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Biomedical subjects

H Humphreys

Publications and source records attributed to H Humphreys.

At least 55 records · Page 3Linked to original sources
PubMed2002

MRSA bacteraemia: North/South Study of MRSA in Ireland 1999.

Retrospective aggregate data on all Staphylococcus aureus isolates recovered from blood cultures during 1998 were collected in both jurisdictions on the island of Ireland, Northern Ireland (North) and the Republic of Ireland (South), as part of the North/South Study of MRSA in Ireland 1999. A postal questionnaire was used to gather the data, and all diagnostic microbiology laboratories in the North and 98% of laboratories in the South participated. S. aureus bacteraemia occurred at rates of 20.4 per 100,000 population in the North and 24.5 per 100,000 in the South (missing data from one laboratory). In the North, 22% of patients who had blood cultures positive for S. aureus had methicillin-resistant S. aureus (MRSA) and 25% of S. aureus isolates were MRSA (some patients had more than one isolate). In the South, 31% of patients who had blood cultures positive for S. aureus had MRSA and 36% of S. aureus isolates were MRSA. There was a marked variation in rates between different regions. The percentage of patients with blood cultures positive for S. aureus that had MRSA was considerably lower in the North (22%) than in the South (31%), and in both jurisdictions was lower than that found in England and Wales in 1999 (37%). It is recommended that data on S. aureus bacteraemia and methicillin-resistance rates (already available in many laboratories) are gathered at regional and national level for the surveillance of antimicrobial resistance.

Bacteremia↗
PubMed2002

A UK historical perspective on operating theatre ventilation.

As part of the preparation for the report of the Hospital Infection Society Working Party on Infection Control and Operating Theatres, studies published from the UK on the subject of operating theatre ventilation were reviewed. Few have convincingly demonstrated a direct relationship between the microbiological quality of operating theatre air and postoperative wound infection. Nevertheless, the findings from these studies have had a major influence on the development of official UK guidance on the design, performance and testing of ventilation in both conventional and ultraclean operating theatres.

Air Microbiology↗
PubMed2002

Environmental regulation of biofilm formation in intensive care unit isolates of Staphylococcus epidermidis.

Staphylococcus epidermidis is a common cause of prosthetic device-related infection in the intensive care unit (ICU). The environmentally regulated ica operon encodes a polysaccharide adhesin which is a key virulence determinant in the development of S. epidermidis biofilms. To evaluate the capacity of ICU S. epidermidis isolates to form biofilm, we measured biofilm production by 18 isolates associated with device-related infection and 20 contaminating isolates that were not associated with clinically diagnosed infection. Biofilm assays were performed in brain-heart infusion (BHI) medium and in BHI supplemented with salt, ethanol or subinhibitory tetracycline, all of which have the potential to promote biofilm formation. Polymerase chain reaction (PCR) was used to screen for the presence of the ica genes. A significant proportion of S. epidermidis strains associated with device-related infections (89%) were found to contain the ica locus compared with 50% of contaminating isolates (P = 0.01). However only four of 26 (15.3%) of all ica-positive isolates were biofilm-positive when grown in BHI medium, indicating that no significant association existed between the presence of the ica locus and biofilm-forming capacity, under standard growth conditions. In contrast the number of ica-positive isolates that were biofilm-positive under stress-inducing growth conditions or in the presence of subinhibitory tetracycline increased significantly to 73% (P = 0.02). These findings suggest that the presence of the ica locus alone is not sufficient for biofilm formation and that regulation of biofilm formation under altered growth conditions, which may exist in the in vivo environment, also plays a possible role in the pathogenesis of biomaterial-related S. epidermidis infections.

Biofilms↗
PubMed2002

Methicillin-resistant Staphylococcus aureus: laboratory detection methods in use in the Republic of Ireland and Northern Ireland.

There is no universally agreed laboratory protocol for the detection of methicillin-resistant Staphylococcus aureus (MRSA) and hence a variety of approaches are used. As part of an all-island survey of MRSA in the Republic of Ireland (the South) and Northern Ireland (the North), a questionnaire was circulated to 14 participating laboratories in the North and 49 in the South, to determine the methods used to isolate MRSA from clinical specimens, identify S. aureus and test for susceptibility to methicillin. Almost two-thirds (64%) of laboratories in the North but only 16% of laboratories in the South use enrichment culture. There is heavy reliance on commercial kits to confirm the identification of S. aureus in the South but all laboratories in the North use the staphylocoagulase test. More than 90% of all laboratories use a disc method for susceptibility testing and 71% of laboratories in the North supplement this with the E-test; however, a range of methicillin disk concentrations are in use. There is a need to review current laboratory methods used to detect MRSA, with follow-up audit on their implementation. Additional resources may be needed in some laboratories to comply with revised guidelines, and reference facilities are required to assess new commercially available techniques and to confirm the identification of unusual or difficult strains.

Bacterial Typing Techniques↗
PubMed2002

Extracorporeal shock-wave therapy for tendonitis of the rotator cuff. A double-blind, randomised, controlled trial.

