Characterization of the adherence properties of human Lactobacilli strains to be used as vaginal probiotics

R E S EA RCH L E T T E R

Characterization of the adherence properties of humanLactobacilli strains to be used as vaginal probiotics

Rebeca Martın1,2, Borja Sanchez2,3, Juan Evaristo Suarez1,3 & María C. Urdaci2

1Laboratory of Microbiology, University Institute of Biotechnology, University of Oviedo, Oviedo, Spain; 2UMR 5248, ENITAB, Laboratoire de

Microbiologie et Biochimie Appliquée, Université de Bordeaux, Gradignan, France; and 3Instituto de Productos Lácteos de Asturias, Consejo

Superior de Investigaciones Científicas (IPLA-CSIC), Villaviciosa, Asturias, Spain

Correspondence: Rebeca Martın, INRA,

UMR 1319 MICALIS-Microbiologie de

l'Alimentation au Service de la Santé

humaine, Pôle Ecosystèmes: Interactions des

bactéries commensales et probiotiques avec

l'hôte, Domaine de Vilvert, Bât 440 R-2

78352, Jouy en Josas, Cedex, France. Tel.:

+33 1 34 65 20 98; fax: +33 1 34 65 24 62;

e-mail: [email protected]

Received 4 October 2011; revised 21

December 2011; accepted 21 December

2011. Final version published online 16

January 2012.

DOI: 10.1111/j.1574-6968.2011.02495.x

Editor: Wolfgang Kneifel

Keywords

vaginal Lactobacillus; adhesion; secreted

proteins; surface proteins; mucin; epithelial

cell cultures.

Abstract

In the present work, the adhesion of 43 human lactobacilli isolates to mucin

has been studied. The most adherent strains were selected, and their capacities

to adhere to three epithelial cell lines were studied. All intestinal strains and

one vaginal isolate adhered to HT-29 cells. The latter was the most adherent to

Caco-2 cells, although two of the intestinal isolates were also highly adherent.

Moreover, five of the eight strains strongly adhered to HeLa cells. The binding

of an Actinomyces neuii clinical isolate to HeLa cells was enhanced by two of

the lactobacilli and by their secreted proteins, while those of another two

strains almost abolished it. None of the strains were able to interfere with the

adhesion of Candida albicans to HeLa cells. The components of the extracellu-

lar proteome of all strains were identified by MALDI-TOF/MS. Among them, a

collagen-binding A precursor and aggregation-promoting factor–like proteins

are suggested to participate on adhesion to Caco-2 and HeLa cells, respectively.

In this way, several proteins with LysM domains might explain the ability of

some bacterial supernatants to block A. neuii adhesion to HeLa cell cultures.

Finally, glyceraldehyde 3-phosphate dehydrogenase (GAPDH) could explain the

good adhesion of some strains to mucin.

Introduction

The balance between the different microorganisms inhab-

iting the human vagina is important for the maintenance

of its homeostasis, affecting directly the health status of

the woman. Among the resident microorganisms, the Lac-

tobacillus isolates represent at least 70% of the bacteria

sampled (Redondo-López et al., 1990; Martín et al.,

2008b) being the most dominant L. crispatus, L. jensenii,

and L. gasseri and in less extent L. salivarius, L. vaginalis,

and L. iners (Boyd et al., 2005; Martín et al., 2008a, b).

Because of their relative abundance, lactobacilli have been

proposed as probiotics to be used against the establish-

ment and overgrowth of pathogenic microorganisms in

the vagina. These benefits would be exerted by two differ-

ent mechanisms: (i) competition for attachment sites

on epithelial cells and pathogen co-aggregation and (ii)

production of antimicrobial compounds (Lepargneur &

Rousseau, 2002). The first leads to formation of a biofilm

that prevents the colonization by undesirable microorgan-

isms (Antonio et al., 2005). In addition, some lactobacilli

can co-aggregate with these potential pathogens, such as

Escherichia coli, Candida albicans, and Gardnerella vagi-

nalis, which may help in the clearance of the pathogen

(Boris et al., 1998; Osset et al., 2001). The antimicrobials

are mainly organic acids produced from the fermentation

of sugars, which leads to the typical low pH of the vagina.

This low pH is able to inhibit the growth of most patho-

gens (Boskey et al., 2001).

