scholarly journals Prevalence of fosfomycin resistance and gene mutations in clinical isolates of methicillin-resistant Staphylococcus aureus

2020 ◽  
Author(s):  
Yi-Chien Lee ◽  
Pao-Yu Chen ◽  
Jann-Tay Wang ◽  
Shan-Chwen Chang
Keyword(s):  
Staphylococcus Aureus ◽  
Antimicrobial Agents ◽  
Genetic Relatedness ◽  
Protein A ◽  
Gene Mutations ◽  
Resistance Rate ◽  
Staphylococcal Protein A ◽  
Methicillin Resistant ◽  
Fosfomycin Resistance

Abstract Background: Fosfomycin exhibits excellent in vitro activity against multidrug-resistant pathogens, including methicillin-resistant Staphylococcus aureus (MRSA). Increasing fosfomycin resistance among clinical MRSA isolates was reported previously, but little is known about the genetic mechanisms of fosfomycin resistance.Methods: All MRSA isolates, collected in 2002 and 2012 by the Taiwan Surveillance of Antimicrobial Resistance (TSAR) program, were used in this study. Susceptibility to various antimicrobial agents, including fosfomycin, was determined by broth microdilution. Genetic determinants of fosfomycin resistance, including fosB carriage and murA, glpT and uhpT mutations, were investigated using PCR and sequencing of amplicons. Staphylococcal protein A (spa) typing was also performed to determine the genetic relatedness of MRSA isolates.Results: A total of 969 MRSA strains, 495 in the year 2002 and 474 in the year 2012, were analyzed. The overall in vitro susceptibility was 8.2% to erythromycin, 18.0% to clindamycin, 29.0% to tetracycline, 44.6% to ciprofloxacin, 57.5% to trimethoprim/sulfamethoxazole, 86.9% to rifampicin, 92.9% to fosfomycin and 100% to linezolid and vancomycin. A significant increase in the fosfomycin resistance rate was observed from 3.4% in 2002 to 11.0% in 2012. Of 68 fosfomycin-resistant MRSA isolates, 12 harbored the fosB gene, and expression of murA, uhpT, and glpT mutations was noted in 11, 59, and 66 isolates, respectively. Combination of mutations of uhpT and glpT genes (58 isolates) was the most prevalent resistant mechanism. The vast majority of the fosfomycin-resistant MRSA isolates belonged to spa type t002.Conclusions: An increased fosfomycin resistance rate of MRSA isolates was observed in our present study, mostly due to mutations in the glpT and uhpT genes. Clonal spread probably contributed to the increased fosfomycin resistance.

scholarly journals Prevalence of fosfomycin resistance and gene mutations in clinical isolates of methicillin-resistant Staphylococcus aureus

2020 ◽  
Author(s):  
Yi-Chien Lee ◽  
Pao-Yu Chen ◽  
Jann-Tay Wang ◽  
Shan-Chwen Chang
Keyword(s):  
Staphylococcus Aureus ◽  
Antimicrobial Agents ◽  
Genetic Relatedness ◽  
Protein A ◽  
Gene Mutations ◽  
Resistance Rate ◽  
Staphylococcal Protein A ◽  
Methicillin Resistant ◽  
Fosfomycin Resistance

Abstract Background: Fosfomycin exhibits excellent in vitro activity against multidrug-resistant pathogens, including methicillin-resistant Staphylococcus aureus (MRSA). Increasing fosfomycin resistance among clinical MRSA isolates was reported previously, but little is known about the relative abundance of Fosfomycin resistance genes in MRSA isolates circulating in Taiwan.Methods: All MRSA isolates, collected in 2002 and 2012 by the Taiwan Surveillance of Antimicrobial Resistance (TSAR) program, were used in this study. Susceptibility to various antimicrobial agents, including fosfomycin, was determined by broth microdilution. Genetic determinants of fosfomycin resistance, including fosB carriage and murA, glpT and uhpT mutations, were investigated using PCR and sequencing of amplicons. Staphylococcal protein A (spa) typing was also performed to determine the genetic relatedness of MRSA isolates.Results: A total of 969 MRSA strains, 495 in the year 2002 and 474 in the year 2012, were analyzed. The overall in vitro susceptibility was 8.2% to erythromycin, 18.0% to clindamycin, 29.0% to tetracycline, 44.6% to ciprofloxacin, 57.5% to trimethoprim/sulfamethoxazole, 86.9% to rifampicin, 92.9% to fosfomycin and 100% to linezolid and vancomycin. A significant increase in the fosfomycin resistance rate was observed from 3.4% in 2002 to 11.0% in 2012. Of 68 fosfomycin-resistant MRSA isolates, several genetic backgrounds probably contributing to fosfomycin resistance were identified. Twelve isolates harbored the fosB gene, and various mutations in murA, uhpT, and glpT genes were noted in 11, 59, and 66 isolates, respectively. The most prevalent gene mutations were found in the combination of uhpT and glpT genes (58 isolates). The vast majority of the fosfomycin-resistant MRSA isolates belonged to spa type t002.Conclusions: An increased fosfomycin resistance rate of MRSA isolates was observed in our present study, mostly due to mutations in the glpT and uhpT genes. Clonal spread probably contributed to the increased fosfomycin resistance.

