Number Of Antibiotic-resistant Bacteria Research Articles

Bacteriophages: the possible solution to treat infections caused by pathogenic bacteria.

Since their discovery in 1915, bacteriophages have been used to treat bacterial infections in animals and humans because of their unique ability to infect their specific bacterial hosts without affecting other bacterial populations. The research carried out in this field throughout the 20th century, largely in Georgia, part of USSR and Poland, led to the establishment of phage therapy protocols. However, the discovery of penicillin and sulfonamide antibiotics in the Western World during the 1930s was a setback in the advancement of phage therapy. The misuse of antibiotics has reduced their efficacy in controlling pathogens and has led to an increase in the number of antibiotic-resistant bacteria. As an alternative to antibiotics, bacteriophages have become a topic of interest with the emergence of multidrug-resistant bacteria, which are a threat to public health. Recent studies have indicated that bacteriophages can be used indirectly to detect pathogenic bacteria or directly as biocontrol agents. Moreover, they can be used to develop new molecules for clinical applications, vaccine production, drug design, and in the nanomedicine field via phage display.

Antibiotic Resistant Bacteria from Treated and Untreated Hospital Wastewater at Ayder Referral Hospital, Mekelle, North Ethiopia

The widespread emergence of antibiotic resistance among bacterial pathogens has become one of the most serious challenges in Ethiopia. This study determined the prevalence and drug resistance patterns of bacterial pathogens isolated from treated and untreated wastewater released from Ayder Referral Hospital in Northern Ethiopia. A cross sectional study design was conducted from September-December, 2015 in wastewater released from Ayder referral hospital. A total of 40 composite samples were aseptically collected, transported and processed for enumeration of indicator organisms, bacteriological identification and susceptibility testing following standard procedure. Data obtained were entered and analyzed using SPSS version 20. Mean heterotrophic plate count, total coliform count, fecal coliform count and E. coli count were found to be 1.6 × 106 CFU/mL, 2.2 × 106 CFU/100 mL, 2.0 × 105 CFU/100 mL and 1.1 × 104 CFU/100 mL from treated wastewater respectively. Among the total samples 134 bacterial isolates were detected and [84 (62.7%)] were from untreated wastewater and [50 (37.3%)] were from treated wastewater. The most frequently isolated bacteria from untreated wastewater samples was Klebsiella spp [14 (16.7%)] followed by S. aureus [13 (15.5%)] and P. aeruginosa [12 (14.3%)], similarly in treated wastewater samples Klebsiella spp [10 (20%)], P. aeruginosa [8 (16%)] and S. aureus [8 (16%)] were frequently detected. The overall multi-drug resistance (MDR) in this study was [79/134 (79.1%)]. MDR from untreated wastewater sample was [64/84 (76.2%)] while from treated wastewater sample was [42/50 (84%)] and shows significant difference with (COR: 1.64, 95% CI: 1.15 - 3.29, P: 0.001). It is concluded that treated hospital wastewater contains large numbers of antibiotic resistant bacteria. Therefore, there should be continuous monitoring and evaluation of the effluent quality of the ponds and chlorination of the final effluent should be developed.

Egg Yolk Antibodies for Disease Prevention

The general structure of the egg yolk antibody, containing of two light and two heavy chains, is comparable to that of mammalian immunoglobulins. Oral administration of specific egg yolk antibody is an attractive approach against gastrointestinal infection in humans and animals. The use of IgY as antibiotic-alternative therapy have advantages: (1) The production of IgY is a non-invasive and inexpensive method; (2) Handling of animal is easy; (3) Don’t need to bleeding of laboratory animals;(4) A laying hen is able to produce more than 20 g of IgY per year; (5) Eggs are normal dietary components and there is no risk of toxic side effects of IgY. The increasing number of antibiotic resistant bacteria confirm the need to find alternative to antibiotics such as IgY. Yolk antibodies have been shown in several studies to prevent bacterial and viral infections. The example of a successful prophylactic use of IgY is the treatment of diseases with specific IgY antibodies against Escherichia coli, Helicobacter pylori, Salmonella spp, Streptococcus mutans, Porphyromonas gingivalis, Pseudomonas aeruginosa, Candida albicans, rotavirus and coronavirus.

