scholarly journals Encapsulation and Characterization of Meropenem in Niosome Nanoparticles and Inhibitory Effects of Antibiofilm and Antibacterial on Methicillin and Vancomycin Resistant Strains of Staphylococcus Aureus

2021 ◽  
Author(s):  
Neda Jegargoshe Shirin ◽  
Tohid Piri Gharaghie ◽  
Sheida Beiranvand ◽  
Anali Riahi ◽  
Nasim Fattahi
Keyword(s):  
Staphylococcus Aureus ◽  
Inhibitory Concentration ◽  
Biofilm Growth ◽  
Genes Expression ◽  
New Strategy ◽  
Resistant Strains ◽  
Vancomycin Resistant ◽  
Hdf Cells ◽  
Microtiter Assay

Abstract Background: We aim to assess the antibacterial and anti-biofilm properties of niosome-encapsulated meropenem. Methods: After isolating S. aureus isolates and determining their microbial sensitivity, their ability to form biofilms was examined using plate microtiter assay. Various formulations of niosome-encapsulated meropenem were prepared using the thin-film hydration method, Minimum Biofilm Inhibitory Concentration (MBIC) and Minimum Inhibitory Concentration (MIC) were determined, and biofilm genes expression was examined. Drug formulations’ toxicity effect on HDF cells were determined using MTT assay.Results: Out of the 162 separated Staphylococcus aureus, 106 were resistant to methicillin. 87 MRSA isolates were vancomycin-resistant, all of which could form biofilms. The F1 formulation of neoplastic meropenem with a size of 51.3 ± 5.84 and an encapsulation index of 84.86 ± 3.14 was detected, which prevented biofilm growth with a BDI index of 69% and reduced icaD, FnbA, Ebps biofilms’ expression with p ≤0.05 in addition to reducing MBIC and MIC by 4-6 times. Interestingly, F1 formulation of neoplastic meropenem indicated cell viability over 90% at all tested concentrations. Conclusions: Results of the present study indicate that niosome-encapsulated meropenem reduces the resistance of Staphylococcus aureus MRSA to antibiotics in addition to increasing its anti-biofilm and antibiotic activity, and could prove useful as a new strategy for drug delivery.

scholarly journals Genetic Characterization of Methicillin Resistant and Sensitive, Vancomycin Intermediate Staphylococcus aureus Strains Isolated from Different Iranian Hospitals

2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
Seyed Asghar Havaei ◽  
Amir Azimian ◽  
Hosein Fazeli ◽  
Mahmood Naderi ◽  
Kiarash Ghazvini ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Genetic Analysis ◽  
Clinical Samples ◽  
Different Types ◽  
Health Care Policies ◽  
Global Health Care ◽  
Vancomycin Resistant ◽  
Epidemiological Evaluation ◽  
Mrsa Strains

Background. Global concerns have been raised due to upward trend of Vancomycin Intermediate Staphylococcus aureus (VISA) and Vancomycin Resistant Staphylococcus aureus (VRSA) reports which mean casting doubt on the absolute effectiveness of the last line of antibiotic treatment for S. aureus, vancomycin. Hence, epidemiological evaluation can improve global health care policies. Methodology. 171 Isolates of Staphylococcus aureus were collected from different types of clinical samples in selected hospitals in Isfahan, Mashhad, and Tehran, Iran. Then, they were evaluated by agar screening, disk diffusion, and MIC method to determine their resistance to vancomycin and methicillin. The isolated VISA strains were then confirmed with genetic analysis by the evaluation of mecA and vanA genes, SCCmec, agr, and spa type, and also toxin profiles. MLST was also performed. Results and Conclusion. Our data indicated that 67% of isolated S. aureus strains were resistant to methicillin. Furthermore, five isolates (2.9%) had intermediate resistance to vancomycin (VISA). In contrast to usual association of VISA with MRSA strains, we found two isolates of MSSA-VISA. Therefore, our data suggests a probable parallel growing trend of VISA towards MSSA, along with MRSA strains. However, more samples are required to confirm these primarily data. Moreover, genetic analysis of the isolated VISA strains revealed that these strains are endemic Asian clones.

