Are late hernia mesh complications linked to Staphylococci biofilms?

Published online: 14 March 2022Purpose: The purpose of this study was to investigate the link between bacterial biofilms and negative outcomes of hernia repair surgery. As biofilms are known to play a role in mesh-related infections, we investigated the presence of biofilms on hernia meshes, which had to be explanted due to mesh failure without showing signs of bacterial infection. Methods: In this retrospective observational study, 20 paraffin-embedded tissue sections from explanted groin hernia meshes were analysed. Meshes have been removed due to chronic pain, hernia recurrence or mesh shrinkage. The presence and bacterial composition of biofilms were determined. First, specimens were stained with fluorescence in situ hybridisation (FISH) probes, specific for Staphylococcus aureus and coagulase-negative staphylococci, and visualised by confocal laser scanning microscopy. Second, DNA was extracted from tissue and identified by S. aureus and S. epidermidis specific PCR. Results: Confocal microscopy showed evidence of bacterial biofilms on meshes in 15/20 (75.0%) samples, of which 3 were positive for S. aureus, 3 for coagulase-negative staphylococci and 9 for both species. PCR analysis identified biofilms in 17/20 (85.0%) samples, of which 4 were positive for S. aureus, 4 for S. epidermidis and 9 for both species. Combined results from FISH/microscopy and PCR identified staphylococci biofilms in 19/20 (95.0%) mesh samples. Only 1 (5.0%) mesh sample was negative for bacterial biofilm by both techniques. Conclusion: Results suggest that staphylococci biofilms may be associated with hernia repair failure. A silent, undetected biofilm infection could contribute to mesh complications, chronic pain and exacerbation of disease.P. Patiniott, A. Jacombs, L. Kaul, H. Hu, M. Warner, B. Klosterhalfen, A. Karatassas, G. Maddern, K. Richte

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 A thymine residue in the wallaroo at position 358 in exon 5 has been replaced by a cytosine residue in the euro, which accounts for the previously reported electrophoretic difference between the two subspecies.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

Biofilms and effective porosity of hernia mesh: are they silent assassins?

PURPOSE:The purpose of this paper is to communicate two new concepts with the potential to cause major morbidity in hernia repair, effective porosity and biofilm. These 2 concepts are interrelated and have the potential to result in mesh-related complications. Effective porosity is a term well described in the textile industry. It is best defined as the changes to pore morphology after implantation of mesh in situ. It is heavily dependent on mesh construct and repair technique and has the potential to impact hernia repair by reducing mesh tissue integration and promoting fibrosis. Bacterial biofilm is a well-described condition affecting prosthesis in breast and join replacement surgery with catastrophic consequences. There is a paucity of information on bacterial biofilm in mesh hernia repair. We speculate that bacterial biofilm has the potential to reduce the effective porosity of mesh, resulting in non-suppurative mesh-related complications as well as the potential for late suppurative infections. We describe the aetiology, pathogenesis, diagnosis, treatment and preventative measures to address bacterial biofilm in mesh hernia surgery. Hernia surgeons should be familiar with these two new concepts which have the potential to cause major morbidity in hernia repair and know how to address them. METHODS:Ovid Medline and PubMed were searched for communications on "effective porosity" and "bacterial biofilm". RESULTS:There is a paucity of information in the literature of these conditions and their impact on outcomes following mesh hernia repair. CONCLUSIONS:We discuss the two concepts of effective porosity and biofilm and propose potential measures to reduce mesh-related complications. This includes choosing mesh with superior mesh construct and technical nuances in implanting mesh to improve effective porosity. Furthermore, measures to reduce bacterial biofilm and its consequences are suggested.A. S. W. Jacombs, A. Karatassas, B. Klosterhalfen, K. Richter, C. Hensma

The Use of Botulinum toxin A elongates the lateral abdominal wall prior to surgery for giant complex ventral hernias and may replace component separation

