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Dive into the research topics where Monica Cristina Souza is active.

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Featured researches published by Monica Cristina Souza.


Journal of Medical Microbiology | 2009

Corynebacterium diphtheriae as an emerging pathogen in nephrostomy catheter-related infection: evaluation of traits associated with bacterial virulence

Débora Leandro Rama Gomes; Carlos Alberto S Martins; Lúcia Maria Dias de Faria; Louisy Sanches dos Santos; Cíntia Silva Santos; Priscila Soares Sabbadini; Monica Cristina Souza; Gabriela B. Alves; Ana Cláudia de Paula Rosa; Prescilla Emy Nagao; Gabriela Andrade Pereira; Raphael Hirata; Ana Luiza Mattos-Guaraldi

Corynebacterium diphtheriae still represents a global medical challenge, particularly due to the significant number of individuals susceptible to diphtheria and the emergence of non-toxigenic strains as the causative agents of invasive infections. In this study, we characterized the clinical and microbiological features of what we believe to be the first case of C. diphtheriae infection of a percutaneous nephrostomy catheter insertion site in an elderly patient with a fatal bladder cancer. Moreover, we demonstrated the potential role of adherence, biofilm formation and fibrin deposition traits in C. diphtheriae from the catheter-related infection. Non-toxigenic C. diphtheriae isolated from the purulent discharge (named strain BR-CAT5003748) was identified by the API Coryne system (code 1 010 324) and a multiplex PCR for detection of dtxR and tox genes. Strain BR-CAT5003748 showed resistance to oxacillin, ceftazidime and ciprofloxacin. In experiments performed in vitro, the catheter isolate was classified as moderately hydrophobic and as moderately adherent to polystyrene surfaces. Glass provided a more effective surface for biofilm formation than polystyrene. Micro-organisms adhered to (>1.5 x 10(6) c.f.u.) and multiplied on surfaces of polyurethane catheters. Microcolony formation (a hallmark of biofilm formation) and amorphous accretions were observed by scanning electron microscopy on both external and luminal catheter surfaces. Micro-organisms yielded simultaneous expression of localized adherence-like and aggregative-like (LAL/AAL) adherence patterns to HEp-2 cells. Interestingly, the coagulase tube test resulted in the formation of a thin layer of fibrin embedded in rabbit plasma by the non-toxigenic BR-CAT5003748 strain. In conclusion, C. diphtheriae should be recognized as a potential cause of catheter-related infections in at-risk populations such as elderly and cancer patients. LAL/AAL strains may be associated with virulence traits that enable C. diphtheriae to effectively produce biofilms on catheter surfaces. Biofilm formation and fibrin deposition could have contributed to the persistence of C. diphtheriae at the infected insertion site and the obstruction of the nephrostomy catheter.


Vector-borne and Zoonotic Diseases | 2010

Corynebacterium ulcerans isolated from an asymptomatic dog kept in an animal shelter in the metropolitan area of Rio de Janeiro, Brazil.

Alexandre A.S.O. Dias; Feliciano Correa Silva Junior; Gabriela Andrade Pereira; Monica Cristina Souza; Thereza Cristina Ferreira Camello; José A.L.D. Damasceno; Luis G. C. Pacheco; Anderson Miyoshi; Vasco Azevedo; Raphael Hirata Junior; Maria Helena Simões Villas Bôas; Ana Luiza Mattos-Guaraldi

Corynebacterium ulcerans was isolated from nares of one asymptomatic dog kept in an animal shelter in the metropolitan area of Rio de Janeiro, Brazil. The RNA polymerase beta subunit-encoding gene was sequenced to confirm the species identity. C. ulcerans strains producing phospholipase D, but not diphtheria toxin, are able to cause severe disease in humans, such as pneumonia and granulomatous nodules in pulmonary tissues. The infection rate varies really widely by region, probably because of the variations in the reported infection rates. Dogs with unapparent C. ulcerans infections may be considered as potentially capable of infecting other animals and humans, including pet owners. Medical and veterinary staff should be aware that asymptomatic animals can carry C. ulcerans and cooperate in eliminating infections and monitoring animals also in the developing countries.


