Methicillin-resistant Staphylococcus aureus disease in three communities.

BACKGROUND: Methicillin-resistant Staphylococcus aureus (MRSA) infection has emerged in patients who do not have the established risk factors. The national burden and clinical effect of this novel presentation of MRSA disease are unclear. METHODS: We evaluated MRSA infections in patients identified from population-based surveillance in Baltimore and Atlanta and from hospital-laboratory-based sentinel surveillance of 12 hospitals in Minnesota. Information was obtained by interviewing patients and by reviewing their medical records. Infections were classified as community-associated [correction] MRSA disease if no established risk factors were identified. RESULTS: From 2001 through 2002, 1647 cases of community-associated [correction] MRSA infection were reported, representing between 8 and 20 percent of all MRSA isolates. The annual disease incidence varied according to site (25.7 cases per 100,000 population in Atlanta vs. 18.0 per 100,000 in Baltimore) and was significantly higher among persons less than two years old than among those who were two years of age or older (relative risk, 1.51; 95 percent confidence interval, 1.19 to 1.92) and among blacks than among whites in Atlanta (age-adjusted relative risk, 2.74; 95 percent confidence interval, 2.44 to 3.07). Six percent of cases were invasive, and 77 percent involved skin and soft tissue. The infecting strain of MRSA was often (73 percent) resistant to prescribed antimicrobial agents. Among patients with skin or soft-tissue infections, therapy to which the infecting strain was resistant did not appear to be associated with adverse patient-reported outcomes. Overall, 23 percent of patients were hospitalized for the MRSA infection. CONCLUSIONS: Community-associated MRSA infections are now a common and serious problem. These infections usually involve the skin, especially among children, and hospitalization is common.

Excess costs of hospital care associated with neonatal candidemia.

BACKGROUND: Nosocomial bloodstream infections are associated with increased hospital costs in adult and pediatric patients. Candida is an increasingly important nosocomial pathogen within intensive care nurseries. The purpose of this study was to determine the attributable cost of candidemia in neonates. METHODS: This case-control study included all neonates with candidemia receiving care in hospitals in Connecticut and in Baltimore County and the city of Baltimore, MD. We identified 47 cases and 130 control patients. Multivariable linear regression was used to control for state, birth weight and mortality to determine the effect of candidemia on length of stay, cost per day and total hospital costs. RESULTS: Candidemia was associated with a $28,000 increase in total hospital costs in multivariable analysis. This increase in total cost was the result of both an increase in costs per day and length of hospital stay. Other cost-increasing variables included in the analysis were: state of origin (Connecticut), survival and decreasing birth weight. CONCLUSIONS: This represents the first study of the adjusted costs of candidemia in neonates. In addition to high mortality, candidemia was associated with increased hospital costs. This cost analysis could be helpful in determining the financial benefits of preventing candidemia in high risk neonates.

Epidemiology of community-onset candidemia in Connecticut and Maryland.

BACKGROUND: Almost one-third of patients with bloodstream infections with Candida species (candidemia) have onset of disease that occurs outside of the hospital or < or = 2 days after hospital admission (i.e., community-onset candidemia). We compared the characteristics of patients who developed candidemia by the timing of onset of infection. METHODS: Incident episodes of candidemia were identified through active, population-based surveillance in Connecticut and in Baltimore and Baltimore County, Maryland, during 1 October 1998-30 September 2000. The molecular subtypes of a sample of 45 Candida parapsilosis isolates were evaluated using Southern blots hybridized with the complex probe Cp3-13. RESULTS: Overall, 356 (31%) of the 1143 incident episodes of candidemia were classified as community-onset disease (occurring < or = 2 days after hospital admission), and 132 (37%) were caused by Candida albicans, 89 (25%) were caused by Candida glabrata, 57 (16%) were caused by C. parapsilosis, and 53 (15%) were caused by Candida tropicalis. Community-onset disease was less likely to be associated with concurrent immunosuppressive therapy, recent surgery, or use of a central venous catheter, compared with inpatient disease. Among patients with community-onset disease, the median time from blood culture to initiation of antifungal treatment was 2.7 days, the 30-day case-fatality rate was 26%, and 262 patients (75%) had been hospitalized at least once in the previous 3 months. Although there were few differences between patients with very recent hospitalization (in the previous 1 month), less recent hospitalization (previous 1-3 months), and no documented past hospitalization, C. parapsilosis was more frequently associated with community-onset disease as hospitalization became more distant. C. parapsilosis strains tended to be unique to the patient, with little similarity found between strain types, on the basis of epidemiologic classification of patients. CONCLUSION: We report that community-onset candidemia is common and occurs in patients with extensive contact with the health care system. Disease caused by C. parapsilosis tends to involve unique strains.

Determining risk factors for candidemia among newborn infants from population-based surveillance: Baltimore, Maryland, 1998-2000.

