Takele Beyene

Veterinary Drug Residues in Food-animal Products: Its Risk Factors and Potential Effects on Public Health

The use of veterinary drugs in food-producing animals has the potential to generate residues in animal derived products (meat, milk, eggs and honey) and poses a health hazard to the consumer. There are many factors influencing the occurrence of residues in animal products such as drug’s properties and their pharmacokinetic characteristics, physicochemical or biological processes of animals and their products. The most likely reason for drug residues might be due to improper drug usage and failure to keep the withdrawal period. The major public health significances of drug residue are development of antimicrobial drug resistance, hypersensitivity reaction, carcinogenicity, mutagenicity, teratogenicity, and disruption of intestinal normal flora. The residual amount ingested is in small amounts and not necessarily toxic. However, there is limited information on the magnitude of veterinary drug residue worldwide. Hence, an extensive work has to be carried out to determine the magnitude of the problem, to prevent the occurrence of veterinary drug residues, and to familiarize all animal health professionals with the knowledge of pharmacokinetics, pharmacodynamics and toxicological effects of veterinary drugs to minimize the potential public health hazards due to drug residues in food of animal origin.

Identification and Antimicrobial Susceptibility Profile of Salmonella Isolated from Selected Dairy Farms, Abattoir and Humans at Asella Town, Ethiopia

Salmonella is one of the most common causes of food-borne diarrheal disease in human as well as animals. It is leading causes of acute gastroenteritis when ingested in contaminated foods, including meat and dairy products. Moreover, the emergence of multiple-resistant (MDR) isolates is increasing in human and veterinary medicines. Therefore, this cross-sectional study aims at isolation, identification and antibiogram of Salmonella from selected dairy cattle farms, abattoir and in contact humans in both dairy farms and abattoir of Asella, Ethiopia. We collected 185 samples from abattoir (n=94) and dairy farms (n=91), which were isolated and identified according to ISO-6579, 2002. The overall proportion of Salmonella was 6.5% (12/185) (dairy farms n=4, 4.4% and abattoir n=8, 8.5%). Antibiogram of isolated Salmonella was also evaluated against ten commonly used antibiotics in both humans and veterinary medicines to treat salmonellosis by using the Kibry Bauer disk diffusion method. All isolates (100%, n=12) were susceptible to ciprofloxacin and gentamycin followed by 91.7%, 75%, 66.7%, 58.3 and 50% of the isolates were susceptible to sulfamethoxazole-trimethoprim, chloramphenicol, kanamycin, nalidixic acid and streptomycin, respectively. However, cefoxitin showed the highest resistance (66.7%) followed by ampicillin and amoxicillin (58.3% each). Moreover, 50% of the isolates were resistant to two or more of the tested antimicrobial agents. The highest MDR was seen on polled hand swabs from abattoir, resistance to eight antimicrobials (80%, n=8/10) with the combination of cefoxitin, ampicillin, amoxicillin and streptomycin being more frequent. High proportion of Salmonella was isolated from abattoir sample than dairy farms. These isolate developed MDR to commonly prescribed antimicrobial agents in the study area. Hence, strict hygienic management in the farm and abattoir as well as rational use of antimicrobials should be practised to circumvent the further development of antimicrobial resistance.

Prevalence and antimicrobial susceptibility of Escherichia coli O157 in beef at butcher shops and restaurants in central Ethiopia

BackgroundEthiopia bears the largest burden of foodborne diseases in Africa, and diarrheal diseases are the second leading causes of premature deaths. Enterohemorrhagic Escherichia coli O157 causes an asymptomatic infection to severe diarrhea and/or hemolytic-uremic syndrome in humans.MethodsA total of 440 beef carcass and in-contact surface swabs from 55 butcher shops and 85 minced beef samples from 40 restaurants in central Ethiopia were collected and examined for the presence of E. coli O157. Standard microbiological methods were used to isolate and identify E. coli O157 and to characterize the antimicrobial resistance of the isolates.ResultsE. coli O157 was detected in 4.5% carcass swabs (n = 5) and 3.6% cutting board swabs (n = 4) samples from butcher shops. E. coli O157 was not detected in any of the minced beef samples obtained from restaurants. All isolates (n = 9) were 100% susceptible to five drugs, but five isolates were resistant to amoxicillin, two isolates to streptomycin and three isolates to chloramphenicol. One isolate was resistant to two drugs and another to three drugs.ConclusionsThe present study shows a low prevalence of E. coli O157 in beef sold at butcher shops. Nevertheless, given the low infective dose of this pathogen and the deep-rooted tradition of consuming raw or undercooked beef, the current prevalence should not be considered lightly from a public health perspective.

