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H Humphreys

Publications and source records attributed to H Humphreys.

At least 37 records · Page 2Linked to original sources
PubMed2004

Positive-pressure isolation and the prevention of invasive aspergillosis. What is the evidence?

Positive-pressure ventilation implies a sealed room, usually with an anteroom to facilitate the donning of protective clothing, airflows of at least 12 air changes per hour and high-efficiency particulate air (HEPA) to prevent infection in susceptible patients. Laminar airflow (LAF) involves much greater air changes, expense and inconvenience to the patient due to noise and draughts. There are few, if any, truly controlled trials on the impact of positive-pressure ventilation and the prevention of invasive aspergillosis (IA); most are observational studies conducted during an outbreak or retrospective analyses of the incidence of IA over periods of time when a variety of preventative interventions were introduced. Therefore, it is often difficult to determine the specific impact of positive-pressure ventilation with HEPA in leading to a reduction in IA. During periods of hospital demolition or construction, HEPA significantly reduces the aspergillus spore counts and in many studies, the incidence of IA, but other measures such as enhanced cleaning, the sealing of windows and the use of prophylactic anti-fungal agents are also important. On balance, the additional expense and inconvenience of LAF does not appear to be justified. Where positive-pressure ventilation is installed, it is imperative that the system be monitored to ensure that the pressure differentials and air changes are appropriate. Whilst there is a role for positive-pressure ventilation in reducing the incidence of IA, we need a better definition of the importance of hospital-acquired IA compared with community-acquired infection and of the relationship between strains of Aspergillus species isolated from the environment and those strains causing infection.

Air Microbiology↗
PubMed2004

Implications of colonization of vancomycin-resistant enterococci (VRE) in renal dialysis patients. Learning to live with it?

Vancomycin-resistant enterococci (VRE) commonly colonize, but less frequently infect, debilitated patients, such as those on chronic renal dialysis. The emergence of VRE amongst our cohort of renal replacement therapy patients posed considerable challenges in our attempts to prevent spread. Although 60 of 451 (13%) patients became colonized, only two patients required systemic antibiotics for confirmed or suspected invasive infection. Mortality and inpatient stay was greater in VRE-positive compared with VRE-negative patients (50% versus 10%) and patients who were screened on three or more occasions were likely to remain positive (e.g. 56% of patients screened on six occasions were positive). The application of recommended guidelines for the control of VRE, however, severely disrupted our renal dialysis programme and therefore had to be abandoned. As patients on renal dialysis are more likely to acquire VRE, remain colonized, require antibiotics and require regular inpatient or outpatient care more frequently than other patients, control measures should be adapted to minimize spread but not disrupt important and essential medical services.

Adolescent↗
PubMed2004

Genetic and phenotypic analysis of biofilm phenotypic variation in multiple Staphylococcus epidermidis isolates.

Production of biofilm in Staphylococcus epidermidis is mediated through enzymes produced by the four-gene operon ica and is subject to phenotypic variation. The purpose of these experiments was to investigate the regulation of ica and icaR transcription in phenotypic variants produced by multiple unrelated isolates of S. epidermidis. Ten isolates were chosen for the study, four of which contained IS256. IS256 mediates a reversible inactivation of ica in approximately 30 % of phenotypic variants. All ten strains produced at least two types of phenotypic variant (intermediate and smooth) in which biofilm formation was significantly impaired. Reversion studies indicated that all phenotypic variants were stable after overnight growth, but began to revert to other phenotypic forms after 5 days of incubation at 37 degrees C. ica transcriptional analysis was performed on phenotypic variants from three IS256-negative isolates; 1457, SE5 and 14765. This analysis demonstrated that ica transcription was significantly reduced in the majority of phenotypic variants, although two variants from SE5 and 1457 produced wild-type quantities of ica transcript. Analysis of seven additional phenotypic variants from SE5 revealed that ica expression was only reduced in three. Expression of icaR transcript was unaffected in all smooth phenotypic variants. Mutations within ica were identified in two SE5 variants with wild-type levels of ica transcription. It is concluded that mutation and transcriptional regulation of ica are the primary mechanisms that govern phenotypic variation of biofilm formation within IS256-negative S. epidermidis.

