Heavy metals resistance of pseudomonas aeruginosa isolated from clinical and environmental sources in Hilla City

Abstract EN

The study included 300 samples collected from 150 clinical and 150 hospital environmental sources.

Only 43 (14.3 %) isolates belonged to Ps.

aeruginosa.

The isolates tested for detection of their susceptibility for 7 types of heavy metals (HM) included (Copper Sulfate, Silver Sulfate, Mercury chloride, Lead nitrate, Zinc sulfate, Cadmium sulfate, and Nickel sulfate).

The screening tests for all isolates were detected using Lead nitrate in concentration of (400μg / ml).

Results revealed that 37 : 43 were resistant to lead nitrate (400μg / ml) ; this results may due to the Pseudomonads have P-type ATPase that can resist pb2+.

The minimum inhibitory concentration (MIC) of 7 HM was detected by agar dilution method and pouring method.

Results revealed that number of isolates were resistant to 7 HM in some of concentrations due to complex enzymes, active efflux, and operon that reduced toxic.

The plasmid content investigated for all 37 isolates of Ps.

aeruginosa (34 clinical and 3 environmental); Results revealed that most isolates 32 : 37 harbored large (mega) plasmid.

The biofilm production of Ps.

aeruginosa isolates was investigated.

Results showed that 20:43 (47 %) of isolates had biofilm.

This study concluded that the increase of HM resistance was correlated with biofilm production for some HM used.

The bacterial curing is proceeding for one isolate Ps.

aeruginosa (Ps.3).

The results showed survived resistance to all HM used, may be due to HM resistance trait was carried out on bacterial chromosome rather than plasmid.