Antibacterial Efficacy and Drug-release Behavior Study of β-tricalcium Phosphate Micro-granules Against Staphylococcus aureus and Escherichia coli

@#Introduction: This study aims to investigate different residue sizes of β-tricalcium phosphate (β-TCP) micro-granules as carriers to assess antibacterial activity and drug-control release behavior of ampicillin (AMP-) and antimycotic (AMC-). Incorporation of antibiotic into the β-TCP micro-granules and it sustain release behavior could be used as alternative solution to reduce the risk of osteomyelitis and bone infections risks. Methods: Three different residue sizes (less than 300 µm, 300 µm and 600 µm) were prepared and coated with antibiotics solution (20 µg/µl of ampicillin and 100X antimycotic solution) by using two methods; dip and stream coating. After 72 h, 1.5 mL of distilled water was added to the treated (β-TCP) micro-granules at two different pH value (5.0 and 7.4). The extracted solution was further analyzed by Kirby Bauer disc diffusion test and spectrophotometer assay. Results: The solution containing AMC-(β-TCP) micro-granules with the size of 300 µm residue produced the largest inhibition zones against Escherichia coli (E. coli). All residue sizes coated with AMP- showed no antibacterial activity against both strains; Staphylococcus aureus (S. aureus) and E.coli. Additionally, the release behavior of AMC-(β-TCP) micro-granules was found not depending on the pH, but on the size of residue. Complete drug release was rapidly observed within 48 h. Conclusion: Based on this findings, it showed AMC-(β-TCP) micro-granules had an antibacterial activity against Gram-negative strain. Specifically, it can reduced the growth rate of E. coli and the rapid release behavior of AMC(β-TCP) micro-granules help in minimizing the risk-infections in early stage of implantation.

Estudio bacteriológico de sushi preparado y comercializado en San José, Costa Rica / Bacteriological study of prepared and commercialized sushi in San Jose, Costa Rica

Objetivo: Conocer la calidad bacteriológica de muestras de sushi expendidas en diferentes restaurantes de la provincia de San José en Costa Rica. Materiales y Método: Se analizaron 60 muestras de éste producto, a las cuales se les realizó mediante los procedimientos descritos en el Compendio de Métodos para el Examen Microbiológico de Alimentos, los siguientes análisis: recuento total aerobio mesófilo, número más probable de coliformes termotolerantes, fecales y E. coli, recuento de S. aureus y número más probable de B. cereus. Adicionalmente se investigó la presencia de patógenos relacionados con el sushi como: L. monocytogenes, Salmonella sp. y V parahaemolitycus. Resultados: El 6 (46%) establecimientos presentaron positividad por E coli, aunque en poca cantidad (1 a 10 NMP/ g en promedio). Siete establecimientos (54%) mostraron presencia de S. aureus, la mayoría en el orden de 10² UFC/ g. Adicionalmente, se logró aislar 2 cepas de B. cereus y2 de L. monocytogenes. No fue posible establecer la presencia de Salmonella sp. ni Vibrio parahaemolyticus en ninguna de las muestras evaluadas. Discusión: Según el Reglamento Técnico Centroamericano RTCA 67.04.50:08, en su sección 17.1 el 62% (8) de los establecimientos incluidos en el estudio incumplen con la norma establecida para este tipo de alimento. Esta no conformidad se da en la mayoría de los casos por la presencia de cantidades de S. aureus superiores a las 100 UFC/g.

Objective: Knowing the bacteriological quality of samples issued at different sushi restaurants in the province of San José in Costa Rica. Methods: Sixty sushi samples, acquired from different restaurants from the province of San José, Costa Rica were analyzed in order to determine their bacteriological quality. Methodology followed was that described in the Compendium of Methods for the Microbiological Examination of Food and included total aerobic plate count, Staphylococus aureus plate count, Most Probable Number of total and fecal coliforms, Escherichia coli, and B. cereus. Also, the presence of potential pathogens found in sushi including Salmonella sp., Listeria monocytogenes and Vibrio parahaemolyticus was analyzed. Results: That 6 (46%) of the restaurants were positive for E. coli, even though in small quantities (1 to to NMP/g average). S. aureus was isolated from seven restaurants (54%) also in small concentrations (10²CFU/g). In addition, two strains of B cereus and two of L monocytogenes were isolated. Neither Salmonella sp nor Vibrio parahaemolyticus were isolated from the samples evaluated. Discussion: According to the Central American Technical Regulation RTCA 67 04 50 08 sections 17.1 62% (8) of the restaurants included in this study do not comply with the regulations established for this kind of food. This nonconformity is due, mainly, to the presence of S aureus in concentrations greater than 100 CFU/g.

