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Dive into the research topics where Camila Rizek is active.

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Featured researches published by Camila Rizek.


International Journal of Antimicrobial Agents | 2012

High prevalence of OXA-143 and alteration of outer membrane proteins in carbapenem-resistant Acinetobacter spp. isolates in Brazil

Anna Karina Mostachio; Anna S. Levin; Camila Rizek; Flavia Rossi; Jessika Zerbini; Silvia Figueiredo Costa

Carbapenem resistance amongst Acinetobacter spp. has been increasing in the last decade. This study evaluated the outer membrane protein (OMP) profile and production of carbapenemases in 50 carbapenem-resistant Acinetobacter spp. isolates from bloodstream infections. Isolates were identified by API20NE. Minimum inhibitory concentrations (MICs) for carbapenems were determined by broth microdilution. Carbapenemases were studied by phenotypic tests, detection of their encoding gene by polymerase chain reaction (PCR) amplification, and imipenem hydrolysis. Nucleotide sequencing confirming the enzyme gene type was performed using MegaBACE 1000. The presence of OMPs was studied by sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) and PCR. Molecular typing was performed using pulsed-field gel electrophoresis (PFGE). All isolates were resistant to carbapenems. Moreover, 98% of the isolates were positive for the gene encoding the enzyme OXA-51-like, 18% were positive for OXA-23-like (only one isolate did not show the presence of the insertion sequence ISAba1 adjacent to this gene) and 76% were positive for OXA-143 enzyme. Five isolates (10%) showed the presence of the IMP-1 gene. Imipenem hydrolysing activity was detected in only three strains containing carbapenemase genes, comprising two isolates containing the bla(IMP) gene and one containing the bla(OXA-51/OXA-23-like) gene. The OMP of 43 kDa was altered in 17 of 25 strains studied, and this alteration was associated with a high meropenem MIC (256 μg/mL) in 5 of 7 strains without 43 kDa OMP. On the other hand, decreased OMP 33-36 kDa was found in five strains. The high prevalence of OXA-143 and alteration of OMPs might have been associated with a high level of carbapenem resistance.


Antimicrobial Agents and Chemotherapy | 2014

Susceptibility of Multiresistant Gram-Negative Bacteria to Fosfomycin and Performance of Different Susceptibility Testing Methods

Lauro Vieira Perdigão-Neto; Maura S. Oliveira; Camila Rizek; Claudia Maria Dantas de Maio Carrilho; Silvia Figueiredo Costa; Anna S. Levin

ABSTRACT Fosfomycin may be a treatment option for multiresistant Gram-negative bacteria. This study compared susceptibility methods using 94 multiresistant clinical isolates. With agar dilution (AD), susceptibilities were 81%, 7%, 96%, and 100% (CLSI) and 0%, 0%, 96%, and 30% (EUCAST), respectively, for Acinetobacter baumannii, Pseudomonas aeruginosa, Klebsiella pneumoniae, and Enterobacter spp. Categorical agreement between Etest and AD for Enterobacteriaceae and A. baumannii was ≥80%. Disk diffusion was adequate only for Enterobacter. CLSI criteria for urine may be adequate for systemic infections.


Annals of Clinical Microbiology and Antimicrobials | 2014

Characterization of carbapenem-resistant Pseudomonas aeruginosa clinical isolates, carrying multiple genes coding for this antibiotic resistance

Camila Rizek; Liang Fu; Leticia Cavalcanti dos Santos; Gleice Cristina Leite; Jéssica Fernandes Ramos; Flavia Rossi; Thais Guimaraes; Anna S. Levin; Silvia Figueiredo Costa

