Recombinant lactococcal-based oral vaccine for protection against Streptococcus agalactiae infections in tilapia (Oreochromis niloticus).

Streptococcosis outbreaks caused by Streptococcus agalactiae infection in tilapia aquaculture have been consistently reported and associated with high mortality and morbidity leading to significant economic losses. Existing vaccine candidates against Streptococcus spp. are designed for intraperitoneal injections that are not practical and labor-intensive which have prompted farmers to protect aquatic animals with antibiotics, thus encouraging the emergence of multidrug resistant bacteria. In this study, a live recombinant L. lactis vaccine expressing a 1403 bp surface immunogenic protein (SIP) and a 1100 bp truncated SIP (tSIP) gene was developed and evaluated against S. agalactiae infection in tilapia. Both SIP and tSIP sequences were cloned and transformed into L. lactis. The recombinant L.lactis vaccine was orally administered to juvenile tilapia for a month. Detection of SIP-specific serum IgM in vaccinated groups compared to control groups indicated that recombinant proteins expressed from L. lactis could elicit immunogenic reactions in tilapia. Fish immunized with the tSIP vaccine also showed the highest level of protection compared to other test groups, and the mortality rate was significantly reduced compared to both control groups. The relative percentage of survival (RPS) against S. agalactiae for both SIP and tSIP-vaccinated groups was 50 % and 89 %, respectively, at 14 days post-challenge. Significant up-regulation of IgM, IL-1ß, IL-10, TNF-α and IFN-γ were observed at day 34 between the vaccinated and control groups. These results indicated that the recombinant lactococcal tSIP vaccine can elicit both cell-mediated and humoral responses and is recommended as a potential oral vaccine against S. agalactiae infection. Future work will include further in vivo challenge assessments of this vaccine candidate fused with adjuvants to boost immunogenicity levels in tilapia.

The oral health landscape in Singapore: A commentary on key features, challenges and future policies.

Over the last decade, Singapore has grappled with substantial healthcare challenges, chiefly a bourgeoning aging population and a mounting burden of chronic diseases. The oral health landscape has also changed, with the Ministry of Health placing a greater focus on a life-course approach supported by policies that facilitate Singaporeans to receive dental care appropriately and affordably. A pivotal oral health policy is the National Dental Strategy, a comprehensive framework governing dental services in the public sector. This strategy encompasses aspects such as financing, workforce management, and capacity considerations. To facilitate affordability and accessibility to dental services in the public sector, the government extends subsidies to reduce out-of-pocket costs. Those attending private dental clinics also benefit from the Community Health Assist Scheme, introduced in 2012, which alleviates treatment costs for enrolled Singaporeans. Furthermore, additional age-banded subsidies have been introduced for older Singaporeans born before 1960, enhancing financial support when accessing dental services in both private and public sectors. In 2019, a national adult oral health survey was commissioned to gauge the oral health status of Singaporeans aged 21 and above. The findings reported 34.8% having untreated dental caries, and 15.7% and 41.2% experiencing moderate and severe periodontitis, respectively. While over half (53.9%) of respondents visited the dentist at least annually, about 60% of eligible individuals did not utilize their government dental subsidies. In response, the Ministry of Health is committed to strengthening oral disease prevention, integrating oral health into general healthcare services, expanding dental financing schemes to enhance service utilization, improving the quality and transparency of dental care, and leveraging advancements in tele-dentistry and other modes of dental services. It is imperative to adapt Singapore's oral health policies and service delivery models to meet the evolving needs of the population and ensure a sustainable, equitable and resilient oral healthcare system.

Three-dimensional analysis of the interchangeability of a semiadjustable articulator system in service over time.

