BACKGROUND: Brain abscess is a serious and potentially fatal disease caused primarily by microbial infection. Although progress has been made in the diagnosis and treatment of brain abscesses, the diagnostic timeliness of pathogens needs to be improved.
METHODS: We report the case of a 54-year-old male with a brain abscess caused by oral bacteria. The patient recovered well after receiving a combination of metagenomic next-generation sequencing (mNGS)-assisted guided medication and surgery.
CONCLUSIONS: Therefore, mNGS may be widely applied to identify the pathogenic microorganisms of brain abscesses and guide precision medicine.

Pigmented purpuric dermatosis is a rare, unique purpuric skin disorder, most commonly located on the lower extremities and characterized by petechiae with tiny red rashes and brown pigmented patches. The precise etiology and a reliable treatment have not been established. This case report presents a 72-year-old female with repeating purpuric, tiny rashes and persistent extensive brown pigmented patches with pigmented purpuric dermatosis on both lower extremities for the past 20 years. Ozone nanobubble (ONB) water is a new sterilizing agent containing dissolved nanosized ozone gas bubbles in water. The patient performed an oral rinse every night with ONB water and was successfully treated. However, vitamin C administration and Ruby laser treatment were needed to reduce residual pigmentation. This case suggests that oral bacteria may be a causative factor of pigmented purpuric dermatosis.

Neither the etiology nor a reliable treatment for palmoplantar pustulosis has been clearly established. Ozone nanobubble (ONB) water, which is treated with nanosized ozone gas particles and has strong antimicrobial activity, has attracted attention as a future therapeutic option for palmoplantar pustulosis. Oral rinsing, particularly in the periodontal areas, with 10 to 20 mL ONB water for a couple of minutes per night, was prescribed to seven palmoplantar pustulosis patients, comprising five female and two male patients, for 6 months. Skin lesions were observed to be completely cured within a treatment period of approximately 3 to 4 months in six patients; the exception case was the one suspected of having pyorrhea. Rinsing the periodontal area with ONB water resulted in very effective suppression of skin lesions and showed promise as a new treatment method for palmoplantar pustulosis, which suggested the involvement of oral bacteria.

The risk of periprosthetic joint infection from hematogenous bacterial seeding is increased in patients undergoing dental procedures that facilitate the development of bacteremia. We herein report the case of a patient without a history of dental procedures who suffered from an acute metastatic infection of a hip prosthesis by the oral bacterium Streptococcus mutans 18 months after undergoing revision total hip arthroplasty. The patient was successfully treated by two-stage revision surgery. It is important to realize that the efficacy of antibiotic prophylaxis against joint infections has not yet been convincingly proven. As a result, optimal dental hygiene and regular dental visits may be more important than antibiotic prophylaxis for maintaining joint health. Therefore, orthopedic surgeons should educate patients with joint prostheses about good oral health.