Methicillin-resistant Staphylococcus Aureus Pathogens Research Articles

Synthesis, Anti-Bacterial and Molecular Docking Studies of Arylated Butyl 2-Bromoisonicotinate Against Clinical Isolates of ESBL-Producing Escherichia coli ST405 and Methicillin-Resistant Staphylococcus aureus.

Global public health concerns include the emergence and spread of methicillin-resistant Staphylococcus aureus (MRSA) and extended-spectrum beta-lactamase Escherichia coli (ESBL-E. coli). These pathogens cause infections that are difficult to treat, which can have fatal outcomes and require lengthy hospital stays. As a result, we created butyl 2-bromoisonicotinate and tested its antibacterial effectiveness against the ESBL-E. coli ST 405 and MRSA pathogens. Natural product discovery is complemented by synthetic compound synthesis because of the latter's potential for superior characteristics, target specificity, scalability, intellectual advantages, and chemical diversity. Because of this, the potential for discovering new medicinal compounds is increased, and the constraints placed on natural sources are overcome. Natural items are tough to obtain since they are hard to isolate and synthesize. Therefore, modern science is actively searching for small molecules as therapeutic agents by applying sustainable techniques that can be commercialized. Two patients' blood samples were taken, and the BACTEC/Alert system was used to process them. On blood and MacConkey agar, the positive samples were subcultured and incubated aerobically at 37 °C. Using the VITEK 2 compact system, the isolates were subjected to isolate identification and MIC. MLST of the ESBL-E. coli was performed by PCR. Additionally, Fischer esterification was used to create butyl 2-bromoisonicotinate in excellent yields. A commercially available palladium catalyst was then used to arylate the compound, resulting in medium to good yields of arylated butyl 2-bromoisonicotinates. Using the agar well diffusion assay and the micro-broth dilution method, we assessed the in-vitro activities of the synthesized molecules (3, 5a-h) against clinically isolated ESBL-E. coli ST405, and MRSA. A molecular operating environment was used to carry out in silico validation of the synthesized compounds' binding to the active site and to evaluate the stability of their molecular interactions with the target E. coli 2Y2T protein. MRSA and ESBL-producing E. coli were identified as the two clinical isolates. While MRSA was also resistant to beta-lactam drugs and least resistant to vancomycin, ESBL-producing E. coli belonged to ST405 and was resistant to cephalosporins and sensitive to carbapenems. Good yields of the desired compounds were produced by our effective and economical synthesis. By using a micro-broth dilution assay, the Molecules (3, 5a, and 5d) were most effective against both resistant strains. The Molecules (3, 5a, 5b, and 5d) also displayed good binding energies. The butyl 2-bromoisonicotinate displayed antibacterial efficacy against ESBL-producing E. coli ST405 and MRSA strains. After the in-vivo trial, this substance might offer an alternative therapeutic option.

Hybrid Biomimetic Membrane Coated Particles-Mediated Bacterial Ferroptosis for Acute MRSA Pneumonia.

Acute methicillin resistant Staphylococcus aureus (MRSA) pneumonia is one of the most frequently seen lung infection diseases with high morbidity and mortality. It is urgent to explore an efficient antibacterial strategy owing to the increase of drug resistance, virulence, and pathogenicity of MRSA. It was found that Fe3O4 can induce ferroptosis in MRSA, but its effect was inhibited by glutathione (GSH) to a certain extent, while cinnamaldehyde (CA) can enhance ferroptosis by consuming GSH. As a bacterial quorum sensing (QS) inhibitor, CA can suppress the QS system and further exert its antibacterial and antibiofilm effects. Here, we developed an Fe3O4-based ferroptosis inducer to promote ferroptosis in MRSA, interrupt the QS, destroy biofilm, and thus effectively treat acute MRSA pneumonia. We used sodium alginate (SA) to wrap Fe3O4 and CA to form particles, and then coated the surface with a hybrid biomimetic membrane composed of an erythrocyte membrane and platelet membrane to obtain lung targeted antibacterial particles (mFe-CA). Under ultrasonic (US) stimulation, mFe-CA can efficiently release Fe3O4 and CA, thereby synergically inducing MRSA death with the characteristics of ferroptosis, including mass ROS production, lipid peroxidation, GSH depletion, and respiratory chain suppression. Furthermore, mFe-CA + US can inhibit the QS system, remove biofilms, and reduce strain virulence. In the mouse model of MRSA pneumonia, mFe-CA + US treatment markedly advanced the survival rate of the mice, reduced the bacterial load in the lungs, and alleviated the inflammatory damage, but there was no obvious toxicity. This study proposes an antibacterial substitute to induce ferroptosis of MRSA, which may provide a foreground for overcoming microbial drug resistance and fighting biofilm-associated infections and also provides a target and theoretical basis for clinical treatment of acute MRSA pneumonia.

