Pathogenic Mechanisms and Host Interactions in Staphylococcus epidermidis Device-Related Infection

Catalase-positive Staphylococcus epidermidis based cryo-millineedle platform facilitates the photo-immunotherapy against colorectal cancer via hypoxia improvement

The synergistic anti-tumor impact of phototherapy and a cascading immune response are profoundly limited by hypoxia and a weakened immune response. Intravenous and intratumoral injection of therapeutic drugs also cause pain, rapid drug clearance and low utilization rates. Here, a novel cryo-millineedle platform for intratumoral delivery of a phototherapy system, S.epi@IR820, is developed in this work, combining the properties of Staphylococcus epidermidis (S. epidermidis) and IR820 for photo-immunotherapy of colorectal cancer. In this cryo-millineedle platform, S. epidermidis enhances the near-infrared absorption and light stability of IR820 and catalyzes the decomposition of H2O2 into O2 via an endogenous catalase to relieve tumor hypoxia, improve phototherapy and enhance immunogenic cell death (ICD). More interestingly, the native immunogenicity of S. epidermidis and ICD elicited by phototherapy achieved a potent anti-tumor immune response. To the best of our knowledge, this is the first study to utilize native S. epidermidis to relieve hypoxia and facilitate phototherapy. Both in vitro and in vivo experiments showed that the millineedle based phototherapy system can efficiently catalyse the decomposition of H2O2 into O2, facilitate phototherapeutic killing of CT26 tumor cells by S.epi@IR820 and enhance ICD, thus successfully activated the immune response and achieved the photo-immunotherapy against colorectal cancer. In conclusion, this study provides a novel strategy for enhanced anti-tumor efficiency of photo-immunotherapy, and develops an effective method for orthotopic administration of tumors.

Potential of training of anti-Staphylococcus aureus therapeutic phages against Staphylococcus epidermidis multidrug-resistant isolates is restricted by inter- and intra-sequence type specificity

Phage therapy appears to be a promising approach to tackle multidrug-resistant bacteria, including staphylococci. However, most anti-staphylococcal phages have been characterized in Staphylococcus aureus, while a limited number of studies investigated phage activity against S. epidermidis. We studied the potential of phage training to extend the host range of two types of anti-S. aureus phages against S. epidermidis isolates. The Appelmans protocol was applied to a mixture of Kayvirus and a mixture of Silviavirus phages repeatedly exposed to seven S. epidermidis strains representative of nosocomial-associated sequence types (ST), including the world-wide disseminated ST2. We observed increased activity only for the Kayvirus mixture against two of these strains (ST2 or ST35). Phage subpopulations isolated from the training mixture using these two strains (five/strain) exhibited different evolved phenotypes, active only against their isolation strain or strains of the same ST. Of note, 16/47 ST2 strains were susceptible to one of the groups of trained phages. A comparative genomic analysis of ancestral and trained phage genomes, conducted to identify potential bacterial determinants of such specific activity, found numerous recombination events between two of the three ancestors. However, a small number of trained phage genes had nucleotide sequence modifications impacting the corresponding protein compared to ancestral phages, two to four of them per phage genome being specific of each group of phage subpopulations exhibiting different host range. The results suggest that anti-S. aureus phages can be adapted to S. epidermidis isolates but with inter- and intra-ST specificity.ImportanceS. epidermidis is increasingly recognized as a threat for public health. Its clinical importance is notably related to multidrug resistance. Phage therapy is one of the most promising alternative therapeutic strategies to antibiotics. Nonetheless, only very few phages active against this bacterial species have been described. In the present study, we showed that phage training can be used to extend the host range of polyvalent Kayvirus phages within the Staphylococcus genera to include S. epidermidis species. In the context of rapid development of phage therapy, in vitro forced adaptation of previously characterized phages could be an appealing alternative to fastidious repeated isolation of new phages to improve the therapeutic potential of a phage collection.

Pentadecanoic Acid-Releasing PDMS: Towards a New Material to Prevent S. epidermidis Biofilm Formation

Microbial biofilm formation on medical devices paves the way for device-associated infections. Staphylococcus epidermidis is one of the most common strains involved in such infections as it is able to colonize numerous devices, such as intravenous catheters, prosthetic joints, and heart valves. We previously reported the antibiofilm activity against S. epidermidis of pentadecanoic acid (PDA) deposited by drop-casting on the silicon-based polymer poly(dimethyl)siloxane (PDMS). This material exerted an antibiofilm activity by releasing PDA; however, a toxic effect on bacterial cells was observed, which could potentially favor the emergence of resistant strains. To develop a PDA-functionalized material for medical use and overcome the problem of toxicity, we produced PDA-doped PDMS by either spray-coating or PDA incorporation during PDMS polymerization. Furthermore, we created a strategy to assess the kinetics of PDA release using ADIFAB, a very sensitive free fatty acids fluorescent probe. Spray-coating resulted in the most promising strategy as the concentration of released PDA was in the range 0.8-1.5 μM over 21 days, ensuring long-term effectiveness of the antibiofilm molecule. Moreover, the new coated material resulted biocompatible when tested on immortalized human keratinocytes. Our results indicate that PDA spray-coated PDMS is a promising material for the production of medical devices endowed with antibiofilm activity.

Complex Interactions between the Human Major Histocompatibility Complex (MHC) and Microbiota: Their Roles in Disease Pathogenesis and Immune System Regulation

The relationship between microbiota and the immune system is complex and characterized by the ways in which microbiota directs immune function interactions, both innate and acquired and also keeps activating the immune system throughout an individual's life. In this respect, the human Major Histocompatibility Complex (MHC, referred to as HLA in humans) plays a crucial role and is also established in self-defense against microbes by presenting microbial-derived peptides to the immune cells. However, this assumption has some unclear aspects that should be investigated. For example, how is the microbiota shaped by microbe species diversity, quantity and functions of the immune system, as well as the role and molecular mechanisms of the HLA complex during this process. There are autoimmune diseases related to both HLA and specific microbiota changes or alterations, many of which are mentioned in the present review. In addition, the HLA peptide presenting function should be put in a framework together with its linkage to diseases and also with HLA compatibility necessary for transplants to be successful. These are still quite an enigmatically statistical and phenomenological approach, but no firm pathogenic mechanisms have been described; thus, HLA's real functioning is still to be fully unveiled. After many years of HLA single-genes studies, firm pathogenesis mechanisms underlying disease linkage have been discovered. Finally, microbiota has been defined as conformed by bacteria, protozoa, archaea, fungi, and viruses; notwithstanding, endogenous viral sequences integrated into the human genome and other viral particles (obelisks) recently found in the digestive mucosa should be taken into account because they may influence both the microbiome and the immune system and their interactions. In this context, we propose to integrate these microbial-genetic particle components into the microbiome concept and designate it as "microgenobiota".