BACKGROUND: Our objective was to determine risks factors for late onset candidemia, independent of birth weight, in newborn infants. METHODS: We performed a matched case-control study. Cases were identified through active, population-based surveillance for candidemia, conducted in Baltimore City and County during 1998-2000, and were defined as the incident isolation of any Candida species from the bloodstream of an infant 3 months old or younger. Four controls, matched by age, hospital, birth weight category, hospital stay and admission date, were selected for each case. Potential risk factors included clinical, demographic and maternal prenatal data. RESULTS: Of the 35 cases, 19 (54%) infections were with Candida albicans, 9 (26%) were with Candida parapsilosis and 5 (14%) were with Candida glabrata. Cases had a median birth weight of 680 g (range, 430-3200 g); median gestational ages of cases and controls were 25 and 27 weeks, respectively. Compared with controls, cases had significant higher mortality (20% versus 4%; P = 0.004). No maternal factors were associated with increased risk of disease; cases were as likely as controls to be of black race. Multivariable conditional logistic regression analysis revealed that gestational age younger than 26 weeks [adjusted odds ratio, 6.5; 95% confidence interval (95% CI), 1.3-32], vaginal delivery (adjusted odds ratio, 4.3; 95% CI 1.3-14.2) and abdominal surgery (adjusted odds ratio, 10.9; 95% CI 1.9-62) were independently associated with increased risk of candidemia. CONCLUSIONS: Independent of birth weight, infants born at <26 weeks or those who have had abdominal surgery are at a significantly increased risk of candidemia. This study helps define a subgroup of preterm infants at high risk of developing bloodstream infections with Candida species.

Antigenic shift and increased incidence of meningococcal disease.

BACKGROUND: The incidence of serogroup C and Y meningococcal disease increased in the United States during the 1990s. The cyclical nature of endemic meningococcal disease remains unexplained. The purpose of this study was to investigate the mechanisms associated with the increase in the incidence of meningococcal disease. METHODS: We characterized an increasing incidence of invasive serogroup C and Y meningococcal disease using population-based surveillance from 1992 through 2001. Isolates were characterized by multilocus sequence typing and antigen sequence typing of 3 outer membrane protein (OMP) genes: porA variable regions (VRs) 1 and 2, porB, and fetA VR. RESULTS: For both serogroups, OMP antigenic shifts were associated with increased incidence of meningococcal disease. For serogroup Y, antigenic shift occurred through amino acid substitutions at all 3 OMPs--PorA VR 1 and 2, PorB, and FetA VR. For serogroup C, antigenic shift involved amino acid substitutions at FetA VR and, in some cases, deletion of the porA gene. On the basis of deduced amino acid sequences, the antigenic changes likely occurred by horizontal gene transfer. CONCLUSIONS: Antigenic shifts were associated with increased incidence of serogroup C and serogroup Y meningococcal disease. For serogroup Y, the changes involved all OMP genes that were studied. Increases in the incidence of meningococcal disease may be caused, in part, by antigenic shift.

Incidence of bloodstream infections due to Candida species and in vitro susceptibilities of isolates collected from 1998 to 2000 in a population-based active surveillance program.

To determine the incidence of Candida bloodstream infections (BSI) and antifungal drug resistance, population-based active laboratory surveillance was conducted from October 1998 through September 2000 in two areas of the United States (Baltimore, Md., and the state of Connecticut; combined population, 4.7 million). A total of 1,143 cases were detected, for an average adjusted annual incidence of 10 per 100,000 population or 1.5 per 10,000 hospital days. In 28% of patients, Candida BSI developed prior to or on the day of admission; only 36% of patients were in an intensive care unit at the time of diagnosis. No fewer than 78% of patients had a central catheter in place at the time of diagnosis, and 50% had undergone surgery within the previous 3 months. Candida albicans comprised 45% of the isolates, followed by C. glabrata (24%), C. parapsilosis (13%), and C. tropicalis (12%). Only 1.2% of C. albicans isolates were resistant to fluconazole (MIC, > or = 64 microg/ml), compared to 7% of C. glabrata isolates and 6% of C. tropicalis isolates. Only 0.9% of C. albicans isolates were resistant to itraconazole (MIC, > or = 1 micro g/ml), compared to 19.5% of C. glabrata isolates and 6% of C. tropicalis isolates. Only 4.3% of C. albicans isolates were resistant to flucytosine (MIC, > or = 32 microg/ml), compared to < 1% of C. parapsilosis and C. tropicalis isolates and no C. glabrata isolates. As determined by E-test, the MICs of amphotericin B were > or = 0.38 microg/ml for 10% of Candida isolates, > or =1 microg/ml for 1.7% of isolates, and > or = 2 microg/ml for 0.4% of isolates. Our findings highlight changes in the epidemiology of Candida BSI in the 1990s and provide a basis upon which to conduct further studies of selected high-risk subpopulations.