Department of Microbiology, Parasitology and Immunology

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Abundance and pyrethroid resistance of aedes aegypti mosquitoes collected in selected wards of Muheza district, Tanzania
(Sokoine University of Agriculture, 2022) Bendera, Neema Ally
Aedes aegypti mosquitoes are primary vectors that carry mosquito-borne diseases such as dengue fever, Zika and Yellow fever. Despite mosquito control measures employed in Tanzania such as indoor residual spraying and larvae source management systems, several studies have reported the presence of insecticide resistance. The present study aimed at investigating the abundance of Ae. aegypti and their susceptibility to pyrethroids in Muheza district in Tanga region. A total of 7200 mosquito larvae were collected from selected wards in Muheza district using standard dipping method and reared into adults. Some of the reared larvae died and others escaped during the rearing process leaving 2572 of the collected larvae that emerged into adults. Adult mosquitoes were identified using standard taxonomic keys. Female Ae. aegypti mosquitoes aged three to five days old were tested for susceptibility to pyrethroids using WHO guidelines and the insecticides used were permethrin (0.75%), alphacypermethrin (0.05%) and deltamethrin (0.05%). Mosquito DNA was then extracted and voltage-gated sodium channel genes were amplified targeting Domain II and Domain III yielding expected amplicons size of 640 and 740 bp, respectively. Abundant Ae. Aegypti species were from Mbaramo ward representing 21% (n=267), followed by Zeneti representing 19% (n=240), Kwafungo 19% (n=236), Genge 13% (n=161), Ngomeni 12% (n=153), Misozwe 10% (n=131) and Magila 6% (n=78). Tested Ae. aegypti mosquitoes were susceptible to alphacypermethrin and permethrin with a percentage mortality of 100 and 98.75%, respectively, and resisted to deltamethrin with a percentage mortality of 68%. S989P and V1016I point mutations were identified. Increase in Ae. aegypti resistance to deltamethrin is attributed to prolonged use of insecticides as residual sprays and on pyrethroids impregnated bed nets. Ae. aegypti resistance to deltamethrin and high abundance of this specie in some wards pose a high risk for mosquito-borne diseases and this calls for rational vector control measures.
Aedes aegypti abundance, larval indices and risk for dengue virus transmission In Kinondoni district, Tanzania
(BMC, 2022) Ngingo, Baraka L; Mboera, Leonard E. G; Chengula, Augustino; Machelle, Ines; Makange, Mariam R; Msolla, Michael; Mwanyika, Gaspary O; Rugarabamu, Sima; Misinzo, Gerald
Background: Tanzania has experienced periodic dengue outbreaks with increased incidence since 2010. However, there is limited information on vector dynamics and transmission risk in most parts of the country. This study was conducted to determine Aedes mosquito abundance, larval indices and dengue virus infection rate as risk indicators for DENV transmission in Kinondoni district, Dar es Salaam, Tanzania. Methods: A cross-sectional study was conducted in three wards of Kinondoni district in Tanzania between Decem- ber 2019 and January 2020. In each ward, three streets were randomly selected for adult and immature mosquito sampling. The adult mosquitoes were collected using Mosquito Magnet traps, while mosquito larvae and pupae were inspected in water-holding containers in the selected household compounds. The detection of dengue virus (DENV) in female Aedes mosquitoes was done using a one-step reverse transcription–polymerase chain reaction (RT–PCR) method. Results: Of the 1416 adult female mosquitoes collected, Ae. aegypti accounted for 16.8% (n = 238). A total of 333 water-holding containers were inspected and 201 (60.4%) had at least an Aedes larvae or pupae. Water-holding containers supporting the breeding of Aedes larvae and pupae included discarded car tires, flowerpots and small and large plastic containers. The overall House Index, Container Index and Breteau Index were 55.1%, 60.4% and 114.2, respectively. None of the 763 female Aedes mosquitoes tested by RT–PCR was found to be infected with DENV. Conclusion: The presence and abundance Ae. aegypti mosquitoes and the large proportion of water-holding con- tainers infested with the mosquito larvae and pupae put residents of Kinondoni district at high risk of DENV trans- mission. Our findings emphasize the need for continuous mosquito vector surveillance and control to prevent the possibility of future DENV outbreaks in Tanzania.
African animal trypanosomiasis: a systematic review on prevalence, risk factors and drug resistance in Sub-Saharan Africa
(Oxford University Press on behalf of Entomological Society of America, 2022) Okello, Ivy; Mafie, Eliakunda; Eastwood, Gillian; Nzalawahe, Jahashi; Mboera, Leonard E. G.
