Community-Acquired Pneumonia and Empyema Caused by Citrobacter koseri in an Immunocompetent Patient

Area of Science:

• Medical Microbiology
• Infectious Diseases
• Pulmonology

Background:

• Citrobacter species are environmental Enterobacteriaceae found in various ecological niches.
• Citrobacter koseri typically causes severe infections like septicemia and meningitis in neonates and immunocompromised individuals.
• Citrobacter infections present treatment challenges due to rapid antibiotic resistance and historically high mortality rates.

Purpose of the Study:

• To document and describe a rare case of community-acquired pneumonia and empyema caused by Citrobacter koseri.
• To highlight the occurrence of this infection in an immunocompetent adult, challenging previous assumptions about host susceptibility.
• To contribute to the understanding of the clinical spectrum of Citrobacter koseri.

Main Methods:

• Case report detailing clinical presentation, diagnostic workup, and treatment of an adult patient.
• Microbiological identification and characterization of Citrobacter koseri from clinical samples.
• Review of relevant literature on Citrobacter koseri infections.

Main Results:

• Successful treatment of community-acquired pneumonia and empyema caused by Citrobacter koseri in an immunocompetent adult.
• Demonstration of Citrobacter koseri as a causative agent in a non-neonatal, non-immunocompromised host.
• The patient recovered without long-term sequelae.

Conclusions:

• Citrobacter koseri can cause severe pulmonary infections, including pneumonia and empyema, in immunocompetent adults.
• This case expands the recognized clinical manifestations and host range for Citrobacter koseri infections.
• Further surveillance and research are warranted to understand the epidemiology and treatment of Citrobacter koseri in diverse patient populations.