Genome informatics and vaccine targets in Corynebacterium urealyticum using two whole genomes, comparative genomics, and reverse vaccinology

Novel configurations of type I-E CRISPR-Cas system in Corynebacterium striatum clinical isolates

Clustered regularly interspaced short palindromic repeats (CRISPR) are a prokaryotic adaptive immune system that, through Cas proteins, promote the degradation of foreign nucleic acids such as phages and plasmids. We analyzed 10 genomes of Corynebacterium striatum clinical isolates from a public hospital in Rio de Janeiro, Brazil, the most emergent multidrug-resistant Corynebacterium species. All isolates were submitted to antimicrobial susceptibility testing. The occurrence and diversity of the CRISPR system were investigated by bioinformatics tools. Our analysis revealed that the isolates exhibited type I-E gene arrangements, and 3 more multidrug-resistant isolates, alternative type I-E gene arrangements, showing a divergent gene arrangement within the cas operon. Phylogenetic analysis of the cas1 gene of this type I-E CRISPR-Cas system alternative arrangement, termed here type I-E', showed a cluster in a distinct clade of the type I-E CRISPR-Cas system. The systems' guanine-cytosine (GC) content is lower than the genomic DNA's GC content, and mobile genetic elements were found in some isolates near the CRISPR-Cas system. Most CRISPR spacers are unknown indicating that there is a reservoir of unexplored corynebacteriophages and plasmids. Some spacers showed perfect homologies with phage and plasmid sequences. Intact phage regions were found in 3 of our isolates, ranging from 9.1 to 43.8 kb, with regions showing similarity to Rhodococcus and Corynebacterium phages. Our results may contribute to research about the CRISPR-Cas system diversity in C. striatum, where there are no published data to date.

De Novo Long-Read Whole-Genome Assemblies and the Comparative Pan-Genome Analysis of Ascochyta Blight Pathogens Affecting Field Pea

Ascochyta Blight (AB) is a major disease of many cool-season legumes globally. In field pea, three fungal pathogens have been identified to be responsible for this disease in Australia, namely Peyronellaea pinodes, Peyronellaea pinodella and Phoma koolunga. Limited genomic resources for these pathogens have been generated, which has hampered the implementation of effective management strategies and breeding for resistant cultivars. Using Oxford Nanopore long-read sequencing, we report the first high-quality, fully annotated, near-chromosome-level nuclear and mitochondrial genome assemblies for 18 isolates from the Australian AB complex. Comparative genome analysis was performed to elucidate the differences and similarities between species and isolates using phylogenetic relationships and functional diversity. Our data indicated that P. pinodella and P. koolunga are heterothallic, while P. pinodes is homothallic. More homology and orthologous gene clusters are shared between P. pinodes and P. pinodella compared to P. koolunga. The analysis of the repetitive DNA content showed differences in the transposable repeat composition in the genomes and their expression in the transcriptomes. Significant repeat expansion in P. koolunga's genome was seen, with strong repeat-induced point mutation (RIP) activity being evident. Phylogenetic analysis revealed that genetic diversity can be exploited for species marker development. This study provided the much-needed genetic resources and characterization of the AB species to further drive research in key areas such as disease epidemiology and host-pathogen interactions.

Encrusted Uropathy: A Comprehensive Overview-To the Bottom of the Crust

Encrusted uropathy is a rare subacute to chronic inflammatory disorder caused by infection with urease-producing bacteria, mainly Corynebacterium urealyticum. The disorder is characterized by urothelial deposition of struvite and carbonated apatite, resulting in encrustations and ulceronecrotic inflammation of the urothelium and surrounding tissues. Most commonly, encrusted uropathy is encountered in patients with predisposing conditions. The disease remains underdiagnosed. High urinary pH and negative conventional urine cultures should raise suspicion of the diagnosis. Prognosis is dependent on timely diagnosis and treatment installment, which consists of urological removal of encrustations in combination with urinary acidification and long-term antibiotic therapy.

