RESUMEN
Sneathia amnii is an opportunistic pathogen of the female reproductive tract that has been reported to cause infections during pregnancy and in the post-partum period. Infections outside the reproductive tract have rarely been described. We report the case of a spondylitis due to S. amnii in a 72-year old woman, successfully treated after seven weeks of antimicrobial therapy. Growth of this pathogen guided our diagnosis towards a gynecological pathology; we discovered an endometrium adenocarcinoma. This case emphasizes the need for adequate incubation of discal biopsies, using aerobic and anaerobic enrichment broth with prolonged incubation.
Asunto(s)
Antibacterianos/uso terapéutico , Fusobacterias/clasificación , Espondilitis/diagnóstico , Espondilitis/microbiología , Adenocarcinoma , Anciano , ADN Bacteriano , Neoplasias Endometriales , Femenino , Fusobacterias/efectos de los fármacos , Fusobacterias/aislamiento & purificación , Humanos , ARN Ribosómico 16S , Espondilitis/tratamiento farmacológico , Resultado del TratamientoRESUMEN
The outer cell wall of yeast is characterized by high levels of ß-glucans and mannan-oligosaccharides (MOS), which have been linked with beneficial effects on intestinal health and immune status in dogs. In this study, a standardized in vitro simulation of the canine gastrointestinal tract (Simulator of the Canine Intestinal Microbial Ecosystem; SCIME) was used to evaluate the effect of a Saccharomyces cerevisiae-based product, consisting of 27.5% ß-glucans and 22.5% MOS, on the activity (as assessed by measurement of fermentative metabolites) and composition (as assessed by 16S-targeted Illumina sequencing) of canine intestinal microbiota. The S. cerevisiae-based product was tested at three different dosages, i.e., 0.5, 1.0, and 2.0 g/d. A dose-dependent fermentation pattern was observed along the entire length of the colon, as shown by the increased production of the health-related acetate, propionate, and butyrate for the three concentrations tested (0.5, 1.0, and 2.0 g/d). A consistent finding for all three tested concentrations was the increased propionate production (P < 0.05) in the simulated proximal and distal colon. These changes in terms of fermentative metabolites could be linked to specific microbial alterations at the family level, such as the specific stimulation of the propionate-producing families Porphyromonadaceae and Prevotellaceae upon in vitro exposure to the S. cerevisiae-based product. Other consistent changes in community composition upon repeated exposure included the decrease in the Enterobacteriaceae and the Fusobacteriaceae families, which both contain several potentially opportunistic pathogens. Altogether, the generated data support a possible health-promoting role of a product high in ß-glucans and MOS when supplemented to the dogs' diet.
Asunto(s)
Suplementos Dietéticos/análisis , Perros/fisiología , Microbioma Gastrointestinal/efectos de los fármacos , Mananos/farmacología , Oligosacáridos/farmacología , Saccharomyces cerevisiae/química , beta-Glucanos/farmacología , Animales , Pared Celular/química , Dieta/veterinaria , Perros/microbiología , Enterobacteriaceae/efectos de los fármacos , Enterobacteriaceae/crecimiento & desarrollo , Fermentación , Fusobacterias/efectos de los fármacos , Fusobacterias/crecimiento & desarrollo , Tracto Gastrointestinal/metabolismo , Tracto Gastrointestinal/microbiología , Levadura Seca/químicaRESUMEN
Cadmium (Cd) is an environmental pollutant that poses serious health hazards. Due to the increasing contamination of aquatic systems with Cd, the increased accumulation of Cd in fish has become a food safety and public health concern. The present study was conducted to investigate the effects of waterborne Cd exposure on the microbial community composition and diversity in the gut of common carp. Common carp were exposed to three waterborne Cd concentrations (0, 50 and 500⯵gâ¯Cd L-1) for 4 weeks. Our results indicated that Cd exposure profoundly affected the composition of the gut microbiota in the common carp. At the phylum level, Saccharibacteria were detected in only the 0⯵g and 50⯵gâ¯Cd L-1 exposure groups, and the abundance of Fusobacteria decreased with increasing Cd concentration, while the abundance of Firmicutes increased with increasing Cd concentration. At the genus level, Cetobacterium was the dominant group in the gut of the common carp, and the abundance of Cetobacterium decreased after Cd exposure. Notably, the abundance of Akkermansia muciniphila, a probiotic, was found to decrease after Cd exposure, and the proportions of some Cd-resistant bacteria were found to increase following Cd exposure. Our results also demonstrated that Cd exposure decreased the community diversity of the gut microbiota. These results suggest that Cd exposure may impact the gut homeostasis of common carp and further affect the health of the organism.
