Pharmacokinetic indices for cefovecin after single-dose administration to adult sea otters (Enhydra lutris).

Seven sea otters received a single subcutaneous dose of cefovecin at 8 mg/kg body weight. Plasma samples were collected at predetermined time points and assayed for total cefovecin concentrations using ultra-performance liquid chromatography and tandem mass spectrometry. The mean (±SD) noncompartmental pharmacokinetic indices were as follows: CMax (obs) 70.6 ± 14.6 µg/mL, TMax (obs) 2.9 ± 1.5 h, elimination rate constant (kel ) 0.017 ± 0.002/h, elimination half-life (t1/2kel) 41.6 ± 4.7 h, area under the plasma concentration-vs.-time curve to last sample (AUClast) 3438.7 ± 437.7 h·µg/mL and AUC extrapolated to infinity (AUC0→∞ ) 3447.8 ± 439.0 h·µg/mL. The minimum inhibitory concentrations (MIC) for select isolates were determined and used to suggest possible dosing intervals of 10 days, 5 days, and 2.5 days for gram-positive, gram-negative, and Vibrio parahaemolyticus bacterial species, respectively. This study found a single subcutaneous dose of cefovecin sodium in sea otters to be clinically safe and a viable option for long-acting antimicrobial therapy.

Laser Capture Microdissection of Feline Streptomyces spp Pyogranulomatous Dermatitis and Cellulitis.

Suspected Streptomyces spp infections were identified in 4 cats at UC Davis Veterinary Medical Teaching Hospital between 1982 and 2011. Three had ulcerated, dark red mycetomas involving the dermis, subcutis, and fascia with fistulous tracts and/or regional lymphadenopathy. One cat had pyogranulomatous mesenteric lymphadenitis. Granulomatous inflammation in all cats contained colonies of Gram-positive, non-acid-fast organisms. All 4 cats failed to respond to aggressive medical and surgical treatment and were euthanized. Laser capture microdissection (LCM) was used to selectively harvest DNA from the affected formalin-fixed, paraffin-embedded (FFPE) tissues. Cloned amplicons from LCM-derived tissue confirmed the presence of Streptomyces spp in the dermatitis cases. Amplicons from the remaining cat with peritoneal involvement aligned with the 16S ribosomal RNA gene for Actinomycetales. Usually considered a contaminant, Streptomyces spp can be associated with refractory pyogranulomatous dermatitis and cellulitis in cats with outdoor access. LCM is useful in the diagnosis of bacterial diseases where contamination may be an issue.

Pharmacokinetics of ceftiofur crystalline free acid after single and multiple subcutaneous administrations in healthy alpacas (Vicugna pacos).

Six adult male alpacas received one subcutaneous administration of ceftiofur crystalline free acid (CCFA) at a dosage of 6.6 mg/kg. After a washout period, the same alpacas received three subcutaneous doses of 6.6 mg/kg CCFA at 5-day intervals. Blood samples collected from the jugular vein before and at multiple time points after each CCFA administration were assayed for ceftiofur- and desfuroylceftiofur-related metabolite concentrations using high-performance liquid chromatography. Pharmacokinetic disposition of CCFA was analyzed by a noncompartmental approach. Mean pharmacokinetic parameters (± SD) following single-dose administration of CCFA were Cmax (2.7 ± 0.9 µg/mL); Tmax (36 ± 0 h); area under the curve AUC0→∞ (199.2 ± 42.1 µg·h/mL); terminal phase rate constant λz (0.02 ± 0.003/h); and terminal phase rate constant half-life t1/2λz (44.7 h; harmonic). Mean terminal pharmacokinetic parameters (±SD) following three administrations of CCFA were Cmax (2.0 ± 0.4 µg/mL); Tmax (17.3 ± 16.3 h); AUC0→∞ (216.8 ± 84.5 µg·h/mL); λz (0.01 ± 0.003/h); and t1/2λz (65.9 h; harmonic). The terminal phase rate constant and the Tmax were significantly different between single and multiple administrations. Local reactions were noted in two alpacas following multiple CCFA administrations.

Prospective comparison of prostatic aspirate culture and cystocentesis urine culture for detection of bacterial infection in dogs with prostatic neoplasia.

