Prospective study of etiologic agents of community-acquired pneumonia in patients with HIV infection.

OBJECTIVES: To study prospectively HIV-positive patients admitted to the hospital because of pneumonia by extensive laboratory tests to determine specific microbiologic diagnoses and to establish the best clinical diagnosis after review of all available data by expert clinicians. METHODS: Patients admitted to one of two hospitals had extensive questionnaires completed and defined diagnostic tests performed on blood, sputum, urine and bronchoalveolar lavage specimens, when available. RESULTS: A total of 230 patients had a diagnosis of pneumonia verified. A definite or probable etiologic diagnosis was made in 155 (67%) of these patients. Pneumocystis carinii caused 35% of all cases of pneumonia. Twenty-seven percent of cases of pneumonia with a single etiology had a definite or probable bacterial etiology. 'Atypical agents' were distinctly uncommon. Few clinical or laboratory parameters could differentiate specific etiologies. CONCLUSIONS: P. carinii continues to be a common cause of pneumonia in these patients. The rarity of 'atypical agents' could simplify the empiric approach to therapy. Despite the use of extensive testing we did not find a definite etiology in a large number of cases.

Bioterrorism-related inhalational anthrax: the first 10 cases reported in the United States.

From October 4 to November 2, 2001, the first 10 confirmed cases of inhalational anthrax caused by intentional release of Bacillus anthracis were identified in the United States. Epidemiologic investigation indicated that the outbreak, in the District of Columbia, Florida, New Jersey, and New York, resulted from intentional delivery of B. anthracis spores through mailed letters or packages. We describe the clinical presentation and course of these cases of bioterrorism-related inhalational anthrax. The median age of patients was 56 years (range 43 to 73 years), 70% were male, and except for one, all were known or believed to have processed, handled, or received letters containing B. anthracis spores. The median incubation period from the time of exposure to onset of symptoms, when known (n=6), was 4 days (range 4 to 6 days). Symptoms at initial presentation included fever or chills (n=10), sweats (n=7), fatigue or malaise (n=10), minimal or nonproductive cough (n=9), dyspnea (n=8), and nausea or vomiting (n=9). The median white blood cell count was 9.8 X 10(3)/mm(3) (range 7.5 to 13.3), often with increased neutrophils and band forms. Nine patients had elevated serum transaminase levels, and six were hypoxic. All 10 patients had abnormal chest X-rays; abnormalities included infiltrates (n=7), pleural effusion (n=8), and mediastinal widening (seven patients). Computed tomography of the chest was performed on eight patients, and mediastinal lymphadenopathy was present in seven. With multidrug antibiotic regimens and supportive care, survival of patients (60%) was markedly higher (<15%) than previously reported.

Possible horizontal transfer of the vanB2 gene among genetically diverse strains of vancomycin-resistant Enterococcus faecium in a Korean hospital.

A total of 25 isolates of vanB-containing Enterococcus faecium were recovered from patients in a single Korean hospital over a 20-month period. There were two distinct vanB2 patterns among the 11 pulsed-field gel electrophoresis types; 17 contained the prototype vanB2 and 8 contained a novel vanB2 with a 177-bp deletion in vanY(B). Both vanB2 genes were transmissible in vitro at a mean frequency of 1.1 x 10(-8) transconjugants/donor. These results suggest the horizontal spread of vanB2 is occurring among genetically diverse strains of E. faecium in Korean hospitals.

Incubation period and sources of exposure for cutaneous Mycobacterium marinum infection: case report and review of the literature.

