The consequences and prevention of bacterial biofilm infection of silicone breast implants

Thesis by publication.Bibliography: pages 201-239.Chapter 1. Where did this story begin? -- Chapter 2. Materials and methods -- Chapter 3. Presence of biofilm containing viable multiresistant organisms despite terminal cleaning on clinical surfaces in an Intensive Care Unit -- Chapter 4. An interesting finding -- Chapter 5. is there infection after implant insertion? -- Chapter 6. Does the implant surface play a role in the formation of capsular contracture in the porcine model? -- Chapter 7. Can bacterial biofilm be prevented -- Chapter 8. Biofilm at the implant interface -- Chapter 9. Conclusion.Bacteria are one of the most successful organisms on the Earth’s surface. Mankind has evolved to utilise many of the actions of bacteria to our benefit and advantage, such as synergistic bacterial colonisation of the gut and its function in digestion. Bacteria also cause many human diseases. Indeed one of the most important human advances over the past 200 years has been the rapid development of the Discipline of Microbiology as it has given medicine the knowledge and ability to now treat and cure many of these previously life-threatening infections.The discovery of bacteria living within communal structures, or biofilms, in the 1970’s challenged much of our scientific and medical knowledge of bacteria in health and disease. Bacterial biofilms are now acknowledged to be important in the aetiology of many infections, including infections of surgical implants. Biofilm infection is estimated to occur in between 1-9% of all surgical implants, depending on the device. These infections are characterised by a chronic indolent inflammatory process that can be punctuated by localised or embolic septic events. They are very difficult to diagnose and treat, commonly requiring surgical removal with or without implant replacement and are associated with rapidly increasing health care costs that are not sustainable into the future.Silicone breast implants are just one type of surgical implant where bacterial biofilm infection has been implicated in a chronic fibrotic inflammation of the implant capsule. There is now increasing evidence that this may lead to capsular contracture, the most common long-term complication of silicone breast implants.This thesis reviews the evidence for the role of bacterial biofilm infection of breast implants and the formation of capsular contracture. It also uses the porcine model of biofilm infection of silicone implants to: 1) further investigate the role of endogenous breast bacteria in the development of capsular contracture; 2) evaluate the ability of a novel antibiotic prosthetic cover to prevent bacterial biofilm infection; 3) investigate the cellular immune response to biofilm infection of silicone implants; and 4) postulate whether biofilm-related chronic inflammation and its immune response may be implicated in the neoplastic process of the new entity of breast implant-associated anaplastic large cell lymphoma.Mode of access: World wide web1 online resource (xiv, 258 pages) illustrations (some colour

Single Nucleotide Primer Extension (SNuPE) analysis of the G6PD gene in somatic cells and oocytes of a kangaroo (Macropus robustus)

cDNA sequence analysis of the X-linked glucose-6-phosphate dehydrogenase (G6PD) gene has shown a base difference between two subspecies of the kangaroo, Macropus robustus robustus (wallaroo) and M. r. erubescens (euro). A thymine residue in the wallaroo at position 358 in exon 5 has been replaced by a cytosine residue in the euro, which accounts for the previously reported electrophoretic difference between the two subspecies. This base difference allowed use of the Single Nucleotide Primer Extension (SNuPE) technique to study allele-specific expression of G6PD at the transcriptional level. We began by examining G6PD expression in somatic cells and observed complete paternal X inactivation in all somatic tissues of adult female heterozygotes, whereas we found partial paternal allele activity in cultured fibroblasts, thus confirming previous allozyme electrophoresis studies. In late dictyate oocytes from an adult heterozygote, the assay also detected expression of both the maternal and paternal alleles at the G6PD locus, with the maternal allele showing preferential expression. Thus reactivation of the inactive paternally derived X chromosome occurs during oogenesis in M. robustus, although the exact timing of reactivation remains to be determined

A Review of bacterial biofilms and their role in device-associated infection

Background Most of the world's bacteria live in biofilms, three-dimensional clusters attached to surfaces. Many hospital-acquired infections are associated with biofilm infections of implantable medical devices such as orthopaedic prostheses and intravascular catheters. Within biofilms, bacteria are significantly less susceptible to antibiotics and host defences, making biofilm infections difficult to diagnose and treat, and often necessitating removal of the infected implant. Method In this review article we describe the process of biofilm formation, quorum sensing, and biofilm infection of the healthcare environment, surgical instruments and implantable medical devices. Conclusion The inability to treat biofilm-infected devices means that therapies targeting biofilm-specific processes and targeting prevention of biofilm formation are required.6 page(s

Biofilm on Toothbrushes of Children with Cystic Fibrosis: A Potential Source of Lung Re-Infection after Antibiotic Treatment?

