Roberto Martinez

University of São Paulo, São Paulo, Estado de Sao Paulo, Brazil

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Publications (55)162 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: In this study, we report the early expansion, evolution and characterization of a multiresistant Klebsiella pneumoniae clone that was isolated with increasing frequency from inpatients in a tertiary-care university hospital in Brazil. Seven carbapenem- and quinolone-resistant and polymyxin B-susceptible or -resistant K. pneumoniae isolated between December 2012 and February 2013 were investigated. Beta-lactamase and PMQR-encoding genes and the genetic environment were investigated using PCR, sequencing and RFLP. Clonal relatedness was established using XbaI-PFGE, MLST and phylogenetic group characterization. Plasmid analyses included PBRT and hybridization of the S1-PFGE product, pMLST typing and conjugation experiments. Virulence potential was assessed by PCR by searching for ten virulence factor-encoding genes (ureA, fimH, kfuBC, uge, wabG, magA, mrkD, allS, rmpA and cf29a) and by phenotypic tests to analyze the hypermucoviscous phenotype. The genetic context of a multidrug-resistant and extensively drug-resistant K. pneumoniae ST11-KpI clone harboring IncFIIk-Tn4401a-blaKPC-2 and qnrS1, blaCTX-M-2 was found. Moreover, three isolates displayed high resistance to polymyxin B (MICs=32, 32 and 128 mg/L) as well as mucous and hypermucoviscous phenotypes. These bacteria also harbored ureA, fimH, uge, wabG and mrkD, which code for virulence factors associated with binding, biofilm formation and the ability to colonize and escape from phagocytosis. Our study describes the association of important co-resistance and virulence factors in the K. pneumoniae ST11 international high-risk clone, which makes this pathogen successful at infections and points to the quick expansion and evolution of this multiresistant and virulent clone, leading to a pandrug-resistant phenotype and persistent bacteria in a Brazilian hospital.
    Journal of clinical microbiology 05/2014; · 4.16 Impact Factor
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    ABSTRACT: Introduction Pseudomonas aeruginosa isolates related to nosocomial infections are often resistant to multiple antibacterial agents. In this study, antimicrobial combinations were evaluated to detect in vitro synergy against clinical isolates of P. aeruginosa. Methods Four clinical P. aeruginosa isolates were selected at random among other isolates from inpatients treated at the public University hospital in Ribeirão Preto, SP, Brazil. Two isolates were susceptible to imipenem (IPM-S) and several other antimicrobials, while the other two isolates were imipenem and multidrug resistant (IPM-R). The checkerboard method was used to assess the interactions between antimicrobials. Results Combinations of imipenem or other anti-Pseudomonas drugs with complementary antibiotics, such as aminoglycosides, fosfomycin and rifampin, reached synergy rates of 20.8%, 50%, 62.5% and 50% for the two IPM-S and two IPM-R Pseudomonas isolates, respectively. Imipenem, piperacillin-tazobactam and ceftazidime yielded a greater synergy rate than cefepime or ciprofloxacin. Synergist combinations were more commonly observed when the complementary drug was tobramycin (65%) or fosfomycin (57%). Conclusions Some antibacterial combinations led to significant reductions of the minimum inhibitory concentrations of both drugs, suggesting that they could be clinically applied to control infections caused by multidrug-resistant P. aeruginosa.
    Revista da Sociedade Brasileira de Medicina Tropical 01/2013; 46(3). · 0.93 Impact Factor
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    ABSTRACT: Amphotericin B, azole or sulfamide drugs are used for treatment of patients with paracoccidioidomycosis. Among the azole drugs, voriconazole was active in vitro against Paracoccidioides brasiliensis and showed efficacy in the treatment of patients infected with this fungus.In the present study the antifungal activity of voriconazole and of other drugs was compared in a rat model of paracoccidioidomycosis. Wistar rats were inoculated intravenously with the BOAS strain of P. brasiliensis and antifungal drugs were administered to the animals by gavage at the following doses (mg/kg weight/day): voriconazole (5 to 20), ketoconazole (12 to 15), fluconazole (6), itraconazole (4), and sulfamethoxazole-trimethoprim (120 to 150). The antifungal activity of the drugs was assessed by determining the P. brasiliensis colony forming units in the lungs and spleen of the animals at the end of treatment and by a survival study. Voriconazole reduced the total tissue fungal burden of P. brasiliensis, particularly at doses of ≥10mg/kg weight/day but its antifungal activity was less intense than that of fluconazole, itraconazole and sulfamethoxazole-trimethoprim. The mean survival of animals treated with the last three drugs, 29.1±10.7, 26.1± 10.1 and 28.4±9.6 days, respectively, was higher than that achieved with voriconazole 10mg/kg weight/day (18.5±8.3 days) and that observed in untreated animals (15.7±3.6 days). At doses similar to those used for clinical treatment, voriconazole showed lower antifungal activity in experimental rat paracoccidioidomycosis than that obtained with itraconazole and sulfamethoxazole-trimethoprim.