Letters in Applied Microbiology | 2009

Corynebacterium pseudodiphtheriticum isolated from relevant clinical sites of infection: a human pathogen overlooked in emerging countries

Thereza Cristina Ferreira Camello; Monica Cristina Souza; Carlos Alberto S Martins; Paulo Vieira Damasco; Elizabeth Andrade Marques; F.P. Pimenta; Gabriela Andrade Pereira; Raphael Hirata; Ana Luiza Mattos-Guaraldi

Aims:  To examine the occurrence of and to determine the antimicrobial susceptibility of Corynebacterium pseudodiphtheriticum among patients with bacterial infections at a teaching hospital.


Letters in Applied Microbiology | 2008

DNase test as a novel approach for the routine screening of Corynebacterium diphtheriae

F.P. Pimenta; Monica Cristina Souza; Gabriela Andrade Pereira; Raphael Hirata; Thereza Cristina Ferreira Camello; Ana Luiza Mattos-Guaraldi

Aims:  To examine the value of the DNase test as an alternative procedure for differentiating Corynebacterium diphtheriae from Corynebacterium‐like colonies.


Memorias Do Instituto Oswaldo Cruz | 2013

Clonal multidrug-resistant Corynebacterium striatum within a nosocomial environment, Rio de Janeiro, Brazil

Paulo Victor Pereira Baio; Higor Franceschi Mota; Débora Leandro; Rama Gomes; Juliana Nunes Ramos; Lincoln Oliveira Sant; Monica Cristina Souza; Thereza Cristina Ferreira Camello; Raphael Hirata Junior; Verônica Viana Vieira

Corynebacterium striatum is a potentially pathogenic microorganism with the ability to produce outbreaks of nosocomial infections. Here, we document a nosocomial outbreak caused by multidrug-resistant (MDR) C. striatum in Rio de Janeiro, Brazil. C. striatum identification was confirmed by 16S rRNA and rpoB gene sequencing. Fifteen C. striatum strains were isolated from adults (half of whom were 50 years of age and older). C. striatum was mostly isolated in pure culture from tracheal aspirates of patients undergoing endotracheal intubation procedures. The analysis by pulsed-field gel electrophoresis (PFGE) indicated the presence of four PFGE profiles, including two related clones of MDR strains (PFGE I and II). The data demonstrated the predominance of PFGE type I, comprising 11 MDR isolates that were mostly isolated from intensive care units and surgical wards. A potential causal link between death and MDR C. striatum (PFGE types I and II) infection was observed in five cases.


Memorias Do Instituto Oswaldo Cruz | 2009

Microbiological and host features associated with corynebacteriosis in cancer patients: a five-year study

Cas Martins; Lmd Faria; Monica Cristina Souza; Tcf Camello; E Velasco; Raphael Hirata; Lcs Thuler; Ana Luiza Mattos-Guaraldi

During a five-year period, 932 clinical isolates from cancer patients treated in a Brazilian reference centre were identified as corynebacteria; 86% of the cultures came from patients who had been clinically and microbiologically classified as infected and 77.1% of these patients had been hospitalised (71.1% from surgical wards). The adult solid tumour was the most common underlying malignant disease (66.7%). The univariate and multivariate analyses showed that hospitalised patients had a six-fold greater risk (OR = 5.5, 95% CI = 1.15-26.30 p = 0.033) related to 30-day mortality. The predominant species were Corynebacterium amycolatum (44.7%), Corynebacterium minutissimum (18.3%) and Corynebacterium pseudodiphtheriticum (8.5%). The upper urinary tracts, surgical wounds, lower respiratory tracts, ulcerated tumours and indwelling venous catheters were the most frequent sources of C. amycolatum strains. Corynebacterium jeikeium infection occurred primarily in neutropenic patients who have used venous catheters, while infection caused by C. amycolatum and other species emerged mainly in patients with solid tumours.


