Pseudomonas aeruginosa: growth in distilled water from hospitals.

Pseudomonas aeruginosa can grow relatively fast in distilled water obtained in hospitals and achieve high cell contaminations which remain stable for long periods of time. Cells grown in distilled water react quite differently to chemical and physical stresses than cells grown in standard laboratory culture media.

An outbreak of hepatitis B associated with jet injections in a weight reduction clinic.

From January 1984 through November 1985, 31 clinical cases of hepatitis B occurred among attendees of a weight reduction clinic (clinic 1). Before the onset of illness, each case-patient had received a series of injections of human chorionic gonadotropin administered by jet injectors at clinic 1. Clinical history, risk factor assessment, serologic evaluation, and review of clinic injection records were obtained on 287 (84%) of 341 persons who had attended clinic 1 in the first 6 months of 1985. Of this cohort, 21% (60/287) had evidence of acute infection with hepatitis B virus (either documented clinical cases or antibody to hepatitis B core antigen, IgM positive). Of persons who had been given human chorionic gonadotropin at the clinic during the period studied, 24% (57/239) of those receiving human chorionic gonadotropin only by jet injector experienced acute hepatitis B virus infection. None of the 22 persons who had received injections only by syringe experienced hepatitis B virus infection. Stopping the use of the jet injectors on July 2, 1985, at clinic 1, was associated with the termination of this outbreak. This investigation demonstrated that jet injectors can become contaminated with hepatitis B virus and then may be vehicles for its transmission.

Campylobacter fetus infections in children.

There has been a gradual accumulation of reported Campylobacter fetus human infections since the first description in 1947. The taxonomy of these fastidious and morphologically confusing organisms has been recently revised and, in the past few years, through the use of selective culture medium for stool isolation C fetus has been implicated as a frequent paghogen in children. There are three relatively distinct patterns of human C fetus infection. The first, most frequent, pattern of disease is enteritis which is usually uncomplicated and due to C fetus subsp jejuni. A second form of disease consists of focal infections, often associated with vasculitis and/or chronic bacteremia. These infections, due to C fetus subsp intestinalis, are seen most often in older, debilitated, or chronically ill men. The third pattern, perinatal infections causing abortion, prematurity, and neonatal meningitis, is the least frequent, but these infections are usually fetal to the fetus or infant and are also due to C fetus subsp intestinalis.

Decontaminated single-use devices: an oxymoron that may be placing patients at risk for cross-contamination.

OBJECTIVE: To determine whether reprocessed single-use devices would meet regulatory standards for sterility and meet the same materials standards as a new device. DESIGN: The study included single-use and reusable biopsy forceps and papillotomes and a reusable stone retrieval basket. The suitability of these devices for cleaning and disinfection or sterilization was examined. METHODS: Testing of cleanability was conducted on devices contaminated with technetium 99-radiolabeled human blood. Instruments were cleaned using hospital recommended practices for manual cleaning. Gamma counts per second were determined before and after cleaning to localize contaminants, which were additionally visualized using light and scanning electron microscopy. X-ray photoelectron spectroscopy was used to quantify contamination elements on the materials tested. Residual bioburden testing on instruments contaminated with microorganisms suspended in coagulable sheep blood was carried out to establish the efficacy of disinfection and sterilization. RESULTS: All devices remained contaminated after cleaning, but single-use devices and the stone basket tended to be more heavily contaminated than reusable forceps and papillotomes. Cleaning procedures facilitated distribution of contaminants further into the lumens of the disposable forceps. Decreased concentrations of silicon and increased concentrations of carbon and nitrogen suggested that layers of silicon lubricant had been removed and contaminants were organic material. Reusable devices were effectively disinfected, but single-use devices were not. Sterilization could not eliminate the challenge microorganisms completely. CONCLUSIONS: None of the reprocessed single-use instruments were effectively cleaned, disinfected, or sterilized. This condition may provide an opportunity for the viability of nonresistant or nosocomial organisms and viruses. Additionally, reprocessing procedures may result in material destruction of fragile devices. Cost-saving initiatives that have inspired reprocessing of single-use devices, despite the absence of data establishing the efficacy of decontamination and the durability of materials throughout reprocessing, should be pushed into the background.