Diversity and saline-alkali resistance of Coleoptera endosymbiont bacteria in arid and semi-arid climate

Soil salinization usually occurs in arid and semi-arid climate areas from 37 to 50 degrees north latitude and 73 to 123 degrees east longitude. These regions are inhabited by a large number of Coleopteran insects, which play an important role in the ecological cycle. However, little is known about the endosymbiotic microbial taxa and their biological characteristics in these insects. A study of endosymbiotic microorganisms of Coleoptera from Xinjiang, a typical arid and inland saline area, revealed that endosymbiont bacteria with salinity tolerance are common among the endosymbionts of Coleoptera. Functional prediction of the microbiota analysis indicated a higher abundance of inorganic ion transporters and metabolism in these endosymbiont strains. Screening was conducted on the tolerable 11% NaCl levels of Brevibacterium casei G20 (PRJNA754761), and differential metabolite and proteins were performed. The differential metabolites of the strain during the exponential and plateau phases were found to include benzene compounds, organic acids, and their derivatives. These results suggest that the endosymbiotic microorganisms of Coleoptera in this environment have adaptive evolution to extreme environments, and this group of microorganisms is also one of the important resources for mining saline and alkaline-tolerant chassis microorganisms and high-robustness enzymes.

IMPORTANCE

Coleoptera insects, as the first largest order of insect class, have the characteristics of a wide variety and wide distribution. The arid and semi-arid climate makes it more adaptable. By studying the endosymbiont bacteria of Coleoptera insects, we can systematically understand the adaptability of endosymbiont bacteria to host and special environment. Through the analysis of endosymbiont bacteria of Coleoptera insects in different saline-alkali areas in arid and semi-arid regions of Xinjiang, it was found that bacteria in different host samples were resistant to saline-alkali stress. These results suggest that bacteria and their hosts co-evolved in response to this climate. Therefore, this study is of great significance for understanding the endosymbiont bacteria of Coleoptera insects and obtaining extremophile resources (Saline-alkali-resistant chassis strains with modification potential for the production of bulk chemicals and highly robust industrial enzymes).

Unveiling the Potential of Drain Tip Cultures: Impact on Surgical Site Infections in Implant-Based Breast Reconstruction

PURPOSE

Surgical site infections (SSIs) remain a concern after implant-based breast reconstruction, despite preventive measures. These infections can have serious consequences. This study evaluated the correlation between drain tip culture results and SSIs in this patient population.

METHODS

We analyzed data from patients who underwent implant-based breast reconstruction between July 2021 and May 2023. Drain tip cultures were collected, and any SSIs occurring within one month of surgery were documented. We then compared clinical data with the culture results.

RESULTS

A total of 263 drain tip cultures were included. Notably, none of the 61 patients who underwent tissue expander removal and implant insertion had positive cultures. However, among the 202 patients who received tissue expanders or direct-to-implant procedures, 11 (5.45%) had positive cultures, with a total of 12 SSIs identified. Importantly, five of the 11 culture-positive wounds developed SSIs. Multivariate analysis revealed a significant two-way association between infection and positive drain tip cultures. For Staphylococcus aureus specifically, drain tip cultures showed excellent predictive value: sensitivity (33.33%), specificity (100%), positive predictive value (100%), and negative predictive value (95.96%).

CONCLUSION

Drain tip cultures from immediate implant-based breast reconstructions significantly correlated with SSIs. Close monitoring is crucial, especially when S. aureus is identified in the culture.

Complete genome sequence of three Staphylococcus epidermidis strains isolated from patients with skin diseases in Japan

Staphylococcus epidermidis is a member of the human skin microbiota as a commensal organism but could be an important opportunistic pathogen for immunocompromised individuals. Here, we report the complete genome sequence of three S. epidermidis strains isolated from patients with skin diseases.

Three-Dimensional-Printed Modular Titanium Alloy Plates for Osteosynthesis of the Jawbone

BACKGROUNDS

The titanium-aluminum-vanadium alloy (Ti-6Al-4V) is frequently used in implantology due to its biocompatibility. The use of 3D printing enables the mechanical modification of implant structures and the adaptation of their shape to the specific needs of individual patients.

METHODS

The titanium alloy plates were designed using the 3D CAD method and printed using a 3D SLM printer. Qualitative tests were performed on the material surface using a microcomputed tomography scanner. The cytotoxicity of the modular titanium plates was investigated using the MTT assay on the L929 cell line and in direct contact with Balb/3T3 cells. Cell adhesion to the material surface was evaluated with hFOB1.19 human osteoblasts. Microbial biofilm formation was investigated on strains of Lactobacillus rhamnosus, Staphylococcus epidermidis, Streptococcus mutans and Candida albicans using the TTC test and scanning electron microscopy (SEM).

RESULTS

The surface analysis showed the hydrophobic nature of the implant. The study showed that the titanium plates had no cytotoxic properties. In addition, the material surface showed favorable properties for osteoblast adhesion. Among the microorganisms tested, the strains of S. mutans and S. epidermidis showed the highest adhesion capacity to the plate surface, while the fungus C. albicans showed the lowest adhesion capacity.

CONCLUSIONS

The manufactured modular plates have properties that are advantageous for the implantation and reduction in selected forms of microbial biofilm. Three-dimensional-printed modular titanium plates were investigated in this study and revealed the potential clinical application of this type of materials, regarding lack of cytotoxicity, high adhesion properties for osteoblasts and reduction in biofilm formation. The 3D CAD method allows us to personalise the shape of implants for individual patients.

