Antimicrobial activities of six essential oils commonly used as condiments in Brazil against Clostridium perfringens

Abstract Despite recent advances in food production technology, food-borne diseases (FBD) remain a challenging public health concern. In several countries, including Brazil, Clostridium perfringens is among the five main causative agents of food-borne diseases. The present study determines antimicrobial activities of essential oils of six condiments commonly used in Brazil, viz., Ocimum basilicum L. (basil), Rosmarinus officinalis L. (rosemary), Origanum majorana L. (marjoram), Mentha × piperita L. var. Piperita (peppermint), Thymus vulgaris L. (thyme) and Pimpinella anisum L. (anise) against C. perfringens strain A. Chemical compositions of the oils were determined by GC–MS (gas chromatography–mass spectrometry). The identities of the isolated compounds were established from the respective Kováts indices, and a comparison of mass spectral data was made with those reported earlier. The antibacterial activity was assessed from minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) using the microdilution method. Minimum inhibitory concentration values were 1.25 mg mL-1 for thyme, 5.0 mg mL-1 for basil and marjoram, and 10 mg mL-1 for rosemary, peppermint and anise. All oils showed bactericidal activity at their minimum inhibitory concentration, except anise oil, which was only bacteriostatic. The use of essential oils from these common spices might serve as an alternative to the use of chemical preservatives in the control and inactivation of pathogens in commercially produced food systems.

Antimicrobial activities of six essential oils commonly used as condiments in Brazil against Clostridium perfringens.

Despite recent advances in food production technology, food-borne diseases (FBD) remain a challenging public health concern. In several countries, including Brazil, Clostridium perfringens is among the five main causative agents of food-borne diseases. The present study determines antimicrobial activities of essential oils of six condiments commonly used in Brazil, viz., Ocimum basilicum L. (basil), Rosmarinus officinalis L. (rosemary), Origanum majorana L. (marjoram), Mentha × piperita L. var. Piperita (peppermint), Thymus vulgaris L. (thyme) and Pimpinella anisum L. (anise) against C. perfringens strain A. Chemical compositions of the oils were determined by GC-MS (gas chromatography-mass spectrometry). The identities of the isolated compounds were established from the respective Kováts indices, and a comparison of mass spectral data was made with those reported earlier. The antibacterial activity was assessed from minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) using the microdilution method. Minimum inhibitory concentration values were 1.25mgmL(-1) for thyme, 5.0mgmL(-1) for basil and marjoram, and 10mgmL(-1) for rosemary, peppermint and anise. All oils showed bactericidal activity at their minimum inhibitory concentration, except anise oil, which was only bacteriostatic. The use of essential oils from these common spices might serve as an alternative to the use of chemical preservatives in the control and inactivation of pathogens in commercially produced food systems.

Prevalência e perfil de resistência de Escherichia coli em uroculturas positivas no município de Triunfo/RS / Prevalence and resistance profile of Escherichia coli in positive urocultures in Triunfo, RS

Introdução: As infecções do trato urinário (ITU) são um importante problema de saúde pública na atualidade, e sua prevalência varia com o sexo e a idade dos pacientes. É bastante comum que o tratamento empírico seja instituído antes da identificação do agente etiológico, gerando um consumo inadequado de antibióticos. O principal agente etiológico dessas infecções é a Escherichia coli (E. coli), que apresenta importantes variações em relação à sua suscetibilidade aos antimicrobianos. O presente trabalho visa determinar a prevalência de patógenos responsáveis pelas infecções no trato urinário, relacionando-os com seu perfil de suscetibilidade aos antimicrobianos utilizados, no intuito de nortear o tratamento mais adequado. Métodos: Trata-se de um estudo transversal, retrospectivo das uroculturas realizadas no laboratório LAPEM, localizado na cidade de Triunfo/RS, no período compreendido entre julho/2010 e junho/2011. Foram selecionados todos os exames bacteriológicos de urina e realizada a verificação quanto à positividade e perfil de resistência para amostra que apresentava crescimento de E. coli, considerando os antimicrobianos de escolha, fluorquinolonas (ciprofloxacina, norfloxacina e levofloxacina), betalactâmicos (ampicilina, imipenem e ceftazidima), aminoglicosídeos (amicacina e gentamicina), ácido nalidíxico, sulfametoxazol/trimetroprim, nitrofurantoína e amoxicilina/ácido clavulânico. Resultados: No perí- odo, realizaram-se 1.274 uroculturas, com 28,89% das amostras demonstrando crescimento de algum agente bacteriano patogênico e 71,11% dos cultivos, sem crescimento algum. Das amostras positivas, 44,6% exibiam o crescimento de E. coli. Conclusão: Assim, os resultados obtidos neste estudo apresentam importância epidemiológica, visto que subsidiam a escolha mais adequada no manejo terapêutico do perfil regional de distribuição de patógenos.

