Prognostic factors in adult community-acquired bacterial meningitis: a 4-year retrospective study

The aim of this 4-year, observational, single-center study was to identify prognostic factors and evaluate the need for intensive care in cases of bacterial meningitis. During the study period, 60 cases of adult bacterial meningitis were identified. Fifty-one patients were transferred to the intensive care unit at various times during their hospital stay. In the multivariate analysis, factors significantly associated with the need for mechanical ventilation and/or vasopressive drugs included comorbidity and a Glasgow coma score of less than 12 at hour 6 following presentation. The results indicate patients with a decreased level of consciousness, neurological deficit or comorbidity should be admitted to the intensive care unit at an early stage of illness. When patients lack these criteria 6 h following presentation, admission to the medical ward is reasonable.

Synthesis and antimycobacterial activity of ferrocenyl ethambutol analogues and ferrocenyl diamines

A new series of ferrocenyl diamino alcohols and diamines were synthesized and their inhibitory potencies were probed with Mycobacterium tuberculosis. Interestingly, ferrocenyl diamines 6a and b display significant activities against M. tuberculosis H37Rv.

Screening of volunteer students in Yaounde (Cameroon, Central Africa) for Chlamydia trachomatis infection and genotyping of isolated C. trachomatis strains

The prevalence of Chlamydia trachomatis infection was 3.78% out of 1,277 volunteer students screened by direct fluorescence assay and Cobas Amplicor PCR. The infection was associated with the nonuse or inconsistent use of condoms in women (P = 0.026) and a previous sexually transmitted infection in men (P = 0.023). The most frequent genotypes determined by sequencing the omp1 genes of 25 clinical isolates were E (44%) and F (20%), and some strains harbored mutations, but E genotype strains did not.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

[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.

[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.

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.

Epidemiological study of an outbreak due to multidrug-resistant Enterobacter aerogenes in a medical intensive care unit

In 1993, 63 isolates of Enterobacter aerogenes were collected from 41 patients in a medical intensive care unit (ICU). During the same period, only 46 isolates from 32 patients were collected in the rest of the hospital. All isolates were analyzed by antibiotic resistance phenotype, and 77 representative isolates were differentiated by plasmid restriction analysis, ribotyping, and arbitrarily primed (AP)-PCR. The extended-spectrum beta-lactamases produced by 22 strains were characterized by determination of their isoelectric points and by hybridization of plasmid DNA with specific probes. The isolates were divided into 25 antibiotic resistance phenotypes, either susceptible (group I) or resistant (group II) to aminoglycosides, and exhibited three phenotypes of resistance to beta-lactams: chromosomally derepressed cephalosporinase alone or associated with either extended-spectrum beta-lactamases (mainly of the SHV-4 type) or imipenem resistance. The results of the tests divided the 77 representative isolates (group I, n = 21; group II, n = 56) into 15 plasmid profiles, 14 ribotypes, and 15 AP-PCR patterns. Although the resistant isolates (group II) exhibited different plasmid profiles, ribotyping and AP-PCR analysis demonstrated an identical chromosomal pattern, indicating an epidemiological relatedness. They were mainly found in the medical ICU and occasionally in other units. The susceptible strains (group I) had various and distinct markers and were mainly isolated in units other than the medical ICU. In conclusion, the presence of a nosocomial outbreak in an ICU and the spread of a multidrug-resistant epidemic strain throughout the hospital was confirmed. Ribotyping and AP-PCR represent discriminatory tools for the investigation of nosocomial outbreaks caused by E. aerogenes.

[Molecular typing by pulsed field gel electrophoresis of Stenotrophomonas maltophilia isolated in a department of hematology]

