Fenotipska obilježja virulencije, enteropatogeni serovarovi i tvorba verotoksina sojeva bakterije E. coli izdvojenih iz pasa na Trinidadu u kojih nije ustanovljen proljev

The study was conducted to determine the prevalence and selected characteristics of Escherichia coli in non-diarrhoeic dogs from Trinidad. Rectal swabs or faecal samples were collected. Primary isolation of E. coli was done on eosin methylene blue (EMB) agar, haemolysin and mucoid production were detected on blood agar (BA) and sorbitol fermentation was assayed on sorbitol MacConkey agar (SMAC) agar. Agglutination tests, using commercially available antisera, determined O157-positive and enteropathogenic (EPEC) strains of E. coli while the vero cell assay detected verocytotoxigenic E. coli (VTEC) strains. Overall, of a total of 1,391 dogs sampled, E. coli was isolated from 1,266 (91.0%) dogs. Differences were statistically significant amongst E. coli isolated from dog sources (P<0.05; χ2) with the highest (96.0%) and lowest (81.3%) prevalence detected in hunting dogs and pound dogs, respectively. Of the 1,900 E. coli isolates tested, 100 (5.3%), 81 (4.3%) and 133 (7.0%) were mucoid, haemolytic and non-sorbitol fermenting (NSF) respectively. The difference was statistically significant (P<0.05; χ2). For EPEC strains, of the 333 E. coli isolates tested, 189 (56.8%) belonged to ‘enteropathogenic’ serogroups. The difference in prevalence across the various dog sources was statistically significant (P<0.05; χ2). Of the 558 E. coli strains tested, 74 (13.3%) were positive for verocytotoxin production. It was concluded that asymptomatic dogs in Trinidad carry virulent strains of E. coli, posing a threat as reservoirs of infections to human handlers and their owners and therefore are of significance for public health.Istraživanje je poduzeto radi određivanja prevalencije i određenih značajki bakterije Escherichia coli u pasa bez proljeva na Trinidadu. Pretraženi su bili uzorci obrisaka rektuma i izmeta. E. coli bila je izdvojena na eozinmetilensko plavilo agaru. Tvorba hemolizina i sluzi dokazivana je na krvnomu agaru, a fermentacija sorbitola na MacConkey sorbitolskom agaru. Serološka skupina O157 i enteropatogenost dokazani su aglutinacijskim testom pomoću komercijalnih antiseruma, dok su verocitotoksigeni sojevi dokazani testom na staničnoj kulturi VERO. E. coli bila je izdvojena iz 1266 (91,0%) od pretraženih 1391 psa. Statistički značajne razlike ustanovljene su u izdvajanju E. coli (P<0,05; χ2) s najvećom prevalencijom (96,0%) u lovačkih pasa i najmanjom (81,3%) u tornjaka. Od analiziranih 1900 izolata E. coli, 100 (5,3%) je imalo sluzave kolonije, 81 (4,3%) je bio hemolitičan, a 133 (7,0%) izolata nisu fermentirala sorbitol. Razlika je bila statistički značajna (P<0,05; χ2). Od 333 pretražena izolata, 189 (56,8%) ih je pripadalo enteropatogenim (EPEC) serološkim skupinama. Razlika je bila statistički značajna s obzirom na različito podrijetlo pretraženih pasa (P<0,05; χ2). Od pretraženih 558 izolata E. coli, 74 (13,3%) tvorila su verocitotoksin. Može se zaključiti da psi na Trinidadu u kojih nije ustanovljen proljev mogu biti nositelji patogenih sojeve E. coli što predstavlja prijetnju za njihove vlasnike, a taj je nalaz od javnozdravstvenog značenja

Učestalost otpornosti na antimikrobne lijekove izolata bakterije E. coli izdvojenih na farmama mliječnih krava u Trinidadu promatrana na osnovi podrijetla izolata i prisutnosti čimbenika virulencije