    Revista da Sociedade Brasileira de Medicina Tropical 01/2013; 46(1):79-83. · 0.93 Impact Factor
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    ABSTRACT: The global emergence of vancomycin-resistant Enterococcus faecium (VREfm) has been characterized by a clonal spread of strains belonging to clonal complex 17 (CC17). Genetic features and clonal relationships of 53 VREfm isolated from patients in 2 hospitals in Ribeirao Preto, São Paulo, Brazil, during 2005-2010 were determined as a contribution to the Brazilian evolutionary history of these nosocomial pathogens. All isolates were daptomycin susceptible, vancomycin-resistant, and had the vanA gene. The predominant virulence genes were acm and esp. Only 5 VREfm isolated in 2005-2006 had intact Tn1546, while 81% showed Tn1546 with deleted left extremity and insertion of IS1251 between the vanS and vanH genes. Multilocus sequence typing analysis permitted the identification of 9 different sequence types (STs), with 5 being new ones (656, 657, 658, 659, and 660). Predominant STs were ST412 and ST478, all belonging to CC17, except ST658. This is the first report of the ST78 in Brazil.
    Diagnostic microbiology and infectious disease 09/2012; 74(3):267-71. · 2.45 Impact Factor
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    ABSTRACT: Paracoccidioidomycosis (PCM) is a systemic fungal disease endemic to Latin America and characterized by two clinical presentations, i.e., patients develop either acute/ subacute or chronic clinical manifestations. The differences in clinical presentations are mainly dependent on the host immune response, but may also be related to demographic characteristics of some patients. In this retrospective study, 1,219 PCM cases treated between 1970 and 2009 in a university medical center, located in southeastern Brazil, were analyzed according to their clinical and demographic features. The most affected anatomical sites were lungs (63.8%) and oral mucosa (50.0%), with increasing involvement of these sites in accord with the age of the patients. Generalized lymphadenopathy (28.1%) and skin lesions (29.6%) were more frequent on the first decades of life. Involvement of the larynx (16.1%), gut (7.5%), spleen (4.7%), central nervous system (3.4%), bones and joints (2.2%), and adrenal (2.1%) were also variable according to the age of the host. The acute/subacute form of the disease accounted for 26.4% of PCM cases and, on a multivariate analysis, was inversely associated with aging (OR = 0.8 per year, P < 0.001), and directly associated with female sex (OR = 7.2, P < 0.001), mixed black and white racial background (OR = 2.3, P < 0.001) or black skin color (OR = 4.6, P < 0.001). Based on these findings, we have shown that host immune response, as well as age, gender and ethnicity may influence the clinical presentation of PCM.
    Medical mycology: official publication of the International Society for Human and Animal Mycology 08/2012; · 2.13 Impact Factor
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    ABSTRACT: Although many proteins have been described involved in Escherichia coli colonization and infection, only few reports have shown lectins as important components in these processes. Because the mechanisms underlying E. coli colonization process involving lectins are not fully understood, we sought to identify the presence of other non-described lectins in E. coli. Here, we isolated a 75-kDa protein from E. coli on Sepharose column and identified it as ferric aerobactin receptor (IutA). Since IutA is controversially associated with virulence of some E. coli strains, mainly in uropathogenic E. coli (UPEC), we evaluated the presence of iutA gene in UPEC isolated from patients with urinary infection. This gene was present in only 38% of the isolates, suggesting a weak association with virulence. Because there is a redundancy in the siderophore-mediated uptake systems, we suggest that IutA can be advantageous but not essential for UPEC.
