Use of eosin methylene blue agar to differentiate Escherichia coli from other gram-negative mastitis pathogens.
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Biomedical subjects
Publications and source records attributed to J R Roberson.
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Twin 17-day-old crossbred male lambs were examined to determine the cause of weakness and failure to thrive. Hypercalcemia attributable to hypervitaminosis D was diagnosed. The milk replacer or an accidental overdose of an injectable vitamin D product was suspected to be the source, although a definite cause was not confirmed. Lambs responded favorably to palliative treatment (administration of saline [0.9% NaCl] solution to induce calcium diuresis) and changing the diet to another milk replacer.
We report on two patients with rare 6q duplications. The karyotype of patient 1 is 46,XY,dup(6)(q21q23.3). The karyotype of patient 2 is 46,XX,dup(6)(q21.15q23.3). These two patients have some nonspecific physical findings in common including a depressed nasal bridge, epicanthal folds, mild heart defects, and developmental delay, but each had other congenital anomalies.
The study objective was to identify probable sources and modes of transmission of 91 Staphylococcus aureus isolates obtained from the colostrum of 76 heifers at parturition. Sources cultured were milk (including colostrum), heifer body sites (teats, muzzle, rectum, vagina, and lacteal secretions), and environmental sites (bedding, insects, housing, water, feedstuffs, humans, nonbovine animals, air, and equipment). Staphylococcus aureus isolates were characterized by 63 phenotypic traits. A similarity coefficient was calculated by herd to identify the S. aureus that most closely resembled the S. aureus obtained from heifer colostrum. Staphylococcus aureus from a heifer's colostrum was compared with all preexisting S. aureus isolates from that heifer's herd. Isolates that were > or = 90% similar were considered to be identical. Because 30 (of the 91) S. aureus isolates from heifer colostrum were collected prior to environmental sampling, only 61 S. aureus isolates from heifer colostrum were available for comparison among all three sources. Possible sources of S. aureus from heifer colostrum at parturition were milk (70%, 43 of 61 isolates), heifer body sites (39%, 24 of 61), environmental sites (28%, 17 of 61), or no identified source (16%, 10 of 61). Three heifers with intramammary infection (IMI) from S. aureus at parturition had the same S. aureus on their teats prior to parturition. Milk was the only source identified for 41% (25 of 61) of isolates from heifer colostrum. Isolates from heifer body sites were the only source identified for 5% (3 of 61) of heifer colostrum isolates. Staphylococcus aureus from the environment was never the sole possible source for S. aureus from heifer colostrum. Data suggest that the major sources of S. aureus IMI in heifers at parturition are milk and heifer body sites. Contact among heifers may be an important mode of transmission of S. aureus leading to IMI in heifers at parturition.
This study was designed to define the relationship between different combinations of prosthetic head diameters, neck lengths, and acetabular containment angles, and range of motion before component impingement. Three cadaveric pelves with attached lower limbs were mounted in their correct anatomic position. Acetabular and modular femoral stems were inserted into each of the six hips. For each combination of femoral head diameter, neck length, and acetabular liner overhang, the range of motion to impingement was measured in flexion, extension, abduction, adduction, external rotation, internal rotation, and internal rotation with 90 degrees hip flexion. These experiments suggest that the maximum range of motion before impingement can be attained by increasing the prosthetic head diameter and avoiding longer neck lengths with skirts. Acetabular liners with greater overhang decrease motion in all planes except flexion when the overhang is positioned posteriorly.
