Virulence factors (aerobactin and mucoid phenotype) in Klebsiella pneumoniae and Escherichia coli blood culture isolates.

We examined the presence of two virulence factors in 241 blood isolates of Klebsiella pneumoniae from patients hospitalized during 1989 and 1990 in 7 French hospitals, and 125 blood isolates of Escherichia coli from one hospital. Aerobactin was scored phenotypically and genotypically with an intragenic DNA probe of 2 kb. The mucoid phenotype was assessed by culture on trypticase soy agar and by genotypic analysis (intragenic DNA probe of 235 bp). Only 6% K. pneumoniae isolates were aerobactin-positive with no significant variation according to geographical location while 20% of K. pneumoniae isolates displayed the mucoid phenotype, with a significant variation according to hospital. Aerobactin was always associated with the mucoid phenotype. The frequency of aerobactin production but not mucoid phenotype (14%) was higher among E. coli isolates (48%). They harbored two types of large plasmids. Intraperitoneal injection into mice of 10(3) cfu of K. pneumoniae producing both virulence factors demonstrated that capsular serotype K2 was the more virulent K23 and K28.

[Use of the Bactec TB 460 method for the bacteriological diagnosis of tuberculosis. Results of a multicenter study]. / Utilisation de la méthode Bactec TB460 pour le diagnostic bactériologique de la tuberculose. Résultats d'une étude multicentrique.

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.

Cytotoxicity of Pseudomonas aeruginosa internal lectin PA-I to respiratory epithelial cells in primary culture.

Pseudomonas aeruginosa is the most important bacterial pathogen associated with chronic airway infection, especially in cystic fibrosis. We addressed the question of whether the galactophilic internal lectin of P. aeruginosa (PA-I) could represent a virulence factor for the respiratory epithelium. PA-I lectin was localized in all the bacteria of P. aeruginosa ATCC 33347 as determined by immunofluorescence staining. We investigated the dose-dependent effect of P. aeruginosa PA-I lectin on the growth, the ciliary beating frequency, and the morphology of human respiratory cells in primary culture of nasal polyps collected from non-cystic fibrosis patients. PA-I lectin significantly (P < 0.01) inhibited the growth of respiratory cells at a concentration of > or = 10 micrograms/ml. The percentage of active ciliated cell surface of the cultures decreased significantly (P < 0.05) at a PA-I lectin concentration of 50 micrograms/ml. Exposed to a low concentration of PA-I lectin (10 micrograms/ml), respiratory epithelial cells showed intracytoplasmic vacuoles when examined by light and transmission electron microscopy. At a higher concentration of PA-I lectin (100 micrograms/ml), major cell damage and severe epithelial shedding occurred. These results demonstrate that the P. aeruginosa internal PA-I lectin has a dose-dependent cytotoxic effect on respiratory epithelial cells in vitro. The P. aeruginosa PA-I lectin may represent a virulence factor by contributing to the respiratory epithelial damage during P. aeruginosa respiratory infections.

[First isolation of Borrelia afzelii in France (Marne) from Ixodes ricinus]. / Premier isolement en France (Marne) de Borrelia afzelii à partir d'Ixodes ricinus.

A strain of Borrelia has been isolated from Ixodes ricinus in France (Marne). The DNA analysis by PCR showed that it is identical to B. afzelii.

Spontaneous abortions during the second trimester of gestation.

To determine the factors causing spontaneous abortions, 422 consecutive second-trimester abortions and the corresponding clinical data were studied prospectively. All of the fetuses and placentas were referred to a single pathologist and microbiological cultures were carried out in 205 of these cases. One hundred twenty-one medically included abortions were used as controls for the interpretation of the investigations relating to infection. According to the degree of maceration, two groups could be isolated and seemed to represent different diseases and mechanisms of spontaneous abortions. In the largest group (78.6%) without long intrauterine retention, one explanation could be given for 85% of these cases. Ascending infections occurred through unruptured membranes, whether or not they were associated with obstetric complications. The second group (21.4%) included severely macerated fetuses where a cause of death could only be determined in 44% of the cases that had a predominance of fetal abnormalities and maternal factors.

Fetal listeriosis during the second trimester of gestation.

Listeriosis is common and is implicated in about 3% of second-term abortions examined in our laboratory. Maternal fever was followed rapidly in all instances by the expulsion of a nonmacerated fetus. Chorioamnionitis was always present and was associated with placental microabscesses. Leukocytic infiltrates were frequent in fetal tissues, being present in adrenal, lung, and skin. Listeria monocytogenes was isolated from 8 of the 205 abortions that had microbiological cultures (3.9%). The clinical features and morphological lesions were so characteristic that the diagnosis of listeriosis could be made in 5 of the 217 fixed abortuses received during the same period, but without culture. In contrast to the third trimester of pregnancy, there were no inflammatory lesions in the central nervous system in our small series.

