Browsing by Author "Call, Douglas"

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Antimicrobial resistant enteric bacteria are widely distributed amongst people, animals and the environment in Tanzania
(Springer Nature Limited, 2020-01-13) Subbiah, Murugan; Caudell, Mark; Mair, Colette; Davis, Margaret; Matthews, Louise; Quinlan, Robert; Quinlan, Marsha; Lyimo, Beatus; Buza, Joram; Keyyu, Julius; Call, Douglas
Antibiotic use and bacterial transmission are responsible for the emergence, spread and persistence of antimicrobial-resistant (AR) bacteria, but their relative contribution likely differs across varying socio-economic, cultural, and ecological contexts. To better understand this interaction in a multi-cultural and resource-limited context, we examine the distribution of antimicrobial-resistant enteric bacteria from three ethnic groups in Tanzania. Household- level data (n = 425) was collected and bacteria isolated from people, livestock, dogs, wildlife and water sources (n = 62,376 isolates). The relative prevalence of different resistance phenotypes is similar across all sources. Multi-locus tandem repeat analysis (n = 719) and whole-genome sequencing (n = 816) of Escherichia coli demonstrate no evidence for host- population subdivision. Multivariate models show no evidence that veterinary antibiotic use increased the odds of detecting AR bacteria, whereas there is a strong association with livelihood factors related to bacterial transmission, demonstrating that to be effective, interventions need to accommodate different cultural practices and resource limitations.
Comparison of antibiotic resistant Escherichia coli obtained from drinking water sources in northern Tanzania: a cross-sectional study
(BMC Microbiology, 2016) Lyimo, Beatus; Buza, Joram; Subbiah, Murugan; Smith, Woutrina; Call, Douglas
Background: Antimicrobial resistance (AMR) is a growing and significant threat to public health on a global scale. Escherichia coli comprises Gram-negative, fecal-borne pathogenic and commensal bacteria that are frequently associated with antibiotic resistance. AMR E. coli can be ingested via food, water and direct contact with fecal contamination. Methods: We estimated the prevalence of AMR Escherichia coli from select drinking water sources in northern Tanzania. Water samples (n = 155) were collected and plated onto Hi-Crome E. coli and MacConkey agar. Presumptive E. coli were confirmed by using a uidA PCR assay. Antibiotic susceptibility breakpoint assays were used to determine the resistance patterns of each isolate for 10 antibiotics. Isolates were also characterized by select PCR genotyping and macro-restriction digest assays. Results: E. coli was isolated from 71 % of the water samples, and of the 1819 E. coli tested, 46.9 % were resistant to one or more antibiotics. Resistance to ampicillin, streptomycin, sulfamethoxazole, tetracycline, and trimethoprim was significantly higher (15–30 %) compared to other tested antibiotics (0–6 %; P < 0.05). Of the β-lactam-resistant isolates, blaTEM-1 was predominant (67 %) followed by blaCTX-M (17.7 %) and blaSHV-1 (6.0 %). Among the tetracyclineresistant isolates, tet(A) was predominant (57.4 %) followed by tet(B) (24.0 %). E. coli isolates obtained from these water sources were genetically diverse with few matching macro-restriction digest patterns. Conclusion: Water supplies in northern Tanzania may be a source of AMR E. coli for people and animals. Further studies are needed to identify the source of these contaminants and devise effective intervention strategies.
