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Biomedical subjects

R S Steele

Publications and source records attributed to R S Steele.

8 recordsLinked to original sources
PubMed2000

Characterization of erythromycin-resistant methylase genes from multiple antibiotic resistant Staphylococcus spp isolated from milk samples of lactating cows.

OBJECTIVE: To isolate and characterize erythromycin-resistant methylase genes in multiple-antibiotic resistant staphylococci isolated from milk samples. ANIMALS: 300 lactating cows. PROCEDURE: 23 erythromycin-resistant staphylococci were isolated from milk samples of 300 lactating cows. The prevalence of erythromycin-resistant methylase (erm) genes, ermC and ermA genes, and the multicomponent macrolide efflux pump in staphylococci msrA genes were identified and characterized by use of multiplex polymerase chain reaction (PCR), Southern hybridization, restricted fragment length polymorphism (RFLP) analysis, and dot-blot hybridization. RESULTS: Biochemical characterization indicated that 3 of 23 (13%) isolates were coagulase-positive Staphylococcus aureus, and the rest were coagulase-negative. Multiplex PCR resulted in amplification of a 520-base pair (bp) region of the ermC gene from the cell lysates of a strain of S simulans M-21 and S sciuri M-28. The ermC gene in both isolates was found on a 3-kilobase plasmid. The ermA gene was found on the chromosome of 21 isolates, and 6 RFLP patterns were observed. None of the isolates harbored the msrA gene. CONCLUSIONS: Erythromycin-resistant Staphylococcus spp isolated from milk samples of lactating cows may serve as reservoirs of erm genes homologous to those described in human isolates. However, the chromosomal insert patterns and prevalence of these genes, the sizes of plasmids harboring the genes, and the number of inserts of the genes (copy number) may differ from that of human isolates.

Animals↗
PubMed1998

Molecular identification of a Stenotrophomonas species used in the bioassay for erythromycin in aquaculture samples.

A bacterial strain isolated from aquaculture pond slurry, which was extremely sensitive to erythromycin, was used to detect erythromycin at levels as low as 0.05 micrograms ml-1 in aquaculture water, sediments and soil samples. Identification of the indicator organism was attempted by 16S rRNA sequencing, biochemical profile, fatty-acid analysis and polymerase chain reaction (PCR). GenBank comparison showed that the 16S rRNA sequence of the strain was similar to those of more than 20 copies of Xanthomonas and Stenotrophomonas. The position of the strain in a phylogenetic tree based on the 16S rRNA gene sequence comparison is in a cluster of Stenotrophomonas. The fatty-acid analysis also showed that the strain is similar to Stenotrophomonas maltophilia. However, the biochemical profile of the strain is most similar to Xanthomonas campestris, except that it can utilize maltose, which is similar to S. maltophilia. Polymerase chain reaction results showed that the strain is different from X. campestris, S. maltophilia and other Xanthomonas species tested. Based on these results, the authors named this strain as Stenotrophomonas sp. strain NCTR.

Aquaculture↗
PubMed1996

Detection of Pasteurella pneumotropica in laboratory mice and rats by polymerase chain reaction.

A 16S rDNA-based polymerase chain reaction (PCR) method specific for Pasteurella pneumotropica was developed. The PCR product, a 395-base pair DNA fragment, was amplified from P. pneumotropica and not from 42 other bacterial species tested, including four other Pasteurella species and Actinobacillus ureae. The PCR method was used to identify 13 previously isolated strains that had been identified as P. pneumotropica by conventional methods: 12 were confirmed by PCR; one that was PCR-negative was re-examined by biochemical methods and determined to be A. ureae. The PCR detection of P. pneumotropica in nasopharyngeal swab specimens from 121 surveillance animals (15 inbred mice and 5 inbred rats from 20 animal rooms) had a high carrier state in healthy laboratory animals; for example, rat swab specimens were 89.6% (43/48) positive by PCR, 8.3% were positive by the direct culture-biochemical method, and 16.7% were positive by the enrichment culture-biochemical method. The positive rate for mice (21.9% [16/73]) was lower than that for rats.

Animals↗
PubMedDate not supplied

The prevalence of alcohol abuse and dependence in two geographically distinct regions in Michigan: an UPRNet study.

OBJECTIVE: No definitive studies have been done to determine the frequency of alcohol dependence and abuse in selected sites in Michigan. Because the Upper Peninsula is geographically, economically, and culturally distinct from Lower Michigan there may be an increased prevalence of alcoholism compared to other parts of the state. METHODS: This study compared the responses of 292 Upper Peninsula residents to the responses of 225 lower peninsula residents in the Kalamazoo area on a questionnaire regarding alcohol consumption and health habits. The Revised Health Screening Survey, which has shown adequate validity and reliability for detecting alcohol dependence and abuse, was administered. In the Upper Peninsula each of 12 family practice clinics belonging to UPRNet, a rural primary care research network, were asked to randomly recruit 24 patients to complete the questionnaires. RESULTS: Results showed that the percentage of alcohol dependent subjects in the three Kalamazoo clinics was 16%, while the overall percentage for all UP clinics was 12%. Chi-square analysis indicated no significant differences between the samples. CONCLUSIONS: The widely held belief that people who live in the Upper Peninsula of Michigan have a higher rate of alcohol dependence and abuse than people in other parts of the state was not found to be true in this primary care outpatient population.

Adult↗