A cross-sectional study was conducted on 50 dairy farms in Trinidad. Faecal samples were collected from cows, calves and humans; rectal swabs from pet dogs as well as bulk milk and milking parlour effluent. The disc diffusion method was used to detect resistance to eight antimicrobial agents amongst 500 isolates of Escherichia coli. The vero cell assay was used for verocytotoxin (VT) and heat-labile (LT) detection while the polymerase chain reaction (PCR) was used to detect VT genes amongst selected isolates. In Waller Field, 70.0% (168 of 240) of the E. coli isolates exhibited resistance to one or more antimicrobial agents compared with 83.5% (217 of 260) of the isolates from Carlsen Field (P <0.001; χ2). Overall, the frequency of resistance of isolates was highest to streptomycin (72.7%) and lowest to the fluoroquinolones (0.2%). Of a total of 130 E. coli isolates positive for O157 strain, VT gene, VT and or LT production, 104 (80.0%) were resistant. Resistance amongst E. coli strains with virulence markers could pose therapeutic problems on dairy farms in Trinidad.Presječno istraživanje provedeno je na 50 farmi mliječnih krava u Trinidadu. Uzorci izmetina krava, teladi i ljudi, te rektalni obrisci pasa bili su pretraženi na prisutnost bakterije E. coli. Pretraženi su bili i skupni uzorci mlijeka iz spremnika za mlijeko te uzorci iz mljekovoda. Za određivanje otpornosti na osam različitih antimikrobnih tvari difuzijskim je postupkom bilo pretraženo 500 izolata. Za dokazivanje tvorbe verotoksina i određivanje termolabilnosti rabljena je VERO stanična kultura, dok su odabrani izolati bili pretraženi lančanom reakcijom polimerazom za dokazivanje gena za verotoksin. Na području Waller je 70,0% (168 of 240) izolata E. coli bilo otporno na jedno ili više antimikrobnih tvari, a na području Carlsen 83,5% (217 of 260) (P<0.001; χ2). Učestalost otpornosti izolata bila je najveća prema streptomicinu (72,7%), a najmanja prema fluorokinolonima (0,2%). Od 130 pretraženih izolata serološke skupine O157, koji su sadržavali gen za verotoksin, proizvodili verotoksin ili termolabilni toksin otporna su bila 104 (80,0%) izolata. Otpornost izolata bakterije E. coli koji su posjedovali markere virulencije mogla bi predstavljati problem u liječenju na farmama mliječnih krava na Trinidadu

Experimental Study on Brucella abortus Strain RB51 Vaccinated Water Buffalo (Bubalus bubalis) Challenged with Virulent B. abortus Strain during Pregnancy

The study was conducted to determine the efficacy of Brucella abortus strain RB51 (RB51) vaccine in preventing abortion in pregnant water buffalo (Bubalus bubalis) experimentally challenged using the intravenous route, with a local pathogenic strain of B. abortus biovar 1 (Trinidad 1). Thirty-two female water buffalo calves aged 6-10 months were randomly divided into three groups for the vaccination trial using the subcutaneous route: Group I animals received recommended dose (RD) vaccine twice 4 weeks apart, Group II was vaccinated twice 18 weeks apart and Group III (control) received saline once. At approximately 6 months of pregnancy following natural breeding, the animals were challenged by the intravenous route with 2.5 x 108 to 4.4 x 108 colony forming units of a local strain of B. abortus, Trinidad 1. Blood samples were collected, pre-challenge and post-challenge, for serological assay using the BPAT and the animals were monitored for clinical signs. The bacteriological study was also performed on tissues of the dams and their calves. The frequency of abortion/stillbirths/early neonatal deaths was 55.6% (5/9), 42.9% (3/7) and 40.0% (2/5) for Groups I, II and III dams respectively (P&gt;0.05; ?2). For calves from infected dams, the frequency of isolation of B. abortus Trinidad 1 from the abomasal and rectal swabs was 100.0%, 80.0% and 100.0% for Groups I, II and III animals respectively (P&gt;0.05). It was concluded that vaccination of water buffalo with the RB51 vaccine using the recommended dose was ineffective in preventing infection, abortion, stillbirths, and neonatal deaths

Brucellosis in domestic water bufallo (Bubalus bubalis) of Trinidad and Tobago with comparative epidemiology to cattle

