RESUMEN
It is generally assumed that French fries are likely to have weak in vitro mutagenic activity, but most studies thereof have only assessed gene mutations. In this article, the genotoxicity of 10 extracts of French fries was assessed using the in vitro micronucleus test (following the principles of the OECD 487 guidelines). Each sample was obtained from a different mass catering company in Navarra (Spain). This assay, together with the Ames test, is recommended in the basic in vitro phase included in the European Food Safety Authority Opinion on Genotoxicity Testing Strategies Applicable to Food and Feed Safety Assessment. Eight of 10 samples from mass catering companies induced chromosomal aberrations in the in vitro micronucleus test. Moreover, French fries deep-fried in the laboratory for different periods of time (0, 3, 5, 10, 20, 30 min) were assessed using the in vitro micronucleus test. Genotoxicity was observed in all time periods from 3 min on. The biological relevance of these results must be further explored.
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Aberraciones Cromosómicas , Daño del ADN , Humanos , Pruebas de Mutagenicidad , Mutación , Pruebas de MicronúcleosRESUMEN
In accordance with the global action plan on antimicrobial resistance adopted by the World Health Assembly in 2015, there is a need to develop surveillance programs for antimicrobial resistant bacteria. In this context, we have analyzed the clonal diversity of Extended-spectrum ß-lactamase (ESBL)-producing Escherichia coli (E. coli) isolated from aquatic environments and human and food samples in Spain, with the aim of determining possible clonal complexes (CCs) that act as markers of the potential risk of transmission of these resistant bacteria. The phylogenetic groups, sequence types (STs) and CCs were determined by different Polymerase Chain Reaction (PCR) and Multilocus Sequence Typing (MLST) techniques. Phylogroup A was prevalent and was mainly present in food and water strains, while human strains were mostly associated with phylogroup B2. According to the observed prevalence in the different niches, CC23 and CC10 are proposed as markers of phylogroups A and C, related with the spread of blaCTX-M1 and blaCTX-M15 genes. Similarly, CC131 and CC38 could be associated to the dissemination of pathogenic strains (phylogroups B2 and D) carrying mainly blaCTX-M14 and blaCTX-M15 genes. Some strains isolated from wastewater treatment plants (WWTPs) showed identical profiles to those isolated from other environments, highlighting the importance that water acquires in the dissemination of bacterial resistance. In conclusion, the detection of these genetic markers in different environments could be considered as an alert in the spread of ESBL.
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According to the search for alternatives to replace antibiotics in animal production suggested in the antimicrobial resistance action plans around the world, the objective of this work was to evaluate the bactericidal effect of kaolin-silver nanomaterial for its possible inclusion as an additive in animal feed. The antibacterial activity of the C3 (kaolin-silver nanomaterial) product was tested against a wide spectrum of Gram-negative and Gram-positive bacteria (including multidrug resistant strains) by performing antibiograms, minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC), as well as growth inhibition curves against seven strains causing infections in animals. The C3 product generated inhibition halos in all the tested strains, and a higher activity against Gram-negative bacteria was found, with MBC values ranged from 7.8 µg/mL (P. aeruginosa) to 15.6 µg/mL (E. coli and Salmonella). In contrast, it was necessary to increase the concentration to 31.3 µg/mL or 250 µg/mL to eliminate 99.9% of the initial population of S. aureus ATCC 6538 and E. faecium ATCC 19434, respectively. Conversely, the inhibition growth curves showed a faster bactericidal activity against Gram-negative bacteria (between 2 and 4 h), while it took at least 24 h to observe a reduction in cell viability of S. aureus ATCC 6538. In short, this study shows that the kaolin-silver nanomaterials developed in the framework of the INTERREG POCTEFA EFA183/16/OUTBIOTICS project exhibit antibacterial activity against a wide spectrum of bacteria. However, additional studies on animal safety and environmental impact are necessary to evaluate the effectiveness of the proposed alternative in the context of One Health.
