Infectious Medicine最新文献

Mediterranean spotted fever (MSF) has been diagnosed clinically in the Crimean Peninsula since the 1930s. We describe the recent illness of an elderly patient from Crimea who had developed a classic triad of MSF symptoms consisting of fever, maculopapular rash, and eschar. Clinical diagnosis of rickettsiosis was confirmed using real-time PCR and sequencing of 4 Rickettsia protein genes. The strain causing clinical illness was characterized as Rickettsia conorii subspecies conorii Malish 7. This report corroborates the utility of eschar swab material as a source of DNA for PCR-based diagnostics that enables timely patient treatment and management.

Hemophagocytic lymphohistiocytosis (HLH) syndrome is an uncontrolled activation of macrophages, causing multiorgan dysfunction. The prognosis depends on the cause and the delay of diagnosis and treatment. Several infections can cause HLH, including rickettsia, a gram-negative bacterium. The diagnosis of rickettsia is based on clinical signs, including fever, headache, rash and sometimes tick bite site. The importance of an early diagnosis of rickettsia is the key. We present a case of rickettsia infection complicated with severe HLH occurring in a 21-year-old woman. The diagnosis was confirmed by serology 4 weeks after admission. She was treated with immunoglobulin, corticosteroids, and doxycycline with a favorable outcome.

Pseudomonas aeruginosa is an aerobic Gram-negative rod-shaped bacterium with a comparatively large genome and an impressive genetic capability allowing it to grow in a variety of environments and tolerate a wide range of physical conditions. This biological flexibility enables the P. aeruginosa to cause a broad range of infections in patients with serious underlying medical conditions, and to be a principal cause of health care associated infection worldwide. The clinical manifestations of P. aeruginosa include mostly health care associated infections and community-acquired infections. P. aeruginosa possesses an array of virulence factors that counteract host defence mechanisms. It can directly damage host tissue while utilizing high levels of intrinsic and acquired antimicrobial resistance mechanisms to counter most classes of antibiotics. P. aeruginosa co-regulates multiple resistance mechanisms by perpetually moving targets poses a significant therapeutic challenge. Thus, there is an urgent need for novel approaches in the development of anti-Pseudomonas agents. Here we review the principal infections caused by P. aeruginosa and we discuss novel therapeutic options to tackle antibiotic resistance and treatment of P. aeruginosa infections that may be further developed for clinical practice.

Background

HIV-1 Vpu acts by counteracting the tethering function of tetherin and resulting in the release of HIV-1 virion. Disrupting Vpu-tetherin interactions may provide a promising new target for antiretroviral therapy.

Methods

Polypeptides that covered the amino acid sequence on the interface of Vpu-tetherin complex were designed. Phenotypic susceptibilities and cellular toxicities to the polypeptides were measured. The mechanisms of the anti-HIV-1 polypeptides were determined by the Western blot analysis and laser confocal scanning. Seven 20-mer polypeptides from wild-type Vpu amino acid sequence were designed.

Results

We report the design and identification of 3 novel anti-HIV-1 polypeptides that derived from Vpu sequence which can efficiently inhibit HIV-1 infection. A pilot mechanism study showed that the active polypeptide could counteract Vpu-mediated tetherin downregulation. Laser confocal image scanning study showed that the polypeptides bound on the cell surface with a receptor specific binding manner, which may target tetherin that expressed on cell surface.

Conclusion

Our work provided first evidence that counteracting Vpu-mediated tetherin downregulation could be a target for novel anti-HIV-1 drug design. Future works to provide direct evidence of inhibitors interact with tetherin at atomic resolution and the development of small molecules inhibitors targeting Vpu-tetherin interactions may open a new avenue for novel antiretroviral therapy.

In 2022–2023, a global outbreak of Mpox was reported especially in nonendemic countries. We report the first laboratory-confirmed neonatal case of Mpox infection complicated by bronchopneumonia in Sri Lanka.

Background

West Nile virus is a severe zoonotic pathogen that can cause severe central nervous system symptoms in humans and horses, and is fatal for birds, chickens and other poultry. With no specific drugs or vaccines available, antibody-based therapy is a promising treatment. This study aims to develop neutralizing antibodies against West Nile virus and assess their cross-protective potential against Japanese encephalitis virus.

Methods

Monoclonal antibodies against WNV and JEV were isolated by hybridoma technology. The therapeutic efficacy of these antibodies was evaluated using a mouse model, and a humanized version of the monoclonal antibody was generated for potential human application.

Results

In this study, we generated eight monoclonal antibodies that exhibit neutralizing activity against WNV. Their therapeutic effects against WNV were validated both in vivo and in vitro. Among these antibodies, C9-G11-F3 also exhibited cross-protective activity against JEV. We also humanized the antibody to ensure that it could be used for WNV infection treatment in humans.

Conclusion

This study highlights the importance of neutralizing antibodies as a promising approach for protection against West Nile virus infection and suggests their potential utility in the development of therapeutic interventions.

Background

Strongyloidiasis, a neglected disease caused by intestinal nematodes of the genus, is endemic to tropical and subtropical areas such as Vietnam. Morphological methods only identify the genus, while DNA-molecular techniques are susceptible in Strongyloides spp. detection. The study aims to determine the prevalence of dominant Strongyloides species among the population in Duc Hoa district, Long An, Vietnam.

