Biomedical subjects

Allison McGeer

Publications and source records attributed to Allison McGeer.

At least 19 recordsLinked to original sources

PubMed2024

Rapid inference of antibiotic susceptibility phenotype of uropathogens using metagenomic sequencing with neighbor typing.

UNLABELLED: Timely diagnostic tools are needed to improve antibiotic treatment. Pairing metagenomic sequencing with genomic neighbor typing algorithms may support rapid clinically actionable results. We created resistance-associated sequence elements (RASE) databases for Escherichia coli and Klebsiella spp. and used them to predict antibiotic susceptibility in directly sequenced (Oxford Nanopore) urine specimens from critically ill patients. RASE analysis was performed on pathogen-specific reads from metagenomic sequencing. We evaluated the ability to predict (i) multi-locus sequence type (MLST) and (ii) susceptibility profiles. We used neighbor typing to predict MLST and susceptibility phenotype of E. coli (64/80) and Klebsiella spp. (16/80) from urine samples. When optimized by lineage score, MLST predictions were concordant for 73% of samples. Similarly, a RASE-susceptible prediction for a given isolate was associated with a specificity and a positive likelihood ratio (LR+) for susceptibility of 0.65 (95% CI, 0.54-0.76) and 2.26 (95% CI, 1.75-2.92), respectively, with an increase in the probability of susceptibility of 10%. A RASE-non-susceptible prediction was associated with a sensitivity and a negative likelihood ratio (LR-) for susceptibility of 0.79 (95% CI, 0.74-0.84) and 0.32 (95% CI, 0.24-0.43) respectively, with a decrease in the probability of susceptibility of 20%. Numerous antibiotic classes could reasonably be reconsidered empiric therapy by shifting empiric probabilities of susceptibility across relevant treatment thresholds. Moreover, these predictions can be available within 6 h. Metagenomic sequencing of urine specimens with neighbor typing provides rapid and informative predictions of lineage and antibiotic susceptibility with the potential to impact clinical decision-making. IMPORTANCE: Urinary tract infections (UTIs) are a common diagnosis in hospitals and are often treated empirically with broad-spectrum antibiotics. These broad-spectrum agents can select for resistance in these bacteria and co-colonizing organisms. The use of narrow-spectrum agents is desirable as an antibiotic stewardship measure; however, it is counterbalanced by the need for adequate therapy. Identification of causative organisms and their antibiotic susceptibility can help direct treatment; however, conventional testing requires days to produce actionable results. Methods to quickly and accurately predict susceptibility phenotypes for pathogens causing UTI could thus improve both patient outcomes and antibiotic stewardship. Here, expanding on previous work showing accurate prediction for certain Gram-positive pathogens, we demonstrate how the use of RASE from metagenomic sequencing can provide informative and rapid phenotype prediction results for common Gram-negative pathogens in UTI, highlighting the future potential of this method to be used in clinical settings to guide empiric antibiotic selection.

Humans↗

PubMed2007

Effect of multivitamin and mineral supplementation on episodes of infection in nursing home residents: a randomized, placebo-controlled study.

OBJECTIVES: To evaluate the effect of vitamin and mineral supplementation on infections in an elderly institutionalized population. DESIGN: Eighteen-month, randomized, placebo-controlled trial. SETTING: Twenty-one long-term care facilities. PARTICIPANTS: Seven hundred sixty-three subjects from 21 long-term care facilities. INTERVENTION: Participants were randomized to receive one multivitamin and mineral supplementation daily or placebo. MEASUREMENTS: The primary outcome was number of infections per subject. Secondary outcomes were antibiotic use and hospitalization rates. Infection control surveillance was conducted over 18 months using standardized criteria. RESULTS: Outcome data from 748 subjects, mean age 85, were included in the intention-to-treat analysis. Using univariate analyses, there was no difference in infectious episodes between the supplemented and placebo groups (3.5 infections per 1,000 resident-days vs 3.8 infections per 1,000 resident-days, odds ratio (OR)=0.92, 95% confidence interval (CI)=0.82-1.03, P=.12). There was a reduction in antibiotic usage in the supplementation group, but this was not significant in the multivariate model. There was no difference in the number of hospital visits. In the multivariate analysis, the effect of multivitamin use on total number of infections was not significant (OR=0.77, 95% CI=0.54-1.1). Subjects without dementia had a greater rate of infections than those with dementia (OR=1.44, 95% CI=1.19-1.76). In post hoc subgroup analysis, subjects without dementia who received supplementation had a significantly lower rate of infections than those who received placebo (relative risk=0.81, 95% CI=0.66-0.99). CONCLUSION: Overall, multivitamin and mineral supplementation does not have a significant effect on the incidence of infections in institutionalized seniors, although the subgroup of residents in long-term care without dementia may benefit from supplementation. Further research is needed to determine its effect in high-risk subgroups within the nursing home population.