STATEMENT OF PROBLEM: Some contemporary articulator systems claim to be highly precise in their interchangeability, with tolerances below 10 µm in vertical error; however, the claims have not been independently verified. PURPOSE: The purpose of this study was to investigate the interchangeability of calibrated semiadjustable articulators in service over time. MATERIAL AND METHODS: A calibrated mounting articulator served as the master articulator, while the test groups were used articulators with a minimum of 1-year use by predoctoral dental students (n=10); used articulators with a minimum of 1-year use by prosthodontic residents (n=10); and new articulators (n=10). One set of mounted maxillary and mandibular master models was positioned in the master and test articulators. High-precision reference markers on the master models were used to determine interarch 3D distance distortions (dRR, dRC, and dRL), interocclusal 3D distance distortion (dRM), interocclusal 2D distance distortions (dxM, dyM, and dzM), and interocclusal angular distortion (dθM) relative to the master articulator. All measurements were conducted three times using a coordinate measuring machine and then averaged to derive the final data set. RESULTS: For interarch 3D distance distortion, the mean dRR ranged from 4.6 ±21.6 µm for new articulators to 56.3 ±47.6 µm for articulators used by prosthodontic residents; mean dRC ranged from 65 ±48.6 µm for new articulators to 119.0 ±58.8 µm for articulators used by prosthodontic residents; and mean dRL ranged from 12.7 ±39.7 µm for articulators used by prosthodontic residents to 62.8 ±75.2 µm for new articulators. For interocclusal 3D distance distortion, the mean dRM ranged from 21.5 ±49.8 µm for new articulators to 68.6 ±64.9 µm for articulators used by predoctoral dental students. For the 2D distance distortions, the mean dxM ranged from -17.9 ±43.4 µm for articulators used by predoctoral dental students to -61.9 ±48.3 µm for articulators used by prosthodontic residents; mean dyM ranged from 18.1 ±59.4 µm for new articulators to 69.3 ±115.1 µm for articulators used by prosthodontic residents; and mean dzM ranged from 29.5 ±20.2 µm for new articulators to 70.1 ±37.8 µm for articulators used by prosthodontic residents. Mean dθM ranged from -0.018 ±0.289 degree for new articulators to 0.141 ±0.267 degree for articulators used by prosthodontic residents. One-way ANOVA by articulator type revealed statistically significant differences among the test groups for dRR (P=.007) and dzM (P=.011) only, where articulators used by prosthodontic residents fared significantly poorer than the other test groups. CONCLUSIONS: The new and used articulators tested did not fulfill the manufacturer's claim of accuracy of up to 10 µm in the vertical dimension. Up to 1 year of time in service, none of the investigated test groups fulfilled the criterion for articulator interchangeability, even if the more lenient threshold of 166 µm were accepted.

Endolysins against Streptococci as an antibiotic alternative.

Multi-drug resistance has called for a race to uncover alternatives to existing antibiotics. Phage therapy is one of the explored alternatives, including the use of endolysins, which are phage-encoded peptidoglycan hydrolases responsible for bacterial lysis. Endolysins have been extensively researched in different fields, including medicine, food, and agricultural applications. While the target specificity of various endolysins varies greatly between species, this current review focuses specifically on streptococcal endolysins. Streptococcus spp. causes numerous infections, from the common strep throat to much more serious life-threatening infections such as pneumonia and meningitis. It is reported as a major crisis in various industries, causing systemic infections associated with high mortality and morbidity, as well as economic losses, especially in the agricultural industry. This review highlights the types of catalytic and cell wall-binding domains found in streptococcal endolysins and gives a comprehensive account of the lytic ability of both native and engineered streptococcal endolysins studied thus far, as well as its potential application across different industries. Finally, it gives an overview of the advantages and limitations of these enzyme-based antibiotics, which has caused the term enzybiotics to be conferred to it.

Three-dimensional positional accuracy of intraoral and laboratory implant scan bodies.

STATEMENT OF PROBLEM: In the implant digital workflow, scan bodies provide the 3D position of digital implants in the virtual dental arch. However, limited evidence is available on scan body accuracy, selection, and usage. PURPOSE: The purpose of this in vitro study was to evaluate the 3D positional accuracy of 4 intraoral and 6 laboratory scan body systems to the implants and laboratory replicas of an implant system under various torque magnitudes. MATERIAL AND METHODS: Ten test groups comprising 4 intraoral (I): Medentika L-Series (MS), Straumann CARES Mono (SM), Core 3D (CO), Straumann RC (SS); and 6 laboratory (L): Nobel Procera Pos Locator (NP), Sirona InPost (SR), Amann Girrbach (AG), Straumann CARES Mono (SM), Core 3D (CO), Straumann RC (SS) scan bodies were derived from 7 scan body systems. Of these, 3 systems (SM, CO, SS) are used for both intraoral and laboratory applications. The scan bodies were tested on Straumann Bone Level Regular CrossFit implants or laboratory replicas. Eight test groups allowed for the variation of torque application (5, 10, and 15 Ncm), while 2 test groups (NP, SR) were hand positioned only. Prefabricated metal abutments (ME) for both implants and laboratory replicas served as controls. A coordinate measuring machine measured four 3D positional accuracy variables: vertical linear distortion (dz), 2D tolerance displacement (dr), global linear distortion (dR), and scan body height discrepancy (ΔH) (n=10). The data were analyzed with 2-way analysis of variance tests and post hoc analysis with Tukey tests (α=.05). RESULTS: For both intraoral and laboratory test groups, 2-way ANOVA found that the system had a significant effect on all distortion variables (P<.001), while torque magnitude had a significant effect only on dz and ΔH (P<.001). Overall, mean dz ranged from 5 ±12 µm for L-AG at 15 Ncm to 23 ±14 µm for L-AG at 5 Ncm. Mean dr ranged from 5 ±4 µm for I-SM at 15 Ncm to 73 ±41 µm for L-SS at 10 Ncm, and mean dR ranged from 11 ±6 µm for I-SM at 10 Ncm to 74 ±41 µm for L-SS at 10 Ncm. Mean ΔH ranged from -5 ±10 µm for I-SM at 15 Ncm to 23 ±14 µm for L-AG at 5 Ncm. Among intraoral test groups, for dz and ΔH, all the test groups except for I-SM at 15 Ncm and I-MS at 10 and 15 Ncm were significantly more positive than the control (P<.001). For dr, I-SS at 5, 10, and 15 Ncm was significantly different from the control (P<.001). For dR, only I-SS at 5 Ncm was significantly different from the control (P<.001). Among laboratory test groups, for dz and ΔH, L-AG at 5 Ncm and L-CO at 15 Ncm were significantly more positive than the control (P<.001). For dr, L-SS at 10 and 15 Ncm were significantly different from the control (P<.001). For dR, only L-SS at 10 Ncm was significantly different from the control (P<.001). Intraoral and laboratory systems show comparable 3D positional accuracy. CONCLUSIONS: Overall, I-SS and L-SS were the least accurate. The system tested had a significant effect on 3D positional accuracy, while torque magnitude had no consistent effect across all systems.

