mecA-positive oxacillin phenotypically susceptible Staphylococcus aureus (OS-MRSA) is increasingly reported worldwide. This bacterium poses a therapeutic threat, as it can be misidentified as an ...oxacillin-susceptible organism by phenotypic methods that are routinely used in the majority of clinical microbiology laboratories. Herein, we report the first case of fatal sepsis in a 43-year-old female patient caused by an OS-MRSA SCCmec type IVa/ST1/CC1 in a tertiary hospital in southern Brazil, which highlights the difficulties involved in diagnosing this bacterium. Blood cultures and phenotypic susceptibility tests on admission yielded a penicillin-resistant S. aureus. Although vancomycin therapy was initiated, this antibacterial was replaced by oxacillin, based on the susceptibility result. However, the clinical conditions of the patient deteriorated rapidly evolving to fatal septic shock. Clinical microbiology laboratories should consider the use of additional tests to accurately distinguish between various antimicrobial phenotypes of S. aureus.
Staphylococcus aureus is a major cause of a wide diversity of infections in humans, and the expression of Panton-Valentine Leukocidin (PVL) has been associated with severe clinical syndromes.
The ...present study aimed to investigate the prevalence of PVL-encoding genes in S. aureus isolated from clinical samples of inpatients with invasive infections in a teaching hospital in Southern Brazil. Furthermore, phenotypic and genotypic characteristics of bacterial isolates were analyzed.
A total of 98 S. aureus isolates recovered from different body sites were characterized according to their antimicrobial susceptibility profile, methicillin-resistance and SCCmec typing, genetic relatedness and occurrence of virulence-encoding genes, such as icaA, lukS-PV/lukF-PV, and tst.
Sixty-eight (69.4%) isolates were classified as methicillin-resistant, and among them, four (5.9%) did not harbor the mecA gene. The mecA-harboring methicillin-resistant S. aureus (MRSA) isolates were grouped into SCCmec types I (6.3%), II (64.1%), III (6.3%), IV (15.6%), V (4.7%), and VI (1.6%). One isolate (1.6%) was classified as non-typeable (NT). Seventy isolates (71.4%) were classified as multidrug-resistant. The overall prevalence of virulence-encoding genes was as follows: icaA, 99.0%; tst, 27.5%; and lukS-PV/lukF-PV, 50.0%. The presence of tst gene was significantly higher (p < 0.001) in methicillin-susceptible S. aureus (MSSA) compared to MRSA isolates.
The present study reports a high prevalence of multidrug-resistant S. aureus harboring lukS-PV/lukF-PV and tst genes in invasive infections. The continuous monitoring of the antimicrobial susceptibility profile and virulence of S. aureus is an important measure for the control of infections caused by this bacterium.
Methicillin-resistant Staphylococcus aureus (MRSA) is one of the leading causes of human infections worldwide, with major dominant lineage circulating in particular geographical regions. The ...Brazilian Epidemic Clone (BEC, SCCmec III, ST 239) has been predominant in most Brazilian hospitals. Here, we report the prevalence of MRSA SCCmec type II exhibiting different STs, most of them belonging to CC5 in a tertiary hospital in Southern Brazil.
Background. Staphylococcus aureus can asymptomatically colonize the human anterior nares and skin, and nasal colonization by this bacterium represents a potential risk for development of invasive ...infections. The aim of this study was to determine the prevalence of S. aureus nasal carriage among healthcare workers and students attending a university hospital and to characterize the isolates phenotypically and molecularly. Methods. A cross-sectional study was performed with 324 volunteers. Cultures from nasal samples were obtained and S. aureus isolates were characterized according to their antimicrobial susceptibility profile and four virulence factors-encoding genes. MRSA isolates were characterized regarding their oxacillin/cefoxitin susceptibility, SCCmec, and REP-PCR types. Potential risks for S. aureus and MRSA carriage were analyzed. Results. Of 324 nasal samples, 42.9% were identified as S. aureus, of which 28.8% were MRSA. S. aureus carriers were significantly higher in males and students (OR = 2.898, 95%CI 1.553–5.410); however, no variables were associated with MRSA carriage. All isolates were susceptible to vancomycin and the highest rate of resistance was observed for penicillin (90.6%). All isolates harbored the coa gene, and 97.8%, the icaA gene; 15.8% and 6.5% were positive for tst and lukS-PV/lukF-PV genes, respectively. Among MRSA isolates, 45% carried the mecA gene but were phenotypically susceptible to oxacillin/cefoxitin; two harbored the tst and none had lukS-PV/lukF-PV genes. All MRSAs were distributed into six SCCmec types and type I (62.5%) was the most frequent. REP-PCR typing identified four main clusters among MRSA isolates. Conclusion. High prevalence of healthcare workers and students were identified as nasal carriers of S. aureus exhibiting different antimicrobial resistance profiles, including mecA-positive oxacillin-susceptible S. aureus (OS-MRSA) and the presence of virulence-encoding genes. Both cohorts may represent potential sources for the emergence of a successful S. aureus strain highly adapted to the hospital environment.