Aged↗

PubMed2006

Randomized controlled trial of chlorhexidine gluconate for washing, intranasal mupirocin, and rifampin and doxycycline versus no treatment for the eradication of methicillin-resistant Staphylococcus aureus colonization.

BACKGROUND: Eradication of methicillin-resistant Staphylococcus aureus (MRSA) carriage may reduce the risk of MRSA infection and prevent transmission of the organism to other patients. METHODS: To determine the efficacy of decolonization therapy, patients colonized with MRSA were randomized (3:1 allocation) to receive treatment (2% chlorhexidine gluconate washes and 2% mupirocin ointment intranasally, with oral rifampin and doxycycline for 7 days), or no treatment. Follow-up samples for MRSA culture were obtained from the nares, perineum, skin lesions, and catheter exit sites monthly for up to 8 months. The primary outcome measure was detection of MRSA at 3 months of follow-up. Univariate and multivariable analyses were performed to identify variables associated with treatment failure. RESULTS: Of 146 patients enrolled in the study, 112 patients (87 treated; 25 not treated) were followed up for at least 3 months. At 3 months of follow-up, 64 (74%) of those treated had culture results negative for MRSA, compared with 8 (32%) of those not treated (P=.0001). This difference remained significant at 8 months of follow-up, at which time, 54% of those treated had culture results negative for MRSA (chi2=64.4; P<.0001, by log-rank test). The results of the multivariable analysis indicated that having a mupirocin-resistant isolate at baseline was associated with treatment failure (relative risk, 9.4; 95% confidence interval, 2.8-31.9; P=.0003), whereas decolonization therapy was protective (relative risk, 0.1; 95% confidence interval, 0.04-0.4; P=.0002). Mupirocin resistance emerged in only 5% of follow-up isolates. CONCLUSIONS: Treatment with topical mupirocin, chlorhexidine gluconate washes, oral rifampin, and doxycycline for 7 days was safe and effective in eradicating MRSA colonization in hospitalized patients for at least 3 months.

Administration, Intranasal↗

PubMed2006

Guillain-Barré syndrome after influenza vaccination in adults: a population-based study.

BACKGROUND: Whether influenza vaccination is associated with Guillain-Barré syndrome (GBS) remains uncertain. METHODS: We conducted 2 studies using population-based health care data from the province of Ontario, Canada. In the first study, we used the self-matched case-series method to explore the temporal association between probable influenza vaccination (adults vaccinated during October and November) and subsequent hospitalization because of GBS. In the second study, we used time-series analysis to determine whether the institution of a universal influenza immunization program in October 2000 was associated with a subsequent increase in hospital admissions because of GBS at the population level. RESULTS: From April 1, 1992, to March 31, 2004, we identified 1601 incident hospital admissions because of GBS in Ontario. In 269 patients, GBS was diagnosed within 43 weeks of vaccination against influenza. The estimated relative incidence of GBS during the primary risk interval (weeks 2 through 7) compared with the control interval (weeks 20 through 43) was 1.45 (95% confidence interval, 1.05-1.99; P = .02). This association persisted in several sensitivity analyses using risk and control intervals of different durations. However, a separate time-series analysis demonstrated no evidence of seasonality and revealed no statistically significant increase in hospital admissions because of GBS after the introduction of the universal influenza immunization program. CONCLUSION: Influenza vaccination is associated with a small but significantly increased risk for hospitalization because of GBS.

Adult↗

PubMed2006

Cluster of cases of severe acute respiratory syndrome among Toronto healthcare workers after implementation of infection control precautions: a case series.

