|Year : 2017 | Volume
| Issue : 4 | Page : 607-609
Demographic profile of healthy children with nasopharyngeal colonisation of Streptococcus pneumoniae: A research paper
Radhika Raman1, Janani Sankar2, Sulochana Putlibai3, Vaidehi Raghavan4
1 Department of Pediatric Emergency Medicine, CHILDS Trust Medical Research Foundation, Kanchi Kamkoti CHILDS Trust Hospital, Chennai, Tamil Nadu, India
2 Department of Pediatric Medicine, CHILDS Trust Medical Research Foundation, Kanchi Kamkoti CHILDS Trust Hospital, Chennai, Tamil Nadu, India
3 Department of Microbiology and Laboratory Services, CHILDS Trust Medical Research Foundation, Kanchi Kamkoti CHILDS Trust Hospital, Chennai, Tamil Nadu, India
4 Department of Microbiology and Laboratory Services, Sundaram Medical Foundation, Chennai, Tamil Nadu, India
|Date of Web Publication||1-Feb-2018|
Dr. Radhika Raman
Department of Pediatric Emergency Medicine, CHILDS Trust Medical Research Foundation, Kanchi Kamkoti CHILDS Trust Hospital, Nungambakkam, Chennai - 600 034, Tamil Nadu
Source of Support: None, Conflict of Interest: None
Background: Pneumonia is a preventable cause of mortality in children. Streptococcus pneumoniae colonising the nasopharynx of healthy children can cause invasive diseases and the serotype distribution of colonisation isolates should be an indicator of invasive disease, antibiotic resistance profiles, and potential vaccine coverage. Identifying factors influencing nasopharyngeal colonisation, the serotypes and antimicrobial resistance pattern can improve rational preventive strategies. Objectives: Identify risk factors associated with nasopharyngeal colonisation of S.pneumoniae in healthy children between 6 months to 5 years of age. Determine the serotype and antibiotic sensitivity of S. pneumoniae isolated from nasopharynx of healthy children. Methods: This prospective observational included 500 healthy children, 6months to 5 years of age. Demographic features of the study population, the serotypes and antimicrobial sensitivity pattern of S.Pneumoniae isolated from cultures of nasopharyngeal swabs were subjected to statistical analysis. Results: S. pneumoniae was isolated in 9% of 450 children. Increased nasopharyngeal carriage rate was associated with overcrowding 48.8% and poor ventilation 35.5%. 6B (n=16) was the most common serotype isolated. 69% were serogroups known to cause invasive disease All S. pneumoniae isolates were susceptible to vancomycin and linezolid. Antimicrobial susceptibility of PCV 7 serotypes were greater than non PCV 7 serotypes for almost all antimicrobials tested. Penicillin resistance was 11 % and MDR 51%
Keywords: Colonization, pneumococci, resistance, serotypeKey words: Colonization, pneumococci, resistance, serotype
|How to cite this article:|
Raman R, Sankar J, Putlibai S, Raghavan V. Demographic profile of healthy children with nasopharyngeal colonisation of Streptococcus pneumoniae: A research paper. Indian J Med Microbiol 2017;35:607-9
|How to cite this URL:|
Raman R, Sankar J, Putlibai S, Raghavan V. Demographic profile of healthy children with nasopharyngeal colonisation of Streptococcus pneumoniae: A research paper. Indian J Med Microbiol [serial online] 2017 [cited 2020 Sep 22];35:607-9. Available from: http://www.ijmm.org/text.asp?2017/35/4/607/224411
| ~ Introduction|| |
Streptococcus pneumoniae colonising the nasopharynx can cause invasive diseases including pneumonia, a preventable cause of death in children., Locally prevalent pneumococcal serotypes (STs), risk factors and pattern of drug resistance help formulating rational therapeutic and preventive strategies.,
- To identify risk factors associated with nasopharyngeal (NP) colonisation of Streptococcus pneumoniae in healthy children between 6 months and 5 years of age
- To determine the ST and antibiotic sensitivity of S. pneumoniae isolated from the nasopharynx of healthy children.
| ~ Methods|| |
This prospective observational study between March 2012 and August 2013 included 500 healthy children, 6 months to 5 years of age attending the immunisation clinic of a paediatric hospital in South India. The study was approved by the Institutional Review Board and Ethics Committee of the hospital. Children who received antibiotics in the preceding 3 weeks of enrolment or pneumococcal vaccine in the past and those with chronic illness, underlying immune deficiency, bleeding disorder, malformation or injury of the nasopharynx were excluded from the study. Demographic and clinical characteristics were obtained using a detailed questionnaire. Overcrowding was defined using the WHO standards. NP swabs were obtained with paediatric calcium alginate swabs on a flexible ultrafine aluminium shaft (Thermo Fisher, USA) using the standard technique.
