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Biomedical subjects

J L Watts

Publications and source records attributed to J L Watts.

87 records · Page 5Linked to original sources
PubMed1985

Evaluation of protein A and a commercial bacterin as vaccines against Staphylococcus aureus mastitis by experimental challenge.

Protein A and a commercial staphylococcal bacterin were evaluated by experimental challenge with Staphylococcus aureus (ATCC 29740). Thirty cows in first lactation were in three treatment groups, protein A, bacterin, and nonvaccinated controls. Studies were through three lactations and included bacteriological and cytological analyses of quarter milk samples. Rate of intramammary infection with Staphylococcus aureus was similar for vaccinated and unvaccinated cows. Rates of spontaneous cure within each lactation were significantly higher for vaccinated cows. For all three lactations, spontaneous cure rates were 83, 73, and 47% for protein A, bacterin, and control cows. Somatic cell counts were significantly lower for vaccinated cows for quarters infected with Staphylococcus aureus, but no differences were demonstrated for milk production by lactation. Incidence of clinical mastitis was higher in unvaccinated cows, but too few developed for a valid comparison.

Animals↗
PubMed1985

Field studies on linear dodecyl benzene sulfonic acid teat dip.

A teat dip containing 1.94% linear dodecyl benzene sulfonic acid and 12% glycerine, an anionic detergent formulation, was evaluated in two field trials on a commercial dairy. In Trial 1, the teat dip was compared to an undipped control in a split-herd design. Incidence of infection with Streptococcus agalactiae was reduced 57.8%; infections with presumptively identified Staphylococcus aureus were not reduced. Milking machine function and milking procedures may have affected teat dip effectiveness and incidence of udder infection. Streptococcus agalactiae was eradicated prior to Trial 2 in which the detergent teat dip was compared to a 1% iodophor product of proven efficacy. Incidence of Staphylococcus aureus infection was 40.5% lower in the detergent than in the iodophor group. Taxonomic studies on Staphylococcus species indicated that presumptive microbial identification resulted in erroneous conclusions concerning efficacy of the teat dip products. Importance of speciation of staphylococcal isolates is discussed.

Animals↗
PubMed1984

A case study of Streptococcus group G infection in a dairy herd.

In this paper an outbreak of bovine mastitis in a dairy herd caused by Streptococcus group G is described. Initial identification of the organism as Streptococcus agalactiae was based upon hemolysis, esculin reaction, and CAMP reaction observed on blood agar used for bulk milk analysis. Initial therapy with a penicillin-containing, lactating cow product cured 24.4% of all streptococcal infections. Definitive serogrouping by coagglutination determined that the majority of infections were due to a weakly-hemolytic, esculin-negative Streptococcus group G. Treatment with a cephalosporin, lactating cow product was only moderately successful (54.9%). Dry-cow therapy with 300 mg cephalosporin eliminated 69.5% of refractory infections. Animals remaining infected following dry-cow therapy were culled. Histopathological study of parenchymal tissue in the lower portion of infected quarters revealed mild damage and slight involutionary changes, whereas, deep parenchymal areas appeared relatively unaffected.

Animals↗
PubMed1984

A comparison of the zinc, copper and manganese status of very low birth weight pre-term and full-term infants during the first twelve months.

During a longitudinal study, hair samples and dietary intake data were collected from 50 pre-term (mean birth weight = 1054 +/- 234 g, mean gestational age = 29 +/- 2.5 weeks) and 60 full-term infants (mean birth weight = 3509 +/- 269 g, mean gestational age = 40 +/- 1 weeks) at 3, 6 and 12 months of age. Mean daily zinc, copper and manganese intakes were calculated using three-day dietary records and test-weight data for the breast-fed infants. Hair samples were analyzed for these elements by instrumental neutron activation analyses. The medium hair zinc concentration in the pre-term group at six months (81 micrograms/g) was lower (p less than 0.05) than that of the full-term group (144 micrograms/g) and was associated with lower mean dietary zinc intakes at 3 and 6 months. At 12 months, the median hair copper (12.5 micrograms/g) and manganese (0.18 micrograms/g) concentrations for the pre-term were lower (p less than 0.05) than those of the full-term infants (Cu = 16.5 micrograms/g; Mn = 0.25 micrograms/g) and were also associated with low dietary copper and manganese intakes.