Comprehensive genomic landscape of antibiotic resistance in Staphylococcus epidermidis

Staphylococcus epidermidis, a common commensal bacterium found on human skin, can cause infections in clinical settings, and the presence of antibiotic resistance genes (ARGs) impedes the treatment of S. epidermidis infections. However, studies characterizing the ARGs in S. epidermidis with regard to genomic and ecological diversities are limited. Thus, we performed a comprehensive and comparative analysis of 405 high-quality S. epidermidis genomes, including those of 35 environmental isolates from the Han River, to investigate the genomic diversity of antibiotic resistance in this pathogen. Comparative genomic analysis revealed the prevalence of ARGs in S. epidermidis genomes associated with multi-locus sequence types. The genes encoding dihydrofolate reductase (dfrC) and multidrug efflux pump (norA) were genome-wide core ARGs. β-Lactam class ARGs were also highly prevalent in the S. epidermidis genomes, which was consistent with the resistance phenotype observed in river isolates. Furthermore, we identified chloramphenicol acetyltransferase genes (cat) in the plasmid-like sequences of the six river isolates, which have not been reported previously in S. epidermidis genomes. These genes were identical to those harbored by the Enterococcus faecium plasmids and associated with the insertion sequence 6 family transposases, homologous to those found in Staphylococcus aureus plasmids, suggesting the possibility of horizontal gene transfer between these Gram-positive pathogens. Comparison of the ARG and virulence factor profiles between S. epidermidis and S. aureus genomes revealed that these two species were clearly distinguished, suggesting genomic demarcation despite ecological overlap. Our findings provide a comprehensive understanding of the genomic diversity of antibiotic resistance in S. epidermidis.

IMPORTANCE

A comprehensive understanding of the antibiotic resistance gene (ARG) profiles of the skin commensal bacterium and opportunistic pathogen Staphylococcus epidermidis needs to be documented from a genomic point of view. Our study encompasses a comparative analysis of entire S. epidermidis genomes from various habitats, including those of 35 environmental isolates from the Han River sequenced in this study. Our results shed light on the distribution and diversity of ARGs within different S. epidermidis multi-locus sequence types, providing valuable insights into the ecological and genetic factors associated with antibiotic resistance. A comparison between S. epidermidis and Staphylococcus aureus revealed marked differences in ARG and virulence factor profiles, despite their overlapping ecological niches.

Highly Cytocompatible Polylactic Acid Based Electrospun Microfibers Loaded with Silver Nanoparticles Generated onto Chestnut Shell Lignin for Targeted Antibacterial Activity and Antioxidant Action

Electrospun (e-spun) fibers are generally regarded as powerful tools for cell growth in tissue regeneration applications, and the possibility of imparting functional properties to these materials represents an increasingly pursued goal. We report herein the preparation of hybrid materials in which an e-spun d,l-polylactic acid matrix, to which chitosan or crystalline nanocellulose was added to improve hydrophilicity, was loaded with different amounts of silver(0) nanoparticles (AgNP) generated onto chestnut shell lignin (CSL) (AgNP@CSL). A solvent-free mechanochemical method was used for efficient (85% of the theoretical value by XRD analysis) Ag(0) production from the reduction of AgNO3 by lignin. For comparison, e-spun fibers containing CSL alone were also prepared. SEM and TEM analyses confirmed the presence of AgNP@CSL (average size 30 nm) on the fibers. Different chemical assays indicated that the AgNP@CSL containing fibers exhibited marked antioxidant properties (EC50 1.6 ± 0.1 mg/mL, DPPH assay), although they were halved with respect to those of the CSL containing fibers, as expected because of the efficient silver ion reduction. All the fibers showed high cytocompatibility toward human mesenchymal stem cells (hMSCs) representative of the self-healing process, and their antibacterial properties were tested against the pathogens Escherichia coli (E. coli), Staphylococcus epidermidis, and Pseudomonas aeruginosa. Finally, competitive surface colonization as simulated by cocultures of hMSC and E. coli showed that AgNP@CSL loaded fibers offered the cells a targeted protection from infection, thus well balancing cytocompatibility and antibacterial properties.

Differential survival of Staphylococcal species in macrophages

Staphylococcus aureus is considered an extracellular pathogen, yet the bacterium is able to survive within and escape from host cells. An agr/sae mutant of strain USA300 is unable to escape from macrophages but can replicate and survive within. We questioned whether such "non-toxic" S. aureus resembles the less pathogenic coagulase-negative Staphylococcal (CoNS) species like S. epidermidis, S. carnosus, S. lugdunensis, S. capitis, S. warneri, or S. pettenkoferi. We show that the CoNS are more efficiently killed in macrophage-like THP-1 cells or in human primary macrophages. Mutations in katA, copL, the regulatory system graRS, or sigB did not impact bacterial survival in THP-1 cells. Deletion of the superoxide dismutases impaired S. aureus survival in primary macrophages but not in THP-1 cells. However, expression of the S. aureus-specific sodM in S. epidermidis was not sufficient to protect this species from being killed. Thus, at least in those cells, better bacterial survival of S. aureus could not be linked to higher protection from ROS. However, "non-toxic" S. aureus was found to be insensitive to pH, whereas most CoNS were protected when phagosomal acidification was inhibited. Thus, species differences are at least partially linked to differences in sensitivity to acidification.

Unravelling staphylococcal small-colony variants in cardiac implantable electronic device infections: clinical characteristics, management, and genomic insights

Objectives

Staphylococcal small-colony variants (SCVs) are common in cardiac implantable electronic device (CIED) infections. This is the first retrospective and multi-case study on CIED infections due to staphylococcal SCVs, aiming to provide a theoretical basis for the clinical management of CIED and device-related infections caused by staphylococcal SCVs.

Methods

Ninety patients with culture positive CIED infections were enrolled between 2021 and 2022. We compared the demographic and clinical characteristics of patients with and without SCVs and performed genomic studies on SCVs isolates.