Introduction: Complex ventral hernias occur in up to 15% of patients undergoing abdominal surgery. 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. Reported recurrence rates, within 36 months vary between 15-21% for open repair and 7-15.5% for laparoscopic repair and as high as 56%, 47% and 48% after first, second and third hernia repairs. Despite innovation in surgical techniques, such as the introduction of surgical mesh and component separation, there have been minimal improvements in post-operative morbidity and hernia recurrence. Botulinum toxin type A (BTA), a neuromodulating agent, increasingly used for various clinical applications including dystonia, spasticity, cerebral palsy, hyperhidrosis, hypersalivation, bladder dysfunction, skin wrinkles and pain management over the last 40 years. There are now a few case reports, in humans and animals, using BTA for the peri-operative management in abdominal wall surgery with the aims of: I) improving analgesia, 2) using the flaccid paralysis to lengthen abdominal oblique muscles and facilitate apposition of the edges of the defect akin to the effect of component separation but without disrupting the fascial integrity and 3) decreasing lateral traction and thus reducing tension before and after surgical repair. Methods: A prospective pilot study measured the effect of preoperative BTA prior to elective repair of complex recurrent ventral hernias. Each patient received 300 untis of BTA injected in equal divided doses into the external oblique, internal oblique and transversus abdominis muscles at three sites on each side of the lateral abdominal wall (each dose 50 units). The six injections were performed in an outpatient setting under ultrasound control two weeks prior to surgery. Pre and post-BTA abdominal computed tomography (CT) measured changes in abdominal wall muscle thickness and length of the hernia defects. All hernias were subsequently repaired with laparoscopic (IPOM) or laparoscopic assisted mesh techniques in a one- or two-staged procedure with Sepramesh™ (Bard, Cranston RI, USA). Results: We report our initial 12 patients (lOM:2F), who underwent preoperative BTA prior to laparoscopic hernia repair between November 2012 and October 2014. The mean age was 59 years (range 32-83yrs) with mean defect size of 14.4 cm (range 7-28 cm, maximal linear defect). BTA injections were tolerated by all patients with no complications and they resumed normal activities between the injections and surgery. Comparison between pre and post-BTA injection abdominal CT scans demonstrated a mean unstretched lengthening of lateral abdominal muscle of 2.9 cm/side (range 0.7-5.9cm), thinning of7.3 mm (range 0.4-14.3mm). CT imaging also demonstrated reduction in loss of domain and reduction of abdominal hernia contents into the abdominal cavity in 12 patients prior to surgery. All the hernias were successfully reduced using standard laparoscopic or laparoscopic assisted techniques with surprising ease at the time of surgery without any fascial separation. There have been no post-operative recurrences, to date. The only side effect of BTA injections was the feeling of "bloatedness', day 4-day 5 post-injection, and increase abdominal girth, as reported by patient. Conclusion: Pre-operative BTA injection prior to complex abdominal hernia repair was a safe procedure that resulted in flaccid paralysis, unstretched elongation and thinning of the lateral abdominal muscles and decrease in loss of domain and hernia defect prior to surgery. We hypothesise that the flaccid paralysis of the lateral abdominal wall, due to pre-operative BTA, decreases lateral traction to enable: I) reduction of hernia defect at time of surgery, 2) decreases tension through the repair, for the first 2 months or more, during the critical healing phase and 3) may reduce the need for component separation.2 page(s

Assessment of the selection process for myocutaneous flap repair and surgical complications in pelvic exenteration surgery

Background: This study aimed to explore and quantify the selection process to guide the decision on closure type (myocutaneous flap repair (MFR) or primary closure) for people undergoing pelvic exenteration. Methods: This was a retrospective analysis of a prospectively maintained database with review of hospital records for verification and capture of missing data. Associations between four risk factors (previous radiotherapy, previous abdominoperineal resection, need for total exenteration, need for sacrectomy) were assessed individually and collectively as predictors of closure type and wound complications. Results: A total of 203 pelvic exenteration procedures were reviewed (75 primary and 122 recurrent cancers). Thirty-nine patients (19·2 per cent) had MFR and 164 (80·8 per cent) primary closure. Patients who had MFR were significantly more likely to exhibit each risk factor, confirming the selective decision process. MFR had higher rates of complications across all four risk factors, individually and combined. In the primary closure group, there was a significant correlation between the number of risk factors and the proportion of patients with a complication (r = 0·25, P = 0·008). In contrast, no such relationship was found for the MFR group (r = 0·01, P = 0·973). Among patients who had any complication, the primary closure group had significantly lower rates of any wound dehiscence (15 of 64 versus 17 of 28; P < 0·001) and total infection (16 of 64 versus 14 of 28; P = 0·019) compared with the MFR group. Conclusion: Rates of wound and septic complications after pelvic exenteration were low in patients with fewer than two risk factors who had a primary closure. MFR had significantly higher complication rates, and should be reserved for patients with two or more risk factors or extensive skin involvement.7 page(s

