ABSTRACT
In several hospitals in Beirut, Lebanon, 77 isolates of Escherichia coli were successfully derived from the stools of patients with diarrhoeal diseases, by culture on MacConkey or MacConkey-sorbitol agar. When the isolates were screened, using a multiplex PCR, 14 (from 14 different patients) were each found positive for one of the various genes defining the enterotoxigenic (five), enteroinvasive (four), enteroaggregative (three) or enteropathogenic (two) groups. Genotyping of these 14 diarrhoeagenic isolates, by pulsed-field gel electrophoresis, indicated that all were genomically distinct with the exception of two of the enteroaggregative isolates (which were of the same genotype). The E. coli apparently involved in diarrhoeal disease in Beirut therefore belong to at least four different diarrhoeagenic groups and show strain variation within each group. Diarrhoea in the absence of diarrhoeagenic E. coli may be the result of infection with bacteria other than E. coli or viral or parasitic enteropathogens.
Subject(s)
Diarrhea/microbiology , Escherichia coli/classification , Feces/microbiology , Adolescent , Adult , Bacterial Typing Techniques/methods , Child , DNA, Bacterial/genetics , Electrophoresis, Gel, Pulsed-Field/methods , Escherichia coli/genetics , Escherichia coli/isolation & purification , Genotype , Humans , Middle Aged , Polymerase Chain Reaction/methodsABSTRACT
Nuclear DNA contents (4C) were estimated by Feulgen microdensitometry in 27 species of slipper orchids. These data and recent information concerning the molecular systematics of Cypripedioideae allow an interesting re-evaluation of karyotype and genome size variation among slipper orchids in a phylogenetic context. DNA amounts differed 5.7-fold, from 24.4 pg in Phragmipedium longifolium to 138.1 pg in Paphiopedilum wardii. The most derived clades of the conduplicate-leaved slipper orchids have undergone a radical process of genome fragmentation that is most parsimoniously explained by Robertsonian changes involving centric fission. This process seems to have occurred independently of genome size variation. However, it may reflect environmental or selective pressures favoring higher numbers of linkage groups in the karyotype.
ABSTRACT
Hemodialysis patients are at high risk of developing HCV infection. Reports from various countries have shown a prevalence of 12-29% among this group. The present study aimed at assessing the utility of HCV antibodies and HCV-RNA detection in the diagnosis of HCV in Lebanese hemodialysis patients. One hundred and eight hemodialysis patients from various hospitals in Lebanon were assayed for the presence of anti-HCV antibodies by ELISA and LIA, and for the presence of HCV-RNA by RT-PCR of the 5' Non-coding region (5' NCR). Specificity of the amplicons was confirmed by Southern hybridization. Seventeen out of 108 patients were reactive in ELISA and positive in the Line Immunoassay (LIA). Eleven out of the 17 were positive by RT-PCR. Three out of 29 patients nonreactive in ELISA were positive by RT-PCR. Our results indicate that hemodialysis patients in this study may be grouped into 4 categories. These include (1) patients with viremia and no immune response, (2) patients with no viremia and with an immune response, (3) patients with both viremia and immune response and (4) patients with no viremia and no immune response. The first 3 categories may reflect the different phases of HCV infection and imply that detection of both anti-HCV antibodies and HCV-RNA are needed for the establishment of adequate diagnosis. In addition, data collected from patients implicated in this study show that infection by HCV may be dialysis machine-related, rather than transfusion-related. However, cross-contamination unrelated to machines may also occurs.
Subject(s)
Hepacivirus/genetics , Hepatitis C Antibodies/analysis , RNA, Viral/analysis , Renal Dialysis , Blotting, Southern , Cross Infection/virology , Enzyme-Linked Immunosorbent Assay , Hepacivirus/immunology , Hepatitis C/diagnosis , Hepatitis C/etiology , Hepatitis C/immunology , Humans , Immunoassay , Lebanon , Nucleic Acid Hybridization , Polymerase Chain Reaction , Prevalence , RNA, Viral/genetics , Renal Dialysis/adverse effects , Renal Dialysis/instrumentation , Risk Factors , Time Factors , Transcription, Genetic , Transfusion Reaction , Viremia/diagnosisABSTRACT
We have genotyped the 5' noncoding region of hepatitis C virus in Lebanese hemodialysis patients by reverse transcription-PCR and restriction fragment length polymorphism analysis. Of 50 patients, 15 had the expected 268-bp amplicon by reverse transcription-PCR. Specificity of the amplicons was confirmed by Southern hybridization. Restriction analysis of the amplicons showed the pattern for genotype 4 (common in the Middle East).
