[Structural elements of Pseudomonas aeruginosa based on electron microscopy findings]

Area of Science:

• Microbiology
• Bacteriology
• Microscopy

Background:

• Pseudomonas aeruginosa (Ps. aeruginosa) is a significant opportunistic pathogen.
• Understanding bacterial morphology is crucial for identification and classification.
• Flagellar arrangement and presence can be distinguishing characteristics in bacterial taxonomy.

Purpose of the Study:

• To investigate the potential of using flagellar number and location for identifying Pseudomonas aeruginosa.
• To characterize the morphological variations within Ps. aeruginosa strains regarding flagella and pili.

Main Methods:

• Negatively contrasted preparations of bacteria were examined using electron microscopy (JEM-100).
• A total of 4,800 Ps. aeruginosa cells were analyzed for flagellar and pili presence and arrangement.
• Morphological variations including flagellar count, polar vs. bipolar location, and presence of pili were documented.

Main Results:

• Out of 4,800 bacteria, 2,443 had a single polar flagellum, 414 had two, and 138 had three polar flagella.
• A significant number (1,805) of cells were found to be nonflagellate.
• The study also revealed the presence of bipolar flagella, pili, and the coexistence of capsular and noncapsular forms within the same Ps. aeruginosa strain.

Conclusions:

• Flagellar morphology in Ps. aeruginosa is more diverse than previously assumed, including nonflagellate and bipolar flagellated forms.
• The presence of both capsular and noncapsular forms in a single strain suggests phenotypic plasticity.
• These findings may contribute to refining the systematics and identification methods for Pseudomonas aeruginosa.