    Revista Latino-Americana de Enfermagem 04/2012; 20(2):340-5. · 0.54 Impact Factor
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    ABSTRACT: Paracoccidioidomycosis has been known for over 100 years, and until now, there were only few estimates of the disease's incidence. We aim to analyze 1,000 cases treated between 1960 and 1999 at Ribeirão Preto city, São Paulo, Brazil, where the disease's incidence range detected was 1.6 to 3.7 cases per 100,000 habitants per year (mean = 2.7 cases/year). We observed a male to female ratio of 6:1 and an age distribution from 3 to 85 years. The acute/subacute form of the disease accounted for 25.4% of cases. Most of the patients (93.5%) had lived or worked in rural areas before the disease development. Smoking and alcoholism were reported by 64.7% and 37.2% of patients, respectively. Comorbidities identified included tuberculosis (8.3%), Chagas' disease (8.6%), and human immunodeficiency virus/acquired immunodeficiency syndrome (4.2%). The present study revealed an area in Brazil where paracoccidioidomycosis is hyperendemic (has the highest reported incidence of this disease); this endemic area is probably caused by geological and climatic conditions as well as intensive agriculture.
    The American journal of tropical medicine and hygiene 09/2011; 85(3):546-50. · 2.53 Impact Factor
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    ABSTRACT: This article reports the spread of bla(KPC-2) in the Sao Paulo and Rio de Janeiro states, facilitated by globally spread K. pneumoniae clonal complex 258 (CC258) clones (ST258, ST11, and ST437) and a diversity of plasmids (IncFII, IncN, and IncL/M, two untypeable plasmids carrying Tn4401a or Tn4401b) successfully disseminated among species of the Enterobacteriaceae (Enterobacter cloacae, Serratia marcescens, and Citrobacter freundii). It also constitutes the first description of sequence type 258 (ST258) in Brazil, which was associated with a nosocomial hospital outbreak in Ribeirao Preto city.
    Antimicrobial Agents and Chemotherapy 07/2011; 55(7):3579-83. · 4.57 Impact Factor
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    ABSTRACT: To report the radiological abnormalities of osteoarticular involvement in paracoccidioidomycosis (PCM). After institutional board approval, the medical records and conventional radiology findings of 19 patients with osseous PCM were retrospectively reviewed. Number, distribution, and lesion characteristics were evaluated in consensus by two experienced musculoskeletal radiologists. The mean age of patients was 16.1 years (range 4-49 years), 11 male and eight female. MSK involvement was the only or the primary presentation of the disease in eight of 19 patients (42.1%). In total, 51 focal bone lesions were detected, being 41 in long bones. In long bones lesions, 19 of 41 (46.4%) were metaphyseal, 12 of 41 (29.3%) meta-epiphyseal, and 12 of 41 (29.3%) diaphyseal. The most common presentation was a geographic osteolytic bone lesion (62.7%), without marginal sclerosis (82.4%) and without periosteal reaction (90.2%). Articular involvement was present in six of 19 patients (31.6%), being two cases of primary arthritis. All encountered bone lesions were osteolytic. Metaphyseal or meta-epiphyseal osteomyelitis of a long bone was the most prevalent osteoarticular manifestation of paracoccidioidomycosis. PCM osteoarticular involvement could be solitary or multifocal, occurs almost exclusively in the acute/subacute clinical form, and it is more common in children and in juvenile patients. Axial skeleton involvement, arthritis, or a disseminated osseous pattern of infection may occasionally occur in this fungal disease.
    Skeletal Radiology 06/2011; 41(2):203-8. · 1.74 Impact Factor
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    ABSTRACT: Occupational HIV infection among healthcare workers is an important issue in exposures involving blood and body fluids. There are few data in the literature regarding the potential and the duration of infectivity of HIV type 1 (HIV-1) in contaminated material under adverse conditions. We quantified HIV-1 viral RNA in 25×8mm calibre hollow-bore needles, after punctures, in 25 HIV-1-infected patients selected during the sample collection. All of the patients selected were between the ages of 18 and 55. Five samples were collected from 16 patients: one sample for the immediate quantification of HIV-1 RNA in the plasma and blood samples from the interior of 4 needles to be analyzed at 0 h, 6 h, 24 h, and 72 h after collection. In nine patients, another test was carried out in the blood from one additional needle, in which HIV-1 RNA was assessed 168 h after blood collection. The method used to assess HIV-1 RNA was nucleic acid sequence-based amplification. Up to 7 days after collection, HIV-1 RNA was detected in all of the needles. The viral RNA remained stable up to 168 h, and there were no statistically significant differences among the needle samples. Although the infectivity of the viral material in the needles is unknown, the data indicate the need to re-evaluate the practices in cases of occupational accidents in which the source is not identified.
