The aim of the present study was to assess the antibiofilm activity of daptomycin- and vancomycin-loaded poly(methyl methacrylate) (PMMA) and PMMA-Eudragit RL100 (EUD) microparticles against mature biofilms of polysaccharide intercellular adhesin-positive S. epidermidis.

The effect of plain, daptomycin- and vancomycin-loaded PMMA and PMMA-EUD microparticles on S. epidermidis biofilms was assessed by isothermal microcalorimetry (IMC) and fluorescence in situ hybridization (FISH). Biofilms were grown for 48h onto poly-urethane pieces of fixed dimensions. Each sample was washed with PBS in order to remove planktonic bacteria and incubated for 24h with different concentrations of acrylic microparticles (20–1.25 mg/mL). The minimal biofilm inhibitory concentration (MBIC) of the antibiotic-loaded particles was defined as the lowest concentration of particles that was able to prevent heat flow associated to the recovery of the biofilms. After incubation with the microparticles, sessile cocci were hybridized with the pan-bacterial EUB338-FITC and the staphylococci-specific STAPHY-FICT probes and stained with DAPI. Biofilm structure and metabolic state were characterized by fluorescence microscopy.

According to the IMC results, plain PMMA-particles showed no effect on S. epidermidis biofilms, whereas PMMA-EUD-microparticles negatively influenced the recovery of the biofilm probably due to the highly positive charge of these particles. The MBIC of daptomycin-loaded PMMA-microparticles was 20 mg/mL, whereas vancomycin-loaded PMMA microparticles were not able to inhibit biofilm recovery. Adding EUD to the formulation reduced the MBIC of daptomycin-loaded microparticles to 1.25 mg/mL, corresponding to a 16-fold reduction. Regarding the vancomycin-loaded microparticles, EUD caused a further decrease of their antibiofilm activity. The FISH micrographs corroborated the IMC results and provided additional insights on the antibiofilm effect of these carriers. According to FISH, daptomycin-loaded PMMA-EUD microparticles were responsible for the most pronounced reduction in biofilm mass. In addition, FISH showed that both PMMA and PMMA-EUD microparticles were able to attach to the biofilms.

Adding EUD to the formulations proved to be a powerful strategy to improve daptomycin-loaded microparticles antibiofilm activity. In addition, the combination of IMC and FISH was essential in order to fully assess the effect of polymeric microparticles on sessile S. epidermidis. Although the present study enabled gaining further insights on this subject, the nature of these interactions remains unclear. However, this may be a crucial aspect for the enhancement of antibiofilm activity of antibiotic-loaded polymeric microcarriers against mature biofilms.

This work was supported by the Portuguese government (Fundação para a Ciência e a Tecnologia) and FEDER (grant SFRH/BD/69260/2010 and research project EXCL/CTM-NAN/0166/2012) and strategic project PEst-OE/SAU/UI4013/2011.

Antibiotic-loaded bone cements are used to decrease occurrence of bone infections in cemented arthroplasties and actually being considered as a more cost-effective procedure when compared to cementless implants [1]. However, considering the challenge of treating device-associated infections there is a reduced number of formulations in the market. Response from the industry to medical need is still slow considering the rapid change in the infecting microbial profile and the emergence of multiresistant strains [2]. In this context, the aim of the work is to evaluate the role of lactose (L), as a porogen, on the antibiotic release from bone cement (BC). Levofloxacin (Lev) and minocycline (M) were the selected antibiotics to be individually loaded into BC due to their low cost and potential application in bone infections [3,4].

Two types of matrices were prepared: 1) Loaded with 2.5% of antibiotics (controls) and 2) Loaded with 10% lactose and 2.5% antibiotic. In vitro drug release and microbiological tests against representative strains causative of bone infections were assessed.

Lactose significantly increased the release of both antibiotics. Complete minocycline release after one-week was observed (Fig.1A). Also, lactose increased 3.5-fold the levofloxacin released from BC (Fig.1B).

