Abstract:Enterococcus faecalis, Enterococcus faecium and Staphylococcus aureus are both common commensals and major opportunistic human pathogens. In recent decades, these bacteria have acquired broad resistance to several major classes of antibiotics, including commonly employed glycopeptides. Exemplified by resistance to vancomycin, glycopeptide resistance is mediated through intrinsic gene mutations, and/or transferrable van resistance gene cassette-carrying mobile genetic elements. Here, this review will discuss th… Show more
“…And in 2002, the first vancomycin resistant Staphylococcus aureus (VRSA) strain was isolated in the United States. 10 The prevalence of VRSA increased from 2% before 2006 to 7% in 2015–2020 ( Figure 1 ). 11 Figure 1 Evolution of drug resistance in S. aureus .…”
Staphylococcus aureus
is a common human pathogen with a variety of virulence factors, which can cause multiple infectious diseases. In recent decades, due to the constant evolution and the abuse of antibiotics,
Staphylococcus aureus
was becoming more resistant, the infection rate of MRSA remained high, and clinical treatment of MRSA became more difficult. The genetic diversity of MRSA was mainly represented by the continuous emergence of epidemic strains, resulting in the constant changes of epidemic clones. Different classes of MRSA resulted in different epidemics and resistance characteristics, which could affect the clinical symptoms and treatments. MRSA had also spread from traditional hospitals to community and livestock environments, and the new clones established a relationship between animals and humans, promoting further evolution of MRSA. Since the resistance mechanism of MRSA is very complex, it is important to clarify these resistance mechanisms at the molecular level for the treatment of infectious diseases. We firstly described the diversity of SCC
mec
elements, and discussed the types of SCC
mec
, its drug resistance mechanisms and expression regulations. Then, we described how the
vanA
operon makes
Staphylococcus aureus
resistant to vancomycin and its expression regulation. Finally, a brief introduction was given to the drug resistance mechanisms of biofilms and efflux pump systems. Analyzing the resistance mechanism of MRSA can help study new anti-infective drugs and alleviate the evolution of MRSA. At the end of the review, we summarized the treatment strategies for MRSA infection, including antibiotics, anti-biofilm agents and efflux pump inhibitors. To sum up, here we reviewed the epidemic characteristics of
Staphylococcus aureus
, summarized its classifications, drug resistance mechanisms of MRSA (SCC
mec
element,
vanA
operon, biofilm and active efflux pump system) and novel therapy strategies, so as to provide a theoretical basis for the treatment of MRSA infection.
“…And in 2002, the first vancomycin resistant Staphylococcus aureus (VRSA) strain was isolated in the United States. 10 The prevalence of VRSA increased from 2% before 2006 to 7% in 2015–2020 ( Figure 1 ). 11 Figure 1 Evolution of drug resistance in S. aureus .…”
Staphylococcus aureus
is a common human pathogen with a variety of virulence factors, which can cause multiple infectious diseases. In recent decades, due to the constant evolution and the abuse of antibiotics,
Staphylococcus aureus
was becoming more resistant, the infection rate of MRSA remained high, and clinical treatment of MRSA became more difficult. The genetic diversity of MRSA was mainly represented by the continuous emergence of epidemic strains, resulting in the constant changes of epidemic clones. Different classes of MRSA resulted in different epidemics and resistance characteristics, which could affect the clinical symptoms and treatments. MRSA had also spread from traditional hospitals to community and livestock environments, and the new clones established a relationship between animals and humans, promoting further evolution of MRSA. Since the resistance mechanism of MRSA is very complex, it is important to clarify these resistance mechanisms at the molecular level for the treatment of infectious diseases. We firstly described the diversity of SCC
mec
elements, and discussed the types of SCC
mec
, its drug resistance mechanisms and expression regulations. Then, we described how the
vanA
operon makes
Staphylococcus aureus
resistant to vancomycin and its expression regulation. Finally, a brief introduction was given to the drug resistance mechanisms of biofilms and efflux pump systems. Analyzing the resistance mechanism of MRSA can help study new anti-infective drugs and alleviate the evolution of MRSA. At the end of the review, we summarized the treatment strategies for MRSA infection, including antibiotics, anti-biofilm agents and efflux pump inhibitors. To sum up, here we reviewed the epidemic characteristics of
Staphylococcus aureus
, summarized its classifications, drug resistance mechanisms of MRSA (SCC
mec
element,
vanA
operon, biofilm and active efflux pump system) and novel therapy strategies, so as to provide a theoretical basis for the treatment of MRSA infection.
