Sentinel-site surveillance of Mycobacterium avium complex pulmonary disease

The incidence of Mycobacterium avium complex (MAC) pulmonary disease in HIV-negative patients was studied prospectively from January 1, 2000 to December 31, 2002 through 32 sentinel sites distributed all over France. Among the 275 patients who yielded MAC isolates from respiratory clinical specimens, 101 (36.7%) met the bacteriological, radiographical and clinical criteria established by the American Thoracic Society for nontuberculous mycobacterial respiratory disease. Of these 101 patients, 81 had underlying lung disease, mainly previous tuberculosis, bronchectasis or chronic obstructive pulmonary disease. Among the 20 patients with no underlying lung disease, 12 had a predisposing factor such as leukaemia or immunosuppressive treatment and eight had no predisposing factor. All patients with MAC respiratory disease had clinical symptoms, commonly cough and fatigue, and 52 (51.5%) were sputum smear positive for acid-fast bacillus. The ratio of patients with Mycobacterium avium complex pulmonary disease to patients with pulmonary tuberculosis in France was estimated to be 3% and the incidence of Mycobacterium avium complex pulmonary disease in France was 0.2 per 100,000 inhabitants.

Efficacy of the combination rifampin-streptomycin in preventing growth of Mycobacterium ulcerans in early lesions of Buruli ulcer in humans

Mycobacterium ulcerans disease is common in some humid tropical areas, particularly in parts of West Africa, and current management is by surgical excision of skin lesions ranging from early nodules to extensive ulcers (Buruli ulcer). Antibiotic therapy would be more accessible to patients in areas of Buruli ulcer endemicity. We report a study of the efficacy of antibiotics in converting early lesions (nodules and plaques) from culture positive to culture negative. Lesions were excised either immediately or after treatment with rifampin orally at 10 mg/kg of body weight and streptomycin intramuscularly at 15 mg/kg of body weight daily for 2, 4, 8, or 12 weeks and examined by quantitative bacterial culture, PCR, and histopathology for M. ulcerans. Lesions were measured during treatment. Five lesions excised without antibiotic treatment and five lesions treated with antibiotics for 2 weeks were culture positive, whereas three lesions treated for 4 weeks, five treated for 8 weeks, and three treated for 12 weeks were culture negative. No lesions became enlarged during antibiotic treatment, and most became smaller. Treatment with rifampin and streptomycin for 4 weeks or more inhibited growth of M. ulcerans in human tissue, and it provides a basis for proceeding to a trial of antibiotic therapy as an alternative to surgery for early M. ulcerans disease.

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Summary A cross-sectional study led in Bamako analyzed the seroprevalence of hepatitis C virus (HCV) and its genotypes among 91 patients carrying chronic liver diseases at the stage of cirrhosis (53) or hepato cellular carcinoma (38) and, on comparative basis in 92 blood donors as control population. False serologic reactions were found with ELISA (3/91 either 3,3% of the liver diseases and 1/92 or 1,1% of the control). Positive tests by ELISA confirmed by a RIBA test were finally considered. Concerning all the liver diseases, the seroprevalence of HCV was 15,4% including 15,1% in cirrhosis, 21% in hepatocellular carcinoma patients versus 2,2% in blood donors. The HBs antigen was associated in 5,6% of the cases In the hepatite C population, genotype 2a/2c was definitely prevalent, about 85,7%. Thus the role of the HCV in genesis of cirrhosis and hepatocellular carcinoma in Mali, appears significant.

[Study of antigen HBs and antivirus antibodies of hepatitis C during hepatopathies in Mali]

A prospective study carried out in Bamako, Mali between July 1998 and January 1999 has assessed the seroprevalence of hepatitis C virus (HCV) in 91 carrier patients of chronic hepatopathy at a cirrhrosis stage (53) or of hepato-cellular carcinoma (38) and to compare with in 92 blood donors as a control population. Only seroprevalence confirmed by a complementary test has been taken into account (RIBA). HCV seroprevalence reached 25% including all hepatopathies, 24% in cirrhrosis and 26% in hepato-cellular carcinomae (HCC) versus 4% in blood donors. Antigen HBs of hepatitis B virus has been found in 55% of patients, versus 25% of the control cases (p = 0.0006). On the whole, the two markers have been notified a little more often in HCC than in cirrhosis and the combination of the two markers has been more frequent during cirrhosis as well. The role of HCV played in cirrhosis and HCC onset in Mali appears to be important.

