"Race for the Surface" : Competition between Bacteria and Host Cells in Implant Colonization Process

Prosthetic infection represents a major problem in the outcome of patients after implantation of a foreign body. The presence of biomaterial in the body provides a substratum to host either tissue-cell integration or bacterial colonization. In obliteration of an infected bone, artificial bone substitutes and rigid fixation materials are usually necessary to fill bone cavity and to restore the properties of the bone respectively. This study attempted to discover the effect of bioactive glass bone substitute granules (BAG) S53P4 on bacterial and human-cell adhesion on other implant used simultaneously (I, II). During development of new infection-resistant biomaterials, adherence and colonization of either bacterial cells or tissue cells on biomaterials must be evaluated in parallel. A methodology allowing study of the simultaneous growth of bacteria and tissue cells on the same biomaterial surface was developed. This will allow discovery of the effect of various bacterial concentrations on host-cell viability and integration with an implant surface, and their relation to increasing reactive oxygen species (ROS) levels and cell apoptosis (III). Finally, considering our first results and that microorganisms frequently infect an implant surface during surgery and start to compete for the surface before tissue integration, it was hypothesized that incubation of implants with host cells before implantation may be one way to reduce the bacterial living space available and would prevent bacterial adhesion and consequently the infection of biomaterials (IV). Bacterial and human osteoblast-like osteosarcoma cells (SaOS-2) or primary osteoblast (hOB) cells were incubated for 4.5 hours, 2 days, or 4 days at 37°C. As substratum, titanium (Ti), polytetrafluoroethylene (PTFE), polydimethyl-siloxane (PDMS), or bioactive glass plates (IV) were used. The study was done separately (I, II), in competition with SaOS-2 or hOB (III), or in competition with SaOS-2 after 24-hour pre-incubation with SaOS-2 (IV). The effect of BAG S53P4 on bacteria (I) and cell (II) adhesion was studied in either a normal atmosphere or in hypoxia-simulating atmospheric conditions of the middle ear, mastoid cavity, or sinuses. Human osteoblast-like SaOS-2 cells or primary osteoblast (hOB) cells (III) (both, 1x105cells/mL), and collection strains of Staphylococcus aureus and Staphylococcus epidermidis (I) [108 colony forming units (CFU) (I) or (serial 1:10 dilutions of 108 CFU (III, IV)] were employed. The bacteria and cell proliferation, cytotoxicity (III, IV), and production of reactive oxygen species (ROS) (III) were evaluated by colorimetric (MTT, LDH, and crystal violet) (III, IV) as well as by fluorometric methods (fluorescent microscopy and flow cytometry) (III). Bacterial cell viability was studied by use of a drop-plate method after sonication. Effects of BAG S53P4 on cell adhesion were linked intimately with modifications of cellular attachment organs (vinculin containing focal adhesions), rearrangement of the actin cytoskeleton, and cellular spreading. The presence of bioglass under normoxic and hypoxic conditions prevented bacterial and biofilm adhesion for most of the materials and promoted integration of SaOS-2 cells with various biomaterial surfaces, especially under hypoxic conditions, in which S53P4 granules cause increased pH (I, II). In the competitive study, the presence of bacteria resulted in reduced adherence of human cells to the surface of the biomaterials, increased production of ROS, and increased apoptosis. The presence of either type of human cell was associated with a reduction in bacteria compared with that for the materials incubated with S. aureus only (III). Pretreatment with human cells was also associated with a reduction in bacterial colonization of the biomaterial compared with that of the non-pretreated materials, but the presence of bacteria produced a decrease in viable human cells for all materials (IV). In conclusion, the presence of S53P4 granules may both protect implants from bacterial colonization and promote their osteointegration. In the presence of bacteria and cells, colonization of the surface by one reduces colonization by the other. The bacteria produce cellular oxidative stress in human cells, which may be related to the cellular death. The preoperative incubation of prostheses with host cells could be a new way to prevent infection of biomaterials and lessen the risk for bacterial antibiotic resistance

