Shigella flexneri serotype 1b is among the most prominent serotypes in developing countries, followed by serotype 2a. However, only limited data is available on the global phenotypic and genotypic characteristics of S. flexneri 1b. In the present study, 40 S. flexneri 1b isolates from different regions of China were confirmed by serotyping and biochemical characterization. Antimicrobial suscept...

Shigella flexneri serotypes 1b and 1a are Gram-negative enteroinvasive bacteria causing shigellosis in humans. The O-antigen from S. flexneri 1b is a { → 2)-[3Ac/4Ac]-α-L-RHAP-(1 → 2)-α-L-Rhap-(1 → 3)-[2Ac]-α-L-Rhap-(1 → 3)-[α-D-Glcp-(1 → 4)]-β-D-GlcpNAc-(1 → }n branched polysaccharide ({(Ac)AB(Ac)C(E)D}n). It is identical to that from S. flexneri 1a, except for the 2C-acetate. A concise synthe...

Outer membrane protein A (OmpA) is a multifaceted predominant outer membrane protein of Escherichia coli and other Enterobacteriaceae whose role in the pathogenesis of various bacterial infections has recently been recognized. Here, the role of OmpA on the virulence of Shigella flexneri has been investigated. An ompA mutant of wild-type S. flexneri 5a strain M90T was constructed (strain HND92) ...

Neuronal Wiskott-Aldrich syndrome protein (N-WASP) and the actin-related protein 2/3 (Arp2/3) complex have emerged as critical host proteins that regulate pathogen actin-based motility. Actin tail formation and motility in Listeria monocytogenes require the Arp2/3 complex but bypasses N-WASP signaling. Motility of Shigella flexneri and vaccinia virus requires both N-WASP and the Arp2/3 complex....

The two-component signal transduction system PhoP/PhoQ is an important regulator for stress responses and virulence in most Gram-negative bacteria, but characterization of PhoP/PhoQ in Shigella has not been thoroughly investigated. In the present study, we found that deletion of phoPQ (ΔphoPQ) from Shigella flexneri 2a 301 (Sf301) resulted in a significant decline (reduced by more than 15-fold)...

BACKGROUND The emergence of fosfomycin resistance and extended-spectrum β-lactamase (ESBL) genes is a serious threat to public health and a new challenge in shigellosis treatment. The purpose of this study was to identify fosfomycin resistance and characterize β-lactamase genes in fos-carrying isolates of Shigella flexneri from patients in China. METHODS A total of 263 S. flexneri isolates we...

Twenty-one atypical Shigella flexneri type 4 strains isolated from patients attending the Dhaka treatment center of the International Centre for Diarrhoeal Disease Research, Bangladesh, were extensively characterized and compared with S. flexneri serotypes 4a and 4b. The atypical strains agglutinated only with the type antigen factor 4 and did not agglutinate with any group factors, thereby exc...

A means for determining immune status against shigellosis would significantly improve the design and evaluation of interventional and other epidemiologic studies. Previous case-control studies have indicated the potential role of humoral antilipopolysaccharide antibodies. To test this proposition, 190 soldiers serving in a field unit were monitored prospectively for 2.5 months for shigellosis. ...

Culture filtrates of Shigellaflexneri 2a strain M4243 grown in iron-depleted medium, caused significant fluid accumulation in rabbit ileal loops. Also, when tested in Ussing chambers, a greater rise in potential difference and short circuit current was seen with such filtrates compared with the medium control. Analogous filtrates from two M4243 derivatives lacking the 140-MD invasiveness plasmi...

In this study, we measured the drug resistance conferred by mdfA mutations in two Shigella flexneri strains. A mutant in mdfA genes was constructed by polymerase chain reaction-based, one-step inactivation of chromosomal genes. The antimicrobial susceptibility of parent and mutant strains to fluoroquinolones was determined by minimal inhibitory concentration (MICs). The △mdfA mutants were somew...