2014 年10 月，水痘ワクチンは1 回の任意接種から2 回の定期接種に変更された．今回，定期接種化前約 7 年間の初回水痘ワクチン接種後の抗体非陽転（一次性ワクチン不全）児に対する追加接種の効果を報告する． 2007 年11 月～2014年5月に1.1～14.5（中央値1.7）歳の健康小児273 名に水痘ワクチンを接種し，その接種前・後（4～6 週）のimmune adherence hemagglutination（IAHA）およびglycoprotein-based enzymelinked immunosorbent assay（gpELISA）抗体価を測定すると共に接種後4 週間の副反応を調査した．IAHA 抗体非陽転の一次性ワクチン不全児には追加接種を勧め，接種後の両抗体価測定と副反応調査を行った．2015 年5 月に273 名へアンケート用紙を郵送し，接種後の水痘および帯状疱疹罹患の有無を追跡調査した．初回接種後のIAHA 抗体陽転率は75％，平均陽転抗体価（Log2）は4.7，gpELISA 抗体陽転率は84％， 平均陽転抗体価（Log10）は2.4 であった．一次性ワクチン不全で追加接種に同意した54 名に，初回接種から81～714（中央値139）日に追加接種を行った．追加接種後のIAHA 抗体陽転率は98％，平均陽転抗体価 （Log2）は5.8 であり，初回接種より高い陽転率および抗体価であった（p＜0.01）．gpELISA では，追加接種後の抗体陽性率は100％，平均陽性抗体価（Log10）は3.6 であり，IAHA 抗体と同様に初回接種より有意に高い抗体反応が認められた（p＜0.01）．副反応は概ね軽微で，初回接種と追加接種の間で発熱（≧37.5℃），局所反応および局所以外の発疹の発生率に有意差は無かった． アンケートは185 名から回答があり（回答率68％），初回接種から回答までの期間は1.0～7.5（中央値4.0）年であった．初回接種後の水痘罹患率は抗体陽転非追加接種群17％，抗体非陽転追加接種群14％であり，両群間に有意差は無かった．結論として，初回水痘ワクチン接種後の一次性ワクチン不全児に対する追加接種は安全性に問題なく，良好な抗体反応が期待できる．

本邦においてCampylobacter jejuni とCampylobacter coli による腸管外感染症や菌血症・敗血症について多数例の報告は極めて少ない．これら2 菌種による侵襲性感染症の臨床的・細菌学的特徴を明らかにするため，地域中核病院において2000～2015 年に無菌検体から同菌が分離された症例を対象に，診療録を後方視的に検討した．該当症例は9 例で全例菌血症であった．肝硬変や悪性新生物など基礎疾患を有する症例は3 例でいずれも60 歳以上で，一方残り6 例は40 歳未満の健常人であった．全例38.5℃以上の高熱を認めた．基礎疾患を有する3 例は，有しない6 例と比較すると，胃腸炎症状の合併率が低かった（1/3 例vs 4/6 例）．抗菌薬感受性に関して，評価できた8 株全例で，imipenem/cilastatin，kanamycin，erythromycin に感性で， 2 株がlevofloxacin に耐性であった．抗菌薬加療は8 例で施行され，1 例は無治療で自然軽快した．予後の判明した8 例は全例で完治し，重篤な後遺症や再発例はなかった．過去に報告されている日本人14 症例についても検討したところ，高熱や基礎疾患の有無と胃腸炎合併率について同様の特徴を認め，3 例のX 連鎖無ガンマグロブリン血症患者全例に再発を認めたことが特徴的であった．既報と合わせた解析で，臨床症候群と治療の点から，2 群に大別できた．一つ目は背景疾患を保有しない小児・若年成人群で胃腸炎に合併した菌血症が主体で，治療は短期間または不要の群，二つ目は背景疾患を保有し，菌血症と場合によっては腸管外感染症を合併し，消化器症状を呈する割合が低く，適切な静脈内抗菌薬治療が必要な群である．本研究は，侵襲性C. jejuni/coli 感染症では我が国最多数例の報告であり，既報を合わせた検討により重要な疫学情報を提供した．

