Sonication versus the conventional method for evaluation of the dental microbiome: a prospective pilot study

Swabs versus native specimens in severe head and neck infections: a prospective pilot study and suggestions for clinical management

INTRODUCTION

Head and neck infections, particularly odontogenic infections, can lead to serious complications if not properly managed. While swabs are commonly used for microbial identification, their reliability in polymicrobial infections is debated. This study evaluates the advantages of native tissue samples over swabs in the management of severe head and neck infections.

MATERIAL AND METHODS

This prospective cohort study included patients with severe acute head and neck infections requiring hospitalization, surgical drainage, and microbiologic analysis. Swabs and native tissue/fluid samples were collected for pathogen cultivation, Gram staining, and resistance testing. Clinical data, infection characteristics, and antimicrobial resistance profiles were analyzed using descriptive and inferential statistics.

RESULTS

60 patients, 55% male (45.7 years) and 45% female (48.1 years) were analyzed. After antibiotic treatment, CRP and leukocyte levels decreased significantly, with higher CRP correlating with longer hospital stays. ICU admission correlated with hospital stay > 7 days. More Actinomyces and fungal species were identified in native tissue samples and more Streptococci in swabs. Antibiotic resistance, especially to clindamycin (1/3 of the cases), was associated with longer hospital and ICU stays. Clindamycin resistance correlated with increased ICU admission, while metronidazole resistance (10% of the cases) was associated with longer ICU stays. ICU admission was also associated with higher Cormack-Lehane scores.

CONCLUSION

Severe head and neck infections require a comprehensive multidisciplinary approach. Native tissue should be obtained whenever possible. While microbiological findings varied between sampling methods, native samples may provide a broader spectrum of detected pathogens, which could be relevant for infection management. Given the increasing resistance to clindamycin, its indications should be critically re-evaluated. The implementation of targeted antimicrobial strategies and a risk-based classification system may help optimize patient management and improve outcomes.

Optimizing the use of low-frequency ultrasound for bacterial detachment of in vivo biofilms in dental research-a methodological study

OBJECTIVES

Low-frequency, low-intensity ultrasound is commonly utilized in various dental research fields to remove biofilms from surfaces, but no clear recommendation exists in dental studies so far. Therefore, this study aims to optimize the sonication procedure for the dental field to efficiently detach bacteria while preserving viability.

MATERIALS AND METHODS

Initial biofilm was formed in vivo on bovine enamel slabs (n = 6) which were worn by four healthy participants for 4 h and 24 h. The enamel slabs covered with biofilm were then ultrasonicated ex vivo for various time periods (0, 1, 2, 4, 6 min). Colony-forming units were determined for quantification, and bacteria were identified using MALDI-TOF. Scanning electron microscopic images were taken to also examine the efficiency of ultrasonications for different time periods.

RESULTS

Ultrasonication for 1 min resulted in the highest bacterial counts, with at least 4.5-fold number compared to the non-sonicated control (p < 0.05). Most bacteria were detached within the first 2 min of sonication, but there were still bacteria detached afterwards, although significantly fewer (p < 0.0001). The highest bacterial diversity was observed after 1 and 2 min of sonication (p < 0.03). Longer sonication periods negatively affected bacterial counts of anaerobes, Gram-negative bacteria, and bacilli. Scanning electron microscopic images demonstrated the ability of ultrasound to desorb microorganisms, as well as revealing cell damage and remaining bacteria.

CONCLUSIONS

With the use of low-frequency, low-intensity ultrasound, significantly higher bacterial counts and diversity can be reached. A shorter sonication time of 1 min shows the best results overall.

CLINICAL RELEVANCE

This standardization is recommended to study initial oral biofilms aged up to 24 h to maximize the outcome of experiments and lead to better comparability of studies.