Abstract：
The heteroresistance of polymyxin B, a last-resort antibiotic used to treat many serious bacterial infections, may lead to antibiotic treatment failure. However, polymyxin B-heteroresistant isolates are rare in individuals living in the community. We report a polymyxin B-heteroresistant hypervirulent Klebsiella pneumoniae (hvKP) isolate from an individual in the community with asymptomatic bacteriuria.
The NYTJ35 isolate had multiple virulence genes that encoded a mucoid phenotype regulator (rmpA), aerobactin (iucABCD-iutA), salmochelin (iroBCDN), yersiniabactin (irp1-2 and ybtAEPQSTUX), and a truncated rmpA2. Infection of galleria mellonella larvae indicated the isolate was hypervirulent. Antimicrobial susceptibility testing showed it was susceptible to all tested antibiotics except polymyxin B. The proportion of surviving bacteria was 1.2 × 10- 7 based on the population analysis profile (PAP) method, suggesting the presence of polymyxin B heteroresistance. The isolate was not hypermucoviscous, but it was a strong biofilm producer. It had capsular serotype K1 and belonged to sequence type 23 (ST23). The isolate also had the D150G substitution in phoQ, which is known to confer polymyxin B resistance.
We identified the co-occurrence of hypervirulence and polymyxin B heteroresistance in a K. pneumoniae isolate from an individual with asymptomatic bacteriuria. We suggest the use of increased screening for hvKP in individuals living in the community.
The NYTJ35 isolate had multiple virulence genes that encoded a mucoid phenotype regulator (rmpA), aerobactin (iucABCD-iutA), salmochelin (iroBCDN), yersiniabactin (irp1-2 and ybtAEPQSTUX), and a truncated rmpA2. Infection of galleria mellonella larvae indicated the isolate was hypervirulent. Antimicrobial susceptibility testing showed it was susceptible to all tested antibiotics except polymyxin B. The proportion of surviving bacteria was 1.2 × 10- 7 based on the population analysis profile (PAP) method, suggesting the presence of polymyxin B heteroresistance. The isolate was not hypermucoviscous, but it was a strong biofilm producer. It had capsular serotype K1 and belonged to sequence type 23 (ST23). The isolate also had the D150G substitution in phoQ, which is known to confer polymyxin B resistance.
We identified the co-occurrence of hypervirulence and polymyxin B heteroresistance in a K. pneumoniae isolate from an individual with asymptomatic bacteriuria. We suggest the use of increased screening for hvKP in individuals living in the community.
摘要：
多粘菌素B的异质抗性，一种最后的抗生素，用于治疗许多严重的细菌感染，可能导致抗生素治疗失败。然而,多粘菌素B异源耐药分离株在社区中的个体中很少见。我们报告了多粘菌素B异源耐药的高毒力肺炎克雷伯菌（hvKP）从社区中无症状菌尿的个体中分离出。
NYTJ35分离株具有多个编码粘液表型调节因子（rmpA）的毒力基因，aerobactin(iucAB-iutA)，Salmochelin（iroBCDN），Yersiniabactin（irp1-2和ybtAEPQSTUX），和截断的rmpA2。淋球菌幼虫的感染表明该分离株具有高毒力。药敏试验表明，除多粘菌素B外，对所有试验抗生素均敏感。根据群体分析概况（PAP）方法，存活细菌的比例为1.2×10-7。提示多粘菌素B异质抗性的存在。分离物没有高粘膜粘性,但它是一个强大的生物膜制作人。它具有荚膜血清型K1，属于序列类型23（ST23）。该分离物在phoQ中也具有D150G取代,已知赋予多粘菌素B抗性。
我们确定了在来自无症状菌尿个体的肺炎克雷伯菌分离物中，高毒力和多粘菌素B异质耐药的同时发生。我们建议在社区中生活的个人中增加对hvKP的筛查。
NYTJ35分离株具有多个编码粘液表型调节因子（rmpA）的毒力基因，aerobactin(iucAB-iutA)，Salmochelin（iroBCDN），Yersiniabactin（irp1-2和ybtAEPQSTUX），和截断的rmpA2。淋球菌幼虫的感染表明该分离株具有高毒力。药敏试验表明，除多粘菌素B外，对所有试验抗生素均敏感。根据群体分析概况（PAP）方法，存活细菌的比例为1.2×10-7。提示多粘菌素B异质抗性的存在。分离物没有高粘膜粘性,但它是一个强大的生物膜制作人。它具有荚膜血清型K1，属于序列类型23（ST23）。该分离物在phoQ中也具有D150G取代,已知赋予多粘菌素B抗性。
我们确定了在来自无症状菌尿个体的肺炎克雷伯菌分离物中，高毒力和多粘菌素B异质耐药的同时发生。我们建议在社区中生活的个人中增加对hvKP的筛查。
