**1. Introduction**

*Pseudomonas* happens to be one of the most studied genera of prokaryotes (bacteria) and was first identified by Migula in 1894 at the end of the nineteenth century and described as Gram-negative, polar-flagellated, and rod-shaped bacteria. Thereafter the time of identification, the description of *Pseudomonas* has broadened; new methods have been developed to enhance the comprehensive study of the morphology and physiology of *Pseudomonas*. It is worthy to mention that the morphological features of these bacteria are common to several bacteria genera and are of little value in the positive identification of members of the genus (*Pseudomonas*). There are advanced nucleic acid-based methods that easily differentiate these bacteria from other similar genera, thus revealing the taxonomic relationships among various bacterial species including the genera *Pseudomonas*.

*Pseudomonas* is known to occupy a wide range of niches due to metabolic and physiological array. Their diversity enables *Pseudomonas* to adjust to exigent

environmental conditions and withstand unfavorable conditions caused as a result of living and nonliving factors like oxygen, moisture, high and low temperature, etc.

The diversity of *Pseudomonas* determines wide research interest in this genus (*Pseudomonas*). *Pseudomonas aeruginosa* is ubiquitous in the environment (soil and water) and flourishes in individual with weakened or compromised immune system. The increasing resistance to multiple antibiotics makes these bacteria (*Pseudomonas aeruginosa*) virtually intractable once it colonizes the human host, and devastating effects can manifest.

Other species of *Pseudomonas aeruginosa* have the ability to degrade a large number of compounds that are recalcitrant to other bacterial species, thus producing secondary metabolites and biopolymers, making these strains useful in medicine, industries, and environment [1].