Lipid-Based Liquid Crystals As Carriers for Antimicrobial Peptides: Phase Behavior and Antimicrobial Effect.

The number of antibiotic-resistant bacteria is increasing worldwide, and the demand for novel antimicrobials is constantly growing. Antimicrobial peptides (AMPs) could be an important part of future treatment strategies of various bacterial infection diseases. However, AMPs have relatively low stability, because of proteolytic and chemical degradation. As a consequence, carrier systems protecting the AMPs are greatly needed, to achieve efficient treatments. In addition, the carrier system also must administrate the peptide in a controlled manner to match the therapeutic dose window. In this work, lyotropic liquid crystalline (LC) structures consisting of cubic glycerol monooleate/water and hexagonal glycerol monooleate/oleic acid/water have been examined as carriers for AMPs. These LC structures have the capability of solubilizing both hydrophilic and hydrophobic substances, as well as being biocompatible and biodegradable. Both bulk gels and discrete dispersed structures (i.e., cubosomes and hexosomes) have been studied. Three AMPs have been investigated with respect to phase stability of the LC structures and antimicrobial effect: AP114, DPK-060, and LL-37. Characterization of the LC structures was performed using small-angle X-ray scattering (SAXS), dynamic light scattering, ζ-potential, and cryogenic transmission electron microscopy (Cryo-TEM) and peptide loading efficacy by ultra performance liquid chromatography. The antimicrobial effect of the LCNPs was investigated in vitro using minimum inhibitory concentration (MIC) and time-kill assay. The most hydrophobic peptide (AP114) was shown to induce an increase in negative curvature of the cubic LC system. The most polar peptide (DPK-060) induced a decrease in negative curvature while LL-37 did not change the LC phase at all. The hexagonal LC phase was not affected by any of the AMPs. Moreover, cubosomes loaded with peptides AP114 and DPK-060 showed preserved antimicrobial activity, whereas particles loaded with peptide LL-37 displayed a loss in its broad-spectrum bactericidal properties. AMP-loaded hexosomes showed a reduction in antimicrobial activity.

Silk route to the acceptance and re-implementation of bacteriophage therapy.

This multidisciplinary expert panel opinion on bacteriophage therapy has been written in the context of a society that is confronted with an ever-increasing number of antibiotic resistant bacteria. To avoid the return to a pre-antibiotic era, alternative treatments are urgently needed. The authors aim to contribute to the opinion formation of relevant stakeholders on how to potentially develop an infrastructure and legislation that paves the way for the acceptance and re-implementation of bacteriophage therapy.

Synergism between antibiotics and plant extracts or essential oils with efflux pump inhibitory activity in coping with multidrug-resistant staphylococci

The alarming growth of the number of antibiotic resistant bacteria and in the same time limited possibilities to develop new antimicrobial compounds, lead to an urgent need to keep the sensitivity of bacteria against currently used antibiotics. Bacterial efflux pumps are an important mechanism of antibiotic resistance as the bacteria use efflux pumps for the extrusion of different types of antibiotics and chemicals. The knowledge about inhibitors of efflux pumps from natural sources suggests that this mechanism may be a good target for new drugs based on synergistic interactions of antibiotics with plant extracts, essential oils, or their constituents with efflux pump inhibitory activity. This review summarizes the current knowledge of staphylococcal efflux pumps and potential strategies to overcome them. Natural inhibitors of efflux pumps and their synergistic interactions with antibiotics are summarized.

