Evaluation of Tigecycline and Minocycline Susceptibility among Clinical Isolates of Carbapenem Resistant Acinetobacter Species

BACKGROUND Acinetobacter species are important infectious agents worldwide especially in healthcare settings. It has the ability to develop various resistance mechanisms to various antibiotics. We wanted to study the role of tigecycline and minocycline in the treatment of multidrug resistant Acinetobacter species. METHODS 254 non-repetitive isolates of Acinetobacter species from various clinical samples like exudates, blood, sputum, urine were retrospectively studied. Antibiotic susceptibility testing was done by Vitek 2 compact system. Susceptibility of the carbapenem resistant isolates towards tigecycline and minocycline were analysed. RESULTS 205 (80.7 %) isolates were resistant to either of the carbapenem drugs and 49 (19.3 %) were sensitive to all the 3 carbapenems, namely imipenem, meropenem and doripenem. 54.1 % isolates were sensitive to tigecycline while sensitivity towards minocycline was 40.5 %. The degree of sensitive concordance in the susceptibility to minocycline and tigecycline against Acinetobacter species was 31.1 %, which indicated fair agreement statistically. 21.1 % isolates were resistant / intermediate to minocycline but sensitive to tigecycline. Only 9.4 % isolates which were resistant to tigecycline were sensitive to minocycline. CONCLUSIONS The results of the present study have demonstrated that minocycline and tigecycline are effective against the carbapenem resistant Acinetobacter species. Tigecycline can be considered as a therapeutic agent for the treatment of multidrug resistant Acinetobacter which are otherwise difficult to inhibit using other antibiotics. KEY WORDS Carbapenem Resistance, Tigecycline, Minocycline, Antimicrobial Resistance