Resumo

Introduction: A broad-host range multidrug resistance IncP-1β plasmid was identified in the strain of Mycobacterium abscessus subsp. bolletii that caused an epidemic of surgical-site infections in Brazil (2004-2008). The 56,264 pb plasmid from the epidemic reference strain INCQS 00594, named pMAB01, was sequenced using the SOLiD platform V3. Objectives: To verify the presence of pMAB01 in other M. abscessus subsp. bolletii isolates form the epidemic and in isolates from the same subspecies not related to this epidemic. Methods: The presence of pMAB01 in 15 M. abscessus subsp. bolletii epidemic isolates obtained from surgical-site infections, 24 isolates from other specimens and two reference strains, M. abscessus ATCC 19977 and M. massiliense CCUG 48898, was verified using PCR with primers derived from ten different regions of pMAB01 and Southern blot hybridization using the trfA amplicon as a probe. Results and discussions: Thirteen of the 15 surgical isolates and three isolates obtained from sputum, bronchoalveolar lavage and urine generated plasmid amplicons. These 16 isolates showed indistinguishable or highly related PFGE patterns. In the Southern blot hybridization analysis, 12 isolates showed a trfA1 hybridization band of ~50-kb, three isolates showed a hybridization band that migrated below the 50-kb molecular marker and, in one case, a hybridization band was detected near the origin of the gel. The remaining 25 isolates did not show any evidence of the presence of this plasmid. Conclusions: This is the first description of the presence of an IncP-1β plasmid in mycobacteria. pMAB01 is a circular molecule with variable migration in PFGE gels. pMAB01 appears to be restricted to the particular strain of M. abscessus subsp. bolletii that caused the epidemic of surgical infections and, to date, has not been detected in isolates showing other PFGE patterns. Acquisition of broad-host range multidrug resistance plasmids by ubiquitous mycobacteria could potentially generate mycobacterial strains that might be better adapted to causing human disease. Therefore, the role of this plasmid in the generation of outbreaks caused by environmental mycobacteria requires further investigation. Funding resources: Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)