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Biomedical subjects

B Cryan

Publications and source records attributed to B Cryan.

At least 19 recordsLinked to original sources
PubMed1998

Epidemiology and clinical impact of Pseudomonas aeruginosa infection in cystic fibrosis using AP-PCR fingerprinting.

Arbitrarily primed PCR (AP-PCR) was utilized to genetically fingerprint 252 Pseudomonas aeruginosa strains isolated from the sputa of 50 cystic fibrosis (CF) patients attending the Cork CF clinic over a period of 3 years. Ten distinct P. aeruginosa strains were identified and the distribution, temporal trends and clinical impact of colonization with these individual P. aeruginosa clones was studied. A number of random isolates from each AP-PCR group were analysed using pulsed field gel electrophoresis (PFGE) in order to confirm the discriminatory power of the AP-PCR technique. The majority of patients were colonized with a single strain over the time period of the study, but it was also possible to harbour two or more strains transiently or simultaneously. Four main strains were relatively evenly distributed throughout the CF population, and it was noted that patients from the same family or attending the same school tended to harbour the same P. aeruginosa clone. Disease severity was significantly associated with the age of the patient (P < 0.001), clearly indicating an increase in severity with increase in age. The general clinical status of the CF patients was not significantly associated with the P. aeruginosa variant isolated from their sputa. Lung status was defined by FEV1 measurement and chest X-ray score (CXR). The non parametric Kruskal-Wallis significance test of FEV1, CXR and age by colonizing P. aeruginosa clone indicated that FEV1 (P = 0.017), but not CXR (P = 0.19) or age (P = 0.842), differed significantly across the clones of P. aeruginosa isolated. Patients harbouring P. aeruginosa strains B, F or G clearly had lower FEV1 scores while those harbouring clones A, C, D or H generally had higher FEV1 scores. Thus, the sub-species variant of P. aeruginosa colonizing CF patients may be associated with the severity of progressive lung disease.

Adult↗
PubMed1998

Actinomyces pyogenes septic arthritis in a diabetic farmer.

We report a case of septic arthritis and osteomyelitis of the left ankle due to Actinomyces pyogenes in a diabetic farmer. Few confirmed human cases of A. pyogenes infection have been reported, partly because of inadequate identification of this bacterium. Bacteriological characteristics of the organism, which resembles Arcanobacterium haemolyticum, are described with a review of previous case reports.

Animals↗
PubMed1997

Investigation of a methicillin-resistant Staphylococcus aureus (MRSA) outbreak in an Irish hospital: triplex PCR and DNA amplification fingerprinting.

Methicillin-resistant Staphylococcus aureus (MRSA) is becoming a problematic nosocomial pathogen. A continuing increase in numbers of isolates is reported from Irish hospitals each year. Preventing cross-infection and the further spread of endemic strains requires effective control measures. This necessitates the development of sensitive methods for both detection and genetic identification of MRSA isolates. In this study, 48 MRSA strains isolated in the Cork University Hospital were analysed between January and July 1995 using a one-tube triplex-polymerase chain reaction (PCR), wherein three genes, the methicillin-resistance gene (mecA), femA and the extracellular thermonuclease gene, nuc, were simultaneously amplified. Methicillin-sensitive S. aureus (MSSA) and coagulase-negative staphylococci (CNS) were also tested and the assay was found to be MRSA specific. The genetic relationship among this collection of MRSA isolates was also investigated. A single primer, RW3A, derived from a well-characterized, repetitive sequence found in Mycoplasma pneumoniae produced discriminating DNA fragment arrays with all the study organisms. The patterns were reproducible, even after several passages of the isolates. Quantitative analysis of the patterns divided the collection into two main groups, DAF group I representing 48% of the collection and DAF group II a further 19%. The remaining strains showed unrelated patterns. To fully outline the distribution of MRSA in this area a larger study will be necessary. This paper outlines the applicability of both the identification and fingerprinting techniques to local strains.

Cross Infection↗
PubMed1996

Tuberculosis due to Mycobacterium bovis in humans in the south-west region of Ireland: is there a relationship with infection prevalence in cattle?

