Incidence of Antimicrobial Residues in Meat Using a Broad Spectrum Screening Strategy.

Aims: The aim of this paper was to assess the incidence of antimicrobial residues in market muscle samples from different animal species (bovine, ovine, poultry and porcine) using a new screening strategy. Methodology: 4849 samples were evaluated with a methodology that combines a broad spectrum microbial test (Explorer) and a specific test for quinolones detection (Equinox). Supplementary tests were performed to achieve additional information about the nature of antimicrobials in positive samples. Results: In a first step, 355 samples (7.3%) showed a positive result in Explorer and/or Equinox tests. The highest incidence of positive samples was obtained in poultry (9.7%) while the lowest rate was found in porcine samples (3.4%). Half of the positive screening samples (53%) showed also a positive result with supplementary tests indicating that tetracyclines, aminoglycosides sulphonamides and quinolones might be present in these samples. Aminoglycosides were the predominant residues in poultry while tetracyclines were more frequent in bovine and porcine samples. Sulphonamides were the main family of residues found in ovine. Conclusion: Our results suggest that the current strategies used for control of antimicrobial residues in muscle could not be adequate enough. In order to protect consumers from antibiotic exposition, it should be advisable to implement more efficient methods for the screening of antibiotic residues in muscle.

Research on antimicrobial residues activity in urine samples of hospitalized patients / Pesquisa da atividade de resíduos de antimicrobianos em amostras de urina de pacientes hospitalizados

Introduction: Urinary tract infection is quite frequent in a hospital environment, and the urine culture is the gold standard for diagnosis of this disease, because it allows bacterial identification and performing antimicrobial susceptibility testing. Culturenegative urine samples result of patients with strong suspicion of infection may occur due to the activity of antimicrobial residues, which can interfere with bacterial growth in vitro and produce false-negative results. Objective: Verify the occurrence of falsenegative urine cultures due to the presence of antimicrobial residues in samples of patients admitted to the Clinical Hospital of Paraná Federal University. Material and methods: A total of 188 urine samples from hospitalized patients were randomly selected, during the period from July to December 2012. All samples were evaluated on the result of the urine culture, bacteriuria, and research on residues of antimicrobial activity by manual and automated techniques. Results: 44 (23.4%) presented positive urine culture, 121 (64.4%) negative urine culture, and 23 (12.2%) presented growth of many species. In 14 samples, negative urine cultures associated with the presence of bacteria and were positive for the research on antimicrobial residues activity (RARA), were observed. Conclusion: Automated technique showed better performance when compared to manual technique, with sensitivity of 92.8% and 71.4%, respectively. The presence of antimicrobial residues may affect the recovery of bacteria in the urine, producing a false-negative result. .

Introdução: A infecção do trato urinário é bastante frequente em ambiente hospitalar, e a cultura de urina é padrão-ouro para o diagnóstico dessa doença, pois permite a identificação bacteriana e a realização do teste de suscetibilidade aos antimicrobianos. Amostras de urina de pacientes com forte suspeita de infecção que resultam em cultura negativa podem ocorrer devido à atividade de resíduos de antimicrobianos, os quais podem interferir no crescimento bacteriano in vitro e gerar resultados falso negativos. Objetivo: Verificar a ocorrência de culturas de urina falso negativas devido à presença de resíduos de antimicrobianos em amostras de pacientes internados no Hospital de Clínicas da Universidade Federal do Paraná. Material e métodos: Um total de 188 amostras de urina de pacientes internados foi selecionado aleatoriamente, durante o período de julho a dezembro de 2012. Todas as amostras foram avaliadas quanto ao resultado da cultura de urina, da bacteriúria e da pesquisa da atividade de resíduos de antimicrobianos por meio das técnicas manual e automatizada. Resultados: Quarenta e quatro (23,4%) apresentaram cultura de urina positiva, 121 (64,4%), cultura negativa e 23 (12,2%), crescimento de várias espécies. Em 14 amostras foi observada cultura negativa associada à presença de bactérias e pesquisa da atividade de resíduos de antimicrobianos (PRA) positiva. Conclusão: A técnica automatizada apresentou melhor desempenho quando comparada com a técnica manual, apresentando sensibilidade de 92,8% e 71,4%, respectivamente. A presença de resíduos de antimicrobianos pode comprometer a recuperação de bactérias na urina, gerando resultado falso negativo. .

