Disinfection of respirator tubing: a comparison of chemical versus hot water machine-assisted processing.

A comparison of machine-assisted chemical disinfection, using a glutaraldehyde solution, and machine-assisted hot water disinfection was made by placing a large inoculum (approximately 10(7) colonies of Pseudomonas aeruginosa or Acinetobacter calcoaceticus var. anitratus) in sets of tubing before processing. Machine-assisted chemical processing proved to be the most efficient method with a disinfection failure rate of 6 per cent (two positive tubes out of 35). Machine-assisted hot water processing had a disinfection failure rate of 83 per cent (44 of 53 tubes were not successfully disinfected). Some of the tubes that were disinfection failures were dried in a hot air cabinet after the initial sampling, which further reduced the colony counts in the tubing but did not totally eliminate growth except in one tube. The colony counts after drying, showed that A. anitratus was 15 per cent more sensitive to hot air drying than Ps. aeruginosa, but this was not a statistically significant reduction.

Comparison of blood cultures obtained simultaneously by venepuncture and from vascular lines.

This study was designed to compare blood cultures drawn simultaneously from a pulmonary artery line or arterial line (line) and a peripheral site by venepuncture (VP). Two or three cultures were obtained by VP and from a line during each febrile episode in 79 patients. Line blood cultures were falsely negative in 1.3% of cultures and VP blood cultures were falsely negative in 2.0%. Three point eight per cent of blood cultures drawn from lines were falsely positive (contaminated), and 1.7% of VP cultures were falsely positive. No significant correlation was found between falsely positive line cultures and a positive three-way tap culture, line in use for 4 days or more, insertion of line during an emergency. We recommend that in the critically ill patient an arterial or pulmonary artery line may be used for obtaining reliable cultures.

Symposium on infections in the compromised host: The extremities of age: the newborn and the elderly.

The newborn and the elderly are at increased risk for infection because their immune defenses are suppressed as a result of age and institutionalization. The elderly person has the additional likelihood that chronic illness and debility will lead to infection, whereas the newborn has an increased chance of exposure to infectious agents from the mother and the environment.

Nursing measures for the prevention of infection in the compromised host.

Deficits in the external and internal defense mechanisms place immune-suppressed patients at great risk of acquiring deficit-specific infections. This article will acquaint nurses, patients, and their families with the many measures that are available to them to prevent such infections and the mortality associated with them. Many of these measures can prolong the time available to patients to receive treatment that may arrest or reverse the underlying disease processes.

Caring for the infectious patient: risk factors during pregnancy.

Health care personnel are exposed to infectious diseases in the community as well as in the health care setting when they care for patients with transmissible conditions. Pregnant nurses, physicians and others face an additional risk--that of exposing their unborn children to some of these infections. Risk factors vary greatly between diseases and it is, therefore, important that each be evaluated and acted upon realistically. We will discuss and compare the risk of infections such as hepatitis, cytomegalovirus, tuberculosis, chickenpox, and others. With this knowledge, administrators and personnel involved will be able to make decisions about which patients should not be cared for by pregnant personnel, and which areas pose too high a risk for the mother and child so that a temporary transfer may be advisable. We address the multiplicity of preventive measures available for the prevention of maternal infections.

Cost-effective utilization of microbiology data.

A significant number of bacterial cultures are ordered by health care professionals each day, yet the actual utilization of culture results, either for determining specific diagnoses or for targeting antimicrobial therapy, is much lower than would be anticipated. A multifactorial study was conducted to determine the rate of "appropriate" usage of culture results in a community teaching hospital. The effect of several variables on culture utilization was analyzed, including: initiator of the request for culture (physician or nurse); hospital service requesting the culture; and culture site. Utilization of results differed considerably within all three variables, yet the general conclusion could be drawn that cost-effectiveness would be significantly improved if hospital personnel gave careful consideration to the need for microbiologic cultures before they request them.

Three clusters of Bacillus pseudobacteremia related to a radiometric blood culture analyzer.

During a ten-month period from September 1981 to July 1982 three episodes of pseudobacteremia due to Bacillus species occurred at this 550-bed institution. The first involved eight isolates, the second 11, and the third seven isolates of the organism, all with the same antibiogram. The patients involved did not exhibit clinical signs of septicemia, and in only one case was more than one specimen per patient positive when multiple blood samples were obtained. Occasional blood cultures of Bacillus species identified in between clusters revealed a different antibiogram. Extensive epidemiologic investigation of patient locations, phlebotomists, and time of cultures yielded no common source. Components involved in the transport and processing of blood cultures, including the radiometric blood culture processor, were also sampled but without recovery of the organism. After the last episode, a layer of dust was noted inside the machine, and culture of this dust grew Bacillus spp. with the same antibiogram as those found in the blood cultures. The filter from an air conditioning unit in close proximity to the machine grew several species of Bacillus. It is presumed that Bacillus spores in the dust were introduced into the blood culture bottles following the heat sterilization of the gas sampling (inoculation/removal) needles. Modification of the cover of the machine was undertaken to prevent access of dust bearing microbes to the inside of the machine. In addition, maintenance now includes regular disinfection/cleaning of the "floor" of the machine, and more frequent changes of the air conditioner filter.