Medical Hypotheses 84 (2015) 417–420
Contents lists available at ScienceDirect
Medical Hypotheses journal homepage: www.elsevier.com/locate/mehy
Biofilm formation by vaginal Lactobacillus in vivo G. Ventolini ⇑, E. Mitchell, M. Salazar Texas Tech University Health Sciences Center at the Permian Basin, 800 W. 4th Street, Odessa, TX 79763, United States
a r t i c l e
i n f o
Article history: Received 8 May 2014 Accepted 28 December 2014
a b s t r a c t Biofilm formation by nonpathogenic bacteria is responsible for their stable maintenance in vivo ecosystems as it promotes long-term permanence on the host’s vaginal mucosa. Biofilm formation by Lactobacilli has been reported in vitro but not in vivo. We hypothesize the presence of biofilm formation in vivo could be also documented by microscope photographs (MP) of wet mounts obtained from uninfected vaginal samples satisfying rigorous scientific identification criteria. We analyzed 400 MP from our database, and we were able to determine that 12 MP from 6 different patients contained clues of the formation of biofilm by Lactobacilli. The most probable lactobacillus involved is presumed to be Lactobacillus jensenii. The documentation of biofilm formation by vaginal Lactobacilli at fresh wet mount preparation is significant and has several important clinical preventive and therapeutic implications. Ó 2015 Elsevier Ltd. All rights reserved.
Introduction Biofilms are matrix-enclosed bacterial populations that adhere to each other, to surfaces or interfaces [1]. Previously biofilm formation has been reported in vitro by Lactobacilli obtained from uninfected vaginal biopsy samples [2]. Biofilm formation by nonpathogenic bacteria is responsible for their maintenance in stable ecosystems in vivo situations and could be considered beneficial, promoting the colonization and long-term permanence on the host’s vaginal mucosa. Additionally Lactobacilli may exert a defensive role by interfering with pathogenic bacterial growth and/or adhesion [3]. The formation of biofilms by pathogenic bacteria displays unique characteristics and resistance to conventional antibiotic regimens. For example, Swidsinski et al. demonstrated that neither Metronidazole nor Moxifloxacin effectively eradicated the Gardnerella vaginalis biofilm persistent in women with bacterial vaginosis [4]. Machado et al. demonstrated that G. vaginalis had the greatest capacity to adhere to vaginal epithelium even in the presence of Lactobacillus crispatus. This initial adherence led the way for additional colonizers to aid in the formation of biofilms present in bacterial vaginosis [5]. Martın et al. showed that three different vaginal Lactobacillus jensenii strains strongly adhere to a plastic substrate indicating that this property is dependent on strain and environmental factors [6]. Terraf et al. isolated fifteen species of Lactobacillus from vaginal specimens and demonstrated that biofilm formation differed upon
⇑ Corresponding author. Tel.: +1 432 703 5134; fax: +1 432 335 5104. E-mail address: [email protected] (G. Ventolini). http://dx.doi.org/10.1016/j.mehy.2014.12.020 0306-9877/Ó 2015 Elsevier Ltd. All rights reserved.
