Multidrug-resistant Pathogenic Bacteria Research Articles

Biocontrol of multi-drug resistant pathogenic bacteria in drainage water by locally isolated bacteriophage

In areas with limited water resources, the reuse of treated drainage water for non-potable purposes is increasingly recognised as a valuable and sustainable water resource. Numerous pathogenic bacteria found in drainage water have a detrimental impact on public health. The emergence of antibiotic-resistant bacteria and the current worldwide delay in the production of new antibiotics may make the issue of this microbial water pollution even more challenging. This challenge aided the resumption of phage treatment to address this alarming issue. In this study, strains of Escherichia coli and Pseudomonas aeruginosa and their phages were isolated from drainage and surface water from Bahr El-Baqar and El-Manzala Lake in Damietta governorate, Egypt. Bacterial strains were identified by microscopical and biochemical examinations which were confirmed by 16 S rDNA sequencing. The susceptibility of these bacteria to several antibiotics revealed that most of the isolates had multiple antibiotic resistances (MAR). The calculated MAR index values (> 0.25) categorized study sites as potentially hazardous to health. Lytic bacteriophages against these multidrug-resistant strains of E. coli and P. aeruginosa were isolated and characterized. The isolated phages were found to be pH and heat stable and were all members of the Caudovirales order as recognized by the electron microscope. They infect 88.9% of E. coli strains and 100% of P. aeruginosa strains examined. Under laboratory conditions, the use of a phage cocktail resulted in a considerable reduction in bacterial growth. The removal efficiency (%) for E. coli and P. aeruginosa colonies increased with time and maximized at 24 h revealing a nearly 100% reduction after incubation with the phage mixture. The study candidates new phages for detecting and controlling other bacterial pathogens of public health concern to limit water pollution and maintain adequate hygiene.

CHARACTERIZATION OF DRUG RESISTANT BACTERIA ISOLATED FROM SUBURBAN RAILWAY STATION PREMISES

Pathogens in public areas e.g. public transport system can be a critical public health issue due to ease of transfer. Present study deals with isolation and characterization of pathogenic bacteria from touch surfaces of railway station premises. A total of 53 swab samples taken from different touch surfaces were processed by classical microbiological procedures. Isolates were subjected to antibiotic sensitivity test. Further modified disinfectant challenge test was used to compare effectiveness of four commonly used disinfectants. Overall total 73 isolates were obtained. After morphological, cultural and biochemical analysis 7 isolates were identified as Methicillin resistant Staphylococcus aureus (MRSA) and 6 isolates as extended spectrum β-lactamase producing (ESBL) Escherichia coli. By virtue, these all were multidrug resistant. A disinfectant challenge test revealed Sodium hypochlorite, Dettol, MEDNTEK - R82 were effective while Santavis, a locally available disinfectant cum floor cleaner was not effective at recommended dilutions. Presence of multi drug resistant pathogenic bacteria in premises of railway station is extremely worrisome finding. Appropriate cleaning and disinfection measures required to prevent dissemination of these pathogens.

Evaluation Biosynthesized Silver Nanoparticles By Phomatropica Against Some Multidrug Resistance Bacterial Isolates

Researchers describe the extracellular manufacture of silver nanoparticles (AgNPs) from Phomatropica and its effectiveness against certain multidrug-resistant pathogenic bacteria that were obtained from the Central Laboratory of Quran Hospital. These bacteria were pathogenic. The AgNPs were synthesized and characterized by scan electrons microscopy, Fourier transform infrared spectroscopy, UV-visiblespectrophotometer that established the mostly spherical nanoparticles synthesis with size range between 55-99 nm. The potential antimicrobial activity was reported vs (Staphylococcus aureus, Pseudomonas aeruginosa, Klebsiella pneumonia, and Escherichia coli)by well diffusion method.AgNPs showed different inhibitory areas at different concentrations, the 50μg/mlconcentration of AgNPsappeared inhibition zones varied from(0-21 mm), while at 100 μg/mlofAgNPs varied between (13-25mm) vs the tested pathogenic bacterial strains in this investigation. Nevertheless, the synergetic impact of AgNPs with antibiotics have beendetected in the increasing the inhibitory impact vs the pathogenic bacteria. In conclusion, Extracellular biosynthesis appears to be a scalable and sustainable process. Because of their biogenic nature, these Ag-NPs might be a better medication candidate and have the potential to completely eliminate the issue of chemical agents.Antibiotic-resistant bacteria are proliferating at an alarming rate. To address this issue, the development of bactericidal agents is critical. AgNPs may provide a solution for drug-resistant bacteria.

