Significant Reduction In Bacterial Growth Research Articles

Effect of pH and hydroxyapatite-like layer formation on the antibacterial properties of borophosphate bioactive glass incorporated poly(methyl methacrylate) bone cement

Infection is a leading cause of total joint arthroplasty failure. Current preventative measures incorporate antibiotics into the poly (methyl methacrylate) (PMMA) bone cement that anchors the implant into the natural bone. With bacterial resistance to antibiotics on the rise, the development of alternative antibacterial materials is crucial to mitigate infection. Borate bioactive glass, 13–93-B3, has been studied previously for use in orthopedic applications due to its ability to be incorporated into bone cements and other scaffolds, convert into hydroxyapatite (HA)-like layer, and enhance the osseointegration and antibacterial properties of the material. The purpose of this study is to better understand how glass composition and change in surrounding pH effects the composite’s antibacterial characteristics by comparing the incorporation of 30% wt/wt 13–93-B3 glass and pH neutral borophosphate bioactive glass into PMMA bone cement. We also aim to elucidate how HA-like layer formation on the cement’s surface may affect bacterial adhesion. These studies showed that 13–93-B3 incorporated cements had significant reduction of bacterial growth surrounding the composite beyond 24 h of exposure when compared to a neutral borate bioactive glass incorporated cement (p < 0.01) and cement only (p < 0.0001). Additionally, through soaking cement composites in simulated body fluid and then exposing them to a bioluminescent strand of staphylococcus aureus, we found that the presence of a HA-like layer on the 13–93-B3 or pH neutral glass incorporated cement disks resulted in an increase in bacterial attachment on the composite cement’s surface, where p < 0.001, and p < 0.05 respectively. Overall, our studies demonstrated that borate bioactive glass incorporated PMMA bone cement has innate antimicrobial properties that make it a promising material to prevent infection in total joint arthroplasties.

Formulation of Dual-Functional Nonionic Cetomacrogol Creams Incorporated with Bacteriophage and Human Platelet Lysate for Effective Targeting of MDR P. aeruginosa and Enhanced Wound Healing.

Successful development of phage-based therapeutics and their utility predominantly depend on the mode and route of phage administration. Topical and site-directed phage application evokes minimal immune clearance and allows more phage-host adsorption, thereby ensuring higher phage efficacy. However, a notable drawback of conventional topical phage applications is the absence of sustained release. Occlusive emollients guarantee the controlled release of active pharmaceutical ingredients (APIs), thereby facilitating administration, preventing moisture loss, and acting as a skin barrier. In this study, we developed phage and human platelet lysate (h-PL) incorporated cetomacrogol-based creams for combined phage therapy and wound healing. The base material for phage immobilization was formulated by emulsifying paraffin and sterile water with cetomacrogol (emulsifying agent). Specifically, we incorporated a Pseudomonas aeruginosa-infecting lytic phage vB_PaeM_M12PA in the formulation and characterized its genome in this study. Cetomacrogol, a nonionic PEG (polyethylene glycol) based ether, rendered phage stability and allowed initial burst release followed by continuous controlled release of phages from the embedding matrix in the initial 6-8 h. Rheological studies showed that the material has elastic properties with storage moduli (G') values ranging from 109.51 ± 2.10 to 126.02 ± 3.13 kPa, indicating frequency-independent deformation. Platelet lysates in the cream acted as wound healing agents, and in vitro evaluation of cell migration and wound healing capacity of h-PL showed a significant enhancement by the sixth hour compared to untreated groups. The phage-incorporated cream showed sustained phage release in solid media and a significant reduction in bacterial growth in liquid cultures. In vivo wound healing studies in 6-week-old Wistar rats with full-thickness excision wounds and subsequent histopathological studies showed that the formulation enhanced wound healing and tissue restoration efficiency. In conclusion, the study unveils a promising approach for integrated phage therapy and wound healing strategies.

Regulation of anti-phage defense mechanisms by using cinnamaldehyde as a quorum sensing inhibitor.

