The Marshall Centre for Infectious Diseases Research and Training, School of Biomedical Sciences, The University of Western Australia, Crawley, Australia.
Ministry of Education, Riyadh, Saudi Arabia.
Microb Genom. 2023 Mar;9(3). doi: 10.1099/mgen.0.000969.
In Australia, gonococcal isolates are monitored for antimicrobial susceptibilities. In Western Australia (WA), gonorrhoea notification rates increased by 63 % between 2013 and 2016, with the steepest increase occurring between 2015 and 2016, before stabilizing at this higher baseline between 2017 and 2020. This increased prevalence was associated with antimicrobial-susceptible (AMS) lineages. To understand the provenance of these isolates causing gonorrhoea in WA, whether they were introduced or expanded from endogenous lineages, 741 isolates were collected in 2017 and characterized by both iPLEX typing and whole genome sequencing (WGS). Antibiograms and genocoding of the isolates revealed that AMS isolates were most prevalent in the remote regions, while the urban/rural regions were characterized by antimicrobial-resistant (AMR) isolates. iPLEX typing identified 78 iPLEX genotypes (WA-1 to WA-78) of which 20 accounted for over 88 % of isolates. WA-10 was the most frequently identified genotype in the urban/rural regions whilst WA-29 was the most frequently identified genotype in the remote regions. Genotypes WA-38, WA-52 and WA-13 accounted for 81 % (=36/44) of the azithromycin-resistant (AziR) isolates. A representative isolate of each iPLEX genotype and AMR biotype was whole genome sequenced and analysed using MLST, NG-MAST and NG-STAR, and the novel core genome clustering Ng_cgc_400 typing scheme. Five predominant Bayesian population groups (termed BPG-1 to 5) were identified in the study collection. BPG-1 and BPG-2 were associated with AMS isolates from the remote regions. BPG-1 and BPG-2 were shown to be unique to the remote regions based on a minimum spanning tree against 4000 international isolates. AMS isolates in urban/rural regions were dominated by international lineages. AziR and Cef DS (decreased susceptibility to ceftriaxone) was concentrated in three urban/rural genomic groups (BPG-3, 4 and 5). Azithromycin minimum inhibitory concentrations (0.5-16 mg l) correlated with the accumulation of mutations or/and the fraction of 23S rRNA C2611T mutated copies. The majority of isolates in BPG-3, 4 and 5 could be correlated with known AMR lineages circulating globally and nationally. In conclusion, the surge in AMS isolates in WA in 2017 was due to importation of international AMS lineages into urban/rural regions, whilst the local AMS lineages persisted largely in the remote regions. Bridging between the urban/rural and remote regions was relatively rare, but continued surveillance is required to prevent ingress of AMR strains/lineages into the remote regions of WA.
在澳大利亚，对淋球菌分离株进行了抗微生物药物敏感性监测。在西澳大利亚州（WA），2013 年至 2016 年期间淋病报告发病率增长了 63%，2015 年至 2016 年期间增幅最大，之后在 2017 年至 2020 年期间稳定在这一较高基线水平。这种流行率的增加与抗微生物药物敏感性（AMS）谱系有关。为了了解这些导致 WA 淋病的分离株的起源，无论是从内源性谱系引入还是扩大，2017 年收集了 741 株分离株，并通过 iPLEX 分型和全基因组测序（WGS）进行了特征描述。抗生素谱和分离株的基因编码显示，AMS 分离株在偏远地区最为常见，而城市/农村地区则以抗微生物药物耐药（AMR）分离株为特征。iPLEX 分型确定了 78 种 iPLEX 基因型（WA-1 至 WA-78），其中 20 种占分离株的 88%以上。WA-10 是城市/农村地区最常见的基因型，而 WA-29 是偏远地区最常见的基因型。WA-38、WA-52 和 WA-13 基因型占 81%（=36/44）的阿奇霉素耐药（AziR）分离株。每种 iPLEX 基因型和 AMR 生物型的代表性分离株均进行了全基因组测序，并使用 MLST、NG-MAST 和 NG-STAR 以及新型核心基因组聚类 Ng_cgc_400 分型方案进行了分析。在研究中收集的五个主要贝叶斯种群组（称为 BPG-1 至 5）被确定。BPG-1 和 BPG-2 与偏远地区的 AMS 分离株有关。基于对 4000 株国际分离株的最小生成树，BPG-1 和 BPG-2 被证明是偏远地区特有的。城市/农村地区的 AMS 分离株主要来自国际谱系。AziR 和头孢 DS（头孢曲松敏感性降低）集中在三个城市/农村基因组组（BPG-3、4 和 5）中。阿奇霉素最小抑菌浓度（0.5-16mg/L）与突变的积累或/和 23S rRNA C2611T 突变拷贝数的分数相关。BPG-3、4 和 5 中的大多数分离株可与全球和全国范围内流行的已知 AMR 谱系相关联。总之，2017 年 WA 中 AMS 分离株的激增是由于国际 AMS 谱系被引入城市/农村地区，而当地 AMS 谱系主要在偏远地区持续存在。城市/农村地区和偏远地区之间的联系相对较少，但仍需继续监测，以防止 AMR 菌株/谱系进入 WA 的偏远地区。
