Makindo Medical Notes

Related Subjects: Asthma |Acute Severe Asthma |Exacerbation of COPD |Pulmonary Embolism |Cardiogenic Pulmonary Oedema |Pneumothorax |Tension Pneumothorax |Respiratory (Chest) infections Pneumonia |Fat embolism |Hyperventilation Syndrome |ARDS |Respiratory Failure |Diabetic Ketoacidosis

Klebsiella pneumoniae is a leading cause of hospital-acquired pneumonia in the United States. Antibiotic resistance, including carbapenem resistance, is a critical issue with this pathogen.

About

• Originally known as Friedländer's bacillus, Klebsiella is a significant gram-negative pathogen.
• It is a lactose-fermenting member of the Enterobacteriaceae family.
• The large polysaccharide capsule is the primary virulence factor, offering protection against phagocytosis.
• Klebsiella strains lacking a capsule are considerably less virulent.

Source

• Commonly found in the human gastrointestinal tract and oropharynx as part of normal flora but may spread to the respiratory and urinary tracts.
• Its high virulence and antibiotic resistance make it a major threat in hospital and healthcare settings.

Characteristics

• Gram-negative, encapsulated rods
• Aerobic and facultative anaerobe
• Glucose fermenting, oxidase-negative, and catalase-positive
• Reduces nitrates to nitrites
• Ferments lactose, forming pink colonies on MacConkey agar

Clinical Presentation

• Symptoms: Fever, dyspnoea, cough with "currant jelly" sputum, consolidation on imaging, and sepsis.
• High-Risk Groups: Alcoholics, diabetics, and patients on ventilators or with underlying lung disease.

Pathogenicity

• Pneumonia: Typically presents as a severe lobar pneumonia with thick, bloody (currant jelly) sputum. Commonly affects those with compromised lung function or alcohol use disorder.
• Urinary Tract Infections (UTIs): Particularly common in patients with long-term catheter use or diabetes.
• Pyogenic Liver Abscess: An invasive form associated with bacteremia, especially seen in individuals with diabetes or chronic illness.

Resistance

• Beta-lactamase production: Many Klebsiella strains produce extended-spectrum beta-lactamases (ESBLs) that hydrolyze beta-lactam antibiotics.
• Carbapenem resistance: Some strains have developed resistance to carbapenems, complicating treatment.
• Multidrug resistance: Resistance to aminoglycosides, fluoroquinolones, and other antibiotics is also increasingly common.

Management

• Supportive Care: Airway management, oxygen supplementation, chest physiotherapy, and HDU/ICU support if required.
• Antibiotics: Consult microbiology for optimal therapy, as resistance patterns can vary widely. Regimens may include:
  • For non-resistant strains: Third-generation cephalosporins (e.g., ceftriaxone), fluoroquinolones, or aminoglycosides.
  • For ESBL-producing strains: Carbapenems may be effective but are limited by the rise of carbapenem resistance.
  • For carbapenem-resistant strains: Combination therapy may be necessary, including agents like colistin, tigecycline, or fosfomycin.
• Prognosis: Mortality remains high (30-50%) even with treatment, especially among elderly, diabetic, or immunocompromised patients.