Pathogen characteristics and its sensitivity against antimicrobial agents in fatal bacterial granuloma after eyelid trauma in vitro

AIM: To understand the pathogen characteristics and its sensitivity against antimicrobial agents in fatal bacterial granuloma after eyelid trauma (FBGT) in vitro, and to provide laboratory evidence for diagnosis. METHODS: The FBGT pathogens were isolaated and cultured with reformed rabbit-brain anaerobic enriched broth (RRAB), and identified by ATB/API 20A system. The minimum inhibiting concentration (MIC) was determined by anaerobic broth dilution method. RESULTS: A total of 22 strains of pathogen were separated from 21 patients with FBGT and identified as Propionibacterium acnes (PA) by ATB/API 20A system. The MIC of ciprofloxacin for 22 PA strains was 0.0625-0.5mg/L, the MIC of penicillin, ampicillin, ampicillin/sulbactam, cefoperazone, lincomycin, and imipenem/cilastatin were 0.125-0.5mg/L, the MIC of ticarcillin/clavulanic acid was 0.250-1.000mg/L, and the MIC of metronidazole was 64-256mg/L. The pathogen of FBGT was strictly anaerobic PA, which growed slowly and better in nutritious RRAB broth. All PA were resistant to metronidazole, but susceptive to other routine antimicrobial agents, such as penicillin, ampicillin and lincomycin. CONCLUSION: FBGT should not be treated with metronidazole. Clinicians should choose combined use of drugs or operation to treat FBGT according to patients' individual condition and the results of drug sensitivity test.

Evaluation of rational use of antimicrobial agents in a Brazilian intensive care unit

The present study sought to assess the rational use of antimicrobial agents in a Brazilian intensive care unit (ICU) and its association with antimicrobial resistance in elderly patients admitted to the unit. Results: Choice of empiric and sensitivity-guided therapy was inadequate in > 80% and 59% of cases respectively. Inadequate antimicrobial therapy, whether empiric or sensitivity-guided, was positively correlated with bacterial resistance (r = 0.316;p = 0.001). Sensitivity testing revealed a 46.5% resistance rate to eight out of the ten most commonly used antibiotics. Multiple drug-resistant organisms were found in 40.8% of patients. A significant increase was observed in the number of multidrug-resistant samples between 2006/2007 and 2008 (r = 0.41, p = 0.006), (r = 0.598, p = 0.001), (r = 0.688, p = 0.00). Conclusion: We found a high rate of antibiotic misuse in the study sample. Inadequate therapy was correlated with resistance to antimicrobial agents.

Susceptibility of Mixed Infection of Ureaplasma Urealyticum and Mycoplasma Hominis to Seven Antimicrobial Agents and Comparison with that of Ureaplasma Urealyticum Infection

In order to investigate the susceptibility of mixed infection of Ureaplasma Urealyticum (UU) and Mycoplasma Hominis (MH) to 7 kinds of antimicrobial agents and comparison with that of UU infection in NGU patients, the in vitro susceptibility was determined by using microdilution method. The positive results were analyzed. The results showed that the sequence of susceptibility to 7 kinds of antimicrobial agents for both UU infection group and UU-MH mixed infection group was almost the same from the highest susceptibility to the lowest accordingly: Josamycin, Doxycycline, Minocycline, Sparfloxacin, Roxithromycin, Ofloxacin and Azithromycin. The total drug resistance rate for UU-MH mixed infection group (97. 67 %) was significantly higher than that for UU infection group (44. 67 %, P<.0. 01). The highest drug resistance rate in UU group and UU-MH mixed infection group was 31. 33 % (Ofloxacin) and 90. 48 % (Azithromycin) respectively. UU-MH mixed infection showed an increased drug resistance and changes of drug resistance spectrum.