OBJECTIVE: To compare the incidence of tuberculosis due to Mycobacterium bovis in humans to the prevalence of M. bovis infection in cattle in south-west Ireland and discuss possible links between them. SETTING: In the south-west region of Ireland, a mixed urban and rural community (pop. 536,000), there is a residuum of human tuberculosis caused by M. bovis. METHODS: A retrospective analysis of the incidence of culture-positive M. bovis disease in humans in south-west Ireland from 1983 to 1994 and of the results of tuberculin testing in cattle from 1978 to 1994 for the same region. RESULTS: One to five cases of human tuberculosis due to M. bovis were recorded per year while the overall prevalence of bovine infection fell gradually during the period of study from 467 tuberculin-positive animals per 100,000 cattle tested in 1983 to 158 per 100,000 in 1994. CONCLUSION: The low incidence plateau of human tuberculosis due to M. bovis together with the decline in prevalence of animal infection in the overall period studied suggest a cut-off in the animal to human chain of infection at two points; the animal source and the ingestion of (now pasteurized) milk. This would suggest that disease in humans is now due to reactivation of previous foci of infection which were acquired when milk pasteurization was not compulsory. Based on this, we would anticipate a further reduction and possible elimination of human tuberculosis due to M. bovis in this region in the next 10-15 years.

Animals↗
PubMed1996

Susceptibility to varicella zoster virus infection in health care workers.

Varicella zoster virus (VZV) is an occupational hazard for a percentage of health care staff. Nine hundred and seventy staff members attending the Occupational Health Department at Cork University Hospital took part in the survey. A latex agglutination assay was used to determine the health care workers immune status to VZV. Of the 970 workers tested, 928 (95.7%) were immune to VZV. The sensitivity, specificity and predictive value of an enquiry regarding a history of chicken-pox was determined on a sample of 206 health care workers. The positive predictive value was 95% (119/125) and the negative predictive value was 11% (4/35). The sensitivity of the enquiry was 79% (119/150), the specificity was 40% (4/10), reducing to 61% (119/195) and 36% (4/11) respectively when individuals with uncertain histories were included in the calculations. The advantages and disadvantages of selective staff screening are discussed. In the authors' opinion all health care workers involved in the clinical care of patients should be screened by serology for past VZV infection before taking up duty and those who are susceptible to VZV should be made aware of the risks and health effects associated with VZV if contracted.

Adult↗
PubMed1995

Genomic fingerprinting Acinetobacter baumannii: amplification of multiple inter-repetitive extragenic palindromic sequences.

Acinetobacter species are important nosocomial pathogens. A rapid and sensitive identification system, capable of providing strain identity at the genetic level, is required to identify outbreak strains and facilitate the early implementation of infection control procedures. Repetitive extragenic palindromic (REP) elements, have been identified in numerous bacteria and these genomic sequences provide useful targets for DNA amplification. A method for amplifying inter-REP DNA sequences, REP-multiple arbitrary amplicon profiling (REP-MAAP), is described and applied to 29 Acinetobacter baumannii from clinical samples. Amplified polymorphic DNA patterns were demonstrated for all isolates and those displaying identical REP-MAAP patterns were considered identical at the genetic level. In the spring of 1993, 10 intensive care unit patients had endotracheal colonization with A. baumannii (five with REP-MAAP I and five with REP-MAAP II patterns). These findings suggested nosocomial transmission of organisms which was terminated by standard infection control measures. No further A. baumannii were detected until the winter of 1993 when isolates of different REP-MAAP groups emerged, suggesting that factors other than nosocomial transmission were implicated.

Acinetobacter↗
PubMed1995

Isolation of Mycobacterium chelonae in a bronchoscopy unit and its subsequent eradication.

SETTING: Contamination events with Mycobacterium chelonae in 7 patients undergoing bronchoscopy, out of a total of 100 patients in a 5-month period, were analysed. OBJECTIVE: To identify and assess the importance of factors thought to be relevant in the aetiology of these contamination events and by removing these factors, to eradicate the problem of continuing M. chelonae contamination. DESIGN: A retrospective analysis of the frequency of M. chelonae isolates from bronchoalveolar fluid, assessing the contribution of the following measures to the eradication of M. chelonae: (1) changes to the bronchoscopy unit's water supply; (2) insertion of bacterial filters; (3) installation of a new semi-automated cleaning machine incorporating an ultrasound cycle; (4) staff training in correct use of the new equipment. RESULTS: Following the discontinuation of using tapwater in the cleaning process, the above changes resulted in complete eradication of contamination events, with no further events occurring in the following 12 months. CONCLUSION: Insertion of bacterial filters into the water supply, with the addition of a more sophisticated semi-automatic cleaning machine involving an ultrasound cycle in addition to conventional cleaning methods currently used, will help reduce or eradicate contamination events with M. chelonae in bronchoscopy units.

