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PubMed1979

Influence of pork consumption on human infection with Mycobacterium avian-intracellulare.

The hypothesis that eating pork from animals infected with organisms of the Mycobacterium avium-intracellular complex is a significant cause of human mycobacteriosis was examined by skin testing students with purified protein derivative from M. intracellulare to determine their sensitivity to M. avium-intracellulare. No significant differences in sensitivity could be demonstrated between those individuals who had never eaten pork and those who ate pork routinely. It was concluded that sensitivity to purified protein derivative from M. intracellulare in this population did not involve eating pork.

Animals↗
PubMed1978

Effect of repeated injections of iron dextran on the haematological, serological and pathological changes in experimental avian tuberculosis.

Eight intramuscular injections of 200 mg/kg of iron (DFe), given as iron dextran twice weekly in the week before and the three weeks after intravenous infection with about 10(7.5) colony-forming units of Mycobacterium avium, significantly prolonged (by about 11 days) the mean 'time-to-death' of immature male fowl (Gallus domesticus) compared with corresponding regimes using dextran (Dx) only or saline, When a proportion of the birds were examined 21 days after infection many of the abnormalities associated with the disease, including a marked hypochromic anaemia, were less severe in DFe-treated than in the Dx- or saline-treated chicks and there were about 10- to 85-fold fewer viable tubercle bacilli in the liver and spleen of the DFe-treated birds.

Animals↗
PubMed1979

Laboratory diagnosis of bovine tuberculosis.

Lesions of suspected bovine tuberculosis were examined by culture, histopathology and auramine-O (AO) stained smears and the findings correlated with field aspects of the disease. Of 642 lesions considered to be tuberculous, 62.0% yielded M. bovis and 4.5% other mycobacteria (OM). M. bovis and OM were recovered also from 0.6% and 3.6% respectively of 165 cattle which gave tuberculin reactions but had no visible lesions at slaughter. Of 262 lesions in which a histopathological diagnosis other than tuberculosis was made, 1.5% and 3.0% yielded M. bovis and OM respectively. All OM isolates tested belonged to the Mycobacterium-avium-intracellulare-scrofulaceum (MAIS) complex with a predominance of serotype 2. A good relationship was found between the recovery of mycobacteria and histopathology but examination of smears revealed 22.0% apparent false negatives. Apparent false negative culture results were also reported for 35.8% of lesions positive on histopathology and smear examination. The majority of herds yielding M. bovis contained reactors to the tuberculin test and many of these had lesions of tuberculosis. In contrast, herds yielding OM seldom contained reactors to the tuberculin test and rarely reactors with tuberculous lesions. The thoracic cavity was the main site of lesions from infections by M. bovis and OM.

Animals↗
PubMed1979

Reliable urease test for identification of mycobacteria.

A simple, modified formation for urea broth gave consistent, reliable results to aid in the differentiation of Mycobacterium species. In a study of 1,346 isolates representing 17 different species, tests read after 7 days were distinct and reproducible. The use of this test facilitates the identification of Mycobacterium species, such as M. scrofulaceum, the M. avium complex, the M. terrae complex, and M. triviale.

Bacteriological Techniques↗
PubMed1975

Tuberculosis of the cervical lymph nodes : a clinical, pathological and bacteriological study.

Biopsies taken from the lymph nodes of 59 consecutive patients with cervical lymph node tuberculosis were examined bacteriologically and histologically. The series consisted of 18 men (mean age 40 years) and 41 women (mean age 46 years). Mycobacteria were isolated from 41 specimens (69 per cent), M. tuberculosis from 40 patients and a mycobacterium of the M. avium-M. intracellulare complex from one. All the M. tuberculosis strains were sensitive to streptomycin, isoniazid and PAS. No mycobacteria were isolated from the biopsy specimens of the 10 patients who had received anti-tuberculosis drug previously. Mycobacteria were isolated equally often from caseating and non-caseating lymph nodes. In 10 specimens acid-fast bacilli could be demonstrated by staining, but attempts at isolation were unsuccessful. Nine of these 10 patients had been treated with anti-tuberculosis drugs previously. Histological examination of the specimen from which a growth of 'atypical' mycobacteria had been obtained failed to show any distinctive features. The results of treatment are given over a follow-up period of 2 years. Primary chemotherapy was not entirely successful. Of 52 patients treated in this way only 38 responded well. By contrast 19 patients were treated by a combination of chemotherapy and surgery and the outcome was satisfactory in all but one.

Adult↗
PubMed1979

Identification of clinical isolates of mycobacteria with gas-liquid chromatography alone.

