Prosthetic joint infection caused by Tropheryma whippelii (Whipple's bacillus).
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Biomedical subjects
Publications and source records attributed to A Ros.
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Arbitrarily primed PCR with two different primers was compared with ribotyping and monoclonal antibody analysis for typing Legionella strains. Applied to 11 epidemiologically unrelated strains, arbitrarily primed PCR resulted in an index of discrimination of 100% with both primers. It was found able to identify an epidemic clone of Legionella pneumophila serogroup 1 that was isolated from both patients and a hot water circuit of the same hospital.
OBJECTIVE: To study the spread of strains of Enterobacter aerogenes in our hospital in 1992 and 1993 by using two genotypic markers, and to evaluate these methods for the epidemiological investigation of this species. DESIGN: Ribotyping (using two endonucleases) and arbitrarily primed (AP)-PCR (using two different 10-mer primers) were applied to the epidemiological typing of clinical strains of E aerogenes isolated from hospitalized patients. SETTING AND PATIENTS: The intensive care unit (ICU; 5 patients, 13 isolates), nephrology units (3 patients, 5 isolates), and surgery units (2 patients, 2 isolates) of the university hospital of Saint-Etienne (France). RESULTS: Eight epidemiologically unrelated isolates, chosen as controls, exhibited distinct profiles, both by AP-PCR and ribotyping. Two clones of E aerogenes circulated in the ICU; both were isolated successively from samples of a single patient who stayed in the unit for almost 1 year. A third clone was recovered from patients of surgery units. A fourth clone was shown to have infected patients of nephrology units. CONCLUSIONS: Ribotyping and AP-PCR appear to be reliable methods for typing E aerogenes strains implicated in nosocomial infection. The spread of independent clones of E aerogenes in different units of our hospital in 1992 and 1993 was demonstrated by both methods. This study emphasizes the need to choose the endonucleases or primers with care to obtain high discriminatory results in genotypic investigations.
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The genotypic diversity of 40 presumably epidemiologically unrelated strains of Pseudomonas aeruginosa belonging to nine different O-serotypes was analysed according to ribosomal DNA fingerprints. Ribotyping was performed with a digoxigenin-labelled DNA probe and four restriction endonucleases. Characteristic banding patterns of three to 12 bands were obtained with the different endonucleases. Among the 40 strains, eight, nine, 10 and 29 different ribotypes were differentiated with EcoRI, the combination EcoRI+HindIII, BamHI and PvuII, respectively. Poor correlations were noted between the results of serotyping and those of ribotyping. With the latter method, indices of discrimination were calculated for each enzyme from the data of the 40 unrelated strains: the values ranged from 0.678 for EcoRI to 0.979 for PvuII. Epidemiologically related samples were also tested; this enabled assessment of whether the method was able to cluster strains from a common origin with each of the enzymes tested. Ribotyping with PvuII endonuclease is proposed for screening large numbers of P. aeruginosa strains in epidemiological studies. Additional enzymes could be used to further increase the discrimination between isolates found to be indistinguishable with PvuII enzyme.
In December 1992, Enterobacter cloacae was isolated from the oropharynx and respiratory tract of six ventilated neonates hospitalized in the intensive care unit (ICU) of our hospital. To establish the spread of the outbreak, 41 strains of E. cloacae were analyzed for genotypic markers by three methods: plasmid profile analysis, ribotyping with EcoRI or PvuII endonuclease, and arbitrarily primed (AP) PCR. The tested strains included 12 isolates from the 6 epidemic cases, 4 isolates from the respiratory tract of 4 children hospitalized in other wards during the same period, 13 isolates from 12 children hospitalized in pediatric units before or after the outbreak, and 12 epidemiologically unrelated isolates. Ribotyping and AP PCR demonstrated that each of the last 12 strains exhibited distinct genomic patterns, as did each of the strains isolated from neonates hospitalized before or after the epidemic peak. Conversely, two clones of strains were found among the isolates recovered in December, with concordant results being obtained by the three typing methods: the first clone included seven strains from five ventilated children in the ICU and two children from another ward; another clone was shared by one neonate in the ICU and an infant from another ward. These results indicate that ribotyping and AP PCR-the latter applied, to our knowledge, for the first time to the genotypic analysis of E. cloacae--represent very discriminatory tools for the investigation of nosocomial outbreaks caused by this species.
The spread in Europe of a single multiresistant strain of Pseudomonas aeruginosa serotype O12 has been suggested. This bacterium was responsible for a nosocomial outbreak in our hospital in 1988-1989. Three different epidemiological methods were used to analyze 30 strains isolated during five consecutive years. Protein profile analysis and chromosomal DNA fingerprinting with four different enzymes revealed closely related patterns. rRNA gene restriction fragment length analysis performed with a digoxigenin-labelled probe showed identical hybridization patterns with four to six bands according to the endonuclease used. Combination of the three typing methods showed genotypic homogeneity of these Pseudomonas aeruginosa O12 strains, despite a relative increase in their antibiotic resistance.
