Characterization of the virulence, agr typing and antimicrobial resistance profile of Staphylococcus aureus strains isolated from food handlers in Brazil

Abstract Staphylococcus aureus is one of the main pathogens associated with foodborne outbreaks in Brazil and food handlers can carry toxigenic and resistant S. aureus strains. The aims of this study were to verify the frequency of virulence genes, to identify the agr groups and to determine the antimicrobial resistance profile of S. aureus strains isolated from food handlers of pilot kitchens located in São Paulo, Brazil. A total of 74 strains of the Staphylococcus genus were detected and 50% were identified as of the species S. aureus. The enterotoxin genes detection, tst and luk-PV detection, agr typing, mecA detection, ccr complex detection and SCCmec typing were performed using PCR. The antimicrobial resistance testing was performed by the disk diffusion method. The enterotoxin genes were identified in 36 S. aureus, including sea (83.8%). The tst gene was detected in 18.92% of the strains and the luk-PV was detected in only one isolate. Agr typing classified 58.3% of the strains as type I. Seven (18.92%) strains were classified as MRSA and the ccr2 complex was detected in six of these isolates. The SCCmec typing characterized strains as type II, III, IV and V. Moreover, there were also a greater number of resistant strains to penicillin (83.78%) and clarithromycin (67.57%). In conclusion, the study revealed a significant prevalence of S. aureus, and the presence of different virulence genes and a worrying resistance profile in S. aureus strains isolated from food handlers in this country.

Main aspects and prophylactic measures of COVID-19 in Brazil / Principais aspectos e medidas profiláticas da COVID-19 no Brasil

From the first case of COVID-19 in Brazil, the country became the third in the world in the raking of cases and deaths. Despite the measures implemented by the government, the number of infected and killed by COVID-19 continues to increase and the country faces several other problems that include social and political aspects, making it difficult to contain the pandemic. The present study addressed the general characteristics of SARS-CoV-2, pointed out the main socio-epidemiological aspects in Brazil and the treatment of COVID 19. A literature review was carried out to search for articles in PubMed, Scielo and Google Scholar databases. Patients with COVID-19 may be asymptomatic, but among symptomatic patients, the severity of the disease is related to age and pre-existing medical conditions. The lungs are the organs most affected by the virus and, for this reason, respiratory manifestations such as cough, shortness of breath, sputum production, sore throat and nasal congestion are the symptoms most associated with COVID-19. The transmission of SARSCoV-2 between humans occurs mainly through respiratory droplets, but they can also occur through contact with contaminated surfaces. Vaccine tests were carried out approved by the World Health Organization (WHO). Brazil stands out in second world position, with four approved vaccines: Pfizer-BioNTech, Oxford-AstraZeneca, CoronaVac (Sinovac), Janssen/Covishield.

A partir do primeiro caso de COVID-19 no Brasil, o país se tornou o terceiro no mundo em números de casos e de óbitos. Apesar das medidas implantadas pelo governo, o número de infectados e de óbitos por COVID-19 continua aumentando e o país enfrenta vários outros problemas que inclui aspectos sociais e políticos, dificultando as medidas de contenção da pandemia. O presente estudo visou abordar as características gerais do SARS-Cov-2, bem como apontar os principais aspectos socioepidemiológico no Brasil, e tratamento da COVID 19. Foi realizada uma revisão de literatura para busca de artigos em Bases de dados PubMed, Scielo e Google Scholar até 06 de outubro de 2020. Os pacientes com COVID-19 podem ser assintomáticos, porém entre os sintomáticos a gravidade da doença está relacionada à idade e a condições médicas pré-existentes. Os pulmões são os órgãos mais afetados pelo vírus e por isso as manifestações respiratórias como tosse, falta de ar, produção de escarro, dor de garganta e congestão nasal são os sintomas mais associados à COVID-19 A transmissão do SARS-COV-2 entre os humanos ocorre principalmente por meio de gotículas respiratórias, mas também podem ocorrer por meio do contato com superfícies contaminadas. Testes de vacinas foram realizados aprovados pela Organização Mundial da Saúde (OMS). O Brasil se destaca em segunda posição mundial, com cinco vacinas aprovadas, Pfizer-BioNTech, Oxford-AstraZeneca, /CoronaVac (Sinovac), Janssen/Covishield.

