Diphtheria is a vaccine-preventable disease with a high potential for reemergence. One of its causative agents is Corynebacterium diphtheriae, with some strains producing diphtheria toxin. From 2011 to 2019, 57 clinical C. diphtheriae strains were isolated in Austria, either from the respiratory tract or from skin infections. The aim of this study was to investigate the genetic diversity of these C. diphtheriae isolates using whole-genome sequencing. Isolates were characterized by genome-wide comparisons using single nucleotide polymorphism analysis or core genome multilocus sequence typing and by searching sequence data for antimicrobial resistance genes and genes involved in diphtheria toxin production. The genetic diversity among the isolates was high, with no clear distribution over time or place. Corynebacterium belfantii isolates were separated from other strains and were strongly associated with respiratory infections (odds ratio [OR] = 57). Two clusters, limited in time and space, were identified. Almost 40% of strains carried resistance genes against tetracycline or sulfonamides, mostly from skin infections. Microbiological tests showed that 55% of isolates were resistant to penicillin but did not carry genes conferring β-lactam resistance. A diphtheria toxin gene with no nonsynonymous mutation was found in three isolates only. This study showed that sequencing can provide valuable information complementing routine microbiological and epidemiological investigations. It allowed us to identify unknown clusters, evaluate antimicrobial resistance more broadly, and support toxigenicity results obtained by PCR. For these reasons, C. diphtheriae surveillance could strongly benefit from the routine implementation of whole-genome sequencing.

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2011-2019年评估奥地利白喉棒状杆菌临床分离株的遗传多样性

白喉是一种疫苗可预防的疾病，极有可能再次出现。其致病因素之一是白喉棒状杆菌，有些菌株会产生白喉毒素。从2011年到2019年，在奥地利从呼吸道或皮肤感染中分离出57株临床白喉衣原体。这项研究的目的是调查这些白喉衣原体的遗传多样性。分离株使用全基因组测序。通过使用单核苷酸多态性分析或核心基因组多基因座序列类型的全基因组比较，以及通过搜索序列数据以寻找抗菌素抗性基因和白喉毒素产生所涉及的基因，对分离株进行表征。分离株之间的遗传多样性很高，没有随时间或地点的明确分布。比利时棒杆菌分离株与其他菌株分离，并与呼吸道感染密切相关（比值比[OR] = 57）。确定了时间和空间有限的两个集群。几乎40％的菌株携带对四环素或磺酰胺类的抗性基因，主要来自皮肤感染。微生物学测试表明，55％的分离株对青霉素有抗药性，但不携带赋予β-内酰胺抗性的基因。仅在三个分离物中发现了没有非同义突变的白喉毒素基因。这项研究表明，测序可以提供有价值的信息，补充常规的微生物学和流行病学研究。它使我们能够识别未知簇，更广泛地评估抗药性，并支持通过PCR获得的产毒结果。由于这些原因，白喉衣原体的监测可从全基因组测序的常规实施中大大受益。