Methods

A cross-sectional study used 1190 stool specimens collected from July 2017 to November 2018. All samples were transported within 2 h, stored at 2–8°C, and processed within 48 h for microscopy smear and culture at the Laboratory of Medical Parasitology, Pham Ngoc Thach University of Medicine (PNT). Then all positive samples with the above 2 methods were verified by real-time PCR technique. Real-time PCR amplification was conducted at the Laboratory of Molecular Biology, PNT.

Results

Direct microscopy and modified Harada-Mori culture detected Strongyloides spp. larvae in 79/1190 samples (6.6%). About 94.2% of the DNA samples were Strongyloides stercoralis, 2.9% were co-infections with Strongyloides ratti and S. stercoralis, and 2.9% were patients with S. ratti. The identity of 12/14 sequences was confirmed as S. stercoralis with a high level of similarity (91.3%–100%) and over 98% for S. ratti.

Conclusion

DNA-molecular techniques and sequence analysis are highly suitable for identifying Strongyloides species isolated from stool samples. It is remarkable evidence of the presence of zoonosis S. ratti disease in human, not just the known S. stercoralis. It is likely to result in a certain proportion of people being infected by this animal-borne infectious pathogen.

Dengue is amongst the most prevalent viral diseases which globally affects millions of individuals annually and renders billions at risk, particularly in tropical and sub-tropical nations. WHO estimated 100–400 million infections each year and reported 4.2 million active cases in 2019 worldwide. The infection is caused by arthropod-transmitted dengue virus which is known to have 5 serotypes (DENV1-5). Most of the cases show mild clinical symptoms; though others may develop severe forms viz; dengue hemorrhagic fever and dengue shock syndrome. Though limited literature suggests the population-specific genetic influence on susceptibility and the clinical course of dengue; the genetic propensity of dengue is largely unknown in most ethnicities. In this context, the human leukocyte antigen (HLA) system represents the most polymorphic region of the human genome and is crucial for the initiation of an appropriate immune response. In most of the genome-wide association studies, the HLA complex is the most significantly linked genetic region with susceptibility or protection towards various infectious and noninfectious diseases. Killer immunoglobulin-like receptors represent another highly variable system present on the surface of natural killer (NK) cells which regulate the activity of NK cells through interactions with their cognate HLA ligands. It is conceivable that the interaction of HLA-Killer immunoglobulin-like receptors systems influences the host susceptibility towards dengue infection as well the disease outcome. Here we attempt to review these parameters in dengue infection and disease outcome. Further detailed investigations are warranted towards the identification of novel susceptibility markers and targeted therapeutic interventions.

Background

Severe fever with thrombocytopenia syndrome (SFTS) is an emerging hemorrhagic fever caused by a tick-borne bunyavirus SFTSV with case fatality up to 30%. The reactivation of Epstein-Barr virus (EBV) has been proven to occur in individuals with various immune suppression conditions.

Methods

Here, we diagnosed 22 SFTSV infected patients with PCR in a hospital in Shandong Province, China in 2020. To understand the consequences of SFTSV infection leading to EBV reactivation, we examined EBV reactivation in SFTSV-infected patients with PCR and RT-PCR.

Results

We found that EBV was reactivated in 18.2% (4/22) of SFTS patients, suggesting that EBV reactivation is common in SFTS patients. Compared with SFTS patients without EBV reactivation, SFTS patients with EBV-reactivation had a significantly lower median level of serum albumin (32.45 g/L vs. 26.95 g/L, p = 0.03) and a significantly higher median number of urine red blood cells (0 cells/μL vs. 9 cells/μL, p = 0.04).

Conclusion

SFTS infection can reactivate EBV in patients, which may make the clinical condition of patients worsen.

Mpox (monkeypox) virus (MPXV), which causes a mild smallpox-like disease, has been endemic in Africa for several decades, with sporadic cases occurring in other parts of the world. However, the most recent outbreak of mpox mainly among men that have sex with men has affected several continents, posing serious global public health concerns. The infections exhibit a wide spectrum of clinical presentation, ranging from asymptomatic infection to mild, severe disease, especially in immunocompromised individuals, young children, and pregnant women. Some therapeutics and vaccines developed for smallpox have partial protective and therapeutic effects against MPXV historic isolates in animal models. However, the continued evolution of MPXV has produced multiple lineages, leading to significant gaps in the knowledge of their pathogenesis that constrain the development of targeted antiviral therapies and vaccines. MPXV infections in various animal models have provided a central platform for identification and comparison of diseased pathogenesis between the contemporary and historic isolates. In this review, we discuss the susceptibility of various animals to MPXV, and describe the key pathologic features of rodent, rabbit and nonhuman primate models. We also provide application examples of animal models in elucidating viral pathogenesis and evaluating effectiveness of vaccine and antiviral drugs. These animal models are essential to understand the biology of MPXV contemporary isolates and to rapidly test potential countermeasures. Finally, we list some remaining scientific questions of MPXV that can be resolved by animal models.