Epidemiology and molecular typing of Bordetella pertusis in Greece, 2010-2015

Doctoral Dissertation uoadl:2875463 79 Read counter

Τομέας Υγείας - Μητέρας - Παιδιού
Library of the School of Health Sciences
Deposit date:
Petridou Evangelia
Dissertation committee:
Μαρία Παπαγρηγορίου - Θεοδωρίδου, Ομότιμη Καθηγήτρια, Ιατρική Σχολή, ΕΚΠΑ
Αθανάσιος Μίχος, Αναπληρωτής Καθηγητής, Ιατρική Σχολή, ΕΚΠΑ, Επιβλέπων
Χρήστος Μαυρογιάννης, Καθηγητής, Τμήμα Νοσηλευτικής, ΕΚΠΑ
Χριστίνα Κανακά, Καθηγήτρια, Ιατρική Σχολή ΕΚΠΑ
Κωνσταντίνος Τσουμάκας, Καθηγητής, Τμήμα Νοσηλευτικής, ΕΚΠΑ
Σουλτάνα Σιαχανίδου, Αναπληρώτρια Καθηγήτρια, Ιατρική Σχολή, ΕΚΠΑ
Αθανάσιος Καδίτης, Αναπληρωτής Καθηγητής, Ιατρική Σχολή, ΕΚΠΑ
Original Title:
Επιδημιολογική και εργαστηριακή διερεύνηση του κοκκύτη στα παιδιά
Translated title:
Epidemiology and molecular typing of Bordetella pertusis in Greece, 2010-2015
Despite longstanding vaccination programs, B. pertussis has resurged in industrialized countries since the beginning of the 21st century. Possible causes for the resurgence are improved surveillance and diagnosis, suboptimal vaccine coverage, waning immunity associated with acellular vaccine and bacterial adaptation to vaccine - induced immunity.
Aim: The aim of this study is the epidemiological and the laboratory investigation of pertussis between 2010 - 2015, a period during which vaccination was mandatory with high coverage.
Patients - Methods: Diagnosis of B. pertussis was performed on nasopharyngeal aspirates collected from 1150 children with pertussis symptoms, hospitalized in “Agia Sophia” Athens΄ Children’s Hospital. IS481 / IS1001 / recA real - time Polymerase Chain Reaction was used to detect B. pertussis / parapertussis / holmesii infection in the aforementioned samples. Bacterial sequence polymorphisms were studied by means of multi - locus variable number tandem repeat analysis (MLVA) and sequence - based typing of toxin promotor region (ptP) in a subset of samples derived from specimens positive for B. pertussis.
Results: Out of 1150 samples tested by PCR for Bordetella, 300 were positive for B. pertussis, 32 for B. parapertussis and none for B. holmesii. 88% of the B. pertussis positive cases were infants under 1 year of age, and only 12% were 1-14 years old. The majority of Greek infants infected were under two months of age, below the proposed age of vaccination, as determined by the national health system. Roma and immigrant minorities represent a small percentage of the Greek population but make up 50% of the study population. These last groups were characterized with a low vaccine coverage. A complete MLVA profile was determined in 66 out of 153 samples tested. The B. pertussis MLVA type 27 (MT27) (n = 55/66) was the dominant genotype. All the 25 samples examined by ptP sequencing expressed the ptP3 genotype.
Conclusion: Infants under 2 months of age, too young to have completed primary vaccination schedules, constitute the majority of the population infected by B. pertussis, in the period 2010 - 2015. Higher pertussis burden was also found among Roma and immigrant minorities (probably as a result of absence of immunization and lower socioeconomic conditions). The B. pertussis MT27 and ptP3 genotype are dominant in Greek, Roma and immigrant children hospitalized in Greece. Thus, the predominant MLVA genotype in Greece is similar to that of other countries using acellular vaccines. The genetic diversity of B. pertussis isolates is low, probably due to the use of accelular vaccines and the high vaccination coverage.
Main subject category:
Health Sciences
Bordetella pertusis, molecular typing
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