Severe Infectious Disease Research Articles

Virulence Profiles of Wild-Type, P.1 and Delta SARS-CoV-2 Variants in K18-hACE2 Transgenic Mice.

Since December 2019, the world has been experiencing the COVID-19 pandemic caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), and we now face the emergence of several variants. We aimed to assess the differences between the wild-type (Wt) (Wuhan) strain and the P.1 (Gamma) and Delta variants using infected K18-hACE2 mice. The clinical manifestations, behavior, virus load, pulmonary capacity, and histopathological alterations were analyzed. The P.1-infected mice showed weight loss and more severe clinical manifestations of COVID-19 than the Wt and Delta-infected mice. The respiratory capacity was reduced in the P.1-infected mice compared to the other groups. Pulmonary histological findings demonstrated that a more aggressive disease was generated by the P.1 and Delta variants compared to the Wt strain of the virus. The quantification of the SARS-CoV-2 viral copies varied greatly among the infected mice although it was higher in P.1-infected mice on the day of death. Our data revealed that K18-hACE2 mice infected with the P.1 variant develop a more severe infectious disease than those infected with the other variants, despite the significant heterogeneity among the mice.

TLR Responses in Preterm and Term Infant Cord Blood Mononuclear Cells.

Preterm infants are more susceptible to severe bacterial and viral infectious diseases than their full-term counterparts. A major contributor to this increased susceptibility may be due to differences in their ability to respond to pathogens. While studies have demonstrated altered bacterial Toll-like receptor (TLR) responses, there is limited data on viral TLR responses in preterm infants. In this study, cord blood mononuclear cells (CBMCs) from 10 moderately preterm (30.4-34.1 wGA), 10 term (37-39.5 wGA) infants, and 5 adults were stimulated with TLR2 (lipoteichoic acid), TLR3 (poly I:C), TLR4 (lipopolysaccharide), TLR7/8 (R848), and TLR9 (CpG-ODN 2216) agonists. Following stimulation, the cellular response was measured by intracellular flow cytometry to detect cell-specific NF-κB (as a marker of the inflammatory response), and multiplex assays were used to measure the cytokine response. This study found that preterm and term infants exhibit very similar baseline TLR expression. In response to both bacterial and viral TLR agonists comparing cell-specific NF-κB activation, preterm infants exhibited increased monocyte activation following LTA stimulation; however, no other differences were observed. Similarly, no difference in cytokine response was observed following stimulation with TLRs. However, a stronger correlation between NF-κB activation and cytokine responses was observed in term infants following poly I:C and R848 stimulation compared to preterm infants. In contrast, despite similar TLR expression, adults produced higher levels of IFN-α following R848 stimulation compared to preterm and term infants. These findings suggest preterm and term infants have a similar capacity to respond to both bacterial and viral TLR agonists. As preterm infants are more likely to develop severe infections, further research is required to determine the immunological factors that may be driving this and develop better interventions for this highly vulnerable group.

Immunotherapies against human bacterial and fungal infectious diseases: A review.

Nations' ongoing struggles with a number of novel and reemerging infectious diseases, including the ongoing global health issue, the SARS-Co-V2 (severe acute respiratory syndrome coronavirus 2) outbreak, serve as proof that infectious diseases constitute a serious threat to the global public health. Moreover, the fatality rate in humans is rising as a result of the development of severe infectious diseases brought about by multiple drug-tolerant pathogenic microorganisms. The widespread use of traditional antimicrobial drugs, immunosuppressive medications, and other related factors led to the establishment of such drug resistant pathogenic microbial species. To overcome the difficulties commonly encountered by current infectious disease management and control processes, like inadequate effectiveness, toxicities, and the evolution of drug tolerance, new treatment solutions are required. Fortunately, immunotherapies already hold great potential for reducing these restrictions while simultaneously expanding the boundaries of healthcare and medicine, as shown by the latest discoveries and the success of drugs including monoclonal antibodies (MAbs), vaccinations, etc. Immunotherapies comprise methods for treating diseases that specifically target or affect the body's immune system and such immunological procedures/therapies strengthen the host's defenses to fight those infections. The immunotherapy-based treatments control the host's innate and adaptive immune responses, which are effective in treating different pathogenic microbial infections. As a result, diverse immunotherapeutic strategies are being researched more and more as alternative treatments for infectious diseases, leading to substantial improvements in our comprehension of the associations between pathogens and host immune system. In this review we will explore different immunotherapies and their usage for the assistance of a broad spectrum of infectious ailments caused by various human bacterial and fungal pathogenic microbes. We will discuss about the recent developments in the therapeutics against the growing human pathogenic microbial diseases and focus on the present and future of using immunotherapies to overcome these diseases. Graphical AbstractThe graphical abstract shows the therapeutic potential of different types of immunotherapies like vaccines, monoclonal antibodies-based therapies, etc., against different kinds of human Bacterial and Fungal microbial infections.

Large Multicountry Outbreak of Invasive Listeriosis by a Listeria monocytogenes ST394 Clone Linked to Smoked Rainbow Trout, 2020 to 2021.