EFFECT OF ESSENTIAL OILS ON MULTIDRUG RESISTANT GRAM-NEGATIVE BACTERIA

Obtaining healthy food, free from chemical or synthetic additives, is a major challenge. In this study, we developed a preservation method using essential oils and evaluated their effect on multidrug resistant pathogenic Gram-negative bacteria. Different concentrations (1%,0.1%,0.17% and 0.35%) of Thyme oil and black seed oil were employed in this study against pathogenic E. coli and A. hydrophila in soft cheese. The used oils at a concentration of 0.1% through dipping method resulted in accepted color and odor, little effect on flavor and normal texture and appearance, while 0.1% during inoculation had the same effect as in dipping method except moderate odor. Thyme oil had the highest reduction rate in case of 1% dipping and 0.17% inoculation on A. hydrophila, while against E. coli it was found that 0.17% inoculation and 0.35% of the dipping method had the highest reduction effect. Thyme essential oil seems to be a suitable natural food preservative alternative.

Detection of Morganella morganii bound to a plastic substrate in surface water

ObjectivesAround the globe, escalation in rare opportunistic microbial infections is alarming as they are heading steadily towards 'superbug' status. In aquatic ecosystems, plastic fosters multidrug-resistant pathogenic bacteria and plays a significant role in trafficking antibiotic-resistant genes. In this study, we focused on a multidrug-resistant bacterial strain isolated from microbial communities found on plastic substrates of a volcanic lake in central Italy. MethodsExtended-spectrum beta-lactamase-producing strains were isolated from both raw water and plastic substrates for a comparative investigation using microbiological and molecular methods, and antibiotic susceptibility profiling was performed against a panel of ten antibiotics. ResultsMolecular identification and Basic Local Alignment Search Tool analysis confirmed an almost identical sequencing pattern of two isolated strains and their homology with Morganella morganii. Antibiotic susceptibility tests revealed their resistance to almost all tested antibiotics. Class 1 integron-associated gene (intI1) and seven antibiotic resistance genes were detected in both strains, confirming their superbug status. ConclusionTo our knowledge, this is the first study on the characterization of extended-spectrum beta-lactamase-producing M. morganii isolated from the biofilm of plastic substrates, depicting the potential toxicity of plastic in harbouring and dispersing virulent, multidrug-resistant, opportunistic human pathogens.

Interactions of Chitosan-coated Green Synthesized Silver Nanoparticles using Mentha spicata and Standard Antibiotics against Bacterial Pathogens.