Optimization of four types of antimicrobial agents to increase the inhibitory ability of marine Arthrobacter oxydans KQ 11 dextranase mouthwash

We adopted the response surface methodology using single factor and orthogonal experiments to optimize four types of antimicrobial agents that could inhibit biofilm formation by Streptococcus mutans, which is commonly found in the human oral cavity and causes tooth decay. The objective was to improve the function of marine Arthrobacter oxydans KQll dextranase mouthwash （designed and developed by our laboratory）. The experiment was conducted in a three-level, four-variable central composite design to determine the best combination of ZnSO4, lysozyme, citric acid and chitosan. The optimized antibacterial agents were 2.16 g/L ZnSO4, 14 g/L lysozyme, 4.5 g/L citric acid and 5 g/L chitosan. The biofilm formation inhibition reached 84.49%. In addition, microscopic observation of the biofilm was performed using scanning electron microscopy and confocal laser scanning microscopy. The optimized formula was tested in marine dextranase Arthrobacter oxydans KQ11 mouthwash and enhanced the inhibition of S. mutans. This work may be promoted for the design and development of future marine dextranase oral care products.

The Antimicrobial Activity of Wool Fabrics Treated with Crosslinking Agents and Polyhexamethylene Biguanide

In this study,we used citric acid(CA)as a crosslinking agent,mixed with polyhexamethylene biguanide,to perform a pad-dry-cure treatment on wool fabrics to study its antimicrobial effects and physical properties.

Synthesis and Antimicrobial Properties of the Novel Fluonnated Bis-ammonium Salts with Two Primary Amine Groups

In order to resolve the increasing resistance phenomena of the Gram-negative bacteria against single chain quaternary ammonium salts （QAS）, lysine with a pedant fluorinated bis-ammonium salts was synthesized and its antimicrobial properties were evaluated in this work. The novel fluorinated bis-ammonium salts shows similar activity with conventional single chain quaternary ammonium salts against Gram-positive bacteria but stronger activity against Gram-negative bacteria and yeast compared with the single chained counterpart.

Antimicrobial and Antioxidant Activity of Anacardium occidentale L. Flowers in Comparison to Bark and Leaves Extracts

Anacardium occidentale L., Anacardiaceae, is frequently used to treat infections. We evaluated the antimicrobial and antioxidant activity of extracts obtained from aerial parts of the plant in comparison with the extract prepared with the flowers. Ethanol extracts of the leaves (EEL), stem bark (EEB), and flowers (EEF) were prepared separately. The antimicrobial activity was evaluated by agar diffusion and broth dilution methods. The minimum bactericidal and fungicidal concentrations were determined against: Streptococcus mutans, Lactobacillus acidophilus, Staphylococcus aureus, MRSA, Enterococcus faecalis, Streptococcus pyogenes, Pseudomonas aeruginosa, Proteus mirabilis, Escherichia coli, Klebsiella pneumoniae, Helicobacter pylori, Salmonella choleraesuis, Candida albicans, and Candida tropicalis. The antioxidant activity of the extracts was evaluated based on their scavenger capacity of 2,2-diphenyl-1-picrylhydrazyle. The phytochemical profile was analyzed by colorimetric methods and by HPLC with UV detection. All extracts exhibited antioxidant and antimicrobial activity. Although, the EEF was the most effective since it inhibited the growth of all 14 microorganisms tested. Anacardic and galic acids were identified in all extracts as well phenolic compounds, triterpenes, flavones and xanthones. In conclusion, the extracts obtained from the aerial parts of A. occidentale, mainly the extract of flowers that was the most effective, are rich in bioactive metabolites that exert a potent antioxidant and antimicrobial effect. Taken together, the results indicate an important biotechnological potential of A. occidentale as a source of compounds with broad-spectrum antimicrobial and of antioxidant activity to be used in the food and cosmetics industry.

Structure, properties and application to water-soluble coatings of complex antimicrobial agent Ag-carboxymethyl chitosan-thiabendazole

The structure, properties and application to water-soluble coatings of a new complex antimicrobial agent Ag-carboxylmethyl citosan-thiabendazole （Ag-CMCTS-TBZ） prepared from different materiel ratios were reported. The silver ions were preferably coordinated with the free-NH2 groups and the -OH groups of secondary alcohol and carboxyl in CMCTS. TBZ preferably bonded to carboxyl group in CMCTS by electrostatic force and hydrogen bonding. Increase in silver ions content in the complex agent improved to some limited extent the antibacterial activity, but enhanced coloring and cost of the complex agent. Increase in TBZ content resulted in increase of antifungal activity, but decrease of water solubility of the complex agent. The antimicrobial MICs of the complex agent to Esherichia coil, Staphylococcus aureus, Candida albicans, Aspergillus niger, Mucor sp. were 20 -80, 15 -60, 20 - 55, 40 - 250, and 400 - 1700 mg/kg, respectively. Addition of 0.1% of this complex agent to acrylic emulsion paint made the paint without substantial change in color, luster, viscosity, odor or pH value, but with an excellent and chronically persisting broad-spectra antimicrobial activity.