A prospective study was undertaken to determine the source of Pseudomonas cepacia colonization and infection that had affected ventilated patients in an Intensive Care Unit (ICU) for three years. Thirty-eight patients undergoing mechanical ventilation were enrolled during a six-week period. Samples were taken from patients, ventilator circuits and the environment for culture. P. cepacia was isolated from the condensate formed in the ventilator circuit and the source of the contamination was shown to be the temperature sensor. Ribotyping of the representative strains of P. cepacia performed with two endonucleases, EcoRI and PvuII, confirmed the homogeneity of the isolates from patients and ventilator circuits. A modification of the procedure for disinfection of the temperature sensors resulted in the eradication of P. cepacia from the ICU.
Chronic microaspiration through a tracheal cuff is the main culprit in the penetration and colonization of the lower respiratory tract. A total of 145 patients intubated for more than 3 days were randomly assigned to a double nosocomial pneumonia (NP) prevention: 1--Prevention of aspiration by hourly subglottic secretion drainage (SSD) with a specific endotracheal tube (HI-LO Evac tube, Mallinckrodt); 2--Prevention of gastric colonization using either sucralfate or antacids. Four random groups were defined, similar in age and severity of illness. Subglottic secretion drainage treatment was associated with: a) a twice lower incidence of NP (no-SSD: 29.1%, SSD: 13%); b) a prolonged time of onset of NP (no-SSD: 8.3 +/- 5 days, SSD: 16.2 +/- 11 days); c) a decrease in the colonization rate from admission to end-point day in tracheal aspirates (no-SSD: +21.3%, SSD: +6.6%) and in subglottic secretions (no-SSD: +33.4%, SSD: +2.1%). Sucralfate was not associated with a significantly lower incidence of NP (antacids: 23.6%, sucralfate: 17.8%), but with a lower increase in the colonization rate in subglottic and gastric aspirates, from admission to end-point day.
Four methods for rapid detection of adenovirus were evaluated by testing retrospectively 28 frozen clinical specimens from which an adenovirus strain had been isolated. After thawing all specimens were retested for the presence of adenovirus by conventional culture on KB cells and found to be positive. The four tests used for rapid detection of adenovirus were a 48-hour culture technique, and an immunoassay, a latex agglutination test and an immunofluorescence assay for direct detection of viral antigen using commercially available reagents. Of the 28 specimens all were positive in the 48-hour culture, 25 (89%) positive in the immunoassay and 10 (36%) positive in the latex agglutination test. Six of eight nasopharyngeal aspirate specimens were positive in the immunofluorescence assay. Twenty-five clinical specimens negative for adenovirus on conventional culture were also negative in the 48-hour culture technique. Overall, the rapid (48-hour) culture technique was 100% sensitive and 100% specific compared to conventional culture. The direct detection of viral antigen by immunoassay was less sensitive, however results were available within a few hours. Prospective comparative studies are warranted to determine whether these rapid techniques could replace conventional culture in the routine diagnosis of adenovirus infection.
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Cellular receptors play an important role in viral pathogenesis. Until now little was known on echovirus (EV) receptor. Using detergent-treated KB cell extracts as immunogen, a mouse monoclonal antibody (Mab 143) was produced that selectively blocks the attachment of EV-11 to KB and other susceptible cells. By immunoblotting, Mab 143 detected a 44,000 protein on susceptible cell lines but not on cell lines from nonprimate origin. The receptor protein complex, purified from KB cell membranes by immunoaffinity using Mab 143 as ligand, was shown to contain a single glycoprotein with apparent molecular weight of 44,000 (gp44). The role of gp44 in the attachment of EV-11 onto KB cells was demonstrated by the ability (i) of affinity-purified gp44 to reduce the infectivity of EV-11 and (ii) of rabbit polyclonal antisera raised against gp44 to protect cells from the replication of various EV, as did Mab 143.
A panel of 68 serum specimens from 41 subjects exhibiting various immunological patterns to Mycoplasma pneumoniae as determined by detection of a 180 kDa protein in immunoblotting was used to compare five commercially available tests based on different methods: complement fixation test (CFT), microparticle agglutination (MAG), indirect immunofluorescence assay (IFA), enzyme-linked immunosorbent assay (Elisa), and latex agglutination (LA). The tests were performed according to the manufacturers' instructions. For the determination of immunity to M pneumoniae, the five tests were in good accordance with immunoblotting: sensitivity was 100% for all the five assays, specificity ranged from 95.6% (MAG) to 82.6% (Elisa) and overall agreement ranged from 98.2% (MAG) to 92.8% (Elisa). The comparisons of antibody rates obtained by the four quantitative tests (CFT, MAG, IFA, Elisa) showed correlation coefficients ranging from 0.87 (CFT-IFA) to 0.67 (CFT-Elisa). Six significant antibody rises demonstrated by immunoblotting patterns were detected by all the tests but Elisa in one case. As a whole, the commercial assays gave satisfactory results for routine determination of immune status to M pneumoniae: CFT was the cheapest test and MAG and LA were the easiest to perform.