Infectious diseases are caused by various multidrug-resistant pathogenic bacteria and in recent scenarios, nanoparticles have been used as innovative antimicrobial agents. This current research aimed to evaluate the bactericidal effect of chitosan-coated green synthesized silver nanoparticles using aqueous extract of Mentha spicata (MSaqu) against bacterial pathogens, i.e., Pseudomonas aeruginosa, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Serratia marcescens, Staphylococcus aureus, and Streptococcus pyogenes. Synthesis and characterization of silver nanoparticles (MSAgNPs) were carried out via atomic absorption spectrometer and Fourier-transform infrared spectroscopy. Agar well and agar disc diffusion methods were used to assess the antibacterial and synergistic effect of chitosanmediated biogenic silver nanoparticles and standard antibiotics. Three types of interactions, i.e., antagonistic (↓), synergistic (↑), and additive (¥) were observed. Synergistic effect was recorded against Pseudomonas aeruginosa (8.5±0.25 mm↑), Serratia marcescens (19.0±1.0 mm↑), and Klebsiela pneumonia (8.5±0.25 mm↑), an additive effect was exhibited by Escherichia coli (9.0±0.0 mm¥), Streptococcus pyogenes (10.0±0.0 mm¥), and Staphylococcus aureus (7.5±0.25 mm↓) and they showed antagonistic effects when chitosan-coated silver nanoparticles (CLMSAgNPs) were applied compared to chitosan, MSaqu, and MSAgNPs. Interesting antibacterial results were recorded when chitosan-coated Mentha spicata extract and silver nanoparticles were applied along with antibiotics. The synergistic effects of chitosan-coated silver nanoparticles (CLMSAgNPs) + K were recorded against E. coli (14.5±0.25 mm). The synergistic effects of chitosan-coated silver nanoparticles (CLMSAgNPs) + AML were recorded against E. coli (5.5±0.0 mm), S. pyogenes (10.0±0.0 mm), K. pneumonia (5.5±0.0 mm), and S. aureus (4.0±0.0 mm). The synergistic effects of chitosan-coated silver nanoparticles (CLMSAgNPs) + NOR were recorded against E. coli (16.0±0.0 mm), P. aeruginosa (19.0±0.0 mm), S. marcescens (19.5±0.25 mm), S. pyogenes (11.5.0±0.25 mm), K. pneumonia (23.0±0.0 mm), and S. aureus (8.5±0.25 mm). Current findings concluded that chitosan-coated biogenic silver nanoparticles have potential bactericidal effects against infectious pathogens and could be used as forthcoming antibacterial agents.

Antibacterial effect of Lignin Polymer on Multidrug Resistant Bacteria Identified by Vitek System

Background: Widespread usage of antimicrobial drugs has increased the emergence of antibiotic-resistant pathogens and that's why we need new drugs. Lignin and its derivatives considered as an antioxidant, anti-inflammatory, insecticidal and antimicrobial. This study aimed to investigate the effect of lignin polymer against the bacteria isolated from clinical samples, and to study the antibiotic resistance pattern using the Vitek system. Materials and Methods: 50 clinical bacterial samples were collected from two hospitals in Baghdad city. All the isolates of Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus were subjected to Vitek system to determine the resistance for 12 antibiotics. The Soda lignin polymer had been prepared from the palm tree empty fruit/ Malaysia. The biological activity of lignin polymer against resistant bacteria was evaluated by well agar diffusion method. Results: According to the Vitek system, all the bacterial isolates were multi-resistance to many antibiotics. Lignin polymer dilutions inhibited the growth of some bacterial isolates, and it was more effective in all the concentrations with a good inhibition zone on Pseudomonas aeruginosa which reached to 20mm. Conclusion: Lignin polymer has an antibacterial effect against some pathogenic multidrug resistant bacteria isolated from clinical samples, including urine and wound infection. Lignin polymer was more effective in all the concentrations on the isolates of Pseudomonas aeruginosa, with a good inhibition zone.

Antimicrobial resistance pattern of bacteria isolated from broiler meat with the determination of antibiotic residue