The water buffalo is an important domestic animal worldwide and the local Buffalypso variety was developed in Trinidad to have improved beef qualities. Brucellosis was diagnosed in Trinidad and Tobago during 1998 in both cattle and domestic water buffalo (Bubalus bubalis) populations. Brucellosis in the latter species is caused by infection with Brucella abortus, similar to bovine brucellosis. Control of brucellosis is of paramount importance to preservation of the genetic diversity of these animals in Trinidad, and this has been complicated by differences in the epidemiology of water buffalo and bovine brucellosis. Some diagnostic tests do not have comparable accuracy between the two species, and the RB51 vaccine does not adequately protect against infection in water buffalo. The water buffalo in Trinidad may also be more resistant to infection than cattle. Development of effective vaccination protocols is key to control disease in Buffalypso in Trinidad, and prohibitions on import of virulent B. abortus strains for vaccine efficacy studies has impeded progress in this area. These Trinidadian strains are of variable virulence; some might be effective for challenge in vaccine efficacy studies, while other, of lower virulence, may be vaccine candidates for use in water buffalo.The Campus Research Funds Committee, St. Augustine.http://www.springerlink.com/content/0049-4747ab201

Antimicrobial resistance profiles of salmonella isolates on chickens processed and retailed at outlets of the informal market in Gauteng Province, South Africa

The study determined the antimicrobial resistance profiles of Salmonella on chickens processed and retailed at outlets of the informal markets in Gauteng province, South Africa. The study also investigated the relationship of antimicrobial resistant Salmonella to the source and type of samples and their serotypes. Carcass swabs, cloacal swabs and carcass drips were randomly collected from each of 151 slaughtered chickens from six townships. Isolation and identification were performed using standard and polymerase chain reaction (PCR) methods. The disc diffusion method was used to determine the resistance of Salmonella isolates to 16 antimicrobial agents and PCR to determine their serovars. Ninety-eight (64.9%) of the 151 chickens were contaminated with Salmonella of which 94.9% (93/98) were resistant serovars. The frequency of antimicrobial resistance of Salmonella isolates was high to erythromycin (94.9%) and spectinomycin (82.7%) but was low to ciprofloxacin (1.0%) and norfloxacin (1.0%) (p < 0.05). All 170 isolates of Salmonella tested exhibited resistance to one or more antimicrobial agents and the frequency varied significantly (p < 0.05) across the townships, the type of samples and the serovars. The prevalence of multidrug resistance (MDR) in Salmonella was 81.8% (139/170). Our findings pose zoonotic, food safety and therapeutic risks to workers and consumers of undercooked, contaminated chickens from these outlets.http://www.mdpi.com/journal/pathogenspm2022Paraclinical SciencesProduction Animal StudiesVeterinary Tropical Disease

Prevalence and characterization of Campylobacter species from chickens sold at informal chicken markets in Gauteng, South Africa

This study determined the prevalence, characteristics, and risk factors of Campylobacter species contamination of chicken carcasses sold at informal poultry outlets in Gauteng province, South Africa. Within six townships, 151 chicken carcasses were collected from 47 outlets. Carcass swab, cloacal swab, and carcass drip samples were collected from each chicken, along with a matched questionnaire on risk factors regarding Campylobacter contamination. Sample-inoculated Bolton broth (BB) was cultured to isolate Campylobacter species by bacteriological methods. Subsequent confirmation and characterization of Campylobacter were conducted using polymerase chain reaction (PCR). Isolated Campylobacter strains were evaluated for the presence of six virulence genes (ciaB, dnaj, pldA, racR, flaA, and flaB), three toxin genes (cdtA, cdtB, and cdtC), and one antimicrobial resistance gene (tetO). The overall prevalence of Campylobacter was 23.4% (106 of 453), with sample type–specific prevalence being 17.2% (26 of 151), 25.8% (39 of 151), and 27.2% (41 of 151) for the carcass swabs, cloacal swabs, and carcass drip, respectively, following bacteriological isolation and confirmation by PCR. The overall prevalence of Campylobacter species was 93.5% by PCR, which varied significantly (P = 0.000) by sample: 99.2, 98.4, and 82.8% for carcass swabs, cloacal swabs, and carcass drip, respectively, by using PCR to detect Campylobacter in BB. Important risk factors for carcass contamination by Campylobacter included the slaughter of culled breeders and spent chickens, the use of stagnant water, and poor sanitation. Virulence and toxin gene frequencies were higher in C. jejuni–positive (82.5%) than in C. coli–positive (71.4%) BB cultures, but tetracycline resistance gene (tetO) frequency was higher in C. coli (75.9%) than in C. jejuni (48.10%). The observed high frequencies in C. jejuni recovered from street-vended chickens may pose food safety and therapeutic concerns to consumers.The Department of Agriculture and Research Council, the Agriculture Sector Education Training Authority, and the National Research Foundation.https://www.sciencedirect.com/journal/journal-of-food-protectionhj2023Production Animal StudiesVeterinary Tropical Disease

