Clinical and economic effects of mupirocin calcium on preventing Staphylococcus aureus infection in hemodialysis patients: a decision analysis

This study was performed to determine the clinical and economic consequences of alternative strategies of preventing Staphylococcus aureus infection in chronic hemodialysis patients by use of intranasal mupirocin calcium to clear nasal carriage of S aureus. Decision analysis evaluated clinical outcomes and cost-effectiveness of three likely management strategies to address S aureus nasal carriage and prevent subsequent infection in chronic ambulatory hemodialysis patients: (1) screen for S aureus nasal carriage every 3 months and treat those with a positive test result with mupirocin calcium; (2) treat all patients weekly with mupirocin calcium; or (3) no prevention strategy, treat infection only. Rates of nasal carriage of S aureus, S aureus infection rates, proportion of infections attributable to nasal carriage, efficacy of mupirocin, natural history of infection, and patient management strategies were derived from the published literature and supplemented by a panel of experts. Actual payments for medical services were obtained from Medicare parts A and B. Incremental cost-effectiveness was calculated from the perspective of Medicare and subjected to sensitivity analyses. Assuming that 75% of S aureus infections are attributable to nasal carriage in hemodialysis patients, eliminating nasal carriage of S aureus with mupirocin calcium (with or without screening) markedly reduces the number of infections (45% to 55%) and also reduces health care expenditures relative to treating infections when they occur. Annual savings to Medicare are $784,000 to $1,117,000 per 1,000 hemodialysis patients, depending on the prevention strategy. Preventing S aureus infection by eradicating nasal carriage in chronic hemodialysis patients reduces morbidity while simultaneously reducing medical care costs. The decision to eliminate nasal carriage on a regular basis or use a screening test to guide antibiotic therapy is dependent on the tradeoff between improved short-term clinical and cost benefits and the potential for bacterial resistance that may arise from widespread use of mupirocin calcium.

Control of methicillin-resistant Staphylococcus aureus at a university hospital: one decade later

OBJECTIVE

To investigate the cause of increasing rates of nosocomial methicillin-resistant Staphylococcus aureus (MRSA) infection at a university hospital.

DESIGN

Review of data collected by prospective hospital wide surveillance regarding rates of nosocomial MRSA colonization and infection.

SETTING

A 700-bed university hospital providing primary and tertiary care.

PATIENTS

Patients admitted to the hospital between 1986 and 1993 who were found to be infected or colonized with MRSA.

MAIN OUTCOME MEASUREMENT

Rates of MRSA infection and colonization.

RESULTS

MRSA infection or colonization was identified in 399 patients (0.18%) admitted during the 8-year study. There was no correlation between the annual rates of MRSA and methicillin-sensitive Staphylococcus aureus (MSSA) infections (P = .66). The frequency of both nosocomial and non-nosocomial cases increased significantly over the last 4 years of the study (P < .001 for trend). The ratio of patients who had acquired MRSA nosocomially to those admitted who already were infected or colonized decreased significantly during the study period (P = .002 for trend). There was a significant increase in the frequency of patients with MRSA being transferred from nursing homes and other chronic care facilities (P = .011). A cost-benefit analysis suggested that surveillance cultures of patients transferred from other healthcare facilities would save between $20,062 and $462,067 and prevent from 8 to 41 nosocomial infections.

CONCLUSIONS

An increase in the incidence of nosocomial MRSA infection was associated with an increased frequency of transfer of colonized patients from nursing homes and other hospitals. The lack of correlation between rates of MRSA and MSSA infections suggested that MRSA infections significantly increased the overall rate of staphylococcal infection. Screening cultures of transfer patients from facilities with a high prevalence of MRSA may offer significant benefit by preventing nosocomial infections and reducing patient days spent in isolation.

An outbreak of methicillin-resistant Staphylococcus aureus (M.R.S.A.) in a burn unit

An outbreak of methicillin-resistant Staphyllococcus aureus (MRSA) in the burn unit of Siriraj Hospital from August 1990 to July 1991 was reported. Temporary decrease in the incidence of MRSA was observed during a period when no new cases were admitted. The incidence rose again after normal service resumed. Surveillance cultures in 29 patients from May to July 1991 grew MRSA in 19 patients (65.5 per cent). Infection by MRSA was found in 14 patients (48.3 per cent). Methicillin-resistant Staphylococcus aureus first appeared in these patients mainly during the first and second weeks of admission. Wound infections were the only manifestation in 14 patients. Four of the MRSA infected patients died of infection by organisms other than MRSA. Nasal carriage was found in 2 of 25 ward staff members. The cost of treatment for each episode of MRSA infection was as high as 19,322.90 baht. The epidemic of MRSA infections persisted despite all control measures resulting in temporary closure of the ward.

