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Biomedical subjects

H Humphreys

Publications and source records attributed to H Humphreys.

At least 73 records · Page 4Linked to original sources
PubMed1998

Surveillance of an adult intensive care unit for long-term persistence of a multi-resistant strain of Acinetobacter baumannii.

Sporadic infections with Acinetobacter spp., punctuated with prolonged outbreaks of infection involving larger numbers of patients and a particular epidemic strain of Acinetobacter baumannii, have occurred in the adult intensive care unit (ICU) of Nottingham University Hospital since 1985. The aim of this study was to screen patients admitted to the ICU for three or more days during a non-outbreak period in 1994-1995 and to use DNA fingerprinting techniques to compare any isolates of Acinetobacter spp. with isolates obtained from the same ICU during the previous ten years. In the present study, almost 20% of the ICU patients screened during 1994-1995 became colonized with Acinetobacter spp. The commonest species isolated from patients was Acinetobacter baumannii; five different strains were identified by random amplified polymorphic DNA fingerprinting, including the epidemic strain responsible for outbreaks of infection in 1985-1986 and 1992-1993. Environmental sampling yielded Acinetobacter spp. from one or more samples on four occasions; Acinetobacter radioresistens was the commonest species isolated, and Acinetobacter baumannii (not the epidemic strain) was isolated on only one occasion from the environment. The long-term persistence of a potentially epidemic strain in the ICU, even during a non-outbreak period, indicates a need for continued vigilance. Consequently, periodic patient and environmental surveillance, combined with typing of isolates, is recommended for ICUs where significant outbreaks of Acinetobacter infection have occurred in the past.

Acinetobacter↗
PubMed1998

Bacteraemia in the adult intensive care unit of a teaching hospital in Nottingham, UK, 1985-1996.

Bacteraemia is an important cause of morbidity and mortality in the intensive care unit. In this study the distribution of organisms causing bacteraemic episodes in patients in the adult intensive care unit of a large teaching hospital was determined. Particular emphasis was placed on the type of organisms isolated from community- and hospital-acquired bacteraemia, the suspected source of infection, the possible risk factors associated with bacteraemia, and outcome. The incidence of bacteraemia and fungaemia increased from 17.7 per 1000 admissions in 1985 to 80.3 in 1996. A total of 315 episodes of bacteraemia and fungaemia were documented over a 12-year period, of which 18% were considered community-acquired and 82% hospital-acquired. Gram-positive and gram-negative bacteria accounted for 46.9% and 31.5% of the episodes, respectively. Polymicrobial infection accounted for 17.8% and fungi for 3.8% of the episodes. Staphylococcus aureus (22.5%), Staphylococcus epidermidis (7.6%), and Streptococcus pneumoniae (7.9%) were the predominant gram-positive bacteria implicated, whereas Escherichia coli (6%), Enterobacter cloacae (7%), Klebsiella aerogenes (3.8%), Pseudomonas aeruginosa (5.1%), and Acinetobacter spp. (3.8%) were the predominant gram-negative bacteria isolated. The two most common sources of infection were the respiratory tract (39.7%) and an intravascular line (24.5%), but in 8.9% of episodes the focus of infection remained unknown. Bacteraemic patients stayed in the unit for a longer period (12 days) than did non-bacteraemic patients (3 days). The overall mortality related to bacteraemia and candidaemia was 44.4%. Surveillance of bacteraemia in the intensive care unit is important in detecting major changes in aetiology, e.g., the increasing incidence of gram-positive bacteraemia, the emergence of methicillin-resistant Staphylococcus aureus in 1995, and the emergence of Enterobacter cloacae. It is of value in determining empirical antimicrobial therapy to treat presumed infection pending a microbiological diagnosis and in directing the development of guidelines for infection prevention, e.g., guidelines for central venous catheter care.

Adolescent↗
PubMed1998

Monitoring infective complications following hip fracture.

Hip fracture affects more than 55,000 people in the UK each year and this number is increasing. Because of their advanced age and other risk factors, hip fracture patients are at risk of developing infection and a variety of other non-infective complications. Surveillance of superficial wound and deep joint infection is important because of the large number of patients involved and represents a good example of targeted surveillance. Furthermore this may be conducted as part of a quality control programme monitoring other interventions such as prophylaxis for vascular thrombosis. However, to carry this out successfully, a simple but efficient system for recording, collecting and analysing data is required and adequate post-discharge surveillance must be carried out.

