Expansion of plasmid mediated blaACT-2 among Pseudomonas aeruginosa associated with postoperative infection and its transcriptional response under cephalosporin stress

Authors : Birson İngti, Deepjyoti Paul ANAND PRAKASH MAURYA

Pages : 75-82

Doi:10.5799/jmid.vi.328788

View : 9 | Download : 5

Publication Date : 2017-06-01

Article Type : Research Paper

Abstract :Objectives: Organisms harboring multiple plasmid mediated β-lactamases are major concerns in nosocomial infections. Among these plasmid mediated β-lactamases, ACT insert ignore into journalissuearticles values(EBC family); is a clinically important enzyme capable of hydrolyzing broad spectrum cephalosporins. Therefore, the present study was undertaken to determine the prevalence of ACT determinant along with other co-existing β-lactamase genes in P. aeruginosa strains. Methods: A total of 176 Pseudomonas isolates were phenotypically screened for the presence of AmpC β-lactamase by M3DET Method followed by Molecular detection using PCR assay. Transcriptional evaluation of blaACT-2 gene was analyzed by RT-PCR and its transferability was performed by transformation and conjugation. Results: Present study demonstrates the presence of ACT-2 allele among 12 strains of P. aeruginosa. Co-existence of other β-lactamase genes were encountered among ACT-2 harboring strains which includes CTX-M insert ignore into journalissuearticles values(n=2);, SHV insert ignore into journalissuearticles values(n=3);, TEM insert ignore into journalissuearticles values(n=2);, VEB insert ignore into journalissuearticles values(n=2);, OXA-10 insert ignore into journalissuearticles values(n=1);, CIT insert ignore into journalissuearticles values(n=2); and DHA insert ignore into journalissuearticles values(n=3);. Fingerprinting by REP PCR revealed the isolates harboring ACT-2 to be distinct and these isolates showed high resistance to expanded-spectrum cephalosporins and even to carbapenem group of drugs. This ACT-2 allele was encoded in the plasmid insert ignore into journalissuearticles values(L/M, FIA, FIB Inc. Group); and conjugatively transferable. Transcriptional analysis revealed a significant increase in ACT-2 expression insert ignore into journalissuearticles values(483 fold); when induced by ceftriaxone at 4 µg/ml followed by ceftazidime at 8 µg/ml insert ignore into journalissuearticles values(31 fold); and cefotaxime 4 µg/ml insert ignore into journalissuearticles values(8 fold);. Conclusion: In this study detection of ACT-2 plasmid mediated AmpC β-lactamase along with other β-lactamase genes in clinical isolates of P. aeruginosa represents a serious therapeutic challenge. Therefore, revision in antimicrobial policy is required for effective treatment of patients infected with pathogen expressing this mechanism. J Microbiol Infect Dis 2017; 7insert ignore into journalissuearticles values(2);: 75-82
Keywords : Plasmid mediated, ACT 2 β lactamase, P aeruginosa