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The emergence and increasing prevalence of livestock-associated methicillinresistant Staphylococcus aureus (LA-MRSA) are a global concern. To investigate the prevalence and characteristics of sequence type 398 (ST398) MRSA in pig ears, 102 pig's ears were collected from 102 animals shipped from 51 farms at an abattoir. Eight ST398 MRSA isolates were isolated from the ears of eight pigs shipped from seven farms. Of the eight ST398 isolates, seven had the staphylococcal cassette chromosome mec (SCCmec) type IVd and these were obtained from seven pigs shipped from six farms. Single nucleotide polymorphisms ranging from 13 to 26 were observed in the core-genome regions in the seven SCCmec type IVd isolates. We believe that this is the first report on the isolation of ST398 MRSA SCCmec type IVd in Japan. [ABSTRACT FROM AUTHOR]

Staphylococcus aureus (S. aureus) is now regarded as a zoonotic agent. Methicillin-susceptible S. aureus (MSSA) ST398 is a livestock-associated bacterium that is most prevalent in China, but there are currently no data available for Shandong. Therefore, the aim of this study was to investigate the epidemiology and characterization of MSSA ST398 from retail pork and bulk tank milk (BTM) in Shandong. A total of 67 S. aureus isolates were collected from retail pork between November 2017 and June 2018. Among the isolates, high antimicrobial resistance rates were observed for penicillin (97.0%), and 92.5% of the isolates were multi-drug resistant (MDR). Eight sequence types (STs) were identified in the retail pork isolates, and the predominant type was ST15 (n=26), which was followed by ST398 (n=14). Staphylococcal protein A gene (spa) typing identified spa types t034 and t1255 in MSSA ST398 from retail pork. Using whole-genome sequencing analysis, we described the phylogeny of 29 MSSA ST398 isolates that were obtained from retail pork (n=14) and BTM (n=15). The phylogenetic tree showed that the MSSA ST398 isolates from different sources had the same lineage. Among the 29 MSSA ST398 isolates, five resistance genes were detected, and all isolates carried DHA-1. Fifteen toxin genes were detected, and all isolates carried eta, hla, and hlb. In conclusion, this study found that a high risk for MSSA ST398 was present in retail pork and BTM. These findings have major implications for how investigations of MSSA ST398 outbreaks should be conducted in the One-Health context.

Staphylococcus aureus (S. aureus) is now regarded as a zoonotic agent. Methicillin-susceptible S. aureus (MSSA) ST398 is a livestock-associated bacterium that is most prevalent in China, but there are currently no data available for Shandong. Therefore, the aim of this study was to investigate the epidemiology and characterization of MSSA ST398 from retail pork and bulk tank milk (BTM) in Shandong. A total of 67 S. aureus isolates were collected from retail pork between November 2017 and June 2018. Among the isolates, high antimicrobial resistance rates were observed for penicillin (97.0%), and 92.5% of the isolates were multi-drug resistant (MDR). Eight sequence types (STs) were identified in the retail pork isolates, and the predominant type was ST15 (n =26), which was followed by ST398 (n =14). Staphylococcal protein A gene (spa) typing identified spa types t034 and t1255 in MSSA ST398 from retail pork. Using whole-genome sequencing analysis, we described the phylogeny of 29 MSSA ST398 isolates that were obtained from retail pork (n =14) and BTM (n =15). The phylogenetic tree showed that the MSSA ST398 isolates from different sources had the same lineage. Among the 29 MSSA ST398 isolates, five resistance genes were detected, and all isolates carried DHA-1. Fifteen toxin genes were detected, and all isolates carried eta , hla , and hlb. In conclusion, this study found that a high risk for MSSA ST398 was present in retail pork and BTM. These findings have major implications for how investigations of MSSA ST398 outbreaks should be conducted in the One-Health context. [ABSTRACT FROM AUTHOR]