African animal trypanosomiasis (AAT) a parasitic disease of livestock in sub-Saharan Africa causing tremen- dous loses. Sub-Saharan continental estimation of mean prevalence in both large and small domestic animals, risk factors, tsetse and non-tsetse prevalence and drug resistance is lacking. A review and meta-analysis was done to better comprehend changes in AAT prevalence and drug resistance. Publish/Perish software was used to search and extract peer-reviewed articles in Google scholar, PubMed and CrossRef. In addition, ResearchGate and African Journals Online (AJOL) were used. Screening and selection of articles from 2000–2021 was per- formed according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). Articles 304 were retrieved; on domestic animals 192, tsetse and non-tsetse vectors 44, risk factors 49 and trypanocidal drug resistance 30. Prevalence varied by, host animals in different countries, diagnostic methods and species of Trypanosoma. Cattle had the highest prevalence with Ethiopia and Nigeria leading, T. congolense (11.80– 13.40%) and T. vivax (10.50–18.80%) being detected most. This was followed by camels and pigs. Common di- agnostic method used was buffy coat microscopy. However; polymerase chain reaction (PCR), CATT and ELISA had higher detection rates. G. pallidipes caused most infections in Eastern regions while G. palpalis followed by G. mortisans in Western Africa. Eastern Africa reported more non-tsetse biting flies with Stomoxys leading. Common risk factors were, body conditions, breed type, age, sex and seasons. Ethiopia and Nigeria had the highest trypanocidal resistance 30.00–35.00% and highest AAT prevalence. Isometamidium and diminazene showed more resistance with T. congolense being most resistant species 11.00–83.00%.
Anti-TB drug resistance in Tanga, Tanzania: A cross sectional facility-base prevalence among pulmonary TB patients
(2015-11) Hoza, A. S.; Mfinanga, S. G. M.; Konig, B.
Objective: To determine the prevalence and risk factors associated with drug resistance tuberculosis (TB) at facility-base level in Tanga, Tanzania. Methods: A total of 79 Mycobacterium tuberculosis (MTB) isolates included in the study were collected from among 372 (312 new and 60 previously treated) TB suspects self-referred to four TB clinics during a prospective study conducted from November 2012 to January 2013. Culture and drug susceptibility test of the isolates was performed at the institute of medical microbiology and epidemiology of infectious diseases, University hospital, Leipzig, Germany. Data on the patient's characteristics were obtained from structured questionnaire administered to the patients who gave informed verbal consent. Unadjusted bivariate logistic regression analysis was performed to assess the risk factors for drug resistant-TB. The significance level was determined at P < 0.05. Results: The overall proportions of any drug resistance and MDR-TB were 12.7% and 6.3% respectively. The prevalence of any drug resistance and MDR-TB among new cases were 11.4% and 4.3% respectively, whereas among previously treated cases was 22.2% respectively. Previously treated patients were more likely to develop anti-TB drug resistance. There was no association between anti-TB drug resistances (including MDRTB) with the risk factors analysed. Conclusions: High proportions of anti-TB drug resistance among new and previously treated cases observed in this study suggest that, additional efforts still need to be done in identifying individual cases at facility-base level for improved TB control programmes and drug resistance survey should continuously be monitored in the country.
Antibiogram and diversity of extended-spectrum beta-lactamase genes in scavenging local chicken in Morogoro municipality, Tanzania
(Excellent publishers, 2020-02-20) Armah, Emmanuel Odartei; Tuntufye, Huruma Nelkiwe
The poultry industry, especially chicken production has in recent times faced a major set-back due to devastating effects of APEC Extended Spectrum Beta- Lactases (ESBL) producing organisms. This research aimed at investigating antimicrobial susceptibility profile and diversity of ESBL producing avian pathogenic Escherichia coli(APEC) among fecal cloacal swaps of scavenging local chickens based on the various housing systems. The APEC isolates were determined by virulence factor profiling and by Kirby-Baeur disc diffusion, 42% of the APEC isolates were found to be ESBL producers. Of the ESBL isolates, 87.5% were resistant to nalidixc acid, 37.5% were resistant to cefotaxime, Trimethroprim-Sulfamethoxazole, augmentnin and cephalothin, 25% were resistant to Ceftriaxone whiles no isolate was resistant to Imipenem, gentamycin and ciprofloxacin. On screening, a total of 32 beta-lactamase genes were found amongst these isolates, all of these isolates harbored the blaTEM gene.Semi-intensively kept chickens harbored more ESBL genes and in more diverse forms than the extensively kept ones.
Antibiogram of avian pathogenic escherichia coli in scavenging local chicken in Morogoro, Tanzania
(2021-04) Armah, Emmanuel Odartei
Avian pathogenic Escherichia coli (APEC) is responsible for the annual million-dollar loss in the poultry industry worldwide. This research aimed at investigating the occurrence and antimicrobial pattern of APEC among scavenging local chickens. A total of 400 cloacal and oropharyngeal swabs were obtained, out of which 192 Escherichia coli were isolated. By use of virulence factor profiling, these 192 samples were screened for the presence of 16 virulence factors by multiplex PCR. All 192 samples harbored at least one of the 16 virulence genes and 19 of them carried at least four, making them APEC. The virulence traits ibeA, iss, traT and chuA were observed to lead the chart with percentages of 84.21, 78.95, 63.16 and and 52.63 respectively. In the pathogenesis of APEC, Iron acquisition, serum resistance, toxins and invasins were found to be very significant (P<0.05). The antimicrobial sensitivity testing, 10.52% of the strains showed multi-drug resistance. All the isolates were sensitive to gentamycin and imipenem drugs whiles none of them were sensitive to cephalothin. Occurrence of virulence strains of APEC in Morogoro region of Tanzania is alarming.
