Illegitimate recombination: An efficient method for random mutagenesis in Mycobacterium avium subsp. hominissuis

BMC Microbiology

Research Article

Ralph Kunisch¹  Astrid Lewin¹  Elisabeth Kamal¹  Faisal Asghar Khattak²  Ashutosh Kumar³ 

[1] Division 16 Mycology/Parasitology/Intracellular Pathogens, Robert Koch-Institute, Nordufer 20, 13353, Berlin, Germany;Division 16 Mycology/Parasitology/Intracellular Pathogens, Robert Koch-Institute, Nordufer 20, 13353, Berlin, Germany;Faculty of Biological Sciences, Islamia College Peshawar (a public sector University), KhyberPakhtunkhwa, Pakistan;Division 16 Mycology/Parasitology/Intracellular Pathogens, Robert Koch-Institute, Nordufer 20, 13353, Berlin, Germany;Pathogen Biology Laboratory, Department of Biotechnology, School of Life Sciences, Unversity of Hyderabad, Hyderabad, India;

关键词: Mycobacterium;    Mycobacterium avium;    Non-tuberculous mycobacteria;    Virulence;    Mutagenesis;    Illegitimate recombination;   

DOI  :  10.1186/1471-2180-12-204

 received in 2012-08-17, accepted in 2012-09-07,  发布年份 2012

来源: Springer

【 摘 要 】

BackgroundThe genus Mycobacterium (M.) comprises highly pathogenic bacteria such as M. tuberculosis as well as environmental opportunistic bacteria called non-tuberculous mycobacteria (NTM). While the incidence of tuberculosis is declining in the developed world, infection rates by NTM are increasing. NTM are ubiquitous and have been isolated from soil, natural water sources, tap water, biofilms, aerosols, dust and sawdust. Lung infections as well as lymphadenitis are most often caused by M. avium subsp. hominissuis (MAH), which is considered to be among the clinically most important NTM. Only few virulence genes from M. avium have been defined among other things due to difficulties in generating M. avium mutants. More efforts in developing new methods for mutagenesis of M. avium and identification of virulence-associated genes are therefore needed.ResultsWe developed a random mutagenesis method based on illegitimate recombination and integration of a Hygromycin-resistance marker. Screening for mutations possibly affecting virulence was performed by monitoring of pH resistance, colony morphology, cytokine induction in infected macrophages and intracellular persistence. Out of 50 randomly chosen Hygromycin-resistant colonies, four revealed to be affected in virulence-related traits. The mutated genes were MAV_4334 (nitroreductase family protein), MAV_5106 (phosphoenolpyruvate carboxykinase), MAV_1778 (GTP-binding protein LepA) and MAV_3128 (lysyl-tRNA synthetase LysS).ConclusionsWe established a random mutagenesis method for MAH that can be easily carried out and combined it with a set of phenotypic screening methods for the identification of virulence-associated mutants. By this method, four new MAH genes were identified that may be involved in virulence.

【 授权许可】

Unknown   
© Khattak et al.; licensee BioMed Central Ltd. 2012. This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.