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Biomedical subjects

A A Harris

Publications and source records attributed to A A Harris.

At least 37 records · Page 2Linked to original sources
PubMed1987

A pseudoepidemic due to atypical mycobacteria in a hospital water supply.

We describe a pseudoepidemic due to atypical mycobacteria contaminating the water used by a pathology laboratory and bronchoscopy suite on two floors of the same hospital building. Inspection of laboratory procedures revealed that contamination occurred during specimen processing in pathology and while obtaining the bronchoscopic specimens. Mycobacterium gordonae, Mycobacterium avium complex, and Mycobacterium scrofulaceum were identified. During an eight-month period, a total of 22 (31%) of 70 patients with positive acid-fast smears had either an illness inconsistent with tuberculosis or a known alternate diagnosis. Control was easily obtained by insertion of a 0.2-micron polymer filter into the outflow tubing of our pathology tap water-deionizing unit and the tap water source in the bronchoscopy suite. The pseudoepidemic led to additional diagnostic-therapeutic intervention, but no patient experienced delay in appropriate diagnosis. Pseudoepidemics due to atypical mycobacteria will likely be of increased importance in institutions providing care to patients with acquired immunodeficiency syndrome.

Disease Outbreaks↗
PubMed1987

Nosocomial Legionnaires' disease.

Members of the family Legionellaceae have emerged as important nosocomial pathogens. Bronchopneumonia is the typical illness and mimics other nosocomial pneumonias. On rare occasion, surgical wound infections may be due to legionellae. Legionella pneumophila is the species causing most human illness, but other species may predominate in individual institutions. Pneumonia is acquired by inhalation of environmental aerosols from water sources contaminated by Legionella sp. In the hospital setting contaminated water sources include potable water, heat-exchange systems, and cooling towers. Water temperature control and maintenance programs may prevent colonization of water systems. Should clinical cases and water colonization occur, aggressive suppression/eradication programs--by chlorination or heat/flush--must be instituted. Surveillance of pneumonias in high-risk patient groups is essential for early detection of a nosocomial outbreak. There has been no evidence of person-to-person transmission. Familiarity with diagnostic techniques and their pitfalls will permit institution of effective antimicrobial therapy.

Cross Infection↗
PubMed1986

Acute neurologic infections.

This article discusses acute bacterial, viral, toxin-mediated, and parasitic neurologic infections, emphasizing those infections that are potentially treatable, are rapidly fatal if untreated, or pose a significant risk of person-to-person transmission.

Bacterial Infections↗
PubMed1986

Haemophilus influenzae meningitis in the presence of a cerebrospinal fluid shunt.

Haemophilus influenzae meningitis in the presence of a cerebrospinal fluid shunt has been reported uncommonly. Staphylococcus aureus and Staphylococcus epidermidis, the most common etiological agents, are usually acquired by contiguous spread from an intraoperative or perioperative source. These infections usually occur within 2 months of shunt insertion and are rarely associated with bacteremia. Review of the literature shows that infection with H. influenzae typically occurs later than with the more common pathogens, is commonly associated with bacteremia, and frequently can be treated with antibiotics alone.

Adolescent↗
PubMed1985

Results of a screening method used in a 12-month stool survey for Escherichia coli O157:H7.

Escherichia coli serotype O157:H7 has been epidemiologically linked to outbreaks of hemorrhagic colitis associated with fast-food restaurants and nursing homes. Sporadic cases now exceed those associated with outbreaks. The incidence of the organism in patients with common diarrhea syndromes and in asymptomatic persons is unknown. Routine serotyping of E. coli isolates is impractical for most clinical microbiology laboratories. We developed a screening plate by utilizing sorbitol fermentation as a biochemical marker to identify organisms for serotyping. A total of 2,552 stool samples were screened. In 106 (4.1%), sorbitol-negative E. coli were identified. Of these, two were serotype O157:H7, and both produced a Vero cell toxin. One patient had hemorrhagic colitis and the other a mild, febrile, self-limited diarrhea with no other bacterial pathogen identified. This plate provides an easy, effective method of screening for sorbitol-negative E. coli, a process facilitating the selection of organisms for serotyping and one that may help clarify this organism's role in human disease.

Canada↗
PubMed1985

A urine preservative system to maintain bacterial counts. A laboratory and clinical evaluation.

The urinary tract is a common site of infection in the hospitalized, institutionalized, or ambulatory patient population. Ideally, urine should be cultured immediately or refrigerated up to 24 hours for quantitative examination for microorganisms. In the evaluation of patients at their homes or in long-term care facilities, rapid plating or refrigeration may not be practical. This is also true when evaluating small children in whom external collection devices are required to obtain a specimen. Because of these limitations, we evaluated a urine preservative and transport system, the Sage Products Urine Culture Tube, in a study of 1469 clinical specimens. This tube utilizes boric acid (1.1% final concentration) as a preservative. The Urine Culture Tube was easy to use and was as effective as refrigeration in maintaining bacterial counts. This system may be particularly useful where rapid transport or refrigeration is limited.

Bacteria↗
PubMed1985

Antibodies to hepatitis B surface antigen as the sole hepatitis B marker in hospital personnel.

The epidemiologic and serologic differences between hospital employees with antibodies to hepatitis B surface antigen (anti-HBs) alone or in combination with antibodies to hepatitis B core antigen (anti-HBc) were evaluated. Of 105 employees with anti-HBs, 38 (36%) did not have anti-HBc. Sera from employees with anti-HBs alone had significantly lower mean sample ratio units of anti-HBs than sera with both antibodies (15.9 +/- 43.2 as compared to 110.3 +/- 73.9, p less than 0.0005) and more commonly had less than 10 sample ratio units of anti-HBs (32 [84%] of 38 as compared to 9 [13%] of 67, p = 0.0001). The anti-HBs in sera with anti-HBs alone was predominantly IgM as shown by inactivation with 2-mercaptoethanol and the presence of anti-HBs activity in serum IgM fractions. Failure of protection from hepatitis B virus infection in persons with anti-HBs alone and the presence of nonprotective IgM anti-HBs in chimpanzees has been reported. Our data suggest the use of anti-HBs as a single serologic screening test for hepatitis B virus immunization programs may not be reliable in identifying employees with protective antibodies.

Chicago↗
PubMed1984

Selected aspects of nosocomial infections in the 1980s.

Unusual or rare pathogens and syndromes may become significant problems in nosocomial infection. Pathogens that usually produce community-onset disease, particularly respiratory viruses, Legionella, and atypical mycobacteria, also cause nosocomial infection. Conversely, nosocomial pathogens may also produce disease in the community, as has been seen with Clostridium difficile. Contamination of parenteral and antiseptic solutions continues to be a problem in hospitals. Hospital-acquired viral infections are receiving increasing recognition. Nosocomial gastrointestinal infections, although of low frequency, are of major import because of their epidemic potential. Airborne transmission of pathogens is becoming more apparent at the same time that recognition of the importance of hand transmission creates hope for infection control. Antibiotics influence the type of microorganisms that colonize patients, but the host determines superinfection.

Air Microbiology↗