BackgroundCarbapenemase genes are one of the most frequent mechanisms reported in carbapenem-resistant P. aeruginosa; however, description of P. aeruginosa co-harbouring two or more carbapenemases is unusual.MethodsIn this study we evaluated the presence of carbapenemase genes and the clonality of P. aeruginosa isolates obtained from a hospital over a 12-year period. A total of 127 isolates of carbapenem-resistant P. aeruginosa recovered from 109 patients feces (four samples), rectal swab (three samples), nasal swab (one sample) and anal abscess (one sample), were evaluated. Minimum inhibitory concentrations of the following antibiotics imipenem, meropenem and polymyxin E were determined by broth microdilution. The molecular profile of isolates was evaluated by pulsed field gel electrophoresis (PFGE). PCR for the following carbapenemase genes blaIMP;blaSPM;blaVIM;blaSIM;blaNDM;blaKPC;blaGES and nucleotide sequencing to confirm the enzyme gene types were performed and compared with the database available on the Internet (BLAST-http://www.ncbi.nlm.nhi.gov/blast/).ResultsAll isolates were carbapenem-resistant, their MIC50 and MIC90 were respectively 64 μg/mL and 256 μg/mL to imipenem and 32 μg/mL and 256 μg/mL to meropenem, all isolates except one (MIC = 8 mg/L) were susceptible to polymyxin E. The most frequent carbapenemase genes identified were blaSPM identified in 41 isolates (32%), followed by 10 with blakpc and 5 with blaVIM (3.9%). All belonged to the class SPM-1 and VIM-2. In 2011, one isolate harbouring three carbapenemase genes (SPM-1, VIM-2 and KPC-2) that belonged to a new clone was identified in a hematopoietic stem cell transplanted patient. Then, 19 carbapenem-resistant P. aeruginosa were identified in an outbreak that occurred in the bone marrow transplant unit, all positive for SPM-1 gene, and 9 (47.3%) harbored both SPM-1 and KPC.ConclusionOur findings showed that PCR for KPC gene should be performed to evaluate carbapenem resistance in P. aeruginosa and that this agent can harbor more than one carbapenemase gene. Attention should be focused on the possible rapid spread of KPC in P. aeruginosa isolates and for the fact that P. aeruginosa may become a reservoir of this transmissible resistance mechanism.


Journal of Infection and Chemotherapy | 2015

In vitro activity of potential old and new drugs against multidrug-resistant gram-negatives

Camila Rizek; Juliana Rosa Ferraz; Inneke M. van der Heijden; Mauro Cintra Giudice; Anna Karina Mostachio; Jorge Isaac Garcia Paez; Claudia Maria Dantas de Maio Carrilho; Anna S. Levin; Silvia Figueiredo Costa

BACKGROUND The aim of this study was to evaluate the in vitro susceptibility of MDR gram-negatives bacteria to old drugs such as polymyxin B, minocycline and fosfomycin and new drugs such as tigecycline. METHODS One hundred and fifty-three isolates from 4 Brazilian hospitals were evaluated. Forty-seven Acinetobacter baumannii resistant to carbapenens harboring adeB, blaOxA23, blaOxA51, blaOxA143 and blaIMP genes, 48 Stenotrophomonas maltophilia including isolates resistant to levofloxacin and/or trimethoprim-sulfamethoxazole harboring sul-1, sul-2 and qnrMR and 8 Serratia marcescens and 50 Klebsiella pneumoniae resistant to carbapenens harboring blaKPC-2 were tested to determine their minimum inhibitory concentrations (MICs) by microdilution to the following drugs: minocycline, ampicillin-sulbactam, tigecycline, and polymyxin B and by agar dilution to fosfomycin according with breakpoint criteria of CLSI and EUCAST (fosfomycin). In addition, EUCAST fosfomycin breakpoint for Pseudomonas spp. was applied for Acinetobacter spp and S. maltophilia, the FDA criteria for tigecycline was used for Acinetobacter spp and S. maltophilia and the Pseudomonas spp polymyxin B CLSI criterion was used for S. maltophilia. RESULTS Tigecycline showed the best in vitro activity against the MDR gram-negative evaluated, followed by polymyxin B and fosfomycin. Polymyxin B resistance among K. pneumoniae was detected in 6 isolates, using the breakpoint of MIC > 8 ug/mL. Two of these isolates were resistant to tigecycline. Minocycline was tested only against S. maltophilia and A. baumannii and showed excellent activity against both. CONCLUSIONS Fosfomycin seems to not be an option to treat infections due to the A. baumannii and S. maltophilia isolates according with EUCAST breakpoint, on the other hand, showed excellent activity against S. marcescens and K. pneumoniae.


