Journal of Pure and Applied MicrobiologyVol. 9 No. 2

Studies on Multiple Drug Resistance (MDR) among Pseudomonas aeruginosa Isolates and their Virulence Factors

Naveen Minhas, Bharti and P.C. Sharma

Department of Microbiology, School of Biotechnology, Shoolini University of Biotechnology and Management Sciences, Bajhol, Solan (H.P.), India.

Received on 12 September 2014 and accepted on 21 January 2015



MDR Pseudomonas aeruginosa strains have been isolated from clinical specimens with increasing frequency by various workers. The knowledge of prevalence of MDR isolates and screening of extended spectrum beta lactamase (ESBL) as mechanism of resistance and phenotypic expression of their virulence factors in the state of Himachal Pradesh is, therefore, essentially required. The aim of the study is to assess the prevalence of multidrug resistant isolates, extensive drug resistant (XDR), pan drug resistant isolates, ESBL producing isolates and to compare their virulence factors with those of sensitive strains. A total of 180 isolates recovered from patients at Indira Gandhi Medical College, Shimla were confirmed as P. aeruginosa isolates. These isolates were screened for their susceptibility to different antibiotics that are commonly used to treat infections due to this organism by in vitro antibiotic cultural sensitivity assay (Bauer, 1966). ESBL as a mechanism of resistance was confirmed by Double disc diffusion synergy test (DDST) and E test. Lipase, hemolysin, protease, gelatinase and biofilm formation were some of the virulence traits whose phenotypic expression in vitro was studied in respect of both MDR and MDS isolates. 27.22% (49/180) isolates of P. aeruginosa were recorded as MDR whereas 55% (99/180) as XDR and 1.11% (2/180) as PDR. Only 28.57% (16/56) ESBL producers were MDR also while rest 71.43% (40/56) ESBL producers were sensitive to multiple drugs. P. aeruginosa both resistant as well sensitive strains produced lipase, hemolysin, protease, gelatinase and biofilms. The proportions of strains expressing different virulence factors were comparable. The hospital based epidemiological data might have implications in better infection control as well as therapeutic strategies by virtue of the knowledge of antibiotic resistance patterns in this geographic region as well as prevalence of ESBL producers.

Keywords : Extensive drug resistant, Extended spectrum beta lactamase (ESBL), Multi drug resistant, Pan drug resistant, Pseudomonas aeruginosa, Virulence factors.