Bajanca-Lavado Maria Paula, Cavaco Luís, Fernandes Mariana, Touret Tiago, Candeias Catarina, Simões Alexandra S, Sá-Leão Raquel
Haemophilus influenzae Reference Laboratory, Department of Infectious Diseases, National Institute of Health, 1600-046 Lisboa, Portugal.
Laboratory of Molecular Microbiology of Human Pathogens, Instituto de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, 2780-157 Oeiras, Portugal.
Microorganisms. 2022 Oct 4;10(10):1964. doi: 10.3390/microorganisms10101964.
is an important cause of mucosal and invasive infections and a common colonizer of the upper respiratory tract. As there are no recent data on carriage in Portugal, we aimed to characterize carriage samples and investigate possible parallelisms with disease isolates. Between 2016-2019, 1524 nasopharyngeal samples were obtained from children (0-6 years) attending day-care. were serotyped and screened for β-lactamase production. Strains producing β-lactamase and/or those that were encapsulated were further characterized by antibiotype; encapsulated strains were also investigated for MLST and the presence of antimicrobial resistance and virulence genes (extracted from whole genome sequencing). The overall carriage rate was 84.1%. Most isolates (96.7%) were nonencapsulated. Encapsulated strains were of serotypes f (1.8%), e (1.1%), a (0.3%), and b (0.1%). MLST showed clonality within serotypes. Although the lineages were the same as those that were described among disease isolates, colonization isolates had fewer virulence determinants. Overall, 7.5% of the isolates were β-lactamase positive; one isolate had , which has not been previously described in . A single isolate, which was identified as , had an incomplete f-like cap locus. In conclusion, circulation of serotype b is residual. The few encapsulated strains are genetically related to disease-causing isolates. Thus, surveillance of carriage should be maintained.
是黏膜和侵袭性感染的重要病因，也是上呼吸道常见的定植菌。由于目前尚无葡萄牙关于其携带情况的最新数据，我们旨在对携带菌株样本进行特征分析，并调查与疾病分离株可能存在的相似之处。2016年至2019年期间，从日托中心的儿童（0至6岁）中采集了1524份鼻咽样本。对这些样本进行血清分型并检测β-内酰胺酶的产生情况。对产生β-内酰胺酶的菌株和/或被包膜化的菌株进一步进行抗菌型特征分析；对被包膜化的菌株还进行多位点序列分型（MLST）以及抗菌药物耐药性和毒力基因（从全基因组测序中提取）的检测。总体携带率为84.1%。大多数分离株（96.7%）未被包膜化。被包膜化的菌株血清型为f（1.8%）、e（1.1%）、a（0.3%）和b（0.1%）。MLST显示血清型内存在克隆性。尽管这些谱系与疾病分离株中描述的谱系相同，但定植分离株的毒力决定因素较少。总体而言，7.5%的分离株β-内酰胺酶呈阳性；一株分离株具有[未提及具体内容]，此前在[未提及具体内容]中未曾描述过。一株被鉴定为[未提及具体内容]的分离株具有不完整的f样荚膜位点。总之，b血清型的传播较为少见。少数被包膜化的菌株在基因上与致病分离株相关。因此，应继续对其携带情况进行监测。