RESUMEN
The current article aimed to evaluate the in vitro mutagenicity of ten fried meat-based food extracts obtained from different catering companies from Navarra (Spain). A miniaturized 6-well version of the Ames test in Salmonella typhimurium TA98, and the in vitro micronucleus test (OECD TG 487) in TK6 cells were performed. None of the ten extracts of fried meat-based food induced gene mutations in S. typhimurium TA98 with or without metabolic activation, but five induced chromosomal aberrations after 24 h treatment of TK6 without metabolic activation. More studies are needed to check the biological relevance of these in vitro studies.
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Culinaria , Mutágenos/química , Animales , Proteínas Bacterianas/genética , Proteínas Bacterianas/metabolismo , Línea Celular , Aberraciones Cromosómicas/inducido químicamente , Cromosomas Bacterianos/efectos de los fármacos , Comercio , Regulación Bacteriana de la Expresión Génica/efectos de los fármacos , Humanos , Carne/análisis , Pruebas de Micronúcleos , Mutagénesis , Pruebas de Mutagenicidad , Salmonella typhimurium/efectos de los fármacosRESUMEN
Due to the global progress of antimicrobial resistance, the World Health Organization (WHO) published the list of the antibiotic-resistant "priority pathogens" in order to promote research and development of new antibiotics to the families of bacteria that cause severe and often deadly infections. In the framework of the One Health approach, the surveillance of these pathogens in different environments should be implemented in order to analyze their spread and the potential risk of transmission of antibiotic resistances by food and water. Therefore, the objective of this work was to determine the presence of high and critical priority pathogens included in the aforementioned list in different aquatic environments in the POCTEFA area (North Spain-South France). In addition to these pathogens, detection of colistin-resistant Enterobacteriaceae was included due its relevance as being the antibiotic of choice to treat infections caused by multidrug resistant bacteria (MDR). From the total of 80 analyzed samples, 100% of the wastewater treatment plants (WWTPs) and collectors (from hospitals and slaughterhouses) and 96.4% of the rivers, carried antibiotic resistant bacteria (ARB) against the tested antibiotics. Fifty-five (17.7%) of the isolates were identified as target microorganisms (high and critical priority pathogens of WHO list) and 58.2% (n = 32) of them came from WWTPs and collectors. Phenotypic and genotypic characterization showed that 96.4% were MDR and resistance to penicillins/cephalosporins was the most widespread. The presence of bla genes, KPC-type carbapenemases, mcr-1 and vanB genes has been confirmed. In summary, the presence of clinically relevant MDR bacteria in the studied aquatic environments demonstrates the need to improve surveillance and treatments of wastewaters from slaughterhouses, hospitals and WWTPs, in order to minimize the dispersion of resistance through the effluents of these areas.
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One of the main public health problems nowadays is the increase of antimicrobial resistance, both in the hospital environment and outside it (animal environment, food and aquatic ecosystems, among others). It is necessary to investigate the virulence-associated factors and the ability of horizontal gene transfer among bacteria for a better understanding of the pathogenicity and the mechanisms of dissemination of resistant bacteria. Therefore, the objective of this work was to detect several virulence factors genes (fimA, papC, papG III, cnf1, hlyA and aer) and to determine the conjugative capacity in a wide collection of extended-spectrum ß-lactamases-producing E. coli isolated from different sources (human, food, farms, rivers, and wastewater treatment plants). Regarding virulence genes, fimA, papC, and aer were distributed throughout all the studied environments, papG III was mostly related to clinical strains and wastewater is a route of dissemination for cnf1 and hlyA. Strains isolated from aquatic environments showed an average conjugation frequencies of 1.15 × 10-1 ± 5 × 10-1, being significantly higher than those observed in strains isolated from farms and food (p < 0.05), with frequencies of 1.53 × 10-4 ± 2.85 × 10-4 and 9.61 × 10-4 ± 1.96 × 10-3, respectively. The reported data suggest the importance that the aquatic environment (especially WWTPs) acquires for the exchange of genes and the dispersion of resistance. Therefore, specific surveillance programs of AMR indicators in wastewaters from animal or human origin are needed, in order to apply sanitation measures to reduce the burden of resistant bacteria arriving to risky environments as WWTPs.
