Bone mineral density (BMD), micro-architecture estimation (TBS) and vertebral fracture assessment (VFA) extracted from a single DXA device in combination with clinical risk factors improve significantly the identification of women at high risk of fracture

Introduction: Osteoporosis (OP) is a systemic skeletal disease characterized by a low bone mineral density (BMD) and a micro-architectural (MA) deterioration. Clinical risk factors (CRF) are often used as a MA approximation. MA is yet evaluable in daily practice by the Trabecular Bone Score (TBS) measure. TBS is a novel grey-level texture measurement reflecting bone micro-architecture based on the use of experimental variograms of 2D projection images. TBS is very simple to obtain, by reanalyzing a lumbar DXA-scan. TBS has proven to have diagnosis and prognosis value, partially independent of CRF and BMD. The aim of the OsteoLaus cohort is to combine in daily practice the CRF and the information given by DXA (BMD, TBS and vertebral fracture assessment (VFA)) to better identify women at high fracture risk. Method: The OsteoLaus cohort (1400 women 50 to 80 years living in Lausanne, Switzerland) started in 2010. This study is derived from the cohort COLAUS who started in Lausanne in 2003. The main goals of COLAUS is to obtain information on the epidemiology and genetic determinants of cardiovascular risk in 6700 men and women. CRF for OP, bone ultrasound of the heel, lumbar spine and hip BMD, VFA by DXA and MA evaluation by TBS are recorded in OsteoLaus. Preliminary results are reported. Results: We included 631 women: mean age 67.4±6.7 y, BMI 26.1±4.6, mean lumbar spine BMD 0.943±0.168 (T-score -1.4 SD), TBS 1.271±0.103. As expected, correlation between BMD and site matched TBS is low (r2=0.16). Prevalence of VFx grade 2/3, major OP Fx and all OP Fx is 8.4%, 17.0% and 26.0% respectively. Age- and BMI-adjusted ORs (per SD decrease) are 1.8 (1.2- 2.5), 1.6 (1.2-2.1), 1.3 (1.1-1.6) for BMD for the different categories of fractures and 2.0 (1.4-3.0), 1.9 (1.4-2.5), 1.4 (1.1-1.7) for TBS respectively. Only 32 to 37% of women with OP Fx have a BMD < -2.5 SD or a TBS < 1.200. If we combine a BMD < -2.5 SD or a TBS < 1.200, 54 to 60% of women with an osteoporotic Fx are identified. Conclusion: As in the already published studies, these preliminary results confirm the partial independence between BMD and TBS. More importantly, a combination of TBS subsequent to BMD increases significantly the identification of women with prevalent OP Fx which would have been miss-classified by BMD alone. For the first time we are able to have complementary information about fracture (VFA), density (BMD), micro- and macro architecture (TBS & HAS) from a simple, low ionizing radiation and cheap device: DXA. Such complementary information is very useful for the patient in the daily practice and moreover will likely have an impact on cost effectiveness analysis.

Evaluation des facteurs de risque cliniques et des données de la DXA (DMO, VFA, TBS) pour la prédiction du risque fracturaire. L'étude de la cohorte OséoLaus.

