Dominant serotype distribution and antimicrobial resistance profile of Shigella spp. in Xinjiang, China

Abstract

Shigella represents one of the major diarrhea-inducing pathogens threatening public health, but its prevalence and antimicrobial resistance profile in Xinjiang Uygur Autonomous region, China, remains unclear. We conducted comprehensive investigation of Shigella serotype distribution and antimicrobial resistance pattern in Xinjiang, identifying 458 Shigella isolates between 2008 to 2014. Shigella flexneri was identified as predominant species, and several S. flexneri serotypes were isolated, including atypical serotypes 1c, 2c, and 4s. Dominant S. flexneri serotypes were 2a, 1b, 2b, and Xv, different from those generally dominant in China. A hybrid serotype pattern was observed, which included the major Chinese serotypes (2a, Xv) and those predominant in Pakistan (1b, 2b). Shigella sonnei was shown to have a lower frequency compared with that generally observed in China, but an increasing trend of infections associated with this pathogen was observed. Furthermore, a high frequency of drug resistance and different Shigella antimicrobial resistance patterns were demonstrated as well, including very severe resistance phenotypes, such as multidrug resistance and resistance to frontline antibiotics. Seventy-five cephalosporin-resistant Shigella isolates were frequently identified with the resistance determinants that can undergo horizontal transfer, such as blaOXA, blaTEM, blaCTX-M, and integrons, facilitating the development of cephalosporin resistance among Shigella subtypes. Additionally, genetic analyses demonstrated that all 86 quinolone-resistant S. flexneri isolates possess 3–4 mutation sites in quinolone resistance-determining regions, primarily contributing to their resistance to quinolone. However, S. sonnei isolates were not shown to be quinolone resistant. Co-resistance to cephalosporins and quinolones was detected in 17 S. flexneri isolates, and these isolates were additionally multidrug resistant and carried β-lactamase genes and quinolone-resistance determinants. As is demonstrated in this study, dominant serotypes of Shigella were distributed in unique trend with dangerous drug resistance patterns. Novel strategies are urgently required to prevent the development of drug resistance among diarrhea-inducing pathogens.

Extensive inter-strain diversity among clinical isolates of Shigella flexneri with reference to its serotype, virulence traits and plasmid incompatibility types, a study from south India over a 6-year period

“…Further, serotype 6 was the most dominant. Heterogeneity in distribution of other serotypes was noticed among isolates in this study as has been elaborated in Additional file 2: Table S3 [5,10, 26–29]. The mixture of other serotypes identified in this study is disparate, thus showing that there is no homogenous distribution of serotypes globally as shown in Table 2.…”

Burden, Antibiotic Resistance, and Clonality of Shigella spp. Implicated in Community-Acquired Acute Diarrhoea in Lilongwe, Malawi

“…Similar trends have earlier been noted in Iran [ 36 ] and Ethiopia [ 37 ], where they reported 49.8% and 14.0%, respectively, of Shigella flexneri isolates. However, in a study conducted in Xinjiang, Uygur in China, although Shigella flexneri was the most prevalent species (79%), other species like Shigella sonnei were also reported [ 38 ]. The differences in species recorded in different studies is attributed to the geographical stratification of Shigella species due to countriess’ economic statuses.…”

Association of Serotype With Antimicrobial Resistance Patterns Among Shigella flexneri Isolates From Pakistan: The Importance of Serotype 2b

“…Molecular characterization of S. flexneri isolates is important to understand the disease burden caused by new Shigella serotypes, vaccine development and to prevent the emergence of MDR bacteria. [7][8][9][10][11][12][13]20,21 Several studies reported evidence about association of S. flexneri serotype with antibiotic resistance pattern. [4][5][6][7][8][9][10][11][12][13][14] The current study is highlighting the molecular serotyping of S. flexneri and their association with antimicrobial resistance patterns in Pakistan.…”