scholarly journals Efficacy of Azithromycin in a Mouse Pneumonia Model against Hospital-Acquired Methicillin-Resistant Staphylococcus aureus

2019 ◽  
Vol 63 (9) ◽  
Author(s):  
Yu Yamashita ◽  
Kentaro Nagaoka ◽  
Hiroki Kimura ◽  
Masaru Suzuki ◽  
Satoshi Konno ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Protein A ◽  
Lavage Fluid ◽  
Suppressive Effect ◽  
The Other ◽  
Staphylococcal Protein A ◽  
Methicillin Resistant ◽  
Content Type

ABSTRACT The use of macrolides against pneumonia has been reported to improve survival; however, little is known about their efficacy against methicillin-resistant Staphylococcus aureus (MRSA) pneumonia. In this study, we investigated the effect of azithromycin (AZM) and compared it with that of vancomycin (VCM) and daptomycin (DAP) in a murine model of MRSA pneumonia. Mice were infected with MRSA by intratracheal injection and then treated with AZM, VCM, or DAP. The therapeutic effect of AZM, in combination or not with the other drugs, was compared in vivo, whereas the effect of AZM on MRSA growth and toxin mRNA expression was evaluated in vitro. In vivo, the AZM-treated group showed significantly longer survival and fewer bacteria in the lungs 24 h after infection than the untreated group, as well as the other anti-MRSA drug groups. No significant decrease in cytokine levels (interleukin-6 [IL-6] and macrophage inflammatory protein-2 [MIP-2]) in bronchoalveolar lavage fluid or toxin expression levels (α-hemolysin [Hla] and staphylococcal protein A [Spa]) was observed following AZM treatment. In vitro, AZM suppressed the growth of MRSA in late log phase but not in stationary phase. No suppressive effect against toxin production was observed following AZM treatment in vitro. In conclusion, contrary to the situation in vitro, AZM was effective against MRSA growth in vivo in our pneumonia model, substantially improving survival. The suppressive effect on MRSA growth at the initial stage of pneumonia could underlie the potential mechanism of AZM action against MRSA pneumonia.

Multilocus Sequence Typing and Staphylococcal Protein A Typing Revealed Novel and Diverse Clones of Methicillin-Resistant Staphylococcus aureus in Seafood and the Aquatic Environment

2017 ◽  
Vol 80 (3) ◽  
pp. 476-481 ◽  
Author(s):  
V. Murugadas ◽  
C. Joseph Toms ◽  
Sara A. Reethu ◽  
K. V. Lalitha
Keyword(s):  
Staphylococcus Aureus ◽  
Aquatic Environment ◽  
Multilocus Sequence Typing ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
Protein A ◽  
Staphylococcal Protein A ◽  
Spa Typing ◽  
Methicillin Resistant ◽  
Staphylococcal Protein ◽  
Mrsa Strains