PLOS Neglected Tropical Diseases | 2013

Molecular Identification of Nocardia Isolates from Clinical Samples and an Overview of Human Nocardiosis in Brazil

Paulo Victor Pereira Baio; Juliana Nunes Ramos; Louisy Sanches dos Santos; Morgana Fonseca Soriano; Elisa Martins Ladeira; Monica Cristina Souza; Thereza Cristina Ferreira Camello; Márcio Garcia Ribeiro; Raphael Hirata Junior; Verônica Viana Vieira; Ana Luiza Mattos-Guaraldi

Background Nocardia sp. causes a variety of clinical presentations. The incidence of nocardiosis varies geographically according to several factors, such as the prevalence of HIV infections, transplants, neoplastic and rheumatic diseases, as well as climate, socio-economic conditions and laboratory procedures for Nocardia detection and identification. In Brazil the paucity of clinical reports of Nocardia infections suggests that this genus may be underestimated as a cause of human diseases and/or either neglected or misidentified in laboratory specimens. Accurate identification of Nocardia species has become increasingly important for clinical and epidemiological investigations. In this study, seven clinical Nocardia isolates were identified by multilocus sequence analysis (MLSA) and their antimicrobial susceptibility was also determined. Most Nocardia isolates were associated to pulmonary disease. Methodology/Principal Findings The majority of Brazilian human isolates in cases reported in literature were identified as Nocardia sp. Molecular characterization was used for species identification of Nocardia nova, Nocardia cyriacigeorgica, Nocardia asiatica and Nocardia exalbida/gamkensis. Data indicated that molecular analysis provided a different Nocardia speciation than the initial biochemical identification for most Brazilian isolates. All Nocardia isolates showed susceptibility to trimethoprim-sulfamethoxazole, the antimicrobial of choice in the treatment nocardiosis. N. nova isolated from different clinical specimens from one patient showed identical antimicrobial susceptibility patterns and two distinct clones. Conclusions/Significance Although Brazil is the worlds fifth-largest country in terms of land mass and population, pulmonary, extrapulmonary and systemic forms of nocardiosis were reported in only 6 of the 26 Brazilian states from 1970 to 2013. A least 33.8% of these 46 cases of nocardiosis proved fatal. Interestingly, coinfection by two clones may occur in patients presenting nocardiosis. Nocardia infection may be more common throughout the Brazilian territory and in other developing tropical countries than is currently recognized and MLSA should be used more extensively as an effective method for Nocardia identification.


Microbiology and Immunology | 2010

Non-opsonic phagocytosis of homologous non-toxigenic and toxigenic Corynebacterium diphtheriae strains by human U-937 macrophages

Cíntia Silva dos Santos; Louisy Sanches dos Santos; Monica Cristina Souza; Fernanda dos Santos Dourado; Alexandre Alves de Souza de Oliveira Dias; Priscila Soares Sabbadini; Gabriela Andrade Pereira; Maulori Curié Cabral; Raphael Hirata Junior; Ana Luíza de Mattos-Guaraldi

As interactions between bacteria and macrophages dictate the outcome of most infectious diseases, analyses of molecular mechanisms of non‐opsonic phagocytosis should lead to new approaches for the prevention of diphtheria and systemic Corynebacterium diphtheriae infections. The present study aimed to evaluate human macrophage–bacteria interactions in the absence of opsonin antibodies and the influence of the tox gene on this process. Homologous C. diphtheriae tox+ and tox– strains were evaluated for adhesion, entering and survival within U‐937 human macrophages at different incubation periods. Higher numbers of viable bacteria associated with and internalized by macrophages were demonstrated for the tox+ strain. However, viable intracellular bacteria were detected at T‐24 hr only for the tox– strain. Cytoskeletal inhibitors, cytochalasin E, genistein and colchicine, inhibited intracellular viability of both strains at different levels. Bacterial replication was evidenced at T‐24 hr in supernatants of monolayers infected with the tox– strain. Host cell death and nuclear alterations were evidenced by the Trypan blue exclusion assay and DAPI fluorescence microscopy. ELISA of histone‐associated DNA fragments allowed detection of apoptosis and necrosis induced by tox+ and tox– strains at T‐1 hr and T‐3 hr. In conclusion, human macrophages in the absence of opsonins may not be promptly effective at killing diphtheria bacilli. The presence of the tox gene influences the susceptibility of C. diphtheriae to human macrophages and the outcome of non‐opsonic phagocytosis. C. diphtheriae strains exhibit strategies to survive within macrophages and to exert apoptosis and necrosis in human phagocytic cells, independent of the tox gene.


