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- Molecular Diagnosis and Vaccines
- OA African Journal Archive
- Volume 2, Issue 1, 2004
Molecular Diagnosis and Vaccines - Volume 2, Issue 1, 2004
Volume 2, Issue 1, 2004
Source: Molecular Diagnosis and Vaccines 2, pp 1 –13 (2004)More Less
Blood-born viral infections are common in Egypt especially hepatitis C virus (HCV) and hepatitis B virus (HBV). Abbott investigators in 1995 discovered two new Flavi-like viruses (GBV-A and GBV-B) derived from tamarins inoculated with GB agents. A third genus was subsequently isolated and given the name GBV-C. We investigated the clinical and epidemiological factors attributed to HCV/GBV-C co-infection as well as HCV genotypes in 246 anti-HCV positive Egyptian high-risk subjects: chronic liver disease (CLD), blood donors, hemodialysis patients, and family contacts of index patients. Detection of HCV antibodies was carried out by EIA-2, HCV RNA by nested RT-PCR. HCV genotypes by RFLP, HCV viral quantitation by bDNA-2, and GBV-C RNA by LCx assay. HCV RNA was detected in 53% of the overall population, 56% of CLD, 60% of blood donors, 54% hemodialysis patients, and 0% family contacts. HCV-viremia was unrelated to all risk factors including schistosomiasis, duration of disease or pathology of schistosomiasis. HCV type-4 was found in 74.5% of patients, type-1b in 15.6%, and type-1a in 5.7%. An overall GBV-C RNA prevalence of 12.8% was found [CLD (11.2%), blood donors (6.7%), hemodialysis (11.1%), family contacts (0%)]. However, GBV-C viremia as well as HCV/GBV-C co infection was associated with a greater frequency of schistosomal infection (p=0.005, and p=0.000 respectively). In conclusion, in Egypt (i) GBV-C infection is high among Egyptian high risk patients, (ii) GBV-C infection and GBV-C/HCV co-infection are associated with schistosomiasis, (iv) HCV genotype 4 is the most common genotype, with a minority of 1a and 1b, (v) HCV but not GBV-C viremia is associated with elevated liver enzymes (vi) both HCV and GBV-C infections are not associated with any of the known parentral risk factors, raising the possibility of non-parentral or occult routs of transmission.
VP4 and VP7 genotyping of human rotavirus: relationship between genetic variation and severity of infantile gastroenteritisSource: Molecular Diagnosis and Vaccines 2, pp 15 –26 (2004)More Less
Specific and sensitive tests for detection and typing of group A rotavirus strains are needed for a more comprehensive knowledge of the epidemiology of rotaviral infection. In this study 30 stool specimens from infants with acute gastroenteritis with age ranging from 2-12 months were examined. Group A rotavirus was unequivocally demonstrated in 60% of samples by latex agglutination test, in 40% by enzyme linked immunosorbant assay (ELISA) and in 36.3% by polymerase chain reaction (PCR). The infection was common among males and with artificial feeding than breast feeding. G and P typing of rotavirus was carried out by RT-PCR by amplification of VP7 and VP4 genes. Results showed the presence of VP4 in 16.7% of cases, VP7 in 13.3% and mixed VP4 and VP7 in 6.7% of cases. VP7 genotype was associated with the most severe symptoms followed by mixed VP4 and VP7 then VP4 gene. Detection of faecal rotavirus specific IgM and IgA antibodies in stool samples demonstrated that IgA antibodies are present in 33.3% of positive cases and in 11.1% of negative cases where virus shedding was no longer observed, while IgM was detected in 25% of positive cases and in 5.6% of negative cases. When RT-PCR was considered as the gold standard method for the detection of rotavirus in stool samples, ELISA and Latex assays sensitivity was found to be 90.4% and 72.3%, specificity 89.5% and 47.4% and accuracy 90% and 56.7% respectively. It is concluded that RT-PCR is a convenient method for genotyping of rotavirus strains. VP7 genotype correlates with the severity of infantile gastroenteritis. ELISA technique is a rapid, sensitive and inexpensive procedure for the direct detection of rotavirus antigen in clinical pecimens. However, detection of IgM and IgA antibodies is a useful supplement for diagnosis recent infection.