OBJECTIVE: To determine prevalence and relevance of coagulase-positive Staphylococcus hyicus and S intermedius intramammary infections (IMI) in dairy cows and determine the ability of the 4-hour tube coagulase (TC) test to differentiate the coagulase-positive staphylococci (CPS). DESIGN: Prevalence of CPS was determined for primiparous cows (point prevalence and prevalence at first parturition) and multiparous cows (point prevalence) of 2 herd groups: < 6% CPS IMI prevalence = low prevalence (LP); > 10% CPS IMI prevalence = high prevalence (HP). SAMPLE POPULATION: For prevalence, cows of 22 dairy herds. For TC, 1,038 CPS strains isolated from cow milk. PROCEDURE: Speciation of CPS from aseptically collected composite milk samples was performed. Coagulase-positive isolates from 4 cow groups were tested for their ability to coagulate rabbit plasma by 4 hours: LP and HP primiparous cows at parturition, and LP and HP cows any time after first parturition. RESULTS: Of 487 CPS in the prevalence study, 82.1% were S aureus, 17.7% were coagulase-positive S hyicus, and 0.2% were S intermedius. Of all CPS IMI in LP herds, 34% were coagulase-positive S hyicus; of all CPS IMI in HP herds, 9% were coagulase-positive S hyicus. Coagulase-positive S hyicus appeared to persist to the end of lactation in 4 cows (mean linear somatic cell count = 3.7). The TC test was > or = 97% sensitive, < or = 33% specific, and had a predictive value positive range of 60 to 97% for S aureus isolates. CONCLUSION: Coagulase-positive S hyicus appears capable of inducing chronic, low-grade IMI. Staphylococcus intermedius does not appear to be an important mastitis pathogen. The TC test is not valid to use as the sole method to differentiate CPS species.
PURPOSE: To determine whether findings on plain radiographs alter clinical care in outpatient management after hip arthroplasty. MATERIALS AND METHODS: From June 1, 1993, through February 28, 1994, one arthroplasty surgeon saw 148 outpatients (age range, 15-86 years) after hip arthroplasty (163 prostheses). The surgeon made decisions about clinical management before he reviewed the plain hip radiographs. After he reviewed the radiographs, he recorded any changes in the management plan. RESULTS: In only one case did the radiographic findings change patient treatment. The prosthesis in this relatively asymptomatic patient had been in place for over 9 years and appeared clinically to be functioning well, but radiographs demonstrated aggressive granulomatosis. Therefore, the patient underwent revision arthroplasty. In the remaining 147 patients, radiographic findings had no impact on clinical management. CONCLUSION: Radiographic evaluation may be most beneficial in patients with hip prostheses that have been in place for many years to rule out asymptomatic bone loss due to aggressive granulomatosis.
The technique of hip arthroplasty is at least 30 years old and currently is performed 120,000 times per year in the United States [1]. Changes in materials and surgical techniques have markedly decreased the prevalence of infection and aseptic loosening. At the same time, other complications such as stress shielding and aggressive granulomatosis have become increasingly important complications of joint replacement [2]. All four of these entities manifest radiographically as periprosthetic lucency (Fig. 1.). The purpose of this essay is to illustrate the plain film findings of each of these complications.
OBJECTIVE: The purpose of this study was to evaluate the spectrum of plain radiographic findings in patients with septic hip prostheses. MATERIALS AND METHODS: Radiographs of 20 confirmed infected hip prostheses were examined for the presence or absence of lucency, type of lucency (focal or nonfocal), rapidity of radiographic change, periostitis, subsidence, and cement fracture. RESULTS: Findings were normal in 10 prostheses, but nonfocal lucencies mimicking mechanical loosening were seen in four cases. Two cases showed focal bone loss, indistinguishable from aggressive granulomatosis. A variety of findings, including subsidence and periostitis, were seen in the remaining four prostheses. CONCLUSION: Plain radiographs of septic hip prostheses often show normal findings but can show focal bone loss that mimics aggressive granulomatosis.