Qualidade do leite de vacas criadas no sistema silvipastoril no Vale do Cauca, Colômbia / Milk quality indicators from cows bred on silvopastoral system in Cauca Valley, Colombia

O sistema silvipastoril caracteriza-se por aumentar a produção de leite, com maior número de vacas por hectare devido ao maior aporte de proteína na dieta. Neste sistema as vacas são alimentadas, além do pasto, de pequenas árvores e arbustos. O objetivo do presente estudo foi determinar os principais indicadores de qualidade do leite e agentes causais de mastite em vacas criadas em sistema silvipastoril. Foram avaliadas a composição (teor de gordura, proteína total, lactose, extrato seco, extrato seco desengordurado e nitrogênio uréico), contagem de células somáticas (CCS), contagem bacteriana total (CBT), ocorrência de mastite clínica e subclínica, isolamento microbiológico, perfil de sensibilidade bacteriana "in vitro" e detecção de resíduos antimicrobianos no leite produzido por 100 vacas, bem como do tanque de expansão e latões em propriedades do Vale do Cauca, Colômbia. Os teores médios dos principais constituintes do leite foram 3,24% de gordura, 3,27% de proteína total, 4,40% de lactose, 10,62% de extrato seco, 8,57% de extrato seco desengordurado e 15,82mg/dL de nitrogênio uréico, enquanto do tanque de expansão e latões foi 3,51% de gordura, 3,20% de proteína total, 4,34% de lactose, 11,72% de extrato seco, 8,47% de extrato seco desengordurado e 14,57mg/dL de nitrogênio uréico. A celularidade média dos quartos mamários e do tanque de expansão foi 141.252,75 CS/mL e 363.078,05 CS/mL respectivamente. A CBT média dos quartos mamários e do tanque de expansão foi 4.466,84 UFC/mL e 24.547,01 UFC/mL. Os principais micro-organismos isolados dos quartos mamários foram Corynebacterium bovis, Staphylococcus aureus, Staphylococcus hyicus, Staphylococcus spp., Streptococcus dysgalatiae, enquanto do tanque de expansão foram identificados Streptococcus spp., Enterobacter cloacae, Hafnia alveii, Streptococcus hemolítico e Streptococcus spp., com maior frequência. A presença de resíduos de antimicrobianos em leite de vacas e do tanque ou latão foi detectada em 30% e 86% das amostras, respectivamente. O sistema silvipastoril mostrou ser uma boa alternativa para produção de leite em vacas. No entanto, são necessários cuidados no tratamento mamário para evitar resíduos no leite e a análise de todos os parâmetros de qualidade para garantir um produto diferenciado.

The silvopastoral system is characterized by increasing the production of milk with a greater number of cows per hectare due to the higher amount of protein in the diet. In silvopastoral system cows are fed in addition to pasture, small trees and shrubs. The aim of this study was determinate the main indicators of milk quality and mastitis causal agents in cows bred on silvopastoral system. We evaluated the composition (fat, total protein, lactose, solids, dry extract, nonfat dry and urea nitrogen), somatic cell count (SCC), total bacterial count (TBC), occurrence of clinical and subclinical mastitis, microbiological isolation, in vitro antimicrobial sensitivity profile and detection of antimicrobial residues in milk produced by 100 cows raised in silvopastoral systems, as well as the bulk tank and churns in farms of Cauca Valley, Colombia. The concentration of the major constituents of milk were 3.24% fat, 3.27% total protein, 4.40% lactose, 10.62% dry extract, 8.57% nonfat dry and 15.82mg/dL urea nitrogen, while the bulk tank and churns was 3.51% fat, 3.20% total protein, 4.34% lactose, 11.72% dry extract, 8.47% nonfat dry and 14.57mg/dL urea nitrogen. The cell count of the cows and the bulk tank was 141,252.75 CS/mL and 363,078.05 CS/mL respectively. The TBC mean in cows and the bulk tank was 4,466.84 CFU/mL and 24,547.01 CFU/mL respectively. The main microorganisms isolated from the udder cows were Corynebacterium bovis, Staphylococcus aureus, Staphylococcus hyicus, Staphylococcus spp., Streptococcus dysgalatiae, while the bulk tank were identified more often Streptococcus spp., Enterobacter cloacae, Hafnia alveii, hemolytic Streptococcus and Streptococcus spp. Antimicrobial residues in cow milk and bulk or churn were detected in 30% and 86% respectively. The silvopastoral system showed to be good alternative to milk production in cow. However is important the care with antimicrobial residues in milk and the analysis of all quality parameters to ensure a differentiated product.

Evaluación preliminar del bioensayo para la detección de antimicrobianos en músculo bovino / Preliminary evaluation of the bioassay for the detection of antimicrobial in bovine muscle

