Plant extracts are in the focus of the pharmaceutical industry as potential antimicrobials for oral care due to their high antimicrobial activity coupled with low production costs and safety for eukaryotic cells. Here, we show that the extract from Hop (Humulus lupulus L.) exhibits antimicrobial activity against Staphylococcus aureus and Streptococci in both planktonic and biofilm-embedded forms. An extract was prepared by acetone extraction from hop infructescences, followed by purification and solubilization of the remaining fraction in ethanol. The effect of the extract on S. aureus (MSSA and MRSA) was comparable with the reference antibiotics (amikacin, ciprofloxacin, and ceftriaxone) and did not depend on the bacterial resistance to methicillin. The extract also demonstrated synergy with amikacin on six S. aureus clinical isolates, on four of six isolates with ciprofloxacin, and on three of six isolates with ceftriaxone. On various Streptococci, while demonstrating lower antimicrobial activity, an extract exhibited a considerable synergistic effect in combination with two of three of these antibiotics, decreasing their MIC up to 512-fold. Moreover, the extract was able to penetrate S. aureus and S. mutans biofilms, leading to almost complete bacterial death within them. The thin-layer chromatography and LC-MS of the extract revealed the presence of prenylated flavonoids (2′,4′,6′,4-tetrahydroxy-3′-geranylchalcone) and acylphloroglucides (cohumulone, colupulone, humulone, and lupulone), apparently responsible for the observed antimicrobial activity and ability to increase the efficiency of antibiotics. Taken together, these data suggest an extract from H. lupulus as a promising antimicrobial agent for use both as a solely antiseptic and to potentiate conventional antimicrobials.

The Antimicrobial Potential of the Hop (Humulus lupulus L.) Extract against Staphylococcus aureus and Oral Streptococci

Biofilms, which consist of microorganisms enclosed in an extracellular polymeric material (EPS), hold immense importance in the fields of environmental research, industry, and medicine. They play a significant role in ecosystem dynamics and stability, but they also pose issues such as biofouling, corrosion, and pollution. Biofilms in medical environments are linked to persistent infections and elevated healthcare expenses. The EPS matrix plays a crucial role in maintaining the structural integrity and antibiotic resistance of these structures. The research primarily investigates the role of the EPS matrix in facilitating horizontal gene transfer among biofilm communities, with a particular emphasis on EPS and its impact on this process. The process is recognized as a pivotal mechanism in the emergence of antibiotic resistance, underscoring the crucial function of EPS in the dynamics of biofilms. The analysis also highlights the significant financial constraints caused by biofilms in several industries. Biofilm-associated infections in the healthcare sector result in escalated treatment expenses and extended hospitalization periods. In an industrial context, biofilms have a role in increasing maintenance expenses and product contamination, emphasizing the need for efficient management solutions. This review presents the most recent progress in biofilm research, emphasizing the utilization of sophisticated imaging tools and molecular methodologies. In addition to conventional imaging techniques, the research explores the utilization of sophisticated molecular tools, such as DNA and RNA sequencing, in conjunction with proteomics. These approaches are essential for assessing the genetic and metabolic mechanisms that regulate biofilm development and antibiotic resistance. The review underscores the significance of employing an interdisciplinary methodology in the study of biofilms. By incorporating a range of approaches, such as sophisticated imaging and molecular analysis, a comprehensive understanding of biofilm dynamics may be achieved. This approach also opens up possibilities for developing novel solutions to address the negative impacts of biofilms on health, industry, and the environment.

Investigating Biofilms: Advanced Methods for Comprehending Microbial Behavior and Antibiotic Resistance

The immobilization of ficin extract (sulfidryl proteases) on glyoxyl agarose beads stabilized it, but there is a clear stability maximum after 3 h of immobilization, being the 24 h biocatalyst less stable when thermally inactivated in presence of air. The incubation of the thermally inactivated biocatalysts in the presence of dithiothreitol permitted to recover almost total activity of the biocatalysts prepared for 24 h of immobilization, while the enzyme immobilized for 3 h recovered less activity. This suggested that the main cause of the faster enzyme inactivation of the 24 h biocatalyst was the Cys oxidation. This was confirmed by inactivating the Cys blocked biocatalysts by using 2,2’-dipyridyldisulfide. Again, a higher percentage of the initial activity (when unblocked by incubation in mercaptoethanol the thermally inactivated biocatalysts) was observed for the 24 h biocatalyst. The use of helium atmosphere enabled to greatly improve the enzyme stability of all immobilized biocatalysts, confirming the highest stability of the biocatalyst immobilized for 24 h. Results suggested that this biocatalyst was in fact the most rigid one, but that the distortion induced by the immobilization produced a higher exposition of the catalytic Cys, and this way, its oxidation becomes faster in the presence of oxygen. 

Glyoxyl-ficin: An example where a more intense multipoint covalent attachment may decrease enzyme stability.