市販鶏レバーから分離されたextended-spectrum β-lactamase（ESBL）産生Escherichia coli 40 株，および臨床材料から分離されたESBL 産生E. coli 43 株ならびにKlebsiella pneumoniae 42 株を対象として，DNA シークエンスによりblaCTX-M-typing を実施した．各bla_CTX-M group 型別を実施したところ，bla_CTX-M-1 group に属する31 株の中ではbla_CTX-M-1 が13 株と最も多く，全て鶏レバー由来E. coli であった．次いで，bla_CTX-M-55 が 9 株でその由来は鶏レバーのE. coli が8 株および患者のE. coli が1 株であった．さらに，bla_CTX-M-15 7 株は，何れも患者由来株でその内訳は，E. coli が6 株およびK. pneumoniae が1 株であった．bla_CTX-M-2 group に属する 39 株は全てbla_CTX-M-2 であった．bla_CTX-M-9 group に属する55 株は，bla_CTX-M-14 保有株が36 株と最も検出頻度が高く，その内訳は，患者由来E. coli が20 株，患者由来K. pneumoniae が13 株および鶏レバー由来E. coli が3 株であった．次いで検出頻度が高かったのはbla_CTX-M-27 17 株で，その内訳は，患者由来株のE. coli 10 株およびK. pneumoniae 7 株であった．さらに患者由来E. coli からbla_CTX-M-9，患者由来K. pneumoniae からbla_CTX-M-90 が1 株ずつ検出された．これらの結果から，鶏レバー由来E. coli はbla_CTX-M-1，bla_CTX-M-2 およびbla_CTX-M-55，患者由来E. coli はbla_CTX-M-14 とbla_CTX-M-27，患者由来K. pneumoniae はbla_CTX-M-2，bla_CTX-M-14 およびbla_CTX-M-27 で，保有するbla_CTX-M 型が異なっていた．そのため，鶏レバー由来のESBL 産生E. coli が，直接ヒトの腸管内に定着した可能性は低いと考えられた．

We present 3 cases of ocular syphilis in patients who had been newly diagnosed as having HIV. All the patients had only complained of ophthalmologic symptoms at the time of their initial visit. Treatment with penicillin was successful, resulting in no significant sequelae. Ocular syphilis may lead to reduced visual acuity or even blindness if left untreated. However, the diagnosis may be challenging, since patients may lack symptoms that are commonly observed in cases with primary and secondary syphilis. Considering the recent increase in the number of syphilis patients, clinicians should be aware of ocular syphilis and should have a high index of suspicion for syphilis in any patient at risk so as to ensure a prompt diagnosis.

An 84-year-old man was admitted to our hospital with bloody sputum. He was found to have a right lower lobe wedge-shaped nodular lesion with chest X-ray and computed tomography of the chest. Ceftriaxone and minocycline were started empirically based on a working diagnosis of community-acquired pneumonia. Streptococcus parasanguinis was isolated with sputum cultures obtained on three consecutive days and was identified based on its biochemical properties. S. parasanguinis is a member of the sanguinis group of viridans Streptococci. It is known as a causative pathogen for endocarditis. There are very few reports of S. parasanguinis associated with pulmonary infections. The present report describes the association of S. parasanguinis with a wedge-shaped nodular lesion in the lungs.

We report the case of a pediatric patient in whom a spinal congenital dermal sinus was detected after the onset of anaerobic bacterial meningitis. The patient was a 4-month-old boy. He had a recurrent fever for 2 weeks before admission. On admission, he presented with a convulsive status and a bulging anterior fontanel. The previously consulted physician had made a diagnosis of bacterial meningitis. Spinal fluid cultures tested positive for Peptoniphilus asaccharolyticus. Magnetic resonance imaging (MRI) showed a spinal subdural abscess and cranial subdural hydrops；therefore, the patient was transported to our hospital for surgical treatment. A sacral dimple was noted on his lower back, and an MRI showed a spinal congenital dermal sinus. Antimicrobial therapy, cranial subdural aspiration, dermal sinus excision, and drainage were performed. He was discharged on the 60^th hospital day. When pathogens such as Staphylococcus aureus or Escherichia coli,Proteus sp. or anaerobic bacteria invade through a dermal sinus, it can result in meningitis. Involvement of a dermal sinus should be suspected when meningitis is caused by these pathogens or when recurrent meningitis occurs.

We report a patient with leptospirosis caused by infection with Leptospira interrogans serovar Rachmati. A 30-year-old Japanese man took part in a survival camp on Iriomote Island, Okinawa, from July 9 to July 15, 2014. During the camp, he swam in the river and kayaked. He developed a high fever and fatigue 7 days after completing his trip and was admitted to our hospital on July 22. On admission, he complained of a posterior cervical pain and a loss of appetite. Laboratory findings revealed granulocytosis, mildly elevated AST and ALT levels, elevated BUN and Cr levels, and a significantly elevated CRP level. No pathogenic bacteria were isolated from blood, urine, or cerebrospinal fluid cultures. We included leptospirosis in the differential diagnosis because of the patientʼs history of participating in a survival camp on Iriomote Island. Minocycline 200mg, p.o. showed an excellent efficacy. The Leptospira flagellar gene FlaB was detected using a cerebrospinal fluid PCR. A microscopic agglutination test (MAT) during the convalescent stage demonstrated significant increases in antibodies against L. interrogans serovar Rachmati, confirming the diagnosis of leptospirosis. A medical history including occupation and recent travel history, and an adequate specimen sampling are crucial for the accurate and early diagnosis of leptospirosis.