Journal of global antimicrobial resistance | 2016

Virulence and resistance pattern of a novel sequence type of linezolid-resistant Enterococcus faecium identified by whole-genome sequencing

Gladys Villas Boas do Prado; Ana Paula Marchi; Luisa Zanolli Moreno; Camila Rizek; Ulisses Amigo; Andrea Micke Moreno; Flavia Rossi; Thais Guimaraes; Anna S. Levin; Silvia Figueiredo Costa

Empirical use of linezolid has been advocated in neutropenic febrile patients colonised by vancomycin-resistant enterococci (VRE) because of the risk of bloodstream infection (BSI). This study aimed to genetically describe a vancomycin-resistant Enterococcus faecium (VREfm) BSI isolate resistant to linezolid (VRLRE) in a patient previously colonised by VREfm and to determine the incidence of colonisation and infection by VREfm in a bone marrow transplant unit over a 10-year period. Data for VREfm colonisation and infection were evaluated. PCR for the vanA and vanB genes, pulsed-field gel electrophoresis (PFGE) and microdilution antimicrobial susceptibility testing (vancomycin, teicoplanin, linezolid and aminoglycosides) were performed. Three isolates, including the VRLRE, were selected for whole-genome sequencing by Ion Torrent™, with E. faecium CP006620-Aus0085 used as a reference. Eighty-seven VREfm were analysed; all were linezolid-susceptible and harboured vanA, except for one blood isolate from a febrile neutropenic patient colonised by VREfm who received linezolid for 12 days and developed a BSI by VRLRE (linezolid MIC≥8μg/mL). Linezolid resistance was associated with a G2576T mutation in the 23SrRNA gene. PFGE analysis demonstrated that the 87 isolates belonged to four major clusters; however, the VRLRE presented only 50% similarity. Three sequence types (STs) were identified: ST412 (the predominant clone, which was more virulent compared with the other isolates); ST478 (linezolid-susceptible VREfm); and a novel ST named ST987 (VRLRE). SNP analysis showed a higher similarity between linezolid-susceptible VREfm and the predominant clone compared with VRLRE. VRLRE presented a G2576T mutation and belonged to a novel ST (ST987).


Journal of Medical Microbiology | 2017

High mortality of bloodstream infection outbreak caused by carbapenem-resistant P. aeruginosa producing SPM-1 in a bone marrow transplant unit

Lucas Chaves; Lísia Moura Tomich; Matias C. Salomão; Gleice Cristina Leite; Jéssica Fernandes Ramos; Roberta Ruedas Martins; Camila Rizek; Patrícia R. Neves; Marjorie Vieira Batista; Ulysses Amigo; Thais Guimaraes; Anna S. Levin; Silvia Figueiredo Costa

PURPOSE Carbapenem resistance in P. aeruginosa is increasing worldwide. In Brazil, SPM-1 is the main P. aeruginosa carbapenemase identified. Little is known about the virulence factor in SPM-1 clones.Methodolgy. We describe a carbapenem-resistant P. aeruginosa bloodstream infection (CRPa-BSI) outbreak in a bone marrow transplant Unit (BMT). Twenty-nine CRPa-BSI cases were compared to 58 controls. Microbiological characteristics of isolates, such as sensitivity, carbapenemase gene PCR for P. aeruginosa, and PFGE are described, as well as the whole-genome sequence (WGS) of three strains.Results/Key findings. The cultures from environmental and healthcare workers were negative. Some isolates harboured KPC and SPM. The WGS showed that the 03 strains belonged to ST277, presented the same mutations in outer membrane protein, efflux pump, and virulence genes such as those involved in adhesion, biofilm, quorum-sensing and the type III secretion system, but differ regarding the carbapenemase profile. A predominant clone-producing SPM harbouring Tn 4371 was identified and showed cross-transmission; no common source was found. Overall mortality rate among cases was 79 %. The first multivariate analysis model showed that neutropenia (P=0.018), GVHD prophylaxis (P=0.016) and prior use of carbapenems (P=0.0089) were associated with CRPa-BSI. However, when MASCC>21 points and platelets were added in the final multivariate analysis, only prior use of carbapenems remained as an independent risk factor for CRPa-BSI (P=0.043). CONCLUSIONS The predominant clone belonging to ST277 showed high mortality. Carbapenem use was the only risk factor associated with CRPa-BSI. This finding is a wake-up call for the need to improve management in BMT units.


