A G Taclibon

G A Esparar

L T Sombrero

M U Mondoy

Mrz Capeding

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1 
 
 
PNEUMOCOCCAL SEROTYPES AMONG FILIPINO CHILDREN 
ADMITTED IN A TERTIARY CARE CENTER FOR INFECTIOUS 
DISEASES FROM 2000 TO 2005 
 
MRZ Capeding*, LT Sombrero*, GA Esparar*, MU Mondoy*, AG Taclibon* 
 
ABSTRACT 
Streptococcus pneumoniae (SP) infections 
cause substantial morbidity and mortality 
especially in young children; therefore, 
prevention is of importance. Knowledge of 
the prevailing pneumococcal serotypes is 
necessary to formulate recommendations 
regarding use of pneumococcal conjugate 
vaccine.  Fifty four invasive isolates from 
patients admitted to the Research Institute for 
Tropical Medicine, one of the tertiary care 
centers for infectious diseases of the 
Department of Health, during the years 
January 2000 to August 2005 were serotyped.  
Hospital medical records of children with 
invasive SP infections were reviewed. 
Thirty of the 54 isolates were available for 
serotyping and represented 11 serotypes. 
Three serotypes/serogroup (6,18,14) were 
responsible  for 50% of infections. Sixty  
seven percent of the serotypes were included 
in the 7–valent pneumococcal  conjugate 
vaccine. Invasive pneumococcal disease was 
an important cause of infections particularly 
in children less than 2 years of age. The most 
common diagnosis of invasive pneumococcal 
disease was pneumonia. There was significant 
mortality associated with IPD. Immunization 
with pneumococcal conjugate vaccine will 
help prevent infections in Filipino children.  
 
INTRODUCTION 
     Streptococcus pneumoniae, the 
pneumococcus, is one of the most common 
etiologic agents of community-acquired 
pneumonia, febrile bacteremia, and bacterial 
meningitis in children.  It accounts for over 
1 million deaths annually among children  
__________________ 
Keywords: streptococcus pneumoniae, pneumococcal 
serotypes, invasive pneumococcal disease 
*Research Institute for Tropical Medicine, Muntinlupa 
City, Metro Manila, Philippines 
 
 
worldwide, mostly in developing countries, 
where the pneumococcus remains as one of 
the most clinically relevant pathogens
1
.  In 
the Philippines, pneumonia is the number 
one cause, while meningitis and septicemia 
are among the top 10 leading causes of 
mortality among children ages 1to 4 years
2
. 
Use of antibiotics and immunization 
against pneumococcal diseases is, therefore, 
the cornerstone in managing infections 
caused by invasive Streptococcus 
pneumoniae.  Despite the discovery and 
introduction of newer antibiotics that act 
against Streptococcus pneumoniae, drug-
resistance has been reported in ever 
increasing numbers, causing a major 
worldwide concern 
3, 4
. 
Growing resistance to drug seen in the 
pneumococcus underscores the importance 
of immunization to prevent diseases caused 
by invasive Streptococcus pneumoniae.  The 
World Health Organization (WHO) and the 
United Nations Children’s Fund (UNICEF) 
are spearheading a more comprehensive and 
aggressive immunization strategy that aims 
to increase coverage and reduce mortality 
by, among other initiatives, introducing new 
vaccines
5
.  This global program is especially 
important to developing countries, like the 
Philippines, where morbidity and mortality 
rates are high.  As a result, the use of 
pneumococcal conjugate vaccines has been 
newly instituted in this country.      
Information on the prevailing types of 
Streptococcus pneumoniae is necessary to 
guide health care practitioners in their 
decision concerning use of such vaccines.  
This report describes and characterizes the 
pneumococcal serotypes seen among 
Filipino children with infectious diseases 
PIDSP Journal 2009 Vol 10 No.1 
Copyright ® 2009 
2 
 
and admitted at a tertiary care center in the 
Philippines.  
 
MATERIALS AND METHODS 
From   January 2000 to December 2005, 
54 invasive Streptococcus pneumoniae 
isolates were identified by the Department 
of Microbiology from children admitted at 
the Research Institute for Tropical Medicine 
(RITM), one of the tertiary care centers for 
infectious diseases of the Department of  
Health.  The identity of the isolates was 
confirmed by colony morphology, Gram’s 
stain, and susceptibility to 
ethylhydroxycuprein (optochin).  The 
isolates were stored in skim milk at -70
0
C 
until further examination. 
Streptococcus pneumoniae was 
serotyped using the WHO standard method 
of employing Quellung reaction with the use 
of specific antisera from the Staten’s 
Seruminstitut (Copenhagen), Denmark.  
Antimicrobial susceptibility testing was 
done by the Kirby Bauer disk diffusion 
method on Mueller Hinton agar enriched 
with 5% sheep blood.  The following 
antimicrobial agents were tested: penicillin, 
tetracycline, ofloxacin, trimethroprim-
sulfamethoxazole, chloramphenicol, 
rifampicin, vancomycin, erythromycin, and 
clindamycin.  The methodology for 
determining antimicrobial resistance by Disk 
Diffusion Method was adapted from the 
Clinical Laboratory Standards Institute 
(CLSI) antimicrobial susceptibility testing 
standards
6
.    
The median age of patients was 6 
months (range: 1 month to 11 years); 22 
(73%) were male.  Twenty-seven (90%) of 
the patients were <2 years of age and 77% 
were <1 year of age.  Diagnoses were as 
follows: bacteremic pneumonia in 52%, 
meningitis in 30%, measles-associated 
complicated pneumonia in 11%, and 
bacteremia in 7%.  Nine of the 27 patients 
died, giving a mortality rate of 33%.   
 