Objective: This study was outlined for the isolation and identification of some zoonotic bacte¬ria present in broiler meat, along with the investigation of antimicrobial resistance patterns and determination of antibiotic residue. Materials and Methods: 45 raw meat samples were collected from different restaurants in Mymensingh. Staphylococcus spp., Escherichia coli, Salmonella spp., Proteus spp., and Citrobacter spp. were detected through cultural, morphological, and biochemical tests. The E. coli were identified by amplification of malB gene, and Staphylococcus aureus was identified by targeting 16r- RNA gene. The disc diffusion method was applied for the antibiogram investigation. Thin layer chromatography was performed to determine the antibiotic residue within the broiler meat. Results: Staphylococcus spp., E. coli, Salmonella spp., Proteus spp., and Citrobacter spp. were detected with a prevalence of 93.33% (42/45), 35.56% (16/45), 2.22% (1/45), 8.89% (4/45), and 13.33% (6/45), respectively. Antibiogram study revealed that Staphylococcus spp. showed the highest resistance to Trimethoprim and Oxytetracycline (75%), and the highest sensitivity was observed toward Gentamycin. The antibiogram profile of E. coli revealed 100% resistance to Oxytetracycline and 100% sensitivity to Gentamycin. Salmonella spp. showed resistance to Ciprofloxacin, Enrofloxacin, and Levofloxacin and was sensitive to Florfenicol and Gentamycin. The antibiotic profile of Proteus spp. exhibited 66.7% resistance to Trimethoprim, Ciprofloxacin, and Enrofloxacin. Citrobacter spp. showed 100% resistance to Trimethoprim, 66.7% resistance to Levofloxacin, and 100% sensitivity was observed to Florfenicol, Gentamycin, and Norfloxacin. The antibiotic residue of Ciprofloxacin, Levofloxacin, Oxytetracycline, and Enrofloxacin was also determined. In the case of antibiotic residue determination, the residue of Levofloxacin, Oxytetracycline, and Ciprofloxacin was found to be 6.67%, 6.67%, and 13.33%, respectively. Conclusion: This study revealed the existence of some multidrug-resistant pathogenic bacteria and higher limits of antibiotic residue in broiler meat and liver which may affect human health.

Galbanic acid, a sesquiterpene coumarin as a novel candidate for the biosynthesis of silver nanoparticles: In vitro hemocompatibility, antiproliferative, antibacterial, antioxidant, and anti-inflammatory properties

In the current study, silver nanoparticles (AgNPs) were biosynthesized using galbanic acid (GA), a sesquiterpene coumarin. The formation of GA-AgNPs was characterized by ultraviolet–visible (UV–Vis) spectroscopy, Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), Energy Dispersive X-ray (EDX), and X-ray diffraction (XRD). The biosynthesized GA-AgNPs were spherical in shape with an average particle size of 142.33 ± 32.6 nm. The results from the antibacterial assays suggested that biosynthesized GA-AgNPs were more potent against multi-drug resistant (MDR) and non-MDR pathogenic bacteria than the crude GA alone. The nanoparticles also showed potent antiproliferative potential against H1229 and MCF-7 cancer cells with IC50 values of 25 μg/mL and 50 μg/mL by the MTT assay, respectively. These NPs showed good antioxidant (30 % at 100 µg/mL), anti-inflammatory (99.5 % at 500 µg/mL), and anti-coagulant properties without significant hemolysis on red blood cells (RBCs). These results confirm the benefits of using the green, simple, and cost-effective manner for the synthesis of AgNPs with excellent biological properties and hemocompatibility.

Antioxidant and Antimicrobial Properties of Selected Phytogenics for Sustainable Poultry Production

The use of antibiotic growth promoters (AGP) in poultry production not only promotes the emergence of pathogenic multi-drug resistant bacteria, but it also compromises product quality, threatens animal and human health, and pollutes the environment. However, the complete withdrawal of AGP without alternatives could result in uncontrollable disease outbreaks that would jeopardize large-scale poultry intensification. Thus, the use of phytogenic products as potential alternatives to in-feed AGP has attracted worldwide research interest. These phytogenic products contain numerous biologically active substances with antioxidant and antimicrobial activities that can enhance poultry health, growth performance, and meat quality characteristics. In addition, the incorporation of phytogenic products as feed additives in poultry diets could result in the production of high-quality, drug-free, and organic poultry products that are safe for human consumption. Thus, this review examines the current evidence on the antioxidant and antimicrobial properties of a selection of phytogenic products, their effects on nutrient utilization, and physiological and meat quality parameters in poultry. The paper also reviews the factors that could limit the utilization of phytogenic products in poultry nutrition and proposes solutions that can deliver efficient and sustainable poultry production systems for global food and nutrition security.

