scholarly journals ReducedIn VitroActivity of Ceftaroline by Etest among Clonal Complex 239 Methicillin-Resistant Staphylococcus aureus Clinical Strains from Australia

2015 ◽  
Vol 59 (12) ◽  
pp. 7837-7841 ◽  
Author(s):  
I. J. Abbott ◽  
A. W. J. Jenney ◽  
C. J. Jeremiah ◽  
M. Mirčeta ◽  
J. P. Kandiah ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
Clonal Complex ◽  
Multidrug Resistant ◽  
Clinical Isolates ◽  
Methicillin Resistant ◽  
Content Type ◽  
Clinical Strains ◽  
Resistant Phenotype

ABSTRACTA total of 421 methicillin-resistantStaphylococcus aureus(MRSA) clinical isolates were tested for ceftaroline susceptibility by Etest (bioMérieux). A multidrug resistant phenotype was found in 40.9%, and clonal complex 239 (CC239) was found in 33.5%. Ceftaroline nonsusceptibility (MIC, >1.0 μg/ml) was 16.9% overall. Nonsusceptibility was significantly higher in CC239 (41.1%, 58/141) and in isolates with a multidrug resistant phenotype (35.5%, 61/172) compared with comparators (P< 0.0001). Nonsusceptibility of common multidrug resistant MRSA clones limits the empirical use of ceftaroline for these infections.

scholarly journals Ceftaroline-Resistant, Daptomycin-Tolerant, and Heterogeneous Vancomycin-Intermediate Methicillin-Resistant Staphylococcus aureus Causing Infective Endocarditis

2017 ◽  
Vol 61 (3) ◽  
Author(s):  
Masayuki Nigo ◽  
Lorena Diaz ◽  
Lina P. Carvajal ◽  
Truc T. Tran ◽  
Rafael Rios ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Infective Endocarditis ◽  
Active Site ◽  
Drug Exposure ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
Multidrug Resistant ◽  
Present Evidence ◽  
Methicillin Resistant ◽  
Content Type ◽  
Resistant Phenotype

ABSTRACT We report a case of infective endocarditis (IE) caused by ceftaroline-resistant, daptomycin-tolerant, and heterogeneous vancomycin-intermediate methicillin-resistant S. aureus (MRSA). Resistance to ceftaroline emerged in the absence of drug exposure, and the E447K substitution in the active site of PBP2a previously associated with ceftaroline resistance was identified. Additionally, we present evidence of patient-to-patient transmission of the strain within the same unit. This case illustrates the difficulties in treating MRSA IE in the setting of a multidrug-resistant phenotype.

scholarly journals Scope and Predictive Genetic/Phenotypic Signatures of Bicarbonate (NaHCO3) Responsiveness and β-Lactam Sensitization in Methicillin-Resistant Staphylococcus aureus

2020 ◽  
Vol 64 (5) ◽  
Author(s):  
Selvi C. Ersoy ◽  
Mariam Otmishi ◽  
Vanessa T. Milan ◽  
Liang Li ◽  
Youngju Pak ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
Clonal Complex ◽  
Population Analysis ◽  
Methicillin Resistant ◽  
Content Type ◽  
Mueller Hinton ◽  
Testing Medium ◽  
Mrsa Strains ◽  
Mueller Hinton Broth

ABSTRACT Addition of sodium bicarbonate (NaHCO3) to standard antimicrobial susceptibility testing medium reveals certain methicillin-resistant Staphylococcus aureus (MRSA) strains to be highly susceptible to β-lactams. We investigated the prevalence of this phenotype (NaHCO3 responsiveness) to two β-lactams among 58 clinical MRSA bloodstream isolates. Of note, ∼75% and ∼36% of isolates displayed the NaHCO3 responsiveness phenotype to cefazolin (CFZ) and oxacillin (OXA), respectively. Neither intrinsic β-lactam MICs in standard Mueller-Hinton broth (MHB) nor population analysis profiles were predictive of this phenotype. Several genotypic markers (clonal complex 8 [CC8]; agr I and spa t008) were associated with NaHCO3 responsiveness for OXA.

scholarly journals Novel Types of Staphylococcal Cassette ChromosomemecElements Identified in Clonal Complex 398 Methicillin-Resistant Staphylococcus aureus Strains

2011 ◽  
Vol 55 (6) ◽  
pp. 3046-3050 ◽  
Author(s):  
Shanshuang Li ◽  
Robert Leo Skov ◽  
Xiao Han ◽  
Anders Rhod Larsen ◽  
Jesper Larsen ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
Clonal Complex ◽  
Subtype C ◽  
Methicillin Resistant ◽  
Content Type ◽  
Original Host ◽  
Mrsa Strains ◽  
Type V ◽  
Staphylococcal Cassette Chromosome