Introduction: Urinary tract infections (UTI) are a major public health problem today, and their prevalence varies according to patient gender and age. It is quite common for empiric treatment to be instituted before identification of the etiologic agent, generating an inappropriate use of antibiotics. The main etiological agent of these infections is Escherichia coli (E. coli), which shows significant variations regarding its susceptibility to antibiotics. This study aims to determine the prevalence of pathogens responsible for urinary tract infections, relating them to their susceptibility profile to the antibiotics used, in order to guide the most appropriate treatment. Methods: This is a cross-sectional, retrospective study of urine cultures performed in the LAPEM laboratory, located in Triunfo, RS, from July 2010 to June 2011. We selected all urine bacteriological tests and checked their positivity and sample resistance profile showing growth of E. coli, considering the antimicrobials of choice, fluoroquinolones (ciprofloxacin, norfloxacin and levofloxacin), beta-lactams (ampicillin, imipenem and ceftazidime), aminoglycosides (amikacin and gentamicin), nalidixic acid, sulfamethoxazole/trimethoprim, nitrofurantoin and amoxicillin/ clavulanic acid. Results: During the study period, 1,274 urine cultures were performed, with 28.89% of samples showing growth of some pathogenic bacterial agent and 71.11% without any growth. From the positive samples, 44.6% exhibited growth of E. coli. Conclusions: The findings of this study have epidemiological significance, as they support the most appropriate choice in the therapeutic management of the regional profile of pathogen distribution.

High prevalence of Neisseria meningitidis hypervirulent lineages and emergence of W135:P1.5,2:ST-11 clone in Southern Brazil.

OBJECTIVES: The aim of this study was to characterize Neisseria meningitidis strains causing invasive disease in Rio Grande do Sul (RS), during 2003-2005, monitoring the occurrence of hypervirulent lineages, as well as to determine the diversity of PorA VR types for the corresponding isolates and clinical specimens. METHODS: Isolates and clinical specimens were characterized by MLST and PorA VR typing. RESULTS: This study demonstrated high prevalence of some hypervirulent lineages and emergence of new ones, including the emergence of lineages W135:P1.5,2:ST-11 complex, and C:P1.22,14-6:ST-103 complex. These lineages are probably responsible for the increasing incidence of serogroups C and W135, despite the overall decrease in serogroup B cases during the period. The most prevalent complex was serogroup B ST-32/ET-5 complex. The most prevalent PorA types found for serogroup B were P1.19,15, P1.7,16, and P1.18-1,3, representing a different distribution of PorA types compared to other states of Brazil. CONCLUSIONS: This study highlights the importance of monitoring each population, even within the same country. The different distribution of PorA VR types in RS has implications in vaccine design and efficacy. Detailed and accurate meningococcal characterization is an important element in studies of meningococcal epidemiology, population biology, and evolution and provides information for the design of control strategies.

Evaluation and improvement of real-time PCR assays targeting lytA, ply, and psaA genes for detection of pneumococcal DNA.

The accurate diagnosis of pneumococcal disease has frequently been hampered not only by the difficulties in obtaining isolates of the organism from patient specimens but also by the misidentification of pneumococcus-like viridans group streptococci (P-LVS) as Streptococcus pneumoniae. This is especially critical when the specimen comes from the respiratory tract. In this study, three novel real-time PCR assays designed for the detection of specific sequence regions of the lytA, ply, and psaA genes were developed (lytA-CDC, ply-CDC, and psaA, respectively). These assays showed high sensitivity (<10 copies for lytA-CDC and ply-CDC and an approximately twofold less sensitivity for psaA). Two additional real-time PCR assays for lytA and ply described previously for pneumococcal DNA detection were also evaluated. A panel of isolates consisting of 67 S. pneumoniae isolates (44 different serotypes and 3 nonencapsulated S. pneumoniae isolates from conjunctivitis outbreaks) and 104 nonpneumococcal isolates was used. The 67 S. pneumoniae isolates were reactive in all five assays. The new real-time detection assays targeting the lytA and psaA genes were the most specific for the detection of isolates confirmed to be S. pneumoniae, with lytA-CDC showing the greatest specificity. Both ply PCRs were positive for all isolates of S. pseudopneumoniae, along with 13 other isolates of other P-LVS isolates confirmed to be non-S. pneumoniae by DNA-DNA reassociation. Thus, the use of the ply gene for the detection of pneumococci can lead to false-positive reactions in the presence of P-LVS. The five assays were applied to 15 culture-positive cerebrospinal fluid specimens with 100% sensitivity; and serum and ear fluid specimens were also evaluated. Both the lytA-CDC and psaA assays, particularly the lytA-CDC assay, have improved specificities compared with those of currently available assays and should therefore be considered the assays of choice for the detection of pneumococcal DNA, particularly when upper respiratory P-LVS might be present in the clinical specimen.