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Katia Regina Netto Dos Santos - One of the best experts on this subject based on the ideXlab platform.
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Sphygmomanometers and thermometers as potential fomites of Staphylococcus Haemolyticus: biofilm formation in the presence of antibiotics
Memorias do Instituto Oswaldo Cruz, 2017Co-Authors: Bruna Pinto Ribeiro Sued, Katia Regina Netto Dos Santos, Yuri Vieira Faria, Paula Marcele Afonso Pereira, Vanessa Batista Binatti, Juliana Nunes Ramos, Sergio Henrique Seabra, Raphael Hirata Junior, Verônica Viana Vieira, Ana Luíza Mattos-guaraldiAbstract:BACKGROUND The association between Staphylococcus Haemolyticus and severe nosocomial infections is increasing. However, the extent to which fomites contribute to the dissemination of this pathogen through patients and hospital wards remains unknown. OBJECTIVES In the present study, sphygmomanometers and thermometers were evaluated as potential fomites of oxacillin-resistant S. Haemolyticus (ORSH). The influence of oxacillin and vancomycin on biofilm formation by ORSH strains isolated from fomites was also investigated. METHODS The presence of ORSH on swabs taken from fomite surfaces in a Brazilian hospital was assessed using standard microbiological procedures. Antibiotic susceptibility profiles were determined by the disk diffusion method, and clonal distribution was assessed in pulsed-field gel electrophoresis (PFGE) assays. Minimum inhibitory concentrations (MICs) of oxacillin and vancomycin were evaluated via the broth microdilution method. Polymerase chain reaction (PCR) assays were performed to detect the mecA and icaAD genes. ORSH strains grown in media containing 1/4 MIC of vancomycin or oxacillin were investigated for slime production and biofilm formation on glass, polystyrene and polyurethane catheter surfaces. FINDINGS ORSH strains comprising five distinct PFGE types were isolated from sphygmomanometers (n = 5) and a thermometer (n = 1) used in intensive care units and surgical wards. ORSH strains isolated from fomites showed susceptibility to only linezolid and vancomycin and were characterised as multi-drug resistant (MDR). Slime production, biofilm formation and the survival of sessile bacteria differed and were independent of the presence of the icaAD and mecA genes, PFGE type and subtype. Vancomycin and oxacillin did not inhibit biofilm formation by vancomycin-susceptible ORSH strains on abiotic surfaces, including on the catheter surface. Enhanced biofilm formation was observed in some situations. Moreover, a sub-lethal dose of vancomycin induced biofilm formation by an ORSH strain on polystyrene. MAIN CONCLUSIONS Sphygmomanometers and thermometers are fomites for the transmission of ORSH. A sub-lethal dose of vancomycin may favor biofilm formation by ORSH on fomites and catheter surfaces.
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Linezolid-resistant Staphylococcus Haemolyticus and Staphylococcus hominis: single and double mutations at the domain V of 23S rRNA among isolates from a Rio de Janeiro hospital
Diagnostic microbiology and infectious disease, 2014Co-Authors: Raiane Cardoso Chamon, Natalia Lopes Pontes Iorio, Fernanda Sampaio Cavalcante, Cristiane Roberta Dos Santos Teodoro, Ana Paula De Oliveira, Fernanda Maia, Katia Regina Netto Dos SantosAbstract:In this work, the molecular and phenotypic antimicrobial resistance and clonal diversity of 10 linezolid-resistant Staphylococcus spp. isolates were investigated. The 7 Staphylococcus Haemolyticus isolates presented Staphylococcal cassete chromosome mec (SCCmec) V and belonged to the same pulsed-field gel electrophoresis pulsotype. Their MICs for oxacillin, vancomycin, and linezolid were ≥ 256 μg/mL, 1-4 μg/mL, and 8-16 μg/mL, respectively. The 3 S. hominis presented MIC values 32 to >256 μg/mL, 2-4 μg/mL, and 12-24 μg/mL, and all carried the nontypeable SCCmec (ccr1 + mecA class) and belonged to 2 different genotypes. The cfr gene was not found, but the mutation G2603T was detected in S. Haemolyticus and C2190T and G2603T in Staphylococcus hominis in 23S rRNA. This study demonstrates the spread of a linezolid-resistant S. Haemolyticus genotype and, for the first time, describes the mutation C2190T among S. hominis isolates with a double mutation in Brazil.