strain type, strain, culture medium, inoculum concentration, microbial growth and chemical nature of the support [7]. The hypothesis We hypothesize that the presence of biofilm formation in vivo could also be documented, among other possible means, by microscope photographs (MP) of wet mounts obtained from uninfected vaginal samples. The biofilm formation should be observed in fresh wet mount vaginal microscopic samples obtained from healthy asymptomatic women. The biofilm formation should satisfy all of the following rigorous scientific identification criteria: First, visualization of clumping of Lactobacilli bacteria defined by more than 20 Lactobacilli per High Power Magnification (400); Second, Lactobacilli formation of a surrounding substance observed as a strait or circular fold or ridge; and Third, interaction by group of at least 10 Lactobacilli surrounding other bacteria or squamous epithelial cells. All of the selected MP should include the presence of Lactobacilli, and no other bacteria or white blood cells. Hence MP belonging to patients with bacterial vaginosis and/or anaerobic vaginitis must be excluded. Evaluation of the hypothesis The routine protocol at our specialized vulvo-vaginal clinic includes, for patients with recurrent infections, the evaluation of a wet mount microscopy with related photographic documentation. Therefore each patient consents to vaginal sampling for cultures (including Neisseria gonorrhea, Chlamydia trachomatis, Group beta streptococcus, Ureaplasma urealyticum, Mycoplasma hominis,
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G. vaginalis, fungi and HSV) with the evaluation of a wet mount slide fresh preparation. Additionally microscope photographs (MP) are obtained before and after the corresponding diagnosis is made and appropriate medical therapy is completed. Furthermore, another MP is obtained at the time that the test of cure becomes negative. The database was collected from 200 patients with a medical diagnosis of recurrent vulvovaginitis whose bacterial cultures were positive. Those patients were treated until a negative test of cure was obtained. At that time a new MP was obtained. Therefore each patient had a pre-therapy and a post-therapy documented MP. The wet fresh mount slides were prepared using 0.9% normal saline solution. Each MP was shot at 400 HPM using an American Optical 1–10 clinical visual microscope and an OPTIXCAM Summit camera through an adapted optical ocular. The microscope photographs were classified, catalogued and stored in a specific database containing all of the bacterial culture results. From the database, we sought to identify those MP that suggested, based on the rigorous scientific identification criteria, to portray the presence of biofilm formation by Lactobacilli. The following diagnostic rigorous scientific identification criteria were established and utilized to determine the presence of biofilm: First, visualization of clumping of Lactobacilli bacteria defined by more than 20 Lactobacilli per High Power Magnification (400); Second, Lactobacilli formation of a surrounding substance observed as a strait or circular fold or ridge; and Third, interaction by group of at least 10 Lactobacilli surrounding other bacteria or squamous epithelial cells. All of the selected MP included the presence of Lactobacilli, and no other bacteria or white blood cells. Hence MP belonging to patients with bacterial vaginosis and/or anaerobic vaginitis were excluded. A search in Medline, Embase, Google Scholar, Scopus, Index Medicum and Scirus (retrieved 1/31/2014) using the words vagina, Lactobacilli, in vivo, biofilm formation, wet mount, vaginal discharge, recurrent infections, women and their possible combinations did not reveal any publication regarding this subject. It is important to notice that analyzing de-identified pictures of slides was not considered to be human subject research by our Texas Tech University Health Sciences Center Institutional Review Board on June 11, 2013; as a result IRB approval for our study was not required.
Fig. 1. Lactobacilli interaction with squamous epithelial cells (Ureaplasma urealyticum, after negative test of cure culture).
Fig. 2. Biofilm formation by Lactobacilli (Ureaplasma urealyticum, after negative test of cure culture).
Empirical data From our database of 200 patients, we were able to determine that six of them fulfill the rigorous scientific identification criteria for biofilm formation by Lactobacilli. These MP were obtained at the time of the negative test of cure. Patients A and B had a history of symptomatic U. urealyticum positive culture. Figs. 1 and 2 show biofilm formation by Lactobacilli after their negative test of cure. Additionally patients C and D had a history of symptomatic M. hominis positive culture. Figs. 3 and 4 show biofilm formation by Lactobacilli after their negative test of cure. Furthermore patients E and F were ovulating during a natural menstrual cycle while on infertility evaluation. Their ovulation was diagnosed by a Luteal Hormone elevation in the urine. These two patients had a history of symptomatic recurrent bacterial vaginosis by G. vaginalis. Figs. 5 and 6 show biofilm formation by Lactobacillus after their negative test of cure and the presence of clear cervical ovulatory mucus. We were also able to identify eight additional MP from four patients that only fulfill two of the rigorous scientific identification criteria for biofilm formation by Lactobacilli and were therefore excluded. Four microphotographs were from two asymptomatic
Fig. 3. Biofilm formation by Lactobacilli (Mycoplasma hominis, after negative test of cure culture).
G. Ventolini et al. / Medical Hypotheses 84 (2015) 417–420
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and wet mount normal patients with a history of recurrent bacterial vaginosis by G. vaginalis. And four microphotographs belonged to asymptomatic and wet mount normal post-menopausal patients with a history of recurrent anaerobic vaginitis. Consequences of the hypothesis and discussion
Fig. 4. Large clumping of Lactobacilli (Mycoplasma hominis, after negative test of cure culture).
Fig. 5. Biofilm formation by Lactobacilli and presence of clear cervical mucus.
