The in Vitro Activity of Tigecycline Against the Multidrug Resistant Acinetobacter Spp. at a Tertiary Care Hospital
Dr. Dipender Kaur Najotra,
Senior Resident, Department of Microbiology,
207-D uttam nagar Kunjwani Bye- pass, jammu,
Jammu and Kashmir, Pin code- 180010, India.
Background: The Acinetobacter spp., particularly A.baumanii, has emerged as one of the most troublesome pathogens in health care institutions globally, because they are often Multi Drug Resistant (MDR), which means that the therapy and the infection control are complicated. With the emergence of the carbapenemase-producing isolates which show resistance to all the available agents except the polymyxins, this genus deserves close attention. In this scenario, tigecycline, a glycylcycline which has a spectrum of activity which is unparalleled by any other broad spectrum agent, and is not affected by most of the known mechanisms of resistance to tetracycline which have been encountered in bacteria, is a useful alternative for the treatment of the infections which are caused by the Acinetobacter spp.
Aim: This study was conducted to investigate the in vitro activity of tigecycline against a collection of MDR isolates of Acinetobacter spp. from our hospital.
Material and Methods: A prospective, hospital based study was conducted from October 2010 to April 2012 in which all the Acinetobacter spp. isolates which were obtained from clinical samples, were subjected to the testing of their antimicrobial susceptibilities to different groups of drugs, which included tigecycline. Based on the susceptibility profile, the isolates which were labeled as MDR were further subjected to the Epsilometer test (E-test) to determine the minimum inhibitory concentrations (MIC) of tigecycline.
Results: A total of 85 Acinetobacter spp. isolates were obtained, out of which 38 (44.7%) were labeled as MDR. 91.8% of the total and 81.5% of the MDR isolates were sensitive to tigecycline and the MICs of tigecycline for these MDR isolates ranged from 0.25 to 32 μg/ml.
Conclusion: This study proved that tigecycline exhibited a good in vitro activity against the clinical isolates of the MDR Acinetobacter spp., and that it may be considered as a promising therapeutic option for the treatment of the nosocomial infections which were caused by these pathogens. But the tigecycline resistance among the isolates that had not previously been exposed to the drug is worrisome. So before starting the treatment, the in vitro susceptibility of the isolates to tigecycline and its MIC should be assessed.