This work was supported by funding from the Murdoch Childrens Research Institute and the Victorian Government&rsquo;s Operational Infrastructure Support Program.

1. Preparation of Epithelial and Bacterial Cells
<ol>
	<li>Thawing of CCL-23 epithelial cells
	<ol>
		<li>Prewarm Minimum Essential Media (MEM) containing 10% Fetal Bovine Serum (FBS) in a 37 &#176;C water bath for ~30 min.</li>
		<li>Sterilize the tissue culture-approved biosafety cabinet with UV light for at least 10 min before use, and wipe down the work area with 70% ethanol. Wipe the warmed media bottle with 70% ethanol and place in biosafety cabinet.</li>
		<li>Using a 25 ml pipette, transfer 14 ...

<ol>
	<li>O'Brien, K. L., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Burden+of+disease+caused+by+Streptococcus+pneumoniae+in+children+younger+than+5+years:+global+estimates.">Burden of disease caused by Streptococcus pneumoniae in children younger than 5 years: global estimates.</a> Lancet. 374, 893-902 (2009).</li><li>Bogaert, D., de Groot, R., Hermans, P. W. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Streptococcus+pneumoniae+colonisation:+the+key+to+pneumococcal+disease.">Streptococcus pneumoniae colonisation: the key to pneumococcal disease.</a> Lancet Infect. Dis. 4 (04), 144-154 (2004).</li><li>Weinberger, D. M., Malley, R., Lipsitch, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Serotype+replacement+in+disease+after+pneumococcal+vaccination.">Serotype replacement in disease after pneumococcal vaccination.</a> Lancet. 378 (10), 1962-1973 (2011).</li><li>Jacoby, P., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Modelling+the+co-occurrence+of+Streptococcus+pneumoniae+with+other+bacterial+and+viral+pathogens+in+the+upper+respiratory+tract.">Modelling the co-occurrence of Streptococcus pneumoniae with other bacterial and viral pathogens in the upper respiratory tract.</a> Vaccine. 25, 2458-2464 (2007).</li><li>Kwambana, B., Barer, M., Bottomley, C., Adegbola, R., Antonio, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Early+acquisition+and+high+nasopharyngeal+co-colonisation+by+Streptococcus+pneumoniae+and+three+respiratory+pathogens+amongst+Gambian+new-borns+and+infants.">Early acquisition and high nasopharyngeal co-colonisation by Streptococcus pneumoniae and three respiratory pathogens amongst Gambian new-borns and infants.</a> BMC Infect. Dis. 11, (2011).</li><li>Licciardi, P. V., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Protecting+against+pneumococcal+disease:+critical+interactions+between+probiotics+and+the+airway+microbiome.">Protecting against pneumococcal disease: critical interactions between probiotics and the airway microbiome.</a> PLoS Pathog. 8, (2012).</li><li>Popova, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Beneficial+effects+of+probiotics+in+upper+respiratory+tract+infections+and+their+mechanical+actions+to+antagonize+pathogens.">Beneficial effects of probiotics in upper respiratory tract infections and their mechanical actions to antagonize pathogens.</a> J. Appl. Microbiol. 113 (6), 1305-1318 (2012).</li><li>Pracht, D., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=PavA+of+Streptococcus+pneumoniae+modulates+adherence,+invasion,+and+meningeal+inflammation.">PavA of Streptococcus pneumoniae modulates adherence, invasion, and meningeal inflammation.</a> Infect. Immun. 73, 2680-2689 (2005).</li><li>Adamou, J. E., Wizemann, T. M., Barren, P., Langermann, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Adherence+of+Streptococcus+pneumoniae+to+human+bronchial+epithelial+cells+(BEAS-2B).">Adherence of Streptococcus pneumoniae to human bronchial epithelial cells (BEAS-2B).</a> Infect. Immun. 66, 820-822 (1998).</li><li>Wong, S. S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Inhibition+of+Streptococcus+pneumoniae+adherence+to+human+epithelial+cells+in+vitro+by+the+probiotic+Lactobacillus+rhamnosus+GG.">Inhibition of Streptococcus pneumoniae adherence to human epithelial cells in vitro by the probiotic Lactobacillus rhamnosus GG.</a> BMC Res. Notes. 6 (1), 135 (2013).</li><li>Wescombe, P. A., Heng, N. C. K., Burton, J. P., Chilcott, C. N., Tagg, J. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Streptococcal+bacteriocins+and+the+case+for+Streptococcus+salivarius+as+model+oral+probiotics.">Streptococcal bacteriocins and the case for Streptococcus salivarius as model oral probiotics.</a> Future Microbiol. 4, 819-835 (2009).</li><li>Di Pierro, F., Adami, T., Rapacioli, G., Giardini, N., Streitberger, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Clinical+evaluation+of+the+oral+probiotic+Streptococcus+salivarius+K12+in+the+prevention+of+recurrent+pharyngitis+and/or+tonsillitis+caused+by+Streptococcus+pyogenes+in+adults.">Clinical evaluation of the oral probiotic Streptococcus salivarius K12 in the prevention of recurrent pharyngitis and/or tonsillitis caused by Streptococcus pyogenes in adults.</a> Expert. Opin. Biol. Ther. 13 (3), 339-343 (2013).</li><li>Fiedler, T., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Protective+mechanisms+of+respiratory+tract+streptococci+against+Streptococcus+pyogenes+biofilm+formation+and+epithelial+cell+infection.">Protective mechanisms of respiratory tract streptococci against Streptococcus pyogenes biofilm formation and epithelial cell infection.</a> Appl. Environ. Microbiol. 79, 1265-1276 (2013).</li><li>Slotved, H. C., Satzke, C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=In+vitro+growth+of+pneumococcal+isolates+representing+23+different+serotypes.">In vitro growth of pneumococcal isolates representing 23 different serotypes.</a> BMC Res. Notes. 6, 10-1186 (2013).</li><li>Carvalho, M. d. G. S., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Evaluation+and+improvement+of+real-time+PCR+assays+targeting+lytA,+ply,+and+psaA+genes+for+detection+of+pneumococcal+DNA.">Evaluation and improvement of real-time PCR assays targeting lytA, ply, and psaA genes for detection of pneumococcal DNA.</a> J. Clin. Microbiol. 45, 2460-2466 (2007).</li><li>Tonnaer, E. L. G. M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Involvement+of+glycosaminoglycans+in+the+attachment+of+pneumococci+to+nasopharyngeal+epithelial+cells.">Involvement of glycosaminoglycans in the attachment of pneumococci to nasopharyngeal epithelial cells.</a> Microbes Infect. 8, 316-322 (2006).</li><li>Smith-Vaughan, H., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Measuring+nasal+bacterial+load+and+its+association+with+otitis+media.">Measuring nasal bacterial load and its association with otitis media.</a> BMC Ear Nose Throat Disord. 6, (2006).</li><li>Letourneau, J., Levesque, C., Berthiaume, F., Jacques, M., Mourez, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=In+vitro+assay+of+bacterial+adhesion+onto+mammalian+epithelial+cells.">In vitro assay of bacterial adhesion onto mammalian epithelial cells.</a> J. Vis. Exp. , (2011).</li></ol>