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Presence of extended-spectrum ß-lactamase (ESBL-E), AmpC-producing and carbapenemase-producing (CPE) Enterobacteriaceae has been observed not only in the clinical environment, but also in the out-of-hospital environment. The objective of this study was to isolate and characterize strains of ESBL, AmpC, and CPE present in feces of healthy carriers in Navarra (n = 125). Despite the fact that no CPE strains were isolated, 16% and 11.2% of the studied population were ESBL-E and AmpC carriers, respectively. No significant differences were found by gender or age; young people (5-18 years old) showed the highest ESBL-E prevalence (31.8%). The isolates corresponded to E. coli (57.1%), Enterobacter spp. (28.6%), and Citrobacter freundii (14.3%), and all strains showed multidrug-resistant profiles. High resistance against cephalosporins, penicillins, and monobactams, and sensitivity to carbapenems, quinolones, and aminoglycosides were observed. With respect to ESBL producers, 52.4% were CTX-M-type (19.0% CTX-M-14, 9.5% CTX-M-1, and 28.6% CTX-M-15) and 47.6% were TEM-type (38.1% TEM-171). These results confirm the extensive dissemination of these resistances among a healthy population and pose the need to implement control measures and strategies according to the One Health approach in order to prevent the increase of severe and untreatable infections in a not far future.
Asunto(s)
Farmacorresistencia Bacteriana Múltiple/genética , Enterobacteriaceae , Heces/microbiología , beta-Lactamasas/genética , Adolescente , Adulto , Anciano , Antibacterianos/farmacología , Proteínas Bacterianas/genética , Cefalosporinas/farmacología , Niño , Preescolar , Citrobacter freundii/efectos de los fármacos , Citrobacter freundii/aislamiento & purificación , Citrobacter freundii/metabolismo , Enterobacter/efectos de los fármacos , Enterobacter/aislamiento & purificación , Enterobacter/metabolismo , Enterobacteriaceae/efectos de los fármacos , Enterobacteriaceae/aislamiento & purificación , Enterobacteriaceae/metabolismo , Escherichia coli/efectos de los fármacos , Escherichia coli/aislamiento & purificación , Escherichia coli/metabolismo , Femenino , Voluntarios Sanos , Humanos , Masculino , Pruebas de Sensibilidad Microbiana , Persona de Mediana Edad , Monobactamas/farmacología , Tipificación de Secuencias Multilocus , Penicilinas/farmacología , Prevalencia , Adulto JovenRESUMEN
Mobile genetic elements play an important role in the dissemination of antibiotic resistant bacteria among human and environmental sources. Therefore, the aim of this study was to determine the occurrence and patterns of integrons and insertion sequences of extended-spectrum ß-lactamase (ESBL)-producing Escherichia coli isolated from different sources in Navarra, northern Spain. A total of 150 isolates coming from food products, farms and feeds, aquatic environments, and humans (healthy people and hospital inpatients), were analyzed. PCRs were applied for the study of class 1, 2, and 3 integrons (intI1, intI2, and intI3), as well as for the determination of insertion sequences (IS26, ISEcp1, ISCR1, and IS903). Results show the wide presence and dissemination of intI1 (92%), while intI3 was not detected. It is remarkable, the prevalence of intI2 among food isolates, as well as the co-existence of class 1 and class 2 (8% of isolates). The majority of isolates have two or three IS elements, with the most common being IS26 (99.4%). The genetic pattern IS26â»ISEcp1 (related with the pathogen clone ST131) was present in the 22% of isolates (including human isolates). In addition, the combination ISEcp1â»IS26â»IS903â»ISCR1 was detected in 11 isolates being, to our knowledge, the first study that describes this genetic complex. Due to the wide variability observed, no relationship was determined among these mobile genetic elements and ß-lactam resistance. More investigations regarding the genetic composition of these elements are needed to understand the role of multiple types of integrons and insertion sequences on the dissemination of antimicrobial resistance genes among different environments.