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Staphylococcus aureus Staphylococcus epidermidis and Staphylococcus Haemolyticus methicillin resistant isolates are detected directly in blood cultures by multiplex pcr
Microbiological Research, 2010Co-Authors: Eliezer M Pereira, Natalia Lopes Pontes Iorio, Ricardo Pinto Schuenck, Karoline L Malvar, Pricilla D M De Matos, A N Olendzki, Walter M R Oelemann, Katia Regina Netto Dos SantosAbstract:In this study, we standardized and evaluated a multiplex-PCR methodology using specific primers to identify Staphylococcus aureus, Staphylococcus epidermidis and Staphylococcus Haemolyticus and their methicillin-resistance directly from blood cultures. Staphylococci clinical isolates (149) and control strains (16) previously identified by conventional methods were used to establish the multiplex PCR protocol. Subsequently, this methodology was evaluated using a fast and cheap DNA extraction protocol from 25 staphylococci positive blood cultures. A wash step of the pellet with 0.1% bovine serum albumin (BSA) solution was performed to reduce PCR inhibitors. Amplicons of 154bp (mecA gene), 271bp (S. Haemolyticus mvaA gene) and 108 and 124bp (S. aureus and S. epidermidis species-specific fragments, respectively) were observed. Reliable results were obtained for 100% of the evaluated strains, suggesting that this new multiplex-PCR combined with an appropriate DNA-extraction method could be useful in the laboratory for fast and accurate identification of three staphylococci species and simultaneously their methicillin resistance directly in blood cultures.
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heterogeneous resistance to vancomycin in Staphylococcus epidermidis Staphylococcus Haemolyticus and Staphylococcus warneri clinical strains characterisation of glycopeptide susceptibility profiles and cell wall thickening
International Journal of Antimicrobial Agents, 2006Co-Authors: Ana Paula Ferreira Nunes, Lucia M Teixeira, Natalia Lopes Pontes Iorio, Carla Callegario Reis Bastos, L S Fonseca, Thais Soutopadron, Katia Regina Netto Dos SantosAbstract:Abstract The population analysis profile (PAP) method as well as analysis of autolytic activity and cellular ultrastructure by transmission electron microscopy (TEM) were used to characterise Staphylococcus epidermidis , Staphylococcus Haemolyticus and Staphylococcus warneri clinical strains with reduced susceptibility to glycopeptides. All strains showed heterogeneous profiles to vancomycin and teicoplanin by the PAP method. Subpopulations that grew in the presence of high concentrations of each drug were selected from the PAP as derivative strains. Their glycopeptide minimal inhibitory concentrations (MICs) were determined and subsequently all parental and derivative strains were grown in one-half of the MIC of vancomycin or teicoplanin. An increase in cell wall thickness of all derivative strains was seen by TEM, with statistically significant values ( P
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heterogeneous resistance to vancomycin in Staphylococcus epidermidis Staphylococcus Haemolyticus and Staphylococcus warneri clinical strains characterisation of glycopeptide susceptibility profiles and cell wall thickening
International Journal of Antimicrobial Agents, 2006Co-Authors: Ana Paula Ferreira Nunes, Lucia M Teixeira, Natalia Lopes Pontes Iorio, Carla Callegario Reis Bastos, L S Fonseca, Thais Soutopadron, Katia Regina Netto Dos SantosAbstract:The population analysis profile (PAP) method as well as analysis of autolytic activity and cellular ultrastructure by transmission electron microscopy (TEM) were used to characterise Staphylococcus epidermidis, Staphylococcus Haemolyticus and Staphylococcus warneri clinical strains with reduced susceptibility to glycopeptides. All strains showed heterogeneous profiles to vancomycin and teicoplanin by the PAP method. Subpopulations that grew in the presence of high concentrations of each drug were selected from the PAP as derivative strains. Their glycopeptide minimal inhibitory concentrations (MICs) were determined and subsequently all parental and derivative strains were grown in one-half of the MIC of vancomycin or teicoplanin. An increase in cell wall thickness of all derivative strains was seen by TEM, with statistically significant values (P<0.01) compared with their respective parental strains. In general, variable rates of autolysis among the strains were observed. Cell wall thickness is an important factor involved in glycopeptide resistance and, in association with PAP results, confirmed the Brazilian coagulase-negative staphylococci clinical isolates as being heteroresistant to glycopeptides. Detection of these heteroresistant organisms is important in order to achieve more judicious use of vancomycin and teicoplanin in hospitals.