Molecular and phenotypic characterization of Staphylococcus aureus strains isolated from carcass swabs and carcass drips of chickens slaughtered in the informal market in Gauteng Province, South Africa

The study was conducted to characterize Staphylococcus aureus strains from swabs and drips of dressed chicken carcasses sold at outlets in six townships in the informal market in Gauteng province, South Africa, using molecular and phenotypic methods. Seven genes (6 toxins and 1 antimicrobial resistance) comprising staphylococcal enterotoxin A (SEA), B (SEB), C (SEC), D (SED), exfoliative toxin A, toxic shock syndrome toxin, and MecA encoding methicillin resistance were assayed using polymerase chain reaction. The resistance of the S. aureus strains to 18 antimicrobial agents was determined using the disk diffusion method. The frequency of detection of the six toxin genes was sea (52.2%), followed by seb (10.9%), sec (6.5%), sed (2.2%), eta (93.5%), and tst (19.6%). The mecA gene was detected in 4.3% of the isolates. The predominant profiles of toxin genes detected were sea‐eta (37.0%). All 63 isolates of S. aureus were resistant to one or more antimicrobial agents. The frequency of resistance was high to spectinomycin (98.4%), nalidixic acid (85.7%), and penicillin (84.1%), but low to gentamycin (1.6%) and cefotaxime (1.6%). The high frequency of toxin genes and antimicrobial resistance gene observed in S. aureus isolates from chicken could pose a challenge to food safety and may have therapeutic and zoonotic implications.Appendix 1: (Supplementary data) Frequency of resistance to antimicrobial agents by S. aureus strains from carcass swabs and dripsGauteng Department of Agriculture and Rural Developmenthttp://wileyonlinelibrary.com/journal/jfs2021-04-22hj2020Production Animal StudiesVeterinary Tropical Disease

Multiple-locus variable-number tandem repeat analysis genotypes of Listeria monocytogenes isolated from farms, abattoirs, and retail in Gauteng Province, South Africa

The use of multiple-locus variable-number analysis (MLVA) of tandem repeats (TRs) for subtyping Listeria monocytogenes has proven to be reliable and fast. This study determined the MLVA genotypes of 60 isolates of L. monocytogenes recovered from cattle farms, abattoirs, and retail outlets in Gauteng province, South Africa. The distribution of the 60 L. monocytogenes isolates analyzed by type of sample was as follows: raw beef (28, 46.7%), ready-to-eat beef products (9, 15.0%), beef carcass swabs (9, 15.0%), cattle environment (6, 10.0%), and cattle feces (8, 13.3%). The serogroups of the isolates were determined using PCR and the MLVA genotypes based on six selected loci. The frequency of the 60 serogroups detected was as follows: 1/2a-3a (IIa) (27, 45.0%); 4b-4d-4e (1Vb) (24, 40.0%); 1/2c-3c (IIc) (8, 13.3%); and 1/2b-3b (IIb) (1, 1.7%). MLVA successfully clustered genetically related isolates and differentiated nonrelated isolates, irrespective of their sources, sample types, and serogroups, as demonstrated by 16 MLVA pattern types detected. For serogroup 4b-4d-4e (IVb), there was no variation in TRs LM-TR2, LM-TR4, and LM-TR6, which each contained only one allele (02, 00, and 93, respectively). However, across the sources and sample types of isolates, there was variation in serogroup 4b-4d-4e (IVb): LM-TR1 contained 00, 03, and 05; LM-TR3 contained 14, 20, and 22; and LM-TR5 contained 14, 21, and 25. Similar patterns of variation in the TRs were detected in the other serogroups (1/2a-3a, 1/2b-3b, and 1/2c-3c). BioNumeric data analysis identified at least five types in Gauteng province. MLVA epidemiologically clustered the related isolates and differentiated unrelated isolates.Red Meat Research and Development, South Africa (RMRD-SA).https://www.sciencedirect.com/journal/journal-of-food-protectionProduction Animal Studie

Prevalence and risk of staphylococcal and coliform carcass contamination of chickens slaughtered in the informal market in Gauteng, South Africa