The serum kinetics of vancomycin was studied in two patients aged 3 and 15 years during antibiotic therapy for catheter related sepsis associated with Staphylococcus epidermidis. Vancomycin was administered, simultaneously, by parenteral conventional doses (30 mg/kg/day div q 8 h) and using the antibiotic-lock technique in the infected catheter at a high concentration (150 mg/ml) during one hour, 3 hours after each infusion. Pharmacokinetics data did not show any significant change in the serum kinetics of the antibiotic. The results suggest that delivering a high concentration of vancomycin in the infected catheter using the lock technique may be useful to sterilize infected catheter without toxic effect.
Paired serum specimens from 24 patients with echovirus (EV) type 4 infection by virus isolation were tested by the immunoblot technique for the presence of IgG, IgM, and IgA antibodies to EV4 structural proteins. Single sera from 20 patients without neutralizing enterovirus IgM were used as controls. All the sera from EV4-infected patients had IgG antibodies to VP1 of EV4 but also 13 out of the 20 controls. 23 out of 24 EV4-infected patients elicited IgM and IgA specific antibodies to VP1, a pattern highly significant as compared with controls (3/20 for IgM and 8/20 for IgA). In 16 out of the 24 EV4-infected patients, the IgM antibodies were also directed against VP2 (versus 2 out of 20 in the control group). Anti-VP2 IgA were detected in 4 out of the 24 EV4 patients (versus 0 in controls). The 24 paired sera from EV4-infected subjects were also tested by immunoblot technique against three other enteroviruses: EV21, coxsackievirus A9 and poliovirus 1. Cross-reactivities were observed to a large extent against VP1 and VP2 proteins with the three classes of antibodies. These results confirm the data of previous studies on the reactivity of IgM antibodies to various structural proteins that IgG antibodies react exclusively to VP1. Furthermore, this study demonstrates the occurrence of circulating IgA antibodies directed to VP1 and sometimes VP2 in the course of enterovirus infection. The potential interest of this latter finding for diagnosis requires further investigation.
Falls are a leading cause of death from injury among older persons in the United States, and about one in three older persons falls each year. Yet, reliable estimates of the incidence of fall injury events in a population-based setting are not readily available. Therefore, the authors analyzed population-based surveillance data, between July 1985 and June 1987, from the Study to Assess Falls Among the Elderly, Miami Beach, Florida. The rate of fall injury events coming to acute medical attention increased exponentially with age for both elderly men and women (predominantly white), reaching a high for those aged 85 years or more of 138.5 per 1,000 for males and 158.8 per 1,000 for females. Compared with males, females had a higher incidence of fractures other than skull. Males were nearly twice as likely to die, however, following a fall injury event than were females. Of those fall injury events identified through the surveillance system, about 42% resulted in hospital admission. The mean length of hospital stay was 11.6 days overall and was 15.5 days for hip fracture, 9.8 days for skull fracture/intracranial injury, 11.2 days for all other fractures, and 9.1 days for all other injuries. About 50% of fall injury events that occurred at home and required hospital admission resulted in a person being discharged to a nursing home.
Data are presented of IgM detection by a neutralization test used routinely in 1,062 patients. Antigens isolated during the period of investigation were EV4, EV7, EV11, EV18, EV21, EV24, EV33, CA9, CB2, CB4, and CB5. No difference was observed in the distribution of IgM-positive sera according to age and sex. Total antibodies are at higher titres when IgM antibodies are present. Polytypic IgM responses are not frequent (less than 10%). The frequency of the IgM-positive sera for a given serotype correlated with the frequency of isolates for the serotype except for CA9. Other than for babies under age 6 months, IgM detection is more frequent than is isolation. The susceptibility of the elderly and the frequency of IgM-positive sera among adults over age 40 years suggests possible underestimation of enterovirus infections in adults. The duration of IgM remains a major question.
A total of 314 patients exhibiting symptoms consistent with a viral disease provided, during the early stage of hospitalization, at least one specimen from a peripheral site (throat or stools or both) and a serum specimen in order to evaluate the neutralizing immunoglobulin M (IgM) antibody response in acute-phase serum in comparison with virus isolation for the rapid diagnosis of enterovirus (EV) infection. IgM antibodies were fractionated by ion-exchange chromatography and tested by seroneutralization against the various types of EV that have been recently circulating. A total of 189 patients (60%) were negative, and 21 (7%) were positive by both methods; in 51 patients (16%), a virus was isolated without IgM antibody response; 53 patients (17%) showed the opposite pattern. In all age groups except for children under 6 months, the frequency of positive results was higher with IgM serology than with virus isolation (27 and 22%, respectively). Apart from meningitis, for which isolation was more efficient, the other clinical conditions were associated with similar percentages of positivity by both methods. Regarding the 21 cases with positive results by the two techniques, the same serotype was detected in 9 cases and different serotypes were detected in 12, suggesting crossreactivities. Thus, IgM neutralizing antibody response on acute-phase serum appears to be of limited value in the rapid diagnosis of acute EV infection but may prove useful for the investigation of the wide range of chronic diseases associated with EV.