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J L Watts

Publications and source records attributed to J L Watts.

At least 73 records · Page 4Linked to original sources
PubMed1989

Evaluation of the Rapid Strep system for identification of gram-positive, catalase-negative cocci isolated from bovine intramammary infections.

The Rapid Strep system (Analytab Products, Plainview, NY) was used to identify 199 gram-positive, catalase-negative cocci isolated from bovine intramammary infections. The system accurately identified 88.4% of isolates. The system identified 100% of 46 Streptococcus agalactiae, 100% of 48 Streptococcus dysgalactiae, 54.5% of 11 Streptococcus equinus, and 96.2% of 53 Streptococcus uberis isolates. Enterococcus spp. were identified correctly 83.3% of the time. One of 4 Streptococcus saccharolyticus strains was identified as Streptococcus bovis, the previous classification for this organism, and 8 Streptococcus equi ssp. equi strains were misidentified as Streptococcus dysgalactiae. The Rapid Strep system was determined to be an acceptable alternative to conventional methods for identification of gram-positive, catalase-negative cocci isolated from bovine intramammary infections.

Animals↗
PubMed1989

Effects of recombinant granulocyte colony-stimulating factor on Staphylococcus aureus mastitis in lactating dairy cows.

The in vivo effects of recombinant human granulocyte colony-stimulating factor on blood and milk leukocytes in dairy cows was examined. A 2-fold increase in peripheral white blood cell counts was observed by d 5 of treatment and peaked on d 12 with values 3-fold those of controls. Counts remained elevated above pretreatment values during the treatment period, then returned to normal by d 23 of the trial. Differential white blood cell counts demonstrated that neutrophils predominated (73.8%) in treated cows versus controls (22.1%) during the treatment period. Immediately prior to experimental challenge with Staphylococcus aureus, milk SCC were 582 x 10(3) and 261 x 10(3)/ml, and percentages milk neutrophils were 64.4 and 45.3, respectively, in treated and control cows. After challenge, a 46.7% reduction in new infections was observed in quarters of treated cows compared with controls. Recombinant human granulocyte colony-stimulating factor was a granulopoietic growth and differentiation factor in the cow, and the resulting leukocytosis into the mammary gland may have been protective against experimental bacterial challenge.

Animals↗
PubMed1989

Prevalence of staphylococcal species in four dairy herds.

The prevalence of staphylococcal species isolated from bovine mammary glands was determined in four dairy herds. Staphylococcus aureus and S hyicus were the predominant organisms isolated from cows in a herd with a bulk milk somatic cell count (SCC) greater than 900 X 10(3). One herd with a bulk milk SCC of 565 X 10(3) had a high incidence of S aureus while the predominant coagulase-negative species were S epidermidis and S hyicus. S hyicus predominated in two herds with bulk milk SCC less than 200 X 10(3); prevalence of S aureus was low. The impact of herd management practices such as post-milking teat antisepsis on distribution of staphylococcal species is discussed.

Animals↗
PubMed1988

Etiological agents of bovine mastitis.

A total of 137 microbial species, subspecies and serovars have been isolated from the bovine mammary gland. Nucleic acid hybridization studies have restructured the classification of many mastitis pathogens. Availability of defined species descriptions has permitted greater insight into the distribution and pathogenicity of many previously unrecognized microorganisms associated with bovine mastitis. Precise epidemiological studies are needed to better delineate the role of some microorganisms in bovine mastitis and to aid development of improved control methods.

Animals↗
PubMed1988

Evaluation of the Rapid Mastitis Test for identification of Staphylococcus aureus and Streptococcus agalactiae isolated from bovine mammary glands.

A latex agglutination test system (Rapid Mastitis Test [RMT]; Immucell, Portland, Maine) containing reagents for the identification of Staphylococcus aureus and Streptococcus agalactiae from bovine intramammary infections was evaluated with 527 staphylococcal and 267 streptococcal isolates. The RMT Staphylococcus aureus reagent detected 94.2% of 242 Staphylococcus aureus isolates, 80% of 25 Staphylococcus intermedius isolates, and 42.8% of 21 tube coagulase-positive Staphylococcus hyicus isolates. All Streptococcus agalactiae isolates were correctly identified by the RMT Streptococcus agalactiae reagent. Cross-reactions were observed with one Streptococcus dysgalactiae and three Streptococcus uberis strains. The RMT was found to be an acceptable method for the detection of Staphylococcus aureus and Streptococcus agalactiae isolated from bovine mammary glands. The occurrence of coagulase-positive staphylococci other than Staphylococcus aureus requires biochemical testing for species level identification.

Animals↗
PubMed1988

Determination of teat dip germicidal activity using the excised teat model.