Fig. 6. Biofilm formation by Lactobacilli and presence of clear cervical mucus.
Lactobacilli are believed to promote a vigorous ecosystem by producing lactic acid, hydrogen peroxide, and bacteriocins that have antibacterial properties. They also produce a thick, protective biofilm in vitro probably utilized for protection against pathogen proliferation. Asymptomatic healthy women characteristically show on Gram stains of vaginal fluid smears a predominance of Lactobacilli particularly L. crispatus, L. jensenii, Lactobacillus gassery and Lactobacillus iners [8]. In contrast, women with bacterial vaginosis (BV) have lost many Lactobacillus species with the exception of L. iners. The in vivo formation of biofilm by Lactobacilli in fresh wet mount microscopic vaginal samples obtained from patients with recurrent vulvo-vaginal colonization has not been previously reported, as per our recent search, in the medical literature. According to Srinivasan et al. subjects without BV either had no biofilms with only a few Lactobacilli scattered sporadically or had a loose bacterial biofilm which did not have any particular structure and was mainly composed of Lactobacillus species [8]. Likewise the significant protective role of Lactobacillus biofilm formation in the female reproductive tract is supported by research performed in bacterial vaginosis and sexually transmitted diseases [10]. The most probable lactobacillus involved in the formation of the biofilm observed in our 6 cases is assumed to be L. jensenii. Our assumption is based on a previous report by Terraf et al. which demonstrated that L. jensenii formed biofilm and L. gassery did not form biofilm in any of the assayed conditions that was tested [7]. Specific strains of Lactobacilli, including Lactobacillus reuteri RC14, Lactobacillus rhamnosus GR-1, and L. iners, have been shown to have the ability to displace Gardnerella biofilm formation in vitro. Interestingly, hydrogen peroxide production and pH were not associated with the elimination of biofilms. Other mechanisms of action may include biosurfactants known to be produced by L. reuteri RC-14 and L. rhamnosus GR-1 that may have played a role in displacement, while production of anti-infective bacteriocins and signaling molecules may have affected viability and pathogen growth. However, the strain L. iners AB-1 was able to reduce the viability of G. vaginalis and form a dense biofilm in its place suggesting the potential therapeutic benefit of analyzing biofilm formation of Lactobacilli species in treating disease [12]. The documentation of biofilm formation by vaginal Lactobacilli at fresh wet mount preparation is significant and has several important implications. From a therapeutic perspective, studies have already documented the role of certain biofilm producing Lactobacilli in managing several types of infections. These bacteria, specifically L. rhamnosus and L. reuteri, have been successfully used as adjuvant treatments for patients with bacterial vaginosis [10] and also appear to have a role in preventing urinary tract infections [9]. Novel therapies for urogenital infections are currently being explored which may include the vaginal administration of probiotic bacteria with the capability to form biofilm in vivo; biofilm formation may aid in the restoration of normal vaginal conditions and eradication of pathogenic bacteria present [7]. As such, the prospective development of an in vivo model to study ways to promote growth of the specific biofilm producing strains of Lactobacilli may have a starting point in our recent discovery. The finding of in vivo biofilm formation by Lactobacilli also has added significance because to date, work regarding biofilm producing bacteria has been hampered by the lack of a suitable in vitro model for urogenital infections in general and BV in particular [11].
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We are currently investigating through qPCR technology the Lactobacilli species responsible for the production of the biofilm as well as the matrix composition and the conditions associated with biofilm formation by Lactobacilli. Conflict of interest No conflicts or funding sources. References [1] Costerton JW, Lewandowski Z, Caldwell DE, Korber DR, Lappin-Scott HM. Microbial biofilms. Annu Rev Microbiol 1995;49():711–45. [2] Swidsinski A, Mendling W, Loening-Baucke V, Ladhoff A, Swidsinski S, Hale LP, et al. Adherent biofilms in bacterial vaginosis. Obstet Gynecol 2005;106:1013–23. [3] Lepargneur JP, Rousseau V. Protective role of the Doderleïn flora. J Gynecol Obstet Biol Reprod 2002;31(5):485–94. [4] Swidsinski A, Dörffel Y, Loening-Baucke V, Schilling J, Mendling W. Response of Gardnerella vaginalis biofilm to 5 days of moxifloxacin treatment. FEMS Immunol Med Microbiol 2011;61:41–6.
