Molecular characteristics and virulence factors in methicillin-susceptible, resistant, and heterogeneous vancomycin-intermediate Staphylococcus aureus from central-southern China

Liu, Cailin; Chen, Zhongju; Sun, Ziyong; Feng, Xin; Zou, Ming-Xiang; Cao, Wei; Wang, Shanmei; Zeng, Jing; Wang, Yue; Sun, Mingyue

doi:10.1016/j.jmii.2014.03.003

Cited by 51 publications

(50 citation statements)

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“…Further, reports of MRSA from Korea showed that 11 out of 17 mastitic strains from five different farms belonged to a single spa type (t324) and report from the USA found that all strains (n = 4) belonged to similar spa (t121) type [8]-[9]. Among the strain types that we found, spa types t2526 and t9602 have been previously reported in human infections [37]-[38]. Other spa types were well documented in both human and bovine infections or in bovine mastitis except spa types, t3731 and t8137 for which no published reports could be found.…”

Section: Discussionsupporting

confidence: 50%

Prevalence and Characterization of Oxacillin Susceptible mecA-Positive Clinical Isolates of Staphylococcus aureus Causing Bovine Mastitis in India

et al. 2016

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Bovine mastitis caused by multidrug resistant Staphylococcus aureus is a huge problem reported worldwide, resulting in prolonged antibiotic treatment and death of livestock. The current study is focused on surveillance of antibiotic susceptibility along with genotypic and phenotypic characterization of the pathogenic S. aureus strains causing mastitis in India. One hundred and sixty seven milk samples were collected from mastitis-affected cows from different farms in India resulting in thirty nine isolated S. aureus strains. Antibiotic sensitivity profiling revealed the majority of the strains (n = 24) to be multidrug resistant and eleven strains showed reduced susceptibility to vancomycin (MICs = 2μg/ml). All strains were oxacillin sensitive, but 19 strains were positive for the mecA gene, which revealed the occurrence of oxacillin susceptible mecA positive strains (OS-MRSA) for the first time from India. Additionally, 32 strains were positive for the pvl gene, a virulence determinant; of these 17 were also OS-MRSA strains. Molecular characterization based on multilocus sequence typing (MLST), spa typing, agr typing and SCCmec classification revealed strains belonging to different groups. Moreover, strains showed spa types (t2526, t9602) and MLST sequence types, ST-72, ST-88 and ST-239 which have been earlier reported in human infections. The prevalence of OS-MRSA strains indicates the importance of including both the genetic and phenotypic tests in characterizing S. aureus strains. Increased genotypic variability with strain related to human infections and pvl positive isolates indicates a worrisome situation with the possibility of bilateral transfer.

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Section: Discussionsupporting

confidence: 50%

Prevalence and Characterization of Oxacillin Susceptible mecA-Positive Clinical Isolates of Staphylococcus aureus Causing Bovine Mastitis in India

et al. 2016

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“…A study conducted in Minnesota and Wisconsin found that CA-MRSA strains were likely to contain the lukED locus (~99%), whereas MSSA strains collected from either symptomatic patients or asymptomatically colonized human subjects were less likely to contain the locus (44–77%) [63]. These numbers are similar to previous studies that estimated 87–93% carriage rate in Japanese clinically acquired strains (no drug-resistance noted) and 88–99% in CA-MRSA strains acquired around the world [62, 86, 88]. Interestingly, the lukED locus is also present in ~90% of S. aureus strains collected from cows with subclinical to severe mastitis, supporting a possible role for LukED in virulence or infectivity in different host species [84, 89].…”

Section: Overviewsupporting

confidence: 82%

Staphylococcus aureus pore-forming toxins: The interface of pathogen and host complexity

