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Biomedical subjects

D E Craven

Publications and source records attributed to D E Craven.

At least 55 records · Page 3Linked to original sources

Mycobacterium gordonae: a possible opportunistic respiratory tract pathogen in patients with advanced human immunodeficiency virus, type 1 infection.

STUDY OBJECTIVE: To determine if Mycobacterium gordonae is an opportunistic respiratory tract pathogen in patients infected with human immunodeficiency virus, type 1 (HIV-1). DESIGN: Retrospective review of medical records of all patients with positive cultures for M gordonae from 1987 to 1989. PATIENTS: Fifteen patients had positive sputum cultures for M gordonae: five patients had AIDS or had HIV-1 infections with less than or equal to 180 CD4 cells/cu mm, and ten patients had no clinical evidence of HIV-1 infection. RESULTS: Three of the five HIV-1 infected patients had clinical, roentgenographic, and microbiologic evidence of pulmonary infection due to M gordonae that responded to antimycobacterial therapy. One of the two remaining HIV-1 infected patients had disseminated M tuberculosis and possible coinfection with M gordonae, and the other was lost to follow-up. None of the ten patients without evidence of HIV-1 infection was considered to have M gordonae respiratory tract infection. CONCLUSIONS: Sputum isolates of M gordonae should be considered potential opportunistic respiratory tract pathogens in patients with advanced HIV-1 infection and with otherwise unexplained pulmonary infection.

Acquired Immunodeficiency Syndrome↗

Knowledge about HIV and behavioral risks of foreign-born Boston public school students.

In 1990, 3049 Boston public middle and high school students were surveyed anonymously in English, Spanish, Vietnamese, Chinese, French, or Haitian Creole. Significantly fewer immigrant students, 35% of those surveyed, knew the principal modes of human immunodeficiency virus transmission. Fewer immigrants reported having sexual intercourse (31% vs 53% of nonimmigrants), but among the sexually active only 38% always used condoms, and more immigrants reported intercourse with intravenous drug users (4% vs 1% of non-immigrants). AIDS education should be taught to immigrant students in their native languages.

Adolescent↗

Use of paper-absorbed fingerstick blood samples for studies of antibody to human immunodeficiency virus type 1 in intravenous drug users.

The suitability of paper-absorbed (PA) fingerstick blood specimens for antibody testing of human immunodeficiency virus type 1 (HIV-1) was examined in two populations of intravenous drug users (IVDU): 393 persons from a drop-in counseling and testing clinic and 145 from a methadone treatment clinic. From the first group, the same 66 immunoblot-confirmed enzyme immunoassay (EIA)-positive specimens were identified in sera from venipuncture and parallel fingerstick PA specimens. The latter had slightly higher EIA mean background levels resulting in 10 immunoblot-negative EIA-positive samples versus 6 in the sera group. HIV-1 seroprevalence was 17% of 393 from the drop-in clinic. By category of IVDU, the rates were 34% and 14% for active and recovering IVDU, respectively (P less than .001), and 36% in black and Latino compared with 13% in white IVDU (P less than .002). Of the 145 participants in the methadone program, 39% had antibody to HIV-1: 49% for blacks and Latinos compared with 30% in whites (P less than .01). The data indicate that antibody testing for HIV-1 by PA is equivalent to the serum antibody assay of venipuncture specimens. The fingerstick method appears to have greater use for serosurveys and screening programs because of convenience, safety, and ease of storage, transport, and processing of samples.

AIDS Serodiagnosis↗

Bacteremia due to Mycobacterium tuberculosis in patients with human immunodeficiency virus infection. A report of 9 cases and a review of the literature.