Infection in immunocompromised patients with malignant blood disorders in a district general hospital

The pattern and management of infection in immunocompromised patients over a period of 3 years in a district general hospital has been studied. A total of 222 positive cultures was obtained in 607 episodes of suspected infection all involving patients with malignant blood disorders. Febrile episodes requiring intravenous antibiotics occurred in 248 instances involving 107 patients. The pattern of organisms cultured and the responses to various antibiotic regimes are reported. The costs of antibiotic therapy are considered in the light of the overall response. Of the patients studied, 54 died, infection having a likely causative or contributory part in 21 of them (less than 10% of infective episodes). We conclude that the infective complications of these disorders, particularly in older patients, can be efficiently managed in a district general hospital when full supportive facilities are available.

The continuing problem of 'hospital staphylococci': why?

Nosocomial infections due to staphylococci continue to pose a serious health concern worldwide. Methicillin-resistant Staphylococcus aureus (MRSA) is an important and growing cause of staphylococcal infection. The incidence of MRSA varies throughout the world, but is particularly high in Japan where the incidence is four-times that seen in Europe. The emergence of coagulase-negative staphylococci (CNS) has increased as a significant pathogen in infections associated with prosthetic implants. Evidence suggests that hand carriage by hospital staff is one way in which CNS are introduced onto catheters, intravenous lines and other implant devices. Control measures in the UK have concentrated on the reservoirs of infection, with the aim of preventing infection and the resulting morbidity, mortality and economic burden. At the North Middlesex Hospital, London, UK, an aggressive prophylactic policy for MRSA has been employed since 1987. Data show that it is six times cheaper to treat a carrier than it is to treat an infected patient. Prophylaxis therefore provides a more cost-effective way of controlling the spread of MRSA infection. Such stringent control strategies, coupled with increased awareness and adequate funding, are necessary if the spread of resistant bacteria is to be limited.

Prosthetic osteomyelitis with special reference to the knee: risks, treatment and costs

The overall incidence of osteomyelitis following primary knee arthroplasty is 1-2%. Major risk factors are large prostheses, rheumatoid arthritis, postoperative wound-healing complications, skin infections, and prior deep infections. The major infecting organism is Staphylococcus aureus. Healing of the infection is to be expected in 20% when systemic antibiotics alone are used, in 24% when soft tissue surgery is used, in 50% when resection arthroplasty is used, in 76% when revision arthroplasty is used, in 90% when arthrodesis is used, and in 100% when amputation is used. The direct medical costs average US$ 62,100 for an infected patient and US$ 8600 for a non-infected patient. Attention should focus on prophylactic measures directed towards the soft tissue problems: by avoiding conflicting skin incisions, by gentle handling of the periarticular soft tissues, by avoiding the use of constrained prostheses and oversized compartmental prostheses, by letting wound healing take priority over motion in knees with compromised soft tissues, and by using prophylactic antibiotic treatment for skin ulcers until these have healed.

Cost effectiveness of teicoplanin and ceftriaxone: a once-daily antibiotic regimen

There is a high incidence of staphylococcal infection in febrile neutropenic children with a central venous line. These patients are usually initially treated with empiric antimicrobial therapy that provides broad spectrum coverage. In a study evaluating a conventional regimen of vancomycin 40 mg/kg/d plus ceftazidime 100 mg/kg/d given in three divided doses to 41 febrile children with leukemia or lymphoma, the response rate was 87% after a mean treatment duration of 16 days. A once-daily regimen of an investigational antibiotic, teicoplanin, 10 mg/kg/d and ceftriaxone 50 mg/kg/d evaluated in 47 febrile children with leukemia was found to produce an equivalent rate of success and require the same mean duration of therapy. A cost-effectiveness analysis comparing the economic impact of replacing the conventional regimen with once-daily teicoplanin-ceftriaxone revealed that a 16-day course of the latter treatment would produce cost savings in terms of the cost of the antibiotics and other nonreusable materials, as well as in nursing time. Using French drug pricing data, the savings calculated for drugs and materials were 478 FF ($80 US). The teicoplanin-ceftriaxone regimen saved approximately 14 hours in nursing time per patient. Extrapolations based on estimates of hospital occupancy and the ratio of days a patient receives antibiotic therapy to the total duration of hospital stay suggest that an average hospital ward could achieve monthly costsavings of 7,641 FF ($1,273 US) for antibiotics and materials.