Results

Compared to patients without SCVs, those with SCVs had a longer primary pacemaker implantation time and were more likely to have a history of device replacement and infection. They showed upregulated inflammatory indicators, especially higher NEUT% (52.6 vs. 26.8%, P = 0.032) and they had longer hospital stays (median 13 vs. 12 days, P = 0.012). Comparative genomics analysis was performed on Staphylococcus epidermidis wild-type and SCVs. Some genes were identified, including aap, genes encoding adhesin, CHAP domain-containing protein, LPXTG cell wall anchor domain-containing protein, and YSIRK-type signal peptide-containing protein.

Conclusion

Staphylococcal SCVs affect the clinical characteristics of CIED infections. The process of staphylococcal SCVs adherence, biofilm formation, and interaction with neutrophils play a vital role.

The Use of the Taylor Spatial Frame in Treating Tibial Osteomyelitis Following Traumatic Tibial Fracture

Introduction

Tibial osteomyelitis can follow open fractures with bacteria colonising the wound and persisting through biofilm and sequestrum formation. The treatment is complex, requiring eradication through debridement before limb reconstruction, for which the Taylor spatial frame (TSF) is one option. This study evaluates patient outcomes after reconstruction and identifies factors associated with post-operative complications.

Materials and methods

Fifty-one cases of tibial osteomyelitis were treated by the Ilizarov technique from 2015 to 2021 at a major trauma centre. Bacterial samples and treatment factors were assessed. Patient outcomes were complication rates and time to bony union. Complications were expressed as odds-ratios (OR) with 95% confidence intervals. Linear regression was used to assess factors associated with time to union.

Results

The mean follow-up was 24.1 months with the mean time to radiological union being 11 months. Post-operative complications were noted in 76.5% of patients with pin-site infections most common (52.9%), followed by fracture malunion (29.4%). Smoking was associated with increased fracture malunion (OR = 4.148, 95% confidence Interval [1.13-15.18], p = 0.031). The time to union was positively associated with complications, age and time to full weight-bearing (FWB). All other measured factors were found not significant.

Conclusion

Tibial osteomyelitis is treated reliably by debridement and reconstruction using the Ilizarov technique using a TSF application. The most common complication was pin-site infection. Optimising patients through cessation of smoking and encouraging post-operative weight-bearing can reduce the complication rate and improve time to union.

Clinical significance

The Ilizarov technique using a TSF can treat significant deformities that result from the management of tibial osteomyelitis.

How to cite this article

Geetala R, Zhang J, Maghsoudi D, et al. The Use of the Taylor Spatial Frame in Treating Tibial Osteomyelitis Following Traumatic Tibial Fracture. Strategies Trauma Limb Reconstr 2024;19(1):32-35.

Employment of Spore-Forming Probiotics to Combat Persister Cells of Staphylococcus Epidermidis

Background

In this study, spore-forming probiotics were employed to eradicate Staphylococcus epidermidis biofilms and the presence and expression of genes involved in stress response was examined.

Methods

Polymerase chain reaction (PCR) assay was used to detect rpoS, relA and mazF genes in S. epidermidis ATCC 12228. Biofilm production was investigated by microtiter plate (MTP) assay. 100X minimum inhibitory concentration (MIC) of gentamycin was used to induce persister cells in planktonic and biofilm bacterial cells. The expression of rpoS, relA, and mazF genes was assessed at different time intervals of 2, 8, and 24 h using real-time PCR assay. Then, dilutions of 1, 0.5, and 0.25 µg/ml of the supernatant of Bacillus coagulans culture was used to eradicate the persister cells and the number of colonies was determined.

Results

Persister cells of S. epidermidis were formed after 7 h in planktonic and 5 h in the biofilm structure after exposure to 50 µg/ml of gentamycin. The expression of mazF and rpoS in biofilm structure and the expression of rpoS and relA in persister cells were significantly higher compared to the control (p< 0.05). The number of persister cells showed a reduction of log 2.4 and log 0.8 after exposure to 1 and 0.5 µg/ml B. coagulans supernatant, respectively, but no reduction was observed at the concentration of 0.25 µg/ml.

Conclusion

The results showed that the supernatant of probiotics containing their secretive metabolites can be used as a novel approach to combat persister cells.

Recent Progress in antibacterial hydrogel coatings for targeting biofilm to prevent orthopedic implant-associated infections

The application of orthopedic implants for bone tissue reconstruction and functional restoration is crucial for patients with severe bone fractures and defects. However, the abiotic nature of orthopedic implants allows bacterial adhesion and colonization, leading to the formation of bacterial biofilms on the implant surface. This can result in implant failure and severe complications such as osteomyelitis and septic arthritis. The emergence of antibiotic-resistant bacteria and the limited efficacy of drugs against biofilms have increased the risk of orthopedic implant-associated infections (OIAI), necessitating the development of alternative therapeutics. In this regard, antibacterial hydrogels based on bacteria repelling, contact killing, drug delivery, or external assistance strategies have been extensively investigated for coating orthopedic implants through surface modification, offering a promising approach to target biofilm formation and prevent OIAI. This review provides an overview of recent advancements in the application of antibacterial hydrogel coatings for preventing OIAI by targeting biofilm formation. The topics covered include: (1) the mechanisms underlying OIAI occurrence and the role of biofilms in exacerbating OIAI development; (2) current strategies to impart anti-biofilm properties to hydrogel coatings and the mechanisms involved in treating OIAI. This article aims to summarize the progress in antibacterial hydrogel coatings for OIAI prevention, providing valuable insights and facilitating the development of prognostic markers for the design of effective antibacterial orthopedic implants.

Community assembly of the human piercing microbiome

Predicting how biological communities respond to disturbance requires understanding the forces that govern their assembly. We propose using human skin piercings as a model system for studying community assembly after rapid environmental change. Local skin sterilization provides a 'clean slate' within the novel ecological niche created by the piercing. Stochastic assembly processes can dominate skin microbiomes due to the influence of environmental exposure on local dispersal, but deterministic processes might play a greater role within occluded skin piercings if piercing habitats impose strong selection pressures on colonizing species. Here we explore the human ear-piercing microbiome and demonstrate that community assembly is predominantly stochastic but becomes significantly more deterministic with time, producing increasingly diverse and ecologically complex communities. We also observed changes in two dominant and medically relevant antagonists (Cutibacterium acnes and Staphylococcus epidermidis), consistent with competitive exclusion induced by a transition from sebaceous to moist environments. By exploiting this common yet uniquely human practice, we show that skin piercings are not just culturally significant but also represent ecosystem engineering on the human body. The novel habitats and communities that skin piercings produce may provide general insights into biological responses to environmental disturbances with implications for both ecosystem and human health.

