Virulence gene profiles of Shigella species isolated from stool specimens in India: its association with clinical manifestation and antimicrobial resistance

Abstract

Shigella is the major cause of bacillary dysentery worldwide, especially in developing countries. There are several virulence factors essential for the organism to be virulent which are generally present in the virulence plasmid and on chromosomal pathogenicity islands. The present study was undertaken to determine the virulence gene profile of Shigella spp isolated from a clinical specimen and to study their significant association with common clinical symptoms and antimicrobial resistance. Sixty Shigella whole genome sequences, including 22 S. flexneri, 14 S. sonnei, 17 S. boydii and 7 S. dysenteriae were analyzed for the presence of virulence genes. The gene found predominantly in this study were ipaH (90%) followed by sigA (83%), and lpfA (78%) respectively. The virulence genes were significantly higher in S. flexneri, particularly in serotype 2 compared to S. sonnei. Interestingly, a significant association was observed between sigA gene and fever whereas sepA and sigA were found to be associated with diarrhea. Among the studied Shigella isolates, the presence of virulence genes was found higher in isolates resistant to more than three antibiotic classes. The present work revealed the varying incidence of virulence determinants among different Shigella serogroups and shows their contribution to disease severity.

Acquisition and loss of CTX-M plasmids in Shigella species associated with MSM transmission in the UK

“…The S. flexneri isolate harboured secretion autotransporter toxin sat and sepA which is associated with intense abdominal pain [ 64 ]. However, S. sonnei isolates exhibited higher numbers of virulence genes, including senB and sigA associated with bloody diarrhoea and fever respectively [ 65 ]. Presence of isolates with high levels of both AMR and virulence factors could be a consequence of clinically severe cases requiring antibiotics and exerting selective pressure and are a public health concern due to the challenge this poses to outbreak management.…”

Clinical and Genomic Investigation of an International Ceftriaxone- and Azithromycin-Resistant Shigella sonnei Cluster among Men Who Have Sex with Men, Montréal, Canada 2017–2019

“…Virulence gene presence and frequencies for our S. sonnei cluster were considered normal, since many hallmarks of S. sonnei were detected, such as celb , gad , lpfA , senB , and sigA ( 29 , 30 ). The low detection frequency of some of the virulence genes ( capU and ipaD ) can be attributed to their location on the large virulence plasmid, which can be highly unstable in storage or in laboratory media and is therefore commonly lost upon subculturing ( 31 ).…”

Effect of Psidium guajava (guava) L. Leaf Decoction on Antibiotic-resistant Clinical Diarrhoeagenic Isolates of Shigella spp.

“…46,47 The presence of several virulence factors and toxins are associated with the pathogenicity of Shigella spp. 48,49 Bloody diarrhoea, which is a critical condition observed in shigellosis, is induced by the sen gene and has been reported across all species of Shigella. [49][50][51] It has been reported that dehydration in shigellosis leading to watery diarrhoea is potentially caused by the set1B gene predominantly found only in S. flexneri.…”

“…48,49 Bloody diarrhoea, which is a critical condition observed in shigellosis, is induced by the sen gene and has been reported across all species of Shigella. [49][50][51] It has been reported that dehydration in shigellosis leading to watery diarrhoea is potentially caused by the set1B gene predominantly found only in S. flexneri. 52,53 Recent studies have shown that S. flexneri possesses more virulent factors compared to other Shigella spp.…”