Quorum sensing is a cell-cell signaling mechanism based on cell density and that involves the pro... more Quorum sensing is a cell-cell signaling mechanism based on cell density and that involves the production of hormone-like molecules called autoinducers (AI). One of the most studied AIs has been termed AI-2, and its biosynthesis requires the enzyme encoded by luxS. We have previously described for the first time that Bacteroides species can produce molecules with AI-2 activity. In this study, we focus on the detection of luxS and its activity as the AI-2 synthase in Bacteroides species. The strains Bacteroides fragilis B3b and Bacteroides vulgatus ATCC 8482 were selected based on a positive phenotype for AI-2 production and the presence of a putative luxS in the genome, respectively. In order to identify the luxS gene, cloning and heterologous expression strategies were utilized. We demonstrate that both strains contain functional luxS orthologs that can complement AI-2 production in Escherichia coli.
Brazilian Journal of Pharmaceutical Sciences, 2014
ABSTRACT Staphylococcus epidermidis resistente à meticilina (MRSE) e Staphylococcus haemolyticus ... more ABSTRACT Staphylococcus epidermidis resistente à meticilina (MRSE) e Staphylococcus haemolyticus resistente à meticilina (MRSHa) são importantes estafilococos coagulase negativa. São frequentemente isolados em bacteremia humana, principalmente devido à capacidade de formar biofilmes nas superfícies de dispositivos médicos introduzidos no organismo. A papaína é mistura complexa de enzimas proteolíticas e peroxidases extraídas do látex de Carica papaya, reconhecida por acelerar os processos de cura de feridas. Este estudo teve como objetivo avaliar a capacidade dos MRSE e MRSHa em produzir biofilmes e analisar a capacidade da papaína em inibir a formação de biofilme ou desintegrar biofilmes já formados por essas bactérias. Observou-se que a papaína tem capacidade de reduzir a formação de biofilme por MRSE (p < 0,06) e MRSHa (p = 0,0005). Além disso, a papaína foi capaz de desintegrar biofilme maduro formado por MRSE (p = 0,014). Nenhuma atividade antibacteriana da papaína foi observada para qualquer das duas espécies de bactérias testadas. A papaína mostrou-se produto potencial para reduzir biofilme.
Pelger-Huët anomaly is an inherited condition characterized by hyposegmentation of the neutrophil... more Pelger-Huët anomaly is an inherited condition characterized by hyposegmentation of the neutrophil nucleus and excessive chromatin clumping. Acquired Pelger-Huët, also known as pseudo-Pelger-Huët, has been described in several clinical conditions including transplant recipients who received immunosuppressive drugs. The incidence of pseudo-Pelger-Huët in kidney transplant patients, characterized as neutrophil dysplasia, was observed in 9 of 170 patients (5.3%) at the São Francisco Hospital de Assis, Belo Horizonte, Brazil. Awareness of possible circulating neutrophil alterations in transplant patients is important for laboratory professionals who should report these findings of cell changes. It should be highlighted that the poor segmentation and the chromatin hypercondensation observed initially in pseudo-Pelger-Huët patients can be suggestive of early-stage neutrophils. Only a combination of laboratory and clinical data will facilitate a better understanding of this anomaly and its correct follow-up and management.
Revista da Sociedade Brasileira de Medicina Tropical, 2015
Acquired production of metallo-β-lactamases is an important mechanism of resistance in Pseudomona... more Acquired production of metallo-β-lactamases is an important mechanism of resistance in Pseudomonas aeruginosa. The objective of this study was to investigate the production of metallo-β-lactamase and the genetic diversity among ceftazidime-resistant P. aeruginosa isolates from State of Sergipe, Brazil. Metallo-β-lactamase was investigated using the disk approximation test and polymerase chain reaction (PCR). Genetic diversity was evaluated by pulsed-field gel electrophoresis (PFGE). A total of 48 (51.6%) isolates were resistant to ceftazidime. Six (12.2%) of these were positive for metallo-β-lactamase production. Only two (4.1%) of the ceftazidime-resistant isolates carried the bla SPM-1 gene. Production of metallo-β-lactamases was not the main mechanism of resistance to ceftazidime and carbapenems among P. aeruginosa strains in Sergipe, Brazil.
