Medical Microbiology

Permanent URI for this collection

http://etd.aau.edu.et/handle/123456789/69

Browse

Now showing 1 - 14 of 14

Arginase Activity in the Blood of Patients with HIV, TB and HIV/TB Co-infections
(Addis Ababa University, 2015-09) Abdu, Mohammedmensur; Abebe, Tamrat(PhD); Mihret, Adane(PhD)
Background: HIV/AIDS and TB remain a major global public health problem and their global distribution is heavily skewed toward low income and emerging economics. Africa, and more specifically Sub-Saharan Africa, faces the worst epidemic of the two diseases since the advent of the antibiotic era. Both TB and HIV have profound effects on the immune system, as they are capable of disarming the host’s immune responses through mechanisms that are not fully understood. The catabolism L-arginine by arginase has emerged as a potent mechanism for the regulation of immune responses. Objectives: To measure arginase activity in the blood of patient with HIV, TB and HIV/TB coinfected patients at Zewditu Memorial and St. peter's Hospital, Addis Ababa, Ethiopia. Methodology: A cross-sectional study was conducted from April 2014 to October 2014.Venous blood was collected from patients before initiation of treatment and controls in BD Vacutainer EDTA tubes. Isolation of peripheral blood mononuclear cells (PBMC) is performed by density gradient centrifugation on Histopaque-1077(Sigma) where as Plasma was obtained after centrifugation of a blood at 1800 rpm for 10 minutes. Arginase enzyme activity was determined using colorimetric assay based on color formed when urea produced is heated in acid with - isonitrosopropiophenone. Data were evaluated by using GraphPad Prism version 6.05 and the differences were considered statistically significant at p < 0.05. Result: Increased arginase activity was observed in PBMC of HIV, TB and HIV/TB co-infected patients than in PBMC of healthy controls and similarly higher arginase level also measured in plasma of TB and HIV/TB co-infected patients than in plasma of healthy control. Moreover, a CD+4 T cell counts of HIV and HIV/TB co-infected patients and BMI of HIV, TB and HIV/TB patients were negatively associated with PBMC arginase activity. Conclusion: Our results suggest that arginase activity is become higher during HIV, TB and HIV/TB co-infections. Keywords: PBMC, plasma, HIV, TB, HIV/TB patients, Arginase
Blood Neutrophil Count, Sputum Mycobacterial Load and Mycobacterial Lineages in HIV Positive Individuals Suspected with Pulmonary Tuberculosis, Addis Ababa, Ethiopia
(Addis Ababa University, 2015-12) Debela, Negeri; Abebe, Tamrat(PhD); Mihret, Adane(PhD)
Background: The protective and pathologic response of host to M.tuberculosis is complex and multifaceted, involving many components of the immune system. There are evidences which suggest that neutrophils play a role in the host response to M.tuberculosis. In patients with established tuberculosis (TB) disease, higher peripheral blood neutrophil counts are associated with delayed mycobacterial clearance from sputum and worse clinical prognosis. Objective: To determine neutrophil counts in peripheral blood of HIV positive individuals with suspected pulmonary tuberculosis(PTB) and to find out the association with mycobacterial load and mycobacterial lineage in Zewoditu-Memorial Hospital and Federal Police Hospital, Addis Ababa, Ethiopia. Methods: A cross-sectional study was conducted from January 2014 to July 2014. EDTA (Ethylene Diamine Tetra Acetic Acid) anti-coagulated venous blood and sputum samples were obtained. Blood absolute neutrophil counts (ANC) were determined using Cell Dyn 1800 automated hematology analyzer. Sputum samples were decontaminated using sodium hydroxide, which were then concentrated by centrifugation. Smears were prepared from the pellet and stained with ZN (Ziehl-Neelsen) stain for microscopy. The remaining sputum pellets were then used for culture, using LJ (Lowenstein-Jensen) medium. Isolates were also heat killed for molecular genotyping and characterized using spoligotyping. Statistical analyses were done using SPSS and statistical tests were significant at p<0.05. Result: Among 117 participants, the median blood neutrophil count was 2.70x103cells/μl (IQR, 2.1–3.7). PTB was confirmed in 28 out of 117 participants. Patients with PTB had a median blood neutrophil count of 4.06x103/μl (IQR, 3.22–5.91) compared to 2.56x103 cells /μl (IQR, 2.1–3.1) among those who were PTB negative (p<0.05). Participants with low mycobacterial load had median ANC values of 3.5x103cells/μl (IQR, 2.6–4.2) and those participants with high mycobacterial burdens had ANC values of 5.5x103cells/μl (IQR, 3.9–7.4) (p<0.05). Participants infected with modern mycobacterial lineage had higher blood ANC than those infected with ancient lineage (p=0.41). Conclusions: Increased blood neutrophil counts were observed among PTB positive individuals and among individuals with high sputum mycobacterial load. Keywords: Neutrophils count, HIV, Pulmonary tuberculosis, sputum mycobacterial load, mycobacterial lineage
A Comparative Study of Blood Culture and Widal Test in the Diagnosis of Typhoid Fever in Febrile Patients