Effects of water-aging for 6 months on the durability of a novel antimicrobial and protein-repellent dental bonding agent

Biofilms at the tooth-restoration bonded interface can produce acids and cause recurrent caries. Recurrent caries is a primary reason for restoration failures. The objectives of this study were to synthesize a novel bioactive dental bonding agent containing dimethylaminohexadecyl methacrylate(DMAHDM) and 2-methacryloyloxyethyl phosphorylcholine(MPC) to inhibit biofilm formation at the tooth-restoration margin and to investigate the effects of water-aging for 6 months on the dentin bond strength and protein-repellent and antibacterial durability. A protein-repellent agent(MPC) and antibacterial agent(DMAHDM) were added to a Scotchbond multi-purpose(SBMP) primer and adhesive. Specimens were stored in water at 37 °C for 1, 30, 90, or 180 days(d).At the end of each time period, the dentin bond strength and protein-repellent and antibacterial properties were evaluated. Protein attachment onto resin specimens was measured by the micro-bicinchoninic acid approach. A dental plaque microcosm biofilm model was used to test the biofilm response. The SBMP + MPC + DMAHDM group showed no decline in dentin bond strength after water-aging for 6 months, which was significantly higher than that of the control(P < 0.05). The SBMP + MPC + DMAHDM group had protein adhesion that was only 1/20 of that of the SBMP control(P < 0.05). Incorporation of MPC and DMAHDM into SBMP provided a synergistic effect on biofilm reduction. The antibacterial effect and resistance to protein adsorption exhibited no decrease from 1 to 180 d(P > 0.1). In conclusion, a bonding agent with MPC and DMAHDM achieved a durable dentin bond strength and long-term resistance to proteins and oral bacteria. The novel dental bonding agent is promising for applications in preventive and restorative dentistry to reduce biofilm formation at the tooth-restoration margin.

Antimicrobial resistance in clinically important biofilms

A biofilm contains a consortium of cohesive bacterial cells forming a complex structure that is a sedentary, but dynamic, community. Biofilms adhere on biotic and abiotic surfaces, including the surfaces of practically all medical devices. Biofilms are reported to be responsible for approximately 60% of nosocomial infections due to implanted medical devices, such as intravenous catheters, and they also cause other foreign-body infections and chronic infections. The presence of biofilm on a medical device may result in the infection of surrounding tissues and failure of the device, necessitating the removal and replacement ofthe device. Bacteria from biofilms formed on medical devices may be released and disperse, with the potential for the formation of new biofilms in other locations and the development of a systemic infection. Regardless of their location, bacteria in biofilms are tolerant of the activities of the immune system, antimicrobial agents, and antiseptics. Concentrations of antimicrobial agents sufficient to eradicate planktonic cells have no effect on the same microorganism in a biofilm. Depending on the microbial consortium or component of the biofilm that is involved, various combinations of factors have been suggested to explain the recalcitrant nature of biofilms toward killing by antibiotics. In this mini-review, some of the factors contributing to antimicrobial resistance in biofilms are discussed.

Effectiveness of Disinfection in Bacteriology Laboratories in Togo, 2021

Background: Laboratory personnel is at risk of biological contamination leading to laboratory-acquired infections (LAIs). The use of disinfection products is essential in the prevention of these infections. This work aimed to evaluate the effectiveness of antimicrobial agents used in disinfection in bacteriology laboratories in Togo. Methods: This was a cross-sectional study conducted from June to December 2021 in all bacteriology laboratories in Togo. Swabs taken before and after disinfection of surfaces and staff hands were immediately plated on agar media. Counting and identification of isolated colonies were done after 24 hours of incubation. The ANOVA test was used to compare calculated means, prevalence ratio (PR) and 95% confidence intervals (CI) to compare bacterial frequencies. Results: A total of 393 samples were taken, of which 41.2% were from hands. Before disinfection, surfaces were more contaminated than hands with respectively 40.4% and 29.6% (PR = 1.3;CI 95% = [0.9 - 1.9]). After surface disinfection with 0.5% of chlorine solution, bacterial elimination was total, but partial on hands washed with soap, with residual contamination of 3.7%. A total of 108 strains were isolated before disinfection of which Klebsiella spp. 38.9% and Staphylococcus spp. 25.0%;after disinfection 4 strains were isolated of which: Staphylococcus spp. 75.0% and Klebsiella spp. 25.0%. Conclusion: Surface disinfection was more effective than hand washing with soap and water. We recommend proper hand washing.