ABSTRACT Methicillin-resistant Staphylococcus aureus (MRSA) has been a global health concern since the 1960s, and isolation of this pathogen from food-producing animals has been increasing. However, little information is available on the prevalence of MRSA and its clonal characteristics in seafood and the aquatic environment. In this study, 267 seafood and aquatic environment samples were collected from three districts of Kerala, India. Staphylococcal protein A (spa) typing and multilocus sequence typing (MLST) was performed for 65 MRSA strains isolated from 20 seafood and aquatic environment samples. The MRSA clonal profiles were t657-ST772, t002-ST5, t334-ST5, t311-ST5, t121-ST8, t186-ST88, t127-ST1, and two non-spa assignable strains. Whole spa gene sequence analysis along with MLST confirmed one strain as t711-ST6 and another as a novel MRSA clone identified for the first time in seafood and the aquatic environment with a t15669 spa type and a new MLST profile of ST420-256-236-66-82-411-477. The MRSA strains were clustered into five clonal complexes based on the goeBURST algorithm, indicating high diversity among MRSA strains in seafood and the aquatic environment. The novel clone formed a separate clonal complex with matches to three loci. This study recommends large-scale spa typing and MLST of MRSA isolates from seafood and the aquatic environment to determine the prevalence of new MRSA clones. This monitoring process can be useful for tracing local spread of MRSA isolates into the seafood production chain in a defined geographical area.

scholarly journals The Synergistic Effect of Nicotine and Staphylococcus aureus on Peri-Implant Infections

2021 ◽  
Vol 9 ◽  
Author(s):  
Yao Hu ◽  
Wen Zhou ◽  
Chengguang Zhu ◽  
Yujie Zhou ◽  
Qiang Guo ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Synergistic Effects ◽  
Protein A ◽  
Treated Group ◽  
Combination Group ◽  
Staphylococcal Protein A ◽  
Receptor Activator ◽  
And Staphylococcus Aureus

Smoking is considered a key risk factor for implant survival; however, how it interacts with the pathogens in peri-implant infections is not clear. Here, we identified that nicotine, the key component of cigarette smoking, can interact with Staphylococcus aureus and synergistically induce peri-implant infections in a rat osteolysis model. The nicotine–S. aureus combination group increased the gross bone pathology, osteolysis, periosteal reactions, and bone resorption compared to the nicotine or S. aureus single treated group (p < 0.05). Nicotine did not promote the proliferation of S. aureus both in vitro and in vivo, but it can significantly upregulate the expression of staphylococcal protein A (SpA), a key virulence factor of S. aureus. The nicotine–S. aureus combination also synergistically activated the expression of RANKL (receptor activator of nuclear factor-kappa B ligand, p < 0.05) to promote the development of peri-implant infections. The synergistic effects between nicotine and S. aureus infection can be a new target to reduce the peri-implant infections.

scholarly journals In vitro activities of oxazolidinone compounds U100592 and U100766 against Staphylococcus aureus and Staphylococcus epidermidis.

1996 ◽  
Vol 40 (3) ◽  
pp. 799-801 ◽  
Author(s):  
G W Kaatz ◽  
S M Seo
Keyword(s):  
Staphylococcus Aureus ◽  
Staphylococcus Epidermidis ◽  
Inhibitory Activity ◽  
Antimicrobial Agents ◽  
Methicillin Resistant ◽  
Clinical Strains ◽  
Time Kill

The new oxazolidinone antimicrobial agents U100592 and U100766 demonstrated good in vitro inhibitory activity against clinical strains of Staphylococcus aureus and Staphylococcus epidermidis regardless of methicillin susceptibility. Both agents appeared bacteriostatic by time-kill analysis. Stable resistance to low multiples of the MIC of either drug could be produced only in methicillin-resistant S. aureus.

scholarly journals Introduction of the mec Element (Methicillin Resistance) into Staphylococcus aureus Alters In Vitro Functional Activities of Fibrinogen and Fibronectin Adhesins

1998 ◽  
Vol 42 (3) ◽  
pp. 564-570 ◽  
Author(s):  
Pierre E. Vaudaux ◽  
Vincenza Monzillo ◽  
Patrice Francois ◽  
Daniel P. Lew ◽  
Tim J. Foster ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Methicillin Resistance ◽  
Bacterial Colonization ◽  
Protein A ◽  
Methicillin Resistant ◽  
Functional Activities ◽  
Extracellular Matrix Components ◽  
Resistant Strains ◽  
The Impact