Justificativa e Objetivo: Infecções da corrente sanguínea por Staphylococcus aureus constituem uma das principais causas de morbidade e mortalidade em todo mundo. O tratamento de infecções por S. ...aureus é complicado pela elevada prevalência de resistência a antimicrobianos. Compreender a epidemiologia e os padrões de resistência deste microrganismo é um ponto crítico para a prescrição empírica adequada de antimicrobianos. Desta maneira, este estudo teve por objetivo avaliar a evolução de resistência antimicrobiana de S. aureus num período de quinze anos. Metodologia: Foram analisados os testes de sensibilidade aos antimicrobianos de 720 S. aureus isolados de hemoculturas de um hospital terciário do sul do Brasil. Os dados foram obtidos do Sistema de Informação AGTA Healthcare, módulo LABHOS®. Resultados: A frequência média de S. aureus resistentes a meticilina foi de 43,74%. Com exceção de penicilina, ocorreu variação significativa da resistência para todos os antimicrobianos no período avaliado (< 0,001). Ciprofloxacina, Eritromicina e Clindamicina apresentaram os maiores índices de resistência com tendência de aumento. Surpreendentemente, Gentamicina e Sulfametoxazol-Trimetoprim apresentaram queda significativa nos percentuais de resistência. Analisando-se vancomicina do ano 2011 a 2015 pode-se evidenciar um aumento das concentrações inibitórias mínimas. Conclusão: Embora a resistência a antimicrobianos tenha aumentado nos quinze anos para a maioria dos antimicrobianos, para Sulfametoxazol-Trimetoprim e Gentamicina ocorreu redução significativa, indicando uma possível alteração clonal. Este estudo evidenciou, ainda, a emergência do fenótipo S. aureus intermediário a vancomicina.
Staphylococcus haemolyticus is one of the most frequently coagulasenegative staphylococci isolated from healthcare-associated infections, mainly those related to implanted medical devices.
This study ...aimed to determine the antimicrobial susceptibility profile and biofilm forming capacity of S. haemolyticus isolated from bloodstream infections.
A total of 40 S. haemolyticus isolates were characterized according to their genetic relatedness by repetitive element sequence based-PCR (REP-PCR), antimicrobial susceptibility profile, SCCmec typing, ability to form biofilm on abiotic surface and occurrence of putative genes related to biofilm formation.
One S. haemolyticus was susceptible to all antimicrobials. The other isolates (n=39) were resistant to cefoxitin; and among them 34 (87.2%) harbored the mecA gene into the SCCmec type I (5.9%), type III (29.4%), type IV (5.9%) and type V (20.6%); and 38.2% isolates were designated as NT. Apart from cefoxitin, 94.9% of the isolates were resistant to at least four antimicrobial classes, and 32.5% displayed minimal inhibitory concentration (MIC) values higher than 4.0 μg/mL for vancomycin. All isolates formed biofilm on polystyrene surface and were classified as strong biofilm-producers, except for one isolate. All isolates were negative for icaA gene, and the prevalence of the other genes was as follows: atl, 100%; fbp, 92.5%; aap, 90.0%; and bap, 20.0%.
This study reports a high prevalence of methicillin-resistant S. haemolyticus displaying decreased susceptibility to vancomycin with the ability to form strong biofilms on abiotic surface. The results support the importance of controlling the adequate use of antimicrobials for the treatment of staphylococcal infections.
A onicomicose é uma doença caracterizada pela infecção de fungos em uma ou mais unhas, infecção essa que pode ser causada por fungos dermatófitos ou não, que necessita de diagnóstico precoce e ...atendimento qualificado para que haja um resultado efetivo em seu tratamento. Entender quais são as principais características dessa patologia, assim como, as técnicas de identificação do microrganismo na região ungueal, de forma com que os profissionais da área da saúde, quando estiverem frente ao tratamento desta, saibam qual técnica de pesquisa laboratorial melhor se enquadra e a que menos apresenta chance de um resultado falso negativo, é o foco deste estudo. O foco é diminuir as doenças co-relacionadas com esta infecção, como o contagio de outras pessoas circundantes a este paciente potencialmente contaminado, e a utilização de métodos tópicos para tratamento da doença.