Multidrug-resistant bacteria and the shortage of new antibiotics constitute a serious health problem. This problem has led to increased interest in the use of bacteriophages, which have great potential as antimicrobial agents but also carry the risk of inducing resistance. The objective of the present study was to minimize the development of phage resistance in Klebsiella pneumoniae strains by inhibiting quorum sensing (QS) and thus demonstrate the role of QS in regulating defense mechanisms. Cinnamaldehyde (CAD) was added to K. pneumoniae cultures to inhibit QS and thus demonstrate the role of the signaling system in regulating the anti-phage defense mechanism. The QS inhibitory activity of CAD in K. pneumoniae was confirmed by a reduction in the quantitative expression of the lsrB gene (AI-2 pathway) and by proteomic analysis. The infection assays showed that the phage was able to infect a previously resistant K. pneumoniae strain in the cultures to which CAD was added. The results were confirmed using proteomic analysis. Thus, anti-phage defense-related proteins from different systems, such as cyclic oligonucleotide-based bacterial anti-phage signaling systems (CBASS), restriction-modification (R-M) systems, clustered regularly interspaced short palindromic repeat-Cas (CRISPR-Cas) system, and bacteriophage control infection (BCI), were present in the cultures with phage but not in the cultures with phage and CAD. When the QS and anti-phage defense systems were inhibited by the combined treatment, proteins related to phage infection and proliferation, such as the tail fiber protein, the cell division protein DamX, and the outer membrane channel protein TolC, were detected. Inhibition of QS reduces phage resistance in K. pneumoniae, resulting in the infection of a previously resistant strain by phage, with a significant increase in phage proliferation and a significant reduction in bacterial growth. QS inhibitors could be considered for therapeutic application by including them in phage cocktails or in phage-antibiotic combinations to enhance synergistic effects and reduce the emergence of antimicrobial resistance.

Improving osseointegration and antimicrobial properties of titanium implants with black phosphorus nanosheets-hydroxyapatite composite coatings for vascularized bone regeneration.

For decades, titanium implants have shown impressive advantages in bone repair. However, the preparation of implants with excellent antimicrobial properties as well as better osseointegration ability remains difficult for clinical application. In this study, black phosphorus nanosheets (BPNSs) were doped into hydroxyapatite (HA) coatings using electrophoretic deposition. The coatings' surface morphology, roughness, water contact angle, photothermal properties, and antibacterial properties were investigated. The BP/HA coating exhibited a surface roughness of 59.1 nm, providing an ideal substrate for cell attachment and growth. The water contact angle on the BP/HA coating was measured to be approximately 8.55°, indicating its hydrophilic nature. The BPNSs demonstrated efficient photothermal conversion, with a temperature increase of 42.2°C under laser irradiation. The BP/HA composite coating exhibited a significant reduction in bacterial growth, with inhibition rates of 95.6% and 96.1% against Staphylococcus aureus and Escherichia coli. In addition, the cytocompatibility of the composite coating was evaluated by cell adhesion, CCK8 and AM/PI staining; the effect of the composite coating in promoting angiogenesis was assessed by scratch assay, transwell assay, and protein blotting; and the osteoinductivity of the composite coating was evaluated by alkaline phosphatase assay, alizarin red staining, and Western blot. The results showed that the BP/HA composite coating exhibited superior performance in promoting biological functions such as cell proliferation and adhesion, antibacterial activity, osteogenic differentiation, and angiogenesis, and had potential applications in vascularized bone regeneration.

Biocidal Verification Program for Healthcare Facilities: Evaluation of the Efficacy and Microbial Tolerance of Disinfectants

Context: The disinfection of healthcare facilities is of utmost importance to prevent the spread of infectious diseases. In this regard, biocidal activity testing is used to evaluate the efficacy of disinfectants in hospitals. Aim: Establishing a disinfectant efficacy test aimed at combating infections and cross-contamination. Settings and Design: The experiment was carried out in two treatment groups for each of the four microorganisms on ten surface coupons, with a viability control group determined as the baseline inoculum. Methods and Materials: The study used two disinfectants—hydroxyethane (ethylene hydrate) and 2-hydroxypropane (sec-propyl alcohol)—to evaluate their efficacy in reducing bacterial contamination on inanimate surfaces. Statistical analysis used: The data obtained was analyzed using Minitab software, which involved a normal probability plot, a homogeneity of variances test, and a test for equal variances. The statistical significance level was set at α = 0.05. Results: The normal probability plot of microorganism-disinfectant groups with a 95% confidence interval showed improvement in normalization after the logarithmic transformation of datasets. The homogeneity of variances test did not reveal any statistically significant differences between the groups, and all the comparison intervals overlapped for the logarithmically transformed datasets in contrast to the raw datasets. The bacterial reduction after exposure to disinfectants for five minutes compared with the control group in the surface challenge biocidal test expressed as absolute and logarithmic reduction showed a significant reduction in bacterial growth, with Burkholderia cepacia showing greater persistence on the examined sample of the surfaces. Conclusions: The current study showed that the effect of the microorganism tolerance contributed to the variation in responses rather than the disinfectant or the surface types, suggesting the risk of resistant bacteria on the contaminated surface in the dissemination of infections. Thus, monitoring and routine disinfection validation programs for the control of microbial burden in healthcare are crucial for infection and contamination mitigation

