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R R Marples

Publications and source records attributed to R R Marples.

At least 19 recordsLinked to original sources
PubMed1992

Methicillin-resistant Staphylococcus aureus in England and Wales.

Methicillin-resistant Staphylococcus aureus (MRSA) were detected soon after the introduction of methicillin in 1960, and reports of their isolation increased up to 1971. Changes in antibiotic usage were associated with a fall and then, in the early 1980s, a further rise in the number of reports. This article reviews the various surveys that have been conducted to establish the frequency, distribution and strain varieties of MRSA. The first strain to be recognised as epidemic (ie, affecting more than one hospital), was defined by phage typing and antibiogram, confirmed with molecular typing, and designated EMRSA-1. It was first detected in 1981 and became progressively more widespread until it began to decline in 1987. Only three health regions reported this strain in the first quarter of 1991. EMRSA-2 has remained restricted to the South East and South West Thames regions. EMRSA-3 appeared in the South East Thames region in 1987 and has since spread, being reported from eight health regions in the first quarter of 1991. At least 11 other strains of MRSA affecting more than one hospital have been detected and ten endemic strains (restricted to single hospitals) have been identified. Imported strains of MRSA, often introduced following the repatriation of road traffic accident victims, may include strains with epidemic potential and local spread has followed importation in at least two incidents. Continued surveillance of epidemic MRSA strains and the search for simple and widely applicable markers, such as unusual antibiotic resistance patterns or biochemical features, are needed for the prompt application of control measures.

Aged↗
PubMed1992

An epidemic methicillin-resistant strain of Staphylococcus aureus in Spain.

During 1990, a strain of methicillin-resistant Staphylococcus aureus became epidemic in Spain and spread in a manner analogous to that of EMRSA-1 in England. Isolates of this strain produced little protein A and were resistant to a number of antibiotics including ciprofloxacin. Beta-lactamase production was encoded by a c. 39 kb plasmid, which also conferred resistance to mercury, cadmium, ethidium bromide and propamidine isethionate. Investigation showed that two variants, separable by supplementary and Fisk phage typing, were circulating. The B variant appeared to spread more readily than the A variant. The opportunity was taken to compare the discriminatory power of traditional typing methods with molecular techniques. The discriminatory power of the molecular techniques used only reached the same level as the traditional methods when double enzyme digestion of total cellular DNA by EcoR I and Cla I was performed.

Bacterial Typing Techniques↗
PubMed1992

Evaluation of methods for typing coagulase-negative staphylococci.

One hundred and forty-two coagulase-negative staphylococci (CNS) isolated from dialysate effluent or skin of patients receiving continuous ambulatory peritoneal dialysis (CAPD) were typed by extended antibiogram (16 antibiotics) and biotype (26 reactions). These isolates were then typed by supplementary methods to determine the most suitable typing method for an epidemiological study of antibiotic resistance. These included phage typing, reverse phage typing, plasmid typing, whole-cell protein typing by SDS-PAGE with analysis by densitometry, and immunoblotting. The percentage of isolates typed successfully by the supplementary methods were: phage typing 20%, reverse phage typing 0%, plasmid typing 66%, SDS-PAGE 100%, immunoblotting 100%. The discrimination of each method was: phage typing 20%, plasmid typing 37%, SDS-PAGE 69%, immunoblotting 57%. Reproducibility was 88% for phage typing and 97% for plasmid typing. The reproducibility of the whole-cell protein typing was 83% if the same extracts were used but only 43% when separate protein extracts were analysed on separate occasions. However, strain relatedness was highly reproducible. The determination of an antibiogram-biotype profile was not a sufficiently accurate typing method for an epidemiological study of antibiotic resistance. Whole-cell protein typing by SDS-PAGE or immunoblotting was technically demanding but was the most effective of the supplementary methods for detecting erroneous discrimination and false matching produced by antibiogram-biotype combinations.