OBJECTIVE: To review the severe acute respiratory syndrome (SARS) infection control practices, the types of exposure to patients with SARS, and the activities associated with treatment of such patients among healthcare workers (HCWs) who developed SARS in Toronto, Canada, after SARS-specific infection control precautions had been implemented. METHODS: A retrospective review of work logs and patient assignments, detailed review of medical records of patients with SARS, and comprehensive telephone-based interviews of HCWs who met the case definition for SARS after implementation of infection control precautions. RESULTS: Seventeen HCWs from 6 hospitals developed disease that met the case definition for SARS after implementation of infection control precautions. These HCWs had a mean age (+/-SD) of 39+/-2.3 years. Two HCWs were not interviewed because of illness. Of the remaining 15, only 9 (60%) reported that they had received formal infection control training. Thirteen HCWs (87%) were unsure of proper order in which personal protective equipment should be donned and doffed. Six HCWs (40%) reused items (eg, stethoscopes, goggles, and cleaning equipment) elsewhere on the ward after initial use in a room in which a patient with SARS was staying. Use of masks, gowns, gloves, and eyewear was inconsistent among HCWs. Eight (54%) reported that they were aware of a breach in infection control precautions. HCWs reported fatigue due to an increased number and length of shifts; participants worked a median of 10 shifts during the 10 days before onset of symptoms. Seven HCWs were involved in the intubation of a patient with SARS. One HCW died, and the remaining 16 recovered. CONCLUSION: Multiple factors were likely responsible for SARS in these HCWs, including the performance of high-risk patient care procedures, inconsistent use of personal protective equipment, fatigue, and lack of adequate infection control training.

Adult↗

PubMed2006

Methicillin-resistant Staphylococcus aureus in Canadian aboriginal people.

We describe 279 hospitalized Canadian aboriginals in whom methicillin-resistant Staphylococcus aureus (MRSA) was detected. They were identified in 38 Canadian hospitals from 1995 through 2002. Compared with nonaboriginals, aboriginals were more likely to be younger than 18 years of age (OR, 1.8; P<.0001), to have had an MRSA infection (OR, 3.8; P<.0001), and to have had MRSA isolated from specimens of skin or soft tissue (OR, 4.1; P=.016). The clinical features of MRSA infection in aboriginals are distinct from those in the general patient population with MRSA infection in Canadian hospitals, and the genetic background of MRSA isolates from aboriginals also varies from that of strains from the non-aboriginal population.

Adolescent↗

PubMed2006

Febrile respiratory illness in the intensive care unit setting: an infection control perspective.

PURPOSE OF REVIEW: We have examined studies published since the severe acute respiratory syndrome outbreak that elucidate the mode of transmission of respiratory pathogens and the optimal means of interrupting their transmission, focusing on transmission in the intensive care unit. RECENT FINDINGS: The severe acute respiratory syndrome may be transmitted by the droplet, contact and occasionally the airborne route. Transmission occurred most frequently when healthcare workers failed to use standard precautions such as hand washing or personal protective equipment designed to limit droplet and contact transmission. Aerosol-generating procedures increased transmission, but incomplete use of personal protective equipment during procedures was common. Recent publications have stressed the benefits of appropriate staffing levels, the use of single occupancy rooms, the immunization of healthcare workers against influenza, and the importance of healthcare workers remaining home when ill in reducing the morbidity and mortality of respiratory infection within the intensive care unit. SUMMARY: Most respiratory pathogens can be transmitted by more than one route. Despite this, healthcare worker awareness of clinical syndromes associated with respiratory pathogens that require airborne precautions, combined with the use of standard precautions for all patients, and contact/droplet precautions for patients with undifferentiated febrile respiratory illness should be effective in interrupting the transmission of respiratory pathogens within the intensive care unit.

Air Microbiology↗

PubMed2006

Viable group A streptococci in macrophages during acute soft tissue infection.

BACKGROUND: Group A streptococcal severe soft tissue infections, such as necrotizing fasciitis, are rapidly progressive infections associated with high mortality. Group A streptococcus is typically considered an extracellular pathogen, but has been shown to reside intracellularly in host cells. METHODS AND FINDINGS: We characterized in vivo interactions between group A streptococci (GAS) and cells involved in innate immune responses, using human biopsies (n = 70) collected from 17 patients with soft tissue infections. Immunostaining and in situ image analysis revealed high amounts of bacteria in the biopsies, even in those collected after prolonged antibiotic therapy. Viability of the streptococci was assessed by use of a bacterial viability stain, which demonstrated viable bacteria in 74% of the biopsies. GAS were present both extracellularly and intracellularly within phagocytic cells, primarily within macrophages. Intracellular GAS were predominantly noted in biopsies from newly involved tissue characterized by lower inflammation and bacterial load, whereas purely extracellular GAS or a combination of intra- and extracellular GAS dominated in severely inflamed tissue. The latter tissue was also associated with a significantly increased amount of the cysteine protease streptococcal pyrogenic exotoxin SpeB. In vitro studies confirmed that macrophages serve as reservoirs for viable GAS, and infection with a speB-deletion mutant produced significantly lower frequencies of cells with viable GAS following infection as compared to the wild-type bacteria. CONCLUSIONS: This is the first study to demonstrate that GAS survive intracellularly in macrophages during acute invasive infections. This intracellular presence may have evolved as a mechanism to avoid antibiotic eradication, which may explain our finding that high bacterial load is present even in tissue collected after prolonged intravenous antibiotic therapy. This new insight into the pathogenesis of streptococcal soft tissue infections highlights a need for alternative therapeutic strategies.

