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Biomedical subjects

P M Shanahan

Publications and source records attributed to P M Shanahan.

14 recordsLinked to original sources
PubMed2000

Characterization of multi-drug resistant Salmonella typhi isolated from Pakistan.

Thirty-nine strains of Salmonella typhi, isolated in 1995 from four Districts in Pakistan, Rawalpindi, Islamabad, Kharian and Jehlem, were catalogued and examined. Chromosomal DNA from each isolate was digested with XbaI restriction endonuclease and subjected to pulsed-field gel electrophoresis. Three clonal variants comprising of 17-19 DNA fragments were identified. Antibiotic susceptibility testing identified that 37 of the S. typhi were resistant to chloramphenicol, trimethoprim and ampicillin. These antibiotic resistance genes were found to be located on one of four plasmids belonging to incompatibility group IncHI1 and ranging in size from 150-175 Kb. The genes responsible for this resistance in each case were the chloramphenicol acetyltransferase (CAT) type I, the dihydrofolate reductase (DHFR) type VII and the beta-lactamase TEM-1 respectively.

Bacterial Typing Techniques↗
PubMed1998

Molecular analysis of and identification of antibiotic resistance genes in clinical isolates of Salmonella typhi from India.

A representative sample of 21 Salmonella typhi strains isolated from cultures of blood from patients at the Christian Medical College and Hospital, Vellore, India, were tested for their susceptibilities to various antimicrobial agents. Eleven of the S. typhi strains possessed resistance to chloramphenicol (256 mg/liter), trimethoprim (64 mg/liter), and amoxicillin (>128 mg/liter), while four of the isolates were resistant to each of these agents except for amoxicillin. Six of the isolates were completely sensitive to all of the antimicrobial agents tested. All the S. typhi isolates were susceptible to cephalosporin agents, gentamicin, amoxicillin plus clavulanic acid, and imipenem. The antibiotic resistance determinants in each S. typhi isolate were encoded by one of four plasmid types. Plasmid-mediated antibiotic resistance genes were identified with specific probes in hybridization experiments; the genes responsible for chloramphenicol, trimethoprim, and ampicillin resistance were chloramphenicol acetyltransferase type I, dihydrofolate reductase type VII, and TEM-1 beta-lactamase, respectively. Pulsed-field gel electrophoresis analysis of XbaI-generated genomic restriction fragments identified a single distinct profile (18 DNA fragments) for all of the resistant isolates. In comparison, six profiles, different from each other and from the resistance profile, were recognized among the sensitive isolates. It appears that a single strain containing a plasmid conferring multidrug-resistance has emerged within the S. typhi bacterial population in Vellore and has been able to adapt to and survive the challenge of antibiotics as they are introduced into clinical medicine.

Chloramphenicol O-Acetyltransferase↗
PubMed1996

Mutations responsible for reduced susceptibility to 4-quinolones in clinical isolates of multi-resistant Salmonella typhi in India.

Twelve isolates of Salmonella typhi isolated in Vellore, India had reduced susceptibility to 4-quinolones (MIC of ciprofloxacin 0.256 mg/L). One isolate was isolated in 1992 but the remaining 11 were isolated in 1994. The section of the gyrA gene from codons 24 to 185, which includes the "Quinolone Resistance Determining Region", was amplified by the polymerase chain reaction and, after separating the amplified strands, the DNA was sequenced directly. In the one isolate from 1992, no alterations were seen in this region of gyrA, compared with the ciprofloxacin-sensitive isolates and presumably decreased 4-quinolone susceptibility resulted from reduced permeability of the cell outer membrane or another mechanism. In nine isolates from 1994, a substitution of phenylalanine for serine at position 83 of GyrA correlated with the decrease in 4-quinolone susceptibility. In the remaining two isolates, the novel substitution of aspartate to tyrosine at position 87 was found; in one isolate this substitution was coupled with another substitution at position 83 but in the other it was not.

Amino Acid Sequence↗
PubMed1995

Beta-lactam resistance in normal faecal flora from South Africa.

