Dataset Information

Identification of fusB-mediated fusidic acid resistance islands in Staphylococcus epidermidis isolates.

ABSTRACT: To understand the high prevalence of fusB genes in fusidic acid-resistant Staphylococcus epidermidis, analysis of resistance elements in 34 isolates was performed. First, sequence analysis of the aj1-LP-fusB region indicated that at least three types were present. Type I contained full-length aj1, type II contained a partial aj1 truncated from nucleotide position 93 to 421, and type III contained a more truncated aj1 that retained only the last 37 bp. Isolates with type I or type II aj1 displayed slightly higher levels of resistance to fusidic acid (MICs, 8 to 32 ?g/ml) than did those with type III aj1 (MICs, 4 to 16 ?g/ml). Subsequent sequencing of the flanking regions of fusB from four selected isolates carrying different types of aj1-LP-fusB regions revealed that the fusB genes were all located on phage-related resistance islands (RIs), referred to as SeRI(fusB)(-2793), SeRI(fusB)(-704), SeRI(fusB)(-5907), and SeRI(fusB)(-7778), respectively. Among them, three islands (SeRI(fusB)(-2793), SeRI(fusB)(-704), and SeRI(fusB)(-5907)) were located downstream of groEL (corresponding to the 44-min position based on Staphylococcus aureus whole genomic sequences), and one (SeRI(fusB)(-7778)) was located downstream of rpsR (corresponding to the 8-min position). All of the RIs were inserted into integrase-recognized att sites. Among 34 isolates, the insertion sites of fusB RIs were mostly (28/34, 82%) located downstream of groEL and two were located downstream of rpsR, but four remained unidentified. The pulsotype distribution indicated that fusB-containing S. epidermidis isolates were heterogeneous. In conclusion, the fusB resistance determinant in S. epidermidis was highly associated with phage-related RIs. This is the first report of fusB RI in S. epidermidis.

SUBMITTER: Chen HJ

PROVIDER: S-EPMC3232760 | biostudies-literature | 2011 Dec

REPOSITORIES: biostudies-literature

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Identification of fusB-mediated fusidic acid resistance islands in Staphylococcus epidermidis isolates.

Chen Hsiao-Jan HJ Tsai Jui-Chang JC Hung Wei-Chun WC Tseng Sung-Pin SP Hsueh Po-Ren PR Teng Lee-Jene LJ

Antimicrobial agents and chemotherapy 20111003 12

To understand the high prevalence of fusB genes in fusidic acid-resistant Staphylococcus epidermidis, analysis of resistance elements in 34 isolates was performed. First, sequence analysis of the aj1-LP-fusB region indicated that at least three types were present. Type I contained full-length aj1, type II contained a partial aj1 truncated from nucleotide position 93 to 421, and type III contained a more truncated aj1 that retained only the last 37 bp. Isolates with type I or type II aj1 displaye ...[more]

PMID: 21968364

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Project description:Staphylococcus epidermidis is a leading opportunistic pathogen causing nosocomial infections that is notable for its ability to form a biofilm and for its high rates of antibiotic resistance. It serves as a reservoir of multiple antimicrobial resistance genes that spread among the staphylococcal population by horizontal gene transfer such as transduction. While phage-mediated transduction is well studied in Staphylococcus aureus, S. epidermidis transducing phages have not been described in detail yet. Here, we report the characteristics of four phages, 27, 48, 456, and 459, previously used for S. epidermidis phage typing, and the newly isolated phage E72, from a clinical S. epidermidis strain. The phages, classified in the family Siphoviridae and genus Phietavirus, exhibited an S. epidermidis-specific host range, and together they infected 49% of the 35 strains tested. A whole-genome comparison revealed evolutionary relatedness to transducing S. aureus phietaviruses. In accordance with this, all the tested phages were capable of transduction with high frequencies up to 10-4 among S. epidermidis strains from different clonal complexes. Plasmids with sizes from 4 to 19 kb encoding resistance to streptomycin, tetracycline, and chloramphenicol were transferred. We provide here the first evidence of a phage-inducible chromosomal island transfer in S. epidermidis Similarly to S. aureus pathogenicity islands, the transfer was accompanied by phage capsid remodeling; however, the interfering protein encoded by the island was distinct. Our findings underline the role of S. epidermidis temperate phages in the evolution of S. epidermidis strains by horizontal gene transfer, which can also be utilized for S. epidermidis genetic studies.IMPORTANCE Multidrug-resistant strains of S. epidermidis emerge in both nosocomial and livestock environments as the most important pathogens among coagulase-negative staphylococcal species. The study of transduction by phages is essential to understanding how virulence and antimicrobial resistance genes spread in originally commensal bacterial populations. In this work, we provide a detailed description of transducing S. epidermidis phages. The high transduction frequencies of antimicrobial resistance plasmids and the first evidence of chromosomal island transfer emphasize the decisive role of S. epidermidis phages in attaining a higher pathogenic potential of host strains. To date, such importance has been attributed only to S. aureus phages, not to those of coagulase-negative staphylococci. This study also proved that the described transducing bacteriophages represent valuable genetic modification tools in S. epidermidis strains where other methods for gene transfer fail.

Project description:The significant increase in resistance of methicillin-resistant Staphylococcus aureus (MRSA) to fusidic acid (FA) is a worrying public concern. However, the data on the prevalence of FA-resistant MRSA isolates in China is still limited. This study aims to investigate the prevalence of FA resistance and resistance determinants among MRSA isolates from six tertiary hospitals in different regions of China between 2016 and 2020. The antimicrobial susceptibility of MRSA isolates was performed by disk diffusion test and broth microdilution method. Whole-genome sequencing was conducted to evaluate the determinants of FA resistance and molecular characterization of FA-resistant MRSA isolates. In this study, a total of 74 (74/457, 16.2%) isolates were identified to be FA-resistant among 457 non-duplicate MRSA isolates. The prevalence of 74 FA-resistant isolates was as follows: Hubei (28/70, 40%), Shanghai (18/84, 21.4%), Jiangxi (7/58, 12.1%), Inner Mongolia Autonomous Region (6/38, 15.8%), Guangdong (12/112, 10.7%), and Sichuan (3/95, 3.2%). The mutations in fusA were present in 79.7% (59/74) of FA-resistant MRSA isolates, with 54 (54/74, 73%) having L461K mutation and conferring high-level resistance [Minimum Inhibitory Concentration (MIC)>128 μg/ml]. Acquired gene, fusB, with low-level resistance (MIC <16 μg/ml) was found in 20.3% (15/74) FA-resistant MRSA isolates. ST5-MRSA-II-t2460 was the most prevalence clone with high-level resistance, accounting for 51.4% (38/74), which was distributed in Hubei (24/28, 85.7%), Inner Mongolia Autonomous Region (4/6, 66.7%), Shanghai (7/18, 38.9%), and Guangdong (3/12, 25%). ST630-t4549 MRSA isolates with low-level resistance were the most common in Jiangxi (3/7, 42.9%) and Sichuan (2/3, 66.7%). In brief, the prevalence of FA resistance among MRSA isolates in China was relatively high with geographic differences. High-level FA resistance was associated mostly with fusA mutations, especially the L461K mutation, whereas fusB usually conferred the low-level resistance to FA. The spread of ST5-MRSA-II-t2460 clone with high-level resistance to FA contributed greatly to the increase of FA-resistant MRSA isolates in most regions, especially in Hubei.

Dataset Information

Identification of fusB-mediated fusidic acid resistance islands in Staphylococcus epidermidis isolates.

Publications

Identification of fusB-mediated fusidic acid resistance islands in Staphylococcus epidermidis isolates.

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