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Farmacorresistencia Microbiana/genética , Infecciones por Escherichia coli/epidemiología , Escherichia coli/genética , Escherichia coli/aislamiento & purificación , beta-Lactamasas/biosíntesis , beta-Lactamasas/genética , Elementos Transponibles de ADN , Humanos , Integrones , Pruebas de Sensibilidad Microbiana , Prevalencia , España/epidemiologíaRESUMEN
The aim of this study was to determine the occurrence and patterns of resistance of extended-spectrum ß-lactamase (ESBL) producing Enterobacteriaceae in food products purchased in Navarra, northern Spain. A total of 174 samples of fish and chicken were analyzed from September 2015 to September 2016, including raw and ready-to-eat products: trout (nâ¯=â¯25), salmon (nâ¯=â¯28), panga (nâ¯=â¯13), chicken nuggets and chicken scalopes (nâ¯=â¯32), sushi (nâ¯=â¯31) and sliced cooked poultry (nâ¯=â¯45). Cefpodoxime-resistant strains were isolated on ChromID ESBL agar and further phenotypic (antimicrobial study on MicroScan© NM37 panel) and genotypic characterization (multiplex PCR, sequencing and multi-locus sequence typing, MLST) was performed to confirm and characterize ESBL producers. Raw chicken and sushi have been determined as the most risky products regarding transmission of ESBL-producing Enterobacteriaceae (occurrence 53.1% and 19.4%, respectively), while sliced cooked poultry products appear to be a safe product in this aspect. With regard to raw fish, prevalence in salmon was lower (3.6%) than in trout and panga (16.0%). Ninety-eight per cent of ESBL isolates (nâ¯=â¯50) show multidrug-resistant profiles, highlighting the high resistances against quinolones and tetracyclines observed in chicken isolates, as well as against ertapenem and chloramphenicol in sushi strains. Predominant ß-lactamase type was SHV-12 (50.1%), followed by TEM-type (24.5%) and CTX-M (20.8%). In addition, CTX-M type was only detected in chicken products. The phylogenetic study showed the prevalence of groups A (35%), F (25%) and B1 (15%), usually related to nonvirulent strains. MLST E. coli isolates (nâ¯=â¯20) were grouped into 5 clonal complexes (CC) and 15 sequence types (ST), showing high clonal diversity. ST117 was the prevalent sequence type, while the human pathogen ST131 was not detected in this study. The high prevalence of ESBL-producing multidrug-resistant Enterobacteriaceae detected in products of widespread consumption such as chicken and sushi, increases the concern regarding human exposure to superbugs and encourages the need to improve surveillance of this public health issue.
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Enterobacteriaceae , Peces/microbiología , Aves de Corral/microbiología , Alimentos Crudos/microbiología , beta-Lactamasas/genética , Animales , Antibacterianos/farmacología , Ceftizoxima/análogos & derivados , Ceftizoxima/farmacología , Pollos/microbiología , Cloranfenicol/farmacología , Farmacorresistencia Bacteriana Múltiple/genética , Enterobacteriaceae/efectos de los fármacos , Enterobacteriaceae/genética , Enterobacteriaceae/aislamiento & purificación , Ertapenem , Contaminación de Alimentos/análisis , Humanos , Pruebas de Sensibilidad Microbiana , Tipificación de Secuencias Multilocus , Filogenia , Prevalencia , Quinolonas/farmacología , Salmón/microbiología , España , Tetraciclinas/farmacología , Trucha/microbiología , beta-Lactamas/farmacología , CefpodoximaRESUMEN
This study presents a comprehensive approach of a clonal diversity analysis of 448 Extended-spectrum ß-lactamase (ESBL)-producing E. coli isolated from environmental, human and food samples in Spain. The phenotypic confirmation of ESBL production was performed by disc diffusion and microdilution methods, while Polymerase Chain Reaction (PCR) and sequencing were used for the molecular characterization of ß-lactamase genes (blaCTX-M, blaSHV, blaTEM, blaOXA). Clonal relationship of isolates was determined by multi-locus sequence typing (MLST). Multidrug resistant strains were present in all the studied niches, with percentages above 50.0%. The most prevalent ß-lactamase genes were blaCTXM-14 (26%) and blaCTXM-1 (21.4%), followed by blaSHV-12, blaCTX-M-15 and blaTEM-42. MLST isolates were grouped into 26 clonal complexes (CC) and 177 different sequence types (ST) were detected. Despite the high clonal diversity observed, CC10 was the prevalent and the only CC detected in all niches, while other complexes as CC131 were mainly associated to human isolates. The observed prevalence and diversity of these resistant bacteria across the different environments encourages a One Health approach to prevent and control ESBL dissemination between environment and consumers.