RESULTS 
Thirty of the 54 isolates were available 
for serotyping and represented 11 serotypes 
(see Table 1).  Three serotypes—6, 18, and 
14, were responsible for 50% of infections.  
Sixty-seven percent of the serotypes were 
included in the 7-valent pneumococcal 
conjugate vaccine.   
 
Table 1: Serotype Distribution of Invasive 
Streptococcus pneumoniae in Filipino 
Children (RITM, 2000 - 2005). 
SEROTYPE NUMBER (%) 
6 * 6 (20) 
18 * 5 (17) 
14 * 4 (13.3) 
5 4 (13.3) 
9 * 3 (10) 
20 3 (10) 
1 1 (3.3) 
2 1 (3.3) 
4 * 1 (3.3) 
19 * 1 (3.3) 
38 1 (3.3) 
TOTAL 30 (100) 
*Serotypes included in 7-valent 
pneumococcal conjugate vaccine 
 
     Of the 54 isolates, the resistance rates 
were as follows: penicillin at 3.7%; 
tetracycline at 3.7%; and trimethroprim-
sulfamethoxazole at 22.2% (intermediate 
and resistant categories were 18.5% and 
3.7%, respectively).  No resistance was 
observed with chloramphenicol, 
erythromycin, ofloxacin, rifampicin, 
clindamycin, and vancomycin.  No specific 
serotype was identified with any particular 
antibiotic since there were only a few 
resistant isolates. 
 
DISCUSSION 
Information on the population-based 
incidence of Streptococcus pneumoniae in 
the country would be ideal.  However, such 
information is unavailable in the 
Philippines.  Nevertheless, Streptococcus 
pneumoniae, together with Haemophilus 
influenzae, continues to be one of the most 
important causes of severe pneumonia and 
bacterial meningitis in Filipino children 
7,8, 9
.  
Because the predominant pneumococcal 
serotypes vary from country to country, 
3 
 
country-specific knowledge of serotypes is 
crucial
10, 11, 12
.  From 1988 to 1999, the 7-
valent pneumococcal conjugate vaccine 
covered 48% of the isolates
7
.  However, in 
this report, the vaccine yielded 62%.  
Moreover, in the previous study, serotypes 
1, 6 and 23 were the most common
7
.  In 
contrast, this report demonstrated the 
prevalent serotypes to be 6, 18, and 14.  
Serotype 1, predominant in the previous 
study was found only in 1 patient in the 
present one.  Reports of variation in the 
serotype distribution have been noted in the 
past 
13, 14
. 
Significant mortality continues to be 
associated with invasive pneumococcal 
disease.  This report confirms that 
Streptococcus pneumoniae remains to be a 
very important causative agent of invasive 
infections in young children.  Furthermore, 
it substantiates the value of immunization 
with pneumococcal conjugate vaccine 
among Filipino children to reduce overall 
morbidity and mortality.  
 
ACKNOWLEDGEMENTS 
The authors would like to thank the staff 
of the Department of Microbiology of the 
Research Institute for Tropical Medicine.  
This study was supported by a grant from 
Wyeth Philippines, Inc. 
 
REFERENCES 
1. World Health Organization. Immunization, 
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http://www.who.int/vaccines/en/pneumococcus.s
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2. Department of Health.  Child Mortality, 2000.  
Available at: 
http://www.doh.gov.ph/data_stat/html/child_mo
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3. Mastro TD, Ghafoor A, Nomani NK, et al.  
Antimicrobial resistance of pneumococci with acute 
lower respiratory infection in Pakistan.  Lancet. 
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4. Marton A, Gulyas M, Munoz R, Tomas A.  
Extremely high incidence of antibiotic resistance in 
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6. Performance Standards for Antimicrobial 
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7. Capeding MRZ, Sombrero LT, Lucero MG et al.  
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PNEUMOCOCCAL SEROTYPES AMONG FILIPINO CHILDREN ADMITTED IN A TERTIARY CARE CENTER FOR INFECTIOUS DISEASES FROM 2000 TO 2005

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PNEUMOCOCCAL SEROTYPES AMONG FILIPINO CHILDREN ADMITTED IN A TERTIARY CARE CENTER FOR INFECTIOUS DISEASES FROM 2000 TO 2005

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