Silver nanoparticles (Ag-NPs) embedded in zeolite framework: A comprehensive study on bromide removal from water, including characterization, antibacterial properties, and adsorption mechanisms

In this comprehensive study, a novel adsorbent material comprising silver nanoparticles (Ag-NPs) zeolite composite was synthesized and characterized for its efficacy in removing bromide ions from water. Fourier Transform Infrared Spectroscopy (FT-IR) and X-ray Diffraction (XRD) analyses confirmed the successful integration of Ag-NPs within the zeolite framework, ensuring structural integrity and chemical composition. Under varying operational conditions, the batch experiments consistently exhibited the zeolite with Ag-NPs as superior in bromide removal efficacy compared to zeolite alone, both achieving over 96% removal efficiency. Moreover, the adsorption kinetics aligned well with a second-order reaction model. Furthermore, column studies revealed that zeolite with Ag-NPs performed better than zeolite in maintaining efficient bromide removal over extended durations, highlighting its long-term operational potential. Thermodynamic investigations indicated the exothermic and spontaneous nature of the bromide ion adsorption process, supported by negative ΔG° values. Across temperatures ranging from 22 to 52 °C, the ΔG° values were observed to range from − 1.275 to − 0.049 kJ/mol for bromide removal using zeolite and − 1.90 to − 0.909 kJ/mol for zeolite+Ag-NPs, indicating their favorable adsorption characteristics. Furthermore, the study revealed the remarkable antimicrobial properties of the zeolite with Ag-NPs, as evidenced by a significant reduction in bacterial growth compared to pure zeolite, suggesting its dual application potential for both bromide removal and water disinfection. In conclusion, the integration of Ag-NPs into zeolite represents a promising potential for sustainable and multifunctional water treatment solutions.

Boosting Copper Biocidal Activity by Silver Decoration and Few-Layer Graphene in Coatings on Textile Fibers.

The outbreak of the Coronavirus disease 2019 (COVID-19) pandemic has highlighted the importance of developing antiviral surface coatings that are capable of repelling pathogens and neutralizing them through self-sanitizing properties. In this study, a novel coating design based on few-layer graphene (FLG) is proposed and silver-decorated micro copper flakes (CuMF) that exhibit both antibacterial and antiviral properties. The role of sacrificial anode surfaces and intrinsic graphene defects in enhancing the release of metal ions from CuMF embedded in water-based binders is investigated. In silico analysis is conducted to better understand the molecular interactions of pathogen-repelling species with bacterial or bacteriophage proteins. The results show that the optimal amount of CuMF/FLG in the coating leads to a significant reduction in bacterial growth, with reductions of 3.17 and 9.81 log for Staphylococcus aureus and Escherichia coli, respectively. The same coating also showed high antiviral efficacy, reducing bacteriophage phi6 by 5.53 log. The antiviral efficiency of the coating is find to be doubled compared to either micro copper flakes or few-layer graphene alone. This novel coating design is versatile and can be applied to various substrates, such as personal protective clothing and face masks, to provide biocidal activity against both bacterial and viral pathogens.

Listeria monocytogenes GshF contributes to oxidative stress tolerance via regulation of the phosphoenolpyruvate-carbohydrate phosphotransferase system.