scholarly journals Characterization of Passage-Selected Vancomycin-Resistant Staphylococcus aureus Strains of Diverse Parental Backgrounds

2000 ◽  
Vol 44 (2) ◽  
pp. 294-303 ◽  
Author(s):  
Richard F. Pfeltz ◽  
Vineet K. Singh ◽  
Jennifer L. Schmidt ◽  
Michael A. Batten ◽  
Christopher S. Baranyk ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Cell Walls ◽  
Methicillin Resistance ◽  
Surface Hydrophobicity ◽  
Whole Cell ◽  
Transmission Electron ◽  
Vancomycin Mics ◽  
Vancomycin Resistant ◽  
Doubling Times

ABSTRACT A series of 12 Staphylococcus aureus strains of various genetic backgrounds, methicillin resistance levels, and autolytic activities were subjected to selection for the glycopeptide-intermediate S. aureus (GISA) susceptibility phenotype on increasing concentrations of vancomycin. Six strains acquired the phenotype rapidly, two did so slowly, and four failed to do so. The vancomycin MICs for the GISA strains ranged from 4 to 16 μg/ml, were stable to 20 nonselective passages, and expressed resistance homogeneously. Neither ease of acquisition of the GISA phenotype nor the MIC attained correlated with methicillin resistance hetero- versus homogeneity or autolytic deficiency or sufficiency. Oxacillin MICs were generally unchanged between parent and GISA strains, although the mec members of both isogenic methicillin-susceptible and methicillin-resistant pairs acquired the GISA phenotype more rapidly and to higher MICs than did their susceptible counterparts. Transmission electron microscopy revealed that the GISA strains appeared normal in the absence of vancomycin but had thickened and diffuse cell walls when grown with vancomycin at one-half the MIC. Common features among GISAs were reduced doubling times, decreased lysostaphin susceptibilities, and reduced whole-cell and zymographic autolytic activities in the absence of vancomycin. This, with surface hydrophobicity differences, indicated that even in the absence of vancomycin the GISA cell walls differed from those of the parents. Autolytic activities were further reduced by the inclusion of vancomycin in whole-cell and zymographic studies. The six least vancomycin-susceptible GISA strains exhibited an increased capacity to remove vancomycin from the medium versus their parent lines. This study suggests that while some elements of the GISA phenotype are strain specific, many are common to the phenotype although their expression is influenced by genetic background. GISA strains with similar glycopeptide MICs may express individual components of the phenotype to different extents.

scholarly journals Staphylococcus aureus Infections in Malaysia: A Review of Antimicrobial Resistance and Characteristics of the Clinical Isolates, 1990–2017

Antibiotics ◽  
2019 ◽  
Vol 8 (3) ◽  
pp. 128 ◽  
Author(s):  
Ainal Mardziah Che Hamzah ◽  
Chew Chieng Yeo ◽  
Suat Moi Puah ◽  
Kek Heng Chua ◽  
Ching Hoong Chew
Keyword(s):  
Staphylococcus Aureus ◽  
Antimicrobial Resistance ◽  
Sccmec Type ◽  
Epidemiological Data ◽  
Multidrug Resistant ◽  
Clinical Isolates ◽  
Type Iv ◽  
Resistant Strains ◽  
Vancomycin Resistant ◽  
Comprehensive Surveillance