Mycobacterium tuberculosis bacteremia is being reported more frequently in patients with human immunodeficiency virus, type 1 (HIV-1) infection. We report 9 patients with bacteremia due to M. tuberculosis and HIV infection who were identified over a 36-month period. Of the 9 patients studied, 8 were male, 8 were black, 6 were born in Haiti, 3 were homeless, 2 were intravenous drug users, and 1 was homosexual. At the time of diagnosis, 3 patients had the acquired immunodeficiency syndrome (AIDS) and 5 patients had CD4 lymphocyte counts less than or equal to 170 cells/mm3, indicating marked immunodeficiency. All 9 patients presented with temperature greater than 38.3 degrees C, 5 (50%) had abnormal chest roentgenogram on admission, and each of the patients tested had elevations of at least 2 liver function tests. Eight patients (80%) had M. tuberculosis isolated from sputum or other body fluids and tissues. All blood isolates of M. tuberculosis were identified from Dupont Isolator tubes. Antibiotic-resistant isolates of M. tuberculosis were cultured from 3 of the 6 patients born in Haiti. One patient died before diagnosis and received no antimycobacterial therapy; 7 of the remaining 8 patients appeared to respond to treatment. Our data, and a review of the literature, suggest that bacteremia due to M. tuberculosis is becoming more frequent, and that blood cultures may be helpful in establishing or confirming a diagnosis of tuberculosis in patients with HIV-1 infection.

Acquired Immunodeficiency Syndrome↗

Nosocomial pneumonia in the 1990s: update of epidemiology and risk factors.

Hospital-acquired pneumonia is the second most common nosocomial infection in the United States. Aspiration appears to be the major route for the entry of microorganisms into the lower respiratory tract. Nosocomial pneumonia may be caused by bacteria, viruses and fungi. Aerobic gram-negative bacilli and Staphylococcus aureus are the most common etiologic agents, but infection is usually polymicrobial. Risk factors for nosocomial pneumonia include host variables, colonization with nosocomial pathogens, and impaired response of pulmonary defenses to the microbial challenge. Bacteria causing nosocomial pneumonia may be part of the patient's endogenous flora, originate from the hands of hospital personnel, or result from the use of invasive devices. The mechanically ventilated patient has multiple risk factors that contribute to the high rate of nosocomial pneumonia. An understanding of the epidemiology and risk factors for nosocomial pneumonia is fundamental for implementation of preventive strategies to reduce patient morbidity, mortality, and hospital costs.

Cross Infection↗

Genetic prediction of nonresponse to hepatitis B vaccine.

In previous studies of the antibody response to hepatitis B vaccine in 598 subjects who received a full course of vaccination, we observed a bimodal response, with about 14 percent producing less than approximately 1000 radioimmunoassay (RIA) units. An analysis of the major histocompatibility complex (MHC) HLA and complement types of 20 of the subjects with the lowest responses indicated a greater-than-expected number of homozygotes for the extended or fixed MHC haplotype [HLA-B8, SC01, DR3]. This finding suggested that the lack of a normal response was a recessive MHC-linked trait. In this study, we prospectively vaccinated five homozygotes and nine heterozygotes for this haplotype in the expectation that the homozygotes would produce much lower levels of antibody than the heterozygotes. When the antibody response was assessed two months after the third injection, four of the five homozygotes had produced very low levels (approximately 1000 units or less) of antibody (mean, 467 RIA units; range, less than 8 to 1266), whereas all nine heterozygotes produced more than 2500 RIA units (mean, 15,608; range, 2655 to 28,900) (P less than 0.01). We conclude that the usual response to hepatitis B surface antigen is due to the presence of a dominant immune-response gene in the MHC and that a low response is due to the absence of such a gene and the presence on both chromosomes of MHC haplotypes (such as [HLA-B8, SC01, DR3]) that indicate such a response.

Adolescent↗

Nosocomial pneumonia in the intubated patient: role of gastric colonization.

A high rate of nosocomial pneumonia exists among intubated patients receiving mechanical ventilation. Retrograde colonization of the oropharynx and trachea with bacteria from the stomach is not widely appreciated in the pathogenesis of pneumonia. Gastric colonization is affected by age, malnutrition, antibiotics, disease of the gastrointestinal tract, and changes in pH. The widespread use of antacids and/or histamine type 2 blockers as prophylaxis against stress bleeding in the ventilated patient may also increase gastric pH and the risk of colonization in the upper gastrointestinal tract. Migration of bacteria between the stomach, oropharynx and trachea in the intubated patient may be a dynamic system involving large numbers of bacteria. The high fatality rate of mechanically ventilated patients with pneumonia, which persists despite treatment of these patients with appropriate antimicrobial therapy, underscores the need for effective measures of prevention. Preventive measures include the appropriate use of antibiotics, proper decontamination of respiratory therapy equipment, the cautious use of drugs that alter the natural gastric acid barrier, or, possibly, the selective use of antibiotics to prevent or reduce gastric, oropharyngeal and tracheal colonization.