(Addis Ababa University, 2011-06) Andualem, Gizachew; Abebe, Tamrat(PhD); Kebede, Negatu(PhD)
Introduction: Typhoid fever is a major health problem in developing countries. An accurate diagnosis on clinical grounds alone is difficult. In areas of endemicity, such as Ethiopia, bacterial culture facilities, definitive diagnosis for typhoid fever, are often unavailable. So, the Widal test has been in use as the diagnostic assay. However, the value of the test for the diagnosis of typhoid fever has been debated. So evaluating the result of Widal test is necessary for correct interpretation of the result. In addition typhoid fever caused by multidrug resistant strains of Salmonella typhi presents a serious problem in many developing countries. Objective: The main objective of this study is to compare the result of Widal test and blood culture in the diagnosis of typhoid fever in febrile patients and to determine the antimicrobial pattern of isolates. Methodology: Data was collected from 277 febrile patients with symptoms clinically similar to typhoid fever visiting St. Paul’s General Specialized Hospitals from mid December 2010 to March 2011. Blood was inoculated immediately after collection into 45ml of Trypton Soy Broth and further processed for the identification of S.typhi and S.paratyphi. Antimicrobial susceptibility pattern of S. typhi and S. paratyphi isolates were determined by the modified Kirby-Bauer disk diffusion technique. Slide agglutination test as screening test and tube agglutination for the determination of antibody titer for reactive slide agglutinations samples have made. An antibody titer of ≥1:80 for anti TO and ≥1:160 for anti TH are taken as a cut of value to indicate recent infection of typhoid fever. Statistical software package for widows (SPSS version 16) was used for analysis of the data and p value ≤0.05 was taken as significance. Result: A total of 277 febrile patients were recruited for this study, but data from 270 were analysed because the remaining seven patients have no full data to be processed. 186 (68.9 %) were females and 84 (31.1 %) were males. 7 (2.6%) cases of S. typhi and 4 (1.5%) cases of S. paratyphi were identified with the total prevalence of typhoid fever 4.1 %. The total number of patients who have indicative of recent infection by either of O and H antigens Widal test is 88 (32.6%). The sensitivity, specificity, PPV and NPV of Widal test are 71.4 %, 68.44%, 5.7% and 98.9% respectively. Most (3/7[42.9%]) of the isolated S.typhi are highly resistant to amoxicillin. All species are sensitive for norfloxacin and ceftriaxone. S. paratyphi isolates show no resistance to gentamycine, tetracycline, norfloxacin and ciprofloxacin. More resistance (3 out of 4) is observed in amoxicillin. One species of S.typhi and 2 species of S. paratyphi are multi drug resistant. Conclusion and recommendation: Widal test have a low sensitivity, specificity and PPV, but it has good NPV which indicates that negative Widal test result have a good indication for the absence of the disease. Hence, physicians should not totally depend on Widal test for the diagnosis of typhoid fever and should use other alternative diagnostics such as clinical knowledge to differentiate from other febrile infections. Regarding drug resistance both S. typhi and S. paratyphi showed high resistance for commonly used drugs against typhoid fever. Therefore, sensitivity test based prescription should be started to prevent the continuous drug resistance development. Key words: Widal test, blood culture, antimicrobial resistance, sensitivity, specificity, positive predictive value, negative predictive value
Detection and Characterization of Mycobacterium Tuberculosis in Stool of HIV Sero-Positive Patients with Suspected Pulmonary Tuberculosis
(Addis Ababa University, 2015-03) Eshetu, Gizaw; Mihret, Adane(PhD); Abebe, Tamrat(PhD); Ameni, Gobena(PhD)
Background: Tuberculosis (TB) in Africa is increasing because of the human immunodeficiency virus (HIV) pandemic, and in HIV ⁄ AIDS patients, it presents atypically. Smear-negative pulmonary tuberculosis (PTB) is more common in HIV-infected patients and leads to diagnostic delay, which increases morbidity and mortality in people living with human immunodeficiency virus (PLHIV). Objective: To detect and characterize Mycobacterium tuberculosis in stool of HIV sero-positive patients with suspected pulmonary tuberculosis. Method: Institutional based cross-sectional study of PTB diagnosis among PLHIV from stool sample was carried out from January 2014 – July 2014. During the data collection period, a total of 117 PLHIV suspected to be suffering from PTB was recruited. Microscopic examination, culture, and PCR were performed to detect and characterize M. tuberculosis. The presence of M. tuberculosis was compared in sputum and stool samples simultaneously collected from patients suspected for pulmonary tuberculosis. Data was entered and cleared using EpiData version 3.1, then exported to SPSS version 20 for analysis. Results: Of the 117 patients suspected of having PTB, 33 (28.2%) were sputum culture positive. Of these, 10 (30.3%) were sputum and stool culture positive for M. tuberculosis. Of the 84 sputum, culture negative cases, three (3.6%) were stool culture positive with measure of agreement 0.328. Eleven of 117(9.4%) patients were positive by sputum smear. Of 11 (9.4%) sputum, smear positive, three (27.3%) were both sputum and stool smear positive for M. tuberculosis. Of the 106-sputum smear negative, stool smear permitted the diagnosis of one (1%) PTB patient though the sensitivity (12.1%) was very low and kappa value of 0.18. As compared to sputum culture, the sensitivity of stool PCR was 69.7% with substantial agreement 0.67. Sputum PCR detected additional 4/81 (4.9%) from the bacteriologically negative PTB patients. We did spoligotyping and T family (43.5%), family 33 (41.3%), CAS family (4.3%), H family (4.3%), H37Rv family (4.3%) and Beijing family (2.2%) were isolated. Conclusion: M. tuberculosis was detected in stool of PLHIV. Hence, examination stool sample along with sputum sample increases diagnoses of PTB in PLHIV
Enteric Pathogens and Antimicrobial Susceptibility Profile Among Pediatric Patients with Diarrhea: A Cross Sectional Study in Selected Health Facilities, Addis Ababa, Ethiopia
(Addis Ababa University, 2017-06) Ayenew, Zeleke; Gebre-Selassie, Solomon(PhD); Abebe, Tamrat(PhD)
Background: Diarrheal disease remains a major public health problem in developing countries including Ethiopia. The current study was designed to isolate medically important enteric pathogens and assess the antimicrobial susceptibility testing of bacteria causing diarrhea in pediatrics for those antibiotics were prescribing in Integrated Management of Childhood illness (IMCI). Methods: Across-sectional study to determine enteric pathogenic microorganisms that cause diarrhea and antimicrobial susceptibility profile was carried out in selected health facilities of Addis Ababa, Ethiopia from November 2016 to May 2017. Stool specimens from pediatric patients aged 0-14 years were collected randomly from two health centers and one specialized hospital to identify enteric pathogens. Antimicrobial susceptibility tests were performed on all bacterial isolates using the Kirby-Bauer disc diffusion method. Results: In this study, the major etiologic agents of diarrhea in pediatrics were intestinal parasites and bacterial infection accounting for 93(32%) and 42(14.5%) respectively. Out of 290 study patients complain of diarrhea examined, E.histolytica/dispar 75(25.8%), G.lamblia 13(4.5%) and H.nana 4(1.4%) were identified. The majority of bacterial enteropahogens isolated in the study were Shigella spp 22(7.6%) followed by enterohemorrgic E.coli O157:H7 13(4.5%), Salmonella spp 7(2.4%). The overall co-infection rate between parasite-parasite, parasite-bacteria and bacteria-bacteria was observed in 12(4.1%) children. All the bacterial isolates from diarrheal patients were 100% susceptible to meropenem, cefepime, azithromycin and showed antimicrobial resistance to ampicillin, Augmentin, trimethoprim-sulphamethoxazole and ciprfloxacillin. Salmonella spp showed resistance to trimethoprim-sulphamethoxazole and chloramphenicol, 42.9% and 14.3% respectively. Another enteric bacteria Shigella spp were resistant to 77.3%ampicillin, 68.2% trimethoprim-sulphamethoxazole and 36.4%Augmentin whereas E.coliO157:H7 resistance anti-biogram showed 69.2%ampicillin,46.1% trimethoprim-sulphamethoxazole,38.5%Augmentin, 23.1%ciprfloxacillin and Amikacin, ceftriaxone and gentamycin were resistant with the same rate of 15.4%.. Conclusion: The results showed that E.histolytica, G.lamblia and H.nana and bacterial isolates Salmonella spp, enterohemorrhagic E.coli O157:H7, Shigella spp were the most frequently isolated pathogens in Children. The most frequently prescribing drugs ampicillin, amoxicillin+clavulic acid and trimethoprim-sulphamethoxazole showed high resistance for Salmonella and Shigella isolates in the study. It was found that ciprofloxacin was the best drug of choice for the treatment of diarrhea caused by Salmonella and Shigella. Chloramphenicol was a drug of choice for the treatment of shigellosis. So it calls more attention to conduct extensive continuous surveillance to revise and update the prescribing policy in Integrated Management of Childhood illness and Clinicians should rely on stool culture and antimicrobial susceptibility testing. Key words: Enteric pathogens, diarrhea, antimicrobial susceptibility, pediatrics, Addis Ababa, Ethiopia
Isolation and Antibiotic Susceptibility of Shigella and Campylobacter from Acute Enteric Infections in Yekatit 12 Hospital and Shiromeda Health center, Addis Ababa
(Addis Ababa University, 2011-06) Worku, Getnet; Abebe, Tamrat(PhD); Mihret, Adane(PhD)