Treatment of Helicobacter pylori infection:Current status and future concepts

Helicobacter pylori(H.pylori)infection is highly associated with the occurrence of gastrointestinal diseases,including gastric inflammation,peptic ulcer,gastric cancer,and gastric mucosa-associated lymphoid-tissue lymphoma.Although alternative therapies,including phytomedicines and probiotics,have been used to improve eradication,current treatment still relies on a combination of antimicrobial agents,such as amoxicillin,clarithromycin,metronidazole,and levofloxacin,and antisecretory agents,such as proton pump inhibitors(PPIs).A standard triple therapy consisting of a PPI and two antibiotics(clarithromycin and amoxicillin/metronidazole)is widely used as the first-line regimen for treatment of infection,but the increased resistance of H.pylori to clarithromycin and metronidazole has significantly reduced the eradication rate using this therapy and bismuth-containing therapy or 10-d sequential therapy has therefore been proposed to replace standard triple therapy.Alternatively,levofloxacin-based triple therapy can be used as rescue therapy for H.pylori infection after failure of first-line therapy.The increase in resistance to antibiotics,including levofloxacin,may limit the applicability of such regimens.However,since resistance of H.pylori to amoxicillin is generally low,an optimized high dose dual therapy consisting of a PPI and amoxicillin can be an effective first-line or rescue therapy.In addition,the concomitant use of alternative medicine has the potential to provide additive or synergistic effects against H.pylori infection,though its efficacy needs to be verified in clinical studies.

Antibacterial Properties of Novel Bacterial Cellulose Nanofiber Containing Silver Nanoparticles

In this work,we describe a novel facile method to prepare long one-dimensional hybrid nanofibers by using hydrated bacterial cellulose nanofibers(BCF)as a template.Silver(Ag)nanoparticles with an average diameter of 1.5 nm were well dispersed on BCF via a simple in situ chemical-reduction between AgNO3and NaBH4at a relatively low temperature.A growth mechanism is proposed that Ag nanoparticles are uniformly anchored onto BCF by coordination with BC-containing hydroxyl groups.The bare BCF and as-prepared Ag/BCF hybrid nanofibers were characterized by several techniques including transmission electron microscopy,X-ray diffraction,thermogravimetric analyses,and ultraviolet-visible(UV-Vis)absorption spectra.The antibacterial properties of Ag/BCF hybrid nanofibers against Escherichia coli(E.coli,Gram-negative)and Staphylococcu saureus(S.saureus,Gram-positive)bacteria were evaluated by using modified Kirby Bauer method and colony forming count method.The results show that Ag nanoparticles are well dispersed on BCF surface via in situ chemical-reduction.The Ag/BCF hybrid nanofiber presents strong antibacterial property and thus offers its candidature for use as functional antimicrobial agents.

Incidence of Urinary Tract Infections (UTI) amongst Patients Attending Primary Health Centres in Anambra State

