Institute of Medical Microbiology, Semmelweis University, Budapest, Hungary.
German National Reference Center for Streptococci, Department of Medical Microbiology, University Hospital RWTH Aachen, Aachen, Germany.
PLoS One. 2020 Feb 7;15(2):e0229021. doi: 10.1371/journal.pone.0229021. eCollection 2020.
The nasopharynx can from time to time accommodate otherwise pathogenic bacteria. This phenomenon is called asymptomatic carriage. However, in case of decreased immunity, viral infection or any other enhancing factors, severe disease can develop. Our aim in this study was to survey the nasal carriage rates of four important respiratory pathogens in three different age groups of children attending nurseries, day-care centres and primary schools. This is the first study from Hungary about the asymptomatic carriage of H. influenzae and M. catarrhalis.
Altogether 580 asymptomatic children were screened in three Hungarian cities. Samples were collected from both nostrils with cotton swabs. The identification was based on both colony morphology and species-specific PCRs. Serotyping was performed for S. pneumoniae, H. influenzae and M. catarrhalis. Antibiotic susceptibility was determined with agar dilution, according to the EUCAST guidelines. Clonality was examined by PFGE.
Whereas the carriage rates of S. pneumoniae, H. influenzae and M. catarrhalis clearly decreased with age, that of S. aureus showed an opposite tendency. Multiple carriage was least prevalent if S. aureus was one of the participants. The negative association between this bacterium and the others was statistically significant. For pneumococcus, the overall carriage rate was lower compared to earlier years, and PCV13 serotypes were present in only 6.2% of the children. The majority of H. influenzae isolates was non-typeable and no type b was detected; serotype A was dominant among M. catarrhalis. All four bacteria were more sensitive to antibiotics compared to clinical isolates. No MRSAs were detected, but we found three mupirocin resistant strains. The positive effect of Hib- and PCV-vaccination is undoubted. Continued surveillance of these pathogens is required.
鼻咽部偶尔可容纳其他致病菌。这种现象称为无症状携带。然而，在免疫力下降、病毒感染或任何其他增强因素的情况下，可能会发展为严重疾病。我们的研究目的是调查三种不同年龄组的儿童在托儿所、日托中心和小学时四种重要呼吸道病原体的鼻腔携带率。这是匈牙利首次研究流感嗜血杆菌和卡他莫拉菌的无症状携带情况。
在匈牙利的三个城市，共筛查了 580 名无症状儿童。用棉签从两个鼻孔采集样本。根据菌落形态和种特异性 PCR 进行鉴定。对肺炎链球菌、流感嗜血杆菌和卡他莫拉菌进行血清分型。根据 EUCAST 指南，用琼脂稀释法测定抗生素敏感性。用 PFGE 检查克隆性。
肺炎链球菌、流感嗜血杆菌和卡他莫拉菌的携带率随年龄增长而明显下降，金黄色葡萄球菌则呈相反趋势。如果金黄色葡萄球菌是参与者之一，则多重携带的可能性最小。该细菌与其他细菌之间存在负相关，具有统计学意义。与前几年相比，肺炎球菌的总携带率较低，PCV13 血清型仅存在于 6.2%的儿童中。大多数流感嗜血杆菌分离株不可分型，未检测到 b 型；卡他莫拉菌以 A 型为主。与临床分离株相比，四种细菌对抗生素的敏感性均较高。未发现耐甲氧西林金黄色葡萄球菌（MRSA），但我们发现了三株耐莫匹罗星的菌株。Hib 和 PCV 疫苗接种的积极效果是毋庸置疑的。需要继续监测这些病原体。