Seilie

Wardenburg

2017

Seminars in Cell & Developmental Biology

173

136

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Staphylococcus aureus is a prominent human pathogen capable of infecting a variety of host species and tissue sites. This versatility stems from the pathogen’s ability to secrete diverse host-damaging virulence factors. Among these factors, the S. aureus pore-forming toxins (PFTs), α-toxin and the bicomponent leukocidins, have garnered much attention for their ability to lyse cells at low concentrations and modulate disease severity. Although many of these toxins were discovered nearly a century ago, their host cell specificity has only been elucidated over the past five to six years, starting with the discovery of the eukaryotic receptor for α-toxin and rapidly followed by identification of the leukocidin receptors. The identification of these receptors has revealed the species- and cell type-specificity of toxin binding, and provided insight into non-lytic effects of PFT intoxication that contribute to disease pathogenesis.

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“…On the other hand, the LCM isolates were SCC mec type IV or V and nearly half had PVL genes, which indicated genetic relatedness to community-acquired MRSA (CA-MRSA) isolates that have a higher prevalence of PVL (Liu et al, 2015). Therefore, the tested isolates somewhat represent the major types of clinical MRSA isolates.…”

Section: Discussionmentioning

confidence: 99%

Cephalosporin-Glycopeptide Combinations for Use against Clinical Methicillin-Resistant Staphylococcus aureus Isolates: Enhanced In vitro Antibacterial Activity

et al. 2017

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The empirical combination of both a beta-lactam and glycopeptide to counter potential staphylococcal pathogens may improve the clinical outcomes for cases of Staphylococcus aureus bacteremia. We reported comparative in vitro studies of combination effects of different cephalosporins (i.e., cefazolin, cefmetazole, cefotaxime, and cefepime) combined with glycopeptides for 34 randomly selected methicillin-resistant S. aureus (MRSA) isolates by three methods, including the checkerboard, time-killing, and combination MIC measurement methods. Thirteen SCCmec type III isolates with a cefazolin MIC of ≥ 128 μg/mL were classified as the high-cefazolin MIC (HCM) group, whereas 13 SCCmec type IV and 8 SCCmec type V isolates were classified as the low-cefazolin MIC (LCM) group. With the checkerboard method, synergism was present for vancomycin-based combinations at 30.8–69.2 and 13.6–66.7%, as well as teicoplanin-based combinations of 38.5–84.6 and 0–47.6%, of the HCM and LCM isolates, respectively. No antagonism was noted. The in vitro inhibitory activity was evident even at a low concentration of 1/512x MIC of cephalosporin combined with sub-inhibitory concentrations (1/2x MIC) of a glycopeptide. With time-killing assays, synergism was noted at 1/2x or 1x susceptible breakpoint concentrations (SBCs) of a cephalosporin combined with 1/4 or 1/2 MIC of a glycopeptide. In the presence of 1/2 SBC of a cephalosporin, vancomycin or teicoplanin MICs decreased an average of 2.0- to 6.6- or 1.6- to 5.5-fold, respectively. With 8 μg/mL cephalosporin, the decline of glycopeptide MICs was most obvious in the presence of cefmetazole. In conclusion, cephalosporin-glycopeptide combinations at clinically achievable concentrations can exhibit in vitro synergistic antibacterial activity against clinical MRSA isolates. Such combinations require more clinical data to support their application for use in human MRSA infections.

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Molecular characteristics and virulence factors in methicillin-susceptible, resistant, and heterogeneous vancomycin-intermediate Staphylococcus aureus from central-southern China

Cited by 51 publications

References 30 publications

Prevalence and Characterization of Oxacillin Susceptible mecA-Positive Clinical Isolates of Staphylococcus aureus Causing Bovine Mastitis in India

Prevalence and Characterization of Oxacillin Susceptible mecA-Positive Clinical Isolates of Staphylococcus aureus Causing Bovine Mastitis in India

Staphylococcus aureus pore-forming toxins: The interface of pathogen and host complexity

Cephalosporin-Glycopeptide Combinations for Use against Clinical Methicillin-Resistant Staphylococcus aureus Isolates: Enhanced In vitro Antibacterial Activity

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