Diana Stone

MLST genotypes and antibiotic resistance of Campylobacter spp. isolated from poultry in Grenada.

This study determined whether multilocus sequence types (MLST) of Campylobacter from poultry in 2 farms in Grenada, West Indies, differed by farm, antimicrobial resistance and farm antibiotic use. Farm A used fluoroquinolones in the water and Farm B used tetracyclines. The E-test was used to determine resistance of isolates to seven antibiotics. PCR of the IpxA gene confirmed species and MLST was used to characterize 38 isolates. All isolates were either C. jejuni or C. coli. Farm antibiotic use directly correlated with antimicrobial resistance of Campylobacter isolates. Almost 80% of the isolates from Farm A were fluoroquinolone resistant and 17.9% of the isolates from Farm B were fluoroquinolone resistant. All Campylobacter isolates from Farm A were tetracycline sensitive, whereas 35.7% of isolates from Farm B were tetracycline resistant. Six previously recognized sequence types (STs) and 2 novel STs were identified. Previously recognized STs were those overwhelmingly reported from poultry and humans globally. Isolates with the same ST did not always have the same antibiotic resistance profile. There was little ST overlap between the farms suggesting that within-farm transmission of Campylobacter genotypes may dominate. MLST typing was useful for tracking Campylobacter spp. among poultry units and can help elucidate Campylobacter host-species population structure and its relevance to human health.

INFLUENCE OF LAND USE AND CLIMATE ON SALMONELLA CARRIER STATUS IN THE SMALL INDIAN MONGOOSE (HERPESTES AUROPUNCTATUS) IN GRENADA, WEST INDIES

Abstract Invasive mammals can be important reservoirs for human pathogens. A recent study showed that 12% of mongooses carried Salmonella spp. in their large intestines. We investigated whether anthropogenic, environmental and climatic variables predicted Salmonella status in mongooses (Herpestes auropunctatus) in Grenada. Using multivariate logistic regression and contingency table analysis, we found that increased human density, decreased distance from roads, and low monthly precipitation were associated with increased probability of Salmonella carriage. Areas with higher human density likely support a higher abundance of mongooses because of greater food availability. These areas also are a likely source for infection to mongooses due to high densities of livestock and rodents shedding Salmonella. The higher probability of Salmonella carriage in mongooses during drier months and closer to roadsides is likely due to water drainage patterns and limited water availability. Although the overall prevalence of Salmonella in mongooses was moderate, the strong patterns of ecologic correlates, combined with the high density of mongooses throughout Grenada suggest that the small Indian mongoose could be a useful sentinel for Salmonella surveillance. Its affinity for human-associated habitats suggests that the small Indian mongoose is also a risk factor in the maintenance and possible spread of Salmonella species to humans and livestock in Grenada.

Prevalence and antimicrobial susceptibility of Salmonella spp. in small Indian mongooses (Herpestes auropunctatus) in Grenada, West Indies

Intestinal samples from 156 small Indian mongooses (Herpestes auropunctatus) collected island-wide in Grenada from April 2011 to March 2013 were examined for the presence of Salmonella enterica spp. Nineteen (12%) mongooses were culture-positive for S. enterica spp. of which five serotypes were identified. Salmonella javiana and S. Montevideo were the most commonly isolated serotypes. The other serotypes isolated were S. Rubislaw, S. Panama and S. Arechavaleta. All isolates were susceptible to amoxicillin-clavulanic acid, ampicillin, cefotaxime, ceftazidime, ciprofloxacin, enrofloxacin, gentamicin, nalidixic acid, imipenem and trimethoprim-sulfamethoxazole. One isolate (S. Montevideo) showed resistance to tetracycline and intermediate resistance to streptomycin. The five isolated Salmonella serotypes are potential human pathogens suggesting that the mongoose may play a role in the epidemiology of human salmonellosis in Grenada.

Genotypes, Antibiotic Resistance, and ST-8 Genetic Clone in Campylobacter Isolates from Sheep and Goats in Grenada

Rectal swabs from 155 sheep and 252 goats from Grenada were evaluated to determine the prevalence of Campylobacter spp., antibiotic resistance, and multilocus sequence types. Fifteen Campylobacter isolates were obtained (14 C. jejuni and 1 C. coli). The prevalence (3.7%) did not differ significantly between sheep (4.5%) and goats (3.2%). Among the seven antimicrobials tested, resistance was only detected for tetracycline (30.8%) and metronidazole (38.5%). Campylobacter isolates showed no significant difference between sheep and goats for type of antimicrobial resistance or percent of resistant isolates. Twelve of the isolates were successfully genotyped consisting of four recognized clonal complexes and three novel sequence types. Importantly, one isolate from one goat was identified as the C. jejuni sequence type-8, a zoonotic and tetracycline-resistant clone reported to be a highly virulent clone associated with ovine abortion in the USA. Although most samples were from comingled sheep and goat production units, there were no shared sequence types between these two host species. None of the sequence types identified in this study have previously been reported in poultry in Grenada, suggesting sheep- and goat-specific Campylobacter clones in Grenada. This is the first report of genotyping of Campylobacter isolates from sheep and goats in the Eastern Caribbean.

