Citrobacter koseri Pneumonia As Initial Presentation of Underlying Pulmonary Adenocarcinoma

Area of Science:

• Medical Microbiology
• Infectious Diseases
• Pulmonology

Background:

• Citrobacter koseri is a gram-negative bacterium known for causing infections, particularly in immunocompromised individuals or those with comorbidities.
• While nosocomial infections are common, community-acquired C. koseri infections are rare.
• The bacterium is a motile, gram-negative rod.

Observation:

• A previously healthy male patient in his 60s presented with pneumonia caused by Citrobacter koseri.
• This presentation is unusual given the patient's lack of significant comorbidities or known immunocompromised status.

Findings:

• The Citrobacter koseri pneumonia in this patient was found to be associated with an underlying pulmonary adenocarcinoma.
• This association suggests a potential link between intrapulmonary pathology and C. koseri infection.

Implications:

• This case underscores the necessity of thorough investigation for underlying immunodeficiency and intrapulmonary pathology in patients presenting with C. koseri infections, even if they appear healthy.
• Further research may elucidate the relationship between specific cancers and susceptibility to certain bacterial infections.
• Diagnostic and treatment protocols for C. koseri infections may need to consider the possibility of underlying malignancy.