Natalia Lopes Pontes Iorio - One of the best experts on this subject based on the ideXlab platform.
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Linezolid-resistant Staphylococcus Haemolyticus and Staphylococcus hominis: single and double mutations at the domain V of 23S rRNA among isolates from a Rio de Janeiro hospital
Diagnostic microbiology and infectious disease, 2014Co-Authors: Raiane Cardoso Chamon, Natalia Lopes Pontes Iorio, Fernanda Sampaio Cavalcante, Cristiane Roberta Dos Santos Teodoro, Ana Paula De Oliveira, Fernanda Maia, Katia Regina Netto Dos SantosAbstract:In this work, the molecular and phenotypic antimicrobial resistance and clonal diversity of 10 linezolid-resistant Staphylococcus spp. isolates were investigated. The 7 Staphylococcus Haemolyticus isolates presented Staphylococcal cassete chromosome mec (SCCmec) V and belonged to the same pulsed-field gel electrophoresis pulsotype. Their MICs for oxacillin, vancomycin, and linezolid were ≥ 256 μg/mL, 1-4 μg/mL, and 8-16 μg/mL, respectively. The 3 S. hominis presented MIC values 32 to >256 μg/mL, 2-4 μg/mL, and 12-24 μg/mL, and all carried the nontypeable SCCmec (ccr1 + mecA class) and belonged to 2 different genotypes. The cfr gene was not found, but the mutation G2603T was detected in S. Haemolyticus and C2190T and G2603T in Staphylococcus hominis in 23S rRNA. This study demonstrates the spread of a linezolid-resistant S. Haemolyticus genotype and, for the first time, describes the mutation C2190T among S. hominis isolates with a double mutation in Brazil.
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Staphylococcus aureus Staphylococcus epidermidis and Staphylococcus Haemolyticus methicillin resistant isolates are detected directly in blood cultures by multiplex pcr
Microbiological Research, 2010Co-Authors: Eliezer M Pereira, Natalia Lopes Pontes Iorio, Ricardo Pinto Schuenck, Karoline L Malvar, Pricilla D M De Matos, A N Olendzki, Walter M R Oelemann, Katia Regina Netto Dos SantosAbstract:In this study, we standardized and evaluated a multiplex-PCR methodology using specific primers to identify Staphylococcus aureus, Staphylococcus epidermidis and Staphylococcus Haemolyticus and their methicillin-resistance directly from blood cultures. Staphylococci clinical isolates (149) and control strains (16) previously identified by conventional methods were used to establish the multiplex PCR protocol. Subsequently, this methodology was evaluated using a fast and cheap DNA extraction protocol from 25 staphylococci positive blood cultures. A wash step of the pellet with 0.1% bovine serum albumin (BSA) solution was performed to reduce PCR inhibitors. Amplicons of 154bp (mecA gene), 271bp (S. Haemolyticus mvaA gene) and 108 and 124bp (S. aureus and S. epidermidis species-specific fragments, respectively) were observed. Reliable results were obtained for 100% of the evaluated strains, suggesting that this new multiplex-PCR combined with an appropriate DNA-extraction method could be useful in the laboratory for fast and accurate identification of three staphylococci species and simultaneously their methicillin resistance directly in blood cultures.
