1990 年代以降，入院歴などのリスクを持たない人が市中で感染する市中感染型MRSA（CA-MRSA）の蔓延が世界的に問題になっている．近年，院内でのCA-MRSA 増加も報告されてきており，当院でもPCRbased ORF typing（POT）法の導入後，小児入院患者でのCA-MRSA 推定株の優位を確認した．しかしその疫学は不明な点が多い．そこで2003，2008，2013 年において当院小児入院患者より分離されたMRSA 株を対象にMRSA クローンの細菌学的特徴および疫学を把握する目的で，SCCmec タイピング，multilocus sequence typing（MLST）等の分子疫学解析による検討を薬剤感受性，病原因子検索を含め実施した．SCCmec 型は2003 年以降，NewYork/Japan クローンを中心とするII 型からIV 型への転換が進行し，2013 年には入院株中IV 型の割合が78.6% に達した．また入院IV 型46 株のうちST8 が82.6%，CC8 が93.5% を占め，同時に少なくとも7 種類のクローンが推定された．病原因子についてはPVL 産生株は認められなかったが，入院IV 型46 株中10 株（21.7%）よりtst が検出された．いずれもST8 で，そのうち9 株は潜在的に病原性が高いとされるST8 CA-MRSA/J と推察された．POT 法については，POT1 値とSCCmecII 型，IV 型，CC5，CC8 との間にそれぞれ一定の関連性が認められることを確認した．今後，クローンの動向を把握することは感染症診療や感染対策の基礎として重要性を増すと考えられる．またPOT 法は，限界はあるが日常検査としてそれらを補完する分子疫学解析法として有用である．

海外渡航者にデング熱とジカウイルス感染症に関する適切な情報提供を行うことを目的に，半年以内に発展途上国に滞在予定のある日本からの渡航者を対象に知識状況に関するインターネット調査を実施した．対象者のうち8 割以上が，デング熱やジカウイルス感染症を聞いたことがあると回答し，「蚊が媒介すること」を知っていたのはデング熱で82.8％，ジカウイルス感染症で59.2％だった．一方，「媒介蚊は昼間に吸血すること」を知っていたのはデング熱で20.0％，ジカウイルス感染症で14.2％と少なかった．また，ジカウイルス感染症が「性行為で感染すること」を知っている者は13.2％，「妊婦が感染すると胎児の健康に影響を及ぼすこと」は23.8% といずれも少なかった． デング熱やジカウイルス感染症を媒介する蚊が昼間吸血するという知識は，海外渡航者が予防対策を実施するために重要であり，ジカウイルス感染症が性行為で感染することや，胎児の健康に影響することも含め，今後，日本からの海外渡航者にこれらの情報を提供していく必要がある.

Achromobacter species are non-fermenting, Gram-negative bacilli. While Achromobacter xylosoxidans is known to be an opportunistic pathogen, little is known about infection due to A. xylosoxidans in pregnant women. We herein on report a case of bacteremia caused by A. xylosoxidans in a pregnant woman.
A 35-year-old pregnant Japanese woman was admitted due to urgent premature delivery. The patient developed urosepsis on day 36 following admission and was delivered by emergency caesarean section. Two sets of blood cultures were grown and were positive for A. xylosoxidans. The patient recovered immediately after treatment with a tazobactam/piperacillin regimen. However, the patient reported sudden severe right lower back pain on day 43 following admission. An enhanced abdominal CT showed active bleeding of a right renal angiomyolipoma (AML), for which we performed an arterial embolization. Based on antimicrobial susceptibilities, A. xylosoxidans bacteremia was treated with tazobactam/piperacillin for 14 days, during which the patientʼs clinical symptoms improved.
Our case suggests that A. xylosoxidans could be a causative pathogen of bacteremia in pregnant women and it is presumed that it is caused by urinary tract or catheter-related bloodstream infection.