Glutathione (GSH) is an essential component of the glutaredoxin (Grx) system, and it is synthesized by the enzyme glutathione synthase GshF in Listeria monocytogenes. GSH plays a crucial role in regulating Listeria virulence by modifying the virulence factors LLO and PrfA. In this study, we investigated the involvement of L. monocytogenes GshF in oxidative tolerance and intracellular infection. Our findings revealed that the deletion of gshF resulted in a significant reduction in bacterial growth in vitro when exposed to diamide and copper ions stress. More importantly, this deletion also impaired the efficiency of invasion and proliferation in macrophages and mice organs. Furthermore, GshF influenced global transcriptional profiles, including carbohydrate and amino acid metabolism, particularly those related to the phosphoenolpyruvate-carbohydrate phosphotransferase system (PTS) genes lmo1997-lmo2004, under oxidative stress conditions. In the wild-type strain, the transcription of lmo1997-lmo2004 was notably downregulated in response to copper ions and diamide stress compared to normal conditions. However, in the absence of gshF, the transcripts of lmo1997-lmo2004 were upregulated in response to these stress conditions. Notably, the deletion of iiBman (lmo2002) enhanced oxidative stress tolerance to copper ions, whereas overexpression of iiBman reduced this resistance. In conclusion, our study provides the first evidence that L. monocytogenes GshF plays a crucial role in bacterial antioxidation through the regulation of iiBman.IMPORTANCEListeria monocytogenes has developed various mechanisms to withstand oxidative stress, including the thioredoxin and glutaredoxin systems. However, the specific role of the glutathione synthase GshF, responsible for synthesizing GSH in L. monocytogenes, in oxidative tolerance remains unclear. This study aimed to elucidate the relationship between GshF and oxidative tolerance in L. monocytogenes by examining the efficiency of invasion and proliferation in macrophages and mice organs, as well as analyzing global transcriptional profiles under oxidative stress conditions. The results revealed that GshF plays a significant role in L. monocytogenes' response to oxidative stress. Notably, GshF acts to suppress the transcription of phosphoenolpyruvate-carbohydrate phosphotransferase system genes lmo1997-lmo2004, among which iiBman (lmo2002) was identified as the most critical gene for resisting oxidative stress. These findings enhance our understanding of how L. monocytogenes adapts to its environment and provide valuable insights for investigating the environmental adaptation mechanisms of other pathogenic bacteria.

Controlled Nano Cu precipitation through age treatment: a method to enhance the biodegradation, mechanical, antimicrobial properties and biocompatibility of Fe-20Mn-3Cu alloys.

Iron-manganese (Fe-Mn) based degradable biomaterials have been proven as a suitable substitute to permanent internal fracture-fixation devices. However, lower degradation and bacterial infection are still major concerns. To overcome these limitations, in this work, we have incorporated copper (Cu) in Fe-Mn system. The objective is to produce Cu nano-precipitates and refined microstructure through suitable combination of cold-rolling and age-treatment, so that degradation is improved eventually. High resolution transmission electron microscope (TEM) and scanning transmission electron microscope (STEM) confirmed the Cu rich composition of the nano-precipitates. Number of precipitates increased as aging time increased. Three-dimensional visualization of Fe, Mn and Cu atomic distributions using atom probe tomography (APT), indicated that Cu precipitates were in 15-50 nm range. Large number of nano-precipitates along with lower dislocation density led to highest strength (1078 MPa) and ductility (37 %) for the 6-hr age-treated sample. On the other hand, nano-precipitates and refined microstructure resulted highest degradation for the 12 hr of age treated sample (0.091 mmpy). When E.Coli bacteria was cultured with the sample extract, significantly higher antibacterial efficacy was observed for the sample having higher nano-precipitates. Higher degradation rate did not cause cyto-toxicity, rather promoted statistically higher cell proliferation (1.5 times within 24 hr) in in vitro cell-material interaction studies. In vivo biocompatibility of the alloy containing large nano-precipitates was confirmed from higher new bone regeneration (60%) in rabbit femur model. Overall study suggested that the optimization of the thermo-mechanical processes can effectively tailor the Fe-Mn-Cu alloys for successful internal fracture fixation. STATEMENT OF SIGNIFICANCE: : In the present work, we have reported a noble thermo-mechanical approach to simultaneously achieve Cu nano-precipitates and grain refinement in Fe-20Mn-3Cu alloy. Significant reduction in bacterial growth was observed in the sample containing high Cu precipitation. This is extremely significant in the present context. Cu nano-precipitates and grain refinement improved the degradation rate. Highest yield strength was observed after 12 hours of age treatment (493 MPa). We have theoretically calculated various factors of yield strength. High degradation rate did not cause cytotoxicity, rather promoted cell viability. We have reported that the released Cu ion concentration in vivo was not only below toxic limit, but also helped in new bone regeneration.

Personal stethoscope disinfection practices and bacterial contamination: A cross-sectional study at the University Hospital Emergency Department in Belgrade, Serbia

A significant reduction in bacterial growth on stethoscope membranes has been noticed after performing daily disinfection. Nevertheless, disinfection is rarely performed. We aimed to assess self-reported stethoscope disinfection practices among medical doctors, detect bacterial contamination on personal stethoscopes, and estimate the effectiveness of 70% ethanol as a stethoscope disinfecting agent. To determine stethoscope disinfection practices, participants filled out a questionnaire (N=47), followed by providing stethoscopes for bacterial analysis. Differences in bacterial contamination were observed through the self-reported frequency and method of stethoscope disinfection. The effect of disinfecting with 70% ethanol was evaluated by comparing the presence of bacterial growth before and after disinfection. The presence of bacterial growth was found in 78.7% of the stethoscope samples, with the median (interquartile range) number of colony-forming units at 25 (10-105). The frequency of disinfection greatly impacted the number of colony-forming units, and the method affected the presence of bacterial growth. Disinfection of stethoscope membranes using 70% ethanol resulted in a compelling 97.3% reduction of bacterial growth. Adequate stethoscope disinfection is highly efficient in reducing bacterial contamination and as such should be considered a critical step in hygienic practices.