[Ecology and transmission of Mycobacterium ulcerans]

Mycobacterium ulcerans is an environmental pathogen concerning mainly the tropical countries; it is the causative agent of Buruli ulcer, which has become the third most important mycobacterial disease. In spite of water-linked epidemiological studies to identify the sources of M. ulcerans, the reservoir and the mode of transmission of this organism remain elusive. To determine the ecology and the mode of transmission of M. ulcerans we have set up an experimental model. This experimental model demonstrated that water bugs were able to transmit M. ulcerans by bites. In insects, the bacilli were localized exclusively within salivary glands, where it could both multiply contrary to other mycobacteria species. In another experimental study, we report that the crude extracts from aquatic plants stimulate in vitro the growth of M. ulcerans as much as the biofilm formation by M. ulcerans has been observed on aquatic plants. Given that the water bugs are essentially carnivorous, it is difficult to imagine a direct contact in the contamination of aquatic bugs and plants. It seems very likely that an intermediate host exists. In an endemic area of Daloa in Côte d'Ivoire, our observations were confirmed.

[Epidemiological study of tuberculosis in the area of Angers, France, as studied by 3 PCR-based fingerprinting methods]

The new genotyping methods efficiently complement classical epidemiological investigation in order to attempt a global approach to TB control. In the present work, we have studied the genomic diversity of Mycobacterium tuberculosis isolated during the year 1998 within the district of Angers, France (260,000 inhabitants distributed in 29 districts), in order to identify recent transmission events and any related risk factors. The methods used included "spacer oligonucleotide typing" or spoligotyping, "variable number of DNA tandem repeats" or VNTR, and "double repetitive element PCR" or DRE-PCR. The resulting spoligotyping and VNTR results were also feeded to international databases and compared with >10,000 isolates for spoligotyping and 500 isolates for VNTR, representative of about 60 countries. The results obtained underlined that most of the TB cases in our setting probably reflected reactivation cases, as clustered cases indicative of potential events of recent transmission were rare. Furthermore, interrogation of international databases showed that most of the isolates from the Angers region belonged to major conserved families of TB isolates representative of Europe, with only rare cases of Asian origin, or those previously reported in specific epidemies reported from elsewhere.

[Mycobacterium ulcerans infection]

Mycobacterium ulcerans infection, or Buruli ulcer, is the third most common mycobacterial disease of the immunocompetent host in the tropical areas. M. ulcerans reservoir is aquatic. Infection occurs in children and young adults. The lesion begins with an indolent subcutaneous nodule, principally located on the limbs, that progressively changes into a deep indolent extensive ulcer. M. ulcerans produces a lipidic necrotic and immunosuppressive toxin, named mycolactone, that causes the clinical lesions. In endemic areas, clinical diagnosis is confirmed by microscopic examination. Spontaneous healing occurs after several months or years, causing retractile scars. Surgical excision and grafting is the treatment of choice. Antibiotic therapy is of limited value.

Surveillance of Mycobacterium tuberculosis drug resistance in France, 1995-1997. AZAY Mycobacteria Study Group

OBJECTIVE

To measure the rate of primary and secondary drug resistance of Mycobacterium tuberculosis on an ongoing basis.

DESIGN

Data on all culture-positive tuberculosis were collected prospectively from 1995 through 1997 from a microbiological laboratory network of 19 university hospitals throughout France, and submitted quarterly to the National Reference Centre for Surveillance of Mycobacterial Diseases.