Antigenic differences among porcine circovirus type 2 strains, as demonstrated by the use of monoclonal antibodies
(Journal of General Virology, 2008) Lefebvre, D. J.; Costers, S.; Doorsselaere, J. V.; Misinzo, G.; Delputte, P. L.; Nauwynck, H. J.
This study examined whether antigenic differences among porcine circovirus type 2 (PCV-2) strains could be detected using monoclonal antibodies (mAbs). A subtractive immunization protocol was used for the genotype 2 post-weaning multisystemic wasting syndrome (PMWS)-associated PCV-2 strain Stoon-1010. Sixteen stable hybridomas that produced mAbs with an immunoperoxidase monolayer assay (IPMA) titre of 1000 or more to Stoon-1010 were obtained. Staining of recombinant PCV-2 virus-like particles demonstrated that all mAbs were directed against the PCV-2 capsid protein. Cross-reactivity of mAbs was tested by IPMA and neutralization assay for genotype 1 strains 48285, 1206, VC2002 and 1147, and genotype 2 strains 1121 and 1103. Eleven mAbs (9C3, 16G12, 21C12, 38C1, 43E10, 55B1, 63H3, 70A7, 94H8, 103H7 and 114C8) recognized all strains in the IPMA and demonstrated neutralization of Stoon-1010, 48285, 1206 and 1103, but not VC2002, 1147 and 1121. mAbs 31D5, 48B5, 59C6 and 108E8 did not react with genotype 1 strains or had a reduced affinity compared with genotype 2 strains in the IPMA and neutralization assay. mAb 13H4 reacted in the IPMA with PMWS-associated strains Stoon-1010, 48285, 1206 and VC2002, and the porcine dermatitis and nephropathy syndrome-associated strain 1147, but not with reproductive failure-associated strains 1121 and 1103. mAb 13H4 did not neutralize any of the tested strains. It was concluded that, despite the high amino acid identity of the capsid protein (¢91 %), antigenic differences at the capsid protein level are present among PCV-2 strains with a different genetic and clinical background.
Antimicrobial resistance pattern of escherichia coli isolates from small scale dairy cattle in Dar es Salaam, Tanzania
(MDPI, 2022-07-21) Azabo Rogers R.; Mshana Stephen E.; Matee Mecky; Kimera Sharadhuli I.
In Tanzania, information on antimicrobial resistance in small-scale dairy cattle is scarce. This cross-sectional study was conducted to determine the different levels and pattern of antimicrobial resistance (AMR), in 121 Escherichia coli isolated from rectal swab of 201 apparently healthy small-scale dairy cattle in Dar es Salaam, Tanzania. Isolation and identification of E. coli were carried out using enrichment media, selective media, and biochemical tests. Antimicrobial susceptibility testing was carried out using the Kirby–Bauer disk diffusion method on Mueller-Hinton agar (Merck), according to the recommendations of Clinical and Laboratory Standards Institute (CLSI). Resistance was tested against ampicillin, gentamicin, chloramphenicol, trimethoprim-sulfamethoxazole, tetracycline, nalidixic acid, ciprofloxacin and cefotaxime. Resistance to almost all antimicrobial agents was observed. The agents to which resistance was demonstrated most frequently were ampicillin (96.7%), cefotaxime (95.0%), tetracycline (50.4%), trimethoprim-sulfamethoxazole (42.1%) and nalidixic acid (33.1%). In this case, 20 extended-spectrum beta-lactamases (ESBLs) producing E. coli were identified. 74.4% (90/121) of the isolates were Multidrug resistant (MDR), ranging from a combination of three to 8 different classes. The most frequently observed phenotypes were AMP-SXT-CTX with a prevalence of 12.4%, followed by the combination AMP-CTX with 10.7% and TE-AMP-CTX and NA + TE + AMP + CTX with 8.3% each. The high prevalence and wide range of AMR calls for prudent antimicrobial use.