Antecedentes: En Colombia, la vigilancia del cumplimiento de los Límites Máximos de Residuos LMRs de antimicrobianos veterinarios en carne bovina es exigua, debido a que la capacidad analítica es insuficiente para monitorear un gran número de muestras y un amplio rango de antibióticos. El bioensayo es un método microbiológico desarrollado por la agencia de salud pública (FSIS) del Departamento de Agricultura de Estados Unidos, para la detección, identificación y semicuantificación de residuos antimicrobianos. Objetivos: Se evaluó preliminarmente el bioensayo para determinar su uso como prueba de detección cualitativa para el monitoreo y vigilancia de residuos de cuatro antimicrobianos en músculo bovino, como contribución al sistema de gestión de inocuidad en el marco del Acuerdo sobre la aplicación de Medidas Sanitarias y Fitosanitarias, bajo lineamientos de la Comisión Europea, Decisión 2002/657/CE. Métodos: El protocolo de experimentación usó tejidos fortificados con diferentes concentraciones de penicilina G potásica, oxitetraciclina, eritromicina y estreptomicina, como representantes de cuatro familias de antibióticos de uso veterinario en Colombia. Para el establecimiento de los criterios de funcionamiento del bioensayo se prepararon seis repeticiones de cada uno de los niveles o concentraciones probadas por antimicrobiano, incluyendo un nivel sin fortificación y cinco niveles de concentraciones antibióticas menores, iguales y superiores al Límite Máximo de Residuos LMRs de cada uno de los antimicrobianos analizados. Resultados: Se establecieron preliminarmente los criterios de funcionamiento del método (especificidad, límites de detección y estabilidad). La técnica mostró excelente especificidad (ningún falso-positivo); los límites de detección se determinaron para los cuatro antibióticos con relación a sus respectivos LMRs: Betalactámicos (penicilina G =LMR), tetraciclinas (oxitetraciclina =LMR), macrólidos (eritromicina =LMR) y aminoglucósidos (estreptomicina >4 LMR); sin embargo, la sensibilidad del bioensayo para estreptomicina no fue satisfactoria. La estabilidad de los analitos en la matriz fortificada al límite de detección, resultó adecuada durante el período de tiempo evaluado. Conclusiones: El método del bioensayo preliminarmente evaluado es aplicable a la detección de una amplia gama de residuos antimicrobianos en músculo bovino, a concentraciones iguales a los LMRs.

Background: In Colombia, the vigilance of the Maximum Residue Limits MRLs of veterinary antimicrobials in cattle meat is limited, because the analytical capacity is insufficient to monitor a large number of samples and a wide range of antibiotics. The bioassay is a microbiological method developed by the health public agency (FSIS) of the United States Department of Agriculture (USDA) for the detection, identification and semiquantification of antimicrobial residues in cattle muscle. Objective: It was evaluated preliminary the bioassay for use as a test for the qualitative detection for monitoring and surveillance of four antimicrobials in cattle muscle, as contribution to the inocuity management system within the agreement framework about the application of Sanitary and Phytosanitary Measures; using some guidelines of the European Decision 2002/657/EC. Methods: The experimental protocol used fortified tissues with varying concentrations of penicillin G potassium, oxytetracycline, erythromycin and streptomycin, as representatives of the four important families of veterinary antibiotics used in Colombia. To establish the performance criteria of the bioassay were prepared six replicates of each of the levels or concentrations tested for antimicrobial, including a level without fortification and five levels of lower antibiotic concentrations, equal and above MRL Maximum Residue Limit for each one of the tested antimicrobials. Results: The performance characteristics of method were preliminarily determined (specificity, detection limits and stability). The test showed excellent specificity (no false positive); detection limits were determined for the four antibiotics in relation to their respective Maximum Residue Limit MRLs: Beta-lactams (penicillin G =MRL), tetracyclines (oxytetracycline =MRL), macrolides (erythromycin =MRL) and aminoglycosides (streptomycin >4 MRL); however, the sensitivity of bioassay for the streptomycin was unsatisfactory. Stability of the analytes in the matrix was adequate during the period evaluated. Conclusions: The preliminary bioassay method evaluated is applicable to the detection of a broad range of antimicrobial residues in bovine muscle at concentrations at the MRLs.

Assessment of the California mastitis test usage in smallholder dairy herds and risk of violative antimicrobial residues

This study evaluated how predictive the California Mastitis Test (CMT) is for sub-clinical mastitis under tropical smallholder dairy production conditions in Kenya. It intended to establish whether the CMT usage could be contributing to misdiagnosis and consequent mistreatment with animal drugs resulting in residue problems. Milk samples (n = 239) were aseptically collected from lactating cows in the Rift Valley of Kenya and tested using the CMT, somatic cell counts (SCC) and bacterial culture. The samples were also screened for violative drug residues using the commercial delvo test and compared to the milks mastitic status for possible association. There was a numerical but non-significant (p > 0.05) difference evident in the frequencies observed using the three different mastitis indicators. The prevalent bacterial species isolated from mammary glands with subclinical mastitis were Staphylococcus aureus (45.6%), coagulase-negative Staphylococci (13.0%), Streptococci (11.7%) and Escherichia coli 5.9%. There was an overall poor but significant (p < 0.05) correlation between the CMT and the violative antimicrobial residues in samples from all quarters, infected and non-infected respectively. The results suggest that the CMT use amongst the smallholder dairy sector as a mastitic indicator may not be a risk factor in violative antimicrobial residues problems in milk.