STREPTOCOCCUS PHOCAE IN MARINE MAMMALS OF NORTHEASTERN PACIFIC AND ARCTIC CANADA: A RETROSPECTIVE ANALYSIS OF 85 POSTMORTEM INVESTIGATIONS

ABSTRACT:  Streptococcus phocae is a pathogen of marine mammals, although its pathogenicity remains poorly understood. Recovery of this bacterium from asymptomatic carriers suggests that it is an opportunistic pathogen. We investigated the role of S. phocae in naturally occurring disease and its significance as a pathogen based on postmortem investigations. Between 2007 and 2012, 1,696 whole carcasses, tissue samples, or both were submitted from the northeastern Pacific and Arctic Canada for diagnostic testing. Streptococcus phocae was cultured from phocids (n=66), otariids (n=12), harbor porpoises (Phocoena phocoena; n=5), and sea otters (Enhydra lutris; n=2). Pathologic manifestations of S. phocae–associated disease included localized, as well as systemic, inflammatory lesions with common findings of suppurative bronchopneumonia (n=17) and bacteremia (n=27). Lung lesions were frequently culture-positive for S. phocae, suggesting commensal colonization of the oropharynx with subsequent opportunistic infection of the respiratory tract during tissue injury, coinfection, immunosuppression, or other debilitating conditions. The presence of a positive spleen culture, and interpretations at necropsy and histopathology, were used to determine the presence of S. phocae bacteremia. Less frequent lesions that were culture positive for S. phocae included abscesses (n=9), meningitis (n=7), and cellulitis (n=1). The majority of cases with S. phocae lesions featured pre-existing conditions that presumably contributed to some degree of debilitation or immunosuppression, including emaciation (n=29), liver mercury accumulation (n=29), trauma (n=22), severe pulmonary or cardiovascular nematodiasis (n=9), concurrent bacterial or viral infections (n=8), or sarcocystosis (n=6). These findings suggest that S. phocae could be characterized as an opportunistic pathogen, associated with debilitating conditions in stranded and rehabilitating marine mammals. Wildlife investigators can use these results to draw more definitive conclusions regarding positive S. phocae cultures during postmortem studies in marine mammals.

Initial development and preliminary evaluation of a multiplex bead assay to detect antibodies to Ehrlichia canis, Anaplasma platys, and Ehrlichia chaffeensis outer membrane peptides in naturally infected dogs from Grenada, West Indies:

Tick-borne bacteria, Ehrlichia canis, Anaplasma platys, and Ehrlichia chaffeensis are significant pathogens of dogs worldwide, and coinfections of E. canis and A. platys are common in dogs on the Caribbean islands. We developed and evaluated the performance of a multiplex bead-based assay to detect antibodies to E. canis, A. platys, and E. chaffeensis peptides in dogs from Grenada, West Indies, where E. canis and A. platys infections are endemic. Peptides from outer membrane proteins of P30 of E. canis, OMP-1X of A. platys, and P28-19/P28-14 of E. chaffeensis were coupled to magnetic beads. The multiplex peptide assay detected antibodies in dogs experimentally infected with E. canis and E. chaffeensis, but not in an A. platys experimentally infected dog. In contrast, the multiplex assay and an in-house enzyme-linked immunosorbent assay (ELISA) detected A. platys antibodies in naturally infected Grenadian dogs. Following testing of 104 Grenadian canine samples, multiplex assay results had good agreement with commercially available ELISA and immunofluorescent assay for E. canis antibody-positive dogs (K values of 0.73 and 0.84), whereas A. platys multiplex results had poor agreement with these commercial assays (K values of −0.02 and 0.01). Prevalence of seropositive E. canis and A. platys Grenadian dogs detected by the multiplex and commercial antibody assays were similar to previous reports. Although the multiplex peptide assay performed well in detecting the seropositive status of dogs to E. canis and had good agreement with commercial assays, better antigen targets are necessary for the antibody detection of A. platys.

A survey of canine heartworm awareness in Grenada, West Indies.

Heartworm is a common parasite of dogs in Grenada, West Indies, due to the tropical climate and large number of mosquitoes. Because Grenada is a developing country and a small island, resources and education on heartworm are limited. In an effort to raise awareness of canine heartworm and the preventive measures available, observations and surveys were performed to determine the following: (a) heartworm knowledge among Grenadian dog caregivers seeking veterinary care at the Grenada Society for the Prevention of Cruelty to Animals (GSPCA), (b) dissemination of heartworm information by GSPCA staff to Grenadian dog caregivers, and (c) reasons Grenadians are not administering heartworm prevention to their dogs. Results indicated a marked deficiency in both heartworm knowledge among Grenadian dog caregivers and heartworm knowledge acquisition and dissemination. Lack of knowledge was also cited as a major reason Grenadian dog caregivers were not using heartworm prevention. These results are currently being utilized to modify heartworm education practices at the GSPCA by incorporating Grenada-specific educational tools, with the ultimate goal of reducing illness and death by canine heartworm.

Neoplastic and Nonneoplastic Cutaneous Tumors of Dogs in Grenada, West Indies

This retrospective survey was undertaken between 2002 and 2007 on samples from dogs residing in Grenada. The objectives of the study were to identify the most common histologic types of canine cutaneous tumors, determine the relative frequency of each tumor type, and compare results to reports from other regions. In a series of 225 skin masses examined, the proportion of neoplasms was 72% whereas nonneoplastic tumors accounted for 15.6%, and inflammatory conditions constituted 12.4%. There were 10 types of nonneoplastic tumors with hamartomas being the most common (28.5%), followed by sebaceous hyperplasia (25.7%) and fibroepithelial polyps (22.8%). The 10 most common cutaneous neoplasms were hemangiosarcomas (19.1%), histiocytomas (8.6%), melanocytomas (8%), mast cell tumors (6.8%), lipomas (6.8%), hemangiopericytomas (6.2%), papillomas (5.6%), fibrosarcomas (5.6%), hemangiomas (4.9%), and squamous cell carcinomas (4.3%). Tumors of vascular origin and transmissible venereal tumors were more common in dogs in our study than reported from other regions.