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Biomedical subjects

M Farrington

Publications and source records attributed to M Farrington.

At least 19 recordsLinked to original sources
PubMed2000

Effects on nursing workload of different methicillin-resistant Staphylococcus aureus (MRSA) control strategies.

Nursing staff workload may influence hospital-acquired staphylococcal transmission. Closure of wards to new admissions is used in some institutions as part of methicillin-resistant Staphylococcus aureus (MRSA) outbreak control, and we postulated that it worked by reducing staff workload, allowing more time for good infection control practices. We have used the GRASPCopyright workload system to compare nursing workload during six MRSA outbreaks. Two outbreaks occurred while an aggressive control policy ('old'; 1994-1995) was in place, with a low threshold for ward closure. Control measures had been relaxed before the later four outbreaks, with wards remaining fully or partially open unless MRSA transmission proved intractable ('new'; 1995-1996). To standardize the analysis we compared GRASP and epidemiological data for periods while MRSA transmission was occurring on each ward ('during'), and four week periods 'before' and 'after'. Closing wards to admissions reduces staff workload towards a quality environment, although the nursing requirements of remaining patient rises. Workload pressures may rise during outbreaks if wards are not closed quickly and fully, and patients are not transferred to specialist isolation facilities. Changes in nursing workload need to be assessed during comparative studies of outbreak control measures and the GRASP(c) system appears to be a sensitive way to measure these.

Cross Infection↗
PubMed1999

Controlling MRSA.

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Cross Infection↗
PubMed1999

Pre-transplantation testing: who, when and why?

An ever-widening range of human organs and tissues is being transplanted, limited currently only by the ingenuity of surgeons and immunologists to overcome the physical and immune barriers. Microbiologists are in danger of being left behind. Although the major infective risks of human organ transplantation are now well understood, many details remain controversial, and the special risks associated with tissue banking have received little attention until recently. What should we do? Are we making mountains out of molehills? Are there any data on which to base a rational decision? Topics covered include: bacteriology of cadaveric heart valve transplantation (why are valves not cultured and only dunked in antibiotic solution for 24h, whereas endocarditis gets treated for 4 weeks?); screening for tissue-born viruses (why does everyone persist with serology when genomic methods are so much better?); screening organ donors for CMV (surely we should use the optimally sensitive combination of methods?); peripheral blood stem cell transplants (should we culture these, and what do the positive results mean if we do?); donor sputum screening before heart-lung transplantation (does this aid the post-operative management of the recipient?). With active participation from the floor some areas of consensus were identified and topics worthy of scientific investigation in the future were highlighted.

Heart Valves↗
PubMed1998

Microbiological monitoring of bone grafts: two years' experience at a tissue bank.

In the first two years of operation of a tissue bank, bone was processed on 63 occasions from 22 cadaveric donors and on 37 occasions from 185 living donors. A standardized protocol for microbiological sampling, culturing and interpretation of the results was developed. Semi-quantitative culture of washings of bone was performed on receipt by the tissue bank, and broth enrichment cultures of bone samples were performed at the end of processing, and again after irradiation. One bone donation was rejected because of heavy contamination with Klebsiella sp. on receipt, and contamination of six donations with Burkholderia cepacia was shown to have come from a water deionizer. Contamination of bone on receipt by the tissue bank decreased during the study period, probably related to increasing experience of staff harvesting bone. Microbiological surveillance of bone grafts protect recipients from infection, and is useful as a quality control of the process of bone banking.

Bone Banks↗
PubMed1998

Winning the battle but losing the war: methicillin-resistant Staphylococcus aureus (MRSA) infection at a teaching hospital.

A methicillin-resistant Staphylococcus aureus (MRSA) control policy, aimed at eradication, was established at a 1000-bed hospital in 1985, applied consistently for 10.5 years, and then relaxed. Its components included screening of high-risk patients, transfer of carriers to exhaust-ventilated isolation rooms, closure of wards to new admissions when local transmission was detected, MRSA screening during outbreaks, and prospective collection of clinical and epidemiological information. During the eradication policy period, every 6 months, a mean of 5.1 patients (range 1-12) already carrying MRSA were admitted, and a mean of 3.6 (range 0-16) acquired carriage in the hospital. The largest outbreak comprised 11 patients despite epidemic MRSA strain EMRSA-16 being introduced six times, and MRSA did not become endemic. MRSA-positive admissions increased progressively from 1993; nursing staff workload increased, areas available for alternative patient accommodation were reduced, the resulting ward closures interfered with clinical services, and hence the control policy was relaxed in mid-1995. Isolation facilities were overwhelmed with 622 new patient-isolates in the next 18 months, and there were 67 clinical infections in 1996. The proportion of blood cultures positive for MRSA rose nearly sevenfold by 1996 and 27-fold by 1997. Thus, repeated eradication of MRSA, even epidemic strains, by use of a stringent policy, is possible given sufficient resources, whereas flexible national guidelines designed to control, but not eradicate, epidemic staphylococci, are currently unlikely to be successful. The costs of eradication policies need to be weighed against those of endemicity.