Cross Infection↗

Survey of AIDS knowledge and behavior changes among Massachusetts adults.

In October 1987, 1,323 Massachusetts residents were randomly interviewed by telephone to explore their exposure to AIDS educational efforts, levels of knowledge about AIDS, and whether that knowledge modified their behavior. Gay/bisexual males, iv drug users and heterosexual respondents were compared as were blacks, Hispanics, and whites. While 81% of respondents had read or heard mass media stories about AIDS, in the previous week, only 5% had ever been counseled about AIDS by a physician. Over 97% of black (N = 152) and white respondents (N = 1,057), as well as gay/bisexual males (N = 21) and iv drug users (N = 33) were aware that HIV can be transmitted by homosexual or heterosexual intercourse and by sharing needles when injecting drugs. However, 9% of the 55 Hispanics interviewed were unaware of male homosexual transmission, and 7% did not know about heterosexual transmission or the risks of needle sharing. Twenty percent of Hispanics, compared with 9% of other respondents, did not know HIV can be transmitted sexually by someone who appears healthy. Fifty-two percent of gay/bisexual males, 27% of iv drug users, and 21% of those who had multiple heterosexual partners in recent years reported adopting abstinence, monogamous relations, or condom use to avoid HIV exposure. Those who continued risky behavior were just as knowledgeable about HIV transmission, but they were less likely to report that they worry a great deal about getting AIDS, 14% vs 32%. The results indicate that new strategies and resources are needed to educate Hispanics. Physicians need to counsel more persons about HIV transmission and further efforts are needed to translate knowledge about HIV transmission into behavior change to avoid the virus.

Acquired Immunodeficiency Syndrome↗

Nosocomial pneumonia in the ICU patient.

Although mechanically ventilated patients represent only a small proportion of the hospital population at risk for pneumonia, they are generally seriously ill with disproportionately high rates of pneumonia and fatality. Hand carriage of nosocomial pathogens is a well-known mode of transmission and can be substantially reduced by proper handwashing. Knowledge of the potential hazards of all respiratory therapy equipment and tubing condensate is essential in preventing transmission of nosocomial pathogens that are often implicated in hospital-acquired pneumonia in ventilated patients. Administration of prophylactic antibiotics may reduce the risk of pneumonia, but more studies are needed in this area. Over the past decade there has been significant progress in the prevention of nosocomial pneumonia, but more research is needed to firmly establish the efficacy of these concepts in specific subsets of hospitalized patients.

Bacterial Infections↗

Nosocomial pneumonia in the intubated patient. New concepts on pathogenesis and prevention.

Mechanically ventilated patients have disproportionately high rates of pneumonia compared with nonintubated patients. The presence of an endotracheal tube circumvents natural host defenses, causes local trauma and inflammation, and increases the risk for aspiration of nosocomial pathogens from the oropharynx. Due to the high fatality rate of nosocomial pneumonia and the poor outcomes despite the use of appropriate antibiotic therapy, efforts have been directed at the prevention of infection. Efforts have included the discrete use of antibiotics, compliance with standard infection control techniques, a knowledge of the risks associated with respiratory therapy equipment, proper patient positioning to reduce the chance of gastric reflux, reduction of gastric overgrowth with bacteria, and in some patients, local antibiotics to reduce colonization in the oropharynx and gastrointestinal tract. Sir William Osler called pneumonia "the Captain of the men of death." Although progress has been made to reduce the rank from Captain, greater efforts are needed to improve our understanding of pathogenesis, prevention, diagnosis, and treatment of this infection.

Cross Infection↗

Nosocomial infection in adult patients with sickle cell anemia.

Although the vulnerability of patients with sickle cell disease to infection with encapsulated organisms is well recognized, nosocomial transmission of infection has not been studied in this population. We describe eight serious, nosocomially transmitted infections in four adult patients hospitalized for complications of sickle cell disease, which led to death in one patient and prolonged hospital stays in three others. Although we have not surveyed all patients with sickle cell disease for rates of nosocomial infection, the cases presented suggest that these patients may be at increased risk. Risk can be reduced if health care workers are especially vigilant in adhering to handwashing and other infection control measures when caring for these patients. Additionally, we recommend that a patient with sickle cell disease not share a room with a patient known to have or suspected of having a nosocomial or community-acquired infectious disease.