PURPOSE : The primary objective was to determine the prevalence of indicator microorganisms [Staphylococcus aureus, non-S. aureus staphylococci (NSAS), coliforms and aerobic bacteria] for contamination of chicken carcasses, carcass drip and rinse water from the informal chicken market in Gauteng, South Africa. DESIGN/METHODOLOGY/APPROACH : Chicken swabs, chicken drips and rinse waters were collected from 151 chickens from 47 random outlets. Pre-tested questionnaires were administered to capture the risk factors for bacterial contamination. Standard microbiological procedures were conducted for isolation and enumeration of target bacteria. FINDINGS : NSAS (64% and 41%) and S. aureus (12% and 31%) were prevalent on carcasses and in carcass drip respectively. Coliforms (62%) and aerobic bacteria (85%) were detected in rinse water. Significant risk factors for contamination of carcasses with NSAS, S. aureus and coliform organisms were: evisceration of chickens on the same location used for sale, cleaning of display counter with dirty clothes/wipes, holding of differently sourced chickens in the same cage prior to slaughter, not cleaning the display table/counter and hands at all, washing knives in rinse water, high turnover of daily slaughter and length of time to display chickens. RESEARCH LIMITATIONS/IMPLICATIONS : The limitations of this research were the limited geographical coverage and small sample size. PRACTICAL IMPLICATIONS : The isolation of these indicator microorganisms suggests the potential presence of other chicken-borne pathogens not tested for in the study. SOCIAL IMPLICATIONS : The findings serve to inform policy on public health and street-vended food and can guide control on good sanitary practices. ORIGINALITY/VALUE : This is the first comprehensive report on ready to eat chickens from the informal markets in Gauteng, South Africa.The Gauteng Department of Agricultural and Rural Development (GDARD)https://www.emerald.com/insight/publication/issn/0007-070Xhj2021Production Animal StudiesVeterinary Tropical Disease

Occurrence, risk factors, serotypes, and antimicrobial resistance of Salmonella strains isolated from imported fertile hatching eggs, hatcheries, and broiler farms in Trinidad and Tobago

SUPPLEMENTARY MATERIAL 1 : Hatchery questionnaire.SUPPLEMENTARY MATERIAL 2 : Broiler farm questionnaire.This cross-sectional study was conducted to determine the occurrence, risk factors, and characteristics of Salmonella isolates recovered from imported fertile broiler hatching eggs, hatcheries, and broiler farms in Trinidad and Tobago. Standard methods were used to isolate and characterize Salmonella isolates from two broiler hatcheries and 27 broiler farms in the country. The frequency of isolation of Salmonella was 0.0% for imported fertile hatching eggs (0 of 45 pools of 10 eggs each, i.e., 450 eggs), 7.6% for hatcheries (12 of 158 samples), and 2.8% for broiler farms (24 of 866 samples) (P = 0.006). Stillborn chicks at hatcheries had the highest prevalence of Salmonella (7 of 28 samples, 28.0%), whereas on broiler farms the cloacal swabs had the highest prevalence of Salmonella (15 of 675 samples, 2.2%). None of the 15 farm management and production practices investigated were significantly associated (P > 0.05) with the isolation of Salmonella. The predominant Salmonella serotypes were Kentucky (83.3%) and Infantis (62.5%) among hatchery and farm isolates, respectively. The disk diffusion method revealed frequencies of antimicrobial resistance (i.e., resistance to one or more agents) of 44.0% (11 of 25 isolates) and 87.5% (35 of 40 isolates) at hatcheries and broiler farms, respectively (P = 0.0002). Antimicrobial resistance among hatchery isolates was highest (28.0%) to doxycycline and kanamycin and was very high (>65%) among farm isolates to sulfamethoxazole-trimethoprim, gentamicin, ceftriaxone, kanamycin, and doxycycline. Multidrug resistance (MDR; i.e., resistance to antimicrobial agents from three or more classes) was exhibited by 4.0 and 85.7% of Salmonella isolates recovered from several environmental and animal sources at the hatcheries and farms, respectively (P < 0.0001). The high level of antimicrobial resistance and the presence of MDR among Salmonella isolates from broiler farms highlight the therapeutic implications and the potential for MDR strains to enter the food chain.The University of the West Indies, St. Augustine Campus Research and Publication Fund Committee.https://www.sciencedirect.com/journal/journal-of-food-protectionhj2023Production Animal Studie