OBJECTIVE: The purpose of this study was to determine whether prostatic aspirate culture is a superior method to detect infection compared to culture of urine collected by cystocentesis in dogs with prostatic neoplasia. MATERIALS AND METHODS: A prospective study was conducted and dogs with suspected or confirmed prostatic neoplasia were enrolled. Urinalysis was done and culture and antimicrobial susceptibility testing was performed on paired urine and prostatic aspirate samples collected at a single timepoint. RESULTS: Ten dogs with prostatic neoplasia were enrolled. All dogs had one or more clinical sign consistent with lower urinary tract disease. One dog (10%) had a positive urine culture, but negative prostatic aspirate culture, one dog (10%) had a positive prostatic aspirate culture, but negative urine culture, and one dog (10%) had both positive urine and prostatic aspirate cultures. Using prostatic aspirate culture as the reference standard, urine culture had a sensitivity for detecting infection of 87.5% (95% confidence interval 52.9 to 99.4) and specificity of 50% (92.6 to 97.4) in this population of dogs. CLINICAL SIGNIFICANCE: Positive cultures were uncommon with both culture collection methods. Study results did not identify prostatic aspirate culture to be a more sensitive method of detecting prostatic infection than urine culture collected by cystocentesis in these dogs with prostatic neoplasia.

Pharmacokinetic-pharmacodynamic integration of orbifloxacin in Japanese quail (Coturnix japonica) following oral and intravenous administration.

The pharmacokinetics of single-dose administration of orbifloxacin were determined in Japanese quail (Coturnix japonica) at dosages of 5 mg/kg intravenous (i.v. n = 12) and 7.5 mg/kg oral (p.o.; n = 5), 10 mg/kg p.o. (n = 5), 15 mg/kg p.o. (n = 12) and 20 mg/kg p.o. (n = 5) via HPLC. Orbifloxacin minimal inhibitory concentrations (MICs) against 22 microbial isolates from various bird species were performed to calculate pharmacodynamic surrogate markers. The concentration-time data were analyzed using a naïve pooled data (NPD) approach and compartmental and noncompartmental methods. Steady-state volume of distribution (Vd(ss)) and total body clearance (Cl) after i.v. administration were estimated to be 1.27 L/kg and 0.60 L/h·kg, respectively. Following 15 and 20 mg/kg p.o. dose, bioavailability was 102% and 117%, respectively. The harmonic mean of the corresponding terminal half-lives (T(1/2) λ(z) ) across all the dose groups was 1.71 h. The C(max) /MIC(90) and AUC(0∞24) /MIC(90) for the 15 and 20 mg/kg p.o. doses were ≥5.22 and ≥8.98, and ≥25.80 and ≥39.37 h, respectively. The results of this study suggest that 20 mg/kg orbifloxacin p.o. would be a rational daily dose to treat susceptible infections in Japanese quail not intended for food consumption. For more sensitive bacterial organisms, 15 mg/kg p.o. may also be effective.

Enterococcus infections in foals.

Enterococci have been increasing in prevalence in foal sepsis over the past three decades. There are no published studies in the peer-reviewed literature documenting common sites of infection, antimicrobial susceptibility, or outcome specifically associated with enterococcal infections in foals. Our objectives were to evaluate the sites of origin, antimicrobial susceptibility, and survival outcome to discharge in foals with enterococcal infections compared with foals with sepsis of another bacterial etiology. Seventy-five foals 0-30 days of age with cultures positive for Enterococcus and 170 control foals 0-30 days of age with cultures positive for other bacteria were included. Enterococcus was 2.67 times (95% confidence interval [CI], 1.49-4.80; P = 0.0012) more likely to be isolated from the lower urogenital tract of foals than were other bacteria. Enterococci were less likely to be isolated from blood cultures than other bacteria, with an odds ratio (OR) of 0.17 (95% CI 0.09-0.35; P < 0.0001). For Enterococcus isolates, 48% (n = 29/61) had a multiple antimicrobial resistance (MAR) index of ≥30% and 46% (n = 28/61) had a multiple drug resistance (MDR) index of ≥30%. Foals with enterococcal infections were less likely to survive to discharge (49.9% vs. 63.5%; P = 0.03). Enterococcus is commonly isolated from the lower urogenital tract of foals, is often multidrug resistant, and foals with enterococcal infections were less likely to survive. Multidrug resistance is common among enterococcal isolates, and therefore antimicrobial susceptibility testing of cultured isolates is warranted.

