Immunohistochemical diagnosis of human infectious diseases: a review

Highly sensitive and naked-eye detection of herpes simplex virus type 1 using LAMP- CRISPR/Cas12 diagnostic technology and gold nanoparticles

Herpes simplex virus type 1 (HSV-1) Keratitis (HSK) is a highly prevalent eye disease worldwide, characterized by lifelong recurrent episodes and a major risk of leading to blindness. Detecting HSV-1 promptly and accurately can initiate a timely and appropriate therapeutic regimen, minimizing tissue damage and preventing vision impairment. Currently, PCR is the most reliable method for identifying HSV-1, but its utilization for point-of-care (POC) HSV-1 detection is limited due to the need for sophisticated equipment, particularly in areas with limited resources. Here, we propose a new method for on-site HSV detection by using LAMP-Cas12 diagnostic technology and gold nanoparticles. This technique possesses comparable sensitivity to qPCR, and its detection results could be easily read and interpreted without the need for complex equipment. In detecting HSV in clinical tear specimens, this strategy achieved a 93.9 % consistency in positive detection and a 100 % consistency in negative detection compared to qPCR. Our strategy innovates the technique of current HSV-1 detections and is expected to play a crucial role in POC diagnosis of HSK in the future.

Old World Medieval Treponema pallidum Complex Treponematosis: A Case Report

BACKGROUND

Introduction of 1 Treponema pallidum complex pathogen in naive European populations following the return of Christopher Columbus' troops from Central America in 1493 is a central dogma in venereology.

METHODS

Among skeletal elements from the seventh or eighth century uncovered in Roquevaire, France, individual RS-1003 femur macroscopically suspected of having an infectious disease was investigated by means of paleoautoimmunohistochemistry, direct metagenomics, and paleoserology, along with 1 control femur from an apparently healthy individual (R-1003) and experimental negative controls.

RESULTS

RS-1003 femur showed infectious bone; paleoautoimmunohistochemistry of the lesions led to microscopic detection of a T. pallidum complex pathogen. Phylogenetic analyses comprising 71 T. pallidum complex-specific reads covering 2.37% of the T. pallidum subsp. pallidum reference genome sequence revealed an ancestral T. pallidum complex pathogen in the lesion. Paleoserology detecting T. pallidum-specific antigens confirmed positive serological findings in individual RS-1003. Individual R-1003 and the negative controls remained negative.

CONCLUSIONS

This case, predating by 8 centuries previous detections of T. pallidum complex treponematosis in Europe, indicated that European populations were not naive to these pathogens before the 1493 introduction of a Central American T. pallidum complex pathogen overwhelming the T. pallidum ones previously circulating in the Old World. These data break a century-old dogma in medical microbiology.

Agreement and differential use of laboratory methods for the detection and quantification of SARS-CoV-2 in experimentally infected animals

Rodents are widely used for the development of COVID-19-like animal models, the virological outcome being determined through several laboratory methods reported in the literature. Our objective was to assess the agreement between methods performed on different sample types from 342 rodents experimentally infected with SARS-CoV-2 (289 golden Syrian hamsters and 53 K18-hACE2 mice). Our results showed moderate agreement between methods detecting active viral replication, and that increasing viral loads determined by either RT-qPCR or infectious viral titration corresponded to increasing immunohistochemical scores. The percentage of agreement between methods decreased over experimental time points, and we observed poor agreement between RT-qPCR results and viral titration from oropharyngeal swabs. In conclusion, RT-qPCR and viral titration on tissue homogenates are the most reliable techniques to determine the presence and replication of SARS-CoV-2 in the early and peak phases of infection, and immunohistochemistry is valuable to evaluate viral distribution patterns in the infected tissues.

Infective Endocarditis in High-Income Countries

Infective endocarditis remains an illness that carries a significant burden to healthcare resources. In recent times, there has been a shift from Streptococcus sp. to Staphylococcus sp. as the primary organism of interest. This has significant consequences, given the virulence of Staphylococcus and its propensity to form a biofilm, rendering non-surgical therapy ineffective. In addition, antibiotic resistance has affected treatment of this organism. The cohorts at most risk for Staphylococcal endocarditis are elderly patients with multiple comorbidities. The innovation of transcatheter technologies alongside other cardiac interventions such as implantable devices has contributed to the increased risk attributable to this cohort. We examined the pathophysiology of infective endocarditis carefully. Inter alia, the determinants of Staphylococcus aureus virulence, interaction with host immunity, as well as the discovery and emergence of a potential vaccine, were investigated. Furthermore, the potential role of prophylactic antibiotics during dental procedures was also evaluated. As rates of transcatheter device implantation increase, endocarditis is expected to increase, especially in this high-risk group. A high level of suspicion is needed alongside early initiation of therapy and referral to the heart team to improve outcomes.