Bacterial Proteins↗

PubMed2006

Morbidity and mortality of patients with invasive group A streptococcal infections admitted to the ICU.

STUDY OBJECTIVES: To describe the clinical features and outcome of patients with invasive group A streptococcal (GAS) infections admitted to the ICU. DESIGN: Prospective, population-based surveillance for invasive GAS infections was conducted in Ontario from January 1992 until June 2002. All 62 patients meeting clinical and/or histopathologic criteria for invasive GAS who were admitted to the ICUs of four university-affiliated hospitals in Toronto, Canada were included. Demographic and clinical information were obtained retrospectively by chart review. ICU morbidity data included the occurrence of organ dysfunction (renal, hepatic, coagulation, ARDS), treatment, and interventions such as hemodialysis and mechanical ventilation. MEASUREMENTS AND RESULTS: ARDS developed in 34%, renal dysfunction developed in 55%, hepatic dysfunction developed in 64%, and coagulopathy developed in 69% of patients. A total of 56% of patients were treated with IV polyspecific IgG (IVIG), 81% were intubated and placed on mechanical ventilation, and 21% required renal replacement therapy. The median durations of ICU and hospital stay were 5.3 days and 15.0 days, respectively. The overall mortality was 40%. Mortality correlated directly with acute physiology and chronic health evaluation II score and the number of dysfunctional organs. Survivors were younger, had lower severity of illness scores, fewer dysfunctional organs, and were less likely to have shock or to receive treatment with vasopressors, mechanical ventilation, or pulmonary artery catheters. There was no association between the use of IVIG, surgical intervention, or clindamycin, and survival. Variables independently associated with mortality on multivariable analysis were the presence of coagulopathy (p = 0.0005) and liver dysfunction (p = 0.0123). CONCLUSIONS: Patients with invasive GAS infection admitted to the ICU have a high mortality rate. In this group of patients, coagulopathy and liver failure were independently associated with mortality. We did not observe any association between the use of IVIG, surgical intervention, or clindamycin, and survival.

APACHE↗

PubMed2006

Coordinated response to SARS, Vancouver, Canada.

Two Canadian urban areas received travelers with severe acute respiratory syndrome (SARS) before the World Health Organization issued its alert. By July 2003, Vancouver had identified 5 cases (4 imported); Toronto reported 247 cases (3 imported) and 43 deaths. Baseline preparedness for pandemic threats may account for the absence of sustained transmission and fewer cases of SARS in Vancouver.

Adult↗

PubMed2005

Effect of a multifaceted intervention on number of antimicrobial prescriptions for suspected urinary tract infections in residents of nursing homes: cluster randomised controlled trial.

OBJECTIVE: To assess whether a multifaceted intervention can reduce the number of prescriptions for antimicrobials for suspected urinary tract infections in residents of nursing homes. DESIGN: Cluster randomised controlled trial. SETTING: 24 nursing homes in Ontario, Canada, and Idaho, United States. PARTICIPANTS: 12 nursing homes allocated to a multifaceted intervention and 12 allocated to usual care. Outcomes were measured in 4217 residents. INTERVENTIONS: Diagnostic and treatment algorithm for urinary tract infections implemented at the nursing home level using a multifaceted approach--small group interactive sessions for nurses, videotapes, written material, outreach visits, and one on one interviews with physicians. MAIN OUTCOME MEASURES: Number of antimicrobials prescribed for suspected urinary tract infections, total use of antimicrobials, admissions to hospital, and deaths. RESULTS: Fewer courses of antimicrobials for suspected urinary tract infections per 1000 resident days were prescribed in the intervention nursing homes than in the usual care homes (1.17 v 1.59 courses; weighted mean difference -0.49, 95% confidence intervals -0.93 to -0.06). Antimicrobials for suspected urinary tract infection represented 28.4% of all courses of drugs prescribed in the intervention nursing homes compared with 38.6% prescribed in the usual care homes (weighted mean difference -9.6%, -16.9% to -2.4%). The difference in total antimicrobial use per 1000 resident days between intervention and usual care groups was not significantly different (3.52 v 3.93; weighted mean difference -0.37, -1.17 to 0.44). No significant difference was found in admissions to hospital or mortality between the study arms. CONCLUSION: A multifaceted intervention using algorithms can reduce the number of antimicrobial prescriptions for suspected urinary tract infections in residents of nursing homes.