Staphylococcus aureus é um microrganismo versátil que causa grande diversidade de infecções, acomentendo tecidos superficiais ou ocasionando síndromes invasivas, como pneumonias e bacteremias. Esse ...trabalho teve como objetivos analisar a resistência, virulência e as relações epidemiológicas e genéticas de Staphylococcus aures,oriundos de sangue e secreção traqueal, em um hospital terciário do sul do Brasil. A identificação dos microganismo, bem como a determinação do perfil de resistência aos antimicrobianos, foi realizada por metodologia manual, de acordo com o CLSI, 2018, e automatizada utilizando ossistemasVitek®2 (bioMeriéux-USA), Phoenix® (Becton, Dickinson) e Microscan® (Siemens- Califórnia). A concentração inibitória mímina de vancomicina foi deterinada por fitas de e-test®(bioMeriéux-USA). O DNA total dos isolados, extraido por protocolo enzimático, foi utilizado para pesquisa dos genes mecA, icaA, pvl e tsst, além da análise dos Complexos Clonais e Sequence Typing. Foi realizado, para um isolado, sequenciamento genômico total utilizando a plataforma Miseq® (Illumina). Foram avaliados 720 isolados de S. aureus provenientes de bacteremia entre os anos de 2001-2015. Observou-se que, para os antimicrobianos ciprofloxacina, eritromicina, oxacilina e clindamicina houve aumento no percentual de isolados resistentes, com tendência de elevação.Enquanto para gentamicina, rifampicina, tetraciclina e sulfametoxazol-trimetoprima houve queda nos percentuais. O periodo de avaliação para vancomicina foi de cinco anos (2011-2015), mostrando elevação nas concentrações inibitórias mínimas. Para os anos de 2015-2016, 105 isolados de S. aureus oriundos de sangue e secreção traqueal foram avaliados. Verificou-se que 81,9 % dos isolados foram positivos para o gene mecA. Na amplificação dos tipos SCCmec o tipo II foi detectado como prevalente, sendo positivo em 61,67%, 23,33% pertenciam ao tipo IV, 13,33% foram do tipo I e apenas uma amostra, 1,67%, continha o tipo III. Verificou-se ainda, a presença de 30 Sequence Type e 18 Complexos Clonais, sendo que os mais frequentes foram ST63 (12,16%), ST6 (8,1%) e ST5, 306 e 835 (6,8%). Quanto aos CC os mais prevalentes foram os CC5 (50%), CC7 e CC445 (6,8%). Ao analisar os fatores de virulência percebeu-se que 87,8% das amostras continham o operon icaA, 16,2% apresentaram o operon pvl e 14,9 o tsst. Conclui-se que a maioria dos isolados apresentava, como fator de virulência, o operon icaA, eram portadores do gene mecA e pertenciam ao SCCmec tipo II, ST63 e CC5. Quanto ao perfil de sensibilidade aos antimicrobinos houve tendência de elevação no perfil de resistência para oxacilina, ciprofloxacina, clindamicina e eritromicina e tendência e queda para gentamicina, rifampicina e sulfametaxol-trimetoprima. Quanto a vancomicina houve tendência de elevação na concentração inibitórima mínina. Avaliando o sequênciamento do genoma foi encontrado mutação no gene mecA, bem como o gene femXAB.
Staphylococcus aureus is a versatile microorganism that causes a wide range of infections, involving superficial tissues or causing invasive syndromes, such as pneumonia and bacteremia. The objective of this study was to analyze the resistance, virulence and epidemiological and genetic relationships of Staphylococcus aureus isolated from blood and tracheal secretion in a tertiary hospital in southern Brazil. The identification of the microorganisms, as well as the determination of the antimicrobial resistance profile, was performed by manual methodology, according to the CLSI, 2018, and automated using Vitek®2 (bioMeriéux-USA), Phoenix® (Becton, Dickinson) and Microscan® ( Siemens-California). The minimum inhibitory concentration of vancomycin was determined by e-test® tapes (bioMeriéux-USA). The total DNA of the isolates, extracted by enzymatic protocol, was used to investigate the mecA, icaA, pvl and tsst genes, in addition to the Clonal Complex and Sequence Typing analysis. We performed, for one isolate, total genomic sequencing using the Miseq® (Illumina) platform. A total of 720 isolates of S. aureus from bacteremia were evaluated between 2001-2015. It was observed that, for the antimicrobials ciprofloxacin, erythromycin, oxacillin and clindamycin, there was an increase in the percentage of resistant isolates with a tendency to increase. While for gentamicin, rifampicin, tetracycline and sulfamethoxazole-trimethoprim, there was a decrease in percentages. The vancomycin evaluation period was from five years (2011-2015), showing an increase in the minimum inhibitory concentrations. For the years 2015-2016, 105 S. aureusisolated from blood and tracheal secretion were evaluated. It was found that 81.9% of the isolates were positive for the mecA gene. In the amplification of SCCmec types, type II was detected as prevalent, 61.67% followed by type IV, 23.33% and type I, 13.33%. Only one isolate had type III, 1.67%. The presence of 30 Sequence Type and 18 Clonal Complexes was also observed, with ST63 (12.16%), ST6 (8.1%) and ST5, 306 and 835 (6.8%) being the most frequent. The most prevalent CCs were CC5 (50%), CC7 and CC445 (6.8%). When analyzing the virulence factors, it was observed that 87.8% of the samples contained the icaA operon, 16.2% had pvl operons and 14.9 tsst. It was concluded that most of the isolates presented, as a virulence factor, the icaA operon, were carriers of the mecA gene and belonged to SCCmec type II, ST63 and CC5. As for the antimicrobial susceptibility profile, there was a tendency to increase the resistance profile for oxacillin, ciprofloxacin, clindamycin and erythromycin and tendency and fall for gentamicin, rifampicin and sulfamethoxol-trimethoprim. As for vancomycin, there was a tendency to increase the minimum inhibitory concentration. Evaluating the genome sequencing was found mutation in the mecA gene as well as the femXAB genes.
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