Resistance Profiles and Biological Characteristics of Rifampicin-Resistant Staphylococcus aureus Small-Colony Variants

Zheng, Xiangkuo; Fang, Ru; Wang, Chong; Tian, Xuebin; Lin, Jie; Zeng, Weiliang; Zhou, Tieli; Xu, Chunyan

doi:10.2147/idr.s301863

Cited by 21 publications

(18 citation statements)

References 44 publications

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“…They are mainly acquired through nosocomial or urinary infections [ 56 , 57 ]. There are reports that several bacterial strains acquire multiple resistances to antibiotics [ 58 ], therefore, nanoparticles offer an alternative for their control [ 38 ]. However, we did not obtain antibacterial activity with the AuNPs in these same strains, unlike other authors [ 26 , 59 , 60 ].…”

Section: Discussionmentioning

confidence: 99%

Green Synthesis of Gold and Silver Nanoparticles Using Leaf Extract of Capsicum chinense Plant

et al. 2022

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So far, several studies have focused on the synthesis of metallic nanoparticles making use of extracts from the fruit of the plants from the genus Capsicum. However, as the fruit is the edible, and highly commercial, part of the plant, in this work we focused on the leaves, a part of the plant that is considered agro-industrial waste. The biological synthesis of gold (AuNPs) and silver (AgNPs) nanoparticles using aqueous extracts of root, stem and leaf of Capsicum chinense was evaluated, obtaining the best results with the leaf extract. Gold and silver nanoparticles synthesized using leaf extract (AuNPs-leaf and AgNPs-leaf, respectively) were characterized by UV-visible spectrophotometry (UV-Vis), Fourier Transform Infrared Spectroscopy with Attenuated Total Reflection (FTIR-ATR), X-ray Photoelectron Spectroscopy (XPS), Ultra Hight Resolution Scanning Electron Microscopy coupled to Energy-Dispersive X-ray spectroscopy (UHR-SEM-EDX) and Transmission Electron Microscopy (TEM), and tested for their antioxidant and antimicrobial activities. In addition, different metabolites involved in the synthesis of nanoparticles were analyzed. We found that by the use of extracts derived from the leaf, we could generate stable and easy to synthesize AuNPs and AgNPs. The AuNPs-leaf were synthesized using microwave radiation, while the AgNPs-leaf were synthesized using UV light radiation. The antioxidant activity of the extract, determined by ABTS, showed a decrease of 44.7% and 60.7% after the synthesis of the AuNPs-leaf and AgNPs-leaf, respectively. After the AgNPs-leaf synthesis, the concentration of polyphenols, reducing sugars and amino acids decreased by 15.4%, 38.7% and 46.8% in the leaf extract, respectively, while after the AuNPs-leaf synthesis only reducing sugars decreased by 67.7%. These results suggest that these groups of molecules are implicated in the reduction/stabilization of the nanoparticles. Although the contribution of these compounds in the synthesis of the AuNPs-leaf and the AgNPs-leaf was different. Finally, the AgNPs-leaf inhibited the growth of S. aureus, E. coli, S. marcescens and E. faecalis. All of them are bacterial strains of clinical importance due to their fast antibiotic resistance development.

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Section: Discussionmentioning

confidence: 99%

Green Synthesis of Gold and Silver Nanoparticles Using Leaf Extract of Capsicum chinense Plant

et al. 2022

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“…This highlights the possibility that in vitro activity of RFP may not adequately represent in vivo activity and certainly urges caution when using lower doses of the drug (≤6 mg/kg/day). Future prospective studies in dogs are needed to determine the prevalence and rapidity of RFP resistance upon initial drug exposure and the potential for biological and virulence changes in RPF‐resistant staphylococci 2 1 …”

Section: Discussionmentioning

confidence: 99%

Rifampicin treatment of canine multidrug‐resistant meticillin‐resistant staphylococcal pyoderma: A retrospective study of 51 cases