Arthroplasty, Replacement, Hip↗
PubMed1998

Development and evaluation of a PCR-based immunoassay for the rapid detection of methicillin-resistant Staphylococcus aureus.

A multiplex polymerase chain reaction (PCR), involving detection of the mecA and femB genes, was combined with a novel immunoassay system capable of detecting specific PCR products. The resulting PCR-immunoassay was evaluated in comparison with conventional microbiological techniques used in the routine diagnostic laboratory for the rapid identification of methicillin-resistant Staphylococcus aureus (MRSA), either in pure culture or in overnight broth cultures obtained following enrichment of patient screening swabs. Among the 480 purified isolates of staphylococci and 246 enrichment broths examined, only one 'false-negative' result was obtained by PCR, compared with 18 'false-negative' results obtained by conventional methodology and demonstrated by further conventional examination. Five demonstrable 'false-positive' results were obtained by conventional methodology, compared with a possible 10 by the PCR-immunoassay, although it was not certain that these 10 PCR results were true 'false positives' as, by definition, MRSA could not be isolated by conventional methodology. The results indicated that the routine diagnostic laboratory was encountering difficulties in identifying MRSA correctly, and that the conventional microbiological techniques lacked sensitivity. Overall, the PCR technique was more accurate and sensitive than conventional methodology in detecting MRSA, and results were available within 24 h of screening swabs arriving in the laboratory, compared with a minimum of 48-72 h by conventional techniques. The immunoassay system added to the usefulness of the method by allowing the detection of specific PCR products within 5 min of completing the PCR, without the normal additional step of agarose gel electrophoresis.

Bacterial Proteins↗
PubMed1997

Sterilization of instruments in general practice: what does it entail?

There is increasing interest amongst general practitioners in carrying out minor surgical procedures but it is unclear what resources are available for this. We decided to assess the level of knowledge of sterilization and the use of benchtop sterilisers in general practice by circulating a postal questionnaire to the 883 general practices in the Trent Regional Health Authority. The response rate was 49%. Minor surgical procedures were performed in 86% of practices but less than half of respondents understood what was meant by sterilization, 28% considered that the floor of the surgery should be disinfected or sterilised and 13% believed that immersion in 2% glutaraldehyde for 10 min constituted sterilization. 93% had a benchtop steriliser, only a quarter kept a log book, and approximately a third had it serviced at intervals of one year or longer. Less than 50% understood the correct position in which a bowl or kidney dish should be placed and 41% had used or had access to a local sterile services department. The concept of sterilization is not clearly understood and the use of benchtop sterilisers in Trent is suboptimal. On-going education of staff in primary care is required and consideration should be given to a system of accreditation.

England↗
PubMed1997

Impact of Acinetobacter spp. in intensive care units in Great Britain and Ireland.

Acinetobacter spp. are of increasing importance as hospital pathogens in intensive care units (ICUs) but it is unclear what clinical impact these bacteria have in Great Britain and Ireland. A survey was carried out by questionnaire on the impact of Acinetobacter in ICUs and the laboratory methods used to identify and type isolates. There were 70 respondents, of whom 25 reported that Acinetobacter had not been recovered from ICU patients within the previous 12 months. The remaining 45 respondents reported that the respiratory tract was the most common site from which these bacteria were isolated, but they were currently endemic in one ICU only. There were considerable differences in methods used to identify Gram-negative bacilli recovered from ICU patients, which may partly explain differences in the reported prevalence of isolates between centres, and 12 laboratories attempted to type isolates by a range of techniques. The availability and use of agreed antibiotic policies specific for ICUs may be particularly important in prevention and control where infection with Acinetobacter is prevalent.

Acinetobacter↗
PubMed1997

Methicillin-resistant Staphylococcus aureus (MRSA)--a re-appraisal of control measures in the light of changing circumstances.