The fight against bacterial resistance, a public health priority

The increase in the number of antibiotic resistant bacteria represents a major danger for the health of humans and animals. Combined with an almost complete absence of new antibiotics, it is one of the most alarming public health issues of our time. Measures must be taken in order to control the use of these drugs and safeguard their effectiveness.

Immersing undergraduate students into research on the metagenomics of the plant rhizosphere: a pedagogical strategy to engage civic-mindedness and retain undergraduates in STEM.

Do you find yourself teaching courses and watching the students' eyes glaze over, clearly disengaged from the class material? Are you concerned that bright young undergraduates spend too much time memorizing esoteric facts from a textbook and regurgitating them on exams rather than motivating themselves to delve deeply into scientific literature, explore the questions and issues confronting modern scientists, and seek out solutions by employing their critical thinking skills and creativity? Have you ever asked your undergraduate students how they would make 100 mL of a 10% sucrose solution and they don't know the answer? Students most certainly encounter this type of quantitative reasoning problem in their Chemistry courses, so are you surprised when transferring this highly practical skill set to analogous problems in a Biology course presents such a challenge to students? If any of these questions provokes a “yes,” you should consider offering a course that ties research and teaching together and at the same time addresses issues that are relevant to real life. By implementing such courses at UCLA, where we focus on global climate change, soil erosion and degradation, increasing numbers of antibiotic resistant bacteria, and non-sustainable farming and forestry practices for a growing human population, we have not only energized our own teaching, but also have inspired our students to become fully engaged in a scientific undertaking to contend with globally-relevant environmental issues confronting twenty-first century society.

Detection of Sulfonamide Resistance Genes via in situ PCR-FISH

Due to the rising use of antibiotics and as a consequence of their concentration in the environment an increasing number of antibiotic resistant bacteria is observed. The phenomenon has a hazardous impact on human and animal life. Sulfamethoxazole is one of the sulfonamides commonly detected in surface waters and soil. The aim of the study was to detect sulfamethoxazole resistance genes in activated sludge biocenosis by use of in situ PCR and/or hybridization. So far no FISH probes for the detection of SMX resistance genes have been described in the literature. We have tested common PCR primers used for SMX resistance genes detection as FISH probes as well as a combination of in situ PCR and FISH. Despite the presence of SMX resistance genes in activated sludge confirmed via traditional PCR, the detection of the genes via microscopic visualization failed.

Antimicrobial Photodynamic Efficiency of Novel Cationic Porphyrins towards Periodontal Gram‐positive and Gram‐negative Pathogenic Bacteria

The Gram-negative Aggregatibacter actinomycetemcomitans and Fusobacterium nucleatum are major causative agents of aggressive periodontal disease. Due to increase in the number of antibiotic-resistant bacteria, antimicrobial Photodynamic therapy (aPDT) seems to be a plausible alternative. In this work, photosensitization was performed on Gram-positive and Gram-negative bacteria in pure culture using new-age cationic porphyrins, namely mesoimidazolium-substituted porphyrin derivative (ImP) and pyridinium-substituted porphyrin derivative (PyP). The photophysical properties of both the sensitizers including absorption, fluorescence emission, quantum yields of the triplet excited states and singlet oxygen generation efficiencies were evaluated in the context of aPDT application. The studied porphyrins exhibited high ability to accumulate into bacterial cells with complete penetration into early stage biofilms. As compared with ImP, PyP was found to be more effective for photoinactivation of bacterial strains associated with periodontitis, without any signs of dark toxicity, owing to its high photocytotoxicity.