“…It developed in humans due to avoparcin use in livestock where it passed the resistant bacteria from animals to humans 6 . The half way vancomycin resistance strains turned into completely vancomycin-resistance staphylococcus aureus reported in 1997 therefore banned by European Union in animal feed 7 .…”
Misuse of antibiotics leads to the worldwide spread of antibiotic resistance, which motivates scientists to create new antibiotics. The recurring UTI due to antibiotics-resistant microorganism’s challenges scientists globally. The biogenic nanoparticles have the potential to meet the escalating requirements of novel antimicrobial agents. The green synthesis of nanoparticles (NPs) gained more attention due to their reliable applications against resistant microbes. The current study evaluates the biogenic ZnO NPs of Mentha piperata extract against resistant pathogens of urinary tract infections by agar well diffusion assay. The biogenic ZnO NPs revealed comparatively maximum inhibition in comparison to synthetic antibiotics against two bacterial strains (Proteus mirabilis, Pseudomonas aeruginosa) and a fungal strain (Candida albicans).The synthesized biogenic ZnO NPs alone revealed maximum activities than the combination of plant extract (PE) and ZnO NPs, and PE alone. The physiochemical features of ZnO NPs characterized through UV–Vis spectroscopy, FTIR, XRD, SEM, and EDX. The UV–Vis spectroscopy revealed 281.85 nm wavelengths; the XRD pattern revealed the crystalline structure of ZnO NPs. The FTIR analysis revealed the presence of carboxylic and nitro groups, which could be attributed to plant extract. SEM analysis revealed spherical hollow symmetry due to electrostatic forces. The analysis via EDX confirmed the presence of Zn and oxygen in the sample. The physiochemical features of synthesized ZnO NPs provide pivotal information such as quality and effectiveness. The current study revealed excellent dose-dependent antimicrobial activity against the pathogenic isolates from UTI-resistant patients. The higher concentration of ZnONPs interacts with the cell membrane which triggers oxidative burst. They may bind with the enzymes and proteins and brings epigenetic alteration which leads to membrane disruption or cell death.
“…But even to these compounds, enterococci have developed resistance mechanisms encoded on mobile genetic elements or plasmids ( 27 , 28 ). So far, this type of vancomycin resistance encoded by the vanA or vanB genes has predominantly been demonstrated in Enterococcus faecium but may also be present in Enterococcus faecalis ( 29 – 33 ).…”
IntroductionEnterococci are usually low pathogenic, but can cause invasive disease under certain circumstances, including urinary tract infections, bacteremia, endocarditis, and meningitis, and are associated with peritonitis and intra-abdominal abscesses. Increasing resistance of enterococci to glycopeptides and fluoroquinolones, and high-level resistance to aminoglycosides is a concern. National antimicrobial resistance (AMR) surveillance data for enterococci from the Middle East and North Africa (MENA) and the Gulf region is scarce.MethodsA retrospective 12-year analysis of N = 37,909 non-duplicate diagnostic Enterococcus spp. isolates from the United Arab Emirates (UAE) was conducted. Data was generated by routine patient care during 2010–2021, collected by trained personnel and reported by participating surveillance sites to the UAE National AMR Surveillance program. Data analysis was conducted with WHONET.ResultsEnterococcus faecalis was the most commonly reported species (81.5%), followed by Enterococcus faecium (8.5%), and other enterococci species (4.8%). Phenotypically vancomycin-resistant enterococci (VRE) were found in 1.8% of Enterococcus spp. isolates. Prevalence of VRE (%VRE) was highest for E. faecium (8.1%), followed by E. faecalis (0.9%). A significant level of resistance to glycopeptides (%VRE) for these two species has been observed in the majority of observed years [E. faecalis (0–2.2%), 2010: 0%, 2021: 0.6%] and E. faecium (0–14.2%, 2010: 0%, 2021: 5.8%). Resistance to fluoroquinolones was between 17 and 29% (E. faecalis) and was higher for E. faecium (between 42 and 83%). VRE were associated with higher patient mortality (RR: 2.97), admission to intensive care units (RR: 2.25), and increased length of stay (six excess inpatient days per VRE case), as compared to vancomycin-susceptible Enterococcus spp.DiscussionPublished data on Enterococcus infections, in particular VRE-infections, in the UAE and MENA region is scarce. Our data demonstrates that VRE-enterococci are relatively rare in the UAE, however showing an increasing resistance trend for several clinically important antibiotic classes, causing a concern for the treatment of serious infections caused by enterococci. This study also demonstrates that VRE were associated with higher mortality, increased intensive care unit admission rates, and longer hospitalization, thus poorer clinical outcome and higher associated costs in the UAE. We recommend the expansion of current surveillance techniques (e.g., local VRE screening), stricter infection prevention and control strategies, and better stewardship interventions. Further studies on the molecular epidemiology of enterococci are needed.
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