Introduction. - L'ostéoporose est caractérisée par une diminution dela densité minérale osseuse (DMO) et une détérioration de lamicroarchitecture osseuse (MO). En routine clinique, l'appréciationde la MO se fait de façon approximative en utilisant les facteurs derisque clinique (FRC). Il est maintenant possible d'estimer de façonsimple la MO en mesurant le Trabecular Bone Score (TBS) par réanalysed'une image DXA lombaire. TBS a une valeur diagnostiqueet pronostique indépendante des FRC et de la DMO. Le but de lacohorte lausannoise OstéoLaus est de combiner des éléments facilesà obtenir en routine clinique, à savoir les FRC et les éléments issusde la DXA (DMO, TBS, VFA) pour évaluer le risque fracturaire defaçon transversale puis prospective.Patients et Méthodes. - Nous avons constitué une cohorte d'environ1400 femmes entre 50 et 80 ans de la région lausannoise enrôléedepuis 7 ans dans une vaste cohorte (CoLaus, 6 700 participants)évaluant les facteurs génétiques et phénotypiques de maladies fréquentescardiovasculaires et psychiatriques. Le taux de participationà Ostéolaus est > 85%. Ces femmes sont vues entre mars 2010et décembre 2012. Elles passent un questionnaire, un ultrasonosseux du talon, une DXA de la colonne et de la hanche et une évaluationpar VFA (selon la méthode semi-quantitative de Genant) etle TBS. Nous rapportons les résultats préliminaires sur 631 participantes.Les données concernant les fractures (fx) vertébrales ne distinguentpas les origines traumatiques ou non.Résultats. - L'âge est de 67,4 ± 6,7 ans, l'IMC de 26.1 ± 4,6. Les donnéesbrutes de la colonne lombaire montrent une DMO à 0,943 ±0,168 (T-score -1,4 DS) et un TBS à 1,271 ± 0,103. La corrélationentre DMO et TBS est faible avec r2 = 0,16. La prévalence des fx vertébralesgrade 2/3, des fx ostéoporotiques majeures, et de toutes lesfx ostéoporotiques est de 8,4 %, 17,0 % et 26.0 % respectivement. LesORs (par diminution d'une déviation standard) ajustés pour l'âge etl'IMC sont pour la DMO de 1,8 (1,2-2,5), 1,6 (1,2-2,1), 1,3 (1,1-1,6),et pour TBS de 2,0 (1,4-3,0), 1,9 (1,4-2,5), 1.4 (1,1-1,7), respectivement.Le taux de fx avec DMO <þ- 2,5 DS se situe entre 35 et 37 %et le taux de fx avec un TBS < 1.200 entre 37 et 44 %. Par contre cetaux augmente entre 54 et 60 % si l'on combine une DMO < - 2,5 DSou un TBS < 1,200.Conclusion. - Ces données préliminaires confirment la faible corrélationentre la DMO et le TBS. Ajouter le TBS à la DMO permetd'augmenter significativement le nombre de participantes avec unefx ostéoporotique prévalente. Une mesure simple et peu irradiantepar DXA offre ainsi 3 informations complémentaires et pertinentespour la routine clinique : la DMO, la recherche des fractures vertébraleset le TBS.

Comment améliorer la reproductibilité de lecture des VFA en dépistage clinique? la cohorte OsteoLaus.

Introduction. - Les fractures ostéoporotiques entrainent une morbi-mortalité et des coûts économiques et humains grandissants. Des campagnes de dépistage se mettent en place associant questionnaire et DXA afin d'évaluer le risque fracturaire individuel et populationnel. La découverte fortuite d'une fracture vertébrale (VF), rendue possible par la réalisation d'une morphométrie vertébrale de profil (VFA par DXA) de D4 à L4, peut changer le diagnostic et le pronostic. Néanmoins sa reproductibilité de lecture est peu élevée, surtout sur le rachis dorsal et les fractures de grade 1 [1]. L'IOF/ISCD a proposé un guide pour en améliorer la lecture. Nous avons mesuré la reproductibilité de lecture des VFA avant et après application de ce guide sur une cohorte Suisse de dépistage de l'ostéoporose. Patients et méthodes. - 360 VFA (Hologic Delphi) issus aléatoirement de la cohorte OstéoLaus (femmes > 50 ans) ont été lus par 2 lecteurs indépendants avant et après application du guide de lecture. Il comporte des règles de condition de lecture (luminosité, contraste sur l'écran) et des étapes de lecture systématisées. La reproductibilité a été évaluée par le test de kappa sur : la lisibilité de chaque vertèbre, l'existence ou non d'une VF, son grade (1, 2 ou 3 selon Genant). Nous avons utilisé le Kappa de Cohen avec une technique de bootstrap pour les comparaisons avant/après sur des données corrélées. Résultats. - L'accord entre les lecteurs est élevé et s'améliore après application du guide de lecture (tableau). Le kappa de Cohen est modéré à bon selon Landis et Koch (0,4-0,7). La reproductibilité sur les grades est améliorée en regroupant les grades 0/1 et 2/3, mais pas par le guide de lecture. Conclusion. - L'utilisation du guide de lecture des VFA IOF/ISCD améliore la reproductibilité sur la lisibilité des vertèbres, la détection des VF, mais pas la classification du grade selon Genant. Ceci est principalement expliqué par le fait que le kappa de Cohen donne beaucoup d'importance à la distribution des données, qui devient asymétrique lorsque l'événement est rare. Le kappa uniforme [2] serait mieux adapté dans cette situation. Une réanalyse est en cours.