Genome sequence of a multidrug-resistant Corynebacterium striatum isolated from bloodstream infection from a nosocomial outbreak in Rio de Janeiro, Brazil

Multidrug-resistant (MDR) Corynebacterium striatum has been cited with increased frequency as pathogen of nosocomial infections. In this study, we report the draft genome of a C. striatum isolated from a patient with bloodstream infection in a hospital of Rio de Janeiro, Brazil. The isolate presented susceptibility only to tetracycline, vancomycin and linezolid. The detection of various antibiotic resistance genes is fully consistent with previously observed multidrug-resistant pattern in Corynebacterium spp. A large part of the pTP10 plasmid of MDR C. striatum M82B is present in the genome of our isolate. A SpaDEF cluster and seven arrays of CRISPR-Cas were found.

Advanced In Silico Tools for Designing of Antigenic Epitope as Potential Vaccine Candidates Against Coronavirus

Vaccines are the most economical and potent substitute of available medicines to cure various bacterial and viral diseases. Earlier, killed or attenuated pathogens were employed for vaccine development. But in present era, the peptide vaccines are in much trend and are favoured over whole vaccines because of their superiority over conventional vaccines. These vaccines are either based on single proteins or on synthetic peptides including several B-cell and T-cell epitopes. However, the overall mechanism of action remains the same and works by prompting the immune system to activate the specific B-cell- and T-cell-mediated responses against the pathogen. Rino Rappuoli and others have contributed in this field by plotting the design of the most potent and fully computational approach for discovery of potential vaccine candidates which is popular as reverse vaccinology. This is quite an unambiguous advance for vaccine evolution where one begins with the genome information of the pathogen and ends up with the list of certain epitopes after application of multiple bioinformatics tools. This book chapter is an effort to bring this approach of reverse vaccinology into notice of readers using example of coronavirus.

Corinebacterium urealyticum: increased incidence of infection and encrusted uropathy

INTRODUCTION

Corynebacterium urealyticum (CU) affects patients who are immunosuppressed, chronically ill or have undergone numerous operations. Obstructive uropathy (OU) is a complication of infection.

STUDY OBJECTIVE

To demonstrate the growing increase in cases of infection by CU and OU in the past 5 years.

MATERIAL AND METHODS

A descriptive study was conducted of urological patients with CU-positive urine cultures (January 2009-December 2014). We calculated the annual distribution and clinical characteristics of infection by CU and OU. Minimum follow-up: 6 months. We obtained the statistical means and ranges of clinical parameters pre/post-therapy.

RESULTS

The total number of patients with CU was 115 (men, 87; women, 28). The mean age was 67.9 years (range, 6-95 years), and the annual distribution of cases for 2009, 2010, 2011, 2012, 2013 and 2014 was 9 (7.8%), 13 (11.3%), 9 (7.8%), 20 (17.4%), 31 (27%) and 33 (28.7%), respectively. The increase in cases for 2009-2014 was 300%. Multiple urological surgeries were performed in 89 cases (77.3%), with surgical complications in 77 cases (66.9%). Eighteen (15.6%) patients had OU (men, 13; women, 5), 12 had pyelitis (66.7%), 3 had cystopathy (16.6%), 2 had prostatic capsule disease (11.2%) and 1 had mesh calcification (5.5%). The analysis of the 18 cases with OU showed pre/postantibiotic therapy urine pHs of 8 (r, 6-9) vs. 6 (r, 5-7). All postantibiotic cultures were negative. Acidifying solution was applied in 5 cases, and surgery was performed in 13 cases (72.2%). The results from before/after the multimodal therapy showed renal impairment in 12 (66.6%) vs. 9 cases (50%) and glomerular filtration rates (GFR) of 45.8 (r, 6->90) vs. 52.7 (r, 13->90). The improvement in GFR was 6.94 points (T Wilcoxon; P=.102). The radiology results (incrustations) showed improvement in 13 patients (72.2%) and no change in 5 (27.8%). There was no specific mortality for CU.

CONCLUSIONS

The prevalence of infection by CU and OU is increasing. Antibiotic treatment is highly effective. Acidifying solutions are an acceptable option for reducing calcifications.