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Biomedical subjects

J H Bates

Publications and source records attributed to J H Bates.

At least 199 records · Page 11Linked to original sources
PubMed1978

An outbreak of histoplasmosis at an Arkansas courthouse with five cases of probable reinfection.

An outbreak of histoplasmosis occurred at a county courthouse in Arkansas in July, 1975. Fifty cases were identified by symptoms and positive complement fixation (CF) tests and 18 others by the clinical findings alone. Only three positive CF tests (greater than or equal to 1:8) were found in a control group of 55 unexposed persons of the same age. The attack rate for 84 courthouse employees was 52%. Histoplasma capsulatum was isolated from the sputum of two cases, and from bird droppings which had been dumped from the roof of the courthouse two weeks before the epidemic's peak. Window air conditioners apparently helped to distribute infectious particles throughout the building. Nine exposed people had pulmonary calcifications and a negative tuberculin test that were taken as presumptive evidence of previous histoplasmosis. Five (55%) of these became ill. Exposed persons without pulmonary calcifications had an attack rate of 85%. The reinfected cases during convalescence had higher serum CF titers but not larger histoplasmin skin test diameters than the rest of the cases. A microdroplet aerosol of cooking oil was used to simulate air flow patterns during the exposure, and the results agreed with the hypothesized means of infection.

Adult↗
PubMed1977

Shifting tuberculosis care to the general hospital.

Control of tuberculosis infection within the hospital is of major importance to general hospitals that assume the responsibility for providing tuberculous patients with primary care services. Because patients vary in their potential infectiousness, each patient's disease should be assessed individually. Patients who have completed a prescribed course of treatment are not infectious, and no precautionary measures are indicated. Patients with positive sputum who are receiving chemotherapy are rarely infectious, but they should be lodged in a room with air control. Effective antituberculous chemotherapy and adequate ventilation of the environment are the most important means of achieving infection control. Each hospital should have an infection control committee that is responsible for implementing infection control policies and for ensuring that patients with tuberculosis receive high-quality medical care. Educating personnel about tuberculosis, providing necessary consultation services, and making sure that patients are referred properly at discharge are important functions of the committee. Only those hospitals that are willing to meet these minimum standards should assume this responsibility.

Ambulatory Care↗
PubMed1976

Evidence for host-dependent modification and restriction of bacteriophage DNA in Mycobacterium tuberculosis.

Wild isolates of Mycobacterium tuberculosis may be divided into the three internationally recognized phage types on the basis of susceptibility to mycobacteriophages DS6A, BK1 and D34. Strains of type A are lysed at high efficiency by DS6A only; type B is lysed by BK1 grown on Mycobacterium smegmatis ATCC607 and DS6A, while type C is lysed additionally by D34 grown on atypical Mycobacterium F130. Propagation of D34 on a C-strain (D34-C) or BK1 on a B-strain (BK1-B) has no effect on viral host-range. D34-C has an efficiency of plating (e.o.p.) of 10(-5) on type B strains and 10(-7) on A strains. BK1-B plates on A strains at an e.o.p. of 10(-5). BK1 recovered from and repropagated on an A strain (BK1-A) has an e.o.p. of 1-0 on strains of all classes. D34-B has an e.o.p. of 1-0 on strains of type B and C, while D34-A plates with high efficiency on types B and C and displayed an e.o.p. of 10(-4) on type A. Repropagation of these viruses on the M. tuberculosis strains originally lysed by them results in the restoration of their previous host range. Variations in plating efficiency cannot be explained by differences in viral absorption alone. These findings suggest that the three phage types of human tubercle bacilli are related by a hierarchical pattern of DNA restriction and modification in which the C pattern is included in the B, and both patterns are included in A-modified DNA. Viruses such as DS6A which are equally virulent for strains of all classes are not susceptible to host dependent restriction.

Bacteriophage Typing↗
PubMed1976

Phage type of tubercle bacilli isolated from patients with two or more sites of organ involvement.