Whole-genome sequencing (WGS) has revolutionized surveillance of infectious diseases. Disease outbreaks can now be detected with high precision, and correct attribution of infection sources has been improved. Listeriosis, caused by the bacterium Listeria monocytogenes, is a foodborne disease with a high case fatality rate and a large proportion of outbreak-related cases. Timely recognition of listeriosis outbreaks and precise allocation of food sources are important to prevent further infections and to promote public health. We report the WGS-based identification of a large multinational listeriosis outbreak with 55 cases that affected Germany, Austria, Denmark, and Switzerland during 2020 and 2021. Clinical isolates formed a highly clonal cluster (called Ny9) based on core genome multilocus sequence typing (cgMLST). Routine and ad hoc investigations of food samples identified L. monocytogenes isolates from smoked rainbow trout filets from a Danish producer grouping with the Ny9 cluster. Patient interviews confirmed consumption of rainbow trout as the most likely infection source. The Ny9 cluster was caused by a MLST sequence type (ST) ST394 clone belonging to molecular serogroup IIa, forming a distinct clade within molecular serogroup IIa strains. Analysis of the Ny9 genome revealed clpY, dgcB, and recQ inactivating mutations, but phenotypic characterization of several virulence-associated traits of a representative Ny9 isolate showed that the outbreak strain had the same pathogenic potential as other serogroup IIa strains. Our report demonstrates that international food trade can cause multicountry outbreaks that necessitate cross-border outbreak collaboration. It also corroborates the relevance of ready-to-eat smoked fish products as causes for listeriosis. IMPORTANCE Listeriosis is a severe infectious disease in humans and characterized by an exceptionally high case fatality rate. The disease is transmitted through consumption of food contaminated by the bacterium Listeria monocytogenes. Outbreaks of listeriosis often occur but can be recognized and stopped through implementation of whole-genome sequencing-based pathogen surveillance systems. We here describe the detection and management of a large listeriosis outbreak in Germany and three neighboring countries. This outbreak was caused by rainbow trout filet, which was contaminated by a L. monocytogenes clone belonging to sequence type ST394. This work further expands our knowledge on the genetic diversity and transmission routes of an important foodborne pathogen.

Mussel antiviral transcriptome response and elimination of viral haemorrhagic septicaemia virus (VHSV)

As filter-feeding bivalves, mussels have been traditionally studied as possible vectors of different bacterial or viral pathogens. The absence of a known viral pathogen in these bivalves makes it particularly interesting to study the interaction of the mussel innate immune system with a virus of interest. In the present work, mussels were challenged with viral haemorrhagic septicaemia virus (VHSV), which is a pathogen in several fish species. The viral load was eliminated after 24 h and mussels evidenced antiviral activity towards VHSV, demonstrating that the virus was recognized and eliminated by the immune system of the host and confirming that mussels are not VHSV vectors in the marine environment. The transcriptome activating the antiviral response was studied, revealing the involvement of cytoplasmic viral sensors with the subsequent activation of the JAK-STAT pathway and several downstream antiviral effectors. The inflammatory response was inhibited with the profound downregulation of MyD88, shifting the immune balance towards antiviral functions. High modulation of retrotransposon activity was observed, revealing a mechanism that facilitates the antiviral response and that had not been previously observed in these species. The expression of several inhibitors of apoptosis and apoptosis-promoting genes was modulated, although clear inhibition of apoptosis in bivalves after severe viral infection and subsequent disease was not observed in this study. Finally, the modulated expression of several long noncoding RNAs that were correlated with genes involved in the immune response was detected.

PRRSV-induced inflammation in pulmonary intravascular macrophages (PIMs) and pulmonary alveolar macrophages (PAMs) contributes to endothelial barrier function injury

Porcine reproductive and respiratory syndrome (PRRS) is a severe infectious disease currently devasting the global pig industry. PRRS is characterized by intense inflammation and severe damage to the alveolar-capillary barrier. Therefore, it is crucial to uncover the underlying mechanism by which the PRRS virus (PRRSV) induces inflammatory responses and barrier function damage. In addition to porcine alveolar macrophages (PAMs), the primary target cells of PRRSV infection in vivo, pulmonary intravascular macrophages (PIMs) are also susceptible to PRRSV infection. However, the poor isolation efficiency limits the study of PRRSV infection in PIMs. In this study, we optimized the isolation method to obtain PIMs with higher purity and yield and demonstrated that PRRSV’s infection kinetics in PIMs were similar to those in PAMs. Notably, PIMs exhibited a more acute inflammation process during PRRSV infection than PAMs, as evidenced by the earlier upregulation and higher levels of pro-inflammatory cytokines, including TNF-α and IL-1β. More acute endothelial barrier disfunction upon PRRSV infection was also observed in PIMs compared to in PAMs. Mechanistically, PRRSV-induced TNF-α and IL-1β could cause endothelial barrier disfunction by dysregulating tight junction proteins, including claudin 1 (CLDN1), claudin 8 (CLDN8) and occludin (OCLN). Our findings revealed the crucial and novel roles of PIMs in facilitating the progression of inflammatory responses and endothelial barrier injury and provided new insights into the mechanisms of PRRSV’s induction of interstitial pneumonia.

Genetic and Biochemical Detection of Salmonella enterica Isolated from Patients Suffering Watery Diarrhea and Typhoid Fever in Babylon Province

Background: Salmonellosis is a severe infectious zoonotic disease, which increases the importance of identifying and controlling the causative strains. Objectives: This study aimed to develop a rapid molecular diagnostic test to determine and purify bacterial isolates based on the specific primer. SE1472298-2 for Salmonella serovar enteritidis; gene STM4497 demonstrated specificity for Salmonella serovar typhimurium and gene O antigen synthesis tyv for Salmonella serovar typhi isolated from patients in Babylon province, Iraq. Materials and Methods: Two hundred clinical stool specimens were collected from patients suffering from watery diarrhea. Blood specimens obtained from patients with typhoid fever who were admitted to three hospitals of Babylon Governorate. Results: There were a total of 200 samples; 34 (17%) were discovered by biochemical tests. The diagnosis of these samples was confirmed by polymerase chain reaction, depending on the target gene, so the number of isolates was 25 (73.53%), Salmonella enteritidis 13 (52%) Salmonella typhimurium 6 (24%), and Salmonella typhi 6 (24%). Conclusion: Molecular techniques, particularly polymerase chain reaction, can rapidly and precisely identify Salmonella isolates.

