Clostridium culturomicium sp. nov. and Clostridium jeddahitimonense sp. nov., novel members of the Clostridium genus isolated from the stool of an obese Saudi Arabian.

Taxono-genomics is an innovative concept coined for the description of new bacterial species. Phenotypic characteristics were combined with a genomic approach to describe two new species within the Clostridium senso stricto genus: Clostridium culturomicium strain CL-6T and Clostridium jeddahitimonense strain CL-2T, both isolated from the gut microbiota of an obese man from Saudi Arabia. Strains CL-6T and CL-2T shared a similarity of 98.4% with the 16S rRNA gene of Clostridium subterminale strain JCM 1417T (accession number NR113027) and 98% with that of Clostridium disporicum strain DS1T (accession number NR026491), respectively. The highest OrthoANI values were shared with Clostridium punense for strain CL-6T (70.8%) and with Clostridium disporicum for strain CL-2T (87.1%). Additionally, strain CL-6T and strain CL-2T shared a 16S rRNA similarity of 91.4%. Both strains were anaerobic, spore-forming and Gram-stain-positive non-motile bacilli. The genome of Clostridium culturomicium strain CL-6T is 4,325,182 bp long with 32.2% GC content. As for Clostridium jeddahitimonense strain CL-2T, the genome is 4,074,758 bp long with 29.2% GC content.

In vitro antibacterial activity of honey against multidrug-resistant Shigella sonnei.

BACKGROUND AND PURPOSE: The health benefits of honey as an oral therapeutic agent for the treatment of diarrhoea caused by Shigella sonnei depend on the ability of honey to withstand human gastrointestinal conditions. This study aimed to investigate whether honey could withstand and inhibit the growth of Shigella sonnei under such conditions. MATERIALS AND METHODS: We initially evaluated the survival of Shigella sonnei in human simulated gastric conditions (SGC) and simulated intestinal conditions (SIC). This was followed by determination of the susceptibility of Shigella sonnei to Manuka and Talah honey under gastrointestinal conditions. The colony forming units (CFU) of Shigella sonnei and minimum inhibitory concentrations (MICs) of honey were calculated. RESULTS: Shigella sonnei was unable to survive in the acidic environment of the stomach without food matrix and survived only when inoculated with a food source, resulting in 1.5 × 105 ± 0.2 CFU at 60 min and 1.7 × 105 ± 0.3 CFU after 120 min of incubation. In SIC, it survived both with and without food matrix at the same CFU (1.2 × 107 ±0.4) at 60 min and 1.7 × 107 ±0.2 CFU after 120 min of incubation. Growth of Shigella sonnei was not observed in SGC in the presence of either honey at different concentrations without a food source. In the presence of a food source, Manuka honey inhibited the growth of Shigella sonnei at 10% v/v and Talah honey at 20% v/v dilutions in SGC. In SIC, Manuka honey inhibited the growth of Shigella sonnei at 15% and 20% v/v dilutions, whereas Talah honey inhibited Shigella sonnei at 20% and 25% v/v dilutions without and with food sources, respectively. CONCLUSION: Shigella sonnei can survive in the acidic environment of the stomach if inoculated with a food source. Acidic pH and pepsin had no deleterious effects on the antibacterial capability of honey. However, bile reduced the antibacterial activity of honey in the intestinal environment.

Cross-sectional prevalence study of MERS-CoV in local and imported dromedary camels in Saudi Arabia, 2016-2018.

The Middle East Respiratory Syndrome-Coronavirus (MERS-CoV) is an endemic virus in dromedaries. Annually, Saudi Arabia imports thousands of camels from the Horn of Africa, yet the epidemiology of MERS-CoV in these animals is largely unknown. Here, MERS-CoV prevalence was compared in imported African camels and their local counterparts. A total of 1399 paired sera and nasal swabs were collected from camels between 2016 and 2018. Imported animals from Sudan (n = 829) and Djibouti (n = 328) were sampled on incoming ships at Jeddah Islamic seaport before unloading, and local camels were sampled from Jeddah (n = 242). Samples were screened for neutralizing antibodies (nAbs) and MERS-CoV viral RNA. The overall seroprevalence was 92.7% and RNA detection rate was 17.2%. Imported camels had higher seroprevalence compared to resident herds (93.8% vs 87.6%, p <0.01) in contrast to RNA detection (13.3% vs 35.5%, p <0.0001). Seroprevalence significantly increased with age (p<0.0001) and viral RNA detection rate was ~2-folds higher in camels <2-year-old compared to older animals. RNA detection was higher in males verses females (24.3% vs 12.6%, p<0.0001) but seroprevalence was similar. Concurrent positivity for viral RNA and nAbs was found in >87% of the RNA positive animals, increased with age and was sex-dependent. Importantly, reduced viral RNA load was positively correlated with nAb titers. Our data confirm the widespread of MERS-CoV in imported and domestic camels in Saudi Arabia and highlight the need for continuous active surveillance and better prevention measures. Further studies are also warranted to understand camels correlates of protection for proper vaccine development.