Antimicrobial use in cattle and poultry production on occurrence of multidrug resistant Escherichia coli. A systematic review with focus on sub-Saharan Africa
(Frontiers, 2022-10-24) Azabo, Rogers; Dulle, Frankwell; Mshana, Stephen E.; Matee, Mecky; Kimera, Sharadhuli
Antimicrobial use in livestock production has been linked to antimicrobial resistance (AMR) worldwide; however, optimization of their use has been considered an important strategy in dealing with it. The aims of this study were as follows: (a) to assess the literature on antimicrobial usage (practices, frequency, class, type) in cattle and poultry production with regard to resistance in Escherichia coli (E. coli) including multidrug resistance (MDR) (b) summarize evidence for quantitative (volumes of active antimicrobial ingredients) and quality (identify and quantify active ingredient) and (c) to identify data gaps. Peer reviewed literature search was conducted by querying two online databases: PubMed and Google scholar from November 15, 2018 to February 2019. The inclusion criteria for eligibility were articles: published in English between 2008 and 2018, including poultry (chicken) or cattle or both, E. coli bacteria of choice, antimicrobial use on farms, quantitative data and quality of antimicrobial used. Microsoft Excel was used for data extraction and Rayyan software for eligibility studies. The search retrieved 1,446 probable articles including those from the reference list of significant papers, of which twenty-four articles remained on full text review with more than a third of the studies being conducted in Nigeria. Farm surveys and antimicrobial sales were identified as the main sources of data and the mean quantities of antimicrobials based on sales data were 23,234, 41,280.87, and 1,538,443 kg of the active ingredient in Nigeria, Zambia and South Africa, respectively. One study from Cameroon determined the quantities of active ingredients based on dose metrics while another study still from Cameroon mentioned the quality of antimicrobials. Tetracyclines, beta-lactams/aminoglycosides and fluoroquinolones were the most common classes of antimicrobials (antibiotics) used. Our review reveals a dearth of information in Sub- Saharan Africa on the quantity and quality of veterinary drugs and yet they play a role in the overall picture of antimicrobial resistance. This finding gives an opportunity in the area of focus for future research as far as resistance and multidrug resistance are concerned in food producing animals.
Assessment of antimicrobial consumption in food animals in Dar es Salaam, Tanzania
(Integrity Research Journals, 2021-10-13) Azabo, Rogers; Matee, Mecky; Kimera, Sharadhuli
Monitoring antimicrobial use in food-producing animals is one of the global strategies to tackle antimicrobial resistance. The purpose of the present study is to generate quantitative information on antimicrobial use pattern in Dar es Salaam, which will be used as an approach for future monitoring and surveillance of antimicrobial quantities consumed in food animals. A 3 years (2016-2018) retrospective survey of antimicrobial usage in food-producing animals in three selected districts of Dar es Salaam city, Eastern Tanzania was conducted. Data on antimicrobial quantities consumed was obtained from five purposively selected licensed veterinary pharmaceutical sales/outlet establishments in the study area, based on keeping detailed sales records for the study period.Data analysis was done using IBM SPSS version20. Animal population data were from FAO-Stat databaseused to extrapolate the quantity consumed in food animals to the entire population during the study period in Tanzania. The antimicrobials were analysed based on class, importance for human medicine and route of administration. The study revealed that 178.4 tonnes of antimicrobials (by weight of active ingredients) were consumed during the 3 years period, with an average of 59.5 ± 3.8 tonnes/year. The commonly consumed antimicrobials were tetracycline (44.4%), sulphonamides (20.3%), aminoglycosides (10.3%) and beta-lactams (7.4%). In relation to veterinary antimicrobial use importance to human medicine, 34.4% were of critically important antimicrobials; 4.1% reserve and 51% watch group according to AWaRe categorization of WHO. Most of the antimicrobials were administered orally. Overall,a mean of 7.44 ± 0.81 mg/PCU (population correction unit) was consumed by food-producing animals during the 3 years period. This finding can help improve monitoring and control of veterinary antimicrobial use in Dar es Salaam in particular and Tanzania in general by preserving the efficacy of antimicrobials for future animal and human generations.
Assessment of the epidemiological status,seroprevalence and molecular detection of Peste des Petits Ruminants in goats and sheep along Tanzania-Malawi Border
(Sokoine University of Agriculture, 2016) Kamwendo, Gladson Chikaiko
Peste des petits ruminants (PPR) is a highly contagious viral animal disease that impact negatively on food security of livestock keepers in Africa due to its fast spread and death of small ruminants. The disease was first reported in West Africa and afterwards Asia, rest of Africa including East Africa and Southern African Development Community (SADC) region. Lack of vaccination and effective application of diagnostic technologies to identify carriers has led to fast spread of the disease. Malawi, Zambia and Mozambique have been warned to be at high risk of infection of PPR due to their proximity to Tanzania and Democratic Republic of Congo (DRC), where the disease has been confirmed (FAO/OIE, 2015). Quantification of the disease status in these high risk countries will ensure effective surveillance and control to keep the disease from spreading. The aim of the present study was to provide epidemiological and molecular status of Peste des PetitsRuminants Virus (PPRV) in small ruminants along Tanzania-Malawi border. Whole blood (n=350), serum (n=350) and nasal swabs (n=100)were collected from goats and sheep in Kyela and Ileje (Tanzania) and Karonga and Chitipa(Malawi). A questionnaire was administered to 113 household heads to depict factors leading to spread of the disease. Molecular diagnosis was done by partial amplification of PPRVgenome using reverse transcription polymerase chain reaction (RT-PCR). Data analysis using chi square test for seroprevalenceand partial logistic regression to check for factors associated with seropositivity were carried out using Epi info statistical package. Based on the results, overall seroprevalencewas 11.1% and analysis showed that 31 out of 83small ruminants (37.3%) in Kyelawas significantly higher (p=0.000) than 8 out of 84 (9.5%) in Ileje. A total of 2 out 95 (2.1%) animals inChitipa had PPRV detected by RT-PCR. However, the PCR products did not yield any nucleotide sequence because the viral load was low. Communal grazing and free roaming husbandry practices were shown to be risk factors for the spread of PPR in these border districts. The interviewed farmers had limited knowledge of the disease although they are helped by Veterinary and field officers for other diseases. It is concluded that there is no active infection of PPR along the border districts of Tanzania and Malawi, however low virus load may be present in Chitipa. It is recommendedthatappropriate strategies should be applied to prevent contact with infected animals through vaccination against PPRVon both sides of border districts.