Adult↗

Human immunodeficiency virus (HIV) infection of the uterine cervix.

Human immunodeficiency virus (HIV) has been detected in cervical secretions from HIV-infected women. We report the isolation of HIV from four cervical biopsy specimens. Cervicitis was shown by immunohistochemical staining in cervical biopsy specimens from four HIV-seropositive women; cervicitis was not found in cervical biopsy specimens from four HIV-seronegative women. We found HIV antigens in monocyte-macrophages and endothelial cells within the submucosa of three of these cervices by specific immunohistochemical staining. Small numbers of HIV-infected cells resembling lymphocytes also were found in the cervical mucosa. The virus was not shown by culture or immunohistochemistry in cervical biopsy specimens from the four HIV-seronegative women. These findings suggest that HIV enters cervical secretions from selected infected cell populations within the cervical tissue. The HIV-infected cells in cervical tissue may be involved in transmission of HIV by heterosexual contact and to neonates born to HIV-infected women.

Adult↗

Nosocomial infection and fatality in medical and surgical intensive care unit patients.

We prospectively studied 526 patients admitted to the medical intensive care unit (MICU) and 799 patients admitted to the surgical intensive care unit (SICU) at a municipal hospital over a 20-month period. Rates of nosocomial infection were higher in the SICU patients (31% vs 24%). The SICU patients had more urinary tract infections, bacteremias, and wound infections, and the MICU patients were older, had higher acute physiology scores on admission and were more often admitted with shock or coma. The SICU patients were more likely to have received prior antibiotic therapy and had significantly higher numbers of endotracheal tubes, arterial lines, central venous lines, and indwelling bladder catheters. Of the 23 variables univariately associated with nosocomial infection, only five remained significant after entry into step-wise regression models. The MICU patients had a higher fatality rate in the MICU than did the SICU patients (18% vs 10%), but the relative risk of a death following nosocomial infection was 3.5 for both groups. Thirty variables were significantly associated with hospital fatality; nine remained significant after analysis by stepwise logistic regression.

Aged↗

Nosocomial pneumonia in intubated patients given sucralfate as compared with antacids or histamine type 2 blockers. The role of gastric colonization.

Gram-negative nosocomial pneumonia may result from retrograde colonization of the pharynx from the stomach, and this may be more likely when the gastric pH is relatively high. We studied the rate of nosocomial pneumonia among 130 patients given mechanical ventilation in an intensive care unit who were receiving as prophylaxis for stress ulcer either sucralfate (n = 61), which does not raise gastric pH, or conventional treatment with antacids, histamine type 2 (H2) blockers, or both (n = 69). At the time of randomization to treatment, the two groups were similar in age, underlying diseases, and severity of acute illness. Patients in the sucralfate group had a higher proportion of gastric aspirates with a pH less than or equal to 4 (P less than 0.001) and significantly lower concentrations of gram-negative bacilli (P less than 0.05) in gastric aspirates, pharyngeal swabs, and tracheal aspirates than did patients in the antacid-H2-blocker group. The rate of pneumonia was twice as high in the antacid-H2 group as in the sucralfate group (95 percent confidence interval, 0.89 to 4.58; P = 0.11). Gram-negative bacilli were isolated more frequently from the tracheal aspirates of patients with pneumonia who were receiving antacids or H2 blockers. Mortality rates were 1.6 times higher in the antacid-H2 group than in the sucralfate group (95 percent confidence interval, 0.99 to 2.50; P = 0.07). Although our results fell just short of statistical significance when they were analyzed according to intention to treat, they suggest that agents that elevate gastric pH increase the risk of nosocomial pneumonia in patients receiving ventilation by favoring gastric colonization with gram-negative bacilli. We conclude that in patients receiving mechanical ventilation, the use of a prophylactic agent against stress-ulcer bleeding that preserves the natural gastric acid barrier against bacterial overgrowth may be preferable to antacids and H2 blockers.

Antacids↗