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Infecciones por Escherichia coli/microbiología , Escherichia coli/enzimología , Escherichia coli/genética , beta-Lactamasas/genética , Antibacterianos/farmacología , Farmacorresistencia Bacteriana , Regulación Bacteriana de la Expresión Génica , Regulación Enzimológica de la Expresión Génica , Humanos , Tipificación de Secuencias Multilocus , Reacción en Cadena de la Polimerasa , Prevalencia , EspañaRESUMEN
Prerequisite programs are considered the most efficient tool for a successful implementation of self-control systems to ensure food safety. The main objective of this study was to evaluate the implementation of these programs in 15 catering services located in Navarra and the Basque Country (regions in northern Spain), through on-site audits and microbiological analyses. The implementation of the prerequisite program was incomplete in 60% of the sample. The unobserved temperature control during both the storage and preparation of meals in 20% of the kitchens reveals misunderstanding in the importance of checking these critical control points. A high level of food safety and hygiene (absence of pathogens) was observed in the analyzed meals, while 27.8% of the tested surfaces exceeded the established limit for total mesophilic aerobic microorganisms (≤100 CFU/25 cm²). The group of hand-contact surfaces (oven door handles and aprons) showed the highest level of total mesophilic aerobic microorganisms and Enterobacteriaceae, and the differences observed with respect to the food-contact surfaces (work and distribution utensils) were statistically significant (P < 0.001). With regard to the food workers' hands, lower levels of microorganisms were observed in the handlers wearing gloves (that is, for Staphylococcus spp we identified 43 CFU/cm2 on average compared with 4 CFU/cm2 (P < 0.001) for those not wearing and wearing gloves, respectively). For a proper implementation of the prerequisites, it is necessary to focus on attaining a higher level of supervision of activities and better hygiene training for the food handlers, through specific activities such as informal meetings and theoretical-practical sessions adapted to the characteristics of each establishment.
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Bacterias Aerobias/crecimiento & desarrollo , Enterobacteriaceae/crecimiento & desarrollo , Manipulación de Alimentos , Microbiología de Alimentos , Inocuidad de los Alimentos , Servicios de Alimentación , Higiene , Higiene de las Manos , Humanos , EspañaRESUMEN
Fecal pathogen distributions in fresh-cut leafy vegetables are essential to develop suitable sampling plans so as to detect pathogen contaminations. In this study, a typical fresh-cut lettuce process was reproduced at pilot scale with different initial inoculum levels of Salmonella on lettuce (6-7, 4 and 1 log CFU/g). The pathogen was determined in all processed lettuce samples (n ≥ 50) and obtained count data were used to fit different probability distributions. The study showed that Salmonella is homogenously distributed on fresh-cut leafy vegetables as a result of processing (mainly washing) at all contamination levels. Negative binomial and Poisson-lognormal distributions were suitable to describe pathogen distribution at the high and medium levels. coefficient of variation modified (CV) indicated no overdispersion (i.e. clustering). Nevertheless, further research will be needed to assess the effect of using disinfectants in washing water on the final distribution pattern of pathogens in processed fresh-cut leafy vegetables.