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.

Clinicopathologic and diagnostic imaging characteristics of systemic aspergillosis in 30 dogs.

BACKGROUND: Systemic aspergillosis is a serious disease of dogs for which the clinical characteristics are poorly described. OBJECTIVE: To describe the clinical and diagnostic imaging characteristics of dogs with systemic aspergillosis. ANIMALS: Thirty dogs with systemic aspergillosis. METHODS: Retrospective case review. Medical records were reviewed for signalment, clinical features, and results of clinicopathologic testing and diagnostic imaging. Diagnosis was confirmed by culture of Aspergillus terreus (n = 13), Aspergillus deflectus (n = 11), or other Aspergillus spp. (n = 6). RESULTS: Compared with the background hospital population, German Shepherd dogs and female dogs were overrepresented (odds ratio [OR] 43, 95% confidence interval [CI] 20-91, P < .0001, and OR 2.9, 95% CI 1.2-6.7, P= .02), respectively, with 20 of the 30 dogs being German Shepherd dogs and 77% (23 of 30) of the dogs being female. The median age was 4.5 years (range 2-8 years). Anemia, leukocytosis, hyperglobulinemia, azotemia, hypercalcemia, and hypoalbuminemia were present in 8, 21, 12, 9, 8, and 6 dogs, respectively. Diskospondylitis, osteomyelitis and thoracic lymphadenomegaly were present in 16, 10, and 5 dogs, respectively. Sonographic findings were enlarged hypoechoic lymph nodes (n = 12), mottled and irregular kidneys with or without masses (n = 12), pyelectasia, and an aggregate of echogenic material in the renal pelvis (n = 9). Thirteen dogs were treated with antifungal drugs, with survival times ranging from 0 to 25 months after diagnosis. CONCLUSIONS AND CLINICAL IMPORTANCE: Systemic aspergillosis typically involves young to middle-age female German Shepherd dogs, and there are characteristic abdominal ultrasound findings with the disease process. Infection with A. deflectus was as common as A. terreus, and in rare cases, long-term survival was associated with antifungal therapy.

Use of quantitative real-time PCR to determine viability of Streptococcus equi subspecies equi in respiratory secretions from horses with strangles.

BACKGROUND: In recent years, molecular approaches have been able to characterise the viability of equine upper respiratory tract pathogens using absolute molecular quantitation as well as detection of transcripts for virulence genes. OBJECTIVES: The objective of this study was to investigate molecular surrogates for S. equi subspecies equi (S. equi) viability in biological samples from horses with strangles. STUDY DESIGN: Retrospective cross-sectional study. METHODS: S. equi culture-positive and culture-negative upper airway secretions were assessed by qPCR at the genomic (gDNA) and complimentary DNA (cDNA) level for various target genes (SeM, SEQ2190, eqbE and szpSe). Absolute quantitation was performed using standard curves, and the results were expressed as number of S. equi target genes per µl of gDNA or cDNA. Additionally, the presence or absence of S. equi gene expression for the various target genes was assessed and compared with the culture results. RESULTS: While all 21 culture-positive samples tested S. equiqPCR positive, up to 43.7 and 18.9% of 64 culture-negative samples tested qPCR positive at the gDNA and cDNA level, respectively. Significant differences in absolute quantitation for S. equi at the gDNA level were found between culture-positive and culture-negative samples. When absolute quantitation of S. equi target genes at the gDNA level was assessed with the presence or absence of transcripts, there was a significantly higher S. equi target gene number in samples with expression of transcripts compared with samples with no expression of transcripts. MAIN LIMITATIONS: The lack of standardisation of samples collected in the field and the delay from sample collection to samples processing may have negatively affected the cultivability of S. equi and mRNA quality. CONCLUSIONS: Molecular viability for S. equi can be investigated by determining absolute quantitation and/or by detecting mRNA for specific target genes. However, veterinarians have to be cautioned that any qPCR-positive result for S. equi needs to be taken seriously and trigger biosecurity protocols aimed at reducing spread.

Evaluation of the Live Biotherapeutic Product, Asymptomatic Bacteriuria Escherichia coli 2-12, in Healthy Dogs and Dogs with Clinical Recurrent UTI.