Asunto(s)
Bacterias/efectos de los fármacos , Cadmio/toxicidad , Carpas , Microbioma Gastrointestinal/efectos de los fármacos , Contaminantes Químicos del Agua/toxicidad , Animales , Biodiversidad , Firmicutes/efectos de los fármacos , Fusobacterias/efectos de los fármacos , Intestinos/microbiología , Verrucomicrobia/efectos de los fármacosRESUMEN
BACKGROUND: Previous studies on the association of enterobiasis and chronic inflammatory diseases have revealed contradictory results. The interaction of Enterobius vermicularis infection in particular with gut microbiota and induced immune responses has never been thoroughly examined. METHODOLOGY/FINDINGS: In order to answer the question of whether exposure to pinworm and mebendazole can shift the intestinal microbial composition and immune responses, we recruited 109 (30 pinworm-negative, 79 pinworm-infected) first and fourth grade primary school children in Taichung, Taiwan, for a gut microbiome study and an intestinal cytokine and SIgA analysis. In the pinworm-infected individuals, fecal samples were collected again at 2 weeks after administration of 100 mg mebendazole. Gut microbiota diversity increased after Enterobius infection, and it peaked after administration of mebendazole. At the phylum level, pinworm infection and mebendazole deworming were associated with a decreased relative abundance of Fusobacteria and an increased proportion of Actinobacteria. At the genus level, the relative abundance of the probiotic Bifidobacterium increased after enterobiasis and mebendazole treatment. The intestinal SIgA level was found to be lower in the pinworm-infected group, and was elevated in half of the mebendazole-treated group. A higher proportion of pre-treatment Salmonella spp. was associated with a non-increase in SIgA after mebendazole deworming treatment. CONCLUSIONS/SIGNIFICANCE: Childhood exposure to pinworm plus mebendazole is associated with increased bacterial diversity, an increased abundance of Actinobacteria including the probiotic Bifidobacterium, and a decreased proportion of Fusobacteria. The gut SIgA level was lower in the pinworm-infected group, and was increased in half of the individuals after mebendazole deworming treatment.
Asunto(s)
Citocinas/inmunología , Enterobiasis/tratamiento farmacológico , Enterobiasis/inmunología , Enterobius/efectos de los fármacos , Microbioma Gastrointestinal/efectos de los fármacos , Mebendazol/uso terapéutico , Animales , Bifidobacterium/efectos de los fármacos , Bifidobacterium/genética , Bifidobacterium/crecimiento & desarrollo , Bifidobacterium/aislamiento & purificación , Niño , Preescolar , Biología Computacional , Citocinas/biosíntesis , Enterobiasis/microbiología , Enterobiasis/parasitología , Enterobius/genética , Enterobius/inmunología , Heces/parasitología , Femenino , Fusobacterias/efectos de los fármacos , Fusobacterias/genética , Fusobacterias/crecimiento & desarrollo , Fusobacterias/aislamiento & purificación , Microbioma Gastrointestinal/genética , Humanos , Inmunidad/efectos de los fármacos , Inmunoglobulina A Secretora/análisis , Inmunoglobulina A Secretora/inmunología , Intestinos/efectos de los fármacos , Intestinos/inmunología , Intestinos/microbiología , Intestinos/parasitología , Masculino , Mebendazol/administración & dosificación , Salmonella/efectos de los fármacos , Salmonella/genética , Salmonella/crecimiento & desarrollo , Salmonella/aislamiento & purificación , Taiwán/epidemiologíaRESUMEN
The numerous species that make up the oral microbiome are now understood to play a key role in establishment and maintenance of oral health. The ability to taxonomically identify community members at the species level is important to elucidating its diversity and association to health and disease. We report the overall ecological effects of using a toothpaste containing enzymes and proteins compared to a control toothpaste on the plaque microbiome. The results reported here demonstrate that a toothpaste containing enzymes and proteins can augment natural salivary defences to promote an overall community shift resulting in an increase in bacteria associated with gum health and a concomitant decrease in those associated with periodontal disease. Statistical analysis shows significant increases in 12 taxa associated with gum health including Neisseria spp. and a significant decrease in 10 taxa associated with periodontal disease including Treponema spp. The results demonstrate that a toothpaste containing enzymes and proteins can significantly shift the ecology of the oral microbiome (at species level) resulting in a community with a stronger association to health.
