ABSTRACT Background: The timely diagnosis of tuberculous meningitis (TBM) is challenging. Molecular diagnostic tools are necessary for TBM, particularly in low- and middle-income countries. Objectives: We aimed to calculate the diagnostics characteristics of Xpert MTB/RIF for the detection of Mycobacterium tuberculosis in the cerebrospinal fluid (CSF) and the frequency of rifampicin (RIF)-resistance in the CSF samples. Methods: A total of 313 consecutive CSF samples were studied and categorized into TBM definite, probable, possible, or not TBM cases based on the clinical, laboratory, and imaging data. Results: For the definite TBM cases (n=7), the sensitivity, specificity, efficiency, and positive likelihood ratio were 100, 97, 97, and 38%, respectively. However, for the TBM definite associated with the probable cases (n=24), the sensitivity decreased to 46%. All CSF samples that were Xpert MTB/RIF-positive were RIF susceptible. Conclusion: Xpert MTB/RIF showed high discriminating value among the microbiology-proven TBM cases, although the values for the probable and possible TBM cases were reduced. Xpert MTB/RIF contributes significantly to the diagnosis of TBM, mainly when coupled with the conventional microbiological tests and clinical algorithms.

RESUMO Introdução: O diagnóstico da meningite tuberculosa (TBM) é desafiador. Ferramentas de diagnóstico molecular são necessárias para esse diagnóstico, particularmente em países de baixa e média renda. Objetivos: Calcular as características diagnósticas do Xpert MTB/RIF para a detecção de Mycobacterium tuberculosis no líquido cefalorraquidiano (LCR) e a frequência de resistência à rifampicina (RIF) nas amostras do LCR. Métodos: Um total de 313 amostras consecutivas de LCR foram estudadas e categorizadas em casos de TBM definida, provável, possível ou não TBM, com base nos dados clínicos, laboratoriais e de imagem. Resultados: Para os casos definidos de TBM (n=7), sensibilidade, especificidade, eficiência e razão de verossimilhança positiva foram de 100, 97, 97 e 38%, respectivamente. No entanto, para os casos de TBM definidos associados aos prováveis (n=24), a sensibilidade diminuiu para 46%. Todas as amostras de LCR que foram positivas para Xpert MTB/RIF foram suscetíveis a RIF. Conclusão: O Xpert MTB/RIF mostrou alto valor discriminante entre os casos TBM comprovados por microbiologia, porém o valor nos casos prováveis e possíveis de TBM foram reduzidos. O Xpert MTB/RIF contribui significativamente para o diagnóstico de TBM, principalmente quando associado aos testes microbiológicos convencionais e algoritmos clínicos.

Abstract Background Gram-negative bacilli (GNB), notably Acinetobacter spp., Pseudomonas spp., and Klebsiella spp., are becoming increasingly resistant to carbapenems and are associated with high health care costs and mortality, becoming a global concern. Objective To determine the prevalence rates of carbapenem resistance among Acinetobacter spp., Pseudomonas spp., and Klebsiella spp. in the main sites of nosocomial infection at a tertiary care hospital in southern Brazil and the consequent therapeutic implications. Methods Cultures processed at the institution’s laboratory in 2017 were analyzed, and those positive for Acinetobacter spp., Pseudomonas spp., and Klebsiella spp. were identified. Antibiograms were evaluated for meropenem sensitivity following the Clinical Laboratory Standards Institute guidelines. Results Acinetobacter spp. had the lowest prevalence among the three GNB, and resistance of this pathogen to meropenem at different sites of infection ranged from 36% (blood) to 82% (respiratory tract). Pseudomonas spp. was highly prevalent at the respiratory tract (31%) and had a high resistance rate to meropenem in rectal swab samples (71%), but a relatively low frequency at infection sites (skin/soft tissue, 13%; blood, 25%). Klebsiella spp. was identified in 7.5% of the blood cultures and 15% of the urine cultures and was the chief colonizer among all pathogens, representing 54% of all rectal swab samples, of which 53% were meropenem resistant. At sites of infection, rates of Klebsiella spp. resistant to meropenem ranged from 19% (skin) to 55% (vascular catheter). Conclusions The prevalence of carbapenem-resistant GNB at our hospital was relatively low compared to national and international data; thus, meropenem remains a good therapeutic option against these bacteria. Other antibiotics effective against GNB, such as ceftazidime, cefepime, and piperacillin-tazobactam, can be used in most cases, while meropenem should be reserved for patients with sepsis. Strict contact precaution measures are still needed, given the high resistance rate observed at the colonizing site.

