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in Journal of the American Veterinary Medical Association

Abstract

OBJECTIVE

To identify antimicrobial susceptibility patterns for aerobic bacteria isolated from reptilian samples and, from those patterns, identify antimicrobials that could be considered for empirical treatment of reptiles with suspected bacterial infections.

SAMPLES

129 bacterial isolates from 61 of 127 samples from 96 reptiles.

PROCEDURES

Medical records of reptiles (chelonian, crocodilian, lizard, and snake) presented to the zoological medical service of a veterinary teaching hospital between January 2005 and December 2016 were reviewed for submissions of patient samples for aerobic bacterial culture and susceptibility testing. Sample type, presence or absence of bacterial growth, and antimicrobial susceptibilities of isolated bacteria were recorded. The isolation frequency and the antimicrobial susceptibilities of bacterial genera and species were tabulated.

RESULTS

Pseudomonas spp and Enterococcus spp were the most frequently isolated gram-negative and gram-positive bacteria, respectively. Isolates of gram-negative bacteria frequently had susceptibility to amikacin (86%), gentamicin (95%), tobramycin (92%), and trimethoprim-sulfamethoxazole (83%), and gram-positive bacteria frequently had susceptibility to ampicillin (83%), chloramphenicol (92%), doxycycline (100%), and gentamicin (100%). Isolates of gram-positive bacteria were consistently resistant to ceftazidime.

CONCLUSIONS AND CLINICAL RELEVANCE

Aerobic bacterial culture and antimicrobial susceptibility results for reptilian samples in this population indicated that aminoglycosides and trimethoprim-sulfamethoxazole or ampicillin and doxycycline could be considered as options for the empirical treatment of reptiles with infections caused by gram-negative or gram-positive bacteria, respectively.

Full access
in Journal of the American Veterinary Medical Association
in Journal of the American Veterinary Medical Association
in Journal of the American Veterinary Medical Association
in Journal of the American Veterinary Medical Association

Abstract

Case Description—A 5-year-old 38.3-kg (84.5-lb) mixed-breed dog was examined because of acute onset of lethargy and anorexia. Four days later, a raised, firm, warm 15 × 10-cm lesion was detected in the right caudal paralumbar area.

Clinical Findings—Cephalexin treatment yielded a poor response. Formalin-fixed tissue and fluid samples from the cystic areas of the lesion were submitted for cytologic and histologic examinations, routine bacterial and mycobacterial culture, and genus identification and 16S partial sequencing via PCR assays. Cytologic examination revealed chronic pyogranulomatous inflammation. Histologic examination by use of routine, Giemsa, silver, acid-fast, and modified acid-fast stains revealed multifocal nodular granulomatous panniculitis without identifiable organisms. Mycobacteria were initially identified via PCR assay and mycobacterial culture within 3 days. Mycobaterium goodii was speciated by use of partial 16S RNA sequence analysis.

Treatment and Outcome—The lesion resolved after long-term treatment with a combination of rifampin and clarithromycin and insertion of a Penrose drain. There has been no recurrence of the condition.

Clinical Relevance— M goodii is an environmental rapidly growing mycobacterium and is a zoonotic pathogen. Infections have not been previously reported in domestic animals in North America, although there are rare reports of infection in humans associated with surgery, especially surgical implants. Domestic animals are a potential sentinel for this non-tuberculous mycobacterial infection in humans, although lack of speciation in infections of domestic animals likely underestimates the potential public health importance of this pathogenic organism. Current microbiological molecular methods allow for a rapid and inexpensive diagnosis.

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in Journal of the American Veterinary Medical Association

Abstract

OBJECTIVE To describe the torsional and axial compressive properties of tibiotarsal bones of red-tailed hawks (Buteo jamaicensis).

SAMPLE 16 cadaveric tibiotarsal bones from 8 red-tailed hawks.

PROCEDURES 1 tibiotarsal bone from each bird was randomly assigned to be tested in torsion, and the contralateral bone was tested in axial compression. Intact bones were monotonically loaded in either torsion (n = 8) or axial compression (8) to failure. Mechanical variables were derived from load-deformation curves. Fracture configurations were described. Effects of sex, limb side, and bone dimensions on mechanical properties were assessed with a mixed-model ANOVA. Correlations between equivalent torsional and compressive properties were determined.

RESULTS Limb side and bone dimensions were not associated with any mechanical property. During compression tests, mean ultimate cumulative energy and postyield energy for female bones were significantly greater than those for male bones. All 8 bones developed a spiral diaphyseal fracture and a metaphyseal fissure or fracture during torsional tests. During compression tests, all bones developed a crushed metaphysis and a fissure or comminuted fracture of the diaphysis. Positive correlations were apparent between most yield and ultimate torsional and compressive properties.