Asunto(s)
Bacterias/efectos de los fármacos , Placa Dental/microbiología , Enzimas/farmacología , Encía/microbiología , Microbiota/genética , Boca/metabolismo , Pastas de Dientes/farmacología , Adolescente , Adulto , Bacterias/clasificación , Bacterias/genética , Bacterias/aislamiento & purificación , Técnicas de Tipificación Bacteriana , Bacteroides/efectos de los fármacos , Bacteroides/genética , Bacteroides/aislamiento & purificación , ADN Bacteriano/genética , Femenino , Fusobacterias/efectos de los fármacos , Fusobacterias/genética , Fusobacterias/aislamiento & purificación , Secuenciación de Nucleótidos de Alto Rendimiento , Humanos , Masculino , Persona de Mediana Edad , Salud Bucal , Higiene Bucal/métodos , Porphyromonas/efectos de los fármacos , Porphyromonas/genética , Porphyromonas/aislamiento & purificación , Prevotella/efectos de los fármacos , Prevotella/genética , Prevotella/aislamiento & purificación , Selenomonas/efectos de los fármacos , Selenomonas/genética , Selenomonas/aislamiento & purificación , Streptococcus/efectos de los fármacos , Streptococcus/genética , Streptococcus/aislamiento & purificación , Treponema/efectos de los fármacos , Treponema/genética , Treponema/aislamiento & purificaciónRESUMEN
Gender is one of the factors influencing the intestinal microbial composition in mammals, but whether fish also have gender-specific intestinal microbial patterns remains unknown. In this decade, endocrine disrupting chemicals in surface and ground water of many areas and increasing observation of freshwater male fish displaying female sexual characteristics have been reported. Here we identified the difference in intestinal microbiota between male and female zebrafish, and revealed the influence of endocrine disrupting chemicals on zebrafish intestinal microbiota by using high-throughput sequencing. The results indicated that Fusobacteria, Bacteroidetes and Proteobacteria were dominant in the gut of zebrafish and there were no obvious gender-specific intestinal microbial patterns. Two endocrine disrupting chemicals, Estradiol (E2) and Bisphenol A (BPA), were selected to treat male zebrafish for 5 weeks. E2 and BPA increased vitellogenin expression in the liver of male zebrafish and altered the intestinal microbial composition with the abundance of the phylum CKC4 increased significantly. Our results suggested that because of the developmental character and living environment, gender did not influence the assembly of intestinal microbiota in zebrafish as it does in mammals, but exposure extra to endocrine disrupting chemicals disturbed the intestinal microbial composition, which may be related to changes in host physiological metabolism.
Asunto(s)
Bacteroidetes/aislamiento & purificación , Estrógenos/farmacología , Fusobacterias/aislamiento & purificación , Proteobacteria/aislamiento & purificación , Pez Cebra/microbiología , Animales , Bacteroidetes/efectos de los fármacos , Bacteroidetes/genética , Compuestos de Bencidrilo/farmacología , Estradiol/farmacología , Femenino , Fusobacterias/efectos de los fármacos , Fusobacterias/genética , Microbioma Gastrointestinal/efectos de los fármacos , Secuenciación de Nucleótidos de Alto Rendimiento/métodos , Hígado/efectos de los fármacos , Hígado/metabolismo , Masculino , Fenoles/farmacología , Proteobacteria/efectos de los fármacos , Proteobacteria/genética , ARN Bacteriano/análisis , ARN Ribosómico 16S/análisis , Análisis de Secuencia de ADN/métodos , Vitelogeninas/metabolismo , Pez Cebra/metabolismoRESUMEN
Periapical periodontitis usually results from microbial infection, with these microorganisms occasionally migrating to the root canal, which can lead to further, potentially life-threatening, complications. Here, the susceptibility of 27 bacterial strains to various antimicrobial agents was evaluated. These strains comprised 13 species; 16 of the strains were clinical isolates from periapical lesions. Each strain was inoculated onto blood agar plates containing one of the antimicrobial agents. The plates were incubated anaerobically at 37°C for 96 hr and the minimal inhibitory concentrations (MICs) determined. Ten strains required an MIC of 32 µg/ml or greater for amoxicillin, 6 for cefmetazole, and 5 for cefcapene among ß-lactam antibiotics; 8 strains required an MIC of 32 µg/ml or greater for clindamycin, 4 for azithromycin, and 11 for clarithromycin among macrolide antibiotics; 3 strains required an MIC of 32 µg/ml or greater for ciprofloxacin and 2 for ofloxacin among fluoroquinolones. The effect of cefcapene on 5 strains was evaluated after biofilm formation to investigate the relationship between biofilm formation and susceptibility. All strains showed a decrease in susceptibility after biofilm formation. The results revealed that several antimicrobial agents commonly used in a clinical setting, including amoxicillin, cefmetazole, and clindamycin, are potentially effective in the treatment of orofacial odontogenic infections. The development of resistant strains, however, means that this can no longer be guaranteed. In addition, azithromycin, ciprofloxacin, and ofloxacin were more effective than the 3 ß-lactam antibiotics tested. These results suggest that sensitivity testing is needed if odontogenic infections are to be treated safely and effectively.
