Biomedical subjects
David P Calfee
Publications and source records attributed to David P Calfee.
Prevention and management of occupational exposures to human immunodeficiency virus (HIV).
Occupational exposure to blood and other potentially infectious body fluids places health care workers at risk for acquisition of bloodborne pathogens, including the human immunodeficiency virus (HIV). Utilizing appropriate techniques, personal protective equipment, and safer "sharp" technology can minimize the risk of these exposures. When exposure does occur, immediate evaluation and initiation of post-exposure prophylaxis, when indicated. can substantially reduce the risk of transmission of HIV. In this article, the basic concepts of exposure prevention and management are reviewed.
Short report: asymptomatic Cryptosporidium hominis infection among human immunodeficiency virus-infected patients in Tanzania.
Few data exist on the relative importance of individual Cryptosporidium species in acquired immunodeficiency syndrome cryptosporidiosis. We characterized 127 inpatients infected with human immunodeficiency virus (HIV) in Tanzania for their CD4 cell count and by stool analysis, including Cryptosporidium immunofluorescence and polymerase chain reaction-restriction fragment length polymorphism. Cryptosporidium was detected in patients both with and without diarrheal symptoms (defined as > or = 3 liquid stools/day, 11 of 61 versus 11 of 66; P = not significant) and was a marker for low CD4 cell count (median = 124/microL versus 212/microL in Cryptosporidium-negative patients; P < 0.04). Cryptosporidium hominis was the predominant species in this region and was associated with a longer duration of symptoms, a higher rate of asymptomatic infection, and a lower CD4 cell count versus C. parvum-infected patients (P < 0.05). This study suggests there may be important differences in the natural history of Cryptosporidium infection in HIV-infected persons depending on parasite species.
Control of endemic vancomycin-resistant Enterococcus among inpatients at a university hospital.
We sought to determine the ability of surveillance cultures and isolation of vancomycin-resistant Enterococcus (VRE)-colonized patients to control nosocomial VRE infection and colonization during a 5-year period (November 1994 through October 1999). During this period, VRE colonization was limited to 0.82% of admissions. The incidence of VRE infection was 0.12 cases per 1000 patient-days (attack rate, 0.07%). Colonized patients were first identified by surveillance (95%) or routine clinical cultures (5%); 14% of colonized patients had a positive clinical culture a median of 15 days after a positive surveillance culture. Ten percent of colonized patients were identified by surveillance at the time of transfer from another health care facility. Identification of these colonized patients was associated with reduction from a peak incidence rate of 2.07% to a rate of 1.25% and stabilization at this lower level. The use of surveillance cultures to identify and isolate patients with asymptomatic colonization can provide sustained control of the spread of VRE within a health care facility.
Community-acquired methicillin-resistant Staphylococcus aureus: a meta-analysis of prevalence and risk factors.
Reports suggest that carriage of methicillin-resistant Staphylococcus aureus (MRSA) among persons without health care-associated risks has increased. A meta-analysis of studies reporting the prevalence of community-acquired MRSA (CA-MRSA) among MRSA isolates from hospitalized patients or the prevalence of MRSA colonization among community members was conducted. The CA-MRSA prevalence among hospital MRSA was 30.2% in 27 retrospective studies and 37.3% in 5 prospective studies; 85% of all patients with CA-MRSA had > or =1 health care-associated risk. The pooled MRSA colonization rate among community members was 1.3% (95% confidence interval [CI], 1.04%-1.53%), but there was significant heterogeneity among study populations. Community members from whom samples were obtained in health care facilities were more likely to be carrying MRSA than were community members from whom samples were obtained outside of the health care setting (relative risk, 2.35; 95% CI, 1.56-3.53). Among studies that excluded persons with health care contacts, the MRSA prevalence was 0.2%. Moreover, most persons with CA-MRSA had > or =1 health care-associated risk, which suggests that the prevalence of MRSA among persons without risks remains low (< or =0.24%). Effective control of dissemination of MRSA throughout the community likely will require effective control of nosocomial MRSA transmission.
Spread of methicillin-resistant Staphylococcus aureus (MRSA) among household contacts of individuals with nosocomially acquired MRSA.
OBJECTIVE: To determine the frequency with which methicillin-resistant Staphylococcus aureus (MRSA) is spread from colonized or infected patients to their household and community contacts. DESIGN: Retrospective cohort study. SETTING: University hospital. PARTICIPANTS: Household and community contacts of MRSA-colonized or -infected patients for whom MRSA screening cultures were performed. RESULTS: MRSA was isolated from 25 (14.5%) of 172 individuals. Among the contacts of index patients who had at least one MRSA-colonized contact, those with close contact to the index patient were 7.5 times more likely to be colonized (53% vs 7%; 95% confidence interval, 1.1 to 50.3; P = .002). An analysis of antimicrobial susceptibility and DNA fingerprint patterns suggested person-to-person spread. CONCLUSIONS: MRSA colonization occurs frequently among household and community contacts of patients with nosocomially acquired MRSA, suggesting that transmission of nosocomially acquired MRSA outside of the healthcare setting may be a substantial source of MRSA colonization and infection in the community.
Infection control and cost control in the era of managed care.
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Comparison of four antiseptic preparations for skin in the prevention of contamination of percutaneously drawn blood cultures: a randomized trial.
A number of skin antiseptics have been used to prevent the contamination of blood cultures, but the comparative efficacies of these agents have not been extensively evaluated. We therefore sought to compare the efficacy of four skin antiseptics in preventing blood culture contamination in a randomized, crossover, investigator-blinded study conducted in an emergency department and the inpatient wards of a university hospital. The patient group included all patients from whom blood samples were obtained percutaneously for culture. Skin antisepsis was performed with 10% povidone-iodine, 70% isopropyl alcohol, tincture of iodine, or povidone-iodine with 70% ethyl alcohol (i.e., Persist). The blood culture contamination rate associated with each antiseptic was then determined. A total of 333 (2.62%) of 12,692 blood cultures were contaminated during the study period compared to 413 (3.21%) of 12,859 blood cultures obtained during the previous 12-month period (relative risk = 0.82; 95% confidence interval, 0.71 to 0.94; P = 0.006). During the study, the contamination rates were determined to be 2.93% with povidone-iodine, 2.58% with tincture of iodine, 2.50% with isopropyl alcohol, and 2.46% with Persist (P = 0.62). We detected no significant differences in the blood culture contamination rates among these four antiseptics, although there was some evidence suggesting greater efficacy among the alcohol-containing antiseptics. Among the evaluated antiseptics, isopropyl alcohol may be the optimal antiseptic for use prior to obtaining blood for culture, given its convenience, low cost, and tolerability.