アトピー性皮膚炎を基礎疾患とし肺動脈弁感染性心内膜炎を発症した1例(A case of isolated pulmonary valve infective endocarditis with atopic dermatitis)

アトピー性皮膚炎（atopic dermatitis: AD）は慢性皮膚炎であり，感染性心内膜炎（infective endocarditis: IE）など重症感染症の合併報告はコントロール不良なAD例であり，さらに肺動脈弁の孤立性IE報告例はない。症例は50歳代の男性，既往はコントロール良好な小児期からのADあり。手指消毒剤により指尖部乾燥が増悪していた。入院5日前に発熱し近医から抗菌薬を処方されたが，入院前日に体動困難となり他院へ搬送され敗血症の診断で入院した。翌日精査加療目的に当院へ転院した。来院時意識清明，呼吸循環動態は保たれていたが，40℃の発熱と右肘の発赤腫脹，前腕の有痛性浮腫性紅斑を認めた。血液検査で血小板が3.6万に低下しており敗血症と診断し広域抗菌薬を投与し救命センターに入室とした。入院後右肘穿刺液，左前腕筋間の膿瘍，血液培養からメチシリン感受性ブドウ球菌が検出されセファゾリンにて治療を継続した。入院15日目まで複数回の経胸壁・食道心臓超音波検査とCT検査では疣贅を認めず，ガリウムシンチグラフィーでも有意な所見を認めなかったが，入院33日目に施行した造影CT検査にて肺動脈弁の疣贅を確認した。血液培養陰性化後6週間抗菌薬を投与し，入院51日目に退院した。ADの既往のある菌血症症例は肺動脈弁領域のIEの可能性も念頭に繰り返し評価し考慮する必要がある。 Atopic dermatitis (AD) is a common chronic dermatitis, and severe infectious diseases triggered by AD have been reported. We describe a 58–year–old Japanese male with AD who developed pulmonary–valve infective endocarditis. The dryness of his fingertips had been exacerbated by hand sanitizer. Five days before his admission, he had a fever and was prescribed antibiotics. Two days before admission, he was admitted to a general hospital but was then transferred to our hospital for treatment. On admission, he had a fever of 40℃ and painful edematous erythema of his forearm, but his respiratory and circulatory dynamics were maintained. Platelets had dropped to 36,000, and sepsis was diagnosed. Methicillin–sensitive staphylococci were detected in the right elbow’s fluid and blood culture, and we changed the antibiotics to cefazolin. Enhanced CAT scanning and cardiac ultrasound showed no abnormalities until the 15th day of hospitalization. On the 33rd day of hospitalization, vegetation of the pulmonary valve was confirmed. Antibiotics were administered for 6 weeks, and the patient recovered. Clinicians should be aware that patients with a history of AD may develop serious infections even if their AD is well controlled. アトピー性皮膚炎（atopic dermatitis: AD）は日常診療でよく遭遇する疾患である 1が，皮膚の保護機能破綻から血流感染を起こし，感染性心内膜炎（infective endocarditis: IE）などの重篤な感染症を起こすことがあるとされている 2。過去にIEを合併した報告はADのコントロールが不良なものがほとんどであり，さらに肺動脈弁に孤立性にIEを認めた報告例はない。今回ADの増悪を契機として，孤立性肺動脈弁IEを合併した1例を経験し，ADの既往がある患者の診療に関して示唆を与えるため報告する。 なお，本論文は症例報告のため倫理委員会の承諾を得る必要はなく，個人情報保護法に基づき匿名化している。また，患者より論文の出版に関する同意を得ている。 患 者：50歳代の男性 既往歴：小児期にADを発症したが保湿剤のみでコントロールは良好であった。外傷・直近の歯科治療歴はない。 現病歴：入院5日前に38℃台の発熱を認め近医を受診，肺炎を疑われクラリスロマイシンを処方された。入院前日に呼吸困難を自覚し体動困難となり他院へ救急搬送された。前医搬送時，40度の発熱，咽頭発赤，右肘に痂疲を伴う発赤および腫脹，四肢の湿疹を認めた。重症軟部組織感染の可能性が考えられ当院に加療目的に転送された。 来院時現症：意識レベル；Glasgow coma scale（GCS）E4V5M6，体温；40℃（腋窩），血圧；110/52mmHg，心拍数；106/分（整），呼吸数；24/分（整），経皮的酸素飽和度；99%（室内気），瞳孔；2.0mm/2.0mm，対光反射；迅速/迅速，眼球結膜出血斑なし，呼吸音；清，心雑音なし，腹部平坦・軟・圧痛なし。皮膚；右肘伸側に痂疲形成を伴う発赤腫脹と，両側前腕に直径2～3cm大の有痛性の浮腫性紅斑周囲には粟粒大の紅色丘疹を認めた。指尖部に一部表皮剥脱・剥離を認めた。 来院時検査所見： ＜血液検査＞ 血算；WBC 4,500/µL，RBC 278万/µL，Hb 10.7g/dL，Ht 30.5%，PLT 3.6万/µL，生化学；Na 135mmol/L，K 3.7mmol/L，Cl 103mmol/L，Ca 7.5mg/dL，IP 1.7mg/dL，Mg 1.4mg/dL，Glu 115mg/dL，ALB 1.7g/dL，BUN 14.8mg/dL，CRE 0.85，T–Bil0.4mg/dL，γ–GTP 57IU/L，AST 43IU/L，ALT 32IU/L，CK 402IU/L，CRP 29.12mg/dL，凝固；PT 79.8%，PT比1.14，PT–INR 1.16，APTT 40.5sec，FDP 4.9µg/mL ＜動脈血液ガス分析（室内気）＞ pH 7.508，pCO2 25.7mmHg，pO2 78.1mmHg，HCO3− 23.4mmol/l，BE −1.2mmol/L，Lac 1.0mmol/L ＜画像所見＞ 胸部レントゲン；肺野に異常陰影を認めない。全身CT；四肢・体幹に膿瘍を疑う所見を認めない。 経過：臨床経過から敗血症を疑いバンコマイシンとメロペネムを投与し集中治療室に入室とした。入院2日目，経食道心臓超音波を施行したが疣贅と弁膜症を疑う所見は認めなかった。血液と右肘伸側皮下の液体貯留部の培養からは黄色ブドウ球菌が検出された（Fig. 1）。 