RESUMO As meningites bacterianas (MB) estão associadas à alta morbidade e mortalidade. O lactato no líquido cefalorraquidiano (LCR) pode ser usado como biomarcador de prognóstico nas MB. A hipótese desse estudo é que os níveis de lactato no LCR se mantém elevados entre pacientes com MB aguda que evoluem para óbito, ao contrário do que ocorre em pacientes com bom prognóstico. Objetivo: Avaliar o uso potencial do lactato e outros marcadores no LCR como indicador de prognóstico na MB aguda. Métodos: Foi realizado um estudo retrospectivo longitudinal da dinâmica dos biomarcadores bioquímicos, celulares e físicos no LCR. Foram analisadas 223 amostras de 49 pacientes com MB aguda com bactérias identificadas por cultura do LCR. Os participantes foram divididos em dois grupos de acordo com o desfecho: óbito (n = 9; 18,37%) e não óbito (n = 40; 81,63%). Todos os participantes receberam antibioticoterapia adequada. Resultados: No modelo de regressão logística, as variáveis que diferiram significativamente entre os dois grupos foram concentração de lactato na amostra final de LCR, xantocromia e variação da concentração de glicose entre a primeira e a última amostra de LCR. A alteração desses fatores indicou desfechos negativos (óbito), enquanto a diminuição do número de leucócitos e da porcentagem de neutrófilos, assim como a normalização da concentração de lactato no LCR foram preditores de bom prognóstico. Conclusão: O estudo confirmou a hipótese inicial. A análise longitudinal do lactato no LCR é um importante preditor de prognóstico na MB aguda.

ABSTRACT Bacterial meningitis (BM) is associated with a high morbidity and mortality. Cerebrospinal fluid (CSF) lactate may be used as a prognostic marker of this condition. We hypothesized that CSF lactate levels would remain elevated in participants who died of acute BM compared with those who recovered from this disease. Objective: To evaluate the potential use of lactate and other CSF biomarkers as prognostic markers of acute BM outcome. Methods: This retrospective, longitudinal study evaluated dynamic CSF biomarkers in 223 CSF samples from 49 patients who fulfilled the inclusion criteria of acute BM, with bacteria identified by CSF culturing. The participants were grouped according to outcome: death (n = 9; 18.37%) and survival (n = 40; 81.63%). All participants received appropriate antibiotic treatment. Results: In the logistic regression model, lactate concentration in the final CSF sample, xanthochromia, and CSF glucose variation between the first and last CSF samples were predictors of a poor outcome (death). In contrast, decrease in CSF white blood cell count and CSF percentage of neutrophils, increase in the percentage of lymphocytes, and normalization of the CSF lactate concentration in the last CSF sample were predictors of a good prognosis. Conclusion: The study confirmed the initial hypothesis. The longitudinal analysis of CSF lactate is an important predictor of prognosis in acute BM.

ABSTRACT BACKGROUND: Cell phones have become indispensable for professional activities, including healthcare. Thus, they are possible sources of bacterial contamination. There is a scarcity of data in the literature regarding identification of risk factors for contamination of cell phones with pathogenic bacteria. OBJECTIVE: To compare the prevalence rates of Staphylococcus aureus (S. aureus), methicillin-resistant S. aureus (MRSA) and/or Enterobacteriaceae on cell phones belonging to hospital healthcare staff and university students in Curitiba, Paraná, Brazil, and to identify variables associated with such contamination. DESIGN AND SETTING: Cross-sectional study conducted in a public university’s referral hospital and lecture buildings in 2017. METHODS: We sampled the surface of cell phones using the dipslide method, with Baird-Parker agar and Escherichia coli-coliform chromogenic (ECC) agar. We assessed the population’s sociodemographic, behavioral and hygiene characteristics through interviews. Possible presence of S. aureus colonies was confirmed using agglutination tests, with evaluation of methicillin sensitivity. Colonies in ECC medium were counted. Stepwise logistic regression (forward P < 0.15) was performed to identify characteristics associated with bacterial contamination. RESULTS: The prevalence rates of S. aureus, MRSA and Enterobacteriaceae were, respectively, 32%, 4% and 3%. No difference was found between the hospital and university-based populations (P > 0.05). The only variable associated with bacterial contamination was the use of cloth/velvet/leather phone cases (odds ratio: 2.92; 95% confidence interval: 1.08-7.91). CONCLUSIONS: Potentially pathogenic bacteria were prevalent on the cell phones of this hospital and university population. Use of phone cases made of cloth-like material should be discouraged, especially in hospital settings.

