Unmasking the silent invader: A rare encounter of Neisseria gonorrhoeae in joint fluid.

To the Editor A 36-year-old male patient presented to the hospital with pain and swelling in his left knee. His examination revealed hemoglobin levels of 11.9 g/dL, red blood cell (RBC) counts of 3.64 10/μL, white blood cell (WBC) counts of 17 10/μL and platelet counts of 673 10/μL. The serum levels of alanine aminotransferase were higher than the normal range at 59 IU/L (reference range: 7–52 IU/L). The erythrocyte sedimentation rate (ESR) value obtained was significantly elevated at over 140 mm/h (reference range: 0–15 mm/h). The patient presented with a 4-day history of pain, effusion, and swelling in the left knee. The affected joint was warm to the touch and exhibited signs of inflammation during the physical examination, such as erythema and joint effusion. During a focused sexual history interview, the patient disclosed that they had engaged in sexual activity with multiple partners without using protection approximately a month ago. Microscopic examination of the synovial fluid revealed a markedly elevated count of RBCs and total nucleated cells, with a predominance of neutrophils. These findings were further supported by the presence of elevated inflammatory markers, including significantly increased levels of WBC and ESR. Additional investigations, such as microbiological cultures, were performed on the synovial fluid. The culture plates were incubated in a humidified atmosphere with 5%–10% carbon dioxide at a temperature of 35–37 C for 24–48 h. Microbiological cultures were performed on the synovial fluid, and subsequent cultures revealed the growth of small, grayish, translucent colonies on chocolate agar (Figure 1A). The Gram stain of the clinical specimen revealed the presence of Neisseria gonorrhoeae. The findings showed characteristic