RESULTS

A total of 2998 patients were included in the study. Among the 2333 (78%) previously untreated patients, 8.6% had isolates resistant to any drug, 4.8% to streptomycin (SM) alone, 1.2% to isoniazid (INH) alone, 1.8% to SM + INH, and 0.3% to INH + rifampicin (RMP) or multidrug resistance (MDR). Foreign birth was independently associated with a higher risk of primary resistance to any drug (odds ratio [OR] 1.5). Among the 268 (9%) previously treated patients, 20.9% had isolates resistant to any drug, 6.3% to SM alone, 3.4% to INH alone, 4.1% to SM + INH, and 3.7% to INH + RMP. Foreign birth (OR = 2.3), and human immunodeficiency virus positive status (OR = 4.4) were independently associated with a higher risk of secondary resistance to any drug.

CONCLUSION

During the last 30 years there has been no increase in resistance to any drug among previously untreated patients. As expected, secondary resistance was highly associated with foreign birth. MDR-TB remains a rare event in France.

[Severe pneumonia with a pneumococcal aspect during an ornithosis outbreak]

OBJECTIVES

To describe the clinical, radiological and biological features of Chlamydia psittaci pneumonia.

METHODS

A pneumonia outbreak occurred in a healthy middle-aged population working in a poultry slaughterhouse. Systematic serology (2 samples at 5 weeks intervals) provided the diagnosis of Chlamydia psittaci pneumonia in 6 patients. Patient files were analyzed retrospectively.

RESULTS

The clinical presentations in this series of pneumonia were particularly homogeneous with a pneumococcal profile in all 6 cases: sudden onset, temperature above 39 degrees C, lobar alveolar involvement, hypoxemia, hyperleukocytosis and liver dysfunction. One case of hallucinatory delirium was observed. The patients were given spiramycin (9 million units per day for 3 weeks) and all recovered rapidly with no complications.

CONCLUSION

The unusual virulence of the Chlamydia psittaci and very important inoculum were probably involved in this outbreak because of the severity of the pulmonary features and the short exposure of some patients to the bacteria. These cases suggest that the prevention of ornithosis in poultry slaughterhouses should be reinforced.

A blind study of the polymerase chain reaction for the detection of Mycobacterium tuberculosis DNA. Azay Mycobacteria Study Group

SETTING

Nine French laboratories routinely involved in mycobacterial work.

OBJECTIVE

To assess the detection of Mycobacterium tuberculosis in experimental samples by polymerase chain reaction (PCR) using the insertion sequence IS6110 as a target for deoxyribonucleic acid (DNA) amplification.

DESIGN

Nine laboratories participated in a blind study of the detection of M. tuberculosis by PCR in 20 coded samples containing either a definite number of M. tuberculosis complex (positive samples) or environmental mycobacteria (four samples) or no mycobacteria (five samples).

RESULTS

Five laboratories reported false-positive PCR results, with an average rate of 7%. All laboratories except one reported positive PCR results for samples containing 10(5) cfu/ml or more. M. tuberculosis DNA was detected in two thirds of samples containing 10(4) and 10(3) cfu/ml, and in one third of the samples containing 10(2) cfu/ml.

CONCLUSION

The results of the study suggest that PCR using IS6110 as a target for DNA amplication is neither very sensitive nor really specific for the detection of M. tuberculosis.

Diagnosis of tuberculosis by Amplicor Mycobacterium tuberculosis test: a multicenter study

The Amplicor Mycobacterium tuberculosis test is a new PCR assay for the direct detection of Mycobacterium tuberculosis from clinical samples. A multicenter study that included six laboratories was done to evaluate the Amplicor test in comparison with direct microscopy and culture (solid or radiometric media), and the culture method was used as the "gold standard." A total of 2,073 specimens, i.e., 1,749 respiratory specimens and 324 other specimens, were tested. A total of 184 cultures yielded M. tuberculosis. Of these 184 cultures, 77 (42%) were smear negative and 23 (12.5%) concerned extrapulmonary specimens. The sensitivity of the Amplicor test for all of the specimens and for extrapulmonary, smear-positive, and smear-negative specimens was 86, 83, 94.5, and 74%, respectively. The sensitivity of direct microscopy in comparison with that of culture was 58%. A total of 95% of patients with culture-proven tuberculosis were diagnosed by the Amplicor test, whereas direct microscopy detected mycobacteria in only 72% of these patients. The Amplicor test exhibited a high degree of specificity (98%). The assay was very rapid and easy to perform.