RESUMO Introdução: Diagnosticar infecções em pacientes da unidade de terapia intensiva (UTI) é vital para implementar terapias apropriadas. A contagem automatizada de granulócitos imaturos (IG) em analisadores hematológicos é rápida e sem custos adicionais. A taxa de IG elevada está associada a infecções. Objetivos: Avaliar IG como indicador de infecção em pacientes adultos da UTI do Complexo Hospital de Clínicas da Universidade Federal do Paraná (CHC-UFPR) em comparação com culturas de materiais biológicos (padrão-ouro). Material E Métodos: Foram analisadas amostras de 200 pacientes adultos com suspeita de infecção da UTI do CHC-UFPR. As contagens automatizadas de granulócitos imaturos absolutas (IG#) e relativas (IG%) foram realizadas no Sysmex-XN-3000, e as culturas e as hemoculturas, manualmente ou no Bactec-FX. As características de desempenho de teste diagnóstico para IG# e IG% foram avaliadas. Resultados: Os intervalos de referência (IR) obtidos para IG# e IG% foram 0,06 × 103/µl e 0,6%, respectivamente, com sensibilidade para ambos de 74,4% e especificidade de 25,3% para IG# e 26,6% para IG%. A curva receiver operating characteristic (ROC) mostrou valor de corte de 0,33 × 103/µl para IG#, sensibilidade de 28%, especificidade de 82,3% e área sob a curva (AUC) de 0,521. Para IG%, o valor de corte foi de 1,35%, sensibilidade de 44,6%, especificidade de 64,6% e AUC de 0,532. Valores de corte de IG% < 3% aumentaram a especificidade para 88%. Conclusão: IRs de IG% e IG# apresentaram sensibilidade elevada e são úteis na triagem de infecção nos pacientes da UTI. Os VCs demonstrados pelas curvas ROC para IG% e IG# apresentaram elevada especificidade, sendo, portanto, úteis para exclusão de diagnóstico de sepse nos pacientes da UTI. IG mostrou-se útil para triagem e confirmação de infecção em pacientes de UTI.

ABSTRACT Introduction: Diagnosing infections in intensive care unit (ICU) patients is vital to provide appropriate therapies. Hematological analyzers perform automated immature granulocyte counts (IG) quickly and with no additional cost when compared to traditional microbiological cultures. Elevated IG is directly associated with infections and inflammation. Objectives: Evaluate IG as infection marker in adult inpatients at the ICU-Complexo Hospital de Clínicas da Universidade Federal do Paraná (CHC-UFPR), compared to cultures of biological materials (gold standard). Material And Methods: Samples of 200 adult inpatients at CHC-UFPR ICU with suspected infection were used. Absolute (IG#) and relative (IG%) counts were performed on the Sysmex XN-3000. Cultures and blood cultures were performed either manually or on Bactec FX. Diagnostic accuracy and agreement for IG# and IG% were evaluated. Results: The reference intervals (RI) obtained for IG# and IG% were 0.06 × 103/µl and 0.6%, respectively, with sensitivity for both of 74.4% and specificity of 25.3% for IG#, and 26.6% for IG%. The receiver operating characteristic (ROC) curve showed cut-off value of 0.33 × 103/µl for IG#, sensitivity of 28%, specificity of 82.3%, and area under the curve (AUC) of 0.521. For IG%, cut-off value was 1.35%, sensitivity 44.6%, specificity 64.6%, and AUC 0.532. CV < 3% increased specificity to 88%. Conclusion: RI of IG% and IG# showed high sensitivity and are useful in screening for infection in ICU patients. The CVs demonstrated by the ROC curves showed high specificity and are helpful on the exclusion of sepsis diagnosis in ICU patients. IG was shown to be useful for screening and confirmation of infection in ICU patients.

