scholarly journals Implementation of a novel in vitro model of infection of reconstituted human epithelium for expression of virulence genes in methicillin-resistant Staphylococcus aureus strains isolated from catheter-related infections in Mexico

2014 ◽  
Vol 13 (1) ◽  
pp. 6 ◽  
Author(s):  
Gloria Paniagua-Contreras ◽  
Eric Monroy-Pérez ◽  
Felipe Vaca-Paniagua ◽  
José Rodríguez-Moctezuma ◽  
Erasmo Negrete-Abascal ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
In Vitro Model ◽  
Virulence Genes ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
Methicillin Resistant ◽  
Vitro Model

scholarly journals In Vitro Evaluation of the Activities of Telavancin, Cefazolin, and Vancomycin against Methicillin-Susceptible and Methicillin-Resistant Staphylococcus aureus in Peritoneal Dialysate

2007 ◽  
Vol 51 (12) ◽  
pp. 4521-4524 ◽  
Author(s):  
Frances L. Clouse ◽  
Laurie B. Hovde ◽  
John C. Rotschafer
Keyword(s):  
Staphylococcus Aureus ◽  
Peritoneal Dialysis ◽  
In Vitro Model ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
Dialysis Fluid ◽  
Methicillin Resistant ◽  
Peritoneal Dialysate ◽  
Peritoneal Dialysis Fluid ◽  
Vitro Model

ABSTRACT This study compared the ability of telavancin to the ability of cefazolin and vancomycin to eliminate staphylococci from peritoneal dialysis fluid by using a static in vitro model to simulate the conditions of peritoneal dialysis. The results showed that telavancin exhibited statistically significantly better kill (P < 0.05) against both methicillin-susceptible and methicillin-resistant Staphylococcus aureus.

scholarly journals Novel Daptomycin Combinations against Daptomycin-Nonsusceptible Methicillin-Resistant Staphylococcus aureus in an In Vitro Model of Simulated Endocardial Vegetations

2010 ◽  
Vol 54 (12) ◽  
pp. 5187-5192 ◽  
Author(s):  
Molly E. Steed ◽  
Celine Vidaillac ◽  
Michael J. Rybak
Keyword(s):  
Staphylococcus Aureus ◽  
Analysis Of Variance ◽  
Bactericidal Activity ◽  
In Vitro Model ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
Unique Combination ◽  
Methicillin Resistant ◽  
Vitro Model ◽  
Post Hoc

ABSTRACT Reduced susceptibility to daptomycin has been reported in patients with infections due to methicillin-resistant Staphylococcus aureus (MRSA). Although infections with daptomycin-nonsusceptible (DNS) MRSA are infrequent, optimal therapy of these strains has not been determined. We investigated the killing effects of novel antibiotic combinations with daptomycin (DAP) against two clinical DNS MRSA isolates (SA-684 and R6003) in a 72-h in vitro pharmacokinetic/pharmacodynamic (PK/PD) model with simulated endocardial vegetations (SEV). Simulated regimens included DAP at 6 mg/kg every 24 h (q24h) alone or in combination with trimethoprim-sulfamethoxazole (TMP/SMX) at 160/800 mg q12h, linezolid (LIN) at 600 mg q12h, cefepime (CEF) at 2 g q12h, and nafcillin (NAF) at 4 g q4h. Bactericidal activity was defined as a ≥3-log10 CFU/g kill. Differences in CFU/g were evaluated between 4 and 72 h by analysis of variance with the Bonferroni post hoc test. DAP MICs were 4 and 2 mg/liter for SA-684 and R6003, respectively. In the PK/PD model, DAP alone was slowly bactericidal, achieving a 3-log10 kill at 24 and 50 h for SA-684 and R6003, respectively. Against SA-684, DAP plus TMP/SMX, CEF, LIN, or NAF was bactericidal at 4, 4, 8, and 8 h, respectively, and maintained this activity for the 72-h study duration. DAP plus TMP/SMX or CEF exhibited superior killing than DAP alone against SA-684 between 4 and 72 h, and overall this was significant (P < 0.05). Against R6003, DAP plus TMP/SMX was bactericidal (8 h) and superior to DAP alone between 8 and 72 h (P < 0.001). The unique combination of DAP plus TMP/SMX was the most effective and rapidly bactericidal regimen against the two isolates tested and may provide a clinical option to treat DNS S. aureus infections.

scholarly journals Adaptation of Staphylococcus aureus in a Medium Mimicking a Diabetic Foot Environment

Toxins ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 230
Author(s):  
Cassandra Pouget ◽  
Claude-Alexandre Gustave ◽  
Christelle Ngba-Essebe ◽  
Frédéric Laurent ◽  
Emmanuel Lemichez ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Diabetic Foot ◽  
In Vitro Model ◽  
Virulence Genes ◽  
Chronic Wounds ◽  
Ring Test ◽  
Vitro Model ◽  
The Impact

Staphylococcus aureus is the most prevalent pathogen isolated from diabetic foot infections (DFIs). The purpose of this study was to evaluate its behavior in an in vitro model mimicking the conditions encountered in DFI. Four clinical S. aureus strains were cultivated for 16 weeks in a specific environment based on the wound-like medium biofilm model. The adaptation of isolates was evaluated as follows: by Caenorhabditis elegans model (to evaluate virulence); by quantitative Reverse Transcription-Polymerase Chain Reaction (qRT-PCR) (to evaluate expression of the main virulence genes); and by Biofilm Ring test® (to assess the biofilm formation). After 16 weeks, the four S. aureus had adapted their metabolism, with the development of small colony variants and the loss of b-hemolysin expression. The in vivo nematode model suggested a decrease of virulence, confirmed by qRT-PCRs, showing a significant decrease of expression of the main staphylococcal virulence genes tested, notably the toxin-encoding genes. An increased expression of genes involved in adhesion and biofilm was noted. Our data based on an in vitro model confirm the impact of environment on the adaptation switch of S. aureus to prolonged stress environmental conditions. These results contribute to explore and characterize the virulence of S. aureus in chronic wounds.

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

2020 ◽  
Vol 13 (4) ◽  
pp. 669-675
Author(s):  
Mohammad H. Gharaibeh ◽  
Mohammad S. Khalifeh ◽  
Esam M. Zattout ◽  
Luay F. Abu-Qatouseh
Keyword(s):  
Staphylococcus Aureus ◽  
Virulence Genes ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
Antimicrobial Effect ◽  
Diffusion Method ◽  
Disk Diffusion Method ◽  
Methicillin Resistant ◽  
Antimicrobial Effects ◽  
Plant Essential Oils

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.

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