Nanodevices based on mesoporous glass nanoparticles enhanced with zinc and curcumin to fight infection and regenerate bone.

Nanotechnology-based approaches are emerging as promising strategies to treat different bone pathologies such as infection, osteoporosis or cancer. To this end, several types of nanoparticles are being investigated, including those based on mesoporous bioactive glasses (MGN) which exhibit exceptional structural and textural properties and whose biological behaviour can be improved by including therapeutic ions in their composition and loading them with biologically active substances. In this study, the bone regeneration capacity and antibacterial properties of MGNs in the SiO2-CaO-P2O5 system were evaluated before and after being supplemented with 2.5% or 4% ZnO and loaded with curcumin. in vitro studies with preosteoblastic cells and mesenchymal stem cells allowed determining the biocompatible MGNs concentrations range. Moreover, the bactericidal effect of MGNs with zinc and curcumin against S. aureus was demonstrated, as a significant reduction of bacterial growth was detected in both planktonic and sessile states and the degradation of a pre-formed bacterial biofilm in the presence of the nanoparticles also occurred. Finally, MC3T3-E1 preosteoblastic cells and S. aureus were co-cultured to investigate competitive colonisation between bacteria and cells in the presence of the MGNs. Preferential colonisation and survival of osteoblasts and effective inhibition of both bacterial adhesion and biofilm formation of S. aureus in the co-culture system were detected. Our study demonstrated the synergistic antibacterial effect of zinc ions combined with curcumin and the enhancement of the bone regeneration characteristics of MGNs containing zinc and curcumin to obtain systems capable of simultaneously promoting bone regeneration and controlling infection. STATEMENT OF SIGNIFICANCE: In search of a new approach to regenerate bone and fight infections, a nanodevice based on mesoporous SiO2-CaO-P2O5 glass nanoparticles enriched with Zn2+ ions and loaded with curcumin was designed. This study demonstrates the synergistic effect of the simultaneous presence of zinc ions and curcumin in the nanoparticles that significantly reduces the bacterial growth in planktonic state and is capable to degrade pre-formed S. aureus biofilms whereas the nanosystem exhibits a cytocompatible behaviour in the presence of preosteoblasts and mesenchymal stem cells. Based on these results, the designed nanocarrier represents a promising alternative for the treatment of acute and chronic infections in bone tissues, while avoiding the significant current problem of bacterial resistance to antibiotics.

#5863 A NOVEL SELF-SEALING DIALYSIS PORT EVALUATION

Abstract Background and Aims There are several complications associated with hemodialytic vascular that arise from the incorrect cannulation, including aneurysms, infection, vessel damage, and uncontrolled bleeding. These risks severely limit treatment opportunities for self-cannulation by patients, which is necessary step for home hemodialysis. To improve quality of life and reduce complications, we developed a novel access port, called Safe Entry Port for AV fistuLae (SEAL), that integrates with fistulae, guides cannulation, and uses an internal colinear valve to prevent aneurysms with minimal risk of back-bleeding and infections (Figure 1A-C). Method The device was additively manufactured using direct metal laser sintering of FDA-approved Ti-6Al-4V. It was then polished and coated with silver-doped titanium nitride (TiN/Ag). The operation of the valve was tested in a mock circulation system using a peristaltic pump and Tyvek tubing to produce a pulsatile hydrostatic pressure gradient. The antimicrobial properties of the valve coating were evaluated in vitro against biofilm formation using standard assays for bacterial spreading area and turbidity. A custom computer-controlled robotic cannulation system was created to fatigue test the port as well as to determine the needle force required to open the valve. Finally, the device was implanted subdermally on a mature brachiocephalic arteriovenous fistula of an adult sheep and cannulated biweekly for six weeks. Device integration and host tissue reaction were evaluated using standard histopathological methods and micro-CT scanning. Results SEAL is engineered to integrate directly over a fistula via a Ti matrix (a mesh of small holes covering the sides of the device for interaction with host tissue). No fluid leaked through the valve during in vitro testing even under physiologically high circulatory pressure. In repeated cannulations of the device during ex vivo simulations with 14G dialysis needles, the peak force required to engage the valve recorded in our dialysis fatigue cycling simulation was 160.5 $ \pm $ 0.02 mN (Figure 1D, E). The device withstood cannulation cycles equivalent to 14 years of dialysis. Furthermore, the colinear valve smoothly opened for continuous flow through the needle guide (Figure 1F-I) and closed automatically under the tensile force similar to that of subcutaneous tissue. Antimicrobial TiN/Ag coating showed significant reduction in bacterial growth in both biofilm assays (Figure 1J,K). In preclinical trials, no signs of infection or backbleeding were observed during the continuous six-week cannulation period; vascular access was continuous with no resistance or complications. Conclusion We show that SEAL nearly eliminates backbleeding risk both in vitro and in vivo. The TiN/Ag coating of the colinear valve significantly limits bacterial biofilm formation ex vivo. Preclinical studies in the sheep model show that the device implanted on a mature fistula can easily be cannulated twice a week without any infection, cannulation complications, or backbleeding for an extensive period. SEAL has the potential to change the future of dialysis treatments, improve the quality of life for patients due the reduction of complications, and allow improved access to home hemodialysis.