Objectives were to determine the prevalence of coagulase-positive staphylococcal IMI in primiparous cows at first parturition, to contrast the differences in coagulase-positive staphylococcal IMI in primiparous cows at parturition in herds with high and low prevalences of coagulase-positive staphylococcal IMI in the lactating herd, and to determine the percentage of primiparous cows having persistent coagulase-positive staphylococcal IMI. Milk samples were collected aseptically from cows at the start and end of the study, at dry-off, and at parturition. Herds (n = 18) were split evenly into two categories: high (> 10%) or low (< 5%) prevalence of coagulase-positive staphylococcal IMI. At the start, the mean prevalence of coagulase-positive staphylococcal IMI in high prevalence herds was 30%, ranging from 13 to 65%, and in low prevalence herds was 2%, ranging from 0 to 5%. Overall the prevalence of coagulase-positive staphylococcal IMI in primiparous cows at parturition was 8.1% (67 of 828), ranging from 0 to 27%. Although primiparous cows from high prevalence herds had a higher prevalence of coagulase-positive staphylococcal IMI (9.2%; 40 of 436) at parturition than did primiparous cows from low herds (6.9%; 27 of 392), the difference was not significant. Of primiparous cows with coagulase-positive staphylococcal IMI at parturition, 43% had coagulase-positive staphylococcal IMI at least 2 mo after parturition. Primiparous cows with coagulase-positive staphylococcal IMI at parturition may represent significant reservoirs of infection to uninfected herdmates.
The purposes of this study were to identify sources of Staphylococcus aureus on dairies and to determine whether S. aureus colonization of heifer body sites increases the risk of S. aureus IMI at parturition. In herds with high (> 10%) or low (< 3%) prevalence of S. aureus IMI, S. aureus was isolated from heifer teat skin, heifer external orifices, housing, feedstuffs, humans, nonbovine animals, air, and equipment. Additionally, in herds with high prevalence, S. aureus was isolated from bedding, insects, and water. The predominant sources of S. aureus for both groups were other IMI and heifer body sites. Heifers with prepartum lacteal secretions with S. aureus were at greater risk of S. aureus IMI at parturition than were prepartum heifers with lacteal secretions that were negative for S. aureus. Heifers with teat skin colonized by S. aureus were 3.34 times more likely to have S. aureus IMI at parturition than were noncolonized heifers. Overall, 35% of 700 heifers were colonized with S. aureus on a body site at least once. Although colonizations of most body sites appeared to be transient, a few heifers were colonized on the same site for 1 yr. Persistently colonized heifers may represent the primary reservoirs of S. aureus for other heifers.
Aggressive granulomatosis is a potentially devastating complication of joint-replacement surgery. This condition likely represents a foreign body reaction to particulate metal, methylmethacrylate or polyethylene. The authors describe a 51-year-old woman in whom aggressive granulomatosis developed after total knee arthroplasty. Plain radiographs over a 3-year period showed progressively expanding focal areas of bone loss. Revision arthroplasty was necessary to prevent pathologic fracture.
The type C staphylococcal enterotoxins (SEC) are a group of highly conserved proteins with significant immunological cross-reactivity. Although three antigenically distinct SEC subtypes (SEC1, SEC2, and SEC3) have been reported in the literature, we observed that the isoelectric points of SEC from several Staphylococcus aureus isolates are different from those of any of these three subtypes. This observation led us to propose that additional SEC molecular variants exist. For assessment of this possibility, the sec genes from representative human, animal, and food isolates were cloned and sequenced. The toxins encoded by the 18 isolates used in this study included five unique SEC proteins in addition to SEC1, SEC2, and SEC3. Six of the SEC proteins (including SEC1, SEC2, and SEC3) were produced by human and food isolates. Analysis of seven bovine and ovine isolates showed that isolates from each animal species produced a unique host-specific SEC. All of the SEC caused lymphocyte proliferation, although some of the toxins differed in their ability to stimulate cells from several animal species. An explanation for these results, which is supported by our phenotypic analysis of Sec+ staphylococcal isolates, is that toxin heterogeneity is due to selection for modified SEC sequences that facilitate the survival of S. aureus isolates in their respective hosts.