Copper↗
PubMed1984

Evaluation of the Staph-Ident and STAPHase systems for identification of staphylococci from bovine intramammary infections.

The Staph-Ident and STAPHase systems (Analytab Products, Plainview, N.Y.) were compared with conventional methods for identification of staphylococci isolated from bovine intramammary infections. Adjunct testing by colony morphology, pigmentation, and biochemical tests was conducted to resolve discrepant identifications. The initial accuracies of the conventional scheme and Staph-Ident were 92.1 and 89.2%, respectively. Staphylococcus hyicus subsp. chromogenes could not be identified by means of the Staph-Ident test, but the addition of pigment production as a key character permitted identification of most strains. The final accuracy of the Staph-Ident was 94.3%. The STAPHase system was as accurate as the conventional tube coagulase method. The Staph-Ident and STAPHase systems are acceptable alternatives to conventional methods for identification of staphylococcal species isolated from bovine intramammary infections.

Animals↗
PubMed1984

Evaluation of teat dips with excised teats.

Thirty-eight teat dip formulations were evaluated for germicidal activity against Staphylococcus aureus and Streptococcus agalactiae with an excised teat model. Twenty-six of 27 iodophor products provided log reductions greater than 3 against Staphylococcus aureus, but only 13 against Streptococcus agalactiae. Log reductions obtained with two .2% quaternary ammonium and .5% cetylpyridium chloride products were greater than 4 against both organisms. A 1% benzyl alcohol formulation provided log reductions of 3.86 and 4.30 against Staphylococcus aureus and Streptococcus agalactiae. Germicidal activities of six novel formulations containing sodium chlorite were determined. Two products were effective against Staphylococcus aureus and Streptococcus agalactiae with log reductions greater than 4. One product provided a log reduction of 3; three products were ineffective.

Animals↗
PubMed1983

Evaluation of nine teat dip formulations under experimental challenge to staphylococcus aureus and streptococcus agalactiae.

Nine postmilking teat dips were evaluated by an experimental challenge model against either Staphylococcus aureus, Streptococcus agalactiae, or both. Formulations containing .9 and .6% sodium hypochlorite, 1% sodium dichloro-s-triazene-trione, .55% chlorhexidine gluconate, and .35% povidone iodine reduced incidence of Staphylococcus aureus infections 56.8, 28.3, 75.9, 92.5, and 77.9%. Incidence of infections with Streptococcus agalactiae was reduced 48.1 and 63.2% by 1.7 and 1% sodium dichloro-s-triazene-trione formulations. The 1% chlorhexidine gluconate and .35% povidone iodine products reduced Streptococcus agalactiae infections 71.0 and 67.0%. Three experimental 1% iodophor formulations reduced Streptococcus agalactiae infections 28.9, 44.8, and 50.7%. The experimental challenge model was refined further and provided an efficient method to determine efficacy of postmilking teat dips.

Administration, Topical↗
PubMed1983

Evaluation of spray application of postmilking teat sanitizer.

Application of postmilking teat sanitizer by spraying was evaluated in two experimental challenge trials with Streptococcus agalactiae (ATCC 27956) (McDonald 44). A .5% quaternary ammonium teat sanitizer was used in both studies. By direct comparison, teat spraying and dipping did not differ in effectiveness. Efficacy for the .5% quaternary ammonium compound was 58.6%, similar to results on the product applied as a dip (13).

Administration, Topical↗
PubMed1978

Apnea, hypoxemia, and aborted sudden infant death syndrome.

To find out whether there is any relationship between the ventilatory response to hypoxia and the sudden infant death syndrome (SIDS), we studied the effects of mild induced hypoxia (PIO2, 120 mm Hg = 17% oxygen) in 16 infants aged 2 weeks to 6 months. Eight had recurrent apneic spells (apnea group) (five had aborted SIDS and three had recurrent apnea in the intensive care nursery) and eight were "well" preterm infants about to fly in a pressurized airplane (PIO2, 120 mm Hg) (control group). Mean birth weights were 2,245 and 1,400 gm and mean gestational ages were 35 and 30 weeks. Postconceptual ages (41.8 and 41.3 weeks) were almost identical. Heart rate was obtained from an ECG, and respiratory rate and pattern were obtained from a pneumogram. In addition, end-tidal PCO2 and PN2 or PO2 were obtained with a nasal catheter and gas analyzers. In the apnea group with inhalation of 17% oxygen, we observed an increase in periodic breathing and an increase in both rate and total duration of respiratory pauses. In the control group there were no significant changes. Heart rate and PCO2 did not change in either group. Our findings suggest that infants prone to apnea may have unique respiratory responses to mild induced hypoxia.

