Phylogeny of the genera Entamoeba and Endolimax as deduced from small-subunit ribosomal RNA sequences. (1/5)

We sequenced small-subunit ribosomal RNA genes (16S-like rDNAs) of 10 species belonging to the genera Entamoeba and Endolimax. This study was undertaken to (1) resolve the relationships among the major lineages of Entamoeba previously identified by riboprinting; (2) examine the validity of grouping the genera Entamoeba and Endolimax in the same family, the Entamoebidae; and (3) examine how different models of nucleotide evolution influence the position of Entamoeba in eukaryotic phylogenetic reconstructions. The results obtained with distance, parsimony, and maximum-likelihood analyses support monophyly of the genus Entamoeba and are largely in accord with riboprinting results. Species of Entamoeba producing cysts with the same number of nuclei from monophyletic groups. The most basal Entamoeba species are those that produce cysts with eight nuclei, while the group producing four-nucleated cysts is most derived. Most phylogenetic reconstructions support monophyly of the Entamoebidae. In maximum-likelihood and parsimony analyses, Endolimax is a sister taxon to Entamoeba, while in some distance analyses, it represents a separate lineage. The secondary loss of mitochondria and other organelles from these genera is confirmed by their relatively late divergence in eukaryotic 16S-like rDNA phylogenies. Finally, we show that the positions of some (fast-evolving) eukaryotic lineages are uncertain in trees constructed with models that make corrections for among-site rate variation.  (+info)

Cockroaches (Blattella germanica) as carriers of microorganisms of medical importance in hospitals. (2/5)

A study was conducted to isolate and identify microorganisms of medical importance from cockroaches (Blattella germanica) and to ascertain their vector potential in the epidemiology of nosocomial infections. Bacteria, fungi and parasites of medical importance were isolated and identified. Important bacterial pathogens responsible for wound infections, were further studies by antibiograms. One hundred and fifty-eight out of 159 (99.4%) cockroaches collected from hospital (test) and 113 out of 120 (94.2%) cockroaches collected from residential areas (control) were carrying medically important microorganisms (P less than 0.05). significantly higher (P less than 0.001) number of test cockroaches were carrying a higher bacterial load (1 x 10(4) and 1 x 10(5] as compared to control cockroaches. Multiple drug-resistant bacterial were isolated from test cockroaches. The diversity of drug-resistant bacterial species isolated from test cockroaches suggests their involvement in the transmission of drug-resistant bacteria. Various fungi and parasitic cysts of medical importance were also isolated from the test and control cockroaches, but the carriage rates were low. The findings suggest that cockroaches, in hospitals, can act as potential vectors of medically important bacteria/parasites/fungi.  (+info)

Prevalence of enteric parasites in homosexual patients attending an outpatient clinic. (3/5)

A total of 372 pooled stool specimens from 274 homosexual men with diarrhea were submitted for parasitologic examination over a 2.5-year period. Each two-vial pooled specimen set contained portions of stool from 3 consecutive days in Formalin and polyvinyl alcohol. Of the 274 patients, 133 (48.5%) harbored one or more intestinal protozoa, with 161 (43.3%) of the 372 specimens submitted being positive for one or more organisms. The parasites identified included Entamoeba histolytica (71 patients), Giardia lamblia (22 patients), Endolimax nana (106 patients), Entamoeba coli (39 patients), Entamoeba hartmanni (25 patients), Dientamoeba fragilis (3 patients), Iodamoeba butschlii (2 patients), and Chilomastix mesnili (2 patients). Cryptosporidium sp. (2 patients) and Isospora belli (1 patient) were also detected. Results of this study support the experience of other workers regarding high rates of infection with intestinal parasites in the homosexual population and also indicate that symptomatic individuals belonging to this acquired immunodeficiency syndrome risk group be screened for both common and uncommon intestinal pathogens.  (+info)

Carriage of intestinal protozoal cysts in homosexuals. (4/5)

A total of 83 male homosexuals were studied to ascertain the carriage of intestinal protozoal cysts. The homosexual group had a significantly (p less than 0.0005) higher prevalence than a control group. One or more types of protozoa were found in 33 homosexuals. The carriage of intestinal protozoal cysts was associated with particular sexual practices and promiscuity, but not with symptomatic bowel disorders. The possible implications of the carriage of these cysts are discussed.  (+info)

Development of monoclonal antibodies specifically recognizing the cyst stage of Entamoeba histolytica. (5/5)

Protozoan cysts were isolated according to a two-step sucrose gradient procedure. Pure cysts of Entamoeba histolytica, in fixed and native states, were injected into BALB/c mice intraperitoneally for immunization. The spleens of these animals were used for fusion with AG8 mouse myeloma cells. Hybridomas were obtained and tested for the recognition of E. histolytica, E. dispar, E. coli, E. hartmanni, Endolimax nana, Jodamoeba biitschlii, and Giardia lamblia. Three monoclonal antibodies were identified that reacted only with cysts and trophozoites of E. histolytica. These can be used for differentiation and identification of E. histolytica in feces.  (+info)