Discerning the role of polymyxin B nonapeptide in restoring the antibacterial activity of azithromycin against antibiotic-resistant Escherichia coli.

Antimicrobial resistance is a global public health threat. Antibiotic development pipeline has few new drugs; therefore, using antibiotic adjuvants has been envisioned as a successful method to preserve existing medications to fight multidrug-resistant (MDR) pathogens. In this study, we investigated the synergistic effect of a polymyxin derivative known as polymyxin B nonapeptide (PMBN) with azithromycin (AZT). A total of 54 Escherichia coli strains were first characterized for macrolide resistance genes, and susceptibility to different antibiotics, including AZT. A subset of 24 strains was then selected for synergy testing by the checkerboard assay. PMBN was able to re-sensitize the bacteria to AZT, even in strains with high minimum inhibitory concentrations (MIC: 32 to ≥128 μg/ml) for AZT, and in strains resistant to the last resort drugs such as colistin and meropenem. The fractional inhibitory concentration index was lower than 0.5, demonstrating that PMBN and AZT combinations had a synergistic effect. The combinations worked efficiently in strains carrying mphA gene encoding macrolide phosphotransferase which can cause macrolide inactivation. However, the combinations were inactive in strains having an additional ermB gene encoding macrolide methylase which causes ribosomal drug target alteration. Killing kinetics study showed a significant reduction of bacterial growth after 6 h of treatment with complete killing achieved after 24 h. Transmission electron microscopy showed morphological alterations in the bacteria treated with PMBN alone or in combination with AZT, with evidence of damage to the outer membrane. These results suggested that PMBN acted by increasing the permeability of bacterial outer membrane to AZT, which was also evident using a fluorometric assay. Using multiple antimicrobial agents could therefore be a promising strategy in the eradication of MDR bacteria. PMBN is a good candidate for use with other antibiotics to potentiate their activity, but further studies are required in vivo. This will significantly contribute to resolving antimicrobial resistance crisis.

Efficiency of Pyroligneous Extract from Jurema Preta (Mimosa tenuiflora [Willd.] Poiret) as an Antiseptic in Cats (Felis catus) Subjected to Ovariosalpingohysterectomy.

Simple SummaryThe pyroligneous extract from Mimosa tenuiflora was used as an antiseptic in cats. The objective of this study was to analyze the action of 20% pyroligneous extract from M. tenuiflora as an antiseptic for surgical wounds of cats subjected to ovariohysterectomy. In addition to the absence of cytotoxicity, the number of bacteria was reduced after treatment. Tissue dehiscence, hyperemia, edema, crust, and secretions were not observed. Thus, the pyroligneous extract of M. tenuiflora has potential as a natural antiseptic alternative.Pyroligneous extract of Jurema preta (Mimosa tenuiflora [Willd.] Poiret) was evaluated for its efficacy as a cutaneous antiseptic in cats (Felis catus) that were subjected to ovariosalpingohysterectomy. For this purpose, 30 cats without a defined breed were sterilized and divided into two groups. The first group was the positive control, treated with 0.5% chlorhexidine-alcohol solution, and the second group was treated with 20% pyroligneous extract of M. tenuiflora. Regardless of age and sex, all animals had visible healing at similar times. A significant reduction in bacterial growth was observed in animals treated with the extract, and no cytotoxicity was observed in the feline epithelial cells. In addition, surgical wounds of cats treated with M. tenuiflora extract exhibited improved healing. On agar plates, treatment with both chlorhexidine and M. tenuiflora extract resulted in the inhibition zones for all bacterial strains isolated from surgical wounds. Therefore, M. tenuiflora extract is demonstrated to have antiseptic effects on the surgical wounds of cats undergoing ovariosalpingohysterectomy.