CONCLUSIONS AND CLINICAL RELEVANCE The torsional and axial compressive properties of tibiotarsal bones described in this study can be used as a reference for investigations into fixation methods for tibiotarsal fractures in red-tailed hawks. Although the comminuted and spiral diaphyseal fractures induced in this study were consistent with those observed in clinical practice, the metaphyseal disruption observed was not and warrants further research.

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in American Journal of Veterinary Research

Abstract

Objective—To determine whether an inactivated culture of a microcin-producing avian Escherichia coli was capable of killing Salmonella isolates from reptiles in an in vitro test system.

Sample Population—57 Salmonella isolate from reptiles.

Procedure—A wild-type avian E coli electrotransformed with a plasmid coding for the production of microcin 24 was tested in an in vitro microassay system for its ability to kill 57 Salmonella spp isolated from reptiles. The reptile population included snakes, iguana, frilled lizards, turtles, other lizards, and unspecified reptiles.

Results—44 of the Salmonella isolates were inhibited strongly, compared with the in vitro assay controls; 12 had weak inhibition, and 1 was not inhibited by the microcin-producing E coli. Thirteen of the 57 isolates had resistance to at least 1 antibiotic, primarily streptomycin. There were 9 O serogroups identified in the 57 isolates, with serogroup H being the most prevalent (18 to 57).

Conclusion and Clinical Relevance—Antibiotics are not recommended to eliminate Salmonella organisms from reptiles because of the development of antibiotic resistance. Further studies are necessary to determine whether the use of microcin-producing bacteria will be effective in controlling Salmonella infections in companion reptiles. (Am J Vet Res 2001;62:1399–1401)

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in American Journal of Veterinary Research

Abstract

Objective—To determine whether a novel third-generation chelating agent (8mM disodium EDTA dehydrate and 20mM 2-amino-2-hydroxymethyl-1, 3-propanediol) would act as an antimicrobial potentiator to enhance in vitro activity of antifungal medications against fungal isolates obtained from horses with mycotic keratitis.

Sample Population—Fungal isolates (3 Aspergillus isolates, 5 Fusarium isolates, 1 Penicillium isolate, 1 Cladosporium isolate, and 1 Curvularia isolate) obtained from horses with mycotic keratitis and 2 quality-control strains obtained from the American Type Culture Collection (ATCC; Candida albicans ATCC 90028 and Paecilomyces variotii ATCC 36257).

Procedure—Minimum inhibitory concentrations (MICs) against fungal isolates for 4 antifungal drugs (miconazole, ketoconazole, itraconazole, and natamycin) were compared with MICs against fungal isolates for the combinations of each of the 4 antifungal drugs and the chelating agent. The Clinical and Laboratory Standards Institute microdilution assay method was performed by use of reference-grade antifungal powders against the fungal isolates and quality-control strains of fungi.

Results—Values for the MIC at which the antifungal drugs decreased the growth of an organism by 50% (MIC50) and 90% (MIC90) were decreased for the control strains and ophthalmic fungal isolates by 50% to 100% when the drugs were used in combination with the chelating agent at a concentration of up to 540 μg/mL.

Conclusions and Clinical Relevance—The chelating agent increased in vitro activity of antifungal drugs against common fungal pathogens isolated from eyes of horses with mycotic keratitis.

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in American Journal of Veterinary Research

Abstract

Objective—To determine the plasma pharmacokinetics of imipenem (5 mg/kg) after single-dose IV, IM, and SC administrations in dogs and assess the ability of plasma samples to inhibit the growth of Escherichia coli in vitro.

Animals—6 adult dogs.

Procedure—A 3-way crossover design was used. Plasma concentrations of imipenem were measured after IV, IM, and SC administration by use of high-performance liquid chromatography. An agar well antimicrobial assay was performed with 3 E coli isolates that included a reference strain and 2 multidrug-resistant clinical isolates.

Results—Plasma concentrations of imipenem remained above the reported minimum inhibitory concentration for E coli (0.06 to 0.25 µg/mL) for a minimum of 4 hours after IV, IM, and SC injections. Harmonic mean and pseudo-standard deviation halflife of imipenem was 0.80 ± 0.23, 0.92 ± 0.33, and 1.54 ± 1.02 hours after IV, IM, and SC administration, respectively. Maximum plasma concentrations (Cmax) of imipenem after IM and SC administration were 13.2 ± 4.06 and 8.8 ± 1.7 mg/L, respectively. Time elapsed from drug administration until Cmax was 0.50 ± 0.16 hours after IM and 0.83 ± 0.13 hours after SC injection. Growth of all 3 E coli isolates was inhibited in the agar well antimicrobial assay for 2 hours after imipenem administration by all routes.

Conclusions and Clinical Relevance—Imipenem is rapidly and completely absorbed from intramuscular and subcutaneous tissues and effectively inhibits in vitro growth of certain multidrug-resistant clinical isolates of E coli. (Am J Vet Res 2003;64:694–699)

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in American Journal of Veterinary Research