Staphylococcus aureus is an important nosocomial pathogen and its multidrug resistant strains, particularly methicillin-resistant S. aureus (MRSA), poses a serious threat to public health due to its limited therapeutic options. The increasing MRSA resistance towards vancomycin, which is the current drug of last resort, gives a great challenge to the treatment and management of MRSA infections. While vancomycin resistance among Malaysian MRSA isolates has yet to be documented, a case of vancomycin resistant S. aureus has been reported in our neighboring country, Indonesia. In this review, we present the antimicrobial resistance profiles of S. aureus clinical isolates in Malaysia with data obtained from the Malaysian National Surveillance on Antimicrobial Resistance (NSAR) reports as well as various peer-reviewed published records spanning a period of nearly three decades (1990–2017). We also review the clonal types and characteristics of Malaysian S. aureus isolates, where hospital-associated (HA) MRSA isolates tend to carry staphylococcal cassette chromosome mec (SCCmec) type III and were of sequence type (ST)239, whereas community-associated (CA) isolates are mostly SCCmec type IV/V and ST30. More comprehensive surveillance data that include molecular epidemiological data would enable further in-depth understanding of Malaysian S. aureus isolates.

scholarly journals Action ofCoriandrum sativumL. Essential Oil upon OralCandida albicansBiofilm Formation

2011 ◽  
Vol 2011 ◽  
pp. 1-9 ◽  
Author(s):  
V. F. Furletti ◽  
I. P. Teixeira ◽  
G. Obando-Pereda ◽  
R. C. Mardegan ◽  
A. Sartoratto ◽  
...  
Keyword(s):  
Essential Oil ◽  
Biofilm Formation ◽  
Plant Material ◽  
Inhibitory Concentration ◽  
Chemical Characterization ◽  
Synergistic Action ◽  
Biofilm Growth ◽  
Water Distillation ◽  
Microdilution Method

The efficacy of extracts and essential oils fromAllium tuberosum, Coriandrum sativum, Cymbopogon martini, Cymbopogon winterianus,andSantolina chamaecyparissuswas evaluated againstCandidaspp. isolates from the oral cavity of patients with periodontal disease. The most active oil was fractionated and tested againstC. albicansbiofilm formation. The oils were obtained by water-distillation and the extracts were prepared with macerated dried plant material. The Minimal Inhibitory Concentration—MIC was determined by the microdilution method. Chemical characterization of oil constituents was performed using Gas Chromatography and Mass Spectrometry (GC-MS). C. sativum activity oil upon cell and biofilm morphology was evaluated by Scanning Electron Microscopy (SEM). The best activities against planktonicCandidaspp. were observed for the essential oil and the grouped F8–10fractions fromC. sativum. The crude oil also affected the biofilm formation inC. albicanscausing a decrease in the biofilm growth. Chemical analysis of the F8–10fractions detected as major active compounds, 2-hexen-1-ol, 3-hexen-1-ol and cyclodecane. Standards of these compounds tested grouped provided a stronger activity than the oil suggesting a synergistic action from the major oil constituents. The activity ofC. sativumoil demonstrates its potential for a new natural antifungal formulation.

scholarly journals A Pilot Study of the Synergy between Two Antimicrobial Peptides and Two Common Antibiotics

Antibiotics ◽  
2019 ◽  
Vol 8 (2) ◽  
pp. 60 ◽  
Author(s):  
Franziska Kampshoff ◽  
Mark D. P. Willcox ◽  
Debarun Dutta
Keyword(s):  
Staphylococcus Aureus ◽  
Antibacterial Agents ◽  
Inhibitory Concentration ◽  
Synergistic Activity ◽  
Fractional Inhibitory Concentration ◽  
First Line ◽  
Checkerboard Assay ◽  
Resistant Strains ◽  
And Staphylococcus Aureus ◽  
Broth Dilution