The identification of bacteria from human microbiota that inhibit the growth of Methicillin-Resistant Staphylococcus aureus

Methicillin-Resistant Staphylococcus aureus (MRSA) is an antibiotic-resistant bacterium and a major cause of preventable illness and death. To combat MRSA and other antibiotic-resistant pathogens, alternatives to small molecule therapeutics targeting essential biological pathways of bacteria must be identified. Staphylococci, including MRSA strains, can exist as part of the human microbiota, competing for resources and space with other microorganisms. Here, we sought to identify bacteria from the human microbiota capable of killing or inhibiting the growth of MRSA. Swabs of the nostrils and skin of two individuals were collected, one being a natural MRSA carrier, and bacteria were isolated from these samples. Of these isolates, eight showed to inhibit the growth of a MRSA strain when cross streaking. To identify these bacteria, a portion of the 16s rRNA gene of these bacteria was sequenced and compared to known bacteria in the genbank database using BLAST. Of the eight isolates, three distinct bacterial species were identified: Acinetobacter baumannii, Bacillus aerius, and Staphylococcus epidermidis. Following the identification of these bacteria, we sought to determine the mechanism of inhibition. Cell lysates and extracellular material of these inhibitory bacteria were used in a disk diffusion assay which showed no observable zones of inhibition toward MRSA. This suggests that these bacteria may need to be viable and/or directly contact MRSA to mediate the inhibition of growth. To test this hypothesis, phase-contrast microscopy of co-cultured bacteria was used. While results here suggested that B. aerius directly interfered with the ability of MRSA to replicate, future studies using time-lapse microscopy of fluorescent strains of these microbes should produce data that can be more clearly interpreted.

Targeting multidrug resistant Staphylococcus infections with bacterial histidine kinase inhibitors.

The emergence of drug-resistant bacteria, such as methicillin-resistant Staphylococcus aureus (MRSA), which are not susceptible to current antibiotics has necessitated the development of novel approaches and targets to tackle this growing challenge. Bacterial two-component systems (TCSs) play a central role in the adaptative response of bacteria to their ever-changing environment. They are linked to antibiotic resistance and bacterial virulence making the proteins of the TCSs, histidine kinases and response regulators, attractive for the development of novel antibacterial drugs. Here, we developed a suite of maleimide-based compounds that we evaluated against a model histidine kinase, HK853, in vitro and in silico. The most potent leads were then assessed for their ability to decrease the pathogenicity and virulence of MRSA, resulting in the identification of a molecule that decreased the lesion size caused by a methicillin-resistant S. aureus skin infection by 65% in a murine model.

Identification and Characterization of a Potential Antimicrobial Peptide Isolated from Soil Brevibacillus sp. WUL10 and Its Activity against MRSA Pathogens.

Methicillin-resistant Staphylococcus aureus (MRSA) is a severe threat to public health globally. The development of novel agents has encountered the repeated mechanism of drug resistance. This study aimed to investigate an anti-MRSA substance isolated from a promising soil bacterium. The result showed that an isolate (WUL10) was in the Brevibacillus genus. The minimum inhibitory concentration (MIC) of the purified substance was 1 µg/mL against S. aureus TISTR 517 and MRSA strains. This substance showed the bactericidal effect at the concentration of 1–2 µg/mL against these bacterial indicators. The activity of the substance retained more than 95% when encountering high temperatures and a wide range of pH, but it was sensitive to proteolytic enzymes and SDS. It was identified as a novel antimicrobial peptide (KVLVKYLGGLLKLAALMV-COOH) with the predicted structure of α-helix. The substance could rupture the cell wall of the tested pathogen. MIC and MBC of the synthesized peptide were 16 and 64 µg/mL, respectively. The difference in the activity between the isolated and synthetic peptides might be from the synergistic effects of other AMPs in the purified substance. This novel AMP would provide an advantage for further development of anti-MRSA substances to manage the situation of antibiotic resistance.