Urinary tract infections (UTIs) are one of the most prevalent extra-intestinal bacterial infections. It is a common disease encountered in medical practice affecting people of all ages, from neonate to geriatric age group. These infections are on the increase for outpatients attending Primary Health Centres in Anambra State, Nigeria, therefore the need for this study. The prevalence rate of urinary tract infection, age distribution and influence of sex were determined. Susceptibility pattern of the infectious organisms to antimicrobial agent were examined. Clean-catch midstream urine samples were collected and examined. Out of 3000 urine samples examined, 528 bacterial isolates were recovered and characterized. These include: Escherichia coli (24.2%), Klebsiella spp. (18.2%), Staphylococcus aureus (18.2%), Proteus mirabilis (9.1%), Pseudomonas aeruginosa (9.1%), Enterococcus faecalis (9.1%), Citrobacter intermedius (6.1%) and Staphylococcus saprophyticus (6.1%). More females (52%) were infected than males (48%) and in both sexes, the highest incidence was found amongst the age group, 26 - 38 years. Gram negative rods had the highest incidence in both sexes. Among the towns in Anambra state, Umunya in southern province was observed to have the highest incidence rate of UTI. Susceptibility test of the bacterial isolates to antimicrobial agents showed that Staphylococcus aureus was sensitive to Cephalexin, Penicillin V, Erythromycin and Gentamycin while Pseudomonas aeruginosa was resistant to all the antibiotics. Escherichia coli and Klebsiella spp. were resistant to all the antibiotics except Gentamycin while Citrobacter intermedius was resistant only to Cephalexin and Erythromycin. This study provides the evidence of urinary tract infections amongst outpatients of primary health centres and the drugs for their control.

Analysis of Drug Resistance Spectra and Conjugative Plasmid Carrying Rates of P.aeruginosa and Acinetobacter

Antimicrobial susceptibility test was performed on 57 clinical isolates of P. aeruginosa and 36 clinical isolates of Acinetobacter with 11 antimicrobial agents including getamicin, amikacin, ciprofloxacin, ofloxacin, fleroxacin, piperacillin, cefotaxime, cefoperazone/sulbactam, ceftazidime, cefoperazone and doxycycline. Transferable drug resistance plasmid carrying rates of these clinical isolates were also studied. On the basis of the in vitro activities, 52.63%(30/57) of the isolated strains of P. aeruginosa were susceptible to antimicrobial agents selected (except doxycycline), 41.67%(15/36) of the isolated strains of Acinetobacter were susceptible to 11 antimicrobial agents. The sensitivity rate of P.aeruginosa and Acinetobacter to antimicrobial agents selected was 70% or greater to all except doxycycline. Furthermore, the sensitivity rate of P.aeruginosa to amikacin ciprofloxacin, ceftazidime, cefoperazone, cefoperazone/sulbactam, and that of Acinetobacter to cefoperazone/sulbactam, amikacin was more than 90%,among them amikacin, cefoperazone/sulbactam being the most effective. Plasmid analysis showed that 15.79%(9/57) P.aeruginosa strains and 13.89%(5/36) Acinetobacter strains carried plasmid. Conjugative plasmid carrying rates of P. aeruginosa strains and Acinetobacter strains were 7.02%(4/57), 13.89%(5/36), respectively. Conjugative plasmid didn′t play an important role in the formation and dissemination of drug resistance of P. aeruginosa and Acinetobacter.

Preventing Implant Bacterial Infections with Interconnected 3D Porous Structures (I3D)— A Proof-of-Concept Study

Oral antibiotics are often prescribed to prevent infection after implant surgery;however, only a small fraction of the antibiotics can reach the implants. Thus, there are concerns about overusing antibiotics. We designed and fabricated porous implants with interconnecting 3D structures (I3D) and hypothesized that such I3D structures could serve as a depository for antimicrobial agents to prevent infection locally. The implants were either treated with antibiotics or coated with silver nanoparticles (AgNPs) by electrodeposition to test this hypothesis. The antimicrobial assay was conducted, and bacterial growth zones of inhibition (ZOIs) were monitored. Overall, I3D implants resulted in larger ZOIs than did the solid implants, and the center I3D (cI3D)-implant produced the largest ZOI. In the antibiotic treatment testing, the diameters of ZOIs of the solid implant vs. I3D implant were about 14 mm vs. 15 to 18 mm on day 2;however, the diameter quickly reduced to 9 mm on day 3 and 5 mm on days 6 and 8 for the solid implant, while no obvious change of the zone was seen for I3D implants. For the AgNPs coated implants, the ZOIs for the I3D implants were generally greater than the solid implant over four weeks of incubation. A significantly larger ZOI (~1 - 2 mm larger on average) was seen for AgNPs coated I3D implants at 0.1 V - 0.01 M, 0.3 V - 0.01 M, and 1.5 V - 0.01 M treatments compared to AgNPs coated solid implants. Given that we have previously shown that I3D implants can reserve chemoattractants to recruit stem cells to enhance osseointegration, we conclude that implants with the I3D structures could be beneficial not only for osseointegration but also in preventing infection.