Background -Acute infective diarrhoea and gastroenteritis are major causes of ill health and premature death in developing world due, in large part, to the lack of safe drinking water, sanitation and hygiene, as well as poorer overall health and nutritional status. Among the leading causes of infectious diarrhoea, Campylobacter and Shigella contribute a lot. Antimicrobial resistance has developed among many of the major diarrheal bacterial pathogens and complicated the selection of antibiotics for the treatment of enteric bacterial pathogens, particularly to commonly used antimicrobial agents such as ampicillin, tetracycline and trimethoprim–sulfamethoxazole. Objective - To isolate and determine antibiotic susceptibility pattern of Shigella, and Campylobacter from acute enteric infections in Addis Ababa Method - A cross sectional study was conducted from December 2010 to March 2011 at Shiromeda health center (n=254) and Yekatit 12 Hospital (n=140). All diarrheal stool specimens were cultured for isolation of Shigella and Campylobacter species. Antimicrobial susceptibility testing was performed for culture isolates according to the method of Clinical and Laboratory Standards Institute (CLSI) by disk diffusion method. Result – A total of 163 enteropathogens were isolated from 394 patients that had acute diarrhea. The isolates were 37 (9.4%) Shigella species, 19 (4.8%) Campylobacter species, 23 (5.8%) Salmonella species and 84 (21.3%) parasites. 192 (48.7%) of the patients were females and 202 (51.3%) were males making the female to male ratio 1:1.05. The antimicrobial susceptibility pattern for 37 strains of Shigella isolates showed 67.6% resistance to ampicillin followed by, trimethoprim-sulfamethoxazole (64.7%), and chloramphenicol (40.5%). More than 90% of the strains were sensitive to nalidixic acid ciprofloxacin, norfloxacin and polymyxin B. Multiple resistances (resistant to two or more drugs) were observed in 23 (62.1%) of the isolates. All Campylobacter spp. were susceptible to chloramphenicol and showed low resistance rates (<60%) against, trimethoprim-sulfamethoxazole, ampicillin, nalidixic acid, ciprofloxacin and erythromycin. Conclusion- the results of the present study showed the high prevalence for Shigella spp. while Campylobacter spp. showed a moderate one. Continuous surveillance of the prevalence and VIII antibiotic susceptibility pattern of diarrheal bacteria in hospitals and in the community is needed which should be the basis for empiric therapy
Molecular Epidemiology and Comparison of Diagnostic Methods of Tuberculous Lymphadenitis, Addis Ababa, Ethiopia
(Addis Ababa University, 2014-05) Zewdie, Olifan; Abebe, Tamrat(PhD); Mihret, Adane(PhD)
Extrapulmonary tuberculosis is a significant health problem worldwide because of difficulties in its diagnosis and in monitoring its treatment, in which tuberculous lymphadenitis is high prevalent. To this effect, adequate knowledge on the species and strains of mycobacteria which circulate among the human population in specific geographic location is required. Objective: The objective of this study was to determine the prevalence of TBLN and to compare diagnostic performance of laboratory methods in diagnosis of TBLN among clinically suspected TBLN patients; identify the dominant species/ strain of M.tuberculosis responsible for TBLN. Materials and Methods: A cross-sectional study was conducted between February,2013 to October, 2013. Structured questionnaire, fine needle aspiration cytology and histopathology, Ziehl Nelson staining, mycobacterial culture, region of difference (RD)-PCR, spoligotyping and flowcytometry were used for undertaking this study. SPSS version 20 was used for data entry and analysis. Result: Of the 206 TBLN suspected cases, 166 (80.6%) were positive for TBLN by FNAC and histopathological examinations. On the other hand, only 36% (74/206) were positive by mycobacterial culture. Acid-fast bacilli (AFB) were detected in 28.6% of the 133 TBLN suspected individuals while 79.3% of the 121 TBLN suspected cases were positive for mycobacteria by PCR. Majority (98.6%) of the causative agent of TBLN was M.tuberculosis. Further characterization of 74 isolates to strain level by spoligotyping, 57 isolates were classified into one of the 26 shared international types (SITs) according to SpolDB4.0 and the remaining 16 isolates generated 13 different spoligotype patterns which had not been reported to the SpolDB4.0.The most prevalent strains of M. tuberculosis isolated in this study were SIT149, SIT53, SIT26 and SIT37 comprising 52.6% of the total strains. The strains were further classified into families in which the most prevalent were T, CAS and Haarlem comprising of 81.1% of the isolates. Classification of the strains into lineages leads to indicated modern lineage was the most prevalent comprising 66.2%. Conclusion: In this study it has been shown that, several clusters and new strains of M. tuberculosis circulate in TBLN patients in Ethiopia. As mapping the population structure of M. tuberculosis is vital to understand the transmission and disease dynamics of TB and set appropriate control measure. XII Key Words: Tuberculosis lymphadenitis, MTC, RD9 and RD4 Typing, Spoligotyping, Mycobacterium family, Mycobacterium lineage, Phenotyping and Addis Ababa
Molecular Epidemiology and Drug Sensitivity of Mycobacterium Tuberculosis Isolates Among New Pulmonary Tuberculosis Patients in Arsi Zone Oromiya Region, Ethiopia
