周囲への感染リスクを有するCOVID-19感染者を検出するために迅速抗原検査を用いたスクリーニングを行うことの妥当性の有無を知る目的で，COVID-19患者/疑い患者ならびに無症状の患者濃厚接触者から採取した鼻咽頭拭い検体の中で定量的リアルタイムRT-PCR検査でSARS-CoV-2遺伝子が検出された162検体について，ウイルス分離を試み分離陽性検体を101検体得た．また，これらの162検体について本邦で市販されていた5社5種類の簡易迅速抗原検出キット製品を用いた抗原検査を試みた．PCRで得られた検体中のウイルス遺伝子コピー数のデータとウイルス分離成績の結果をあわせ，用いた製品ごとに解析した．その結果，被験者の症状の有無にかかわらず，すべてが感染性ウイルスが分離された検体の95％以上に陽性を示し，このような検査対象集団においては迅速抗原検査に感染伝播リスクの見逃しが少ないことがわかった．

【背景】経口COVID-19治療薬であるパキロビッドパック（以下パキロビッド：ニルマトレルビル/リトナビル）は，各種薬物代謝酵素への影響の大きいリトナビル配合の薬剤であることから，併用薬との薬物相互作用が懸念されている．しかし実臨床での使用経験に関する報告は乏しい．

【方法】パキロビッドの薬物相互作用を簡便にチェックできるツールとして，併用に注意すべき薬剤リストと薬物相互作用検索ツールを整備した．また2022年2月15日から5月14日までの3カ月間で，パキロビッドを処方された患者33名を対象に併用薬との薬物相互作用に関する問い合わせ事例，薬剤師の提案内容と医師による採択件数を調査した．さらに，服薬開始後に行った患者フォローアップの一環として，一時中止すべき常用薬のあった外来患者に対して電話連絡を行い，服薬遵守状況，一時中止薬の再開時期等の確認を行った．

【結果】薬物相互作用に関する問い合わせは28件あり，薬剤師の提案に対する医師の採択率は100%であった．電話連絡は7名に実施され，そのうち1名は一時中止薬の再開時期に関して理解不十分であったため，電話連絡時に再度説明を行い，2回目の電話連絡で間違いなく再開できていることを確認した．

【考察】薬剤師は薬物相互作用マネジメントや患者フォローアップ等の業務を通じて，パキロビッドの円滑な処方及び適正使用に貢献できると考える．

An 86-year-old woman with a 6-year history of bronchiectasis and recurrent pneumonia in the right lung presented to our hospital with a several weeks' history of bloody sputum. Imaging studies showed ground-glass and infiltrative opacities in the right lung, and Nocardia species were repeatedly isolated on sputum culture testing. Genetic testing identified Nocardia wallacei, which was resistant to sulfamethoxazole/trimethoprim. Therefore, the patient was treated with clavulanic acid/amoxicillin (CVA/AMPC) for a total of 6 months, and the symptoms, including the bloody sputum and cough, as well as the imaging findings, improved. Pulmonary nocardiosis can occur in patients with chronic lung disorders such as bronchiectasis, even in the absence of immunodeficiencies. Trimethoprim-sulfamethoxazole is the drug of first choice for nocardiosis, but identification of the Nocardia species and susceptibility testing are recommended for treatment, because the susceptibility varies with the species.

We encountered a case of Candida kefyr fungemia with pyelonephritis. C. kefyr was first isolated from a dairy kefir in Caucasus in 1909 and was originally named Saccharomyces fragilis. C. kefyr has been reported to be detected in the urine and blood of immunocompromised patients and patients with hematologic malignancies. The patient reported herein, an 89-year-old woman, visited our hospital with the chief complaints of abdominal pain and fever. She was treated by ureteral stent placement and started on PIPC/TAZ for calculous pyelonephritis caused by K. pneumoniae. The clinical course was satisfactory, however, on the 15th day of hospitalization, she again developed lower abdominal pain, blood examination revealed increased levels of inflammatory markers, and C. kefyr was detected in blood and urine cultures. She was treated with L-AMB and FLCZ and discharged in good general condition. In recent years, the frequency of isolation of non-albicans Candida spp. has increased, and the incidence of C. kefyr candidemia has increased worldwide. A search of the literature to the best of my ability failed to identify the number of cases reported in Japan, and many uncertainties remain as to the epidemiology and drug susceptibility; therefore, further study of a larger number of cases is necessary in the future.

Mycobacterium chelonae is a rapidly growing nontuberculous mycobacterium and a rare cause of cutaneous infection in both immunocompromised and immunocompetent patients. The skin lesions are non-specific in nature, so that the infection remains underdiagnosed and diagnosis is often delayed. Herein, we report the case of an 83-year-old immunocompromised woman with a 6-month history of persistent skin lesions. The lesions were previously misdiagnosed and treated as herpes zoster, and even as bullous pemphigoid, for which she received prednisone. Ziehl-Neelsen staining of biopsy specimens from the subcutaneous nodules on the right forearm and dorsum of the left foot revealed acid-fast bacilli. Culture on blood agar medium under low-temperature conditions yielded colonies after 6 days. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry allowed identification of M. chelonae; the results were consistent with that of 16S rRNA gene sequencing analysis. Therefore, we made the diagnosis of disseminated cutaneous M. chelonae infection and initiated the patient on combined clarithromycin, moxifloxacin, and amikacin therapy. The findings in this case indicate that clinicians should consider mycobacterium-related infections in patients with intractable skin lesions. To obtain a proper microbiological diagnosis, good collaboration between clinicians and clinical laboratory technicians is necessary, with collection of appropriate specimens and use of appropriate stains and culture conditions, bearing in mind the suspected microorganisms.