Biofilm inhibition and bacterial eradication by C-dots derived from polyethyleneimine-citric acid

Protonable polyethyleneimine (PEI) and citric acid (CA) based C-dots were prepared via a hydrothermal process, yielding particles with a hydrodynamic diameter of ~100 and ~80 nm, and zeta potential of − 2.3 ± 0.1 and + 23.4 ± 0.2 mV for PEI-CA C-dots and their protonated form, respectively. Treating Staphylococcus aureus with these C-dots resulted in a statistically significant reduction in bacterial growth, specifically growth in the planktonic phase as well as in the development of bacterial biofilm when compared to untreated (p < 0.05). When 24 h matured S. aureus biofilms were treated with C-dots, a significant disruption and dispersion of bacteria from the existing biofilms was noted as compared to untreated (p < 0.05). Other Gram-positive microorganisms (B. cereus, S. epidermidis, S. pyogenes) and Gram-negative (P. mirabilis, E. coli, and P. aeruginosa) were also susceptible to the antimicrobial activity of the PEI-CA C-dots with significant inhibition of bacterial growth noted for all organisms after C-dot treatment. Only for B. cereus, S. epidermidis, and P. aeruginosa was this reduction in total growth reflected in decreased planktonic growth. However, biofilm formation by all organisms was reduced significantly upon treatment with the C-dots, including those for which planktonic growth was not impacted.

Bactericidal effect of hyperbaric oxygen therapy in burn injuries

IntroductionBurn injuries are frequently encountered in emergency cases and often become the port of entry for pathogens. More than 450,000 burn injuries occur annually causing nearly 3,400 deaths in the United States. The prevalence of burn injury in Indonesia is 0.7% in 2013. More than half of these According to several studies on the use of patients were treated for bacterial infections, some of which were resistant to certain antibiotics. Using hyperbaric oxygen therapy (HBOT) to treat burns has several positive effects including managing bacterial infections, as well as accelerating the wound healing process. Therefore, this study aims to prove the effectiveness of HBOT in inhibiting bacterial growth. MethodsThis is an experimental research study in rabbits using a post-test control group design. 38 rabbits were given second-degree burns on the shoulder region with a metal iron plate that has been previously heated for 3 min. Bacterial cultures were taken on days 5 and 10 after exposure to the burns. The samples were divided into two groups, HBOT and control. Statistical analyses were performed using the Mann-Whitney U method. ResultsGram-negative bacteria were the most frequently found pathogen in both groups. Citrobacter freundi was the most common Gram-negative bacteria (34%) found in the culture results of both groups.In contrast to the control group, there was no bacterial growth found in the HBOT group's culture results, (0%) vs (58%). A significant reduction of bacterial growth was observed in the HBOT group (69%) compared with the control group (5%). Bacterial levels stagnated in 6 rabbits (31%) in the HBOT group and 7 rabbits (37%) in the control group. Overall, there was significantly less bacterial growth in the HBOT treatment group compared with the control group (p < 0.001). ConclusionHBOT administration can significantly reduce bacterial growth in burn injuries.

Effect of Plant Age, Temperature, and Vector Load on 'Candidatus Liberibacter solanacearum' in Planta Titer and Shoot Proliferation Symptoms in Carrot.

A decade ago, shoot proliferation symptoms (i.e., witches' broom) in carrots were believed to be the cause of 'Candidatus Phytoplasma' and Spiroplasma infection, yet in recent years this association appeared to have weakened, and a closer association was found with the yet-unculturable, psyllid-transmitted Gram-negative bacterium 'Candidatus Liberibacter solanacearum'. In Israel, carrots are grown throughout the year, yet shoot proliferation symptoms tend to appear only in mature plants and mostly in late spring to early summer. We hypothesized that factors such as plant age, temperature, and vector load, which vary during the year, have a critical effect on symptom development and examined these factors under controlled conditions. Here we show that young carrot seedlings are as prone as older plants to develop shoot proliferation symptoms after 'Ca. L. solanacearum' inoculation. Surprisingly, we found that the local 'Ca. L. solanacearum' haplotype was extremely sensitive to constant temperature of 30°C, which led to a significant reduction in bacterial growth and symptom development compared with 18°C, which was very conducive to symptom development. We have also found that inoculations with 10 or 20 psyllids per plant results in faster symptom development compared with inoculations with two psyllids per plant; however, the difference between vector loads in disease progress rate was not significant. These data provide important insights to the effects of plant age, growth temperature, and vector load on 'Ca. L. solanacearum' and its associated symptoms and further strengthen the notion that 'Ca. L. solanacearum' is the main responsible agent for carrot witches' broom in Israel.[Formula: see text] Copyright © 2022 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.