Assessment of the Immunogenicity of a Novel Live Recombinant Rift Valley Fever arMP- 12ΔNSm21/384 Vaccine Candidate Following Intranasal Vaccination of Goats, Sheep and Calves in Tanzania
(2020-10) Nyundo, S; Adamson, E.K; Rowland, J; Palermo, P.M; Salekwa, L; Matiko, M.K; Bettinger, G.E; Wambura, P; Morrill, J.C; Sullivan, T.R; Watts, D.M
Background: Rift Valley fever virus (RVFV) is an arbovirus that causes morbidity and mortality in livestock and humans throughout Africa and in the Arabian Peninsula. Vaccines are effective for the prevention of Rift Valley fever (RVF) disease, but new and improved vaccines are needed to improve the safety of available vaccines. Also, non- invasive needle free vaccine delivery routes should be evaluated as an alternative for invasive routes of vaccination. Objective: The aim of this proof of concept study was to evaluate the safety and immunogenicity of a novel live attenuated recombinant RVFV arMP-12ΔNSm21/384 vaccine candidate following intranasal vaccination of goats, calves, and sheep in Tanzania. Methods: Healthy, 6-9 months old breeds of African sheep (Ovis aeris), goats (Capra aegagrus) and zebu calves (Bos taurus indicus) were used in this study. The animals were purchased from local livestock keepers in the Mvomero district of Morogoro region, Tanzania. Animals were seronegative to both RVFV and antibody at the time of use in the vaccine trials. Animals in the test group included 10 goats, 7 sheep and 10 calves that were vaccinated in the left nares with 50 μl each and 2 sheep were vaccinated with 100 μl each (50 μl each in the left and right nares) of a dose that contained 4 × 10 5 PFU/50 ul of arMP-12ΔNSm21/384 vaccine, while the control group, including 2 goats, 3 sheep and 2 calves that were injected in the left nares with 50 μl of phosphate buffered saline to serve as placebo controls. Rectal temperature was measured and blood samples were collected on day 14 and 0 before vaccination, and on days 3, 5, 7, 14, 21, 28 and 35 post vaccinations (PV). Serum samples collected on days 14 and 0 before vaccination were tested for RVFV neutralizing antibody by a plaque reduction neutralization test, and on days 3 and 5 PV, serum samples were tested for virus as possible evidence of a viremia in cell culture and weekly collected samples thereafter were tested for RVFV neutralizing antibody. Results: All animals were negative for RVFV neutralizing antibody at 14 and 0 days before vaccination and none of the animals had detectable viremia on days 3 and 5 PV, and none had clinical manifestations throughout the study. Among the 7 sheep, 10 goats, and 10 calves that received 50 μl each of the vaccine dose, 70% had the first detectable antibody on either day 5, 7 or 14 PV with titers ranging from 1:10 to 1:40. The 2 sheep that received the 100 μl each of the virus dose had the first detectable antibody on day 5 PV with a titer of 1:160. Subsequently, animals vaccinated with the 50 μl dose had antibody titers ranged from 1:10 to 640 on days 21, 28 and 35 PV, while those vaccinated with 100 μl maintained an antibody titer of 1:160 throughout the study. Moreover, there was no difference in the antibody titers between animal species p=0.34, although mean antibody titers of goats were highest. Conclusion: As a proof of concept studies, the findings demonstrated that intranasal vaccination is a promising route for vaccinating domestic ruminants with the RVFV arMP-12ΔNSm21/384 vaccine candidate. However, these preliminary results suggested that a larger dose of 4 × 10 5 PFU/100 ul of arMP-12ΔNSm21/384 vaccine needed to be administered to each animal to consistently elicit a robust immune response. Also, further studies are warranted using a larger number of domestic ruminants to confirm the immune response elicited by the larger dose of the vaccine administered via the intranasal route.
Bacteremia in critical care units at Bugando Medical Centre, Mwanza, Tanzania: the role of colonization and contaminated cots and mothers’ hands in cross-transmission of multidrug resistant Gram-negative bacteria
(Antimicrobial Resistance and Infection Control, 2020) Silago, V.; Kovacs, D.; Msanga, D. R.; Seni, J.; Matthews, L.; Oravcová, K.; Zadoks, R. N.; Lupindu, A. M.; Hoza, A. S.; Mshana, S. E.