Effective antimicrobial therapies of urinary tract infections among children in low-and middle-income countries:A systematic review

Importance:Urinary tract infection(UTI)is one of the most common infections encountered in infancy and childhood.Despite the emerging problem of antibiotic resistance in recent years,the use of antibiotics for better management of UTIs is inevitable.Objective:This study aims to explore the efficacy and adverse effects of the available antimicrobial agents that are used in pediatric UTIs in low-and middle-income countries(LMICs).Methods:Five electronic databases were searched to identify relevant articles.Two reviewers independently performed screening,data extraction,and quality assessment of the available literature.Randomized controlled trials providing antimicrobial interventions in both male and female participants within the age range of 3 months to 17 years in LMICs were included.Results:Six randomized controlled trials from 13 LMICs were included in this review(four trials explored the efficacy).Due to high heterogeneity across the studies,a meta-analysis was not performed.Other than attrition and reporting bias,the risk of bias was moderate to high due to poor study designs.The differences in the efficacy and adverse events of different antimicrobials were not found to be statistically significant.Interpretation:This review indicates the necessity for additional clinical trials on children from LMICs with more significant sample numbers,adequate intervention periods,and study design.

A proposed model for understanding human-bacterial interactions:Space-time approach on community Escherichia coli occurrence and resistance phenomenon

Due to ecological effect, it is expected that population exposures to antimicrobial drugs may lead to microorganisms’ modifications, occasionally leading to resistance emergence. The present review was based on previous empirical data and on related literature search for quantitative empirical models exploring the human-bacterial interactions. Our previous studies have shown the emergence of ciprofloxacin resistant (CIP-R) Escherichia coli significantly related to previous specific levels of ciprofloxacin consumption and to urban clusters of CIP-R E. coli. The evidence of significant spatial clustering of antimicrobial resistance (ciprofloxacin resistance E. coli) reinforces the ecological effect hypothesis as a major drive in resistance emergence. In other words, human populations submitted to a certain ciprofloxacin or quinolone usage level may affect neighbours within certain geographical areas, not necessarily due to individual antimicrobial intake, but as a driving pressure over a modified circulating E. coli population. Apparently quantitative spatial-temporal analytical frameworks may be better for understanding human-bacterial interactions based on any of their epiphenomena (antimicrobial consumption, antimicrobial resistance, geno/phenotypic characteristics).

Tissue-Engineered Products for Skin Regenerative Medicine

In a general wound healing process, foreign bodies and tissue detritus have to be broken down and then a new tissue is produced. However, the new tissue formation sometimes fails to proceed under the impaired conditions such as burn injury and intractable skin ulcer. A major obstruction to wound healing is infection. Another obstruction to wound healing is deficiency of growth factors. The endogenous levels of growth factors are reduced in some chronic wounds. To improve these wound conditions, researchers have been trying to create several types of artificial skins. The tissue-engineered products include three prime constituents, i.e., cells, growth factors, and materials. In this review, the practical design of tissue-engineered products for skin regenerative medicine is introduced. The first design makes it possible to release silver sulfadiazine (AgSD) from a wound dressing. The second design makes it possible to release Epidermal Growth Factor (EGF) from a wound dressing or a skin care product composed of hyaluronic acid spongy sheet containing bioactive ingredients. The third design makes it possible to release several types of growth factors from allogeneic fibroblasts within cultured dermal substitute. This tissue-engineered product is prepared by seeding allogeneic fibroblasts into a collagen and hyaluronic acid spongy sheet. Although allogeneic cells are rejected gradually in immune system, they are able to release some types of growth factors, thereby regenerating a damaged tissue. The clinical study demonstrates that these tissue-engineered products are promising for the treatment of burn injury and intractable skin ulcer.

RESEARCH OF ANTIMICROBIAL AND RESISTANCE MODIFYING AGENTS FROM BENINESE PLANTS USED IN TRADITIONAL MEDICINE

In a world of increasing resistance to current antibiotics,search of novel therapeutic options is urgently needed.The aim of this work was to screen plant crude extracts for direct or indirect(inhibition of resistance)antimicrobial activity.Four crude extracts from 12 plants traditionally used in Benin for the treatment of infections were