Identification of 18 mycobacterial species was performed by analysis of profiles obtained by using gas-liquid chromatography. Organisms were saponified in methanolic NaOH, and the reaction mixture was treated with BF(3) in methanol and extracted with a hexane-chloroform mixture. An identification scheme was developed from 128 stock strains and tested against a collection of 79 clinical isolates. By using gas-liquid chromatographic profiles alone, 58% of specimens were correctly identified to species level, and an additional 41% were correctly identified to a group of two or three organisms. Use in a clinical laboratory over a 2-month period proved chromatography to be as accurate as and more rapid than concurrent biochemical testing. Of 81 isolates tested, 64% were identified to species level by chromatography alone. An additional 35% were differentiated to the same groups of two or three organisms as found in our analysis of stock strains. These groups consisted of: Mycobacterium tuberculosis, M. bovis, and M. xenopi; M. avium complex, M. gastri, and M. scrofulaceum; or M. fortuitum and M. chelonei. Identification to species level from these groups could usually be done by colonial morphology alone and could always be done by the addition of one selected biochemical test. This study demonstrated the practical application of gas-liquid chromatography in the identification of mycobacteria in a clinical laboratory. In particular, all strains of M. gordonae and M. kansasii were identified to species level. M. tuberculosis was definitively identified in 85% of cases. When it could not be definitely identified, the only alternatives were M. bovis and M. xenopi, both of which are rare causes of infection.

Chromatography, Gas↗
PubMed2025

Species distribution of nontuberculous mycobacteria isolated from respiratory specimens at a tertiary care hospital in South Korea, 2017-2022.

The clinical relevance and drug resistance patterns of nontuberculous mycobacteria (NTM) vary by species. This study investigated the species distribution of NTM isolated from respiratory specimens at a tertiary care hospital in South Korea from 2017 to 2022. A retrospective analysis was conducted on laboratory data from respiratory specimens submitted for acid-fast bacilli culture. NTM isolates were identified using a line probe assay, and those unidentifiable at the species or complex level underwent multigene sequencing of the 16S rRNA, rpoB, and hsp65 genes. Among all mycobacterial isolates, the proportion of NTM showed an increasing trend, rising from 87.4% in 2017 to 93.3% in 2022. The eight most common species were M. avium complex (61.9%), M. abscessus (14.2%), M. fortuitum complex (8.4%), M. gordonae (5.3%), M. simiae complex (3.4%), M. kansasii complex (1.9%), M. terrae complex (1.5%), and M. chelonae (1.2%), accounting for 97.7% of all NTM isolates. Among the remaining isolates (2.3%, n = 169), 161 were classified into 24 species and groups, the majority with proportions below 0.1%. Two of the eight isolates that could not be identified at the species or group level despite multigene sequencing underwent whole-genome sequencing, which suggested they likely represent novel Mycobacterium species. This study provides valuable insights into the distribution of NTM species, particularly rarely encountered species, isolated from respiratory specimens in South Korea. These findings may aid in optimizing diagnostic strategies and selecting appropriate treatment options.IMPORTANCEGiven the significant variations in clinical relevance and drug resistance patterns among nontuberculous mycobacteria (NTM) species, understanding their geographic distribution is essential for selecting appropriate treatment options and improving patient outcomes. This study investigated the distribution of NTM species isolated from respiratory specimens at a tertiary care hospital in South Korea from 2017 to 2022. Our findings revealed an increasing proportion of NTM, with M. avium complex and M. abscessus remaining predominant. Additionally, we identified 24 rarely encountered species and groups, along with two strains that likely represent novel Mycobacterium species. Our study advances the understanding of the evolving NTM epidemiology in South Korea, contributing to the optimization of diagnostic strategies and improvement of patient management.

Republic of Korea↗
PubMed2026

Comparative evaluation of molecular technologies for the identification of prevalent non-tuberculous mycobacteria in pulmonary infections: a systematic review and meta-analysis.

