ISOLATION AND CHARACTERIZATION OF YERSINIA SPECIES FROM CHICKENS AROUND ZAR1A

No Thumbnail Available
Date
2014-09-08
Authors
EVELYN, NNENN1A NWOSUH
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
The study was conducted to determine the prevalence of Yersinia spp. infection in chickens kept under different management systems in Zaria area using cultural and serologic means. All isolates were fully characterized. In addition, experimental studies were conducted in chickens exposed to Y. enterocolitica by the oral and intravenous routes. Five (0.63%) strains of Y. enterocolitica were i s o l a t ed from 800 cloacal swabs of chickens kept under the extensive ( free-range ) , semi-intensive and intensive management systems. All samples were enriched in 0.67m phosphate buffered saline, pH 7.6 for 3 weeks and plated on desoxycholate citrate agar and MacConkey agar. All 5 s t r a i n s came from chickens kept under the extensive management system ana were of serotype 0:12,25, biotype 3 and ptoagetype Xz. Biochemically, all reactions of the isolates were typical for Y. enterocolitica but for the utilization of citrate by all and Voges-Proskauer positive results at 370 C for two isolates. Only as train (ZM12) was positive for all 4 virulence markets assayed for, namely, calcium dependency at 370 C, autoagglutination at 37 C, invasiveness in guinea-pig eye (sereny t e s t ) and production of heat-stable (ST) enterotoxin as detected by the infant mouse system (IMS). The IMS was found to be more sensitive in detecting ST enterotoxin with 4 of 5 strains being positive, than the rabbit ileal loop system where filtrates of supernatant of the 5 strains were negative. In vitro activities of the antimicrobial agents tested by the disc and agar dilution metnods demonstrated that neomycin, kanamycin, gentamycin, nalidixic acid, colistin sulphate and sulphamethoxazole-Trimethoprim (SXT) were most effective against Y. enterocolitica strains from chickens. An overall antibody prevalence of 1.9% was detected against serotypes 0:3, 0:5, 27, 0:8, 0:9 and 0:12,26 screened for in 800 serum samples obtained from the extensive and intensive systems of management. All sere, were negative for agglutinins against serotypes 0:5,27, 0:8 and 0:12,26 but 4(0.5%) and 11(1.4%) were positive for antibodies to serotypes 0:3 and 0:9 respectively. 9 Experimental inoculation, by the oral route, of 10 to 101 1 cells of 3 serotypes of Y. enterocolitica into day-old broiler chicks did not cause any overt clinical signs. Weight gain in infected chickens was not affected over the study period. Colonization of the gut of infected chickens was minimal with Y. enterocolitica shed in faeces for only a few days. Administration of 10% NaHCO3 had no significant effect on colonization of the gut of chickens by Y. enterocolitica. Of public health significance was the detection of Y. enterocolitica in the liver, spleen, heart and bile of some experimentally exposed but apparently healthy chickens, 10 Three-week old chicks inoculated with 1.0x10 and 2.1x10 cells of Y. enterocolitica by the intravenous route showed initial clinical signs like diarrhoea, depression and loss of appetite but recovery was completed within 24hrs in most chicks. It was concluded that the rather high environmental temperature in Nigeria, a tropical country coupled with the relatively high normal body temperature of chickens may be responsible, in part, for the low prevalence of Y. enterocolitica infection detected in the present study. This is because the organism has affinity for low temperature.
Description
A thesis submitted to Ahmadu Bello University, Zaria in partial fulfilment for the degree of MASTER OF SCIENCE Department of Veterinary Public Health and Preventive Medicine Ahmadu Bello University, Zaria
Keywords
ISOLATION,, CHARACTERIZATION,, YERSINIA,, SPECIES,, CHICKENS,, AROUND ZAR1A
Citation