Клинико-эпидемиологические аспекты коклюша у детей в условиях массовой вакцинопрофилактики

The aim of the study was to present clinical, epidemiological and laboratory characteristics of modern pertussis in hospitalized children, as well as to assess the frequency of pertussis infection as an etiological factor of long – term cough in children and adolescents.Materials and methods: medical records of 545 patients hospitalized in Children’s city clinical hospital №5 named after N.F. Filatov (Saint-Petersburg) in the period 2015–2017 were analyzed. Detailed clinical and laboratory analysis with subsequent follow-up of patients was carried out in 80 patients with pertussis aged 1 month to 18 years. The DNA of the causative agents of pertussis infection was identified by PCR using a commercial kit “AmpliSens Bordetella multi-FL” (Moscow); parallel was determined the bacterial load by quantitative PCRRT (real time) using test systems production, Gamaleya Research Institute of Epidemiology and Microbiology (Moscow), allowing to detect a single genome-equivalents (GE) of B. pertussis in smears from the nasopharynx. Pertussis convalescents were examined 1, 3 and 6 months after discharge.Results. Among hospitalized children dominated the first 2 years of life (70.8%), 78% were unvaccinated children. The sources of infection for children of the first two years of life were family members in 77% of cases, for preschoolers-in 67%, for schoolchildren-in 14%. Patients of moderate severity were 81.1%, severe – 10.3%; mild – 7%. Of the specific complications, respiratory rhythm disturbances were notedin 11.6%, including respiratory arrest-in 2.8%; pneumonia of mixed etiology was recorded in 6.2% of cases. Introduction of PCR method allows to increase laboratory confirmation up to 87.2%. In 63.6% of cases pertussis of pertussis were detected by PCR genome-equivalents of DNA in 6 months from hospital discharge. In patients with long – term cough, pertussis wand DNA was detected in preschool children in 11.14% of cases, in patients 7–12 years – in 25.93%, in adolescents-in 20% of cases.Conclusion. Whooping cough is a common infection among schoolchildren and adolescents, despite the high coverage of young children with preventive vaccinations. Pertussis convalescents can release the DNA of the pathogen for a long time, which may have epidemiological significance for unvaccinated and those children and adults, who have lost postvaccinal immunity, in the foci of infection.Цель: представить клинико-эпидемиологические и лабораторные характеристики современного коклюша у госпитализированных детей, а также оценить частоту коклюшной инфекции как этиологического фактора длительного кашля у детей и подростков.Материалы и методы: проанализированы медицинские карты 545 стационарных больных, госпитализированных в ДГКБ № 5 им. Н.Ф. Филатова (СанктПетербург) в период 2015–2017 гг. Детальный клинико-лабораторный анализ с последующим динамическим наблюдением реконвалесцентов проводили у 80 больных коклюшем в возрасте от 1 месяца до 18 лет. ДНК возбудителей коклюшной инфекции выделяли методом ПЦР с использованием коммерческого набора «АмплиСенс ®Bordetella multi-FL» (Москва); параллельно определяли бактериальную нагрузку методом количественного ПЦР-РТ (real time) с помощью тест-системы производства ФНИЦЭМ им. Н.Ф. Гамалеи МЗ РФ (Москва), позволяющей обнаруживать единичные геном-эквиваленты (ГЭ) B. pertussis в мазках из носоглотки. Реконвалесценты коклюша обследованы через 1, 3 и 6 месяцев после выписки.Результаты: среди госпитализированных преобладали дети первых 2 лет жизни (70,8%), 78% составляли непривитые дети. Источниками инфекции для детей первых двух лет жизни были члены семьи в 77% случаев, для дошкольников – в 67%, для школьников – в 14%. Пациенты средней степени тяжести составили 81,1%, тяжелой – 10,3%; легкой – 7%. Из специфических осложнений отмечали нарушения ритма дыхания – в 11,6%, в том числе остановки дыхания – в 2,8%; пневмонии смешанной этиологии регистрировали в 6,2% случаев. Внедрение метода ПЦР позволяет повысить лабораторное подтверждение до 87,2%. У реконвалесцентов коклюша до 6 месяцев от выписки из стационара в 63,6% случаев методом ПЦР-РВ выявлялись геном-эквиваленты ДНК B.Pertussis. У пациентов с длительным кашлем ДНК коклюшной палочки выявляли у дошкольников в 11,14% случаев, у пациентов 7–12 лет – в 25,93%, у подростков – в 20% случаев.Заключение. Коклюш является распространенной инфекцией среди школьников и подростков, несмотря на высокий охват детей раннего возраста профилактическими прививками. Реконвалесценты коклюша могут длительно выделять ДНК возбудителя, что может иметь эпидемиологическое значение для непривитых и утративших поствакцинальный иммунитет детей и взрослых в очагах инфекции

