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

Abstract

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. The research provides data on 402 strains of ARB, which were isolated from various biological materials obtained from patients during examination for tuberculosis. All samples of biological material were negative on the Mycobacterium tuberculosis complex. The isolates were identified on the MALDI-ToF mass spectrometer. The cultural characteristics of ARB were evaluated on the solid Löwenstein-Jensen egg-based culture media, universal chromogenic media, and 5% blood agar with lamb blood. The studies carried out indicate the possibility of culturing ARB representatives on agar media. At the same time, based on the comparison of the growth properties of ARB, it was found that the universal chromogenic media provides more acceptable conditions for the isolation of nontuberculous mycobacteria (NTM) compared to blood agar. The comparison of the growth rate of bacteria did not reveal significant differences for fastly growing NTM. For slowly growing species, the growth rate on blood agar was lower than on chromogenic media and on the Löwenstein-Jensen media. Thus, the use of a universal chromogenic media during incubation makes it possible to isolate and preidentify representatives of the ARB under the conditions of standard operating procedures of the microbiological laboratory.