Determinants of Antimicrobial Use for Covid-19 Related Symptoms among Nigerians.

BACKGROUND: Antimicrobial use plays a key role in development and spread of antimicrobial resistance. Following the global coronavirus disease 2019 (COVID-19) pandemic and the report of the first confirmed case in Nigeria, several states embarked on either a full or partial lockdown as a measure to prevent or curtail the spread of the virus with its attendant challenges. This survey was designed to provide a snapshot of public antimicrobial use and common perception related to antimicrobial use for COVID-19 related symptoms among Nigerian populace. METHODS: We developed and tested a 29-question electronic questionnaire with Google forms asking respondents about their antimicrobial use and perceptions regarding appropriate antimicrobial use for real or perceived symptoms during the outbreak period. Respondents aged 18 years and above were recruited through crowd sourcing and they received the link to the survey tool through emails and social media including WhatsApp, Twitter, Facebook, LinkedIn, and Instagram. All data analysis was performed using SPSS version 26.0. RESULTS: A total of 410 responses were received from the six geopolitical zones in Nigeria comprising 200 (48.8%) females and 210 (51.2%) males. Majority (62.9%) of the respondents had taken antimicrobials in the 3 months period preceding the survey, while less than half (46.8%) received prescription for it. Previous intake of antimicrobial for similar illness was a predictor of antimicrobial intake (OR: 0.55, 95%CI: 0.30-1.01). The most consumed antimicrobial was antimalarial drugs, specifically Artemisinin-based combination therapy (43.4%), followed by antibiotics [Ciprofloxacin (20.2%)]. CONCLUSION: There was high levels of antimicrobial use for COVID-19 related symptoms by the Nigerian public. This is likely to escalate the already high prevalence of antimicrobial use previously reported and may further fuel the emergence of antimicrobial resistance.

CONTEXTE: L'utilisation d'antimicrobiens joue un rôle clé dans le développement et la propagation de la résistance aux antimicrobiens. À la suite de la pandémie mondiale de coronavirus 2019 (COVID-19) et du rapport du premier cas confirmé au Nigéria, plusieurs États se sont engagés dans un verrouillage complet ou partiel en tant que mesure pour prévenir ou freiner la propagation du virus avec ses défis associés. Cette enquête a été conçue pour fournir un aperçu de l'utilisation publique des antimicrobiens et de la perception commune liée à l'utilisation des antimicrobiens pour les symptômes liés au COVID-19 parmi la population nigériane. MÉTHODES: Nous avons développé et testé un questionnaire électronique de 29 questions avec des formulaires Google interrogeant les répondants sur leur utilisation d'antimicrobiens et leurs perceptions concernant l'utilisation appropriée d'antimicrobiens pour les symptômes réels ou perçus pendant la période d'épidémie. Les répondants âgés de 18 ans et plus ont été recrutés via le crowdsourcing et ils ont reçu le lien vers l'outil d'enquête via des e-mails et des médias sociaux, notamment WhatsApp, Twitter, Facebook, LinkedIn et Instagram. Toutes les analyses de données ont été effectuées à l'aide de la version 26.0 de SPSS. RÉSULTATS: Un total de 410 réponses ont été reçues des six zones géopolitiques du Nigéria comprenant 200 (48,8%) femmes et 210 (51,2%) hommes. La majorité (62,9%) des répondants avaient pris des antimicrobiens au cours des 3 mois précédant l'enquête, tandis que moins de la moitié (46,8%) en avaient reçu une prescription. La prise antérieure d'antimicrobiens pour une maladie similaire était un prédicteur de l'ingestion d'antimicrobiens (OR: 0,55, IC à 95%: 0,30-1,01). L'antimicrobien le plus consommé était les antipaludiques, en particulier les associations thérapeutiques à base d'artémisinine (43,4%), suivis des antibiotiques [Ciprofloxacine (20,2%)]. CONCLUSION: Il y avait des niveaux élevés d'utilisation d'antimicrobiens pour les symptômes liés au COVID-19 par le public nigérian. Cela est susceptible d'augmenter la prévalence déjà élevée de l'utilisation d'antimicrobiens rapportée précédemment et peut encore alimenter l'émergence de la résistance aux antimicrobiens.

Antimicrobial Activity of a Colloidal AgNP Suspension Demonstrated In Vitro against Monoculture Biofilms: Toward a Novel Tooth Disinfectant for Treating Dental Caries.