Fifteen postmilking teat antiseptics were evaluated in seven trials using the excised teat model. All products were tested against Staphylococcus aureus Newbould 305 and Streptococcus agalactiae Cornell 48. Eight of nine iodophor products provided log reductions greater than 3 against Staph. aureus and Strep. agalactiae. A .045% iodophor product was ineffective. A .5% chlorhexidine product yielded a log reduction of 3.22 against Staph. aureus but only 2.92 against Strep. agalactiae. Two products containing fermented milk emulsified in detergent were tested upon receipt and after 1 yr storage. Fresh product provided log reductions greater than 3 against both pathogens. Storage for 1 yr resulted in minimal loss of germicidal activity. Three products containing 1, .5, and .2% dodecylaminoalkyl glycine provided log reductions greater than 3.5 against Staph. aureus and greater than 4 log reduction against Strep. agalactiae.

Animals↗
PubMed1988

Characterization and identification of streptococci isolated from bovine mammary glands.

A total of 317 gram-positive, catalase-negative cocci isolated from bovine mammary glands were characterized and identified using current species descriptions. Two hundred eighty-seven isolates (90.5%) could be placed in 11 distinct species. Streptococcus uberis was the most frequently encountered species and could be separated into two previously described genetic types based upon sucrose utilization. Streptococcus dysgalactiae and a newly described species, Streptococcus saccharolyticus, were the most frequently isolated organisms from teat canal swabs. Thirty isolates could not be placed in currently described species. A proposed identification scheme based upon serological grouping and seven biochemical tests would permit 24 h identification of streptococci isolated from bovine mammary glands.

Animals↗
PubMed1988

Antimicrobial susceptibility and beta-lactamase testing of staphylococci isolated from dairy herds.

Evaluation of 722 staphylococcal isolates from seven dairy herds revealed marked herd differences in antimicrobial susceptibility patterns. A low overall resistance to penicillin was noted for Staphylococcus aureus, although isolates from three herds had greater than or equal to 16% penicillin resistance. Other staphylococcal species demonstrated a higher resistance to penicillin than did S. aureus. The predominant staphylococci other than S. aureus were S. hyicus and S. chromogenes for six of the seven herds while S. simulans and S. epidermidis predominated in one herd. beta-Lactamase testing using a commercially available chromogenic cephalosporin was an accurate predictor of penicillin resistance for S. aureus. Staphylococcus hyicus, S. chromogenes, and S. epidermidis that were penicillin resistant by susceptibility testing demonstrated negative beta-lactamase results of 35, 11, and 9%, respectively. Retesting of these isolates after exposure to penicillin resulted in positive beta-lactamase results, indicating induction of beta-lactamase. These results indicate the variability in antimicrobial susceptibility patterns for staphylococci and suggest the importance of epidemiologic knowledge of a dairy herd to guide initial therapy.

Animals↗
PubMed1988

Antibiotic treatment of mastitis: comparison of intramammary and intramammary plus intramuscular therapies.

Efficacy of two therapy regimens for subclinical Staphylococcus aureus bovine mastitis was evaluated. Forty-nine lactating cows with a total of 78 subclinically infected quarters were included. Cows were divided into two treatment groups. Group 1 received intramammary infusion at each milking for six milkings with a commercial lactating cow product containing 62.5 mg of amoxicillin. Group 2 received the same intramammary infusion regimen plus one intramuscular injection daily of 9,000,000 U procaine penicillin G for 3 d. The combination of intramammary and intramuscular treatment resulted in bacteriologic cure of 51.4% of quarters and 48% of cows compared to 25% of quarters and 30.4% of cows for intramammary infusion alone. Quarters where infections were not cured supported more growth of S. aureus during treatment than glands that were cured. Mean antibiotic concentration in fore-milk samples during treatment were lower in quarters that were cured. Somatic cell counts of milk from quarters that were not cured were higher prior to initiation of treatment than those cured. Data suggest that further evaluation of new regimens for treatment of subclinical S. aureus mastitis is warranted.

Amoxicillin↗
PubMed1987

Synergistic hemolysis associated with coagulase-negative staphylococci isolated from bovine mammary glands.

A total of 353 coagulase-negative staphylococcus (CNS) isolates from infected bovine mammary glands were tested for cytolysin production by using the synergistic hemolysin assay (SHA). Overall, 34.6% of CNS isolates were SHA positive. Human-associated, coagulase-negative staphylococcal species contained the greatest number of SHA-positive strains. Milk leukocyte levels expressed as somatic cell counts (SCC) were elevated with SHA-positive Staphylococcus epidermidis, Staphylococcus hominis, and Staphylococcus warneri strains. Elevated SCC levels were associated with strains of Staphylococcus hyicus and Staphylococcus chromogenes. However, no difference in SCC levels was observed between SHA-positive and SHA-negative strains. Results indicated that the SHA was a sensitive test for the detection of cytolysin-producing CNS.

Animals↗
PubMed1987

Effects of milk on activity of antimicrobics against Staphylococcus aureus isolated from bovine udders.

Addition of milk to Mueller-Hinton susceptibility test medium permitted measurement of milk effect on agar disc diffusion zone diameters obtained from Staphylococcus aureus herd isolates and stock strains. Milk reduced zone diameters for all antimicrobics tested when compared with zones obtained by standard methods. Antimicrobics most affected included novobiocin, streptomycin, gentamycin, tetracycline, and vancomycin. Growth curves of a reference strain of Staphylococcus aureus in Mueller-Hinton broth with and without milk indicated no effect on growth rate of the organism, suggesting the observed effect was due to the action of milk on the antimicrobics being tested. The described method offers a simple in vitro test for milk effects on antimicrobic activity.