RESUMEN Introducción: Diagnosticar infecciones en pacientes de la unidad de cuidados intensivos (UCI) es de suma importancia para proporcionar el tratamiento adecuado. El contaje automatizado de granulocitos inmaduros (GI) en analizadores hematológicos es rápido y sin costes adicionales. La elevada tasa de GI está asociada a infecciones. Objetivos: Evaluar GI como indicador de infección en pacientes adultos de la UCI del Complexo Hospital de Clínicas da Universidade Federal do Paraná (CHC-UFPR) en comparación a culturas de materiales biológicos (estándar de oro). Material Y Métodos: Se analizaron muestras de 200 pacientes adultos con sospecha de infección de la UCI del CHC-UFPR. Los conteos automatizados de granulocitos inmaduros absolutos (GI#) e relativos (GI%) se realizaron en el Sysmex-XN-3000, y los cultivos y hemocultivos, manualmente o en el Baetec-FX. Se han evaluado precisión diagnóstica y concordancia para GI# y GI%. Resultados: Los rangos de referencia obtenidos para GI# y GI% fueron 0,06 × 103/µl y 0,6%, respectivamente, con sensibilidad para ambos de 74,4% y especificidad de 25,3% para IG# y 26,6% para IG%. La curva receiver operating characteristic (ROC) ha mostrado valor de corte de 0,33 × 103/µl para IG#, sensibilidad de 28%, especificidad de 82,3% y área bajo la curva (AUC) de 0,521. Para GI%, el valor de corte ha sido 135%, sensibilidad de 44,6%, especificidad de 64,6% y AUC de 0,532. Valores de corte de GI% < 3% aumentaron la especificidad para 88%. Conclusión: Rangos de referencia de GI% y GI# presentaron sensibilidad elevada y son útiles en el triaje de infecciones en pacientes de UCI. Los valores de corte enseñados por las curvas ROC presentaron alta especificidad, permitiendo la identificación adecuada de los pacientes sanos. GI se ha mostrado útil para triaje y confirmación de infección en pacientes de UCI.

RESUMO Este estudo avaliou as características funcionais da reação em cadeia da polimerase (PCR) multiplex para amostras de líquido cefalorraquidiano (LCR) de pacientes com características celulares e bioquímicas de meningite bacteriana aguda e culturas de LCR positivas ou negativas. Métodos: O PCR multiplex foi realizado em 36 amostras de LCR: meningite bacteriana aguda comprovada por cultura (n = 7), meningite bacteriana aguda com cultura negativa (n = 17), meningite linfocítica (n = 8) e LCR normal (n = 4). As características funcionais do PCR multiplex foram avaliadas para meningite bacteriana definitiva e provável, utilizando cultura positiva, características citológicas e bioquímicas do LCR como padrão-ouro. Resultados: O PCR multiplex do LCR foi eficiente no grupo com características celulares e bioquímicas do LCR de meningite bacteriana, mas com cultura do LCR negativa. Este grupo demonstrou especificidade, valor preditivo positivo e eficiência altos. Conclusões: Os autores concluíram que o PCR multiplex do LCR pode melhorar a velocidade e a precisão do diagnóstico de meningite bacteriana em um ambiente clínico como complemento aos ensaios imunológicos e bacteriológicos clássicos no LCR. Também é útil para meningite bacteriana aguda com cultura de LCR negativa.

ABSTRACT This study evaluated the operational characteristics of the multiplex polymerase chain reaction (PCR) for cerebrospinal fluid (CSF) from patients with cellular and biochemical characteristics of acute bacterial meningitis and positive or negative CSF cultures. Methods: Multiplex PCR was performed for 36 CSF samples: culture-proven acute bacterial meningitis (n = 7), culture-negative acute bacterial meningitis (n = 17), lymphocytic meningitis (n = 8), and normal CSF (n = 4). The operational characteristics of multiplex PCR were evaluated with definite and probable bacterial meningitis, using culture positive, cytological and biochemical CSF characteristics as the gold standard. Results: Multiplex PCR for CSF was efficient in the group with CSF cellular and biochemical characteristics of acute bacterial meningitis but with a negative CSF culture. This group demonstrated high specificity, positive predictive value, and efficiency. Conclusions: Multiplex PCR for CSF can improve the speed and accuracy of acute bacterial meningitis diagnosis in a clinical setting as a complement to classical immunological and bacteriological assays in CSF. It is also useful for CSF culture-negative acute bacterial meningitis.

Abstract Ralstonia mannitolilytica, a Gram-negative bacterium, is rarely isolated in clinical laboratories. It has been associated with outbreaks due to its ability to survive in liquid media and hospital devices. We describe three cases of bacteremia caused by R. mannitolilytica in a neonatal intensive care unit in Curitiba, Southern Brazil. All isolates presented the same PFGE profile. The common source of infection was undetected in surveillance cultures for the outbreak survey. All patients received antimicrobial treatment and were discharged from the maternity. Due to the characteristics of the microorganism, clinicians and microbiologists should pay attention to the emergence of Ralstonia spp. infections.

