Emergence of the Uncommon Clone ST944/ST78 Carrying bla(OXA-40-like) and bla(CTX-M-like) Genes Among Carbapenem-Nonsusceptible Acinetobacter baumannii in Moscow, Russia

摘要

Carbapenem-nonsusceptible (Carba-NS) Acinetobacter baumannii has emerged as an important cause of nosocomial infections. In the present study, we characterized 91 Carba-NS A. baumannii isolates collected from patients of surgical departments and intensive care units at three hospitals in Moscow in 2012-2015. Multilocus sequence typing (MLST) using the Oxford (Oxf) scheme identified 16 sequence types (STs) of three clonal complexes (CCs), including CC92(Oxf) (67%), CC109(Oxf) (1%), CC944(Oxf) (29%), and the singleton ST1100(Oxf) (3%). CC944(Oxf) was composed of ST944(Oxf) (n = 16) and two of its newly described single locus variants ST1103(Oxf) (n = 3) and ST1104(Oxf) (n = 7); all the three STs were identical to the Pasteur (Pas) MLST scheme ST78. All CC944(Oxf)/ST78(Pas) isolates were bla(OXA-40-like) positive and all but one isolate harbored a bla(CTX-M-like) gene. ST944(Oxf) was the only ST found in each of the three study hospitals. Biofilm growth capacity was similar among Carba-NS and nonclonal carbapenem-susceptible isolates. Our data demonstrate the predominance of two clonal lineages among Carba-NS A. baumannii. One of these, the uncommon bla(OXA-40-like)/bla(CTX-M-like)-positive clone of CC944(Oxf)/ST78(Pas), seems to be endemic in Russia.