Biomedical subjects

D J Schaeffer

Publications and source records attributed to D J Schaeffer.

At least 19 recordsLinked to original sources

PubMed2005

Reproducibility of a commercial in vitro allergen-specific assay for immunoglobulin E in dogs.

Samples of serum taken from 42 dogs with clinical signs and histories indicating pruritic skin disease and/or diseases of the ear were tested in a commercial allergen-specific assay for immunoglobulin E. Dogs which had been treated with glucocorticoids and/or antihistamines were not excluded. The samples were separated into two equal aliquots, given different randomised numbers, and analysed in two batches on two separate days. The laboratory was blinded to the identification numbers and the history of each dog, but knew the purpose of the study. The results for 48 allergens were expressed in modified absorbance units (MAU). The overall median MAU was 29. For each allergen the mean difference between the MAU values of the paired duplicates was determined and the difference was compared to zero by a paired t test. The number of means that were not 0 (P<0.05) in each allergen group were: seven of 10 grasses, seven of nine weeds, two of 13 trees, six of 10 fungi, and three of six environmental allergens. A single 2 x 2 table for the 48 allergens was created with MAU > or = 60 defined as 'positive' and < 60 as 'negative'. There were 116 of 188 (62 per cent) pairs that were reproducibly 'positive' and 1756 of 1828 (96 per cent) pairs that were reproducibly 'negative'.

Allergens↗

PubMed2005

Assessment of corticosteroid-induced alkaline phosphatase as a prognostic indicator in canine lymphoma.

OBJECTIVES: To examine the incidence of elevated corticosteroid-induced alkaline phosphatase (sALP) in dogs with lymphoma and to determine if sALP is a reliable prognostic indicator in canine lymphoma. METHODS: The medical records of 62 canine lymphoma patients treated with a combination chemotherapy protocol from 1994 to 2003 at the University of Illinois Veterinary Teaching Hospital were examined. Variables assessed with respect to response rate and remission duration included age, bodyweight, sex, breed, World Health Organization stage (I to V), substage (a or b), pretreatment administration of corticosteroid, and serum levels of alkaline phosphatase, sALP and alanine aminotransferase. RESULTS: sALP was not statistically significant with respect to response rate or duration of remission, nor was preinduction glucocorticoid administration. Stage was significant with respect to achieving remission. CLINICAL SIGNIFICANCE: It was found that sALP is not a useful prognostic indicator for response rate and remission duration in dogs with lymphoma.

Adrenal Cortex Hormones↗

PubMed2005

Short-term survival after surgery for epiploic foramen entrapment compared with other strangulating diseases of the small intestine in horses.

REASONS FOR PERFORMING STUDY: Epiploic foramen entrapment (EFE) is one of the more common causes of colic in horses, but recent reports suggest a poor prognosis after surgical treatment. HYPOTHESIS: That EFE has a good prognosis compared with other small intestinal strangulating lesions. METHODS: Surgical findings, surgical procedures and short-term outcome were recorded for 157 horses that underwent surgery for strangulating lesions of the small intestine at the University of Illinois from 1994 to 2003. Horses were assigned to 3 groups for comparison; those with EFE, strangulation by lipoma and miscellaneous strangulating lesions. A logistic regression model and Monte Carlo tests of the binomial proportions were used to examine survival rates. The Kruskal-Wallis test was used to determine differences in usage of surgical treatments. Measurements of length and viability indices were analysed using a one-way analysis of variance followed by Tukey's HSD test, and viability scores were analysed using an exact Kruskal-Wallis test. Significance was set at P < 0.05. RESULTS: Horses with EFE were significantly more likely to be discharged (95%) than those with the other conditions (P < 0.05). The proportion of horses with ileal involvement was greater in horses with EFE than in the other 2 groups (P < 0.05), although this did not affect outcome. The distributions of viability grades for EFE and lipoma differed significantly (P < 0.05). CONCLUSIONS: The prognosis for horses that had surgery at this hospital for EFE was better than for those with the other conditions, although the greater proportion of horses with EFE with ileal involvement could influence outcome. Therefore, surgeons must consider ways of improving jejunocaecostomy and determining when bowel is viable, the latter to avoid jejunocaecostomy.