Bone mineral density (BMD), micro-architecture estimation (TBS) and vertebral fracture assessment (VFA) extracted from a single DXA device in combination with clinical risk factors improve significantly the identification of women at high risk of fracture.

Osteoporosis (OP) is a systemic skeletal disease characterized by a low bone mineral density (BMD) and a micro-architectural (MA) deterioration. Clinical risk factors (CRF) are often used as a MA approximation. MA is yet evaluable in daily practice by the trabecular bone score (TBS) measure. TBS is very simple to obtain, by reanalyzing a lumbar DXA-scan. TBS has proven to have diagnosis and prognosis values, partially independent of CRF and BMD. The aim of the OsteoLaus cohort is to combine in daily practice the CRF and the information given by DXA (BMD, TBS and vertebral fracture assessment (VFA)) to better identify women at high fracture risk. The OsteoLaus cohort (1400 women 50 to 80 years living in Lausanne, Switzerland) started in 2010. This study is derived from the cohort COLAUS who started in Lausanne in 2003. The main goal of COLAUS is to obtain information on the epidemiology and genetic determinants of cardiovascular risk in 6700 men and women. CRF for OP, bone ultrasound of the heel, lumbar spine and hip BMD, VFA by DXA and MA evaluation by TBS are recorded in OsteoLaus. Preliminary results are reported. We included 631 women: mean age 67.4 ± 6.7 years, BMI 26.1 ± 4.6, mean lumbar spine BMD 0.943 ± 0.168 (T-score − 1.4 SD), and TBS 1.271 ± 0.103. As expected, correlation between BMD and site matched TBS is low (r2 = 0.16). Prevalence of VFx grade 2/3, major OP Fx and all OP Fx is 8.4%, 17.0% and 26.0% respectively. Age- and BMI-adjusted ORs (per SD decrease) are 1.8 (1.2-2.5), 1.6 (1.2-2.1), and 1.3 (1.1-1.6) for BMD for the different categories of fractures and 2.0 (1.4-3.0), 1.9 (1.4-2.5), and 1.4 (1.1-1.7) for TBS respectively. Only 32 to 37% of women with OP Fx have a BMD < − 2.5 SD or a TBS < 1.200. If we combine a BMD < − 2.5 SD or a TBS < 1.200, 54 to 60% of women with an osteoporotic Fx are identified. As in the already published studies, these preliminary results confirm the partial independence between BMD and TBS. More importantly, a combination of TBS subsequent to BMD increases significantly the identification of women with prevalent OP Fx which would have been misclassified by BMD alone. For the first time we are able to have complementary information about fracture (VFA), density (BMD), micro- and macro architecture (TBS and HAS) from a simple, low ionizing radiation and cheap device: DXA. Such complementary information is very useful for the patient in the daily practice and moreover will likely have an impact on cost effectiveness analysis.

Assessing the impact of ammonia content in VFA-rich streams on the PHA-storing MMC acclimatization and the PHA production stage

The use of environmentally friendly products increased the interest in renewable resources as alternatives to petrochemical products. Polyhydroxyalkanoates (PHAs) are examples of such promising products, as they are biodegradable polymers with numerous potential applications. PHA production approach consists of using an open mixed microbial culture (MMC) and inexpensive feedstocks (waste or industry byproducts feedstock). The PHA process generally comprises three stages: (1) acidogenic fermentation (AF) stage (conversion of organic carbon into fermentation products); (2) culture selection stage (enrichment in PHA-storing organisms by applying Feast and Famine regime); and (3) PHA production stage (PHA accumulation up to the culture’s maximum capacity). AF of protein-rich residues results in ammonia-rich fermented streams, which can be presented as a challenge for the PHA production stage. The presence of ammonia during this stage may induce organisms to grow instead of producing PHAs. For this reason, the assessment of the effect of a high content of ammonia on PHA production it is the utmost importance. The main goal of the current project is to select a MMC enriched in PHA-accumulating organisms in conditions of high ammonia content and to evaluate the effects of ammonia presence during PHA accumulation. The culture was selected applying the Feast & Famine strategy, and fed, firstly, using a synthetic mixture of VFAs and later using a fermented stream obtained from the fermentation of protein-rich raw materials. The selected culture could accumulate up to 24% PHA per VSS with the synthetic mixture of VFAs and up to 29% for the real fermented stream. The PHA accumulation resulted in different production in the presence and absence of ammonia. Regarding to the synthetic feed, 59%wt. PHA (VSS basis) in the absence of ammonia, and 55%wt. (VSS basis) in the presence, were obtained. For the real feed, the PHA content was about 40%wt. (VSS basis) in both reactors.

