Persistence of a multidrug-resistant worldwide-disseminated methicillin-resistant Staphylococcus epidermidis clone harbouring the cfr linezolid resistance gene in a French hospital with evidence of interspecies transfer to several Staphylococcus aureus lineages.

BACKGROUND: Resistance to linezolid has become a worldwide concern since it is one of the last-resort antibiotics to treat multidrug-resistant staphylococcal and enterococcal infections. OBJECTIVES: We investigated staphylococcal infections caused by 16 cfr-positive linezolid-resistant Staphylococcus epidermidis and Staphylococcus aureus isolates in a French university hospital from 2015 to 2018. METHODS: Antimicrobial susceptibility of isolates was tested by broth microdilution and gradient strips. Genetic determinants of linezolid resistance (including cfr gene and 23S rRNA mutations) were assessed by PCR and WGS; the latter was also used to characterize the cfr-carrying plasmids in S. epidermidis and S. aureus, and to explore the clonal relationship of isolates. RESULTS: All linezolid-resistant staphylococcal isolates harboured the same cfr-carrying plasmid, sharing 99% identity with the previously described pSA737. The three S. aureus isolates belonged to different STs (ST8, ST72, ST2416); the 13 methicillin-resistant S. epidermidis (MRSE) belonged to ST2 and harboured both cfr and mutations in genes encoding 23S rRNA and ribosomal proteins. Phylogenetic analysis grouped the MRSE isolates into two clusters, one of which (n = 12 isolates) belonged to the recently reported multidrug-resistant worldwide-disseminated S. epidermidis lineages. CONCLUSIONS: The results presented herein highlight the persistence and efficient spread of a cfr-carrying plasmid in a hospital related both to the dissemination of a multidrug-resistant S. epidermidis clone and the in vivo interspecies transfer of cfr between S. epidermidis and S. aureus. The emergence of linezolid-resistant strains should be closely monitored, and the mechanisms involved systematically explored in order to limit the spread of plasmid-mediated resistance.

PGAM1 and TP53 mRNA levels in canine mammary carcinomas - Short communication.

TP53 and PGAM1 genes play a key role in glycolysis which is an essential metabolic pathway of cancer cells for obtaining energy. The purpose of this work was to evaluate PGAM1 and TP53 mRNA expressions in canine mammary carcinomas (CMC) and to correlate them with animal data and tumour histological features. None of the nine samples analysed revealed PGAM1 DNA sequence variations. PGAM1 and TP53 RNA expressions from 21 CMC were analysed using a one-step reverse transcription-PCR kit and its platform system. Most CMC samples had low levels of PGAM1 mRNA (71.5%) and normal expression of TP53 mRNA (95.2%). Our results suggest a different feature of the Warburg effect on canine mammary cancer cells compared to human cells.

The multifaceted resources and microevolution of the successful human and animal pathogen methicillin-resistant Staphylococcus aureus

Methicillin-resistant Staphylococcus aureus (MRSA) is one of the most important bacterial pathogens based on its incidence and the severity of its associated infections. In addition, severe MRSA infections can occur in hospitalised patients or healthy individuals from the community. Studies have shown the infiltration of MRSA isolates of community origin into hospitals and variants of hospital-associated MRSA have caused infections in the community. These rapid epidemiological changes represent a challenge for the molecular characterisation of such bacteria as a hospital or community-acquired pathogen. To efficiently control the spread of MRSA, it is important to promptly detect the mecA gene, which is the determinant of methicillin resistance, using a polymerase chain reaction-based test or other rapidly and accurate methods that detect the mecA product penicillin-binding protein (PBP)2a or PBP2’. The recent emergence of MRSA isolates that harbour a mecA allotype, i.e., the mecC gene, infecting animals and humans has raised an additional and significant issue regarding MRSA laboratory detection. Antimicrobial drugs for MRSA therapy are becoming depleted and vancomycin is still the main choice in many cases. In this review, we present an overview of MRSA infections in community and healthcare settings with focus on recent changes in the global epidemiology, with special reference to the MRSA picture in Brazil.

Prevalência de Staphylococcus aureus resistentes à meticilina (MRSA) produtores de leite humano ordenhado e seu crescimento em colostro humano / Prevalence of enterotoxigenic Staphylococcus aureus resistant to meticilin (MRSA) in milked samples of human milk and their growth in human colostrum

Foram coletados e analisadas 500 amostras de leite humano ordenhado, oriundas de cinco cidades brasileiras (100 de cada), visando detectar cepas de staphylococcus aureus resistentes à meticilina (MRSA) produtoras de enterotoxinas. Nestas amostras foram encontradas 57 cepas de mMRSA, sendo confirmada a presença do gene mecA, responsável pela resitência, por meio de sonda molecular específica. Posteriormente, 40 das 57 cepas isoladas, foram selecionadas de modo a conter todas as cepas representantes de cada regiäo, com exceçäo da que apresentava a maioria, da qual foram selecionadas aleatoriamente 10 cepas para completar as 40 a serem analisadas. As cepas foram submetidas a pesquisa de quatro enterotoxinas por meio do Kit SET-RPLA (oxoid). Dentre estas, foram encontradas duas produtoras de enteroxina B, com as quais foram feitas curvas de crescimento em colostro humano e em " Trypticase Soy Broth", Tendo por fim avaliar o impacto dos fatores de defesa do colostro sobre o desenvolvimento e produçäo de toxinas pelos microorganismos em questäo. Para tal, foram inoculadas 5,0 x 10 elevado ao quadrado UFC/ml, que representava aproximadamente a média das contagens das cepas S. aureus nas amostras que continham as cepas resitentes à meticilina. Após cinco horas de incubaçäo a 37 graus celcius as populaçöes eram superiores a 4,9 x 10 elevado a quatro UFC/ml e apresentavam liberaçäo de enterotoxinas no meio de cultura e no colostro. Nossos resultados ressaltam a importância dos cuidados higiênicos-sanitários e das técnicas apropriadas de preservaçäo do leite humano ordenhado, para evitar a proliferaçäo do S. aureus e a conseqüente produçäo de enterotoxinas no produto, que por näo poderem ser removidas nem destruídas pelos procedimentos normais, levariam risco de vida a seus receptores

Estocagem de bacteriófilos de Streptococcus pyrogenes na presença de substâncias crioprotetoras / Storage of bacteriophages from Streptococcus pyogenes in the presence of cryoprotective substances

Foi estudada a infectividade de bacteriófagos temperados de Streptococcus pyogenes após estocagens dos mesmos nas temperaturas de -20 a 4-C, durante 35 dias, na presença de diferentes substâncias crioprotetoras comumente utilizadas na conservaçäo de suspensäo virais. Os fagos foram inativados rapidamente quando estocados juntamente com os lisados bacterianos, mesmo na presença dos crioprotetores. Maior estabilidade foi obtida após purificaçäo parcial através de lavagens com tampäo fosfato de sódio (100.000g/1h) e posterior estocagem na presença dos crioprotetores. Verificamos que os bacteriófagos tiveram a sua infectividade preservada quando estocados a 4-C na presença de sacrose, dimetilsulfóxido, acetado de amônio de dextrana durante 35 dias

Lisogenia e resistência à tetraciclina em estreptococos do grupo A / Lysogeny and resistance to tetracycline in streptococco group A

Lisogenia em amostras de estreptococos do grupo A foi examinada. Verificou-se que entre as lisogênicas a resistência a tetraciclina era mais comum