Search PubMed⌕ Search

Biomedical subjects

B D Cookson

Publications and source records attributed to B D Cookson.

At least 73 records · Page 4Linked to original sources
PubMed1992

Screening for Corynebacterium diphtheriae.

A throat swab from a 9 year old girl with pharyngitis yielded a non-toxigenic strain of Corynebacterium diphtheriae var mitis and Streptococcus group G. C pseudodiphtheriticum was isolated from the throats of two of her four brothers. In each case the isolate was sent to the reference laboratory before full identification. The growth was found to be mixed for one brother; the other isolate being a toxin producing C diphtheriae var gravis. The child was asymptomatic and the case proves that all colonial types on the Hoyles plate should be identified.

Child↗
PubMed1992

The epidemiology of ciprofloxacin resistance in coagulase-negative staphylococci in CAPD patients.

Ciprofloxacin was used as empirical therapy for peritonitis in patients receiving continuous ambulatory peritoneal dialysis (CAPD) for 26 months, providing an opportunity to study the epidemiology of ciprofloxacin resistance amongst coagulase-negative staphylococci (CNS). Swabs were collected from the CAPD patients, staff, and clinic environment before, during and after the time this antibiotic was prescribed. Clinical isolates were also studied, and records kept of patient hospital attendance. Ciprofloxacin-resistant staphylococci were typed by antibiogram, biotype, plasmid profile, SDS-PAGE, and immunoblotting. No resistant strains were detected before the use of ciprofloxacin. During its use 30% of patients became skin carriers, and resistant strains caused 8% of peritonitis episodes in 7% of patients (38% of carriers). Resistant strains were isolated from the environment, but never from attending members of staff. A total of 208 resistant isolates with MIC's between 8 and 128 mg/l was collected and identified as Staphylococcus epidermidis or S. haemolyticus. Sixteen strain types were distinguished. There was epidemiological evidence for selection of resistant strains derived from the host commensal flora and also for cross-colonization, and cross-infection. Carriage of resistant strains fell to 15% of patients, 6 months after the use of ciprofloxacin had ceased.

Air Microbiology↗
PubMed1991

Inter-strain comparison by pyrolysis mass spectrometry in the investigation of Staphylococcus aureus nosocomial infection.

Pyrolysis mass spectrometry (PyMS) was used to examine isolates of Staphylococcus aureus from an outbreak of wound infections on a cardiothoracic surgical unit, some of which were thought to have been related to a point-source in the operating theatre. The PyMS results were compared with the results of phage typing. Both methods suggested that a single strain of S. aureus, of phage pattern 29/52/52A/79/80/81, was responsible for some of the wound infections, but PyMS also identified two patients with phage non-typable isolates. Phage typing indicated four staff members as possible carriers of the epidemic strain, but PyMS indicated only two. Epidemiological enquiry confirmed that one of the two members of staff identified by both methods was likely to have been the source of the theatre-based infection. PyMS is a rapid and relatively inexpensive technique for the investigation of nosocomial S. aureus infection and was more discriminatory than phage typing in this instance.

Carrier State↗
PubMed1991

Chlorhexidine resistance in methicillin-resistant Staphylococcus aureus or just an elevated MIC? An in vitro and in vivo assessment.

Chlorhexidine (Hibiscrub; ICI) is generally accepted to be effective as an antiseptic hand wash for methicillin-susceptible Staphylococcus aureus (MSSA), but there is dispute whether the chlorhexidine MIC for methicillin-resistant S. aureus (MRSA) strains is higher than that for MSSA strains and, indeed, whether it is relevant. In addition, the link between resistance to chlorhexidine, gentamicin, and "nucleic acid-binding" compounds (NAB; which code, in particular, for propamidine isethionate and ethidium bromide) requires clarification. We performed chlorhexidine MIC and rate of kill tests on a number of MSSA and MRSA isolates. Two gentamicin-resistant MRSA isolates without NAB plasmids were more susceptible (0.25 and 0.5 microgram/ml) than four of eight MSSA that we tested (range, 0.25 to 2 microgram/ml). Chlorhexidine MICs were higher (4 to 8 micrograms/ml) for seven distinct MRSA isolates with plasmids conveying resistance to gentamicin and NAB (GNAB). Curing of the GNAB plasmid from MRSA strains resulted in a fall in the MIC (1 to 3.3 micrograms/ml), but no consistent fall in killing by chlorhexidine was observed. No effect on the chlorhexidine MIC or killing was observed when we cured strains of methicillin resistance. GNAB plasmid transfer resulted in a rise in the chlorhexidine MIC for the strains but not consistent fall in killing by chlorhexidine. Ethical approval was granted for 10 volunteers to each have a methicillin-susceptible, GNAB-resistant, derived transcipient and its GNAB-susceptible isogenic parent applied to separate sites in an in vivo skin test; no significant difference was seen in survival rates after the application of chlorhexidine. These results suggest that chlorhexidine appears to be as effective as a hand-washing agent for MRSA isolates with or with out NAB plasmids as it is for MSSA isolates.

