Jundishapur Journal of Microbiology
Volume:15 Issue: 4, Apr 2022

Colorectal cancer (CRC) is the third most common malignant tumor worldwide. Emerging evidence suggests that dysbiosis of the colon microbiome may be involved in CRC development.

The present study aimed to compare the composition and diversity of the colon microbiome by high-throughput 16S ribosomal RNA (rRNA) sequencing between CRC patients and healthy controls. Microbiome composition and diversity were also examined based on gender.

The colon microbiome richness and diversity of samples from 17 CRC patients and 13 healthy controls were analyzed by 16S rRNA sequencing. Alpha and beta diversity were calculated to determine the differences in colon microbiome diversity.

Alpha and beta diversity showed significant differences between the CRC and healthy control groups regarding the microbiome. Our results showed that CRC samples had the highest richness and diversity. The total number (P ≤ 0.01), phylogenetic diversity (P ≤ 0.01), Chao1 (P ≤ 0.01), Shannon (P ≤ 0.05), and Simpson (P ≤ 0.01) indices were significantly higher in the CRC group than in the healthy control group. In addition, the comparison between females and males showed that the microbiome diversity was higher in the CRC female (CRC-F) group than in other groups. Prevotella, Fusobacterium, Akkermansia, Leptotrichia, Streptococcus, and Parabacteroides were more commonly observed in the CRC group, while Bacteroides, Enterobacteriaceae (unknown genus), Ruminococcus, and Campylobacter were more commonly observed in the healthy control group.

This study showed differences between the CRC and healthy control groups regarding the diversity and composition of the colon microbiome, suggesting a contribution of the microbiome in the development and progression of CRC.

Studies have shown that oral bacteria are involved in the occurrence of some neurological diseases. Autism spectrum disorder (ASD), a neurodevelopmental disorder occurring in early life, is closely related to intestinal bacteria. At present, the role of the oral microbiota in ASD rarely remains unexplored.

This study aimed to explore the differences of bacteria in saliva between autistic and healthy children in early childhood and investigate whether there are any specific salivary bacteria serving as biomarkers of ASD.

A total of 10 autistic children aged 2 - 6 years and 10 healthy children matched in age, gender, and region in China were involved in this study. 16S ribosomal ribonucleic acid sequencing was employed to detect the disparities of bacteria in saliva between autistic children and healthy children. Moreover, the relationship between salivary differential bacteria and intestinal bacteria in autistic children was analyzed to screen out salivary differential bacteria that were unrelated to intestinal bacteria.

There were 14 bacteria in the saliva of children with autism, which were different from those of the control group (P < 0.05). Correlation analysis showed that the salivary Bacteroides fragilis had no apparent relationship with intestinal bacteria (P > 0.05); nevertheless, the rest of the differential bacteria in saliva were significantly related to intestinal bacteria.

There were differential bacteria in the saliva of children with ASD and healthy controls, indicating that salivary bacteria might play a role in ASD. Nevertheless, further studies are needed to identify the pathogenesis of ASD.

Extraintestinal pathogenic Escherichia coli (ExPEC) can colonize the urinary system with various virulence factors. Escaping from the host defense, can lead to serious infections, such as bacteremia and sepsis.

This study aimed to investigate the presence of phylogenetic groups, various virulence factor genes, and pathogenicity island (PAI) markers of extraintestinal and commensal E. coli isolates.

Within January 2016 and December 2017, 50 E. coli isolates were isolated from simultaneous blood and urine samples of 25 patients hospitalized in Mersin University Faculty of Medicine, Turkey, and 50 commensal E. coli isolates were isolated from fecal 18 samples of healthy volunteers as the control group was included in the study. Phylogenetic groups, virulence factors genes, and PAI markers were determined by the multiplex polymerase chain reaction method.

The majority of ExPEC isolates were observed to be in phylogenetic group B2. All of the commensal E. coli isolates were detected in phylogenetic group A. The most predominant virulence factor gene was traT (80%). The most prevalent PAI marker was PAI IV536 (86%). However, the PAI I536, IJ96, and IIJ96 markers were not detected in any isolates. Only PAI IV536 was detected in commensal E. coli isolates.