A critical portion of this assay is adding the appropriate concentrations of S. salivarius and pneumococci in sections 3.1.7 and 3.1.12. Concentrations are estimated using OD readings but the exact inocula are not determined until plates are counted the following day. For this reason, we recommend performing growth curves to measure OD and viable counts (CFU/ml) over time for all bacterial strains used in the assay to identify the mid-log phase and assist in estimating concentration by OD. Additionally, pneumoco...

Streptococcus pneumoniae (the pneumococcus) is a Gram positive bacterium that can cause infections including pneumonia, otitis media, and meningitis. It is a major cause of disease in children in low-income countries and responsible for an estimated 800,000 deaths of children under the age of five annually1. Pneumococci are frequently carried in the nasopharynx of young children. Although this colonization is generally considered asymptomatic, it precedes pneumococcal infection and serves as a reservoir for the bacteria in human populations2. Pneumococcal conjugate vaccination effectively reduces carriage of the serotypes contained within the vaccine. However, there are over 90 pneumococcal serotypes, and vaccination can lead to serotype replacement, whereby the elimination of vaccine serotypes is followed by a rise in carriage and disease caused by nonvaccine serotypes3. Also, in some high-risk populations, pneumococcal colonization often occurs very early in life, prior to administration of the first vaccine dose4,5. Recently, the use of probiotics has been proposed as an additional strategy to inhibit pneumococcal colonization6,7. In vitro adherence assays have been used to examine pneumococcal adherence8,9. These assays have been adapted to investigate the impact of the probiotic Lactobacillus rhamnosus GG (LGG) on pneumococcal adherence10.
In addition to LGG and other lactic acid bacteria, Streptococcus salivarius, a common resident of the oral cavity, has been investigated as a potential probiotic for the respiratory tract due to its colonization potential and ability to inhibit pneumococci and other respiratory pathogens in vitro11-13. The protocol presented here describes an adherence assay used to investigate the effects of S. salivarius K12 on pneumococcal adherence to the human epithelial cell line CCL-23. Prior to use in the assay, pneumococcal isolates were evaluated for adherence capabilities, as growth and adherence properties can vary substantially among isolates10,14. Growth curves of pneumococci and S. salivarius were performed to determine mid-log phase and estimate concentration (colony forming units or CFU/ml) by optical density (OD, Figure 1).&#160;It is recommended to examine growth by viable count and OD for each isolate prior to use in the assay. This assay can be performed in any laboratory with standard tissue culture facilities and equipment. In this protocol, the effects of three doses of S. salivarius administered 1 hr prior to the addition of pneumococci on the adherence of S. pneumoniae PMP843, a serotype 19F carriage isolate derived from a nasopharyngeal swab, are examined. Two different ways to quantify adherent pneumococci are presented: plating on blood agar to determine viable counts, and DNA extraction and detection of the pneumococcal lytA gene by qPCR15. The basic adherence assay protocol can be easily modified to test different doses or time of administration of probiotics and can also be used with other bacterial strains or species.