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Escherichia coli O157/aislamiento & purificación , Manipulación de Alimentos , Microbiología de Alimentos , Lactuca/microbiología , Salmonella enterica/aislamiento & purificación , Recuento de Colonia MicrobianaRESUMEN
Water environments play an important role in the dissemination of antibiotic-resistant bacteria among humans, animals and agricultural sources. In order to assess the spread of extended-spectrum ß-lactamase (ESBL)-producing Enterobacteriaceae, we analyzed 279 effluent samples from 21 wastewater treatment plants in Navarra (northern Spain). A total of 185 cefpodoxime-resistant bacteria were isolated on ChromID ESBL agar plates, with high predominance of Escherichia coli among isolated species (73%). ESBL production was determined by different methods, concluding its presence in 86.5% of the isolates by the combination disk test, 75.7% by double-disk synergy test and 73.5% by MicroScan(®) NM37 automated system. PCR and sequencing analysis showed that the predominant ß-lactamases (bla) genes were blaCTx-M (67.4%) followed by blaTEM (47%), blaSHV (17.4%) and blaOxA (8.3%); furthermore, two or more ß-lactamases genes were found in 34.9% of the isolates. The results demonstrate the high prevalence of ESBL-producing Enterobacteriaceae in effluent water from wastewater treatment plants and confirm the need to optimize current disinfection procedures and to improve management of wastewater in an effort to minimize reservoirs of resistant bacteria. Further studies are needed for examining the presence of these bacteria in other environments and for determining the potential dissemination routes of these resistances as well as their impact on human health.
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Enterobacteriaceae/enzimología , Aguas Residuales , Microbiología del Agua , beta-Lactamasas/metabolismo , Ceftizoxima/análogos & derivados , Ceftizoxima/farmacología , Farmacorresistencia Bacteriana , Enterobacteriaceae/efectos de los fármacos , Enterobacteriaceae/aislamiento & purificación , Monitoreo del Ambiente , España , Instalaciones de Eliminación de Residuos , beta-Lactamasas/genética , CefpodoximaRESUMEN
Controlling Listeria monocytogenes in smoked salmon is still a challenge for food business operators. The reported low levels and uneven distribution of the pathogen make it necessary to apply good sampling plans and analytical procedures in order to detect contaminated batches. However, analyses are expensive and due to current economic situations, usually only one sample per lot is checked instead of the n=5 samples established in Regulation (EC) No 2073/2005. This work proposes the investigation of L. monocytogenes by pooling pre-enriched Half Fraser from several units from a batch (n=6). The results obtained from a preliminary in-house validation (n=51 pools) showed that the performance characteristics (sensitivity and specificity) are very high (>95%). This high reliability, together with reduced costs (nearly half), suggests that the wet pooling test could be a good cost-effective approach for investigating L. monocytogenes in smoked salmon. Additional research is needed before this approach can be used for other food matrices, such as determining the maximum number of units per batch that can be pooled with effective detection of L. monocytogenes.
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Microbiología de Alimentos/métodos , Listeria monocytogenes/aislamiento & purificación , Salmón/microbiología , Animales , Reproducibilidad de los Resultados , Sensibilidad y EspecificidadRESUMEN
The aim of this study was to obtain data from refrigerated ready-to-eat seafood products at retail in Spain (young eels, crabstick and smoked salmon), regarding prevalence and levels of Listeria monocytogenes, storage temperatures and the impact of transport conditions (type of bag) on the temperature of the product. The one-year surveillance period was carried out according to the EC Regulation No. 2073/2005, taking 5 units/batch and analyzing 250 samples following ISO 11290-1/A1 and ISO 11290-2/A methodologies. Low prevalence of L. monocytogenes was observed in surimi products, while 4.8% of smoked salmon samples were positive for Listeria with low levels (<10 cfu/g) and uneven pathogen distribution. A single company was responsible for 80% of the positive lots. All purchased products showed values higher than 4 °C at retail and an average increase of 2.5 °C or up to 6.2 °C was recorded when isothermal or plastic shopping bags were used for transport, respectively. To avoid noncompliance of the Food Safety Objective for L. monocytogenes in seafood RTE products more efforts from all stakeholders are needed, with special attention so as to improve control and maintenance of refrigerators at retail and to enhance consumer education regarding food safety practices.