Infection with the Epstein-Barr virus (EBV) is a common disease and is mainly asymptomatic during childhood, whereas infectious mononucleosis with clinical signs such as fever, pharyngitis, lymphadenopathy and hepatosplenomegaly often occurs in adolescents and adults with primary infection. Acalculous cholecystitis has been reported as a rare complication. We report herein a case of acalculous cholecystitis accompanied by infectious mononucleosis by EBV, which was treated successfully by medical treatment. A 33-yearold woman who had been admitted by fever, pharyngitis and lymphadenopathy developed a right upper quadrant pain, that was diagnosed as acalculous cholecystitis based on an imaging study. Antibiotic treatment did not resolve the symptoms, and surgical intervention was considered. We diagnosed her as having infectious mononucleosis based on a typical physical presentation and seropositivity for the EBV viral capsid antigen, suggesting that the acalculous cholecystatis might have been a complication of the EBV infection. After the administration of glucocorticoid and acyclovir, the patient became afebrile and the abdominal pain disappeared. Though acalculous cholecystitis rarely accompanies infectious mononucleosis caused by EBV,clinicians should be aware of this complication to avoid unnecessary cholecystectomy.

Meningococcal infection is among the most devastating diseases. It is rarely seen in Japan. However,several environmental and host factors have been associated with increased risks of Neisseria meningitidis infection. We present a case of invasive N. meningitidis infection that revealed the presence of multiple myeloma. A 55-year-old Japanese man was admitted with fever and altered consciousness. He was sent to the intensive care unit for septic shock and disseminated intravascular coagulation. In addition to standard septic shock and multiple organ failure treatment, polymyxin-B immobilized column direct hemoperfusion was performed. His blood culture was positive for N. meningitidis. The patient gradually improved and was discharged on day 35. We evaluated the risk factors for the development of meningococcal infection. A laboratory examination showed that the patient was negative for human immunodeficiency virus antibody and had a normal total complement function. However, his serum immunoglobulin G level was high, and serum and urine protein electrophoresis detected a monoclonal gammopathy. A bone marrow examination led to the diagnosis of multiple myeloma. Because N. meningitidis bacteria spreads between individuals in close contact through the exchange of oral secretions, droplet precautions and antimicrobial chemoprophylaxis (ciprofloxacin, 500mg) were implemented to prevent the spread of the meningococcal infection. Sporadic meningococcal infection warrants an evaluation for immunodeficiency and the prevention of secondary infection.

The blood culture contamination rate is often used to validate specimen-collection procedures. CUMITECH has set its optimal target to be 2% to 3%. However, the term “contamination rate”has been defined in many ways, limiting its generalizability. The definitions used in earlier studies can be divided into two categories；definitions based on clinical judgements, and those based on preset rules. According to each principle, the equation must be composed of a defined numerator and denominator. The problem with clinical definitions is that the decision is inevitably subjective, and the process is too cumbersome. Also, if the number of positive cultures is used as the denominator, the value would be equivalent to the positive predictive value, given that contamination is regarded as a “positive case.”Thus, the value would not be useful for validating a procedure. On the other hand, when the preset algorithm was adopted, true infection would,to some degree, inevitably be classified as contamination. Also, if the algorithm adopted the number of blood culture sets as the denominator and contamination was defined as the identification of 1 or more specified organisms in only 1 of multiple sets of blood cultures, its theoretical maximum value would not be 100%. This is a problem because the value is a mixture of several numbers with different scales. In other words,whether the blood cultures are collected once, twice, or thrice or more a day would affect the result. The study cited by CUMITECH aimed to evaluate the equivalence between the clinical definition and the laboratory definition with preset rules, rather than to establish a benchmark for the contamination rate. It is undesirable for the number to be perceived as a benchmark. “A Guide to Blood Culture”(2013) by the Japanese Society for Clinical Microbiology introduced a calculation for the contamination rate, but the definition of the term ”number of specimens”in the formula is ambiguous. In addition, the references cited in the guide do not concern contamination and do not even mention the definition of contamination rate. Thus, it is impossible to confirm the definition. In view of the weaknesses of these previous works, we defined the contamination rate as a benchmark for the validation of blood culture procedures as follows. [number of series in which 1 or more specified organisms (*) were identified in only 1 of multiple sets of blood cultures] / [total number of multiple sets of blood cultures in the series] *coagulase-negative staphylococci, Propionibacterium acnes, Micrococcus spp., Viridans-group streptococci,Corynebacterium spp., and Bacillus spp., but not B. anthracis