[Bacteriological diagnosis of tuberculosis: current hieratic classification of methods]

To assure the diagnosis of tuberculosis, one needs the observation, the isolation and the identification of the causative agent Mycobacterium tuberculosis. In this approach, the microscopic exam occurs as a fast but neither sensitive or specific test. The isolation on solid media is slow and needs more than three weeks before becoming positive. Nevertheless, it is a sensitive and specific one. The identification of the isolated strain and the study of sensitivity to antibiotic agents require an equal delay. Then, 2 months are necessary to achieve the analysis. The AIDS epidemic with the increase of opportunistic mycobacterial diseases, and the unexpected arrival of resistant Mycobacteria is creating as a difficult therapeutic problem. The cultivation in liquid media with the radiometric method (Bactec) shortens the time of culture by half. The genomic amplification assay has been hopeful because it allowed results in 2 days. However, some technical difficulties happen when the test is conducted and it is less sensitive than the isolation process. The hierarchical classification of the laboratory useful process to establish the diagnosis of tuberculosis disease remains the microscopic observation of the bacilli and their isolation. Today, the use of PCR alone does not assure the diagnosis of tuberculosis, however it may be used as a additional diagnostic test.

[Use of the Bactec TB 460 method for the bacteriological diagnosis of tuberculosis. Results of a multicenter study]

Isolation of Mycobacteria on Loewenstein-Jensen medium lasts many weeks. The use of Radiometric method (Bactec TB 460) reduces the delays. Results of 79,064 cultures are reported from a multicentric study associating 16 laboratories. The average was 4.8% of positivity and 2.51% of contamination. The comparison of the results with conventional method previously obtained shows that radiometric method is more sensitive and contaminations are less numerous. Concerning hemocultures the Bactec method is very usefull. Among 11,277 tests performed 907 were positive (8.04%). Mycobacterium avium was identified in 89% of the cases. Identification test utilizes Biochemical and NAP tests, but also more and more Nucleic probes. The antibiotic sensitivity is performed in five days. The mean delay of analysis is about 25 days, lessening by half the conventional method delays. Nevertheless, Bactec method has the following inconveniences: syringe inoculation, use of radiolabelled products, expensive cost.

French multicenter study involving eight test sites for radiometric determination of activities of 10 antimicrobial agents against Mycobacterium avium complex

The radiometric BACTEC 460-TB methodology has filled an increased need in the screening of a wide range of antimicrobial agents against Mycobacterium avium (MAC) isolates on a patient-to-patient basis. In this context, a multicenter study involving eight test sites across France was performed to determine the MICs of 10 antimicrobial agents for MAC organisms. The aim of the investigation was to compare the in vitro activities of D-cycloserine, ethambutol, ethionamide, rifampin, amikacin, streptomycin, ciprofloxacin, sparfloxacin, clofazimine, and clarithromycin against MAC isolates. All of the test sites received the same clinical isolates of MAC, and the MICs were determined by a common protocol. The overall interlaboratory reproducibility of the MICs within +/- 1 dilution of the modal MICs varied from 79.70 to 100% (mean, 95.2% +/- 2.1%), whereas overall agreement of the MICs among the test sites varied from a mean of 91% +/- 4.1% to a mean of 98 +/- 1.3%. We confirmed that the proposed methodology is easy, accurate, and sufficiently reproducible to be used routinely in a clinical laboratory. Despite variations in the MICs of the same drug among strains, no link between the origin of MAC isolates (from human immunodeficiency virus-positive or -negative patients) and their drug susceptibilities was established. On the basis of the MICs that inhibited 50 and 90% of isolates tested for the drugs used, clarithromycin, clofazimine, ethambutol, and streptomycin were the most uniformly active against MAC; this was followed by amikacin, rifampin, and sparfloxacin. On the other hand, ciprofloxacin, D-cycloserine, and ethionamide showed only marginal in vitro activities.