Abstract Background Methicillin-resistant Staphylococcus aureus (MRSA) ST398 is a livestock associated-bacterium that is most prevalent in Europe. Human-adapted MRSA ST398 was recently reported from China, but there is no data available yet for Taiwan. Methods To identify S. aureus ST398 isolates, we examined 6413 S. aureus isolates (5632 MRSA and 781 susceptible strains) that were collected in Taiwan between 1995 and 2017. If isolates could not be typed by pulsed-field gel electrophoresis upon Sma I digestion, we performed further characterization and complete genome sequencing. Results We identified 18 ST398 S. aureus isolates from 16 subjects (0.28%), including 6 sensitive and 12 resistant strains. Of these, 14 were colonizing isolates, 3 were clinical (infecting) isolates and one isolate was from a pork specimen. All 3 infecting isolates were MSSA strains identified in 2015 from two children with recurrent otitis media or sinusitis. The other 3 MSSA isolates were identified from workers handling pork (2) or pork meat (1) in 2015. The first 5 MRSA colonizing isolates were identified from residents in two nursing homes in 2012. Six MRSA isolates were identified from residents and foreign employees at a nursing home in 2016 and one MRSA from a foreign worker in 2017. Phylogenetic analysis of genome sequences indicated that all 12 local ST398 MRSA strains cluster together, human-adapted and phylogenetically related to a human MRSA strain identified in China in 2002. Two local MSSA isolates could be linked to isolates from livestock. The toxin profiles were similar for the MRSA and MSSA isolates. Conclusions Our results demonstrate that S. aureus ST398 was present in Taiwan in 2012 and potentially earlier. Although some isolates could be linked to livestock, most ST398 S. aureus isolates identified in Taiwan, particularly MRSA, represent human-adapted strains. Local transmission of human-adapted MRSA ST398 strains has occurred in nursing homes in Taiwan, possibly after import from China. Further surveillance is needed.

Staphylococcus aureus (S. aureus) sequence type 398 (ST398) has aroused great concern for its spread throughout the world. ST398 community-acquired MRSA (CA-MRSA) has been given greater emphasis because of its high virulence and high probability of treatment failure. Herein, A 22-year-old male was admitted to our hospital with a history of fever, chest pain and dyspnea for 2 days. A chest CT scan showed infiltrative and nodular shadows. The sequence type of the isolates from blood culture was ST398, the virulence genes detected was PVL gene (lukS -PV and lukF -PV). Despite resuscitation efforts, he died of multiple organ failure on admission 3rd day. This is the first described case of severe pneumonia and sepsis due to hematogenous spread of scalp furuncles caused by Panton–Valentine leukocidin (PVL) positive community-acquired methicillin-susceptible S. aureus (CA-MSSA) ST398 strains in an immunocompentent adult in mainland China. This report highlight the emergence CA-PVL-MSSA ST398 infection and its association with life-threatening infections. Early decolonization and identification of ST398 is critical. Severe skin and soft tissue infections should be suspected for ST398 PVL-MSSA. [ABSTRACT FROM AUTHOR]

The global increase of community-associated (CA) infections with methicillin-resistant Staphylococcus aureus (MRSA) is a major healthcare problem. Although sequence type (ST) 398 MRSA was first described as a livestock-associated (LA) lineage, human-adapted MRSA (HO-MRSA) ST398 without livestock contact has subsequently been reported from China in our previous study and other later research. The proportion of ST398 HO-MRSA has also remarkably increased in recent years in China. Based on 3878 S. aureus isolates that were collected in a general hospital between 2008 and 2018, we identified 56 ST398 HO-MRSA isolates. The four early appearing isolates of them have been sequenced by whole-genome sequencing (WGS) in our previous study. Here, by usage of WGS on the later-appearing 52 isolates and analyzing the phylogenetic dynamics of the linage, we found that 50 isolates clustered together with the former 4 isolates, making it a main clade out of MSSA clones and other MRSA clones, although ST398 HO-MRSA evolved with multiple origins. Drug resistance and virulence gene analysis based on the WGS data demonstrated that ST398 HO-MRSA main clade exhibited a similar pattern in both parts. Furthermore, they all carried a conserved variant of prophage 3 to guarantee virulence and a short SCCmec type V element of class D to maintain considerable lower methicillin resistance. Further phenotypical research verified that the epidemic HO-MRSA ST398 displayed enhanced biofilm formation ability when keeping high virulence. The dual advantages of virulence and biofilm formation in the HO-MRSA ST398 subtype promote their fitness in the community and even in the healthcare environment, which poses a serious threat in clinical S. aureus infections. Therefore, further surveillance is required to prevent and control the problematic public health impact of HO-MRSA ST398 in the future.

