Survival of Campylobacter jejuni in biofilms after chlorine treatment

Survival of C. jejuni in biofilms isolated from two chicken houses in Thailand (FBRL-C04, FBRLB05 and FBRL-B06) after chlorine treatment was studied. Biofilm cultures were grown on stainless steel surface in 50% trypticase soy broth for 3 days, subsequently C. jejuni cells were allowed to attach to these biofilms for 4 h at 25ºC. Sodium hypochlorite was used to prepare sanitizing solution with active chlorine of 15 ppm and 25 ppm. Stainless steel coupons containing C. jejuni with and without biofilms were treated with chlorine for 30 sec and neutralized with 0.05% sodium thiosulfate. At both concentrations, C. jejuni were inactivated to lower than 1 log10CFU/cm2 when initial attachment load was approximately 4 log10CFU/cm2. However, C. jejuni in all samples treated with 15 ppm active chlorine were recovered in enrichment media. When treated with the higher concentration of chlorine, 25 ppm, C. jejuni in biofilm of FBRL-C04 (5/9), FBRL-B06 (1/9) and biofilm-free surface (1/9) could also be recovered. This indicates that chlorine treatment at 15 and 25 ppm could not completely inactivate C. jejuni attached to biofilms and biofilm-free surfaces. Biofilm of FBRL-C04 enhanced the survival of C. jejuni after chlorine treatment at 25 ppm although biofilm initial attachment as determined by plate count method was similar to that of other biofilms. Attachment load of viable biofilm cells may not contribute to enhanced survival of C. jejuni in chlorine treatment

Attachment of Campylobacter jejuni on biofilms from two chicken houses in Thailand

The attachment of C. jejuni on four gram negative biofilms (FBRL-C04, FBRL-B05, FBRL-F01 and FBRL-B06) isolated from two chicken houses were studied. It was found that C. jejuni attached to biofilm of FBRL-F01 at the highest rate (4.4 logCFU/cm2) compared (P<0.05) to FBRL-C04 FBRL-B05 and FBRL-B06 (4.0 4.0 and 4.1 logCFU/cm2, respectively). Coaggregation between C. jejuni and biofilm organisms may indicate the ability of organisms to form biofilm together. Percent coaggregation between C. jejuni and biofilm organisms, FBRL-C04 and FBRL-F01 was 39.14% and 33.70%, respectively, higher (P<0.05) than thatwith FBRL-B05 and FBRL-B06 (-3.38% and 12.87%, respectively). Hydrophobicity of planktonic and biofilm cells of C. jejuni and 4 biofilm producers were measured by the microbial adhesion to hydrocarbon (MATH) method using hexadecane. FBRL-B06 showed the highest (P<0.05) hydrophobicity (68.95%) indicating more hydrophobic components on its cell surface. Planktonic cells had lower (P<0.05) hydrophobicity than biofilm cells. However, the degree of hydrophobicity of biofilm cells was not related to attachment of C. jejuni on biofilms

Alteration of extracellular matrix proteins in atrophic periodontal ligament of hypofunctional rat molars

Abstract Objectives The aim of this study was to investigate the effect of mechanical force on possible dynamic changes of the matrix proteins deposition in the PDL upon in vitro mechanical and in vivo occlusal forces in a rat model with hypofunctional conditions. Materials and methods Intermittent compressive force (ICF) and shear force (SF) were applied to human periodontal ligament stem cells (PDLSCs). Protein expression of collagen I and POSTN was analyzed by western blot technique. To establish an in vivo model, rat maxillary molars were extracted to facilitate hypofunction of the periodontal ligament (PDL) tissue of the opposing mandibular molar. The mandibles were collected after 4-, 8-, and 12-weeks post-extraction and used for micro-CT and immunohistochemical analysis. Results ICF and SF increased the synthesis of POSTN by human PDLSCs. Histological changes in the hypofunctional teeth revealed a narrowing of the PDL space, along with a decreased amount of collagen I, POSTN, and laminin in perivascular structures compared to the functional contralateral molars. Conclusion Our results revealed that loss of occlusal force disrupts deposition of some major matrix proteins in the PDL, underscoring the relevance of mechanical forces in maintaining periodontal tissue homeostasis by modulating ECM composition