Staphylococcus pseudintermedius and Staphylococcus schleiferi Subspecies coagulans from Canine Pyoderma Cases in Grenada, West Indies, and Their Susceptibility to Beta-Lactam Drugs.

Over a 2-year period 66 cases of canine pyoderma in Grenada, West Indies, were examined by aerobic culture in order to ascertain the bacteria involved and their antimicrobial resistance patterns. Of the 116 total bacterial isolates obtained, the majority belonged to Gram-positive species, and the most common organism identified through biochemical and molecular methods was Staphylococcus pseudintermedius. Additionally, identification of a Staphylococcus schleiferi subspecies coagulans isolate was confirmed by molecular methods. All isolates of staphylococci were susceptible to beta-lactam drugs: amoxicillin-clavulanic acid, cefovecin, cefoxitin, cefpodoxime, and cephalothin. They were also susceptible to chloramphenicol and enrofloxacin. Resistance was highest to tetracycline. Methicillin resistance was not detected in any isolate of S. pseudintermedius or in S. schleiferi. Among the Gram-negative bacteria, the most common species was Klebsiella pneumoniae, followed by Acinetobacter baumannii/calcoaceticus. The only drug to which all Gram-negative isolates were susceptible was enrofloxacin. This report is the first to confirm the presence of S. pseudintermedius and S. schleiferi subspecies coagulans, in dogs with pyoderma in Grenada, and the susceptibility of staphylococcal isolates to the majority of beta-lactam drugs used in veterinary practice.

Prevalence, serovars, and antimicrobial susceptibility of Salmonella isolated from blue land crabs (Cardisoma guanhumi) in Grenada, West Indies.

Samples of intestine and hepatopancreas from 65 blue land crabs (Cardisoma guanhumi), a crustacean commonly consumed as a food item in Grenada, were collected from six geographic sites in Grenada and tested for Salmonella by enrichment and selective culture. The individual animal prevalence of Salmonella based on isolation was 17% (11 of 65), and all infected crabs were from three of the six sampled locations. Isolates were identified by serotyping as Salmonella enterica serovars Saintpaul (n = 6), Montevideo (n = 4), and Newport (n = 1). The intestines of all 11 infected crabs were positive for Salmonella, but only 7 of 11 hepatopancreas samples were positive for Salmonella, and these isolates were the same serovar as isolated from the matching intestine. These three Salmonella serovars are known to cause human illness in many countries, and in the Caribbean Salmonella Saintpaul has been frequently isolated from humans. In a disc diffusion assay, all isolates were susceptible to all 11 drugs tested: amoxicillin-clavulanic acid, ampicillin, cephalothin, chloramphenicol, ciprofloxacin, gentamicin, imipenem, neomycin, streptomycin, tetracycline, and trimethoprim-sulfamethoxazole. To our knowledge, this report is the first concerning isolation and antimicrobial susceptibilities of Salmonella serotypes from the blue land crab.

Aerobic bacteria from mucous membranes, ear canals, and skin wounds of feral cats in Grenada, and the antimicrobial drug susceptibility of major isolates.

In a 2-year period 54 feral cats were captured in Grenada, West Indies, and a total of 383 samples consisting of swabs from rectum, vagina, ears, eyes, mouth, nose and wounds/abscesses, were cultured for aerobic bacteria and campylobacters. A total of 251 bacterial isolates were obtained, of which 205 were identified to species level and 46 to genus level. A commercial bacterial identification system (API/Biomerieux), was used for this purpose. The most common species was Escherichia coli (N=60), followed by Staphylococcus felis/simulans (40), S. hominis (16), S. haemolyticus (12), Streptococcus canis (9), Proteus mirabilis (8), Pasteurella multocida (7), Streptococcus mitis (7), Staphylococcus xylosus (7), S. capitis (6), S. chromogenes (4), S. sciuri (3), S. auricularis (2), S. lentus (2), S. hyicus (2), Streptococcus suis (2) and Pseudomonas argentinensis (2). Sixteen other isolates were identified to species level. A molecular method using 16S rRNA sequencing was used to confirm/identify 22 isolates. Salmonella or campylobacters were not isolated from rectal swabs. E. coli and S. felis/simulans together constituted 50% of isolates from vagina. S. felis/simulans was the most common species from culture positive ear and eye samples. P. multocida was isolated from 15% of mouth samples. Coagulase-negative staphylococci were the most common isolates from nose and wound swabs. Staphylococcus aureus, or S. intemedius/S. pseudintermedius were not isolated from any sample. Antimicrobial drug resistance was minimal, most isolates being susceptible to all drugs tested against, including tetracycline.

