Medical Microbiology

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Browsing Medical Microbiology by Author "Abebe, Tamrat (PhD)"

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    Antibody Level Against HBV After Hepatitis B Vaccination and Sero-Prevalence of HBV in Children in Addis Ababa, Ethiopia
    (Addis Ababa University, 2017-06) Teshome, Seifegebriel; Mihret, Adane(PhD); Abebe, Tamrat (PhD)
    Background: Around two billion people have been infected with HBV worldwide, and more than 240 million are chronic carriers. Vaccine introduction for HBV in children was officially launched by WHO in 1980. Since then the vaccine response level was determined in different countries. However, there is no any study conducted in Ethiopia to assess the response level and effectiveness of HBV vaccine against the virus since the initiation of the vaccine in 2007. Objectives: The aim of the study was to determine antibody level against HBV after hepatitis B vaccination and sero-prevalence of HBV in children in Addis Ababa, Ethiopia. Methods: A cross sectional study was conducted and a multi stage probability sampling techniques was applied. Four hundred and fifty children between the age of 5 and 8 years who are living in three sub cities of Addis Ababa were included. Three to four ml of blood was collected and questionnaire was obtained. Finally ELISA was done to determine antibody level against HBV after hepatitis B vaccination and sero-prevalence of HBV infection in children. Result: The mean age of the children was 7+1(SD) years. Protective antibody levels were detected in 208(54.3%) of children with a slightly high response level in females 98(54.7%) than males 110(53.9%). The overall vaccine coverage was 85.1 %. The protective level is declined as the age of the child increased and it was 52.6%, 60%, 43.5% and 37.1% at the age of 5, 6, 7 and 8 years, respectively. The sero prevalence of HBsAg was 0.4% whereas Anti HBc was 5.6%. Age has negatively correlated and significantly associated with the response level (p=0.001) whereas sex and previous disease status of the child has no significant association. Age of the child was also having significant association with sero- prevalence of anti HBc (p=0.003). Other factors like vaccination status and dose of vaccination were also significantly associated with a vaccine response level (p=<0.001). All partially vaccinated children didn’t respond to the vaccine. Conclusion: The vaccine coverage in the country is worthy but antibody response against HBV vaccine is low. We also showed a low Sero- prevalence of the virus in children. However, the low response level to the vaccine should have to be the concern and revaccination or booster doses should be given for non responded children in order to enhance the vaccine response. Key words: HBV, antibody response level, vaccination status, HBsAg, Anti HBsAg, Anti HBc
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    Phenotypic and Molecular Characterization of Uropathogenic Escherichia Coli from Urinary Tract Infection Patients in Selected Health Facilities of Addis Ababa, Ethiopia
    (Addis Ababa Universty, 2018-07) Regasa, Belayneh; Abebe, Tamrat (PhD)
    Introduction: Urinary tract infection (UTI) is major causes of morbidity and mortality worldwide. Uropathogenic Escherichia coli (E. coli) bacterium is responsible for majority of (50-80%) cases of UTI. Drug resistant E. coli is a significant threat to effective treatments. Uropathogenic E. coli strains derive from different phylogenetic groups and possess an arsenal of virulence factors that contribute to their ability to overcome different defense mechanisms and cause disease. Despite its public health importance, data regarding the molecular characteristics of uropathogenic E. coli is lacking in Ethiopia. Therefore, for proper treatment and management of UTI; it is essential to determine drug resistance patterns, phylogroup and virulence genes of E. coli. Objective: To assess the phenotypic and molecular characteristics of uro pathogenic E. coli as well as relationship of virulence genes and drug resistance patterns of uropathogenic E. coli among patients with UTI in selected health facilities of Addis Ababa, Ethiopia. Methods: A cross sectional facility based study was conducted on 780 patients with urinary tract infections visiting Tikur Anbessa Specialized Hospital (N=580), Yekatit 12 Hospital (N=30) and Zewditu Memorial Hospital (N=170), Addis Ababa, Ethiopia from January 1, 2017 to October 9, 2017 using a well-designed questionnaire and microbiological investigations. Uropathogenic E. coli bacteria were isolated from urine samples using bacterial culture and conventional biochemical tests. Phenotypic drug resistance patterns and plasmid profile was determined using Kirby Bauer disc diffusion and plasmid analysis respectively. Identification of phylogroup and genes that encodes for virulence factors was done using multiplex polymerase chain reaction (PCR). Data was processed and analyzed with SPSS version 16.0 and EPI info version 3.4.1 softwares. P-value less than 0.05 were considered significant. Result: Among 780 UTI patients, 200 uropathogenic E. coli bacteria were isolated. E. coli isolates had highest resistance (86.5%) to ampicillin followed by ceftazidime (84%), ceftriaxone (80.5%), tetracycline (80%), trimethoprim-sulfamethoxazole (68.5%) and cefotaxime (66%). Highest susceptibility to meropenem (100%) and imipenem (100%) were observed. E. coli isolates were susceptible to amikacin (97.5%), nitrofurantoin (95%), ciprofloxacin (85.5%), norfloxacin (85%), chloramphenicol (83.5%), gentamicin (80%) and nalidixic acid (79%). Multidrug resistance (MDR) was observed to most (96.5%) E. coli isolates. Plasmid analysis showed the presence of plasmid/s in 165 (82.5%) E. coli isolates. Majority of tested E. coli isolates had upto 10 plasmids, the size of which commonly 23kb. The most frequent E. coli virulence gene amplified was fim H 164 (82%), followed by aer 109 (54.5%), hly 103 (51.5%), pap 59 (29.5%), cnf 58 (29%), sfa 50 (25%) and afa 24 (12%). Significant association (p-0.014) between fim H and chloramphenicol drug resistance as well as between aer genes, and gentamicin, ampicillin and nitrofurantoin drug resistance (p-0.028, p-0.018 and p-0.023 respectively) was observed. There was significant association between pap gene and urine urgency (p-0.016); sfa, and dysuria and urine urgency (p-0.019 and p-0.043 respectively); hly and suprapubic pain (p-0.002); aer and suprapubic pain, flank pain and fever (p-0.017, p-0.040, p-0.029 respectively). Majority of E. coli isolates were phylogroup B2 60 (30%) followed by D 55 (27.5%), B1 48 (24%) and A 37 (18.5%). Conclusion: The overall incidence of antimicrobial resistant (including MDR) E. coli in this study was high to commonly used antibiotics but none to carbapenems. The virulence genes encoding components of adhesins, iron acquisition systems, and toxins were highly prevalent. Majority of E. coli isolates were phylogroup B2 followed by D. Therefore, periodic monitoring of drug resistance patterns and targeting major virulence genes as potential vaccine candidates is essential for better management of UTI and further large scale studies should be conducted in this area.