K-Ras Peptide Mimotope Induces Antigen Specific Th1 and B-Cell Immune Responses against G12A-Mutated K-Ras Antigen in Balb/c Mice.

KRAS G12A somatic point mutation in adenocarcinomas is categorized clinically as ineligibility criteria for anti-epidermal growth factor receptor (EGFR) monoclonal antibody therapies. In this study, a modified G12A-K-ras epitope (139A) with sequence-specific modifications to improve immunogenicity was developed as a potential vaccine against G12A-mutant KRAS cancers. Additionally, coupling of the 139A epitope with a tetanus toxoid (TTD) universal T-cell epitope to improve antigenicity was also reported. To facilitate convenient oral administration, Lactococcus lactis, which possesses innate immunomodulatory properties, was chosen as a live gastrointestinal delivery vehicle. Recombinant L. lactis strains secreting a G12A mutated K-ras control and 139A with and without TTD fusion were generated for comparative immunogenicity assessment. BALB/c mice were immunized orally, and high survivability of L. lactis passage through the gastrointestinal tract was observed. Elevations in B-cell count with a concomitant titre of antigen-specific IgG and interferon-γ secreting T-cells were observed in the 139A treated mice group. Interestingly, an even higher antigen-specific IgA response and interferon-γ secreting T-cell counts were observed in 139A-TTD mice group upon re-stimulation with the G12A mutated K-ras antigen. Collectively, these results indicated that an antigen-specific immune response was successfully stimulated by 139A-TTD vaccine, and a TTD fusion was successful in further enhancing the immune responses.

Three-Dimensional Accuracy of Digital Static Interocclusal Registration by Three Intraoral Scanner Systems.

PURPOSE: Prior studies have defined the accuracy of intraoral scanner (IOS) systems but the accuracy of the digital static interocclusal registration function of these systems has not been reported. This study compared the three-dimensional (3D) accuracy of the digital static interocclusal registration of 3 IOS systems using the buccal bite scan function. MATERIALS AND METHODS: Three IOS systems compared were 3MTM True Definition Scanner (TDS), TRIOS Color (TRC), and CEREC AC with CEREC Omnicam (CER). Using each scanner, 7 scans (n = 7) of the mounted and articulated SLA master models were obtained. The measurement targets (SiN reference spheres and implant abutment analogs) were in the opposing models at the right (R), central (C), and left (L) regions; abutments #26 and #36, respectively. A coordinate measuring machine with metrology software compared the physical and virtual targets to derive the global 3D linear distortion between the centroids of the respective target reference spheres and abutment analogs (dRR , dRC , dRL , and dRM ) and 2D distances between the pierce points of the abutment analogs (dXM , dYM , dZM ), with 3 measurement repetitions for each scan. RESULTS: Mean 3D distortion ranged from -471.9 to 31.7 µm for dRR , -579.0 to -87.0 µm for dRC , -381.5 to 69.4 µm for dRL , and -184.9 to -23.1 µm for dRM . Mean 2D distortion ranged from -225.9 to 0.8 µm for dXM , -130.6 to -126.1 µm for dYM , and -34.3 to 26.3 µm for dZM . Significant differences were found for interarch distortions across the three systems. For dRR and dRL , all three test groups were significantly different, whereas for dRC , the TDS was significantly different from the TRC and CER. For 2D distortion, significant differences were found for dXM only. CONCLUSIONS: Interarch and global interocclusal distortions for the three IOS systems were significantly different. TRC performed overall the best and TDS was the worst. The interarch (dRR , dRC , dRL ) and interocclusal (dXM ) distortions observed will affect the magnitude of occlusal contacts of restorations clinically. The final restoration may be either hyperoccluded or infraoccluded, requiring compensations during the CAD design stage or clinical adjustments at issue.