Prevalence of virulence markers of enteric Campylobacter in France and Tunisia.

Forty-nine strains of Campylobacter jejuni and C. coli were isolated from the stools of 49 patients clinically documented for diarrhoea and fever, and living either in the Paris metropolitan area (30) or in the Tunis area (19). The strains were identified biotyped, serotyped and studied for association with HeLa cells and the ability to elongate Chinese ovary cells (CHO). The C. jejuni biotype I was more frequent among Tunisian strains and the C. jejuni biotype II was more frequent among French strains. Twenty-four strains associated with HeLa cells (A phenotype) and 21 elongated CHO (E phenotype). These 2 phenotypes were independently distributed in individual strains and were not related to the biotypes. We defined 4 pathovars according to the presence (A and E) or absence (a and e) of these 2 markers. The prevalence of the 4 pathovars was not correlated with the origin of the strain. The lack of a virulence marker (phenotype a/e) was correlated with the lack of clinical signs of diarrhoea and fever (p = 4 x 10(-5)). We concluded that at least 1 of the 2 in vitro virulence markers is related to the pathogenicity of the strains in the humans.

Association with HeLa cells of Campylobacter jejuni and Campylobacter coli isolated from human feces.

We developed a rapid in vitro test for determining the association of Campylobacter jejuni and C. coli with HeLa cells. Association was expressed as a weighted mean of the number of bacteria associated with one cell in an association index (AI). The reproducibility of the AI was checked by repeating the test six times, using four strains chosen at random. Means and standard deviations of the means were 7.3 +/- 1.2, 6.8 +/- 0.9, 1.8 +/- 1.2, and 0.1 +/- 0.2. The experimental conditions for which the results are reliable have been standardized. Among 42 strains from human feces, two groups appeared: for 22 nonassociative strains (52%), AI values ranged from 0.0 to 2.1 (mean +/- SD, 0.5 +/- 0.6); for 20 associative strains (48%), AI values ranged from 3.5 to 8.3 (mean +/- SD, 6.2 +/- 1.4). Of these 42 strains, 17 were clinically documented. Diarrhea occurred more frequently in patients infected with associative strains than in those infected with noninvasive strains (7/7 versus 3/10, P = 0.01). Fever also occurred more frequently in patients infected with associative strains (6/7 versus 2/10, P = 0.03). Transmission electron microscopy and viable counts made after killing of extracellular bacteria by gentamicin support the fact that associated Campylobacter spp. are adherent to the cell membrane and are internalized into cytoplasmic vacuoles. The described test seems to be a convenient and rapid method for estimating the pathogenicity of a given strain.

Risk and consequence of infection at the site of microsurgical repair: an experimental model.

The consequences of postoperative infection at the site of microsurgical repair were studied. The experiment used 60 Wistar rats which were divided into 3 groups of 20 each. The femoral artery, vein, and nerve were transected unilaterally and repaired using microsurgical techniques. Staphylococcus aureus was then inoculated into the wound of group 1. Beta-hemolytic Streptococcus was inoculated into the wound of group 2. Group 3 rats served as controls. Clinical, anatomical, bacteriological and histopathological examinations were performed on postoperative days 8 and 30. Wounds in which S. aureus was inoculated demonstrated a significant tendency toward vascular thrombosis with extensive tissue destruction. In the majority of these cases, the necrosis caused by the primary infection engendered an associated, opportunistic infection. Streptococcal inoculations in group 2 demonstrated less severe changes than in group 1. These changes were characterized by injury of the vascular structures themselves with a significant tendency for thickening of the arterial wall, perivascular inflammation, and hematoma formation at the site of the repair. This model allows demonstration of the enzymatic and toxic consequences of bacterial infection in a postoperative site characterized by cellular destruction and interstitial edema surrounding foreign bodies represented by sutures.

[Modification of intestinal colonization and translocation of Campylobacter jejuni by erythromycin and an extract of Lactobacillus acidophilus in axenic mice]. / Modification par l'érythromycine et un extrait de Lactobacillus acidophilus de la colonisation de l'intestin et de la translocation de Campylobacter jejuni chez la souris axénique.

Erythromycin (15 mg) or lyophylized heat-killed Lactobacillus acidophilus (80 mg) were administered per os daily in germ-free mice infected at day O with 10(7)-10(8) Campylobacter jejuni per os. Bacterial colonization of intestine and bacterial translocation of C. jejuni toward mesenteric lymph nodes, blood and liver were then studied for 5 days. The results were compared with those from an infected untreated control group. Compared to the control group, the numbers of free and mucosa-associated bacteria decreased at day 5 in the erythromycin-treated group and the number of mucosa-associated bacteria was reduced from day 1 to day 5 in the Lactobacillus-treated group. Both treatments reduced the frequency of bacterial translocation toward mesenteric lymph nodes from day 1 to day 5. We concluded that both erythromycin and heat-killed L. acidophilus are effective in treating Campylobacter infection in mice, though probably through different mechanisms.

[Activity of amoxicillin and ampicillin against infection with Salmonella typhimurium in mice ]. / Comparaison de l'ampicilline et de l'amoxicilline comme traitement de l'infection expérimentale de la souris par Salmonella typhimurium.

Experimental mouse intraperitoneal or intragastric infection due to Salmonella typhimurium C5 was treated with subcutaneous amoxicillin or ampicillin. The minimum inhibitory concentrations (MIC) and the minimum bactericidal concentrations (MBC) of the two penicillins were similar. Amoxicillin was significantly more effective than ampicillin in protecting the animals from the lethal effects of the infection. The enumeration of bacteria from spleen and Peyer's patches of the small intestine showed that amoxicillin killed S. typhimurium faster than ampicillin.