Chitosan-Coated Polymeric Silver and Gold Nanoparticles: Biosynthesis, Characterization and Potential Antibacterial Applications: A Review.

Biosynthesized metal nanoparticles, especially silver and gold nanoparticles, and their conjugates with biopolymers have immense potential in various fields of science due to their enormous applications, including biomedical applications. Polymeric nanoparticles are particles of small sizes from 1 nm to 1000 nm. Among different polymeric nanoparticles, chitosan-coated silver and gold nanoparticles have gained significant interest from researchers due to their various biomedical applications, such as anti-cancer, antibacterial, antiviral, antifungal, anti-inflammatory technologies, as well as targeted drug delivery, etc. Multidrug-resistant pathogenic bacteria have become a serious threat to public health day by day. Novel, effective, and safe antibacterial agents are required to control these multidrug-resistant pathogenic microorganisms. Chitosan-coated silver and gold nanoparticles could be effective and safe agents for controlling these pathogens. It is proven that both chitosan and silver or gold nanoparticles have strong antibacterial activity. By the conjugation of biopolymer chitosan with silver or gold nanoparticles, the stability and antibacterial efficacy against multidrug-resistant pathogenic bacteria will be increased significantly, as well as their toxicity in humans being decreased. In recent years, chitosan-coated silver and gold nanoparticles have been increasingly investigated due to their potential applications in nanomedicine. This review discusses the biologically facile, rapid, and ecofriendly synthesis of chitosan-coated silver and gold nanoparticles; their characterization; and potential antibacterial applications against multidrug-resistant pathogenic bacteria.

Tackling Antibiotic Resistance: Influence of Aliphatic Branches on Broad-Spectrum Antibacterial Polytriazoles against ESKAPE Group Pathogens.

One of the most important threats to public health is the appearance of multidrug-resistant pathogenic bacteria, since they are the cause of a high number of deaths worldwide. Consequently, the preparation of new effective antibacterial agents that do not generate antimicrobial resistance is urgently required. We report on the synthesis of new linear cationic antibacterial polytriazoles that could be a potential source of new antibacterial compounds. These polymers were prepared by thermal- or copper-catalyzed click reactions of azide and alkyne functions. The antibacterial activity of these materials can be modulated by varying the size or nature of their side chains, as this alters the hydrophilic/hydrophobic balance. Antibacterial activity was tested against pathogens of the ESKAPE group. The P3TD polymer, which has butylated side chains, was found to have the highest bactericidal activity. The toxicity of selected polytriazoles was investigated using human red blood cells and a human gingival fibroblast cell line. The propensity of prepared polytriazoles to induce resistance in certain bacteria was studied. Some of them were found to not produce resistance in methicillin-resistant Staphylococcus aureus or Pseudomonas aeruginosa. The interaction of these polytriazoles with the Escherichia coli membrane produces both depolarization and disruption of the membrane.

Green synthesis of chitosan nanoparticles, optimization, characterization and antibacterial efficacy against multi drug resistant biofilm-forming Acinetobacterbaumannii

