Browsing by Author "Komba, Erick V. G."

Now showing 1 - 11 of 11

Antimicrobial resistance profiles, virulence genes, and genetic diversity of thermophilic campylobacter species isolated from a layer poultry farm in Korea
(Frontiers in Microbiology, 2021) Gahamanyi, Noel; Yoon, Kye-Yoon; Mboera, Leonard E. G.; Matee, Mecky I.; Mutangana, Dieudonné; Amachawadi, Raghavendra G.; Komba, Erick V. G.; Pan, Cheol-Ho
Thermophilic Campylobacter species are among the major etiologies of bacterial enteritis globally. This study aimed at assessing the antimicrobial resistance (AMR) profiles, virulence genes, and genetic diversity of thermophilic Campylobacter species isolated from a layer poultry farm in South Korea. One hundred fifty-three chicken feces were collected from two layer poultry farms in Gangneung, South Korea. The Campylobacter species were isolated by cultural techniques, while PCR and sequencing were used for species confirmation. Antimicrobial susceptibility testing for six antimicrobials [ciprofloxacin (CIP), nalidixic acid (NAL), sitafloxacin (SIT), erythromycin (ERY), tetracycline (TET), and gentamicin (GEN)] was carried out by broth microdilution. Three AMR and nine virulence genes were screened by PCR. Genotyping was performed by flaA-restriction fragment length polymorphism (RFLP) and multilocus sequence typing (MLST). Of the 153 samples, Campylobacter spp. were detected in 55 (35.9%), with Campylobacter jejuni and Campylobacter coli being 49 (89.1%) and six (10.9%), respectively. High-level resistance was observed for CIP (100%), NAL (100%), and TET (C. jejuni, 93.9%; C. coli: 83.3%). No resistance was observed for SIT. The missense mutation (C257T) in gyrA gene was confirmed by sequencing, while the tet(O) gene was similar to known sequences in GenBank. The rate of multidrug-resistant (MDR) strains was 8.2%, and they all belonged to C. jejuni. All Campylobacter isolates possessed five virulence genes (cdtB, cstII, flaA, cadF, and dnaJ), but none possessed ggt, while the rates for other genes (csrA, ciaB, and pldA) ranged between 33.3 and 95.9%. The flaA-RFLP yielded 26 flaA types (C. jejuni: 21 and C. coli: five), while the MLST showed 10 sequence types (STs) for C. jejuni and three STs for C. coli, with CC-607 (STs 3611) and CC-460 (ST-460) being predominant. Among the 10 STs of C. jejuni, three were newly assigned. The findings of this study highlight the increased resistance to quinolones and TET, the virulence potential, and the diverse genotypes among Campylobacter strains isolated from the layer poultry farm.
Detection and characterization of zoonotic Bartonella spp. in rodents and shrews ectoparasites from Kigoma and Morogoro Regions, Tanzania
(De Gruyter, 2023) Mhamphi, Ginethon G.; Msoffe, Venance T.; Lyimo, Charles M.; Katakweba, Abdul S.; Massawe, Apia W.; Komba, Erick V. G.; Mnyone, Ladslaus L.
Bartonellosis is a vector-borne disease which is increasingly threatening the health of humans and animals worldwide consequent to the growing wildlife-animals- human interactions. Little is known about the epidemiology of this disease in Tanzania. In this study we investigated and characterized Bartonella species in small mammals’ ectoparasites from potentially high-risk areas in the country. A total of 141 ectoparasites pools of mites, fleas, ticks, and lice were analyzed using conventional PCR and sequencing. Bartonella DNA was detected in 34.8 % of the tested ecto- parasite pools, with mites at 32.9 %, fleas at 40 %, ticks at 12.5 %, and lice at 50 %. Phylogenetic analysis showed that the Bartonella spp. genotypes were closely related to those found in Uganda, Kenya, and South Africa. Different geno- types with independent haplotypes were observed, although most Bartonella spp. from fleas shared the same haplogroup. The confirmed presence of Bartonella elizabethae and Bar- tonella tribocorum in field and house rodents emphasizes the prevailing transmission risk of zoonotic infections in the study areas and beyond. Screening of humans, companion animals, and livestock in potentially high-risk areas in Tanzania is necessary in order to inform the development of responsive surveillance and control strategies.
