Distribution of carbapenem resistant Acinetobacter baumannii with blaADC-30 and induction of ADC-30 in response to beta-lactam antibiotics

Publication date: Available online 25 January 2020Source: Research in MicrobiologyAuthor(s): Birson Ingti, Supriya Upadhyay, Monalisha Hazarika, Annie Bakorlin Khyriem, Deepjyoti Paul, Prithwis Bhattacharya, S.R. Joshi, Debajyoti Bora, Debadatta Dhar (Chanda), Amitabha BhattacharjeeAbstractA wide range of intrinsic Acinetobacter-derived cephalosporinases (ADC) along with other carbapenemases has now been detected in Acinetobacter baumannii leaving clinicians with few treatment options. The present study reports the spread of ADC-30 co-producing KPC-2 along with other β-lactamases among carbapenem resistant A. baumannii strains obtained from ICU patients in two Indian hospitals. Primer extension analysis revealed higher transcript level of the ADC gene when induced with cefoxitin at 8μg/ml (170 fold), ceftriaxone at 8μg/ml (136 fold), ceftazidime at 4μg/ml (65 fold), cefepime at 8μg/ml (77 fold) and aztreonam at 8μg/ml (21 fold) when compared with the basal level without antibiotic pressure. Slight increase in expression of blaADC-30 when induced with imipenem and meropenem at 0.25μg/ml (3 and 6 fold) was observed and may help in conferring resistance to carbapenem. MLST analysis revealed the circulation of A. baumannii sequence types ST188, ST386, ST583 and ST390 in these hospitals.
Source: Research in Microbiology - Category: Microbiology Source Type: research