Comparison of the prevalence of antibiotic-resistant Escherichia coli isolates from commercial-layer and free-range chickens in Arusha district, Tanzania
(African Journal of Microbiology Research, 2016-09-14) Rugumisa, Bernadether; Call, Douglas; Mwanyika, Gaspary; Subbiah, Murugan; Buza, Joram
The antibiotic susceptibility of fecal Escherichia coli isolates from commercial-layer and free-range chickens in Arusha district, Tanzania were compared. All the chickens were raised by individual households, but commercial-layer chickens were purchased from commercial vendors, whereas no systematic breeding system was used to produce free-range chickens. A total of 1,800 E. coli isolates (1,200 from commercial-layer chickens and 600 from free-range chickens) were tested for susceptibility to 11 antibiotics by breakpoint assays. All E. coli isolates were susceptible to gentamicin, ceftazidime and cefotaxime. Isolates from commercial-layer chickens had a high prevalence of resistance (32.4- 74.5%) for amoxicillin, ampicillin, ciprofloxacin, tetracycline, streptomycin, trimethoprim and sulfamethoxazole, while the prevalence of resistance to these antibiotics was lower (7-31.5%) for freerange chickens (P<0.05). Both groups had a similar prevalence of resistance to chloramphenicol (1.17- 1.5%; P>0.05). For antibiotic resistant strains, 64.1 and 91.5% of free-range and commercial-layer isolates, respectively, were resistant to ≥ 2 antibiotics. Commercial-layer chickens harbored significantly more resistant E. coli isolates (P<0.001) than free-range chickens, consistent with more exposure to antibiotics when compared with free-range chickens. Efforts should be directed towards motivating household owners to limit the use of antibiotics when they are investing in these breeds.
Detection of microbial surface contamination and antibiotic resistant Escherichia coli on beef carcasses in Arusha, Tanzania
(African Journal of Microbiology Research, 2016-08-14) Murutu, Rehema; Luanda, Catherine; Rugumisa, Bernadetha; Mwanyika, Gaspar; Subbiah, Murugan; Call, Douglas; Buza, Joram
Food serves as an important fomite for transmission of disease-causing and antibiotic resistant bacteria to humans. Because this may be an especially challenging problem in low-income countries, the level of microbial surface contamination and abundance of antibiotic resistant Escherichia coli on beef carcasses were estimated. Out of 125 surface swab samples (plated on MacConkey agar), 70 to 100% were positive to Gram-negative bacteria and E. coli, respectively. More than 50% of individual carcasses had bacterial loads below the maximum threshold recommended by the FAO. For carcasses in small- and medium-scale facilities, the average load of bacteria ranged between 0.8 and 1.5 log cfu/cm2, while carcasses in the large slaughter facility had an average loads of between 1.77 and 1.42 log cfu/cm2. Of the 1,272 E. coli isolates tested, 49.4% were resistant to at least one antibiotic. Isolates were frequently resistant to tetracycline (21.7%) and ampicillin (19.2%) while the frequency of resistance to the remaining nine antibiotics was <3%. In addition, 5.3% of isolates were multidrug resistant with 18 different phenotypes. The combination of resistance to ampicillin and tetracycline was the most common. Although, poor sanitation practices were observed, results reflect lower bacterial counts and limited prevalence of antibiotic resistant E. coli relative to other reports in the literature.
IncF Plasmids Are Commonly Carried by Antibiotic Resistant Escherichia coli Isolated from Drinking Water Sources in Northern Tanzania
(Hindawi Publishing Corporation International Journal of Microbiology, 2016) Lyimo, Beatus; Buza, Joram; Subbiah, Murugan; Temba, Sylivester; Kipasika, Honest; Smith, Woutrina; Call, Douglas
The aim of this study was to identify the replicon types of plasmids, conjugation efficiencies, and the complement of antibiotic resistance genes for a panel of multidrug resistant E. coli isolates from surface waters in northern Tanzania. Standard membrane filtration was used to isolate and uidA PCR was used to confirm the identity of strains as E. coli. Antibiotic susceptibility was determined by breakpoint assay and plasmid conjugation was determined by filter-mating experiments. PCR and sequencing were used to identify resistance genes and PCR-based replicon typing was used to determine plasmid types. Filter mating experiments indicated conjugation efficiencies ranged from 10−1 to 10−7. Over 80% of the donor cells successfully passed their resistance traits and eleven different replicon types were detected (IncI1, FIC, P, FIIA,A/C, FIB, FIA,H12, K/B B/O, and N). IncF plasmids weremost commonly detected (49% of isolates), followed by types IncI1 and IncA/C. Detection of these public health-relevant conjugative plasmids and antibiotic resistant traits in Tanzanian water suggests the possible pollution of these water sources from human, livestock, and wild animal wastes and also shows the potential of these water sources in the maintenance and transmission of these resistance traits between environments, animals, and people.