Antimicrobial susceptibility of clinical isolates of Pseudomonas aeruginosa from dogs in Grenada

A total of 44 isolates of Pseudomonas aeruginosa were recovered from various clinical conditions during the last 5 years from dogs in Grenada. The majority of isolates originated from otitis, and skin conditions including dermatitis, wounds, and abscesses. The isolates were tested for their susceptibility to 6 antibiotics using a standard disk diffusion test. Resistance was least to gentamicin (9.8%), followed by enrofloxacin (15.8%), and neomycin (41.8%). Resistance to tetracycline was 85.3%, and all isolates showed inherent resistance to amoxicillin-clavulanic acid and cephalothin.

Clinical isolates of bacteria from domestic cats in Grenada, and their antimicrobial susceptibility

Of a total of 57 consecutive clinical samples from domestic cats in Grenada, 23 were culture positive for aerobic bacteria. Of 25 isolates from these samples, 13 were Gram-negative bacteria, the majority (54%) being Escherichia coli from urinary tract infections and wounds/ abscesses, followed by Pseudomonas aeruginosa. Of the 12 Gram-positive isolates, the majority (75%) were staphylococci, originating from various infections. Among the less common isolates were, an Enterobacter cloacae strain associated with otitis externa, an Enterococcus faecalis strain associated with urinary tract infection, and a Streptococcus pneumoniae strain associated with upper respiratory infection. Antimicrobial resistance was least to enrofloxacin, the rate being 5.2%, followed by gentamicin (12%), chloramphenicol (14.2%), amoxicillin-clavulanic acid (15%), cephalothin (20%), and tetracycline (38.1%). All Gram-negative isolates were susceptible to enrofloxacin, and all Gram-positives to amoxicillin-clavulanic acid.

Antimicrobial drug resistance as determined by the E-test in Campylobacter jejuni, C. coli, and C. lari isolates from the ceca of broiler and layer chickens in Grenada.

One hundred and twenty five chickens from Grenada, consisting of 77 broilers and 48 layers were examined for carriage of thermophilic campylobacters in their ceca by culture. Seventy nine percent of chickens were positive for campylobacters, with an isolation rate of 93.5% for broilers and 56.3% for layers, the difference being significant. Sixty-four pure cultures comprising 39 Campylobacter coli, 21 Campylobacter jejuni, and 4 Campyilobacter lari isolates were tested for their resistance against 7 antibiotics using the E-test. None of the isolates were resistant to chloramphenicol and gentamicin. Resistance rates to other drugs were: ampicillin, 9.4%; ciprofloxacin, 12.5%; erythromycin, 3.1%; metronidazole, 9.4%, and tetracycline, 50% with MICs of >or=256 microg/mL for tetracycline. There were no significant differences in resistance rates between C. coli and C. jejuni. Multiple resistance to >or=2 drugs was seen in 15.6% of total isolates. All C. lari isolates were resistant to ciprofloxacin, and 3 of 4 isolates had multiple drug resistance. Overall, erythromycin, which is the drug of choice for treatment of Campylobacter infections in humans, is effective in vitro against 97% of chicken isolates in Grenada.