(Addis Ababa University, 2016-10) Tamrat, Fekadu; Abebe, Tamrat(PhD); Mihret, Adane(PhD)
Back ground: - The 22 high burden countries accounts 80% of global tuberculosis burden, and Africa alone account 28% of Global TB burden where Ethiopia is at 16th from the world, and 9th from the continent accounting an incidence of 200 cases per 100,000 population according to WHO 2015 Tuberculosis report. According to WHO Global TB report, Ethiopia is ranked 15th among 27 high burden MDRTB and XDR-TB countries. The estimated MDR-TB from new cases was 3.3% according to WHOGTR 2015. Specifically in Arsi Zone, PTB+ case notification in the past fifteen years, from 1997 to 2011 increased from 6.9 to 63 per 100,000 populations. Objective: The objective of this study was to characterize the diversity of Mycobacterium tuberculosis strains circulating and to determine the drug susceptibility of the isolates among new PTB+ patients in Arsi zone, Oromiya region, Ethiopia. Methods: - A cross-sectional study design using quota sampling technique was under taken. All smear positive samples were collected from seven selected health facilities which were stated having higher prevalence TB cases in the zone and parallely, questionnaire was filled for socio demographic analysis. Culture on conventional Löwenstein-Jensen (LJ) media and drug sensitivity test using Line Probe Asay (LPA) was done at Adama Regional Laboratory (ARL). Spoligotyping was done in Aklilu Lemma Institute of Pathobiology (ALIPB), AAU and the isolates were compared with the SpoIDB4 database of the Pasteur Institute of Guadeloupe. Results: A total of 150 smear positive pulmonary TB patients were included in this study of which 130 samples were grown on LJ media. The study participant’s age range was from 6 -72 years with the mean of 29 and (±SD) of 13.25, of which 10 % (15/150) of the study participants were below the age of 15.Molecular characterization showed that104/130(80.0%) were Euro-American, 15/130 (11.5%) Indo-Oceanic, 9/130 (6.9%) Unknown lineage, 1/130(0.8%) West African-1 and 1/130(0.8%) Mycobacterium bovis. Drug Sensitivity Test on Line Probe Assay showed that 2 (1.53%) isolates were mono resistance for Rifampicin, 5 (3.8%) mono resistance for INH, and 3 (2.3%) were resistant for both INH and Rifampicin. Prevalence of MDR from New patients was 5/130 (3.8%). Conclusion: - In this study we have shown that the prevalence of MDR-TB from the new TB patients is 3.8% which is high, and the type of the TB lineage circulating dominantly is Euro-America from which the family of “T” is the most circulating strain indicating that there is a rapid circulation among the society. Keywords: - Mycobacterium tuberculosis, Molecular epidemiology, DST, spoligotyping
Performance Evaluation of MDR-TB Color Plate Test for Rapid Detection of Mycobacterium tuberculosis and Multidrug-resistant Tuberculosis in Resource-limited Setting, Addis Ababa, Ethiopia
(Addis Ababa University, 2017-06) Mekonnen, Biruk; Abebe, Tamrat(PhD); Mihret, Adane(PhD)
Background: Tuberculosis (TB) is a top global public health concern and its controlling program is chiefly hampered by diagnostic difficulties. Timely TB diagnosis and detection of drug-resistant TB has a key significance for both patient management and the disease control. However, the commercially existing diagnostic tools are slow and unaffordable for resourcelimited settings. Objective: The current study was aimed to evaluate the performance of MDR-TB color plate test (color plate test) for rapid concurrent detection of Mycobacterium tuberculosis (MTB) and multidrug-resistant TB (MDR-TB) directly from sputum specimens. Materials and Methods: A cross-sectional, hospital-based diagnostic test evaluation study was conducted from March 2016 to February 2017 at All Africa Leprosy, Tuberculosis and Rehabilitation Training Center (ALERT) hospital and St. Peter’s TB referral hospital in Addis Ababa, Ethiopia. The performance of the color plate test was prospectively compared to the conventional Lӧwenstein-Jensen (LJ) culture and LJ indirect proportional drug susceptibility test (DST), and the molecular GeneXpert MTB/RIF® assay. A paired morning expectorated sputum samples were collected from 147 MDR-TB suspected patients using a convenience sampling technique in both hospitals. One of the two sputum samples is used for diagnosis purpose was tested directly by GeneXpert assay at each respective hospital’s laboratory and internally validated. But, the other sputa were refrigerated (4-80C) and transported to the Armauer Hansen Research Institute (AHRI) TB laboratory where the color plate test and the conventional LJ culture and DST were conducted. Data were analyzed using SPSS version 20, and kappa statistic was applied to test agreement between results of the three assays. Result: Of the 147 sputa, 137 (93.2%) sputa produced interpretable MTB detection results for all the three assays and were included in the analysis. Compared to the conventional LJ culture, color plate test was 93.6% sensitive and 98.3% specific while GeneXpert assay was 96.2% sensitive and 79.7% specific. Moreover, the