Probiotics are defined as ‘live microorganisms which

when administered in adequate amounts confer a health

benefit on the host’ (FAO/WHO, 2006). Use of lactoba-

cilli as probiotic agents in the human genitourinary tract

has a long history of safe use, which dates from 1915

(Newman, 1915). Among the physiological traits that are

desirable for potential probiotic lactobacilli, adhesion to

ª 2011 Federation of European Microbiological Societies FEMS Microbiol Lett 328 (2012) 166–173Published by Blackwell Publishing Ltd. All rights reserved

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epithelial surfaces is of paramount importance. It is well

known that, in healthy women, the cervix produces

mucus that is mainly composed of mucin, among other

components (Moghissi et al., 1960) acting as a protective

barrier for the uterus and the vagina (Wang & Lee,

2002). A good adhesion to mucin is thus a desirable char-

acteristic, which may increase the residence time of probi-

otic lactobacilli, as happens with intestinal Lactobacillus

strains (McGrady et al., 1995; Perea Vélez et al., 2007).

The quick turnover of the vaginal mucosa makes adhe-

sion a crucial feature for the establishment and coloniza-

tion of probiotic lactobacilli; thus, it is necessary to

characterize the bacterial adhesion an efficient in vitro

model (Van den Abbeele et al., 2009).

In the present study, the adhesion abilities of 32 vagi-

nal and 11 intestinal Lactobacillus strains to mucin have

been characterized. Among them, eight strains were

selected to characterize their adhesion abilities to Caco-2,HT-29, and HeLa cells, three well-known epithelial cell

models. The interference of the lactobacilli cells and their

secreted proteins on the adhesion of the vaginal patho-

gens C. albicans and Actinomyces neuii to the vaginal cell

line HeLa was determined as well. Finally, secreted and

surface proteins were identified, with some of them being

suggested as molecular elicitors of the interaction between

the lactobacilli and the mucosal surface.

Materials and methods

Bacterial strains, cell lines, and growth

conditions

The Lactobacillus strains used in this study were isolated

from the vagina of fertile women or had an intestinal ori-

gin and were selected because of their good probiotic

properties (Martín et al., 2008a, unpublished data). Acti-

nomyces neuii R1 was isolated from a vaginal swab of a

woman with vulvovaginitis, whereas C. albicans CECT

1392, Lactobacillus rhamnosus GG (ATCC 53103), and

Lactobacillus plantarum 299V (DSM 9843) were obtained

from the Colección Española de Cultivos Tipo, the Ameri-

can Type Culture Collection and the German Collection

of Microorganisms and Cell Cultures, respectively.

Lactobacilli were grown in MRS broth (Difco, Detroit),

whereas C. albicans and A. neuii were grown in BHI

broth (Oxoid, Cambridge, UK) supplemented with 1%(w/v) yeast extract (Difco), 0.1% (w/v) maltose (VWR,

Haasrode, Belgium), 0.1% (w/v) glucose (VWR), and 1%(v/v) defibrinated horse blood (Eurobio, Les Ulis, France)

(supplemented BHI, S-BHI). When appropriated, 1.5%(w/v) agar (Difco) was added to the liquid medium. Acti-

nomyces neuii, C. albicans, and agar cultures of the lacto-

bacilli were incubated in anaerobic jars using the

AnaeroGen Compact system (Oxoid). All the strains were

grown at 37 °C.The Caco-2 (HTB-37) (LGC-Standars, Molsheim, France)

cell line was routinely grown in Eagle's minimal essential

medium (EMEM) (Sigma-Aldrich Chemie GmbH, Buchs,

Switzerland). HeLa (ATCC CCL-2) and HT-29 (HTB-38)(LGC-Standars) cell lines were grown in Dulbecco'smodified Eagle's minimal essential medium (DMEM)

(Sigma-Aldrich). Both culture broths were supplemented

with 10% (w/v) heat-inactivated fetal bovine serum (Gib-

coBRL, Eragny, France) and with penicillin G/streptomycin

(5000 IU mL−1, 5000 μg mL−1) (Sigma-Aldrich). Cultureswere incubated in 25 cm2 tissue culture flasks (Nunc,

Roskilde, Denmark) at 37 °C in a 5% (v/v) CO2 atmosphere

until confluence. For adhesion assays, 2500 cells per well

were seeded in 12-well culture plates (Nunc) and cultivated,

with a daily change of the culture medium until confluence

(Tallon et al., 2007).

