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T V Riley

Publications and source records attributed to T V Riley.

At least 19 recordsLinked to original sources
PubMed1992

Infrequency of slime production by urinary isolates of Staphylococcus saprophyticus.

The production of slime by 130 urinary isolates of Staphylococcus saprophyticus, cultured from symptomatic females in the general community, was tested by growing them on Congo red agar. Fourteen of 130 strains (11%) were found to produce slime, 112 strains (86%) did not produce any detectable slime, while four strains (3%) gave an indeterminate result. Slime production does not appear to be an important virulence factor of S. saprophyticus causing urinary tract infection in females of child-bearing age.

Bacteriological Techniques↗
PubMed1992

Ciprofloxacin and Clostridium difficile-associated diarrhoea.

Recent reports have implicated ciprofloxacin as a cause of Clostridium difficile-associated diarrhoea. This problem was examined in three ways. First, the MIC of ciprofloxacin for C. difficile was determined. The MIC range was 8-32 mg/L, with C. difficile were 'treated' with ciprofloxacin and clindamycin in a test-tube, and the growth of C. difficile monitored. The clindamycin-treated emulsions supported growth of C. difficile, while the ciprofloxacin-treated and control emulsions did not differ significantly and failed to support the growth of C. difficile. Finally, 213 patients on ciprofloxacin monotherapy were investigated. Twenty-nine patients were given ciprofloxacin as treatment for diarrhoea, while a further 15 patients developed diarrhoea while being treated. None of these 44 patients harboured C. difficile. Faecal samples from 73 of the remaining 169 patients who did not have or develop diarrhoea were investigated for C. difficile, but none was positive. It was concluded that ciprofloxacin is unlikely to promote C. difficile-associated diarrhoea.

Ciprofloxacin↗
PubMed1992

Selective criteria for the microbiological examination of faecal specimens.

To assess the effectiveness of predetermined investigation criteria for the examination of faecal samples from inpatients, cultured stool specimens were prospectively examined for Salmonella spp, Shigella spp, Campylobacter spp and Clostridium difficile, and screened microscopically for intestinal parasites. Out of a total of 505 specimens, 421 (83%) fulfilled the criteria for examination for C difficile, 254 (50%) for Salmonella spp, Shigella spp, and Campylobacter spp, and 87 (17%) for intestinal parasites. Isolation rates for these organisms in those groups of patients where examination was indicated were 22.5% for C difficile and 9.1% for Salmonella spp, Shigella spp, and Campylobacter spp; the detection rate for parasites was 3.5%. In those patients where the criteria did not suggest investigation, the isolation or detection rates were 3.6% for C difficile, 0% for Salmonella spp, Shigella spp, and Campylobacter spp, and 1.7% for intestinal parasites, suggesting that the use of predetermined investigation criteria was effective.

Animals↗
PubMed1991

Non-radioactive restriction fragment length polymorphism (RFLP) typing of Clostridium difficile.

A typing method for Clostridium difficile based on restriction fragment length polymorphisms (RFLP) is described. The technique utilizes commercially available Escherichia coli ribosomal ribonucleic acid (rRNA) as probe material. Probe labelling, hybridization and detection was performed using the Enhanced Chemiluminescence (ECL) gene detection system. The probe labelling procedure was easy to perform, taking only 20 min. The complete typing method was comparatively simple, reproducible and readily adaptable to most bacterial genera.

Australia↗
PubMed1991

Relapse versus reinfection with Clostridium difficile.

Relapse of Clostridium difficile-associated diarrhoea occurs in 15-20% of patients; however, whether relapse is due to an endogenous source of the organism or reinfection from the environment remains unclear. Restriction enzyme analysis (REA) of chromosomal DNA was used to type multiple isolates from ten patients who had experienced apparent relapses. More than half the relapses were due to infection with a new strain of C. difficile. The remaining patients were infected with the same strain, but whether this strain was acquired from the environment or from endogenous sources could not be determined. Relapses with a different strain of C. difficile could occur if an individual harboured more than one strain in their gastrointestinal tract. To investigate this possibility ten other patients were assessed for carriage of multiple strains. Ten colonies from a primary culture plate from each patient were typed by REA and tested for their ability to produce cytotoxin. All isolates from the same patient were identical by both methods, indicating that multiple carriage of strains may be a rare event.

