成人および小児における腸チフス感染症の病原体ゲノム調査では、臨床転帰と感染遺伝子型との間に関連性はないことが明らかになっている

Pathogen genomic surveillance of typhoidal infection in adults and children reveals no association between clinical outcomes and infecting genotypes.

• Carl D Britto
• Sitarah Mathias
• Ashish Bosco
• Zoe A Dyson
• Gordon Dougan
• Savitha Raveendran
• V L Abin
• Sanju Jose
• Savitha Nagaraj
• Kathryn E Holt
• Andrew J Pollard

抄録

背景:

インドは腸チフスの風土病であり，患者間の臨床症状のばらつきが宿主，環境，病原体のいずれの要因によるものかは不明である．各症例から臨床、検査室、人口統計学的データを収集し、細菌分離株を全ゲノム配列決定の対象とした。成人疾患と小児疾患の違いを把握するために、成人患者と小児患者の比較分析を行った。

Background: India is endemic for enteric fever, and it is not known whether the variations in clinical manifestations between patients are due to host, environmental or pathogen factors.Blood culture surveillance was conducted at St. John's Medical College Hospital, Bangalore, between July 2016 and June 2017. Clinical, laboratory and demographic data were collected from each case, and bacterial isolates were subjected to whole genome sequencing. Comparative analysis between adults and paediatric patients was carried out to ascertain differences between adult and paediatric disease.

結果:

血液培養で確認された113例のうち，若年成人（16～30歳）が47％，小児（15歳未満）が37％を占めた。呈示時貧血は46％に認められ，呈示時白血球数異常は19％に認められた．大半が入院治療を受けており（70％），成人の入院期間は小児に比べて有意に長かった（＝0.002）．関節炎、急性溶血、2つの異なるTyphi遺伝子型を持つチフス感染を繰り返した1例を含む非定型の症例があった。感染遺伝子型・血清型と治療状況（外来・入院），隔離月数，入院期間，患者の年齢（成人・小児），抗菌薬感受性，Widal陽性率，血液学的指標との間には関連性はなかった．

Results: Among the 113 cases of blood culture-confirmed enteric fever, young adults (16-30 years) and children < 15 years accounted for 47% and 37% of cases, respectively. Anaemia on presentation was seen in 46% of cases, and 19% had an abnormal leucocyte count on presentation. The majority received treatment as inpatients (70%), and among these, adults had a significantly longer duration of admission when compared with children ( = 0.002). There were atypical presentations including arthritis, acute haemolysis and a case of repeated typhoid infection with two separate Typhi genotypes. There was no association between infecting genotype/serovar and treatment status (outpatient vs inpatient), month of isolation, duration of admission, patient age (adult or child), antimicrobial susceptibility, Widal positivity or haematologic parameters.

結論:

南インドでは多くの公衆衛生上の懸念がある中、腸熱は、宿主や環境因子に起因する可能性が高い小児および成人患者の非特異的な、また珍しい臨床症状を有しており、病院負担の大きな要因となっています。治療や予防戦略の情報を提供するためには、ロバストな臨床サーベイランスと病原体集団構造のモニタリングが必要である。

Conclusions: Amidst the many public health concerns of South India, enteric fever continues to contribute substantially to hospital burden with non-specific as well as uncommon clinical features in both paediatric and adult populations likely driven by host and environmental factors. Robust clinical surveillance as well monitoring of pathogen population structure is required to inform treatment and preventive strategies.

© The Author(s) 2020.