Evaluation of antimicrobial efficacy of nano coated silver-titania metallic plates against selective pathogens

Aim: Nanotechnology is an increasingly growing field with its current application in Science and Technology for the purpose of manufacture of novel materials at the nanoscale level. Silver-Titania nanoparticles (AgTiO2-NPs) have been known to have inhibitory and bactericidal effects. Methodology and Results: In the present study, stable silver-titania nanoparticles coated metallic blocks were prepared for testing their efficacy against selected bacterial pathogens like Escherichia coli and Staphylococcus aureus. In the experimental part, the bacterial pathogens were inoculated on silver-titania nanoparticle coated blocks and the treatment was carried out in „0‟ time and „24‟ h interval and were enumerated. Conclusion, significance and impact of study:The results were compared with the control (uncoated metallic blocks) and analyzed by using Japanese Industrial Standard (JIS Z2801:2000) method. From this study, it was concluded that silver-titania nanoparticles has inhibitory effect on bacterial pathogen tested.

Study on a Pre-enrichment Medium for the Simultaneous Recovery of Salmonella spp., Escherichia coli and Staphylococcus aureus / 微生物学通报

This text involved with a pre-enrichment medium for the simultaneous recovery of Salmonella spp.,Escherichia coli and Staphylococcus aureus.This medium is named buffered saline broth(BSB),which contains peptone 10g,beef exact 3g,disodium hydrogen phosphate 9g,potassium dihydrogen phosphate 1.5g,additive 50g,deionized water 1 000mL,pH7.2.1cfu per one milliliter of Salmonella spp.,Escherichia coli and Staphylococcus aureus in saline were stimutaneously added to 97 mL of BSB,buffered peptone water,lactose broth,nutrient broth,Escherichia coli broth,rappaport-vassiliadis enrichment broth,7.5% sodium chloride enrichment medium,respectively,and incubated for 18h at 37℃.The results showed BSB was the best enrichment medium,in which Salmonella spp.,Escherichia coli and Staphylococcus aureus multiplied at nearly same speed,and reached at 10~6 、10~6 、10~7 cfu/mL,respectively.Multiplex PCR produced specific amplicons of expected sizes,284bp for Salmonella spp.invA gene,622bp for Escherichia coli phoA gene,484bp for Staphylococcus aureus nuc gene.In contrast,the three bacteria couldn't multiply harmoniously in the other six media.So BSB might be considered as the medium,which could enrich above mentioned three bacteria.

Detection of Salmonella spp.,Escherichia coli and Staphylococcus aureus by Multiplex PCR / 微生物学通报

According to DNA sequences of the invA gene of Salmonella spp.,the phoA gene of Escherichia coli and the nuc gene of Staphylococcus aureus,three pairs of oligonucleotide primers were designed and synthesized to amplify the special DNA sequences by multiplex PCR. Moreover,the reaction conditions of multiplex PCR were optimized. The results showed the multiplex PCR using the three pairs of primers produced specific amplicons of expected sizes,284bp for Salmonella spp.,622bp for Escherichia coli,484bp for Staphylococcus aureus. The optimized reaction conditions followed as the concentration of primer 40nmol/L for Salmonella spp.,40nmol/L for Escherichia coli,80nmol/L for Staphylococcus aureus,2.4mmol/L Mg 2+ ,200?mol/L dNTP,1.5U Taq DNA polymerase,anneal temperature from 55.0℃ to 57.4℃. Under the condition,the detection limits for DNA template were 10.2pg,10.2pg and 102.0pg for Salmonella spp.,Escherichia coli and Staphylococcus aureus,respectively. The whole process could be completed within 4h. The multiplex PCR assay was a specific,sensitive,rapid and reliable method for detecting Salmonella spp.,Escherichia coli and Staphylococcus aureus,which establish important foundation for simultaneous detection for these three bacteria in food.