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multiplex pcr assay to identify methicillin resistant Staphylococcus Haemolyticus
Fems Immunology and Medical Microbiology, 2008Co-Authors: Ricardo Pinto Schuenck, Natalia Lopes Pontes Iorio, Eliezer M Pereira, Kaitia Dos R N SantosAbstract:Staphylococcus Haemolyticus is the most frequently coagulase-negative Staphylococcus species associated with antimicrobial resistance isolated from nosocomial infections. We developed an accurate and simple multiplex PCR assay to identify methicillin-resistant S. Haemolyticus (MRSH) isolates. We designed species-specific primers of the mvaA gene that encodes a 3-hydroxy-3-methylglutaryl coenzyme A involved in the mevalonate pathway of the microorganism. Simultaneously, mecA gene primers of methicillin resistance were also used. The PCR assay was established using 16 strains of different reference Staphylococcus species and validated with a collection of 147 clinical staphylococcal isolates that were also phenotypically characterized. Reliable results for the detection of MRSH isolates were obtained for 100% of the strains evaluated, showing that this PCR assay can be used for the routine microbiology laboratories. This is the first report using species-specific multiplex PCR to detect a single segment of S. Haemolyticus associated with a segment of mecA gene.
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heterogeneous resistance to vancomycin in Staphylococcus epidermidis Staphylococcus Haemolyticus and Staphylococcus warneri clinical strains characterisation of glycopeptide susceptibility profiles and cell wall thickening
International Journal of Antimicrobial Agents, 2006Co-Authors: Ana Paula Ferreira Nunes, Lucia M Teixeira, Natalia Lopes Pontes Iorio, Carla Callegario Reis Bastos, L S Fonseca, Thais Soutopadron, Katia Regina Netto Dos SantosAbstract:Abstract The population analysis profile (PAP) method as well as analysis of autolytic activity and cellular ultrastructure by transmission electron microscopy (TEM) were used to characterise Staphylococcus epidermidis , Staphylococcus Haemolyticus and Staphylococcus warneri clinical strains with reduced susceptibility to glycopeptides. All strains showed heterogeneous profiles to vancomycin and teicoplanin by the PAP method. Subpopulations that grew in the presence of high concentrations of each drug were selected from the PAP as derivative strains. Their glycopeptide minimal inhibitory concentrations (MICs) were determined and subsequently all parental and derivative strains were grown in one-half of the MIC of vancomycin or teicoplanin. An increase in cell wall thickness of all derivative strains was seen by TEM, with statistically significant values ( P
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heterogeneous resistance to vancomycin in Staphylococcus epidermidis Staphylococcus Haemolyticus and Staphylococcus warneri clinical strains characterisation of glycopeptide susceptibility profiles and cell wall thickening
International Journal of Antimicrobial Agents, 2006Co-Authors: Ana Paula Ferreira Nunes, Lucia M Teixeira, Natalia Lopes Pontes Iorio, Carla Callegario Reis Bastos, L S Fonseca, Thais Soutopadron, Katia Regina Netto Dos SantosAbstract:The population analysis profile (PAP) method as well as analysis of autolytic activity and cellular ultrastructure by transmission electron microscopy (TEM) were used to characterise Staphylococcus epidermidis, Staphylococcus Haemolyticus and Staphylococcus warneri clinical strains with reduced susceptibility to glycopeptides. All strains showed heterogeneous profiles to vancomycin and teicoplanin by the PAP method. Subpopulations that grew in the presence of high concentrations of each drug were selected from the PAP as derivative strains. Their glycopeptide minimal inhibitory concentrations (MICs) were determined and subsequently all parental and derivative strains were grown in one-half of the MIC of vancomycin or teicoplanin. An increase in cell wall thickness of all derivative strains was seen by TEM, with statistically significant values (P<0.01) compared with their respective parental strains. In general, variable rates of autolysis among the strains were observed. Cell wall thickness is an important factor involved in glycopeptide resistance and, in association with PAP results, confirmed the Brazilian coagulase-negative staphylococci clinical isolates as being heteroresistant to glycopeptides. Detection of these heteroresistant organisms is important in order to achieve more judicious use of vancomycin and teicoplanin in hospitals.
Shogo Masuda - One of the best experts on this subject based on the ideXlab platform.
