Spencer S. Jang

Apparent Outbreaks of Clostridium Difficile-Associated Diarrhea in Horses in a Veterinary Medical Teaching Hospital

Intestinal colonization with toxigenic strains of Clostridium difficile was documented in 9 of 10 horses with acute onset diarrhea in a veterinary medical teaching hospital, whereas a similar isolate was detected in only 1 of 23 other horses without diarrhea in the hospital. One horse with diarrhea was infected simultaneously with both C. difficile and Salmonella krefeld. Clostridium difficile was detected by fecal culture on selective medium, confirmed with a latex particle agglutination test, and identified as toxigenic by polymerase chain reaction amplification of toxin A and toxin B gene sequences. Using an arbitrarily-primed polymerase chain reaction, 6 distinct C. difficile isolates were detected in the feces of the 9 affected horses at the time of the outbreak of diarrhea.

Salmonella and Campylobacter spp. in Northern Elephant Seals, California

Campylobacter and Salmonella spp. prevalence and antimicrobial drug sensitivity were determined in northern elephant seals that had not entered the water and seals that were stranded on the California coast. Stranded seals had a higher prevalence of pathogenic bacteria, possibly from terrestrial sources, which were more likely to be resistant.

Fusobacterium canifelinum sp. nov., from the Oral Cavity of Cats and Dogs

Fourteen strains of Gram-negative, anaerobic, fluoroquinolone-resistant, non-sporulating rods were isolated from various infections in cats and dogs, as well as from wounds in humans after cat- or dog-bites. These strains were characterized by sequencing of the 16S-23S rDNA internal transcribed spacer (ITS) regions, 16S rDNA, DNA-DNA hybridization, phylogenetic analysis, and phenotypic tests. The results indicate that the novel strains belong to a distinct species, closely related to Fusobacterium nucleatum. The species Fusobacterium canifelinum sp. nov. is proposed, with strain ATCC BAA 689T as the type strain.

Histoplasmosis infection in two cats from California

Systemic mycotic infections are typically localized to specific geographic regions of the country, because the organisms involved have certain environmental requirements for growth. Suspicion of infection relies on travel to or residence in recognized endemic regions. This report describes infection with histoplasmosis in two indoor cats from central California, an area not considered to be endemic for the disease. Systemic mycotic infections should be considered as differential diagnoses in any cat with compatible clinical signs, regardless of travel history or residence, especially if the cat is presented within a recognized endemic region.

Distribution of indole-producing urease-negative pasteurellas in animals

Three hundred fifty-six animal isolates of indole-positive urease-negative cultures of Pasteurella, which would formerly have been classified as P. multocida, were examined with respect to their relationship to the recently described P. multocida subspecies (ssp.) multocida, septica, and gallicida and P. canis, P. stomatisl Taxon 16, and Pasteurella sp. B. Two hundred sixty-three (73.9%) of the cultures could be identified with one of these taxa, and 93 isolates (26.1%), representing 17 different biotypes, were unassignable. Pasteurella multocida ssp. multocida was the predominant taxon throughout and in most of the 25 animal species from which isolations were made. In dogs, P. canis was the most frequent. Different degrees of host predilection were observed also in P. multocida ssp. septica for cats, P. canis for sheep, and 2 of the unassignable biotypes for cattle and dogs, respectively. Overall, the respiratory tract was the most frequent source of isolates, but a propensity of P. multocida ssp. septica for localization in the central nervous system of cats was noted.

Rapidly growing members of the genus Mycobacterium affecting dogs and cats.

Rapidly growing members of the genus Mycobacterium were most often associated with chronic (2 to 72 months), nonhealing skin lesions of dogs and cats. Mycobacterium fortuitum (M. fortuitum) was the most commonly isolated mycobacterium obtained from these lesions, although M. chelonae-abscessus and M. flavescens were occasionally encountered. Isolates were tested in vitro to various antimicrobial agents and found to be susceptible to amikacin (100% of the isolates), cefoxitin (93.8%), ciprofloxacin (75%), clarithromycin (71.4%), doxycycline (28.6%), erythromycin (6.2%), gentamicin (68.8%), kanamycin (75%), minocycline (81.3%), streptomycin (14.3%), tobramycin (43.8%), trimethoprim/sulfonamides (57.1%), and vancomycin (15.4%).

Virulence factors in Escherichia coli isolated from the blood of bacteremic neonatal calves

Twenty-five Escherichia coli isolates from the blood of critically ill bacteremic calves sampled in two separate studies on a calf-rearing farm housing over 15,000 calves, in the San Joaquin Valley, California were studied. Isolates were characterized for O serogroups and for pathotypes as determined by the presence of specific virulence factors including heat-labile enterotoxin (LT), heat-stable enterotoxins a and b (STa, STb), verotoxins 1 and 2 (VT1, VT2), cytotoxic necrotizing factor (CNF), aerobactin, intimin Eae and P, F17 and CS31A fimbrial adhesins, and resistance to bactericidal effects of serum. These isolates constituted a heterogeneous group. However, isolates were mostly aerobactin positive and often resistant to the bactericidal effects of serum. Isolates of pathotypes O78 (n=6), O119:CS31a (n=3), and P positive but O non-typeable (n=3) were associated with a high mortality rate. The remaining isolates belonged to diverse pathotypes, often possessing the adhesins P, F17, CS31A and Eae but belonging to O serogroups other than O78 and O119, and were less frequently associated with mortality. Although no virulence factor common to all isolates was identified, the capacity to use iron by the presence of aerobactin which is important to the capture of iron was a predominant factor. Moreover, certain pathotypes appear to be associated with primary colisepticemia whereas other pathotypes may cause a bacteremia without necessarily leading to septicemia.

