A comprehensive and contemporary "snapshot" of β-lactamases in carbapenem resistant Acinetobacter baumannii
Hujer AM, Hujer KM, Leonard DA, Powers RA, Wallar BJ, Mack AR, Taracila MA, Rather PN, Higgins PG, Prati F, Caselli E, Marshall SH, Clarke T, Greco C, Venepally P, Brinkac L, Kreiswirth BN, Fouts DE, Bonomo RA, Antibacterial Resistance Leadership Group (ARLG)
Successful treatment of Acinetobacter baumannii infections require early and appropriate antimicrobial therapy. One of the first steps in this process is understanding which β-lactamase (bla) alleles are present and in what combinations. Thus, we performed WGS on 98 carbapenem-resistant A. baumannii (CR Ab). In most isolates, an acquired bla carbapenemase was found in addition to the intrinsic bla allele. The most commonly found allele was bla (n = 78/98). In some isolates, bla was found in addition to other carbapenemase alleles: bla (n = 12/78), bla (n = 2/78) and bla (n = 1/78). Surprisingly, 20% of isolates carried carbapenemases not routinely assayed for by rapid molecular diagnostic platforms, i.e., bla and bla; all had ISAba1 elements. In 8 CR Ab, bla or bla was the only carbapenemase. Both bla and its variant bla were each found in 6/98 isolates. The most prevalent ADC variants were bla (21%), bla (21%), and bla (26%). Complete combinations are reported.