color plate test had showed a strong agreement with both the conventional LJ culture (95.62%, kappa 0.9114) and GeneXpert assay (89.05%, kappa 0.7756) for the detection of MTB. Moreover, all conventional LJ xv culture positives, 78 isolates were further subjected to conventional DST, and valid results obtained by color plate test and Gene Xpert assay were 70 and 72 isolates respectively. The color plate test demonstrated sensitivity of 91.3% and 93.6% specific for the detection of isoniazid resistant MTB isolates with strong agreements (kappa 0.8399). However, the accuracy for detection of rifampicin resistance was suboptimal with low agreement (kappa value of 0.08 and concordance 39%). The color plate test was also in low agreement with the GeneXpert assay (38.57%, kappa 0.0773) for detection of RMP drug resistance. In the present study, the results of color plate test can be obtained in a median time of 13 days while the conventional indirect DST method requires an average of 50 days. Besides, the color plate test is simple to use and the cost per test result also minimal relatively. Conclusion: In this study, the color plate test was found to be a good alternative method for screening of TB and selective drug resistant-TB in a timely and affordable way in resourcelimited setting despite limitations of the test need to be addressed before test approvals. Key Words: Color plate test, Conventional LJ culture, Diagnostic performance, GeneXpert assay, indirect proportional DST, Multidrug-resistant tuberculosis, Tuberculosis
Prevalence and Antibiotic Resistance of Enteric Bacterial Pathogens Isolated from Childhood Diarrhea in Ambo Town Public Health Institutions
(Addis Ababa University, 2015-02) Tosisa, Wagi; Mihret, Adane(PhD); Abebe, Tamrat(PhD)
Introduction: Diarrhea particularly due to enteric bacterial pathogen is a major health problem worldwide. In developed countries, it contributes primarily to morbidity but, in the developing world like Ethiopia, it is responsible for morbidity and a high level of mortality, particularly in children below five years of age. Objective:This study aimed to investigate enteric bacterial pathogens from children aged less than five years old with diarrhea in Ambo town public health institutions in order to determine the prevalence of the disease and antimicrobial resistance pattern. Methodology: Stool samples from 239 children less than 5 years of age with diarrhea attending Ambo Town Public Health Institutions was examined at the Ambo University of Microbiology Laboratory, Ambo, West Ethiopia, from January to July 2014.All collected samples were processed for isolation and antibiotic susceptibility testing of Salmonella, Shigella, Vibrio species and other bacterial species using conventional laboratory tests. PCR was done to confirm Salmonella by amplifying a 496-bp genetic sequence of members of the genus Salmonella. Antibiogram test was performed by Kirby Bauer disc diffusion method using ten commonly used antibiotics. Results: From the 239 children screened, enteric bacteria were isolated from 24 (10%). This included;three (1.3%) Shigellaflexinari, two (0.8%) Shigellaboydii,one (0.4%) Shigellasonnei, three (1.3%) Salmonellaspecies, and fifteen (6.3%) otherbacterialspecies.There was no Vibrio species isolated in this study.The highest resistance among the total entrophatogenic bacteria was observed against Ampicillin (95.8%) followed by Tetracycline (70%), Amoxacillin (62.5%), Cotrimoxazoale (58.3%), Chloramphenicol(41.7%), Nalidixic acid (16.7%) and Cefotaxime (4.7%). All isolates were sensitive to Amikacin, Ciprofloxacin and Gentamycin except 3 intermediate. Conclusion: This study suggests that Shigellia, Salmonella and other enteric bacteria species were some of the pathogenic infection among children with diarrhea in ATPHI.The highest prevalence of antimicrobial resistance was to ampicillin followed by Tetracycline and Amoxacillin. Though still at low levels, the major concern from this finding is the emerging resistance of enteric pathogens that was observed to Nalidixic acid and Cefotaxime
Prevalence and Riskfactors of Pneumococcal Colonization of the Nasopharynx Among Children Attending Kindergarten, Bahir Dar, North West Ethiopia
(Addis Ababa University, 2015-04) Bereded, Fetlework; Abebe, Tamrat(PhD); Mihret, Adane(PhD)
Background: One of the most important potential pathogens found in the microflora of the nasopharynx is Streptococcus pneumoniae. S. pneumoniae (pneumococceus) is a major cause of disease, ranging from uncomplicated respiratory tract infections to severe invasive pneumococcal disease (IPD). Objective: The aim of this study was to determine the prevalence of Streptococcus pneumoniae carriage, antimicrobial resistance pattern, and risk factors of pneumococcal colonization of the nasopharynx among children <6 years of age attending kindergartens in Bahir Dar, North West Ethiopia. Methods: A cross-sectional study was conducted from February 2014 to June 2014 in Bahir Dar, Ethiopia. Convenient sampling technique was used to collect the sample. A total of 239 healthy children were