Revista Do Instituto De Medicina Tropical De Sao Paulo | 2016

COMPARISON OF METHODS TO IDENTIFY Neisseria meningitidis IN ASYMPTOMATIC CARRIERS.

Camila Rizek; André Machado Luiz; Gracilene Ramos de Assis; Silvia Figueiredo Costa; Anna S. Levin; Marta Heloisa Lopes

SUMMARY Neisseria meningitidis is a cause of several life-threatening diseases and can be a normal commensal in the upper respiratory tract of healthy carriers. The carrier rate is not well established especially because there is no standard method for the isolation of N. meningitidis. Therefore, the aim of this study was to compare identification methods for the carrier state. Two swabs were collected from 190 volunteers: one was cultured and the other had DNA extracted directly from the sample. The Polymerase Chain Reaction (PCR) was performed to determine species and serogroups and compared the results between the methods. PCR for species determination used two pairs of primers and when there was only one amplicon, it was sequenced. The culture technique was positive in 23 (12.1%) subjects while the direct extraction method was positive in 132 (69.5%), p < 0.001. Among the 135 subjects with positive N. meningitides tests, 88 (65.2%) were serogroup C; 3 (2.2%) serogroup B; 5 (3.7%) were positive for both serogroup B and C, and 39 (28.9%) did not belong to any of the tested serogroups. In this study, PCR from DNA extracted directly from swabs identified more N. meningitidis asymptomatic carriers than the culture technique.


Journal of global antimicrobial resistance | 2018

Multidrug-resistant Stenotrophomonas maltophilia : description of new MLST profiles, resistance and virulence genes using whole genome sequencing

Camila Rizek; Daniel Jonas; Jorge Isaac Garcia Paez; Juliana Ferraz Rosa; Lauro Vieira Perdigão Neto; Roberta Ruedas Martins; Luisa Zanolli Moreno; Alfio Rossi Junior; Anna S. Levin; Silvia Figueiredo Costa

OBJECTIVES Stenotrophomonas maltophilia is an opportunistic pathogen that has high intrinsic and acquired antimicrobial resistance, with great genetic diversity. The aim of this study was to characterise four S. maltophilia clinical isolates displaying different susceptibility profiles using whole-genome sequencing. METHODS The whole genomes of four clinical isolates of S. maltophilia from three patients were sequenced using Ion Torrent™ PGM technology. The isolates presented different susceptibilities to trimethoprim/sulfamethoxazole (SXT) and levofloxacin. RESULTS Three new multilocus sequence typing (MLST) profiles were identified (ST144, ST172 and ST173), differing in virulence and resistance genes. The ST172 isolate had more genes related to toxins than related to motility or adhesion and had different types of efflux pumps than the other isolates. The SXT-resistant strains belonged to ST172 or ST144 and did not harbour the sul1, sul2 or dfrA resistance genes. Strains I and II, from the same patient and belonging to the same ST but differing in resistance to SXT, had all of the resistance genes searched for in common, except for the SmeABC efflux pump complex genes that were only found in the SXT-resistant strain. All strains, including the strain susceptible to levofloxacin, harboured the qnrB gene, which may question the importance of this gene in determining levofloxacin resistance in S. maltophilia. CONCLUSION Here we describe three new MLST profiles. Resistance to SXT in these strains appears to be associated with efflux pumps.