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Comida Rápida/microbiología , Contaminación de Alimentos/estadística & datos numéricos , Listeria monocytogenes/aislamiento & purificación , Alimentos Marinos/microbiología , Animales , Seguridad de Productos para el Consumidor , Anguilas , Contaminación de Alimentos/análisis , Almacenamiento de Alimentos , Listeria monocytogenes/genética , Salmón , TemperaturaRESUMEN
Patterns of resistance in ß-lactamase-producing Enterobacteriaceae family were investigated in isolates from 141 meat products (beef, poultry and pork) purchased in Spain. The strains that grow in ChromID ESBL agar plates were confirmed using the paired disk diffusion method. Resistance to amoxicillin/clavulanic acid, ceftazidime, ceftriaxone, aztreonam, cefpodoxime, gentamicin, doxycycline, cotrimoxazol, norfloxacin, piperacillin/tazobactam, fosfomycin and cefoxitin were tested following CLSI recommendations. Minimum inhibitory concentrations were determined by the MicroScan® NM37 panel and ß-lactamase genes were detected using multiplex PCR and sequencing. Results show poultry as the meat product having the highest prevalence (84%), with Escherichia coli being the predominant bacteria (71.3%). Predominant ß-lactamase types were CTX-M (37.8%), followed by CTX-M+TEM combination (20.7%), TEM (17%), SHV (12.2%), TEM+SHV combination (10.9%) and OXA (1.2%). 93.9% of the strains were resistant to one or more ß-lactam antibiotics. Results indicate a widespread distribution of ESBL-producing Enterobacteriaceae in meat products, with a high rate of ß-lactam resistance and a low rate of AmpC cephalosporinase-producing strains.
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Enterobacteriaceae/aislamiento & purificación , Contaminación de Alimentos/análisis , Microbiología de Alimentos , Productos de la Carne/microbiología , beta-Lactamasas/metabolismo , Animales , Antibacterianos/farmacología , Aztreonam/farmacología , Bovinos , Cefotaxima/farmacología , Ceftazidima/farmacología , Ceftizoxima/análogos & derivados , Ceftizoxima/farmacología , Farmacorresistencia Bacteriana Múltiple/efectos de los fármacos , Enterobacteriaceae/crecimiento & desarrollo , Pruebas de Sensibilidad Microbiana , Aves de Corral , Prevalencia , España , Porcinos , Resistencia betalactámica/efectos de los fármacos , beta-Lactamasas/genética , CefpodoximaRESUMEN
The susceptibility of 440 Listeria monocytogenes strains isolated from food (n=401) and clinical cases (n=39) between 1995 and 2005 was determined by standard agar dilution and E-test methods. Antimicrobial drugs currently used in veterinary and human therapy were tested, and they included penicillin G, ampicillin, cephalothin, gentamicin, chloramphenicol, tetracycline, doxycycline, trimethoprim, erythromycin, and clindamycin. The sensitivity of strains was established using Clinical and Laboratory Standards Institute (formerly NCCLS) breakpoints and MIC50 (the MIC for 50% of the strains) to MIC90 values. In general, isolates were susceptible to the majority of the antimicrobials tested, including beta-lactamics and aminoglycosides, which are normally used in the treatment of listeriosis. Resistance to tetracycline and doxycycline was found in five strains isolated from fresh trout belonging to the same fish farm. Molecular analysis by restriction endonuclease analysis showed a similar profile, suggesting the persistence of a strain well adapted to the presence of tetracycline in the environment of a fish farm, which is frequently used in aquaculture in order to prevent infections of fish.