Chitosan nanoparticles (CNPs) are promising versatile cationic polymeric nanoparticles, which have received growing interest over last few decades. The biocompatibility, biodegradability, environmental safety and non-toxicity of the chitosan nanoparticles makes it preferred for a wide range of biological applications including agriculture, medical and pharmaceutical fields. In this study, CNPs were biosynthesized by aqueous extract of Eucalyptusglobulus Labill fresh leaves as bio-reductant. Box–Behnken design in 29 experimental runs was used for optimization of different factors affecting the production of CNPs. The maximum yield of CNPs was 9.91 mg/mL at pH of 4.5, chitosan concentration of 1%, incubation time of 60 min and temperature of 50 °C. The crystallinity, particle size and morphology of the biosynthesized CNPs were characterized. The CNPs possess a positively charged surface of 31.1 mV. The SEM images of the CNPs confirms the formation of spherical form with smooth surface. The TEM images show CNPs were spherical in shape and their size range was between 6.92 and 10.10 nm. X-ray diffraction indicates the high degree of CNPs crystallinity. FTIR analysis revealed various functional groups of organic compounds including NH, NH2, C–H, C−O, C–N, O–H, C–C, C–OH and C–O–C. The thermogravimetric analysis results revealed that CNPs are thermally stable. The antibacterial activity of CNPs was determined against pathogenic multidrug-resistant bacteria, Acinetobacterbaumannii. The diameters of the inhibition zones were 12, 16 and 30 mm using the concentrations of 12.5, 25 and 50 mg/mL; respectively. When compared to previous studies, the biosynthesized CNPs produced using an aqueous extract of fresh Eucalyptusglobulus Labill leaves have the smallest particle sizes (with a size range between 6.92 and 10.10 nm). Consequently, it is a promising candidate for a diverse range of medical applications and pharmaceutical industries.

Biosynthesized Gold, Silver, Palladium, Platinum, Copper, and Other Transition Metal Nanoparticles.

Nanomedicine is a potential provider of novel therapeutic and diagnostic routes of treatment. Considering the development of multidrug resistance in pathogenic bacteria and the commonness of cancer, novel approaches are being sought for the safe and efficient synthesis of new nanoparticles, which have multifaceted applications in medicine. Unfortunately, the chemical synthesis of nanoparticles raises justified environmental concerns. A significant problem in their widespread use is also the toxicity of compounds that maintain nanoparticle stability, which significantly limits their clinical use. An opportunity for their more extensive application is the utilization of plants, fungi, and bacteria for nanoparticle biosynthesis. Extracts from natural sources can reduce metal ions in nanoparticles and stabilize them with non-toxic extract components.

Targeting TPP Riboswitches Using Chimeric Antisense Oligonucleotide Technology for Antibacterial Drug Development.

Nowadays, the emergence and the transmission of multidrug-resistant pathogenic bacteria are a severe menace mounting a lot of pressure on the healthcare systems worldwide. Many severe outbreaks of bacterial infections have been reported worldwide in recent years. Thus, there is an immediate demand to develop antibiotics. Some riboswitches are potential targets for overcoming bacterial resistance. This paper demonstrates the bacteriostatic effect of an antisense oligonucleotide (ASO) engineered to suppress the growth of pathogenic bacteria such as Listeria monocytogenes by targeting the Thiamine Pyrophosphate (TPP) riboswitch. It does not inhibit the growth of the conditional pathogenic bacteria Escherichia coli, as it lacks the TPP riboswitch, showing the specificity of action of our ASO. It is covalently bonded with the cell-penetrating protein pVEC. We did bioinformatics analyses of the thiamine pyrophosphate riboswitch regarding its role in synthesizing the metabolite thiamine pyrophosphate, which is essential for bacteria. L. monocytogenes is intrinsically resistant to cephalosporins and usually is treated with ampicillin. A dosage of ASO has been established that inhibits 80% of bacterial growth at 700 nM (4.5 μg/mL). Thus, the TPP riboswitch is a valuable antibacterial target.

Detection of multidrug resistant pathogenic bacteria and novel complex class 1 integrons in campus atmospheric particulate matters