Asunto(s)
Farmacorresistencia Bacteriana , Periodontitis Periapical/microbiología , Actinomyces/efectos de los fármacos , Amoxicilina/farmacología , Antibacterianos/farmacología , Azitromicina/farmacología , Biopelículas/efectos de los fármacos , Campylobacter/efectos de los fármacos , Cefmetazol/farmacología , Cefalosporinas/farmacología , Ciprofloxacina/farmacología , Claritromicina/farmacología , Clindamicina/farmacología , Fusobacterias/efectos de los fármacos , Haemophilus/efectos de los fármacos , Humanos , Klebsiella/efectos de los fármacos , Pruebas de Sensibilidad Microbiana , Ofloxacino/farmacología , Porphyromonas/efectos de los fármacos , Propionibacterium/efectos de los fármacos , Staphylococcus hominis/efectos de los fármacos , Veillonella/efectos de los fármacosRESUMEN
Solithromycin is a new fluoroketolide. The purpose of the present study was to investigate the effect of orally administered solithromycin on the human oropharyngeal and intestinal microbiota. Thirteen healthy volunteers (median age, 27.3 years) received oral solithromycin at 800 mg on day 1 followed by 400 mg daily on days 2 to 7. Fecal and saliva samples were collected at baseline and on days 2, 5, 7, 9, 14, and 21 for pharmacokinetic and microbiological analyses. Plasma samples were collected predose on days 2, 5, and 7 as proof of exposure, and solithromycin concentration ranges were 21.9 to 258 ng/ml, 18.0 to 386 ng/ml, and 16.9 to 417 ng/ml, respectively. The solithromycin concentrations in feces were 15.8 to 65.4 mg/kg, 24.5 to 82.7 mg/kg, 21.4 to 82.7 mg/kg, 12.1 to 72.4 mg/kg, 0.2 to 25.6 mg/kg, and 0 to 0.5 mg/kg on days 2, 5, 7, 9, 14, and 21, respectively. The numbers of enterobacteria and enterococci decreased and were normalized on day 14. The numbers of lactobacilli and bifidobacteria decreased from day 2 to day 14 and were normalized on day 21. The clostridia decreased on days 2, 7, and 14 and were normalized on day 21. No Clostridium difficile strains or toxins were detected during the study period. The number of Bacteroides strains was not significantly changed. The solithromycin concentrations in saliva were 0 to 1.2 mg/liter, 0 to 0.5 mg/liter, 0 to 0.5 mg/liter, and 0 to 0.1 mg/liter on days 2, 5, 7, and 9, respectively. The numbers of streptococci decreased on day 2 and were normalized on day 5. The numbers of lactobacilli, prevotellae, fusobacteria, and leptotrichiae decreased from day 2 and were normalized on day 21.