Analysis of Variance↗

PubMed2005

The effect of axial and abaxial release on meniscal displacement in the dog.

The meniscal release (MR) is used to minimize meniscal pathology after Tibial Plateau Leveling Osteotomy (TPLO) surgery. The purposes of this study were: (i) to describe meniscal orientation in a unaltered cadaveric canine stifle, a cruciate deficient stifle, TPLO repaired stifle with and without the MR using magnetic resonance imaging; (ii) to determine if the abaxial release is equivalent to the axial release in its ability to affect caudal pole displacement in a TPLO repaired stifle and (iii) to evaluate with MRI the effect of MR on the femorotibiol articular cartilage contact area in a TPLO repaired stifle. Briefly, cadaver limbs were placed into a jig designed to mimic a weight-bearing stance at 140 degrees and 90 degrees at the stifle. The limbs were sequentially evaluated from the unaltered state; after cranial cruciate ligament transection; after TPLO stabilization; and finally after a meniscal release. No significant difference was found between the intrameniscal area (IMA) of the abaxial and axial meniscal releases although there was an increase in the IMA after the meniscal release compared to the IMA in the normal, cranial cruciate ligament deficient stifle, and TPLO stabilized stifle. In the abaxial release, a meniscal remnant remained in situ and provided a space effect between the femur and the tibial plateau. This is in contrast to the axial meniscal release, where the entire caudal pole of the medial meniscus relocated caudolaterally and consequently permitted more direct femorotibial contact. Overall, however, there was evidence of caudal pole compression of the medial meniscus throughout the MRI series which was ameliorated by either of the MR procedures.

Animals↗

PubMed2003

B-mode ultrasonographic evaluation of paired testicular diameter of mature boars in relation to average total sperm numbers.

Crossbred, meat-type terminal sire boars (n = 215) were randomly assigned by age group (240-300, 301-360, 361-420, 421-480, 481-540, 541-600, and >721 days). Stud boars were on a once or twice weekly semen collection schedule. Testis diameters, in duplicate, were obtained using B-mode ultrasonography. Summation of average left and right testis diameter within boar gave the paired testicular diameter (PTD). Average ejaculate volume, sperm concentration (sperm/ml), and total sperm numbers for each boar were determined using composite data (average values) obtained from the last four semen collections. There was a <0.5cm difference between left and right testis diameters, with the left testis being the larger of the two testes (P = 0.03). There was no difference in PTD found between age groups in this study. Conversely, a dramatic increase in average total sperm numbers (ATSN) was observed between boars of 240-300 days (57.0+/-27.4 x 10(9) sperm) and up to 420 days (118.6+/-33.6 x 10(9) sperm) of age. The ATSN (127+/-32.5 x 10(9) sperm) remained constant for the 421-480 to >721-day age groups. The correlation between PTD and ATSN was low (r = 0.24) in this study. The results of this study demonstrate that normal boars should exhibit <0.5cm diameter difference between testes. As observed in other studies, the left testis was usually larger than the right testis. Correlation of total sperm numbers in a boar ejaculate using a composite ejaculate score (average values) and PTD measurements obtained using B-mode ultrasonography was poor when used in boars >8 months of age.

Aging↗

PubMed2001

Age distributions of horses with strangulation of the small intestine by a lipoma or in the epiploic foramen: 46 cases (1994-2000).