BACKGROUND: Antimicrobial resistance is an emerging problem. HYPOTHESIS/OBJECTIVE: To investigate the safety and efficacy of a live biotherapeutic product, ASB E. coli 2-12 for UTI treatment. ANIMALS: Six healthy research dogs; nine client-owned dogs with recurrent UTI. METHODS: Prospective noncontrolled clinical trial. For safety data, research dogs were sedated, a urinary catheter was inserted into the bladder; 1010 CFU/mL of ASB E. coli 2-12 was instilled. Urine was cultured on days 1, 3, and 8 post-instillation and dogs were observed for lower urinary tract signs (LUTS). For client-owned dogs, ASB E. coli 2-12 was instilled similarly and urine cultures analyzed on days 1, 7, and 14 days postinstillation. RESULTS: No LUTS were noted in any of the 6 research dogs after ASB E. coli 2-12 infusion. Pulse field gel electrophoresis (PFGE) studies confirmed the bacterial strains isolated matched that ASB E. coli 2-12 strain. Four of the nine client-owned dogs had complete or nearly complete clinical cures by day 14. Of these four dogs, 3 also had microbiologic cures at day 14; one of these dogs had subclinical bacteriuria (in addition to ASB E. coli 2-12). Three of these four dogs had ASB E. coli 2-12 isolated from their urine at day 14. With the exception of mild, temporary, self-limiting, hyporexia in two dogs on the day of biotherapeutic administration, there were no major adverse effects. CONCLUSIONS AND CLINICAL IMPORTANCE: These results suggest ASB E. coli 2-12 is safe and should be investigated in a larger controlled study evaluating clinical UTI in dogs.

Bronchoscopy, Imaging, and Concurrent Diseases in Dogs with Bronchiectasis: (2003-2014).

BACKGROUND: Bronchiectasis is a permanent and debilitating sequel to chronic or severe airway injury, however, diseases associated with this condition are poorly defined. OBJECTIVE: To evaluate results of diagnostic tests used to document bronchiectasis and to characterize underlying or concurrent disease processes. ANIMALS: Eighty-six dogs that had bronchoscopy performed and a diagnosis of bronchiectasis. METHODS: Retrospective case series. Radiographs, computed tomography, and bronchoscopic findings were evaluated for features of bronchiectasis. Clinical diagnoses of pneumonia (aspiration, interstitial, foreign body, other), eosinophilic bronchopneumopathy (EBP), and inflammatory airway disease (IAD) were made based on results of history, physical examination, and diagnostic testing, including bronchoalveolar lavage fluid analysis and microbiology. RESULTS: Bronchiectasis was diagnosed in 14% of dogs (86/621) that had bronchoscopy performed. Dogs ranged in age from 0.5 to 14 years with duration of signs from 3 days to 10 years. Bronchiectasis was documented during bronchoscopy in 79/86 dogs (92%), thoracic radiology in 50/83 dogs (60%), and CT in 34/34 dogs (100%). Concurrent airway collapse was detected during bronchoscopy in 50/86 dogs (58%), and focal or multifocal mucus plugging of segmental or subsegmental bronchi was found in 41/86 dogs (48%). Final diagnoses included pneumonia (45/86 dogs, 52%), EBP (10/86 dogs, 12%) and IAD (31/86 dogs, 36%). Bacteria were isolated in 24/86 cases (28%), with Streptococcus spp, Pasteurella spp, enteric organisms, and Stenotrophomonas isolated most frequently. CONCLUSIONS AND CLINICAL IMPORTANCE: Bronchiectasis can be anticipated in dogs with infectious or inflammatory respiratory disease. Advanced imaging and bronchoscopy are useful in making the diagnosis and identifying concurrent respiratory disease.

Pneumonia Caused by Klebsiella spp. in 46 Horses.