Recent advances provided overwhelming evidence that atmospheric particulate matters carry a substantial amount of antibiotic resistance genes (ARGs). It has also been documented that polluted air facilitates transmission of bacterial pathogenesis and antimicrobial resistance (AMR). These investigations generally used culture-independent approaches which reveal sophisticated microbiomic and resistomic compositions in particulate matters, while culture-dependent methods directly demonstrating presence of live, functional bacteria has not been fully applied. In recent years, efforts undertaken worldwide managed to reduce air particulate matter pollution, leading to cleaner air in many parts of world, including China. Whether atmospheric particulate matters may still function as vehicles for pathogenic bacteria and AMR in improving air conditions is turning into an interesting question to address. In attempt to answer this question, a culture-dependent approach is used to find out the putative role of atmospheric particulate matters in relatively ‘clean’ air to transmit pathogenic bacteria and AMR in this work. By harvesting particulate matters in an unindustrialized and less-polluted university campus, culturing and identifying bacteria in particulate matters, and characterizing pathogenesis and AMR properties of these bacteria, interesting findings were made that even in relatively ‘clean’ air, antibiotic-resistant pathogenic bacteria are prevalent; and that mobile genetic elements including integrons are widespread. In particular, in air samples collected, multidrug-resistant hemolytic Bacillus strains that may pose significant health threat could be identified. Complex class 1 integrons, two of which carry novel antibiotic resistant gene cassette arrays, were also found for the first time in airborne bacteria, suggesting the danger of horizontal transfer of AMR in air. In conclusion, using culture-dependent methods, this work shows that atmospheric particulate matters are viable vehicles for the transmission of bacterial pathogenesis and AMR, and that even in relatively ‘clean’ air, the threat of airborne antibiotic-resistant pathogens is significant.

Characterisation of broad-spectrum phiKZ like jumbo phage and its utilisation in controlling multidrug-resistant Pseudomonas aeruginosa isolates

The emergence of highly virulent multidrug-resistant P. aeruginosa has become increasingly evident among hospital-acquired infections and has raised the need for alternative therapies. Phage therapy can be one such alternative to antibiotic therapy to combat multidrug-resistant pathogenic bacteria, but this requires the availability of phages with a broad host range. In this study, isolation and molecular characterisation of P. aeruginosa specific phages were carried out. A total of 17 phages isolated showed different spectra of activity and efficiency of lysis against 82 isolates of P. aeruginosa obtained from clinical samples (n = 13), hospital effluent (n = 46) and fish processing plant effluent (n = 23). Antibiotic susceptibility test results revealed multi-drug resistance in 61 of the total 82 isolates. Three new jumbo lytic P. aeruginosa specific broad host range phages were isolated and characterised in this present study belonged to the family Myoviridae (order Caudovirales). The genetic analysis of ɸU5 revealed that phage has a genome size of 282.6 kbp with 373 putative open reading frames (ORFs), and its genetic architecture is similar to phiKZ like jumbo phages infecting P. aeruginosa. The bacteriophages isolated in this study had lytic ability against biofilm-forming and multidrug-resistant P. aeruginosa and could be candidates for further studies towards phage therapy.

Phytogenic silver nanoparticles from tissue-cultured Kaempferia angustifolia — an underutilized medicinal herb: a comparative antibacterial study on urinary pathogens

BackgroundEthnomedicinally important Kaempferia angustifolia is a rhizomatous aromatic herb belonging to the family Zingiberaceae. The present manuscript deals with the green synthesis of silver nanoparticles through a rapid reduction process mediated by the rhizome extract of tissue culture-raised plants. The present study was conducted to evaluate the antimicrobial activity of the bio-nanoparticles, and the plant extracts themselves against seven multidrug-resistant urinary tract infecting (MDR-UTI) pathogens. ResultThe ethanolic extracts of the rhizomes of the plant executed a very rapid synthesis of silver bio-nanoparticles, and the generation of the nanoparticles was confirmed through UV-vis spectrophotometry, dynamic light scattering (DLS), and electron dispersion spectroscopic (EDS) analysis. Finally, the precise shapes and dimensions of these nanoparticles were confirmed under the transmission electron microscope (TEM). The shapes of the nanoparticles obtained were diverse in nature and varied from rod, triangular, spherical, to oval shaped, with the size, ranging from 10–60 nm. Silver nanoparticles exhibited a maximum zone of inhibition (ZI) of 16.93 ± 0.04 mm against isolate no. 42332. The ex vitro and in vivo extracts exhibited ZI 14.03 ± 0.04 mm and 11.56 ± 0.04 mm, respectively, against the same strain, which are comparatively lower than the nanoparticles but unignorable. ConclusionAlthough the pathogens used in the present study are resistant to at least three or more types of pharmacologically important antibiotics, nanoparticles, as well as the plant extracts, exhibited significant inhibition to all the seven MDR-UTI pathogens, which confirms that they are highly antimicrobic. Hence, this underutilized medicinal plant extracts of K. angustifolia and the bio-nanoparticles synthesized from these can be explored in pharmaceutical industries to treat multidrug-resistant human pathogenic bacteria. Furthermore, their broad-spectrum activity leads to the opportunity for the synthesis of future generation drugs.