ABSTRACTThe structures of staphylococcal cassette chromosomemec(SCCmec) elements carried by 31 clonal complex 398 (CC398) methicillin-resistantStaphylococcus aureus(MRSA) strains isolated from the participants at a conference were analyzed. The SCCmecs were classified into novel types, namely, IX, X, V(5C2&5) subtype c, and IVa. Type V(5C2&5) subtype c, IX, and X SCCmecs carried genes conferring resistance to metals. The structures of SCCmecs from CC398 strains were distinct from those normally found in humans, adding to the evidence that humans are not the original host for CC398.

scholarly journals TelavancinIn VitroActivity against a Collection of Methicillin-Resistant Staphylococcus aureus Isolates, Including Resistant Subsets, from the United States

2015 ◽  
Vol 59 (3) ◽  
pp. 1811-1814 ◽  
Author(s):  
Rodrigo E. Mendes ◽  
Helio S. Sader ◽  
Robert K. Flamm ◽  
David J. Farrell ◽  
Ronald N. Jones
Keyword(s):  
United States ◽  
Staphylococcus Aureus ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
The United States ◽  
Multidrug Resistant ◽  
Methicillin Resistant ◽  
Content Type

ABSTRACTTelavancin had MIC50, MIC90, and MIC100values of 0.03, 0.06, and 0.12 μg/ml, respectively, against methicillin-susceptibleStaphylococcus aureus, methicillin-resistantS. aureus(MRSA), and non-multidrug-resistant (non-MDR) and MDR subsets. MRSA with elevated MIC values for vancomycin (2 to 4 μg/ml) or daptomycin (1 to 2 μg/ml) had telavancin MIC50(0.06 μg/ml) values 2-fold higher than those of isolates with lower MIC results (MIC50, 0.03 μg/ml). However, telavancin had MIC90and MIC100results of 0.06 and 0.12 μg/ml (100% susceptible), respectively, regardless of the MRSA subset.

scholarly journals Complete Genome Sequence of Community-Acquired Methicillin-Resistant Staphylococcus aureus Strain RJ1267, Isolated in Shanghai, China

2020 ◽  
Vol 9 (18) ◽  
Author(s):  
Xianchun Zong ◽  
Dehua Liu ◽  
Min Li ◽  
Baolin Sun
Keyword(s):  
Staphylococcus Aureus ◽  
Genome Sequence ◽  
Complete Genome Sequence ◽  
Complete Genome ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
Multidrug Resistant ◽  
Sequence Type ◽  
Aureus Strain ◽  
Methicillin Resistant ◽  
Content Type

Staphylococcal pathogens, especially multidrug-resistant Staphylococcus aureus, are responsible for various clinical infections. Multilocus sequence type 630 (ST630) methicillin-resistant Staphylococcus aureus has been shown to have augmented pathogenicity in humans. In this announcement, we report the complete genome sequence of community-acquired methicillin-resistant strain RJ1267 of Staphylococcus aureus ST630.

scholarly journals A Clonal Complex 12 Methicillin-Resistant Staphylococcus aureus Strain, West Australian MRSA-59, Harbors a Novel Pseudo-SCCmecElement

2015 ◽  
Vol 59 (11) ◽  
pp. 7142-7144 ◽  
Author(s):  
Stefan Monecke ◽  
Geoffrey W. Coombs ◽  
Julie Pearson ◽  
Helmut Hotzel ◽  
Peter Slickers ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
Clonal Complex ◽  
Copper Resistance ◽  
Aureus Strain ◽  
Coagulase Negative Staphylococci ◽  
Methicillin Resistant ◽  
Content Type ◽  
Reading Frame ◽  
Link Type

ABSTRACTA West Australian methicillin-resistantStaphylococcus aureusstrain (WA MRSA-59) was characterized by microarray and sequencing. Its pseudo-staphylococcal cassette chromosomemec(SCCmec) element compriseddcs,Q9XB68-dcs,mvaS-SCC,Q5HJW6,dru,ugpQ,ydeM,mecA-mecR-mecI, txbimecI,tnpIS431,copA2-mco(copper resistance),ydhK,arsC-arsB-arsR(arsenic resistance), open reading frame PT43, andper-2. Recombinase genes,xylR(mecR2), and PSM-mec(phenol-soluble modulin) were absent. We suggest thatmeccomplex A should be split into two subtypes. One harbors PSM-mecandxylR(mecR2). It is found in SCCmectypes II, III, and VIII. The second subtype, described herein, is present in WA MRSA-59 and some coagulase-negative staphylococci.

scholarly journals Complete Genome Sequences of Canadian Epidemic Methicillin-Resistant Staphylococcus aureus Strains CMRSA3 and CMRSA6

2018 ◽  
Vol 7 (5) ◽  
Author(s):  
Jo-Ann McClure ◽  
Steven M. Shideler ◽  
Kunyan Zhang
Keyword(s):  
Staphylococcus Aureus ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
Clonal Complex ◽  
Virulent Strain ◽  
Sequence Type ◽  
Genome Sequences ◽  
Methicillin Resistant ◽  
Content Type ◽  
Mrsa Strains ◽  
Highly Virulent