Mechanisms of abiotic horizontal gene transfer: Comment on “Lightning-triggered electroporation and electrofusion as possible contributors to natural horizontal gene transfer” by Tadej Kotnik

Results suggestive of horizontal (lateral) gene transfer, attributed at the time to mutations, have been published since early 20th century [3]. Recent advances in gene sequencing technology have set on solid ground the idea that horizontal (lateral) gene transfer (HTG) is an important factor in evolution [10,11]. There is an increasing interest in this phenomenon [4,8,12], which is now thought to be largely responsible for the growing number of antibiotic resistant bacteria in the world [23]. In this issue, Kotnik, has developed a convincing hypothesis that lightning induced electroporation and electrofusion could be a mechanism for abiotic horizontal gene transfer [13]. Electroporation and electrofusion, described in detail in [13], are mechanisms that involve the application of certain electric fields across a cell and the consequent formation of defects in the cell membrane. These defects can be reversible or irreversible. Reversible electroporation is commonly used for gene transfection and cell fusion while irreversible electroporation is used for cell ablation [13]. Lightning produces a range of electric fields that include those for reversible electroporation, irreversible electroporation and fusion. It is reasonable to assume that microorganisms and viruses exposed to lightning could be exposed to a combination of electric fields that will produce abiotic horizontal gene transfer, as suggested by Kotnik [13]. In fact, the group of Rafael Lee has shown that lightning can cause irreversible electroporation injury to tissue [1,14]. The idea that lighting can cause abiotic lateral gene transfer is somewhat reminiscent of the idea of abiogenesis and the classical experiment of Miller and Urey [17,18]. Could other mechanisms proposed for abiogenesis be also involved in abiotic gene transfer? The clay hypothesis for abiogenesis proposed by Cairns-Smith [2] or the Wachtershauser [7] hypothesis for an iron sulfur world or Mulkidjanian’s [16] hypothesis of the Zn-world theory leads to thinking about micro and nano electroporation [5,6]. Clays and pyrite are structures with local electric charges. We have shown that when cells pass across surfaces with charges separated by nanometer distances the electric fields that are produced are sufficient to cause electroporation and electrolysis induced reversible and irreversible poration of the cell membrane [20,21]. We have also shown that it is sufficient for only part of the cell membrane to be exposed to electroporation fields for electroporation to occur [5,6]. Fig. 1 illustrates the electric field that would develop across a cell membrane when the cell flows across a substrate in which two small charges with a potential difference of 0.1 V are separated by a 100-nanometer gap. Even in the absence of native charges, an electrolytic process

Mathematical analysis of a model describing the number of antibiotic resistant bacteria in a polluted river

In France, 90% of surface water suffer from antibiotic pollution that increases the number of antibiotic resistant bacteria. The first indicator of water quality is revealed by the fish quality. According to the Le Conseil Supérieur de la Pêche, only 15% of rivers in France are considered in good condition, whereas 22% are in very bad condition. The bacterial resistance to antibiotics is a public health problem as it affects humans through drinking water; the treatment of water is costly. Mathematical modeling may estimate and predict the quantity of bacteria in rivers. In this paper, we investigate properties of the mathematical model estimating the number of bacteria in a river presented by Lawrence, Mummert and Somerville. Global analysis of equilibria is presented, using a Lyapunov function. Moreover, the existence of positive periodic solutions is proven. Copyright © 2013 John Wiley & Sons, Ltd.

Strategies and molecular tools to fight antimicrobial resistance: resistome, transcriptome, and antimicrobial peptides.