Specific interaction between Listeria monocytogenes and glycosylated albumins

We have previously shown that Listeria monocytogenes serovar 1/2b can bind strongly to bovine albumin (BA) glycosylated by glucosamine or fucosylamine with about 20 to 30 carbohydrate residues per albumin molecule. We now show that the binding is time-dependent, reversible, saturable and specific. The two glycosylated compounds inhibit each other competitively. Scatchard analysis showed that about 100 molecules of BA-glucosamide (heptameric configuration) and 14,300 molecules of BA-fucosylamide (monomeric configuration) bound per bacterial cell. The apparent dissociation constants for BA-glucosamide and BA-fucosylamide were found to be 3.9 x 10(-14) M and 3.5 x 10(-13) M, respectively.

Surface Listeria monocytogenes carbohydrate-binding components revealed by agglutination with neoglycoproteins

Carbohydrate-binding components were shown to be present at the surface of Listeria monocytogenes by means of a panel of neoglycoproteins using direct agglutination. These lectin-like components bind on neoglycoproteins bearing D-glucosamine, L-fucosylamine, or para-amino-phenyl-alpha-D-mannopyrannoside residues. The interactions were inhibited by the carbohydrate moieties specific to the neoglycoproteins. The protein nature of the lectin-like components of L. monocytogenes was ascertained by the loss of carbohydrate-binding capacity following protease treatment.

Rapid identification of Mycobacterium species

Identification of Mycobacterium species is currently a long and fastidious procedure. We have developed a rapid (5-h) standard method using the API-ZYM system and rapid nitratase, urease and catalase tests. Pigmentation and growth rate were noted (but were only necessary for complete identification of 6% of strains). The tests were assigned numerical values from which a profile number was derived. A total of 716 strains were studied: 434 belonging to the M. tuberculosis complex and 282 other mycobacteria including 21 from M. avium complex. All M. tuberculosis complex strains were differentiated from all other mycobacteria and M. bovis was clearly separated from M. tuberculosis. All M. avium complex strains were differentiated from other mycobacteria. Among mycobacteria other than tubercle bacilli, 97% of the strains studied were identified. The method has proven to be simple, rapid and standardizable. It is suggested that the use of a code list could permit identification of most mycobacteria.

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

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

[Epidemic of listeriosis in Western France (1975--1976)]

Cases of human listeriosis have recently increased in Western France (Maine-et-Loire and Mayenne); until 1974, there were only 15 documented cases yearly where as in 1975, there were 113 cases, and in 1976, 54 documented cases at the hospitals of Angers and Laval. Included amongst the clinical manifestations observed, were 126 cases of materno-fetal infections and 41 cases of either septicemia or meningo-encephalitis. The bacteriological study revealed a certain variability of biological characteristics examined, the overwhelming frequence of bacteria of the strain 4 b and the predictable sensitivity of this strain to antibiotics commonly employed in cases of listeriosis. The human cases were notably more frequent between January and June but their geographical distribution was not related to cases of either animal disease nor listeria that was isolated from corn silage. In this report, we propose an etio-pathological explanation for this epidemic.

[Epidemiology and prevention of tuberculous contamination in bacteriology laboratories. Results of a survey on 23 laboratories]

The authors have carried out a survey of 23 bacteriology laboratories to investigate tuberculous contaminations which took place from 1967 to 1972 in these laboratories. They have reviewed 20 accidents in 74 technicians who performs searches for tuberculous bacilli, and 29 accidents in the total amount of 379 technicians working in these 23 laboratories. A comparison of these results with the previous published investigations shows a rather high number of cases reported in our country. A review of the possible causes of contaminations leads to suspect bacterial aerosols and to put forward the use of laminar flow enclosures as a prevention. The authors have tested several vertical flow instruments built to different patterns. All three convenient enclosures have an architectural characteristic: their blowing ceiling overhangs the working plane. As these instruments have been under examination for three years in a laboratory where contaminations are very likely to happen, they have obtained interesting results.