Adult↗
PubMed1995

Colorimetric detection of heat-labile toxin-encoding gene of enterotoxigenic Escherichia coli by PCR.

In the developing world, enterotoxigenic Escherichia coli (ETEC) strains which produce enterotoxins are a significant cause of morbidity and mortality. Heat-labile (LT) toxin PCR detection methods have been described, but they have limited applications in a routine laboratory setting. A colorimetric DNA method for the rapid amplification and detection of the LT toxin gene in ETEC strains is described. Target amplification together with colorimetric detection would overcome many of the limitations of conventional PCR. This paper describes a colorimetric PCR detection method specific for LT-gene-encoding ETEC strains. DNA was extracted from two representative colonies from each bacterial isolate and amplified by PCR. Digoxigenin was incorporated into the amplification product, permitting a one-step direct detection using anti-digoxigenin alkaline phosphatase-conjugated antibody. This technique was applied to the investigation of 70 E. coli isolates derived from clinical fecal samples obtained from an Irish population. Eleven percent of the samples were LT positive, confirming the applicability of this method. All LT-positive ETEC strains (controls and clinical isolates) were detected, and no false-positive results occurred.

Bacterial Toxins↗
PubMed1995

Detection of the heat-stable toxin coding gene (ST-gene) in enterotoxigenic Escherichia coli: development of a colour amplified PCR detection system.

Screening biological samples using the polymerase chain reaction (PCR) has obvious advantages compared with current molecular analytical methods based on gel electrophoresis and/or hybridisation, both of which are expensive and time-consuming, therefore the development of a PCR assay format that is applicable to large sample numbers and that can readily use equipment commonly found in diagnostic laboratories would be advantageous. This report describes the development of a colour amplified PCR detection system which is simple in design and could be universally applied to the detection of any DNA template. As an example, the system has been applied in the detection of the heat-stable toxin coding gene (ST-gene) from enterotoxigenic Escherichia coli (ETEC). The assay is sensitive, detecting 10 fg of a purified DNA template and 270 cfu of an ST-gene-positive ETEC strain.

Bacterial Toxins↗
PubMed1994

Bacterial translocation during peroperative colonic lavage of the obstructed rat colon.

Peroperative antegrade colonic lavage is often performed before primary anastomosis in emergency colonic surgery. The influence of colonic lavage on bacterial translocation from the obstructed colon was determined. Forty female Wistar rats were studied in four groups: (1) control; (2) non-obstructed with lavage; (3) obstructed; and (4) obstructed with lavage. Ligature obstruction of the rectum was performed in groups 3 and 4. Some 4 days later 35S-radiolabelled Escherichia coli was inoculated into the colon of all animals. Groups 2 and 4 underwent colonic lavage. Lavage in the group 4 animals with left-sided colonic obstruction significantly increased the levels of E. coli in regional nodes, liver, spleen, lung, kidney and blood (as assessed by organ culture and scintillation counting) compared with those in groups 1, 2 and 3 (P < 0.05). These results suggest that peroperative lavage of the obstructed colon significantly increases the level of bacterial translocation.

Anastomosis, Surgical↗
PubMed1992

Isolation of Campylobacter sputorum biovar sputorum from an axillary abscess.

Campylobacter sputorum biovar sputorum is a rarely isolated organism, particularly from human clinical specimens. Its pathogenic potential is unknown. We present here what we believe to be the first report of this organism being isolated from a clinically significant source, an axillary abscess. To our knowledge, this organism has not been reported previously as one of clinical relevance in the U.K.

Abscess↗
PubMed1992

Lyme disease in Ireland.

The data pertaining to Irish specimens sent to the Lyme disease Laboratory at Charing Cross Hospital since 1986 is presented and discussed. In the period up to June 1990, 484 specimens were tested, 14% of these were positive by enzyme linked immunosorbent assay or indirect immunofluorescent assay. Only 13 of these were confirmed as positive by immunoblotting.

Adult↗