Early versus delayed stabilization of pediatric femur fractures: analysis of 387 patients

OBJECTIVES

To assess the effect of timing of femur fracture stabilization on pulmonary complication rates in pediatric trauma patients.

DESIGN

Retrospective review.

SETTING

Level I trauma center.

PATIENTS

Three hundred eighty-seven previously healthy patients from zero to fifteen years of age with traumatic diaphyseal femur fractures.

INTERVENTION

Femur fracture stabilization: early (less than twenty-four hours after injury) in 213 patients and late in 174 patients.

MAIN OUTCOME MEASUREMENTS

Age, sex, GCS (Glasgow Coma Score), AIS/ISS (Abbreviated Injury Score/Injury Severity Score), timing of fracture stabilization, duration of mechanical ventilation, intensive care unit stay, and hospital stay were recorded. Pulmonary complications, including pneumonia, respiratory distress syndrome, and pulmonary embolus, were recorded.

RESULTS

Thirteen patients developed pulmonary complications. Twelve of these had severe head injuries (GCS < or = 8). One had sustained an upper cervical spine fracture that resulted in quadriplegia. Statistical analysis revealed GCS, GCS < or = 8, ISS, and head and neck AIS to be significant predictors of pulmonary complications. Early stabilization of femur fractures had no apparent effect on the pulmonary complication rate.

CONCLUSIONS

Pulmonary complications are rare in pediatric femur fracture patients. Patients with severe head injuries (GCS < or = 8) or cervical spinal cord injuries are at high risk for pulmonary complications. The timing of femur fracture stabilization does not appear to affect the prevalence of pulmonary complications in these patients.

The built environment as a component of quality care: understanding and including the patient's perspective

BACKGROUND

Although there has been little systematic assessment of how the built environment of health care facilities affects the quality of care, the built environment is a major element of structure of care--one of three facets of quality. Yet in contrast to the growing trend of using consumer perceptions of both processes and outcomes of care in QI activities, quality assessments of the structure of care do not currently rely on patient feedback. PURPOSE OF PROJECT: During the initial phase of a multiphase project, nine focus groups were conducted in 1997 to identify the salient dimensions of experience from the patient's perspective. The content of these focus groups guided the development of assessment tools in the second phase of the project, which began in February 1998.

FINDINGS

Participants in three focus groups that were held in each of three settings--ambulatory care, acute care, and long term care--described in detail a variety of reactions to the built environment. Analysis revealed eight consistent themes in what patients and family member consumers look for in the built environment of health care. In all three settings, they want an environment, for example, that facilitates a connection to staff and caregivers, is conducive to a sense of well-being, and facilitates a connection to the outside world.

DISCUSSION

Data derived from the focus group research has guided the development of quantitative survey and assessment tools. For each setting, patient-centered checklists and questionnaires are designed to help institutions set priorities for the improvement of facility design from the patient's perspective.

Bloodspot testosterone assay suitable for study of neonates and monitoring of children with congenital adrenal hyperplasia

A bloodspot assay for testosterone has been developed using an antiserum raised against testosterone-3-carboxymethyloxime-bovine serum albumin (T-3 CMO-BSA) conjugate and 125I-T-3CMO-histamine tracer. The method has a detection limit of 0.4 nmol/L with between-batch precision of less than 15% for testosterone values between 0.9 and 2.0 nmol/L and less than 10% for values greater than 2.0 nmol/L. Recovery of 4 nmol/L testosterone spiked into whole blood samples from 16 women (with unspiked bloodspot testosterone concentrations ranging from 0.4 to 3.7 nmol/L) was 100.9%. Bloodspot testosterone concentration was measured in thirty 6-9 day old infants (19 boys, 11 girls) with an absolute range in boys of < 0.4-2.3 nmol/L and in girls of < 0.4 nmol/L. In preterm infants (12 boys, 12 girls) of varying birth gestation and postnatal age, levels were higher than in term infants, with boys showing a rise with increasing postnatal age. Daytime bloodspot profiles in four children on replacement therapy for congenital adrenal hyperplasia demonstrated consistently low testosterone levels in the presence of moderately elevated early morning 17-hydroxyprogesterone concentrations, thus indicating adequate treatment. The bloodspot testosterone assay can be applied to the study of androgen physiology in preterm neonates as well as for monitoring treatment in disorders such as congenital adrenal hyperplasia.

