Honghua Hu

Bacterial Biofilm Infection Detected in Breast Implant-Associated Anaplastic Large-Cell Lymphoma.

Background: A recent association between breast implants and the development of anaplastic large-cell lymphoma (ALCL) has been observed. The purpose of this study was to identify whether bacterial biofilm is present in breast implant–associated ALCL and, if so, to compare the bacterial microbiome to nontumor capsule samples from breast implants with contracture. Methods: Twenty-six breast implant–associated ALCL samples were analyzed for the presence of biofilm by real-time quantitative polymerase chain reaction, next-generation sequencing, fluorescent in situ hybridization, and scanning electron microscopy, and compared to 62 nontumor capsule specimens. Results: Both the breast implant–associated ALCL and nontumor capsule samples yielded high mean numbers of bacteria (breast implant–associated ALCL, 4.7 × 106 cells/mg of tissue; capsule, 4.9 × 106 cells/mg of tissue). Analysis of the microbiome in breast implant–associated ALCL specimens showed significant differences with species identified in nontumor capsule specimens. There was a significantly greater proportion of Ralstonia spp. present in ALCL specimens compared with nontumor capsule specimens (p < 0.05). In contrast, significantly more Staphylococcus spp. were found associated with nontumor capsule specimens compared with breast implant–associated ALCL specimens (p < 0.001). Bacterial biofilm was visualized both on scanning electron microscopy and fluorescent in situ hybridization. Conclusions: This novel finding of bacterial biofilm and a distinct microbiome in breast implant–associated ALCL samples points to a possible infectious contributing cause. Breast implants are widely used in both reconstructive and aesthetic surgery, and strategies to reduce their contamination should be more widely studied and practiced. CLINICAL QUESTION/LEVEL OF EVIDENCE: Risk, V.

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. CLINICAL QUESTION/LEVEL OF EVIDENCE: Risk, V.

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 × 108 bacteria/g; smooth: 3.00 × 108 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 < 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.

Prevention of Biofilm-Induced Capsular Contracture With Antibiotic-Impregnated Mesh in a Porcine Model

BACKGROUND A growing body of evidence implicates subclinical (biofilm) infection around breast implants as an important cause of capsular contracture (CC). OBJECTIVES The authors use an in vivo porcine model to investigate the potential of antibiotic-impregnated mesh as a prophylactic measure against biofilm formation and CC. METHODS A total of 28 implants (14 untreated controls, 14 treated with antibiotic mesh) were inserted into 5 adult female pigs. All implants and pockets were inoculated with a human clinical strain of Staphylococcus epidermidis. The implants were left in situ for 16 weeks and then analyzed for contracture using both Baker grading and applanation tonometry. The presence of biofilm infection was assessed by subsequent microbiological analysis of implants and capsules. RESULTS One untreated implant had extruded and was excluded from analysis. The tissue surrounding the 13 untreated control implants had Baker Grade III/IV CC, whereas no CC was identified around the 14 antibiotic mesh-treated implants. This difference was highly significant (P < .001). Tonometry findings were consistent with the Baker assessments. Although bacterial biofilm was detected on all implants and capsules, the biofilms on the antibiotic-treated implants and surrounding capsules were generally single-layered or isolated in contrast to the multilayer biofilms found on untreated implants and capsules. CONCLUSIONS Based on the findings from this study of a porcine model, the use of antibiotic-impregnated mesh reduces bacterial access to breast implants at the time of surgical insertion and may subsequently protect against subclinical infection and CC.

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

Abstract Background Most of the worlds bacteria live in biofilms, three-dimensional clusters attached to surfaces.Manyhospital-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.

A new dry-surface biofilm model: An essential tool for efficacy testing of hospital surface decontamination procedures.