BACKGROUND: The increasing prevalence of non-tuberculous mycobacteria pulmonary disease (NTM PD) is a burden to public health. Successful management of NTM PD critically depends on accurate species identification and reliable drug susceptibility testing to guide appropriate antibiotic therapy. Emerging molecular technologies offer rapid diagnostic solutions compared to conventional methods, but their performance varies. This study aims to provide a comprehensive evaluation of current molecular techniques for NTM identification and to present a global antibiotic resistance profile. METHODS: A systematic literature search was conducted in PubMed and Web of Science for studies published between 2005 and 2024. Studies applying molecular methods for NTM identification and resistance detection in humans were included. Data on study characteristics, diagnostic methods, sample types, sample sizes, identification sensitivity, and drug susceptibility results were extracted. Meta-analysis was performed using R with the meta4diag package. The quality of included studies was assessed using the QUADAS-2 tool. RESULTS: The analysis included 49 studies on NTM identification and 33 studies on antibiotic resistance. For species identification, all evaluated molecular technologies (MALDI-TOF MS, PCR-based methods, Sequencing, DNA chip, and DNA strip) demonstrated high pooled sensitivities (>0.92). Subgroup analysis revealed that sample type significantly affected performance for MALDI-TOF MS. Preliminary analysis of antibiotic resistance rates revealed varying patterns. For slowly growing mycobacteria, a significantly high Ethambutol resistance rate was observed in M. avium (69.20%). Among rapidly growing mycobacteria, resistance to Imipenem was notable (54.22%), and Clarithromycin resistance varied significantly within the Mycobacterium abscessus complex. CONCLUSION: Emerging molecular technologies have revolutionized the methodology for NTM identification with excellent performance. However, their performance can be influenced by sample type, particularly for MALDI-TOF MS. The alarming and heterogeneous antibiotic resistance patterns also highlight the critical need for rapid and accurate species identification and drug susceptibility testing to inform effective therapeutic strategies. Key messagesMolecular technologies demonstrate high accuracy for NTM identification.Antibiotic resistance is a serious concern with variations among NTM species and subspecies.Rapid and accurate species identification and drug susceptibility testing are crucial for guiding effective clinical management of NTM PD.

Humans↗
PubMed1975

Isolation of acid-fast organisms from milk and oysters.

Raw and pasteurized milk, as well as oysters collected from approved growing areas, were cultured for the presence of acid-fast organisms. Mycobacteria and nocardia were isolated from 68.8% of the raw milks, but none from the 43 pasteurized specimens. The 66 isolations were identified as follows: one M. marinum, two M. scrofulaceum, nine M. gordonae, seven M. flavescens, nine M. avium---M. intracellulare complex, 18 M. terrae complex, 12 M. fortuitum, six M. "parafortuitum" complex, and two Nocardia asteroides. From nine pooled samples of oysters 15 mycobacterial strains were cultured. These strains were identified as follows: three M. scrofulaceum, five M. gordonae, two M. avium--M. intracellulare complex, two M. terrae complex and three M. "parafortuitum" complex.

Animals↗
PubMed1979

Infections with Mycobacterium malmoense in England and Wales.

Mycobacterium malmoense has been isolated from 11 patients in England and Wales. It was thought to be the cause of pulmonary disease in 9 of them and cervical adenitis in 2. The cultural and biochemical characters of the species are described and its position in relation to the avium-intracellulare complex and the non-chromogenicum-terrae-triviale complex determined by matching coefficients using 88 characters. Brief details are given of the 11 cases.

Aged↗
PubMed1979

Occurrence and characterization of "avium-like" Mycobacteria isolated from animals in Sweden.

431 cultures of "avium-like" mycobacteria (ALM) were isolated from wild and domestic animals during 1974--76 at the National Veterinary Institute, Stockholm. Of these, 50 isolates from pigs were studied by growth-chromogenicity, pathogenicity, and biochemical tests. Furthermore, thin-layer chromathography was performed, and on some isolates serotyping. All 50 isolates belonged to Runyon's group III and were pathogenic for chicken; none was capable of splitting oleic acid from Tween 80. 47 gave tellurite reduction within a period of three days; one was arylsulphatase-positive after three days and a further four after 14 days. The biological and biochemical tests permit assignation of the 50 isolates to the M. avium-intracellulare complex. The lipid patterns of the isolates examined were analysed by thin-layer chromatography. Thirty-five of the isolates showed a lipid pattern similar to that of A 2 of the fowl reference strain; three belonged to lipid type A 1 and four to A 3. Eight could not be typed. Of 22 isolates, 14 could be assigned to M. avium serotypes.

Animal Population Groups↗
PubMed1977

Studies on mycobacteria isolated from animals, with special reference to the agglutination test.

Ninety-three strains of slowly-growing mycobacteria were studied biochemically. Ninety of these were isolated from animals (pigs, cattle, dog and poultry) and three from dust and sawdust-bedding in a pighouse. One strain from a lymph node of a pig was identified as M. gordonae. Ninety-two strains fitted into the M. aviam-intracellulare complex. Of the 92 biochemically confirmed M. avium-intracellulare strains, 78 were tested serologically ad modum Schaefer. Of 73 strains from pigs, one was serotype 1, fifty serotype 2 and eight serotype 8, while two could not be type and twelve were autoagglutinable. Three strains from pighouse environment were serotype 8 and two from cattle and a dog were both serotype 2. A slight modification of Schaefer's agglutination method, using smaller amounts of antigen and antiserum, was developed.

Agglutination Tests↗