1-5 yaş arası çocuklarda 7 valanlı konjuge pnömokok aşısının nazofarengeal pnömokok taşıyıcılığına etkisi

Abstract

Soon after birth, the nasopharynx of children is colonized by a variety of microorganisms, including commensal bacteria such as Streptococcus Pneumoniae. Colonization is commonly followed by horizontal dissemination of the pathogens to individuals in the direct environment leading to spread within the community.Usually, this colonization is without symptoms but occasionally it can progress to upper, lower respiratory tract or invasive infections causing, acute otitis media, paranasal sinusitis, pneumonia, septicemia, bacterial meningitis, and brain abscess.Seven valent conjugate pneumococcal vaccine (7v-PCV), currently the only commercially available pneumococcal conjugate vaccine, contains 2 ?g of polysaccharide serotypes 4, 9V, 14, 19F and 23F, 2 ?g of serotype 18C and 4 ?g of serotype 6B. Post marketing surveillance studies following its introduction as a universal infant immunization program has shown a large reduction in both invasive and non-invasive disease incidence due to vaccine serotypes in vaccinated individuals.World Health Organization considers that it should be a priority to include this vaccine in national immunization programs, particularly in countries where the mortality rate among children aged < 5 years is above 50 in every 1000 live births or where more then 50.000 children die annually.The aim of our study is to determine the risk factors which facilitate the nasopharyngeal colonization of pneumococci that cause important and lethal diseases and to detect the effect of 7v-PCV on the nasopharyngeal carriage of pneumococci which is an important spreading way in population.Our study was performed between October 2007 and April 2008 at the Maltepe University, Medical Faculty, Department of Pediatrics. Our study included 247 healthy children admitted to our department in this period, at the age of 12?59 months. One hundred and thirty eight of them were vaccinated with seven valent conjugate pneumococcal vaccine and the 109 of children included in the control group were not vaccinated with a 7v-PCV.53The risk factors for S. pneumoniae colonization were evaluated by a questionnaire filled out by the parents before sampling.The questionnaire consisted of questions regarding the time of breast feeding, number of people living in the same house, vaccination against pneumococci, number of the vaccination dose, the time since last vaccination and day care attendanceNasopharyngeal swab samples were collected for culture from vaccinated children and control group. The Kirby-Bauer disc diffusion method was used for antibiotic susceptibilities except for peniciline and ceftriaxone. Minimum inhibition concentrations (MIC) were determined for penicillin and ceftriaxone by E test method.The serotypes of 4, 6b, 9v, 14, 18c, 19f, 23f which are involved in the 7 valent conjugate pneumococcal vaccine were determined by Quellung reaction.From 247 subjects involved in the study, pneumococci were isolated in 32 of them (%12.9). We isolated pneumococci in 14 of 138 vaccinated children (%10.1) and in 18 of (%16) 109 control subjects. There was no statistical difference in rates of isolation of pneumococci between the two groups.Except for living in a crowded family, there was no statistical relationship between isolation of pneumococci from the nasopharynx and risk factors for pneumococcal carriage.The rate of isolation of vaccine type pneumococci in vaccinated children was statistically lower than that of the unvaccinated control group (p=0.035). There was no statistical difference in rates of isolation of nonvaccine type serotypes between the 2 groups. (p=0.11)Four of 30 isolated pneumococci (%13.3) were sensitive to penicillin while 26 of them (%86.7) were not sensitive. Of these 26 isolated serotypes resistant to penicillin, 3 showed high resistance and 23 (%88.4) showed intermediate resistance.There were no statistical difference between 2 groups for penicillin resistance (p=0.29).All pneumococci serotypes were sensitive to ceftriaxone.

Soon after birth, the nasopharynx of children is colonized by a variety of microorganisms, including commensal bacteria such as Streptococcus Pneumoniae. Colonization is commonly followed by horizontal dissemination of the pathogens to individuals in the direct environment leading to spread within the community.Usually, this colonization is without symptoms but occasionally it can progress to upper, lower respiratory tract or invasive infections causing, acute otitis media, paranasal sinusitis, pneumonia, septicemia, bacterial meningitis, and brain abscess.Seven valent conjugate pneumococcal vaccine (7v-PCV), currently the only commercially available pneumococcal conjugate vaccine, contains 2 ?g of polysaccharide serotypes 4, 9V, 14, 19F and 23F, 2 ?g of serotype 18C and 4 ?g of serotype 6B. Post marketing surveillance studies following its introduction as a universal infant immunization program has shown a large reduction in both invasive and non-invasive disease incidence due to vaccine serotypes in vaccinated individuals.World Health Organization considers that it should be a priority to include this vaccine in national immunization programs, particularly in countries where the mortality rate among children aged < 5 years is above 50 in every 1000 live births or where more then 50.000 children die annually.The aim of our study is to determine the risk factors which facilitate the nasopharyngeal colonization of pneumococci that cause important and lethal diseases and to detect the effect of 7v-PCV on the nasopharyngeal carriage of pneumococci which is an important spreading way in population.Our study was performed between October 2007 and April 2008 at the Maltepe University, Medical Faculty, Department of Pediatrics. Our study included 247 healthy children admitted to our department in this period, at the age of 12?59 months. One hundred and thirty eight of them were vaccinated with seven valent conjugate pneumococcal vaccine and the 109 of children included in the control group were not vaccinated with a 7v-PCV.53The risk factors for S. pneumoniae colonization were evaluated by a questionnaire filled out by the parents before sampling.The questionnaire consisted of questions regarding the time of breast feeding, number of people living in the same house, vaccination against pneumococci, number of the vaccination dose, the time since last vaccination and day care attendanceNasopharyngeal swab samples were collected for culture from vaccinated children and control group. The Kirby-Bauer disc diffusion method was used for antibiotic susceptibilities except for peniciline and ceftriaxone. Minimum inhibition concentrations (MIC) were determined for penicillin and ceftriaxone by E test method.The serotypes of 4, 6b, 9v, 14, 18c, 19f, 23f which are involved in the 7 valent conjugate pneumococcal vaccine were determined by Quellung reaction.From 247 subjects involved in the study, pneumococci were isolated in 32 of them (%12.9). We isolated pneumococci in 14 of 138 vaccinated children (%10.1) and in 18 of (%16) 109 control subjects. There was no statistical difference in rates of isolation of pneumococci between the two groups.Except for living in a crowded family, there was no statistical relationship between isolation of pneumococci from the nasopharynx and risk factors for pneumococcal carriage.The rate of isolation of vaccine type pneumococci in vaccinated children was statistically lower than that of the unvaccinated control group (p=0.035). There was no statistical difference in rates of isolation of nonvaccine type serotypes between the 2 groups. (p=0.11)Four of 30 isolated pneumococci (%13.3) were sensitive to penicillin while 26 of them (%86.7) were not sensitive. Of these 26 isolated serotypes resistant to penicillin, 3 showed high resistance and 23 (%88.4) showed intermediate resistance.There were no statistical difference between 2 groups for penicillin resistance (p=0.29).All pneumococci serotypes were sensitive to ceftriaxone.