Academy of Military Medical Sciences, Academy of Military Sciences, Beijing, China.
Institute of Disease Control and Prevention, PLA, Beijing, China.
PLoS One. 2018 Apr 3;13(4):e0195259. doi: 10.1371/journal.pone.0195259. eCollection 2018.
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.
志贺氏菌是威胁公共健康的主要腹泻致病菌之一，但在中国新疆维吾尔自治区，其流行情况和抗菌药物耐药性谱尚不清楚。我们对新疆的志贺氏菌血清型分布和抗菌药物耐药模式进行了全面调查，在 2008 年至 2014 年间共分离出 458 株志贺氏菌。鉴定出福氏志贺菌为主要流行菌，分离出几种福氏志贺菌血清型，包括非典型血清型 1c、2c 和 4s。优势福氏志贺菌血清型为 2a、1b、2b 和 Xv，与中国常见的优势血清型不同。观察到混合血清型模式，包括中国主要血清型（2a、Xv）和巴基斯坦主要流行血清型（1b、2b）。志贺氏菌宋内氏的感染频率低于中国一般观察结果，但观察到与该病原体相关的感染呈上升趋势。此外，还表现出较高的药物耐药率和不同的志贺氏菌抗菌药物耐药模式，包括严重的多药耐药和对一线抗生素的耐药。频繁分离出 75 株头孢菌素耐药志贺氏菌，这些菌株携带可发生水平转移的耐药决定因子，如 blaOXA、blaTEM、blaCTX-M 和整合子，促进了头孢菌素类药物在志贺菌亚型中的耐药性发展。此外，遗传分析表明，所有 86 株福氏志贺菌耐喹诺酮株均在喹诺酮耐药决定区存在 3-4 个突变位点，主要导致其对喹诺酮类药物的耐药性。然而，宋内氏志贺菌分离株并未表现出对喹诺酮类药物的耐药性。在 17 株福氏志贺菌中检测到对头孢菌素和喹诺酮类药物的共同耐药性，这些分离株还具有多药耐药性，并携带β-内酰胺酶基因和喹诺酮耐药决定因子。本研究表明，志贺氏菌的优势血清型分布呈独特趋势，具有危险的耐药模式。迫切需要新的策略来防止腹泻致病菌耐药性的发展。