<table border="0" cellpadding="0" cellspacing="0" width="1318">
	<colgroup>
		<col />
		<col />
		<col />
		<col span="2" />
	</colgroup>
	<tbody>
		<tr height="42">
			<td height="42" style="height:42px;width:264px;">Minimum Essential Media (MEM)</td>
			<td style="width:155px;">Thermo Fisher Scientific</td>
			<td style="width:147px;">SH30244.01</td>
			<td style="width:377px;"> </td>
			<td style="width:377px;"> </td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:264px;">Fetal Bovine Serum (FBS)</td>
			<td style="width:155px;">Thermo Fisher Scientific</td>
			<td>SH30084.03</td>
			<td></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:264px;">T-75 Flask</td>
			<td style="width:155px;">Nunc</td>
			<td>156472</td>
			<td></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:264px;">CCL-23 cells</td>
			<td style="width:155px;">ATCC</td>
			<td style="width:147px;">CCL-23</td>
			<td style="width:377px;"> </td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:264px;">Trypsin</td>
			<td>Life Technologies</td>
			<td>15090046</td>
			<td></td>
			<td></td>
		</tr>
		<tr height="23">
			<td height="23" style="height:23px;width:264px;">24-well cell culture plate</td>
			<td style="width:155px;">Nunc</td>
			<td style="width:147px;">142475</td>
			<td></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:264px;">Horse blood agar (HBA) plates</td>
			<td style="width:155px;">Oxoid</td>
			<td style="width:147px;">PP2001</td>
			<td>Sheep blood agar plates also acceptable</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:264px;">Todd-Hewitt Broth</td>
			<td style="width:155px;">Oxoid</td>
			<td style="width:147px;">CM0189</td>
			<td></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:264px;">Yeast Extract</td>
			<td style="width:155px;">Beckton Dickinson</td>
			<td style="width:147px;">212750</td>
			<td></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:264px;">Digitonin</td>
			<td style="width:155px;">Sigma-Aldrich</td>
			<td style="width:147px;">D141-100MG</td>
			<td></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:264px;">Disposable cuvettes</td>
			<td style="width:155px;">Kartell</td>
			<td>1938</td>
			<td></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:264px;">Heparin</td>
			<td style="width:155px;">Pfizer</td>
			<td style="width:147px;">2112105</td>
			<td>comes in sterile ampules at 5,000IU/5mL </td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:264px;">sterile spreader</td>
			<td style="width:155px;">Technoplas</td>
			<td style="width:147px;">S10805050</td>
			<td style="width:377px;">alternatively, a glass spreader can be dipped in 96% ethanol and flame sterilized before each use</td>
			<td style="width:377px;"> </td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:264px;">Lysozyme</td>
			<td>Sigma-Aldrich</td>
			<td style="width:147px;">L6876</td>
			<td></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:264px;">Mutanolysin</td>
			<td>Sigma-Aldrich</td>
			<td style="width:147px;">M9901</td>
			<td></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:264px;">Proteinase K</td>
			<td>Qiagen</td>
			<td>19133</td>
			<td></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:264px;">SDS 20% solution</td>
			<td>Ambion </td>
			<td style="width:147px;">AM9820</td>
			<td></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:264px;">RNase A</td>
			<td>Qiagen</td>
			<td style="width:147px;">19101</td>
			<td></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:264px;">QIAamp DNA mini-kit (250)</td>
			<td>Qiagen</td>
			<td style="width:147px;">51306</td>
			<td></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:264px;">LytA F primer</td>
			<td>Sigma-Aldrich</td>
			<td style="width:147px;">Custom made</td>
			<td>5&#39; -&#62; 3&#39; sequence ACGCAATCTAGCAGATGAAGCA</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:264px;">LytA R primer</td>
			<td>Sigma-Aldrich</td>
			<td style="width:147px;">Custom made</td>
			<td>5&#39; -&#62; 3&#39; sequence TCGTGCGTTTTAATTCCAGCT</td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:264px;">LytA probe</td>
			<td>Eurogentec</td>
			<td style="width:147px;">Custom made</td>
			<td colspan="2">5&#39; -&#62; 3&#39; sequence Cy5-TGCCGAAAACGCTTGATACAGGGAG-BHQ3, alternative fluorophores can be used</td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:264px;">Nuclease free water</td>
			<td>Ambion</td>
			<td style="width:147px;">AM9906</td>
			<td></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:264px;">Brilliant III Ultra Fast QPCR mastermix</td>
			<td>Agilent Technologies </td>
			<td style="width:147px;">600880</td>
			<td></td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;">Thermo-Fast 96 Detection plate </td>
			<td style="width:155px;">Thermo Fisher Scientific</td>
			<td style="width:147px;">AB-1100</td>
			<td></td>
			<td></td>
		</tr>
		<tr height="42">
			<td height="42" style="height:42px;width:264px;">Ultra clear qPCR cap strips</td>
			<td style="width:155px;">Thermo Fisher Scientific</td>
			<td style="width:147px;">AB-0866</td>
			<td></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:264px;">Mx3005 QPCR System</td>
			<td style="width:155px;">Agilent Technologies </td>
			<td style="width:147px;">401449</td>
			<td></td>
			<td></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:264px;"> </td>
			<td style="width:155px;"> </td>
			<td style="width:147px;"> </td>
			<td></td>
			<td></td>
		</tr>
		<tr height="21">
			<td colspan="2" height="21" style="height:21px;">* alternative sources are available for most/all products listed</td>
			<td style="width:147px;"> </td>
			<td></td>
			<td></td>
		</tr>
	</tbody>
</table>