Aged↗

PubMed2005

Predicting antimicrobial resistance in invasive pneumococcal infections.

BACKGROUND: The prevalence of multiantimicrobial resistance among Streptococcus pneumoniae continues to increase worldwide. In patients presenting with infection possibly due to pneumococci, recognition of risk factors that would identify those likely to have an antibiotic-resistant isolate might assist clinicians in choosing the most appropriate empirical therapy. METHODS: A prospective cohort study of invasive pneumococcal infection was conducted in Toronto, Canada. Risk factors for antimicrobial resistance were evaluated by means of univariate and multivariate modeling. RESULTS: A total of 3339 patients with invasive pneumococcal infection were identified between 1995 and 2002. Multivariate modeling revealed that risk factors for infection with penicillin-resistant as opposed to penicillin-susceptible pneumococci were year of infection (odds ratio [OR], 1.28; P < .001), absence of chronic organ system disease (OR, 1.72; P = .03), and previous use of penicillin (OR, 2.47; P = .006), trimethoprim-sulfamethoxazole (TMP-SMX; OR, 5.97; P < .001), and azithromycin (OR, 2.78; P = .05). Infection with TMP-SMX-resistant pneumococci was associated with absence of chronic organ system disease (OR, 1.64; P = .001) and with previous use of penicillin (OR, 1.71; P = .03), TMP-SMX (OR, 4.73; P < .001), and azithromycin (OR, 3.49; P = .001). Infection with macrolide-resistant isolates was associated with previous use of penicillin (OR, 1.77; P = .03), TMP-SMX (OR, 2.07; P = .04), clarithromycin (OR, 3.93; P < .001), and azithromycin (OR, 9.93; P < .001). Infection with fluoroquinolone-resistant pneumococci was associated with previous use of fluoroquinolones (OR, 12.1; P < .001), current residence in a nursing home (OR, 12.9; P < .001), and nosocomial acquisition of pneumococcal infection (OR, 9.94; P = .003). CONCLUSIONS: Knowledge of antimicrobial use during the 3 months before infection is crucial for determining appropriate therapy for a patient presenting to the hospital with an illness for which S. pneumoniae is a possible cause. Nosocomial acquisition and nursing home acquisition are significant risk factors for infection with fluoroquinolone-resistant pneumococci.

Adolescent↗

PubMed2005

Does isolation prevent the spread of methicillin-resistant Staphylococcus aureus?

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Comment↗

PubMed2005

Detection of airborne severe acute respiratory syndrome (SARS) coronavirus and environmental contamination in SARS outbreak units.

Severe acute respiratory syndrome (SARS) is characterized by a risk of nosocomial transmission; however, the risk of airborne transmission of SARS is unknown. During the Toronto outbreaks of SARS, we investigated environmental contamination in SARS units, by employing novel air sampling and conventional surface swabbing. Two polymerase chain reaction (PCR)-positive air samples were obtained from a room occupied by a patient with SARS, indicating the presence of the virus in the air of the room. In addition, several PCR-positive swab samples were recovered from frequently touched surfaces in rooms occupied by patients with SARS (a bed table and a television remote control) and in a nurses' station used by staff (a medication refrigerator door). These data provide the first experimental confirmation of viral aerosol generation by a patient with SARS, indicating the possibility of airborne droplet transmission, which emphasizes the need for adequate respiratory protection, as well as for strict surface hygiene practices.

Air Microbiology↗

PubMed2005

Can routine laboratory tests discriminate between severe acute respiratory syndrome and other causes of community-acquired pneumonia?