Emodin modulates gut microbial community and triggers intestinal immunity
(John Wiley & Sons Ltd, 2022) Mabwi, Humphrey A.; Lee, Hee Ju; Hitayezu, Emmanuel; Mauliasari, Intan Rizki; Pan, Cheol-Ho; Mwaikono, Kilaza Samson; Komba, Erick V. G.; Lee, Choong-Gu; Hyun Cha, Kwang
BACKGROUND: The gut microbiota (GM) plays an important role in human health and is being investigated as a possible target for new therapies. Although there are many studies showing that emodin can improve host health, emodin–GM studies are scarce. Here, the effects of emodin on the GM were investigated in vitro and in vivo. RESULTS: In vitro single bacteria cultivation showed that emodin stimulated the growth of beneficial bacteria Akkermansia, Clostridium, Roseburia, and Ruminococcus but inhibited major gut enterotypes (Bacteroides and Prevotella). Microbial community analysis from a synthetic gut microbiome model through co-culture indicated the consistent GM change by emodin. Interestingly, emodin stimulated Clostridium and Ruminococcus (which are related to Roseburia and Faecalibacterium) in a mice experiment and induced anti-inflammatory immune cells, which may correlate with its impact on specific gut bacteria. CONCLUSION: Emodin (i) showed similar GM changes in monoculture, co-culture, and in an in vivo mice experiment and (ii) simulated regulatory T-cell immune responses in vivo. This suggest that emodin may be used to modulate the GM and improve health.
Evidence of carriage of antimicrobial resistant salmonella species of public health and veterinary significance in the intestines of house crows (corvus splendens) in Tanzania
(International Journal of TROPICAL DISEASE & Health, 2014) Katani, Shaaban J.; Komba, Erick V. G.; Mzula, Alexanda; Lyantagaye, Sylvester L.; Sosovele, Eva M.; Malebo, Hamisi M.
Background: The Indian house crow, Corvus splendens (Vieillot) was introduced in Zanzibar, Tanzania by the British and immigrants from India in 1897 to help clean the town. The crow is responsible for polluting the environment, water sources and human surroundings by their droppings and the rubbish they carry. This behavior has led to concern that, the crows may be responsible for the spread of certain pathogens including Salmonella and their persistence in the environment.Given the zoonotic potential of Salmonella, the main aim of this study was to investigate the occurrence of antimicrobial resistant Salmonella infections in Indian house crows and to determine if the isolates were similar to those associated with disease in livestock or humans. Methods: Indian house crows were lured with meat and blood baits to land into the crow live-trap set at the Mabibo compound of the National Institute for Medical Research (NIMR) in Dar es Salaam city in Tanzania. A total of 100 house crows were captured, humanely sacrificed, and their small and large intestines were obtained by using aseptic techniques for microbiological investigations. Culture technique was employed to detect the presence of Salmonella in intestinal contents; and preliminary identification of the isolates was based on colonial characteristics on selective media and microscopic examination of smears following Gram staining. Confirmation of Salmonella species was done by biochemical tests. Antimicrobial susceptibility testing was done by using the disc diffusion method on Mueller Hinton agar. Results and Discussion: Eight isolates were identified by standard microbiological techniques as Salmonella spp. (6 suggestive of Salmonella gallinarum and 2 suggestive of S. Typhi). All isolates were found to be susceptible to ciprofloxacin but resistant to amoxicillin. Lower levels of susceptibility were noted for chloramphenicol and ceftriaxone. Our results demonstrate the presence of antimicrobial resistant Salmonella spp. in the Indian house crows’ population and provide an indication of potential public and poultry health risks associated with these birds in the coastal area. Conclusion: The occurrence of antibiotic resistant S. Typhi and S. gallinarum among Indian house crows has both veterinary and public health consequences as they may be transmitted to poultry and humans. This therefore provides further rationale for the public action on eradicating the house crows.
Genomic characterization of fluoroquinolone-resistant thermophilic campylobacter strains isolated from layer chicken feces in gangneung, South Korea by whole-genome sequencing
(MDPI, 2021) Gahamanyi, Noel; Song, Dae-Geun; Yoon, Kye-Yoon; Mboera, Leonard E. G.; Matee, Mecky I.; Mutangana, Dieudonné; Komba, Erick V. G.; Pan, Cheol-Ho; Amachawadi, Raghavendra G.