Skin findings. (a) right elbow Day1, (b) left forearm Day1, (c) right forearm Day3, (d) right lower limbs Day3 入院3日目，十分な輸液にもかかわらず平均血圧は50mmHgに低下し，ノルアドレナリンを開始，他の病原体による感染の可能性を考慮しミノサイクリンを追加投与した。右肘部の発赤は改善したが四肢の発赤は拡大し，入院5日目に血液培養からMSSA（methicillin–susceptible Staphylococcus aureus）が検出されたため，抗菌薬をセファゾリンに変更した。さらに毒素性ショック症候群（toxic shock syndrome: TSS）の可能性も考慮しクリンダマイシンを追加投与した。 入院7日目に造影CTを熱源精査目的に施行したが血管内に有意所見は認められなかった。 入院8日目血液培養は陰性となり，体温も解熱傾向かつ紅斑は退色傾向となったが左前腕に紅斑が残存していたため，超音波で観察したところ撓側手根伸筋と腕橈骨筋の筋間に液体貯留を認め，切開・洗浄を実施した。同部位から提出した培養においてもMSSAが検出された。 入院9日目にノルアドレナリンは終了し，TSST–1（toxic shock syndrome toxin–1）陰性を確認したためクリンダマイシンも終了した（Fig. 2）。 The clinical course. Time course of the patient in therapeutic interventions. その後状態は安定していたが37.5℃前後の微熱が継続しており，IEの可能性を考え経胸壁心臓超音波検査を数日おきに繰り返し施行し，入院12日目にCT検査を施行したが有意な所見は認めなかった。入院15日目には経食道心臓超音波検査を施行したが，有意な所見は認めなかった。その後も感染の可能性を念頭に入れ，入院20日目にCT検査，21日目にガリウムシンチグラフィー検査を施行したが有意な所見は認めなかった。精査にて有意な所見は認めなかったが，血液培養が陽性であったことからIEに準じて抗菌薬を投与する方針とした。その後も経胸壁心臓超音波検査や身体所見に変化を認めなかったが，入院33日目に造影CT検査を施行したところ肺動脈弁に疣贅を疑う所見を認めた（Fig. 3）。経食道心臓超音波を実施したところ肺動脈弁に疣贅を認めたため肺動脈弁の孤立性のIEと診断した（Fig. 4）。右心系のIEであり手術は選択せず，血液培養の陰性化した入院8日目から6週間セファゾリンを経静脈的に投与した。 Enhanced CAT–scan. Day33rd. φ8mm vegetation in pulmonary valve. Transesophageal echocardiography. 8×3mm abnormal echo in pulmonary valve’s anterior semilunar cusp. 入院51日目に経胸壁心臓超音波検査を実施し疣贅に著変なく弁破壊も認めないことから，入院54日目に独歩で自宅退院した。 本症例はADの既往がある患者においてIEを肺動脈弁に合併した症例であり，ADの既往がある患者に対する診療において2つの点で示唆を与える。 1つ目はIEの合併についてである。ADを基礎疾患に持つ患者はIE，化膿性脊椎炎，腸腰筋膿瘍などの重篤な感染を合併することがあると報告され 3，慢性的な掻爬による皮膚の破綻が病原体の侵入門戸となる可能性 4に加え，免疫システムとして存在する抗菌ペプチドのcathelicidins（LL–37）とβデフェンシン2（HBD–2）の減少は，LL–37とHBD–2の組合せが黄色ブドウ球菌への相乗的な抗菌活性を持っていることから黄色ブドウ球菌に対する脆弱性 5とコロニー形成に対する感受性を高める役割を果たしている可能性 6が示唆されている。ADにIEを合併した報告例においては，ADが重症でコントロール不良である症例がほとんどである 6, 9, 10, 11, 12, 13, 14が，本症例では頸部・四肢屈側にも苔癬化を認めておらず，ADのコントロールは良好であったと考えられた。また齲歯や注射痕も認めず，当初侵入門戸は判然としなかったが，後に患者が新型コロナウイルス感染症の流行に伴いアルコールを用いて頻回に手指消毒を行うようになり，手指の皮膚に乾燥を自覚していたことと手指の乾燥と亀裂を認めたことから，指尖部の皮膚損傷が侵入門戸となり，同側の前腕，肘に膿瘍形成をし，敗血症に至った可能性が考えられた。一方で下肢にも入院時に紅斑を認めたが，皮下膿瘍や，足趾・爪辺縁含め外傷痕も認められなかった。IEの皮疹として結節性紅斑が特異的との報告もあり 7，紅斑の存在にも留意が必要と考える。 ADでは，炎症が軽快して一見正常に見える皮膚も，組織学的には炎症細胞が残存し，再び炎症を引き起こしやすい状態にあることが多いといわれており 8，さらに手指消毒によりADが増悪する可能性も示唆されている 9ことからADの既往がある患者においては，重篤な感染のリスクがあることを念頭に入れておく必要がある。 2つ目は肺動脈弁にIEを発症したことである。孤立性肺動脈弁IEはIE全体の1.5～2.0%と稀であるとされ 13，さらに過去にADを基礎疾患として肺動脈弁にIEを合併した報告例はない。右心系IEの要因として薬物常習，先天性心疾患，消化管術後などとされている 13が，本症例ではAD以外に特殊な既往歴はなくこれらの発症要因は認めなかった。本症例では，繰り返し施行していた心臓超音波検査において有意な所見は認めず，心不全も合併することなく経過しており，さらにCT検査においても右心系IEに合併するとされる肺化膿症や肺塞栓などの所見は認めず，肺動脈弁単独にIEを発症した理由は判然としなかった。本症例のように原因不明なものは過去の報告では30%あるともされており 14，稀ではあるが肺動脈弁にIEが発生することにも注意が必要であると考える。 本症例では手術を選択しなかったが，欧州心臓病学会会議のガイドラインに基づく右心系IEにおける手術考慮例は，①真菌などの治療抵抗性の病原体が原因である，②適切な抗菌薬治療を行っても7日以上血液培養陽性が続く，③三尖弁の疵贅が20mmを超え，反復性肺塞栓を認める，④内科的治療に対しての反応不良であり重度三尖弁逆流による右心不全を来した場合，とされる。本症例では持続菌血症は8日以内に陰転化しており弁破壊・逆流増悪も認められなかったことや治療に対する反応が良好であり疣贅の増大も認めなかったため手術を選択せず内科的に加療を継続した。 さらに本症例では経食道超音波検査を繰り返し施行したにもかかわらず，初期に疣贅を確認できず肺動脈弁IEと診断したのは入院33日目であった。本症例では熱源の精査目的に施行した造影CT検査により肺動脈弁に疣贅を偶発的に疑い，確定診断に至った。IEの診断においては，経食道心臓超音波検査が優れているとされている 16が，早期の病変描出は困難とされ，臨床的に疑われる場合は3～7日おきに繰り返し施行することが推奨されている 17。本症例においては，入院2日目，15日目に経食道心臓超音波検査を施行していたが有意な所見は認めなかった。後方視的に振り返ると臨床的に疑い，15日目以降も検査を繰り返し施行していればより早期に診断に至った可能性はあるが，皮下・筋膜膿瘍も形成しており全身性の多発小膿瘍形成が菌血症の長期化につながりIEを来した可能性も考慮される。 ADの既往のある菌血症症例においては当初疣贅を確認できなくても，IEの可能性を念頭に入れて評価を丹念に繰り返していく必要がある。 アトピー性皮膚炎の既往がある患者における持続菌血症は血管内病変として肺動脈弁領域も考慮し丹念に評価をする必要がある 利益相反はない。