PURPOSE: The accuracy of fluoroscopy-guided hip aspiration in the diagnosis of infection in hip prostheses was evaluated. MATERIALS AND METHODS: Results from 147 preoperative aspiration cultures were compared with results of operative cultures. The relative costs of aspiration and nuclear medicine studies were also compared. RESULTS: With the operative culture results as the standard, sensitivity of hip aspiration was 92.8% and specificity was 91.7%. The negative and positive predictive values were 99.2% and 54.2%, respectively. Aspiration arthrography costs approximately 20% as much as complementary technetium sulfur colloid-indium-111 granulocyte scans, the most accurate nuclear medicine study used to evaluate potentially infected hip prostheses. CONCLUSION: Hip aspiration is an accurate and cost-effective method of evaluating the potentially infected hip prosthesis.
Since some patients with Ullrich-Turner syndrome (UTS) have mental retardation, we reviewed our experience to look for a high-risk subgroup. Among 190 UTS and gonadal dysgenesis patients with X chromosome abnormalities, 12 had mental retardation. All of the six (100%) with a small ring X were educable (EMI) or trainable mentally impaired (TMI) with more severe delay than expected in UTS. Among the 184 with other X abnormalities, only 6 had similar delays (2 from postnatal catastrophes), for a frequency of 3.3% mental retardation among those without a small ring X; only 2.2% of these had unexplained mental retardation. Polymerase chain reaction studies showed no Y-derived material in the 2 patients who were evaluated, and in situ hybridization confirmed X origin of the ring in the 6 subjects who were evaluated. We describe the phenotype of the 6 individuals with a small ring X, and an additional 2 patients with a small ring X who were identified outside the survey. The subjects with a small ring X comprised a clinically distinct subgroup which had EMI/TMI and shorter stature than expected in UTS. Seizures and a head circumference less than 10th centile were observed in half of the patients with a small ring X, and strabismus, epicanthus, and single palmar creases were present in more than half. A "triangular" face in childhood, pigmentary dysplasia, sacral dimple, and heart defects were also common. Neck webbing appeared to be less frequent than in 45,X. We hypothesize that the high risk of mental retardation in this form of the UTS results from lack of lyonization of the ring X due to loss of the X inactivation center. Excluding those with a small ring X, mental retardation is not significantly increased in patients with UTS.
The purpose of this study was to determine the minimum number of tests that could be used to differentiate between the coagulase-positive strains of staphylococcus: Staphylococcus aureus, Staphylococcus hyicus, and Staphylococcus intermedius. Eighty coagulase-positive strains of each of the three species were examined. The five tests conducted were growth on modified Baird-Parker agar, growth on P agar supplemented with acriflavin, production of acetoin, anaerobic fermentation of mannitol, and presence of beta-galactosidase. Positive test percentages for S. aureus were 100% for growth on modified Baird-Parker agar, 100% for growth on P agar supplemented with acriflavin, 94% for production of acetoin, 99% for anaerobic fermentation of mannitol, and 0% for presence of beta-galactosidase. Positive test percentages for S. intermedius were 0% for growth on modified Baird-Parker agar, 0% for growth on P agar supplemented with acriflavin, 1% for production of acetoin, 0% for anaerobic fermentation of mannitol, and 100% for presence of beta-galactosidase. S. hyicus isolates were negative in all five tests. Results from the 240 coagulase-positive staphylococcus strains tested would suggest correct identification of coagulase-positive staphylococci with P agar supplemented with acriflavin and the beta-galactosidase test. These two tests are simple to conduct and result in quick and easy differentiation of the three coagulase-positive staphylococcal species.
The cause of bone loss from the proximal femur after total hip arthroplasty is multifactorial and may progress to a degree at which loss of support for the femoral component occurs. The most durable means of reconstructing the deficient proximal femur involves bone grafting techniques designed to restore mechanical integrity. Because there is seldom an adequate quantity of autogenous bone available, allograft bone is frequently used. The indications and limitations of this procedure are described as are other treatment options.
Deep venous thrombosis (DVT) is the most common complication of total hip arthroplasty. This article discusses the pathogenesis and diagnosis of DVT and recommends prophylaxis and treatment options.