OBJECTIVE: To test the hypothesis that strangulation of the small intestine by a lipoma or in the epiploic foramen is more common in older horses. DESIGN: Retrospective study. ANIMALS: 46 horses. PROCEDURE: Ages of horses with strangulation of the small intestine by a lipoma (n = 29) or in the epiploic foramen (17) were compared with ages of 79 horses with miscellaneous small intestinal lesions. Effects of increasing age on risk of the diseases of interest were examined by use of logistic regression and a 1-sided trend test for binomial proportions. RESULTS: Mean age of the horses with strangulation in the epiploic foramen (9.6 years) was the same as that for the horses with miscellaneous small intestinal lesions (7.7), but mean age of the horses with strangulation by a lipoma (19.2) was significantly greater than that for the other groups. The proportion of horses with lipoma increased significantly with increasing age, but the proportion with strangulation in the epiploic foramen did not. CONCLUSIONS AND CLINICAL RELEVANCE: Results refute the current suggestion that increasing age predisposes horses for strangulation of the small intestine in the epiploic foramen but support the suggestion that the risk of strangulation of the small intestine by a lipoma increases with age.

Age Distribution↗

PubMed2001

Superthreshold behavior of ultrasound-induced lung hemorrhage in adult mice and rats: role of pulse repetition frequency and exposure duration.

Superthreshold behavior for ultrasound-induced lung hemorrhage was investigated in adult mice and rats at an ultrasound center frequency of 2.8 MHz to assess the role of pulse repetition frequency and exposure duration. One hundred fifty, 6-7-week-old female ICR mice and 150 10-11-week-old female Sprague-Dawley rats were each divided into 15 exposure groups (10 animals per group) for a 3 x 5 factorial design (3 exposure durations of 5, 10, and 20 s and 5 pulse repetition frequencies of 25, 50, 100, 250, and 500 Hz). The in situ (at the pleural surface) peak rarefactional pressure of 12.3 MPa and the pulse duration of 1.42 micros were the same for all ultrasonically-exposed animals. In addition, 15 sham exposed mice and 15 sham exposed rats were included into both studies. In each study of 165 animals, the exposure conditions were randomized. The lesion depth and surface area were measured for each animal, as well as the percentage of animals with lesions per group. The characteristics of the lesions produced in mice and rats were similar to those described in studies by our research group and others, suggesting a common pathogenesis for the initiation and propagation of the lesions at the gross and microscopic levels. The proportion of lesions in both species was related statistically to pulse repetition frequency (PRF) and exposure duration (ED), with the exception that PRF in rats was not quite significant; the PRF x ED interaction (number of pulses) for lesion production was not significant for either species. The PRF, but not ED, significantly affected lesion depth in both species; the PRF x ED interaction for depth was not significant for either species. Both PRF and ED significantly affected lesion surface area in mice, while neither affected area in rats; the PRF x ED interaction for surface area was not significant for either species.

Analysis of Variance↗

PubMed2000

Microcystin-LR decreases hepatic and renal perfusion, and causes circulatory shock, severe hypoglycemia, and terminal hyperkalemia in intravascularly dosed swine.

Cross-bred, anesthetized female swine were given intravascularly a lethal (72 microg/kg; n = 6) or toxic-sublethal (25 microg/kg; n = 6) dose of microcystin-LR (MCLR), from Microcystis aeruginosa, or the vehicle (n = 4). At the high dose, from 12 to 18 min after administration, central venous pressure and hepatic perfusion were significantly lower, and shortly thereafter, portal venous pressure was significantly higher and aortic mean pressure was significantly lower than controls. By 45 min postdosing, serum bile acids, lactate, potassium, and total bilirubin, as well as blood pO2, were significantly higher, while hematocrit, platelet count, and blood bicarbonate, pCO2, and base excess were significantly lower than controls. By 90 min, serum arginase, urea nitrogen, inorganic phosphorus, and creatinine were significantly higher, while glucose and blood pH were significantly lower than in controls. By 150 min, serum alanine and aspartate aminotransferases, alkaline phosphatase, lactate dehydrogenase, and creatinine phosphokinase activities were significantly higher than controls. At the low dose, significant differences from controls occurred in hemodynamic, organ perfusion, and serum chemistry parameters, but such changes generally took longer to occur and were of a lesser magnitude than at the high dose. Livers of the high-dose swine were swollen and dark red-purple, and exuded excessive blood on the cut surface. Based on increases in liver weight and liver hemoglobin, 38% of the total blood volume was lost into the liver. Terminally, all high-dose swine experienced hyperkalemia, and most had severe hypoglycemia. Death due to acute MCLR toxicosis in intravascularly dosed swine appears to result from severe intrahepatic hemorrhage, partial obstruction of blood flow through the liver, circulatory shock, severe hypoglycemia, and/or terminal hyperkalemia.