Lacticaseibacillus spp.; Probiotic candidates from Palmyra palm sugar possesses antimicrobial and anti-biofilm activities against methicillin-resistant Staphylococcus aureus.

Background and Aim:Probiotics are beneficial microorganisms that play important roles by adhering to the gut and producing antimicrobial substances to inhibit pathogens. The objective of this study was to isolate and characterize the probiotic lactic acid bacteria (LAB) from Palmyra palm sugar, which can produce antimicrobial compounds against methicillin-resistant Staphylococcus aureus (MRSA), a new zoonotic and food-borne pathogens.Materials and Methods:Twenty-six LAB isolates were isolated from 30 Palmyra palm sugar samples. Three selected LAB were further characterized as probiotics. In addition, the antibacterial and anti-biofilm-forming activities of the probiotics’ culture supernatants against MRSA and food-borne pathogens were investigated. Finally, the selected probiotics were identified by aligning 16S rRNA sequences.Results:The three confirmed probiotics, WU 0904, WU 2302, and WU 2503, showed strong antibacterial activities against S. aureus, MRSA, Escherichia coli O157:H7, and Listeria monocytogenes, as measured by a broth microdilution assay. Among the LAB isolates, 82.22-86.58%, 91.83-96.06%, and 64.35-74.93% exhibited resistance to low pH, pancreatin treatment, and bile salts, respectively. It was found that 59.46% and 83.33% auto-aggregation was observed in 2 and 24 h, respectively. Moreover, 50.25-57.24% adhesion was detected after the incubation of the bacterial cells to Caco-2 cells.. Biofilm inhibition (82.81-87.24%) was detected after the treatment of MRSA with the culture supernatants, when compared with that to the control. By the alignment of 16S rRNA sequences, the isolate WU 2302 was identified as Lacticaseibacillus spp. with 98.82% homology when compared to the GenBank database.Conclusion:This study indicates that isolated probiotics can produce antimicrobial compounds against MRSA and food-borne pathogens. The obtained results strongly suggest that these probiotics are promising candidates for pharmaceutical products.

Sensitizing Staphylococcus aureus to antibacterial agents by decoding and blocking the lipid flippase MprF.

The pandemic of antibiotic resistance represents a major human health threat demanding new antimicrobial strategies. Multiple peptide resistance factor (MprF) is the synthase and flippase of the phospholipid lysyl-phosphatidylglycerol that increases virulence and resistance of methicillin-resistant Staphylococcus aureus (MRSA) and other pathogens to cationic host defense peptides and antibiotics. With the aim to design MprF inhibitors that could sensitize MRSA to antimicrobial agents and support the clearance of staphylococcal infections with minimal selection pressure, we developed MprF-targeting monoclonal antibodies, which bound and blocked the MprF flippase subunit. Antibody M-C7.1 targeted a specific loop in the flippase domain that proved to be exposed at both sides of the bacterial membrane, thereby enhancing the mechanistic understanding of bacterial lipid translocation. M-C7.1 rendered MRSA susceptible to host antimicrobial peptides and antibiotics such as daptomycin, and it impaired MRSA survival in human phagocytes. Thus, MprF inhibitors are recommended for new antivirulence approaches against MRSA and other bacterial pathogens.

In vitro Activity of Contezolid Against Methicillin-Resistant Staphylococcus aureus, Vancomycin-Resistant Enterococcus, and Strains With Linezolid Resistance Genes From China.

Contezolid is a novel oxazolidinone, which exhibits potent activity against gram-positive bacteria, including methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant Enterococcus (VRE), and penicillin-resistant Streptococcus pneumoniae (PRSP). In this study, the in vitro activity of contezolid was compared with linezolid (LZD), tigecycline (TGC), teicoplanin (TEC), vancomycin (VA), daptomycin (DAP), and florfenicol (FFC) against MRSA and VRE strains isolated from China. Contezolid revealed considerable activity against MRSA and VRE isolates with MIC90 values of 0.5 and 1.0 μg/mL, respectively. For VRE strains with different resistance genotypes, including vanA- and vanM-type strains, contezolid did not exhibit significantly differential antibacterial activity. Furthermore, the antimicrobial activity of contezolid is similar to or slightly better than that of linezolid against MRSA and VRE strains. Subsequently, the activity of contezolid was tested against strains carrying linezolid resistance genes, including Staphylococcus capitis carrying cfr gene and Enterococcus faecalis carrying optrA gene. The results showed that contezolid exhibited similar antimicrobial efficacy to linezolid against strains with linezolid resistance genes. In general, contezolid may have potential benefits to treat the infections caused by MRSA and VRE pathogens.

