Combination chemotherapy of canine and feline cryptococcosis using subcutaneously administered amphotericin B

Six cases (3 cats, 3 dogs) of cryptococcosis were cured using combination chemotherapy that included amphotericin B. We developed a simple, practical and inexpensive method of administering amphotericin B as a subcutaneous infusion during the treatment of these patients. For this, the calculated dose of amphotericin B (0.5 to 0.8 mg/kg) was added to 400 mL, for cats, or to 500 mL, for dogs, of 0.45% saline containing 2.5% dextrose. These amounts were given subcutaneously 2 or 3 times weekly over several months, to a total cumulative dose of 8 to 26 mg/kg body weight. Subcutaneous infusions were generally well tolerated by the animals, although concentrations of amphotericin B in excess of 20 mg/L resulted in local irritation. This protocol enabled the administration of larger, and thus more effective, quantities of amphotericin B without producing marked azotaemia.     

A latex cryptococcal antigen agglutination test for diagnosis and monitoring of therapy for cryptococcosis

SUMMARY: A latex cryptococcal antigen agglutination test (LCAT) was performed on sera obtained during the first 14 days of treatment from 58 animals (46 cats, 9 dogs, 2 koalas and 1 long billed corella) with cryptococcosis. The same commercial kit was used for all samples, and most serum samples were treated with pronase before testing. Sera from all 58 cases tested positive with the qualitative LCAT protocol (using undiluted sera), while sera from all 26 cats without cryptococcosis tested negative. Titres determined using the quantitative protocol ranged from 1 to 131 072 (median titre between 2048 and 4096), with 57 of 58 cases (including all 8 animals that presented for neurological signs) having titres 2 and thus considered positive according to the manufacturer's recommendations. The LCAT titre was positively correlated with disease severity (r = 0.4169; P = 0.0011), and patients with disseminated skin and/or lymph node involvement had significantly higher titres than those that did not (P = 0.0157). The presence of neurological signs, the species of the patient, concurrent viral disease (in cats) and the biotype of the isolate had no significant association with the LCAT titre. Cats that died of active cryptococcosis despite treatment did not have significantly higher titres (P = 0.3010) than those that responded to treatment. Sequential LCAT determinations obtained in 37 patients during treatment provided a useful quantitative indication of clinical progress, although the decline in titre lagged somewhat behind clinical improvement. Generally, the antigen titre declined by 2 to 4 fold per month during successful therapy. Although there are insufficent data to make unequivocal recommendations, we suggest that either antifungal therapy be continued until the LCAT titre declines to less than 1, or therapy be discontinued after a 32 fold or greater reduction in titre, with periodic monitoring of the serum antigen titre. Treatment of serum samples with pronase substantially increased the sensitivity of the LCAT.     

Influence of temperature on the growth of Bordetella avium in turkeys and in vitro

Effects of temperature on growth of three strains of Bordetella avium were determined in young turkeys and in vitro. Colonization of the tracheal mucosa by two virulent strains of B. avium was significantly greater in cold-stressed turkeys than in heat-stressed turkeys. The avirulent vaccine strain, ART-VAX, colonized tracheas of cold-stressed turkeys to a limited extent but failed to colonize heat-stressed turkeys. Growth rates of the three B. avium strains were determined in brain-heart infusion broth at 30, 35, 40, and 45 C. All three strains grew best at 35 C but were killed by 45 C. Compared with virulent strains, ART-VAX grew markedly less at all temperatures, and most cultures of ART-VAX grew at 40 C only after a variable period of declining numbers of viable bacteria. This study indicates that temperature affects growth of B. avium in vivo and in vitro and that growth of the ART-VAX strain is fundamentally different from growth of virulent strains.     

The pathogenesis and treatment of osteomyelitis and laminitis in a stallion after the prolonged topical application of formalin to the distal phalanx

A 12-year-old Quarterhorse stallion was presented with a severe lameness in the left forefoot. There was a 3 cm diameter cavity in the sole that extended to the solar surface of the distal phalanx. Radiographs revealed an osteomyelitis and a sequestrum which probably developed following the prolonged topical application of 10 percent formalin. The sequestrum was removed and the infected bone curetted under general anaesthesia. The horse was shod with heart bar shoes on both front feet 7 days after the surgery. Eight months later, radiographs showed marked rotation of the distal phalanx despite continual shoeing with heart bar shoes. Surgical resection of the dorsal wall of the hoof at the toe removed the pressure applied by the laminar wedge, and combined with the stabilising and supporting action of the heart bar shoe, permitted realignment of the distal phalanx approximately 30 degrees closer to the normal skeletal axis by 26 days post-operatively. This case highlights some of the recent developments in the treatment of laminitis and suggests that effective treatment is possible if the value of the animal warrants the time and investment.     