Bacterial Proteins↗
PubMed1991

Surveillance of methicillin-resistant Staphylococcus aureus in England and Wales, 1986-1990.

The incidence of methicillin-resistant Staphylococcus aureus in England and Wales was monitored by a weekly reporting scheme from early 1986 to March 1990. Potential coverage was approximately two-thirds of hospital beds. Reporting centres fell from a peak of 210 in 1986 to a low of 101 centres early in 1989 with later recovery. There were 2367 positive reports in 1986, 2174 in 1987, 1700 in 1988, 1701 in 1989 and 632 in the first quarter of 1990. Colonizations outnumbered infections by 2:1. There were marked regional differences: North-East Thames was dominant in 1986 and 1987, and then declined; South-East Thames showed a dramatic increase in 1988 which continued. Other regions showed less significant changes but there were continuing problems in the South-Western Region and in the West Midlands. Some of these changes were related to the decline of EMRSA-1, possibly due to the introduction of effective control measures, and to the emergence of EMRSA-3 in South-East Thames and its spread to Wessex.

Bacteriophage Typing↗
PubMed1990

A survey of methicillin-resistant Staphylococcus aureus affecting patients in England and Wales.

For a six-month period between October 1987 and March 1988, 660 isolates of methicillin-resistant Staphylococcus aureus (MRSA) from 570 patients were sent to the Staphylococcus Reference Laboratory at Colindale to supplement the National reporting survey of MRSA in England and Wales. The isolates were characterized by phage typing, antibiotic susceptibility and by selected biochemical tests. Patient details were also surveyed. Fourteen strains affected more than one hospital and were called multi-hospital epidemic strains. One strain, EMRSA-1, accounted for more than 40% of isolates and of patients. Other epidemic strains were defined. Ten additional strains were restricted to single hospitals. Only 25 primary isolates were non-typable but 67 sporadic typable strains occurred. The patients affected were approximately equally either infected or colonized. The sexes were represented equally. Orthopaedic and geriatric wards were over-represented. Epidemic strains were clumping factor positive while some sporadic strains were weak producers. Urea alkalinization and protein A production could supplement phage typing and antibiotic resistance in strain recognition.

Adult↗
PubMed1990

Beta-lactamase-negative, methicillin-resistant Staphylococcus aureus in a newborn nursery: report of an outbreak and laboratory investigations.

An outbreak of skin infection caused by a beta-lactamase-negative strain of methicillin-resistant Staphylococcus aureus (MRSA) occurred during a five-week period in a newborn nursery. Twelve babies, two mothers and two members of staff were involved. One baby had a diagnosis of staphylococcal scalded skin syndrome and two others required treatment with antibiotics. The infecting strain produced exfoliative toxin A. It was thought that it had been introduced from a different maternity unit by a nasal carrier. Laboratory investigations tended to support this hypothesis.

Bacteriophage Typing↗
PubMed1990

International collaborative evaluation of the ATB 32 staph gallery for identification of the Staphylococcus species.

This international collaborative study evaluates a new system (ATB 32 Staph) for the identification of staphylococci taking into account the new novobiocin-sensitive and -resistant species reported. This study involved eight laboratories and 792 strains were tested. The reproducibility obtained for the cumulative results of the inter- and intra-laboratory tests was more than 90%. For 713 strains relevant of a species 95.5% were correctly identified by the system. Eight strains (1.2%) were misidentified and 24 strains (3.3%) were not identified. For 79 strains initially considered as not-classified, 62% were identified at the species level by the new system. The newer ATB 32 Staph gallery is a performant and useful method for routine identification of the currently described staphylococci species from clinical and animal origin.

Animals↗
PubMed1989

A laboratory-confirmed outbreak of rifampicin-methicillin resistant Staphylococcus aureus (RMRSA) in a newborn nursery.

