Introduction: Infections caused by methicillin-resistant Staphylococcus aureus (MRSA) have become common in hospitals and the community environment, and this wide resistance has limited patient treatment. Clindamycin (CL) represents an important alternative therapy for infections caused by S. aureus. Antimicrobial susceptibility testing using standard methods may not detect inducible CL resistance. This study was performed to detect the phenotypes of resistance to macrolides-lincosamides-streptogramin B (MLS B ) antibiotics, including CL, in clinical samples of S. aureus from patients at a tertiary hospital in Santa Maria, State of Rio Grande do Sul, Brazil. Methods: One hundred and forty clinical isolates were submitted to the disk diffusion induction test (D-test) with an erythromycin (ER) disk positioned at a distance of 20mm from a CL disk. The results were interpreted according to the recommendations of the Clinical and Laboratory Standards Institute (CLSI). Results: In this study, 29 (20.7%) of the 140 S. aureus samples were resistant to methicillin (MRSA), and 111 (79.3%) were susceptible to methicillin (MSSA). The constitutive resistance phenotype (cMLS B ) was observed in 20 (14.3%) MRSA samples and in 5 (3.6%) MSSA samples, whereas the inducible resistance phenotype (iMLS B ) was observed in 3 (2.1%) MRSA samples and in 8 (5.8%) MSSA samples. Conclusions: The D-test is essential for detecting the iMLS B phenotype because the early identifi cation of this phenotype allows clinicians to choose an appropriate treatment for patients. Furthermore, this test is simple, easy to perform and inexpensive.

Este artigo está licenciado sob forma de uma licença Creative Commons Atribuição 4.0 Internacional, que permite uso irrestrito, distribuição e reprodução em qualquer meio, desde que a publicação original seja corretamente citada. ABSTRACT Aims:To evaluate the prevalence of bacteria in urine cultures of pregnant women seen at the outpatient clinic of the Department of Obstetrics at the University Hospital of Santa Maria, Brazil, and to determine the antibiotic sensitivity profile of these bacteria. Methods:The reports issued by the Laboratory of Clinical Analysis of the University Hospital of Santa Maria were retrospectively analyzed. All positive urine cultures of pregnant women seen at the Department of Obstetrics from January to December 2014 were included in the study. The tests for the identification of bacterial isolates and their sensitivity profiles were assessed by an automated system. Results: A total of 423 positive urine cultures were detected in the pregnant women. Gram-negative Escherichia coli was the most prevalent microorganism (46.50%). Gram-positive Staphylococcus saprophyticus was the second most prevalent bacterium (6.2%). Candida spp. was isolated from 94 (21.8%) urine samples. Nitrofurantoin and amoxicillin/clavulanic acid showed the lowest antimicrobial resistance against E. coli (91.33% and 90.77%, respectively). Ampicillin had the highest sensitivity among prevalent Gram-positive bacteria. Conclusions:The sensitivity profile found in this study allows us to suggest nitrofurantoin and/or amoxicillin/clavulanic acid for the treatment of urinary tract infection caused by Gram-negative bacteria during pregnancy. Given the prevalence rates detected in this study, these antimicrobials can be initiated empirically before the urine culture results are known, in the cases of symptomatic urinary tract infection. This study underscores the importance of urine culture in the prenatal period and in the third trimester because of the different microorganisms identified and the different sensitivity to the antimicrobials tested.

The repositioning of approved drugs is atopic of interest for the academy and the pharmaceutical industry. The synergistic combination of these drugs can be successful in the treatment of infections caused by resistant bacteria. This study aimed to assess the in vitro synergistic antibacterial activity of sertraline and disulfiram and their interaction with ciprofloxacin and sulfamethoxazole/trimethoprim. We determined the minimum inhibitory concentration, the minimum bactericidal concentration and the fractional inhibitory concentration index. Eighteen bacterial strains were used, being nine American Type Culture Collection reference strains and nine multidrug resistant clinical isolates. Synergy was detected between sertraline and disulfiram against a strain of Staphylococcus aureusATCC 25923 and a clinical isolate of S. aureus. When associated to sulfamethoxazole/trimethoprim and ciprofloxacin, sertraline and disulfiram showed eight synergistic events, which occurred against three different standard strains and two multidrug resistant clinical isolates. When the minimum bactericidal concentration was determined, the bactericidal activity of sertraline was enhanced with disulfiram. Our results suggest that these drugs, widely used to treat depression and chronic alcoholism, have antibacterial potential individually, in association, and combined with antimicrobials, what makes their repositioning a promising therapeutic alternative for the effective treatment of infections caused by multidrug resistant bacteria.

OBJETIVO: O objetivo deste trabalho foi avaliar a prevalência e perfil de resistência dos microrganismos isolados de secreções de pele e tecidos moles. Este tipo de estudo, pelo que é de nosso conhecimento, foi o primeiro realizado neste hospital com período de quatro anos e elevado número de amostras. MÉTODOS: Realizou-se um estudo observacional retrospectivo de culturas de infecções de pele coletadas em hospital escola terciário, no período de janeiro de 2014 a dezembro de 2017. Os testes de identificação dos microrganismos e perfil de sensibilidade foram efetuados por meio de sistemas convencionais e automatizados (Vitek® 2 – bioMérieux). RESULTADOS: No período deste estudo, 675 amostras resultaram positivas, sendo Staphylococcus aureus (118; 17,48%), Pseudomonas aeruginosa (106; 15,70%), Staphylococcus epidermidis (65; 9,63%) e Escherichia coli (60; 8,89%) os microrganismos predominantes. Em relação à Pseudomonas aeruginosa, 53,77% das cepas apresentaram resistência ao imipenem e 44,34% ao meropenem. As opções terapêuticas para o tratamento das infecções causadas por esse microrganismo são limitadas. CONCLUSÕES: O perfil epidemiológico dos agentes envolvidos é similar ao citado na literatura internacional, o que diferencia é o perfil de sensibilidade. Fato que necessita monitoramento é que Pseudomonas aeruginosa ocupou o segundo lugar na etiologia e apresentou significativa resistência frente aos carbapenêmicos.

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