The diagnosis of cutaneous Mycobacterium marinum infection is often delayed for months after presentation, perhaps because important clinical clues in the patient's history are frequently overlooked. Knowledge of the incubation period allows the clinician to target questions about the patient's history. Prompted by a case with a prolonged incubation period, we sought to determine more precisely the incubation period of M. marinum infection. The MEDLINE database for the period 1966-1996 was searched for information regarding incubation period and type of exposure preceding M. marinum infection. Ninety-nine articles were identified, describing 652 cases. Forty cases had known incubation periods (median, 21 days; range, 5-270 days). Thirty-five percent of cases had an incubation period > or =30 days. Of 193 infections with known exposures, 49% were aquarium-related, 27.4% were related to fish or shellfish injuries, and 8.8% were related to injuries associated with saltwater or brackish water. Because the incubation period for cutaneous M. marinum infection can be prolonged, patients with atypical cutaneous infections should be questioned about high-risk exposures that may have occurred up to 9 months before the onset of symptoms.

Association between mucositis severity and vancomycin-resistant enterococcal bloodstream infection in hospitalized cancer patients.

OBJECTIVE: To determine the role of mucositis severity in the development of vancomycin-resistant enterococcal (VRE) bloodstream infection (BSI). SETTING: A tertiary-care university medical center. PARTICIPANTS: Hematology-oncology-unit inpatients. DESIGN: Patients with VRE BSI (case-patients) were compared with VRE-colonized (control) patients from September 1994 through August 1997. Oral mucositis severity was recorded on the day of VRE BSI for case-patients and on hospital day 22 (median day of hospitalization of case-patient VRE BSI) for controls. There were 19 case-patients and 31 controls. RESULTS: In univariate analysis, case-patients were significantly more likely than controls to have a higher mucositis severity score, diarrhea, or a higher severity of illness score. In multivariate analysis, only mucositis remained as an independent risk factor, and increasing mucositis score was significantly associated with VRE BSI. CONCLUSIONS: Mucositis severity was independently associated with an increasing risk for VRE BSI. Interventions to alter mucositis severity may help to prevent VRE BSI in hospitalized cancer patients.

A randomized crossover study of disposable thermometers for prevention of Clostridium difficile and other nosocomial infections.

OBJECTIVE: To test the hypothesis that use of disposable thermometers would result in lower rates of nosocomial Clostridium difficile diarrhea and of total nosocomial infections, compared with electronic thermometers. DESIGN: Prospective randomized crossover trial. SETTING: A 700-bed university hospital providing primary and tertiary care. PATIENTS: All patients admitted to a group of 20 inpatient nursing units. INTERVENTIONS: 20 nursing units were randomized into two groups. One group randomly was assigned exclusive use of single-use disposable thermometers for patient temperature measurement, and the other group was assigned exclusive use of electronic thermometers. After 6 months, the assignments were reversed. MAIN OUTCOME MEASURES: Rates of C difficile infections, total nosocomial diarrheal episodes, and total nosocomial infections were prospectively followed in each study unit over 11 months. RESULTS: 26,350 patients were admitted to the study units and hospitalized for 120,529 patient days. There were 947 nosocomial infections (7.86 per 1,000 patient days). Nosocomial C difficile-associated diarrhea defined by positivity to both toxin B (titer > or = 1:10) and toxin A was detected in 32 patients (3.4% of all nosocomial infections). A significantly lower rate of nosocomial C difficile-associated diarrhea was observed with disposable thermometer use (0.16 per 1,000 patient days) compared with electronic thermometer use (0.37 per 1,000 patient days, relative risk [RR] = 0.44; 95% confidence interval [CI95], 0.21-0.93, P = .026). There was no difference in overall rates of nosocomial infection between the disposable and electronic groups (8.03 and 7.68 infections per 1,000 patient days, respectively; RR, 1.04; CI95, 0.92-1.19; P = .52) or in the overall rate of nosocomial diarrhea (3.34 and 3.40 per 1,000 patient days, respectively; RR, .98; CI95, 0.81-1.19; P = .87). CONCLUSIONS: The incidence of nosocomial C difficile diarrhea was reduced significantly by using single-use, disposable thermometers as compared with electronic thermometers, but there was no effect on either the overall rate of nosocomial diarrhea or the rate of total nosocomial infections.

Effectiveness of contact isolation during a hospital outbreak of methicillin-resistant Staphylococcus aureus.

