In Vitro Invasion and Survival of Porphyromonas gingivalis in Gingival Fibroblasts; Role of the Capsule
- 608 Downloads
Porphyromonas gingivalis is a Gram-negative, anaerobic bacterium involved in periodontitis and peri-implantitis that can invade and survive inside host cells in vitro. P. gingivalis can invade human gingival fibroblasts (GF), but no data are available about the role of P. gingivalis’ capsule in GF invasion. In the current study, we aimed to determine the ability of three strains of P. gingivalis (encapsulated wild type W83, non-encapsulated HG91 and the non-encapsulated insertional isogenic knockout mutant of W83, ΔEpsC) to invade GF and the ability of internalized P. gingivalis to survive in vitro antibiotic treatment. The ability of P. gingivalis strains to invade GF was tested using an antibiotic protection assay at multiplicity of infection (MOI) 100 and 1000. The survival of internalized P. gingivalis cells was further analyzed by subsequent in vitro treatment with either metronidazole or amoxicillin alone or a combination of metronidazole and amoxicillin and anaerobic culture viability counts. All strains of P. gingivalis used in this study were able to invade GFs. The non-encapsulated mutant of W83 (ΔEpsC mutant) was significantly more invasive than the wild type W83 at MOI 100 (p value 0.025) and MOI 1000 (p value 0.038). Furthermore, internalized P. gingivalis was able to resist in vitro antibiotic treatment. As demonstrated by the differences in invasion efficiencies of P. gingivalis strain W83 and its isogenic mutant ΔEpsC, the capsule of P. gingivalis makes it less efficient in invading gingival fibroblasts. Moreover, internalized P. gingivalis can survive antibiotic treatment in vitro.
KeywordsPeriodontitis Mechanism of antibiotic resistance Internalization Capsule
We thank the “Higher education commission of Pakistan” for supporting this study financially. We thank Dr. Nina Scheres for her valuable technical support and Dr. Jorg Brunner for providing the ΔEpsC isogenic mutant of P. gingivalis W83.
- Colombo AV, da Silva CM, Haffajee A, Colombo AP (2007) Identification of intracellular oral species within human crevicular epithelial cells from subjects with chronic periodontitis by fluorescence in situ hybridization. J Periodontal Res 42(3):236–243. doi: 10.1111/j.1600-0765.2006.00938.x PubMedCrossRefGoogle Scholar
- Hecht DW, Citron DM, Cox M, Jacobus N, Jenkins SG, Onderdonk A, Roe-Carpenter D, Rosenblatt JE, Wexler HM (2007) Methods for antimicrobial susceptibility testing of anaerobic bacteria; approved standard-seventh edition. Clinical and Laboratory Standards Institute (CLSI). http://www.clsi.org/source/orders/free/m11a7.pdf. Accessed 10 Jan 2012
- Yu L, Liu H, E L, Wu X, Wang D (2009) Uptake of metronidazole by human gingival fibroblasts. J Periodontol 80(6):993–998Google Scholar
- Mombelli A, Feloutzis A, Bragger U, Lang NP (2001) Treatment of peri-implantitis by local delivery of tetracycline. Clinical, microbiological and radiological results. Clin Oral Implants Res 12(4):287–294. pii:clr120401Google Scholar
- Schentag JJ, Swanson DJ, Smith IL (1985) Dual individualization: antibiotic dosage calculation from the integration of in vitro pharmacodynamics and in vivo pharmacokinetics. J Antimicrob Chemother 15(Suppl A):47–57Google Scholar
- Singh A, Wyant T, Anaya-Bergman C, Aduse-Opoku J, Brunner J, Laine ML, Curtis MA, Lewis JP (2011) The capsule of Porphyromonas gingivalis leads to a reduction in the host inflammatory response, evasion of phagocytosis, and increase in virulence. Infect Immun 79(11):4533–4542. doi: 10.1128/IAI.05016-11 PubMedCrossRefGoogle Scholar
- St Geme JW, 3rd, Falkow S (1992) Capsule loss by Haemophilus influenzae type b results in enhanced adherence to and entry into human cells. J Infect Dis 165(Suppl 1):S117–118Google Scholar
- Vernal R, Leon R, Silva A, van Winkelhoff AJ, Garcia-Sanz JA, Sanz M (2009) Differential cytokine expression by human dendritic cells in response to different Porphyromonas gingivalis capsular serotypes. J Clin Periodontol 36(10):823–829. doi: 10.1111/j.1600-051X.2009.01462.x PubMedCrossRefGoogle Scholar