A novel silver nanoparticle (AgNP) formulation was developed as a targeted application for the disinfection of carious dentine. Silver nitrate (AgNO3) was chemically reduced using sodium borohydrate (NaBH4) in the presence of sodium dodecyl sulfate (SDS) to form micelle aggregate structures containing monodisperse 6.7- to 9.2-nm stabilized AgNPs. AgNPs were characterized by measurement of electrical conductivity and dynamic light scattering, scanning electron microscopy, transmission electron microscopy, and inductively coupled plasma mass spectrometry. Antimicrobial activity of AgNPs was tested against planktonic cultures of representative gram-positive and gram-negative oral bacteria using well diffusion assays on tryptic soy broth media and monoculture biofilms grown with brain heart infusion ± sucrose anaerobically at 37°C on microtiter plates. Biofilm mass was measured by crystal violet assay. Effects were compared to silver diamine fluoride and chlorhexidine (negative controls) and 70% isopropanol (positive control) exposed cultures. In the presence of AgNPs, triplicate testing against Streptococcus gordonii DL1, C219, G102, and ATCC10558 strains; Streptococcus mutans UA159; Streptococcus mitis I18; and Enterococcus faecalis JH22 for planktonic bacteria, the minimum inhibitory concentrations were as low as 7.6 µg mL-1 and the minimum bacteriocidal concentrations as low as 19.2 µg mL-1 silver concentration. Microplate readings detecting crystal violet light absorption at 590 nm showed statistically significant differences between AgNP-exposed biofilms and where no antimicrobial agents were used. The presence of sucrose did not influence the sensitivity of any of the bacteria. By preventing in vitro biofilm formation for several Streptococcus spp. and E. faecalis, this AgNP formulation demonstrates potential for clinical application inhibiting biofilms.

Microrobotics for Precision Biofilm Diagnostics and Treatment.

Advances in small-scale robotics and nanotechnology are providing previously unimagined opportunities for new diagnostic and therapeutic approaches with high precision, control, and efficiency. We designed microrobots for tetherless biofilm treatment and retrieval using iron oxide nanoparticles (NPs) with dual catalytic-magnetic functionality as building blocks. We show 2 distinct microrobotic platforms. The first system is formed from NPs that assemble into aggregated microswarms under magnetic fields that can be controlled to disrupt and retrieve biofilm samples for microbial analysis. The second platform is composed of 3-dimensional (3D) micromolded opacifier-infused soft helicoids with embedded catalytic-magnetic NPs that can be visualized via existing radiographic imaging techniques and controlled magnetically inside the root canal, uninterrupted by the soft and hard tissues surrounding the teeth in an ex vivo model. These microrobots placed inside the root canal can remove biofilms and be efficiently guided with microscale precision. The proof-of-concept paradigm described here can be adapted to target difficult-to-reach anatomical spaces in other natural and implanted surfaces in an automated and tether-free manner.

Effects of a ZnCuO-Nanocoated Ti-6Al-4V Surface on Bacterial and Host Cells.

This study aims to investigate the effects of a novel ZnCuO nanoparticle coating for dental implants-versus those of conventional titanium surfaces-on bacteria and host cells. A multispecies biofilm composed of Streptococcus sanguinis, Actinomyces naeslundii, Porphyromonas gingivalis, and Fusobacterium nucleatum was grown for 14 days on various titanium discs: machined, sandblasted, sandblasted and acid-etched (SLA), ZnCuO-coated, and hydroxyapatite discs. Bacterial species were quantified with qPCR, and their viability was examined via confocal microscopy. Osteoblast-like and macrophage-like cells grown on the various discs for 48 h were examined for proliferation using an XTT assay, and for activity using ALP and TNF-α assays. The CSLM revealed more dead bacteria in biofilms grown on titanium than on hydroxyapatite, and less on sandblasted than on machined and ZnCuO-coated surfaces, with the latter showing a significant decrease in all four biofilm species. The osteoblast-like cells showed increased proliferation on all of the titanium surfaces, with higher activity on the ZnCuO-coated and sandblasted discs. The macrophage-like cells showed higher proliferation on the hydroxyapatite and sandblasted discs, and lower activity on the SLA and ZnCuO-coated discs. The ZnCuO-coated titanium has anti-biofilm characteristics with desired effects on host cells, thus representing a promising candidate in the complex battle against peri-implantitis.

Curry Leaf Triggers Cell Death of P. gingivalis with Membrane Blebbing.

Periodontal disease has become a serious public health problem, as indicated by accumulating evidence that periodontal disease is not only a major cause of tooth loss but is also associated with various systemic diseases. The present study assessed the anti-bacterial activities of three herbal products (curry leaf, clove, and cinnamon) against Porphyomonas gingivalis, a keystone pathogen for periodontal diseases. The curry leaf extract (CLE) showed the strongest growth inhibitory activity among them, and the activity was maintained even after extensive heat treatment. Of note, while clove and cinnamon extracts at sub-minimum inhibitory concentrations (sub-MICs) significantly enhanced the biofilm formation of P. gingivalis, CLE at sub-MIC did not have any effect on the biofilm formation. The MIC of CLE against P. gingivalis was higher than those against a wide range of other oral bacterial species. P. gingivalis cells were completely killed within 30 min after treatment with CLE. Spatiotemporal analysis using high-speed atomic force microscopy revealed that CLE immediately triggered aberrant membrane vesicle formation on the bacterial surface. Bacterial membrane potential assay revealed that CLE induced depolarization of the bacterial membrane. Taken together, these findings suggest the mechanism behind early bactericidal activity of CLE and its therapeutic applicability in patients with periodontal diseases.