Cross Infection↗
PubMed1997

Dispose of disposables?

We investigated the implications of a change from disposable to regular crockery and cutlery, and the installation of a dishwasher on a 12-bedded-infectious diseases ward. A limited microbiological study of used disposable cutlery revealed contamination by methicillin-resistant Staphylococcus aureus of one utensil out of 12. Changing to conventional utensils could be recommended if a dishwasher meeting DHSS requirements was installed and safe working practices introduced.

Cooking and Eating Utensils↗
PubMed1996

Bone graft contamination from a water de-ionizer during processing in a bone bank.

An organism resembling Burkholderia (formerly Pseudomonas) cepacia was isolated from cultures taken during processing of six bone grafts. The source of the contamination was traced to a water de-ionizer; the problem had begun when procedures had been changed, so that water from the de-ionizer had been used without sterilization. Cultures of bone for grafting not only protect recipients from infection, but act also as useful controls for processes involved in bone banking.

Bone Banks↗
PubMed1996

Bacterial contamination of peripheral blood progenitor cells for transplantation.

Peripheral blood progenitor cells (PBPC) were obtained from 128 apheresis harvests on 64 patients and were tested in duplicate for microbiological contamination (1) after collection and (2) after thawing, following processing and cryopreservation. In this study we have attempted to improve the monitoring of contamination in peripheral blood progenitor cell collections by identifying exogenous contamination that probably originated from the testing laboratory and is therefore not clinically significant. We found no contamination in 82% of harvests, 1.6% of harvests to be significantly contaminated and organisms were isolated from 16.4% that were assessed as clinically nonsignificant. Our experience indicates that the choice of microbiological methods will influence the results and their clinical relevance. No samples were positive by direct culture. We recommend that sampling should be performed at more than one stage during the procedure and that initially only the post-thaw samples be analysed. Testing should be performed by enrichment culture in duplicate only and if positive to aid interpretation the post-collection sample should then be cultured. No patient given nonsignificantly contaminated graft without antibiotic cover suffered infection from the identified organism. The incidence of significant contamination was low and we recommend that in these cases PBPC grafts can be infused safely provided prophylactic antibiotic cover is given.

Bacteriological Techniques↗
PubMed1995

'Fifteen percent of microbiology reports are wrong!': further experience with an internal quality assessment and audit scheme.

Infection control teams critically depend on the quality of the diagnostic microbiology laboratories with which they are associated. Internal quality assessment (IQA) by specimen resubmission measures the consistency of laboratory performance and can be adapted for medical audit, but few laboratories appear to include these techniques as part of their quality control procedures. We established an IQA scheme in our bacteriology laboratory in May 1989, and the mean discrepancy rate for the first two years was nearly 15%. During the next two years covered by this report, the scheme was extended to include audit of the consistency of medical microbiologists' comments on reports, and a standardized scoring scheme was introduced. Results from the scheme are collated and analysed thrice yearly, and laboratory techniques altered and extra staff training planned to reduce discrepancies. Four thousand four hundred and fourteen specimens (1.4% workload) were resubmitted, and 325 (7.4%) gave discrepant results. During the two years, the overall discrepancy rate fell consistently from 9.4 to 3.2%. Fifty-three discrepancies (1.2%) were in microscopy, and 243 (5.5%) were between culture results. Substantial decreases in technical discrepancies followed training initiatives in sputum bacteriology, and training in anaerobic recognition and improved illumination in the anaerobic cabinet. Problems of consistent recognition of staphylococci and of urine isolates in mixed culture, and of faecal microscopy have proved difficult to eradicate. There was a 20.3% discrepancy rate between medical comments, but only 0.4% would have been likely to result in different patient outcomes. The cost of running the scheme was 4474 pounds per annum, equating to a surcharge of 0.058 pounds to each of our routine diagnostic specimens.(ABSTRACT TRUNCATED AT 250 WORDS)

Diagnostic Errors↗
PubMed1995

Patterns of Cryptosporidium antigen and oocyst excretion in calves studied by reverse passive haemagglutination and light microscopy.