Infectious crystalline keratopathy following Descemet's stripping automated endothelial keratoplasty

INTRODUCTION

We describe this first case of Staphylococcus epidermidis causing infectious crystalline keratopathy (ICK) following Descemet stripping endothelial keratoplasty (DSAEK), that resolved after 5 weeks of topical antibiotic and corticosteroid treatment.

CASE DESCRIPTION

An 80-year-old woman presented with blurred vision, redness, and ocular pain 9 months after successful DSAEK. Slit lamp examination revealed the presence of white, non-suppurative, deep-branching stromal infiltrates, and a clinical diagnosis of ICK was made. Cultures of corneal scapings isolated multidrug-resistant Staphylococcus epidermidis. No subsequent surgical procedures were performed. Based on antibiotic sensitivity analysis, she was treated successfully with topical vancomycin and chloramphenicol for 5 weeks. Complete resolution of the infection with minor anterior stromal corneal scarring of the host cornea was noted after 5 weeks of treatment. This case report describes the diagnosis and management of ICK after DSAEK and reviews the relevant literature regarding the occurrence of ICK after DSAEK.

CONCLUSION

In this case, vancomycin and chloramphenicol allowed for the uncomplicated resolution of infection with only minor visual impairment from baseline.

Management of Biofilm with Breast Implant Surgery

LEARNING OBJECTIVES

After studying this article, the participant should be able to: 1. Understand how bacteria negatively impact aesthetic and reconstructive breast implants. 2. Understand how bacteria infect breast implants. 3. Understand the evidence associated with common implant infection-prevention strategies, and their limitations. 4. Understand why implementation of bacteria-mitigation strategies such as antibiotic administration or "no-touch" techniques may not indefinitely prevent breast implant infection.

SUMMARY

Bacterial infection of aesthetic and reconstructive breast implants is a common and expensive problem. Subacute infections or chronic capsular contractures leading to device explantation are the most commonly documented sequelae. Although bench and translational research underscores the complexities of implant-associated infection, high-quality studies with adequate power, control groups, and duration of follow-up are lacking. Common strategies to minimize infections use antibiotics-administered systemically, in the breast implant pocket, or by directly bathing the implant before insertion-to limit bacterial contamination. Limiting contact between the implant and skin or breast parenchyma represents an additional common strategy. The clinical prevention of breast implant infection is challenged by the clean-contaminated nature of breast parenchyma, and the variable behavior of not only specific bacterial species but also their strains. These factors impact bacterial virulence and antibiotic resistance.

Staphylococcus epidermidis bloodstream infections are a cause of septic shock in intensive care unit patients

OBJECTIVES

Staphylococcus epidermidis (SE) is a supposedly low-virulence agent, which may cause proven bloodstream infections (BSIs), with little-known consequences on intensive care unit (ICU) patients. We aimed at studying ICU patients diagnosed with BSIs caused by SE (SE-BSIs).

METHODS

We constituted a retrospective cohort in two medical ICUs. SE-BSIs were defined by two or more independent SE-positive blood cultures of the same strain, within 48 hours, without concurrent infection.

RESULTS

We included 59 patients; 58% were men (n = 34), with median age of 67 (interquartile range 60-74) years and a simplified acute physiology score II of 59 (36-74) points, and 56% were immunocompromised (n = 33). Among the 37 (63%) patients requiring norepinephrine initiation or increase at the onset of SE-BSI versus patients not requiring vasopressors (37%; n = 22), concomitant arterial lactate levels reached 2.8 (1.9-5.8) versus 1.5 (1.3-2.2) mmol/l (P <0.01), whereas the mean blood pressure was 49 (42-54) versus 61 (56-65) mm Hg (P = 0.01) and the mortality was 46% (n = 17) vs 14% (n = 3) at day 28 (P = 0.01), respectively. Regarding antibiotics, the susceptibility rates toward linezolid and vancomycin were 71% (n = 41/58) and 100% (n = 54/54), respectively. At the time of SE-BSI, all but one patient had a central venous access device.

CONCLUSION

This work highlights SE-BSIs as a cause of septic shock, mostly in immunocompromised ICU patients, with increasing concerns about resistance to antibiotics and central line management.

A prospective randomized clinical trial to assess antibiotic pocket irrigation on tissue expander breast reconstruction

Bacterial infection is the most common complication following staged post-mastectomy breast reconstruction initiated with a tissue expander (TE). To limit bacterial infection, antibiotic irrigation of the surgical site is commonly performed despite little high-quality data to support this practice. We performed a prospective randomized control trial to compare the impact of saline irrigation alone to a triple antibiotic irrigation regimen (1 g cefazolin, 80 mg gentamicin, and 50,000 units of bacitracin in 500 mL of saline) for breast implant surgery. The microbiome in breasts with cancer (n = 16) was compared to those without (n = 16), as all patients (n = 16) had unilateral cancers but bilateral mastectomies (n = 32). Biologic and prosthetic specimens procured both at the time of mastectomy and during TE removal months later were analyzed for longitudinal comparison. Outcomes included clinical infection, bacterial abundance, and relative microbiome composition. No patient in either group suffered a reconstructive failure or developed an infection. Triple antibiotic irrigation administered at the time of immediate TE reconstruction did not reduce bacterial abundance or impact microbial diversity relative to saline irrigation at the time of planned exchange. Implanted prosthetic material adopted the microbial composition of the surrounding host tissue. In cancer-naïve breasts, relative to saline, antibiotic irrigation increased bacterial abundance on periprosthetic capsules (P = 0.03) and acellular dermal matrices (P = 0.04) and altered the microbiota on both. These data show that, relative to saline only, the use of triple antibiotic irrigation in TE breast reconstruction does impact the bacterial abundance and diversity of certain biomaterials from cancer-naïve breasts. IMPORTANCE The lifetime risk of breast cancer is ~13% in women and is treated with a mastectomy in ~50% of cases. The majority are reconstructed, usually starting with a tissue expander to help restore the volume for a subsequent permanent breast implant or the women's own tissues. The biopsychosocial benefits of breast reconstruction, though, can be tempered by a high complication rate of at least 7% but over 30% in some women. Bacterial infection is the most common complication, and can lead to treatment delays, patient physical and emotional distress and escalating health care cost. To limit this risk, plastic surgeons have tried a variety of strategies to limit bacterial infection including irrigating the pocket created after removing the breast implant with antibiotic solutions, but good-quality data are scarce. Herein, we study the value of antibiotics in pocket irrigation using a robust randomized clinical trial design and molecular microbiology approaches.