КЛИНИКО-ДИАГНОСТИЧЕСКОЕ ЗНАЧЕНИЕ ГЕНЕТИЧЕСКИХ МАРКЕРОВ BORDETELLA PERTUSSISУ КОНТАКТНЫХ ЛИЦ В СЕМЕЙНЫХ ОЧАГАХ

Goal. Evaluation of duration and frequency of Bordetella pertussis DNA detection in contact persons in family foci of whooping-cough.Materials and methods. 116 persons from 59 family foci of pertussis were examined in contact with sick young children. The DNA of B. pertussis bacteria in nasopharyngeal swabs was detected by real-time PCR (PCR-RV) using a test system developed at Gamaleya Research Institute of Epidemiology and Microbiology (Moscow). The bacterial load and the duration of the release of genomic equivalents (GE) of B. pertussis DNA were determined in dynamics at 1, 3 and 6 months. Results. Among the contact persons in family foci, adults accounted for 59,48%, adolescents and schoolchildren – 10,35% and 12,07% respectively. Cough was absent in 35,34% of contact persons, 20,69% had a rare dry cough, 24,14% had a dry compulsive cough and 19,83% had a typical cough. None of the contact family members were diagnosed with whooping cough, although 64.66% of the patients had clinical signs of the disease, mainly its atypical form (44.83%). Among the carriers of B. pertussis adults accounted for 82.92%, among patients with atypical forms of whooping cough – 51.92%. In the study of nasopharyngeal swabs using the PCR-RV method, it was found that 86.10% of the contact persons detected DNA of B. pertussis. After 3 months in 90% of the contacts, the DNA of pertussis causative agent was detected in a minimum amount of 101-102GE/ml in the sample. After 6 months, B. pertussis was sanitized in 50% of the examined patients. 12.5% of the samples identified avirulent forms of the causative agent of pertussis, formed as a result of movement of IS481 in operon bvgAS.The conclusion. In 86.1% of contact persons in family foci for a long time (from 3 to 6 months), detection of genetic markers of the causative agent of pertussis from the nasopharynx was noted, including 35.34% of those examined in the absence of cough. This, along with the reported genetic mutation in operon bvgAS in 12.5% of cases, can characterize the presence of persistence of B. pertussis, explaining its preservation in circulation in the conditions of mass vaccine prevention.Цель: оценка длительности и частоты выявления ДНК Bordetella pertussis у контактных лиц в семейных очагах коклюша.Материалы и методы. По контакту с больными детьми раннего возраста обследовано 116 лиц из 59 семейных очагов коклюша. ДНК B. pertussis в назофарингеальных мазках выявляли методом ПЦР в режиме реального времени (ПЦР-РВ), используя тест-систему, разработанную в Национальном исследовательском центре эпидемиологии и микробиологии им. почетного академика Н.Ф. Гамалеи (Москва). Бактериальную нагрузку и длительность выявления геномэквивалентов (ГЭ) ДНК B. pertussis определяли в динамике через 1, 3 и 6 месяцев.Результаты. Среди контактных лиц в семейных очагах взрослые составили 59,48%, подростки и школьники – 10,35% и 12,07% соответственно. Кашель отсутствовал у 35,34% контактных лиц, у 20,69% отмечался редкий сухой кашель, у 24,14% – сухой навязчивый и у 19,83% – типичный приступообразный кашель. Ни у кого из контактных членов семей не был диагностирован коклюш, хотя у 64,66% обследуемых лиц имелись клинические признаки заболевания, преимущественно его атипичной формы (у 44,83%). Среди носителей B. pertussis взрослые составили 82,92%, среди заболевших атипичными формами коклюша – 51,92%. При исследовании носоглоточных мазков методом ПЦР-РВ у 86,1% контактных лиц выявили ДНК B. pertussis. Через 3 месяца у 90% контактных продолжали выявлять ДНК в минимальном количестве – 101–102ГЭ/мл в образце. Через 6 месяцев санацию B. pertussis регистрировали у 50% обследованных. В 12,1% исследованных образцов выявлены авирулентные формы возбудителя коклюша, сформированные в результате перемещения IS481 в оперон bvgAS.Заключение. У 86,1% контактных лиц в семейных очагах длительно (от 3 до 6 месяцев) отмечалось вы-явление из носоглотки генетических маркеров возбуди-теля коклюша, в том числе у 35,34% обследованных при отсутствии кашля. Это, наряду с зарегистрирован-ной в 12,5% случаев генетической мутацией в опероне bvgAS, может характеризовать наличие персистенции B. pertussis, объясняя ее сохранение в циркуляции в условиях массовой вакцинопрофилактики

Clinical-epidemiological aspects of whooping cough in children in conditions of mass vaccinoprophylactics

