Influence of Quaternary Ammonium Salt Functionalized Chitosan Additive as Sustainable Filler for High-Density Polyethylene Composites

In this study, an antimicrobial packaging material was successfully developed with blends of high-density polyethylene (HDPE) and chitosan (CS) made by melt processing. In the different HDPE/CS composites, the CS content effect (up to 40%), and the addition of quaternary ammonium salt functionalized chitosan (CS-CTAB) as an additive were evaluated by X-ray diffraction (XRD), differential scanning calorimetry (DSC), thermogravimetric analyses (TG), tensile strength, scanning electron microscopy (SEM) and antimicrobial activity. When analyzing the effect of the additive in the different HDPE/CS composites, it was observed that the compositions with 10 and 20 %wt of chitosan showed better elongation values (~13% and 10%) as well as a higher decomposition temperature at 20% mass loss (T20) varying from (321-332 °C and 302-312 °C), respectively, in relation to the other compositions, regardless of the type of additive used, it acted as an antimicrobial agent, promoting inhibition of microbial growth against the strains gram-positive and gram-negative used in this work, making the different HDPE/CS composites suitable candidates for use in food packaging.

Subgingival occurrence and antimicrobial susceptibility of enteric rods and pseudomonads from Brazilian periodontitis patients

The occurrence and in vitro antimicrobial sensitivity of isolates of enteric rods and pseudomonads were examined in 80 periodontitis patients, 17 to 58 years of age, in São Paulo, Brazil. Speciation and in vitro antimicrobial susceptibility testing were performed using the BBL Crystal enteric/nonfermenter system and the Etest for amoxicillin/clavulanic acid, ciprofloxacin and doxycycline. A total of 30 strains were isolated from 25 (31.2%) of the study subjects. Pseudomonas aeruginosa occurred in nine patients, Serratia marcescens in seven, and five other species were recovered in lower prevalence. All study organisms demonstrated high susceptibility to ciprofloxacin but exhibited variable susceptibility patterns to the other antimicrobial agents tested. In conclusion, the high occurrence of enteric rods and pseudomonads in these subjects may be important in the pathogenesis of periodontitis, and ciprofloxacin might be the antibiotic of choice to eradicate these pathogens from periodontal pockets.