The clinical performance of new degree graduates

Since the transfer of nursing education from hospitals to tertiary institutions, debate regarding the competence of new graduates has continued. To date this issue has not been thoroughly researched. The lack of research related to the competence of degree graduates in New Zealand provided the impetus for this study, which was aimed toward identifying how graduates perceived their clinical performance during their first year of practice. A convenience sample of 30 graduates was surveyed after 3 months and 7 months in practice, using an adapted form of a questionnaire devised by Ryan and Hodson (1992). The results showed that over time, graduates generally required less direction in all areas of clinical competence. After 7 months in practice, the majority of the graduates rated their performance in nursing skills, communication skills, and professionalism at the expected level or above. However, some still required direction with using theory and research in practice, with meeting client's psychosocial needs and with teaching clients. In the leadership competency, after 7 months, most graduates saw themselves functioning at the expected level related to client care and needed less direction in unit management skills. However, many of the unit management skills were rated as 'not applicable' indicating that new graduates are not initially placed in a management role. Implications for nursing education and limitations of the research are discussed.

Cancer mortality in health and science technicians

BACKGROUND

Nearly one million U.S. women are employed as health or science technicians with various chemical and biological exposures, but few studies have looked at their health outcomes.

METHODS

Using 1984-1995 mortality data with coded occupation information, we calculated race- and age-adjusted proportionate cancer mortality ratios (PCMRs) and 95% confidence intervals for two age groups for black and white women with occupations of clinical laboratory (CLT), radiologic, and science technician.

RESULTS

For CLTs, the PCMRs for breast cancer were borderline significantly elevated. The PCMRs for leukemia were significantly elevated, particularly for myeloid leukemia. Radiologic technicians had no significantly elevated PCMRs. Science technicians had significantly elevated PCMRs for non-Hodgkin's lymphoma and multiple myeloma in the younger age group.

DISCUSSION

The elevated risks for lymphatic and hematopoietic neoplasms in CLTs and science technicians may be associated with occupational exposures.

The cost of radiotherapy as a function of facility size and hours of operation

Against a background of constant or decreasing budgets, this study was undertaken to investigate the economic effects of changes in selected operational parameters within a radiation treatment programme. Using financial data from the Northeastern Ontario Regional Cancer Centre and a recognized staffing model, a commercial spreadsheet has been used to calculate the cost of an 18 fraction course of radiotherapy, including all the major preparatory processes such as simulation and treatment planning. Using the spreadsheet, and on the basis of explicit and reasonable assumptions, the cost of radiotherapy has been calculated as the facility size (i.e. equipment complement) and hours of operation are varied. Based on the assumptions used, the cost of radiotherapy in a facility treating less than about 1600 patients per year starts to rise. At 400 patients per year, a course costs approximately 50% more than at 1600 patients per annum. Extended hours of operation do not appear to generate significant, if any, savings when realistic assumptions about machine lifetime and overtime payments are made. Using a spreadsheet to simulate changes in a radiation treatment programme can be an important decision-making tool, as the effects of changes in operating parameters can be demonstrated.

Human health implications of environmental contaminants in Arctic Canada: a review

This paper assesses the impact on human health of exposure to current levels of environmental contaminants in the Canadian Arctic, and identifies the data gaps that need to be filled by future human health research and monitoring. The concept of health in indigenous groups of the Arctic includes social, cultural, and spiritual dimensions. The harvesting, sharing and consumption of traditional foods are an integral component to good health among Aboriginal people influencing both physical health and social well-being. Traditional foods are also an economic necessity in many communities. Consequently, the contamination of country food raises problems which go far beyond the usual confines of public health and cannot be resolved by health advisories or food substitutions alone. The primary exposure pathway for the contaminants considered in this paper is through the traditional northern diet. For the Inuit, the OCs of primary concern at this time from the point of view of exposure are chlordane, toxaphene, and PCBs. Exposures are higher in the eastern than in the western region of the North. For Dene/Metis, exposure to OCs is in general below a level of concern. However, estimated intake of chlordane and toxaphene has been found to be elevated for certain groups and is a cause for concern if exposures are elevated on a regular basis. The developing foetus and breast-fed infant are likely to be more sensitive to the effects of OCs and metals than individual adults and are the age groups at greatest risk in the Arctic. Extensive sampling of human tissues in the Canadian north indicate that a significant proportion of Dene, Cree and Inuit had mean maternal hair mercury levels within the 5% risk-range proposed by the WHO for neonatal neurological damage. Based on current levels, lead does not appear to pose a health threat while cadmium is likely only a major risk factor for heavy smokers or consumers of large amounts of organ meats. Consumers of traditional foods are exposed to an approximately seven-fold higher radiation dose than non-consumers of traditional foods due predominantly to the bioaccumulation of natural radionuclides in the food chain. Risk determination for contaminants in country food involves a consideration of the type and amounts of food consumed and the sociocultural, nutritional, economic, and spiritual benefits associated with country foods. Risk management options that minimize the extent to which nutritional and sociocultural aspects of Aboriginal societies are compromised must always be considered.