Animals↗

PubMed2000

Anti-HIV activity of extracts and compounds from algae and cyanobacteria.

The human immunodeficiency virus (HIV) is the retrovirus that causes the acquired immune deficiency disease syndrome (AIDS). This review discusses the anti-HIV activity of extracts and compounds isolated from freshwater and marine algae, and cyanobacteria (formerly called "blue-green algae"). Compounds and extracts with anti-HIV activity are also active against other retroviruses such as herpes simplex virus (HSV), but the amount of antiviral activity varies with the compound and the virus. Most of the research has focused on sulfated homopolysaccharides and heteropolysaccharides. Sulfoglycolipids, carrageenans, fucoidan, sesquiterpene hydroquinones, and other classes of compounds with anti-HIV activity that have been isolated from algae have received less attention. Most studies have used in vitro test systems, but a few in vivo studies have been carried out using compounds isolated from algae or analogs produced synthetically or isolated from other natural sources. Sulfated homopolysaccharides are more potent than sulfated heteropolysaccharides. The presence of the sulfate group is necessary for anti-HIV activity, and potency increases with the degree of sulfation. Studies using nonsulfated and sulfated homo- and heteropolysaccharides isolated from algae or other natural sources, or synthesized, have revealed the mechanisms of binding of drugs to the virion, and the mechanisms of viral binding to host cells. However, given the few classes of compounds investigated, most of the pharmacopeia of compounds in algae and cyanobacteria with antiretroviral activity is probably not known.

Animals↗

PubMed2000

Short- and long-term survival and prevalence of postoperative ileus after small intestinal surgery in the horse.

The records of 74 horses that recovered from anaesthesia after surgery for a small intestinal lesion from 1994 to 1999 were reviewed. Sixty-three horses (85%) had a strangulating lesion and 43 of these (68%) had a resection and anastomosis. Four of 11 horses (36%) without a strangulating lesion had a resection and anastomosis. Sixty-three horses (85%) survived to discharge, with a survival rate of 53/63 in horses with a strangulating lesion (84%) and 10/11 (91%) in others. For all lesions, short-term survival for all end-to-end anastomoses (91%; 21/23) and for no resection (92%; 23/25) were superior (P < 0.05) to survival for jejunocaecal anastomosis (76%; 19/25). Fourteen horses (19%) had a repeat abdominal surgery during hospitalisation; 9 of these (64%) survived short-term. Postoperative ileus developed in 7/70 horses (10%) after surgery for a problem other than proximal enteritis, and all had a strangulating lesion. Postoperative ileus (POI) was more likely after a jejunocaecostomy than after other procedures, and did not develop after a jejunojejunostomy. Survival > 7 months was 52/69 (75%) and for > 12 months was 39/57 (68%). The estimated prevalence of adhesions was 13%. Short-term survival was poorest in horses that had a jejunocaecostomy, but long-term survival was less affected by the anastomosis used. The sharpest decline in survival was during the first postoperative week and postoperative mortality then declined over time after surgery. A postoperative protocol that allowed early postoperative feeding was well tolerated. The results confirm that the overall prognosis after small intestinal surgery in horses is improved over earlier findings.

Anastomosis, Surgical↗

PubMed2000

Evaluation of short-term increased intraocular pressure on flash- and pattern-generated electroretinograms of dogs.

