The Impact of the 7-Valent Pneumococcal Conjugate Vaccine on Nasopharyngeal Carriage of Streptococcus pneumoniae in Infants of Ajlun Governorate in Jordan

Jordan Journal of Biological Sciences

Adnan Al-Lahham¹ 

关键词: Streptococcus pneumoniae;    Carriage;    Resistance;    Pneumococcal Conjugate Vaccines.;   

DOI  :  

学科分类：生物科学（综合）

来源: Hashemite University, Deanship of Research and Higher Studies

【 摘 要 】

Streptococcus pneumoniae colonization is a serious problem since dissemination to other organs in the body can cause serious infections. This study investigates the impact of the pneumococcal conjugate vaccine (PCV7) on pneumococcal carriage and resistance in healthy infants in the rural areas of Ajlun, Jordan. 415 infants younger than two years of age were selected for this study. The vaccination was given at ages 2, 4 and 10 months between April 2009 and July 2010 (Scheme 2+1). Nasopharyngeal (NP) swabs were taken at the first vaccination (phase one), the third vaccination (phase two), and also three months after the last vaccination (phase three). Pneumococcal isolates were identified according to morphology, bile solubility, and optochin sensitivity. Antimicrobial susceptibility was tested via the micro-broth dilution method and serotyping by the (Neufeld) Quellung reaction. At the first vaccination, carriage in two-month old infants was 26.3%. At the third vaccination, carriage in ten-month–old infants was 29.9%, and at three months after their last vaccinations it was 29.4%. Twenty cases were found positive for all the three nasopharyngeal swabs (5.1%). At the end of the study 241/415 cases (58.1%) were carriers. Resistance rates were as follows: (intermediate and resistant): penicillin (84.0%), cefotaxime (5.6%), clarithromycin (47.2%), clindamycin (25.6%), trimethoprim-sulfamethoxazole (59%), and tetracycline (39%). Multidrug resistance rate was 39.5% for phase one, 48.4% for phase two, and 46.7% for phase three. Frequent serotypes at the time of the first vaccination were: 6A (14.7%), 19F (12.8%), 6B, 23F, and 15B at 6.4% each, and 11A (5.5%). Frequent serotypes after the last vaccination were: 11A (12.3%), 19A (10.7%), 6A (9.0%), and 19F (8.2%). The prevalence of vaccine serotypes (4, 6B, 9V, 14, 19F and 23F) at phase one (0.9%, 6.4%, 1.8%, 3.7%, 12.8%, 6.4%, respectively) was reduced at phase three (0.0%, 2.5%, 0.0%, 3.3%, 8.2%, 0.8%, respectively). Serotype 18C was not identified. An increase of 19A in phase one from 2.8% to 10.7% at phase three was observed. The impact of vaccination was an observed reduction in the resistance to penicillin, cefotaxime, clarithromycin, and clindamycin by 5.9%, 2.4%, 11.4%, and 18.3%, respectively. Coverage of the PCV7 and PCV13 three months after receiving the third injection was 27.8% and 49.4% respectively. High carriage and resistance rates were observed among the infants. Vaccine administration reduced pneumococcal carriage and antimicrobial resistance among the infants.

【 授权许可】

CC BY