Stenotrophomonas maltophilia is an important nosocomial pathogen. The increased isolates of S. maltophilia among hematology unit patients led to an epidemiological survey. Over 26 months, 24 strains isolated from 23 patients and an environmental isolate from blood pressure armband have been identified. The isolated were first analysed by the use of phenotypical markers: biotype, antibiotic susceptibility, but the minor differences observed justified a genotypic analysis. Pulsed field gel electrophoresis of genomic DNA was carried with XbaI and DraI restriction endonucleases by contour-clamped homogeneous electric field method (CHEF). The data obtained showed a great genomic diversity within the species S. maltophilia. Nevertheless, the same restriction profile was found for 3 patients and 3 other profiles were obtained for 3 couples of patients hospitalized at the same time. All the other strains isolated from subjects hospitalized during the same period exhibited pulsotypes independent from each other. Compared to biotypes and antibiotic susceptibility, these results indicate field only with non modified primers, and the absence of 460 mutations was confirmed by sequencing. Two isolates P1 and P2, from a transplanted patient were amplified with both primers MCMM and MCMW: sequencing analysis shown the presence of a mixture of strains, one of them harbouring A- > G 1378 mutation. One resistant strain was amplified neither with MCMM nor with MCMW: a C- > T silent mutation at nt 1368 was present. As sequencing analysis confirmed PCR results, discriminative PCR enables isolates to be rapidly assessed for the presence or absence of 460 mutations. Moreover, it can distinguish Met to Val from Met to Ile mutations, and allows the analysis of mixtures of sensitive and resistant strains.

[In vitro activity of a new quinolone, NM 394, against Chlamydia trachomatis]

A study of antimicrobial susceptibility of Chlamydia trachomatis was performed with a new quinolone, NM 394 (Laboratoire Dr. Bouchara). Ten C. trachomatis strains of four different genovars (3G, 4E, 2D, IDv) were grown in confluent McCoy cells on coverslips in multidishes (24 wells). For each C. trachomatis strain, two multidishes were prepared, one for MIC, one for MBC. Three inoculum titrated from 100 to 10000 IFU/ml were inoculated into wells. After incubation 48 h at 37 degrees C, the cultures were fixed in methanol and examined for inclusions after staining with fluorescein-conjugated anti-Chlamydia antibody. The MIC was defined as the lowest antibiotic concentration at which no inclusion formation was observed. For the determination of MBC, the culture media was replaced with sucrose phosphate buffer (2SP) and the cultures were incubated without antibiotic for 48 h and stained. The MBC was the lowest antibiotic concentration at which no inclusion formation was observed after one passage without antibiotic. The increase of the inoculum from 10(3) to 10(5) IFU/ml did not affect significantly the activity of NM 394. All strains were inhibited by 16 mg/l of NM 394. The IC 50 and 90 were 2 and 8 mg/l respectively. The MIC and the MBC values were similar.

Epidemiological study of an outbreak of infection with Staphylococcus aureus resistant to lincosamides and streptogramin A in a French hospital

A significant increase in the incidence of isolates of methicillin-resistant Staphylococcus aureus (MRSA), that were also resistant to lincosamides and streptogramin A (LSA-MRSA), was observed in a French university hospital. Twenty-seven isolates from the outbreak were characterised, including 17 isolates from a plastic surgery ward and six control strains of MRSA. The strains were examined by antibiotyping and biotyping, and by three molecular methods: plasmid analysis, ribotyping and insertion sequence (IS) typing with IS256 sequence as a probe. Antibiotyping (five antibiotypes) was discriminatory because of the uncommon resistance phenotype of the epidemic strain. Biotyping (three biotypes), DNA plasmid analysis (four profiles) and ribotyping (two profiles) were poorly sensitive, in contrast to IS-typing (12 profiles). By the latter method, a coefficient of similarity (percentage similarity) compared to the predominant IS profile was calculated. Strains with a coefficient of similarity > or = to 82% were considered as highly related to the epidemic strain, while those with a coefficient of similarity < or = to 40% were regarded as distant. Results obtained with the five markers confirmed that an outbreak of hospital infection had occurred in the plastic surgery ward, with spread of the epidemic strain throughout the hospital.

Epidemiologic and molecular investigations of genital mycoplasmas from women and neonates at delivery

The rates of colonization by Ureaplasma urealyticum and Mycoplasma hominis were evaluated in 208 women at delivery and in their neonates. Mycoplasmas were isolated from the cervicovaginal specimens of 100 mothers (48.1%) and from the gastric secretions of 40 neonates (19.2%). The prevalences of U. urealyticum and M. hominis were 47.6% and 11.0% in women and 19.2% and 1.0% in neonates, respectively. Premature rupture of membranes was significantly associated with colonization of women by U. urealyticum (P = 0.031), and colonization of their neonates by U. urealyticum (P = 0.002) and/or M. hominis (P = 0.023). Forty-four selected strains of mycoplasmas were further characterized by arbitrarily primed polymerase chain reaction. All strains of U. urealyticum belonged to the parvo biovar of the species. Arbitrarily primed polymerase chain reaction demonstrated the similarity of strains isolated from mother-neonate pairs, confirming the importance of vertical transmission of mycoplasmas at delivery.