Efeitos de dietas contendo Leucaena leucocephala e Saccharomyces cerevisiae sobre a fermentação ruminal e a emissão de gás metano em bovinos

Este trabalho foi realizado com o objetivo de avaliar os efeitos do uso de leucena e levedura em dietas para bovinos sobre o metabolismo ruminal, incluindo o pH e as produções de ácido graxos voláteis (AGV), amônia e gás metano. Quatro bovinos machos com 800 kg e fistulados no rúmen foram mantidos em quadrado latino 4 × 4, em arranjo fatorial 2 × 2, composto de dois níveis de leucena (20 e 50% MS) e feno de capim coast-cross na presença ou ausência de levedura. Não houve influência das dietas nos valores médios de pH (média 6,82) e nas concentrações de amônia no rúmen, que variaram de 18 a 21 mg/100 mL. Houve interação entre níveis de leucena e levedura na concentração total de AGV. As dietas não diferiram quanto à concentração de ácido acético, mas os animais alimentados com a dieta com 50% de leucena e contendo levedura apresentaram maiores concentrações médias de ácido propiônico (média 19,14 mM). A emissão de metano reduziu em12,3% em relação à mesma dieta sem levedura e em 17,2% quando os animais foram alimentados com 20% de leucena com levedura. Verificou-se efeito associativo de leucena, quando fornecida em alto nível na dieta (50% MS), e levedura na redução da emissão de metano e na melhoria no padrão de fermentação no rúmen, o que pode reduzir as perdas de energia e melhorar eficiência energética do animal.

Simplified Mathematical Model for an Anaerobic Sequencing Batch Biofilm Reactor Treating Lipid-Rich Wastewater Subject to Rising Organic Loading Rates

This study proposes a simplified mathematical model to describe the processes occurring in an anaerobic sequencing batch biofilm reactor (ASBBR) treating lipid-rich wastewater. The reactor, subjected to rising organic loading rates, contained biomass immobilized cubic polyurethane foam matrices, and was operated at 32 degrees C +/- 2 degrees C, using 24-h batch cycles. In the adaptation period, the reactor was fed with synthetic substrate for 46 days and was operated without agitation. Whereas agitation was raised to 500 rpm, the organic loading rate (OLR) rose from 0.3 g chemical oxygen demand (COD) . L(-1) . day(-1) to 1.2 g COD . L(-1) . day(-1). The ASBBR was fed fat-rich wastewater (dairy wastewater), in an operation period lasting for 116 days, during which four operational conditions (OCs) were tested: 1.1 +/- 0.2 g COD . L(-1) . day(-1) (OC1), 4.5 +/- 0.4 g COD . L(-1) . day(-1) (OC2), 8.0 +/- 0.8 g COD . L(-1) . day(-1) (OC3), and 12.1 +/- 2.4 g COD . L(-1) . day(-1) (OC4). The bicarbonate alkalinity (BA)/COD supplementation ratio was 1:1 at OC1, 1:2 at OC2, and 1:3 at OC3 and OC4. Total COD removal efficiencies were higher than 90%, with a constant production of bicarbonate alkalinity, in all OCs tested. After the process reached stability, temporal profiles of substrate consumption were obtained. Based on these experimental data a simplified first-order model was fit, making possible the inference of kinetic parameters. A simplified mathematical model correlating soluble COD with volatile fatty acids (VFA) was also proposed, and through it the consumption rates of intermediate products as propionic and acetic acid were inferred. Results showed that the microbial consortium worked properly and high efficiencies were obtained, even with high initial substrate concentrations, which led to the accumulation of intermediate metabolites and caused low specific consumption rates.