UNLABELLED The environment has been shown to be a source of pathogens causing infections in hospitalised patients. Incorporation of pathogens into biofilms, contaminating dry hospital surfaces, prolongs their survival and renders them tolerant to normal hospital cleaning and disinfection procedures. Currently there is no standard method for testing efficacy of detergents and disinfectants against biofilm formed on dry surfaces. AIM The aim of this study was to develop a reproducible method of producing Staphylococcus aureus biofilm with properties similar to those of biofilm obtained from dry hospital clinical surfaces, for use in efficacy testing of decontamination products. The properties (composition, architecture) of model biofilm and biofilm obtained from clinical dry surfaces within an intensive care unit were compared. METHODS The CDC Biofilm Reactor was adapted to create a dry surface biofilm model. S. aureus ATCC 25923 was grown on polycarbonate coupons. Alternating cycles of dehydration and hydration in tryptone soy broth (TSB) were performed over 12 days. Number of biofilm bacteria attached to individual coupons was determined by plate culture and the coefficient of variation (CV%) calculated. The DNA, glycoconjugates and protein content of the biofilm were determined by analysing biofilm stained with SYTO 60, Alexa-488-labelled Aleuria aurantia lectin and SyproOrange respectively using Image J and Imaris software. Biofilm architecture was analysed using live/dead staining and confocal microscopy (CM) and scanning electron microscopy (SEM). Model biofilm was compared to naturally formed biofilm containing S. aureus on dry clinical surfaces. RESULTS The CDC Biofilm reactor reproducibly formed a multi-layered, biofilm containing about 10(7) CFU/coupon embedded in thick extracellular polymeric substances. Within run CV was 9.5% and the between run CV was 10.1%. Protein was the principal component of both the in vitro model biofilm and the biofilms found on clinical surfaces. Continued dehydration and ageing of the model biofilm for 30 days increased the % of protein, marginally decreased gylcoconjugate % but reduced extracellular DNA by 2/3. The surface of both model and clinical biofilms was rough reflecting the heterogeneous nature of biofilm formation. The average maximum thickness was 30.74±2.1 μm for the in vitro biofilm model and between 24 and 47 μm for the clinical biofilms examined. CONCLUSION The laboratory developed biofilm was similar to clinical biofilms in architecture and composition. We propose that this method is suitable for evaluating the efficacy of surface cleaners and disinfectants in removing biofilm formed on dry clinical surfaces as both within run and between run variation was low, and the required equipment is easy to use, cheap and readily available.

Effect of cadexomer iodine on the microbial load and diversity of chronic non-healing diabetic foot ulcers complicated by biofilm in vivo

Abstract Objectives: The performance of cadexomer iodine was determined against microbial populations from chronic non-healing diabetic foot ulcers (DFUs) complicated by biofilm in vivo, using molecular, microscopy and zymography methods. Methods: Chronic non-healing DFUs due to suspected biofilm involvement were eligible for enrolment. DNA sequencing and real-time quantitative PCR was used to determine the microbial load and diversity of tissue punch biopsies obtained pre- and post-treatment. Scanning electron microscopy and/or fluorescence in situ hybridization confirmed the presence or absence of biofilm. Zymography was used to determine levels of wound proteases. Results: Seventeen participants were recruited over a 6 month period. Scanning electron microscopy and or fluorescence in situ hybridization confirmed the presence of biofilm in all samples. Eleven participants exhibited log10 reductions in microbial load after treatment (range 1–2 log10) in comparison with six patients who experienced <1 log10 reduction (P = 0.04). Samples were tested for levels of wound proteases pre- and post-treatment. Reductions in the microbial load correlated to reductions in wound proteases pre- and post-treatment (P = 0.03). Conclusions: To the best of our knowledge, this study represents the first in vivo evidence, employing a range of molecular and microscopy techniques, of the ability of cadexomer iodine to reduce the microbial load of chronic non-healing DFUs complicated by biofilm. Further analyses correlating log reductions to optimal duration of therapy and improvements in clinical parameters of wound healing in a larger cohort are required.

Hypochlorous Acid Versus Povidone-Iodine Containing Irrigants: Which Antiseptic is More Effective for Breast Implant Pocket Irrigation?