Thermophilic Campylobacter species of poultry origin have been associated with up to 80% of human campylobacteriosis cases. Layer chickens have received less attention as possible reservoirs of Campylobacter species. Initially, the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of two archived Campylobacter isolates (Campylobacter jejuni strain 200605 and Campylobacter coli strain 200606) from layer chickens to five antimicrobials (ciprofloxacin, nalidixic acid, erythromycin, tetracycline, and gentamicin) were determined using broth microdilution while the presence of selected antimicrobial resistance genes was performed by polymerase chain reaction (PCR) using specific primers. Whole-genome sequencing (WGS) was performed by the Illumina HiSeq X platform. The analysis involved antimicrobial resistance genes, virulome, multilocus sequence typing (MLST), and phylogeny. Both isolates were phenotypically resistant to ciprofloxacin (MIC: 32 vs. 32 μg/mL), nalidixic acid (MIC: 128 vs. 64 μg/mL), and tetracycline (MIC: 64 vs. 64 μg/mL), but sensitive to erythromycin (MIC: 1 vs. 2 μg/mL) and gentamicin (MIC: 0.25 vs. 1 μg/mL) for C. jejuni strain 200605 and C. coli strain 200606, respectively. WGS confirmed C257T mutation in the gyrA gene and the presence of cmeABC complex conferring resistance to FQs in both strains. Both strains also exhibited tet(O) genes associated with tetracycline resistance. Various virulence genes associated with motility, chemotaxis, and capsule formation were found in both isolates. However, the analysis of virulence genes showed that C. jejuni strain 200605 is more virulent than C. coli strain 200606. The MLST showed that C. jejuni strain 200605 belongs to sequence type ST-5229 while C. coli strain 200606 belongs to ST-5935, and both STs are less common. The phylogenetic analysis clustered C. jejuni strain 200605 along with other strains reported in Korea (CP028933 from chicken and CP014344 from human) while C. coli strain 200606 formed a separate cluster with C. coli (CP007181) from turkey. The WGS confirmed FQ-resistance in both strains and showed potential virulence of both strains. Further studies are recommended to understand the reasons behind the regional distribution (Korea, China, and Vietnam) of such rare STs.
Leveraging sub-national collaboration and influence for improving animal health surveillance and response: a stakeholder mapping in Tanzania
(Frontiers in Veterinary Science, 2021-12-13) George, Janeth; Häsler, Barbara; Komba, Erick V. G.; Sindato, Calvin; Rweyemamu, Mark; Kimera, Sharadhuli I.; Mlangwa, James E. D.
Animal health surveillance plays a vital role in ensuring public health, animal welfare, and sustainable food production by monitoring disease trends, early detecting (new) hazards, facilitating disease control and infection, and providing data for risk analysis. Good stakeholder collaboration across the sector can lead to better communication, better science and decision-making and more effective surveillance and response. An understanding of relevant stakeholders, their interests and their power can facilitate such collaboration. While information on key stakeholders in animal health surveillance is available at the national level in Tanzania, it is missing at the subnational level. The study aimed to explore the existing stakeholders’ collaborations and influences at the subnational level through stakeholder mapping and to determine potential leverage points for improving the national animal health surveillance system. A qualitative design was used, involving consultative workshops with government animal health practitioners in Sumbawanga, Sikonge and Kilombero districts of Tanzania from December 2020 to January 2021. Data were collected using an adapted USAID stakeholder collaboration mapping tool with the following steps: (i) Define the objective (ii) Identify all stakeholders (iii) Take stock of the current relationships (iv) Determine resource-based influence (v) Determine non-resource based influence and (vi) Review and revise the collaboration map. Forty-five stakeholders were identified in all three districts and grouped into four categories: private sector and non-government organizations (n = 16), government (n = 16), community (n = 9) and political leaders (n = 4). Animal health practitioners had a stronger relationship with community stakeholders as compared to other categories. The results also showed that most of the stakeholders have non-resource-based influence compared to resource-based influence. The private sector and non-government organizations have a relatively higher number of resource-based influential stakeholders, while political leaders have more non-resource-based influence. The mapping exercise demonstrated that the system could benefit from community mobilization and sensitization, resource mobilization and expanding the horizon of surveillance data sources. Some of the leverage points include integration of surveillance activities into animal health services, clear operational processes, constant engagement, coordination and incentivization of stakeholders. The diversity in the identified stakeholders across the districts suggests that collaborations are contextual and socially constructed.
Mechanisms and contextual factors affecting the implementation of animal health surveillance in Tanzania: a process evaluation
(Frontiers in Veterinary Science, 2022-01-13) George, Janeth; Häsler, Barbara; Komba, Erick V. G.; Rweyemamu, Mark; Kimera, Sharadhuli I.; Mlangwa, James E. D.