Expectations of independence and life satisfaction among ageing spinal cord injured adults

PURPOSE

The present study offers information about independence and life satisfaction over the lifespan for individuals with traumatic spinal cord injuries.

METHODS

The study uses the health expectancy methodology to estimate expectations of the remaining years of life that may be spent in states of independence and satisfaction with life.

SUBJECTS

The cohort studied had all incurred a spinal cord injury between the ages of 25 and 34, between the years 1945 and 1990 in central and south-eastern Ontario.

RESULTS AND CONCLUSIONS

The study found that levels of independence and quality of life in the sample conformed closely to those found in other similar studies with the spinal cord injured population: 22% reported their own functional status as dependent, and 22% reported fair to poor life satisfaction. Expectations of independence appeared to decline steadily over the five decades studied, while expectations of modified independence increased proportionally. Estimates varied significantly for those with paraplegia vs. quadriplegia, and those with complete vs. incomplete lesions. Expectations of life satisfaction appeared to change after the 30 year mark; at that point, the balance changed so that expectations of dissatisfaction outweighed expectations of satisfaction. Multiple regression showed that independence was related to lesion level, completeness and recency of injury, and both independence and satisfaction were related to marriage and employment.

Structural requirements for CD43 function

The regulation of T cell activation and adhesion by CD43 (leukosialin, sialophorin) has been thought to be mainly a function of the large size and negative charge of the extracellular domain of the protein. In this work, we demonstrate that the cytoplasmic tail is both necessary and sufficient for the negative regulatory effect of CD43 on cell-cell adhesion. Expression of mutant CD43 proteins in primary T cells from CD43-deficient mice demonstrated that the antiproliferative effect of CD43 is also dependent upon the cytoplasmic tail. In contrast, Ab-mediated costimulation through CD43 does not require the intracellular domain of CD43. These data demonstrate that CD43 primarily serves as a negative regulator of T cell activation and adhesion, and that this is mediated not exclusively by passive effects of the extracellular domain, but requires participation of the cytoplasmic tail, perhaps through interactions with the cytoskeleton, or alternatively, active regulation of intracellular signaling pathways.

Subsequent obstetric performance related to primary mode of delivery

OBJECTIVE

To relate subsequent obstetric performance with primary mode of delivery.

DESIGN

Postal questionnaire survey of women who delivered their first child five years ago.

SETTING

Huddersfield Royal Infirmary.

POPULATION

Women who were delivered of their first baby in 1991: 250 by normal vaginal delivery; 250 by instrumental vaginal delivery; and 250 by caesarean section.

MAIN OUTCOME MEASURES

Answers to fixed choice questions on fear of future childbirth, number of subsequent children and reasons for no further children.

RESULTS

The response rate was 64%. Overall, 222 (46.6%) women were initially frightened about future childbirth. According to mode of delivery: 93 (57.1%) after instrumental vaginal; 79 (47.9%) after caesarean section; and 50 (33.8%) after normal vaginal delivery. Five years after the primary delivery, 99 women (20.8%) were still frightened about future childbirth: instrumental vaginal group 41 (25.2%); caesarean section group 43 (26.1%); and normal vaginal group 15 (10.1%). In the group of women who were delivered by caesarean section 13% more women had not had a second child after five years compared with the normal vaginal delivery group ((P < 0.03, relative risk 1.46 (1.07-1.99)). In the group of women who had a vaginal instrumental delivery 6% more had not had a second child after five years compared with normal vaginal delivery group. Of the women who had no further children, 30% who had caesarean section and 28% vaginal instrumental delivery had involuntary infertility.