Background: Multidrug resistance (MDR) is a major clinical problem in tertiary hospitals in Tanzania and jeopardizes the life of neonates in critical care units (CCUs). To better understand methods for prevention of MDR infections, this study aimed to determine, among other factors, the role of MDR-Gram-negative bacteria (GNB) contaminating neonatal cots and hands of mothers as possible role in transmission of bacteremia at Bugando Medical Centre (BMC), Mwanza, Tanzania. Methods: This cross-sectional, hospital-based study was conducted among neonates and their mothers in a neonatal intensive care unit and a neonatology unit at BMC from December 2018 to April 2019. Blood specimens (n = 200) were sub- cultured on 5% sheep blood agar (SBA) and MacConkey agar (MCA) plates. Other specimens (200 neonatal rectal swabs, 200 maternal hand swabs and 200 neonatal cot swabs) were directly inoculated on MCA plates supplemented with 2 μg/ml cefotaxime (MCA-C) for screening of GNB resistant to third generation cephalosporins, r-3GCs. Conventional biochemical tests, Kirby-Bauer technique and resistance to cefoxitin 30 μg were used for identification of bacteria, antibiotic susceptibility testing and detection of MDR-GNB and screening of potential Amp-C beta lactamase producing GNB, respectively. Results: The prevalence of culture confirmed bacteremia was 34.5% of which 85.5% were GNB. Fifty-five (93.2%) of GNB isolated from neonatal blood specimens were r-3GCs. On the other hand; 43% of neonates were colonized with GNB r- 3GCs, 32% of cots were contaminated with GNB r-3GCs and 18.5% of hands of neonates’ mothers were contaminated with GNB r-3GCs. The prevalences of MDR-GNB isolated from blood culture and GNB r-3GCs isolated from neonatal colonization, cots and mothers’ hands were 96.6, 100, 100 and 94.6%, respectively. Significantly, cyanosis (OR[95%CI]: 3.13[1.51–6.51], p = 0.002), jaundice (OR[95%CI]: 2.10[1.07–4.14], p = 0.031), number of invasive devices (OR[95%CI]: 2.52[1.08–5.85], p = 0.031) and contaminated cot (OR[95%CI]: 2.39[1.26–4.55], p = 0.008) were associated with bacteremia due to GNB. Use of tap water only (OR[95%CI]: 2.12[0.88–5.09], p = 0.040) was protective for bacteremia due to GNB. Conclusion: High prevalence of MDR-GNB bacteremia and intestinal colonization, and MDR-GNB contaminating cots and mothers’ hands was observed. Improved cots decontamination strategies is crucial to limit the spread of MDR- GNB. Further, clinical presentations and water use should be considered in administration of empirical therapy whilst awaiting culture results.
Bacterial contaminants of African indigenous leafy vegetables and their antibiotics sensitivity characteristics: A case study of Morogoro Municipality, Tanzania
(Sokoine University of Agriculture, 2017) Kimaro, E. N.
A study was conducted in Morogoro Municipality, Tanzania to investigate the bacterial load found on African indigenous leafy vegetables, their sources and their sensitivity to commonly used antibiotics. A total of 126 samples of fresh African indigenous leafy vegetables (amaranth, nightshade and sweet potato leaves), water used for irrigation from rivers and shallow wells and manure fertilised soils were collected at farm sites and market outlets for bacteriological analysis. Bacterial counts were calculated as colony forming units (CFU) per millilitre (CFU/ml) of vegetable washing. The isolates sensitivity or resistances to antibiotics were determined on Muller – Hinton agar plates by the disk diffusion technique. Data was subjected to Analysis of Variance (ANOVA) using SAS Statistical software. Results showed that microorganisms were abundant on the surfaces of the African indigenous leafy vegetables, with nightshade having 1.8 × 105 CFU/ml while amaranth and sweet potato leaves having 1.7 × 105 CFU/ml and 1.5 × 105 CFU/ml respectively. The water used for irrigation from the lower section of the river had significantly (P = 0.03) higher bacterial loads 1.8 × 105 CFU/ml than water from the higher sections. Biochemical tests indicated bacterial isolates from the studied vegetables to be Escherichia coli, Enterobacter aerogenes, Proteus spp, Staphylococcus albus and Bacillus spp. The results show that Escherichia coli, Enterobacter aerogenes and Proteus spp (coliforms) were highly sensitive (>75 %) to enrofloxacin, sulphamethoxazole and ofloxacin antibiotics but resistant to rifampicin. The observed bacterial loads, and sensitivity patterns to commonly used antibiotics reveal the potential adverse health impact of the vegetables on consumers. Proper handling and preparation of vegetables before consumption is highly recommended. Further research covering different African indigenous leafy vegetables in wider agro-ecological areas and sensitivity patterns to commonly used antibiotics is also strongly recommended.