Comparison of Antivirulence Activities of Black Ginseng against Methicillin-Resistant Staphylococcus aureus According to the Number of Repeated Steaming and Drying Cycles.

Korean ginseng has been widely used in Eastern medicine for thousands of years. The contents of the compounds in ginseng roots change depending on the amount of steaming and drying, and the drying method used. Black ginseng (BG) is the Korean ginseng processed by repeated steaming and drying. In this study, 5-year-old fresh Korean ginseng roots were steamed and dried 3 or 5 times, and we investigated how many cycles of steaming and drying are preferable for antivirulence activities against methicillin-resistant Staphylococcus aureus (MRSA). As a result, the antivirulence activities was increased by the treatment of BG that was steamed and dried three times, and the effect was further increased by five-time processed BG. Moreover, an ELISA showed that the TNF-α production of RAW264.7 cells stimulated by MRSA supernatants was inhibited by subinhibitory concentrations of BG extract. The expression of Hla, staphylococcal enterotoxin A (SEA), and staphylococcal enterotoxin B (SEB), an important virulence factor in the pathogenicity of MRSA, was found to decrease when bacterial cells were treated with BG extract. The antivirulence activities of BG were not simply due to pathogen growth inhibition; the BG extract was shown to decrease agrA, hla, sea, and seb expression in MRSA. Therefore, BG strongly reduces the secretion of the virulence factors produced by Staphylococcus aureus, suggesting that a BG-based structure may be used for the development of drugs aimed at staphylococcal virulence-related exoproteins. This study suggests that BG could be used as a promising natural compound in the food and pharmaceutical industry.

Potential antimicrobial effect of plant essential oils and virulence genes expression in methicillin-resistant Staphylococcus aureus isolates.

Aim:This study aimed to investigate the antibacterial efficacy of eight commercially available essential oil (EO) blends and characterize the effect on the expression of some virulence genes against methicillin-resistant Staphylococcus aureus (MRSA).Materials and Methods:In vitro evaluation of the antimicrobial effects of oils against MRSA was performed using the disk diffusion method and by measuring the minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC). The EOs (A-F) were contained (β-pinene, carvacrol, carvone, dimethyl trisulfide, linalool, limonene, menthol, monoterpene hydrocarbons, and thymol) in different amounts. In addition, a real-time polymerase chain reaction was also used to determine the gene expression of the virulence genes (intercellular adhesion cluster [ica]-9, ica-15, and RNA III) against MRSA (ATCC 43300) after treatment with selected oils.Results:Among the eight EOs evaluated, EO (D), (E), and (A) showed, in general, the greatest antimicrobial activity against MRSA. EO at 1/3 MIC has effectively down-regulated ica-9 and ica-15 of MRSA by 17.83 and 4.94 folds, respectively. Meanwhile, EO (A) has effectively down-regulated RNAIII by 3.74 folds. Our results indicated that some of the EOs exhibit promising antimicrobial effects against MRSA isolates. Moreover, the results of the analyzed virulence genes related to the pathogenicity of MRSA were down-regulated at the sub-MIC concentrations of EOs, indicated that EOs could be successfully used to suppress the virulence factors and, consequently, decreased the pathogenicity of MRSA.Conclusion:These encouraging results indicate that some of the EOs used in this study can be utilized as a natural antibiotic for the treatment of MRSA disease.