Vitamin D insufficiency: A risk factor to vertebral fractures in community-dwelling elderly women

Objective:To determine the risk factors for the presence of moderate/severe vertebral fracture, specifically 25-hydroxyvitamin D (25-OHD). Study design: Cross-sectional study conducted for 2 years in the city of Sao Paulo, Brazil including community-dwelling elderly women. Methods: Bone mineral density (BMD), serum 25-OHD, intact parathyroid hormone (iPTH), calcium and estimated glomerular filtration rate (eGFR) were examined in 226 women without vertebral fractures (NO FRACTURE group) and 189 women with at least one moderate/severe vertebral fracture (FRACTURE group). Vertebral fracture assessment (VFA) was evaluated using both the Genant semiquantitative (SQ) approach and morphometry. Results: Patients in the NO FRACTURE group had lower age, increased height, higher calcium intake, and higher BMD compared to those patients in the FRACTURE group (p < 0.05). Of interest, serum levels of 25-OHD in the NO FRACTURE group were higher than those observed in the FRACTURE group (51.73 nmol/L vs. 42.31 nmol/L, p < 0.001). Reinforcing this finding, vitamin D insufficiency (25-OHD < 75 nmol/L) was observed less in the NO FRACTURE group (82.3% vs. 93.65%, p = 0.001). After adjustment for significant variables within the patient population (age, height, race, calcium intake, 25-OHD, eGFR and sites BMD), the logistic-regression analyses revealed that age (OR = 1.09, 95% Cl 1.04-1.14, p < 0.001) femoral neck BMD (OR = 0.7, 95% CI 0.6-0.82, p < 0.001) and 25-OHD <75 nmol/L (OR = 2.38, 95% CI 1.17-4.8, p = 0.016) remains a significant factor for vertebral fracture. Conclusion: Vitamin D insufficiency is a contributing factor for moderate/severe vertebral fractures. This result emphasizes the importance of including this modifiable risk factor in the evaluation of elderly women. (C) 2009 Elsevier Ireland Ltd. All rights reserved.

Relation between visceral fat and coronary artery disease evaluated by multidetector computed tomography

Visceral abdominal fat has been associated to cardiovascular risk factors and coronary artery disease (CAD). Computed tomography (CT) coronary angiography is an emerging technology allowing detection of both obstructive and nonobstructive CAD adding information to clinical risk strati. cation. The aim of this study was to evaluate the association between CAD and adiposity measurements assessed clinically and by CT. We prospectively evaluated 125 consecutive subjects (57% men, age 56.0 +/- 12 years) referred to perform CT angiography. Clinical and laboratory variables were determined and CT angiography and abdominal CT were performed in a 64-slice scanner. CAD was defined as any plaque calcified or not detected by CT angiography. Visceral and subcutaneous adiposity areas were determined at different intervertebral levels. CT angiography detected CAD in 70 (56%) subjects, and no association was found with usual anthropometric adiposity measurements (waist and hip circumferences and body mass index). Otherwise, CT visceral fat areas (VFA) were significantly related to CAD. VFA T12-L1 values >= 145 cm(2) had an odds ratio of 2.85 (95% CI 1.30-6.26) and VFA L4-L5 >= 150 cm(2) had a 2.87-fold (95% CI 1.31-6.30) CAD risk. The multivariate analysis determined age and VFA T12-L1 as the only independent variables associated to CAD. Visceral fat assessed by CT is an independent marker of CAD determined by CT angiography. (C) 2009 Elsevier Ireland Ltd. All rights reserved.

Verbal fluency in the detection of mild cognitive impairment and Alzheimer`s disease among Brazilian Portuguese speakers: the influence of education

Background: Verbal fluency (VF) tasks are simple and efficient clinical tools to detect executive dysfunction and lexico-semantic impairment. VF tasks are widely used in patients with suspected dementia, but their accuracy for detection of mild cognitive impairment (MCI) is still under investigation. Schooling in particular may influence the subject`s performance. The aim of this study was to compare the accuracy of two semantic categories (animals and fruits) in discriminating controls, MCI patients and Alzheimer`s disease (AD) patients. Methods: 178 subjects, comprising 70 controls (CG), 70 MCI patients and 38 AD patients, were tested on two semantic VF tasks. The sample was divided into two schooling groups: those with 4-8 years of education and those with 9 or more years. Results: Both VF tasks - animal fluency (VFa) and fruits fluency (VFf) - adequately discriminated CG from AD in the total sample (AUC = 0.88 +/- 0.03, p < 0.0001) and in both education groups, and high educated MCI from AD (VFa: AUC = 0.82 +/- 0.05, p < 0.0001; VFf: AUC = 0.85 +/- 0.05, p < 0.0001). Both tasks were moderately accurate in discriminating CG from MCI (VFa: AUC = 0.68 +/- 0.04, p < 0.0001 - VFf:AUC = 0.73 +/- 0.04, p < 0.0001) regardless of the schooling level, and MCI from AD in the total sample (VFa: AUC = 0.74 +/- 0.05, p < 0.0001; VFf: AUC = 0.76 +/- 0.05, p < 0.0001). Neither of the two tasks differentiated low educated MCI from AD. In the total sample, fruits fluency best discriminated CG from MCI and MCI from AD; a combination of the two improved the discrimination between CG and AD. Conclusions: Both categories were similar in discriminating CG from AD; the combination of both categories improved the accuracy for this distinction. Both tasks were less accurate in discriminating CG from MCI, and MCI from AD.

