Indian Journal of Medical Microbiology Medknow Publications on behalf of Indian Association of Medical Microbiology ISSN: 0255-0857 EISSN: 1998-3646 Vol. 30, Num. 1, 2012, pp. 112-112

Indian Journal of Medical Microbiology, Vol. 30, No. 1, January-March, 2012, pp. 112

Correspondence

Serotype 19A Streptococcus pneumoniae among Indian isolates is a cause for concern

M Shariff¹, S Zahoor¹, M Deb²

¹ Department of Microbiology, V. P. Chest Institute, University of Delhi, Delhi - 110 007, India
² Vardhman Mahavir Medical College and Safdarjung Hospital, New Delhi - 110 029, India

Correspondence Address:
M Shariff
Department of Microbiology, V. P. Chest Institute, University of Delhi, Delhi - 110 007
India
malini.shariff@gmail.com

Code Number: mb12026

PMID: 22361777

DOI: 10.4103/0255-0857.93085

Dear Editor,

Streptococcus pneumoniae is found to colonise the nasopharynx of healthy children and adults. The progression of the bacteria from the nasopharynx to the sterile sites such as lungs, blood and brain can lead to serious invasive pneumococcal disease (IPD). Streptococcus pneumoniae is the most commonly identified bacterial cause of meningitis, otitis media and community-acquired pneumonia, and it is a frequent cause of bacteraemia. A 7-valent conjugate vaccine (PCV-7) was introduced in the United States of America in 2000 in order to control the infections caused by this organism. However, this has led to a gradual increase in the prevalence of penicillin-resistant 19A serotype, not present in the PCV-7 vaccine. ^[1] This serotype was previously thought to be a commensal of the upper respiratory tract flora. The prevalence and characterisation of 19A serotype has been reported from USA and Europe where the vaccine is in use. It has also been shown that post PCV-7 the carriage of serotype 19A has increased in the nasopharynx of children. ^[2] Except for Korea and Taiwan, PCV 7 vaccine is not implemented in many Asian countries including India. Even if licensed in some of these countries, the coverage of vaccine is very low. In spite of this, serotype 19A strain is well documented in these countries and predominantly a multi-drug-resistant clone of 19A ST 320 has been reported including India. ^[3]

In the present study done in Delhi, the authors report 5/60 (8%) of isolates to be of 19A serotype. Two of these isolates were from CSF, one from bronchial aspirate and two were from naso- pharynx. The isolates from CSF were sensitive to penicillin, one being resistant to ciprofloxacin. However, the isolate from bronchial aspirate was resistant to penicillin (MIC= 2), erythromycin (MIC>4) and intermediate sensitive to ciprofloxacin (MIC=2). However, 34% of the Asian 19A isolates showed resistance to penicillin. ^[3] The sequence types of two of the isolates revealed in the present study were of types 1796 (2000, USA) and 4217 (1996, India) which were not the same as ST 320 predominantly seen in Asian isolates. ^[3] These observations led us to conclude that 19A serotype has the potential to cause invasive pneumococcal disease and also is showing resistance to penicillin. At present, there are only two studies which have reported 19A serotype in Indian isolates. ^[3],[4] More studies should be undertaken to serotype the Indian isolates so that the prevalence of the 19A and other serotypes can be determined. At present, PCV- 7 vaccine has not been introduced in the extended program of immunisation schedule and its use is optional. If introduction of the vaccine is considered in the future then the prevalence of 19A has to be kept in mind and an appropriate vaccine containing 19A (Prevenar 13) should be considered instead of PCV-7.

References

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