OBJECTIVE: To determine the electrodiagnostic and histologic response of short-term increases of intraocular pressure (IOP) on transient pattern electroretinograms (PERG) and flash electroretinograms (FERG) in the eyes of dogs. ANIMALS: 8 healthy mixed-breed dogs. PROCEDURE: Transient PERG and FERG waveforms were recorded from dogs (while anesthetized) as IOP was increased from baseline (7 to 19 mm Hg) to 90 mm Hg. One hundred mean PERG responses and a single FERG response were recorded at each step during 3 recording sessions. Globes of each dog were enucleated after euthanasia on posttreatment day 7 and evaluated by a pathologist. RESULTS: Increases in spatial frequency resulted in decreased amplitudes of N2 (second negative PERG peak). Increases in IOP resulted in decreases in all 3 PERG waveforms and the FERG waveform. All values began to return to baseline after short-term increases in IOP on day 0, and waveforms were not significantly different on posttreatment days 3 and 7 CONCLUSIONS: Data suggest that short-term increases in IOP affect PERG and FERG waveforms, and PERG waveforms are more sensitive to increases in IOP Differences were not detected between treated and control eyes on histologic examination. Further studies are necessary to determine at what IOP permanent damage to ganglion and photoreceptor cells will develop and whether PERG is a reliable clinical diagnostic technique for use in dogs to reveal retinal damage that is secondary to increased IOP prior to changes in waveforms generated by FERG in dogs.

Animals↗

PubMed1999

Leukopenia in six healthy Belgian Tervuren.

A healthy 6.5-year-old sexually intact female Belgian Tervuren was found to be persistently leukopenic during preoperative evaluation for routine ovariohysterectomy. Abnormalities of the erythroid or myeloid series were not detected during bone marrow analysis. Blood samples for CBC were collected from 8 additional healthy Belgian Tervuren of both sexes and of various ages. Six of the 9 dogs were leukopenic, with WBC counts between 2.38 and 5.42 x 10(3) WBC/microl (mean +/- SD, 4.13 +/- 1.04 x 10(3) WBC/microl). Leukopenia was a persistent finding in the 3 dogs from which multiple blood samples were collected. All dogs were otherwise clinically normal. Leukopenia, as defined by a WBC count < 6.00 x 10(3) WBC/microl, may be a common finding in the Belgian Tervuren breed.

Animals↗

PubMed1999

Effect of perioperative prophylactic antimicrobial treatment in dogs undergoing elective orthopedic surgery.

OBJECTIVE: To determine whether perioperative antimicrobial prophylaxis would reduce incidence of postoperative infection among dogs undergoing elective orthopedic procedures. DESIGN: Randomized, controlled, blinded, intention clinical trial. ANIMALS: Dogs of any breed, sex, or age undergoing elective orthopedic surgery at a veterinary teaching hospital. PROCEDURES: Dogs were randomly assigned to 1 of 3 groups: treatment with saline solution, treatment with potassium penicillin G, and treatment with cefazolin. Treatments were intended to be administered within 30 minutes prior to surgery; a second dose was administered if surgery lasted > 90 minutes. Dogs were monitored for 10 to 14 days after surgery for evidence of infection. RESULTS: After the first 112 dogs were enrolled in the study, it was found that infection rate for control dogs (5/32 dogs) was significantly higher than the rate for dogs treated with antimicrobials (3/80 dogs). Therefore, no more dogs were enrolled in the study. A total of 126 dogs completed the study. Monte Carlo simulations indicated that compared with dogs that received antimicrobials prophylactically, dogs that received saline solution developed infections significantly more frequently. Difference in efficacy, however, was not observed between the 2 antimicrobial drugs used. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicated that perioperative antimicrobial prophylaxis decreased postoperative infection rate in dogs undergoing elective orthopedic surgery, compared with infection rate in control dogs. Cefazolin was not more efficacious than potassium penicillin G in these dogs.

