Biomedical subjects
Publications and source records attributed to H Gruft.
Mycobacteria biochemically and serologically similar to those isolated from humans have been found in estuaries and ocean waters in the south-eastern United States. This is consistent with the hypothesis that aerosols from these waters are one potential source of infection with these mycobacteria.
The properties of an unusual catalase isolated from Aspergillus niger are reported. The enzyme, which has a molecular weight of 323,000, consists of four subunits and is highly resistant to sodium azide.
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In a proficiency testing program, slides bearing acid-fast bacilli were sent to laboratories in New York State. The most reliable results were obtained in laboratories using the Ziehl-Neelsen method. Cold staining procedures were less reliable. The auramine-rhodamine fluorescent stain, which produced many false positives, should be confirmed by the Ziehl-Neelsen procedure. The testing program described can be used to determine whether laboratories perform the acid-fast stain effectively.
The Tween opacity test can be used to differentiate (1) Mycobacterium flavescens from Mycobacterium gordonae and Mycobacterium szulgai, and (2) nonphotochromogenic strains of Mycobacterium kansaii from strains of the Mycobacterium terrae complex.
With the change in the management of tuberculosis, many bacteriology laboratories should be prepared to examine sputum for the presence of acid-fast bacilli. The niacin test is the most reliable test that can be performed in any mycobacteriology laboratory to differentiate Mycobacterium tuberculosis from the other acid-fast bacilli, but it is not perfect. Other tests can be used to supplement it are cord formation, growth at 24 C, and the catalase test at 68 C. Incompletely identified strains should be submitted to a reference laboratory.
The New York State Department of Health proficiency testing program in mycobacteriology determines the ability of a laboratory to isolate the acid-fast bacillus present in a simulated specimen and to identify the strain. Until 1964 the specimens were autoclaved normal sputa seeded with mycobacteria. When mandatory testing was introduced by law in 1964, more specimens were needed. These have been prepared in simulated sputum bases, first skimmed milk, then granulated hog gastric mucin. The bases are seeded with Mycobacterium tuberculosis and other mycobacteria; Pseudomonas aeruginosa is added to simulate the contamination in clinical specimens. Laboratory performance in general has improved as a result of the proficiency testing and the concomitant educational program, but laboratories processing more than 200 specimens a year continue to perform best.
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Explore the source record for details and available documents.