BACKGROUND: Klebsiella spp. are implicated as a common cause of bacterial pneumonia in horses, but few reports describe clinical presentation and disease progression. HYPOTHESIS/OBJECTIVES: To describe the signalment, clinicopathologic data, radiographic and ultrasonographic findings, antimicrobial susceptibility, outcome, and pathologic lesions associated with Klebsiella spp. pneumonia in horses. ANIMALS: Forty-six horses from which Klebsiella spp. was isolated from the lower respiratory tract. METHODS: Retrospective study. Medical records from 1993 to 2013 at the William R. Pritchard Veterinary Medical Teaching Hospital, University of California, Davis were reviewed. Exact logistic regression was performed to determine if any variables were associated with survival to hospital discharge. RESULTS: Survival in horses <1 year old was 73%. Overall survival in adults was 63%. For adults in which Klebsiella pneumoniae was the primary isolate, survival was 52%. Mechanical ventilation preceded development of pneumonia in 11 horses. Complications occurred in 25/46 horses, with thrombophlebitis and laminitis occurring most frequently. Multi-drug resistance was found in 47% of bacterial isolates. Variables that significantly impacted survival included hemorrhagic nasal discharge, laminitis, and thoracic radiographs with a sharp demarcation between marked caudal pulmonary alveolar infiltration and more normal-appearing caudodorsal lung. CONCLUSIONS AND CLINICAL IMPORTANCE: Klebsiella spp. should be considered as a differential diagnosis for horses presenting with hemorrhagic pneumonia and for horses developing pneumonia after mechanical ventilation. Multi-drug resistance is common. Prognosis for survival generally is fair, but is guarded for adult horses in which K. pneumoniae is isolated as the primary organism.

Minimum inhibitory concentrations of equine Corynebacterium pseudotuberculosis isolates (1996-2012).

BACKGROUND: Few studies report the minimum inhibitory concentrations for antimicrobials against equine Corynebacterium pseudotuberculosis isolates. HYPOTHESIS/OBJECTIVES: To evaluate trends in the in vitro activities of 20 antimicrobials against equine Corynebacterium pseudotuberculosis isolates from 1996 to 2012 and to determine if a relationship exists between the minimum inhibitory concentration (MIC) and location of the abscess. ANIMALS: Corynebacterium pseudotuberculosis isolates from 196 horses with naturally occurring disease. METHODS: Retrospective and cross-sectional design. Medical records were reviewed to obtain clinical and MIC data. Minimum inhibitory concentrations were determined by the microdilution technique. The MIC results over 3 periods were compared (1996-2001, 2002-2006, 2007-2012). RESULTS: The MIC90 values for clinically relevant antimicrobials were as follows: chloramphenicol ≤ 4 µg/mL, enrofloxacin ≤ 0.25 µg/mL, gentamicin ≤ 1 µg/mL, penicillin =0.25 µg/mL, rifampin ≤ 1 µg/mL, tetracycline ≤ 2 µg/mL, trimethoprim-sulfamethoxazole (TMS) ≤ 0.5 µg/mL, ceftiofur =2 µg/mL, and doxycycline ≤ 2 µg/mL. There were no significant changes in MIC results over the study period. There was no relationship between MIC patterns and abscess location. CONCLUSIONS AND CLINICAL IMPORTANCE: The MIC50 and MIC90 values of antimicrobials evaluated in this study for equine isolates of C. pseudotuberculosis did not vary over time. Abscess location was not associated with different MIC patterns in cultured isolates. Several commonly used antimicrobials are active in vitro against C. pseudotuberculosis in vitro.

Bacterial urinary tract infections associated with transitional cell carcinoma in dogs.

BACKGROUND: Urinary tract infections (UTI) are believed to be common in dogs with transitional cell carcinoma (TCC), but incidence and contributing factors have not been reported. OBJECTIVES: To determine the frequency and bacterial agents associated with UTI in dogs with TCC and define contributing factors. ANIMALS: Eighty-five dogs with a history of urogenital TCC undergoing treatment with chemotherapy that had at least 1 urine culture performed. METHODS: Medical records and culture results were retrospectively reviewed and ultrasound images were reviewed when available. Clinical factors were evaluated statistically for association with positive culture. RESULTS: Fifty-five percent (47/85) of dogs had at least 1 positive culture during the course of treatment. Female dogs (80%, 40/50) were more likely than male dogs (29%, 10/35) to have at least 1 positive culture. Ultrasound examination determined that female dogs were more likely to have urethral (74%, 31/42) or trigonal tumor involvement (71%, 30/42) compared to male dogs (32%, 9/28 and 43%, 12/28, respectively). The most commonly isolated organisms were Staphylococcus spp. (23.9%, 29/121) and Escherichia coli (19.8%, 24/121). Dogs with urethral involvement of TCC were significantly more likely to have at least 1 positive culture than dogs without urethral involvement (75%, 30/40 versus 30%, 9/30). CONCLUSIONS: Urinary tract infection is common in dogs with TCC highlighting the importance of regular monitoring for bacterial cystitis in dogs with TCC. In addition, clinical factors such as tumor location and sex may be predictive of positive culture and can help clinicians assess the risk of UTI.