Rapid Bactericidal Action of Propolis against Porphyromonas gingivalis.

Propolis, a resinous substance produced by bees, is used as a folk medicine for treatment of periodontal diseases. However, its mode of the action and the compounds responsible for its activities remain obscure. In the present study, we comprehensively investigated the antibacterial activities of ethanol-extracted propolis (EEP) and EEP-derived compounds toward Porphyromonas gingivalis, a keystone pathogen for periodontal diseases. Broth microdilution and agar dilution assays were used to determine the minimum inhibitory concentrations of EEP against a range of oral bacterial species, of which P. gingivalis showed a higher level of sensitivity than oral commensals such as streptococci. Its antibacterial activity toward P. gingivalis was maintained even after extensive heat treatment, demonstrating a high level of thermostability. EEP also induced death of P. gingivalis cells by increasing membrane permeability within 30 min. Spatiotemporal analysis based on high-speed atomic force microscopy revealed that EEP immediately triggered development of aberrant membrane blebs, followed by bleb fusion events on the bacterial surface. Furthermore, we isolated artepillin C, baccharin, and ursolic acid from EEP as antibacterial compounds against P. gingivalis. Of those, artepillin C and baccharin showed bacteriostatic activities with membrane blebbing, while ursolic acid showed bactericidal activity with membrane rupture. In particular, ursolic acid demonstrated a greater ability to affect bacterial membrane potential with increased membrane permeability, probably because of its highly lipophilic nature as compared with other compounds. Taken together, these findings provide mechanistic insight into the antibacterial activities of EEP and its exquisite membrane-targeting antibacterial compounds and imply the applicability of narrow-spectrum therapeutics with EEP for treatment of periodontitis. In addition, the advanced technology utilized in the present study to visualize the nanometer-scale dynamics of microorganisms will contribute to expanding our understanding of the activities of antimicrobials and the mechanism of drug resistance in bacteria.

High-Velocity Microsprays Enhance Antimicrobial Activity in Streptococcus mutans Biofilms.

Streptococcus mutans in dental plaque biofilms play a role in caries development. The biofilm's complex structure enhances the resistance to antimicrobial agents by limiting the transport of active agents inside the biofilm. The authors assessed the ability of high-velocity water microsprays to enhance delivery of antimicrobials into 3-d-old S. mutans biofilms. Biofilms were exposed to a 90° or 30° impact, first using a 1-µm tracer bead solution (109 beads/mL) and, second, a 0.2% chlorhexidine (CHX) or 0.085% cetylpyridinium chloride (CPC) solution. For comparison, a 30-s diffusive transport and simulated mouthwash were also performed. Confocal microscopy was used to determine number and relative bead penetration depth into the biofilm. Assessment of antimicrobial penetration was determined by calculating the killing depth detected by live/dead viability staining. The authors first demonstrated that the microspray was able to deliver significantly more microbeads deeper in the biofilm compared with diffusion and mouthwashing exposures. Next, these experiments revealed that the microspray yielded better antimicrobial penetration evidenced by deeper killing inside the biofilm and a wider killing zone around the zone of clearance than diffusion alone. Interestingly the 30° impact in the distal position delivered approximately 16 times more microbeads and yielded approximately 20% more bacteria killing (for both CHX and CPC) than the 90° impact. These data suggest that high-velocity water microsprays can be used as an effective mechanism to deliver microparticles and antimicrobials inside S. mutans biofilms. High shear stresses generated at the biofilm-burst interface might have enhanced bead and antimicrobial delivery inside the remaining biofilm by combining forced advection into the biofilm matrix and physical restructuring of the biofilm itself. Further, the impact angle has potential to be optimized both for biofilm removal and active agents' delivery inside biofilm in those protected areas where some biofilm might remain.

Metagenomic Insights into Transferable Antibiotic Resistance in Oral Bacteria.

Antibiotic resistance is considered one of the greatest threats to global public health. Resistance is often conferred by the presence of antibiotic resistance genes (ARGs), which are readily found in the oral microbiome. In-depth genetic analyses of the oral microbiome through metagenomic techniques reveal a broad distribution of ARGs (including novel ARGs) in individuals not recently exposed to antibiotics, including humans in isolated indigenous populations. This has resulted in a paradigm shift from focusing on the carriage of antibiotic resistance in pathogenic bacteria to a broader concept of an oral resistome, which includes all resistance genes in the microbiome. Metagenomics is beginning to demonstrate the role of the oral resistome and horizontal gene transfer within and between commensals in the absence of selective pressure, such as an antibiotic. At the chairside, metagenomic data reinforce our need to adhere to current antibiotic guidelines to minimize the spread of resistance, as such data reveal the extent of ARGs without exposure to antimicrobials and the ecologic changes created in the oral microbiome by even a single dose of antibiotics. The aim of this review is to discuss the role of metagenomics in the investigation of the oral resistome, including the transmission of antibiotic resistance in the oral microbiome. Future perspectives, including clinical implications of the findings from metagenomic investigations of oral ARGs, are also considered.