This article describes the nucleotide sequence of a porcine circovirus (PCV) which possesses a high degree of association with postweaning multisystemic wasting syndrome (PMWS), a newly described disease of young pigs. The DNA sequence of this PMWS-associated PCV (pmws PCV) has 68% homology with that of a previously published nonpathogenic strain of PCV. The strains appear to be closely related yet distinct from one another.

This is the first published report of a PCR assay for detecting porcine cytomegalovirus (PCMV), the causative agent of inclusion body rhinitis in pigs. The DNA to be tested was extracted directly from lungs and nasal scrapings of pigs with various clinical syndromes. Fifty-nine percent (74 of 126) of tested pigs with various clinical syndromes were found to be PCR positive for PCMV. It is hoped that veterinary diagnostic laboratories will benefit by using this PCR assay for routine testing and surveillance of PCMV in pigs.

Lon proteases are a family of ATP-dependent proteases involved in protein quality control, with a unique proteolytic domain and an AAA+ (ATPases associated with various cellular activities) module accommodated within a single polypeptide chain. They were classified into two types as either the ubiquitous soluble LonA or membrane-inserted archaeal LonB. In addition to the energy-dependent forms, a number of medically and ecologically important groups of bacteria encode a third type of Lon-like proteins in which the conserved proteolytic domain is fused to a large N-terminal fragment lacking canonical AAA+ motifs. Here we showed that these Lon-like proteases formed a clade distinct from LonA and LonB. Characterization of one such Lon-like protease from Meiothermus taiwanensis indicated that it formed a hexameric assembly with a hollow chamber similar to LonA/B. The enzyme was devoid of ATPase activity but retained an ability to bind symmetrically six nucleotides per hexamer; accordingly, structure-based alignment suggested possible existence of a non-functional AAA-like domain. The enzyme degraded unstructured or unfolded protein and peptide substrates, but not well-folded proteins, in ATP-independent manner. These results highlight a new type of Lon proteases that may be involved in breakdown of excessive damage or unfolded proteins during stress conditions without consumption of energy.

We aimed to compare the efficiency of the CapitalBioMycobacterium real-time polymerase chain reaction (PCR) detection test with the standard Xpert MTB/RIF assay for the diagnosis of tuberculous meningitis (TBM). Methods: We analyzed cerebrospinal fluid (CSF) from 163 patients with suspected TBM that were collected between January 1, 2018, and December 31, 2019. For both tests, we determined the sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and area under the curve (AUC). Next, we compared the diagnostic accuracy of the two techniques using clinical diagnosis as a reference standard. Results: The sensitivity, specificity, PPV, NPV, and AUC, of the CapitalBio Mycobacterium detection test were 48.5%, 100%, 100%, 29.6%, and 0.74, respectively, when used for the diagnosis of TBM. In comparison, the Xpert MTB/RIF assay returned values of 47.0%, 100%, 100%, 29.0%, and 0.74, respectively. Our analysis showed that the diagnostic accuracies of the CapitalBio Mycobacterium detection test and the Xpert MTB/ RIF assay were very similar; the accuracy of both tests for detecting mycobacteria was significantly higher than that associated with acidfast staining. Conclusions: The CapitalBio Mycobacterium real-time PCR detection test has moderate sensitivity and very high specificity for TBM; results are very similar to those generated by the Xpert MTB/RIF assay. We recommend that the CapitalBio PCR test should be used as an initial screening method for TB.

Background Nontuberculous mycobacteria (NTM) infection is similar to Mycobacterium tuberculosis (MTB) infection. Early clinical identification and differentiation of NTM and MTB infections continues to be a major challenge. Nucleic acid amplification tests (NAATs) have the ability to efficiently and rapidly detect pathogens and are widely used in mycobacterial infections. The objective of this study is to estimate the diagnostic accuracy of NAATs for NTM. Methods We will search candidate studies that assessing the accuracy of NAATs for diagnosis of NTM through PubMed, Embase and the Cochrane Library until May 2021. Studies with full text that meet the inclusion criteria will be included. Following a revised tool for Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2), two researchers will independently evaluate the study quality. The STATA software (version 15.0) will be used to carry out meta-analyses. When heterogeneity is observed, subgroup analyses and meta-regression analyses will be used to explore sources of heterogeneity. Sensitivity analyses will be used to check the robustness of analyses. Conclusion We hope that this study will provide meaningful evidence for the early and rapid diagnosis of NAATs for NTM, which will help to guide the treatment of NTM and improve the prognosis of patients.