Prevalence and antibiotic susceptibility of methicillin resistant <i>Staphylococcus aureus</i> (MRSA) isolated from bovine mastitis in settled Fulani herds in Kaduna State

A study was conducted to determine the prevalence and antibiotic resistance of methicillin resistant Staphylococcus aureus (MRSA) from bovine mastitis in settled Fulani herds in Kaduna state. Three hundred and sixty milk samples randomly collected from selected herds in Kaduna South, Igabi, Lere, Sabon-Gari, Giwa and Zaria were examined. The prevalence of mastitis at cow level was 26.9%, out of which 3.1% and 23.9% were clinical and subclinical mastitis, respectively. The prevalence of both S. aureus and MRSA were 15.3% and 7.8 % respectively. Significant proportion (42.9%) of the MRSA were isolated from cases of mastitis (P<0.05). Very high percentages of MRSA were resistance to penicillin (100.0%), amoxicillin (89.3%), ampicillin (89.3%), tetracycline (85.7%) and erythromycin (71.1%). The multiple drug resistance indices of the MRSA strains revealed that all the MRSA strains were resistant to 5 or more antibiotics tested; 6 (21.4%) strains were resistant to 6 antibiotics, 6 (21.4%) were resistant to 7 antibiotics, 8 (28.6%) were resistant 8 antibiotics and 4 (14.3%) were resistant to 9 antibiotics, while 19 (67.9%) exhibited the extensive drug classification pattern. The MIC values of the antibiotics showed that all (100%) have values greater than 256 μg/mL against oxacillin while 15 (53.6%) have values greater than 256 μg/mL against vancomycin, respectively. Nineteen (67.9%) of the MRSA isolates tested for PBP2a gave strongly positive (3+ to 4+) reactions in the Latex Agglutination Test, 5 (1.9%) were weakly positive (1+) in the Latex Agglutination Test while 4 (14.3%) were negative. The occurrence of MRSA in bovine mastitis is of public health concern due to difficulty in treatment of staphylococcal diseases and possible transmission of resistant pathogens to humans. Therefore, continuous monitoring and surveillance of antibiotic resistance pathogens, good husbandry practices, culling of infected cows and pasteurization of milk to eliminate MRSA and other pathogens are recommendedKeywords: Prevalence, antibiotic susceptibility, MRSA, Bovine mastitis, cow milk, multi drug resistance, extensive drug resistance (XDR), minimum inhibitor concentration, Penicillin Binding Protein 2a

The Pathogenicity and Transcriptome Analysis of Methicillin-Resistant Staphylococcus aureus in Response to Water Extract of Galla chinensis

Aim Antibiotic abuse contributes to the emergence of methicillin-resistant Staphylococcus aureus (MRSA). It is increasingly important to screen new antimicrobial agents for the management of MRSA infections. G. chinensis, a nontoxic Chinese herbal medicine, is considered a potential antibacterial agent. The aim of this study was to investigate the bactericidal effects of the aqueous extracts of G. chinensis on MRSA. The potential mechanisms of G. chinensis aqueous extract inhibition of the pathogenicity of MRSA in vivo are also discussed. Methods G. chinensis aqueous extract was prepared and its antimicrobial activities were examined by determining its minimum inhibitory concentration (MIC). Biofilm biomass was determined by scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM). RNA sequencing (RNA-seq) was used to evaluate differentially expressed functional pathways in MRSA treated with G. chinensis aqueous extract. We validated the role of G. chinensis aqueous extract in the invasive ability and pathogenicity of MRSA in vivo using a rat infectious model. Results The results indicated that MRSA was sensitive to the G. chinensis aqueous extracts at concentration of 31.25μg/mL. G. chinensis extract led to a reduction in dextran-dependent aggregation and biofilm formation in MRSA. Based on the transcriptome analysis, G. chinensis aqueous extracts significantly downregulated the gene expression related to biofilm formation and carbohydrate metabolism. G. chinensis aqueous extract inhibited the invasive ability and the pathogenicity of MRSA in vivo. Conclusion The antimicrobial properties of G. chinensis aqueous extract are likely related to its modulation of MRSA biofilm formation and carbohydrate metabolism. G. chinensis aqueous extract is a promising supplementary therapy to lessen or eliminate the use of antibiotics and is a potential tool for the management of MRSA infections.

Nitrogen-Doped Carbon Quantum Dots for Preventing Biofilm Formation and Eradicating Drug-Resistant Bacteria Infection.