It was determined that E. coli isolates that cause uropathogenic and bloodstream infections contain a higher frequency of PAI than commensal isolates.

Pancreatic cancer is a lethal tumor with a poor prognosis. The connection between pancreatic cancer and gut microbiota is less reported.

This study analyzed microbial characteristics in patients with pancreatic cancer from the tropical area of China and explored the potential impact of the characteristic microflora on pancreatic cancer.

Stool samples and blood test indices of participants were collected in Hainan, China. Metagenomic sequencing was used to analyze the gut microbiota characteristics. The R corrplot package was used to analyze the correlation between gut microbiota and blood test indices.

The microbial community in pancreatic cancer were clustered together and significantly separated from controls. The Simpson index was increased significantly in pancreatic cancer compared to controls. The abundances of butyrate-producing bacteria (Anaerostipes hadrus, Lachnoclostridium phocaeense, and Romboutsia ilealis), Bifidobacteria, and [Eubacterium] eligens were significantly decreased, while Fusobacterium, Enterobacter, and Enterococcus were significantly increased in pancreatic cancer. Prevotella copri may have a vital role in the bacterial interaction network. Pathways connected to metabolism, environment (bacterial secretion system), genetic information (protein export and ribosome), and human diseases (infectious diseases and drug resistance) were increased in the pancreatic cancer group. Butyrate-producing bacteria (butyrate-producing bacterium SS3/4, A. hadrus, R. intestinalis, and Faecalibacterium prausnitzii) and Bifidobacteria were significantly negatively correlated with the neutrophil-to-lymphocyte ratio.

The gut microbiome was distinct in patients with pancreatic cancer from the tropical area of China. Changes in intestinal flora abundance and metabolic pathways may play an essential role in the occurrence and development of pancreatic cancer.

In Corynebacterium diphtheriae, the dtxR gene plays a role in regulating diphtheria toxin synthesis. The dtxR gene is often used as a marker for identifying C. diphtheriae by the polymerase chain reaction (PCR) method because it is present in all strains of this bacterium. Mutations in the dtxR gene can cause the over-synthesis of diphtheria toxin and reduce PCR assays' sensitivity.

This study aimed to describe the polymorphisms in the dtxR gene of C. diphtheriae isolated from a diphtheria outbreak in Indonesia.

Forty-eight isolates of C. diphtheriae were obtained from clinical samples (throat/nasopharyngeal swabs) of diphtheria cases and close contacts. The isolates were revived on a blood agar plate (BAP), bacterial colonies were harvested, and deoxyribonucleic acid (DNA) was extracted. The DNA sequencing was carried out using a Whole-genome Sequencing (WGS) approach. The data were converted and analyzed with U-gene software. The dtxR gene analysis was performed with C. diphtheriae PW8 as references.

There were 59-point mutation locations in 48 isolates examined. None of these single nucleotide polymorphisms (SNPs) coded for amino acid changes. Based on the mutation pattern, seven clades/groups of the dtxR gene of 48 C. diphtheriae isolates were examined.

At least seven types of DNA sequences and more than 50 SNPs of the dtxR gene were identified in 48 C. diphtheriae isolates from a diphtheria outbreak in Indonesia. Although all of them are silent mutations, they must be considered in the design of PCR examination in diphtheria laboratories.

Clinically, rat bite fever (RBF) is a condition caused by Spirillum minus or Streptobacillus moniliformis infections, following rat or any rodent bite. In the absence of a rat bite, this condition cannot be accurately diagnosed. Here, we report the first case of RBF due to S. moniliformis but without a rat bite in China.

A 77-year-old woman with reactive arthritis was admitted to the hospital due to high fever. Initially, we suspected reactive arthritis with liver function deterioration. However, we isolated a bacterium which was confirmed to be S. moniliformis using Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). Subsequently, the patient was given targeted anti-infective treatment, which completely resolved the symptoms. The patient was discharged upon fully recovery.

Rat bite fever infection caused by S. moniliformis may occur without actual rodent bite. MALDI-TOF MS may be applied to determine the diagnosis of RBF. Difficulties in pathogen and clinical diagnosis highlight the need for discovering the complete exposure history and a greater understanding of this rare zoonotic infections.