Load and Prevalence of Antimicrobial-Resistant Escherichia coli from Fresh Goat Meat in Arusha, Tanzania
(Journal of Food Protection, 2016) Mwanyika, Gaspary; Call, Douglas; Rugumisa, Bernadether; Luanda, Catherine; Mrutu, Rehema; Subbiah, Murugan; Buza, Joram
Given the potential public health risks associated with a burgeoning goat meat industry in Tanzania, we estimated the load of Escherichia coli and the prevalence of antibiotic-resistant strains for goat meat by using a cross-sectional study design (June to July 2015). Five large (n¼60 samples) and five small (n¼64 samples) slaughterhouses were sampled over a period of four to six visits each. Meat rinsate was prepared and plated onto MacConkey agar, and presumptive E. coli colonies were enumerated and reported as CFU per milliliter of rinsate. In total, 2,736 presumptive E. coli isolates were tested for antibiotic drug sensitivity by using breakpoint assays against 11 medically important antibiotics. E. coli was recovered from almost all the samples (96.8%), with counts ranging from 2 to 4 log CFU ml 1, and there was no significant difference (P¼0.43) in recovery according to facility size (average, 3.37 versus 3.13 log CFU ml 1, large and small, respectively). Samples from large facilities had relatively higher prevalence (P ¼ 0.026) of antibiotic-resistant E. coli compared with small facilities. This was mostly explained by more ampicillin (30.1 versus 12.8%) and amoxicillin (17.6 versus 4.5%) resistance for large versus small facilities, respectively, and more tetracycline resistance for small facilities (5.6 versus 10.6%, respectively). Large slaughter operations may serve as foci for dissemination of antibiotic-resistant bacteria via food products. More effective hygiene practices during slaughter and meat handling would limit the probability of transmitting antibiotic-resistant E. coli in goat meat.
Narrative risk messages increase uptake and sharing of health interventions in a hard-to-reach population: A pilot study to promote milk safety among Maasai pastoralists in Tanzania
(Springer Open, 2019-04-30) Caudell, Mark; Charoonsophonsak, P. Victor; Miller, Annalise; Lyimo, Beatus; Subbiah, Murugan; Buza, Joram; Call, Douglas
Across pastoralist groups, dairy products often fulfill major nutritional, economic, and socio-cultural functions. These contributions are jeopardized by poor milk quality with studies among pastoralist groups showing dairy products can harbour a long list of pathogens. These potential risks underscore the need for more effective dairy hygiene interventions. Here, we determine how health messages advocating the “novel” method of pasteurization versus boiling, and administered in narrative versus technical formats, can have an impact on hygiene practices and milk quality in Maasai pastoralists. Four Maasai villages in northern Tanzania were purposively selected to receive intervention strategies that varied in message format (narrative or technical) and heat treatment advocated (boiling or pasteurization). Census lists were used to randomly select 30–35 households in each village (N = 125). Across three visits, milk hygiene knowledge and attitudes were monitored, hygiene practices were directly measured by smart thermometers that recorded heat treatment, and milk quality was determined by calculating total bacterial counts (TBCs) (N = 1007). Compared to initial levels, TBCs in the pasteurization-narrative village (N = 33) exhibited a 73.4% decrease (OR 0.148–0.480) after 7 days and a 59.1% decrease (OR 0.216–0.734) after 14 days. The boilingnarrative (N = 28) exhibited a significant decrease at 7 days (− 68.8%, OR 0.161–0.606), but this decrease was not significant after 14 days (− 35.5%, OR 0.322–1.253). There were no significant decreases for the pasteurizationtechnical (N = 29) or boiling-technical (N = 31) villages after 7 or 14 days. In addition, narrative health formats led to significantly greater retention of health messages and peer-to-peer sharing. Interventions to improve milk quality in pastoralist and other livestock-dependent communities may benefit from enabling the “novel” method of pasteurization. More broadly, our results suggest that the use of narrative messages can promote healthy behaviours when cultural norms are contrary to best health practices as well as enhance the sustainability and scalability of interventions targeted at hard-to-reach populations, including most pastoralist communities.