Surgical management of an abdominal abscess in a Malayan tapir

A captive Malayan tapir was observed to have inappetence, weight loss, signs of depression, mild dehydration and diar rhoea. Haematological and serum biochemical tests showed anaemia, hypoproteinaemia, hyperfibrinogenaemia and neu-trophilia with a left shift. Ultrasonic examination of the abdomen under anaesthesia revealed a well-encapsulated abscess. The abscess was marsupialised to the ventral body wall. Culture of the pus produced a mixed bacterial growth. Antimicrobial therapy was based on bacterial sensitivity results. Follow-up ultrasonic examinations showed resolution of the abscess. Ninety-one days after surgery the tapir began regurgitating food and water. An abscess originating from the stomach and occluding the lumen of the duodenum was identified at surgery. The abscess ruptured during surgical manipulations and the tapir was euthanased.     

Antibiotics for the preservation of koala (Phascolarctos cinereus) semen

Aim To determine the normal microbial flora of the koala ejaculate and prepuce in order to select appropriate antibiotics for addition into diluents designed for the preservation of semen.
Procedure Bacteriological samples of the koala prepuce (n = 12) and ejaculate (n = 20) were submitted for microbial culture and sensitivity testing. Microbial flora of ejaculates collected by electroejaculation and artificial vagina were compared. The effects of varying concentrations of penicillin G and gentamicin on sperm motility and on the growth of bacteria in diluted semen stored at room temperature and 16°C over a 24 h period were investigated.
Results A range of bacteria was isolated from the koala prepuce and ejaculate. The predominant organisms in semen collected by electroejaculation and artificial vagina were Corynebacterium spp, none of which could be assigned to any recognised species. The addition of penicillin G and gentamicin to a PBS-based diluent at dose rates of 1000 to 2000 IU/mL and 100 to 200 m g/mL respectively, resulted in no adverse effect on sperm motility over a 24 h incubation period. Penicillin G (1000 IU/mL) and gentamicin (100 m g/mL) prevented growth of bacterial contaminants in diluted koala semen.
Conclusion By controlling the growth of bacteria in extended koala semen, penicillin G and gentamicin are likely to lengthen the period by which spermatozoa can be stored at 16°C and reduce the possibility of disease transmission during artificial insemination procedures.     

Colonization of the small intestine of weaned pigs by enterotoxigenic Escherichia coli that lack known colonization factors.

Intestinal colonization of 3-week-old weaned pigs by enterotoxigenic Escherichia coli (ETEC) strains that were originally isolated from weaned pigs with fatal diarrhea and that lacked K88, K99, F41, and 987P adhesins (4P- ETEC) was studied by histologic, immunofluorescent, and electron microscopic techniques. In the first experiment, 16 principal pigs were inoculated orogastrically with ETEC strain 2134 (serogroup O157: H19) or 2171 (serogroup 0141:H4), and eight control pigs were not inoculated. In the second experiment, 24 principals were inoculated with ETEC strain 2134, and 12 controls were inoculated with a nonenterotoxigenic strain of E. coli. Principal and control pigs were necropsied at intervals from 24 to 72 hours after inoculation of principals to provide the tissues used for this report. Results from the two experiments and with both ETEC strains were similar and therefore were combined. Adhesion by 4P- ETEC was demonstrated in ileum but not in cecum or colon in 22/40 principal pigs sampled at 24 to 72 hours after orogastric inoculation. Adherent bacteria were most apparent on the intestinal villi covering Peyer's patches. Only occasional adherent bacteria were detected in ileal sections from a few (4/20) of the control pigs. Adherence by 4P- ETEC was characterized by "patches" of bacteria closely associated with the lateral surfaces and less frequently with the tips and the bases of intact villi. In most cases, the adherent bacteria were separated from epithelial cell microvilli and other bacterial cells by a 50-400-nm space. Filamentous bacterial appendages bridged this space and formed a network among adjacent bacteria.(ABSTRACT TRUNCATED AT 250 WORDS)