Abstract INTRODUCTION: Bloodstream infections can be fatal, and timely identification of the etiologic agent is important for treatment. METHODOLOGY: An alternative method, consisting of direct identification and susceptibility testing of blood culture bottles using the automated VITEK 2® system, was assessed. RESULTS: All 37 of the Gram-negative bacilli (GNB) identifications and 57.1% of the 28 Gram-positive cocci (GPC) identifications matched those obtained with standard methods. In susceptibility testing, the agreement was greater than 90%. CONCLUSIONS: This alternative methodology may assist in the early identification and susceptibility testing of GNB. Further research is necessary to develop appropriate methods for GPC.

INTRODUCTION: Epidemiological data on the prevalence of extended-spectrum β-lactamases (ESBLs) are scarce in Brazil despite the fact that these data are essential for empirical treatment and control measures. The objective of this study was to evaluate the prevalence of different ESBLs by type and distribution in a tertiary hospital in southern Brazil. METHODS: We evaluated 1,827 enterobacterial isolates between August 2003 and March 2008 isolated from patients at a tertiary hospital. Samples were identified using a Vitek automated system and were confirmed by biochemical testing. The identified ESBL strains were characterized by phenotypic methods, polymerase chain reaction (PCR), and sequencing. Genetic similarities were evaluated by pulsed-field gel electrophoresis. RESULTS: It was 390 (21.3%) ESBL-producing strains, which expressed the ESBLs CTX-M (292), SHV (84), CTX and SHV (10), TEM (2), and PER (2). CONCLUSIONS: The prevalence of ESBL-expressing strains was high, especially in Klebsiella pneumoniae and Enterobacter spp. CTX-M was the predominant type of ESBL observed, and its genetic variability indicates a polyclonal distribution.

Este estudo verificou o perfil de resistência aos antimicrobianos entre isolados de Escherichia coli de frangos de corte de criação intensiva e de subsistência e dos respectivos tratadores e a similaridade genotípica entre isolados de E.coli de frangos de corte de criação intensiva e isolados de E. coli de tratadores de frangos de criação intensiva pela técnica de Eletroforese em Gel de Campo Pulsado (PFGE). 60 amostras de fezes de frangos de criação intensiva, 60 de frangos de corte de criação de subsistência (caipira) e 20 amostras dos tratadores de frangos de criação intensiva e 20 de tratadores de frangos de criação de subsistência. E. coli foram isoladas, identificadas e submetidas ao teste de suscetibilidade a 12 antimicrobianos. Pela PFGE foram analisados 24 isolados de E. coli de frangos de corte de criação intensiva e oito de tratadores. Em isolados E. coli de frangos de criação intensiva a resistência para a ampicilina foi de 100%, cefotaxima 43%, ceftriaxona 48%, ácido nalidíxico 62%, enrofloxacina 23%, ciprofloxacina 23%, tetraciclina 83% e 45% para trimetoprim-sulfametoxazol. Nos isolados de frangos de criação de subsistência foi de 20%, 0%, 0%, 5%, 2%, 4%, 33% e 8%, respectivamente. Resistência à fosfomicina e à nitrofurantoína foi encontrada em isolados de frangos de criação de subsistência. Em isolados de E. coli de tratadores de frangos de corte de criação intensiva a resistência para ampicilina foi de 60%, para ciprofloxacina 25% e para tetraciclina 45%, enquanto nos tratadores de subsistência foram de 20%, 5% e 30%, respectivamente. Isolados de E. coli de frangos em criação de subsistência apresentaram 46,6%(28/60) de suscetibilidade a todos os antimicrobianos testados enquanto que na criação intensiva 81%(49/60) foram multirresistentes. Sete clusters de isolados de E. coli de frangos de diferentes aviários apresentaram similaridade acima de 80%, e dois destes foram superiores a 95%. Três clusters de isolados de frangos e de tratadores apresentaram similaridade superior a 80%. Somente um destes clusters foi de isolado de tratador e de frango do mesmo aviário.