Cyclodextrin: A prospective nanocarrier for the delivery of antibacterial agents against bacteria that are resistant to antibiotics

Supramolecular chemistry introduces us to the macrocyclic host cyclodextrin, which has a hydrophobic cavity. The hydrophobic cavity has a higher affinity for hydrophobic guest molecules and forms host-guest complexation with non-covalent interaction. Three significant cyclodextrin kinds are α-cyclodextrin, β-cyclodextrin, and γ-cyclodextrin. The most often utilized is β-cyclodextrin (β-CD). An effective weapon against bacteria that are resistant to antibiotics is cyclodextrin. Several different kinds of cyclodextrin nanocarriers (β-CD, HP-β-CD, Meth-β-CD, cationic CD, sugar-grafted CD) are utilized to enhance the solubility, stability, dissolution, absorption, bioavailability, and permeability of the antibiotics. Cyclodextrin also improves the effectiveness of antibiotics, antimicrobial peptides, metallic nanoparticles, and photodynamic therapy (PDT). Again, cyclodextrin nanocarriers offer slow-release properties for sustained-release formulations where steady-state plasma antibiotic concentration is needed for an extended time. A novel strategy to combat bacterial resistance is a stimulus (pH, ROS)-responsive antibiotics released from cyclodextrin carrier. Once again, cyclodextrin traps autoinducer (AI), a crucial part of bacterial quorum sensing, and reduces virulence factors, including biofilm formation. Cyclodextrin helps to minimize MIC in particular bacterial strains, keep antibiotic concentrations above MIC in the infection site and minimize the possibility of antibiotic and biofilm resistance. Sessile bacteria trapped in biofilms are more resistant to antibiotic therapy than bacteria in a planktonic form. Cyclodextrin also involves delivering antibiotics to biofilm and resistant bacteria to combat bacterial resistance.

Recent Strategies and Future Recommendations for the Fabrication of Antimicrobial, Antibiofilm, and Antibiofouling Biomaterials

Biomaterials and biomedical devices induced life-threatening bacterial infections and other biological adverse effects such as thrombosis and fibrosis have posed a significant threat to global healthcare. Bacterial infections and adverse biological effects are often caused by the formation of microbial biofilms and the adherence of various biomacromolecules, such as platelets, proteins, fibroblasts, and immune cells, to the surfaces of biomaterials and biomedical devices. Due to the programmed interconnected networking of bacteria in microbial biofilms, they are challenging to treat and can withstand several doses of antibiotics. Additionally, antibiotics can kill bacteria but do not prevent the adsorption of biomacromolecules from physiological fluids or implanting sites, which generates a conditioning layer that promotes bacteria's reattachment, development, and eventual biofilm formation. In these viewpoints, we highlighted the magnitude of biomaterials and biomedical device-induced infections, the role of biofilm formation, and biomacromolecule adhesion in human pathogenesis. We then discussed the solutions practiced in healthcare systems for curing biomaterials and biomedical device-induced infections and their limitations. Moreover, this review comprehensively elaborated on the recent advances in designing and fabricating biomaterials and biomedical devices with these three properties: antibacterial (bacterial killing), antibiofilm (biofilm inhibition/prevention), and antibiofouling (biofouling inhibition/prevention) against microbial species and against the adhesion of other biomacromolecules. Besides we also recommended potential directions for further investigations.

Difficult-to-Treat Pathogens: A Review on the Management of Multidrug-Resistant Staphylococcus epidermidis

Multidrug-resistant Staphylococcus epidermidis (MDRSE) is responsible for difficult-to-treat infections in humans and hospital-acquired-infections. This review discusses the epidemiology, microbiology, diagnosis, and treatment of MDRSE infection and identifies knowledge gaps. By using the search term "pan resistant Staphylococcus epidermidis" OR "multi-drug resistant Staphylococcus epidermidis" OR "multidrug-resistant lineages of Staphylococcus epidermidis", a total of 64 records have been identified from various previously published studies. The proportion of methicillin resistance in S. epidermidis has been reported to be as high as 92%. Several studies across the world have aimed to detect the main phylogenetic lineages and antibiotically resistant genes through culture, mass spectrometry, and genomic analysis. Molecular biology tools are now available for the identification of S. epidermidis and its drug resistance mechanisms, especially in blood cultures. However, understanding the distinction between a simple colonization and a bloodstream infection (BSI) caused by S. epidermidis is still a challenge for clinicians. Some important parameters to keep in mind are the number of positive samples, the symptoms and signs of the patient, the comorbidities of the patient, the presence of central venous catheter (CVC) or other medical device, and the resistance phenotype of the organism. The agent of choice for empiric parenteral therapy is vancomycin. Other treatment options, depending on different clinical settings, may include teicoplanin, daptomycin, oxazolidinones, long-acting lipoglycopeptides, and ceftaroline. For patients with S. epidermidis infections associated with the presence of an indwelling device, assessment regarding whether the device warrants removal is an important component of management. This study provides an overview of the MDRSE infection. Further studies are needed to explore and establish the most correct form of management of this infection.