Harbour¹,

Schick²,

Mount³

et al. 2022

Veterinary Dermatology

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Background: Rifampicin (RFP) is a potential treatment for canine multidrugresistant (MDR) meticillin-resistant staphylococci (MRS), yet the use of lower doses based on recent MIC data has not been evaluated in vivo.Hypothesis/Objectives: To provide information on the efficacy and safety of low-dose range RFP (≤6 mg/kg/day) for the treatment of canine MDR MRS pyoderma.Animals: Fifty-one client-owned dogs. Materials and methods:Retrospective review of dogs medical records. Dogs were from 11 US dermatology referral practices and had oral RFP at ≤6 mg/kg/day. Data evaluated included response to treatment, adverse events, and serum changes in alanine aminotransferase (ALT) and alkaline phosphatase (ALP).Results: Complete resolution of pyoderma occurred in 39 of 51 dogs (76.5%).Topical antimicrobials were used concurrently in most cases (47 of 51; 92.2%). ALP elevation >1.5-fold of baseline or the high end of the reference range occurred in nine of 37 (24.3%) dogs, while ALT elevation above baseline and the high end of the reference range occurred in two of 36 (5.6%). Only six of 51 (11.8%) had clinical adverse events during treatment; five of six (83.3%) were mild reactions consisting of lethargy and gastrointestinal signs, while one dog had a possible cutaneous adverse drug reaction. Of those that experienced clinical adverse events, four of six (66.7%) did not have concurrent increased liver enzyme activity, while two of six (33.3%) had elevations in ALP alone. Conclusions and clinical relevance:Low-dose RFP (≤6 mg/kg/day) appears to be a relatively safe and effective single-agent systemic antibiotic in combination with topical antimicrobials for canine MDR MRS pyoderma.

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“…In line with previous description [ 18 ], the bacterial growth curve was analyzed. Briefly, MRSA N315 was maintained in nutrient agar and treated with luteolin at different concentrations (8, 16, 32, and 64 μ g/mL) for 24 hours, and the optical density (OD) values (at 600 nm) for isolated strains were detected using a microplate reader at every hour, after which the growth curves were analyzed.…”

Section: Methodsmentioning

confidence: 99%

Luteolin Inhibits the Biofilm Formation and Cytotoxicity of Methicillin-Resistant Staphylococcus aureus via Decreasing Bacterial Toxin Synthesis

Sun

Feng

et al. 2022

Evidence-Based Complementary and Alternative Medicine

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Owing to the fact that luteolin has antibacterial activity against Staphylococcus aureus (S. aureus) and methicillin-resistant S. aureus (MRSA), its specific mechanism in MRSA is worthy of investigation, which is the focus of this study. Initially, the collected S. aureus strains were treated with luteolin. Then, the minimum inhibitory concentration (MIC) of luteolin against the S. aureus strains was measured by the broth microdilution. The growth curves, biofilm formation, and cytotoxicity of treated S. aureus were detected using a microplate reader. The live and dead bacteria were evaluated using confocal laser scanning microscopy, the bacterial morphology was observed using scanning electron microscopy, and the S. aureus colony-forming unit (CFU) numbers were assessed. The levels of alpha hemolysin (α-hemolysin), delta hemolysin (δ-hemolysin), and hlaA were detected via western blot and RT-PCR. The mortality of mouse model with S. aureus systemic infection was analyzed, and the levels of IL-6, IL-8, IL-10, and TNF-α were quantitated using ELISA. Concretely, the MIC of luteolin against MRSA N315 was 64 μg/mL. Luteolin at 16 μg/mL did not affect the growth of MRSA N315, but inhibited the biofilm formation and CFU, and promoted the morphological changes and death of MRSA N315. Luteolin decreased the cytotoxicity and the levels of α-hemolysin, δ-hemolysin, and hlaA in MRSA N315, elevated MRSA-reduced mice survival rate, and differentially modulated the inflammatory cytokine levels in MRSA-infected mice. Collectively, luteolin inhibits biofilm formation and cytotoxicity of MRSA via blocking the bacterial toxin synthesis.

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Resistance Profiles and Biological Characteristics of Rifampicin-Resistant Staphylococcus aureus Small-Colony Variants

Cited by 21 publications

References 44 publications

Green Synthesis of Gold and Silver Nanoparticles Using Leaf Extract of Capsicum chinense Plant

Green Synthesis of Gold and Silver Nanoparticles Using Leaf Extract of Capsicum chinense Plant

Rifampicin treatment of canine multidrug‐resistant meticillin‐resistant staphylococcal pyoderma: A retrospective study of 51 cases

Luteolin Inhibits the Biofilm Formation and Cytotoxicity of Methicillin-Resistant Staphylococcus aureus via Decreasing Bacterial Toxin Synthesis

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