Animals↗

PubMed1999

Use of corticosteroids for treating dogs with airway obstruction secondary to hilar lymphadenopathy caused by chronic histoplasmosis: 16 cases (1979-1997).

OBJECTIVE: To examine use of corticosteroids in treating dogs with airway obstruction secondary to hilar lymphadenopathy caused by chronic histoplasmosis. DESIGN: Retrospective study. ANIMALS: 16 dogs. PROCEDURE: Records for dogs with airway obstruction examined from January 1979 through December 1997 were reviewed. Dogs were included in the study if they had hilar lymphadenopathy documented radiographically and bronchoscopically, had serum antibodies against Histoplasma capsulatum, and did not have organisms in any cytologic or histologic samples. Dogs were assigned to groups on the basis of treatment given (5 dogs, corticosteroids only; 5 dogs, corticosteroids and antifungal medication; 6 dogs, antifungal medication only). RESULTS: Clinical signs resolved in < 1 week in dogs treated only with corticosteroids. In dogs treated with corticosteroids and an antifungal medication, improvement was evident in a mean of 2.6 weeks. In 5 of 6 dogs treated with only an antifungal medication, clinical signs resolved in a mean of 8.8 weeks. Dogs receiving corticosteroids did not develop active or disseminated histoplasmosis. CLINICAL IMPLICATIONS: Corticosteroids can be used successfully in the treatment of dogs with hilar lymphadenopathy secondary to histoplasmosis. Affected dogs must be carefully evaluated for active infection. Specimens obtained by means of bronchoalveolar lavage, tracheal washing, or other methods should be examined to exclude the possibility of an active infection, which could result in corticosteroid-induced dissemination of disease.

Adrenal Cortex Hormones↗

PubMed1999

Risk assessment of microcystin in dietary Aphanizomenon flos-aquae.

Aphanizomenon flos-aquae, a cyanobacterium that is marketed as a health food supplement, is harvested from natural blooms in Klamath Lake (Oregon) that are occasionally contaminated by Microcystis spp. Regulatory agencies in several countries are developing regulations to control the amount of microcystin in drinking water and other products, including products produced from A. flos-aquae. Regulation of microcystin (MC), a toxin produced by Microcystis spp. that is potentially present in natural culture of A. flos-aquae, should be based on studies in which a test species is exposed to the natural mixture of these cyanobacteria. A 1984 feeding trial to determine the effects of high dietary levels of A. flos-aquae on reproduction and development of mice is reanalyzed in light of recent analyses for microcystin-LR (MCLR) in the diets of those mice. Young adult mice consuming up to 333 microg MCLR/kg body weight (bw)/day exhibited no adverse effects on growth and reproduction, fetal development, and survival and organ weights of neonates. Based on a NOAEL of 333 microg MCLR/kg bw/day, a safety factor of 1000, consumption of 2 g/day of A. flos-aquae by a 60-kg adult, the safe level of MCLR as a contaminant of A. flos-aquae products is calculated to be 10.0 microg MCLR/g.

Animals↗

PubMed1999

Evaluation of activity of selected ophthalmic antimicrobial agents in combination against common ocular microorganisms.

OBJECTIVE: To determine in vitro efficacy of gentamicin, tobramycin, and miconazole when used in combination, with or without atropine, against Pseudomonas or Aspergillus sp. PROCEDURE: Selected ophthalmic agents were combined for predetermined times. Sterile disks impregnated with the combined solutions were prepared and placed on Mueller-Hinton plates that were seeded with Pseudomonas or Aspergillus sp. Zones of growth inhibition were measured at postincubation hours 24 and 48. RESULTS: Tobramycin alone inhibited growth of Pseudomonas sp, whereas miconazole inhibited growth of Aspergillus sp. Significant differences in zones of growth inhibition when atropine was combined with tobramycin, when gentamicin was combined with miconazole, or when atropine was combined with miconazole and gentamicin, were not detected. CLINICAL RELEVANCE: Combining selected ophthalmic therapeutic agents for as long as 6 hours does not appear to alter the in vitro efficacy of the agents against microorganisms used in this study.