CONCLUSIONS

Caesarean section or vaginal instrumental delivery leaves many mothers frightened about future childbirth. Primary caesarean section and to some extent vaginal instrumental delivery is associated with an increased risk of voluntary and involuntary infertility.

Subtyping of methicillin-resistant Staphylococcus aureus isolates from the North-West of England: a comparison of standardised pulsed-field gel electrophoresis with bacteriophage typing including an inter-laboratory reproducibility study

Bacteriophage typing is currently the recognised methodology for the typing of methicillin-resistant Staphylococcus aureus (MRSA) in the UK. Bacteriophage typing is less discriminatory and does not type all isolates compared with some molecular methods for typing MRSA. Chromosomal genotyping by pulsed-field gel electrophoresis (PFGE) is increasingly recognised as an improved method for typing MRSA, providing increased discrimination and typability. In this study the results of a comparison of bacteriophage typing and PFGE typing and subtyping are presented for a large collection of isolates from the North-West of England. Isolates belonging to the most frequently isolated epidemic methicillin-resistant Staphylococcus aureus (EMRSA) bacteriophage types 15 and 16 were typed by PFGE with further discrimination of common PFGE types possible into a number of subtypes. These results for a large collection of isolates demonstrate the improved typing of MRSA with PFGE. The widespread acceptance of PFGE for typing MRSA isolates has been hampered by the lack of standardised methodologies. Recently, a standardised PFGE strain typing system, known as the GenePath system has become available. The results of an inter-laboratory comparison of PFGE typing for a collection of isolates demonstrated good reproducibility with this system.

Unusual case of tracheal agenesis

We describe the clinical presentation and pathological features of an unusual case of tracheal agenesis. The axial derivatives of the primitive foregut between the larynx and stomach were represented by a single structure featuring sequential segmentation into regions showing exclusively tracheal or esophageal differentiation in a pattern that is not easily classified by existing nosologic systems nor explained by the conventional hypothesis of dysontogenesis.

Cardiovascular response during head-up tilt in chronic fatigue syndrome

This study examined the cardiovascular response to orthostatic challenge, and incidence and mechanisms of neurally mediated hypotension in chronic fatigue syndrome (CFS) during a head-up tilt test. Stoke volume was obtained by a thoracic impedance cardiograph, and continuous heart rate and blood pressure were recorded during a 45-min 70 degrees head-up tilt test. Thirty-nine CFS patients and 31 healthy physically inactive control subjects were studied. A positive tilt, i.e. a drop in systolic blood pressure of > 25 mmHg, no concurrent increase in heart rate and/or development of presyncopal symptoms, was seen in 11 CFS patients and 12 control subjects (P > 0.05). During baseline and the first 5 min of head-up tilt, CFS patients had higher heart rate and smaller pulsatile-systolic area than control subjects (P < 0.05). Among subjects who completed the test, those with CFS had higher heart rate and smaller stroke volume (P < 0.05) than corresponding control subjects. When comparing those who had a positive test outcome in each group, CFS patients had higher heart rates and lower pulse pressure and pulsatile-systolic areas during the last 4 min before being returned to supine (P < 0.05). These data show that there are baseline differences in the cardiovascular profiles of CFS patients when compared with control subjects and that this profile is maintained during head-up tilt. However, the frequency of positive tilts and the haemodynamic adjustments made to this orthostatic challenge are not different between groups.

Obstacles to timely neonatal screening in North Thames

OBJECTIVE

To assess the timeliness of neonatal (Guthrie card) screening in North Thames, and to identify the most effective ways of improving it.

DESIGN

Analysis of information routinely collected in the course of neonatal screening; reanalysis of published data on blood phenylalanine concentration in phenylketonuria (PKU) over the first two weeks; simulation studies on the impact of different interventions.

SUBJECTS

100,690 infants born over one year and screened at Great Ormond Street Hospital NHS Trust.

OUTCOME MEASURE

Interval between birth and reading PKU screen results.