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development of a real time pcr assay for the detection and identification of Staphylococcus capitis Staphylococcus Haemolyticus and Staphylococcus warneri
Journal of Medical Microbiology, 2007Co-Authors: Tadayuki Iwase, Hitomi Shinji, Yoshimitsu Mizunoe, Keiko Seki, Shogo MasudaAbstract:Staphylococcus capitis, Staphylococcus Haemolyticus and Staphylococcus warneri are coagulase-negative staphylococci. Each species has different characteristics, and a difference in pathology is also seen in compromised hosts. Therefore, the development of a species-specific simple detection method for the identification of these staphylococci is important. Here, a species-specific real-time PCR assay is reported that targets the superoxide dismutase A-encoding gene of these bacteria. Primers were designed with a base that was non-complementary with regard to the other bacteria. This base was at the 3′ end of the primer (3′ mismatch primer) and conferred high specificity. These primers were then evaluated using real-time PCR. They reacted only with the target bacterium. In addition, stable quantitative reactions were observed when experiments were performed using genomic DNA extracted from varying numbers of staphylococci cells (101–107 cells). These results indicate that this method is useful for the identification and quantitative analysis of S. capitis, S. Haemolyticus and S. warneri.
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development of a real time pcr assay for the detection and identification of Staphylococcus capitis Staphylococcus Haemolyticus and Staphylococcus warneri
Journal of Medical Microbiology, 2007Co-Authors: Tadayuki Iwase, Hitomi Shinji, Yoshimitsu Mizunoe, Keiko Seki, Shogo MasudaAbstract:Staphylococcus capitis, Staphylococcus Haemolyticus and Staphylococcus warneri are coagulase-negative staphylococci. Each species has different characteristics, and a difference in pathology is also seen in compromised hosts. Therefore, the development of a species-specific simple detection method for the identification of these staphylococci is important. Here, a species-specific real-time PCR assay is reported that targets the superoxide dismutase A-encoding gene of these bacteria. Primers were designed with a base that was non-complementary with regard to the other bacteria. This base was at the 3′ end of the primer (3′ mismatch primer) and conferred high specificity. These primers were then evaluated using real-time PCR. They reacted only with the target bacterium. In addition, stable quantitative reactions were observed when experiments were performed using genomic DNA extracted from varying numbers of staphylococci cells (101–107 cells). These results indicate that this method is useful for the identification and quantitative analysis of S. capitis, S. Haemolyticus and S. warneri.
Hyung Kwoun Kim - One of the best experts on this subject based on the ideXlab platform.
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cell surface display of Staphylococcus Haemolyticus l62 lipase in escherichia coli and its application as a whole cell biocatalyst for biodiesel production
Journal of Molecular Catalysis B-enzymatic, 2013Co-Authors: Soonja Kim, Jae Kwang Song, Hyung Kwoun KimAbstract:Abstract Staphylococcus Haemolyticus L62 (SHL62) lipase was displayed on the cell surface of Escherichia coli using an autotransporter protein of Pseudomonas putida EstAβ8 as an anchoring motif. Localization of the SHL62 lipase on the cell surface of E. coli was confirmed by immunofluorescence microscopy, flow cytometry analysis, Western blot, protease accessibility, and whole-cell enzyme activity assays. SHL62 lipase activity of whole cells reached 168 U/g dry cell weight toward p -nitrophenyl caprylate after being induced by 0.1 mM IPTG for 24 h. The optimum temperature and pH of the displayed SHL62 lipase was 40–45 °C and pH 10, respectively. The displayed SHL62 was stable up to 45 °C, at which it had >80% of maximum activity. The displayed SHL62 lipase showed a preference for medium chain fatty acids of p -nitrophenyl esters. Moreover, the displayed SHL62 lipase was used as a whole cell catalyst to produce biodiesel that was obtained at a yield of nearly 89.4% after a 96 h reaction at 30 °C. These results suggest that the displayed SHL62 lipase on the cell surface of E. coli using an EstAβ8 anchoring motif can be used for biocatalytic applications.