Role of aspartate ammonia-lyase in Pasteurella multocida

BackgroundPasteurella multocida is responsible for a highly infectious and contagious disease in birds, leading to heavy economic losses in the chicken industry. However, the pathogenesis of this disease is poorly understood. We recently identified an aspartate ammonia-lyase (aspA) in P. multocida that was significantly upregulated under iron-restricted conditions, the protein of which could effectively protect chicken flocks against P. multocida. However, the functions of this gene remain unclear. In the present study, we constructed aspA mutant strain △aspA::kan and complementary strain C△aspA::kan to investigate the function of aspA in detail.ResultDeletion of the aspA gene in P. multocida resulted in a significant reduction in bacterial growth in LB (Luria-Bertani) and MH (Mueller-Hinton) media, which was rescued by supplementation with 20 mM fumarate. The mutant strain △aspA::kan showed significantly growth defects in anaerobic conditions and acid medium, compared with the wild-type strain. Moreover, growth of △aspA::kan was more seriously impaired than that of the wild-type strain under iron-restricted conditions, and this growth recovered after supplementation with iron ions. AspA transcription was negatively regulated by iron conditions, as demonstrated by quantitative reverse transcription-polymerase chain reaction. Although competitive index assay showed the wild-type strain outcompetes the aspA mutant strain and △aspA::kan was significantly more efficient at producing biofilms than the wild-type strain, there was no significant difference in virulence between the mutant and the wild-type strains.ConclusionThese results demonstrate that aspA is required for bacterial growth in complex medium, and under anaerobic, acid, and iron-limited conditions.

Spondias mombin L. decoction utilization as antiseptic in cats submitted to castration

This survey evaluated mombin leaves (Spondias mombin L.) decoction efficiency as an antiseptic during post-surgery period on cats submitted to orchiectomy and ovariosalpingohisterectomy. For this purpose, 45 castrated mongrels cats were divided into three groups, the first group as a positive control using 0.5% chlorhexidine-alcohol solution, the second a negative control group using sterile distilled water and, finally, the test group using mombin leaves decocted with a concentration of 100 mg/mL. All animals, independent of age and sex, had visibly healed in most cases in a similar time. Animals treated with mombin leaves decoction presented a significant reduction of bacterial growth. In addition, the animals treated in the test group had better surgical wound healing. All isolated bacterial strains presented inhibition halo for chlorhexidine and for Spondias mombin L. Thus, the decoction of Spondias mombin L. leaves proved antiseptic efficacy in the surgical wounds of cats submitted to orchiectomy and ovariosalpingohisterectomy.

Co-administration of Erythromycin and Leech Salivary Extract Alleviates Osteomyelitis in Rats Induced by Methicillin-Resistant Staphylococcus aureus.

Erythromycin (Ery) and leech saliva (LS) can inhibit Staphylococcus aureus growth in in vitro conditions. This study aimed to evaluate the activities and synergy between Ery and LS on chronic osteomyelitis in male Wistar rat's tibia induced by methicillin-resistant S. aureus (MRSA). Four weeks after osteomyelitis induction, rats were divided into four groups including no treatment (control), Ery monotherapy (orally), LS monotherapy, or Ery + LS twice daily for 2 weeks. Staphylococcus aureus growth, pathological signs and inflammatory cytokine tumour necrosis factor-alpha (TNF-α) levels were assessed. Rats tolerated all therapeutic strategies well during the experiment. The Ery treatment alone significantly decreased bacterial growth, pathological signs and TNF-α levels. Leech saliva alone reduced TNF-α level significantly, but did not produce a significant reduction in bacterial growth and pathological signs. Ery + LS treatment significantly decreased bacterial growth, considerably alleviated bone pathological signs and decreased TNF-α levels compared with other groups. Statistical analysis suggested that there was a stronger efficiency and synergistic action of Ery and LS when combined against MRSA-induced osteomyelitis in rats. The present study suggests that LS may have clinical utility to treat MRSA-induced osteomyelitis when combined with Ery or other therapeutics.