The development of novel antimicrobial agents is a top priority in the fight against drug-resistant bacteria. Here, we synthesized a green nanoantibiotic, nitrogen-doped carbon quantum dots (N-CQDs) from bis-quaternary ammonium salt (BQAS) as carbon and nitrogen sources. The as-obtained N-CQDs possess high antibacterial activity (>99%) against both methicillin-resistant Staphylococcus aureus (MRSA) and Ampicillin-resistant Escherichia coli bacteria in vitro than some known clinical antibiotics (vancomycin and gentamicin). The N-CQDs can kill MRSA pathogens without inducing resistance, prevent biofilm formation and eliminate established biofilm and persister cells. The treatment of N-CQDs can significantly reduce the amount of bacteria on the infected tissue and accelerate wound healing. The N-CQDs are positively charged, thus enabling them to interact with bacterial cell membrane through electrostatic interaction, leading to severe damage and an increased permeability of the cell membrane, which further promotes the penetration of N-CQDs into the membrane and induces the degradation of DNA by N-CQDs generated reactive oxygen species. The N-CQDs also play a role in obstructing the intracellular metabolic pathways of MRSA. The overall data demonstrate the green nanoantibiotic as an excellent eradicator of biofilm and persister cells as well as a promising antibacterial candidate for treating infections induced by drug-resistant bacteria.

Antimicrobial resistance, virulence genes profiling and molecular relatedness of methicillin-resistant Staphylococcus aureus strains isolated from hospitalized patients in Guangdong Province, China.

PurposeThe main objective of this study was to decipher the prevalence, antimicrobial resistance, major virulence genes and the molecular characteristics of methicillin-resistant Staphylococcus aureus (MRSA) isolated from different clinical sources in southern China.Materials and methodsThe present study was performed on 187 non-duplicate S. aureus clinical isolates collected from three tertiary hospitals in Guangdong Province, China, 2010–2016. Antimicrobial susceptibility testing was performed by the disk diffusion method and by measuring the minimum inhibitory concentration. Screening for resistance and virulence genes was performed. Clonal relatedness was determined using various molecular typing methods such as multilocus sequence typing, spa and staphylococcal chromosomal cassette mec (SCCmec) typing. Whole genome sequencing was performed for three selected isolates.ResultsOut of 187 isolates, 103 (55%) were identified as MRSA. The highest prevalence rate was found among the skin and soft tissue infection (SSTI) samples (58/103), followed by sputum samples (25/103), blood stream infection samples (15/103) and others (5/103). Antimicrobial susceptibility results revealed high resistance rates for erythromycin (64.1%), clindamycin (48.5%), gentamicin (36.9%) and ciprofloxacin (33.98%). All isolates were susceptible to vancomycin. Resistance genes and mutation detected were as follows: aac(6’)-aph(2”) (24.3%), dfrG (10.7%), rpoB (21.4%), cfr (0%), fexA (1.94%), gyrA (35.92%), gyrB (0.97%), grlA (20.4%), grlB (10.68%), ermA (21.4%), ermB (18.44%), ermC (21.4%) and lnuA (18.44%). Profiling of virulence genes revealed the following: sea (11.7%), seb (21.4%), sec (0.97%), sed (0.97%), hla (86.41%), hlb (17.48%), hlg (10.68%), hld (53.4%), Tsst-1 (3.9%) and pvl (27.2%). Clonal relatedness showed that ST239-SCCmecA III-t37 clone was the most prevalent clone.ConclusionOur study elucidated the prevalence, antibiotic resistance, pathogenicity and molecular characteristics of MRSA isolated from various clinical sources in Guangdong, China. We found that the infectious rate of MRSA was higher among SSTI than other sources. The most predominant genotype was ST239-SCCmecA III-t37 clone, indicating that ST239-t30 clone which was previously predominant had been replaced by a new clone.

Methicillin-Resistant Staphylococcus aureus and Other Multidrug-Resistant Colonizations/Infections in an Intensive Care Unit: Predictive Factors.

Methicillin-resistant Staphylococcus aureus (MRSA) is the most prevalent pathogen causing nosocomial infections in hospitals and health centers. This work is an effort to understand the epidemiology of MRSA and other multidrug-resistant pathogens in an intensive care unit (ICU) and to analyze characteristics that might determine the risk of MRSA colonization/infection in this unit. An observational, 1-year prospective longitudinal study was conducted to obtain information about MRSA and other multidrug-resistant colonizations/infections. The study was conducted with ICU patients with an artificial airway. Data were obtained from the National Study of the Control of Nosocomial Infections in Intensive Care Units database. MRSA colonization was highly prevalent (33%); however, other pathogens like gram(-) Bacillus showed a higher infectious potency. Acute Physiology and Chronic Health Evaluation (APACHE-II) score >15 and hospital stay of >4 days were the main variables that significantly predicted the risk of developing MRSA colonization ( p < .001 in both cases). Moreover, the presence of MRSA increased the risk of developing a second multidrug-resistant colonization/infection, especially with methicillin-resistant Pseudomona. The high prevalence of MRSA emphasizes the need to continue studying risk factors for MRSA colonization/infection, which may allow early identification of this pathogen. Therefore, we propose the use of the APACHE-II score and length of hospital stay to predict increased risk of MRSA colonization. Awareness of the heightened risk in particular patients could lead to early detection and prevention.

