Genetic analysis of type 5 capsular polysaccharide expression by Staphylococcus aureus.

Background. Global concerns have been raised due to upward trend of Vancomycin Intermediate Staphylococcus aureus (VISA) and Vancomycin Resistant Staphylococcus aureus (VRSA) reports which mean casting doubt on the absolute effectiveness of the last line of antibiotic treatment for S. aureus, vancomycin. Hence, epidemiological evaluation can improve global health care policies. Methodology. 171 Isolates of Staphylococcus aureus were collected from different types of clinical samples in selected hospitals in Isfahan, Mashhad, and Tehran, Iran. Then, they were evaluated by agar screening, disk diffusion, and MIC method to determine their resistance to vancomycin and methicillin. The isolated VISA strains were then confirmed with genetic analysis by the evaluation of mecA and vanA genes, SCCmec, agr, and spa type, and also toxin profiles. MLST was also performed. Results and Conclusion. Our data indicated that 67% of isolated S. aureus strains were resistant to methicillin. Furthermore, five isolates (2.9%) had intermediate resistance to vancomycin (VISA). In contrast to usual association of VISA with MRSA strains, we found two isolates of MSSA-VISA. Therefore, our data suggests a probable parallel growing trend of VISA towards MSSA, along with MRSA strains. However, more samples are required to confirm these primarily data. Moreover, genetic analysis of the isolated VISA strains revealed that these strains are endemic Asian clones.

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Whole Genome Sequencing and Complete Genetic Analysis Reveals Novel Pathways to Glycopeptide Resistance in Staphylococcus aureus

PLoS ONE ◽

10.1371/journal.pone.0021577 ◽

2011 ◽

Vol 6 (6) ◽

pp. e21577 ◽

Cited By ~ 45

Author(s):

Adriana Renzoni ◽

Diego O. Andrey ◽

Ambre Jousselin ◽

Christine Barras ◽

Antoinette Monod ◽

...

Keyword(s):

Staphylococcus Aureus ◽

Genetic Analysis ◽

Whole Genome Sequencing ◽

Genome Sequencing ◽

Whole Genome ◽

Glycopeptide Resistance

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Genetic Analysis of a Vancomycin-Resistant Staphylococcus aureus Strain Isolated in Iran

mBio ◽

10.1128/mbio.00442-12 ◽

2012 ◽

Vol 3 (6) ◽

Cited By ~ 1

Author(s):

Amir Azimian ◽

Seyed Asghar Havaei ◽

Hosein Fazeli ◽

Mahmood Naderi ◽

Kiarash Ghazvini ◽

...

Keyword(s):

Staphylococcus Aureus ◽

Genetic Analysis ◽

Aureus Strain ◽

Vancomycin Resistant

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Staphylococcus aureus CcpA Affects Virulence Determinant Production and Antibiotic Resistance

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.50.4.1183-1194.2006 ◽

2006 ◽

Vol 50 (4) ◽

pp. 1183-1194 ◽

Cited By ~ 127

Author(s):

Kati Seidl ◽

Martin Stucki ◽

Martin Ruegg ◽

Christiane Goerke ◽

Christiane Wolz ◽

...

Keyword(s):

Gene Expression ◽

Staphylococcus Aureus ◽

Capsular Polysaccharide ◽

Protein A ◽

Virulence Gene ◽

Exponential Growth Phase ◽

Virulence Determinants ◽

Resistance Level ◽

Virulence Gene Expression ◽

Oxacillin Resistance

ABSTRACT Carbon catabolite protein A (CcpA) is known to function as a major regulator of gene expression in different gram-positive organisms. Deletion of the ccpA homologue (saCOL1786) in Staphylococcus aureus was found to affect growth, glucose metabolization, and transcription of selected virulence determinants. In liquid culture, deletion of CcpA decreased the growth rate and yield; however, the effect was only transient during the exponential-growth phase as long as glucose was present in the medium. Depletion of glucose and production of lactate was delayed, while the level of excretion of acetate was less affected and was even higher in the mutant culture. On solid medium, in contrast, growth of the ΔccpA mutant resulted in smaller colonies containing a lower number of CFU per colony. Deletion of CcpA had an effect on the expression of important virulence factors of S. aureus by down-regulating RNAIII, the effector molecule of the agr locus, and altering the transcription patterns of hla, encoding α-hemolysin, and spa, encoding protein A. CcpA inactivation markedly reduced the oxacillin resistance levels in the highly methicillin-resistant S. aureus strain COLn and the teicoplanin resistance level in a glycopeptide-intermediate-resistant S. aureus strain. The presence of CcpA in the capsular polysaccharide serotype 5 (CP5)-producing strain Newman abolished capsule formation and decreased cap operon transcription in the presence of glucose. The staphylococcal CcpA thus not only is involved in the regulation of carbon metabolism but seems to function as a modulator of virulence gene expression as well.

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