A New Saharan Strain of Streptomyces sp. GSB-11 Produces Maculosin and N-acetyltyramine Active Against Multidrug-Resistant Pathogenic Bacteria.

Multi-resistant bacterial pathogens are a major public health problem for treating nosocomial infections owing to their high resistance to antibiotics. The objective of this research was to characterize the bioactive molecules secreted by a novel moderately halophilic actinobacterium strain, designated GSB-11, exhibiting a strong antagonistic activity against several multidrug-resistant pathogenic bacteria. This potential strain was identified by phenotypic, genotypic (16S rRNA), and phylogenetic analyses. GSB-11 was related to "Streptomycesacrimycini" NBRC 12736T with 99.59% similarity. Molecular screening by PCR assay demonstrated that the strain possesses two biosynthetic genes coding for NRPS and PKS-II. Two active compounds GSB11-6 and GSB11-7 were extracted from the cell-free culture supernatant of Bennett medium and purified using reversed-phase HPLC. According to spectrometric (mass spectrum) and spectroscopic (1H NMR, 13C NMR, 1H-1H COSY, and 1H-13C HMBC) spectra analyses, the compounds GSB11-6 and GSB11-7 were identified to be maculosin and N-acetyltyramine, respectively. Their minimum inhibitory concentrations (MIC) revealed interesting values against certain multidrug-resistant pathogenic bacteria. They were between 5 and 15mg/mL for GSB11-6, 10 and 30mg/mL for GSB11-7. To our best knowledge, this is the first study of these active substances isolated from "Streptomycesacrimycini" showing an interesting antibacterial activity. Therefore, these essential compounds could be candidates for future research against multidrug-resistant bacteria.

A Brominated Furanone Inhibits Pseudomonas aeruginosa Quorum Sensing and Type III Secretion, Attenuating Its Virulence in a Murine Cutaneous Abscess Model.

Quorum sensing (QS) and type III secretion systems (T3SSs) are among the most attractive anti-virulence targets for combating multidrug-resistant pathogenic bacteria. Some halogenated furanones reduce QS-associated virulence, but their role in T3SS inhibition remains unclear. This study aimed to assess the inhibition of these two systems on Pseudomonas aeruginosa virulence. The halogenated furanones (Z)-4-bromo-5-(bromomethylene)-2(5H) (C-30) and 5-(dibromomethylene)-2(5H) (named hereafter GBr) were synthesized, and their ability to inhibit the secretion of type III exoenzymes and QS-controlled virulence factors was analyzed in P. aeruginosa PA14 and two clinical isolates. Furthermore, their ability to prevent bacterial establishment was determined in a murine cutaneous abscess model. The GBr furanone reduced pyocyanin production, biofilm formation, and swarming motility in the same manner or more effectively than C-30. Moreover, both furanones inhibited the secretion of ExoS, ExoT, or ExoU effectors in all tested strains. The administration of GBr (25 and 50 µM) to CD1 mice infected with the PA14 strain significantly decreased necrosis formation in the inoculation zone and the systemic spread of bacteria more efficiently than C-30 (50 µM). Molecular docking analysis suggested that the gem position of bromine in GBr increases its affinity for the active site of the QS LasR regulator. Overall, our findings showed that the GBr furanone displayed efficient multi-target properties that may favor the development of more effective anti-virulence therapies.