Ldt(Mav2), a nonclassical transpeptidase and susceptibility of Mycobacterium avium to carbapenems

AIM: Mycobacterium avium infections, especially in immune-compromised individuals, present a significant challenge as therapeutic options are limited. In this study, we investigated if M. avium genome encodes nonclassical transpeptidases and if newer carbapenems are effective against this mycobacteria. MATERIALS & METHODS: Biochemical and microbiological approaches were used to identify and characterize a nonclassical transpeptidase, namely L,D-transpeptidase, in M. avium. RESULTS & CONCLUSION: We describe the biochemical and physiological attributes of a L,D-transpeptidase in M. avium, Ldt(Mav2). Suggestive of a constitutive requirement, levels of Ldt(Mav2), a L,D-transpeptidase in M. avium, remain constant during exponential and stationary phases of growth. Among β-lactam antibacterials, only a subset of carbapenems inhibit Ldt(Mav2) and tebipenem, a new oral carbapenem, inhibits growth of M. avium.