The global increase of community-associated (CA) infections with methicillin-resistant Staphylococcus aureus (MRSA) is a major healthcare problem. Although sequence type (ST) 398 MRSA was first described as a livestock-associated (LA) lineage, human-adapted MRSA (HO-MRSA) ST398 without livestock contact has subsequently been reported from China in our previous study and other later research. The proportion of ST398 HO-MRSA has also remarkably increased in recent years in China. Based on 3878 S. aureus isolates that were collected in a general hospital between 2008 and 2018, we identified 56 ST398 HO-MRSA isolates. The four early appearing isolates of them have been sequenced by whole-genome sequencing (WGS) in our previous study. Here, by usage of WGS on the later-appearing 52 isolates and analyzing the phylogenetic dynamics of the linage, we found that 50 isolates clustered together with the former 4 isolates, making it a main clade out of MSSA clones and other MRSA clones, although ST398 HO-MRSA evolved with multiple origins. Drug resistance and virulence gene analysis based on the WGS data demonstrated that ST398 HO-MRSA main clade exhibited a similar pattern in both parts. Furthermore, they all carried a conserved variant of prophage 3 to guarantee virulence and a short SCC mec type V element of class D to maintain considerable lower methicillin resistance. Further phenotypical research verified that the epidemic HO-MRSA ST398 displayed enhanced biofilm formation ability when keeping high virulence. The dual advantages of virulence and biofilm formation in the HO-MRSA ST398 subtype promote their fitness in the community and even in the healthcare environment, which poses a serious threat in clinical S. aureus infections. Therefore, further surveillance is required to prevent and control the problematic public health impact of HO-MRSA ST398 in the future. [ABSTRACT FROM AUTHOR]

Monitoring the prevalence of livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA) in pigs could be useful for managing transmission risk to humans. To optimize sampling for LA-MRSA monitoring, we compared the sensitivity of MRSA isolation from skin swabs taken behind the ear and nasal swabs collected from 276 pigs and investigated the prevalence of MRSA in their carcasses. MRSA was isolated from 40 behind the ear skin swabs (14.5%), which was statistically higher than the number isolated from nasal swabs (23 samples, 8.3%). MRSA prevalence in the carcasses was 0.4%. All MRSA isolates were sequence type 398 lineage. Sampling of both the skin behind the ear and nasal mucosa in a pig is recommended to investigate the prevalence of LA-MRSA in pigs. [ABSTRACT FROM AUTHOR]

Background: Methicillin-resistant Staphylococcus aureus (MRSA) ST398 is a livestock associated-bacterium that is most prevalent in Europe. Human-adapted MRSA ST398 was recently reported from China, but there is no data available yet for Taiwan. Methods: To identify S. aureus ST398 isolates, we examined 6413 S. aureus isolates (5632 MRSA and 781 susceptible strains) that were collected in Taiwan between 1995 and 2017. If isolates could not be typed by pulsed-field gel electrophoresis upon Sma I digestion, we performed further characterization and complete genome sequencing. Results: We identified 18 ST398 S. aureus isolates from 16 subjects (0.28%), including 6 sensitive and 12 resistant strains. Of these, 14 were colonizing isolates, 3 were clinical (infecting) isolates and one isolate was from a pork specimen. All 3 infecting isolates were MSSA strains identified in 2015 from two children with recurrent otitis media or sinusitis. The other 3 MSSA isolates were identified from workers handling pork (2) or pork meat (1) in 2015. The first 5 MRSA colonizing isolates were identified from residents in two nursing homes in 2012. Six MRSA isolates were identified from residents and foreign employees at a nursing home in 2016 and one MRSA from a foreign worker in 2017. Phylogenetic analysis of genome sequences indicated that all 12 local ST398 MRSA strains cluster together, human-adapted and phylogenetically related to a human MRSA strain identified in China in 2002. Two local MSSA isolates could be linked to isolates from livestock. The toxin profiles were similar for the MRSA and MSSA isolates. Conclusions: Our results demonstrate that S. aureus ST398 was present in Taiwan in 2012 and potentially earlier. Although some isolates could be linked to livestock, most ST398 S. aureus isolates identified in Taiwan, particularly MRSA, represent human-adapted strains. Local transmission of human-adapted MRSA ST398 strains has occurred in nursing homes in Taiwan, possibly after import from China. Further surveillance is needed. [ABSTRACT FROM AUTHOR]

