AN IN-VITRO STUDY OF TIGECYCLINE SUSCEPTIBILITY AMONG MULTIDRUG RESISTANT BACTERIA IN A TERTIARY CARE HOSPITAL

Background & objectives: Emergence and spread of antibiotic resistance among bacteria pose a challenge to clinicians due to limited therapeutic options available. Multi drug resistant (MDR) bacteria are known to cause life threatening infections in intensive care settings. Tigecycline is a newer glycycline antibiotic, considered as therapeutic option for MDR gram positive and gram negative bacteria. Aim of this study was to evaluate in-vitro susceptibility of tigecycline in MDR bacteria. Methods: We studied the in-vitro activity of tigecycline in 100 MDR bacteria isolated from blood, skin, soft tissue and surgical site infections, urine, sputum, bronchoalveolar lavage, CSF and other body fluids of patients admitted to a tertiary care hospital in South India. MDR bacteria tested for tigecycline susceptibility by disc diffusion and E-test included: Methicillin resistant S.aureus (MRSA) (35), extended spectrum β lactamase (ESBL) producing Enterobacteriaceae (36), P.aeruginosa (15) and Acinetobacter spp. (14). Results: Tigecycline was found effective against all isolates of MRSA (MIC90 ≤0.25μgm/ml). All ESBL producing E.coli, Klebsiella and Enterobacter isolates were susceptible (MIC90 ≤1.0μgm/ml). However MDR isolates of Acinetobacter spps. showed reduced susceptibility to tigecycline (64.28% sensitive) with MIC90 of 2.0μgm/ml. 86.66% P.aeruginosa isolates were resistant to tigecycline. Interpretation & conclusions: This study shows that tigecycline can be a useful reserve antibiotic against MDR MRSA and ESBL producing Enterobacteriaceae, but a higher prevalence of resistance is seen among members of Acinetobacter spp and P.aeruginosa. Clinicians should however look out for adverse effects associated with tigecycline such as acute pancreatitis, severe nausea, vomiting and septic shock.