    Revista da Sociedade Brasileira de Medicina Tropical 01/2011; 44(6):661-4. · 0.93 Impact Factor
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    ABSTRACT: The thermally dimorphic fungus Paracoccidioides brasiliensis (Pb) is the causative agent of paracoccidioidomycosis (PCM), one of the most frequent systemic mycosis that affects the rural population in Latin America. PCM is characterized by a chronic inflammatory granulomatous reaction, which is consequence of a Th1-mediated adaptive immune response. In the present study we investigated the mechanisms involved in the immunoregulation triggered after a prior contact with cell-free antigens (CFA) during a murine model of PCM. The results showed that the inoculation of CFA prior to the infection resulted in disorganized granulomatous lesions and increased fungal replication in the lungs, liver and spleen, that paralleled with the higher levels of IL-4 when compared with the control group. The role of IL-4 in facilitating the fungal growth was demonstrated in IL-4-deficient- and neutralizing anti-IL-4 mAb-treated mice. The injection of CFA did not affect the fungal growth in these mice, which, in fact, exhibited a significant diminished amount of fungus in the tissues and smaller granulomas. Considering that in vivo anti-IL-4-application started one week after the CFA-inoculum, it implicates that IL-4-CFA-induced is responsible by the mediation of the observed unresponsiveness. Further, the characterization of CFA indicated that a proteic fraction is required for triggering the immunosuppressive mechanisms, while glycosylation or glycosphingolipids moieties are not. Taken together, our data suggest that the prior contact with soluble Pb antigens leads to severe PCM in an IL-4 dependent manner.
    PLoS ONE 01/2011; 6(6):e21423. · 3.73 Impact Factor
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    ABSTRACT: Paracoccidioidomycosis should be differentiated from other opportunistic diseases in human immunodeficiency virus (HIV)/acquired immunodeficiency syndrome (AIDS) patients who live in Latin America. Laboratory investigation can begin with serological tests, which are rapid and efficient. In the present study, double immunodiffusion (DID), counterimmunoelectrophoresis (CIEP) and an enzyme linked immunosorbent assay (ELISA) tests were assessed for the detection of anti-Paracoccidioides brasiliensis antibodies in 40 patients coinfected with HIV. The results were compared to those obtained for 75 non-HIV-infected patients with endemic paracoccidioidomycosis. Anti-P. brasiliensis antibodies were detected in 65% (DID), 79% (CIEP) and 95% (ELISA) of the patients with HIV/AIDS, significantly lower rates than those detected in cases of endemic paracoccidioidomycosis, which were 89%, 99% and 100%, respectively. The reactive sera of HIV-infected patients also showed lower anti-P. brasiliensis antibody titres than those of non-HIV-infected patients. Despite the lower intensity of the specific humoral response, serological tests are useful for the diagnosis of opportunistic paracoccidioidomycosis in the HIV/AIDS population. We suggest optimization of the laboratory diagnosis by combining the ELISA test with CIEP or DID.
    Memórias do Instituto Oswaldo Cruz 11/2010; 105(7):904-7. · 1.36 Impact Factor
  • International journal of gynaecology and obstetrics: the official organ of the International Federation of Gynaecology and Obstetrics 10/2010; 111(1):85-6. · 1.41 Impact Factor
  • Infection Control and Hospital Epidemiology 04/2010; 31(4):429-30. · 4.02 Impact Factor
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    ABSTRACT: Cryptococcus gattii causes a form of endemic mycosis that most commonly affects the lungs and central nervous system of immunocompetent patients living in tropical and subtropical areas of the world. Case report. A 66-year-old man who had chronic obstructive pulmonary disease without HIV infection and had been on systemic corticotherapy for several years developed extensive ulceration of the left forearm that was associated with ipsilateral supraclavicular adenomegaly, consequent to infection with Cryptococcus gattii. The patient was treated with fluconazole 400mg/day for eight months, which led to complete healing of the lesion. This case emphasizes that, although rare, C. gattii may cause opportunistic cutaneous-lymphatic infection in patients living in the southeastern region of Brazil who are immunocompromised through chronic corticotherapy.