This study examined the profile of antimicrobial resistance among isolates of Escherichia coli from poultry intensive farming and free-range systems and their farmers. For technique of Gel Electrophoresis Pulsed Field (PFGE) examined the similarity between isolates from poultry intensive farming and their farmers. From 60 samples of poultry feces from intensive farming systems, 60 of free-range extensive systems and 20 of farmers of each segment, the E. coli was isolated and submitted to the test of susceptability to 12 antimicrobials. 24 isolates of E. coli of poultry from intensive farming systems and eight E. coli isolates from farmers poultry intensive farming were analyzed via technique of PFGE. In intensive farming systems poultry, 100% resistence to ampicillin was verified, 43% to cefotaxime, 48% to ceftriaxone, 62% to nalidixic acid, 23% to enrofloxacin, 23% to ciprofloxacin, 83% to tetracycline and 45% to trimetroprim-sulfametoxazol. In the strains of free-range extensive systems, resistance was 20%, 0%, 0%, 5%, 2%, 4%, 33% and 8%, respectively. Resistance to fosfomycin and to nitrofuratoin was found in isolates of poultry from free-range extensive systems. In farmers from intensive farming systems, the resistance to ampicillin was 60%, 25% to ciprofloxacin and 45% to tetracycline, whereas in farmers from free-range extensive systems, it was 20%, 5% and 30%, respectively. In the isolates of E. coli poultry from free-range extensive systems, 46.6% (28/60) presented themselves as susceptible to all tested antimicrobials in comparison to intensive farming systems in which 81,6% (49/60) were multiresistant. Seven clusters of isolates from poultry showed similarity above 80%. Out of these, two clusters of isolates of poultry from different aviaries presented superior clonality to 95%. Furthermore three clusters isolates of poultry and farmers showed similarity greater than 80%, but only one cluster isolate of attendant and poultry were from the same aviary.

Prevalence of H. pylori infection was determined using cultures of gastric biopsy samples of patients attended at the academic hospital of the Federal University of Paraná, Curitiba, Paraná, Brazil. Molecular methods were used to characterize the cagA and vacA genes from bacterial isolates associated with different diseases presented by patients. Out of a total of 81, forty-two gastric biopsy samples tested were positive for H. pylori, with a prevalence of 51.9%. No significant difference was found with regard to the gender (p=0.793) and age (p=0.183) of the patients. Genotype s1m1 vacA gene was found in 67% of the cases of peptic ulcer investigated (p=1.0), despite the limited number of patients with this disease (n=3). A correlation between the presence of less virulent strains (s2m2) and reflux esophagitis was found in the majority of the cases (45%), but without statistical significance. An association between the prevalence of cagA gene, found in 92% of isolates, and peptic ulcer was not observed (p=1.0), suggesting that this gene cannot be considered a specific marker of severity in our environment. The results reinforce the importance of conducting regional studies and the need to characterize H. pylori virulence genes associated with different diseases.

The objective of this study was to evaluate the susceptibility to cefepime of a large group of ESBL- producing enterobacteria recently isolated in a Brazilian teaching hospital . The study included 280 strains of ESBL-producing enterobacteria, isolated between 2005 and 2008. The presence of the genes blaCTX-M, blaTEM and blaSHV was determined by PCR and confirmed by nucleotide sequencing. Susceptibility testing for cefepime was performed by disc-diffusion, agar dilution method and E-test®. Among the isolates, 34 (12.1%) presented a cefepime inhibition zone > 21 and MIC < 8 mg/L by agar dilution and E-strip methods. The use of cefepime for the treatment of infections caused by ESBL-producing bacteria has been controversial. Some studies of PD/PK show the probability of achieving the required PD parameters for cefepime, when the MICs were < 8 mg/L, whereas others have reported therapeutic failure with the same MIC. Additional data is essential to come to terms about the report and treatment with cefepime in ESBL-producing organisms especially when these microorganisms are isolated from sterile sites and from critically ill patients.

The antibacterial activity of plant extracts obtained from Bixa orellana L., Chamomilla recutita L., Ilex paraguariensis A. St.-Hil., Malva sylvestris L., Plantago major L. and Rheum rhaponticum L. has been evaluated against two reference strains and eleven clinical isolates of Helicobacter pylori. All the plant species chosen are used in popular Brazilian cuisine and folk medicine in the treatment of gastrointestinal disorders. Initial screening was made by the disk diffusion test and then minimum inhibitory concentration was determined by the agar dilution method. The results presented in this work demonstrated that among the plant preparations analyzed, B. orellana L., C. recutita L., I. paraguariensis A. St.-Hil. and M. sylvestris L. were capable of inhibiting the in vitro growth of H. pylori.