The Effects of Antiperspirant Aluminum Chlorohydrate on the Development of Antibiotic Resistance in Staphylococcus epidermidis

This study investigates the effects of the antiperspirant aluminum chlorohydrate on the development of antibiotic resistance in commensal Staphylococcus epidermidis isolates. The isolates were exposed to aluminum chlorohydrate for 30 days. The bacteria that developed resistance to oxacillin and ciprofloxacin were isolated, and the expression levels of some antibiotic resistance genes were determined using quantitative reverse transcriptase PCR. Before and after exposure, the minimum inhibitory concentration (MIC) values of the bacteria were determined using the microdilution method. A time-dependent increase was observed in the number of bacteria that developed resistance and increased MIC values. Consistent with the ciprofloxacin resistance observed after exposure, an increase in norA, norB/C, gyrA, gyrB, parC, and parE gene expression was observed. In addition to aluminum chlorohydrate exposure, oxacillin resistance was observed in all test bacteria in the group only subcultured in the medium, suggesting that phenotypic resistance cannot be correlated with chemical exposure in light of these data. The increase in mecA gene expression in selected test bacteria that acquired resistance to oxacillin after exposure compared with control groups suggests that the observed resistance may have been related to aluminum chlorohydrate exposure. To our knowledge, this is the first time in the literature that the effects of aluminum chlorohydrate as an antiperspirant on the development of antibiotic resistance in Staphylococcus epidermidis have been reported.

A Review Focusing on Microbial Vertical Transmission during Sow Pregnancy

Microorganisms are closely related to the body's physiological activities and growth and development of the body, and participate in many physiological metabolic activities. Analysis of the structure and source of early colonizing bacteria in the intestinal tract of humans and rodents shows that early colonizing bacteria in the intestinal tract of mammals have solid maternal characteristics, and maternal microbes play an essential role in the formation of progeny intestinal flora. The placental microbiome, maternal microbiome and breast milk microbiome are currently hot topics in the field of life science. This paper discusses the vertical transmission and endogenous sources of the mother-to-piglet microbiome through these three pathways, aiming to provide a new research idea for intervention in the intestinal microbiome in young piglets.

Cryptic Oral Microbiota: What Is Its Role as Obstructive Sleep Apnea-Related Periodontal Pathogens?

Periodontitis has been commonly linked to periodontopathogens categorized in Socransky's microbial complexes; however, there is a lack of knowledge regarding "other microorganisms" or "cryptic microorganisms", which are rarely thought of as significant oral pathogens and have been neither previously categorized nor connected to illnesses in the oral cavity. This study hypothesized that these cryptic microorganisms could contribute to the modulation of oral microbiota present in health or disease (periodontitis and/or obstructive sleep apnea (OSA) patients). For this purpose, the presence and correlation among these cultivable cryptic oral microorganisms were identified, and their possible role in both conditions was determined. Data from oral samples of individuals with or without periodontitis and with or without OSA were obtained from a previous study. Demographic data, clinical oral characteristics, and genera and species of cultivable cryptic oral microorganisms identified by MALDI-TOF were recorded. The data from 75 participants were analyzed to determine the relative frequencies of cultivable cryptic microorganisms' genera and species, and microbial clusters and correlations tests were performed. According to periodontal condition, dental-biofilm-induced gingivitis in reduced periodontium and stage III periodontitis were found to have the highest diversity of cryptic microorganism species. Based on the experimental condition, these findings showed that there are genera related to disease conditions and others related to healthy conditions, with species that could be related to different chronic diseases being highlighted as periodontitis and OSA comorbidities. The cryptic microorganisms within the oral microbiota of patients with periodontitis and OSA are present as potential pathogens, promoting the development of dysbiotic microbiota and the occurrence of chronic diseases, which have been previously proposed to be common risk factors for periodontitis and OSA. Understanding the function of possible pathogens in the oral microbiota will require more research.

Sonicate Fluid Cellularity Predicted by Transcriptomic Deconvolution Differentiates Infectious from Non-Infectious Arthroplasty Failure

BACKGROUND

Although cellularity is traditionally assessed morphologically, deep sequencing approaches being used for microorganism detection may be able to provide information about cellularity. We hypothesized that cellularity predicted using CIBERSORTx (Stanford University), a transcriptomic-based cellular deconvolution tool, would differentiate between infectious and non-infectious arthroplasty failure.

METHODS

CIBERSORTx-derived cellularity profiles of 93 sonicate fluid samples, including 53 from subjects who underwent failed arthroplasties due to periprosthetic joint infection (PJI) (abbreviated for the purpose of this study as PJIF) and 40 from subjects who had undergone non-infectious arthroplasty failure (abbreviated NIAF) that had been subjected to bulk RNA sequencing were evaluated.

RESULTS

Samples from PJIF and NIAF subjects were differentially clustered by principal component analysis based on the cellularity profile. Twelve of the 22 individual predicted cellular fractions were differentially expressed in the PJIF cases compared with the NIAF cases, including increased predicted neutrophils (mean and standard error, 9.73% ± 1.06% and 0.81% ± 0.60%), activated mast cells (17.12% ± 1.51% and 4.11% ± 0.44%), and eosinophils (1.96% ± 0.37% and 0.42% ± 0.21%), and decreased predicted M0 macrophages (21.33% ± 1.51% and 39.75% ± 2.45%), M2 macrophages (3.56% ± 0.52% and 8.70% ± 1.08%), and regulatory T cells (1.57% ± 0.23% and 3.20% ± 0.34%). The predicted total granulocyte fraction was elevated in the PJIF cases (32.97% ± 2.13% and 11.76% ± 1.61%), and the samples from the NIAF cases had elevated predicted total macrophage and monocyte (34.71% ± 1.71% and 55.34% ± 2.37%) and total B cell fractions (5.89% ± 0.30% and 8.62% ± 0.86%). Receiver operating characteristic curve analysis identified predicted total granulocytes, neutrophils, and activated mast cells as highly able to differentiate between the PJIF cases and the NIAF cases. Within the PJIF cases, the total granulocyte, total macrophage and monocyte, M0 macrophage, and M2 macrophage fractions were differentially expressed in Staphylococcus aureus compared with Staphylococcus epidermidis -associated samples. Within the NIAF cases, the predicted total B cell, naïve B cell, plasma cell, and M2 macrophage fractions were differentially expressed among different causes of failure.

