Bartonella henselae is usually not viable in lymph nodes of patients with cat scratch disease

Area of Science:

• Infectious Diseases
• Microbiology
• Pathology

Background:

• Bartonella henselae is the primary cause of cat scratch disease (CSD), a common condition leading to lymphadenitis in children and adults.
• Isolation rates of B. henselae from CSD patient lymph nodes are notably low, suggesting challenges in detecting active infection.

Purpose of the Study:

• To assess the viability of Bartonella henselae within lymph node biopsy samples from patients diagnosed with CSD.
• To investigate the discrepancy between the presence of B. henselae DNA and active bacterial presence in CSD lymphadenitis.

Main Methods:

• Analysis of 87 lymph node biopsy samples from CSD patients using reverse transcription-quantitative polymerase chain reaction (RT-qPCR) to detect B. henselae RNA.
• Complementary diagnostic methods included bacterial cultures, histological analysis, and fluorescence in situ hybridization (FISH).

Main Results:

• Only 8% (9 out of 87) of lymph nodes positive for B. henselae DNA also showed detectable B. henselae RNA, indicating low viability.
• No significant difference in threshold cycle (CT) values was observed between RNA-positive and RNA-negative samples.
• Cultures, histology, and FISH assays were negative across all tested samples, further supporting limited bacterial viability.

Conclusions:

• Bartonella henselae demonstrates limited or no viability in the majority of lymph nodes from patients presenting with cat scratch disease.
• The presence of B. henselae DNA in lymph nodes does not reliably indicate active bacterial infection or viability in CSD cases.