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Biomedical subjects

D E Craven

Publications and source records attributed to D E Craven.

At least 73 records · Page 4Linked to original sources

Bacterial infections in adult patients with the acquired immune deficiency syndrome (AIDS) and AIDS-related complex.

Sixty-four episodes of bacterial infection were identified over a 44-month period in 16 of 28 patients with the acquired immune deficiency syndrome (AIDS) and 14 of 31 patients with AIDS-related complex. Nineteen of the 30 infected patients were parenteral drug abusers, 10 were from Caribbean Islands and had no identified risk factor, and one was a homosexual male. Fourteen patients had 21 episodes of community-acquired pneumonia: Streptococcus pneumoniae (10), Haemophilus influenzae (three), other Haemophilus species (three), group B beta-hemolytic streptococci (one), Staphylococcus aureus (one), Branhamella catarrhalis (one), Legionella pneumophila (one), and Mycoplasma pneumoniae (one). Seven patients had eight episodes of nosocomial pneumonia caused by gram-negative bacilli. Twenty-five episodes of community-acquired bacteremia and nine episodes of nosocomial bacteremia were associated with specific sites of infection. Other infections included meningitis (two), urinary tract infection (one), and abscesses involving subcutaneous and deep tissues (12). Sixteen patients had recurrent infections; 11 of these had or eventually had AIDS. Community-acquired bacterial infections in patients with AIDS or AIDS-related complex are common and may be recurrent but have low fatality rates. In comparison, nosocomial bacterial infections occur primarily in patients with AIDS and have high fatality rates.

AIDS-Related Complex↗

Bacterial colonization in humidifying cascade reservoirs after 24 and 48 hours of continuous mechanical ventilation.

We evaluated levels of bacterial colonization in the humidifying cascade reservoirs of 466 mechanical ventilators; 326 reservoirs were cultured after 24 hours and 140 were cultured after 48 hours of continuous mechanical ventilation. Bacterial colonization was absent in 284 (87.1%) of the humidifier reservoirs sampled at 24 hours and 125 (89.3%) of the reservoirs cultured at 48 hours. Levels of bacterial colonization in the remaining humidifiers were low (less than 100 organisms/mL). The median temperature recorded in the reservoir fluid of 30 different ventilators was 50 degrees C (range 40 degrees to 60 degrees C). In vitro seeding of reservoir fluid at 50 degrees C with 10(6) organisms/mL of four different species of nosocomial gram-negative bacilli and Staphylococcus aureus demonstrated rapid killing of all five strains over a 6-hour incubation period, and no significant bacterial aerosols were detected. Rates and levels of bacteria in heated humidifier reservoirs are low and nosocomial pathogens survive poorly at the median reservoir temperature of 50 degrees C. We conclude that the heated humidifier reservoir on a mechanical ventilator is an unlikely source of colonization or bacterial aerosols, and therefore it can be changed every 48 hours with the ventilator tubing.

Bacteria↗

Two-stage tuberculin testing with control antigens in patients residing in two chronic disease hospitals.

We studied the prevalence of tuberculin reactivity and anergy in 360 elderly patients residing in two municipal chronic disease hospitals. Eighty-five (26%) of the 323 patients tested had a positive reaction to a stage 1 tuberculin test and 12 (6%) of the 207 stage 1 tuberculin-negative patients exhibited a booster response to a stage 2 tuberculin test. Thirty percent of the same 207 patients had no response to an anergy panel of skin test antigens that included candida, mumps, and trichophyton. Nonresponders to tuberculin and the anergy panel had significantly higher one-year mortality rates compared to responders (44 v 20%, P = 0.001). Tuberculin-positivity among the 770 employees working in these facilities was 43%; 12 (4%) had a booster response. A survey of 29 randomly selected long-term care facilities in the Boston area indicated that all had a policy for pre-employment screening of employees, but less than 50% had a policy for patients and only one institution used two-stage testing. Routine tuberculin testing is recommended for long-term care facilities and the two-stage method is preferable in institutions with adequate resources.