Prevalence of Antibiotic-Resistant Fecal Escherichia coli Isolates from Penned Broiler and Scavenging Local Chickens in Arusha, Tanzania
(Journal of Food Protection, 2016) Rugumisa, Bernadether; Call, Douglas; Mwanyika, Gaspary; Mrutu, Rehema; Luanda, Catherine; Lyimo, Beatus; Subbiah, Murugan; Buza, Joram
We compared the prevalence of antibiotic-resistant Escherichia coli isolates from household-level producers of broiler (commercial source breeds) and local chickens in the Arusha District of Tanzania. Households were composed of a single dwelling or residence with independent, penned broiler flocks. Free-range, scavenging chickens were mixed breed and loosely associated with individual households. A total of 1,800 E. coli isolates (1,200 from broiler and 600 from scavenging local chickens) from 75 chickens were tested for their susceptibility against 11 antibiotics by using breakpoint assays. Isolates from broiler chickens harbored a higher prevalence of antibiotic-resistant E. coli relative to scavenging local chickens, including sulfamethoxazole (80.3 versus 34%), followed by trimethoprim (69.3 versus 27.7%), tetracycline (56.8 versus 20%), streptomycin (52.7 versus 24.7%), amoxicillin (49.6 versus 17%), ampicillin (49.1 versus 16.8%), ciprofloxacin (21.9 versus 1.7%), and chloramphenicol (1.5 versus 1.2%). Except for resistance to chloramphenicol, scavenging local chickens harbored fewer resistant E. coli isolates (P , 0.05). Broiler chickens harbored more isolates that were resistant to 7 antibiotics (P , 0.05). The higher prevalence of antibiotic-resistant E. coli from broiler chickens correlated with the reported therapeutic and prophylactic use of antibiotics in this poultry population. We suggest that improved biosecurity measures and increased vaccination efforts would reduce reliance on antibiotics by these households.
Recovery and prevalence of antibiotic-resistant Salmonella from fresh goat meat in Arusha, Tanzania
(African Journal of Microbiology Research, 2016-08-28) Mwanyika, Gaspary; Buza, Joram; Rugumisa, Benardether; Luanda, Catherine; Murutu, Rehema; Lyimo, Beatus; Subbiah, Murugan; Call, Douglas
Meat products are clearly associated with foodborne pathogens including, antibiotic-resistant strains. Population growth and growing consumer demand facilitate the transmission of foodborne pathogens, particularly in developing countries. To determine the prevalence of antibiotic-resistant Salmonella in goat meat, a study was done in Tanzania (June to July, 2015). Overall 120 goat meat samples were collected from five large and five small slaughter facilities (n = 60, respectively). Pre-enrichment for Salmonella isolation was done in Tryptic Soy Broth followed by selective enrichment in Modified Semisolid Rappaport-Vassiliadis agar. Isolation of Salmonella was done in xylose-Lysine-Deoxycholate agar followed by biochemical confirmation in triple sugar iron agar. The average prevalence of Salmonella was 60 and 63% in large and small facilities, respectively. Breakpoint assays indicated an overall low prevalence of resistance (2 to 4%; n = 219 isolates) to ampicillin, amoxicillin, streptomycin, sulphamethoxazole and trimethoprim with complete susceptibility to ciprofloxacin, ceftazidime and cefotaxime. No significant difference (p > 0.05) in the prevalence of resistance between large and small facilities was observed. High probability of Salmonella contamination of goat meat from Arusha area of Tanzania can pose risks to consumers. Antibiotic resistance appears minimal in this population. Improved hygienic slaughter and meat-handling practices are encouraged to reduce the burden of Salmonella-positive meat products.
