Invasiveness of Listeria monocytogenes strains isolated from animals in Poland.

Animals are important reservoir of Listeria monocytogenes, a pathogen causing serious infections in both humans and livestock. However, data on invasiveness of L. monocytogenes strains of animal origin is very scarce. Ability of 18 L. monocytogenes strains of animal origin to invade HT-29 cells was investigated. Plaque forming assay was used to assess invasiveness and ability of the pathogen to spread in the cell line. Almost 40% of L. monocytogenes strains were weakly invasive. It was shown that strains from serogroup 4b exhibited the highest invasiveness, whereas serogroup 1/2b consisted of strains of invasiveness below 0.0001%. Analysis of translated inlA and inlB gene sequences revealed no premature stop codons. Lineage-specific mutations in low invasive strains were identified within inlA and inlB sequences. Our results demonstrate high incidence of low invasive animal L. monocytogenes strains, which may be at least partly explained by unique point mutations in the InlA and InlB.

Adhesion of Malassezia pachydermatis of different growth type to canine epithelial cells.

A total of 100 Malassezia pachydermatis strains recovered from skin and mucosal membranes of dogs were evaluated for their adhesive properties. Two types of growth, related to colony morphology on Sabouraud agar, were observed (type I and II). The mean number of fungal cells attaching to canine buccal epithelial cells was found to be 17. The number of adhered cells was greater (statistically significant at the level of p < 0.01) in strains belonging to the type I.

A 34-year retrospective study of equine viral abortion in Poland.

The purpose of the present review was a comparison of the abortions caused by EAV and EHV-1 viruses over the 34 years. A total of 452 tissues samples from aborted fetuses (347) or foals (105) stillborn or newborn that died within 72 hours were investigated. The material for the examinations came from different farms located throughout Poland. The tissue homogenates were examined by using virus isolation test in RK-13 and Vero cell lines and the cytopathic agent was confirmed as EHV-1 by the direct fluorescent antibody test or as EAV by the indirect fluorescent antibody test. The study indicated that EAV was isolated (104 cases, 23%) almost as equally often as EHV-1 (116 cases, 25.6%). Both, equid herpes virus-associated abortion and the abortion induced by EAV were characterized by cyclicity. The percentage of EAV and EHV-1 isolation alternately reduced and increased, but the increase of isolation of one virus was accompanied by the decrease of the other. The domination of one virus over the other occurred in cycles of a few years.

Influence of immunisation with enteropathogenic and non-enteropathogenic Escherichia coli on the occurrence of loop dilation in rabbits.

The protective effects of high levels of O115 antibodies and K88 antibodies in the sera of hyperimmunized rabbits on the intestinal loop dilation elicited by live cultures of Escherichia coli O115: K88:H39 and its enterotoxins were examined. K88 antibodies did not prevent fluid accumulation when live E coli O115:K88:H39 or its enterotoxins were injected into ligated loops in rabbits actively immunised with K12:K88 or when K88 antiserum was mixed directly with the challenge shortly before injection into the loops. In two of six rabbits immunised with heat-killed O115 E coli the live strain failed to elicit a fluid response and in two others the response was reduced. In all cases the O115 antiserum inhibited the fluid response evoked by the live, homologous bacteria, but not by enterotoxin preparations, when the serum was mixed directly with the challenge before injection.

[Level of macrophages and lymphocytes reacting with nitro-tetrazole blue (NBT) in mice infected with Yersinia enterocolitica]. / Poziom makrofagów i limfocytów reagujacych z blekitem nitrotetrazoliowym (NBT) u myszy zakazonych Yersinia enterocolitica.

The study was aimed at investigation of reducing ability of nitrotetrazol blue (NBT) by peritoneal fluid macrophages and spleen and mesenteric lymph node during experimental yersiniosis. Investigations were carried on BALB/c mice infected perorally by the dose of 10(6) of live, virulent cells of Y. enterocolitica. It was found that clear increase of metabolic activity in macrophages occurred between 3 and 12 day after infection, in spleen lymphocytes between 6 and 9 day, whereas it was noted in mesenteric lymph node between 6 and 15 day after infection. Maximal stimulation of macrophages was observed at the 6th day of lymphocytes on 9th day after infection. These results suggest that macrophages are the first cells which react to infection with Y. enterocolitica. Activity of spleen and mesenteric lymph node lymphocytes during first days of infection appeared relatively small.

[Serological studies of human Yersinia enterocolitica infections]. / Badania serologiczne u ludzi w kierunku zakazen paleczkami Yersinia enterocolitica.

Sera of 1283 patients from hospitals and medical centers of Wroclaw were examined for Y. enterocolitica antibodies. In 29% examined sera anti-Y.enterocolitica antibodies of titer 1:40 and greater were noted. The agglutinins against serotype IA(3) were in 82.5%, against V(9) in 8.6% and against both serotypes mentioned above in 8.8%. In the group of sera positive for serotype IA 70.2% of sera gave positive reaction using antigen made from the humans strains and 9.1% using antigen prepared from swine Y.enterocolitica isolate. Patients with the positive titer of agglutinins against Y.enterocolitica in their sera mainly shoved the symptoms of gastroenterocolitis (54.8%) and arthritis (14.5%). The highest percentage reactions was in children aged 7-14 years (47.3%) whereas in adults it was lover (28.8%).

Typing of Yersinia Enterocolitica Isolates by ITS profiling, REP- and ERIC-PCR.

Thirty-five Yersinia enterocolitica strains isolated from humans, pigs and foxes were analysed by genotyping including intergenic transcribed sequence (ITS) profiling, REP- and ERIC-PCR. ERIC-PCR revealed the presence of seven different genotypes. Amplification of the 16S-23S rDNA spacer region by ITS profiling gave similar results with nine different genotypes. REP-PCR was found to be more discriminatory for typing of Y. enterocolitica than ERIC-PCR and ITS profiling. Fifteen different DNA patterns were obtained by this technique. Based on data obtained by three methods it was found that: (i) Y. enterocolitica strains belonging to the same serotype can represent different genotypes and vice versa; (ii) isolates recovered from humans, pigs and foxes exhibit limited heterogeneity and, independent of the origin, one or two prevailing genotypes were always observed; and (iii) many human Y. enterocolitica isolates shared common genotypes with porcine isolates.