Methicillin-resistant Staphylococcus aureus sequence type 398 (ST398 MRSA) was identified in Dutch pigs and pig farmers. ST398 methicillin-susceptible S. aureus circulates among humans at low frequency (0.2%) but was isolated in 3 human cases of bacteremia (2.1%; p = 0.026). Although its natural host is probably porcine, ST398 MRSA likely causes infections in humans.

Abstract: Staphylococcus aureus clonal complex 398 is a livestock-associated pathogen that poses a worldwide threat because of its ability to colonize and infect both humans and animals. We used high-resolution whole-genome microarrays, prophage profiling, immune evasion cluster characterization and whole-genome sequencing to investigate the roles of prophages in the emerging human-adapted subpopulation of CC398 that has been associated with invasive infections in humans living in animal-free environments. We characterized one phage and two prophages specifically harbored by CC398 isolates belonging to the emerging subpopulation. We introduced the phage into permissive prophage-free isolates. We investigated the effects of lysogeny on the host ability to resist further phage infection and transformation, to acquire the capacity to invade human cells, and to express virulence factors encoded by prophages. We report evidence of a defective ϕMR11-like helper prophage, named StauST398-5pro, specifically associated with the emerging non-LA CC398 subpopulation. StauST398-5pro confers substantial protection against horizontal genetic transfer to its host. It interacts with a human-associated β-converting prophage encoding immune-modulating proteins such that virulence genes are expressed during stress situations. Our findings provide insight into the role of phages in the expression of virulence and in the spread of genetic information among new host-adapted S. aureus isolates. We demonstrate that functional prophage elements can condition host specificity and confer new virulence traits on emerging intra-species clones of bacteria. [Copyright &y& Elsevier]

The emergence and increasing prevalence of livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA) are a global concern. To investigate the prevalence and characteristics of sequence type 398 (ST398) MRSA in pig ears, 102 pig's ears were collected from 102 animals shipped from 51 farms at an abattoir. Eight ST398 MRSA isolates were isolated from the ears of eight pigs shipped from seven farms. Of the eight ST398 isolates, seven had the staphylococcal cassette chromosome mec (SCCmec) type IVd and these were obtained from seven pigs shipped from six farms. Single nucleotide polymorphisms ranging from 13 to 26 were observed in the core-genome regions in the seven SCCmec type IVd isolates. We believe that this is the first report on the isolation of ST398 MRSA SCCmec type IVd in Japan.

Monitoring the prevalence of livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA) in pigs could be useful for managing transmission risk to humans. To optimize sampling for LA-MRSA monitoring, we compared the sensitivity of MRSA isolation from skin swabs taken behind the ear and nasal swabs collected from 276 pigs and investigated the prevalence of MRSA in their carcasses. MRSA was isolated from 40 behind the ear skin swabs (14.5%), which was statistically higher than the number isolated from nasal swabs (23 samples, 8.3%). MRSA prevalence in the carcasses was 0.4%. All MRSA isolates were sequence type 398 lineage. Sampling of both the skin behind the ear and nasal mucosa in a pig is recommended to investigate the prevalence of LA-MRSA in pigs.