The economic implications of bioengineered mastitis control

This paper estimates the cost of mastitis for the New York dairy sector. The average cost is found to be $125 per cow from reduced milk production, treatment, and increased culling. At the 1988 cow inventory, this translates to approximately $100 million annually for the entire dairy farm sector. When quality and production losses for the processing sector are added, the cost to the New York industry alone is nearly $150 million annually. Two promising new treatments, a bacteriocin and a vaccine, are evaluated. Both have shown effectiveness in preliminary trials against Staphylococcus aureus. Assuming that further development will allow the treatments to be effective against the major bacterial sources of mastitis infections, the treatments are projected to increase the annual income of the New York dairy industry by $18.8 to $39.7 million. The bacteriocin could replace antibiotic usage, a desirable goal in the opinion of many, and the vaccine promises to immunize cows against mastitis very effectively.

A combative healer with no ill-effect. Iodosorb in the treatment of infected wounds

Infected wounds require an antiseptic agent which does not inhibit the healing process. In this trial, Iodosorb ointment and powder succeeded in combining these two qualities.

A seven-year experience with methicillin-resistant Staphylococcus aureus

From July 1983 through June 1990, 319 patients with methicillin-resistant Staphylococcus aureus (MRSA) were identified at the University of California, Davis Medical Center. Initially, our goal was eradication of MRSA from the hospital flora. Our approach was: (a) immediate notification of all MRSA isolates by the microbiology laboratory; (b) strict isolation; (c) cohorting; (d) bathing patients with an iodophor; (e) surveillance cultures of patients and staff; (f) treatment of all colonized persons; and (g) strict isolation on readmission. Control of spread was achieved but eradication was not. In 1987 our strategy was modified in order to establish the least restrictive methods to maintain control of the spread of MRSA. After notification by the microbiology laboratory, we now require: (a) contact isolation; (b) surveillance cultures of patients associated with each new case; and (c) contact isolation for all MRSA patients on readmission. Strict isolation and employee culturing are used only during major outbreaks. We have averaged four new cases of MRSA per month over the 7-year period, including four major outbreaks. Since 1987, we have averaged only three new cases per month with one major MRSA outbreak. Annual cost savings of greater than $50,000 have been realized through the policy modifications. We conclude that the use of contact isolation with some modifications has saved time and money and has successfully controlled the spread of MRSA in our university hospital.

Use of partial budgeting to determine the economic outcome of Staphylococcus aureus intramammary infection reduction strategies in three Ohio dairy herds

Efforts to reduce the prevalence of Staphylococcus aureus intramammary infection were monitored in 3 Ohio dairy herds. Bacteriologic culturing of milk from all lactating cows in each herd was completed multiple times to identify infected cows and monitor reduction. Partial budgeting techniques were used to determine the economic outcome of the reduction program. Of particular emphasis was the economic impact of culling to maintain or achieve milk quality premium payments on the basis of bulk tank somatic cell counts. The prevalence of S aureusinfected cows was reduced in each herd. Culturing of milk from all lactating cows appeared to be an effective method to identify infected cows. Although numbers were limited, it also appeared that culturing of composite quarter samples was effective as a herd screening test to identify S aureus-infected cows. Bacteriologic culturing had a negative financial impact in all 3 herds. Using partial budgeting to assess the economic impact of the programs, it was determined that 2 herds experienced negative financial impacts as a result of an excess culling rate when compared with a 12-month baseline period prior to the initiation of the project. All herds had increased milk production per cow during the study as measured by the mature-equivalent method. However, when actual production was considered, increased milk production in each herd was not as great as that of other Ohio herds enrolled on Dairy Herd Improvement Association testing programs.(ABSTRACT TRUNCATED AT 250 WORDS)