We have performed a double-blind placebo-controlled trial of moderate doses of extracorporeal shock-wave therapy (ESWT) for non-calcific tendonitis of the rotator cuff. Adults (74) with chronic tendonitis of the rotator cuff were randomised to receive either active (1500 pulses ESWT at 0.12 mJ/mm2) or sham treatment, monthly for three months. All were assessed before each treatment, and at one and three months after the completion of treatment. The outcome was measured with regard to pain in the shoulder, including a visual analogue score for night pain, and a disability index. There were no significant differences between the two groups before treatment. The mean duration of symptoms in both groups was 23.3 months. Both showed significant and sustained improvements from two months onwards. There was no significant difference between them with respect to change in the Shoulder Pain and Disability Index (SPADI) scores or night pain over the six-month period. A mean (+/-SD; range) change in SPADI of 16.1 +/- 27.2 (0 to 82) in the treatment group and 24.3 +/- 24.8 (-11 to 83) in the sham group was noted at three months. At six months the mean changes were 28.4 +/- 25.9 (-24 to 69) and 30.4 +/- 31.2 (-12 to 88), respectively. Similar results were noted for night pain. We conclude that there is a significant and sustained placebo effect after moderate doses of ESWT in patients with non-calcific tendonitis of the rotator cuff, but there is no evidence of added benefit when compared with sham treatment.

Adult↗
PubMed2001

Surveillance of hospital-acquired infection in the Republic of Ireland: past, present and future.

There is increasing interest in the surveillance of hospital-acquired infection (HAI) in the Republic of Ireland due to a greater awareness of the consequences of antibiotic resistance, and consumer pressure in the form of public expectations of the quality of health care. To date there have been no nationwide prospective surveillance projects but surveillance has taken place in the form of participation in international and national studies, and the description of local outbreaks. Infection control teams and others have participated in projects such as a European study of HAI in intensive care units conducted in 1992, the second national prevalence study conducted in the UK in 1993 and two surveys of methicillin-resistant Staphylococcus aureus (MRSA) carried out in 1995 and 1999, the latter involving colleagues in Northern Ireland. There have been a number of local surveys of antibiotic-resistant bacteria including the molecular characterization of MRSA in Dublin hospitals, vancomycin-resistant enterococci, and Gram-negative bacteria such as Enterobacter spp. and Serratia spp. affecting compromised patients such as bone marrow transplant recipients. In the future, it is hoped to standardize case definitions, automate data entry, increase collaboration with surveillance initiatives in Northern Ireland and link in with European networks such as EARSS and HELICS. Apart from the need to improve the quality of health care in Irish hospitals, approximate costings suggest that there are potential savings of 7.5 pounds sterling -15 pounds sterling m to be made following a reduction of HAI rates of 15%.

Cross Infection↗
PubMed2000

Intensive care unit design and environmental factors in the acquisition of infection.

The incidence of infection in the intensive care unit (ICU) is one of the highest in the hospital and yet facilities to prevent infection are often inadequate in this important clinical area. Many antibiotic-resistant bacteria such as methicillin-resistant Staphylococcus aureus (MRSA), Serratia marcescens and vancomycin-resistant enterococci (VRE), may survive and persist in the environment leading to recurrent outbreaks. A number of professional and scientific bodies in the UK, the USA and Europe have published guidelines on the design and layout of ICUs. All emphasize the importance of adequate isolation facilities (at least one cubicle for every six beds), sufficient space around each bed (20 m2), wash hand basins between every other bed, ventilation including positive and negative pressure ventilation for high risk patients and sufficient storage and utility space. Common sense and considerations of safety and comfort should guide decisions on floors, walls etc. Appropriate cleaning and disinfection programmes are essential to render the ICU relatively pathogen free and compliance with handwashing is imperative in minimizing infection in this high-risk area. Infection control teams should support ICU personnel in their efforts to upgrade facilities and help ensure that this is a priority when resources are limited.

Cross Infection↗
PubMed1999

Molecular and antibiogram relationships of Acinetobacter isolates from two contrasting hospitals in the United Kingdom and South Africa.

The aim of this study was to compare the molecular relationships and antibiograms of nosocomial isolates of Acinetobacter spp. from two acute-care hospitals in Nottingham, UK, and Soweto, South Africa, with different hospital infection control problems and procedures. In contrast to Nottingham, where randomly amplified polymorphic DNA fingerprinting demonstrated that a single multiresistant strain of Acinetobacter baumannii has predominated in the hospital intensive care unit over an 11-year period, the Soweto isolates formed a heterogeneous group of unrelated molecular clusters of different antibiograms, with numerous different strains of Acinetobacter baumannii, Acinetobacter sp. 3 and Acinetobacter sp. 13TU apparently being endemic throughout the Soweto hospital. The contrasting results illustrate the need to maintain exemplary infection control procedures in hospitals where high standards have been achieved and warn of what might result if such measures are diminished.

Acinetobacter↗