Isolation and serotyping
Catalase-negative Gram-positive colonies were confirmed as S. pneumoniae, based on susceptibility to optochin and bile solubility. Isolates were serotyped by latex agglutination method using Pneumococcus 7-valent Latex Kit (Statens Serum Institut, Denmark) which contains nine vials of latex particles coated with pneumococcal antiserum raised in rabbits.
Antimicrobial susceptibility was tested by Kirby-Bauer method and the results were interpreted as per the CLSI guidelines. Penicillin minimum inhibitory concentration (MIC) was determined by E-test  for penicillin-resistant strains. Antibiotic discs for susceptibility testing included oxacillin (1 μg – penicillin susceptibility), vancomycin, erythromycin, tetracycline, levofloxacin, co-trimoxazole, chloramphenicol, clindamycin and linezolid.
Chi-square test, in SPSS, was used for statistical analysis.
| ~ Results|| |
S. pneumoniae was isolated in 45 (9%) of 450 children, of whom 80.6% were toddlers, 60% females and 40% males. Increased NP carriage rate was associated with overcrowding 48.8% (22) and poor ventilation 35.5% (16) [Table 1]. Passive smoking 6.7%, day care 2.2% and type of housing and predisposing factors such as otorrhoea, meningitis, pneumonia and head injury were not associated with higher carriage rate of S. pneumoniae. NP carriage was not different whether children were exclusively breastfed (43.6%) or not (56.4%).
|Table 1: Risk factors associated with nasopharyngeal colonisation of Streptococcus pneumoniae|
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6B (16) was the most common ST isolated [Figure 1]. Sixty-nine per cent were serogroups (SGs) known to cause invasive disease. Sixteen infants (35.5%) had ST 6B and two siblings 19F. Overcrowding and poor ventilation were associated factors in 49% of children with STs 6B and 23F.
All 45 (100%) S. pneumoniae isolates were susceptible to vancomycin, and linezolid susceptibility was 98%, 89%, 87%, 66%, 58%, 51% and 33%, respectively, for levofloxacin, penicillin, chloramphenicol, clindamycin, tetracycline, erythromycin and co-trimoxazole Antimicrobial susceptibility of pneumococcal conjugate vaccines 7 (PCV 7) STs were greater than non-PCV 7 STs for all antimicrobials tested, except chloramphenicol [Figure 2]. Penicillin resistance was 11%. Multidrug resistance (MDR) was 51% with 74% of the MDR isolates resistant to erythromycin and co-trimoxazole. Fifty-two per cent of children with MDR were between 1 and 5 years of age and 39% were infants.
|Figure 2: Comparison of antimicrobial susceptibility between PCV7 and non PCV7 serotypes |
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| ~ Discussion|| |
NP colonisation in toddlers and infants is a potential source for horizontal transmission in the community. Risk factors for colonisation such as passive smoking, day-care, otorrhoea, head injury and meningitis and the NP carriage rate were not in concordance with the similar studies probably due to variation in demography, sampling techniques and size of study population.,,,,,
The SG ST and the most common ST of our isolates varied from those isolated in South and Northeast India.,,,,
Thirty-five (77.7%) STs isolated were PCV 7 and PCV 13 vaccine ST, four of which have been isolated from pneumococcal infections in India., Identifying the STs colonising the nasopharynx in the community is vital for the prevention of disease caused by vaccine STs in vaccinated and in non-vaccinated age groups.,,
Antimicrobial resistance and susceptibility profile of S. pneumoniae colonising and causing invasive disease are an estimate of incidence of resistance in systemic isolates.,, All isolates (100%) were sensitive to vancomycin and linezolid and highly susceptible to levofloxacin. Penicillin resistance, especially intermediate resistance of 23F and 6B, varied from reports available from India and two strains of 'others' ST had high-level resistance to penicillin., Penicillin resistance is associated with treatment failure, increased expenditure and cross-resistance to other antibiotics. Resistance to co-trimoxazole is as high as 81%–94% in India, and we found only 33% were susceptible., Antimicrobial susceptibility of PCV 7 STs was good for all antimicrobials tested, except chloramphenicol; however, judicial use of antimicrobials is important.
MDR 28% for two drugs and 19% for three drugs have been reported from India; however, 51% of our isolates were MDR with resistance to erythromycin and co-trimoxazole combination in 17/23 (73.9%) of MDR isolates. Six isolates each from 6B, 23F and 'others' and three from 19F were MDR.
Isolation of resistant pneumococcal strains from healthy carriers is an indication for active immunisation with a conjugate pneumococcal vaccine to reduce carriage rate of vaccine STs.
| ~ Conclusion|| |
Small sample size from a single urban centre and determining only PCV STs were the limitations.
Overcrowding and poor ventilation probably facilitate NP colonisation with S. pneumoniae, and PCV ST resistant to antimicrobials in the nasopharynx of healthy children is a cause for concern.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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