Background Capsular contracture induced by chronic subclinical infection is a major cause of poor outcomes and reoperation in breast implant surgery. The use of pocket irrigation with antiseptic/antibiotic has been shown to reduce the incidence of contracture. A new formulation of hypochlorous acid solution PhaseOne has been proposed as potential agent for irrigation. Objectives This study aimed to test the efficacy of hypochlorous acid solution PhaseOne for use in breast pocket irrigation as an alternative to povidone iodine solution Betadine. Methods The efficacy of PhaseOne, a hypochlorous acid formulated wound and skin cleanser, was tested in vitro against planktonic and biofilm Staphylococcus aureus with or without biological soil and in an implant attachment assay. Its activity was compared with Betadine containing 10% povidone iodine. Results Our findings showed that PhaseOne was unable to eradicate planktonic and/or biofilm S. aureus in the presence of either tryptone soy broth or bovine calf serum (protein soil) in a variety of in vitro assays. Conclusions We advise that povidone iodine containing irrigants are superior to hypochlorous acid containing irrigants in the clinical setting and should remain the recommended solution for pocket irrigation to reduce bacterial contamination at breast implants surgery.

Next generation DNA sequencing of tissues from infected diabetic foot ulcers

We used next generation DNA sequencing to profile the microbiome of infected Diabetic Foot Ulcers (DFUs). The microbiota was correlated to clinical parameters and treatment outcomes to determine if directed antimicrobial therapy based on conventional microbiological cultures are relevant based on genomic analysis. Patients ≥ 18 years presenting with a new Diabetic Foot Infection (DFI) who had not received topical or oral antimicrobials in the two weeks prior to presentation, were eligible for enrolment. Tissue punch biopsies were obtained from infected DFUs for analysis. Demographics, clinical and laboratory data were collected and correlated against microbiota data. Thirty-nine patients with infected DFUs were recruited over twelve-months. Shorter duration DFUs (< six weeks) all had one dominant bacterial species (n = 5 of 5, 100%, p < 0.001), Staphylococcus aureus in three cases and Streptococcus agalactiae in two. Longer duration DFUs (≥ six weeks) were diversely polymicrobial (p < 0.01) with an average of 63 (range 19–125) bacterial species. Severe DFIs had complex microbiomes and were distinctly dissimilar to less severe infections (p = 0.02), characterised by the presence of low frequency microorganisms. Nineteen patients (49%) during the study period experienced antimicrobial treatment failure, but no overall differences existed in the microbiome of patients who failed therapy and those who experienced treatment success (p = 0.2). Our results confirm that short DFUs have a simpler microbiome consisting of pyogenic cocci but chronic DFUs have a highly polymicrobial microbiome. The duration of a DFU may be useful as a guide to directing antimicrobial therapy.

Characterization of microbial community composition, antimicrobial resistance and biofilm on intensive care surfaces

BACKGROUND Organisms causing healthcare associated infections can be sourced from the inanimate environment around patients. Residing in a biofilm increases the chances of these organisms persisting in the environment. We aimed to characterise bacterial environmental contamination, genetically and physiologically, and relate this to general intensive care unit (ICU) cleanliness. METHODS Cleanliness was determined by adenosine triphosphate (ATP) measurements of 95 high-touch objects. Bacteriological samples were obtained from the same sites (n=95) and from aseptically removed sections (destructive samples, n=20). Bacterial enrichment culture was conducted using tryptone soya broth prior to plating on horse blood agar, MacConkey agar, and screening chromogenic agar for identification of multidrug resistance organism (MDRO). Bacterial load and microbial diversity were determined using quantitative PCR (qPCR) and next generation DNA sequencing respectively. Confocal laser scanning microscopy and scanning electron microscopy were used to visually confirm the biofilm presence. RESULTS Many intensive care surfaces (61%) were highly contaminated by biological soil as determined by ATP bioluminescence testing. The degree of biological soiling was not associated with bacterial contamination as detected by qPCR. Bacterial load ranged from 78.21 to 3.71×108 (median=900) bacteria/100cm2. Surface swabs from 71/95 sites (75%) were culture-positive; of these 16 (22.5%) contained MDRO. The most abundant genera were Staphylococcus, Propionibacterium, Pseudomonas, Bacillus, Enterococcus, Streptococcus and Acinetobacter. Biofilm was visually confirmed by microscopy on 70% (14/20) of items. CONCLUSION Bacterial biofilms and MDROs were found on ICU surfaces despite regular cleaning in Saudi Arabia, suggesting that biofilm development is not controlled by current cleaning practices.