[5] Machado A, Jefferson K, Cerca N. Interactions between Lactobacillus crispatus and bacterial vaginosis (BV)-associated bacterial species in initial attachment and biofilm formation. Int J Mol Sci 2013;14(6):12004–12. [6] Martın R, Soberon N, Vaneechoutte M, Florez AB, Vazquez F, Suarez JE. Characterization of indigenous vaginal lactobacilli from healthy women as probiotic candidates. Int Microbiol 2008;11:261–6. [7] Terraf MCL, Juárez Tomás MS, Nader-Macías MEF, Silva C. Screening of biofilm formation by beneficial vaginal lactobacilli and influence of culture media components. J Appl Microbiol 2012;113:1517–29. [8] Srinivasan S, Fredricks DN. The human vaginal bacterial biota and bacterial vaginosis. Interdiscip Perspect Infect Dis 2008:1–22. [9] Beerepoot MA, ter Riet G, Nys S, Van Der Wal WM, de Borgie CA, de Reijke TM, et al. Lactobacillus vs antibiotics to prevent urinary tract infections a randomized, double-blind, non-inferiority trial in postmenopausal women. Arch Intern Med 2012;172(9):704–12. [10] Martinez RC, Franceschini SA, Patta MC, Quintana SM, Gomes BC, De Martinis EC, et al. Improved cure of bacterial vaginosis with single dose of Tinidazole (2G), Lactobacillus rhamnosus GR-1 and Lactobacillus rheuteri RC-14: a randomized, double blind, placebo controlled trial. Can J Microbiol 2009;55(2):133–8. [11] Verstraelen H, Swidsinski A. The biofilm in bacterial vaginosis: implications for epidemiology, diagnosis and treatment. Curr Opin Infect Dis 2013;26:86–9. [12] Saunders S, Bocking A, Challis A, Reid G. Effect of Lactobacillus challenge on Gardnerella vaginalis biofilms. Colloids Surf B Biointerfaces 2007;55(2): 138–42.
Contents lists available at ScienceDirect
Medical Hypotheses journal homepage: www.elsevier.com/locate/mehy
Biofilm formation by vaginal Lactobacillus in vivo G. Ventolini ⇑, E. Mitchell, M. Salazar Texas Tech University Health Sciences Center at the Permian Basin, 800 W. 4th Street, Odessa, TX 79763, United States
a r t i c l e
i n f o
Article history: Received 8 May 2014 Accepted 28 December 2014
a b s t r a c t Biofilm formation by nonpathogenic bacteria is responsible for their stable maintenance in vivo ecosystems as it promotes long-term permanence on the host’s vaginal mucosa. Biofilm formation by Lactobacilli has been reported in vitro but not in vivo. We hypothesize the presence of biofilm formation in vivo could be also documented by microscope photographs (MP) of wet mounts obtained from uninfected vaginal samples satisfying rigorous scientific identification criteria. We analyzed 400 MP from our database, and we were able to determine that 12 MP from 6 different patients contained clues of the formation of biofilm by Lactobacilli. The most probable lactobacillus involved is presumed to be Lactobacillus jensenii. The documentation of biofilm formation by vaginal Lactobacilli at fresh wet mount preparation is significant and has several important clinical preventive and therapeutic implications. Ó 2015 Elsevier Ltd. All rights reserved.
Introduction Biofilms are matrix-enclosed bacterial populations that adhere to each other, to surfaces or interfaces [1]. Previously biofilm formation has been reported in vitro by Lactobacilli obtained from uninfected vaginal biopsy samples [2]. Biofilm formation by nonpathogenic bacteria is responsible for their maintenance in stable ecosystems in vivo situations and could be considered beneficial, promoting the colonization and long-term permanence on the host’s vaginal mucosa. Additionally Lactobacilli may exert a defensive role by interfering with pathogenic bacterial growth and/or adhesion [3]. The formation of biofilms by pathogenic bacteria displays unique characteristics and resistance to conventional antibiotic regimens. For example, Swidsinski et al. demonstrated that neither Metronidazole nor Moxifloxacin effectively eradicated the Gardnerella vaginalis biofilm persistent in women with bacterial vaginosis [4]. Machado et al. demonstrated that G. vaginalis had the greatest capacity to adhere to vaginal epithelium even in the presence of Lactobacillus crispatus. This initial adherence led the way for additional colonizers to aid in the formation of biofilms present in bacterial vaginosis [5]. Martın et al. showed that three different vaginal Lactobacillus jensenii strains strongly adhere to a plastic substrate indicating that this property is dependent on strain and environmental factors [6]. Terraf et al. isolated fifteen species of Lactobacillus from vaginal specimens and demonstrated that biofilm formation differed upon
⇑ Corresponding author. Tel.: +1 432 703 5134; fax: +1 432 335 5104. E-mail address: [email protected] (G. Ventolini). http://dx.doi.org/10.1016/j.mehy.2014.12.020 0306-9877/Ó 2015 Elsevier Ltd. All rights reserved.