Intensive care unit environmental surfaces are contaminated by multidrug-resistant bacteria in biofilms : combined results of conventional culture, pyrosequencing, scanning electron microscopy, and confocal laser microscopy

Background: Hospital-associated infections cause considerable morbidity and mortality, and are expensive to treat. Organisms causing these infections can be sourced from the inanimate environment around a patient. Could the difficulty in eradicating these organisms from the environment be because they reside in dry surface biofilms? Aim: The intensive care unit (ICU) of a tertiary referral hospital was decommissioned and the opportunity to destructively sample clinical surfaces was taken in order to investigate whether multidrug-resistant organisms (MDROs) had survived the decommissioning process and whether they were present in biofilms. Methods: The ICU had two 'terminal cleans' with 500 ppm free chlorine solution; items from bedding, surrounds, and furnishings were then sampled with cutting implements. Sections were sonicated in tryptone soya broth and inoculated on to chromogenic plates to demonstrate MDROs, which were confirmed with the Vitek2 system. Genomic DNA was extracted directly from ICU samples, and subjected to polymerase chain reaction (PCR) for femA to detect Staphylococcus aureus and the microbiome by bacterial tag-encoded FLX amplicon pyrosequencing. Confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM) were performed on environmental samples. Findings: Multidrug-resistant bacteria were cultured from 52% (23/44) of samples cultured. S. aureus PCR was positive in 50%. Biofilm was demonstrated in 93% (41/44) of samples by CLSM and/or SEM. Pyrosequencing demonstrated that the biofilms were polymicrobial and contained species that had multidrug-resistant strains. Conclusion: Dry surface biofilms containing MDROs are found on ICU surfaces despite terminal cleaning with chlorine solution. How these arise and how they might be removed requires further study.10 page(s

In vitro and in vivo investigation of the influence of implant surface on the formation of bacterial biofilm in mammary implants

BACKGROUND: Capsular contracture remains the most common complication following breast augmentation surgery, and evidence suggests that bacterial biofilm on the implant surface is responsible. The authors investigated whether the interaction of bacterial biofilm with implants independently determines progression to capsule formation. They also studied the rate of bacterial growth and adhesion to implants. METHODS: Sixteen adult female pigs had 121 breast implants inserted. Sixty-six implants - 23 smooth and 43 textured - were inoculated with a human strain of Staphylococcus epidermidis and received no other treatment. After an average period of 19 weeks, Baker grading was performed and implants were retrieved. For the in vitro study, samples underwent both quantitative bacterial analysis and imaging using confocal laser scanning and scanning electron microscopy. RESULTS: At explantation, there was no significant difference (p = 1.0) in the presence of capsular contracture (Baker grade III and IV) between smooth (83 percent) and textured implants (84 percent). Biofilm was confirmed on 60 of the 66 capsules. Capsules from smooth and textured implants had the same number of infecting bacteria (textured: 3.01 x10⁸ bacteria/g; smooth: 3.00 x10⁸ bacteria/g). In vitro, the surface of textured implants showed 11-, 43-, and 72-fold more bacteria at 2, 6, and 24 hours, respectively, compared with smooth implants (p &lt; 0.001). These findings were confirmed by imaging analysis. CONCLUSIONS: These results show that textured implants develop a significantly higher load of bacterial biofilm in comparison with smooth implants. Furthermore, in vivo, once a threshold of biofilm forms on either smooth or textured implant surfaces, there seems to be an equal propensity to progress to capsular contracture.10 page(s