The use of nasal mupirocin ointment to prevent Staphylococcus aureus bacteraemias in haemodialysis patients: an analysis of cost-effectiveness

Nasal carriage of Staphylococcus aureus is a risk factor for the development of infections caused by S. aureus in haemodialysis patients. This study compared the incidence of bacteraemia caused by S. aureus during 6 months of use of nasal 2% calcium mupirocin ('Nasal Bactroban') 3-times a week for nasal carriers with the incidence observed previously in the same dialysis unit without the use of mupirocin. Nasal mupirocin led to the total eradication of nasal carriage of S. aureus, a 4.26-fold reduction in the incidence of S. aureus bacteraemia, and a substantial cost saving. After a cumulative experience of nasal mupirocin in haemodialysis patients of more than 43 patient-years, the development of mupirocin resistance was not observed.

Potential inroads to reducing hospital-acquired staphylococcal infection and its cost

Staphylococci are still the most common agents implicated in hospital-acquired infections. In addition to Staphylococcus aureus, coagulase-negative staphylococci have attracted widespread interest, since they have emerged as the most frequent pathogen in foreign-body related infections. The emergence of methicillin-resistant S. aureus has resulted in increasing use of potentially toxic and extremely expensive antibiotics. To prevent hospital-acquired staphylococcal infections only control measures proven to be effective should be implemented and the cost of infection control procedures should always be considered. Handwashing as the simplest, cheapest, and still the most effective measure should constantly be stressed. In this article, effective procedures for the prevention of hospital-acquired staphylococcal infections are summarized, with special emphasis on cost-saving measures.

Temporal patterns of lost milk production following clinical mastitis in a large Michigan Holstein herd

Cows with three hundred and sixteen cases of clinical mastitis were sampled by microbiologic culture during a 6-mo period on a 1700-cow Michigan Holstein dairy farm. Daily milk weights were obtained on all cows before clinical onset and for 60 d after onset. Predicted post-mastitis production, projected on the basis of premastitis production and the lactation curves of contemporary non-mastitic herdmates, was compared with actual daily milk production during the 60 d following clinical onset. Cows experiencing clinical mastitis produced approximately 341 kg less salable milk during the 60 d after clinical onset compared with projected production. This milk loss included both decreased production and milk withheld from market following antibiotic treatment. Pluriparous cows lost 2.06 times as much milk as first lactation cows, and cows with mastitis occurring before 150 d in lactation lost 1.40 times as much milk when compared with other cows. Cows with mastitis occurring in the winter showed a milk loss 1.37 times greater than cows with mastitis in summer. The identity of the mastitis agent isolated from the clinical case was not strongly associated with the drop in milk production in the 60 d following clinical onset.

Cost of nosocomial infection: relative contributions of laboratory, antibiotic, and per diem costs in serious Staphylococcus aureus infections

This study reports an analysis of the relative importance of laboratory antibiotic, and per diem costs of caring for 58 patients with serious Staphylococcus aureus nosocomial infections. Laboratory costs accounted for 2%, antibiotics for 21%, and per diem costs for 77% of total infection-related costs. Only 45% of patients were hospitalized for additional days specifically because of infection, but these patients stayed an average of 18 extra days. Nosocomial infections with S. aureus resistant to penicillinase-resistant penicillins (PRP) were more frequently associated with additional infection-related days of hospitalization than were PRP-susceptible infections. The cost of PRP-resistant infections was also significantly greater than PRP-susceptible infections, primarily because of the costs of additional days of hospitalization. Rational strategies to control costs of nosocomial infection should focus on two approaches: (1) prevention and (2) reduction of acute hospital days attributable to infections.

Cost-effective eradication of an outbreak of methicillin-resistant Staphylococcus aureus in a community teaching hospital

During an eight-month period, 25 hospitalized patients became infected or colonized with methicillin-resistant Staphylococcus aureus (MRSA) in a 464-bed acute care, medical-surgical teaching hospital. There were only five cases during the eight months prior to the outbreak period (P less than 0.0001). Initial measures, including category-specific isolation and education, did not limit the spread of the outbreak of a strain of MRSA. This prompted institution of additional measures including (1) strict isolation of all infected and colonized cases; (2) prospective microbiological surveillance to detect additional cases; (3) multiple site cultures of identified cases to determine the extent of colonization; (4) employee and environment surveillance; (5) antibiotic decolonization of patients and employees; and (6) educational efforts. The highest number of personnel carriers were noted in one of the critical care units where most of the cases occurred. The decolonization protocol was 100% effective for personnel carriers. The incidence of nosocomial cases of MRSA fell to zero in the five months following the implementation of the strategy. The cost of the entire eradication process was approximately half that of treating a single MRSA bacteremia.

