Isolation and identification of Caviibacter abscessus from cervical abscesses in a series of pet guinea pigs (Cavia porcellus).

An organism reported in the early literature to be a rare cause of cervical lymphadenitis in guinea pigs, Streptobacillus moniliformis, has been reclassified as Caviibacter abscessus We describe a series of sequential cases of abscesses in guinea pigs that were presented to our clinic from which the only agent isolated was a unique, serum-requiring bacterium. Discrete colonies were not detected in 6.5% CO2 or anaerobically on routine primary isolation media containing up to 5% whole sheep blood, with and without cysteine, vitamin K, and hemin supplementation after 7 days of incubation at 37°C. Based on subsequently determined growth requirements, the organisms were best described as serum-requiring, aerotolerant anaerobes. Colonies were detectable within 24 h at 37°C in an anaerobic atmosphere on a mycoplasma agar-based medium containing 10% pig serum and reached 3 mm in diameter within 3-5 days. Microscopic appearance consisted of small gram-negative rods and coccobacilli with occasional filaments. However, in direct smears from clinical specimens and from weak or dysgonic growth on plates incubated under suboptimal growth conditions (e.g., in 6.5% CO2), irregular rods with occasional small bulbous forms or numerous long wavy filaments were observed. All of the isolates generated unique spectral profiles similar to that of C. abscessus when examined by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Phylogenetic analysis of partial 16S rRNA gene sequences showed that the isolates were identical to each other and shared 99.9% sequence identity with C. abscessus.

Synergistic hemolysis between ß-lysin-producing Staphylococcus species and Rothia nasimurium in primary cultures of clinical specimens obtained from dogs.

Nonhemolytic isolates of catalase-positive, Gram-positive cocci were observed that produced strong synergistic hemolysis with colonies of Staphylococcus pseudintermedius and Staphylococcus schleiferi subsp. coagulans in primary cultures of clinical specimens from dogs. The isolates appeared similar to nonhemolytic staphylococci but were not identified with conventional biochemical tests or commercial biochemical test kits. Partial 16S ribosomal RNA gene sequences from each of 9 tested isolates were nearly identical to that of Rothia nasimurium. The isolates produced positive Christie-Atkins-Munch-Peterson test reactions with Staphylococcus aureus (ATCC strain 25923) and Staphylococcus intermedius Hajek (ATCC strain 49052). The latter was identified in the current study as S. pseudintermedius. Rothia nasimurium appears to be a previously unreported commensal organism in dogs. Its potential significance as an opportunistic contributor to polymicrobial infections in dogs is not known.

Isolation of a variant Porphyromonas sp. from polymicrobial infections in central bearded dragons (Pogona vitticeps).

Isolates of gram-negative anaerobic bacteria from reptiles have only occasionally been identified to the genus and species level in the veterinary medical literature. In particular, reports identifying Porphyromonas spp. from infections in reptiles are scarce. The present report describes unique Porphyromonas isolates obtained from necrosuppurative infections in central bearded dragons (Pogona vitticeps). The isolates grew in the presence of oxygen, were strongly hemolytic, and did not produce detectable black, iron porphyrin pigment. Biochemical identification kit numeric biocodes gave high but unreliable probabilities (>99.9%) for identification as Porphyromonas gingivalis. Partial 16S ribosomal RNA gene sequences of the isolates were identical to each other and shared 91% identity with those of Porphyromonas gulae. The isolates may represent a new reptile-associated Porphyromonas species.

Isolation of Propionibacterium acnes from a case of placentitis and abortion in a cow.

On the basis of the scarcity of reports in the veterinary literature, it appears that Propionibacterium spp. are rarely associated with disease or isolated from cattle tissues. Recently, Propionibacterium spp. has been associated with multifocal abscessation in cattle. This report describes a case of necrosuppurative placentitis and abortion in an adult Holstein cow. Numerous colonies of small, pleomorphic, Gram-positive, rod-shaped bacteria were observed within the fibrin lattice associated with placental lesions and within the fetal atelectatic lung. Propionibacterium acnes was isolated in high numbers from the placenta, fetal lung, and stomach contents. To the authors' knowledge, this is the first report of placentitis associated with propionibacteria in a cow.

Isolation of Arcanobacterium hippocoleae from a case of placentitis and stillbirth in a mare.

Based on the scarcity of reports in veterinary medicine literature, it appears that Arcanobacterium spp. are rarely isolated from horses. Recently, a single isolate from vaginal discharge in a mare was characterized as a new species, Arcanobacterium hippocoleae. The present report describes a case of necrosuppurative placentitis and stillbirth in an American Quarterhorse mare. Numerous colonies of irregular, Gram-positive, rod-shaped bacteria were observed by histological examination within fibrin lattice associated with placental lesions. Arcanobacterium hippocoleae was isolated in large numbers from the placenta, lung, and stomach contents. To the authors' knowledge, this is the first report of placentitis associated with Arcanobacterium spp. in a horse and the third reported isolation of A. hippocoleae from a horse.