The Establishment of the Colombian Integrated Program for Antimicrobial Resistance Surveillance (COIPARS): A Pilot Project on Poultry Farms, Slaughterhouses and Retail Market.

The development of antimicrobial resistance among bacteria (AMR) is currently one of the world's most pressing public health problems. The use of antimicrobial agents in humans and animals has resulted in AMR which has narrowed the potential use of antibiotics for the treatment of infections in humans. To monitor AMR and to develop control measures, some countries, such as the USA, Canada and Denmark, have established national integrated surveillance systems (FDA, , CIPARS, 2007, DANMAP,2002). The components of these programs monitor changes in susceptibility/resistance to antimicrobial agents of selected zoonotic pathogens and commensal organisms recovered from animals, retail meats and humans. The rapid development of Colombia's animal production industry has raised food safety issues including the emergence of antibiotic resistance. The Colombian Integrated Surveillance Program for Antimicrobial Resistance (COIPARS) was established as a pilot project to monitor AMR on poultry farms, slaughter houses and retail markets.

Immunity to Rhodococcus equi.

Rhodococcal pneumonia is an important, life threatening disease of foals and immunosuppressed humans. Increased knowledge of the mechanisms of protective immunity are required in order to develop an effective immunoprophylaxis strategy for horses and immunotherapeutic regiments for people. Both humoral and cellular components of the immune system may be involved in immune clearance of R. equi. The susceptibility of foals less than 4-6 months of age is postulated to reflect waning maternal antibody, and passive transfer of hyperimmune plasma can provide protection on endemic farms. However, effective clearance is likely to require appropriate cellular responses, including the secretion of cytokines. In murine models, both CD4+ and CD8+ T lymphocytes can reduce bacterial counts in the lung. CD4+ cells appear to be both required and sufficient, and IFN-gamma is a primary mediator. Clearance appears to be a type 1 immune response while type 2 responses may lead to a failure to clear and lesion development. It remains to be determined how the cellular immunity experiments reported in mice relate to horses and humans. Likewise, the role of specific R. equi antigens in protective immunity has not been determined.

Partial genome sequencing of Rhodococcus equi ATCC 33701.

Preliminary analysis of a partial (30% coverage) genome sequence of Rhodococcus equi has revealed a number of important features. The most notable was the extent of the homology of genes identified with those of Mycobacterium tuberculosis. The similarities in the proportion of genes devoted to fatty acid degradation and to lipid biosynthesis was a striking but not surprising finding given the relatedness of these organisms and their success as intracellular pathogens. The rapid recent improvement in understanding of virulence in M. tuberculosis and other pathogenic mycobacteria has identified a large number of genes of putative or proven importance in virulence, homologs of many of which were also identified in R. equi. Although R. equi appears to have currently unique genes, and has important differences, its similarity to M. tuberculosis supports the need to understand the basis of virulence in this organism. The partial genome sequence will be a resource for workers interested in R. equi until such time as a full genome sequence has been characterized.

Extensor tendon: anatomy, injury, and reconstruction.

Although seemingly simple in its anatomy and function, the extensor mechanism of the hand is actually a complex set of interlinked muscles, tendons, and ligaments. A thorough understanding of the extensor anatomy is required to understand the consequences of injury at various levels. Reconstructive options must restore normal function. Whereas primary repair of anatomic structures is frequently possible in acute injury, it is rarely possible in chronic situations. Technically exacting procedures may be necessary to restore function.

Ileocecal intussusception corrected by resection within the cecum in two horses.

Irreducible ileocecal intussusceptions pose a difficult surgical problem. Strangulating ileocecal intussusceptions involving the ileum and jejunum were identified in 2 horses undergoing exploratory laparotomy because of colic. Surgical correction in both horses was achieved by amputation of the ileocecal intussusception from within the cecal lumen, via typhlotomy. The inverted ileal stump was blindly stapled near the ileocecal orifice after pulling the intussusceptum into the cecum. A jejunocecostomy was performed to reestablish intestinal continuity.