Prevalence and characterization of Salmonella spp. among marine animals in the Channel Islands, California.

Salmonella enterica is a zoonotic pathogen that has been isolated from free-ranging marine mammals throughout the world, with animals in the Channel Islands of California (USA) showing the highest prevalence. The goal of this study was to determine prevalence, antimicrobial sensitivity and genetic similarity using pulsed-field gel electrophoresis (PFGE) of Salmonella in several non-domestic animal species on San Miguel and San Nicolas Islands. Fecal samples were collected from 90 California sea lion Zalophus californianus pups, 30 northern elephant seal Mirounga angustirostris pups and 87 western gulls Larus occidentalis in the Channel Islands and 59 adult male sea lions in Puget Sound, WA (USA). Salmonella were isolated, identified and serotyped, followed by antimicrobial susceptibility testing and PFGE. Of the California sea lion pups that were sampled on the islands, 21% (n = 19) were positive for Salmonella, whereas no adults males in Puget Sound were positive. Of the northern elephant seal pups sampled, 87% (n = 26) were harboring Salmonella. Only 9% (n = 8) of western gulls were shedding Salmonella, with one of these gulls harboring the only antimicrobial resistant isolate. The serotypes found in these animals were Enteritidis, Montevideo, Newport, Reading, and Saint Paul. The only serotype that showed variation on PFGE was Newport. The pinnipeds of the Channel Islands harbor Salmonella at a higher prevalence than pinnipeds from other geographic areas observed in previous studies. Researchers and veterinarians should exercise increased caution when working with these animals due to the zoonotic potential of Salmonella.

Risk factors for infection with pathogenic and antimicrobial-resistant fecal bacteria in northern elephant seals in California.

Objectives. The goal of this study was to identify potential environmental and demographic factors associated with Campylobacter jejuni (C. jejuni), Salmonella enterica (Salmonella spp.), and antimicrobial-resistant Escherichia coli (E. coli) infection in northern elephant seals stranded along the California coastline. Methods. E. coli, Salmonella spp., and C. jejuni were isolated from rectal swabs from 196 juvenile northern elephant seals, which were found stranded and alive along the California coast and brought to The Marine Mammal Center in Sausalito, California, for rehabilitation. Gender, weight, county where the animal stranded, month stranded, coastal human population density, exposure to sewage outfall or freshwater outflow (river or stream), and cumulative precipitation in the previous 24 hours, seven days, 30 days, 90 days, and 180 days were analyzed as potential risk factors for infection. Results. The odds of C. jejuni and antimicrobial-resistant E. coli were higher in feces of seals stranded at sites with higher levels of freshwater outflow compared with lower levels of freshwater outflow. The odds of Salmonella spp. in feces were 5.4 times greater in seals stranded in locations with lower levels of 30-day cumulative precipitation, along with substantially lower odds of Salmonella shedding for seals stranded in Monterey or Santa Cruz county compared with seals stranded in regions further north or south of this central California location. Conclusions. Juvenile northern elephant seals that have entered the water are being colonized by antimicrobial-resistant and pathogenic fecal bacteria that may be acquired from terrestrial sources transmitted via river and surface waters.

CHARACTERIZATION AND CLINICAL MANIFESTATIONS OF ARCANOBACTERIUM PHOCAE INFECTIONS IN MARINE MAMMALS STRANDED ALONG THE CENTRAL CALIFORNIA COAST

Between 1994 and 2000, 141 Arcanobacterium phocae isolates were recovered from marine mammals that stranded along the central California coast (USA). Arcanobacterium phocae was cultured from tissue sites with abnormal discharge or evidence of inflammation in 66 California sea lions (Zalophus californianus), 50 Pacific harbor seals (Phoca vitulina richardii), 19 northern elephant seals (Mirounga angustirostris), five southern sea otters (Enhydra lutris nereis), and one common dolphin (Delphinus delphis). The overall prevalence of A. phocae among cultured stranded marine mammals was 8%. This is the first report of A. phocae in animals from the Pacific Ocean. Sequence analysis of a portion of the 16S ribosomal RNA gene confirmed recent isolates as A. phocae. Prior to phylogenetic testing and the routine use of the esculin hydrolysis and motility tests, A. phocae isolates may have been misidentified as Listeria ivanovii. Arcanobacterium phocae was commonly isolated from superficial abscesses, was often present in mixed infections, and was susceptible to all antimicrobial agents tested.