Batrachochytrium dendrobatidis detected in Kihansi spray toads at a captive breeding facility (Kihansi, Tanzania)
(Inter Research [Commercial Publisher], 2014-09-30) Makange, Mariam; Kulaya, Neema; Biseko, Emiliana; Kalenga, Parson; Mutagwaba, Severinus; Misinzo, Gerald
The chytrid fungus Batrachochytrium dendrobatidis (Bd) is the aetiological agent of amphibian chytridiomycosis, a disease associated with global amphibian population declines. In November 2012, mass mortalities of Kihansi spray toads Nectophrynoides asperginis were observed at the Kihansi captive breeding facility, located in the Udzungwa Mountains, Tanzania. Mortalities increased rapidly, and dead toads showed typical clinical signs of chytridiomycosis, including reddening of the skin that was especially evident on the toe pads. Treatment of toads with itraconazole rapidly reduced mortalities. Dead toads (n = 49) were collected and used to per- form Bd-specific polymerase chain reaction and subsequent nucleotide sequencing. All toads col- lected at the facility were positive for Bd. The obtained Bd 5.8S rRNA gene and flanking internal transcribed spacer regions (ITS1 and ITS2) were not 100% identical to any other Bd sequences in GenBank, but closely resembled isolates from Ecuador, Japan, USA, Brazil, Korea, and South Africa. To our knowledge, this is the first study reporting molecular characteristics of Bd isolated from the Udzungwa Mountains. Strict biosecurity measures at the breeding facility and in Kihansi spray wetlands where toads have been reintroduced have been implemented. Further studies on Bd epidemiology in the Udzungwa Mountains are recommended in order to understand its origin, prevalence, and molecular characteristics in wild amphibian populations. This will be important for conservation of several endemic amphibian species in the Udzungwa Mountains, which are part of the Eastern Arc Mountains, a global biodiversity hotspot.
Binding and entry characteristics of porcine circovirus 2 in cells of the porcine monocytic line 3D4/31
(2005) Misinzo, G.; Meerts, P.; Bublot, M.; Mast, J.; Weingartl, H. M.; Nauwynck, H. J.
Porcine circovirus 2 (PCV2) is associated with post-weaning multisystemic wasting syndrome and reproductive problems in pigs. Cells of the monocyte/macrophage lineage are important target cells in PCV2-infected pigs, but the method of binding and entry of PCV2 into these cells is unknown. Therefore, binding and entry of PCV2 to the porcine monocytic cell line 3D4/31 were studied by visualization of binding and internalization of PCV2 virus-like particles (VLPs) by confocal microscopy and chemical inhibition of endocytic pathways (clathrin- and caveolae-mediated endocytosis and macropinocytosis), followed by evaluation of the level of PCV2 infection. It was shown that PCV2 VLPs bound to all cells, with maximal binding starting from 30 min post-incubation. Bound PCV2 VLPs were internalized in 47±5?0% of cells. Internalization was continuous, with 70?5±9?7% of bound PCV2 VLPs internalized at 360 min post-incubation. Internalizing PCV2 VLPs co-localized with clathrin. PCV2 infection was decreased significantly by chemical inhibitors that specifically blocked (i) actin-dependent processes, including cytochalasin D (75?5±7?0% reduction) and latrunculin B (71?0±3?0% reduction), and (ii) clathrin-mediated endocytosis, including potassium depletion combined with hypotonic shock (50?2±6?3% reduction), hypertonic medium (56?4±5?7% reduction), cytosol acidification (59?1±7?1% reduction) and amantadine (52?6±6?7% reduction). Inhibiting macropinocytosis with amiloride and caveolae-dependent endocytosis with nystatin did not decrease PCV2 infection significantly. PCV2 infection was reduced by the lysosomotropic weak bases ammonium chloride (47?0±7?9% reduction) and chloroquine diphosphate (49?0±5?6% reduction). Together, these data demonstrate that PCV2 enters 3D4/31 cells predominantly via clathrin-mediated endocytosis and requires an acidic environment for infection.
Biological activity of extracts from commiphora swynnertonii against microbes of veterinary importance in chickens
(Sokoine University of Agriculture, 2013) Bakari, Gaymary George
Studies were carried out to establish ethno-botanical information and biological activities of crude extracts from Commiphora swynnertonii against selected microbes of veterinary importance in chickens. Initially, a questionnaire survey was conducted to gather information on practices and knowledge on ethno-botanical uses of C. swynnertonii in the study area. Then extracts from different morphological parts of the study plant were tested against selected bacteria and fungi in vitro using agar well diffusion assay. Resin and root bark extracts showed significant activities (P < 0.001) against S. pyogenes, E. coli and B. subtilis compared to other extracts. The fungi, C. albicans and A. niger, were moderately inhibited. Antiviral activity of the resin and root bark extract was tested in ovo using embryonated chicken eggs inoculated with Newcastle disease virus (NDV). Both extracts significantly (P < 0.001) and effectively reduced virus titres. An animal trial was carried out using the resin and chickens experimentally infected with NDV. Results revealed significant reduction (P < 0.05) in clinical signs and mortality rates following administration of the resin before and after the infection. Prophylactic administration of the extract was found to be more effective than the therapeutic approach. HI titres decreased significantly (P < 0.001) in resin and root bark treated groups and in all chickens treated with resin irrespective of dose given and on whether the extract was administered before or after infection suggesting that the plant materials were capable of destroying the NDV before stimulating the developing chick‘s immunity. Another animal trial investigated the effect of the resin against experimental coccidiosis in chickens. Results showed that oral administration of the resin significantly (P < 0.001) reduced mortality rate. Safety margin of the resin was also investigated by determining its effects on selected physiological and biochemical parameters in chickens. The results revealed a good margin of safety provided that the dosage ranges between 200 to 800 mg resin/kg body weights. A phytochemical study was also carried to determine major bioactive compounds in the resin and root bark extracts. With these studies, it is concluded that extracts from C. swynnertonii especially resin, has significant antibacterial, antifungal, antiviral and anticoccidial effect against the selected microbes. Further research is required to test and validate the extract against other pathogens of medical and veterinary importance.