Bacterial Proteins↗
PubMed2004

Does molecular typing make any contribution to the care of patients with infection?

Molecular typing has been used extensively to study the epidemiology of infection, but there are few studies on the role of typing in the clinical management of infected patients. Examples of this include distinguishing relapse of infection from new infection, determining the significance of colonisation with potential pathogens, assessing the capacity of isolates to spread and cause serious illness, and linking changes in antimicrobial resistance with treatment. Further studies in selected patient groups and greater collaboration between molecular microbiologists, clinical microbiologists and infectious disease physicians are required to determine the impact of molecular typing in these and other scenarios.

Bacteria↗
PubMed2004

Antimicrobial susceptibility of invasive isolates of Streptococcus pneumoniae in Ireland.

Between January 1999 and June 2002, 646 invasive isolates of Streptococcus pneumoniae were collected in Ireland. MICs of penicillin, ciprofloxacin, cefotaxime, moxifloxacin and linezolid were determined by Etest methodology. Eighty-seven (13.5%) isolates showed intermediate resistance to penicillin, while seven (1.1%) showed high-level resistance. Eighty-seven (13.5%) isolates were resistant to erythromycin, but all isolates were susceptible to cefotaxime, moxifloxacin and linezolid. The prevalence of pneumococcal isolates non-susceptible to penicillin in Ireland is worryingly high, but currently there are alternative agents available to treat invasive infection.

Adolescent↗
PubMed2004

An after-hours clinical liaison blood culture service--is it worth it?

The impact of clinical liaison on therapy for positive after-hours blood cultures was evaluated. Of 223 positive blood cultures, no change in management occurred in 164 (73%) cases: 115 positive cultures were regarded as contaminants, and 49 patients were receiving appropriate therapy already. The results of microscopy or culture altered the antimicrobial management of 59 (27%) patients: therapy was altered on the basis of microscopy for 33 patients, and was altered for 26 patients when culture results were available. In total, 94 doses of inappropriate antibiotics were avoided. The main benefit of after-hours blood cultures was that laboratory results were available a day earlier, facilitating timely initiation of appropriate therapy and infection control procedures.

Anti-Bacterial Agents↗
PubMed2003

Epidemiology of MRSA: the North/South study of MRSA in Ireland 1999.

The North/South Study of methicillin-resistant Staphylococcus aureus (MRSA) in Ireland, 1999, includes a joint review of the epidemiology of MRSA across both jurisdictions on the island of Ireland. Data were gathered on all MRSA cases identified in laboratories in Northern Ireland (the North) and in the Republic of Ireland (the South) over a two-week period. The prevalence rate per 100000 population was 11.4 in the North and 14.0 in the South, with a marked variation across geographical regions. MRSA cases were located throughout hospitals and the community, were slightly more common in males than females, and occurred in all age groups, especially in the elderly. The majority of cases were inpatients in acute hospitals and were distributed across all types of wards. Most cases were colonized with MRSA but 5% of cases in the North and 10% in the South had invasive infection. Invasive infection was associated with intravascular lines and invasive procedures/surgery. Continuous surveillance is recommended to monitor the epidemiology of MRSA and the effectiveness of control measures.

Adolescent↗
PubMed2003

Extracorporeal shock wave therapy for plantar fasciitis. A double blind randomised controlled trial.

BACKGROUND: Extracorporeal shock wave therapy (ESWT) is an increasingly popular therapeutic approach in the management of a number of tendinopathies. Benefit has been shown in calcific tendinitis of the rotator cuff, but evidence for its use in non-calcific disorders is limited. AIMS: To perform a double blind randomised controlled trial of moderate dose shock wave therapy in plantar fasciitis. METHODS: Adults with plantar fasciitis for at least 3 months were randomised to receive either active treatment (0.12 mJ/mm(2)) or sham therapy, monthly for 3 months. Pain in the day, nocturnal pain and morning start-up pain were assessed at baseline, before each treatment and 1 and 3 months after completion of therapy. RESULTS: Eighty-eight subjects participated and no differences existed between the groups at baseline. At 3 months, 37% of the subjects in the ESWT group and 24% in the sham group showed a positive response (50% improvement from baseline) with respect to pain. Positive responses in night pain occurred in 41% and 31% in the ESWT and sham groups, respectively. Positive responses in start-up pain occurred in 37% and 36% in the ESWT and sham groups, respectively. Both groups showed significant improvement over the course of the study, but no statistically significant difference existed between the groups with respect to the changes were seen in any of the outcome measures over the 6-month period. CONCLUSIONS: There appears to be no treatment effect of moderate dose ESWT in subjects with plantar fasciitis. Efficacy may be highly dependent upon machine types and treatment protocols. Further research is needed to develop evidence based recommendation for the use ESWT in musculoskeletal complaints.