The aim of this study was to evaluate the sporicidal activity of hospital disinfectants against s... more The aim of this study was to evaluate the sporicidal activity of hospital disinfectants against spores of two Brazilian Clostridium difficile ribotypes and the BI/NAP1/027. Our results showed that CloroRio(®) and Cidex Opa(®) were the most efficient agents for eliminating spores of C difficile.
Streptococcus agalactiae is known to be the major cause of neonatal infections and also causes co... more Streptococcus agalactiae is known to be the major cause of neonatal infections and also causes complications during pregnancy. One hundred and six strains of Streptococcus agalactiae recovered from clinical specimens of newborns (n = 18) and pregnant women (n = 88) were submitted to antimicrobial susceptibility testing and investigation of genetic determinants of macrolide resistance, capsular type, and virulence factors. Genetic diversity was evaluated by pulsed-field gel electrophoresis (PFGE) analysis. Strains were susceptible to ceftriaxone, levofloxacin, penicillin G, and vancomycin and resistant to tetracycline (85.8%) and erythromycin (4.7%). Erythromycin-resistant strains presented iMLSB phenotype, harbored the ermA gene, and were closely related by PFGE. Both bac and bca genes were found in low frequencies. PFGE analysis yielded 11 DNA restriction profiles among 35 selected isolates. The major clonal group, designated as A, was composed predominantly of strains belonging to capsular type Ia. Clonal group B was composed predominantly of strains with capsular type V, including all erythromycin-resistant isolates. Although low levels of erythromycin resistance have been observed, this is a fact of concern because this phenotype also confers resistance to clindamycin, an alternative agent for intrapartum prophylaxis. Despite the diversity of capsular types, Ia and V were among the most common and were significantly associated with distinct clonal groups. In a few cases, different capsular types were clustered into a single clonal group, which may be related to capsular switching.
Quorum sensing is a cell-cell signaling mechanism based on cell density and that involves the pro... more Quorum sensing is a cell-cell signaling mechanism based on cell density and that involves the production of hormone-like molecules called autoinducers (AI). One of the most studied AIs has been termed AI-2, and its biosynthesis requires the enzyme encoded by luxS. We have previously described for the first time that Bacteroides species can produce molecules with AI-2 activity. In this study, we focus on the detection of luxS and its activity as the AI-2 synthase in Bacteroides species. The strains Bacteroides fragilis B3b and Bacteroides vulgatus ATCC 8482 were selected based on a positive phenotype for AI-2 production and the presence of a putative luxS in the genome, respectively. In order to identify the luxS gene, cloning and heterologous expression strategies were utilized. We demonstrate that both strains contain functional luxS orthologs that can complement AI-2 production in Escherichia coli.
Brazilian Journal of Pharmaceutical Sciences, 2014
ABSTRACT Staphylococcus epidermidis resistente à meticilina (MRSE) e Staphylococcus haemolyticus ... more ABSTRACT Staphylococcus epidermidis resistente à meticilina (MRSE) e Staphylococcus haemolyticus resistente à meticilina (MRSHa) são importantes estafilococos coagulase negativa. São frequentemente isolados em bacteremia humana, principalmente devido à capacidade de formar biofilmes nas superfícies de dispositivos médicos introduzidos no organismo. A papaína é mistura complexa de enzimas proteolíticas e peroxidases extraídas do látex de Carica papaya, reconhecida por acelerar os processos de cura de feridas. Este estudo teve como objetivo avaliar a capacidade dos MRSE e MRSHa em produzir biofilmes e analisar a capacidade da papaína em inibir a formação de biofilme ou desintegrar biofilmes já formados por essas bactérias. Observou-se que a papaína tem capacidade de reduzir a formação de biofilme por MRSE (p < 0,06) e MRSHa (p = 0,0005). Além disso, a papaína foi capaz de desintegrar biofilme maduro formado por MRSE (p = 0,014). Nenhuma atividade antibacteriana da papaína foi observada para qualquer das duas espécies de bactérias testadas. A papaína mostrou-se produto potencial para reduzir biofilme.