One-Pot Facile Green Synthesis of Silver Nanoparticles Using Seed Extract of Phoenix dactylifera and Their Bactericidal Potential against MRSA.

Due to the great economic, health, and medicinal importance, Phoenix dactylifera seeds were chosen for the synthesis of silver nanoparticles (AgNPs) because of their ecofriendly, nonhazardous, cost effectiveness advancement over physical and chemical methods, as green methods are safe, one step, and simple and did not require any chemical reducing and stabilizing agents. The green synthesized AgNPs were characterized by UV-Vis spectroscopy, SEM, HR-TEM, and DLS. Further, the bactericidal activity of synthesized AgNPs against Methicillin-resistant Staphylococcus aureus (MRSA) was investigated by determining MIC/MBC, agar diffusion methods, and electron microscopy. TEM images of the so-formed AgNPs revealed that the NPs were spherical in shape, with a size range of 14–30 nm. The MIC and MBC of AgNPs for MRSA were found to be 10.67±0.94 and 17.33±1.89 μg/ml, respectively. The antibacterial activities were found to be increased with the increasing concentration of AgNPs. The zone of inhibition was greater (24mm) at highest concentrations (500μg/ml) of AgNPs, while smaller (11mm) at lowest concentrations (7.8μg/ml). The SEM images of treated MRSA cells showed wrinkled and damaged cell wall, indicating the disruption and disorganization of membrane. HR-TEM analysis exhibits extensive injury and complete disintegration of cell wall and membrane. Large translucent zones have been seen in the cytoplasm, due to either localized or complete separation of the cell membrane from the cell wall. Overall, these results indicate that green synthesized AgNPs should be considered as an effective treatment and prevention option for the medical devises related infections caused by deadly MRSA and other drug resistant pathogens.

Bacterial pathogens associated with external ocular infections alongside eminent proportion of multidrug resistant isolates at the University of Gondar Hospital, northwest Ethiopia

BackgroundExternal ocular infection is a public health problem in Ethiopia. The aim of this study was to determine the prevalence and antimicrobial susceptibility pattern of external ocular bacterial infections.MethodsA cross sectional study was conducted at the University of Gondar Hospital among patients seeking health services at the Department of Ophthalmology from January to April, 2016. All patients with suspected external ocular infections were examined under slit lamp microscope. External ocular samples were collected using aseptic techniques. All samples were investigated by culture and bacteria were identified using standard methods. Drug susceptibility test was done using the Kirby-Bauer Disk diffusion method according to the guidelines of Clinical and Laboratory Standard Institute (CLSI).ResultA total of 312 samples were collected and 58.3% were culture positive. The proportion of Gram positive bacterial pathogens was (88%), and Staphylococcus aureus (50.3%) was the predominantly isolated pathogen, followed by Coagulase negative staphylococci (CoNS) (33.5%) and Klebsiella species (4.7%). Conjunctivitis was the dominant clinical feature, but a high positive result for bacterial pathogens was observed among patients with dacryocystitis cases. The Gram positive bacterial isolates were susceptible to ciprofloxacin, chloramphinicol, amoxicillin-clavulanate and ceftriaxone. However, 65% of these Gram positive bacterial pathogens showed resistance to penicillin, ampicillin and amoxicillin. The prevalence of methicillin-resistant Staphylococcus aureus (MRSA) infection was 24% and multidrug resistance (MDR) was observed in 87% of the isolated bacteria.ConclusionConjunctivitis was the dominant ophthalmic disease followed by blepharitis. The dominant bacteria species was S. aureus and MRSA infection is increasingly prevalent. The overall MDR bacterial pathogen proportion was very high. The high prevalence of MRSA and MDR bacterial pathogens dictate the need for effective prevention as important as for therapies.