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biodiesel production using cross linked Staphylococcus Haemolyticus lipase immobilized on solid polymeric carriers
Journal of Molecular Catalysis B-enzymatic, 2013Co-Authors: Sang Hyeon Kim, Soonja Kim, Seongsoon Park, Hyung Kwoun KimAbstract:Abstract Various plant oils and animal fats can be used for the production of biodiesel, a renewable and eco-friendly alternative fuel. In this research, transesterification of olive oil and methanol was performed using Staphylococcus Haemolyticus L62 lipase expressed in Escherichia coli cells. L62 lipase was relatively methanol-stable and could produce biodiesel by a one-step methanol-feeding process. This enzyme was immobilized on a poly (methacrylate-co-divinyl benzene) resin by two different methods: hydrophobic adsorption/entrapment (H-L62) and hydrophobic adsorption/entrapment plus covalent cross-linking (HC-L62). Both immobilized enzymes showed quite increased temperature and pH stabilities, whereas they had very similar optimal temperature and pH in comparison with the soluble free enzyme. Soluble L62, H-L62 and HC-L62 lipases could produce biodiesel efficiently from olive oil. Among them, HC-L62 lipase was the most robust enzyme on the basis of multiple reusability. HC-L62 produced biodiesel with various plant oils including palm, olive fomase oils as well as waste cooking oil, suggesting that it can be utilized as a biocatalyst in the biodiesel industry.
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Staphylococcus Haemolyticus lipase biochemical properties substrate specificity and gene cloning
Fems Microbiology Letters, 1999Co-Authors: Hyung Kwoun Kim, Jung Kee Lee, Sun Chul KangAbstract:Lipase of Staphylococcus Haemolyticus L62 was purified from culture supernatant and its molecular mass was estimated to be 45 kDa by SDS-PAGE. Its optimum temperature and pH for the hydrolysis of olive oil was 28°C and pH 8.5, respectively. The enzyme was stable up to 50°C in the presence of Ca2+and over the pH range 5–11. It had high hydrolytic activity against tributyrin, tripropionin, and trimyristin among various triglycerides. The gene encoding the lipase was cloned in Escherichia coli. Sequence analysis showed an open reading frame of 2136 bp, which encodes a preproenzyme of 711 amino acids. The preproenzyme is composed of a signal peptide (60 aa), a pro-peptide (259 aa), and a mature enzyme (392 aa). The mature enzyme has 49–67% amino acid sequence homology with other staphylococcal lipases.
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Staphylococcus Haemolyticus lipase: biochemical properties, substrate specificity and gene cloning
Wiley-Blackwell, 1999Co-Authors: Hyung Kwoun Kim, Jung Kee Lee, Sun Chul KangAbstract:Lipase of Staphylococcus Haemolyticus L62 was purified from culture supernatant and its molecular mass was estimated to be 45 kDa by SDS-PAGE. Its optimum temperature and pH for the hydrolysis of olive oil was 28°C and pH 8.5, respectively. The enzyme was stable up to 50°C in the presence of Ca2+and over the pH range 5-11. It had high hydrolytic activity against tributyrin, tripropionin, and trimyristin among various triglycerides. The gene encoding the lipase was cloned in Escherichia coli. Sequence analysis showed an open reading frame of 2136 bp, which encodes a preproenzyme of 711 amino acids. The preproenzyme is composed of a signal peptide (60 aa), a pro-peptide (259 aa), and a mature enzyme (392 aa). The mature enzyme has 49-67% amino acid sequence homology with other staphylococcal lipases.ope
Ana Paula Ferreira Nunes - One of the best experts on this subject based on the ideXlab platform.