Asunto(s)
Antibacterianos/farmacología , Microbioma Gastrointestinal/efectos de los fármacos , Macrólidos/farmacología , Microbiota/efectos de los fármacos , Orofaringe/microbiología , Triazoles/farmacología , Bifidobacterium/efectos de los fármacos , Clostridioides difficile/efectos de los fármacos , Enterococcus/efectos de los fármacos , Heces/microbiología , Femenino , Fusobacterias/efectos de los fármacos , Voluntarios Sanos , Humanos , Lactobacillus/efectos de los fármacos , Leptotrichia/efectos de los fármacos , Masculino , Pruebas de Sensibilidad Microbiana , Prevotella/efectos de los fármacos , Saliva/microbiología , Streptococcus/efectos de los fármacosRESUMEN
BACKGROUND: Dental implants are commonly used today for the treatment of partially and fully edentulous patients. Despite the high success rate they are not resistant to complications and failure due to a variety of problems including peri-implantitis or peri-mucositis due to bacterial biofilm formation on the implant surface. The use of non-surgical and surgical treatment procedure to promote healing in cases with peri-implantitis have limited efficacy. Here we studied the ability of photodynamic therapy to destroy a known bacterial pathogen and the extracellular matrix architecture of biofilm attached to titanium plates and germanium prisms. METHODS: Titanium plates or germanium prisms were incubated for 24h with Fusobacterium nucleatum a fusiform, gram-negative bacterium was used to enable biofilm formation. Photodynamic therapy was carried out by incubating the biofilm samples on each substrata with porfimer sodium. Treatment was carried out using a diode laser at 630nm, 150mW/cm(2) for light doses ranging from 25-100J/cm(2). Evaluation of killing efficacy was done by counting colony forming units compared to controls. Multiple attenuated internal reflection-infrared spectroscopy (MAIR-IR) and SEM were used to analyze the samples pre and post PDT for validation. RESULTS: F. nucleatum was significantly reduced in a dose dependent manner by treatment with PDT. Changes in biofilm components and strength of bioadhesion were examined with MAIR-IR following jet impingement using calibrated water jets. SEM demonstrates significant morphological alterations in the bacteria, consistent with damage associated with exposure to reactive oxygen species. CONCLUSION: The results are indicative that aPDT is a method that can be used to eradicate micro-organisms associated with biofilm in peri-implantitis on relevant substrata. Data shows that the slime layer of the biofilm is removed and that further methods need to be employed to completely remove weakened or destroyed biofilm matrix components. Reactive oxygen species (ROS) mediated oxidative damage results in morphologic changes as a consequence of changes in cell membrane integrity.
Asunto(s)
Biopelículas/efectos de los fármacos , Implantes Dentales/microbiología , Éter de Dihematoporfirina/administración & dosificación , Matriz Extracelular/efectos de los fármacos , Fusobacterias/efectos de los fármacos , Fotoquimioterapia/métodos , Biopelículas/crecimiento & desarrollo , Matriz Extracelular/patología , Matriz Extracelular/efectos de la radiación , Fusobacterias/fisiología , Fusobacterias/efectos de la radiación , Fármacos Fotosensibilizantes , Esterilización/métodosRESUMEN
International trade with ornamental fish is gradually recognized as an important source of a wide range of different antibiotic resistant bacteria. In this study we therefore characterized the prevalence of selected antibiotic resistance genes in the microbiota found in the carriage water of ornamental fish originating from 3 different continents. Real-time PCR quantification showed that the sul1 gene was present in 11 out of 100 bacteria. tet(A) was present in 6 out of 100 bacteria and strA, tet(G), sul2 and aadA were present in 1-2 copies per 100 bacteria. Class I integrons were quite common in carriage water microbiota, however, pyrosequencing showed that only 12 different antibiotic gene cassettes were present in class I integrons. The microbiota characterized by pyrosequencing of the V3/V4 variable region of 16S rRNA genes consisted of Proteobacteria (48%), Bacteroidetes (29.5%), Firmicutes (17.8%), Actinobacteria (2.1%) and Fusobacteria (1.6%). Correlation analysis between antibiotic resistance gene prevalence and microbiota composition verified by bacterial culture showed that major reservoirs of sul1 sul2, tet(A), tet(B) tet(G), cat, cml, bla, strA, aacA, aph and aadA could be found among Alpha-, Beta- and Gammaproteobacteria with representatives of Enterobacteriaceae, Pseudomonadaceae, Rhizobiaceae and Comamonadaceae being those most positively associated with the tested antibiotic resistance genes.
