scholarly journals Provisional Use of CLSI-Approved Quality Control Strains for Antimicrobial Susceptibility Testing of Mycoplasma (‘Mesomycoplasma’) hyorhinis

2021 ◽  
Vol 9 (9) ◽  
pp. 1829
Author(s):  
Lisa Käbisch ◽  
Anne-Kathrin Schink ◽  
Corinna Kehrenberg ◽  
Stefan Schwarz
Keyword(s):  
Quality Control ◽  
Antimicrobial Susceptibility ◽  
Antimicrobial Agents ◽  
Susceptibility Testing ◽  
Antimicrobial Treatment ◽  
Antimicrobial Susceptibility Testing ◽  
Broth Microdilution ◽  
Minimal Inhibitory Concentrations ◽  
Microtiter Plates ◽  
And Staphylococcus Aureus

Antimicrobial susceptibility testing (AST) should be conducted in a standardized manner prior to the start of an antimicrobial treatment. For fastidious bacteria, such as porcine Mycoplasma (‘Mesomycoplasma’) spp., specifically M. hyorhinis, neither guidelines or standards for the performance of AST, nor quality control strains for the validation of AST results are approved by organizations like the Clinical and Laboratory Standards Institute (CLSI) or the European Committee on Antimicrobial Susceptibility Testing (EUCAST). The CLSI- and EUCAST-approved quality control strains Enterococcus faecalis ATCC 29212 and Staphylococcus aureus ATCC 29213 were chosen to validate AST by broth microdilution using modified Friis broth, developed as growth medium for porcine Mycoplasma (‘Mesomycoplasma’) spp. The antimicrobial agents doxycycline, enrofloxacin, erythromycin, florfenicol, gentamicin, marbofloxacin, tetracycline, tiamulin, tilmicosin, tulathromycin, and tylosin were examined using customized SensititreTM microtiter plates. Minimal inhibitory concentrations, determined after 24, 48, and 72 h, were mostly within the CLSI-approved quality control ranges for defined antimicrobial agents. We propose the use of the combination of E. faecalis ATCC 29212 and S. aureus ATCC 29213 as surrogate quality control strains for the validation of future AST results obtained for M. hyorhinis by broth microdilution using modified Friis broth.

scholarly journals The Frequency of Methicillin-Resistant Staphylococcus aureus and Coagulase Gene Polymorphism in Egypt

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Hend M. Abdulghany ◽  
Rasha M. Khairy
Keyword(s):  
Staphylococcus Aureus ◽  
Gene Polymorphism ◽  
Antimicrobial Susceptibility ◽  
Antimicrobial Agents ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
Susceptibility Testing ◽  
Antimicrobial Susceptibility Testing ◽  
Methicillin Resistant ◽  
Microbiological Methods ◽  
Rflp Typing

The current study aimed to use Coagulase gene polymorphism to identify methicillin-resistant Staphylococcus aureus (MRSA) subtypes isolated from nasal carriers in Minia governorate, Egypt, evaluate the efficiency of these methods in discriminating variable strains, and compare these subtypes with antibiotypes. A total of 400 specimens were collected from nasal carriers in Minia governorate, Egypt, between March 2012 and April 2013. Fifty-eight strains (14.5%) were isolated and identified by standard microbiological methods as MRSA. The identified isolates were tested by Coagulase gene RFLP typing. Out of 58 MRSA isolates 15 coa types were classified, and the amplification products showed multiple bands (1, 2, 3, 4, 5, and 8 bands). Coagulase gene PCR-RFLPs exhibited 10 patterns that ranged from 1 to 8 fragments with AluI digestion. Antimicrobial susceptibility testing with a panel of 8 antimicrobial agents showed 6 different antibiotypes. Antibiotype 1 was the most common phenotype with 82.7%. The results have demonstrated that many new variants of the coa gene are present in Minia, Egypt, different from those reported in the previous studies. So surveillance of MRSA should be continued.

scholarly journals Analysis of Whole-Genome Sequences for the Prediction of Penicillin Resistance and β-Lactamase Activity inBacillus anthracis

mSystems ◽  
2018 ◽  
Vol 3 (6) ◽  
Author(s):  
A. S. Gargis ◽  
H. P. McLaughlin ◽  
A. B. Conley ◽  
C. Lascols ◽  
P. A. Michel ◽  
...  
Keyword(s):  
Sequence Analysis ◽  
Antimicrobial Susceptibility ◽  
Sigma Factor ◽  
Antimicrobial Agents ◽  
Susceptibility Testing ◽  
Antimicrobial Susceptibility Testing ◽  
Penicillin Resistance ◽  
Whole Genome ◽  
Activity Levels ◽  
Content Type

ABSTRACTPenicillin (PEN) is a low-cost option for anthrax treatment, but naturally occurring resistance has been reported. β-Lactamase expression (bla1,bla2) inBacillus anthracisis regulated by a sigma factor (SigP) and its cognate anti-sigma factor (RsiP). Mutations leading to truncation of RsiP were previously described as a basis for PEN resistance. Here, we analyze whole-genome sequencing (WGS) data and compare the chromosomalsigP-bla1regions from 374B. anthracisstrains to determine the frequency of mutations, identify mutations associated with PEN resistance, and evaluate the usefulness of WGS for predicting PEN resistance. Few (3.5%) strains contained at least 1 of 11 different mutations insigP,rsiP, orbla1.Nine of these mutations have not been previously associated with PEN resistance. Four strains showed PEN resistance (PEN-R) by conventional broth microdilution, including 1 strain with a novel frameshift inrsiP. One strain that carries the samersiPframeshift mutation as that found previously in a PEN-R strain showed a PEN-susceptible (PEN-S) phenotype and exhibited decreasedbla1andbla2transcription. An unexpectedly small colony size, a reduced growth rate, and undetectable β-lactamase activity levels (culture supernatant and cell lysate) were observed in this PEN-S strain. Sequence analysis revealed mutations in genes associated with growth defects that may contribute to this phenotype. WhileB. anthracisrsiPmutations cannot be exclusively used to predict resistance, four of the five strains withrsiPmutations were PEN-R. Therefore, theB. anthracissigP-bla1region is a useful locus for WGS-based PEN resistance prediction, but phenotypic testing remains essential.IMPORTANCEDetermination of antimicrobial susceptibility ofB. anthracisis essential for the appropriate distribution of antimicrobial agents for postexposure prophylaxis (PEP) and treatment of anthrax. Analysis of WGS data allows for the rapid detection of mutations in antimicrobial resistance (AMR) genes in an isolate, but the presence of a mutation in an AMR gene does not always accurately predict resistance. As mutations in the anti-sigma factor RsiP have been previously associated with high-level penicillin resistance in a limited number of strains, we investigated WGS assemblies from 374 strains to determine the frequency of mutations and performed functional antimicrobial susceptibility testing. Of the five strains that contained mutations inrsiP, only four were PEN-R by functional antimicrobial susceptibility testing. We conclude that while sequence analysis of this region is useful for AMR prediction inB. anthracis, genetic analysis should not be used exclusively and phenotypic susceptibility testing remains essential.

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