A novel and hybrid composite transposon at the origin of acquisition of bla(RTG-5) in Acinetobacter baumannii.
The genetic context of the gene coding for the novel variant of the class A β-lactamase RTG-5 (CARB-14), exhibiting two amino acid substitutions compared with the closest RTG-3 enzyme, was analysed in a clinical isolate of Acinetobacter baumannii. This novel variant exhibited a narrow-spectrum profile, as observed for RTG-3. Sequence analysis of the region flanking the 5' end of bla(CARB-14) identified a novel insertion sequence ISAba21 belonging to the IS3 family. Downstream of bla(CARB-14), another insertion sequence belonging to the IS3 family named ISAba14 was identified. Analysis of the left-end extremity of ISAba21 and the right-end extremity of ISAba14 identified direct repeat sequences of 3 bp, likely being the signature of a transposition process. This is one of the few examples of a composite transposon made of different insertion sequences bracketing a gene coding for this novel carbenicillinase.
Service de Bactériologie-Virologie, INSERM U914 Emerging Resistance to Antibiotics, Hôpital de Bicêtre, Assistance Publique/Hôpitaux de Paris, Faculté de Médecine et Université Paris-Sud, K.-Bicêtre, France.
Rémy A
RA
Bonnin
Laurent
L
Poirel
Patrice
P
Nordmann
D000151:Acinetobacter Infections / Q000382:microbiology; D040981:Acinetobacter baumannii / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics* / Q000302:isolation & purification; D000900:Anti-Bacterial Agents / Q000378:metabolism; D004251:DNA Transposable Elements; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D006801:Humans; D008826:Microbial Sensitivity Tests; D008969:Molecular Sequence Data; D017422:Sequence Analysis, DNA; D013379:Substrate Specificity; D001618:beta-Lactamases / Q000235:genetics*; D047090:beta-Lactams / Q000378:metabolism
D000900:Anti-Bacterial Agents; D004251:DNA Transposable Elements; D004269:DNA, Bacterial; D047090:beta-Lactams; D001618:beta-Lactamases