Asunto(s)
Bacterias/efectos de los fármacos , Bacterias/genética , Microbiota/genética , Actinobacteria/efectos de los fármacos , Actinobacteria/genética , Animales , Antibacterianos/farmacología , Bacteroidetes/efectos de los fármacos , Bacteroidetes/genética , Farmacorresistencia Bacteriana Múltiple , Peces , Fusobacterias/efectos de los fármacos , Fusobacterias/genética , Integrones/genética , Microbiota/efectos de los fármacos , Proteobacteria/efectos de los fármacos , Proteobacteria/genética , ARN Ribosómico 16S/genética , Reacción en Cadena en Tiempo Real de la Polimerasa , Microbiología del AguaRESUMEN
The purpose of this study is to formulate in situ implants containing doxycycline hydrochloride and/or secnidazole that could be used in the treatment of periodontitis by direct periodontal intrapocket administration. Biodegradable polymers [poly (lactide) (PLA) and poly (lactide-co-glycolide) (PLGA)], each polymer in two concentrations 25%w/w, 35%w/w were used to formulate the in situ implants. The rheological behavior, in vitro drug release and the antimicrobial activity of the prepared implants were evaluated. Increasing the concentration of each polymer increases the viscosity and decreases the percent of the drugs released after 24 h. PLA implants showed a slower drugs release rate than PLGA implants in which the implants composed of 25% PLGA showed the fastest drugs release. The in vitro drug release and antimicrobial activity results were compared with results of Atridox. Results revealed that the pharmaceutical formulation based on 25% PLGA containing secnidazole and doxycycline hydrochloride has promising activity in treating periodontitis in comparison with Atridox.
Asunto(s)
Implantes Absorbibles , Doxiciclina/administración & dosificación , Ácido Láctico/administración & dosificación , Metronidazol/análogos & derivados , Periodontitis/tratamiento farmacológico , Poliésteres/administración & dosificación , Ácido Poliglicólico/administración & dosificación , Química Farmacéutica , Doxiciclina/química , Portadores de Fármacos/administración & dosificación , Portadores de Fármacos/química , Combinación de Medicamentos , Evaluación Preclínica de Medicamentos/métodos , Implantes de Medicamentos , Farmacorresistencia Bacteriana , Fusobacterias/efectos de los fármacos , Fusobacterias/aislamiento & purificación , Humanos , Ácido Láctico/química , Metronidazol/administración & dosificación , Metronidazol/química , Peptostreptococcus/efectos de los fármacos , Peptostreptococcus/aislamiento & purificación , Periodontitis/microbiología , Poliésteres/química , Ácido Poliglicólico/química , Copolímero de Ácido Poliláctico-Ácido Poliglicólico , Porphyromonas/efectos de los fármacos , Porphyromonas/aislamiento & purificación , Prevotella/efectos de los fármacos , Prevotella/aislamiento & purificación , Streptococcus/efectos de los fármacos , Streptococcus/aislamiento & purificaciónRESUMEN
The aim was to investigate the anti-caries properties of calcium glycerophosphate (CaGP) using an in vitro bacterial flow cell model. Four flow cells, inoculated from a chemostat containing a seven-organism bacterial consortium, were pulsed with sucrose twice daily, to provide an acidic challenge and pH-cycling conditions. Blocks of enamel and dentine were mounted in each flow cell. In a study on the effect of CaGP concentration, CaGP was pulsed into three of the flow cells, at the same time as the sucrose, to give concentrations of 0.10, 0.25 and 0.50%. Water was pulsed into the fourth flow cell with the sucrose. Microradiography revealed a significant dose response of decreasing demineralization as CaGP concentration increased. Reductions at 0.25 and 0.5% were significant when compared to the control. A second study investigated the effect of timing of CaGP pulsing, relative to sucrose, on enamel and dentine demineralization. CaGP (flow cell concentration 0.2%), was pulsed 1 h before, during or 1 h after the sucrose pulse; a water control was employed. In enamel, pulsing CaGP before the sucrose reduced demineralization significantly compared to concurrent pulsing, which in turn gave a significant reduction compared to pulsing after sucrose, which did not reduce demineralization significantly compared to the water control. In dentine, CaGP reduced demineralization significantly only when pulsed before the sucrose. The findings suggest that in vivo, the anti-caries potential of CaGP may be greater if it is applied before a cariogenic challenge.