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Antibacterianos/farmacología , Farmacorresistencia Bacteriana , Contaminación de Alimentos/análisis , Listeria monocytogenes/efectos de los fármacos , Listeriosis/tratamiento farmacológico , Alimentos Marinos/microbiología , Acuicultura , Recuento de Colonia Microbiana , Relación Dosis-Respuesta a Droga , Microbiología de Alimentos , Humanos , Listeriosis/microbiología , Pruebas de Sensibilidad Microbiana , EspañaRESUMEN
Gentamicin is an aminoglycoside with a wide spectrum of antibacterial activity. However, as a highly water-soluble drug, it penetrates cells poorly. This constitutes a particularly important drawback for treating intracellular bacterial infections. This major hurdle may be solved by the use of vectors to deliver and target bioactive agents to the intracellular sites of infection. Thus, in the case of antimicrobials, drug delivery systems may help to increase their therapeutic index in intracellular locations. The development and evolution of pharmaceutical forms of gentamicin for the parenteral treatment of intracellular pathogens is reviewed in this paper.
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Infecciones Bacterianas/tratamiento farmacológico , Sistemas de Liberación de Medicamentos/métodos , Gentamicinas/administración & dosificación , Animales , Portadores de Fármacos/síntesis química , Portadores de Fármacos/química , Gentamicinas/química , Gentamicinas/uso terapéutico , Humanos , Infusiones Parenterales , Liposomas , Nanopartículas/químicaRESUMEN
Brucellosis is a highly contagious bacterial zoonosis that affects millions of people worldwide. Brucella is highly infectious, especially when aerosolized. The infection induces severe protracted diseases, which are both debilitating and incapacitating, hence, Brucella melitensis has been considered a potential biological warfare agent. In the battle against Brucella, it is crucial to know its chemical-structure and biochemistry-metabolic characteristics. It is well known that Brucella, as well as many other intracellular bacterial pathogens, has evolved to survive and even proliferate within monocytes and macrophages cells. Depending on the route of entry (complement, Fc, lectin or fibronectin receptors), the fate of the bacteria will vary; it may even segregate from the endocytic route towards the endoplasmic reticulum. This intracellular "non regular" behaviour of Brucella makes treatment difficult. Most antibiotics, although effective in vitro, do not actively pass through cellular membranes, or, once inside, may not reach the discrete intracellular niche where the bacteria is hidden. Therefore, complete eradication of the microorganisms is difficult to achieve, and the incidence of relapses is rather high. Taking these data into consideration, this review will evaluate the past, current and new trends in the control of brucellosis, paying special attention to the drug delivery systems as potential vectors for targeting these intracellular sites where the organisms are located.
Asunto(s)
Antibacterianos , Brucella/efectos de los fármacos , Brucelosis/tratamiento farmacológico , Sistemas de Liberación de Medicamentos/métodos , Animales , Antibacterianos/administración & dosificación , Antibacterianos/farmacocinética , Antibacterianos/farmacología , Antibacterianos/uso terapéutico , Brucella/aislamiento & purificación , Brucelosis/microbiología , Humanos , Macrófagos/metabolismo , Macrófagos/microbiología , Monocitos/metabolismo , Monocitos/microbiologíaRESUMEN
A survey was conducted to investigate the relationship between knowledge about food safety and actual food handling practices among Spanish university students (mainly from the health sciences disciplines) who usually prepare meals at home. Based on level of education in food safety topics, students were divided in three groups: high, which included students from Food Science and Nutrition; medium, which included students from other health sciences; and low, which included students from non-health-related studies. More than two thirds of the 562 people selected had an accurate knowledge of the eight foodborne pathogens included in the survey, but only 5.2% were able to identify Staphylococcus aureus as a foodborne pathogen. Significant differences in responses were found depending on educational level concerning the food safety topic. For food handling, up to 60% of the responses reflected accurate knowledge of proper storage of prepared meals and washing of hands and materials to avoid cross-contamination. However, with the exception of questions related to storage temperature, there was considerable difference between knowledge and reported behavior. Although 98.6% of the participants recognized the importance of hand washing before and during food preparation, only one quarter (24.4%) affirmed that they washed their hands with soap and water. On questions concerning food practices, more accurate answers were given by the older students. Women answered questions regarding cross-contamination more accurately, whereas men were more accurate in response to questions concerning temperature and food preservation. In general, students with more knowledge of food hygiene had better reported practices, but even these students reported some high-risk behaviors. These results confirm the need to improve educational programs, ensuring that the acquired knowledge actually modifies consumer behavior.