Adult↗
PubMed2003

A twelve-year review of central nervous system bacterial abscesses; presentation and aetiology.

OBJECTIVES: To review and document the changing patterns in diagnosis, causes and treatment of bacterial infections of the central nervous system (CNS) in a national neurosurgical unit only in patients from whom a specimen was obtained for culture. METHODS: The case notes, radiological results and laboratory records of all 163 patients in our institution who underwent a neurosurgical procedure between 1988 and 2000 for a CNS abscess in a national center were reviewed retrospectively. Those patients from whom there were no operative specimens (i.e. neurosurgical intervention was not performed) and who were treated empirically were excluded, as were patients with mycobacterial infection. RESULTS: The mean age of the 163 patients was 35.2 years. Headache, pyrexia and an altered mental state were the commonest presentations. The frontal lobe was the commonest anatomical site (62 patients, 38%) and the majority of abscesses occurred following community infections such as sinusitis and mastoiditis; no primary source could be identified in 32 (20%) patients. Bacteria were isolated from 73% of patients and polymicrobial infections occurred in 29 (17.7%) patients. Anaerobes accounted for only 13.6% of isolates and methicillin-resistant Staphylococcus aureus (MRSA) was isolated on five occasions, all in the last five years of this review. Sixteen (9.8%) patients died prior to discharge or transfer back to the original referring hospital and 18 (11%) patients developed epilepsy. CONCLUSION: There was a relatively high incidence of polymicrobial infection but the number of specimens with anaerobes was small, which may be because of the use of empiric metronidazole before surgical intervention. Most infections were community-acquired and responded well to a combination of surgical drainage and antibiotic therapy. The emergence of MRSA in this group of patients is, however, worrying.

Adolescent↗
PubMed2003

Control and the prevention of methicillin-resistant Staphylococcus aureus in hospitals in Ireland: North/South Study of MRSA in Ireland 1999.

As part of an all-island survey of methicillin-resistant Staphylococcus aureus (MRSA) in the Republic of Ireland (the South), where there is a mixed public and private healthcare system, and Northern Ireland (the North), where the healthcare system is part of the UK National Health Service, a questionnaire was circulated to all participating hospitals on measures routinely taken to control MRSA. Response rates were 100% in the North and 89% in the South. Over 70% of hospitals screened particular groups of patients on admission to hospital. Ninety-five percent of hospitals in the North and 88% in the South attempted to eradicate MRSA from carriage sites. Most hospitals attempted to isolate or cohort positive patients. About a quarter of hospitals in both parts of Ireland screened new healthcare workers for the presence of MRSA. Terminal decontamination of the environment after the discharge of a patient positive for MRSA was the norm in over 90% of hospitals, however, 6% of hospitals in the South used inappropriate disinfectants for MRSA. All hospitals in the North, but a minority (41%) in the South, had written antibiotic prescribing policies, but only 65% of hospitals in the South had access to an infection control committee, acute hospitals having greater access than district hospitals. The prevention and control of spread of MRSA remains a major challenge in the North and in the South. Although most hospitals in the North and in the South implemented current recommended guidelines on the control of MRSA in hospitals, there was some variability that may be resource related. Policies need to be reviewed in the light of the changing epidemiology of MRSA.

Cross Infection↗
PubMed2003

Penicillin susceptibility and epidemiological typing of invasive pneumococcal isolates in the Republic of Ireland.