Adult↗

M proteins of group G streptococci isolated from bacteremic human infections.

We studied seven strains of group G streptococci isolated from clinically severe bacteremic infections in six intravenous drug abusers. These group G strains multiplied luxuriantly in fresh human blood. On electron microscopy, they exhibited surface fibrillae similar to those observed in M-protein-rich group A streptococci, but they were not serologically M typable with a battery of 39 M antisera. Rabbit antisera raised against two of the group G strains (1618 and 1750) opsonized the homologous but not the heterologous isolates and exhibited type-specific Ouchterlony immunoprecipitin reactions. Moreover, antisera raised against peptic extracts of strain 1750 also promoted phagocytic killing of that strain. Anti-1750 reacted in high titer in an enzyme-linked immunosorbent assay against peptic extracts of the homologous strain; these antibodies were removed by absorption with 1750 cells but not by absorption with heterologous strains. These studies represent, to our knowledge, the first analysis of virulence factors of group G streptococci isolated from invasive human disease. The seven epidemiologically related blood isolates of group G streptococci possess distinct type-specific, antiphagocytic surface virulence factors analogous to the M proteins of group A streptococci.

Antibodies, Bacterial↗

Isolation patterns of the human immunodeficiency virus from cervical secretions during the menstrual cycle of women at risk for the acquired immunodeficiency syndrome.

Human immunodeficiency virus (HIV) has been isolated from both male and female genital secretions. We evaluated the pattern of female genital carriage during the menstrual cycle, and its relationship to HIV viremia. Seven menstruating seropositive women and one seronegative control had cervical secretions and venous blood samples cultured at weekly intervals during a single menstrual cycle. The virus was isolated from cervical secretions in four of seven women. No specific cycle pattern was seen, and positivity for HIV at one site (blood or cervical) did not correlate with positivity at another site. Blood cultures generally, but not always, became positive earlier than cultures from cervical specimens, suggesting higher titers of virus in blood. Thus, HIV secretion may be intermittent. These findings, together with earlier reports, suggest that seropositive women may transmit HIV at any time during the menstrual cycle.

AIDS-Related Complex↗

Nosocomial pneumonia in the intubated patient.

The intubated patient receiving mechanical ventilation is at high risk for nosocomial pneumonia. Epidemiologic data, pathogenic mechanisms, and risk factors for the development of nosocomial pneumonia are reviewed in this subset of patients. Exogenous and endogenous factors for bacterial colonization of the oropharynx are summarized with particular emphasis on the effects of bacterial overgrowth in the stomach. In addition, we review the role of respiratory therapy equipment in the pathogenesis of pneumonia. Overall fatality rates for patients receiving mechanical ventilation in an intensive care unit is approximately 40%. Patients who develop ventilator-associated pneumonia have fatality rates that exceed 50% and are more than two-fold higher than intubated patients without pneumonia. Measures for altering oropharyngeal colonization, reducing gastric colonization, and the use of sound infection control practices are cornerstones for the prevention of ventilator-associated pneumonia.

Cross Infection↗

Nosocomial dermatitis and pruritus caused by pigeon mite infestation.

We report an outbreak of pigeon mite infestation involving two patients, two nurses, and one physician on a medical ward in a municipal hospital. The index patient developed a diffuse, pruritic erythematous maculopapular rash on his trunk and extremities. Dermanyssus gallinae, a nonburrowing, blood-sucking avian mite was identified on the patient and his bedding. A second patient who complained of scalp pruritus had mites present on her pillow and bed linen. The intern taking care of both patients, and two nurses who had contact with these patients, had mite infestation. Pigeons roosting on the air conditioners and near the doors connecting the patients' rooms to a sunporch were the source of the mites. The outbreak abated after control measures were instituted that prevented pigeons from roosting on the porch. This outbreak illustrates an unusual cause of nosocomial pruritic dermatitis that may be misdiagnosed as scabies or pediculosis. Physicians and health care personnel working in metropolitan areas are alerted to mites as a cause of pruritic dermatitis that may be chronic, recurrent, or unresponsive to ectoparasiticides.