Chlorhexidine↗
PubMed1989

Numerical analysis of electrophoretic protein patterns of methicillin-resistant strains of Staphylococcus aureus.

A total of 50 strains of Staphylococcus aureus, including 41 methicillin-resistant S. aureus (MRSA) strains, were characterized by one-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis of whole-cell proteins. The protein patterns contained 40-50 discrete bands and were highly reproducible. Partial patterns were used as the basis of a computer-assisted numerical analysis. The MRSA strains clustered into four phenons at the 83% similarity level; and further division of phenon 1, at the 86% similarity level, resulted in a total of six clusters. All of the MRSA isolates from an MRSA epidemic in the United Kingdom were found to cluster in phenon 1 together with 9 of the 12 MRSA isolates from eastern Australia and 3 other MRSA isolates from the United Kingdom. The remaining three eastern Australian isolates clustered separately in phenon 2. Phenon 3 appeared to be exclusive to strains that were both susceptible and resistant to methicillin and that reacted with group V phages, and phenon 4 comprised 11 isolates, all of which were other MRSA isolates from the United Kingdom. We conclude that computer-assisted numerical analysis by high-resolution sodium dodecyl sulfate-polyacrylamide gel electrophoresis of whole-cell proteins provides additional criteria for the study of the epidemiology and the evolution of MRSA.

Bacterial Proteins↗
PubMed1988

'Cialit' as a tissue preservative: a microbiological assessment.

We describe bacterial contamination of a 'Cialit'-preserved cartilage bank which continued after a variety of changes to the harvesting and preservation protocols during a 3-year prospective study. Our results emphasize the importance of adequate tissue bank microbiological screening. Alternative methods of tissue preservation should be considered.

Bacteria↗
PubMed1988

Epidemic methicillin-resistant Staphylococcus aureus.

We contrast the experiences, in our Health Authority in South-East London, with the particular epidemic methicillin-resistant Staphylococcus aureus (the EMRSA) strain that has recently spread widely around London and South-East England, and with the other MRSA (OMRSA) strains encountered there. Our isolates of the EMRSA were identical by chromosomal restriction enzyme analysis, and the chromosomal and plasmid phenotypes were similar to those described in North London and Eastern Australia. Experimental phage-typing distinguished them from OMRSA encountered in 1984 to 1986. Between 1984 and 1985, the EMRSA caused increased infection and patient colonization compared to the years 1969 to 1983. A change in infection control procedures was usually required to control the EMRSA and in 1986 isolates had returned to their pre-1984 levels. Between 1984 and 1986 OMRSA were still encountered, but did not spread or require changes in infection control procedures. The distribution of other resistant isolates was examined; c 94% of neomycin-resistant isolates were in-patients or clinic patients. Forty-five different phage-type/antibiogram patterns were found in 88 isolates from 66 patients between 1982 and 1985, and patient clusters were uncommon. The ability of the EMRSA to spread is discussed and is probably not purely organism related. Our experience supports the contention that some MRSA are truly epidemic, whilst others do not behave in this manner.

Humans↗
PubMed1985

Mycobacterium szulgai--a case of cutaneous infection?

An infant presented with a carbuncle over the angle of her jaw which grew a scotochromogenic mycobacterium, subsequently identified as Mycobacterium szulgai. The problems of identification of this organism and its possible pathogenic role are outlined.

Chromatography, Thin Layer↗