ABSTRACT Some methicillin-resistant strains of Staphylococcus aureus are defective in the production of major surface components such as protein A, clumping factor, or other important adhesins to extracellular matrix components which may play a role in bacterial colonization and infection. To evaluate the impact of methicillin resistance (mec) determinants on bacterial adhesion mediated by fibrinogen or fibronectin adhesins, we compared the in vitro attachment of two genetically distinct susceptible strains (NCTC8325 and Newman) to protein-coated surfaces with that of isogenic methicillin-resistant derivatives. All strains containing an intactmec element in their chromosomes were found to be defective in adhesion to fibrinogen and fibronectin immobilized on polymethylmethacrylate coverslips, regardless of the presence or absence of additional mutations in the femA,femB, or femC gene, known to decrease expression of methicillin resistance in S. aureus. Western ligand affinity blotting or immunoblotting of cell wall-associated adhesins revealed similar contents of fibrinogen- or fibronectin-binding proteins in methicillin-resistant strains compared to those of their methicillin-susceptible counterparts. In contrast to methicillin-resistant strains carrying a mec element in their genomes, methicillin-resistant strains constructed in vitro, by introducing the mecA gene on a plasmid, retained their adhesion phenotypes. In conclusion, the chromosomal insertion of themec element into genetically defined strains of S. aureus impairs the in vitro functional activities of fibrinogen or fibronectin adhesins without altering their production. This effect is unrelated to the activity of the mecA gene.

scholarly journals Clonality, virulence genes, and antibiotic resistance of Staphylococcus aureus isolated from blood in Shandong, China

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Xuezhi Wang ◽  
Dongzi Lin ◽  
Zengqi Huang ◽  
Jinmei Zhang ◽  
Wenyan Xie ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Antibiotic Resistance ◽  
Infection Control ◽  
Virulence Genes ◽  
Genetic Relatedness ◽  
Protein A ◽  
Epidemiological Data ◽  
Control Measures ◽  
Staphylococcal Protein A ◽  
Infection Control Measures

Abstract Background Bloodstream infection (BSI) caused by Staphylococcus aureus (S. aureus) can be life-threatening and pose a great challenge to infection control and clinical treatment. However, little information exists regarding the characterization of S. aureus in BSI patients in Shandong, China. To identify the clonality, virulence genes, and antibiotic resistance of S. aureus in blood, a total of 101 nonrepetitive blood isolates were collected. The antibiotic resistance phenotypes were determined, and virulence genes were analyzed with polymerase chain reaction (PCR). Finally, the genetic relatedness was investigated with Staphylococcus chromosomal cassette mec (SCCmec) typing for methicillin-resistant S. aureus (MRSA) isolates, Staphylococcal protein A (spa), and multilocus sequence typing (MLST) for all of 101 isolates. Results Of the 101 S. aureus isolates, 24 MRSA isolates and 77 methicillin-susceptible S. aureus (MSSA) isolates were identified. Overall, MRSA isolates had higher resistance rates than MSSA isolates when exposed to any of the 15 antibiotics tested in this study except for trimethoprim/sulfamethoxazole. Among the 17 virulence genes tested in this study, hla, hld, and hlg could be detected in all isolates. MRSA isolates were more likely to carry seb and hlb genes, while MSSA isolates were more likely to carry seg and sei genes. Thirty-five sequence types (STs) and 49 spa types were identified, of which ST59-t437 and ST398-t571 were the most abundant. These two genotypes were also the most abundant ST-spa types in MRSA and MSSA isolates, but their abundances shifted over time, with ST398-t571 being the predominant genotype from 2016 to 2017, and ST59-t437 from 2018 to 2020. Besides, all the ST59-t437 isolates harbored hlgb gene, whereas most (88.9%) ST398-t571 did not. In addition, twenty-four MRSA isolates were subject to SCCmec typing. SCCmec IVa was the most prevalent SCCmec type, and all the ST59-t437 MRSA isolates were SCCmec IVa. We also observed 15 new STs, and some of them were MRSA. Conclusion These findings provide additional observations and epidemiological data for blood S. aureus isolates, which can improve future infection-control measures and aid in potential clinical treatments in hospitals and other clinical settings.

scholarly journals 611. Fosfomycin Resistance of Multidrug-Resistant Escherichia coli and Mechanisms of Fosfomycin Resistance

2019 ◽  
Vol 6 (Supplement_2) ◽  
pp. S285-S285
Author(s):  
Hyeri Seok ◽  
Ji Hoon Jeon ◽  
Hee Kyoung Choi ◽  
Won Suk Choi ◽  
Dae Won Park ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Antimicrobial Agents ◽  
Multidrug Resistant ◽  
Resistance Rate ◽  
Coli Strain ◽  
Resistant Bacteria ◽  
E Coli ◽  
Broth Microdilution Method ◽  
Fosfomycin Resistance

