Feature of Adhesins Produced by Human Clinical Isolates of Mycobacterium intracellulare, Mycobacterium intracellulare subsp. chimaera and Closely Related Species.

Louise H Lefrancois,Cyril Conde,Olivia Peuchant,Camille Locht,Franck Biet,Philippe Lanotte,Maxime Branger,Thierry Cochard,Adeline Pastuszka

doi:10.3390/microorganisms8081154

Abstract

The Mycobacterium avium complex includes two closely related species, Mycobacterium avium and Mycobacterium intracellulare. They are opportunistic pathogens in humans and responsible for severe disease in a wide variety of animals. Yet, little is known about factors involved in their pathogenicity. Here, we identified, purified and characterized adhesins belonging to the heparin-binding hemagglutinin (HBHA) and laminin-binding protein (LBP) family from M. intracellulare ATCC13950 and examined clinical isolates from patients with different pathologies associated with M. intracellulare infection for the presence and conservation of HBHA and LBP. Using a recombinant derivative strain of M. intracellulare ATCC13950 producing green fluorescent protein and luciferase, we found that the addition of heparin inhibited mycobacterial adherence to A549 cells, whereas the addition of laminin enhanced adherence. Both HBHA and LBP were purified by heparin-Sepharose chromatography and their methylation profiles were determined by mass spectrometry. Patients with M. intracellulare infection mounted strong antibody responses to both proteins. By using PCR and immunoblot analyses, we found that both proteins were highly conserved among all 17 examined clinical M. intracellulare isolates from patients with diverse disease manifestations, suggesting a conserved role of these adhesins in M. intracellulare virulence in humans and their potential use as a diagnostic tool.

Highlights

Non-tuberculous mycobacteria (NTM) are an increasing cause of opportunistic diseases in humans [1,2]
Adherence of M. intracellulare to Epithelial Cells is Modulated by Heparin and Laminin
One of the major outcomes of this study is the first characterization of heparin-binding hemagglutinin (HBHA) and laminin-binding protein (LBP) of

Summary

Introduction

Non-tuberculous mycobacteria (NTM) are an increasing cause of opportunistic diseases in humans [1,2]. Among NTM, the Mycobacterium avium complex (MAC) represents a group with a specific distribution of species according to continent and countries [3]. In addition to severe infection in immune-deficient subjects, such as AIDS patients, the incidence of MAC infections has recently increased in patients with chronic pulmonary disease and other underlying conditions [4,5]. Some recently discovered species are very close to M. intracellulare and are termed M. intracellulare subsp. Chimaera are associated with infections in humans. M. intracellulare is mainly implicated in pulmonary infections, and M. intracellulare subsp. Chimaera [12], was recently associated with fatal infections after cardiac surgery [13]. GenoType NTM-DR, a new commercial diagnostic assay, allows differentiation between three MAC species, M. avium, M. intracellulare, M. intracellulare subsp. Mass spectrometry has been recently proposed as a useful tool to identify these NTM at the species level [15]

Methods

Results

Conclusion