RESULTS

Although 75% of samples (district range 55-91%) were collected by day 7, only 81% had arrived in the laboratory seven days later (range 57-96%). The average interval between birth and reading results was 14.5 days, with only 9.7% read by day 10. Samples could be collected from day 4 without significant impact on false negative rates for PKU. If samples were collected from day 4 and posted promptly (second class), the average interval between birth and reading results could be reduced to 9.3 days. If first class mail were used and the laboratory operated on Saturdays, and used assays that could be read the same day rather than bacterial inhibition assays, the average would be 7.8 days, with 96% read by day 10.

CONCLUSION

Timeliness of neonatal screening shows unacceptable variation between districts, and delays in dispatch of specimens to the laboratory. Same day, first class posting should be introduced, and samples could be collected between days 4 and 8.

Electromagnetic fields influence NGF activity and levels following sciatic nerve transection

Pulsed electromagnetic fields (PEMF) have been shown to increase the rate of nerve regeneration. Transient post-transection loss of target-derived nerve growth factor (NGF) is one mechanism proposed to signal induction of early nerve regenerative events. We tested the hypothesis that PEMF alter levels of NGF activity and protein in injured nerve and/or dorsal root ganglia (DRG) during the first stages of regeneration (6-72 hr). Rats with a transection injury to the midthigh portion of the sciatic nerve on one side were exposed to PEMF or sham control PEMF for 4 hr/day for different time periods. NGF-like activity was determined in DRG, in 5-mm nerve segments proximal and distal to the transection site and in a corresponding 5-mm segment of the contralateral nonoperated nerve. NGF-like activity of coded tissue samples was measured in a blinded fashion using the chick DRG sensory neuron bioassay. Overall, PEMF caused a significant decrease in NGF-like activity in nerve tissue (P < 0.02, repeated measures analysis of variance, ANOVA) with decreases evident in proximal, distal, and contralateral nonoperated nerve. Unexpectedly, transection was also found to cause a significant (P=0.001) 2-fold increase in DRG NGF-like activity between 6 and 24 hr postinjury in contralateral but not ipsilateral DRG. PEMF also reduced NGF-like activity in DRG, although this decrease did not reach statistical significance. Assessment of the same nerve and DRG samples using ELISA and NGF-specific antibodies confirmed an overall significant (P < 0.001) decrease in NGF levels in PEMF-treated nerve tissue, while no decrease was detected in DRG or in nerve samples harvested from PEMF-treated uninjured rats. These findings demonstrate that PEMF can affect growth factor activity and levels, and raise the possibility that PEMF might promote nerve regeneration by amplifying the early postinjury decline in NGF activity.

Dual roles of p82, the clam CPEB homolog, in cytoplasmic polyadenylation and translational masking

In the transcriptionally inert maturing oocyte and early embryo, control of gene expression is largely mediated by regulated changes in translational activity of maternal mRNAs. Some mRNAs are activated in response to poly(A) tail lengthening; in other cases activation results from de-repression of the inactive or masked mRNA. The 3' UTR cis-acting elements that direct these changes are defined, principally in Xenopus and mouse, and the study of their trans-acting binding factors is just beginning to shed light on the mechanism and regulation of cytoplasmic polyadenylation and translational masking. In the marine invertebrate, Spisula solidissima, the timing of activation of three abundant mRNAs (encoding cyclin A and B and the small subunit of ribonucleotide reductase, RR) in fertilized oocytes correlates with their cytoplasmic polyadenylation. However, in vitro, mRNA-specific unmasking occurs in the absence of polyadenylation. In Walker et al. (in this issue) we showed that p82, a protein defined as selectively binding the 3' UTR masking elements, is a homolog of Xenopus CPEB (cytoplasmic polyadenylation element binding protein). In functional studies reported here, the elements that support polyadenylation in clam egg lysates include multiple U-rich CPE-like motifs as well as the nuclear polyadenylation signal AAUAAA. This represents the first detailed analysis of invertebrate cis-acting cytoplasmic polyadenylation signals. Polyadenylation activity correlates with p82 binding in wild-type and CPE-mutant RR 3' UTR RNAs. Moreover, since anti-p82 antibodies specifically neutralize polyadenylation in egg lysates, we conclude that clam p82 is a functional homolog of Xenopus CPEB, and plays a positive role in polyadenylation. Anti-p82 antibodies also result in specific translational activation of masked mRNAs in oocyte lysates, lending support to our original model of clam p82 as a translational repressor. We propose therefore that clam p82/CPEB has dual functions in masking and cytoplasmic polyadenylation.