Abstract Background Fosfomycin is one of the antibiotics that may be a candidate for the next-generation antimicrobial agents againt multidrug-resistant bacteria. To date, it is known that the resistance rate is not high for Escherichia coli. However, it is necessary to update the fosfomycin resistance rates in E. coli according to the studies that extended spectrum β-lactamase (ESBL) producing E. coli strains are highly resistance to fosfomycin. We evaluated the resistance rate of fosfomycin, the resistant mechanism of fosfomycin in E. coli, and the activity of fosfomycin against susceptible and resistant strains of E. coli. Methods A total of 283 clinical isolates was collected from patients with Escherichia coli species during the period of January 2018 to June 2018, in three tertiary hospitals of Republic of Korea. In vitro antimicrobial susceptibility tests were performed in all E. coli isolates using the broth microdilution method according to the Clinical and Laboratory Standard Institute (CLSI). Multilocus sequence typing (MLST) of the Oxford scheme was conducted to determine the genotypes of E. coli isolated. Fosfomycin genes were investigated for all fosfomycin-resistant E. coli strains. Results The overall resistance rate to fosfomycin was 10.2%, compared with 53.4%, 46.3%, 41.3%, 31.1%, 10.6%, 2.5%, and 2.1% for ciprofloxacin, cefixime, cefepime, piperacillin/tazobactam, colistin, ertapenem, and amikacin, respectively. The 29 fosfomycin-resistant isolates did not show a clonal pattern on the phylogenetic tree. MurA and glp genes were identified in all strains. FosA3 were identified in two strains and uhp gene were identified in 4 strains. In time-kill curve studies, fosfomycin was more bactericidal than cefixime against all sensitive E. coli strain. Morever, fosfomycin was more bactericidal than piperacillin/tazobactam against ESBL-producing E. coli strain. Conclusion The resistant rate of fosfomycin to E. coli is still low. Fosfomycin was active against E. coli including ESBL producing strains. Disclosures All authors: No reported disclosures.

scholarly journals Antimicrobial and Antibiofilm Activities of Essential Oils against Escherichia coli O157:H7 and Methicillin-Resistant Staphylococcus aureus (MRSA)

Antibiotics ◽  
2020 ◽  
Vol 9 (11) ◽  
pp. 730
Author(s):  
Nicolás Gómez-Sequeda ◽  
Marlon Cáceres ◽  
Elena E. Stashenko ◽  
William Hidalgo ◽  
Claudia Ortiz
Keyword(s):  
Staphylococcus Aureus ◽  
Essential Oils ◽  
Antimicrobial Agents ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
Biological Activities ◽  
Antibiofilm Activity ◽  
Methicillin Resistant ◽  
E Coli ◽  
Microbial Infections

The emergence of multidrug resistant microorganisms represents a global challenge due to the lack of new effective antimicrobial agents. In this sense, essential oils (EOs) are an alternative to be considered because of their anti-inflammatory, antiviral, antibacterial, and antibiofilm biological activities. Therefore, multiple efforts have been made to consider the potential use of EOs in the treatment of infections which are caused by resistant microorganisms. In this study, 15 EOs of both Colombian and introduced aromatic plants were evaluated against pathogenic strains of E. coli O157:H7 and methicillin resistant Staphylococcus aureus (MRSA) in planktonic and sessile states in order to identify relevant and promising alternatives for the treatment of microbial infections. Forty different compounds were identified in the 15 EO with nine of them constituted mainly by oxygenated monoterpenes (OM). EOs from Lippia origanoides, chemotypes thymol, and carvacrol, displayed the highest antibacterial activity against E. coli O157:H7 (MIC50 = 0.9 and 0.3 mg/mL, respectively) and MRSA (MIC50 = 1.2 and 0.6 mg/mL, respectively). These compounds from EOs had also the highest antibiofilm activity (inhibition percentage > 70.3%). Using scanning electron microscopy (SEM), changes in the size and morphology of both bacteria were observed when they were exposed to sub-inhibitory concentrations of L. origanoides EO carvacrol chemotype. EOs from L. origanoides, thymol, and carvacrol chemotypes represented a viable alternative for the treatment of microbial infections; however, the Selectivity Index (SI ≤ 3) indicated that it was necessary to study alternatives to reduce its in vitro cytotoxicity.

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