Methicillin-resistant Staphylococcus aureus (MRSA) remains an important nosocomial pathogen and the number of affected patients is rising. Increasing numbers of patients at risk of acquisition, inadequate isolation facilities, problems in identifying the source of outbreaks and the perception amongst some clinical colleagues that control measures are too disruptive have contributed to the problems faced by infection control teams. Recent controlled studies indicate that MRSA is no less virulent than sensitive strains and emphasize the continuing need for control measures even where MRSA is endemic. Efforts to control spread should be targeted to key clinical areas, such as intensive care units, where the impact of infection is likely to be greatest, whilst general infection control measures should be strengthened throughout the hospital.

Cross Infection↗
PubMed1997

Peptic ulcer bleeding in the elderly: relative roles of Helicobacter pylori and non-steroidal anti-inflammatory drugs.

BACKGROUND: Most ulcers are caused, one can deduce, by Helicobacter pylori or by use of non-steroidal anti-inflammatory drugs (NSAIDs). Whether both together are worse than one alone is something that is quite unknown. AIM: To study both factors in order to see wither they interact together positively. METHOD: A case control study of ulcer bleeding in elderly patients chosen without weeding. RESULTS: NSAID usage increased risk substantially. So did H pylori infection (but relative risk less than three). Neither seemed to interact. Their actions were discretely intact. CONCLUSION: H pylori effects ulcer bleeding in an adverse manner but does not make the risk of NSAIDs worse.

Aged↗
PubMed1996

Once-daily gentamicin: translating theory into practice.

Gentamicin continues to have an important role in the treatment of serious bacterial infections. There is increasing interest in once-daily administration, which is more convenient than multiple-dose regimens. Animals studies and clinical trials suggest that once-daily administration is as efficacious and no more toxic for a variety of infections, but there is still some reluctance to use once-daily regimens routinely in neutropenic patients, because of the potential risk of breakthrough bacteraemia. A number of aspects of the serum concentration monitoring of once-daily gentamicin remain unresolved. The most commonly used assay systems are not sensitive enough, without some modification in technique, to detect the very small pre-dose concentrations seen with once-daily dosing, and it is not clear what constitutes an acceptable pre-dose concentration. Until the results from further studies become available, it is prudent to maintain a pre-dose concentration below 1 mg.1(-1), and local arrangements are necessary to address the frequency and timing of assays. It seems likely that once-daily administration will become the norm, because of its many advantages.

Animals↗
PubMed1996

Is Burkholderia (Pseudomonas) cepacia disseminated from cystic fibrosis patients during physiotherapy?

Burkholderia cepacia is well recognized as a potential respiratory pathogen in cystic fibrosis (CF) patients and there is increasing concern about nosocomial acquisition. Environmental contamination with B. cepacia before, during and after physiotherapy was studied in eight adult CF patients. Air was sampled using a surface air sampler, and horizontal surfaces and pillows were sampled with moistened swabs and contact plates, respectively. Thirty-nine (40%) of 97 air samples were positive and counts ranged from 1-63 cfu/m3. Forty-four percent of samples taken after physiotherapy were positive. B. cepacia was not recovered from sinks or horizontal surfaces but the pillows of three patients were positive. B. cepacia is disseminated into the immediate environment by adult CF patients receiving physiotherapy. The potential risk of person-to-person transmission during hospitalization justifies the recommendation that B. cepacia-positive patients should be segregated from other CF patients.

Adult↗
PubMed1996

Clinical features of patients with beta-lactamase producing Haemophilus influenzae isolated from sputum.

Ampicillin resistance amongst isolates of Haemophilus influenzae is of increasing concern but its clinical impact is unclear. We performed a retrospective study of 34 hospital patients with lower respiratory tract infection (LRTI) caused by beta-lactamase positive (beta+) H. influenzae and compared these with 34 control patients with LRTI caused by beta-lactamase negative (beta-) strains. Chronic obstructive pulmonary disease was the most common underlying condition in both groups (beta+ 23/24, beta- 25/34). A recent course of antibiotics, especially ampicillin/amoxycillin, was significantly (P < 0.05) more common in the beta+ group (beta+ 17/34, beta- 3/34). Other pathogens were isolated more frequently in the beta+ group (beta+ 10/34, beta- 4/34). There was no difference in outcome between the two groups.

Adult↗