Improved recognition of MRSA case clusters by the application of molecular subtyping using pulsed-field gel electrophoresis

Methicillin-resistant Staphylococcus aureus (MRSA) is increasingly common in hospital and community populations, making the recognition of true nosocomial outbreaks more difficult. We have used pulsed-field gel electrophoresis (PFGE) with Sma I digestion to analyse retrospectively two perceived outbreaks of epidemic methicillin-resistant Staphylococcus aureus 15 (EMRSA 15) colonization. The first cluster of cases in patients and staff on a general ward (ward D) revealed three different antibiograms based on differences in ciprofloxacin and rifampicin sensitivities. All isolates typed using PFGE, which was more discriminatory than phage-typing. One PFGE banding profile labelled type 5 was predominant, but 12 isolates proved to be subtypes of type 5 and two were PFGE type 11. Four staff members carried a strain not found in patients, three carried strains found in patients and transient carriage was highlighted as a problem when screening staff. PFGE enhanced the epidemiological data and proved that the cases on this ward did not comprise one large outbreak but numerous sporadic cases and smaller clusters. In contrast, isolates from a second cluster of cases which occurred on ward F were indistinguishable using antibiograms, phage-typing and PFGE, confirming this was more likely to be a true outbreak of colonization. We conclude that PFGE usefully augments epidemiological information and allows more logical infection control decisions to be made, with better utilization of scarce resources.

The clam 3' UTR masking element-binding protein p82 is a member of the CPEB family

During early development gene expression is controlled principally at the translational level. Oocytes of the surf clam Spisula solidissima contain large stockpiles of maternal mRNAs that are translationally dormant or masked until meiotic maturation. Activation of the oocyte by fertilization leads to translational activation of the abundant cyclin and ribonucleotide reductase mRNAs at a time when they undergo cytoplasmic polyadenylation. In vitro unmasking assays have defined U-rich regions located approximately centrally in the 3' UTRs of these mRNAs as translational masking elements. A clam oocyte protein of 82 kDa, p82, which selectively binds the masking elements, has been proposed to act as a translational repressor. Importantly, mRNA-specific unmasking in vitro occurs in the absence of poly(A) extension. Here we show that clam p82 is related to Xenopus CPEB, an RNA-binding protein that interacts with the U-rich cytoplasmic polyadenylation elements (CPEs) of maternal mRNAs and promotes their polyadenylation. Cloned clam p82/CPEB shows extensive homology to Xenopus CPEB and related polypeptides from mouse, goldfish, Drosophila and Caenorhabditis elegans, particularly in their RNA-binding C-terminal halves. Two short N-terminal islands of sequence, of unknown function, are common to vertebrate CPEBs and clam p82. p82 undergoes rapid phosphorylation either directly or indirectly by cdc2 kinase after fertilization in meiotically maturing clam oocytes, prior to its degradation during the first cell cleavage. Phosphorylation precedes and, according to inhibitor studies, may be required for translational activation of maternal mRNA. These data suggest that clam p82 may be a functional homolog of Xenopus CPEB.

Epidemiological characterization of methicillin-resistant Staphylococcus aureus isolated in the North West of England by protein A (spa) and coagulase (coa) gene polymorphisms

In a comparative study, isolates of methicillin-resistant Staphylococcus aureus (MRSA) with known pulsed-field gel electrophoresis (PFGE) and bacteriophage type were analysed by polymerase chain reaction (PCR) and restriction fragment length polymorphisms (RFLP) for additional discriminatory subtyping information. PFGE was previously performed using standardized, commercially available kits and pre-programmed software. Isolates were examined for coagulase (coa) and protein A (spa) gene polymorphisms following PCR amplification of the coa hypervariable and spa repeat regions. Coa gene RFLPs produced a total of 38 distinct combined patterns after digestion with HaeIII and AluI and identified the predominant epidemic (EMRSA) types 15 and 16. A unique HaeIII restriction site was identified by RFLP and sequence analysis in the coa gene for EMRSA 15 but not EMRSA 16. The spa gene PCR yielded a total of 14 different profiles ranging from 3-18 repeats with the 2 predominant EMRSA types falling into 2 distinct groups. PCR detection of coa and spa polymorphisms offer a rapid preliminary strain identification and discriminatory subtyping information for surveillance of MRSA.