Particle engineering for intracellular delivery of vancomycin to methicillin-resistant Staphylococcus aureus (MRSA)-infected macrophages

Methicillin-resistant Staphylococcus aureus (MRSA) infection is a serious threat to the public health. MRSA is particularly difficult to treat when it invades host cells and survive inside the cells. Although vancomycin is active against MRSA, it does not effectively kill intracellular MRSA due to the molecular size and polarity that limit its cellular uptake. To overcome poor intracellular delivery of vancomycin, we developed a particle formulation (PpZEV) based on a blend of polymers with distinct functions: (i) poly(lactic-co-glycolic acid) (PLGA, P) serving as the main delivery platform, (ii) polyethylene glycol-PLGA conjugate (PEG-PLGA, p) to help maintain an appropriate level of polarity for timely release of vancomycin, (iii) Eudragit E100 (a copolymer based on dimethylaminoethyl methacrylate, butyl methacrylate and methyl methacrylate, E) to enhance vancomycin encapsulation, and (iv) a chitosan derivative called ZWC (Z) to trigger pH-sensitive drug release. PpZEV NPs were preferentially taken up by the macrophages due to its size (500–1000nm) and facilitated vancomycin delivery to the intracellular pathogens. Accordingly, PpZEV NPs showed better antimicrobial activity than free vancomycin against intracellular MRSA and other intracellular pathogens. When administered intravenously, PpZEV NPs rapidly accumulated in the liver and spleen, the target organs of intracellular infection. Therefore, PpZEV NPs is a promising carrier of vancomycin for the treatment of intracellular MRSA infection.

Evaluation of the eazyplex MRSA assay for the rapid detection of Staphylococcus aureus in pleural and synovial fluid

Loop-mediated isothermal amplification (LAMP) is a simple and sensitive technique for rapid microbiological diagnosis. The aim of this study was to evaluate the analytical and diagnostic performance of the LAMP eazyplex MRSA test for the direct detection and differentiation of methicillin-susceptible (MSSA) and methicillin-resistant Staphylococcus aureus (MRSA) in synovial/pleural fluid. Analytical validation included the determination of the limit of detection (LoD) and analytical specificity of the eazyplex MRSA test. A diagnostic evaluation of the eazyplex test against bacterial culture was performed on routine pleural/synovial samples collected prospectively from patients aged less than 18 years with complicated pneumonia with empyema or arthritis admitted to the Children's Hospital Sant Joan de Déu in Barcelona, Spain, between April 2015 and May 2016. The new system appropriately detected a quality control panel of clinical samples with DNA of MSSA, MRSA, and other pathogens. The LoD was established at 6.4×103 CFU/ml for S. aureus and 1.0×104 CFU/ml for MRSA. Diagnostic validation of the eazyplex MRSA assay was performed on 51 prospective clinical invasive samples, resulting in sensitivity and specificity values of 83.3% and 97.8%, respectively, for S. aureus detection. The mean turnaround time was 70min. The eazyplex MRSA assay was found to be a useful test for the rapid detection of S. aureus in invasive samples such as pleural/synovial fluid.

Isolation of MRSA Strains from Hospital Environment in Benghazi City, Libya

Methicillin-resistant Staphylococcus aureus (MRSA) is an important cause of healthcare-associated infections, where healthcare workers (HCWs) are vectors of transmission. In addition to exposure to healthcare workers who may be as carriers, exposure to contaminated rooms can also be a risk factor. The hospital environment, especially surfaces, represents a secondary reservoir for pathogens such as S. aureus, and represent a challenge to infection control practices in most countries. This study aimed to explore the prevalence of MRSA in hospitals of Benghazi, Libya, Sounding the alarm of the presence of large hospitals infection in Benghazi and probably are in the grip of endemic problems with resistant organisms. Methods: The 395 swabs were collected from hospital surfaces such as surfaces of frequently handled items (beds, sinks, door handles, floors, and table surfaces). The surface swabs were collected at the different wards of the hospital Medical units, ICU and HCWs rooms. Results: Highest rate was in ICU followed by medical units and dialysis wards (9.5%, 7.8%, and 5% respectively ). Conclusion: MRSA strains prevalence in Benghazi City. was high and this may be the case for other hospitals in Libya. A sound surveillance program of nosocomial infections is urgently needed to reduce the incidence of infections due to MRSA and other antimicrobial-resistant pathogens in Libyan hospitals.