Contact isolation has been recommended by the Centers for Disease Control and Prevention for the prevention of nosocomial transmission of methicillin-resistant Staphylococcus aureus (MRSA), but there are few data which prospectively quantitate the effectiveness of contact isolation for this purpose. During an outbreak of MRSA in a neonatal intensive care unit between July 18, 1991 and January 30, 1992, weekly surveillance cultures were performed on all patients. Sixteen of 331 admissions became colonized with MRSA, and 3 (19%) developed infections: bacteremia, conjunctivitis, and dialysis catheter site infection. The isolates from all 16 patients were submitted to plasmid profile analysis and restriction enzyme analysis of whole cell DNA. All of the patients had identical chromosomal patterns and plasmid profiles, which differed from control isolates from other wards, indicating that the outbreak resulted from spread of a unique strain. None of 144 personnel who were cultured after recent contact with newly colonized patients during the outbreak were found to carry MRSA, which suggests that patients were the reservoir for transmission rather than caregivers. The most probable source for each individual transmission was determined based on proximity in time and space and shared exposure to caregivers. The rate of transmission of MRSA from patients on contact isolation was significantly lower (0.009 transmissions per day on isolation) than the rate for patients not on isolation (0.140 transmissions per day unisolated, relative risk = 15.6, 95% confidence interval 5.3-45.6, p < 0.0001). The authors conclude that the risk of nosocomial transmission of MRSA was reduced 16-fold by contact isolation during the outbreak in this neonatal intensive care unit. These data confirm the results of previous studies which have suggested that contact isolation was effective in controlling the epidemic spread of methicillin-resistant Staphylococcus aureus.

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.

Mycobacterium tuberculosis transmission rates in a sanatorium: implications for new preventive guidelines.

BACKGROUND: In 1990, the Centers for Disease Control and Prevention recommended substituting dust-mist particulate respirators for simple isolation masks in acid-fast bacillus isolation rooms, reasoning that air leaks around the simple masks could result in a higher rate of purified protein derivative skin-test conversion. In 1993, a Centers for Disease Control and Prevention draft guideline proposed that high-efficiency particulate air filter respirators be used instead of dust-mist particulate respirators. Epidemiologic data were not available to assess the importance of these changes or their cost-effectiveness. METHODS: The University of Virginia was affiliated with a tuberculosis hospital from 1979 until 1987. We surveyed physicians who had served as residents in internal medicine during this period regarding purified protein derivative skin-test history. duration of work at the tuberculosis sanatorium, and any history of unprotected exposures to patients with active pulmonary or laryngeal tuberculosis. Patients with active tuberculosis at the sanatorium were isolated in negative-pressure rooms with UV lights. Physicians wore simple isolation masks in these rooms. RESULTS: Responses were received from 83 former resident physicians. Fifty-two physicians had worked on the tuberculosis wards for a total of 420 weeks, with no subsequent skin-test conversions (95% CI 0 to 1 conversion/8 physician-years). CONCLUSIONS: These data document a low risk of occupational transmission of Mycobacterium tuberculosis to physicians who wear simple isolation masks in negative-pressure ventilation rooms with UV lights. This low rate predicts that the additional protective efficacy and cost-effectiveness of the more expensive high-efficiency particulate air filter respirators and the respiratory protection program will be low.

Short-course therapy of catheter-related Staphylococcus aureus bacteremia: a meta-analysis.