Enzootic patterns of Middle East respiratory syndrome coronavirus in imported African and local Arabian dromedary camels: a prospective genomic study.

BACKGROUND: The Middle East respiratory syndrome coronavirus (MERS-CoV) is a lethal zoonotic pathogen endemic to the Arabian Peninsula. Dromedary camels are a likely source of infection and the virus probably originated in Africa. We studied the genetic diversity, geographical structure, infection prevalence, and age-associated prevalence among camels at the largest entry port of camels from Africa into the Arabian Peninsula. METHODS: In this prospective genomic study, we took nasal samples from camels imported from Sudan and Djibouti into the Port of Jeddah in Jeddah, Saudi Arabia, over an almost 2-year period and local Arabian camels over 2 months in the year after surveillance of the port. We determined the prevalence of MERS-CoV infection, age-associated patterns of infection, and undertook phylogeographical and migration analyses to determine intercountry virus transmission after local lineage establishment. We compared all virological characteristics between the local and imported cohorts. We compared major gene deletions between African and Arabian strains of the virus. Reproductive numbers were inferred with Bayesian birth death skyline analyses. FINDINGS: Between Aug 10, 2016, and May 3, 2018, we collected samples from 1196 imported camels, of which 868 originated from Sudan and 328 from Djibouti, and between May 1, and June 25, 2018, we collected samples from 472 local camels, of which 189 were from Riyadh and 283 were from Jeddah, Saudi Arabia. Virus prevalence was higher in local camels than in imported camels (224 [47·5%] of 472 vs 157 [13·1%] of 1196; p<0·0001). Infection prevalence peaked among camels older than 1 year and aged up to 2 years in both groups, with 255 (66·9%) of 381 positive cases in this age group. Although the overall geographical distribution of the virus corresponded with the phylogenetic tree topology, some virus exchange was observed between countries corresponding with trade routes in the region. East and west African strains of the virus appear to be geographically separated, with an origin of west African strains in east Africa. African strains of the virus were not re-sampled in Saudi Arabia despite sampling approximately 1 year after importation from Africa. All local Arabian samples contained strains of the virus that belong to a novel recombinant clade (NRC) first detected in 2014 in Saudi Arabia. Reproduction number estimates informed by the sequences suggest sustained endemicity of NRC, with a mean Re of 1·16. INTERPRETATION: Despite frequent imports of MERS-CoV with camels from Africa, African lineages of MERS-CoV do not establish themselves in Saudi Arabia. Arabian strains of the virus should be tested for changes in virulence and transmissibility. FUNDING: German Ministry of Research and Education, EU Horizon 2020, and Emerging Diseases Clinical Trials Partnership.

Adjuvants for Clostridium tetani and Clostridium diphtheriae vaccines updating.

It's known that diphtheria and tetanus are a contagious lethal diseases over the years, they caused by pathogenic microbes corynebacterium diphtheria and Clostridium tetani, respectively. The diseases result from the production of bacterial toxin. Vaccination with bacterial toxoid vaccines adsorbed on particulates adjuvants still are the best way to prevent this epidemic diseases from spread. The particulate vaccines have been shown to be more efficient than soluble one for the induction of the immune responses. Nanoparticles can be engineered to enhance the immune responses. As well known the immune response to inactivate killed and subunit vaccine enhances by alum adjuvants. The adjuvants examined and tested after reducing its size to particle size, thus mimic size of viruses which is considered smallest units can derive the immune system. The major issue is minimizing the adjuvant particles, to gain insight of resulting immunity types and impact on immune response. The adjuvant effect of micro/nanoparticles appears to largely be a consequence of their uptake into antigen presenting cells.