The disposition and pharmacokinetics in humans of 5-azacytidine administered intravenously as a bolus or by continuous infusion.

The disposition of 5-[4-14C]azacytidine, administered i.v. as a bolus or continuous infusion, was studied in cancer patients. After bolus, plasma 14C levels exhibited as multiphasic disappearance pattern; half-life (t1/2, beta phase) = 3.4 to 6.2 hr. Of 14C in plasma, less than 2% was associated with 5-[4-14C]azacytidine 30 min after dose. The ratios of 14C levels were: red cells/plasma, approximately 0.8; leukocytes/plasma, 1.1 to 2.3; nucleic acids/leukocytes, 0.2 to 0.43; sputum/plasma, 0.05 to 0.17. Urinary excretion (3 days) accounted for 73 to 98% of 14C, LEss than 1% in feces. The relative concentration of 5-azacytidine in plasma with continuous infusion stayed higher than with bolus; urinary excretion was similar. Fewer side effects were observed with continuous infusion than with bolus. The stability of 5-azacytidine was determined in various media at several temperatures by thin layer chromatography and nuclear magnetic resonance. At 20 degrees in Ringer's lactate (pH 6.2), the t1/2 was 94 to 100 hr. Stability increased with lowering of temperature and pH. From our data we conclude that 5-azacytidine should be given by continuous infusion rather than as a bolus.

HIV infection and primary resistance to antituberculosis drugs in Abidjan, Côte d'Ivoire.

OBJECTIVE: To determine the prevalence of Mycobacterium tuberculosis resistance to antituberculosis drugs, and to relate this resistance to HIV serologic status. DESIGN: Cross-sectional prevalence study. SETTING: The two major outpatient tuberculosis clinics in Abidjan, Côte d'Ivoire, West Africa. PATIENTS: Sixty individuals with newly diagnosed pulmonary tuberculosis and sputum smears positive for acid-fast bacilli. MAIN OUTCOME MEASURES: HIV serologic status and in vitro testing for susceptibility of M. tuberculosis isolates to antituberculosis drugs. RESULTS: M. tuberculosis was isolated from 82% (49 out of 60) of sputum specimens. Thirty-five per cent (17 out of 49) were obtained from HIV-seropositive and 65% (32 out of 49) from HIV-seronegative patients. There was no statistically significant difference in the proportion of resistant isolates from HIV-seropositive versus HIV-seronegative patients, although the relatively small sample size limited power. Of the total number of isolates, 17% were resistant to isoniazid; resistance was less to streptomycin (7%), rifampin (2%), pyrazinamide (0%), and ethambutol (0%). Eighteen and 21% of mycobacterial isolates from HIV-seropositive and HIV-seronegative individuals, respectively, were resistant to one or more of these drugs. CONCLUSIONS: Surveys of this type are useful in planning and evaluating tuberculosis preventive therapy in individuals with dual infection.

Theoretical calculations of relative ion yields for glow discharge mass spectrometry.

Quantitative determination of the elemental composition of metals and other solids by glow discharge mass spectrometry requires a calibration factor for each element. In past work, these factors, called relative ion yields (RIYs), have been determined experimentally from the mass spectra of standards of certified composition. The RlYs of some elements were found to be over 10 times larger than the RIYs of other elements. In this study a simple calculation of the RIYs of the elements within the same sample is derived from a theoretical framework which takes into account the combined effects of sputtering and ionization. The ionization function involves the electron affinity and the first ionization potential of each element, plus two unknown parameters. By favorable selection of a temperature parameter and a chemical-potential parameter, the RIYs calculated by this method were found to agree satisfactorily with the experimental RlYs of former work. The temperature of 16,000 K (used in this work) corresponds to an average electron energy of ∼ 2 eV.

Relative ion yields measured with a high-resolution glow discharge mass spectrometer operated with an argon/hydrogen mixture.