Animals↗

PubMed1999

Thrombogenicity of polyethylene oxide-bonded Dacron sewing ring in a mechanical heart valve.

BACKGROUND AND AIM OF THE STUDY: The aim of the study was to evaluate the effect of binding hydrophilic polyethylene oxide (PEO) onto Dacron fibers in the sewing ring of a mechanical heart valve (MHV), in terms of thrombogenicity of the prosthesis. METHODS: The study was performed in blinded fashion. Six Yorkshire-cross pigs (bodyweight 35-45 kg) were implanted with MHVs, in the mitral annulus, with the PEO-treated sewing ring. An additional five pigs implanted with identical MHVs, but with untreated sewing rings, served as controls. PEO of chain-length 10,000 Da was grafted to Dacron fibers using gamma irradiation. PEO-bonded Dacron fibers (diameter 100 microns) were used to weave the sewing ring, which was then assembled on a titanium stent (OD 25 mm). Autologous platelets were labeled with 111In-tropolone and injected intravenously (850-1250 microCi per injection) into the pigs on removal from cardiopulmonary bypass (CPB). At 20-24 h after surgery, platelet thrombi adherent to MHV components, and shed emboli trapped in the brain, lung, heart, kidneys and other organs/connective tissues were imaged using a gamma camera. The animals were killed and the amounts of thrombi adherent to MHV components and organ-trapped emboli quantified using an ionization chamber and gamma counter. RESULTS: There was no statistically significant difference in the adhesion of 111In-labeled platelets to either control sewing rings (0.08 +/- 0.06% dose) or PEO-treated rings (0.19 +/- 0.21% dose). The thrombogenicity of MHV components in both animal groups was in the ascending order: Dacron ring > Teflon pledgets > polypropylene sutures > titanium housing > pyrolytic carbon. The number of platelet-emboli trapped in the organs was not significantly different between the two groups. CONCLUSIONS: Simple modifications may not reduce platelet thrombosis or wound-healing of the sewing ring in the acute phase, at which time several complex processes are activating and inactivating platelets and coagulant factors during CPB and implantation of MHVs.

Animals↗

PubMed1999

Methicillin resistance among staphylococci isolated from dogs.

OBJECTIVE: To determine whether methicillin-resistant staphylococci from dogs expressed the mecA gene and to determine what proportion of canine staphylococcal isolates positive for the mecA gene were resistant to oxacillin and other antibiotics. SAMPLE POPULATION: 25 methicillin-resistant (10 coagulase-positive and 15 coagulase-negative) and 15 methicillin-susceptible (8 coagulase-positive and 7 coagulase-negative) staphylococci isolated from dogs. PROCEDURE: All strains were tested for methicillin resistance by use of oxacillin agar screening and identified by use of standard techniques. Minimum inhibitory concentrations of 16 antibiotics were determined for all 40 isolates. A polymerase chain reaction method targeting a 533-basepair fragment of the mecA gene was used to detect mecA gene expression. RESULTS: 23 of the 25 methicillin-resistant isolates and none of the methicillin-susceptible isolates possessed the mecA gene. For 10 of 16 antibiotics, the proportion of mecA-positive isolates that were resistant or of intermediate susceptibility was significantly higher than the proportion of mecA-negative isolates that were resistant or of intermediate susceptibility. Only 1 methicillin-resistant coagulase-positive isolate was identified as Staphylococcus intermedius; the other 9 were identified as S. aureus. CONCLUSIONS AND CLINICAL RELEVANCE: Results confirm that staphylococci isolated from dogs may have methicillin resistance mediated by the mecA gene. Isolates positive for the mecA gene were more likely to be resistant to various antibiotics than were isolates negative for the mecA gene. Results suggest that in dogs, infections caused by staphylococci that have the mecA gene may be difficult to treat because of resistance to antibiotics.

Ampicillin Resistance↗