[Molecular typing by pulsed field gel electrophoresis of Pseudomonas (Burkholderia) cepacia isolated from a nosocomial infection]

Because of the emergence of Pseudomonas (Burkholderia) cepacia, isolated among patients from an intensive care unit of the Hôpital Pellegrin (Bordeaux), strains were studied in the aim to determine the source and the mode of transmission of the bacteria. The study was performed on 44 isolates of P. cepacia from 21 patients (23 strains) or from the environment (16 isolates from ventilators and five from the distilled water used for these ventilators). Susceptibility to 23 antibiotics of these strains and endonuclease restriction polymorphism on their total DNA were determined. Pulsed field gel electrophoresis was performed after digestion of the genomic DNA, using three restriction enzymes. Results obtained by analysis of genotypic characteristics demonstrated the clonal origin of the P. cepacia epidemy in the different intensive care units, but did not localize the source of the infection.

Genetic variability among Chlamydia trachomatis reference and clinical strains analyzed by pulsed-field gel electrophoresis

Pulsed-field gel electrophoresis (PFGE) was applied to Chlamydia trachomatis reference strains representing each of the 18 serovars and to 29 clinical isolates from genital specimens collected in Bordeaux, France, or Malmö, Sweden. Comparison of the fingerprint patterns of the reference strains revealed a high level of polymorphism of the total DNA when SmaI was used (14 profiles), whereas the other enzymes, Sse8387I and ApaI, showed fewer differences. Some serovars, considered to be closely related on the basis of their antigenic determinants located on the major outer membrane protein (MOMP), such as D and Da or I and Ia, were shown to be different after PFGE of their genomic DNAs. However, serovars B and Ba and serovars L2 and L2a had identical patterns after analysis with the three endonucleases. When applied to clinical isolates, which were typed by restriction fragment length polymorphism analysis of the MOMP gene, PFGE allowed the detection of intragenotype polymorphisms and showed the identity of two strains successively isolated from the same patient. This technique seems to be an efficient tool for epidemiological studies when used in addition to serotyping or genotyping by restriction fragment length polymorphism analysis of the MOMP gene.

[In situ hybridization of cells infected by Chlamydia trachomatis]

Hybridization in situ of chlamydia trachomatis allows identification of the bacteria. Moreover exact chlamydia trachomatis localization at tissue level can be demonstrated. It seems to us very important to know for instance in conjunctiva were chlamydia trachomatis are located. We used DNA DIGOXIGENIN labelled plasmidic probe of 503 b.p. Detection of chlamydia trachomatis on paraffin embedded cells becomes possible. Specificity is 100% as plasmidic sequence is not found in other bacteria. Sensitivity seems to be good quality on experimental model. At present time, it is under clinical evaluation. This method could complete PCR for chlamydia detection in case of controversial diagnosis.

Evaluation of molecular typing for epidemiological study of Chlamydia trachomatis genital infections

Molecular typing and serotyping were compared for 150 Chlamydia trachomatis strains isolated from genital sources, belonging to 10 different serovars. Because of the general agreement of the two methods, molecular omp1 genotyping was applied to the epidemiological study of C. trachomatis isolates from genital infections in Bordeaux (France), during a 29-month period. The most prevalent omp1 genotypes were E (51.7%), F (17.3%), D (8.8%), and G (8.4%). Restriction enzyme analysis allowed identification of a serovar D variant (Dv), whereas serovar E strains were homogeneous.