Quantitative elemental analysis by glow discharge mass spectrometry (GDMS) requires a calibration factor for each element. The calibration factors used in the present work are called relative ion yields (RIYs). The RIYs of each of 19 elements within samples of four National Institute of Standards and Technology steel reference materials (nos. 661-664) were measured using pure argon and an argon mixture containing 1.0% hydrogen by volume. The RIYs measured using pure argon correlated within a factor of approximately 2-3 to the RIYs calculated by a theoretical model. The RlYs measured for these 19 elements using the argon mixture containing 1.0% hydrogen correlated within a factor of approximately 1.3 to the calculated RIYs. These results may have significant analytical potential with respect to GDMS and may have application to other plasma techniques.

A nosocomial pseudo-outbreak of Mycobacterium xenopi due to a contaminated potable water supply: lessons in prevention.

OBJECTIVES: To determine risk factors for Mycobacterium xenopi isolation in patients following a pseudo-outbreak of infection with the organism. DESIGN: Retrospective cohort analysis of mycobacteriology laboratory specimen records and frequency-matched case-control study of hospital patients. SETTING: General community hospital. PATIENTS: For the case-control study, 13 case patients and 39 randomly selected controls with mycobacterial cultures negative for M xenopi, frequency matched by specimen source, whose specimens were submitted from June 1990 through June 1991. RESULTS: Between June 1990 and June 1991, M xenopi was isolated from 13 clinical specimens processed at a midwestern hospital, including sputum (n = 6), bronchial washings (2), urine (4), and stool (1). None of the patients with M xenopi-positive specimens had apparent mycobacterial disease, although five received antituberculosis drug therapy for a range of one to six months. Specimens collected in a nonsterile manner were more likely to grow the organism than those collected aseptically (3.1% versus 0, relative risk = infinity, P = 0.003). M xenopi isolation was attributed to exposure of clinical specimens to tap water, including rinsing of bronchoscopes with tap water after disinfection, irrigation with tap water during colonoscopy, gargling with tap water before sputum collection, and collecting urine in recently rinsed bedpans. M xenopi was isolated from tap water in 20 of 24 patient rooms tested, the endoscopy suite, and the central hot water mixing tank, but not from water in the microbiology laboratory. The pseudo-outbreak occurred following a decrease in the hot water temperature from 130 degrees F to 120 degrees F in 1989. CONCLUSIONS: Maintenance of a higher water temperature and improved specimen collection protocols and instrument disinfection procedures probably would have prevented this pseudo-outbreak.

Pseudo-outbreak of tuberculosis in an acute-care general hospital: epidemiology and clinical implications.

A 10-fold increase in patients with Mycobacterium tuberculosis-positive specimens in one hospital laboratory prompted an investigation. Clinical and epidemiological data, along with M tuberculosis DNA fingerprinting results, indicated that laboratory contamination led to nine false-positive M tuberculosis cultures. Pseudo-infection should be considered in patients with unusual tuberculosis presentations, negative acid-fast bacilli smears, and only one positive culture with a low colony count.

Processes involved in the development of latent fingerprints using the cyanoacrylate fuming method.

Chemical processes involved in the development of latent fingerprints using the cyanoacrylate fuming method have been studied. Two major types of latent prints have been investigated-clean and oily prints. Scanning electron microscopy (SEM) has been used as a tool for determining the morphology of the polymer developed separately on clean and oily prints after cyanoacrylate fuming. A correlation between the chemical composition of an aged latent fingerprint, prior to development, and the quality of a developed fingerprint has been observed in the morphology. The moisture in the print prior to fuming has been found to be more important than the moisture in the air during fuming for the development of a useful latent print. In addition, the amount of time required to develop a high quality latent print has been found to be within 2 min. The cyanoacrylate polymerization process is extremely rapid. When heat is used to accelerate the fuming process, typically a period of 2 min is required to develop the print. The optimum development time depends upon the concentration of cyanoacrylate vapors within the enclosure.

