Comparison between Two Assessment Tests for Oral Hygiene: Adenosine Triphosphate + Adenosine Monophosphate Swab Test and Bacteria Number Counting by Dielectrophoretic Impedance Measurement

A Comprehensive Analysis of ATP Tests: Practical Use and Recent Progress in the Total Adenylate Test for the Effective Monitoring of Hygiene

ABSTRACT

Rapid hygiene monitoring tests based on the presence of ATP have been widely used in the food industry to ensure that adequate cleanliness is maintained. In this study, the practical applications and limitations of these tests and recent technological progress for facilitating more accurate control were evaluated. The presence of ATP on a surface indicates improper cleaning and the presence of contaminants, including organic debris and bacteria. Food residues are indicators of insufficient cleaning and are direct hazards because they may provide safe harbors for bacteria, provide sources of nutrients for bacterial growth, interfere with the antimicrobial activity of disinfectants, and support the formation of biofilms. Residues of allergenic foods on a surface may increase the risk of allergen cross-contact. However, ATP tests cannot detect bacteria or allergenic proteins directly. To ensure efficient use of commercially available ATP tests, in-depth knowledge is needed regarding their practical applications, methods for determining pass-fail limits, and differences in performance. Conventional ATP tests have limitations due to possible hydrolysis of ATP to ADP and AMP, which further hinders the identification of food residues. To overcome this problem, a total adenylate test was developed that could detect ATP+ADP+AMP (A3 test). The A3 test is suitable for the detection of adenylates from food residues and useful for verification of hygiene levels. The A3 test in conjunction with other methods, such as microorganism culture and food allergen tests, may be a useful strategy for identifying contamination sources and facilitating effective hygiene management.

HIGHLIGHTS

Trypsin-Like Activity in Oral Cavity Is Associated with Risk of Fever Onset in Older Residents of Nursing Homes: An 8-Month Longitudinal Prospective Cohort Pilot Study

This study aimed to evaluate the association between trypsin-like activity in the oral cavity and the onset of fever in independent older residents of nursing homes. Independent older residents aged ≥ 65 years in 10 nursing homes were included in this study, which was conducted in Kitakyushu, Japan. For 8 months, follow-up dates on which the body temperatures of participants were more than 37.2 °C were noted. Trypsin-like activity in the oral cavity was detected by ADCHECK® with five-grade evaluation at baseline. Data from 53 independent participants with median age 89.0 (67–102) years were available for analysis. ADCHECK® scores were associated with fever days (r = 0.312, p = 0.029). The average periods until the onset of fever in participants with ADCHECK® Scores 1 and 2, Score 3, and Scores 4 and 5 were 6.6 ± 0.5, 5.0 ± 0.7, and 4.1 ± 1.0 months, respectively. ADCHECK® Scores 4 and 5 signified a higher risk of fever compared to ADCHECK® Scores 1 and 2 (hazards ratio 5.9, 95% confidence interval 1.4–23.9, p = 0.013), adjusted for possible confounders. We concluded that trypsin-like activity in the oral cavity was associated with the risk of fever in independent older residents of nursing homes.

Photodynamic antimicrobial chemotherapy using indocyanine green in experimentally induced intraoral ulcers in rats

BACKGROUND

Photodynamic antimicrobial chemotherapy (PACT) is a promising modality for eradication of microorganisms from the wound. This study aimed to investigate the effectiveness of PACT using indocyanine green (ICG) for reduction of bacterial load of oral ulcers in rats and its impact on the healing process.

METHODS

In this experimental study, 50 adult male Sprague Dawley rats were recruited. Oral ulcers were surgically made on the left cheek mucosa, and animals were randomly assigned into five groups (n = 10). Wound site in groups 1, 2, and 3 was irrigated with the sterile saline (0.9%), chlorhexidine (CHX; 0.2%), and ICG solutions (1 mg/mL), respectively. Group 4 was exposed to laser irradiation using 810 nm diode laser on continuous-wave mode for 30 seconds (fluence: 55 J/cm² , power: 300 mW, spot size: 4.5 mm). In group 5, PACT was performed using topical application of ICG followed by laser irradiation in the same way as the previous group. Bacterial load of oral ulcers was assessed before and after each treatment modality. Besides, rats were sacrificed on the 5th day post ulceration and histological features of healing were evaluated.

RESULTS

Bacterial load was significantly reduced merely in the PACT-ICG-treated group by one log (P < .0001). Animals in the PACT-ICG-treated group also showed an accelerated healing in comparison with others on the 5th day of an experiment.

CONCLUSION

Photodynamic antimicrobial chemotherapy using topical application of ICG has a potential to reduce the bacterial load of oral ulcers and accelerate wound repair. Therefore, it can be considered as an alternative to currently available modalities for wound management.

A rapid chair-side method for the estimation of oral bacterial colonization density

AIMS

Caries and periodontal disease are associated with inadequate control of oral bacteria. Since conventional microbiological evaluations are impractical in dental clinics or public engagement activities, a rapid test for the quantification of oral bacteria represents a useful tool. We describe the development of a colour change test to rapidly estimate bacterial colonisation density in the mouth.

METHODS AND RESULTS

Volunteers rinsed with milk or milkshake. Viability indicators were added and colour changes quantified during incubation. Using milkshake and the resazurin-based solution PrestoBlue (9% v/v), the method distinguished between samples before and after brushing within 5 min. Colour changes were quantified and viable counts were obtained using oral rinses. Measured colour changes strongly correlated with total counts of both anaerobes and streptococci (Spearman's correlation coefficient of 0·782 and 0·769, respectively, P ≤ 0·001) and with perceived changes, as determined by volunteers (n = 10) visually ranking images.

CONCLUSIONS

The resazurin milkshake test can rapidly and visually quantify viable bacteria in oral samples.

SIGNIFICANCE AND IMPACT OF THE STUDY

The resazurin milkshake test could serve as a sensitive semi-quantitative method for measuring oral bacteria in human oral rinse samples.