Skip to content

Research at St Andrews

The adaptive potential during nasopharyngeal colonisation of Streptococcus pneumoniae

Research output: Contribution to specialist publicationArticle


Adaptation to host defences and antimicrobials is critical for Streptococcus pneumoniae (the pneumococcus) during colonisation of the nasopharynx – its only ecological habitat. The pneumococcus is highly transformable with the genome between different strains varying widely in both gene content and gene
sequence. Thus, mixed strains colonising together will expand the genetic reservoir – ‘‘supragenome’’ for this highly transformable microorganism, increasing its adaptive potential.
The extent of the phenotypic and genotypic diversity of strains co-colonising in the nasopharynx was determined. In contrast to most carriage studies, which characterise single colonies, a systematic analysis of up to 20 colonies per colonisation was undertaken in Tanzanian children for 12 months. The serotype
was determined by conventional serology and confirmed by DNA-based methods. The antibiotype for penicillin and co-trimoxazole was determined from the minimum inhibitory concentration determined by E-test. As representative of the genotype of strains the sequence types (STs) was determined by multilocus sequence typing (MLST).
Of 61 colonisation events studied, seven (11.5%) had strains expressing multiple serotypes, with a maximum of five serotypes detected. Four colonisation events also had co-colonisation of penicillin and/or cotrimoxazole susceptible and non-susceptible pneumococci. Sequence typing revealed that 58% were unique to our cohort. Simultaneous colonisation of up to six STs with two expressing serotype 6B was seen. Re-isolation of either the same or different strains of serotype 6B was seen. Genetically related single-locus and double-locus variants were identified in our cohort that differed by multiple nucleotides.
Multiple colony characterisation revealed phenotypic and genetic evidence of microevolution and a greater diversity of pneumococcal strains colonising together than previously observed, thus increasing the potential to adapt in response to the host environment during colonisation.


Original languageEnglish
Number of pages7
Issue number8
Specialist PublicationInfection Genetics and Evolution
Publication statusPublished - 2011

    Research areas

  • evolution, Streptococcus pneumoniae, antibiotic resistance, ecology, multi-locus sequence typing

Discover related content
Find related publications, people, projects and more using interactive charts.

View graph of relations

Related by author

  1. Can phenotypic data complement our understanding of antimycobacterial effects for drug combinations?

    Kloprogge, F., Hammond, R., Copas, A., Gillespie, S. H. & Della Pasqua, O., 25 Aug 2019, In : Journal of Antimicrobial Chemotherapy.

    Research output: Contribution to journalArticle

  2. Toxicity related to standard TB therapy for pulmonary tuberculosis and treatment outcomes in the REMoxTB study according to HIV status

    Tweed, C. D., Crook, A. M., Dawson, R., Diacon, A. H., McHugh, T. D., Mendel, C. M., Meredith, S. K., Mohapi, L., Murphy, M. E., Nunn, A. J., Phillips, P. P. J., Singh, K. P., Spigelman, M. & Gillespie, S. H., 14 Aug 2019, In : BMC Pulmonary Medicine. 19, 9 p., 152.

    Research output: Contribution to journalArticle

  3. Model-based relationship between the molecular bacterial load assay and time-to-positivity in liquid culture

    Svensson, R. J., Sabiiti, W., Kibiki, G. S., Ntinginya, N. E., Bhatt, N., Davies, G., Gillespie, S. H. & Simonsson, U. S. H., 29 Jul 2019, In : Antimicrobial Agents and Chemotherapy. Early

    Research output: Contribution to journalArticle

  4. Molecular bacterial load assay (MBLA) concurs with culture on the NaOH-induced Mycobacterium tuberculosis loss of viability

    Mtafya, B., Sabiiti, W., Sabi, I., John, J., Sichone, E., Ntinginya, N. E. & Gillespie, S. H., 25 Jun 2019, In : Journal of Clinical Microbiology. 57, e01992-18.

    Research output: Contribution to journalArticle

  5. Heat-inactivation renders sputum safe and preserves Mycobacterium tuberculosis RNA for downstream molecular tests

    Sabiiti, W., Azam, K., Esmeraldo, E., Bhatt, N., Rachow, A. & Gillespie, S. H., Mar 2019, In : Journal of Clinical Microbiology. 57, 4, 8 p., e01778-18.

    Research output: Contribution to journalArticle

Related by journal

  1. Population genetic analysis of large sequence polymorphisms in Plasmodium falciparum blood-stage antigens

    Ahouidi, A. D., Bei, A. K., Neafsey, D. E., Sarr, O., Volkman, S., Milner, D., Cox-Singh, J., Ferreira, M. U., Ndir, O., Premji, Z., Mboup, S., Duraisingh, M. T. & Cox Singh, J., Mar 2010, In : Infection Genetics and Evolution. 10, 2, p. 200-206 7 p.

    Research output: Contribution to journalArticle

ID: 14507814