Furthermore, microbiological studies showed that no interaction was observed between lactose and antibiotic as no decrease in drugs antimicrobial activity was observed (Table 1).

Considering the results, L-BC matrix appears to be a valuable alternative to available formulations. Future work will include testing other antibiotics as well as mixtures of drugs.

Fundação para a Ciência e Tecnologia (Portuguese government) for financial support: EXCL/CTM-NAN/0166/2012 and strategic project PEst-OE/SAU/UI4013/2011.

This clinical case refers to a male patient, 45 years old, with a past medical history of Hepatitis C, admitted at the Emergency Department on July 2014, after a fall from 7 meters high at his workplace – dump – which resulted in an open fracture of the distal end of the right forearm bones – Gustillo & Anderson IIIA.

With this work, the authors aim to describe the evolution of the patient's clinical status, from the initial fracture to the septic arthritis of the right wrist, as also the surgical interventions and other treatments he has undergone.

There were used all patient's records from Hospital's archives, including Emergency Department registry, Clinical Diaries, Operative Reports, and results of diagnostic exams. It was also revised all patient's clinical process, with support of photographs obtained during the successive revaluations.

The clinical case we present on this work began on July 2014, when the patient suffered an open fracture – Gustillo & Anderson IIIA – on the distal end of the right forearm bones.

The lesion was subjected to washing, closed reduction and internal fixation with Kirschner wires, and also a cycle of antibiotic.

At the fourth day after surgery, because of an unfavorable evolution of the wound, the patient was submitted to a bulky abscess drainage and a joint osteotaxis.

About 1 month and a half after the traumatic event, it was performed a revision of the osteotaxis, following a failed attempt of osteosynthesis.

By unfavorable evolution of the clinical status, with the development of septic arthritis in the right wrist, it was decided to undertake a Masquelet technique.

Analyzing the evolution of the patient's clinical status, the authors conclude that, besides the appropriate therapeutic options taken at each stage, the development of septic arthritis at the right wrist was inevitable.

This framework, in association to the fact that this is a 45 years old patient, with the dominant hand affected, raises issues of questionable therapeutic order.

This work refers to a male patient, 25 years of age, admitted in the Emergency Department following a bicycle accident, of which resulted an open fracture of the right forearm bones – Gustillo & Anderson I.

With this work, the authors have as objective the description of the patient's clinical condition – starting with the fracture, over to the osteomyelitis – as well as the surgical procedures and remaining treatments he was submitted to.

The authors used the patient's records from Hospital's archives, namely records from the Emergency Department, Operating Room, Infirmary and Consultation, and also the diagnostic exams performed throughout the patient's clinical evolution.

This clinical case began in May 2013, when the patient suffered an open fracture of the right forearm bones – Gustillo & Anderson I – due to a bicycle accident. At the time, the exposure site was thoroughly rinsed, a cast immobilization was made, and antibiotics were prescribed. In the fifth day following the trauma, the patient was submitted to an open reduction with internal fixation with plate and screws of both forearm bones. In the following period, the distal segment of the suture suffered necrosis, exposing the radial plate and the tendons of the first dorsal compartment. The Plastic Surgery team was then contacted, proposing the execution of a graft over the exposed area, which was made in August 2013. In the postoperative period, about half the graft lost its viability and it was noted that a radial pseudoarthrosis had developed – in the context of osteomyelitis – with a defect of about 9 centimeters. This condition prompted the extraction of the osteosynthesis material, about 4 months after its application, and at the same time the first stage of a Masquelet Technique was performed. The second stage of the aforementioned procedure was carried out two months later. Currently, the patient is clinically stable, with right hand mobility acceptable for his daily living activities.

Analyzing the patient's clinical evolution, we concluded that, even though the adequate therapeutic decisions have been made in each stage, the development of osteomyelitis was inevitable. This realization, in association with the patient's young age, raises debatable questions of therapeutic order.