Prevalence of Escherichia coli O157:H7 in beef cattle at slaughter and beef carcasses at retail shops in Ethiopia.

BackgroundThere is paucity of information regarding the epidemiology of Escherichia coli O157: H7 in developing countries. In this study, we investigated the occurrence of E. coli O157: H7 associated with beef cattle at processing plants and at retail shops in Ethiopia.MethodsVarious samples were collected from beef cattle at slaughter/processing plants, carcass at retail shops and humans at health centers. E. coli O157: H7 was isolated, identified and characterized for antimicrobial resistance, using standard microbiological methods.ResultsAt the processing plants E. coli O157: H7 was detected in 1.89% of fecal, 0.81% of intestinal mucosal swab, 0.54% of skin swab and 0.54% of carcass internal swab samples. At retail shops it was detected in 0.8% of carcass and 0.8% of cutting board swab samples, while all samples from utensils, hands from workers, and fecal and stool samples were negative. All isolates were resistant to Amoxicillin, moderately resistant to Cefoxitine and Nitrofurantoins but susceptible to other antimicrobials tested.ConclusionsE. coli O157: H7 occurs at low prevalence in beef cattle, and the current sanitary dressing procedures in the processing plants and storage conditions in the retail shops are effective against E. coli O157: H7.

Determination of the sources and antimicrobial resistance patterns of Salmonella isolated from the poultry industry in Southern Ethiopia

BackgroundEthiopia set an ambitious masterplan to increase chicken meat and egg production from 2015 to 2020. Poultry breeding, multiplication and distribution centers in the country have received executive order to import, amplify and distribute commercial chickens to end users. The biosecurity and the pathogen fauna of the centers have not been evaluated as to whether the centers could implement the mission effectively without any risk. Thus, the aim of this study was to evaluate the biosecurity practices and the pathogen prevalence, risk factors and their antimicrobial resistance (AMR) using Salmonella as case study.MethodsRoutine farm workers of the centers were interviewed about the different management (biosecurity) practices using a checklist. Samples (n = 270) from different sources consisting of chicken’s cloacal swab (n = 244), personnel hand swab (n = 9) and bedding (n = 17) were collected from three chicken multiplication centers. Standard bacteriological methods were used for the isolation of Salmonella. Disk diffusion method was used for drug sensitivity testing.ResultsAntimicrobials were often over prescribed without confirming the cause of ill health and without susceptibility testing. The general biosecurity and flock management practices were substandard. Salmonella was isolated from 45 (16.7%) of the 270 samples. Its prevalence was significantly (p<0.05) associated with location of the multiplication center, 27% at Bonga and 10.6% at Hawassa. Sample type was also significantly (p<0.05) affected in that it was higher in the bedding (35.3%) and personnel hand swabs (33.3%) than in the chicken cloaca (14.8%), which demonstrates the poor biosecurity and personnel hygienic practices in the centers. All of the 45 isolates (100%) exhibited resistance to kanamycin and sulfamethoxazole-trimethoprim, nalidixic acid (97.8%), ampicillin (97.8%), cefoxitin (97.8%), streptomycin (97.8%) tetracycline (97.8%), chloramphenicol (91.3%), ciprofloxacin (31.1%), and gentamicin (0%). Alarmingly, 42 isolates (93.4%) exhibited multidrug resistance (MDR) to ≥ 8 drugs and all 45 isolates had resistance to ≥ 3 drugs. The high rate of Salmonella isolation from (i) bedding, (ii) personnel hand swabs (iii) chickens, (iv) presence of more MDR isolates, (v) coupled with poor biosecurity practices in the centers could pose a risk for spreading of pathogens and drug resistant genes to the smallholder chicken producers and the public.ConclusionsWe conclude that the poultry breeding, multiplication and distribution centers in Ethiopia, as they stand currently, seem to be a source of pathogens and AMR isolates at least for Salmonella. Therefore, strict biosecurity, personnel safety, prudent drug use, regular monitoring and traceability of Salmonella serotypes or genotypes and AMR are recommended.

