Abstract
The transmission between community-associated (CA-) and healthcare-associated (HA-) methicillin-resistant Staphylococcus aureus (MRSA) has increased the challenge of infection control. To understand the clonal evolution and transmission of MRSA isolates, we compared the characteristics of 175 CA-MRSA and 660 HA-MRSA strains at a Chinese tertiary hospital in 2012–2017. Antibiotic susceptibility was performed on VITEK system, the genetic background of the isolates was characterized by SCCmec, spa, and MLST typing, while virulence determinants were screened using conventional PCR. Although more than 70% of the CA-MRSA isolates were erythromycin and clindamycin resistant, CA-MRSA was more susceptible than HA-MRSA to most of the antibiotics tested. ST239-MRSA-III-t030 (30%) was the most prevalent clone among HA-MRSA, while ST59-MRSA-IVa-t437 (28.8%) was the major clone among CA-MRSA. Notably, ST59-MRSA-IVa-t437 accounted for 6.7% of the chosen HA-MRSA isolates. Additionally, difference in virulence gene content was found between the CA- and HA-MRSA strains. In conclusion, epidemiological characteristics were largely different between CA- and HA-MRSA. Although ST239-MRSA-III-t030 is still the predominant clone among HA-MRSA, the community clone ST59-MRSA-IVa-t437 has the potential of becoming an essential part of HA-MRSA in the region tested.
Highlights
Staphylococcus aureus (S. aureus) is one of the most frequent causal pathogens of both community- and hospital-acquired infections[1]
83 (47.4%) CA-methicillinresistant Staphylococcus aureus (MRSA) and 351 (53.2%) HA-MRSA strains were obtained from male patients, and the remaining isolates were obtained from female patients
Considering the serious clinical consequences of MRSA infection and difference in suitable antimicrobial treatments for CA- and HA-MRSA14, it is necessary to distinguish between these two types of S. aureus, and to understand their molecular characteristics, antimicrobial susceptibility patterns and virulence gene profiles
Summary
Staphylococcus aureus (S. aureus) is one of the most frequent causal pathogens of both community- and hospital-acquired infections[1]. Most CA-MRSA isolates carry the lukSF-PV (alias pvl) genes encoding a bi-component toxin cytolytic toward neutrophils[10,11], the correlation between the presence of lukSF-PV genes and the clinical outcome remains controversial[11]. It is a well-established fact that S. aureus is notorious for its ability to produce a series of virulence factors. Associated lineages, and revealed that Agr, α-toxin, and PSMα significantly contributed to the pathogenesis of ST59 CA-MRSA infections It remains to be seen whether other virulence factors produced by S. aureus contribute to CA-MRSA infections. A comparison of virulence gene profiles between HA- and CA-MRSA isolates may help to understand the genetic basis underlying the possible association between some CA-MRSA infections and poor clinical outcome
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