Incidence of two virulence factors (aerobactin and mucoid phenotype) among 190 clinical isolates of Klebsiella pneumoniae producing extended-spectrum beta-lactamase.

Because outbreaks of multiple-resistant Klebsiella pneumoniae isolates producing extended-spectrum beta-lactamases were recently observed in French hospitals, the presence of virulence factors was examined for (i) phenotype by bioassay for aerobactin production and by culture for the mucoid phenotype, and (ii) genotype using intragenic probes of respectively 2-kb BglII and 235-bp BamHI-BglII fragments and dot-blotting among 190 unreplicated K. pneumoniae clinical isolates issued from 25 French hospitals and producing different types of extended-spectrum beta-lactamases (TEM-related enzymes: TEM-3, TEM-4, CAZ-1, CAZ-2, TEM-8, or SHV-related enzymes: SHV-2, SHV-3, SHV-4). Only 3.7% and 7% of K. pneumoniae isolates produced aerobactin and mucoid phenotypes respectively, unrelated to type of beta-lactamase. Only 2% had both factors. No discordance was reported according to the detection method tested. The low prevalence of such virulence factors seems to indicate they were not involved in dissemination of nosocomial K. pneumoniae isolates producing an extended-spectrum beta-lactamase.

[Animal bites. Epidemiology and infection risks]. / Morsures d'animaux. Epidémiologie et risques infectieux.

A review of 5,116 cases of animal bites (587 of which were studied prospectively) has shed some light on their epidemiological aspects and on the risk of infection they carry. It has also led to a more objective assessment of the real effect of the therapeutic and prophylactic measures usually applied in such cases. The most frequent wounds are those of the hands and face, the former rising an infectious problem, the latter a predominantly cosmetic problem. The overall risk of infection is 30 per cent, but it is increased, notably as regards pasteurellosis, in the case of cat bite. Precise and simple rules concerning the prevention of this risk cannot easily be given, but it seems that the systematic antibiotic treatment initially prescribed has not clearly proved effective. Similarly, early sutures do not significantly increase the risk of infection.

[Teicoplanin and Gram-positive coccus infections. Results of a multicenter study on 66 cases]. / Téicoplanine et infections à Cocci à Gram positif. Résultats d'une étude multicentrique sur soixante-six observations.

Sixty-six cases of Gram positive infections were treated with teicoplanin in an open multicenter study, comprising 7 centers in Eastern France. There were 38 male patients and 28 females. Teicoplanin was given at a dose of 400 mg daily for a mean duration of 18.4 days. The most common infections were due to Staphylococcus aureus, found in 43 out of 56 documented cases. 69 (89.9%) of the 78 Gram + strains isolated had an MIC for teicoplanin of less than or equal to 2 mg/l. There were 44 serious infections (30 septicemia, 10 endocarditis, 1 joint and bone infection, 2 mediastinitis, 1 toxic shock syndrome) and 22 less serious infections (4 urinary infections, 14 skin and soft tissue infections, 3 lower respiratory infections, 1 hepatic abscess). In 42 cases concurrent medication was given: beta-lactamase in 11 cases, rifampicin in 10 cases, aminoglycosides in 22, phosphomycin in 3, pefloxacin in 5. The clinical cure and improvement rate was 90.10%. Adverse events were reported in 11 patients, and in only 3 cases was the therapy stopped. All were reversible on stopping therapy. Teicoplanin was found to be well tolerated and effective in the treatment of Gram positive infections in this study.

[15 new serotypes of Salmonella of subgenus I isolated in Africa]. / Quinze nouveaux sérotypes de Salmonella du sous-genre I isolées en Afrique.

Filteen new serotypes of Salmonella belonging to the sub-genus I have been isolated in Africa. Isolated in Ivory Coast: S. dabou (8,20:Z4,Z23,l,W), S. elokate (9,12:c:1,7), S. assinie (3,10:1,w:Z5), S. anna (13,23:Z35:e,n,Z16), S. mpouto (16:m,t:-), S. banco (28:r:1,7), S. abidjan (38:b:l,w); in Senegal: S. bignona (17:b:e,n,Z15), S. lode (17:r:1,2), S. derkle (52,e,h:1,7); in Tchad: S. moussoro (1,6,14,25:i:e,n,Z15), S. drogana (1,4,12,27:r,i:e,n,Z15); in Algeria: S. hydra (21:c:1,6); in Haute-Volta S. farakan (28:Z10:1,5); in Republique Centrafricaine: S. babili (28:Z35:1,7).