Assessment on Chemicals and Drugs Residue in Dairy and Poultry Products in Bishoftu and Modjo, Central Ethiopia

Despite the growing of contamination of foods of animal origin with chemicals during production, processing and storage, less attention being paid for the potentially present chemical residues in such foods (meat, milk, eggs and their products). This study was carried out to assess the chemicals and veterinary drugs used, and their possible occurrence as residue in dairy and poultry products in randomly selected dairy and poultry farms, and milk and animal feed processing plants located in Bishoftu and Modjo, central Ethiopia through questionnaire and observation. The result of this study showed that antibiotics, mainly penicillin-streptomycin and ampicillin-cloxacilin combination were used in all dairy farms while oxytetracycline and sulfa drugs were used by 85.7% and 57.1% of dairy farms. Oxytetracycline, amoxicillin, ciprofloxacillin, and sulfa drugs were used in 100%, 71.4%, 28.6%, and 28.6% of poultry farms, respectively. The study also revealed albendazole and ivermectin were commonly used in 96.4% and 71.4% of the dairy farms, respectively while piperazine was a common anthelmintic used in 31.0% of poultry farms. The antiprotozoal drugs commonly used in poultry farm were amprolium (100%) and sulfa drugs (26.3%) while the commonly used drug in dairy farms was sulfa drugs (50.0%). Antiseptics, namely, savlon (82.2%), iodine tincture (53.3%) and denatured alcohol (53.3%) were commonly used in dairy farm whereas disinfectants, such as, hydrogen peroxide (83.3%), sodium hydroxide (66.7%), and formalin (19.0%) were commonly used in poultry farms though small number of dairy farms also used formalin (17.8%) and hydrogen peroxide (10.7%). Among the rodenticides used in farms, zinc phosphide was used more in poultry farms (33.3%) than dairy farms (14.3%). Different chemicals were also used in the milk and feed processing plants. We conclude that there are high possibility of drug and chemical residues occurrence in poultry and dairy products in the area.

Assessment of Plant and Chemical Poisoning In Livestock in Central Ethiopia

The survey was conducted with the objective of assessing potentially poisonous plants and chemicals in and around Adama town, Central Ethiopia. Three types of structured questionnaires were developed and 118 individuals (93 livestock owners, 11 animal health practitioners and 14 factories managers) were interviewed on voluntary basis. The result of this assessment indicated that 71(76.3%) of livestock owners and 10(90.9%) of animal health practitioner complained presence of plant poisoning on livestock in the study area. Similarly 31 plants were identified as having poisoning effect on livestock among which Rhizophoraceae, Sorghum bicolar, Parthenium hysterophorus, and Medicago polymorpha had the highest botanical frequency. On the other hand, 22(23.7%) livestock owners and 1(9.1%) animal health practitioners observed chemical toxicosis, respectively. About two individuals of (14.2%) interviewed factories managers received complaints of chemical toxicosis of livestock due to inappropriate disposal of their wastes. Food shortage 48%, nutritional deficiency 10.4% and due to excess consumption 8.1% were identified as major risk factors which predispose livestock in and around Adama town to poisonous plants and toxic chemicals. Therefore, further study on complained poisonous plants and toxic chemicals in the study area, and institution of pertaining control and prevention method is strongly recommended.

New Targets in Malaria Parasite Chemotherapy: A Review

Malaria is a global health problem that causes significant mortality and morbidity annually and a serious problem to drug therapy and discovery as current anti-malarial therapeutics become increasingly ineffective. The need for new therapy for malaria is mandatory because of the emergence of resistance to most of the anti-malarial drugs. There are different approaches and targets proposed by researchers and scientist based on experimental data. Modern advancement in the biology of the parasite and different genomic techniques provide wide ranges of novel targets in the development of new therapy. Therefore, this review will discuss new targets in the chemotherapy of malaria parasite.