Enterotoxin genes, multidrug resistance, and molecular typing of Staphylococcus spp. isolated from organic bovine milk / Genes de enterotoxinas, multirresistência a antimicrobianos e caracterização molecular de espécies de Staphylococcus spp. isoladas de leite bovino orgânico

The multidrug resistant and the emergence of methicillin-resistant staphylococci isolated from animals, food, and humans are public health concern. These microorganisms produce different toxins related to food poisoning in humans. This study aimed to characterize Staphylococcus spp. isolated from two organic milk farms in Brazil. A total of 259 milk samples were collected, from which 58 (22.4%) Staphylococcus spp. were isolated. The highest sensibility to ceftiofur and sulfamethoxazole/trimethoprim was observed in 96.6% of Staphylococcus spp., and whereas 89% were resistant to penicillin G. The mecA gene was detected in 13.8% of the isolates. SEA and SEC were the most common enterotoxins detected. PFGE revealed genetic heterogeneity from S. intermedius and S. warneri analyzed, while S. aureus presented similar profiles among isolates from the two studied herds. To the best of our knowledge, the current study describes for the first time presence of enterotoxins, mecA gene, and genetic diversity of staphylococci isolated from organic dairy farms in Brazil.(AU)

A emergência de estafilococos multirresistentes e resistentes à meticilina, isolados de animais, alimentos e humanos é uma preocupação em saúde pública. Esses micro-organismos produzem diferentes toxinas relacionadas à intoxicação alimentar em humanos. Este estudo caracterizou Staphylococcus spp. isolados em duas fazendas orgânicas no Brasil. Foram coletadas 259 amostras de leite em duas propriedades leiteiras orgânicas, nas quais 58 (22,4%) estirpes de Staphylococcus spp. foram isoladas. A maior sensibilidade dos isolados foi observada para ceftiofur e sulfametoxazol/trimetoprim em 96,6%. Em contraste, acima de 89% de resistência dos estafilicocos foi encontrada para penicilina G. O gene mecA foi identificado em 13,8% dos isolados. SEA e SEC foram as enterotoxinas mais comumente detectadas. PFGE revelou heterogeneidade genética entre S. intermedius e S. warneri, enquanto S. aureus demonstraram perfis semelhantes entre isolados dos dois rebanhos estudados. Relata-se pela primeira vez no Brasil a detecção de enterotoxinas, o gene mecA e diversidade genética em estafilococos isolados de vacas em produção orgânica.(AU)

Clonal profile, virulence and resistance of Staphylococcus aureus isolated from sheep milk

The objective of this study was to characterize the clonal profile, virulence factors and antimicrobial resistance, particularly oxacillin resistance, of Staphylococcus aureus isolated from sheep milk. Milk samples were collected from all teats for the California Mastitis Test (CMT), somatic cell count, identification of S. aureus, investigation in these strains of genes encoding toxins (sea, seb, sec, sed, tst), biofilm (icaA, icaC, icaD, bap), leukocidin (luk-PV) oxacillin resistance by mecA gene detection and susceptibility testing (12 antibiotics). Messenger RNA expression was evaluated by RT-PCR in isolates carrying toxin and biofilm genes. Biofilm formation was also evaluated phenotypically by adherence to polystyrene plates. The clonal profile of S. aureus was investigated by pulsed-field gel electrophoresis. A total of 473 milk samples were collected from 242 animals on three farms and 20 S. aureus strains were isolated and none carried the mecA gene. The two sec gene-positive isolates and the isolates carrying the tst and luk-PV genes were positive by RT-PCR. Staphylococcus aureus isolated from the three flocks studied showed high susceptibility to the drugs tested and none was biofilm producer, indicating that biofilm formation was not a virulence factor causing infection by these strains. The typing of 17 S. aureus isolates revealed the presence of a common clone on the three farms studied, and the presence and expression of the sec and tst genes in one strain of this clone suggest the possible acquisition of virulence genes by this clone, a fact that is important for animal health and food hygiene.

Reduced susceptibility to vancomycin and biofilm formation in methicillin-resistant Staphylococcus epidermidis isolated from blood cultures

This study aimed to correlate the presence of ica genes, biofilm formation and antimicrobial resistance in 107 strains of Staphylococcus epidermidis isolated from blood cultures. The isolates were analysed to determine their methicillin resistance, staphylococcal cassette chromosome mec (SCCmec) type, ica genes and biofilm formation and the vancomycin minimum inhibitory concentration (MIC) was measured for isolates and subpopulations growing on vancomycin screen agar. The mecA gene was detected in 81.3% of the S. epidermidis isolated and 48.2% carried SCCmec type III. The complete icaADBC operon was observed in 38.3% of the isolates; of these, 58.5% produced a biofilm. Furthermore, 47.7% of the isolates grew on vancomycin screen agar, with an increase in the MIC in 75.9% of the isolates. Determination of the MIC of subpopulations revealed that 64.7% had an MIC ≥ 4 μg mL-1, including 15.7% with an MIC of 8 μg mL-1 and 2% with an MIC of 16 μg mL-1. The presence of the icaADBC operon, biofilm production and reduced susceptibility to vancomycin were associated with methicillin resistance. This study reveals a high level of methicillin resistance, biofilm formation and reduced susceptibility to vancomycin in subpopulations of S. epidermidis. These findings may explain the selection of multidrug-resistant isolates in hospital settings and the consequent failure of antimicrobial treatment.