Evaluation of multiple antibiotic resistance (MAR) index and Doxycycline susceptibility of Acinetobacter species among inpatients

Abstract

Background: Acinetobacter contributes to increased morbidity and mortality with its strong propensity to colonize and disseminate among humans and environmental sources coupled with its ability to develop resistance to antimicrobial agents. Materials and Methods: Clinical isolates of Acinetobacter recovered from routine samples of inpatients were analyzed retrospectively along with their antibiogram to evaluate in vitro activity of Doxycycline. Multiple antibiotic resistance index was calculated and interpreted. Results: Out of 93 isolates of Acinetobacter species recovered, predominant were from urine 47(50.54%) and blood 27(29.03%) samples. MDR isolates were 57(61. 29%).Overall antimicrobial susceptibility pattern revealed best spectrum of activity with Imipenem (75.27%), Meropenem (68.82%) and Doxycycline (68.82%) whereas in MDR isolates Doxycycline exhibited highest sensitivity (66.67%) followed by Imipenem (61.40%) and Meropenem (52.63%). MAR indexes for different isolates revealed 71 (76.34%) with MAR index greater than 0.2 and 22 (23.66%) less than 0.2. However, three isolates had shown MAR index of 01 (i.e. resistant to all the antimicrobials tested), out of which two were recovered from intensive care unit and one from general surgery ward. Twenty-six MDR patterns were observed with nine antimicrobials tested. Resistance to COT, CIP, GEN, AK, A/S, CPM, IMP, MRP (R8) was most frequently observed pattern in 8(14.04%) of MDR isolates. Conclusion: Doxycycline has exhibited efficacy against MDR Acinetobacter, which can be considered as an alternative therapy to down regulate selective pressure on carbapenems. To confront the immediate threat of Acinetobacter infections, a working antibiotic strategy should be addressed and stringent infection control practices are needed to prevent the spread of multi drug resistant isolates in the hospital. Keywords: Acinetobacter species, Doxycycline, MAR index