A Comprehensive Review of Klebsiella Species and Their Medical Significance

Introduction klebsiella species

A group of bacteria that normally lives in the intestinal tract, but can cause infections when the microorganisms infects tissues of body. Klebsiella are frequently the cause of infections acquired in hospitals.  Found in the digestive and respiratory systems of humans, large capsule, protects against phagocytosis and antibiotics and makes the colonies moist and mucoid. The major virulence factor Over 70 capsular types have been defined. Pili adherence to respiratory and urinary epithelium Non-motile, Cause opportunistic infections, frequent cause of nosocomial pneumonia. Of all the Enterobacteriaceae, Klebsiella species are now among the most resistant to antibiotics.

Klebsiella Species

1. Klebsiella pneumoniae:

K .pneumoniae: present in the respiratory tract and feces of about 5% of normal individuals. Cause pneumonias, UTI and bacteremia with focal lesions in debilitated patients, meningitis, and wound infections. Capsule stain: is a negative staining technique used to visualize bacterial capsules. In this method, the background is stained, leaving the capsule clear and colorless, which forms a halo around the stained bacterial cell. This technique is essential in identifying encapsulated bacteria in clinical samples, as it helps distinguish encapsulated strains from non-encapsulated ones. The ability to visualize the capsule is important because it can indicate the virulence of the bacteria with encapsulated strains often being more pathogenic. Capsules are protective polysaccharide layer surrounding some bacteria which plays a critical role in bacterial survival and pathogenicity. Klebsiella pneumoniae can Couse: sepsis, pneumonia, and urinary tract infections.

Clinical findings

Urinary tract infections: pyelonephritis and cystitis in catheterized patients. Pneumonia In debilitated patients with K. pneumoniae infection, the K. pneumoniae strains are typically resistant to many drugs and generally cause severe disease. Even with appropriate therapy, the fatality rate of pneumonia due to K. pneumoniae is 40-60 %. Rhinitis: Infection of the nasal epithelium with K. ozaenae can lead to atrophic rhinitis. Infection with K. ozaenae can also cause ozena, a rare form of suppurative rhinitis in which a foul smelling greenish exudate obstructs the nasal passages. Rhinoscleroma: That is caused by K. rhinoscleromatis begins with symptoms resembling those of an ordinary cold. Granulomatous inflammation of the nasal airway leads to development of tumor like submucosal masses. The masses can become quite large and may close the nares and cause the face to swell. Rhinoscleroma, simply Scleroma

Prognosis & treatment it is not lethal in nature and is responsive to Tetracycline or Ciprofloxacin. However, if left untreated the disease can lead to sepsis, hemorrhage or other

Chronic conditions that can be fatal.

2. Klebsiella oxytoca:

A species of gram-negative bacteria causing urinary tract infections and septicemia. Klebsiella oxytoca is gram-negative, rod-shaped bacterium closely related to bklebsiella pneumoniae. While it is part of the normal flora in the human intestines, mouth, and nose, it can cause serious infections when it spreads to other parts of the body, particularly in healthcare settings. Pathogenicity: it is an opportunistic pathogen that can cause infections such as pneumonia, urinary tract infections, wound infections, and sepsis. It ia also associated with antibiotic-associated hemorrhagic colitis. Virulence factors: like K. pneumoniae, it has a polysaccharide capsule that enhances its ability to evade the immune system. It is also capable of acquiring antibiotic resistance, including extended-spectrum beta-lactamases and carbapenemases.

Haw to diagnosis klebsiella species

• Specimen: Sputum, urine, pus, CSF, body fluid.

• Smear: Gram-negative rods.

• Culture: Large, mucoid, lactose-fermenting colonies on mac conkey agar, and shows stringy type growth when cultured in broth medium.

• Serology: Capsular polysaccharide serotyping. More than 80 serotypes of K. pneumoniae recognized.

Treatment of klebsiella

Since isolates from hospital -acquired infection are frequently resistant to multiple antibiotics, the choice of drugs depends on results of sensitivity testing. However, gentamycin and Cefotaxime can be used.

Prevention 

Removing of urinary catheters when they are no longer needed. Taking proper care of respiratory therapy devices.

Conclusion

Klebsiella is an important opportunistic pathogen that belongs to the Enterobacteriaceae family. It is commonly found in the human gastrointestinal tract but can cause serious infections such as pneumonia, urinary tract infections, septicemia, and wound infections, especially in immunocompromised individuals. Its ability to produce a protective capsule and develop resistance to multiple antibiotics makes it a significant public health concern. Effective infection control measures, proper hygiene, and rational use of antibiotics are essential to prevent and manage Klebsiella infections.