enrolled from four governmental and three private kindergartens. A calcium alginate tipped swab on a flexible aluminium shaft was used to collect nasal swab.Standard techniques of culture on blood agar were used to identify S. pneumoniae.The antibiotic susceptibilities of isolates assessed by the disc diffusion method. Data was analyzed using the SPSS version 20.0.Chi-squire tests were used for analysis was used to determine demographic characteristics and prevalence of each isolated organism. A p-value of <0.05 was regarded as statistically significant. Result: The overall carriage prevalence of Streptococcus pneumoniae was 44.8% (n=107) and crowded living (AOR = 0.459; CI, 0.570-2.439), earlier antibiotic use within 2-4weeks (AOR = 8.004 CI, 1136- 56.409), and presence of siblings < 5 years old at home (AOR = 0.467; CI, 0.234-0.933) were associated with pneumococcal carriage. Pneumococcal carriage was not associated with sex, family size, breast-feeding. Six (5.6%) S. pneumoniae isolates were resistant to ceftriaxone, 9 (8.4%) to chloramphenicol, 47 (43.9%) to trimethoprim-sulfamethoxazole (SXT), 17 (15.9%) to erythromycin, 10(9.3%) to penicillin and 24(22.4%) to tetracycline. Ninty three (86.9) S. pneumoniae isolates were susceptible to Ceftriaxone 93(86.9%) and 95(88.8%) were susceptible to Chloramphenicol. Conclusions: Colonization of the nasopharynx in children attending kindergartens in Bahir Dar was high. Half of the isolates of S. pneumoniae were resistant to trimethoprim-sulfamethoxazole (SXT). Key words: Nasopharyngeal carriage; S. pneumoniae; Antimicrobial susceptibility; Children; Ethiopia
Retrospective Study on the Prevalence, Etiological Agents and Associated Risk Factors for Neonatal Meningitis Infection for the Last Ten Years(2001-2010) At Tikur Anbessa Specialzed Hospital, Addis Ababa, Ethiopia
(Addis Ababa University, 2011-07) Abate, Melese; Abebe, Tamrat(PhD)
Background: - Meningitis occurs more commonly during the first month of life (between birth and the first 28 days of life) than during any other subsequent period and it is associated with high morbidity and mortality. The causes of bacterial meningitis in the neonatal period are generally distinct from those in older infants and children and reflect the maternal gastrointestinal and genitourinary flora and the environment to which the infant is exposed. Data on the recent relative magnitude of the neonatal meningitis infection and associated risk factors is insufficient in Ethiopia. Objective: - The aim of this study was to determine the prevalence, etiologic agents for neonatal meningitis infection and associated risk factors in Tikur Anbessa Specialized Hospital. Methods: - This is a retrospective analysis of 2510 CSF and blood specimens submitted to the bacteriology laboratory of Tikur Anbessa Specialized Hospital for culture in the period between Jan, 2001 and Dec, 2010. The study was done from April, 15- June, 2011. Result: - For this retrospective study data were obtain from 1321 males and 1189 females making male to female ratio 1.1:1. Of 2510 total culture 1321(52.63 %%) were from blood and 1189(47.37%) were from CSF. The causative agent had been isolated (414) showing an isolation rate of (16.49%) of the total 2510 meningitis suspected cases; 358(27.10%) were isolated from blood, while 56(4.71%) have been isolated from CSF culture. The numbers of bacterial meningitis cases in each year from 2001 to 2010 were 41, 18, 16,50,54,46,44,45,40 and 56, respectively and the positive isolation rates in the same year were 13.6%, 14.6%, 17.0%, 25.1%, 20.8%, 26.1%, 15.5%, 15.5%, 12.8% and 12.6% respectively. 56 (13.53%) of bacterial pathogen were isolated only in the year 2010. Higher peak had been observed from the year 2004 to 2006. Of 414 positive for neonatal bacterial meningitis cases; the most common isolated pathogens were Coagulase-negative-staph 148(35.75%), S.aureus 65(15.70%), K.pneumoniae 50(12.08%), Acinetobacter 45(10.87%), E.coli 28 (6.76%). Coagulase-negative-staphylococcus was the predominant pathogen accounting for 148(35.75%) of all cases. Whereas S.aureus and K.pneumoniae accounted for 65(15.70%), 50(12.08%) respectively: More than 50% of the pathogens were isolated from neonates having preterm birth and LBW. Of 75 positive cases that have been properly treated; 66(88%) were given a combination of ampicillin and gentamycin. Conclusion:-Coagulase –negative-staphylococcus remains the major causative agent of neonatal bacterial meningitis infection in the study area. More than 50% were isolated from neonates having preterm birth and LBW; hence, preterm birth and LBW were major risk factors for neonatal bacterial meningitis infections. Keywords:-Neonates, bacterial meningitis, coagulase-negative-staphylococcus
Seroprevalence and Associated Risk Factors for Hepatitis B and C Virus Infections Among Apparently Healthy Mothers in Addis Ababa, Ethiopia
(Addis Ababa University, 2017-06) Biazin, Habtamu; Mihret, Adane(PhD); Abebe, Tamrat(PhD)