Investigación del estigma y las comorbilidades del paciente con Lepra

La Lepra ha sido y sigue siendo una enfermedad olvidada, infradiagnosticada y cargada de un gran estigma social, que influye en muchos aspectos de la vida de las personas afectadas, aisladas ante el rechazo, especialmente si padecen deformidades visibles. El objeto de este estudio busca ahondar en las historias de los pacientes con Lepra que residen en el Sanatorio de Fontilles, en la de sus familiares y el personal sanitario, profundizando en la vivencia de su estigma. Por otro lado, al ampliar el estudio a través de grupos de discusión, se analiza el conocimiento existente sobre Lepra, tanto de la sociedad como de otros profesionales sanitarios. Mientras la sociedad desconoce aspectos básicos de su transmisión, fundamentales para eliminar el estigma asociado a su padecimiento, los propios afectados que la han “superado”, evitan nombrarla y se aíslan entre los muros del leprosorio. Conseguir reducir el estigma contribuiría a superar las barreras existentes favoreciendo su prevención, tratamiento y diagnóstico precoz, evitando su progresión y en consecuencia la afectación de la vida social, económica y psicosocial de los enfermos y enfermas.Leprosy has been and still is an illness in oblivion, underdiagnosed and highly stigmatised in society whilst impacting the lives of people, -hence, being isolated by the rejection of society, especially when one suffers visible deformities. The main of this study is being enable to attain references of the sigma of patients diagnosed with Leprosy, relatives of the cited patients, as well as health worker working in the Sanatorium of Fontilles. In the meantime, expound basic knowledge of Leprosy comprehending two groups of discussion of society and others health workers helped to expand the stigma. Whilst society doesn ́t reckon the basics of Leprosy, those who have overcome the illness are still isolating themselves within the walls of the leper colony. Decrease of Leprosy stigma entails helping to destroy barriers based on prevention, treatment and support, which in turn enables access to early diagnosis. Such course of action would avoid the development of the disease and the social, economic and psychosocial impact in the lives of Leprosy patients and further foster their inclusion in society

Strategies to Prevent Biofilm Infections on Biomaterials: Effect of Novel Naturally-Derived Biofilm Inhibitors on a Competitive Colonization Model of Titanium by Staphylococcus aureus and SaOS-2 Cells

Biofilm-mediated infection is a major cause of bone prosthesis failure. The lack of molecules able to act in biofilms has driven research aimed at identifying new anti-biofilm agents via chemical screens. However, to be able to accommodate a large number of compounds, the testing conditions of these screenings end up being typically far from the clinical scenario. In this study, we assess the potential applicability of three previously discovered anti-biofilm compounds to be part of implanted medical devices by testing them on in vitro systems that more closely resemble the clinical scenario. To that end, we used a competition model based on the co-culture of SaOS-2 mammalian cells and Staphylococcus aureus (collection and clinical strains) on a titanium surface, as well as titanium pre-conditioned with high serum protein concentration. Additionally, we studied whether these compounds enhance the previously proven protective effect of pre-incubating titanium with SaOS-2 cells. Out of the three, DHA1 was the one with the highest potential, showing a preventive effect on bacterial adherence in all tested conditions, making it the most promising agent for incorporation into bone implants. This study emphasizes and demonstrates the importance of using meaningful experimental models, where potential antimicrobials ought to be tested for the protection of biomaterials in translational applications

Strategies to Prevent Biofilm Infections on Biomaterials: Effect of Novel Naturally-Derived Biofilm Inhibitors on a Competitive Colonization Model of Titanium by Staphylococcus aureus and SaOS-2 Cells

Biofilm-mediated infection is a major cause of bone prosthesis failure. The lack of molecules able to act in biofilms has driven research aimed at identifying new anti-biofilm agents via chemical screens. However, to be able to accommodate a large number of compounds, the testing conditions of these screenings end up being typically far from the clinical scenario. In this study, we assess the potential applicability of three previously discovered anti-biofilm compounds to be part of implanted medical devices by testing them on in vitro systems that more closely resemble the clinical scenario. To that end, we used a competition model based on the co-culture of SaOS-2 mammalian cells and Staphylococcus aureus (collection and clinical strains) on a titanium surface, as well as titanium pre-conditioned with high serum protein concentration. Additionally, we studied whether these compounds enhance the previously proven protective effect of pre-incubating titanium with SaOS-2 cells. Out of the three, DHA1 was the one with the highest potential, showing a preventive effect on bacterial adherence in all tested conditions, making it the most promising agent for incorporation into bone implants. This study emphasizes and demonstrates the importance of using meaningful experimental models, where potential antimicrobials ought to be tested for the protection of biomaterials in translational applications

