<i>Staphylococcus aureus</i>mutants lacking cell wall-bound protein A found in isolates from bacteraemia, MRSA infection and a healthy nasal carrier

Sørum, Marit; Sangvik, Maria; Stegger, Marc; Olsen, Renate Slind; Johannessen, Mona; Skov, Robert; Sollid, Johanna U. E.

doi:10.1111/2049-632x.12017

Cited by 15 publications

(10 citation statements)

References 34 publications

(35 reference statements)

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“…Of these, 8 isolates demonstrated bands on amplification of the spa fragment with the published forward primer as well as an alternate forward primer (Molla et al, 2012). However, the RIDOM StaphType software could not assign spa types, possibly due to deviating repeats as demonstrated in previous studies (Baum et al, 2009; Sörum et al, 2013). The remaining 3 isolates demonstrated double bands for the spa gene as observed in a study conducted by Shakeri et al (2010), which could not give spa types even after three attempts on PCR or purification of bands from an agarose gel.…”

Section: Resultsmentioning

confidence: 61%

Antimicrobial resistance and molecular epidemiology ofStaphylococcus aureusfrom Ulaanbaatar, Mongolia

Nair

Hanson

Kondratowicz

et al. 2013

PeerJ

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This study aimed to characterize Staphylococcus aureus (S. aureus) strains isolated from human infections in Mongolia. Infection samples were collected at two time periods (2007–08 and 2011) by the National Center for Communicable Diseases (NCCD) in Ulaanbaatar, Mongolia. S. aureus isolates were characterized using polymerase chain reaction (PCR) for mecA, PVL, and sasX genes and tested for agr functionality. All isolates were also spa typed. A subset of isolates selected by frequency of spa types was subjected to antimicrobial susceptibility testing and multilocus sequence typing. Among 251 S. aureus isolates, genotyping demonstrated methicillin resistance in 8.8% of isolates (22/251). Approximately 28% of the tested S. aureus isolates were observed to be multidrug resistant (MDR). Sequence type (ST) 154 (spa t667) was observed to be a strain with high virulence potential, as all isolates for this spa type were positive for PVL, had a functional agr system and 78% were MDR. S. aureus isolates of ST239 (spa t037) were observed to cause infections and roughly 60% had functional agr system with a greater proportion being MDR. Additionally, new multilocus sequence types and new spa types were identified, warranting continued surveillance for S. aureus in this region.

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Section: Resultsmentioning

confidence: 61%

Antimicrobial resistance and molecular epidemiology ofStaphylococcus aureusfrom Ulaanbaatar, Mongolia

Nair

Hanson

Kondratowicz

et al. 2013

PeerJ

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“…Protein A is a cell surface protein of the gram-positive, pathogenic bacterium Staphylococcus aureus and exists in both cell wall-bound and secreted forms [ 1 ]. Staph .…”

Section: Introductionmentioning

confidence: 99%

In vitro Selection and Interaction Studies of a DNA Aptamer Targeting Protein A

Stoltenburg

Schubert²,

Strehlitz

2015

PLoS ONE

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A new DNA aptamer targeting Protein A is presented. The aptamer was selected by use of the FluMag-SELEX procedure. The SELEX technology (Systematic Evolution of Ligands by EXponential enrichment) is widely applied as an in vitro selection and amplification method to generate target-specific aptamers and exists in various modified variants. FluMag-SELEX is one of them and is characterized by the use of magnetic beads for target immobilization and fluorescently labeled oligonucleotides for monitoring the aptamer selection progress. Structural investigations and sequence truncation experiments of the selected aptamer for Protein A led to the conclusion, that a stem-loop structure at its 5’-end including the 5’-primer binding site is essential for aptamer-target binding. Extensive interaction analyses between aptamer and Protein A were performed by methods like surface plasmon resonance, MicroScale Thermophoresis and bead-based binding assays using fluorescence measurements. The binding of the aptamer to its target was thus investigated in assays with immobilization of one of the binding partners each, and with both binding partners in solution. Affinity constants were determined in the low micromolar to submicromolar range, increasing to the nanomolar range under the assumption of avidity. Protein A provides more than one binding site for the aptamer, which may overlap with the known binding sites for immunoglobulins. The aptamer binds specifically to both native and recombinant Protein A, but not to other immunoglobulin-binding proteins like Protein G and L. Cross specificity to other proteins was not found. The application of the aptamer is directed to Protein A detection or affinity purification. Moreover, whole cells of Staphylococcus aureus, presenting Protein A on the cell surface, could also be bound by the aptamer.

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“…Of these, 8 isolates demonstrated bands on amplification of the spa fragment with the published forward primer as well as an alternate forward primer (Molla et al 2012). However, the RIDOM StaphType software could not assign spa types, possibly due to deviating repeats as demonstrated in previous studies (Baum et al 2009;Sorum et al 2013). The remaining 3 isolates demonstrated double bands for the spa gene as observed in a study conducted by Shakeri et al (Shakeri et al 2010), which could not give spa types even after three attempts on PCR or purification of bands from an agarose gel.…”

Section: Cary Ncmentioning

confidence: 75%

Peer Review #1 of "Antimicrobial resistance and molecular epidemiology of Staphylococcus aureus from Ulaanbaatar, Mongolia (v0.1)"

2013

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This study aimed to characterize Staphylococcus aureus (S. aureus) strains isolated from human infections in Mongolia. Infection samples were collected at two time periods (2007-08 and 2011) by the National Center for Communicable Diseases (NCCD) in Ulaanbaatar, Mongolia. S. aureus isolates were characterized using polymerase chain reaction (PCR) for mecA, PVL, and sasX genes and tested for agr functionality. All isolates were also spa typed. A subset of isolates selected by frequency of spa types was subjected to antimicrobial susceptibility testing and multilocus sequence typing. Among 251 S. aureus isolates, genotyping demonstrated methicillin resistance in 8.8% of isolates (22/251). Approximately 28% of the tested S. aureus isolates were observed to be multidrug resistant (MDR). Sequence type (ST) 154 (spa t667) was observed to be a strain with high virulence potential, as all isolates for this spa type were positive for PVL, had a functional agr system and 78% were MDR. S. aureus isolates of ST239 (spa t037) were observed to cause infections and roughly 60% had functional agr system with a greater proportion being MDR. Additionally, new multilocus sequence types and new spa types were identified, warranting continued surveillance for S. aureus in this region.

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Staphylococcus aureusmutants lacking cell wall-bound protein A found in isolates from bacteraemia, MRSA infection and a healthy nasal carrier

Cited by 15 publications

References 34 publications

Antimicrobial resistance and molecular epidemiology ofStaphylococcus aureusfrom Ulaanbaatar, Mongolia

Antimicrobial resistance and molecular epidemiology ofStaphylococcus aureusfrom Ulaanbaatar, Mongolia

In vitro Selection and Interaction Studies of a DNA Aptamer Targeting Protein A

Peer Review #1 of "Antimicrobial resistance and molecular epidemiology of Staphylococcus aureus from Ulaanbaatar, Mongolia (v0.1)"

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