Conventional treatment of osteomyelitis involves the repeated surgical removal of dead bone tissue coupled with repeated irrigation of the wound and prolonged systemic administration of antibiotics. Therapy of bone infections could easily last the rest of the patient's life because of the poor accessibility of the infection site by common systemically administered antibiotics. The objective of the present study is to develop a novel bone bioactive resorbable nanocomposite that can serve as a delivery system for antibiotics. We synthesized three different samples of porous bioactive resorbable silica-calcium phosphate nanocomposite (C3S1, C1S1, and C1S3) that has the ability to provide a sustained release of effective dose of gentamicin for 28 days. Porosity measurements showed that the average pore diameter of C3S1, C1S1, and C1S3 samples is 44.8, 54.4, and 70.9 nm, respectively. Moreover, the silica-rich composite (C1S3) is characterized by a significantly higher surface area (155.8 m(2)/g) than the silica-poor samples (C3S1) (42.9 m(2)/g). For all samples, the release profile study showed initial burst release followed by a sustained release of gentamicin. The released gentamicin has a strong inhibitory effect on Staphylococcus aureus bacteria. In addition FTIR analysis showed the formation of a biological apatite layer on the material surface after 24 h of immersion in simulated body fluid. Results of the study suggest that the silica-calcium phosphate nanocomposite can serve as a delivery vehicle for gentamicin to treat osteomyelitis and regenerate bone.

Enterococcus spp. are remarkable multidrug resistant (MDR) bacteria that are causing serious healthcare-associated infections. The current study investigated the frequency of Enterococcus spp., antimicrobial susceptibility, biofilm formation and the presence of some plasmid-mediated virulence characters and antimicrobial resistance determinants in enterococcal isolates from Egyptian hospitals in Cairo. Enterococcus bacterial isolates were recovered from different clinical specimens and identified using biochemical testing and KB005A HiStrep™ identification kit. Kirby-Bauer disc diffusion method and/or broth microdilution method were used to determine the antimicrobial susceptibility patterns. Phenotypic assays were performed to study biofilm formation and cytolysin and gelatinase production. PCR assays targeting the plasmid-carried genes aac(6’)-aph(2’), aph(3)-IIIa, vanA, agg and cylA were performed. In this study, 50 isolates of diverse Enterococcus spp. were identified with E. faecium was the most frequently isolated one. High resistance profiles were determined against tested antimicrobials and all isolates were MDR. Moderate biofilm formation was detected in 20% of isolates, 18% showed complete blood hemolysis and 12% produced gelatinase. All isolates carried the tested aminoglycosides resistance genes, while vanA was found only in 4 isolates (8%). The virulence genes agg and cylA were detected in 4% and 32% of isolates, respectively. In conclusion, E. faecium was the most prevalent species. The entire isolates set were MDR and the plasmid-carried aminoglycoside resistance genes were extensively disseminated among MDR isolates. Thus, regular surveillance studies, from the area of study or other geographical regions in Egypt, and strict infection control measures are required to monitor the emerging MDR enterococci.

Purpose The use of laser sintering (LS) in the medical sector has increased dramatically in recent years. With the move towards direct use of these parts in clinical applications, there is a greater need to understand the effects of standard processes on the part properties. The purpose of this study is to determine the effect that steam sterilisation has on the mechanical properties of LS polyamide 12 parts. Design/methodology/approach The research presented here focusses on the effect of a single steam sterilisation cycle on the mechanical properties of polyamide 12 parts manufactured using LS. The influence of water content on the properties was investigated, with additional drying steps trialled to establish the potential to reverse any changes observed and to determine their root cause. Findings The results show that steam sterilisation has a significant effect on the mechanical properties of LS polyamide 12 parts, with a 39% reduction in elastic modulus, a 13% decrease in ultimate tensile strength and a 64% increase in the elongation at break. These properties were also all found to correlate with the water content, suggesting that this was the cause of the difference. The original properties of the parts were able to be recovered after oven drying. Practical implications These results show that with an additional drying step, LS polyamide 12 parts can be steam sterilised with no effect on the mechanical properties. Originality/value This is believed to be the first investigation into the effects of steam sterilisation in isolation on LS polyamide 12 parts, the first instance of drying parts to recover mechanical properties and the first instance of multiple water content measurements being directly linked to the mechanical properties.

The most common uropathogen is Escherichia coli, which causes more than 80% of catheterassociated urinary tract infections (CAUTI). Catheter-associated uropathogenic E. coli is difficult to be eradicated due to biofilm formation alongside increasing antibiotic resistance. The goal of this study is to determine the prevalence of biofilm and non-biofilm producing uropathogenic E. coli isolates and the antibiogram of E. coli isolates among catheterized patients who were admitted to Mansoura's University Hospitals. Also, the expression of bla-CTX-M and Fim H genes was determined using quantitative real-time PCR. The correlation between expression of bla-CTX-M and Fim H genes was detected. Isolated E. coli were highly resistant to nitrofurantoin (75%), ceftazidime (72%), ceftriaxone (71%), amikacin (71%), piperacillintazobactam (61%), and cefepime (53%). Biofilm formation was detected in all E. coli isolates. Also, bla-CTX-M and FimH genes were highly expressed in all E. coli isolates, as their expression is higher than the reference gene by 359.3 and 914.6 folds respectively. Insignificant positive correlation was detected between bla-CTX-M expression and FimH expression (r= 0.05, P-value= 0). These findings confirmed the serious infections caused in the catheterized patients, hence the importance of performing appropriate aseptic procedures when inserting and maintaining catheters to avoid CAUTI.

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