strain type, strain, culture medium, inoculum concentration, microbial growth and chemical nature of the support [7]. The hypothesis We hypothesize that the presence of biofilm formation in vivo could also be documented, among other possible means, by microscope photographs (MP) of wet mounts obtained from uninfected vaginal samples. The biofilm formation should be observed in fresh wet mount vaginal microscopic samples obtained from healthy asymptomatic women. The biofilm formation should satisfy all of the following rigorous scientific identification criteria: First, visualization of clumping of Lactobacilli bacteria defined by more than 20 Lactobacilli per High Power Magnification (400); Second, Lactobacilli formation of a surrounding substance observed as a strait or circular fold or ridge; and Third, interaction by group of at least 10 Lactobacilli surrounding other bacteria or squamous epithelial cells. All of the selected MP should include the presence of Lactobacilli, and no other bacteria or white blood cells. Hence MP belonging to patients with bacterial vaginosis and/or anaerobic vaginitis must be excluded. Evaluation of the hypothesis The routine protocol at our specialized vulvo-vaginal clinic includes, for patients with recurrent infections, the evaluation of a wet mount microscopy with related photographic documentation. Therefore each patient consents to vaginal sampling for cultures (including Neisseria gonorrhea, Chlamydia trachomatis, Group beta streptococcus, Ureaplasma urealyticum, Mycoplasma hominis,
418
G. Ventolini et al. / Medical Hypotheses 84 (2015) 417–420
G. vaginalis, fungi and HSV) with the evaluation of a wet mount slide fresh preparation. Additionally microscope photographs (MP) are obtained before and after the corresponding diagnosis is made and appropriate medical therapy is completed. Furthermore, another MP is obtained at the time that the test of cure becomes negative. The database was collected from 200 patients with a medical diagnosis of recurrent vulvovaginitis whose bacterial cultures were positive. Those patients were treated until a negative test of cure was obtained. At that time a new MP was obtained. Therefore each patient had a pre-therapy and a post-therapy documented MP. The wet fresh mount slides were prepared using 0.9% normal saline solution. Each MP was shot at 400 HPM using an American Optical 1–10 clinical visual microscope and an OPTIXCAM Summit camera through an adapted optical ocular. The microscope photographs were classified, catalogued and stored in a specific database containing all of the bacterial culture results. From the database, we sought to identify those MP that suggested, based on the rigorous scientific identification criteria, to portray the presence of biofilm formation by Lactobacilli. The following diagnostic rigorous scientific identification criteria were established and utilized to determine the presence of biofilm: First, visualization of clumping of Lactobacilli bacteria defined by more than 20 Lactobacilli per High Power Magnification (400); Second, Lactobacilli formation of a surrounding substance observed as a strait or circular fold or ridge; and Third, interaction by group of at least 10 Lactobacilli surrounding other bacteria or squamous epithelial cells. All of the selected MP included the presence of Lactobacilli, and no other bacteria or white blood cells. Hence MP belonging to patients with bacterial vaginosis and/or anaerobic vaginitis were excluded. A search in Medline, Embase, Google Scholar, Scopus, Index Medicum and Scirus (retrieved 1/31/2014) using the words vagina, Lactobacilli, in vivo, biofilm formation, wet mount, vaginal discharge, recurrent infections, women and their possible combinations did not reveal any publication regarding this subject. It is important to notice that analyzing de-identified pictures of slides was not considered to be human subject research by our Texas Tech University Health Sciences Center Institutional Review Board on June 11, 2013; as a result IRB approval for our study was not required.
