Haemodialysis catheter-related bloodstream infections at Universitas Academic Hospital, Bloemfontein: should we change our empiric antibiotics?

Detection of multidrug resistant environmental isolates of acinetobacter and Stenotrophomonas maltophilia: a possible threat for community acquired infections?

Acinetobacter spp. and Stenotrophomonas maltophilia are bacteria commonly associated with infections at the clinical settings. Reports of infections caused by environmental isolates are rare. Therefore, this study focused on determination of the antibiotic resistance patterns, antibiotic resistance genes, efflux pumps and virulence signatures of Acinetobacter spp. and S. maltophilia recovered from river water, plant rhizosphere and river sediment samples. The isolates were identified and confirmed using biochemical tests and PCR. The antimicrobial resistance profiles of the isolates were determined using Kirby Bauer disk diffusion assay and presence of antibiotic resistance and virulence genes were detected using PCR. S. maltophilia was more frequent in plant rhizosphere and sediment samples than the water samples. Acinetobacter spp. were mostly resistant to trimethoprim-sulfamethoxazole (96% of isolates), followed by polymyxin b (86%), cefixime (54%), colistin (42%), ampicillin (35%) and meropenem (19%). The S. maltophilia isolates displayed total resistance (100%) to trimethoprim- sulfamethoxazole, meropenem, imipenem, ampicillin and cefixime, while 80% of the isolates were resistant to ceftazidime. Acinetobacter spp. contained different antibiotic resistance genes such as sul1 (24% of isolates), sul2 (29%), blaOXA 23/51 (21%) and blaTEM (29%), while S. maltophilia harbored sul1 (8%) and blaTEM (20%). Additionally, efflux pump genes were present in all S. maltophilia isolates. The presence of multidrug resistant Acinetobacter spp. and Stenotrophomonas maltophilia in surface water raises concerns for community-acquired infections as this water is directly been used by the community for various purposes. Therefore, there is the need to institute measures aimed at reducing the risks of these infections and the resulting burden this may have on the health care system within the study area.

Antibacterial Capability, Physicochemical Properties, and Biocompatibility of nTiO₂ Incorporated Polymeric Scaffolds

Postoperative infection is a common risk which brings about failure in bone transplantation. In this study, nano titanium dioxide (nTiO₂) was incorporated into Polyetheretherketone/polyglycolicacid (PEEK/PGA) blends to construct antibacterial scaffolds via selective laser sintering. Antibacterial capability was assessed using Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). The results demonstrated that the scaffolds with nTiO₂ presented an effective antibacterial activity, which might be attributed to that nTiO₂ would do the mechanical and oxidative damage to bacteria by occurring contact actions and generating reactive oxygen species (ROS), and thus killed bacteria from structure and function. Moreover, nTiO₂ could enhance the tensile strength and modulus of scaffolds due to the reinforcing effect and its uniform disperse. And the cell culture experiments showed that nTiO₂ stimulated cellular attachment and proliferation. Besides, it also elevated the hydrophily and thermal stability of scaffolds. These results suggested that the polymeric scaffolds incorporated nTiO₂ had potential application in bone tissue engineering.