The increasing number of antibiotic resistant bacteria motivates prospective research toward discovery of new antimicrobial active substances. There are, however, controversies concerning the cost-effectiveness of such research with regards to the description of new substances with novel cellular interactions, or description of new uses of existing substances to overcome resistance. Although examination of bacteria isolated from remote locations with limited exposure to humans has revealed an absence of antibiotic resistance genes, it is accepted that these genes were both abundant and diverse in ancient living organisms, as detected in DNA recovered from Pleistocene deposits (30,000 years ago). Indeed, even before the first clinical use of antibiotics more than 60 years ago, resistant organisms had been isolated. Bacteria can exhibit different strategies for resistance against antibiotics. New genetic information may lead to the modification of protein structure affecting the antibiotic carriage into the cell, enzymatic inactivation of drugs, or even modification of cellular structure interfering in the drug-bacteria interaction. There are still plenty of new genes out there in the environment that can be appropriated by putative pathogenic bacteria to resist antimicrobial agents. On the other hand, there are several natural compounds with antibiotic activity that may be used to oppose them. Antimicrobial peptides (AMPs) are molecules which are wide-spread in all forms of life, from multi-cellular organisms to bacterial cells used to interfere with microbial growth. Several AMPs have been shown to be effective against multi-drug resistant bacteria and have low propensity to resistance development, probably due to their unique mode of action, different from well-known antimicrobial drugs. These substances may interact in different ways with bacterial cell membrane, protein synthesis, protein modulation, and protein folding. The analysis of bacterial transcriptome may contribute to the understanding of microbial strategies under different environmental stresses and allows the understanding of their interaction with novel AMPs.

Interaction of silver nanoparticles with Tacaribe virus

BackgroundSilver nanoparticles possess many unique properties that make them attractive for use in biological applications. Recently they received attention when it was shown that 10 nm silver nanoparticles were bactericidal, which is promising in light of the growing number of antibiotic resistant bacteria. An area that has been largely unexplored is the interaction of nanomaterials with viruses and the possible use of silver nanoparticles as an antiviral agent.ResultsThis research focuses on evaluating the interaction of silver nanoparticles with a New World arenavirus, Tacaribe virus, to determine if they influence viral replication. Surprisingly exposing the virus to silver nanoparticles prior to infection actually facilitated virus uptake into the host cells, but the silver-treated virus had a significant reduction in viral RNA production and progeny virus release, which indicates that silver nanoparticles are capable of inhibiting arenavirus infection in vitro. The inhibition of viral replication must occur during early replication since although pre-infection treatment with silver nanoparticles is very effective, the post-infection addition of silver nanoparticles is only effective if administered within the first 2-4 hours of virus replication.ConclusionsSilver nanoparticles are capable of inhibiting a prototype arenavirus at non-toxic concentrations and effectively inhibit arenavirus replication when administered prior to viral infection or early after initial virus exposure. This suggests that the mode of action of viral neutralization by silver nanoparticles occurs during the early phases of viral replication.

Research Article: Analysis of Antimicrobial Resistance in Bacteria Found at Various Sites on Surfaces in an Urban University

The purpose of this study was to determine the extent of microbial contamination and antimicrobial resistance throughout a typical urban university environment. Determining the numbers of antibiotic resistant bacteria may provide insight into the continued development of antimicrobial resistance, and may lead to changes in university inhabitants' hygiene behaviors. In this study, samples of microorganisms were obtained from 35 surfaces at Pace University-NYC on three separate days. Samples were grown on plates of tryptic soy agar (TSA) and replicated onto control-plates, and plates containing either 100 µg/mL ampicillin, 1.0 µg/mL ciprofloxacin, or 1.0 µg/mL triclosan. The presence of bacterial growth on the drug containing plates after 24 hours indicated antimicrobial resistance. The restroom floors, toilet seats, computers, and cafeteria displayed the highest number of bacterial growth, 171, 301, 87, 143 colony forming units (CFUs) respectively. These sites also contained microorganisms displaying antimicrobial resistance to two or more of the antimicrobial agents. Resistance to triclosan, ciprofloxacin, and ampicillin were observed in 100% (±0), 97% (±0.16), and 68% (±0.47) of sample sites respectively. Finally, an additional study of hygiene behavior of 100 university inhabitants was conducted to observe a possible mechanism in the high level of distribution of drug resistant microorganisms throughout the university. The results of this study have shown that while 88% (±0.32) of inhabitants wash their hands, the time spent washing on average was 4.87 (±3.97) seconds - well below the 20 seconds recommended to sufficiently remove microorganisms from the hands.