Animals↗
PubMed1986

Evaluation of a rapid inoculum standardization system for antimicrobial susceptibility testing of bacterial isolates from the bovine mammary gland.

A commercially available rapid inoculum standardization system (RISS) was compared to the broth inoculum standardization method (BIS) for antimicrobial susceptibility testing of bacterial isolates from the bovine mammary gland. Overall agreement between RISS and the BIS method was 95.9%. RISS bypasses the 2-8 h incubation period required by BIS, thus providing antimicrobial susceptibility test data in a more timely manner. RISS was determined to be an acceptable alternative method to the BIS method for preparation of standardized inoculum for antimicrobial susceptibility testing of bovine mammary gland isolates.

Animals↗
PubMed1986

A comparison of the STAPH-Ident and STAPH-Trac systems to conventional methods in the identification of staphylococci isolated from bovine udders.

The STAPH-Ident and STAPH-Trac systems (Analytab Products, Plainview, N.Y.) were compared to conventional methods for identification of staphylococci isolated from bovine udders. The STAPH-Ident system identified 80.5% of isolates correctly. An additional 7.6% of Staphylococcus hyicus strains were delineated from S. epidermidis by characterizing acetoin and pigment production. Final accuracy of the STAPH-Ident system was 88.1%. The STAPH-Trac system identified 66.1% of isolates. Negative phosphatase tests for 42.3% of S. hyicus strains resulted in misidentification as S. simulans. Consequently, only 45.5% of S. hyicus isolates were identified correctly by the STAPH-Trac system. Minor modification of each system would permit accurate, rapid identification of staphylococci isolated from bovine udders.

Animals↗
PubMed1986

Evaluation of the Minitek gram-positive set for identification of staphylococci isolated from the bovine mammary gland.

The Minitek Gram-Positive Set was evaluated as a means of identifying staphylococci isolated from bovine mammary glands. Initial accuracy was 79.2%. Misidentification of isolates due to data base deficiencies resulted with the animal-associated species Staphylococcus intermedius and S. hyicus. Minor modification to account for data base deficiencies permitted recognition of 87.7% of the isolates. Incorporation of additional veterinary isolates into the data base would improve the accuracy of the Minitek system and enhance acceptance by veterinary microbiologists.

Animals↗
PubMed1986

Identification of staphylococci from bovine udders: evaluation of the API 20GP system.

The API 20GP system (Analytab Products, Plainview, NY) correctly identified 56.1% of staphylococci isolated from the bovine mammary gland. The system identified 90.2% of Staphylococcus aureus strains, but failed to recognize strains of Staphylcoccus hyicus and others. Poor performance was attributed to the limited number of veterinary strains contained in the profile index data base. The API 20GP was determined to be an unacceptable method for identification of staphylococci isolated from the bovine mammary gland.

Animals↗
PubMed1986

Prevalence and effects of intramammary infection in beef cows.

Prevalence and effects of intramammary infection in 322 beef cows was determined during three calving intervals. Intramammary infection was confirmed in 37% of cows and 18.1% of quarters. Coagulase-positive staphylococci accounted for 17.9% of infections with Staphylococcus aureus isolated from 7.1% of cows. Coagulase-negative staphylococci and micrococci accounted for the remainder of infectious organisms. Butterfat and total protein levels were reduced 27.3 (P less than .05) and 25.5% (P less than .01), respectively, in milk from quarters infected with S. aureus. Somatic cell counts were elevated (P less than .001) with 3,827 X 10(3) cells/ml for S. aureus-infected quarters as compared with 555 X 10(3) cells/ml for uninfected quarters. Somatic cell counts were negatively correlated with 210-d calf weaning weights. Staphylococcus aureus-infected cows weaned calves weighing 19.1 kg less (P less than .01) than uninfected cows. At a present market value of $1.65/kg, economic losses were placed at $31.43/calf from cows infected with S. aureus in one or more quarters.

Animals↗
PubMed1986

Evaluation of .5% and 1% iodophor teat dips on commercial dairies.

Two postmilking teat dips containing .5 and 1% iodine were evaluated for approximately 8 mo under conditions of natural exposure to mastitis pathogens on four commercial dairy farms. In the two herds using .5% iodophor, incidence of intramammary infection with Staphylococcus aureus and Streptococcus agalactiae was reduced 68.3 and 46.2%, respectively. When numbers of new infections with both pathogens were combined, efficacy for the .5% iodophor was 62.3%. In the two herds using 1% iodophor, incidence of intramammary infection with Staph. aureus and Strep. agalactiae was reduced 52.4 and 70.7%, respectively. When numbers of new infections with both pathogens were combined, efficacy for the 1% iodophor was 64.3%. Efficacy of teat dips was variable against coagulase-negative staphylococci and Corynebacterium bovis.

Animals↗