Klebsiella ozaenae : Introduction, Morphology, Pathogenicity, Lab

Introduction of Klebsiella ozaenae

Table of Contents

Klebsiella pneumoniae subspecies ozaenae (Klebsiella ozaenae) is a Gram-negative bacterium (GNB), primarily associated with atrophic rhinitis (ozena), a chronic condition of the nasal cavity characterized by tissue thinning and unpleasant odor. It is also known as a normal inhabitant of the oral and nasopharyngeal mucosa. While often considered a colonizer, it can cause pneumonia, lung abscess, and urinary tract infections (UTIs).

Morphology of Klebsiella ozaenae

Fig. Klebsiella ozaenae colony morphology on CLED agar

The morphology of this bacterium is as follows-

Shape: Rod-shaped.
Size: 1-3 μm long and 0.5-1 μm wide.
Arrangement: Single, in pairs, or short chains.
Gram Stain: Gram-negative.
Motility: Non-motile.
Spore formation: Non-spore-forming.
Capsule: Prominent polysaccharide capsule.

Pathogenicity of Klebsiella ozaenae

Ozena: Klebsiella ozaenae is a key causative agent of ozena, a condition marked by chronic inflammation and atrophy of the nasal mucosa, leading to characteristic symptoms like nasal crusts, foul odor, and nasal obstruction.

Other Infections: Beyond ozena, it has been implicated in a range of other infections, including:

Urinary tract infections: Klebsiella ozaenae is a common cause of urinary tract infections.
Respiratory tract infections: They can cause pneumonia, sinusitis, and other respiratory infections.
Bacterial Meningitis: While less frequent, Klebsiella ozaenae has also been reported as an etiological agent of bacterial meningitis, especially in individuals with pre-existing conditions like diabetes.

Lab Diagnosis

Specimen Collection:

Nasal Swabs: For suspected cases of atrophic rhinitis (ozena).
Sputum: In cases of respiratory tract infections.
Blood: For suspected bacteremia.
Other: Urine, wounds, or other clinical specimens, depending on the suspected infection site. Gram Stain:

Gram Stain:

Gram-negative bacilli, often short and plump, may be observed.
Capsules, if present, will appear as clear spaces around the bacteria.

Culture

Media: Blood agar and MacConkey agar are commonly used.
Incubation: Aerobic incubation at 37°C.
Colony Morphology: Blood agar: Mucoid, non-hemolytic colonies. MacConkey agar: Mucoid, lactose-fermenting (pink) colonies.

Biochemical Testing

After obtaining pure cultures, biochemical tests differentiate Klebsiella ozaenae from other Klebsiella species.
Examples include tests for utilization of specific substrates, such as m-hydroxybenzoic acid, trans-hydroxy-l-proline, and histamine.

Molecular Methods (PCR)

PCR analysis can provide faster and more accurate identification of Klebsiella ozaenae, especially when combined with other identification methods.

Treatment

Klebsiella ozaenae infections are typically treated with antibiotics, though resistance is a growing concern. Systemic antibiotics, like ciprofloxacin, rifampicin, and trimethoprim-sulfamethoxazole, are commonly used. Treatment durations usually range from 2 to 3 months, or even longer in some cases.

Specifics:

Antibiotics: Ciprofloxacin, rifampicin, and trimethoprim-sulfamethoxazole are frequently used.
Treatment Duration: A 2–3-month course of antibiotics is often recommended. Some studies suggest longer durations, even up to 4 months, or even up to 74 months in some cases.
Adjuvant Therapies: In addition to antibiotics, other treatments like vitamin A, iron, potassium iodide, and estrogen have been explored with encouraging results.
Nasal Douching: Regular nasal douching is also recommended to improve nasal obstruction and prevent secondary infections.
Surgical Options: In some cases, surgical interventions, such as recalibration surgery with subperiosteal grafts, may be considered.

Prevention

To prevent Klebsiella ozaenae infections, focus on maintaining good hygiene practices, especially in healthcare settings. This includes frequent handwashing, proper cleaning of surfaces, and using single-use devices when possible. Private rooms or cohorting patients with the same infection, along with strict adherence to hand hygiene guidelines, are also crucial.

Here are some more detailed preventive strategies as follows-

1. Hand Hygiene:

Wash hands frequently: Wash hands with soap and water or use alcohol-based hand sanitizers after contact with infected patients, before and after touching surfaces, and after any activity that could lead to contamination.
Proper handwashing technique: Ensure hands are wet, lather with soap for at least 20 seconds, and thoroughly rinse and dry.

2. Environmental Control:

Cleaning and disinfection: Regularly clean and disinfect high-touch surfaces in healthcare settings, such as bed rails, bedside tables, doorknobs, and phones.
Use of single-use devices: Consider using single-use devices to minimize transmission from contaminated equipment.
Private rooms or cohorting: Isolate patients with Klebsiella infections in private rooms or, if necessary, cohort them with other patients with the same infection.

Prevention: Klebsiella ozaenae, a weakly pathogenic bacterium, is typically found in the normal flora of the upper respiratory passages. While it can be associated with chronic atrophic rhinitis, it can also cause serious infections like meningitis, bacteremia, and even fatal conditions.

keynotes of Klebsiella ozaenae:

Normal Flora and Pathogenicity:

Normal flora: K. ozaenae is part of the normal bacterial flora of the upper respiratory tract.
Weakly pathogenic: It is considered weakly pathogenic, meaning it usually doesn’t cause serious illness in healthy individuals.
Potential pathogen: Despite being part of the normal flora, K. ozaenae can cause infections in certain individuals, particularly those with compromised immune systems or pre-existing conditions.

Infections Associated with K. ozaenae:

Atrophic rhinitis: It is the putative cause of chronic atrophic rhinitis, a rare ENT disease.
Serious infections: K. ozaenae has been reported to cause life-threatening infections, including:
Meningitis: Cases of K. ozaenae meningitis have been reported.
Bacteremia: Presence of bacteria in the bloodstream.
Abscess formation: Can lead to abscesses in various organs, such as the brain, lungs, prostate, and kidneys.
Other serious infections: Sepsis, pneumonia, and other serious infections have also been reported.

Risk Factors:

Chronic rhinitis: Individuals with chronic rhinitis may be at higher risk.
Pre-existing conditions: Conditions like old age, prior antibiotic usage, immunosuppression, malignancy, alcohol abuse, and diabetes mellitus can increase the risk of K. ozaenae infections.
Compromised immune systems: Individuals with weakened immune systems are more susceptible to infections caused by K. ozaenae.

Klebsiella ozaenae : Introduction, Morphology, Pathogenicity, Lab Diagnosis, Treatment, Prevention, and Keynotes