Plasmid profile analysis of bovine isolates of Pasteurella haemolytica

Pasteurella haemolytica isolates, obtained from cattle with respiratory tract disease, were characterized as to serotype, antimicrobial susceptibility, and plasmid content. Strains isolated from 2 groups of cattle were compared. Remarkable similarity was seen in the plasmid profiles of isolates of the same serotype. In contrast, isolates of 2 different serotypes had totally different plasmid profiles.     

Plasmid profile analysis, phage typing, and antibiotic sensitivity of Salmonella dublin from clinical isolates in the United States.

One hundred clinical isolates of Salmonella choleraesuis subsp. choleraesuis serovar dublin (Salmonella dublin) were examined for phage sensitivity, antibiotic resistance patterns, and plasmid content. Computer analysis of the lysis patterns observed by using 27 typing phages divided the S. dublin isolates into 26 groups. One lytic pattern (Designated pattern 16) contained 52% of the isolates examined whereas 16 isolates had unique patterns, and nine patterns had fewer than ten members. Although 14 antibiotic resistance patterns were observed among the 100 isolates, 79% of the isolates grouped in three major patterns. Seven plasmid groups were identified and designated A-G based on the large plasmids found in the isolates. Of the 100 isolates, 28 contained the plasmid profile of Group A, 28 were Group B, 7 were Group C, 34 were Group D, and 1 isolate each was observed in Groups E, F, and G. The strong association between antibiotic resistance pattern and plasmid type suggest that the drug resistance genes are plasmid borne.     

Detection of salmonellae from fish in a natural river system

Sediment, water, and fish gut samples taken at three sites near the headwaters of the San Marcos River, Texas, were analyzed for salmonellae Salmonella spp. by culture and molecular techniques. While enrichment cultures from sediment and water samples from the two uppermost sites were negative for salmonellae in polymerase chain reaction analyses, both sediment and water samples were positive at the downstream site. At all sites, salmonellae were present in the guts of different fishes (e.g., largemouth bass Micropterus salmoides, channel catfish Ictalurus punctatus, common carp Cyprinus carpio, and suckermouth catfish Hypostomus plecostomus). The highest percentage of detection (33% of analyzed fish) occurred at the downstream site, whereas detection percentages at the upper two sites were 18% and 17%. Detection of salmonellae was usually limited to one segment of the gut (i.e., upper or lower part). Serovars were highly variable among individuals and differed between the upper and lower gut in the only individual (a common carp) that had salmonellae in both gut segments. In situ hybridization demonstrated that salmonellae were normally associated with particulate material in the gut and occurred in highly variable numbers ranging from an occasional organism to a majority of the gut microbe population. These results demonstrate the presence of different serovars of potentially human pathogenic salmonellae among four ecologically distinct fishes within natural environments. They also suggest that salmonellae are not components of the indigenous microbial community in fish intestines but rather are ingested with particulate material.     

Experiential learning in the animal sciences: development of a multispecies large-animal management and production practicum

Students enrolled in an introductory animal science course (ASG 3003) at the University of Florida were surveyed (n = 788) over a 3-yr period to ascertain their current experience and career goals in animal agriculture. Sixty-one percent of the students indicated that they were from an urban background. Only 4% were raised on a farm or ranch where the majority of family income was attributed to production agriculture. Eighty-six percent of the students had minimal or no experience working with large domestic farm animals, but nearly 64% of the students wanted to pursue a career in veterinary medicine. Disciplinary and species interests of the students were highly associated with previous background experiences. Students from nonagricultural backgrounds, who were most likely to indicate a career interest involving veterinary medicine, were most interested (P < 0.05) in animal behavior, whereas the students of rural background were more interested (P < 0.05) in animal management. Thirty-three percent of students were primarily interested in small companion animals; 22% in horses; 20% in domestic farm animals, including beef, dairy, swine, or sheep; and 24% in undomesticated zoo animals or wildlife. The career goals indicated by most students necessitate practical application of animal husbandry skills that are often assumed as general knowledge. Thus, a multispecies large animal management and production practicum (ANS 3206) was developed to provide students with hands-on experience. It was an elective course, and students were encouraged to enroll for two consecutive semesters. Teams of students rotated responsibilities among four livestock species (beef, dairy, equine, and swine). Daily responsibilities at each of the units included feeding and monitoring growth of feedlot cattle and finishing swine, farrowing assistance and baby pig processing, and equine training and foaling assistance. Students were also involved with all facets of a working dairy. Additionally, students completed written assignments specific to their individual species responsibilities that included daily journals, worksheets, or calculation of performance measures. Weekly class meetings allowed for instruction and were used to manage the varied course activities. Using a 5-point scale (1 = poor, 5 = excellent), students indicated that the course further stimulated their interest (4.73) and facilitated their learning (4.63) of animal science concepts. Overall course evaluations ranged from 4.54 +/- 0.55 to 4.85 +/- 0.38 over a 4-yr period. As more students enter animal science programs with nonagricultural backgrounds, it will become necessary to reemphasize basic animal-handling skills and practical applications through experiential learning activities.     

