoplasma hominis.

Five clinical isolates of Mycoplasma hominis from three different patients were examined for resistance to fluoroquinolones; some of these isolates were probably identical. All five isolates harbored amino acid substitutions in the quinolone resistance-determining regions of both DNA gyrase (GyrA) and topoisomerase IV (ParC or ParE). Furthermore, the novobiocin MIC for three isolates showed a significant increase. This is the first characterization of fluoroquinolone-resistant clinical mycoplasma isolates from humans.

Anti-Infective Agents↗
PubMed1999

Molecular characterization of TEM-59 (IRT-17), a novel inhibitor-resistant TEM-derived beta-lactamase in a clinical isolate of Klebsiella oxytoca.

A clinical isolate of Klebsiella oxytoca (Kox 443) was found to have a low-level resistance to broad-spectrum penicillins (MICs of amoxicillin and ticarcillin, 256 and 32 microg/ml, respectively), without substantial potentiation by 2 microg of clavulanic acid per ml (amoxicillin- and ticarcillin-clavulanate, 128 and 8 microg/ml, respectively), while being fully susceptible to cephalosporins and other beta-lactam antibiotics. These resistances were carried by a ca. 50-kb conjugative plasmid that encodes a single beta-lactamase with a pI of 5.6. Compared to TEM-2, this enzyme exhibited a 3- to 30-fold higher Km and a decreased maximal hydrolysis rate for beta-lactams; higher concentrations of suicide inactivators (5- to 500-fold higher concentrations giving a 50% reduction in hydrolysis) were required for inhibition. Nucleotide sequence analysis revealed identity between the blaTEM gene of Kox 443 and the blaTEM-2 gene, except for a single A-to-G change at position 590, leading to the amino acid change from Ser-130 Gly. This mutation has not been reported previously in the TEM type beta-lactamases produced by clinical strains, and the novel enzyme was called TEM-59 (alternative name IRT-17). This is the first description of an inhibitor-resistant TEM-derived enzyme in the species K. oxytoca.

Aged↗
PubMed1997

Characterization of Mycoplasma hominis mutations involved in resistance to fluoroquinolones.

Fluoroquinolone-resistant mutants of Mycoplasma hominis were selected in vitro from the PG21 susceptible reference strain either by multistep selection on increasing concentrations of various fluoroquinolones or by one-step selection on agar medium with ofloxacin. The quinolone resistance-determining regions (QRDR) of the structural genes encoding the A and b subunits of DNA gyrase were amplified by PCR, and the nucleotide sequences of eight multistep-selected resistant strains were compared to those of susceptible strain PG21. Four high-level resistant mutants that were selected on norfloxacin or ofloxacin contained a C-to-T transition in the gyrA QRDR, leading to substitution of Ser-83 by Leu in the GyrA protein. Analysis of the sequence of the gyrB QRDR of the eight multistep-selected mutants did not reveal any difference compared to that of the gyrB QRDR of the reference strain M. hominis PG21. Similar analyses of eight one-step-selected mutants did not reveal any base change in the gyrA and gyrB QRDRs. These results suggest that in M. hominis, like in other bacterial species, a gyrA mutation at Ser-83 is associated with fluoroquinolone resistance.

Amino Acid Sequence↗
PubMed1997

[Urogenital infections linked to Chlamydia and mycoplasmas].

Chlamydia trachomatis is responsible for urogenital infections, often minimally symptomatic, revealed by their complications. Mycoplasmas, mainly Ureaplasma urealyticum and Mycoplasma hominis, are normal commensal organisms of the genital tract, which sometimes makes it difficult to determine their pathogenicity. However, they are responsible for urogenital infections, and U. urealyticum is a pathogen in male urethris. The laboratory diagnosis is based on specific techniques adapted to these microorganisms. In the case of C. trachomatis, it has benefited from the recent progress in molecular biology techniques. The therapeutic approach is common to both types of organisms: tetracyclines and macrolides are the major antibiotics used in the treatment of these urogenital infections.

Anti-Bacterial Agents↗
PubMed1997

[Comparative in vitro activity of cefepime: multicenter study in Aquitaine].

Over a 6 month-period (1st January to 30th June 1995), the results of antibiotic susceptibility testing routinely performed for beta-lactams against enterobacteria, Pseudomonas aeruginosa, and Acinetobacter in 7 laboratory hospitals of Aquitaine, have been collected and divided in susceptibility profiles. A total of 9269 strains (7323 enterobacteria, 1667 P. aeruginosa, 279 Acinetobacter) have been examined. On the whole, cefepime (91,5%) and ceftazidime (91,7%) were the most active cephalosporins, followed by cefpirome (87,9%) and cefotaxime (80,4%); imipenem was the most active beta-lactam agent (97,4%). When the strains were divided according to their susceptibility profiles, the advantage of cefepime was shown to be related to its excellent activity against enterobacteria: all strains susceptible to cefotaxime and ceftazidime (CTX/CAZ-S) were susceptible to cefepime, as were most of the strains with an intermediate susceptibility or resistant to these drugs (CTX/CAZ-I/R, approximately 5% of the enterobacteria). The latter strains exhibited a phenotype corresponding either to the overproduction of their chromosomal cephalosporinase (approximately 20% of the species belonging to group 3) or to the synthesis of an extended spectrum beta-lactamase (19% of the strains of Klebsiella pneumoniae). Cefepime was active against 93% of the derepressed mutants of enterobacteria, including 3 imipenem resistant isolates of Enterobacter. CAZ-S strains of P. aeruginosa (84%) were usually susceptible to cefepime (80%), as were 6% of the CAZ-I/R strains. CAZ-S strains of A. baumannii (16.3%) were generally susceptible to cefepime (83%), as were 3.2% of the CAZ-I/R strains.

Acinetobacter↗