Occurrence and types of carbapenamase enzymes amongst enterobacterales and Pseudomonas spp. using automated phenotypic method

Abstract

The continuous rise of Carbapenem Resistant Organisms, considered as one of demanding public health issue. Carbapenemase producing organisms (CPO) can be detected by various molecular and phenotypic methods. Although molecular method shows higher accuracy, but is limited by relatively complex procedure and expensive regents. Thus, phenotypic methods considered as routine CPO detection method. Automated system Phoenix M50 (Becton & Dickinson) CARBA panels, provides the advantage of simultaneous identification and characterization of carbapenemase enzymes. A retrospective study was conducted for various clinical samples received at a tertiary care center in Western Maharashtra during a period of one year. The bacterial identification and antimicrobial susceptibility testing performed by automated system Phoenix M50 (Becton & Dickinson) CARBA panels. Isolates which flagged as carbapenemase producers were confirmed using modified carbapenemase inactivation method (mCIM) as a part of protocol. Among all isolates of enterobacterial and . 32% were carbapenemase producers. identified as predominant strain. Class B MBL was 46.4 % of isolates, consisting of appeared at 40% followed by at 35.5%. Class D beta-lactamase the second, the majority found in K.pneumoniae at 27.23%, followed by at 30 %. For Class A, 56 % followed by 26 % (n=67) isolates found in K.pneumoniae. The most isolates were Urine 16.6% followed by Pus 7.29 %, Respiratory 4% and blood 4%. A high occurrence of carbapenemase producers observed in the study is concerning. Moreover, most of them belonged to Class B MBLs, which demonstrated the need antibiotic stewardship and hospital infection control strategies to prevent their further spread.