Names for mycobacteria

Infection withMycobacterium simiaecomplex in four captive Micronesian kingfishers

CASE DESCRIPTION

4 captive adult Micronesian kingfishers (Halcyon cinnamomina cinnamomina) at 3 zoologic institutions were examined routinely or because of dyspnea or lethargy.

CLINICAL FINDINGS

All birds had marked hepatomegaly. Two birds had dyspnea caused by compression of air sacs by the enlarged liver, and 1 bird had generalized weakness and lethargy. Three birds had distended coelomic cavities, and 3 birds were thin or had lost weight. There were no consistent abnormalities in blood analytes. Results of most ancillary diagnostic tests such as acid-fast staining of cloacal or fecal swab specimens and culture of feces for acid-fast bacteria were negative. Results of examination of hepatic biopsy specimens in 2 of 4 birds were suggestive of mycobacteriosis.

TREATMENT AND OUTCOME

3 birds died or were euthanized soon after diagnosis. One kingfisher was isolated and monitored for 4 months without treatment and died during anesthesia for disease monitoring. Postmortem histologic examination revealed histiocytic hepatitis and acid-fast bacteria in all 4 birds. Bacteriologic culture of liver specimens yielded Mycobacterium simiae complex in all 4 birds.

CLINICAL RELEVANCE

Infection with M simiae complex should be considered in ill Micronesian kingfishers, and further monitoring is warranted to determine whether this is an emerging pathogen in this species.

Isolation of non-tuberculosis mycobacteria in treated dental unit waterlines

OBJECTIVE

The purpose of the study was to investigate the presence of non-tuberculosis mycobacteria (NTM) in dental unit waterlines that were being routinely treated with an intermittent use waterline cleaner.

STUDY DESIGN

The study was conducted at a hospital dentistry clinic where immunocompromised patients are seen. Water samples from two lines on one of two dental units were taken before and after routine weekend chemical treatment. Sampling was repeated on two subsequent occasions, on the same unit, at three monthly intervals. Laboratory techniques included centrifugation and membrane filtration to detect small numbers of organisms.

RESULTS

Mycobacterium simiae was isolated from one of the four pre-treatment samples and from two of the four post-treatment samples. Mycobacterium mucogenicum was isolated from one of the four post-treatment samples.

CONCLUSIONS

This pilot study found that NTM were present in DUWLs that were being routinely treated with an intermittent use chemical cleaner. Practitioners are urged to understand the limitations of available DUWL treatments, and to consider the use of sterile water for non-surgical, as well as surgical, treatment of immunocompromised patients.

Bovine tubercle bacilli and disease in animals and man

In 1882 Robert Koch reported the isolation oftuberkelbazillenfrom human and bovine sources. Sixteen years later, Theobald Smith (1898) demonstrated that strains of Koch's tubercle bacilli from these two hosts differed in cell morphology, cultural characteristics and virulence in rabbits. He did not believe that these variants were limited to the hosts from which they were isolated nor that the differences resulted from adaptations to a given host. Indeed, he remarked that ‘It might be better to omit the host designation of such varieties in order to anticipate assumptions that they are necessarily limited to the host whose name they bear.’ Nevertheless, heedless of his own misgivings he termed them the ‘human’ and ‘bovine’ types.

The nature of mycobacterial disease in south east England, 1977-84

The nature and incidence of bacteriologically confirmed mycobacterial disease in south east England over the eight year period 1977-84 has been determined by a study of cultures received by the PHLS Regional Centre for Tuberculosis Bacteriology at Dulwich. The number of cases of tuberculosis in the ethnic European population has shown a decline, more so among males than females, but there has not been a significant decline in cases among ethnic Asians. Most tuberculosis is due to the classical human tubercle bacillus but cases due to the Asian human type, the bovine type (M. bovis), and the African types (M. africanum) also occur. The number of cases of disease due to 'atypical' mycobacteria has doubled over the eight year period, and these now account for about 5% of bacteriologically diagnosed mycobacterial disease in this region. The continuing role of reference facilities for the surveillance of tuberculosis and the diagnosis and management of the growing numbers of other mycobacterial infections is stressed.

Subdivision of Mycobacterium tuberculosis for epidemiological purposes: a seven year study of the "Classical' and 'Asian' types of the human tubercle bacillus in South-East England

Human strains of Mycobacterium tuberculosis were divided into the 'Classical' and 'Asian' types according to their sensitivity to thiophen-2-carboxylic acid hydrazide. The isolation of these two types in South-East England was studied during a seven-year period (1977-1983). The 'Asian' type was more prevalent among ethnic Asian patients than among ethnic Europeans. Among Europeans there was a decline in the isolation rate of 'Classical' strains and a small but significant increase in 'Asian' strains during the study period, so that the proportion of the latter type in this group is increasing. The type of bacillus was unrelated to the site of isolation except that the incidence of lymphadenitis due to the 'Asian' type among European females was significantly higher than expected. In general, European patients tended to be older than Asian patients, and the differences in age distribution according to site of isolation and type of bacillus in each ethnic group were small. A notable exception occurred with European females infected with the 'Asian' type, whose age distribution was similar to the Asians. In view of the differences in behaviour of the two types of human tubercle bacilli in this country there is a need to continue a bacteriological surveillance and also to determine whether the nature of the host-pathogen interaction varies according to the type of bacillus.