Source: Molecular Diagnosis and Vaccines 2, pp 27 –36 (2004)More Less
Acquired cholesteatoma is a complication of chronic otitis media that is usually associated with an intense local inflammatory reaction. Chlamydia pneumoniae is an intracellular pathogen associated with several chronic inflammatory disorders including asthma, atherosclerosis, and Alzheimer disease. To investigate the presence of C. pneumoniae in middle ear cholesteatoma, tissue samples were collected from 30 patients undergoing middle ear surgery and processed by polymerase chain reaction for detection of C. pneumoniae, in relation to other two common middle ear pathogens, Mycoplasma pneumoniae and Haemophilus influenzae. C. pneumoniae was detected in (60%) of cholesteatoma patients . Two specimens contained H. influenzae (6.7%) and three contained Mycoplasma (10%) of which two were M. pneumoniae. A significant difference was noted (p<0.001) when the frequency of C. pneumoniae was compared with other organisms. However, on comparing the frequenct C. pneumoniae with age, gender, and smoking habits, no significant difference was observed (p>0.05). On the other hand the recurrence of cholesteatoma among C. pneumoniae positive samples was 23.3% as compared to 6.7% in C.pneumoniae negative samples (p<0.05). The high frequency of C. pneumoniae in cholesteatoma tissues may indicate an important role of this pathogen in the pathogenesis of cholesteatoma. We hypothesize that the immunological background of subjects prone to cholesteatoma formation and to easy recurrence can facilitate middle ear colonization by C. pneumoniae.
Source: Molecular Diagnosis and Vaccines 2, pp 37 –44 (2004)More Less
Vascular endothelial growth factor (VEGR) and its receptors are focus of interest because of their role in several biological processes that involve angiogenesis in non malignant and malignant states. This work aimed to valuate the serum level of vascular endothelial growth factor in children with different haematological malignancies and to correlate its level with the clinical manifestations and laboratory data of the disease. The study was carried out on 36 children with newly diagnosed hematological malignancies. They were divided into 3 groups. Group 1 included 20 patients with acute leukemia; 14 of them had acute lymphoblastic leukemia (ALL) and 6 had acute myeloblastic leukemia (AML). Group 2 included 10 patients with non-Hodgkins lymphoma (NHD), while group 3 included 6 patients with Hodgkin's lymphoma (HD). In addition, ten apparently healthy age and sex matched children as control group (group 4) were included. All groups were subjected to a complete history taking, full clinical examination and complete diagnostic work up to diagnose acute leukemia and lymphoma. Serum VEGF level was detected by enzyme linked immunosorbent assay (ELISA) at diagnosis. Investigations were repeated in the leukemic patients after induction of remission. The level of serum VEGF was significantly higher in all patients than control. However, no significant difference between the levels of serumVEGF in ALL and AML patients or in NHL and HD patients was detected. A significant (p<0.001) decrease in serum level VEGF was found in leukemic patients after induction of remission as compared with the newly diagnosed leukemic patients. SerumVEGF level showed significant correlation with the WBCs count in ALL and NHL groups, and with the platelet count in ALL, HD and NHL groups. SerumVEGF level correlated significantly with glandular enlargement in ALL, HD and in NHL groups, and with hepatomegaly in ALL and NHL groups. It can be concluded that serumVEGF may have a clinical relevance in the diagnosis and follow up of children with hematological malignancies and raises the possibility of using angiogenesis inhibitors as a novel therapeutic strategy in childhood hematological malignancies.
Phenotypic and genotypic study of extended spectrum b-Lactamase producing isolates in nosocomial urinary tract infectionSource: Molecular Diagnosis and Vaccines 2, pp 45 –55 (2004)More Less
Extended spectrum ?-lactamase (ES?L) producing organisms are a problem in hospitalized patients suffering from nosocomial infections (UTI). Urinary tract infection is the most frequent nosocomial infection and catheterization is the most frequent risk factor. To study bacterial causes of nosocomial UTI, role of ES?L producing organisms and association between ES?L production and plasmid content of these organisms, we studied 70 catheterized patients (45 males and 25 females). Urine samples were cultivated on selective media with subsequent antimicrobial susceptibility tests for isolates. Screening for ES?L producing organisms was done using the modified three-dimensional method, E-test, disc diffusion method and plasmid profile analysis. Catheter associated infection was found in 42 (60%) cases, and was more prevalence among males than females. Infection was common among those with long catheter duration and hospital stay. Candida was the commonest organism causing infection followed by gram negative bacilli and Staph. aureus. The most effective antibiotics were Ceftazidime, Tobramycin, Amikacin, Cefotaxime and Vancomycin against E. coli, P. mirabilis, Ps. aeruginosa, K. pneumoniae and Staph aureus respectively. Among the infected cases, extended spectrum ? lactamase activity was present in 13 isolates (31%), and included E. coli (20%), P. mirabilis (30%) and Ps. aeruginosa (16.7%). Good agreement was found between the E. test and the three-dimensional method for detection of ES?Ls. Plasmids of different molecular weights were detected in 61.5% of ES?Ls. There was no particular association between plasmid content and ES?L activity in Proteus mirabilis and Pseudomonas aeruginosa isolates.