A strong animal health surveillance system is an essential determinant of the health of animal and human population. To ensure its functionality and performance, it needs to be evaluated regularly. Therefore, a process evaluation was conducted in this study to assess animal health surveillance processes, mechanisms and the contextual factors which facilitate or hinder uptake, implementation and sustainability of the system in Tanzania. A mixed-method study design was used to evaluate the national animal health surveillance system guided by a framework for process evaluation of complex interventions developed by Moore and others. The system was assessed against standard guidelines and procedures using the following attributes: fidelity, adherence, exposure, satisfaction, participation rate, recruitment and context. Quantitative and qualitative data were collected using a cross-sectional survey, key informant interviews, document review, site visits and non-participant observation. Data from questionnaires were downloaded, cleaned and analyzed in Microsoft TM Excel. Qualitative data were analyzed following deductive thematic and content analysis methods. Fidelity attribute showed that case identification is mainly based on clinical signs due to limited laboratory services for confirmation. Data collection was not well-coordinated and there were multiple disparate reporting channels. Adherence in terms of the proportion of reports submitted per month was only 61% of the target. District-level animal health officials spent an average of 60% of their weekly time on surveillance-related activities, but only 12% of them were satisfied with the surveillance system. Their dissatisfaction was caused by large area coverage with little to no facilitation, poor communication, and lack of a supporting system. The cost of surveillance data was found to be 1.4 times higher than the annual surveillance budget. The timeliness of the system ranged between 0 and 153 days from the observation date (median = 2 days, mean = 6 days). The study pointed out some deviations in animal health surveillance processes from the standard guidelines and their implication on the system’s performance. The system could be improved by developing a user-friendly unified reporting system, the active involvement of subnational level animal health officials, optimization of data sources and an increase in the horizon of the financing mechanism.
Mechanisms and contextual factors affecting the implementation of animal health surveillance in Tanzania: a process evaluation
(Frontiers in Veterinary Science, 2022) George, Janeth; Häsler, Barbara; Komba, Erick V. G.; Rweyemamu, Mark; Kimera, Sharadhuli I.; Mlangwa, James E. D.
A strong animal health surveillance system is an essential determinant of the health of animal and human population. To ensure its functionality and performance, it needs to be evaluated regularly. Therefore, a process evaluation was conducted in this study to assess animal health surveillance processes, mechanisms and the contextual factors which facilitate or hinder uptake, implementation and sustainability of the system in Tanzania. A mixed-method study design was used to evaluate the national animal health surveillance system guided by a framework for process evaluation of complex interventions developed by Moore and others. The system was assessed against standard guidelines and procedures using the following attributes: fidelity, adherence, exposure, satisfaction, participation rate, recruitment and context. Quantitative and qualitative data were collected using a cross-sectional survey, key informant interviews, document review, site visits and non-participant observation. Data from questionnaires were downloaded, cleaned and analyzed in MicrosoftTM Excel. Qualitative data were analyzed following deductive thematic and content analysis methods. Fidelity attribute showed that case identification is mainly based on clinical signs due to limited laboratory services for confirmation. Data collection was not well-coordinated and there were multiple disparate reporting channels. Adherence in terms of the proportion of reports submitted per month was only 61% of the target. District-level animal health officials spent an average of 60% of their weekly time on surveillance-related activities, but only 12% of them were satisfied with the surveillance system. Their dissatisfaction was caused by large area coverage with little to no facilitation, poor communication, and lack of a supporting system. The cost of surveillance data was found to be 1.4 times higher than the annual surveillance budget. The timeliness of the system ranged between 0 and 153 days from the observation date (median = 2 days, mean = 6 days). The study pointed out some deviations in animal health surveillance processes from the standard guidelines and their implication on the system’s performance. The system could be improved by developing a user-friendly unified reporting system, the active involvement of subnational level animal health officials, optimization of data sources and an increase in the horizon of the financing mechanism.
Occurrence of Vibrio cholerae and Vibrio parahaemolyticus among milkfish farms in Zanzibar
(Taylor & Francis, 2019) Mnyoro, Mang’era Samwel; Komba, Erick V. G.; Mmochic, Aviti J.
ABSTRACT Fishing is among the main economic activities of the people of Zanzibar. Few fish dealers are transforming this sector into mariculture. Among the farmed fish is milkfish. Diseases are among the limiting factors in the development of the maricul- ture industry. Among other zoonotic diseases, vibriosis is caused by bacteria from the genus Vibrio. This study aimed to establish the occurrence of Vibrio cholerae and Vibrio para- haemolyticus among milkfish farms in Zanzibar. A total of 380 milkfish were sampled. Swabs were collected from gills, intes- tine, and kidney of each sampled milkfish. Preliminary identifi- cation of V. cholerae and V. parahaemolyticus was done by biochemical tests. PCR was run on 16S rRNA, outer membrane protein W, and collagenase genes to confirm Vibrio species, V. cholerae, and V. parahaemolyticus respectively. Almost one- third (32.1%) of all sampled milkfish were found to contain targeted Vibrio; 18% and 29.5% of the sampled milkfish were positive for V. cholerae and V. parahaemolyticus respectively.
