Tigecycline in-vitro susceptibility and antibiotics’ fitness for gram-negative pathogens

Objectives: To determine the tigecycline in-vitro susceptibility of naive gram-negative pathogens from serious infections in Delhi, India.Methods: During July to October 2007 investigations were carried out to determine the tigecycline in vitro susceptibility of 50 consecutive gram-negative pathogens from serious infections at the Sant Parmanand Hospital, Delhi, India. Minimum tigecycline inhibitory concentrations were determined employing the E test method (AB Biodisk). Results: Twenty-four percent of isolates were found to be tigecycline resistant or partly susceptible. Susceptibility of the isolates was lower than meropenem but similar to piperacillin-tazobactam, amoxicillin-clavulanic acid, and amikacin.Conclusion: Tigecycline resistance was prevalent in the gram-negative isolates from serious infections prior to its marketing in India. The choice of any recently marketed antibiotic for a pilot treatment against serious gram-negative infections should not be automatic. In the initial phase of its marketing, it should be evaluated in parallel with the antibiotics with excellent local susceptibility profiles.