Background: Viral hepatitis is a global public health problem affecting millions of people every year, causing disability and death. Hepatitis B and hepatitis C viruses are common causes of viral hepatitis. Studies in different parts of the world showed that viral hepatitis due to HBV and HCV causes considerable morbidity and mortality from both acute infection and chronic sequelae including chronic hepatitis, cirrhosis, and hepatocellular carcinoma (HCC). Community based studies about the prevalence of each viral infections among apparently healthy mothers in Ethiopia has not been conducted, particularly in Addis Ababa. Objective: To determine the Sero-prevalence of HBsAg and HCV among apparently healthy mothers and to identify potential risk factors associated with the infections. Methods: A community based cross sectional study was conducted among 454 apparently healthy mothers, in Addis Ababa, Ethiopia from June 2016 to May 2017. A systematic probability sampling method was employed. A structured questionnaire was used to collect data on socio-demographic characteristics and associated risk factors. All samples were tested, using a sandwich third generation enzyme linked Immunosorbent assay for HBsAg, HBcAb, and HCV by using Bio-Rad ELISA kits. Results: Four hundred and fifty four apparently healthy mothers were involved in this study. Sero-prevalence of hepatitis B and C virus infections were found to be 3.7% and 2.0% respectively. One hundred sixty five (36.3%) were found to be positive for HBcAb. None of them was co-infected by these two viruses. Among the assessed variables and clinical presentations, previous history of liver disease ((AOR=5.5 CI (1.8-16.5), history of jaundice (AOR=17.8 CI (4.0-75.5), and family history of liver disease (AOR= 3.2 CI (1.0-10.4) were significantly associated with HBV infection which were important predictors of HBV infection. Marital statuses, consumption of alcohol (AOR=6.9 (1.3-37.0) and history of jaundice (AOR=19.2 (CI 3.5-104.9) were significantly associated with the occurrence of HCV infection. Conclusion: Hepatitis B and C appear to be a major health problem in our community. Our study finding indicated that an intermediate level of hepatitis B and C virus infection among the study groups and routine screening and vaccine schedules (for HBV) may be important. Therefore, screening asymptomatic people is an important instrument in disease detection, prompt diagnosis and intervention. Key words: Hepatitis B and C virus, sero-prevalence, apparently healthy mothers, risk factors
Use of Urine as an Adjunct Specimen for the Diagnosis of Pulmonary Tuberculosis in People Living With HIV in Addis Ababa
(Addis Ababa University, 2015-01) Chemeda, Alemu; Abebe, Tamrat(PhD); Mihret, Adane(PhD)
Background: Tuberculosis is an opportunistic infection that increases the mortality and morbidity in human immunodeficiency virus (HIV) infected individual. The diagnosis of pulmonary tuberculosis (PTB) is usually established by examination of three Zeihl-Neelsen (ZN) stained smears but in HIV infected persons, ZN staining mostly shows negative smear, which do not preclude Pulmonary TB. Since tubercle bacilli or their nucleic acids are expected to be excreted through the kidneys, we were interested to assess spot urine as a supplementary specimen for diagnosing of pulmonary TB. Objectives: The aim of this study was to evaluate urine as an adjunct specimen for the diagnosis of pulmonary tuberculosis in people living with HIV by using different diagnostic methods. Method: A cross-sectional study was conducted on PTB suspected patients infected with HIV from November 2013 to January 2015. A total 234 specimens (117sputum & 117urine) were collected from 117 PTB suspected cases. The collected samples were processed for culture using Lowenstein-Jensen medium and the left were subjected to PCR using RD9 primers. The culture isolates were further analyzed using deletion typing for species identification and multiplex PCR for genus typing and the isolates were characterized using Spoligotyping. Result: Out of 117 PTB suspected HIV infected individuals, sputum culture alone detected more mycobacterial isolates 33 (28.2%) than the urine specimen alone17 (14.5%). Of the 84 sputum culture-negative cases, four (4.8%) were urine culture-positive. Among patients whose pulmonary samples were negative by all bacteriological methods, the urine PCR was positive in 5.2% of the patients. The combination of urine culture and PCR result was comparable with the result of sputum culture with the sensitivity, specificity, PPV and NPV of 87.9%, 100%, 100%, and 79.2% respectively. In our study, the majority of the isolates (86.8%) belonged to two major families: Family33(43.4%) and T family(43.4%). Conclusion: PCR and culture examination of urine specimen from PTB suspected patients significantly improved the detection rate of M.tuberculosis. The distribution of M.tuberculosis isolated from both urine and sputum specimens of the same patients showed difference with 53.8% in their family. Key words: Tuberculosis; Pulmonary tuberculosis; TB HIV infected, Diagnosis; Urine; PCR.

Browse

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

Results Per Page

Sort Options