The genetic and biochemical basis of ampicillin resistance amongst the aerobic Gram-negative commensal faecal flora of healthy volunteers in South Africa has been determined. Amongst 608 ampicillin resistant strains isolated from 320 of the participants, 158 were able to transfer their ampicillin resistant determinants into Escherichia coli K-12 J62-2. Iso-electric focusing of the beta-lactamases, extracted from the transconjugants, demonstrated that ampicillin resistance resulted from the presence of the TEM-1, TEM-2 and SHV-1 beta-lactamases in 94.3%, 2.5% and 3.2% of isolates respectively. Endonuclease restriction digests of the plasmids isolated from the transconjugants showed that the beta-lactamase genes were present on a wide variety of plasmid types; 101 distinct plasmid endonuclease restriction patterns were identified. Transferable ampicillin resistance was associated with resistance to other antibiotics at the following frequencies: trimethoprim (48.7%), streptomycin (35.4%), tetracycline (27.2%), spectinomycin (9.5%), chloramphenicol (3.2%) and gentamicin (1.3%). One antibiotic resistance pattern, ampicillin and trimethoprim, predominated (28%). In total, 77.9% of the plasmids conferred resistance to other antibiotics raising the possibility that use of any of these agents, not simply ampicillin, may contribute to the maintenance of resistance genes.

Adolescent↗
PubMed1994

Beta-lactam resistance in aerobic faecal flora from general practice patients in the UK.

One hundred faecal specimens submitted to a diagnostic laboratory in Edinburgh and found to be negative for gastrointestinal pathogens were examined for the presence of antibiotic-resistant bacteria. The results were compared with findings in the healthy population in the same area. The highest incidence of resistance was observed to cefuroxime (65%) and ampicillin (60%). Of the ampicillin-resistant isolates, 62% could transfer their resistance determinants to a standard Escherichia coli host strain. In 100% of these transconjugants ampicillin resistance was shown to result from the presence of the TEM-1 beta-lactamase which was identified in a heterogeneity of plasmid profiles. These plasmids commonly mediated resistance to streptomycin and tetracycline in addition to ampicillin.

Ampicillin Resistance↗
PubMed1993

The prevalence of antimicrobial resistance in human faecal flora in South Africa.

Between January and March 1992, 361 faecal specimens were collected from the healthy black population in the Transvaal Province of South Africa. Each specimen was examined for the prevalence of antimicrobial resistance in commensal bacteria. Volunteers, from both rural and urban dwellings, were divided into four age groups. The overall carriage rate of resistance varied from 88.6% for ampicillin, 74.2% for trimethoprim, 52.6% for chloramphenicol, 10.2% for nalidixic acid to 7.5% for gentamicin. The carriage of resistance found to each individual antimicrobial agent was slightly higher in the rural population rather than the urban population but there was no correlation between the prevalence of antimicrobial resistance and the age group.

Adolescent↗
PubMed1984

Older alcoholics: professional, family education programs aid treatment.

The identification and treatment of older alcoholics often are complicated by negative stereotypes and inaccurate information about the aging process. these misconceptions may result from incomplete statistical data, lack of attention to the subjects of alcoholism and aging in medical and gerontological journals, disagreement concerning the disease's origin and treatment, and conflict over whether to differentiate between alcoholism and alcohol abuse. In recent professional literature, however, some of these concerns are being addressed. A wider dissemination of information is essential for health professionals as well as for alcoholics and their families. Both groups must understand the changes associated with aging so that existing programs for alcoholism treatment can be adapted to serve the elderly. Results of an informed, enlightened attitude toward older alcoholics would be: Awareness that alcoholism--at any age--is a treatable disease; Increased attention to the special communication and mobility needs of the elderly; Availability of printed and audiovisual materials about aging and alcoholism in locations where older adults gather; and The training of family members and health care workers in alcoholism identification and intervention.

Aged↗
PubMed1976

Methodology for teaching theory in occupational therapy basic professional education.

This article proposes a methodology for teaching theoretical concepts to undergraduate occupational therapy students. The methodology is based upon a learning theory and three conceptual models of psychosocial dysfunction. It is suggested that such a method will help students to understand theoretical principles and to develop the ability to apply these principles to treatment. This method has been used successfully by the authors in classroom instruction.

Humans↗