Cell tropism and entry of porcine circovirus 2
(Elsevier, 2011-11-11) Nauwynck, H.J.; Sanchez, R.; Meerts, P.; Lefebvre, D.J.; Saha, D.; Huang, L.; Misinzo, G.
Porcine circovirus 2 (PCV2) may induce reproductive failure (return to oestrus, embryonic death, mum- mification, weak- and stillborn piglets) and postweaning multisystemic wasting syndrome (PMWS). Furthermore, it may modulate the immunity in such a way that it aggravates the outcome of many bacterial and viral infections. In the present paper, the cellular tropism and entry of PCV2 are described and linked with the pathological and clinical consequences.
Characterization and thermostabilization of avibacterium paragallinarum candidate strains with potential use as candidate vaccine strains in Tanzania
(Sokoine University Of Agriculture, 2013) Chota, Andrew Claud
This study was conducted to isolate, characterize, thermostabilize and develop an easier and cheap technique for preparation of inactivated and live vaccines against Infectious coryza (IC). Fifty six (56) samples were collected from chicken. Fourty eight percent (27) isolates had phenotypic characteristics suggestive of both pathogenic and non-pathogenic Avibacterium species. Fifty nine percent (16) of 27 isolates were catalase negative, oxidase positive and NAD dependent. Moreover, they were positive to fructose, maltose, and sucrose, but negative to lactose and urease suggesting that they were Avibacterium paragallinarum. Identification and serotyping by polymerase chain reaction (PCR) confirmed that they were Av. paragallinarum serovar B. Chocolate broth (CB), a novel medium was used to propagate Av. paragallinarum. The broth’s ability to support growth of Av. paragallinarum was compared to other three routine media and analysed using t- test. Results showed that null hypothesis was accepted between allantoic fluid (AF) and CB and between CB and modified brain heart infusion (MBHI) and was rejected between CB and brain heart infusion (BHI). The cost of production of 1 mL of CB was twenty six (26) times lower than the cost of producing AF and four (4) times lower than MBHI and BHI, therefore, CB is preferred as it is an easy to prepare and cheap medium. Av. paragallinarum isolates were thermostable at room temperature (RT) at the temperature range of 27-290C. The bacteria were recovered after storage for three months at RT in 2.5% gelatin. The findings from the present study have shown that Av. paragallinarum serotype B and other members of the genus Avibacterium exist in Tanzania. Propagation of Av. paragallinarum CB will possibly result in production of vaccines that are cheap and affordable to farmers. Furthermore, preservation of Av. paragallinarum in 2.5% gelatin for 3 months is a significant finding for development of live vaccines against IC.
Characterization of Aeromonads and development of Vaccine candidate from Aeromonas Hydrophila Isolated from Tilapia fish farms in Tanzania
(Sokoine University of Agriculture, 2020) Mzula, Alexanda
Tanzania produces less than half of the country annual demand in fish. Therefore, there is an urgent need to produce more fish, particularly through fish farming. However, aeromonads infections cause major lose in aquaculture worldwide and especially in developing countries, including Tanzania, lacking advanced capacity for fish disease control and prevention. Poor fish farming management practices, lack of data on prevalence, emergence of resistances to commonly used drugs, drug residues and limited capacity to control aeromonads bacterial infections emerged as major health problems in fish farming in Tanzania. This study aimed to characterise the aeromonads species circulating in fish farms and then develop a monovalent vaccine candidate from selected prevalent aeromonads specie for supporting tilapia fish farming improvement in Tanzania. A cross sectional study was conducted in Ruvuma, Mbeya, Iringa and Kilimanjaro regions between February 2017 and October 2018. A questionnaire was administered to 32 selected fish farmers to explore their knowledge on pond, fish health and diseases management practices. The results showed that the selected farmers had limited knowledge on pond, fish health and disease management practices. On- farm training on the same to these farmers would improve their knowledge. A total of 816 whole fish samples were aseptically collected from these 32 fish farms to detect and identify aeromonads using molecular methods in order to establish the prevalence and characterise their virulence properties. The overall prevalence of 24.6% was recorded. Seventy five percent of the isolates had virulence genes of varying combinations and the in-vivo study showed high mortality (98.3%) to isolates with more virulence genes indicating their capacity to establish disease in a favourable environment. The Aeromonas hydrophila strain TZR7- 2018 was selected and attenuated using a novel thermo-continuous sub-culturing method to develop a vaccine candidate. The experimental study was carried out to assess its protective efficacy. The results showed that the vaccine candidate had acceptable protective efficacy of 82.3% and 71.4% when given through intraperitoneal injection (IP) and immersion (IM); respectively. To the best of my knowledge this study reports the development of thermo attenuated and stabilized A. hydrophila vaccine candidate for the first time in Tanzania or elsewhere

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