Frequent recurrent lung infections result in irreversible lung damage in children with cystic fibrosis (CF). This study aimed to determine if toothbrushes contain biofilms of pathogens, and act as potential reservoirs for lung re-infection following antibiotic treatment of acute exacerbations. Toothbrushes were collected from children with CF of lung infection before, during and after antibiotic treatment. Toothbrushes were rinsed with sterile saline and cultured. Bacterial isolates from toothbrushes were identified by 16s rRNA gene sequencing and compared with isolates from a sputum sample of the same patient. Scanning electron microscopy (SEM) was used to visually confirm the presence of bacterial biofilms and confocal laser scanning microscopy (CLSM) combined with Live/Dead stain to confirm bacterial viability. Large numbers of bacteria and biofilms were present on all toothbrushes. SEM confirmed the presence of biofilms and CLSM confirmed bacterial viability on all toothbrushes. Pathogens identified on toothbrushes from children before and during antibiotics treatment were in concordance with the species found in sputum samples. Pseudomonas aeruginosa and Staphylococcus aureus was able to be cultured from children’s toothbrushes despite antibiotic treatment. Toothbrushes were shown to be contaminated with viable pathogens and biofilms before and during antibiotic treatment and could be a potential source of lung re-infections

Detection of bacterial biofilm in double capsule surrounding mammary implants : findings in human and porcine breast augmentation

The finding of a double capsule surrounding breast implants is a recognized complication of breast augmentation surgery. In a recent review, double capsules were identified in 14 of 626 breast implants. We report the detection of incidental double capsules both in a patient and from our previously described porcine model.3 page(s

Chronic biofilm infection in breast implants is associated with an increased T-Cell lymphocytic infiltrate : implications for breast implant-associated lymphoma

Background: Biofilm infection of breast implants significantly potentiates capsular contracture. This study investigated whether chronic biofilm infection could promote T-cell hyperplasia. Methods: In the pig study, 12 textured and 12 smooth implants were inserted into three adult pigs. Implants were left in situ for a mean period of 8.75 months. In the human study, 57 capsules from patients with Baker grade IV contracture were collected prospectively over a 4-year period. Biofilm and surrounding lymphocytes were analyzed using culture, nucleic acid, and visualization techniques. Results: In the pig study, all samples were positive for bacterial biofilm. There was a significant correlation between the bacterial numbers and grade of capsular contracture (p = 0.04). Quantitative real-time polymerase chain reaction showed that all lymphocytes were significantly more numerous on textured compared with smooth implants (p < 0.001). T cells accounted for the majority of the lymphocytic infiltrate. Imaging confirmed the presence of activated lymphocytes. In the human study, all capsules were positive for biofilm. Analysis of lymphocyte numbers showed a T-cell predominance (p < 0.001). There was a significant linear correlation between the number of T and B cells and the number of detected bacteria (p < 0.001). Subset analysis showed a significantly higher number of bacteria for polyurethane implants (p < 0.005). Conclusions: Chronic biofilm infection around breast prostheses produces an increased T-cell response both in the pig and in humans. A possible link between bacterial biofilm and T-cell hyperplasia is significant in light of breast implant-associated anaplastic large-cell lymphoma.11 page(s

Preoperative abdominal muscle elongation with botulinum toxin A for complex incisional ventral hernia repair

Background: Surgical repair of recurrent abdominal incisional hernia(s) can be challenging due to complex operative conditions, intense post-operative pain, potential respiratory compromise and lateral muscle traction predisposing to early recurrence. We report our preliminary results with botulinum toxin A (BTA) injection causing flaccid paralysis (relaxation) of the lateral abdominal wall muscles prior to surgery. Methods: A prospective pilot study measured the effect of preoperative BTA prior to elective repair of recurrent abdominal hernias. Under ultrasound control, 2 weeks prior to surgery, 50 units of BTA was injected into the external oblique, internal oblique and transversus abdominis muscles at three sites on each side of the lateral abdominal wall (total dose 300 units). Pre- and post-BTA abdominal computed tomography measured changes in abdominal wall muscle thickness and length. All hernias were repaired with laparoscopic or laparoscopic-assisted mesh techniques in a single or two-staged procedure. Results: Eight patients received BTA injections which were tolerated with no complications. Post-BTA preoperative computed tomography showed a significant increase in mean length of lateral abdominal wall from 18.5cm pre-BTA to 21.3cm post-BTA (P = 0.017) with a mean unstretched length gain of 2.8cm per side (range 0.8-6.0cm). All hernias were surgically reduced with mesh with no early recurrence. Conclusion: Preoperative BTA injection prior to complex abdominal hernia repair is a safe procedure that causes flaccid relaxation, elongation and thinning of the lateral abdominal muscles and decrease in hernia defect. Although further evaluation is required, BTA injections may be a useful adjunct to surgical repair of complex incisional hernias