Memorias Do Instituto Oswaldo Cruz | 2013

Multiplex polymerase chain reaction to identify and determine the toxigenicity of Corynebacterium spp with zoonotic potential and an overview of human and animal infections

Luciene de Fátima Costa Torres; Dayana Ribeiro; Raphael Hirata; Luis G. C. Pacheco; Monica Cristina Souza; Louisy Sanches dos Santos; Cíntia Silva Santos; Mohammad Salah; Mateus Matiuzzi da Costa; Márcio Garcia Ribeiro; Salah A. Selim; Vasco Azevedo; Ana Luiza Mattos-Guaraldi

Corynebacterium diphtheriae, Corynebacterium ulcerans and Corynebacterium pseudotuberculosis constitute a group of potentially toxigenic microorganisms that are related to different infectious processes in animal and human hosts. Currently, there is a lack of information on the prevalence of disease caused by these pathogens, which is partially due to a reduction in the frequency of routine laboratory testing. In this study, a multiplex polymerase chain reaction (mPCR) assay that can simultaneously identify and determine the toxigenicity of these corynebacterial species with zoonotic potential was developed. This assay uses five primer pairs targeting the following genes: rpoB (Corynebacterium spp), 16S rRNA (C. ulcerans and C. pseudotuberculosis), pld (C. pseudotuberculosis), dtxR (C. diphtheriae) and tox [diphtheria toxin (DT) ]. In addition to describing this assay, we review the literature regarding the diseases caused by these pathogens. Of the 213 coryneform strains tested, the mPCR results for all toxigenic and non-toxigenic strains of C . diphtheriae, C. ulcerans and C. pseudotuberculosis were in 100% agreement with the results of standard biochemical tests and PCR-DT. As an alternative to conventional methods, due to its advantages of specificity and speed, the mPCR assay used in this study may successfully be applied for the diagnosis of human and/or animal diseases caused by potentially toxigenic corynebacterial species.


Memorias Do Instituto Oswaldo Cruz | 2015

Biofilm production by multiresistant Corynebacterium striatum associated with nosocomial outbreak.

Souza Cd; Yuri Vieira Faria; Sant'Anna Lde O; Viana Vg; Seabra Sh; Monica Cristina Souza; Verônica Viana Vieira; Hirata Júnior R; Moreira Lde O; Ana Luiza Mattos-Guaraldi

Corynebacterium striatum is a potentially pathogenic microorganism that causes nosocomial outbreaks. However, little is known about its virulence factors that may contribute to healthcare-associated infections (HAIs). We investigated the biofilm production on abiotic surfaces of multidrug-resistant (MDR) and multidrug-susceptible (MDS) strains of C. striatum of pulsed-field gel electrophoresis types I-MDR, II-MDR, III-MDS and IV-MDS isolated during a nosocomial outbreak in Rio de Janeiro, Brazil. The results showed that C. striatum was able to adhere to hydrophilic and hydrophobic abiotic surfaces. The C. striatum 1987/I-MDR strain, predominantly isolated from patients undergoing endotracheal intubation procedures, showed the greatest ability to adhere to all surfaces. C. striatum bound fibrinogen to its surface, which contributed to biofilm formation. Scanning electron microscopy showed the production of mature biofilms on polyurethane catheters by all pulsotypes. In conclusion, biofilm production may contribute to the establishment of HAIs caused by C. striatum.

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Raphael Hirata Junior

Rio de Janeiro State University

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Gabriela Andrade Pereira

Rio de Janeiro State University

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Raphael Hirata

Rio de Janeiro State University

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Carlos Alberto S Martins

Rio de Janeiro State University

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Cíntia Silva Santos

Rio de Janeiro State University

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