OBJECTIVE: To determine, through structured methodologic review of published articles, the effectiveness of short-course (< or = 2 weeks) antibiotic therapy for catheter-related Staphylococcus aureus bacteremia. DATA SOURCES: English-language publications on catheter-related S. aureus bacteremia identified using MEDLINE (1966 to the present) and bibliographic review of relevant articles and textbooks. STUDY SELECTION: Any study reporting outcome data for patients with catheter-related S. aureus bacteremia who were treated with short-course therapy. DATA EXTRACTION: Epidemiologic criteria were applied to assess the quality of protection provided by each study against four important types of biases. In addition, the statistical precision of each study was assessed. DATA SYNTHESIS: Eleven studies were identified. Reported late complication rates varied from 0% to 29%; the pooled estimate of the late complication rate was 6.1% (95% Cl, 2.0% to 10.2%). Ten of the 11 studies were uncontrolled. Only three provided adequate protection against treatment allocation bias. None of the studies adequately defined the illness under study, and only four provided adequate follow-up. The relapse rates in all 11 studies had low statistical precision. The complication and mortality rates for catheter-related S. aureus bacteremia when published data were pooled, regardless of duration of therapy, were 24% and 15%, respectively. CONCLUSIONS: The available data regarding the safety of short-course therapy for catheter-related S. aureus bacteremia are potentially flawed by both bias and statistical imprecision. The optimal duration of treatment remains unknown. Short-course therapy should be viewed with caution in treating this serious infection until randomized trials determine the comparative rates of late complication.

Adenovirus type 8 epidemic keratoconjunctivitis in an eye clinic: risk factors and control.

Epidemic keratoconjunctivitis (EKC) due to adenovirus type 8 affected 126 (7%) of 1870 ophthalmology clinic patients during an outbreak. Risk factors and mode of transmission were studied by comparing cases (n = 58) and controls (n = 200) for exposure to risk factors. Pneumotonometry (odds ratio [OR], 10.5; 95% confidence interval [CI], 4.0-27.7), multiple clinic visits (OR, 5.9; 95% CI, 3.3-10.6), and contact with an infected physician (OR, 3.3; 95% CI, 1.2-9.0) were significant risk factors for infection. The hands of 3 patients and 3 physicians with EKC were cultured before and after hand washing to assess adenovirus removal; 3 had hand cultures positive for adenovirus after hand washing. In conclusion, this outbreak appeared to be due to inadequate disinfection of instruments, especially pneumotonometers, and finger-to-eye transmission by health care workers. Hand washing did not reliably remove adenovirus from contaminated fingers. Gloving for exam of eyes with EKC may help prevent transmission. Ophthalmologists with EKC were a significant risk factor for patients and should be furloughed for the duration of communicability.

Decision-making ability and advance directive preferences in nursing home patients and proxies.

We studied 39 nursing home patients and proxies to assess their decision-making capability and preferences regarding advance directives (ADs) or "living wills." Most patients willingly stated preferences; over half opted to forego burdensome measures when death appeared imminent. Patients perceived as decisionally capable were more likely to forego life-sustaining measures than those of questionable capability. The vast majority of proxies disapproved of using life-sustaining measures, even in some cases with limited knowledge of patients' preferences.

Serum phenobarbital concentration predictions by a personal computer software system.

The ability of a personal computer software system to predict actual serum phenobarbital concentrations (SPC) in outpatients taking phenobarbital chronically was assessed by comparing actual with predicted SPC for accuracy, bias, and precision. Data for a four-year period were collected on patients at an outpatient clinic's pharmacokinetic consultation service. The study group included 50 adults and children with at least one SPC taken at a known time after dose administration. Input variables were weight, sex, height, age, concomitant drugs and diseases, phenobarbital dosage regimen, and the time and reported value of all SPC. Initially, SIMKIN (SIMulated KINetics) simulated dosing regimens on the basis of literature estimates of pharmacokinetic parameters; SPC were then estimated for these regimens and compared with actual values. One or two additional SPC were added to the input data and analyzed, and the predicted SPC compared with actual values. Although SIMKIN's accuracy and bias as measured by regression analysis and mean prediction error, respectively, were within clinically acceptable limits, the precision was not. However, these results are limited by the population studied. Patient compliance, concomitant phenytoin therapy, changes in phenobarbital pharmacokinetic parameters with chronic dosing, and disease interactions may significantly affect predictive ability. The clinical effects of these factors need to be evaluated to further improve predictions.