Adhesion assays

Adhesion to porcine gastric mucin (Porcine gastric

mucin, type III, Sigma-Aldrich), Caco-2, HT-29, and

HeLa monolayers of the lactobacilli and the pathogenic

bacteria was tested following the procedure described by

Tallon and co-workers (Tallon et al., 2007), using around

108 CFUs (as determined by plate count) for the adhesion

to mucin and 50 bacteria per eukaryotic cell for the adhe-

sion to epithelial cell tests. Overnight bacterial cultures, in

the early stationary phase of growth, and confluent

eukaryotic cell cultures were used in all cases. Assays were

performed at least in triplicate, and the data are expressed

as the mean ± SD.

Protein binding assay

Binding assays were performed using the surface proteins

extracted from 50 mL of culture or secreted proteins

extracted from 20 mL of culture and mucin as coated

matrix on 96-well plates as described before (Sánchezet al., 2009). Proteins were resolved by SDS-PAGE and

then visualized by standard silver staining. Proteins able

to bind mucin were identified by its relative electropho-

retic mobility with respect to the surface proteins profiles.

Interference with pathogen adhesion

The effect of the eight Lactobacillus strains on the adhe-

sion of C. albicans CECT 1392 and A. neuii R1 to HeLa

cells was performed as described earlier, using a probiotic/pathogen ratio of 10 : 1. After incubation with the cell line

monolayers and five PBS washes, aliquots of the cultures

or their dilutions were transferred to plates containing

FEMS Microbiol Lett 328 (2012) 166–173 ª 2011 Federation of European Microbiological SocietiesPublished by Blackwell Publishing Ltd. All rights reserved

Adherence properties of human Lactobacilli strains 167

S-BHI with 20 μg mL−1 penicillin G (selective for C. albi-

cans) or 16 μg mL−1 erythromycin (Sigma-Aldrich) (selec-tive for A. neuii). The susceptibility of all Lactobacillus

strains to both antibiotics was confirmed prior to the

adhesion assays.

To check the effect of extracellular proteins on the

adhesion of the two pathogens to HeLa cells, 250 or

500 μg of crude extracellular protein preparations was

added to each well and incubated at 37 °C for 1 h prior

to the adhesion assays, which were performed using 50

microorganisms per eukaryotic cell, as already described.

At least three independent assays were performed, and

the results were expressed as the mean ± SD.

Statistical analysis

Statistical analysis was performed using GRAPHPAD Prism

Software version 5.00 for Windows (San Diego, CA). The

groups were compared using one-way analysis of variance

(ANOVA) followed by the Student–Newman–Keuls multiple

comparison post hoc analysis. A P-value of < 0.05 was

considered significant.

Results

Adhesion to mucin of the Lactobacillus strains

Adhesion of 43 human lactobacilli, isolated from the gas-

trointestinal tract or from vagina, to mucin was first

characterized (Supporting Information, Table S1). Of the

43 strains tested, 27 showed higher adhesion capabilities

to mucin than L. rhamnosus GG being statistical signifi-

cant for 10 of them (P-value < 0.05). In fact, the best per-

forming strain, L. plantarum Li70, adhered 51 times more

than L. rhamnosus GG. In the rest of the experiments,

only the eight most adherent lactobacilli with different

RAPD profile were selected (Table 1, Data S1). Strain

Lv67 was also selected as a negative control.

Bacterial adhesion to epithelial cell lines

Adhesion was tested using two epithelial cell lines of

intestinal origin (Caco-2 and HT-29) and the vaginal cell

line HeLa (Fig. 1). Lactobacillus casei Li71, L. gasseri Lv19,

and L. plantarum Li68 were the most adherent strains to

HeLa cells. Lactobacillus vaginalis Lv67, L. plantarum

Li68, and L. casei Li71 showed the best adhesion to Caco-2, and finally, L. plantarum Li68, L. plantarum Li69,

L. plantarum Li70, L. casei Li71, and, to a lesser extent,

L. vaginalis Lv67 were the most adherent to HT-29. Allthe adhesion values showed statistical differences (P-value < 0. 05) comparing to each control in all the cell

lines used.

Effect on pathogen adhesion

The effect of the lactobacilli and their secreted proteins

on the adhesion of the vaginal pathogens C. albicans and

A. neuii to HeLa cells was then investigated (Fig. 2). Inhi-

bition values were calculated as adherent bacteria per

HeLa cell. Lactobacillus gasseri Lv19 and L. plantarum

Li70 increased significantly the adhesion of A. neuii R1 to

HeLa cells (P-value < of 0.05 and 0.001, respectively), as

well as their extracellular proteins (P-value < 0.001),

although the proteins of Lv70 do not show statistical dif-

ferences (Fig. 2a and b). Conversely, the proteins secreted

by L. plantarum Li69 and L. salivarius Lv72 abrogated the

adhesion of A. neuii to the same cell line (P-value < 0.