We previously developed a novel lactotransferrin-derived antimicrobial peptide, LF-1, with selective antibacterial activity against the characteristic cariogenic bacterium Streptococcus mutans. This study further investigated the effects of LF-1 on the cariogenic virulence factors of S. mutans and evaluated the changes in virulence-associated enzymes and genes; the viability, acidogenicity, and aciduricity of planktonic S. mutans; and initial colonisation and biofilm formation after treatment with LF-1. The method of qRT-PCR was used to evaluate S. mutans virulence-associated gene expression. LF-1 interfered with the cell viability of S. mutans within 6 h. LF-1 inhibited the acidogenicity and aciduricity of S. mutans, with reduced lactic acid production and survival in a lethal acidic environment, and inactivated lactate dehydrogenase and F1F0-ATPase activity. LF-1 decreased surface-adherent S. mutans within 60 min and inhibited S. mutans biofilm formation, where scanning electron microscopy and confocal laser scanning microscopy showed reduced extracellular matrix and bacteria. LF-1 downregulates S. mutans virulence-associated gene expression. LF-1 inhibited the growth and cariogenic virulence factors of S. mutans in vitro with a reduction in key enzymatic activity and downregulation of virulence-associated gene expression. LF-1 has promising application prospects in the fight against S. mutans and dental caries.

/pdf/novel-lactotransferrin-derived-antimicrobial-peptide-lf-1-39yz9eq9.pdf

Novel Lactotransferrin-Derived Antimicrobial Peptide LF-1 Inhibits the Cariogenic Virulence Factors of Streptococcus mutans

Oral mucosal infection, especially oral candidiasis, is currently the most common oral mucosal disease. Traditional drug treatment regimens have difficulty adhering to mucous membranes, coupled with the unique anatomical and physiological characteristics of the oral cavity, thus reducing drug availability and limiting the effective time of drug action. Inspired by cell membrane-coated nanoparticles, this study aimed to construct a bionic adherent oral mucosal drug delivery system and investigated its therapeutic potential for oral candidiasis. The system was obtained by encapsulating Streptococcus salivarius K12 membranes on triclosan-loaded PLGA nanoparticles using an extrusion method. The constructed nanocomplexes (K12/[email protected]) inherited the properties of the source cell membrane, bionically adhering to the oral mucosa and binding to the candida albicans hypha. Our in vitro and in vivo experiments have confirmed that K12/[email protected] nanocomplexes significantly inhibits the formation of C. albicans biofilms and the development of oral candidiasis by enhancing the accumulation of drugs in lesions, optimizing drug efficacy. Furthermore, the biomimetic nanocomplexes could be considered safe and effective drug delivery systems, which hold considerable therapeutic promise for oral mucosal infections including candidiasis. 

Antimicrobial effect of Streptococcus salivarius outer membrane-coated nanocomplexes against Candida albicans and oral candidiasis

Abstract Background To investigate the effect of ficin, a type of proteases, on Candida albicans ( C. albicans ) biofilm, including forming and pre-formed biofilms. Methods Crystal violet tests together with colony forming unit (CFU) counts were used to detect fungal biofilm biomass. Live/dead staining of biofilms observed by confocal laser scanning microscopy was used to monitor fungal activity. Finally, gene expression of C. albicans within biofilms was assessed by qRT-PCR. Results According to our results, biofilm biomass was dramatically reduced by ficin in both biofilm formation and pre-formed biofilms, as revealed by the crystal violet assay and CFU count ( p &lt; 0.05). Fungal activity in biofilm formation and pre-formed biofilms was not significantly influenced by ficin according to live/dead staining. Fungal polymorphism and biofilm associated gene expression were influenced by ficin, especially in groups with prominent antibiofilm effects. Conclusions In summary, ficin effectively inhibited C. albicans biofilm formation and detached its preformed biofilm, and it might be used to treat C. albicans biofilm associated problems. 

/pdf/inhibitory-effect-of-ficin-on-candida-albicans-biofilm-hc1tmihc.pdf

Inhibitory effect of ficin on Candida albicans biofilm formation and pre-formed biofilms

Ureaplasma urealyticum is a common genital mycoplasma in men and women, which can cause reproductive tract infection and infertility, and is also related to adverse pregnancy outcomes and neonatal diseases. Pathogen culture and polymerase chain reaction (PCR) are the main methods for the diagnosis of U. urealyticum. However, pathogen culture takes too long, and PCR requires professional personnel and sophisticated instruments. Here, we report a simple, convenient, sensitive, and specific detection method, which combines catalytic hairpin assembly with a lateral flow immunoassay strip. Only a water bath and a fluorescence reader are needed to detect the results in 30 min. We can realize the point-of-care testing of U. urealyticum by this method. To verify this method, we selected 10 clinical samples for testing, and the test results were exactly the same as the clinical report.