Susceptibility of vancomycin-resistant enterococci to environmental disinfectants.

OBJECTIVE: To determine the susceptibilities of vancomycin-resistant and -sensitive enterococci (VRE and VSE) to various concentrations of commonly used, commercial, hospital-grade disinfectants. DESIGN: A microbial suspension test using inocula of 10(8) cells per mL in a disinfectant test dilution was used to determine inactivation kinetics of the test strains. In each test, 1-mL aliquots were removed from the cell-disinfectant mixtures at 15 and 30 seconds and then at 1-minute intervals for 5 minutes and neutralized. Appropriate serial dilutions were plated on agar medium for enumeration of survivors. RESULTS: VRE and VSE challenge inocula (in the absence of any additional protein or serum challenge) were below the limit of detection (5 colony-forming units/mL) after 15 seconds' exposure to the manufacturers' suggested use-dilutions of quaternary ammonium, phenolic, or iodophor germicidal detergents. In subsequent tests, when the disinfectants were diluted far beyond-the recommended use-dilutions (extended dilution), no differences were demonstrated between the susceptibilities of VRE and VSE. CONCLUSIONS: VRE and VSE are sensitive to a spectrum of commonly used environmental disinfectants and have parallel inactivation rates when challenged with extended dilutions of these products. Our findings did not demonstrate a relationship between antibiotic and germicide resistance. Routine disinfection and housekeeping protocols presently used in hospitals need not be altered due to concerns about the potential for environmentally mediated transmission of antibiotic-resistant microorganisms.

Investigations of intrinsic Pseudomonas cepacia contamination in commercially manufactured povidone-iodine.

OBJECTIVE: Laboratory investigations were initiated with a povidone-iodine antiseptic solution that was intrinsically contaminated with Pseudomonas cepacia. These investigations were helpful in understanding the microbicidal and chemical properties of iodophor solutions and the mechanism by which P cepacia can survive in iodine-containing antiseptics. DESIGN: Included in these studies were: prolonged survival of P cepacia; available and free iodine determinations; microbial challenge studies; and scanning electron microscopic examination of contaminated antiseptic. RESULTS: P cepacia survived in this iodophor antiseptic up to 68 weeks from the date of manufacture. A uniform concentration of 1% available iodine was found in all lots of povidone-iodine tested as specified on the product label, but free iodine (I2) values varied greatly. Low free iodine levels of 0.23 to 0.46 ppm were associated with the contaminated lot of povidone-iodine. Solutions of povidone-iodine with varying levels of free iodine were rapidly microbicidal when challenged with cells of P cepacia derived from culture broth and washed or adapted to growth in water. P cepacia cells taken directly from contaminated povidone-iodine survived for significantly longer periods of time. Large numbers of P cepacia were found embedded in extracellular material and among strands of glycocalyx between cells as shown by scanning electron microscopy. CONCLUSIONS: The physical thickness of cellular and extracellular material that forms on surfaces could protect embedded organisms from the microbicidal action of disinfectants and antiseptics and subsequently allow for extended microbial survival times. Manufacturers should be aware that distribution piping surfaces colonized with bacteria may be a source of product contamination and resistant organisms.

Sanitary care and maintenance of ice-storage chests and ice-making machines in health care facilities.

In response to a reported hospital outbreak traced to the use of contaminated ice in 1968, the Centers for Disease Control and Prevention (CDC) developed an advisory regarding the sanitary care and maintenance of ice-storage chests and ice-making machines. CDC has revised this unpublished advisory several times during the years to respond to requests for guidance from infection control professionals. Because CDC continues to receive inquiries about this topic from infection control professionals, this advisory is being published.

DNA: DNA hybridization method for the diagnosis of hepatitis B infection.