Pelger-Huët anomaly is an inherited condition characterized by hyposegmentation of the neutrophil... more Pelger-Huët anomaly is an inherited condition characterized by hyposegmentation of the neutrophil nucleus and excessive chromatin clumping. Acquired Pelger-Huët, also known as pseudo-Pelger-Huët, has been described in several clinical conditions including transplant recipients who received immunosuppressive drugs. The incidence of pseudo-Pelger-Huët in kidney transplant patients, characterized as neutrophil dysplasia, was observed in 9 of 170 patients (5.3%) at the São Francisco Hospital de Assis, Belo Horizonte, Brazil. Awareness of possible circulating neutrophil alterations in transplant patients is important for laboratory professionals who should report these findings of cell changes. It should be highlighted that the poor segmentation and the chromatin hypercondensation observed initially in pseudo-Pelger-Huët patients can be suggestive of early-stage neutrophils. Only a combination of laboratory and clinical data will facilitate a better understanding of this anomaly and its correct follow-up and management.
Revista da Sociedade Brasileira de Medicina Tropical, 2015
Acquired production of metallo-β-lactamases is an important mechanism of resistance in Pseudomona... more Acquired production of metallo-β-lactamases is an important mechanism of resistance in Pseudomonas aeruginosa. The objective of this study was to investigate the production of metallo-β-lactamase and the genetic diversity among ceftazidime-resistant P. aeruginosa isolates from State of Sergipe, Brazil. Metallo-β-lactamase was investigated using the disk approximation test and polymerase chain reaction (PCR). Genetic diversity was evaluated by pulsed-field gel electrophoresis (PFGE). A total of 48 (51.6%) isolates were resistant to ceftazidime. Six (12.2%) of these were positive for metallo-β-lactamase production. Only two (4.1%) of the ceftazidime-resistant isolates carried the bla SPM-1 gene. Production of metallo-β-lactamases was not the main mechanism of resistance to ceftazidime and carbapenems among P. aeruginosa strains in Sergipe, Brazil.
The aim of this study was to evaluate the sporicidal activity of hospital disinfectants against s... more The aim of this study was to evaluate the sporicidal activity of hospital disinfectants against spores of two Brazilian Clostridium difficile ribotypes and the BI/NAP1/027. Our results showed that CloroRio(®) and Cidex Opa(®) were the most efficient agents for eliminating spores of C difficile.
Streptococcus agalactiae is known to be the major cause of neonatal infections and also causes co... more Streptococcus agalactiae is known to be the major cause of neonatal infections and also causes complications during pregnancy. One hundred and six strains of Streptococcus agalactiae recovered from clinical specimens of newborns (n = 18) and pregnant women (n = 88) were submitted to antimicrobial susceptibility testing and investigation of genetic determinants of macrolide resistance, capsular type, and virulence factors. Genetic diversity was evaluated by pulsed-field gel electrophoresis (PFGE) analysis. Strains were susceptible to ceftriaxone, levofloxacin, penicillin G, and vancomycin and resistant to tetracycline (85.8%) and erythromycin (4.7%). Erythromycin-resistant strains presented iMLSB phenotype, harbored the ermA gene, and were closely related by PFGE. Both bac and bca genes were found in low frequencies. PFGE analysis yielded 11 DNA restriction profiles among 35 selected isolates. The major clonal group, designated as A, was composed predominantly of strains belonging to capsular type Ia. Clonal group B was composed predominantly of strains with capsular type V, including all erythromycin-resistant isolates. Although low levels of erythromycin resistance have been observed, this is a fact of concern because this phenotype also confers resistance to clindamycin, an alternative agent for intrapartum prophylaxis. Despite the diversity of capsular types, Ia and V were among the most common and were significantly associated with distinct clonal groups. In a few cases, different capsular types were clustered into a single clonal group, which may be related to capsular switching.
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