Plasmid profile and phage type of Salmonella typhimurium strains encountered in different regions of India

A total of 190 Salmonella typhimurium strains encountered in different parts of India were characterized on the basis of plasmid profile, phage type and antimicrobial resistance pattern. Recent trends in the epidemiology of R-plasmids were also studied.

The majority of S. typhimurium strains (90.5%) were untypable by phage typing. Only 18 strains (9.5%) were phage typable. The phage untypable strains isolated from northern (57) central (65), and southern (50) regions of India could be subgrouped into 24, 12 and 16 different plasmid profiles respectively. Heterogeneity was the prominent feature although most of the plasmid profiles were related among strains isolated from particular place. A great diversity among small plasmids (2.7–8.3 kb) made subgrouping of majority strains (71%) with R-pattern ApCmKmSmSuTcTp possible. Conjugation studies and plasmid profile analysis of transconjugants revealed all the strains to harbour non conjugative non-auto transmissible plasmids with the exception of 7.2 and 2.7 kb plasmids which were not mobilizable.     

The microflora of the cervix of the thoroughbred mare: A clinical and bacteriological survey in a large-animal practice in Hastings

Abstract

Extract

Many reports concerned with the microflora of the genital tract in thoroughbred mares stress the potential pathogenic significance of the haemolytic streptococci. Many years ago, Dimock (1929 Dimock, W. W. 1929. Breeding diseases of the horse. J. Am. vet. med. Ass., 74: 327–335.  [Google Scholar], 1939 Dimock, W. W. 1939. Equine breeding hygiene. J. Am. vet. med. Ass., 94: 469–478.  [Google Scholar]) and Dimock and Edwards (1928) Dimock, W. W. and Edwards, P. R. 1928. The pathology and bacteriology of the reproductive organs of mares in relation to sterility. Ky agric. exp. Stn Bull., 286: 287–339.  [Google Scholar] associated the haemolytic streptococci with persistent endometritis, sterility and deaths in foals up to 2 to 4 weeks after birth. In Holland, Ressang (1954) Ressang, A. 1954. “Sterility in Mares. A clinical, bacteriological and histopathological investigation”. In Thesis, State University of Utrecht.  [Google Scholar] isolated haemolytic streptococci of Lancefield's Group C from 34 of 153 (22%) mares offered for examination because of poor breeding performance. Ressang noted that mares with streptococcal endometritis were not likely to show satisfactory fertility even after the infection had apparently been eliminated. Haemolytic streptococci have also been associated with infertility in mares in Turkey (Pusat, 1955 Pusat, M. M. 1955. Kisraklarin sikit amili streptococlarin tipleri ve streptococcus genitalium uzerinde bir munakasa. Turk vet. Hekim. Dern. Derg., 24: 2,039–2,047.  [Google Scholar]), in the United Kingdom (Moran and Cronin, 1957 Moran, A. B. and Cronin, M. T. 1957. Organisms isolated from the uteri of thoroughbred mares. J. comp. Path., 67: 106–109.  [Google Scholar]) and in Ireland (Farrelly and Mullaney, 1964 Farrelly, B. T. and Mullaney, P. E. 1964. Cervical and uterine infection in thoroughbred mares. Ir. vet. J., 18: 201–212.  [Google Scholar]). In Australia, Bain (1966) Bain, A. M. 1966. The role of infection in infertility in the thoroughbred mare. Vet. Rec., 78: 168–173.  [Google Scholar] noted that 12% of infected mares at stud in the Hunter district of New South Wales harboured beta-haemolytic strepotcocci in the genital tract. This organism was considered the most serious pathogen encountered as only 40% of these mares infected with haemolytic streptococci produced a live foal in the first year following infection: 35% had still not completed a successful pregnancy within the subsequent 3-year period.