A reverse passive haemagglutination (RPH) assay incorporating a monoclonal antibody against Cryptosporidium parvum oocysts was used to follow Cryptosporidium coproantigen excretion by calves. RPH detected soluble antigen that passed 0.22 micron filters. Non-specific reactions that occurred in some samples were markedly reduced by heat treatment of the faecal specimens and were abolished by filtration after heat treatment. Results were compared with oocyst counts performed by microscopy of modified Ziehl-Neelsen (MZN) stained faecal smears. Five hundred and thirty-two daily specimens were examined from 30 calves. The mean age at which positive results for both oocysts and antigen was detected was 9 days (range 5-15 days), and excretion lasted for 5-11 days with some cycling of positive reactions in some calves. The occasional cycling to a negative reaction demonstrates a need to take samples from consecutive days to ensure diagnosis. Two hundred and ninety-one (54.7%) specimens were negative in both tests, 178 (33.5%) were positive in both, 14 (2.6%) were positive only by microscopy, and 49 (9.2%) were positive only by RPH. By these criteria the kappa coefficient of agreement between the tests was good (0.753). Compared with MZN, the sensitivity of RPH is 92.7%, specificity 85.6%, positive predictive value 78.4% and negative predictive value 95.4%. The method is simple, objective, has ease of quality control, and either single samples or batches can be processed.

Aging↗
PubMed1995

A scale for identifying "Stockholm syndrome" reactions in young dating women: factor structure, reliability, and validity.

The factor structure, reliability, and validity of a 49-item scale designed to measure Stockholm Syndrome (also referred to as "traumatic bonding" and "terror bonding"), that is, bonding with an abusive partner, were assessed for college women in heterosexual dating relationships. Factor analysis identified three major factors: Core Stockholm Syndrome, characterized by cognitive distortions and other strategies for coping with abuse; Psychological Damage, marked by depression, low self-esteem, and loss of sense of self; and Love-Dependence, typified by the feeling that one cannot survive without one's partner's love. The scale and factors had excellent internal consistency and good test-retest reliabilities. They correlated negatively with the Marlowe-Crowne Social Desirability scale and positively with Horowitz, Wilner, & Alvarez' (1979) Impact of Event Scale, Hyler and Rieder's (1987) Borderline Personality Disorder Scale, Hatfield and Sprecher's (1986) Passionate Love Scale, and Straus' (1979) Verbal Aggression and Violence scales of the Conflict Tactics Scales.

Adaptation, Psychological↗
PubMed1995

Anaesthetic drugs and bacterial contamination.

We investigated the bacterial contamination of commonly used intravenous anaesthetic agents. Ten trainee anaesthetists drew up four syringes each of propofol, midazolam, thiopentone, 0.9% saline and a culture medium control using their normal practice. A set of syringes was cultured at the time of drawing up and at 2, 4 and 8 h afterwards. No anaesthetist washed his or her hands before drawing up the drugs. Six anaesthetists capped the syringes using sheathed needles. Eight syringes were contaminated with bacteria. Coagulase-negative staphylococci were isolated from six syringes (four sheathed and two unsheathed) and an Acinetobacter sp. from two syringes (one sheathed and one unsheathed). No bacteria were cultured from the midazolam syringes. However, two syringes from each of the other solutions were contaminated. This implies that one syringe was contaminated when it was drawn up, at 2 h a further two had detectable contamination, two more were contaminated at 4 h and three more at 8 h. We cannot recommend drawing up drugs at the start of a list for use later in the day. They should be used immediately after drawing up. Basic hand washing before drawing up drugs may reduce contamination.

Anesthetics, Intravenous↗
PubMed1994

The morphological development of the inferior colliculus in a marsupial, the Northern quoll (Dasyurus hallucatus).

As a part of a project concerning the development of hearing, some features of the morphological development of the inferior colliculus were studied in a marsupial, the Northern quoll or native cat (Dasyurus hallucatus). Marsupials are of particular interest in developmental studies because much embryonic development occurs outside the uterus, in the pouch. Nissl-stained material was prepared from pouch-young at various ages between 11 and 81 days, and for a number of adults. Four pouch-young were injected with tritiated thymidine and killed later during pouch life. The inferior colliculus is first recognizable in pouch-young aged 23 days, when it is bordered by a cell-sparse ring of tissue. By this time, the labelling patterns following injections of tritiated thymidine made on days 7-9 suggest that migration of cells to the inferior colliculus from the ventricular germinal zone has been largely completed. At 81 days, close to the time when the young move out of the pouch, the adult cytoarchitecture--a central nucleus flanked by dorsal and lateral cortical regions--is clear. Cell areas expand monotonically as a function of age. The period of days 45-50 is associated with a large expansion of cell volume and a concomitant decrease in packing density. It is likely that functional connections are forming during this period, which may herald the onset of hearing in the quoll. Total cell numbers increase to a peak at day 36, fall to a minimum at day 50, and rise again to the adult value. The second increase is likely to be a phase of glial proliferation, in part associated with the onset of myelination. This increase correlates with departure of the young from the pouch.

Aging↗