American Journal of Infection Control | 2018

Evaluation of adenosine triphosphate test for cleaning assessment of gastroscopes and the effect on workload in a busy endoscopy center

Cristiane Schmitt; Amanda Luiz Pires Maciel; Icaro Boszczowski; Thaís Pereira da Silva; Eliane Aparecida Job Neves; Giulio Fabio Rossini; Camila Rizek; Silvia Figueiredo Costa; Rogério F. Lourenço; Michelle J. Alfa

HighlightsAdenosine triphosphate (ATP) test failed more than culture and protein tests.The inclusion of ATP testing after a single cleaning increased the length of time for the whole procedure (cleaning plus testing cleanliness) by 50%.First cleaning: 70.8% of gastroscopes failed the ATP test; 58.3% of gastroscopes had no microbial growth; and in 91.7% of gastroscopes the protein was undetectable.Second cleaning: 64.7% of gastroscopes still failed the ATP test. Two samples had bacterial growth, and none had protein detected.Poor correlation was found between ATP test and culture. Objective Using adenosine triphosphate (ATP) tests to assess manual cleaning of gastroscopes and to determine the associated workload in a busy endoscopy unit. Methods Patient‐used gastroscopes were sampled before and after cleaning to assess ATP levels, bioburden, and protein. Samples were collected by flushing 20 mL of sterile water through the biopsy port to the distal end. Time spent for reprocessing and performing the ATP test was recorded. Results Twenty‐four samples were collected from 10 gastroscopes. After manual cleaning, 14/24 (58.3%) samples had no microbial growth (mean, 21 colony‐forming units/cm2), and in 22/24 (91.7%) samples the protein was undetectable (mean, 0.04 &mgr;g/cm2). ATP test was above the cutoff (200 relative light units [RLU]) in 17/24 (70.8%) samples (mean, 498 RLU). After the second cleaning, 11/17 (64.7%) gastroscopes still failed the ATP test (mean, 321.2 RLU). The mean time spent to perform manual cleaning and ATP tests was 16 and 8 minutes, respectively. Hence, each test increased the length of time for cleaning plus testing cleanliness by 50%. Conclusion Further studies regarding the optimal cutoff for ATP tests are needed. ATP tests for cleaning monitoring are easy to perform and provide immediate feedback to the team. However, the increased workload needs to be considered.


BMC Microbiology | 2017

Clonality, outer-membrane proteins profile and efflux pump in KPC- producing Enterobacter sp. in Brazil

Juliana Ferraz Rosa; Camila Rizek; Ana Paula Marchi; Thais Guimaraes; L.N. Miranda; Claudia Maria Dantas de Maio Carrilho; Anna S. Levin; Silvia Figueiredo Costa

BackgroundCarbapenems resistance in Enterobacter spp. has increased in the last decade, few studies, however, described the mechanisms of resistance in this bacterium. This study evaluated clonality and mechanisms of carbapenems resistance in clinical isolates of Enterobacter spp. identified in three hospitals in Brazil (Hospital A, B and C) over 7-year.MethodsAntibiotics sensitivity, pulsed-field gel electrophoresis (PFGE), PCR for carbapenemase and efflux pump genes were performed for all carbapenems-resistant isolates. Outer-membrane protein (OMP) was evaluated based on PFGE profile.ResultsA total of 130 isolates of Enterobacter spp were analyzed, 44/105 (41, 9%) E. aerogenes and 8/25 (32,0%) E. cloacae were resistant to carbapenems. All isolates were susceptible to fosfomycin, polymyxin B and tigecycline. KPC was present in 88.6% of E. aerogenes and in all E. cloacae resistant to carbapenems. The carbapenems-resistant E. aerogenes identified in hospital A belonged to six clones, however, a predominant clone was identified in this hospital over the study period. There is a predominant clone in Hospital B and Hospital C as well. The mechanisms of resistance to carbapenems differ among subtypes. Most of the isolates co-harbored blaKPC, blaTEM and /or blaCTX associated with decreased or lost of 35–36KDa and or 39 KDa OMP. The efflux pump AcrAB-TolC gene was only identified in carbapenems-resistant E. cloacae.ConclusionsThere was a predominant clone in each hospital suggesting that cross-transmission of carbapenems-resistant Enterobacter spp. was frequent. The isolates presented multiple mechanisms of resistance to carbapenems including OMP alteration.

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Anna S. Levin

University of São Paulo

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Flavia Rossi

University of São Paulo

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