Background: Frequent and unrestricted use of antibiotics has been associated with the development of antibiotic resistance by microorganisms. Thus, there is a need to find novel antibacterial agents or a combination of agents as the first line of treatment for various infections. This study aimed to investigate the synergy between antimicrobial peptide (AMP) combinations or between AMP-antibiotics combinations using two common pathogens, Pseudomonas aeruginosa and Staphylococcus aureus. Methods: The AMPs melimine, Mel4 and protamine, and antibiotics cefepime and ciprofloxacin were used in this study. The minimum inhibitory concentration (MIC) of each were evaluated against P. aeruginosa and S. aureus strains by a microtiter broth dilution. Based on the MIC of each antimicrobial agent, a checkerboard assay was performed to investigate the synergy between them, which was expressed as the fractional inhibitory concentration (FIC). Results: The combination of melimine and ciprofloxacin showed synergistic activity against antibiotic sensitive or resistant strains of P. aeruginosa and with FIC values ≤0.5. Conclusion: Combinations of AMPs and the fluoroquinolone ciprofloxacin is a promising method for reducing resistance to the fluoroquinolone of P. aeruginosa.

Delafloxacin activity against Staphylococcus aureus with reduced susceptibility or resistance to methicillin, vancomycin, daptomycin or linezolid

2020 ◽  
Vol 75 (9) ◽  
pp. 2605-2608
Author(s):  
Louis D Saravolatz ◽  
Joan M Pawlak ◽  
Corinne Wegner
Keyword(s):  
Staphylococcus Aureus ◽  
Good Activity ◽  
Limited Data ◽  
Skin Structure ◽  
Spectrum Activity ◽  
Resistant Strains ◽  
Vancomycin Resistant ◽  
Gram Negative Organisms ◽  
Susceptibility Rate ◽  
Broad Spectrum Activity

Abstract Background Delafloxacin is a recently approved anionic fluoroquinolone antibiotic with broad-spectrum activity against Gram-positive and Gram-negative organisms. The drug has been approved for patients with acute bacterial skin and skin structure infections including those caused by MRSA. There are limited data available against MRSA blood isolates (MRSABIs), vancomycin-intermediate strains (VISA), vancomycin-resistant strains (VRSA), daptomycin-non-susceptible strains (DNSSA) and linezolid-resistant Staphylococcus aureus (LRSA). Methods Antimicrobial activity of delafloxacin, levofloxacin, vancomycin, daptomycin and linezolid was determined against 110 MRSABIs, 15 VRSA, 35 VISA, 40 DNSSA and 6 LRSA. Microdilution testing using CAMHB was used to determine MIC according to CLSI guidelines. FDA breakpoints were used to determine delafloxacin susceptibility, and CLSI breakpoints were used for all other antibiotics. PCR testing for molecular markers was performed. Results Delafloxacin demonstrated activity against MRSABIs with an MIC90 of 1 mg/L and 68% susceptibility. Against the other groups the MIC90 and susceptibility were 1 mg/L and 40%, respectively, for VISA, 4 mg/L and 7% for VRSA and 1 mg/L and 38% for DNSSA. None of the LRSA isolates was susceptible to delafloxacin. Delafloxacin was active against 94% of MRSA blood isolates that were genotype SCC IVa. For MRSABIs with a levofloxacin MIC ≥8 mg/L (55/110), suggesting multiple mutations in the QRDR, delafloxacin MIC90 was 1 mg/L with a 36.4% susceptibility rate. Conclusions Delafloxacin demonstrates superior activity to levofloxacin against recent MRSA blood isolates, VISA, VRSA and DNSSA, and demonstrates good activity against blood isolates most commonly found in the community.

scholarly journals Discovery and Characterization of Potent Thiazoles versus Methicillin- and Vancomycin-Resistant Staphylococcus aureus

2014 ◽  
Vol 57 (4) ◽  
pp. 1609-1615 ◽  
Author(s):  
Haroon Mohammad ◽  
Abdelrahman S. Mayhoub ◽  
Adil Ghafoor ◽  
Muhammad Soofi ◽  
Ruba A. Alajlouni ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Vancomycin Resistant

scholarly journals Antistaphylococcal Activity of CB-181963 (CAB-175), an Experimental Parenteral Cephalosporin