Detection of Ureaplasma urealyticum by Catalytic Hairpin Assembly Combined with a Lateral Flow Immunoassay Strip

/pdf/inhibitory-effect-of-ficin-on-candida-albicans-biofilm-2lcwjo4d.pdf


 
 
 Zoliflodacin (ZFD) is a new type of antibiotic whose anticaries potential through controlling biofilms remains unknown. This study aimed to explore the effects of ZFD on the conditional formation of cariogenic
 Streptococcus mutans
 (
 S. mutans
 ) biofilms.
 
 
 
 
 
 Crystal violet analysis, colony forming unit (CFU) counting, and MTT assays were used to determine biofilm biomass, viable bacterial cell counts, and bacterial metabolic viability, respectively, while acid generation by biofilms was monitored by measuring pH and lactic acid production. The anthrone-sulfuric acid method and polysaccharide/bacterial staining were used to investigate extracellular polysaccharide (EPS) production. The microstructure of
 S. mutans
 biofilms was observed using scanning electron microscopy (SEM). Growth curves were used to visualize bacterial growth, while live/dead bacterial staining was used to determine microbial activity. Furthermore, the cytotoxicity of ZFD was evaluated by live/dead cellular staining together with the CCK-8 assay, while drug resistance was induced using bacterial reduplicative exposure to ZFD. Quantitative real-time polymerase chain reaction (qRT-PCR) was used to calculate gene expression levels. In addition, checkerboard microdilution assays were performed to evaluate potential synergistic or antagonistic interactions of ZFD in combination with NaF or chlorhexidine (CHX) against bacterial growth and biofilm formation.
 
 
 
 
 
 We found ZFD significantly inhibited
 S. mutans
 biofilm formation, decreasing overall biofilm biomass, viable bacterial cell counts within biofilms, and biofilm metabolic viability. ZFD not only markedly suppressed
 S. mutans
 cariogenic virulence involving acid and EPS synthesis, but also affected bacterial morphology within biofilms. Furthermore, ZFD inhibited bacterial growth without significantly suppressing the survival rate of bacterial cells within biofilms. Moreover, ZFD demonstrated no significant cytotoxicity and did not trigger drug resistance in
 S. mutans
 after 20 passages. qRT-PCR analysis revealed significant differences in the expression of virulence-, quorum sensing-, and oxidative stress protection-associated genes. Indifferent effects were found when ZFD was combined with NaF or CHX on
 S. mutans
 growth and biofilm formation.
 
 
 
 
 
 In summary, ZFD is a potential antibacterial agent for caries control because of its antibiofilm effects, inconspicuous cytotoxicity, low risk of resistance induction and antibacterial activity against
 S. mutans
 .
 


Zoliflodacin inhibits Streptococcus mutans biofilms

Abstract Multidrug-resistant Acinetobacter baumannii (MDR-AB) infections are becoming increasingly common. The Real-Time Nosocomial Infection (NI) Surveillance System (RT-NISS) was used to monitor MDR-AB NI in intensive care units (ICUs) to prevent NI outbreaks. Therefore, the RT-NISS was used in the current study to monitor MDR-AB infections in a neurosurgery ICU. Clinical interventions, including recommended antibiotics, bacterial distribution in the patient analysis, and bed adjustments, were carried out based on the monitoring results. The RT-NISS was also used to monitor clinical data, implement, and provide training on NI control. The RT-NISS detected a potential cluster of XDR-AB when five patients admitted to the neurosurgery ICU were tested positive for AB between 11 and 17 June 2019. Only two infected cases originated in the hospital, and there was no NI outbreak. The hospital Infection Control Department took appropriate measures to prevent cross-infection; specifically, an epidemiologic investigation and environmental assessment were conducted, and NI prevention and outbreak management training was provided. In summary, the RT-NISS enhanced the timeliness and efficacy of NI control and surveillance in a neurosurgery ICU. In order to prevent NI outbreaks, the Real-Time Nosocomial Infection (NI) Surveillance System (RT-NISS) was employed to monitor MDR-AB NI in critical care units (ICU). Based on the monitoring data, clinical actions such as required antibiotics, bacterial distribution in the patient analysis, and bed changes were carried out. In a neurosurgery ICU, the RT-NISS improved the timeliness and efficacy of NI control and surveillance.

/pdf/monitoring-multidrug-resistant-acinetobacter-baumannii-1kx8isba.pdf

Monitoring Multidrug-Resistant Acinetobacter Baumannii Infections in The Neurosurgery ICU Using a Real-Time Surveillance System

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Inhibitory effect of ficin on Candida albicans biofilm formation and pre-formed biofilms

Detection of Ureaplasma urealyticum by Catalytic Hairpin Assembly Combined with a Lateral Flow Immunoassay Strip

Inhibitory effect of ficin on Candida albicans biofilm formation and pre-formed biofilms

Zoliflodacin inhibits Streptococcus mutans biofilms

Monitoring Multidrug-Resistant Acinetobacter Baumannii Infections in The Neurosurgery ICU Using a Real-Time Surveillance System