BACKGROUND: The clinical presentation of severe acute respiratory syndrome (SARS) resembles that of other etiologies of community-acquired pneumonia, making diagnosis difficult. Hematological and biochemical abnormalities, particularly lymphopenia, are common in patients with SARS. METHODS: With the use of 2 databases, we compared the ability of the absolute lymphocyte count, absolute neutrophil count, lactate dehydrogenase level, creatine kinase level, alanine aminotransferase level, and serum calcium level at hospital admission to discriminate between cases of SARS and cases of community-acquired pneumonia. The SARS database contained data for 144 patients with SARS from the 2003 Toronto SARS outbreak. The community-acquired pneumonia database contained data for 8044 patients with community-acquired pneumonia from Edmonton, Canada. Patients from the SARS database were matched to patients from the community-acquired pneumonia database according to age, and receiver operating characteristic curves were constructed for each laboratory variable. RESULTS: The areas under the receiver operating characteristic curves (AUCs) demonstrated fair to poor discriminatory ability for all laboratory variables tested except absolute neutrophil count, which had an AUC of 0.80, indicating good discriminatory ability (although there was no cutoff value of the absolute neutrophil count at which reasonable sensitivity or specificity could be obtained). Combinations of any 2 tests did not perform significantly better than did the absolute neutrophil count alone. CONCLUSIONS: Routine laboratory tests, including determination of absolute lymphocyte count, should not be used in the diagnosis of SARS or incorporated into current case definitions of SARS. The role of the absolute neutrophil count in SARS diagnosis is likely limited, but it should be assessed further.

Alanine Transaminase↗

PubMed2005

Beliefs and practices of Ontario midwives about influenza immunization.

With an increasing number of births in Ontario being conducted by midwives, we undertook a survey of the beliefs and practices of 256 licensed Ontario midwives and student midwives about immunization, particularly against influenza. Overall, 42.9% (48/112) of midwives considered that they knew a lot about immunization; however, 36.2% (38/105) reported no education about immunization during their training. A small majority (55.9%) were in favour of vaccination in general and only 2 of 113 reported spending more than 1h discussing vaccination with their clients. Only 26.9% reported having received influenza vaccine in the previous season (compared to 60% of all health care workers in Ontario). Overall, only 37% believed that influenza vaccine is effective, and 22% believed that the vaccine was a greater risk than influenza. Graduation in 1998 or prior was associated with belief in the effectiveness in vaccine, having been vaccinated, and recommending vaccine to clients. Midwives who reported being immunized themselves were more likely to believe in the safety and efficacy of influenza vaccine, and to recommend vaccination to their clients (26% versus 3%, p=0.001). If greater attention is not focused on promoting the utility of immunization to midwives, the success of population immunization programs may be compromised.

Confidence Intervals↗

PubMed2005

Clinical and epidemiologic features of methicillin-resistant Staphylococcus aureus in elderly hospitalized patients.

We describe characteristics of elderly patients with MRSA identified in 37 Canadian hospitals between 1995 and 2002. Of these inpatients, 6,613 (66%) were older than 65 years. They were more likely than younger patients to have been colonized without infection and to have had MRSA isolated from urine or the perineum. The epidemiology and clinical features of these patients is distinct from that of younger patients.

Adult↗

PubMed2005

Modeling transmission of methicillin-resistant Staphylococcus aureus among patients admitted to a hospital.

OBJECTIVE: To determine the impact of the screening test, nursing workload, handwashing rates, and dependence of handwashing on risk level of patient visit on methicillin-resistant Staphylococcus aureus (MRSA) transmission among hospitalized patients. SETTING: General medical ward. METHODS: Monte Carlo simulation was used to model MRSA transmission (median rate per 1,000 patient-days). Visits by healthcare workers (HCWs) to patients were simulated, and MRSA was assumed to be transmitted among patients via HCWs. RESULTS: The transmission rate was reduced from 0.89 to 0.56 by the combination of increasing the sensitivity of the screening test from 80% to 99% and being able to report results in 1 day instead of 4 days. Reducing the patient-to-nurse ratio from 4.3 in the day and 6.8 at night to 3.8 and 5.7, respectively, reduced the number of nosocomial infections from 0.89 to 0.85; reducing the ratio to 1 and 1, respectively, further reduced the number of nosocomial infections to 0.32. Increases in handwashing rates by 0%, 10%, and 20% for high-risk visits yielded reductions in nosocomial infections similar to those yielded by increases in handwashing rates for all visits (0.89, 0.36, and 0.24, respectively). Screening all patients for MRSA at admission reduced the transmission rate to 0.81 per 1,000 patient-days from 1.37 if no patients were screened. CONCLUSION: Within the ranges of parameters studied, the most effective strategies for reducing the rate of MRSA transmission were increasing the handwashing rates for visits involving contact with skin or bodily fluid and screening patients for MRSA at admission.

Cost-Benefit Analysis↗