Methicillin-resistant Staphylococcus aureus (MRSA) clonal complex 8 (CC8) sequence type 239 (ST239) represents a predominant hospital-associated MRSA sublineage present worldwide. The Canadian epidemic MRSA strains CMRSA3 and CMRSA6 are moderately virulent members of this group but are closely related to the highly virulent strain TW20.

scholarly journals Fluoroquinolone Metalloantibiotics: A Promising Approach against Methicillin-Resistant Staphylococcus aureus

2020 ◽  
Vol 17 (9) ◽  
pp. 3127 ◽  
Author(s):  
Mariana Ferreira ◽  
Lucinda J. Bessa ◽  
Carla F. Sousa ◽  
Peter Eaton ◽  
Dafne Bongiorno ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Antimicrobial Activity ◽  
Mechanism Of Action ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
Multidrug Resistant ◽  
Clinical Isolates ◽  
Synergistic Activity ◽  
Divalent Metal Ions ◽  
Methicillin Resistant ◽  
Force Microscopy

Fluoroquinolones (FQs) are antibiotics commonly used in clinical practice, although nowadays they are becoming ineffective due to the emergence of several mechanisms of resistance in most bacteria. The complexation of FQs with divalent metal ions and phenanthroline (phen) is a possible approach to circumvent antimicrobial resistance, since it forms very stable complexes known as metalloantibiotics. This work is aimed at determining the antimicrobial activity of metalloantibiotics of Cu(II)FQphen against a panel of multidrug-resistant (MDR) clinical isolates and to clarify their mechanism of action. Minimum inhibitory concentrations (MICs) were determined against MDR isolates of Escherichia coli, Pseudomonas aeruginosa and methicillin-resistant Staphylococcus aureus (MRSA). Metalloantibiotics showed improved antimicrobial activity against several clinical isolates, especially MRSA. Synergistic activity was evaluated in combination with ciprofloxacin and ampicillin by the disk diffusion and checkerboard methods. Synergistic and additive effects were shown against MRSA isolates. The mechanism of action was studied though enzymatic assays and atomic force microscopy (AFM) experiments. The results indicate a similar mechanism of action for FQs and metalloantibiotics. In summary, metalloantibiotics seem to be an effective alternative to pure FQs against MRSA. The results obtained in this work open the way to the screening of metalloantibiotics against other Gram-positive bacteria.

scholarly journals What Is the Origin of Livestock-Associated Methicillin-Resistant Staphylococcus aureus Clonal Complex 398 Isolates from Humans without Livestock Contact? An Epidemiological and Genetic Analysis

2015 ◽  
Vol 53 (6) ◽  
pp. 1836-1841 ◽  
Author(s):  
W. S. N. Lekkerkerk ◽  
W. J. B. van Wamel ◽  
S. V. Snijders ◽  
R. J. Willems ◽  
E. van Duijkeren ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
Clonal Complex ◽  
Unknown Origin ◽  
Human Origin ◽  
Methicillin Resistant ◽  
Content Type ◽  
Veal Calves ◽  
Indirect Transmission ◽  
Outbreak Isolate

Fifteen percent of all methicillin-resistantStaphylococcus aureus(MRSA) clonal complex 398 (CC398) human carriers detected in The Netherlands had not been in direct contact with pigs or veal calves. To ensure low MRSA prevalence, it is important to investigate the likely origin of this MRSA of unknown origin (MUO). Recently, it was shown that CC398 strains originating from humans and animals differ in the presence of specific mobile genetic elements (MGEs). We hypothesized that determining these specific MGEs in MUO isolates and comparing them with a set of CC398 isolates of various known origin might provide clues to their origin. MUO CC398 isolates were compared to MRSA CC398 isolates obtained from humans with known risk factors, a MRSA CC398 outbreak isolate, livestock associated (LA) MRSA CC398 isolates from pigs, horses, chickens, and veal calves, and five methicillin-susceptibleStaphylococcus aureus(MSSA) CC398 isolates of known human origin. All strains werespatyped, and the presence or absence of,scn,chp, φ3int, φ6int, φ7int,rep7,rep27, andcadDXwas determined by PCRs. The MRSA CC398 in humans, MUO, or MRSA of known origin (MKO) resembled MRSA CC398 as found in pigs and not MSSA CC398 as found in humans. The distinct human MSSA CC398spatype, t571, was not present among our MRSA CC398 strains; MRSA CC398 was tetracycline resistant and carried no φ3 bacteriophage withscnandchp. We showed by simple PCR means that human MUO CC398 carriers carried MRSA from livestock origin, suggestive of indirect transmission. Although the exact transmission route remains unknown, direct human-to-human transmission remains a possibility as well.

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