Minimum Inhibitory Concentrations of Vancomycin and Daptomycin Against Methicillin-resistant Staphylococcus Aureus Isolated from Various Clinical Specimens: A Study from South India

Abstract

Background Staphylococci are Gram-positive cocci arranged in clusters. They are colonized in humans and animals. Also, Staphylococcus aureus (S. aureus) is frequently associated with various superficial to deep-seated infections in humans. Due to the potential for easy transmission, Staphylococci are associated with both hospital-acquired and community-associated infections. Strains of S. aureus resistant to methicillin (MRSA) pose treatment challenges. In such cases, vancomycin is the treatment of choice. Due to the indiscriminate use of vancomycin, recently, we are seeing the emergence of vancomycin-intermediate sensitive S. aureus (VISA) and vancomycinresistant S. aureus (VRSA). The present study aims to evaluate the minimum inhibitory concentrations (MICs) of vancomycin and daptomycin among MRSA strains isolated from human clinical specimens Methods The study included 115 MRSA isolates collected over 26 months from July 2010 to September 2012. The strains were isolated from pus, urine, wound swabs, catheters, blood, and sputum. The bacteria were acquired from different inpatient and outpatient departments of Prathima Institute of Medical Sciences, Karimnagar, Telangana, India. Kirby-Bauer disk diffusion method using cefoxitin was used to confirm the MRSA isolates. The agar dilution and the Epsilometer method (E-test) were used to test the MICs of MRSA isolates against vancomycin and daptomycin, respectively, by the standard procedures recommended by the clinical laboratory standards institute (CLSI). Results Of the 115 S. aureus isolates, seven (6.08%) strains were resistant to vancomycin (VRSA) and 53 (46.08%) were found to be VISA using the new CLSI breakpoints. The MIC of the daptomycin was found to be ≤1 µg/ml for all the MRSA isolates. Conclusion The study results depicted an increasing trend in the vancomycin MICs among the MRSA isolates. Several tested strains show MICs in the intermediate sensitive range (VISA). The 1 2 3

Drug Delivery from PCL/Chitosan Multilayer Coatings for Metallic Implants

“…Van-loaded films also show no antibacterial activity, which may be due to a low diffusion of the drug in the agar medium or diffusion that lies below the vancomycin MIC reported for S. aureus , 2 μg/mL for the ATCC 25923 strain, 12 and from 4 to 8 μg/mL for VRSA. 36 Moreover, results of positive antibiotic control were in accordance with the expectable inhibition halos described in the literature as 18–23 37 and 17–21 38 for Dap and Van respectively, toward S. aureus ATCC 25923 assuring the assay suitability.…”

Phenotypic and Molecular Detection of Biofilm Formation in Methicillin-Resistant Staphylococcus Aureus Isolated From Different Clinical Source in Erbil City

“…23 A large number of MRSA strains are sensitive to penicillin, azithromycin, clindamycin, tetracycline, sulfamethoxazole, gentamicin, 24,25 In this study, the rate of resistance to erythromycin was 28.1%, which is not consistent with the study of J Szabó et al, and Romen Singh Naorem et al, which may be due to the different number of strains in the studies. 26,27 The insignificant resistance of MRSA strains to Vancomycin in this study is consistent with studies conducted by Vinay Kumar Moses et al and Chaudhari CN et al 22,28 The MSSA isolates were susceptible to most antibiotics tested. However, more resistance was observed to penicillin, azithromycin, clindamycin, and to some extent to clindamycin, tetracycline, tobramycin, Amikacin, gentamicin, ciprofloxacin, Norfloxacin, and levofloxacin.…”

“…Many of these illnesses can quickly become life-threatening if they are not properly controlled and treated. 22 The ability to form biofilm using some phenotypic and genotypic indicators is related to the spread of antibiotic resistance, especially resistance to methicillin in infected samples. It is one of the main concerns related to the ability of Staphylococcus aureus to threaten health.…”

Lignocellulosic membrane grafted with 4-vinylpiridine using radiation chemistry: antimicrobial activity of loaded vancomycin

“…Interestingly, the inhibition zone caused by vancomycin-loaded MS-g-4VP membrane was significantly greater (2.0 vs. 1.5 cm) than that observed for vancomycinloaded MS membrane, which can be related to the fact that MS-g-4VP membrane can load more vancomycin. Overall, these results highlight that the amounts loaded are sufficient to inhibit the growth of S. aureus (Moses et al 2020), a common pathogen present in chronic wounds.…”