Polymerase chain reaction using 16S rRNA gene sequences distinguishes the two biovars of Ureaplasma urealyticum

Several fundamental phenotypic and genotypic differences have separated strains of the genital mycoplasma Ureaplasma urealyticum into two clusters or biovars. However, the lack of an easily performed and unambiguous test to discriminate between them has hampered investigation of the relationship between these biovars and disease. We determined the 16S rRNA nucleotide sequence of U. urealyticum 27, the serovar 3 standard and representative of the parvo biovar (serovars 1, 3, 6, and 14). This sequence was compared with the published sequence of U. urealyticum T960, which is the type strain and the serovar 8 standard and is representative of the T960 biovar which is composed of the 10 intervening serovars. Homology between the two sequences was 98.8%; differences were exploited to provide primers for biovar-specific polymerase chain reactions (PCRs). The results of these reactions placed all 14 serovar standard strains into the correct biovar. The PCRs were also applied to 10 cloned and 8 noncloned isolates that had been serotyped earlier. For 16 of them, we deduced their biovars from the serotyping data and then confirmed them by PCR. One unpredictable isolate and one nonserotypeable isolate were also classified as to biovar. Thus, we have developed a method for biotyping U. urealyticum that is applicable to both laboratory-adapted strains and wild-type isolates and that is appropriate for testing large numbers of clinical isolates. The amplification by the T960 biovar PCR protocol of DNAs from ureaplasmas of animals and certain Mycoplasma species suggested that the parvo biovar has diverged from the mainstream of the evolution of this clade.

[In vitro activity of sparfloxacin against mycoplasmas]

The in vitro activity of the new difluorinated quinolone sparfloxacin against mycoplasmas was studied comparatively with ofloxacin, doxycycline, and erythromycin. Minimal inhibitory concentrations (MICs) were determined by agar dilution for 21 strains of Mycoplasma pneumoniae (Mp), 20 strains of M. hominis (Mh), 7 strains of M. genitalium (Mg), and 3 strains of M. fermentans (Mf), and by broth dilution for 49 strains of Ureaplasma urealyticum (Uu). Sparfloxacin was very active against all tested mycoplasmas, with the following MICs (microgram/ml): 0.1 for Mp, 0.05-0.1 for Mg, less than or equal to 0.01 for Mh, less than or equal to 0.01-0.05 for Mf, and 0.1-0.5 for Uu. Minimal bactericidal concentration was 1 microgram/ml for Uu. Sparfloxacin was more active than ofloxacin against all the mycoplasmas tested and was the most active compound against Mh and Mf. Erythromycin had the lowest MICs against Mp and Mg. Sparfloxacin exhibited comparable effectiveness against doxycycline-susceptible and doxycycline-resistant strains. Sparfloxacin appears to be one of the most active agents in vitro against mycoplasmas.

In vitro susceptibilities of Mycoplasma genitalium to antibiotics

The susceptibilities of seven clinical isolates of Mycoplasma genitalium and three strains of Mycoplasma pneumoniae to a variety of antibiotics were examined by an agar dilution method. Macrolides, pristinamycin, and tetracyclines were very active against both species. Sparfloxacin was the most active quinolone tested. None of the 21 antibiotics tested had differential activity toward the two organisms.

Isolation of genital mycoplasmas from blood of febrile obstetrical-gynecologic patients and neonates

In a prospective study, 1156 blood specimens collected from hospitalized febrile obstetrical-gynecologic patients and neonates with suspected sepsis, were inoculated into a conventional biphasic culture medium, Castaneda S and cultures incubated aerobically. 15-24 h later the broth cultures were subcultured to specific media for detection of mycoplasmas. Genital mycoplasmas were isolated in 15 samples (taken from 8 women) and in 2 from 1 neonate. Mycoplasmas and members of the family Enterobacteriaceae were the most frequent significant bacteria isolated from adult specimens. Mycoplasma isolations were associated with either postpartum or postabortum febrile infections in women. Four of the neonates, whose mothers were infected, showed respiratory distress at birth; 1 of them had mycoplasmas in the blood. All febrile states in obstetrical or gynecological patients, and in neonates, should routinely lead to blood cultures for detection of mycoplasmas and ureaplasmas.

