14th ICID - Poster Abstracts - International Society for Infectious ...

When citing these abstracts please use the following reference:
Author(s) of abstract. Title of abstract [abstract]. Int J Infect Dis 2010;14S1: Abstract number.
Please note that the official publication of the International Journal of Infectious Diseases 2010, Volume 14, Supplement 1
is available electronically on http://www.sciencedirect.com
Final Abstract Number: 80.004
Session: Pediatric and Perinatal Infections
Date: Friday, March 12, 2010
Time: 12:30-13:30
Room: Poster & Exhibition Area/Ground Level
Type: Poster Presentation
DNA amplification and sequence analysis of P1 adhesin gene fragments in M pneumoniae from
pediatric respiratory infections
S. Kumar 1 , S. R. Saigal 1 , G. R. Sethi 1 , R. Chaudhry 2
1 Maulana Azad Medical College, New Delhi, New Delhi, India, 2 All India Institute of Medical
Sciences, New Delhi, New Delhi, India
Background: Mycoplasma pneumoniae is genetically homogeneous and lacks variation. It
possesses a surface-localized protein P1 that clusters at the terminus and is essential for
cytadherence. Direct amplification of P1 gene sequences from clinical specimens, bypassing
culture is advocated for subtyping. This study amplified and sequenced fragment of P1 adhesin
gene of M. pneumoniae employing nasopharyngeal aspirates (NPA) from children with lower
respiratory tract infections.
Methods: A total of 276 children aged 2 months to 12 years, with community acquired lower
respiratory tract infections (LRTIs) were investigated clinically and radiologically. An in-house
PCR to amplify a 543 base pair fragment on P1 adhesin gene in M. pneumoniae using NPA was
standardized. PCR products were purified and sequenced on automated DNA analyzer and
prototype sequences aligned and compared with similar sequences of M. pneumoniae strain M
129 using Clustal W program.
Results: Pneumonia, was documentd in 175(63.3%), bronchiolitis 90(32.6%), virus associated
wheezing 9(3.3%), pneumonia with effusion 2(0.7%) and abnormal chest X –ray findings in
191(69.5%) children. Clinical and radiological features in M. pneumoniae positive and negative
groups were comparable. Twenty one (7.6%) specimens gave positive PCR; 12(57.3%)
specimens yielding weak amplification and in 18(89.5%) specimens PCR positive results were
reproducible. Sequence comparison with Indian strains was not possible because of unavailability
of published data whereas comparison with M. pneumoniae strain M 129(accession number
18639) using CLUSTAL W (1.83) multiple sequence alignment gave 98.07% homogeneity with
one clinical isolate P-1-1, , while with in strain P-1-2, homogeneity was partial.
Conclusion: Our study underlined role of M. pneumoniae in community-acquired LRTIs, even in
children < 12 months of age. Since isolation of M. pneumoniae is rarely attempted, multilocus
sequencing typing system on P1 gene, directly on respiratory specimens, may yield more refined
strain differentiation.