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heterogeneous resistance to vancomycin in Staphylococcus epidermidis Staphylococcus Haemolyticus and Staphylococcus warneri clinical strains characterisation of glycopeptide susceptibility profiles and cell wall thickening
International Journal of Antimicrobial Agents, 2006Co-Authors: Ana Paula Ferreira Nunes, Lucia M Teixeira, Natalia Lopes Pontes Iorio, Carla Callegario Reis Bastos, L S Fonseca, Thais Soutopadron, Katia Regina Netto Dos SantosAbstract:Abstract The population analysis profile (PAP) method as well as analysis of autolytic activity and cellular ultrastructure by transmission electron microscopy (TEM) were used to characterise Staphylococcus epidermidis , Staphylococcus Haemolyticus and Staphylococcus warneri clinical strains with reduced susceptibility to glycopeptides. All strains showed heterogeneous profiles to vancomycin and teicoplanin by the PAP method. Subpopulations that grew in the presence of high concentrations of each drug were selected from the PAP as derivative strains. Their glycopeptide minimal inhibitory concentrations (MICs) were determined and subsequently all parental and derivative strains were grown in one-half of the MIC of vancomycin or teicoplanin. An increase in cell wall thickness of all derivative strains was seen by TEM, with statistically significant values ( P
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heterogeneous resistance to vancomycin in Staphylococcus epidermidis Staphylococcus Haemolyticus and Staphylococcus warneri clinical strains characterisation of glycopeptide susceptibility profiles and cell wall thickening
International Journal of Antimicrobial Agents, 2006Co-Authors: Ana Paula Ferreira Nunes, Lucia M Teixeira, Natalia Lopes Pontes Iorio, Carla Callegario Reis Bastos, L S Fonseca, Thais Soutopadron, Katia Regina Netto Dos SantosAbstract:The population analysis profile (PAP) method as well as analysis of autolytic activity and cellular ultrastructure by transmission electron microscopy (TEM) were used to characterise Staphylococcus epidermidis, Staphylococcus Haemolyticus and Staphylococcus warneri clinical strains with reduced susceptibility to glycopeptides. All strains showed heterogeneous profiles to vancomycin and teicoplanin by the PAP method. Subpopulations that grew in the presence of high concentrations of each drug were selected from the PAP as derivative strains. Their glycopeptide minimal inhibitory concentrations (MICs) were determined and subsequently all parental and derivative strains were grown in one-half of the MIC of vancomycin or teicoplanin. An increase in cell wall thickness of all derivative strains was seen by TEM, with statistically significant values (P<0.01) compared with their respective parental strains. In general, variable rates of autolysis among the strains were observed. Cell wall thickness is an important factor involved in glycopeptide resistance and, in association with PAP results, confirmed the Brazilian coagulase-negative staphylococci clinical isolates as being heteroresistant to glycopeptides. Detection of these heteroresistant organisms is important in order to achieve more judicious use of vancomycin and teicoplanin in hospitals.
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genomic characterization of oxacillin resistant Staphylococcus epidermidis and Staphylococcus Haemolyticus isolated from brazilian medical centres
Journal of Hospital Infection, 2005Co-Authors: Ana Paula Ferreira Nunes, Lucia M Teixeira, L S Fonseca, C C R Bastos, Marlei Gomes Da Silva, Rosana B R Ferreira, Katia Regina Netto Dos SantosAbstract:Studies on the genetic diversity of oxacillin-resistant coagulase-negative staphylococcal (CNS) isolates are important for the control and prevention of infections. The present study evaluated the clonal diversity of oxacillin-resistant Staphylococcus epidermidis (ORSE) and Staphylococcus Haemolyticus (ORSH) strains, isolated from patients in nine Brazilian medical centres by using pulsed-field gel electrophoresis (PFGE) after digestion of bacterial DNA using SmaI. PFGE analysis of ORSE (N=44) and ORSH (N=25) strains showed the presence of 29 restriction profiles clustered in 16 PFGE types, and 21 distinct profiles in 15 PFGE types, respectively, indicating a large genetic diversity among isolates of both of these species. Among the ORSE isolates, 23 (52%) strains belonged to two predominant PFGE types (named A and B), which were observed in most of the hospitals assessed, indicating the spread of these PFGE types in hospitals located in Rio de Janeiro. The spread of PFGE types of ORSH was also detected in some of the hospitals investigated. The results show that PFGE is a suitable tool for epidemiological studies of oxacillin-resistant CNS, and can be used as a basis for infection control procedures for these multiresistant organisms.