05) (Fig. 2b). Regarding C. albicans, some Lactobacillus

strains slightly enhanced the adhesion of the yeast (no

significant differences) (Fig. 2c), while their secreted pro-

teins did not have any effect (Fig. 2d).

Identification of the Lactobacillus secreted and

surface-associated proteins

Crude preparations of the proteins secreted by the eight

Lactobacillus strains in MRS broth (Fig. 3a) and their sur-

face-associated proteins (Fig. 3b) were resolved by SDS-PAGE. The most intense bands were excised manually

and identified by mass spectrometry (Tables S2 and S3).

Table 1. Adhesion to mucin, classification according to their RAPD

profiles, and identification of the strains at the level species by partial

sequencing of ribosomal DNA gene 16S. Data have been normalized

using the adhesion values of Lactobacillus casei ssp. rhamnosus GG

(ATTC 53103) because of its good adhesion capacities to this

compound (Gueimonde et al., 2004), which was given the arbitrary

value of 1

Strain

RAPD

profile Species

Adhesion

(mean ± SD) Origin

Li81 1a Lactobacillus plantarum 23.32 ± 9.91* Intestinal

Li82 1a Lactobacillus plantarum 3.11 ± 1.61 Intestinal







Li70 1b Lactobacillus plantarum 51.81 ± 32.47* Intestinal

Lv19 2 Lactobacillus gasseri 17.48 ± 8.01* Vaginal

Li68 3 Lactobacillus plantarum 9.65 ± 1.24* Intestinal

Lv72 4 Lactobacillus salivarius 4.49 ± 0.18* Vaginal

Li71 5 Lactobacillus casei 17.44 ± 10.94* Intestinal

Lv57 6 Lactobacillus jensenii 1.01 ± 0.08* Vaginal

Lv67 7 Lactobacillus vaginalis 0.58 ± 0.67 Vaginal

Results are expressed as the mean ± SD of at least three independent

experiments.

*Strains more adherent than LGG (P-value < 0.05).


168 R. Martın et al.

Among the extracellular proteins detected, cell wall hy-

drolases, muramidases, peptidoglycan-binding polypep-

tides, and a precursor of the collagen-binding A protein

were identified. In addition, some moonlighting proteins,

such as glyceraldehyde 3-phosphate dehydrogenase, were

also found. The bacterial lysis of the cultures was negligi-

ble, as can be deduced from the comparison of secreted

protein/total protein profiles obtained by SDS-PAGE(Fig. 3c).

Adhesion of extracellular proteins to mucin

Analysis of the relative electrophoretic mobility of the

proteins recovered after binding experiments suggested

that the surface proteins ABC transporter periplasmic

protein, ornithine carbamoyltransferase, and a high-affin-ity cystine-binding protein bound mucin (Fig. 4a). Also,

the secreted GAPDH of L. plantarum Li69 and Li70 and

that of L. gasseri Lv19 bound mucin, as it did murami-

dase and putative extracellular protein from L. plantarum

Lv69 and Li70 (Fig. 4b).

Discussion

One of the tests considered as crucial by the FAO/WHO

for the in vitro evaluation of potential probiotic candi-

dates is their capacity to adhere to mucin and human

epithelial cells, as well as their antagonism toward patho-

gen establishment (FAO/WHO, 2006). The eight most

adherent Lactobacillus strains were selected, and their

adhesion abilities to three cell lines, their capability of

interfering with the adhesion of two vaginal pathogens to

a model human cell line, and the identification of their

extracellular proteins and their ability to bind mucin were

established.

Presence of typical intestinal lactobacilli, such as L. plan-

tarum, in vaginal environment has been reported previ-

ously and related to the decreased risk of bacterial

vaginosis (Antonio et al., 2005). Besides, the vaginal epi-

thelium is also covered by a protective layer of mucus,

which is mainly composed of mucins as the intestinal one,

although no commercial vaginal mucin is available (Dasari

et al., 2007). In this context, mucins produced in the gas-

trointestinal and vaginal epithelium are very different. In

the gut, MUC2 is mainly produced by goblet cells

(McGuckin et al., 2011), whereas in the vaginal epithe-

lium, MUC1, MUC4, MUC5AC, MUC5B, or MUC6 is

produced, depending on the location (Gipson et al., 1997).