Prevention of Biomaterial Infection by Pre-Operative Incubation with Human Cells

Background: Cells of tissues and biofilm forming bacteria compete for the living space on the surface of an implant. We hypothesized the incubation of the implant (titanium, polydimethylsiloxane, and polystyrene surface) with human cells before implantation as a strategy to prevent bacterial adhesion and biofilm formation. Methods: After 24 hours of incubation with human osteogenic sarcoma SaOS-2 cells (1x10(5) cells/mL), the materials were incubated for 4.5 hours or two days with Staphylococcus aureus in serial 1:10 dilutions of 10(8) colony-forming units/mL. The bacterial adherence and biofilm biomass on materials pre-incubated with SaOS-2 cells were compared with our previous results on materials incubated only with bacteria or in simultaneous co-culture of SaOS-2 cells and S. aureus. Fluorescent microscopy and crystal violet stain were used. The number of viable SaOS-2 and bacterial cells present was tested using colorimetric methods (MTT, LDH) and drop plate method, respectively. Results: The pre-treatment with human cells was associated with a reduction of bacterial colonization of the biomaterial at 4.5 hours and 48 hours compared with the non-pre-treated materials. The presence of bacteria decreased the number of viable human cells on all materials. (Supplementary Fig. 1; see online supplementary materials at www.liebertpub.com/sur). Conclusions: These results suggest that the pre-operative incubation of prostheses with host cells could prevent infection of biomaterials.Peer reviewe

Tinea nigra palmaris: a clinical case in a rural Ethiopian hospital

Tinea nigra is an infrequent, superficial fungal infection, mainly caused by Hortaea werneckii, which is still underreported in Ethiopia. An asymptomatic 62-year-old male patient sought a rural hospital of Ethiopia, showing dark plaques on the palms of both hands. A superficial mycosis was suspected and a direct light microscopic mycological examination from skin scrapings revealed short brownish hyphae. To our knowledge, this is the first case of tinea nigra from the Ethiopian highlands. This may be due to the actual rarity of the condition or to underreportin

Comparative evaluation of Panbio and SD Biosensor antigen rapid diagnostic tests for COVID-19 diagnosis

The aim of our study was to evaluate the diagnostic performance of two antigen rapid diagnostic tests (Ag‐RDTs) to diagnose severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) infection. We evaluated Panbio and SD‐Biosensor Ag‐RDTs. We employed 186 polymerase chain reaction (PCR) negative samples to evaluate the specificity and 170 PCR positive samples to assess the sensitivity. We evaluated their sensitivity according to Cycle threshold (Ct) values and days post onset of symptoms (d.p.o.). Tests were compared using the McNemar's test. Agreement was evaluated using the kappa score. Specificity was 100% for Panbio and 97.3% for SD‐Biosensor. Sensitivity for samples with Ct ≤ 20 was 100% for both assays and for samples with Ct = 20–25 was 93.0% (Panbio) and 95.3% (SD‐Biosensor) (p = 1.000). Sensitivity decreased for samples wit Ct = 25–30 (Panbio: 41.3%, SD‐Biosensor: 52.2%, p = 0.125) and samples with Ct ≥ 30 (Panbio: 5.0%, SD‐Biosensor: 17.5%, p = 0.063). Sensitivity within seven d.p.o. was 87.7% for Panbio and 90.4% for SD‐Biosensor and notably decreased after seven d.p.o. Agreement with PCR was excellent for high viral load samples (Ct ≤ 25): Panbio, 98.9%, kappa = 0.974; SD‐Biosensor, 97.4%, kappa = 0.940. Agreement between Ag‐RDTs was excellent (94.9%, kappa = 0.882). Panbio and SD‐Biosensor Ag‐RDTs showed excellent agreement and diagnostic performance results for samples with high viral loads (Ct ≤ 25) or samples within seven d.p.o

Use of an experimental model to evaluate infection resistance of meshes in abdominal wall surgery

Background: Staphylococcal species are the most common organisms causing prosthetic mesh infections, however, infections due to rapidly growing mycobacteria are increasing. This study evaluates the resistance of biomaterial for abdominal wall prostheses against the development of postoperative infection in a rat model. Material and methods: In 75 rats, we intramuscularly implanted three different types of prostheses: (1) low-density polypropylene monofilament mesh (PMM), (2) high-density PMM, and (3) a composite prosthesis composed of low-density PMM and a nonporous hydrophilic film. Meshes were inoculated with a suspension containing 108 colony-forming units of Staphylococcus aureus, Staphylococcus epidermidis, Mycobacterium fortuitum, or Mycobacterium abscessus before wound closure. Animals were sacrificed on the eighth day postoperatively for clinical evaluation, and the implants were removed for bacteriologic analyses. Results: Prostheses infected with S aureus showed a higher bacterial viability, worse integration, and clinical outcome compared with infection by other bacteria. Composite prostheses showed a higher number of viable colonies of both M fortuitum and Staphylococcus spp., with poorer integration in host tissue. However, when the composite prosthesis was infected with M abscessus, a lower number of viable bacteria were isolated and a better integration was observed compared with infection by other bacteria. Conclusions: Considering M abscessus, a smaller collagen-free contact surface shows better resistance to infection, however, depending on the type of bacteria, prostheses with a large surface, and covered with collagen shows reduced resistance to infection, worse integration, and worse clinical outcome. (C) 2016 Elsevier Inc. All rights reserved.Peer reviewe