Radiometric method for pyrazinamide susceptibility testing of Mycobacterium tuberculosis in egg-yolk-enriched BACTEC 12A medium.

A radiometric method for testing the susceptibility of Mycobacterium tuberculosis to pyrazinamide in egg-yolk-enriched 12A medium (pH 5.5) is described. We obtained 100% agreement between the 7H10 agar method with 25 microgram of pyrazinamide per ml and the modified radiometric method with a drug concentration of 50 microgram/ml in tests of 90 clinical isolates.

Preparation of acid-fast microscopy smears for proficiency testing and quality control.

A method is presented for preparing smears for proficiency testing and quality control in acid-fast microscopy. The work was prompted by the increased demand for acid-fast bacilli positive smears with characteristic microscopic appearance and among-smear uniformity.

Acid-fast microscopy on polycarbonate membrane filter sputum sediments.

Polycarbonate membrane filters were used to concentrate 916 sputum specimens for detecting acid-fast bacilli by microscopic examination. These results were compared with those of smears prepared from centrifugates and direct smears of the same specimens. Culture isolation, the control procedure, demonstrated the presence of acid-fast bacilli in 76 specimens. The number of positive specimens detected by microscopy was 82 on polycarbonate membrane filter concentrates, with an 80.2% sensitivity; 53 on centrifugate smears, with a 62.2% sensitivity; and 44 on direct smears, with a 55.8% sensitivity. Acid-fast microscopy results demonstrated that the sensitivity of the polycarbonate membrane filter sputum concentration method was superior to that of the recommended centrifuge concentration method and that the former method may be considered a rapid alternative when culture for acid-fast bacilli is impractical.

Use of cetylpyridinium chloride and sodium chloride for the decontamination of sputum specimens that are transported to the laboratory for the isolation of Mycobacterium tuberculosis.

A method is presented for the decontamination, liquefaction, and concentration of sputum specimens that are in transport more than 24 h. The method is inexpensive, and culture results compare well with those obtained with the accepted N-acetyl-L-cysteine and sodium hydroxide method for the isolation of tubercle bacilli. The working solution, 1% cetylpyridinium chloride and 2% sodium chloride, is mixed in equal volumes with sputum before the specimens are shipped. Tubercle bacilli remained viable after 8 days of exposure to this solution. Only Lowenstein-Jensen medium was used because the cetylpyridinium chloride in the inoculum remains active on 7H10 or other agar base media and partially inhibits the growth of tubercle bacilli.

Phenolic acridine orange fluorescent stain for mycobacteria.

A new fluorescence acid-fast staining method with acridine orange as the specific stain is presented. Only two reagents are required: the acridine orange-specific stain and a destaining-counterstaining reagent. Compared with auramine fluorescence acid-fast staining, there was less nonspecific staining of non-acid-fast debris which fluoresced a pale green contrasting color to provide a background in which to search for the red-to-orange fluorescing acid-fast bacilli. The results of the study indicate that the acridine orange method is superior to the auramine method in detecting acid-fast bacilli in specimen smears.

Outbreak of Mycobacterium chelonae infection associated with use of jet injectors.

Between January 1 and May 15, 1988, foot infections due to Mycobacterium chelonae subspecies abscessus were diagnosed in eight persons who had undergone invasive procedures at a podiatry office. A cohort study was performed to evaluate risk factors for disease. Persons who underwent procedures before 10:30 AM were more likely to have developed infection than those with procedures after that time (relative risk, 5.6). In addition, procedures involving any of the second through fourth toes were more likely to have resulted in infection than procedures involving only the first and/or fifth toes (relative risk, 4.4). Persons with 0, 1, or 2 risk factors had attack rates of 5%, 14%, and 60%, respectively. Mycobacterium chelonae subspecies abscessus organisms of the same antimicrobial resistance pattern as the patients' strains were cultured from distilled water in a reusable, nonsterilized container. A jet injector used to administer lidocaine was held between procedures in a mixture of the distilled water and a disinfectant as recommended by the manufacturer. Inoculation of patients with mycobacteria by the jet injector may have only occurred early in the day due to slow killing of the bacteria by the disinfectant. The outbreak emphasizes the pathogenicity of this water-associated organism and the need for high-level disinfection of jet injectors.

