Demonstration of Virulence Factors in Streptococcus Pneumoniae Isolates from a Tertiary Hospital in South India
Introduction: Streptococcus pneumoniae (pneumococci) colonizes the nasopharynx and 94 different serotypes have been characterized on the basis of the capsular polysaccharides. Nasopharyngeal colonization is documented to be present in children more, than that seen in adults. Pneumococci cause w...
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| Format: | Article |
| Language: | English |
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JCDR Research and Publications Pvt. Ltd.
2017-04-01
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| Series: | National Journal of Laboratory Medicine |
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| Online Access: | http://www.njlm.net/articles/PDF/2225/26740_CE[VSU]_F(GH)_PF1(VsuGH)_PFA(GH)_PF2(VsuGH).pdf |
| _version_ | 1819131757673316352 |
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| author | Jayashree Veerasamy Jayalakshmi Jayarajan |
| author_facet | Jayashree Veerasamy Jayalakshmi Jayarajan |
| author_sort | Jayashree Veerasamy |
| collection | DOAJ |
| description | Introduction: Streptococcus pneumoniae (pneumococci)
colonizes the nasopharynx and 94 different serotypes have been
characterized on the basis of the capsular polysaccharides.
Nasopharyngeal colonization is documented to be present in
children more, than that seen in adults. Pneumococci cause
wide range of infections with marked morbidity among children,
elderly and immuno-compromised patients. The pathogenesis
may be attributed to the virulence factors such as pneumolysin
and autolysin.
Aim: The aim of this study was to demonstrate virulence
genes, pneumolysin (ply) and autolysin (lytA) in pneumococci
isolated from clinical samples and nasopharyngeal carriers by
Polymerase Chain Reaction (PCR).
Materials and Methods: Total 15,473 clinical samples of
sputum, broncho-alveolar lavage, tracheal aspirate, cerebrospinal fluid, blood, ascitic fluid, throat swab, eye discharge,
ear swab and pleural fluid from infected patients, including
nasopharyngeal carriers screened for pneumococci in 600
healthy school children were included in the study. Blood and
CSF isolates were categorized as invasive and those isolates
obtained from other clinical sites as non-invasive, respectively.
Standard methods for characterisation of Streptococcus
pneumoniae such as Gram stain, Optochin sensitivity, bile
solubility, and inulin fermentation was done, with confirmation
by automated Vitek 2. Streptococcus pneumoniae isolated
from positive samples were subjected to molecular detection
of virulence genes lytA and ply coding for autolysin and
pneumolysin respectively.
Results: In all 121 Streptococcus pneumoniae positive isolates
were isolated from clinical specimens including carriers with
isolation rate of 0.81%. Seventy four pneumococci isolates
were randomly selected which were representative of invasive,
non-invasive and carrier isolates. They were screened by PCR
for lytA and ply genes using appropriate primers. All isolates
tested were positive for autolysin (lytA) and 97.2% including the
15 invasive isolates were positive for pneumolysin (ply).
Conclusion: This study concludes that detection of virulence
genes for pneumococci in clinical samples confirms the pathophysiologic consequences of pneumococcal infections. |
| first_indexed | 2024-12-22T09:20:35Z |
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| language | English |
| last_indexed | 2024-12-22T09:20:35Z |
| publishDate | 2017-04-01 |
| publisher | JCDR Research and Publications Pvt. Ltd. |
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| series | National Journal of Laboratory Medicine |
| spelling | doaj.art-7a702a7a977e4c368ba1d4d2734be62d2022-12-21T18:31:12ZengJCDR Research and Publications Pvt. Ltd.National Journal of Laboratory Medicine2277-85512455-68822017-04-0162MO16MO1910.7860/NJLM/2017/26740:2225Demonstration of Virulence Factors in Streptococcus Pneumoniae Isolates from a Tertiary Hospital in South IndiaJayashree Veerasamy0Jayalakshmi Jayarajan1Assistant Professor, Department of Microbiology, Shri Sathya Sai Medical College and Research Institute, Kanchipuram, Tamil Nadu, India.Professor, Department of Microbiology, PSG Institute of Medical Sciences and Research, Coimbatore, India.Introduction: Streptococcus pneumoniae (pneumococci) colonizes the nasopharynx and 94 different serotypes have been characterized on the basis of the capsular polysaccharides. Nasopharyngeal colonization is documented to be present in children more, than that seen in adults. Pneumococci cause wide range of infections with marked morbidity among children, elderly and immuno-compromised patients. The pathogenesis may be attributed to the virulence factors such as pneumolysin and autolysin. Aim: The aim of this study was to demonstrate virulence genes, pneumolysin (ply) and autolysin (lytA) in pneumococci isolated from clinical samples and nasopharyngeal carriers by Polymerase Chain Reaction (PCR). Materials and Methods: Total 15,473 clinical samples of sputum, broncho-alveolar lavage, tracheal aspirate, cerebrospinal fluid, blood, ascitic fluid, throat swab, eye discharge, ear swab and pleural fluid from infected patients, including nasopharyngeal carriers screened for pneumococci in 600 healthy school children were included in the study. Blood and CSF isolates were categorized as invasive and those isolates obtained from other clinical sites as non-invasive, respectively. Standard methods for characterisation of Streptococcus pneumoniae such as Gram stain, Optochin sensitivity, bile solubility, and inulin fermentation was done, with confirmation by automated Vitek 2. Streptococcus pneumoniae isolated from positive samples were subjected to molecular detection of virulence genes lytA and ply coding for autolysin and pneumolysin respectively. Results: In all 121 Streptococcus pneumoniae positive isolates were isolated from clinical specimens including carriers with isolation rate of 0.81%. Seventy four pneumococci isolates were randomly selected which were representative of invasive, non-invasive and carrier isolates. They were screened by PCR for lytA and ply genes using appropriate primers. All isolates tested were positive for autolysin (lytA) and 97.2% including the 15 invasive isolates were positive for pneumolysin (ply). Conclusion: This study concludes that detection of virulence genes for pneumococci in clinical samples confirms the pathophysiologic consequences of pneumococcal infections.http://www.njlm.net/articles/PDF/2225/26740_CE[VSU]_F(GH)_PF1(VsuGH)_PFA(GH)_PF2(VsuGH).pdfautolysinpneumolysinpneumococcivirulence genes |
| spellingShingle | Jayashree Veerasamy Jayalakshmi Jayarajan Demonstration of Virulence Factors in Streptococcus Pneumoniae Isolates from a Tertiary Hospital in South India National Journal of Laboratory Medicine autolysin pneumolysin pneumococci virulence genes |
| title | Demonstration of Virulence Factors in Streptococcus Pneumoniae Isolates from a Tertiary Hospital in South India |
| title_full | Demonstration of Virulence Factors in Streptococcus Pneumoniae Isolates from a Tertiary Hospital in South India |
| title_fullStr | Demonstration of Virulence Factors in Streptococcus Pneumoniae Isolates from a Tertiary Hospital in South India |
| title_full_unstemmed | Demonstration of Virulence Factors in Streptococcus Pneumoniae Isolates from a Tertiary Hospital in South India |
| title_short | Demonstration of Virulence Factors in Streptococcus Pneumoniae Isolates from a Tertiary Hospital in South India |
| title_sort | demonstration of virulence factors in streptococcus pneumoniae isolates from a tertiary hospital in south india |
| topic | autolysin pneumolysin pneumococci virulence genes |
| url | http://www.njlm.net/articles/PDF/2225/26740_CE[VSU]_F(GH)_PF1(VsuGH)_PFA(GH)_PF2(VsuGH).pdf |
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