The aim of the study was to present clinical, epidemiological and laboratory characteristics of modern pertussis in hospitalized children, as well as to assess the frequency of pertussis infection as an etiological factor of long – term cough in children and adolescents.Materials and methods: medical records of 545 patients hospitalized in Children’s city clinical hospital №5 named after N.F. Filatov (Saint-Petersburg) in the period 2015–2017 were analyzed. Detailed clinical and laboratory analysis with subsequent follow-up of patients was carried out in 80 patients with pertussis aged 1 month to 18 years. The DNA of the causative agents of pertussis infection was identified by PCR using a commercial kit “AmpliSens Bordetella multi-FL” (Moscow); parallel was determined the bacterial load by quantitative PCRRT (real time) using test systems production, Gamaleya Research Institute of Epidemiology and Microbiology (Moscow), allowing to detect a single genome-equivalents (GE) of B. pertussis in smears from the nasopharynx. Pertussis convalescents were examined 1, 3 and 6 months after discharge.Results. Among hospitalized children dominated the first 2 years of life (70.8%), 78% were unvaccinated children. The sources of infection for children of the first two years of life were family members in 77% of cases, for preschoolers-in 67%, for schoolchildren-in 14%. Patients of moderate severity were 81.1%, severe – 10.3%; mild – 7%. Of the specific complications, respiratory rhythm disturbances were notedin 11.6%, including respiratory arrest-in 2.8%; pneumonia of mixed etiology was recorded in 6.2% of cases. Introduction of PCR method allows to increase laboratory confirmation up to 87.2%. In 63.6% of cases pertussis of pertussis were detected by PCR genome-equivalents of DNA in 6 months from hospital discharge. In patients with long – term cough, pertussis wand DNA was detected in preschool children in 11.14% of cases, in patients 7–12 years – in 25.93%, in adolescents-in 20% of cases.Conclusion. Whooping cough is a common infection among schoolchildren and adolescents, despite the high coverage of young children with preventive vaccinations. Pertussis convalescents can release the DNA of the pathogen for a long time, which may have epidemiological significance for unvaccinated and those children and adults, who have lost postvaccinal immunity, in the foci of infection

CLINICAL-DIAGNOSTIC VALUE OF BORDETELLA PERTUSSIS GENETIC MARKERS IN CONTACT PERSONS IN FAMILIAL FOCI

Goal. Evaluation of duration and frequency of Bordetella pertussis DNA detection in contact persons in family foci of whooping-cough.Materials and methods. 116 persons from 59 family foci of pertussis were examined in contact with sick young children. The DNA of B. pertussis bacteria in nasopharyngeal swabs was detected by real-time PCR (PCR-RV) using a test system developed at Gamaleya Research Institute of Epidemiology and Microbiology (Moscow). The bacterial load and the duration of the release of genomic equivalents (GE) of B. pertussis DNA were determined in dynamics at 1, 3 and 6 months. Results. Among the contact persons in family foci, adults accounted for 59,48%, adolescents and schoolchildren – 10,35% and 12,07% respectively. Cough was absent in 35,34% of contact persons, 20,69% had a rare dry cough, 24,14% had a dry compulsive cough and 19,83% had a typical cough. None of the contact family members were diagnosed with whooping cough, although 64.66% of the patients had clinical signs of the disease, mainly its atypical form (44.83%). Among the carriers of B. pertussis adults accounted for 82.92%, among patients with atypical forms of whooping cough – 51.92%. In the study of nasopharyngeal swabs using the PCR-RV method, it was found that 86.10% of the contact persons detected DNA of B. pertussis. After 3 months in 90% of the contacts, the DNA of pertussis causative agent was detected in a minimum amount of 101-102GE/ml in the sample. After 6 months, B. pertussis was sanitized in 50% of the examined patients. 12.5% of the samples identified avirulent forms of the causative agent of pertussis, formed as a result of movement of IS481 in operon bvgAS.The conclusion. In 86.1% of contact persons in family foci for a long time (from 3 to 6 months), detection of genetic markers of the causative agent of pertussis from the nasopharynx was noted, including 35.34% of those examined in the absence of cough. This, along with the reported genetic mutation in operon bvgAS in 12.5% of cases, can characterize the presence of persistence of B. pertussis, explaining its preservation in circulation in the conditions of mass vaccine prevention

Comparative genome analysis of global and Russian strains of community-acquired methicillin-resistant Staphylococcus aureus ST22, a ‘Gaza clone’

In this study, we identified the relationship between the genetic lineage of community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) sequence type 22 (ST22) from Russia and other regions. Sixty ST22 isolates from Russia were characterised through whole-genome sequencing. To evaluate the phylogenetic relationship of Russian isolates with the global ST22 population, we analysed 1283 genomes obtained from NCBI's GenBank. The phylogenetic tree of the ST22 global population consisted of three main clusters (A, B and C). The first (cluster A) was represented by EMRSA-15 isolates, the second (cluster B) by heterogeneous isolates from different regions harbouring different sets of virulence genes, and the third (cluster C) by isolates from the Middle East previously recognised as ‘Gaza clone’ and similar isolates from Russia. Presence of the toxic shock syndrome toxin (tsst) and elastin-binding protein S (ebpS) genes as well as the hypothetical proteins NCTC13616_00051 and NCTC13616_00047 were the most useful factors in discriminating ST22 lineages. Although the CA-MRSA ‘Gaza clone’ was mainly recovered from carriers, its widespread occurrence is a cause for concern. Differentiation of the ‘Gaza clone’ from other MRSA lineages is necessary for planning infection control measures. © 2020 Elsevier Lt