Evaluation of the influence of the cultivation medium on the result of identification of microorganisms from the group of acid-resistant bacteria of the order actinomycetales by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry.

Background: Problem with mass spectrometers is the difficulty in identifying some genera of acid-fast bacteria (AFB). Due to the peculiarities of the colony architectonics (the formation of dry colonies with a complex structure) and the structure of the cell wall, the probability of obtaining a sufficient amount of ribosomal proteins is significantly reduced. This problem is partially solved using an extended method of direct application and extraction with formic acid, which can significantly improve the quality of the identification.

Comparison of laboratory methods for identifying members of the family .

Background: The introduction of a method based on matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry (MALDI-ToF mass spectrometry) into the practice of laboratories significantly increased the identification of acid-resistant bacteria (ARB).

Methods: Seventy-four nontuberculous mycobacteria (NTM) cultures identified by deoxyribonucleic acid (DNA) hybridization, polymerase chain reaction, Sanger sequencing, and MALDI-ToF mass spectrometry.

Results: Analysis of the identification results obtained by the methods of DNA hybridization and Sanger sequencing showed a complete match only for 67.

Application of chromogenic media for preliminary identification of acid-resistant bacteria.

Background: The variety of morphological and cultural characteristics of acid-resistant bacteria (ARB) makes it possible to use microscopy and estimate the growth rate and pigment formation when cultivating on solid egg media for preliminary identification only as additional indicative methods. It is necessary to develop new approaches for the cultivation and primary identification of ARB isolated from the biological material. It will allow to obtain data on the prevalence, structure, epidemiological, and clinical features of infectious processes caused by opportunistic ARB.

Evaluation of possibility of cultivation of acid resistant bacteria on solid egg-based and agar cultural media.

Background: The increase in the number of patients at risk for opportunistic infections caused by rare bacteria, which include individual representatives of acid-resistant bacteria (ARB), is a serious problem in modern health care. Significant difficulties in the etiological diagnosis of mycobacteriosis, nocardiosis, and actinomycosis are associated not only with the problem of identifying the main pathogens but also with certain difficulties in isolating pathogens from biological material.

Methods: The research provides data on 402 strains of ARB, which were isolated from various biological materials obtained from patients during examination for tuberculosis.