Staphylococcus: Isolation, Identification and Antimicrobial Resistancein Dairy Cattle Farms, Municipal Abattoir and Personnel in and AroundAsella, Ethiopia

A cross sectional study was conducted between February, 2014 and April, 2014 to isolate and identify Staphylococcus from dairy cattle farms and municipal abattoir; and to evaluate antimicrobial sensitivity for isolates in and around Asella, Ethiopia. An over all of 181 samples were collected and processed from nine dairy cattle farms (87) and seven municipal abattoir visits (94). Accordingly, 42 (23.2%) udder milk, 9 (5.0%) tank milk, 9 (5.0%) polled bucket swab, 9 (5.0%) tank swab, 9 (5.0%) polled hand swab, 9 (5.0%) polled nasal swab, from dairy cattle farms; and 66 (36.5%) meat swab, 7 (3.9%) polled knife swab, 7 (3.9%) polled slaughter line swab, 7 (3.9%) polled hand swab and 7 (3.9%) polled nasal swab from municipal abattoir visits were collected. The result showed the overall proportion of Staphylococcus was 89 (49.2%). Staphylococcal species were more predominant in abattoir 50/94 (53.2%) than farms 39/87 (44.8%), but there was no significant difference between them because p>0.05 at 95% confidence interval. Also high proportion of Staphylococcus was isolated from polled farm nasal swab 8/9 (88.9%), but this difference between sample type and the presence of Staphylococcus is not significant, because p-value (0.303) is greater than 0.05 at 0.05 level. Up on isolation and identification 35 (19.3%), 6 (3.3%), 24 (13.3%), 24 (13.3%) were S. aureus, S. intermedius, S. hyicus and Coagulase Negative Staphylococci (CNS), respectively. From total positive samples, 55 isolates were tested for antimicrobial susceptibility to different 15 antimicrobial discs. The comparative efficacies of antimicrobials used indicates Gentamycin, Kanamycin, Chloramphenicol, Ciprofloxacillin, and Sulphamethoxazole trimethoprim, were the most effective antibiotics where by 94.5%, 89.1%, 81.8%, 81.8%, and 81.8% respectively. Good hygienic practices should be followed both in dairy cattle farms and municipal abattoir including working personnel and equipment’s used; and antimicrobials susceptibility test should be carried out at regular intervals to find out the development of resistance against the most commonly applied antibiotics.

Assessment of Rational Veterinary Drugs Use in Livestock at Adama District Veterinary Clinic, Central Ethiopia

A retrospective study was conducted to evaluate rational drug use in livestock at Adama district veterinary clinic, central Ethiopia. 2,000 animal patients’ encounters were randomly selected for the study from prescription registration books retrospectively. A total of 2,489 drug products prescribed for a total of 2,000 patients were assessed. The average number of drugs prescribed per encounter was 1.25 with maximum of three. The percentages of encounters in which antimicrobials (AM) and anthelmintics (AH) were prescribed were 46.4% (1,156/2,489) and 46.7% (1,163/2,489), respectively. The percentages of drugs prescribed by generic name and from national veterinary drug list were 97.4% (2,424/2,489) and 100%, respectively. The most commonly prescribed AM and AH were oxytetracycline 73.9% (854), penicillin and streptomycin fixed combination 22.6% (261) and ivermectin 94.8% (1,102), respectively. Among the total of 2,000 animal patient encounters, all (100%) were treated empirically without getting correct laboratory supported diagnosis. Evaluation of drug prescription pattern based on clinical symptoms or disease diagnosed revealed that AM (22.6%) and AH (36.7%) were mostly prescribed for respiratory and musculoskeletal-integumentary systems, and gastrointestinal related clinical symptoms, respectively. The study result also showed AM (6.5%) were prescribed for parasitic diseases whereas AH were administered for bacterial (2.9%) and surgical (0.9%) cases respectively. Among 2489 drugs prescribed by professionals, 1762 (88.1%) and 238 (11.9%) were done by animal health assistants and veterinarians, respectively. On the basis of the finding of this study, the prescribing practice for antimicrobials shows deviation from the standard recommended by WHO. The findings had shown problems in generic prescribing, incorrect diagnosis and standardized patient case book with low prescribers’ educational status in the study area. Therefore, veterinary drugs should be judiciously used; and a wide scale study to safeguard the public from drug residual effects and antimicrobial resistance development is recommended.