Regarding the adhesion experiments to human cell

lines, the four intestinal isolates presented affinities to

HT-29 cells in the order of the positive control L. planta-

rum 229V. Therefore, this is an especially valuable probi-

otic property that, join to their ability to resist bile salts

and acid (data not shown), might allow the use of Lv67,

Li68, and Li71 in restoration of the vaginal ecosystem

through oral administration.

Fig. 1. Adhesion of the different Lactobacillus strains to HeLa (a),

Caco-2 (b), and HT-29 (c) cells. Results are expressed as the CFU per

eukaryotic cell (mean ± SD) of at least three independent experiments.

Candida albicans CECT1392 was used as positive control of adhesion

to HeLa cells, whereas Lactobacillus plantarum 229V was used with

the same purpose for Caco-2 and HT-29 cells. The adhesion of

Actinomyces neuii R1 to HeLa cells is also represented. Note the change

in the magnitude of the values of the ordinate axis. *P-value < 0.05.



Binding of lactobacilli or their secreted compounds

may either hinder colonization of the epithelium by

potential pathogens, or create a barrier between them and

the mucosal cells, thus excluding direct contact with the

underlying epithelium. The lactobacilli strains were con-

fronted to C. albicans, which is responsible for at least

85% of human candidiasis (Rein, 1997), and A. neuii,

which is the second most frequent microorganism iso-

lated in the Ison and Hay grade II and III vaginal micro-

biota represented by bacterial vaginosis-related organisms

(Verhelst et al., 2005) and has been also associated with

bacterial vaginosis in women with intrauterine devices

(Chatwani & Amin-Hanjani, 1994). Four of the lactoba-

cilli enhanced the adherence of C. albicans and A. neuii

to HeLa cells, which contrasts with previous findings,

where pathogen adhesion inhibition was reported (Boris

et al., 1998; Osset et al., 2001). This fact suggests that this

trait is strain specific. In fact, although the formation of a

ternary complex pathogen–Lactobacillus–epithelial cell

might enhance the antimicrobial effect of the lactic acid

generated by this bacteria (Boris et al., 1997; Coudeyras

et al., 2008), these ternary complexes could also enhance

the pathogen adhesion as has been observed with Lacto-

bacillus acidophilus and the adhesion of C. albicans to the

contraceptive vaginal ring (Chassot et al., 2010).

Adhesion of A. neuii was very responsive to the addi-

tion of the extracellular proteins of the lactobacilli in a

strain-dependent fashion. Five of them enhanced adsorp-

tion of the pathogen, thus reproducing the results obtained

when whole bacterial cells were used. It is worth mention-

ing the extraordinary adhesion increment brought about

by L. gasseri Lv19, which could be due to the secretion of

an aggregation-promoting factor–like protein. In fact, it

has already been described that these factors act as bridges

between pathogen and human cells (Marcotte et al., 2004).

This synergistic effect has also been described for some exo-

polysaccharides produced by several probiotic bacteria,

including L. rhamnosus GG (Ruas-Madiedo et al., 2006).

Interestingly, the extracellular proteins of L. plantarum

Li69 and of L. salivarius Lv72 markedly inhibited the

adhesion of A. neuii to HeLa cells. Among the different

proteins secreted by these strains, several contained LysM

domains, such as two peptidoglycan-binding proteins of

Lv72. The LysM domain has been proposed to be the

attachment site of the autolysin AcmA of Lactococcus lac-

tis to peptidoglycan (Steen et al., 2003). Recently, an

extracellular chitin-binding protein from L. plantarum,

containing this domain, has been shown to attach to the

cell surface and to selective bind N-acetylglucosamine-containing polymers (Sánchez et al., 2010). Notably, the

Lv19 extracellular proteome, which enhanced A. neuii

adhesion, did not include any LysM-bearing polypeptides.

It is thus conceivable that binding of the LysM-bearingproteins to the A. neuii surface might block the ligands

Fig. 2. Adhesion of Actinomyces neuii R1

(a and b) and Candida albicans CECT 1392

(c and d) to HeLa cells in the presence of

lactobacilli (a and c) and their secreted

proteins (b and d). The data are expressed as

the CFU per well (mean ± SD) of at least three

independent experiments. For a better

visualization of the effect of living cells and

extracellular proteins on pathogen adhesion,

values were normalized using the adhesion of

the corresponding pathogen under standard

conditions, which was given the value 1.