    Revista da Sociedade Brasileira de Medicina Tropical 04/2010; 43(2):211-2. · 0.93 Impact Factor
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    Roberto Martinez
    Revista da Sociedade Brasileira de Medicina Tropical 01/2010; 43(4):480. · 0.93 Impact Factor
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    ABSTRACT: Invasive infection and extraintestinal complications are rarely caused by Plesiomonas shigelloides, a waterborne bacterium belonging to the Vibrionaceae family. We report a case of a 16-year-old female patient with sickle beta-zero thalassemia who survived septic shock caused by P. shigelloides associated with secondary acute respiratory distress syndrome and disseminated intravascular coagulation. Treatment with a carbapenem was successful, and the patient recovered without any sequelae. The previous reports of P. shigelloides sepsis are cited, and possible pathogenic mechanisms are discussed.
    Heart & lung: the journal of critical care 01/2010; 39(4):335-9. · 1.04 Impact Factor
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    Roberto Martinez, Maria Janete Moya
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    ABSTRACT: Primary infection with Paracoccidioides brasiliensis has rarely been observed. A 28-year-old male patient presented with a three-month history of fever, respiratory symptoms and malaise. Chest X-rays revealed bilateral apical infiltrates, right pleuritis and hilar lymphadenomegaly. The patient presented with leukocytosis, severe eosinophilia and increasing titers of anti-P. brasiliensis antibodies in serum. To our knowledge, this is the first report of the primary pulmonary lymph node complex of paracoccidioidomycosis accompanied by hypereosinophilia and affecting a previously healthy adult.
    Jornal brasileiro de pneumologia: publicacao oficial da Sociedade Brasileira de Pneumologia e Tisilogia 12/2009; 35(12):1259-62.
  • Alcyone Artioli Machado, Roberto Martinez
    Revista da Sociedade Brasileira de Medicina Tropical 12/2009; 42(6):738. · 0.93 Impact Factor
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    ABSTRACT: To evaluate the effectiveness of the oral application of a 0.12% solution of chlorhexidine for prevention of respiratory tract infections among intensive care unit (ICU) patients. The study design was a double-blind, randomized, placebo-controlled trial. The study was performed in an ICU in a tertiary care hospital at a public university. PATIENTS. Study participants comprised 194 patients admitted to the ICU with a prospective length of stay greater than 48 hours, randomized into 2 groups: those who received chlorhexidine (n = 98) and those who received a placebo (n = 96). Oral rinses with chlorhexidine or a placebo were performed 3 times a day throughout the duration of the patient's stay in the ICU. Clinical data were collected prospectively. Both groups displayed similar baseline clinical features. The overall incidence of respiratory tract infections (RR, 1.0 [95% confidence interval [CI], 0.63-1.60]) and the rates of ventilator-associated pneumonia per 1,000 ventilator-days were similar in both experimental and control groups (22.6 vs 22.3; P = .95). Respiratory tract infection-free survival time (7.8 vs 6.9 days; P = .61), duration of mechanical ventilation (11.1 vs 11.0 days; P = .61), and length of stay (9.7 vs 10.4 days; P = .67) did not differ between the chlorhexidine and placebo groups. However, patients in the chlorhexidine group exhibited a larger interval between ICU admission and onset of the first respiratory tract infection (11.3 vs 7.6 days; P = .05). The chances of surviving the ICU stay were similar (RR, 1.08 [95% CI, 0.72-1.63]). Oral application of a 0.12% solution of chlorhexidine does not prevent respiratory tract infections among ICU patients, although it may retard their onset.
    Infection Control and Hospital Epidemiology 11/2009; 30(10):952-8. · 4.02 Impact Factor

Publication Stats

419 Citations
162.00 Total Impact Points

Institutions

  • 1997–2013
    • University of São Paulo
      • • Department of Clinical Medicine (VCM)
      • • Departamento de Biologia Celular e Molecular e Bioagentes Patogênicos (Ribeirão Preto)
      • • Faculdade de Medicina de Ribeirão Preto (FMRP)
      São Paulo, Estado de Sao Paulo, Brazil
  • 1994–2011
    • Hospital das Clínicas da Faculdade de Medicina de Ribeirão Preto da Universidade de São Paulo
      San Paulo, São Paulo, Brazil
  • 2010
    • Centro Universitário Barão de Mauá
      Mauá, São Paulo, Brazil
  • 2006
    • Universidade de Ribeirão Preto
      Entre Rios, São Paulo, Brazil