Adult↗
PubMed1991

Gastrointestinal carriage of Clostridium difficile in cats and dogs attending veterinary clinics.

Cats and dogs being treated at two veterinary clinics were investigated for gastrointestinal carriage of Clostridium difficile using selective solid and enrichment media. Thirty-two (39.5%) of 81 stool samples yielded C. difficile. There were significant differences in isolation rates between clinics, 61.0% of animals being positive at one clinic compared to 17.5% at the other (Chi-square, P less than 0.005). Of 29 animals receiving antibiotics, 15 (52.0%) harboured C. difficile while 11 (23.9%) of 46 animals not receiving antibiotics were positive (Chi-square, P less than 0.01). There was no difference in carriage rate between cats (38.1%) and dogs (40.0%). The environment at both veterinary clinics was surveyed for the presence of C. difficile. Fifteen of 20 sites at one clinic were positive compared to 6 of 14 sites at the other clinic. Both cytotoxigenic and noncytotoxigenic isolates of C. difficile were recovered from animals and environmental sites. These findings suggest that household pets may be a potentially significant reservoir of infection with C. difficile.

Animals↗
PubMed1991

Cell-surface hydrophobicity of Staphylococcus saprophyticus.

The cell-surface hydrophobicity of 100 urinary isolates of Staphylococcus saprophyticus, cultured from symptomatic females in the general population, was assessed using a two-phase aqueous:hydrocarbon system. Relatively strong cell-surface hydrophobicity was exhibited by 79 isolates using the criteria employed, while only 2 of the remaining 21 isolates failed to demonstrate any detectable hydrophobicity. Cell-surface hydrophobicity may be a virulence factor of S. saprophyticus, important in adherence of the organism to uroepithelia. Additionally, the data support the concept that cell-surface hydrophobicity may be a useful predictor of clinical significance of coagulase-negative staphylococci isolated from clinical sources.

Bacterial Adhesion↗
PubMed1991

Susceptibility to desferrioxamine: a new test for the identification of Staphylococcus epidermidis.

The ability to identify Staphylococcus epidermidis quickly and accurately has become increasingly important in clinical microbiology. Susceptibility to desferrioxamine, an iron-chelating agent, was investigated as a new test for the identification of S. epidermidis. All strains of S. epidermidis and S. hominis tested were susceptible to a 1000-micrograms disk of desferrioxamine when grown on brain heart infusion agar. All other strains of coagulase-negative staphylococci, S. aureus and micrococci were resistant. As a single test, susceptibility to desferrioxamine was 96.4% efficient in identifying S. epidermidis; when combined with additional tests such as alkaline phosphatase production and fermentation of trehalose, the efficiency improved to 100%. Desferrioxamine disks were easy to prepare, stable and inexpensive. The test was simple to perform and interpret and should readily find application in clinical microbiology laboratories.

Culture Media↗
PubMed1991

Evaluation of Clinitek 200 and Rapimat II/T for screening for urinary tract infection.

Two machines, the Clinitek 200 and the Rapimat II/T, were evaluated for their ability to screen urine samples for significant bacteriuria and other elements indicative of urinary tract pathology. The automated screening procedures were compared with a conventional approach of microscopy and quantitative culture for 1020 urine specimens obtained from patients in a 700 bed general hospital. When compared with the bacterial culture method both machines gave identical results with a negative predictive value of 0.99, while when compared with microscopy alone the Clinitek 200 and Rapimat II/T gave negative predictive values of 0.92 and 0.87, respectively. It is concluded that both machines would provide cost effective screening of urine specimens.

Adult↗
PubMed1991

Susceptibility of urine isolates of Staphylococcus saprophyticus to antimicrobial agents.

The minimum inhibitory concentrations (MICs) of 10 antimicrobial agents for 96 urinary isolates of Staphylococcus saprophyticus cultured from symptomatic females in the Western Australian general community are reported. All antimicrobial agents tested showed good activity, with the exceptions of norfloxacin (MIC90 8 mg/L) and ampicillin (MIC90 0.5 mg/L). Eighty-three of 96 isolates were susceptible to all antimicrobial agents tested. One isolate was resistant to both tetracycline and trimethoprim. The remainder were resistant to a single antimicrobial agent; 10 to tetracycline and 2 to trimethoprim. None of the isolates exhibited any detectable beta-lactamase activity when tested by the chromogenic cephalosporin method. Synergy between trimethoprim and sulphafurazole against Staph. saprophyticus was demonstrated in only 2 of 5 strains having an increased MIC of one or both of these agents.