Adult↗

Isolation of HTLV-III/LAV from cervical secretions of women at risk for AIDS.

Cervical secretions from 14 women seropositive for HTLV-III/LAV were obtained between days 7 and 21 of the menstrual cycle and cultured for virus. HTLV-III/LAV was isolated from cervical secretions in 4 of 14 women, as well as from blood of 7 of 13 women tested. Female genital secretions may therefore be a source for sexual transmission of the virus to men.

Acquired Immunodeficiency Syndrome↗

Seroprevalence of hepatitis B virus and delta agent in parenteral drug abusers. Immunogenicity of hepatitis B vaccine.

The seroprevalence of hepatitis B virus (HBV) markers and antibody to the delta agent (anti-delta) was determined for 112 parenteral drug abusers entering a methadone maintenance program. Markers of HBV infection were found in 87.5 percent of the group, and seropositivity was significantly associated with duration of drug abuse (p = 0.02). Antibody to the hepatitis B core antigen (anti-HBc) was present in all seropositive subjects; three (2.7 percent) were hepatitis B surface antigen-positive, and 16 (14.2 percent) had only anti-HBc. Five (10.6 percent) of 47 subjects with HBV markers had anti-delta. Anti-delta was more common in subjects who reported multiple symptomatic episodes of hepatitis (p = 0.02) and fewer than three daily drug injections (p = 0.05). Ten susceptible subjects received hepatitis B vaccine, and seroconversion rates at one, three, and six months were 20.0, 88.8, and 100 percent, respectively. The data indicate that hepatitis B vaccine is immunogenic in this population, and that anti-HBc is the optimal prevaccination screening test. Recent outbreaks of fulminant HBV and delta co-infection among drug abusers emphasize the need for early immunization in this group.

Adult↗

Methicillin-resistant Staphylococcus aureus bacteremia linked to intravenous drug abusers using a "shooting gallery".

Over a 15-month period, seven intravenous drug abusers had 10 admissions because of bacteremia due to methicillin-resistant Staphylococcus aureus. Seven episodes of probable bacterial endocarditis occurred in four patients; one patient had septic thrombophlebitis and two had soft tissue infections. All seven patients patronized a local "shooting gallery" where paraphernalia were provided and drugs were often administered by a "street doctor." All isolates were phage type 29/77/83A/84/85 and demonstrated resistance only to methicillin, oxacillin, and penicillin. This strain of methicillin-resistant S. aureus has a phage type and antibiogram that is distinct from nosocomial methicillin-resistant S. aureus and was probably acquired by intravenous drug abusers during visits to the "shooting gallery". The "shooting gallery" is an integral part of the drug culture and a likely source for the transmission of antibiotic-resistant organisms.

Adult↗

Nonresponsiveness to hepatitis B vaccine in health care workers. Results of revaccination and genetic typings.

Twenty-eight health care workers who had a poor antibody response when initially vaccinated with hepatitis B vaccine were revaccinated with three additional 20-microgram doses. Eight of the twenty nonresponders, who had levels of antibody to hepatitis B surface antigen (anti-HBs) of less than 8 estimated radioimmunoassay (RIA) units, and all 8 of the hyporesponders, who had anti-HBs levels of 8 or 16 RIA units, attained anti-HBs levels of 36 RIA units or more after revaccination. Tests for HLA-A, B, C, and DR; for complement proteins C2, C4A, C4B, and BF; and for the erythrocyte enzyme glyoxalase I were done in 17 nonresponders and 3 hyporesponders. Nine (45%) had HLA-DR7 and 8 (40%) had HLA-DR3, compared with an expected rate of 23% in the general population. At least one of two extended haplotypes (B44, DR7, FC31 or B8, DR3, SCO1) were detected in 6 of the 9 who did not respond to revaccination, compared with 2 of 11 who responded to a second course of vaccine. Poor responders to vaccine may benefit from revaccination, and genetic factors may modulate the immune response to vaccination.