Sepsis with Staphylococcus aureus in child with selective IgA deficiency and SARS-CoV-2 infection - case presentation

Sepsis is one of the most severe pediatric infectious diseases that can progress to serious complications or even death without specialized treatment. It often evolves as a complication of a viral illness or against the background of a depressed host immune terrain. SARS-CoV-2 infection is a self-limiting viral infection in children, which is rarely complicated, especially in immunocompromised or co-morbid individuals. In this paper we present a clinical case of a 1 year and 2 months old child admitted to the Pediatric Infectious Diseases Clinical Department IX of the National Institute of Infectious Diseases “Prof. Dr. Matei Bals” with the diagnosis of SARS-CoV-2 infection. The positive diagnosis was established on epidemiological data (parents with SARS-CoV-2 infection), suggestive clinical picture (fever, inappetence, vomiting) and confirmed by RT-PCR. 72 hours after admission, with favorable clinical evolution, the child presented again fever and chills. Laboratory investigations show leukocytosis with neutrophilia, inflammatory syndrome present and, in nasal exudate and blood culture, staphylococcus aureus MSSA is isolated. Also, immunogram shows low IgA level, the rest of the laboratory tests are within normal limits. Antibiotic treatment was instituted, symptomatic hydroelectrolytic and acid-base rebalancing infusions with favorable evolution. The case presented shows that although SARS-CoV-2 infection is often a mild condition in children, it can evolve severely, especially in immunosuppressed individuals with comorbidities. The presented child was not known to have selective IgA immunodeficiency, which probably in combination with COVID-19 induced immunosuppression, favored the development of sepsis.

“One-by-One, TB Took Everything Away From Me”: A Photovoice Exploration of Stigma in Women with Drug-Resistant Tuberculosis in Mumbai

Stigma related to drug-resistant tuberculosis (DR-TB), one of the world's most severe infectious diseases, is a major barrier to TB elimination particularly for women living in settings of gender inequity. Drawing on the participatory action research (PAR) framework of photovoice, we explored lived experiences of DR-TB stigma among nine affected women in Mumbai, India. Consenting women took, shared, and contributed to the critical interpretation of 37 non-identifying images and associated narratives with one another and with PAR researchers. The study surfaced vivid, untold stories of trauma and life-altering encounters with enacted, anticipated, and internal stigma, that were characterized by loss (of self, voice, status, mobility), abuse (mental, social) and deep internal distress (shame, isolation, suffocation, peril). The study also revealed how stigmatized women found means to build resilience and resist the impacts of stigma. We further witnessed the building of their collective resilience through study participation. Photovoice proved to be a uniquely compelling method of data capture and interpretation, with potential to develop meaningful engagement and solidarity among women affected by DR-TB.

Proteins in pregnant swine serum promote the African swine fever virus replication: an iTRAQ-based quantitative proteomic analysis

African swine fever (ASF) is a severe infectious disease caused by the African swine fever virus (ASFV), seriously endangering the global pig industry. ASFV possesses a large genome, strong mutation ability, and complex immune escape mechanisms. Since the first case of ASF was reported in China in August 2018, it has had a significant impact on social economy and food safety. In the present study, pregnant swine serum (PSS) was found to promote viral replication; differentially expressed proteins (DEPs) in PSS were screened and identified using the isobaric tags for relative and absolute quantitation technology and compared with those in non-pregnant swine serum (NPSS). The DEPs were analyzed using Gene Ontology functional annotation, Kyoto Protocol Encyclopedia of Genes and Genome pathway enrichment, and protein–protein interaction networks. In addition, the DEPs were validated via western blot and RT-qPCR experiments. And the 342 of DEPs were identified in bone marrow-derived macrophages cultured with PSS compared with the NPSS. The 256 were upregulated and 86 of DEPs were downregulated. The primary biological functions of these DEPs involved signaling pathways that regulate cellular immune responses, growth cycles, and metabolism-related pathways. An overexpression experiment showed that the PCNA could promote ASFV replication whereas MASP1 and BST2 could inhibit it. These results further indicated that some protein molecules in PSS were involved in the regulation of ASFV replication. In the present study, the role of PSS in ASFV replication was analyzed using proteomics, and the study will be provided a basis for future detailed research on the pathogenic mechanism and host interactions of ASFV as well as new insights for the development of small-molecule compounds to inhibit ASFV.