Fig. 1. Lactobacilli interaction with squamous epithelial cells (Ureaplasma urealyticum, after negative test of cure culture).
Fig. 2. Biofilm formation by Lactobacilli (Ureaplasma urealyticum, after negative test of cure culture).
Empirical data From our database of 200 patients, we were able to determine that six of them fulfill the rigorous scientific identification criteria for biofilm formation by Lactobacilli. These MP were obtained at the time of the negative test of cure. Patients A and B had a history of symptomatic U. urealyticum positive culture. Figs. 1 and 2 show biofilm formation by Lactobacilli after their negative test of cure. Additionally patients C and D had a history of symptomatic M. hominis positive culture. Figs. 3 and 4 show biofilm formation by Lactobacilli after their negative test of cure. Furthermore patients E and F were ovulating during a natural menstrual cycle while on infertility evaluation. Their ovulation was diagnosed by a Luteal Hormone elevation in the urine. These two patients had a history of symptomatic recurrent bacterial vaginosis by G. vaginalis. Figs. 5 and 6 show biofilm formation by Lactobacillus after their negative test of cure and the presence of clear cervical ovulatory mucus. We were also able to identify eight additional MP from four patients that only fulfill two of the rigorous scientific identification criteria for biofilm formation by Lactobacilli and were therefore excluded. Four microphotographs were from two asymptomatic
Fig. 3. Biofilm formation by Lactobacilli (Mycoplasma hominis, after negative test of cure culture).
G. Ventolini et al. / Medical Hypotheses 84 (2015) 417–420
419
and wet mount normal patients with a history of recurrent bacterial vaginosis by G. vaginalis. And four microphotographs belonged to asymptomatic and wet mount normal post-menopausal patients with a history of recurrent anaerobic vaginitis. Consequences of the hypothesis and discussion
Fig. 4. Large clumping of Lactobacilli (Mycoplasma hominis, after negative test of cure culture).
Fig. 5. Biofilm formation by Lactobacilli and presence of clear cervical mucus.
Fig. 6. Biofilm formation by Lactobacilli and presence of clear cervical mucus.
Lactobacilli are believed to promote a vigorous ecosystem by producing lactic acid, hydrogen peroxide, and bacteriocins that have antibacterial properties. They also produce a thick, protective biofilm in vitro probably utilized for protection against pathogen proliferation. Asymptomatic healthy women characteristically show on Gram stains of vaginal fluid smears a predominance of Lactobacilli particularly L. crispatus, L. jensenii, Lactobacillus gassery and Lactobacillus iners [8]. In contrast, women with bacterial vaginosis (BV) have lost many Lactobacillus species with the exception of L. iners. The in vivo formation of biofilm by Lactobacilli in fresh wet mount microscopic vaginal samples obtained from patients with recurrent vulvo-vaginal colonization has not been previously reported, as per our recent search, in the medical literature. According to Srinivasan et al. subjects without BV either had no biofilms with only a few Lactobacilli scattered sporadically or had a loose bacterial biofilm which did not have any particular structure and was mainly composed of Lactobacillus species [8]. Likewise the significant protective role of Lactobacillus biofilm formation in the female reproductive tract is supported by research performed in bacterial vaginosis and sexually transmitted diseases [10]. The most probable lactobacillus involved in the formation of the biofilm observed in our 6 cases is assumed to be L. jensenii. Our assumption is based on a previous report by Terraf et al. which demonstrated that L. jensenii formed biofilm and L. gassery did not form biofilm in any of the assayed conditions that was tested [7]. Specific strains of Lactobacilli, including Lactobacillus reuteri RC14, Lactobacillus rhamnosus GR-1, and L. iners, have been shown to have the ability to displace Gardnerella biofilm formation in vitro. Interestingly, hydrogen peroxide production and pH were not associated with the elimination of biofilms. Other mechanisms of action may include biosurfactants known to be produced by L. reuteri RC-14 and L. rhamnosus GR-1 that may have played a role in displacement, while production of anti-infective bacteriocins and signaling molecules may have affected viability and pathogen growth. However, the strain L. iners AB-1 was able to reduce the viability of G. vaginalis and form a dense biofilm in its place suggesting the potential therapeutic benefit of analyzing biofilm formation of Lactobacilli species in treating disease [12]. The documentation of biofilm formation by vaginal Lactobacilli at fresh wet mount preparation is significant and has several important implications. From a therapeutic perspective, studies have already documented the role of certain biofilm producing Lactobacilli in managing several types of infections. These bacteria, specifically L. rhamnosus and L. reuteri, have been successfully used as adjuvant treatments for patients with bacterial vaginosis [10] and also appear to have a role in preventing urinary tract infections [9]. Novel therapies for urogenital infections are currently being explored which may include the vaginal administration of probiotic bacteria with the capability to form biofilm in vivo; biofilm formation may aid in the restoration of normal vaginal conditions and eradication of pathogenic bacteria present [7]. As such, the prospective development of an in vivo model to study ways to promote growth of the specific biofilm producing strains of Lactobacilli may have a starting point in our recent discovery. The finding of in vivo biofilm formation by Lactobacilli also has added significance because to date, work regarding biofilm producing bacteria has been hampered by the lack of a suitable in vitro model for urogenital infections in general and BV in particular [11].