**P-value < 0.001; *P-value < 0.05.



that recognize the surface of the HeLa cells, as already

shown for other proteins (Spurbeck & Arvidson, 2010).

This fact points out Lv72 as another good probiotic can-

didate, due also to its moderate ability to bind HeLa cells.

However, other bacterial skills such as hydrogen peroxide,

bacteriocin and acid production, and resistance to antibiot-

ics, low pH, and spermicidal compounds, among other

properties, have to be taken into account to do the correct

selection of a vaginal probiotic (Martín et al., 2008a, b).

Besides, nowadays, there is a tendency to use a combina-

tion of various strains to cover the whole range of charac-

teristics required in a vaginal probiotic.

Surface and secreted protein extracts are important to

detect potential mucin-binding proteins. Among the sur-

face proteins, ornithine carbamoyltransferase (R16) and

amino acid ABC transporter periplasmic protein and

high-affinity cystine-binding protein (both in band R126)

of L. vaginalis Lv67 bound mucin. High-affinity cystine-binding proteins are surface proteins that are frequently

suggested to be putative adhesions. For instance, BspA, a

cystine-binding protein of Lactobacillus fermentum BR11,

has been described as a collagen-binding protein (Hung

et al., 2005).

Among the secreted protein fraction, an extracellular

form of GADPH was able to bind mucin. The presence

of surface-associated GAPDH is well known in a huge

variety of microorganisms (Sánchez et al., 2008). As a

secreted form, GAPDH has been shown to be a plasmin-

ogen- and fibrinogen-binding protein in E. coli (Egea

et al., 2007). Furthermore, Neissera meningitidis GAPDH-deficient mutant showed a significant reduction in adhe-

sion to human epithelial and endothelial cells compared

to the wild-type and complemented mutant (Tunio et al.,

2010). However, care should be taken in the interpreta-

tion of these results, because the only criteria applied for

Fig. 3. Representative protein patterns, obtained after SDS-PAGE of

the secreted (a), surface (c), and total (b) proteomes from the

different Lactobacillus strains. Strain names are shown on the top of

the lanes. MM, molecular mass standards. *Unidentified bands.

Fig. 4. Representative protein patters, obtained after SDS-PAGE of

the secreted (a) or surface (b) proteins able to bind mucin of the

different Lactobacillus strains. Strain names are shown on the top of

the lanes. MM, molecular mass standards; BSA, bovine serum

albumin.



identification have been the comparison between their

electrophoretical mobility with respect to the surface pro-

tein profiles.

In conclusion, the ability to adhere to mucin and to

the epithelial cell cultures seems to be strain specific

although some association with origin has been found for

HT-29 cells. Some of the strains analyzed have good

capacities on the models tested being good candidates to

be used as vaginal probiotics alone or with other lactoba-

cilli. The data presented in this work also suggest that

certain extracellular proteins produced by intestinal and

vaginal lactobacilli could act as potential mediators in the

molecular interaction with both epithelial cells and patho-

gens. Further research is needed to establish the precise

molecular mechanism of action of these proteins using

convenient genetically modified strains.

Acknowledgements

This work was supported by the CICYT grant AGL2010-

15097 and RM2010-00012-00-00 from the Ministry of

Science and Innovation (Spain) and the FEDER Plan.

R.M. was holder of a scholarship from FICYT (Princip-

ado de Asturias), and B.S. is holder of a Juan de la Cierva

postdoctoral contract from the Ministry of Science and

Innovation (Spain).

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Supporting Information

Additional Supporting Information may be found in the

online version of this article:

Data S1. Additional material and methods and results

section.

Table S1. Adhesion of the 43 isolates to mucin.

Table S2. MS and MS/MS data corresponding to the

identification of extracellular proteins produced by the

different Lactobacillus strains.

Table S3. MS and MS/MS data corresponding to the

identification of surface proteins produced by the differ-

ent Lactobacillus strains.

Please note: Wiley-Blackwell is not responsible for the

content or functionality of any supporting materials sup-

plied by the authors. Any queries (other than missing

material) should be directed to the corresponding author

for the article.



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Characterization of the adherence properties of human Lactobacilli strains to be used as vaginal probiotics