Mycobacterium kubicae sp. nov., a slowly growing, scotochromogenic Mycobacterium.

A previously uncharacterized, slowly growing, scotochromogenic Mycobacterium species was detected by HPLC analysis of the cell-wall-bound mycolic acids. The mycolic acid pattern standard was shown to be a late-eluting, contiguous peak cluster occurring at approximately 8-9 min. The mycolic acid pattern was noted to be most similar in number of peaks and range of elution to that reported previously for Mycobacterium asiaticum. However, the relative distribution of peaks within the elution range demonstrated a pattern with prominent peaks that started to emerge later than the characteristic M. asiaticum pattern. Standard biochemical identification test results were similar to those of the photochromogenic species M. asiaticum. Comparative 16S rRNA gene sequence analysis confirmed the genetic uniqueness of the strains and demonstrated the unclassified mycobacteria to be in a unique, intermediate position between slow and rapid growers in the phylogenetic tree of Mycobacterium. The name Mycobacterium kubicae sp. nov. is proposed for this taxon. The type strain is CDC 941078T (= ATCC 700732T = CIP 106428T).

Nosocomial Mycobacterium fortuitum colonization from a contaminated ice machine.

Between October 15 and November 18, 1985, 5 patients on a medical ward of the Albany VA Medical Center (Ward 8A) became colonized with Mycobacterium fortuitum. Because other patients in Ward 8A were at risk of developing disease with M. fortuitum, microbiologic surveillance to identify colonization in sputum was begun. By February 15, 1986, 30 colonized patients had been identified in this ward but none in another ward with a comparable patient population, which suggests a source unique to Ward 8A. Because water has been recognized as a source of opportunistic mycobacterial pathogens, we conducted a retrospective case-control study using a telephone survey questionnaire to examine a number of water exposures in 10 patients and 20 control subjects. Exposure to ice from the Ward 8A ice machine, but not to potable water, was associated with colonization with M. fortuitum. Large-volume water samples from a variety of sources were cultured for acid-fast bacilli. M. fortuitum was isolated only from the ice machine in Ward 8A. The ice machine was disconnected, and no additional patients became colonized. Although ice machines are infrequently implicated in nosocomial outbreaks, they represent a potential source for pathogens that survive or replicate in water.

Mycobacterium celatum sp. nov.

A new slowly growing nonphotochromogenic Mycobacterium species of clinical importance is described. The biochemical characteristics of this organism were similar to those of Mycobacterium xenopi and members of the Mycobacterium avium complex. However, none of the strains reacted with commercially available genetic probes for the M. avium complex. The strains were resistant to most antituberculosis drugs. Multilocus enzyme electrophoresis revealed two original electrophoretic types, which was suggestive of new species. The strains contained alpha-, keto-, and dicarboxylic mycolates, as determined by thin-layer chromatography. A mycolic acid analysis by high-performance liquid chromatography revealed a chromatographic pattern similar to that of M. xenopi, but distinct from the patterns of previously described Mycobacterium species. Hexadecanoic and tuberculostearic acids were identified as the major cell wall fatty acids by gas-liquid chromatographic analysis; hexacosanoic acid was the major mycolic acid cleavage product, and 2-eicosanol was the major alcohol. Evaluation of the 16S rRNA sequence confirmed the phylogenetic position of the organism among the slowly growing Mycobacterium species. Cultures representing this new species have been deposited in the American Type Culture Collection as strains ATCC 51130 and ATCC 51131T (T = type strain). The name Mycobacterium celatum is proposed.