Prevalence, risk factors, and antimicrobial resistance profiles of thermophilic campylobacter species in humans and animals in Sub-Saharan Africa: a systematic review
(International Journal of Microbiology, 2020) Gahamanyi, Noel; Mboera, Leonard E. G.; Matee, Mecky I.; Mutangana, Dieudonn´e; Komba, Erick V. G.
Termophilic Campylobacter species are clinically important aetiologies of gastroenteritis in humans throughout the world. -e colonization of different animal reservoirs by Campylobacter poses an important risk for humans through shedding of the pathogen in livestock waste and contamination of water sources, environment, and food. A review of published articles was conducted to obtain information on the prevalence and antimicrobial resistance (AMR) profiles of thermophilic Campylobacter species in humans and animals in sub-Saharan Africa (SSA). Electronic databases, namely, PubMed, Google Scholar, Resear- ch4life-HINARI Health, and Researchgate.net, were searched using the following search terms “thermophilic Campylobacter,” “Campylobacter jejuni,” “Campylobacter coli,” “diarrhea/diarrhoea,” “antimicrobial resistance,” “antibiotic resistance,” “humans,” “animals,” “Sub-Saharan Africa,” and “a specific country name.” Initially, a total of 614 articles were identified, and the lists of references were screened in which 22 more articles were identified. After screening, 33 articles on humans and 34 on animals and animal products were included in this review. In humans, Nigeria reported the highest prevalence (62.7%), followed by Malawi (21%) and South Africa (20.3%). For Campylobacter infections in under-five children, Kenya reported 16.4%, followed by Rwanda (15.5%) and Ethiopia (14.5%). -e country-level mean prevalence in all ages and under-five children was 18.6% and 9.4%, respectively. -e prevalence ranged from 1.7%–62.7% in humans and 1.2%–80% in animals. -e most reported species were C. jejuni and C. coli. -e AMR to commonly used antimicrobials ranged from 0–100% in both humans and animals. Poultry consumption and drinking surface water were the main risk factors for campylobacteriosis. -e present review provides evidence of thermophilic Campylobacter occurrence in humans and animals and high levels of AMR in SSA, emphasizing the need for strengthening both national and regional multisectoral antimicrobial resistance standard surveillance protocols to curb both the campylobacteriosis burden and increase of antimicrobial resistance in the region.
Susceptibility of campylobacter strains to selected natural products and frontline antibiotics
(MDPI, 2020) Gahamanyi, Noel; Song, Dae-Geun; Hyun Cha, Kwang; Yoon, Kye-Yoon; Leonard E.; Mboera, G.; Matee, Mecky I.; Mutangana, Dieudonné; Amachawadi, Raghavendra G.; Komba, Erick V. G.; Pan, Cheol-Ho
Campylobacter species have developed resistance to existing antibiotics. The development of alternative therapies is, therefore, a necessity. This study evaluates the susceptibility of Campylobacter strains to selected natural products (NPs) and frontline antibiotics. Two C. jejuni strains (ATCC® 33560TM and MT947450) and two C. coli strains (ATCC® 33559TM and MT947451) were used. The antimicrobial potential of the NPs, including plant extracts, essential oils, and pure phytochemicals, was evaluated by broth microdilution. The growth was measured by spectrophotometry and iodonitrotetrazolium chloride. Antibiotic resistance genes (tet(O) and gyrA) were characterized at the molecular level. The minimum inhibitory concentrations (MICs) and the minimum bactericidal concentrations (MBCs) ranged from 25 to 1600 μg/mL. Cinnamon oil, (E)-Cinnamaldehyde, clove oil, eugenol, and baicalein had the lowest MIC and MBC values (25–100 μg/mL). MT947450 and MT947451 were sensitive to erythromycin and gentamicin but resistant to quinolones and tetracycline. Mutations in gyrA and tet(O) genes from resistant strains were confirmed by sequencing. The findings show that NPs are effective against drug-sensitive and drug-resistant Campylobacter strains. The resistance to antibiotics was confirmed at phenotypic and genotypic levels. This merits further studies to decipher the action mechanisms and synergistic activities of NPs