Increased Prevalence of Symptomatic Human Intestinal Spirochetosis in MSM with High-Risk Sexual Behavior in a Cohort of 165 Individuals

Human intestinal spirochetosis (HIS) can cause gastrointestinal symptoms, although asymptomatic infections have been described. Individuals from low-income countries, people living with HIV, and men who have sex with men (MSM) show increased risk. A retrospective review of all patients diagnosed with HIS (n = 165) between January 2013 and October 2020 at a tertiary hospital in Madrid, Spain, was performed to assess risk factors for symptomatic HIS, symptoms, and response to treatment. Most patients were male (n = 156; 94.5%), 86.7% were MSM, and 23.5% practiced chemsex, of whom most were symptomatic (p = 0.039). Most patients (78.4%) reported unprotected oral-anal intercourse. A total of 124 (81.1%) were symptomatic; diarrhea was the most common complaint (68.3%). Multivariable regression showed increased odds of symptoms associated with age under 41 (odds ratio 5.44, 95% CI 1.87-15.88; p = 0.002). Colonoscopy was normal in 153 (92.7%). Furthermore, 66.7% presented previous or concomitant sexually transmitted diseases (STDs). Among the patients, 102 underwent testing for other gastrointestinal pathogens, with positive results in 20 (19.6%). All symptomatic patients without concomitant gastrointestinal infection presenting improvement on follow-up (42 of 53) had received either metronidazole or doxycycline (p = 0.049). HIS should be considered as a cause of chronic diarrhea in MSM with high-risk sexual behavior after other causes have been ruled out; treatment with metronidazole is recommended. Coinfection with other STDs is common.S

Presence and genetic diversity of enteric protists in captive and semi-captive non-human primates in côte d'Ivoire, Sierra Leone, and Peru

Little information is currently available on the occurrence and genetic diversity of pathogenic and commensal protist species in captive and semi-captive non-human primates (NHP) resident in zoological gardens or sanctuaries in low- and medium-income countries. In this molecular-based study, we prospectively collected individual faecal samples from apparently healthy NHP at the Abidjan Zoological Garden (AZG) in Côte d'Ivoire, the Tacugama Sanctuary (TS) in Sierra Leone, and the Quistococha Zoological Garden (QZG) in Peru between November 2018 and February 2020. We evaluated for the presence of pathogenic (Cryptosporidium spp., Entamoeba histolytica, Giardia duodenalis, Blastocystis sp., Enterocytozoon bieneusi, Balantioides coli) and commensal (Entamoeba dispar, Troglodytella abrassarti) protist species using PCR methods and Sanger sequencing. Giardia duodenalis was the most prevalent species found (25.9%, 30/116), followed by Blastocystis sp. (22.4%, 26/116), and E. dispar (18.1%, 21/116). We detected E. bieneusi (4.2%, 1/24) and T. abrassarti (12.5%, 3/24) only on NHP from AZG. Cryptosporidium spp., E. histolytica, and B. coli were undetected at the three sampling sites investigated here. Sequence analyses revealed the presence of zoonotic sub-assemblages BIII (n = 1) in AZG and BIV (n = 1) in TS within G. duodenalis. We identified Blastocystis subtype ST3 (100%, 6/6) in AZG, ST1 (80.0%, 12/15), ST2 (6.7%, 1/15), and ST3 (13.3%, 2/15) in TS, and ST2 (80.0%, 4/5) and ST3 (20.0%, 1/5) in QZG. The only E. bieneusi isolate detected here was identified as zoonotic genotype CAF4. Our PCR-based data indicate that potentially pathogenic protist species including G. duodenalis, Blastocystis sp., E. bieneusi, and B. coli are present at variable rates in the three NHP populations investigated here. The identification of zoonotic genotypes within these species indicates that human-NHP transmission is possible, although the extent and directionality of these events need to be elucidated in future molecular surveys.This study was funded by the Health Institute Carlos III (ISCIII), Spanish Ministry of Economy and Competitiveness under project PI16CIII/00024. David González-Barrio is the recipient of a ‘Sara Borrell’ postdoctoral fellowship (CD19CIII/00011) funded by the Spanish Ministry of Science, Innovation and Universities. Alejandro Dashti is the recipient of a PFIS contract (FI20CIII/00002) funded by the Spanish Ministry of Science and Innovation and Universities.S