Antimicrobial susceptibility pattern of clinical isolates of Pseudomonas aeruginosa isolated from patients of lower respiratory tract infections

The present study was conducted to determine the antibiotic susceptibility pattern of Pseudomonas aeruginosa from sputum samples of lower respiratory tract infection patients admitted to different hospitals of Karachi. Most of the hospitals are hampered with high frequency of nosocomial infections generally caused by multiresistant nosocomial pathogen. Among Gram-negative pathogens Pseudomonas aeruginosa considered as most challenging pathogen. The objective of the study was to determine frequency of Pseudomonas aeruginosa from sputum samples and to find out susceptibility pattern against four antibiotics widely used for treatment. The sputum samples from 498 patients were collected consecutively between January 2010 and March 2011 and were cultured and identified. According to CLSI (Clinical Laboratory Standards Institute) guidelines antimicrobial susceptibility testing was performed by disc diffusion method. Pseudomonas aeruginosa were isolated from 24% (120/498) of the lower respiratory tract patient. A higher resistance to Pseudomonas aeruginosa isolate was observed with piperacillin/tazobactam and cefipime i.e. 42% and 40% respectively. Imipenem was found to be most effective antibiotic against Pseudomonas aeruginosa (76% sensitivity) but amikacin resistance was continuously increasing. In conclusion the frequency of Pseudomonas aeruginosa was also higher among lower respiratory tract infection patients with alarmingly high rate of resistance among widely used antibiotics. These findings focused on careful consideration for monitoring and optimization of antimicrobial use in order to reduce occurrence and spread of antimicrobial resistant pathogen.