The routine laboratory monitoring of methicillin-resistant strains of Staphylococcus aureus (MRSA) at a large teaching hospital led to the detection of a new, multiply-resistant strain of MRSA, which was resistant not only to penicillin, oxacillin, methicillin, cephamandole, erythromycin, tetracycline, kanamycin and gentamicin but also to rifampicin and sulphamethoxazole-trimethoprim. The rifampicin-methicillin resistant strain of S. aureus (RMRSA) was first detected in blood cultures of babies from the newborn nursery. A bacteriological investigation of the nursery revealed the source to be a paediatric medical officer who was colonised with the resistant strain, and who at the time was receiving rifampicin for pulmonary tuberculosis. The rifampicin resistance was presumably acquired during rifampicin therapy. The outbreak in the nursery was brought to an abrupt end by treatment of the colonised medical officer with mupirocin, applied nasally twice a day for a week, and by the introduction of standard infection-control measures. Reference laboratory assistance was needed to confirm the initial assumption that the outbreak was caused by a single strain.

Bacterial Typing Techniques↗
PubMed1989

The evaluation of a typing scheme for coagulase-negative staphylococci suitable for epidemiological studies.

A typing scheme was devised for an epidemiological study of infection with coagulase-negative staphylococci in patients undergoing continuous ambulatory peritoneal dialysis (CAPD). The scheme was constructed in four stages suitable for the screening of large numbers of isolates: antibiogram, biotype, phage type, and plasmid profile. The discrimination and reproducibility of the scheme was established by the examination of 50 isolates from 33 consecutive episodes of peritonitis affecting 18 patients. The discrimination of the scheme was 76%, with a reproducibility of 86%. Indistinguishable strains occurred in individual patients only, demonstrating that no cross-infection between patients occurred during the 10-month period of collection of strains, and suggesting that the discriminating power of the scheme was, in fact, much higher. The antibiogram, selected as the first stage of the scheme because it was the simplest and cheapest test, proved to be the most discriminatory stage, providing 60% of the final discriminatory power.

Anti-Bacterial Agents↗
PubMed1989

The epidemiology of peritonitis caused by coagulase-negative staphylococci in continuous ambulatory peritoneal dialysis.

The epidemiology of 10 episodes of CAPD peritonitis caused by coagulase-negative staphylococci was studied. The infecting micro-organism was found in prospective skin swabs in six episodes, widely distributed and as the predominant, or equally predominant, organism at each site but was not detected in swabs taken more than 12 weeks before the episode of peritonitis; this suggests recent acquisition. Infecting strains were no more likely to be adherent or to produce slime than non-infecting strains, nor had they any other characteristic detected in our typing scheme that might lead to their detection before peritonitis developed.

Bacterial Adhesion↗
PubMed1988

Complex typing of methicillin-resistant Staphylococcus aureus (MRSA).

To discriminate between methicillin-resistant Staphylococcus aureus from 5 nosocomial outbreaks and from sporadic nosocomial infections, the efficacy of a complex typing scheme by phage typing, biochemical typing, resistance phenotype, plasmid profiles, plasmid patterns and attribution of resistance determinants to the chromosome was studied. In addition to the International Basic Set and experimental phages 88-93, 10 experimental phages from the Public Health Laboratory Service, Colindale, London, were used for phage-typing. The 10 experimental phages from PHLS in particular, in combination with plasmid profiles and plasmid patterns, were of special discriminative value.

Bacterial Typing Techniques↗
PubMed1988

Supplementary phages for the investigation of strains of methicillin-resistant Staphylococcus aureus.

Nineteen experimental phages were derived by mitomycin-C induction from methicillin-resistant strains of Staphylococcus aureus collected world-wide. They were assessed for their ability to distinguish isolates of a methicillin-resistant strain of S. aureus epidemic in the London area from other British strains, both sensitive and resistant to methicillin. The experimental phages were most active against strains of phage groups III and I + III. One phage was related to the phages of lytic group I. A typing pattern common to isolates of the epidemic strain was identified and used as an aid in the recognition of this strain. Ten of the phages were retained for further study.

Bacteriophage Typing↗