- Volume 2, Issue 7, 2020

Introduction. The diagnosis of tuberculous meningitis (TBM) is a major global health concern due to its protean nature. There is a need to identify better biomarkers for the rapid and definitive diagnosis of TBM. Lipids have been poorly explored as diagnostic markers in TBM.

Aim. Non-polar lipids (NPL) and mycobacterial sonicate extract (MTSE) antigens were assessed for diagnosis of Mycobacterium tuberculosis .

Methodology. A total of 110 cerebrospinal fluid samples were categorized as confirmed, suspected and non-TBM cases according to clinical presentation and laboratory investigations, which were further analysed by NPL and MTSE ELISA.

Results. The sensitivity and specificity of the NPL ELISA were 39.6 and 96 %, respectively, whereas the MTSE ELISA was 17 % sensitive and 92 % specific. The combination of the NPL and MTSE ELISA test was superior to these tests alone, with sensitivity and specificity of 43 and 88 %, respectively.

Conclusion. This combination may be useful as an adjunct in the laboratory diagnosis of TBM. However, future studies in different settings among different populations, such as those with human immunodeficiency virus co-infection, are desirable to explore the full potential of biomarkers.

Quorum sensing is known to regulate bacterial virulence, and the accessory gene regulator (agr) loci is one of the genetic loci responsible for its regulation. Recent reports examining Clostridioides difficile show that two agr loci, agr1 and agr2, regulate toxin production, but the diversity of agr loci and their epidemiology is unknown. In our study, in silico analysis was performed to research genetic diversity of agr, and C. difficile isolates from clinical samples underwent multilocus sequence typing (MLST) and PCR analysis of agr loci. To reveal the distribution of agr among different strains, phylogenetic analysis was also performed. In our in silico analysis, two different subtypes, named agr2R and agr2M, were found in agr2, which were previously reported. PCR analysis of 133 C . difficile isolates showed that 131 strains had agr1, 61 strains had agr2R, and 26 strains had agr2M; agr2R was mainly found in clade 1 or clade 2 organisms, whereas agr2M was only found in clade 4. With rare exception, agr1-negative sequence types (STs) belonged to clade C-Ⅰ and C-Ⅲ, and one clade 4 strain had agr2R. Our study revealed subtypes of agr2 not previously recognized, and the distribution of several agr loci in C. difficile . These findings provide a foundation for further functional and clinical research of the agr loci.

In this work we analysed the whole genome extended multilocus sequence typing (wgMLST) of four Pseudomonas aeruginosa strains that are characterized by being virulent despite having a defective Las quorum-sensing (QS) system, and compare them with the wgMLST of the PAO1 and PA14 type strains. This comparison was done to determine whether there was a genomic characteristic that was common to the strains with an atypical QS response. The analysed strains include two environmental isolates (ID 4365 isolated from the Indian Ocean, and M66 isolated from the Churince water system in Cuatro Ciénegas Coahuila, México), one veterinary isolate (strain 148 isolated from the stomach of a dolphin) and a clinical strain (INP43 that is a cystic fibrosis pediatric isolate). We determine that the six analysed strains have a core genome of 4689 loci that was used to construct a wgMLST-phylogeny tree. Using the cano-wgMLST_BacCompare software we found that there was no common genomic characteristic to the strains with an atypical QS-response and we identify ten loci that are highly discriminatory of the six strains’ phylogeny so that their MLST can reconstruct the wgMLST-phylogeny tree of these strains. We discuss here the nature of these ten highly discriminatory genes in the context of P. aeruginosa virulence and evolution.

Microbial species can act in synergy to circumvent environmental stress conditions and survive. In addition, biofilms are a serious public-health issue globally and constitute a clinical emergency. Infection persistence, increased morbidity and mortality, and antibiotic resistance are consequences of poly-microbial synergy. Due to inherited complexity and synergy between numerous species, newer antimicrobial agents of increased efficacy and tolerability are needed. In this unique medical case, a chronic (9 year) multi-bacterial scalp infection was differentially diagnosed from other inflammatory skin disorders by prolonged microbiological culture. The bacterial species found seem to have caused lesions of visible biofilm not documented previously in the medical literature. This complicated infection was treated successfully and rapidly with the combined topical application of the active halogen compounds N-chlorotaurine, N-bromotaurine and bromamine T, which is in contrast to the previous failed systemic and topical therapeutic approaches. This study strengthens the case for the use of active halogen compounds against multi-bacterial infections of the skin in the future, without the occurrence of resistance.

The studies of coronavirus disease 2019 (COVID-19) have mainly focused on epidemiological and clinical features of patients, but transmission dynamics of SARS-CoV-2 virus after patients have recovered is still poorly understood. Here we report a case with prolonged viral shedding of COVID-19 in Kaohsiung, Taiwan. This patient started to show myalgia and malaise in Wuhan, and the onset of the fever was on days 7–14 of the illness. All clinical and radiological results returned to normal after day 26, however, viral shedding was still evident 14 days later. Sequence analysis of the genome of the Taiwanese SARS-CoV-2 isolate from this patient reveals new mutations in viral replicase and ORF3a, indicating that COVID-19 evolves very quickly. Prolonged viral shedding and new mutations in the viral genome could potentially complicate the control of the COVID-19 pandemic.