The IWA Anaerobic Digestion Model No 1 (ADM1)

The IWA Anaerobic Digestion Modelling Task Group was established in 1997 at the 8th World Congress on,Anaerobic Digestion (Sendai, Japan) with the goal of developing a generalised anaerobic digestion model. The structured model includes multiple steps describing biochemical as well as physicochemical processes. The biochemical steps include disintegration from homogeneous particulates to carbohydrates, proteins and lipids; extracellular hydrolysis of these particulate substrates to sugars, amino acids, and long chain fatty acids (LCFA), respectively; acidogenesis from sugars and amino acids to volatile fatty acids (VFAs) and hydrogen; acetogenesis of LCFA and VFAs to acetate; and separate methanogenesis steps from acetate and hydrogen/CO2. The physico-chemical equations describe ion association and dissociation, and gas-liquid transfer. Implemented as a differential and algebraic equation (DAE) set, there are 26 dynamic state concentration variables, and 8 implicit algebraic variables per reactor vessel or element. Implemented as differential equations (DE) only, there are 32 dynamic concentration state variables.

Analysis of the microbial community structure and function of a laboratory scale enhanced biological phosphorus removal reactor

A laboratory scale sequencing batch reactor (SBR) operating for enhanced biological phosphorus removal (EBPR) and fed with a mixture of volatile fatty acids (VFAs) showed stable and efficient EBPR capacity over a four-year-period. Phosphorus (P), poly-beta-hydroxyalkanoate (PHA) and glycogen cycling consistent with classical anaerobic/aerobic EBPR were demonstrated with the order of anaerobic VFA uptake being propionate, acetate then butyrate. The SBR was operated without pH control and 63.67+/-13.86 mg P l(-1) was released anaerobically. The P% of the sludge fluctuated between 6% and 10% over the operating period (average of 8.04+/-1.31%). Four main morphological types of floc-forming bacteria were observed in the sludge during one year of in-tensive microscopic observation. Two of them were mainly responsible for anaerobic/aerobic P and PHA transformations. Fluorescence in situ hybridization (FISH) and post-FISH chemical staining for intracellular polyphosphate and PHA were used to determine that 'Candidatus Accumulibacter phosphatis' was the most abundant polyphosphate accumulating organism (PAO), forming large clusters of coccobacilli (1.0-1.5 mum) and comprising 53% of the sludge bacteria. Also by these methods, large coccobacillus-shaped gammaproteobacteria (2.5-3.5 mum) from a recently described novel cluster were glycogen-accumulating organisms (GAOs) comprising 13% of the bacteria. Tetrad-forming organisms (TFOs) consistent with the 'G bacterium' morphotype were alphaproteobacteria , but not Amaricoccus spp., and comprised 25% of all bacteria. According to chemical staining, TFOs were occasionally able to store PHA anaerobically and utilize it aerobically.

The effect of volatile fatty acids in acidified fermented piggery effluent on shiga-toxigenic and non-toxic resident strains of Escherichia coli

Aims: To examine the effects of acidified acidogenically fermented piggery effluent containing Volatile Fatty Acids (VFA) on shiga-toxigenic and resident strains of Escherichia coli (E. coli) as part of the development of a waste treatment process. Methods and Results: Four shiga-toxigenic E. coli strains (O157:H7, 091.H-, 0111.H-, and 0123.H-) and four non-toxic resident enzootic strains were all killed by 3 h treatment with fermented piggery effluent liquor (153 mmol l(-1) total VFA) at pH 4.3. The shiga-toxigenic strains showed greater sensitivity after 1 h of treatment. The fermented liquor at pH 6.8 was not inhibitory. Conclusions: The shiga-toxigenic strains were no more resistant to the toxic effects of VFA than the non-toxic strains tested. Significance and Impact of the Study: Shiga-toxigenic strains and resident enzootic non-toxigenic strains are equally susceptible to inactivation by this waste treatment process and by acidified VFA in general.