A national study was undertaken to investigate the incidence of invasive pneumococcal disease in the Republic of Ireland and to examine the associated isolates. In 1999, 144 S. pneumoniae isolates, all recovered from cases of invasive disease, were received from 12 microbiology laboratories. The incidence of invasive pneumococcal disease was estimated to be 6.6/100000 population. All isolates were analyzed for serotype, penicillin susceptibility, chromosomal relatedness (by using pulsed-field gel electrophoresis [PFGE]), and penicillin-binding protein (pbp) fingerprinting. Several findings of note were observed regarding the pneumococcal population in Ireland. First, isolates of 25 different serotypes were represented, with serotypes 14, 9V, 8, 5, 4, and 3 being the most common. This finding, together with the pbp fingerprinting and PFGE typing results, indicated the clonal spread of strains of these serotypes in Ireland. Second, 27 (18.7%) isolates had reduced susceptibility to penicillin, and 74% of these were serotype 9V. Of these, 80% appeared to belong to the same clone. This could suggest the spread of the international Spanish/French 9V penicillin-resistant clone into Ireland. Third, nine different pbp genotypes were identified, four of which were new. Two pbp genotypes accounted for the majority of isolates dividing them according to their penicillin susceptibility status but irrespective of serotype and PFGE type. This is strong evidence for the occurrence of horizontal transfer of pbp genes between strains, observed with both penicillin-susceptible and penicillin-nonsusceptible isolates. Fourth, there was evidence of serotype transformation since isolates, indistinguishable by pbp fingerprinting and PFGE typing, expressed different capsular types.

Base Sequence↗
PubMed2002

Extracorporeal shock wave therapy for lateral epicondylitis--a double blind randomised controlled trial.

UNLABELLED: Extracorporeal shock wave therapy (ESWT) is an increasingly popular therapeutic approach to the treatment of a number of soft tissue complaints. Whilst benefit has been demonstrated in calcific tendinitis, evidence is lacking for benefit in the management of non-calcific rotator cuff disorders. AIMS: To perform a double-blind placebo controlled trial of moderate dose ESWT in chronic lateral epicondylitis. METHODS: Adults with lateral epicondylitis were randomised to receive either active treatment (1500 pulses ESWT at 0.12 mJ/ mm2) or sham therapy, monthly for three months. All were assessed before each treatment and one month after completion of therapy. Outcome measures consisted of visual analogue scores for pain in the day and at night. RESULTS: Seventy-five subjects participated and there were no significant differences between the two groups at baseline. The mean duration of symptoms was 15.9 and 12 months in the ESWT and sham groups, respectively. Both groups showed significant improvements from two months. No significant difference existed between the groups with respect to the degrees of change in pain scores over the study period. In the ESWT group the mean (SD, range) pain score was 73.4 (14.5, 38-99) at baseline and 47.9 (31.4, 3-100) at three months. In the sham group the mean (SD, range) pain score was 67.2 (21.7, 12-100) at baseline and 51.5 (32.5, 3-100) at three months. At three months, 50% improvement from baseline was noted in 35% of the ESWT group and 34% of the sham group with respect to pain. CONCLUSIONS: There appears to be a significant placebo effect of moderate dose ESWT in subjects with lateral epicondylitis but there is no evidence of added benefit of treatment when compared to sham therapy.

Adult↗
PubMed2002

Operating theatre ventilation standards and the risk of postoperative infection.

Some form of specialized ventilation has been a feature of operating theatres for over 60 years, and ultraclean ventilation has been shown to reduce postoperative infection after prosthetic joint surgery. However, controversy remains over the contribution of plenum (conventional) ventilation to the prevention of infection after surgery in which there is no prosthetic implant. A previous survey in Great Britain and Ireland indicated the continued use of non-ventilated theatres for minor surgery. Laparoscopic and other forms of minimally invasive surgery (MIS) have become more common in the last decade, and offer the advantages of reduced morbidity and shorter hospital stay. However, it is not clear whether such surgery requires the same standard of ventilation facilities as open surgery and, in particular, whether all MIS procedures should be performed in a plenum-ventilated theatre. Furthermore, there are many diagnostic and therapeutic procedures currently performed in cardiac and radiology departments where only natural ventilation is available. The Hospital Infection Society (HIS) Working Party on Infection Control and Operating Theatres is attempting to assess the ventilation facilities currently utilized for a wide variety of MIS procedures. This review should form the basis of future HIS guidance on minimum standards in this area.

Air Pollution, Indoor↗