Apnea↗
PubMed1977

Chronic pulmonary disease in neonates after artificial ventilation: distribution of ventilation and pulmonary interstitial emphysema.

To determine pulmonary function abnormalities in patients with neonatal bronchopulmonary dysplasia (BPD), we measured distribution of ventilation by nitrogen washout, minute and tidal volume, and arterial and alveolar gases in three groups of ten preterm infants with similar birth weights (mean = 1,340 g) and gestational ages (mean = 30.3 weeks). Infants in group A were never artificially ventilated, those in group B were ventilated but had no subsequent BPD, and those in group C were ventilated and developed BPD. Infants with BPD had severe maldistribution of ventilation (pulmonary clearance delay 223% versus 47% and 60% for groups A and B). They had decreased tidal volumes (5.3 ml versus 7.0 and 6.2 ml) and higher respiratory rates (60/min versus 47 and 48) but similar minute volumes. They also had increased PaCO2 (53.6 torr versus 41.9 and 43.4 torr) and increased arterial-alveolar carbon dioxide gradients (6.8 torr versus 3.1 and 1.8 torr). There was no statistically significant difference between groups B and C for the time spent in fractional inspired oxygen greater than 0.40 and greater than 0.60, or the time ventilated for intubated, or the incidence of patent ductus arteriosus. Early pulmonary interstitial emphysema was much more common in the infants who subsequently developed BPD (eight of ten versus two of ten, P less than .01).

Chronic Disease↗
PubMedDate not supplied

Minimum inhibitory concentration determinations for various antimicrobial agents against 1570 bacterial isolates from turkey poults.

Minimum inhibitory concentrations (MICs) were determined for 1570 bacteria from eight geographic locations (1204 Escherichia coli, 231 other enteric gram-negative bacilli [including Citrobacter spp., Enterobacter spp., Klebsiella spp., Proteus spp., and Salmonella spp.], 31 Pseudomonas spp., 18 coagulase-positive staphylococci, 26 coagulase-negative staphylococci, and 55 streptococci and enterococci) by the National Committee for Clinical Laboratory Standards broth microdilution procedure. Antimicrobial agents tested included ampicillin, ceftiofur, enrofloxacin, erythromycin, florfenicol, gentamicin, neomycin, spectinomycin, sulfamethazine, tetracycline, and trimethoprim/sulfadiazine. Against the E. coli strains tested, ceftiofur, enrofloxacin, gentamicin, and trimethoprim/sulfadiazine were the most active compounds with MIC at which 50% of the strains are at or below (MIC50) = 0.5, < or = 0.03, 0.5, and 0.13 microg/ml, respectively, and MIC at which 90% of the strains are at or below (MIC90) = 1.0, 0.13, 32.0, and 2.0 microg/ml, respectively. Ampicillin, florfenicol, neomycin, and spectinomycin were the next most active compounds against the E. coli strains, with MIC50 = 4.0, 4.0, 16.0, and 16.0 microg/ml, respectively. MIC90 values for these compounds against E. coli strains were > 32.0, 8.0, 512.0, and > 128.0 microg/ml, respectively. The remaining compounds exhibited limited, strain-dependent activity against the E. coli strains tested. As with the E. coli, enrofloxacin, ceftiofur, and trimethoprim/sulfadiazine were also the most active compounds against the 231 other enteric organisms tested, with MIC50 < or = 1.0 microg/ml for all of these genera. The remaining compounds exhibited limited activity against these genera. Against the gram-positive cocci tested, ampicillin, enrofloxacin, ceftiofur, and trimethoprim/sulfadiazine were most active, whereas the remaining compounds exhibited strain-dependent activity. When MIC data for E. coli were summarized separately, differences were observed between the geographic locations for the various antimicrobial agents. In conclusion, ceftiofur, enrofloxacin, and trimethoprim/sulfadiazine were the most active of the compounds tested against all of the bacterial strains.

Animals↗