Serum levels of p-tau181 in patients with Parkinson’s disease

Background: Parkinson’s disease (PD) is the second most common neurodegenerative disease. Evidence has shown that phosphorylated tau-181 (p-tau181) is involved in the pathological process of PD. The goal of this study was to investigate the changes of serum phosphorylated Microtubule-associated protein tau at threonine-181 in patients with Parkinson's disease and it's correlation with disease severity, cognitive impairment and prognosis. Methods: A total of 40 patients with primary Parkinson's disease who were hospitalized or outpatient in the First Affiliated Hospital of Chongqing Medical University from July 2021 to February 2022 were selected as the study subjects. Patients with secondary Parkinson's disease, Parkinson's syndrome, stroke, Alzheimer's disease, craniocerebral surgery or trauma, severe systemic or infectious diseases, local or systemic infectious diseases, motor neurone disease or other central nervous system diseases were excluded. In addition, 35 healthy subjects with similar age and gender matching were selected as the healthy control group. Age, gender, course of disease, Hoehn-Yahr (H-Y) scale, Unified Parkinson's Disease Scale (UPDRS), and MoCA score were recorded in the Parkinson's disease group. According to the H-Y scale, PD group was divided into PD patients in the advanced stage (H-Y≤2.5, n=16) and PD patients in the advanced stage (H-Y>2.5, n=24). Six months after blood sample collection, we assessed the H-Y rating and UPDRS score in the Parkinson's group again by telephone follow-up. Those with decreased or unchanged H-Y rating or total UPDRS score were divided into good prognosis group (n=25), and those with increased H-Y rating or total UPDRS score were divided into poor prognosis group (n=14). The serum p-tau181 concentration of all subjects was detected and compared by double-antibody sandwich enzyme-linked immunosorbent assay (ELISA), and the correlation between serum p-tau181 level and UPDRS score, MoCA score and prognosis of Parkinson's disease patients was analyzed. Results: Compared with HC, serum p-tau181 concentration in PD patients were higher, but not statistically significant (1.01[0.28-2.63]vs 0.53[0.04-3.72]ug/mL, P=0.55, P>0.05). There was no significant difference in p-tau181 concentration between PD patients in early stage and PD patients in advanced stage (P=0.80 P>0.05), and no significant difference in p-tau181 level between PD patients with cognitive impairment, PD patients with normal cognition and HC patients (P=0.63, p>0.05). P-tau181 was not significantly correlated with disease duration (r=-0.14, P=0.37, P>0.05), UPDRS score (r=0.02, P=0.89, P>0.05), and MoCA score (r= 0.16, P=0.32, P > 0.05). There was no significant difference in serum P-tau181 expression between good prognosis group and poor prognosis group (P=0.74, P > 0.05). Conclusions: Serum expression of p-tau181 increased in PD patients, but no statistical difference was observed, and no clear correlation was found between p-tau181 and disease severity and cognitive impairment. Serum p-tau181 level in PD patients has no significant prognostic significance.

Specialized palliative care for hospitalized patients with SARS-CoV-2 infection: an analysis of the LEOSS registry

PurposeSymptom control for patients who were severely ill or dying from COVID-19 was paramount while resources were strained and infection control measures were in place. We aimed to describe the characteristics of SARS-CoV-2 infected patients who received specialized palliative care (SPC) and the type of SPC provided in a larger cohort.MethodsFrom the multi-centre cohort study Lean European Open Survey on SARS-CoV-2 infected patients (LEOSS), data of patients hospitalized with SARS-CoV-2 infection documented between July 2020 and October 2021 were analysed.Results273/7292 patients (3.7%) received SPC. Those receiving SPC were older and suffered more often from comorbidities, but 59% presented with an estimated life expectancy > 1 year. Main symptoms were dyspnoea, delirium, and excessive tiredness. 224/273 patients (82%) died during the hospital stay compared to 789/7019 (11%) without SPC. Symptom control was provided most common (223/273; 95%), followed by family and psychological support (50% resp. 43%). Personal contact with friends or relatives before or during the dying phase was more often documented in patients receiving SPC compared to patients without SPC (52% vs. 30%).ConclusionIn 3.7% of SARS-CoV-2 infected hospitalized patients, the burden of the acute infection triggered palliative care involvement. Besides complex symptom management, SPC professionals also focused on psychosocial and family issues and aimed to enable personal contacts of dying patients with their family. The data underpin the need for further involvement of SPC in SARS-CoV-2 infected patients but also in other severe chronic infectious diseases.

Effects of intravenous immunoglobulin on the negatively transformed subpopulations of neutrophilic granulocytes in newborns with congenital pneumonia and neonatal sepsis

