Background:

Majority of gram negative bacterias have developed resistance and are multidrug resistant which increased the mortality rate. In the current era when there is higher rate of multidrug resistance there is a need to review all the antibiotics which were previously used. Recent literature found a promising effect of colistin against multidrug resistant so the current study aimed to find out the in vitro activity of colistin in comparison with other antibiotics against gram negative bacteria.

Methods: 

A Quasi experimental study was conducted in department of Pharmacology, Ziauddin University. Sample from pus, wound swab, blood, urine and from endotracheal secretion were collected. Samples were cultured on Blood agar and MacConkey Agar. Antibiotic susceptibility testing done by Kirby Bauer Disc diffusion technique using Mueller Hinton Agar plate. Agar dilution method was used to find the minimum inhibitory concentration (MIC). Data was analyzed by using Statistical Package for Social Sciences (SPSS) version 21. P value of less than 0.05 was considered as significant.

Results:

The mean age of study participants was 54 ± 20 years. About 176 strains of gram negative bacteria were tested, out of which 79 strains were multidrug resistant while 97 strains were of non-multidrug resistant gram negative bacteria. Colistin showed good in-vitro activity against many strains of the multidrug resistant gram negative bacilli as it was 100% sensitive against Acinetobacter and E.coli with zero resistance. Colistin was also very effective against pseudomonas aeruginosa and klebsiella pneumonia with sensitivity of 99% and 94% respectively. Only the enterobacter, among all MDR strains showed 75% sensitivity with 25% resistance.

Conclusion:

It can be concluded that colistin is highly sensitive against multidrug resistant gram negative bacilli including Acinetobacter, E.coli, Pseudomonas aeruginosa and klebsiella pneumonia with little or no resistance in comparison to other antibiotics.

Keywords: Gram negative bacilli, Multidrug resistant, Colistin