Surface waters in northern Tanzania harbor fecal coliform and antibiotic resistant Salmonella spp. capable of horizontal gene transfer
(African Journal of Microbiology Research, 2016-03-21) Lyimo, Beatus; Buza, Joram; Woutrina, Smith; Subbiah, Murugan; Call, Douglas
Some Salmonella spp. are important pathogenic bacteria that can be transmitted to people via food and water and that can cause disease characterized by mild to severe enteric and systemic illness. In developing countries, infections caused by pathogenic antibiotic resistant Salmonella spp. are a major health challenge, particularly in children. Through the use of membrane filtration and Environmental Protection Agency (EPA) 1200 methods, the presence of fecal coliforms and antibiotic resistant Salmonella spp. in surface water sources was investigated, some of which had shared access for animals and people. Out of 100 water samples, 76 were positive for fecal coliforms and 63% of the positive samples contained >100 CFU / 100 ml of water. We observed a significant positive correlation between the number of fecal coliforms and the presence of Salmonella spp. (r=0.46, n=100, P=0.01). Importantly, >26% of the samples were positive for Salmonella spp. and 88% of these samples harbored isolates resistant to ≥1 antibiotic. Moreover, we found that 26% of antibiotic resistant Salmonella spp. isolates were able to transfer their resistance traits to a recipient strain of Escherichia coli at the rate of 1-7 x 10-3 per donor cells. Microbiological contamination of water was clearly evident in open water sources from northern Tanzania, and the presence of Salmonella spp. poses an immediate risk to anyone who consumes these waters if untreated.
A systematic review of antibiotic-resistant Escherichia coli and Salmonella data obtained from Tanzanian healthcare settings (2004-2014)
(African Journal of Microbiology Research, 2017-01-14) Mwanyika, Gaspary O.; Subbiah, Murugan; Buza, Joram; Rugumisa, Bernadether; Call, Douglas
Antibiotic-resistant Escherichia coli and Salmonella are an increasing challenge to global health. In Tanzania reliable data is limited for trends of resistance in major hospital-acquired pathogens. Data on the prevalence of antibiotic-resistant E. coli and Salmonella from Tanzanian sources (2004-2014) was extracted from PubMed and Google Scholar databases (April -June, 2015). Descriptive statistics and logistic-regression analysis were used to estimate the prevalence and trends for resistant E. coli and Salmonella to selected antibiotics using R software. A total of 24 articles were availablefor review, of which 21/24 (87.5%) and 7/24 (29.2%) reported the prevalence of antibiotic-resistant E. coli and Salmonella, respectively. Across all studies the average prevalence of resistance to ampicillin and cotrimoxazole was higher for E. coli (81.6 and 77.7%, respectively) than for Salmonella (64.7and 59.3%, respectively). Both groups of pathogens were also resistant to ciprofloxacin (20-22%) and 3rd- generation cephalosporins (2.5-27.8%). A logistic-regression model for published data (2004-2014) indicated that during this period of time there has been a significant increase to amoxicillin/clavulanate, ceftazidime, ciprofloxacin and gentamicin in E. coli (P< 0.001), and a significant increase in resistance to ampicillin for Salmonella (P < 0.05).Decreased E. coli and Salmonella susceptibility to critical antibiotics threatens the effective treatment of these infections in Tanzania. Proactive strategies are needed to preserve these antibiotics that remain largely active against bacterial pathogens in Tanzania.