A 48-year-old man was admitted to our hospital with osteomyelitis of his right thumb. His symptoms had started 1 month previously, 1 week after getting his right thumb caught in a door. MRI showed osteomyelitis of the distal phalanx of the right thumb. Debridement was performed and mycobacteria were isolated from the specimen one week after the culture was started. The mycobacterium was confirmed to be Mycobacterium goodii by 16S rRNA sequencing and an antibiotic susceptibility test. After debridement, treatment with clarithromycin, levofloxacin and amikacin was initiated empirically. According to the susceptibility test and adverse effect of antibiotics, we changed them to levofloxacin and trimethoprim-sulfamethoxazole. The antimicrobial treatment for 9 months resulted in successful resolution of the osteomyelitis.
To our knowledge, this is the first reported case of osteomyelitis caused by Mycobacterium goodii in Japan. Clinicians should consider this organism as a causative agent when treating patients with posttraumatic osteomyelitis.

Mycobacterium haemophilum has been described as a pathogen that causes cutaneous infections, septic arthritis, and pneumonitis in immunocompromised patients. It is being increasingly recognized in patients who have received treatment with anti-tumor necrosis factor-α (TNFα) agents, such as infliximab (IFX). We present a case of a 69-year-old female with a history of rheumatoid arthritis, who following treatment with prednisolone, methotrexate, and IFX for 7 years, developed disseminated M. haemophilum disease, which included cervical lymphadenitis, a lower leg subcutaneous tumor, and an upper eyelid conjunctive mass. Histological examination of biopsy specimens from the eyelid conjunctive mass, lymph node, and lower leg subcutaneous mass revealed granuloma with epithelioid cells and the presence of acid-fast bacilli (AFB) in the lymph node tissue. Molecular genetic analyses using the polymerase chain reaction method excluded Mycobacterium tuberculosis and Mycobacterium avium complex. Biopsy specimens cultured using BACTEC FX bottle (Becton Dickinson) and 2% Ogawa medium at 30℃ showed negative results. Subsequent testing of the frozen tissue specimens from the cervical LN and lower leg subcutaneous mass using mycobacterial DNA,hsp65, rpoB, 16S rRNA gene sequence analysis identified M. haemophilum. The patient was successfully treated with rifampicin, clarithromycin,and sitafloxacin. M.haemophilum infection should be considered in ulcerating skin lesions and/or arthritis, and pneumonia in patients treated with anti-TNFα agents, especially when microscopic observation reveals the presence of AFB and a routine mycobacterial culture remains negative.

Campylobacter fetus has rarely been reported as a pathogen of spontaneous bacterial peritonitis (SBP). A 60-year-old man with cirrhosis and diabetic nephropathy developed diarrhea, abdominal pain, and fever. Abdominal paracentesis revealed a significantly increased neutrophil count in the ascites. He was diagnosed as having SBP and treated empirically with ceftriaxone. Five days later, the blood culture performed on the day of admission yielded spiral-shaped gram negative bacilli. Both ascites and stool cultures were negative. Although conventional biochemical methods could not identify the colony, MALDI-TOF MS (Matrix Assisted Laser Desorption Ionization Time Of Flight Mass Spectrometry) identified it as C. fetus. Ceftriaxone was switched to ampicillin and continued for 21 days in total. He was fully recovered. Only 9 such patients have been reported including our patient, and 8 of them had a favorable outcome. SBP caused by C. fetus tends to present with diarrhea frequently and one patient died. Identification of C. fetus is important to select appropriate antimicrobial therapy. Our case suggests MALDI-TOF MS is a useful tool to identify C. fetus.

A 80-year-old man with non-tuberculous mycobacteriosis developed dyspnea and right chest pain and was therefore admitted to our hospital. <BR>Chest computed tomography demonstrated a right pleural effusion. Analysis of the aspirate from the pleural effusion revealed empyema and evidence of gram-positive coccal bacteria. Because his empyema did not resolve with chest tube drainage and antibiotics, video-assisted thoracoscopic surgery was performed,and Parvimonas micra was cultured from the pleural effusion. The sequence of the 16S rRNA gene was 99.4% identical to that of P. micra strain. Although the P. micra infection in the pleural cavity is uncommon, it should be considered as a pathogenic bacterium of empyema.