Health and economic impacts of antimicrobial resistance

For comparison of the impacts of infections due to antimicrobial-resistant bacteria with those of infections due to antimicrobial-susceptible strains of the same bacteria, data were evaluated from 175 published and unpublished reports of investigations of nosocomial and community-acquired infections with selected bacteria. The evaluation of outcomes of hospital-acquired infections with resistant organisms was often confounded by risk factors also associated with poor outcomes. Nevertheless, for both nosocomial and community-acquired infections, the mortality, the likelihood of hospitalization, and the length of hospital stay were usually at least twice as great for patients infected with drug-resistant strains as for those infected with drug-susceptible strains of the same bacteria. Poor outcomes could be attributed both to the expected effects of ineffective antimicrobial therapy and to the unexpected occurrence of drug-resistant infections complicated by prior antimicrobial therapy for other medical problems. Although the adverse economic and health effects of drug-resistant bacterial infections can only be roughly quantified, it is concluded that antimicrobial resistance is an important health problem and an economic burden to society.

Use of the appropriateness evaluation protocol for estimating the incremental costs associated with nosocomial infections

Existing methods for estimating additional days of hospital stay due to nosocomial infections (NI) have a number of documented limitations. An alternative method described in this paper uses the Appropriateness Evaluation Protocol (AEP) to determine whether each day of acute inpatient care is appropriate based on the need for care of the NI, original cause of hospitalization (OC), or combined NI-OC requirements. Using this method to identify specific days of hospitalization due to Staphylococcus aureus nosocomial infection, we find: 1) length of stay is increased for only a minority of patients (38%); 2) an average of 20 additional days of stay occurred for patients with 1 or more days attributed to NI; and 3) an average of 52% of length of stay of patients with 1 or more days attributed to NI can be attributed to the NI. Application of the AEP-based method is a useful alternative for identifying additional days of stay due to NI.

Benefits and costs of a control program for an epizootic of Staphylococcus aureus mastitis

In response to an epizootic of Staphylococcus aureus mastitis, the owner of a 2,000-cow dairy instituted a treatment, prevention, and control program (hereafter, "intervention program") consisting of teat dipping, bacteriologic culturing of milk from all fresh cows and from cows with clinical signs of infection, and culling cows found to be infected. The program was highly beneficial, yielding $2.40 in direct benefits for every $1 invested.

Prospective microbiologic surveillance in control of nosocomial methicillin-resistant Staphylococcus aureus

A prospective microbiological surveillance (PMS) program was developed in a comprehensive hospital-wide effort for control of nosocomial methicillin-resistant Staphylococcus aureus (MRSA). This PMS program entailed: active identification of colonized and infected patients; application of a screening microbiologic system for MRSA; isolation of colonized and infected patients; antibiotic decolonization of MRSA; and educational efforts. The PMS program was studied over three and one half years for its contribution to infection control of MRSA, early identification of nosocomial MRSA outbreaks, use of the highest yield surveillance culture sites, and cost effectiveness. Following initiation of the PMS program in December 1982, during an MRSA outbreak, the frequency of new MRSA cases declined from 14 to none by the end of a 3-month pilot study. The frequency of new MRSA cases stabilized at approximately 2 per month until October 1983, when the PMS system allowed prompt detection of a new outbreak of 11 cases. Following isolation and antibiotic decolonization, the frequency of cases again declined to 3 per month. A third outbreak in December 1985 again was promptly detected and controlled. Infection to colonization ratio decreased from a maximum of 1.5 during outbreaks to a minimum of 0.17 after outbreaks. Wounds and tracheostomy sites provided the greatest yield of detection of new cases of MRSA. During one 15-month period, 35 of the 43 new cases were detected initially at wounds and tracheostomy sites. No new MRSA cases were detected by a positive axillary or nares site alone. The estimated quarterly cost of outbreaks and infection paralleled the quarterly frequency of new MRSA cases.(ABSTRACT TRUNCATED AT 250 WORDS)