Therapeutic potential of cationic steroid antibacterials

Antibiotics were one of the great health successes of the 20th century. Antibiotics, both naturally derived and synthetic, have resulted in huge decreases in both morbidity and mortality from bacterial infections. As a consequence, the ‘antibiotic age’ has changed public expectations about the results of infectious disease. However, this has led to high levels of inappropriate prescribing, where antibiotics may be administered to fulfil patient expectations rather than for clinical benefit. Along with unwise uses in agriculture and elsewhere, this has contributed to recent rises in numbers of antibiotic-resistant bacteria. As a result, many commentators have described this as the end of the antibiotic age and the term ‘superbug’ has entered the common vocabulary for multi-drug-resistant bacteria such as vancomycin-resistant Enterococcus, multi-drug-resistant Staphylococcus aureus and multi-drug-resistant Pseudomonas aeruginosa. In this context, an attractive approach for the development of antibacterial agents is the use of a new class of cationic steroidal compounds mimicking polymyxin activities. The permeabilization properties of these agents of the outer membranes of Gram-negative bacteria are reported in this review, as well as a discussion of literature results.

Crystal structure of UDP- N-acetylglucosamine enolpyruvyltransferase, the target of the antibiotic fosfomycin

Background The ever increasing number of antibiotic resistant bacteria has fuelled interest in the development of new antibiotics and other antibacterial agents. The major structural element of the bacterial cell wall is the heteropolymer peptidoglycan and the enzymes of peptidoglycan biosynthesis are potential targets for antibacterial agents. One such enzyme is UDP- N-acetylglucosamine enolpyruvyltransferase (EPT) which catalyzes the first committed step in peptidoglycan biosynthesis: the transfer of the enolpyruvyl moiety of phosphoenolpyruvate (PEP) to the 3-hydroxyl of UDP- N-acetylglucosamine (UDPGlcNAc). EPT is of potential pharmaceutical interest because it is inhibited by the broad spectrum antibiotic fosfomycin. Results The crystal structure of substrate-free EPT has been determined at 2.0 å resolution. The structure reveals a two-domain protein with an unusual fold (inside out α/ β barrel) which is built up from the sixfold repetition of one folding unit. The only repetitive element in the amino acid sequence is a short motif, Leu-X 3-Gly(Ala), which is responsible for the formation of hydrogen-bond interactions between the folding units. An enzyme which catalyzes a similar reaction to EPT, 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS), has a very similar structure despite an amino acid sequence identity of only 25%. To date, only these two enzymes appear to display this characteristic fold. Conclusions The present structure reflects the open conformation of the enzyme which is probably stabilized through two residues, a lysine and an arginine, located in the cleft between the domains. Binding of the negatively charged UDPGlcNAc to these residues could neutralize the repulsive force between the two domains, thereby allowing the movement of a catalytically active cysteine residue towards the cleft.

Antibiotic Resistant Bacteria in Chesapeake Bay

Water and shellfish samples were collected in Chesapeake Bay during February and March 1975, for bacteriological analyses, which included enumeration and identification of coliform bacteria resistant to multiple antibioties. Water samples were analyzed using eosin-methylene blue (EMB) agar supplemented with antibiotics. Shellfish samples were analyzed following accepted methods for examination of shellfish for coliforms and fecal coliforms. Pure cultures were isolated and evaluated for multiple drug resistance patterns using the antibiotic disk procedure to determine susceptibility. A total of 479 multiple resistant organisms was isolated. Of these, 34 were randomly picked and identified. From a compilation of the data for all the sampling sites, a trend was noted, indicating a threefold or more increase in the number of antibiotic resistant coliforms, extending up the Bay from the Chesapeake Bay Bridge north to Baltimore Harbor. The increase in number of antibiotic resistant bacteria in the vicinity of a populated area such as Baltimore supports the hypothesis that sewage effluents have a detectable influence on the water quality of Chesapeake Bay, as measured by the presence of antibiotic resistant coliform bacteria.