Today, the diagnosis and treatment of severe infectious and inflammatory diseases in newborns, e.g., congenital pneumonia (CP) and neonatal sepsis (NS), present difficult problems. Searching sensitive and specific severity markers of bacterial inflammatory process as well as early and effective treatment are crucial for the outcome and prognosis of these life-threatening diseases. The aim of our study was to assess the effects of intravenous immunoglobulin (IVIG) injections on the negatively transformed subpopulations of neutrophilic granulocytes (NG) СD64-CD16+СD32+СD11b+, СD64+CD16+СD32+СD11b+ and evaluation of their functional activity in newborns with CP and NS. We have observed 38 full-term newborn patients. Group 1 included 19 infants with CP, including 11 children who received conventional therapy and IVIG (group 1.1), and 8 children treated at conventional protocols (group 1.2). Group 2 included 19 children with NS, including 12 children who underwent conventional therapy and IVIG treatment (group 2.1), and 7 children who were subject to conventional therapy (group 2.2). The comparison group consisted of 22 healthy full-term newborns. Testing of NG population included the following parameters: counting the numbers of NG subpopulations which simultaneously expressed CD11b CD64, CD32, CD16, as well as their phenotypic patterns, with regard of the receptor expression density (MFI) using flow cytometric techniques. Moreover, we determined phagocytic and microbicidal activity of the granulocytes. We have revealed negative transformation of СD64-CD16+СD32+СD11b+ and СD64+CD16+СD32+СD11b+ subpopulations of neutrophilic granulocytes in newborns with CP and NS, The diagnostic significance of increased СD64+CD16+СD32+СD11b+NG subpopulation was more pronounced with increasing severity of bacterial infection and inflammatory process, i.e., 18.7-fold in CP, 52.3-fold in NS, along with predominant decrease in expression of appropriate membrane receptors. These phenotypic changes were associated with impaired phagocytic and killing activity of NG. The effect of IVIG on the impaired mechanisms of antibacterial immunity is associated not only with alleviation of IgG deficiency, but also with positive remodeling of negatively transformed subpopulations of СD64-CD16+СD32+СD11b+NG and СD64+CD16+СD32+СD11b+NG, improved effector functions of NG, especially in cases of CP. Thus, following IVIG treatment, a reduced number of СD64-CD16+СD32+СD11b+NG subpopulations was fully recovered in CP, while it increased 1.5 times in NS, and the content of diagnostically significant СD64+CD16+СD32+СD11b+NG subpopulation showed a significantly decrease, both in CP (2-fold) and in NS (2.6-fold). However, this index remained higher than the content of this subpopulation in healthy newborns. At the same time, we have noted the restorative or modulatory effects by changing density of trigger molecules in NG subpopulations. Limitation of the negative NG transformation in their functionally significant subpopulations in newborns with CAP and NS was accompanied by positive clinical effects, i.e., optimization of antibiotic therapy, reduced duration of treatment, and improved mortality rates.

Variation in ERAP2 has opposing effects on severe respiratory infection and autoimmune disease

ERAP2 is an aminopeptidase involved in immunological antigen presentation. Genotype data in human samples from before and after the Black Death, an epidemic due to Yersinia pestis, have marked changes in allele frequency of the single-nucleotide polymorphism (SNP) rs2549794, with the T allele suggested to be deleterious during this period, while ERAP2 is also implicated in autoimmune diseases. This study explored the association between variation at ERAP2 and (1) infection, (2) autoimmune disease, and (3) parental longevity. Genome-wide association studies (GWASs) of these outcomes were identified in contemporary cohorts (UK Biobank, FinnGen, and GenOMICC). Effect estimates were extracted for rs2549794 and rs2248374, a haplotype tagging SNP. Additionally, cis expression and protein quantitative trait loci (QTLs) for ERAP2 were used in Mendelian randomization (MR) analyses. Consistent with decreased survival in the Black Death, the T allele of rs2549794 showed evidence of association with respiratory infection (odds ratio; OR for pneumonia 1.03; 95% CI 1.01-1.05). Effect estimates were larger for more severe phenotypes (OR for critical care admission with pneumonia 1.08; 95% CI 1.02-1.14). In contrast, opposing effects were identified for Crohn disease (OR 0.86; 95% CI 0.82-0.90). This allele was shown to associate with decreased ERAP2 expression and protein levels, independent of haplotype. MR analyses suggest that ERAP2 expression may be mediating disease associations. Decreased ERAP2 expression is associated with severe respiratory infection with an opposing association with autoimmune diseases. These data support the hypothesis of balancing selection at this locus driven by autoimmune and infectious disease.

Structure and Antibiotic Resistance of the Main Causative agents of Infections Associated with the Provision of Medical care

Relevance. The problem of healthcare-associated infections (HCAI) is becoming increasingly important in epidemiological, social and economic terms. The most serious threat to hospital patients is multidrug-resistant Gram-negative organisms such as Pseudomonas aeruginosa and Klebsiella pneumoniae. The purpose of the study was to determine the etiological structure and sensitivity to antimicrobial agents of infectious agents associated with the provision of medical care in a children's multidisciplinary hospital. Materials and methods. The strains used in the work were obtained from patients aged from one to 15 years with severe infectious diseases. Additionally, swabs were taken from environmental objects. Bacteriological identification of selected strains was performed using standardized bacteriological algorithms and MALDI-TOF direct protein profiling of non-spore-forming microorganisms. Results. P. aeruginosa and K. pneumoniae were identified as the main causative agents of HAI with multiple resistance to AMPs in the children's multidisciplinary hospital, the source of which was mainly the respiratory tract. Multiple resistance to AMP was higher in K. pneumoniae, 38.9% of the studied isolates showed resistance to four drugs simultaneously. P. aeruginosa in 23.1% of cases was resistant to one AMP, in 15.4% - to two, four and seven AMPs. Conclusion. For a reasonable choice and optimization of antibacterial treatment of hospital patients, it is necessary to take into account the fact of wide circulation of hospital strains. Systematic monitoring of the constantly changing microbiological landscape of hospitals based on microbiological monitoring data and determining the levels of resistance to antimicrobial chemotherapy drugs will help reduce the risk and prevent the development of infections associated with healthcare.

The Establishment of the Concept of Shu Yi and Its Significance in the History of Knowledge

Plague is one of the severe infectious diseases which has had a huge impact on human society throughout history. Although there is abundant research on the disease, few studies focus on the concept of plague itself. It is generally believed that Shu Yi was first coined by Chinese doctors in the late 19th century, and it was closely related to the introduction of new medicine. This statement is not accurate, because plague was prevalent in Yunnan and Guangdong provinces in the late Qing Dynasty. At that time, people had already recognized the relationship between the outbreak of plague and the death of rats, and gradually named the epidemic disease as Shu Yi. This name was used by literati and doctors by coincidence. As the epidemic became more and more serious, more related works were widely disseminated, and Shu Yi changed from a folk name to a formal name. Later, with the help of the government’s active introduction of modern health and epidemic prevention mechanisms and the implementation of rodent control measures, Shu Yi became more popular and gradually recognized by all walks of society. The emergence and prevalence of Shu Yi created the history of zoonosis in China, and thus formed a new paradigm of naming human epidemics after related animal names.