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G. Ventolini et al. / Medical Hypotheses 84 (2015) 417–420
We are currently investigating through qPCR technology the Lactobacilli species responsible for the production of the biofilm as well as the matrix composition and the conditions associated with biofilm formation by Lactobacilli. Conflict of interest No conflicts or funding sources. References [1] Costerton JW, Lewandowski Z, Caldwell DE, Korber DR, Lappin-Scott HM. Microbial biofilms. Annu Rev Microbiol 1995;49():711–45. [2] Swidsinski A, Mendling W, Loening-Baucke V, Ladhoff A, Swidsinski S, Hale LP, et al. Adherent biofilms in bacterial vaginosis. Obstet Gynecol 2005;106:1013–23. [3] Lepargneur JP, Rousseau V. Protective role of the Doderleïn flora. J Gynecol Obstet Biol Reprod 2002;31(5):485–94. [4] Swidsinski A, Dörffel Y, Loening-Baucke V, Schilling J, Mendling W. Response of Gardnerella vaginalis biofilm to 5 days of moxifloxacin treatment. FEMS Immunol Med Microbiol 2011;61:41–6.
[5] Machado A, Jefferson K, Cerca N. Interactions between Lactobacillus crispatus and bacterial vaginosis (BV)-associated bacterial species in initial attachment and biofilm formation. Int J Mol Sci 2013;14(6):12004–12. [6] Martın R, Soberon N, Vaneechoutte M, Florez AB, Vazquez F, Suarez JE. Characterization of indigenous vaginal lactobacilli from healthy women as probiotic candidates. Int Microbiol 2008;11:261–6. [7] Terraf MCL, Juárez Tomás MS, Nader-Macías MEF, Silva C. Screening of biofilm formation by beneficial vaginal lactobacilli and influence of culture media components. J Appl Microbiol 2012;113:1517–29. [8] Srinivasan S, Fredricks DN. The human vaginal bacterial biota and bacterial vaginosis. Interdiscip Perspect Infect Dis 2008:1–22. [9] Beerepoot MA, ter Riet G, Nys S, Van Der Wal WM, de Borgie CA, de Reijke TM, et al. Lactobacillus vs antibiotics to prevent urinary tract infections a randomized, double-blind, non-inferiority trial in postmenopausal women. Arch Intern Med 2012;172(9):704–12. [10] Martinez RC, Franceschini SA, Patta MC, Quintana SM, Gomes BC, De Martinis EC, et al. Improved cure of bacterial vaginosis with single dose of Tinidazole (2G), Lactobacillus rhamnosus GR-1 and Lactobacillus rheuteri RC-14: a randomized, double blind, placebo controlled trial. Can J Microbiol 2009;55(2):133–8. [11] Verstraelen H, Swidsinski A. The biofilm in bacterial vaginosis: implications for epidemiology, diagnosis and treatment. Curr Opin Infect Dis 2013;26:86–9. [12] Saunders S, Bocking A, Challis A, Reid G. Effect of Lactobacillus challenge on Gardnerella vaginalis biofilms. Colloids Surf B Biointerfaces 2007;55(2): 138–42.