To evaluate the possibility of separate pulmonary infections in human beings by different strains of Mycobacterium tuberculosis, a search for multiple phage types within a single host was under-taken. Culture isolates from 2 or more distinct anatomic sites of infection in the same patient were obtained from 87 persons. In 3 subjects, 2 distinct phage types were found. The possible explanations for 2 types in the same patient and the epidemiologic implications are discussed.

Adult↗
PubMed1975

World Health Organization studies on bacteriophage typing of mycobacteria. Subdivision of the species Mycobacterium tuberculosis.

The ability of lytic mycobacteriophages to subdivide the species Mycobacterium tuberculosis reliably has been studied using a series of 100 strains isolated from cases of tuberculosis in the Netherlands. Techniques for the propagation and application of the viruses have been standardized, as have the conditions for growth and preparation of bacterial strains. On the basis of lytic results with 11 mycobacteriophages, it is proposed that the species Mycobacterium tuverculosis may be subdivided into at least 3 major phage types, A, B, and C, and into 2 subjects, Ax and A2. The reliability of the individual bacteriophage lytic result has been assessed, and the relationship between phage reliability and the degree of certainty with which a strain may be assigned to a phage type is described. The effect of rigorous standardization of techniques on the reliability of bacteriphage typing is demonstrated, and a standard protocol is proposed.

Bacteriophage Typing↗
PubMed1975

Evidence for infection by two distinct strains of Mycobacterium tuberculosis in pulmonary tuberculosis: report of 9 cases.

The sputum cultures of 26 patients in whom bacteriologic relapse occurred during or after an initial course of treatment with antimicrobial drugs were compared by phage typing with cultures isolated previously from the same patients. Nine (34 per cent) were different in phage type. Whether this indicates exogenous reinfection as the mechanism for the relapse, the presence of two distinct phage types present from the outset, or change in phage type of the original single strain has not been determined. These observations may have implications relating to epidemiology and control of tuberculosis.

Bacteriophage Typing↗
PubMed1973

WHO cooperative studies on the phage-typing of mycobacteria. 1. Phage lysis of Czechoslovak and Italian strains of Mycobacterium tuberculosis.

Although phage-typing of some pathogenic microbes-e.g., Escherichia coli and the genera Salmonella, Staphylococcus, and Streptomyces-is in routine use, little progress has yet been made in the phage-typing of mycobacteria, chiefly because mycobacteriophages possess a polyvalence that prevents the reliable identification of individual species of mycobacterium. Furthermore, laboratories cannot compare their results because they employ different methods and culture media and also because the phages used cannot be accurately identified. It has been shown that internationally reproducible results can be obtained for M. tuberculosis by selecting suitable mycobacteriophages and sensitive culture media, and by using a standardized technique of phage-typing. Under these conditions, phage lysis may be utilized to classify strains of M. tuberculosis.

Bacteriophage Typing↗
PubMed1971

Effect of rapid intravenous infusion on serum concentrations of amphotericin B.

The magnitude of the concentrations of amphotericin B produced in serum of patients with systemic mycoses may significantly influence the outcome of therapy with this drug. Since amphotericin B is conventionally administered in intravenous infusions lasting 4 to 6 hr, we asked whether faster infusions of this drug might yield higher serum concentrations without an increase in dose. This question was studied in three patients who received 16 infusions of this drug: eight infusions administered slowly (5 hr) and eight administered rapidly (45 min). Serum concentrations after each rapid infusion were compared with those after a slow infusion administered to the same patient. The mean serum concentration of amphotericin B 1 hr after the rapid infusions (2.02 mug/ml) was significantly higher (P < 0.001) than the mean serum concentration of amphotericin B 1 hr after the slow infusions of this drug (1.18 mug/ml). Mean serum concentrations 18 and 42 hr after rapid infusion remained slightly but not significantly higher than respective mean concentrations after slow infusions. By yielding higher initial serum concentration, rapid intravenous infusion may be therapeutically more effective than slow infusion of amphotericin B. Although rapid infusions caused no more toxicity than did slow infusions, the lack of greater toxicity with rapid infusion of amphotericin B should be further documented prior to extensive clinical application of this procedure.

Amphotericin B↗