investigating the effects of probiotics on pneumococcal colonization using an in vitro adherence assay

Adherence of Streptococcus pneumoniae (the pneumococcus) to the epithelial lining of the nasopharynx can result in colonization and is considered a prerequisite for pneumococcal infections such as pneumonia and otitis media. In vitro adherence assays can be used to study the attachment of pneumococci to epithelial cell monolayers and to investigate potential interventions, such as the use of probiotics, to inhibit pneumococcal&#160;colonization.&#160;The protocol described here is used to investigate the effects of the probiotic Streptococcus salivarius on the adherence of pneumococci to the human epithelial cell line CCL-23 (sometimes referred to as HEp-2 cells). The assay involves three main steps: 1) preparation of epithelial and bacterial cells, 2) addition of bacteria to epithelial cell monolayers, and 3) detection of adherent pneumococci by viable counts (serial dilution and plating) or quantitative real-time PCR (qPCR). This technique is relatively straightforward and does not require specialized equipment other than a tissue culture setup. The assay can be used to test other probiotic species and/or potential inhibitors of pneumococcal colonization and can be easily modified to address other scientific questions regarding pneumococcal adherence and invasion.

Results from a representative experiment in which pneumococci (S. pneumoniae PMP843, a colonizing 19F isolate) were added to CCL-23 cells 1 hr after the addition of S. salivarius, and pneumococcal adherence was quantified by both viable count and lytA qPCR are shown in Table 2. Results were consistent between the two methods for both the absolute number of bacteria (presented as CFU/ml) and the % adherence, normalized to the number of adherent pneumococci in the wells containin...

Watch this Scientific Journal Video about Investigating the Effects of Probiotics on Pneumococcal Colonization Using an In Vitro Adherence Assay at JoVE.com

Investigating the Effects of Probiotics on Pneumococcal Colonization Using an In Vitro Adherence Assay

In vitro adherence assays can be used to study the attachment of Streptococcus pneumoniae to epithelial cell monolayers and to investigate potential interventions such as the use of probiotics for inhibiting pneumococcal colonization.

Investigating the Effects of Probiotics on Pneumococcal Colonization Using an In Vitro Adherence Assay

Adherence of Streptococcus pneumoniae (the pneumococcus) to the epithelial lining of the nasopharynx can result in colonization and is considered a ...

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Immunology and Infection

12.5K vistas.  Murdoch Childrens Research Institute.  En ensayos in vitro de adherencia se pueden utilizar para estudiar la unión de Streptococcus pneumoniae a monocapas de células epiteliales y para investigar las posibles intervenciones, tales como el uso de los probióticos para la inhibición de la colonización neumocócica. 