Adult↗

Risk factors for pneumonia and fatality in patients receiving continuous mechanical ventilation.

We studied risk factors for nosocomial pneumonia and fatality in 233 intensive care unit patients requiring continuous mechanical ventilation. Ventilator-associated pneumonia was diagnosed in 49 (21%) of the 233 patients. Of the 8 risk factors univariately associated with the development of pneumonia, only the presence of an intracranial pressure monitor (p less than 0.002), treatment with cimetidine (p less than 0.01), hospitalization during fall-winter seasons (p less than 0.04), and mechanical ventilator circuit changes every 24 h rather than every 48 h (p less than 0.02) remained significant after stepwise logistic regression. The overall fatality rate for the 49 patients who developed ventilator-associated pneumonia was 55%. Ventilator-associated pneumonia was 1 of 18 variables univariately associated with overall patient fatality, but it was not among the 7 variables present after multivariate analysis. The data delineate risk factors associated with the development of nosocomial pneumonia and fatality in patients receiving continuous mechanical ventilation.

Adult↗

A randomized study comparing a transparent polyurethane dressing to a dry gauze dressing for peripheral intravenous catheter sites.

We studied rates of peripheral intravenous (IV) catheter tip and insertion site colonization after randomly assigning patients to transparent polyurethane (TP) dressings (N = 316) or dry gauze (DG) dressings (N = 421). The study was conducted during both summer and fall seasons, in a facility which lacked air conditioning. All patients had a teflon plastic catheter inserted, maintained and cultured by a member of the IV therapy team; no antibiotic or antiseptic ointments were used. Colonization rates were higher in the summer than in the fall for both catheter tips (9.0% vs 3.5%, p = 0.005) and sites (21.6% vs 7.0%, p = 0.001). During the summer season, the rate of catheter tip colonization with TP dressings was nearly twice that of DG dressings (12.4% vs 6.8%, p = 0.04). Logistic regression analysis indicated that catheter tip colonization was associated with the summer season (odds ratio = 3.0, 95% CI 1.4-6.2) and TP dressings (odds ratio = 1.8, 95% CI 1.1-3.2), and that site colonization was associated with both summer (odds ratio = 4.0, 95% CI 2.2-7.1) and receipt of antibiotics (odds ratio = 1.9, 95% CI 1.1-3.2). Coagulase-negative staphylococci were isolated from 55.5% of the colonized catheter tips and insertion sites. The data suggest that bacterial colonization of peripheral IV catheters is increased in summer, and that use of TP dressings may increase both tip colonization and cost nearly twofold.

Bacterial Infections↗

Occupational hazards to hospital personnel.

Hospital personnel are subject to various occupational hazards. Awareness of these risks, compliance with basic preventive measures, and adequate resources for interventions are essential components of an occupational health program. Physical, chemical, and radiation hazards; important infectious risks; and psychosocial problems prevalent in hospital workers are reviewed. A rational approach to managing and preventing these problems is offered.

Accidents, Occupational↗

Isolated antibody to hepatitis B surface antigen and response to hepatitis B vaccination.

To determine the need for immunization of health workers with antibody to hepatitis B surface antigen (anti-HBs) as their only serologic marker of previous hepatitis B exposure, we studied the level, persistence, and immunologic specificity of isolated anti-HBs in 46 persons identified during screening for hepatitis B vaccine. We rescreened these persons 1 year later, administered a single dose of hepatitis B vaccine, and determined the anti-HBs level at 1, 2, and 8 weeks after vaccination. Isolated anti-HBs levels were low and antibody did not persist; 22 subjects tested had lost detectable anti-HBs within 19 months even though immunologic specificity was shown in vitro in 34. Anamnestic responses suggesting previous exposure and immunity were seen in only 10 subjects; 5 of these subjects had moderate-level, persistent anti-HBs. Although some persons with naturally acquired, isolated anti-HBs may be protected from hepatitis B, the immunologic specificity and protective value of anti-HBs, especially when levels are low, remain questionable.

Antibody Specificity↗