Phenotypic and Molecular Characteristics of Community-Associated Staphylococcus aureus Infection in Neonates

Zhao

Emerging Microbes & Infections

et al. 2022

Methicillin-resistant Staphylococcus aureus (MRSA) ST8 strains have spread worldwide, causing outbreaks in various regions. However, this clone has only been sporadically reported in China. Consequently, detailed information regarding the phylogeny and potential virulence of S. aureus ST8 strains in China remains unknown. In this study, we characterized six ST8 strains collected from three tertiary hospitals in China, including three MRSA (MR50, MR526, and MR254) and three MSSA (H78, H849 and H863). Whole genome sequencing and phylogenetic analysis showed that the six strains formed two separate clusters, including two (MR50 and MR526) and four (MR254, H78, H849 and H863) isolates, respectively. Among them, MR50 and MR526 harboured spa t008, SCC mec IVa, arginine catabolic mobile element, and were phylogenetically close to the epidemic USA300 strains, while other four strains belonged to spa t9101 and formed a unique branch. MR254 carried a novel hybrid SCC mec element (namely SCC mec 254). Same as the USA300 prototype strain LAC, the China S. aureus ST8 strains produced weak biofilms except MR254. Among them, MR254 had significantly stronger haemolysis ability and higher α-toxin levels than others, while MR526 showed comparable haemolysis and α-toxin production levels as USA300-LAC. In mouse skin abscess model, MR254 showed particularly strong invasions, accompanied by necrosis, while MR526 exhibited similar infection levels as USA300-LAC. These data suggested that the China MRSA ST8 isolates (e.g. MR254 and MR526) were highly virulent, displaying higher or similar virulence potential as the epidemic USA300 strain. Active surveillance should be enacted to closely monitor the further spread of these hyper-virulent MRSA strains in China.

Section: Introductionmentioning

confidence: 55%

Section: Introductionmentioning

confidence: 99%

Identification of methicillin-resistant Staphylococcus aureus ST8 isolates in China with potential high virulence

Zhao

Emerging Microbes & Infections

et al. 2022

Experimental Dermatology

“…phenotype and infection outcome. [116][117][118] There are numerous SA CCs identified worldwide; as discussed above, however, the main studies on CCs in AD have been on CC1 and CC30. We will therefore focus on further describing these two clonal lineages and potential relationships with virulence in AD.…”

Section: Ta B L E 2 Clonal Complexes and Important Findings In Atopic Dermatitismentioning

confidence: 99%

“…virulence genes, notably including SEB and Panton-Valentine leucocidin (PVL). 116,124,125 PVL-positive SA has high virulence and is associated with recurrent skin and soft tissue infections (SSTIs) and necrotizing pneumonia; it has also been isolated in high prevalence from the nares and lesional skin in paediatric AD patients. 126,127 SEB, as discussed above, has not been associated with higher severity scores in AD patients.…”

Section: Ta B L E 2 Clonal Complexes and Important Findings In Atopic Dermatitismentioning

confidence: 99%

Updated understanding of Staphylococcus aureus in atopic dermatitis: From virulence factors to commensals and clonal complexes

Hwang

Thompson

Jaros

et al. 2021

Atopic dermatitis (AD) is an inflammatory dermatosis with a pathogenesis believed to be due to a combination of genetic, immunologic and environmental factors that affects up to 5% of adults and 20% of children worldwide. 1,2 Common genetic factors include polymorphisms in the filaggrin structural protein, interleukin (IL)-4 receptor and vitamin D receptor. [3][4][5] AD is driven by multiple immune pathways, most commonly with activation of Th2 and Th22 T-cell subsets. 6 Crosstalk between commensals and the host immune system modulates adaptive and innate immune responses in AD. 7 Staphylococcus aureus (SA) in AD lesions and surrounding normal skin was first noted by Leyden et al. in the 1970s; since then, the understanding of its role in AD has drastically evolved. 8,9 SA is a well-established exacerbator of AD; it is frequently isolated from the skin of AD patients and increased SA density is found during flares. 10 A meta-analysis in 2016 reported a pooled prevalence of SA colonization among AD patients of 70% in lesional skin, 39% in non-lesional skin and 62% in the nose. 11 More recently, Kong et al 12 found that AD treatments and flares were closely associated with shifts in the cutaneous microbial diversity. While current evidence has established that SA proliferates during flares and plays a role in the cycle of epidermal breakdown and inflammation, a true causal relationship has not been established. Herein, we will summarize the

Ann Clin Microbiol Antimicrob

“…Of note, the rate of resistance to metronidazole, as an effective antibiotic against anaerobic bacteria, is about 1%, but some reference laboratories have reported a resistance rate of up to 7.5% [ 14 – 16 ]. Moreover, the number of multidrug-resistant B. fragilis isolates has increased over the last decade [ 17 – 19 ]. Improper and excessive use of antibiotics without a doctor’s supervision are the reason for promotes bacterial resistance [ 20 ].…”

Section: Introductionmentioning

confidence: 99%

Antibiotic resistance pattern of Bacteroides fragilis isolated from clinical and colorectal specimens

Jasemi

Emaneini

Ahmadinejad

et al. 2021

Background Bacteroides fragilis is a part of the normal gastrointestinal flora, but it is also the most common anaerobic bacteria causing the infection. It is highly resistant to antibiotics and contains abundant antibiotic resistance mechanisms. Methods The antibiotic resistance pattern of 78 isolates of B. fragilis (22 strains from clinical samples and 56 strains from the colorectal tissue) was investigated using agar dilution method. The gene encoding Bacteroides fargilis toxin bft, and antibiotic resistance genes were targeted by PCR assay. Results The highest rate of resistance was observed for penicillin G (100%) followed by tetracycline (74.4%), clindamycin (41%) and cefoxitin (38.5%). Only a single isolate showed resistance to imipenem which contained cfiA and IS1186 genes. All isolates were susceptible to metronidazole. Accordingly, tetQ (87.2%), cepA (73.1%) and ermF (64.1%) were the most abundant antibiotic-resistant genes identified in this study. MIC values for penicillin, cefoxitin and clindamycin were significantly different among isolates with the cepA, cfxA and ermF in compare with those lacking such genes. In addition, 22.7 and 17.8% of clinical and GIT isolates had the bft gene, respectively. Conclusions The finding of this study shows that metronidazole is highly in vitro active agent against all of B. fragilis isolates and remain the first-line antimicrobial for empirical therapy.