Hepatitis B viral (HBV) DNA was detected in a hepatoma cell line which produces hepatitis B surface antigen (HBsAg) and in patients with acute hepatitis B. The serum of one patient with acute hepatitis B was found to be infectious when injected i.v. into a chimpanzee up to a dilution of 10(-8). Hepatitis B surface antigen (HBsAg) and hepatitis B e antigen (HBeAg) were detectable in the same serum sample by radioimmunoassay up to a dilution of 10(-5) and of 10(-3), respectively. Using DNA: DNA hybridization on nitrocellulose membranes, HBV DNA sequences were detectable up to 10(-8) dilution corresponding to the infectivity level. Based on this finding, it appears that DNA: DNA hybridization is the most sensitive method for detecting hepatitis B virus (HBV) infection. In situations with low virus levels it may be the only indicator of the presence of infectious hepatitis B virus. The use of a tritium-labelled probe makes the method economical and adaptable to hospital laboratories.

Overview of infection control problems: principles in gastrointestinal endoscopy.

The practice of flexible gastrointestinal endoscopy has matured significantly in recent years. Unfortunately, two long-standing problems still exist: the complex physical nature inherent to the endoscopes and accessories, and user compliance with established reprocessing guidelines. Improvements have been made, but newer instruments remain comparatively fragile, expensive, and physically complex, and validated data on reprocessing specific instruments is generally lacking. The practice of flexible gastrointestinal endoscopy today, however, is demonstrably safe and beneficial, provided established practice procedures for reprocessing, with emphasis on instrument cleaning, are followed meticulously in each endoscopy center.

Air sampling for hepatitis B surface antigen in a dental operatory.

Forty samples of air with a mean sample volume of 104 liters were collected during the treatment of patients whose blood was positive for HBsAG: no samples contained HBsAG and occult blood. These findings suggest that, if environmentally mediated transmission of hepatitis B occurs in the dental operatory, it is more likely to occur through contact with contaminated surfaces than through the airborne route.

Practical infection control in oral health surveys and screenings.

Examinations for oral health surveys and screenings are performed by dentists or dental hygienists in a variety of settings. To date, CDC has made no recommendations for infection control specifically for these brief examinations. General principles for infection control can be applied during oral health surveys and screenings.

Thermal profile of a Bacillus species (ATCC 27380) extremely resistant to dry heat.

Spores of Bacillus sp. ATCC 27380 were exposed at intervals to dry-heat temperatures ranging from 125 to 150 C. D-values from 139 to 2.5 h were obtained.

Microbiological evaluation of the vacuum probe surface sampler.

The development of the vacuum probe, a new device for surface sampling, was recently reported. The original technique was slightly modified and a microbiological evaluation was conducted. The probe proved to be an effective sampling device, removing 98% and recovering 88% of surface contaminants resulting from the accumulation of airborne microorganisms. The probe was decidedly less effective in removing and recovering handling contamination than fallout contamination. There was also evidence that certain microorganisms could not survive prolonged exposure to airflow in the probe. However, the vacuum probe procedure recovered twice as many microorganisms as did the swab-rinse technique when compared directly.

Viral hepatitis B: aspects of environmental control.

In recent years it has become increasingly evident that viral hepatitis type B is a major disease problem among patients and/or health professionals associated with environments such as hemodialysis centers, dental operatories, clinical laboratories, and institutions for the mentally retarded. Studies have incriminated the intramural environment as well as specialized equipment and procedures as important factors in disease transmission. With hepatitis B surface antigen (HBsAg) as a marker of potentially infectious blood or body fluids such as saliva, it is possible to assess the environmental role in transmission of hepatitis B by use of a swab-rinse technique coupled with radioimmune assay. Assay procedures have been developed and utilized for detecting HBsAg on surfaces and in air and for quantitating of HBsAg in thermal and chemical inactivation studies. Specific decontamination strategies and recommendations for sterilization or disinfection procedures are described.

Bacillus sp. ATCC 27380: a spore with extreme resistance to dry heat.

An unusual mesophilic Bacillus sp. was isolated from heated soil, and a cleaned spore preparation showed extraordinary resistance to dry heat (D(125C) = 139 h) and relative sensitivity to moist heat (D(80C) = 61 min). Biochemical tests and morphology fit no described species.