2004 ◽  
Vol 48 (10) ◽  
pp. 4037-4039 ◽  
Author(s):  
Dianne B. Hoellman ◽  
Glenn A. Pankuch ◽  
Peter C. Appelbaum
Keyword(s):  
Minimum Inhibitory Concentration ◽  
Inhibitory Concentration ◽  
Methicillin Resistant ◽  
Antistaphylococcal Activity ◽  
Resistant Strains ◽  
Vancomycin Resistant

ABSTRACT Among 265 methicillin-susceptible and -resistant staphylococci, CB-181963 (CAB-175) had a 50% minimum inhibitory concentration of 2 μg/ml and a 90% minimum inhibitory concentration of 4 μg/ml. All strains except two vancomycin-resistant S. aureus and 5 vancomycin-intermediate S. aureus strains were also susceptible to vancomycin and teicoplanin, and all were susceptible to linezolid, ranbezolid, tigecycline, and quinupristin-dalfopristin. Most methicillin-resistant strains were levofloxacin resistant. CB-181963 was bactericidal against all six methicillin-resistant strains at four times the MIC after 24 h.

scholarly journals Isolation and Genetic Characterization of Vancomycin-resistant and mecC+ Methicillin-resistant Staphylococcus aureus Strains in Clinical Samples of Bojnurd, Northeastern Iran

2021 ◽  
Vol 14 (10) ◽  
Author(s):  
Parastoo Zarghami Moghaddam ◽  
Amir Azimian ◽  
Abbas Akhavan Sepahy ◽  
Alireza Iranbakhsh
Keyword(s):  
Staphylococcus Aureus ◽  
Tertiary Hospital ◽  
Clinical Samples ◽  
Spa Typing ◽  
Antibiotic Resistant ◽  
Methicillin Resistant ◽  
Alpha Hemolysin ◽  
Pcr Method ◽  
Vancomycin Resistant

Background: The emergence of antibiotic-resistant Staphylococcus aureus strains is one of the major concerns about the various staphylococcal infections. Vancomycin is one the most important effective antibiotics on staphylococcal lethal infections. To date, vancomycin-resistant strains are increasingly isolated in different parts of the world, and it is alerting. Objectives: The current study was designed to evaluate the prevalence, and antibiotic susceptibility pattern of methicillin-resistant S. aureus (MRSA) and vancomycin-resistant S. aureus (VRSA) isolates in the main tertiary hospital of Bojnurd, Iran. Methods: S. aureus isolates were collected from different clinical samples in Imam Reza Hospital of Bojnurd. After identification of isolates through using conventional methods, they were evaluated by agar screening, disk diffusion, and minimum inhibitory concentration (MIC) methods to determine resistance to vancomycin and methicillin. We also performed polymerase chain reaction (PCR) for the detection of mecA, mecC, vanA, and vanB genes. After confirmation of vancomycin resistance, genetic analysis was performed using SCCmec, agr, and spa typing, and multilocus sequence typing (MLST) methods on VRSA isolates. Results: We found four vancomycin-resistant isolates (1.29%). Also, 75% of isolates were resistant to cefoxitin. Using the PCR method, mecA was found in 73%, mecC in 0.64%, and vanA in 1.29% of isolates. Interestingly, we found two mecC positive isolates in MRSA isolates. The alpha-hemolysin (81.81%) and enterotoxin C (27%) had the highest and lowest toxins percentage, respectively. Among mecA positive isolates, SCCmecIV (37%), SCCmecIII (31.27%), SCCmecI (14%), SCCmecII (11%), and SCCmecV (5.7%) were the most prevalent SCCmec types, respectively. It should be noted that the two mecC positive isolates belonged to SCCmecXI. AgrI (76.29%) was the highest agr type. We recognized t037 as the dominant spa type, and ST239, ST6, ST97, and ST8 were found in VRSA isolates. Conclusions: In our study, the frequency of mecA genes in MRSA isolates was very high. It seems that the resistant isolates belonged to endemic clones of Iran.

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