Typing of Chlamydia trachomatis by restriction endonuclease analysis of the amplified major outer membrane protein gene

A procedure was developed for characterization of Chlamydia trachomatis strains by using restriction endonuclease analysis of amplified genes of the major outer membrane protein (MOMP). Reference strains of the 15 serovars (A through K and L1 through L3) and clinical isolates were tested. The nucleotide sequences of the MOMP genes of each of the 15 serovars were arbitrarily constructed by using the sequences of the four variable domains known for each serovar and the constant domains of serovar L1. Computer analysis of these sequences indicated that two restriction digestions performed in parallel, one with AluI and the other with IIpaII, followed by HinfI and EcoRI, would allow the theoretical differentiation of 13 serovars. Serovars Ba and L1 presented the same theoretical restriction profile. Our typing method consisted of polymerase chain reaction amplification of a fragment of about 1,200 bp of the MOMP gene, followed by restriction endonuclease digestion with the aforementioned enzymes. From the 15 serovars, we obtained 14 different patterns; 13 profiles were serovar specific, while serovars B and Ba presented the same pattern. Application of this typing method to C. trachomatis strains isolated from clinical material gave the same results as the immunotyping method for 14 of 17 strains. Furthermore, restriction endonuclease analysis detected differences within a serovar. This method seems to be promising for epidemiological studies.

Evaluation of AN-Ident

AN-Ident (Analytab Products, Inc., Plainview, N.Y.) is a ready-to-use system for anaerobe identification. It is based on the detection of constitutive preformed enzymes, is growth independent, and requires only 4 h of aerobic incubation. This micromethod was evaluated for its ability to identify anaerobic bacteria by using a conventional methodology as a reference. Of 265 clinical isolates, AN-Ident accurately identified 241 (91%) of the isolates to the species level and 259 (98%) of the isolates to the genus level, with limited supplemental testing needed (5%). The AN-Ident system performed well for the most common pathogens but less satisfactorily for infrequently isolated and/or asaccharolytic species; expansion and updating of the data base would be helpful. Although some color reactions were difficult to interpret, the commercial kit was easy to use.

[Evaluation of the Mycoplasma Plus and the SIR Mycoplasma kits for quantitative detection and antibiotic susceptibility testing of genital mycoplasma]

We compared the results obtained with two commercially available systems (Diagnostics Pasteur) for the quantitative identification and the antibiotic susceptibility testing of the genital mycoplasmas. Ureaplasma urealyticum and Mycoplasma hominis with established methodologies, i.e. isolation on agar with enumeration by dilutions in broth medium and MIC determinations. The Mycoplasma Plus system, consisting of six cups, was designed for the identification and quantitation of genital mycoplasmas and the detection of yeasts. Used in parallel in 150 clinical specimens, it detected U. urealyticum in 42 out of 43 and M. hominis in 10 out of 11 specimens positive by the established methodology. The SIR Mycoplasma antibiogram, consisting of 16 cups, provided for the testing of 1 or 2 concentrations (micrograms/ml) of each of 8 antibiotics: doxycycline, minocycline and lymecycline (4-8); erythromycin (1-4); josamycin (2-8); clindamycin (2); pristinamycin (2); and ofloxacin (1-4). Using an inoculum of about 10(4)-10(5) organisms/ml, we found that major part of the results was in accord with those obtained with the MIC determined in broth for U. urealyticum and on agar for M. hominis. Strains intermediate or resistant to the tetracyclines were identified. Both systems seemed suitable for clinical laboratory use.

Benzoxazinone kanamycin A conjugate. A new fluorescent probe suitable to detect mycoplasmas in cell culture

The synthesis of a new benzoxazinone derivative suitable to detect early infection of cultured cells with mycoplasmas is described. p-[beta-(7-dimethylamino 1,4-benzoxazin 2-one 3yl)-vinyl]- phenylpropenoic acid was coupled to kanamycin A, an aminoglycoside leading to a cationic fluorescent probe which fluoresces at 600 nm upon excitation at 490 nm. This fluorescent probe is shown to heavily label the glycocallix of all the mycoplasma strains tested which are found to be associated with contaminated cultured cells and to allow an easy and rapid detection of contamination by fluorescence microscopy and flow cytometry.

[Actinobacillus ureae meningitis. Apropos of a case]

A case of Actinobacillus ureae meningitis in a 52 year old man with an history of chronic sinusitis and previous skull fractures is reported. Actinobacillus ureae, called for a long time Pasteurella ureae, is a rare cause of meningitis as shown by a short review of the literature (eight cases reported). We have searched the bacteria in the rhinopharynx of the patient's four dogs: this search was unsuccessful in agreement with the literature data which has not yet established an animal host for Actinobacillus ureae.