African Swine Fever Virus MGF505-7R Interacts with Interferon Regulatory Factor 9 to Evade the Type I Interferon Signaling Pathway and Promote Viral Replication.

African swine fever (ASF) is an acute and severe infectious disease caused by the ASF virus (ASFV). The mortality rate of ASF in pigs can reach 100%, causing huge economic losses to the pig industry. Here, we found that ASFV protein MGF505-7R inhibited the beta interferon (IFN-β)-mediated Janus-activated kinase-signal transducer and activation of transcription (JAK-STAT) signaling. Our results demonstrate that MGF505-7R inhibited interferon-stimulated gene factor 3 (ISGF3)-mediated IFN-stimulated response element (ISRE) promoter activity. Importantly, we observed that MGF505-7R inhibits ISGF3 heterotrimer formation by interacting with interferon regulatory factor 9 (IRF9) and inhibits the nuclear translocation of ISGF3. Moreover, to demonstrate the role of MGF505-7R in IFN-I signal transduction during ASFV infection, we constructed and evaluated ASFV-ΔMGF505-7R recombinant viruses. ASFV-ΔMGF505-7R restored STAT2 and STAT1 phosphorylation, alleviated the inhibition of ISGF3 nuclear translocation, and showed increased susceptibility to IFN-β, unlike the parental GZ201801 strain. In conclusion, our study shows that ASFV protein MGF505-7R plays a key role in evading IFN-I-mediated innate immunity, revealing a new mode of evasion for ASFV. IMPORTANCE ASF, caused by ASFV, is currently prevalent in Eurasia, with mortality rates reaching 100% in pigs. At present, there are no safe or effective vaccines against ASFV. In this study, we found that the ASFV protein MGF505-7R hinders IFN-β signaling by interacting with IRF9 and inhibiting the formation of ISGF3 heterotrimers. Of note, we demonstrated that MGF505-7R plays a role in the immune evasion of ASFV in infected hosts and that recombinant viruses alleviated the effect on type I IFN (IFN-I) signaling and exhibited increased susceptibility to IFN-β. This study provides a theoretical basis for developing vaccines against ASFV using strains with MGF505-7R gene deletions.

The emerging threat of methicillin-resistant Staphylococcus aureus (MRSA) clone ST22-PT, carrying both Panton-Valentine leucocidin and toxic shock syndrome toxin 1 genes.

Some MRSA strains produce Panton-Valentine leucocidin (PVL) and/or toxic shock syndrome toxin 1 (TSST-1), which are associated with severe infectious diseases. Although PVL- or TSST-1-positive strains have been isolated worldwide, strains carrying both PVL and TSST-1 genes are rare and sporadic. The objective of this study was to characterize these strains from Japan. A total of 6433 MRSA strains isolated in Japan between 2015 and 2021 were analysed. Molecular epidemiological and comparative genomic analyses were conducted on PVL- and TSST-1-positive MRSA strains. A total of 26 strains from 12 healthcare facilities were PVL positive and TSST-1 positive, and all were classified as clonal complex (CC) 22. These strains exhibited similar genetic features to each other and were named as ST22-PT according to a previous report. Twelve and one of the ST22-PT strains were identified in patients with deep-seated skin infections and toxic shock syndrome-like symptoms, which are typical clinical features of PVL-positive and TSST-1-positive Staphylococcus aureus, respectively. Whole-genome comparative analysis revealed that the ST22-PT strains were highly similar to PVL- and TSST-1-positive CC22 strains isolated in several countries. Evaluation of the genome structure showed that ST22-PT possessed ΦSa2 harbouring PVL genes and a unique S. aureus pathogenicity island harbouring the TSST-1 gene. ST22-PT strains have recently emerged from several healthcare facilities in Japan, and ST22-PT-like strains have been identified in several countries. Our report highlights that the risk of international spread of PVL- and TSST-1-positive MRSA clone ST22-PT needs to be further investigated.

PI3K–Akt pathway-independent PIK3AP1 identified as a replication inhibitor of the African swine fever virus based on iTRAQ proteomic analysis

African swine fever (ASF) is a severe infectious disease that has a high global prevalence. The fatality rate of pigs infected with ASF virus (ASFV) is close to 100%; in the absence of a safe and reliable commercial vaccine, this poses a threat to the global pig industry and public health. To better understand the interaction of ASFV with its host, isobaric tags for relative and absolute quantitation combined with liquid chromatography-mass spectrometry was used to conduct quantitative proteomic analysis of bone marrow-derived macrophage cells infected with ASFV. Overall, 4579 proteins were identified; 286 of these were significantly upregulated and 69 were significantly downregulated after ASFV infection. Gene Ontology, Kyoto Encyclopedia of Genes and Genomes, and protein-protein interaction network analyses were used to obtain insights into the dynamics and complexity of the ASFV-host interaction. In addition, immunoblotting revealed that the expression of PIK3AP1, RNF114, and FABP5 was upregulated and that of TRAM1 was downregulated after ASFV infection. Overexpression of PIK3AP1 and RNF114 significantly inhibited ASFV replication in vitro, but the suppressive effect of PIK3AP1 on ASFV replication was independent of the PI3K-Akt pathway. Further studies confirmed that ASFV MGF360-9L interacts with PIK3AP1 to reduce its protein expression level. Moreover, LY294002, an inhibitor of the PI3K-Akt pathway, inhibited ASFV replication, indicating the importance of the PI3K-Akt pathway in ASFV infection. This study identified the network of interactions between ASFV and host cells and provides a reference for the development of anti-ASFV strategies and for studying the potential mechanisms and pathogenesis of ASFV infection.