Anti-Bacterial Agents↗
PubMed1991

Diarrheal disease due to Clostridium difficile in general practice.

A total of 288 stool samples from patients attending their general practitioners was examined for the presence of Clostridium difficile. C. difficile or its cytotoxin was found in 16 patients (5.5%) and was the most common enteric pathogen detected. Most patients had only mild to moderate diarrhea but in the majority of patients the diarrhea was protracted. Eleven of the 16 patients had received antimicrobial agents in the 3 mths preceding onset of diarrhea and there was good circumstantial evidence that 2 other patients had also been exposed. None of the patients had a history of any inflammatory bowel disease or possible occupational exposure. The prescribing habits of general practitioners with regard to antimicrobial agents were monitored for a 1 yr period. Tetracyclines and amoxycillin accounted for approximately 25% each of all prescriptions dispensed. Ten of the 16 patients were treated with antimicrobials (mainly metronidazole) and in most cases the diarrhea resolved. We conclude that C. difficile may be a significant cause of community-acquired diarrhea.

Adult↗
PubMed1990

Necrobacillosis--primary anaerobic septicaemia due to Fusobacterium necrophorum.

Necrobacillosis is a severe septicaemic illness caused by an anaerobic Gram-negative bacillus, Fusobacterium necrophorum. It occurs predominantly in young people and is characterised by oropharyngeal infection and subsequent metastatic complications, frequently involving the lungs and/or large joints. We report four recent cases in previously healthy young men, describing the clinical features of the disease (including autopsy findings), and the problems associated with diagnosis and treatment.

Adolescent↗
PubMed1989

Extended spectrum cephalosporins and Clostridium difficile.

There is little information about how commonly the newer cephalosporins cause diarrhoea due to Clostridium difficile. In this study of 111 patients with C. difficile-associated diarrhoea, 106 had received antimicrobial agents in the four weeks before detection of C. difficile. The relative risk for each antimicrobial agent was greatest with clindamycin, followed by cefotaxime, cephamandole and ceftriaxone. There was no statistically significant difference in risk between the cephalosporins evaluated. Narrower spectrum penicillins, anti-pseudomonal penicillins and aminoglycosides were not potent inciting agents.

Cephalosporins↗
PubMed1989

A note on susceptibility of Branhamella catarrhalis to heavy metals.

The susceptibility of 56 strains of Branhamella catarrhalis and ten Neisseria spp. to arsenate, silver, nickel, mercury, lead, cadmium, chromium, manganese, iron, cobalt and molybdenum was tested with an agar dilution technique. All but two strains of B. catarrhalis were resistant to multiple metal ions. There were not sufficient differences in susceptibility, however, to allow the development of a typing scheme based on resistograms. Heavy metal resistance in Branhamella was unrelated to beta-lactamase production. Neisseria spp. were more susceptible to metal ions than B. catarrhalis and this may form the basis of a simple diagnostic test.

Drug Resistance, Microbial↗
PubMed1988

Laboratory diagnosis of Clostridium difficile-associated diarrhoea.

This paper reviews the various laboratory procedures available for the isolation and identification of Clostridium difficile and the detection of toxins produced by this organism. Laboratories should be selective in determining which patients require investigation for Clostridium difficile-associated diarrhoea. Transport and storage of stool specimens at 4 degrees C is recommended when delays in processing may occur. Tissue culture techniques are still the best method for detection of cytotoxin and a variety of cell lines can be used. Other methods for detecting cytotoxin, and methods for detecting other toxins are not sufficiently developed yet to warrant introduction into diagnostic laboratories. Culture techniques remain the most sensitive for diagnosis, particularly since the development of a variety of enrichment techniques. Cycloserine cefoxitin fructose agar is still adequate, although reduced concentrations of antimicrobial agents are necessary, and improvements, such as the addition of sodium taurocholate, increase the recovery of spores. Enrichment cultures have markedly increased isolation rates for Clostridium difficile but the significance of these isolates needs to be carefully evaluated. Until simpler and more reliable tests are available in clinical laboratories for the detection of toxins, the isolation of Clostridium difficile from patients with diarrhoeal disease should be considered paramount.

Bacterial Toxins↗