CONCLUSIONS

CIBERSORTx can predict the cellularity of sonicate fluid using transcriptomic data, allowing for the evaluation of the underlying immune response during the PJIF and NIAF cases, without a need to phenotypically assess cell composition.

Asian Ancistrocladus Lianas as Creative Producers of Naphthylisoquinoline Alkaloids

This book describes a unique class of secondary metabolites, the mono- and dimeric naphthylisoquinoline alkaloids. They occur in lianas of the paleotropical Ancistrocladaceae and Dioncophyllaceae families, exclusively. Their unprecedented structures include stereogenic centers and rotationally hindered, and thus likewise stereogenic, axes. Extended recent investigations on six Ancistrocladus species from Asia, as reported in this review, shed light on their fascinating phytochemical productivity, with over 100 such intriguing natural products. This high chemodiversity arises from a likewise unique biosynthesis from acetate-malonate units, following a novel polyketidic pathway to plant-derived isoquinoline alkaloids. Some of the compounds show most promising antiparasitic activities. Likewise presented are strategies for the regio- and stereoselective total synthesis of the alkaloids, including the directed construction of the chiral axis.

Identification and design of a multi-epitope subunit vaccine against the opportunistic pathogen Staphylococcus epidermidis: An immunoinformatics approach

Staphylococcus epidermidis is one of the major causes of nosocomial infections around the globe that leads to a high rate of mortality and morbidity in both immunocompromised patients and preterm infants. Despite the alarming increase in multi-drug resistance, no promising vaccines are readily available against this pathogen. Thus, the present study is focused on designing a multi-epitope subunit vaccine using five antigenic proteins of S. epidermidis through an immunoinformatics approach. The final vaccine comprised B-cell, HTL, and CTL binding epitopes followed by Lipoprotein LprA adjuvant added at N-terminal to augment the immunogenicity. Physicochemical assessment of the vaccine reveals the antigenic and non-allergic nature. The vaccine structure was designed, refined, validated, and disulfide engineered to obtain the best model. Molecular docking and dynamics simulation of the proposed vaccine with toll-like receptors (TLR-2 and TLR-4) showed strong and stable interactions. MM-PBSA analysis was implemented as an efficient tool to determine the intermolecular binding free energies of the system. The vaccine was subjected to immune simulation to predict its immunogenic profile. In silico cloning suggested that the proposed vaccine can be expressed efficiently in E.coli. Furthermore, in vivo animal experiment is needed to determine the effectiveness of the in silico designed vaccine.Communicated by Ramaswamy H. Sarma.

The staphylococcal biofilm protein Aap mediates cell-cell adhesion through mechanically distinct homophilic and lectin interactions

The accumulation phase of staphylococcal biofilms relies on both the production of an extracellular polysaccharide matrix and the expression of bacterial surface proteins. A prototypical example of such adhesive proteins is the long multidomain protein Aap (accumulation-associated protein) from Staphylococcus epidermidis, which mediates zinc-dependent homophilic interactions between Aap B-repeat regions through molecular forces that have not been investigated yet. Here, we unravel the remarkable mechanical strength of single Aap-Aap homophilic bonds between living bacteria and we demonstrate that intercellular adhesion also involves sugar binding through the lectin domain of the Aap A region. We find that the mechanical force needed to unfold individual β-sheet-rich G5-E domains from the Aap B-repeat regions is very high, ranging from 300 up to 1,000 pN at high loading rates, indicating these are extremely stable. This high mechanostability provides a means to the cells to form highly adhesive and cohesive biofilms capable of sustaining high physiological shear stress. Importantly, we identify a previously undescribed role of Aap in bacterial-bacterial adhesion, that is, heterophilic sugar binding by a specific lectin domain located in the N-terminal A region, which might be important to establish initial contacts between cells before strong homophilic bonds come into play. This study emphasizes the remarkable mechanical and binding properties of Aap as well as its wide diversity of adhesive functions.

Co-Management Reduces Mortality in Post-Sternotomy Mediastinitis

Background: Post-sternotomy mediastinitis (PSM) is one of the most feared complications of cardiac surgery. The impact of a multidisciplinary management approach on this pathology is yet unknown. Patients and Methods: A multidisciplinary approach based on a co-management model (CMM) of care was initiated in January 2018 because of the incorporation of a hospitalist unit on a cardiac surgery department. An observational retrospective cohort study was designed to evaluate the impact of the CMM of care compared to the standard model (SM) of care in patients diagnosed with PSM. Our primary and secondary outcomes were survival time and treatment failure rate (two or more surgical procedures needed to solve PSM or PSM-related death), respectively. Data related to patient death date were collected from the Spanish National Death Index. A multivariable Cox regression model was created using those variables believed to be clinically relevant. Results: Ninety-one patients developed PSM from January 2010 to June 2020. Regarding the pre-operative clinical status, surgical procedure, and PSM severity, both groups had similar baseline characteristics. Patients were followed for a mean of 27.54 ± 30.5 months. A total of 60.3% of the SM group and 11.1% of the CMM group (p < 0.001) died. Treatment failure occurred in 53 patients (72.6%) in the SM group versus 7 (38.6%) in the CMM group (p = 0.007). The CMM independently reduced overall mortality (hazard ratio [HR], 0.11; 95% confidence interval [CI]. 0.01-0.83) and treatment failure rate (HR, 0.01; 95% CI, 0.001-0.183). Gram-positive bacterial infection (HR, 3.73; 95% CI, .6-8.3), and complete osteosynthesis material removal (HR, 0.47; 95% CI, 0.24-0.91) also influenced mortality in our model. Conclusions: A co-management care model reduced overall mortality in patients diagnosed with post-sternotomy mediastinitis.

Property of mud and its application in cosmetic and medical fields: a review

Mud is a semi-colloidal substance formed by the mixture of inorganic, organic and water under the influence of various physical and chemical factors through geological and biological processes. The chemical composition of mud is complex, rich in Ca²⁺, Zn²⁺, Mg²⁺, Na⁺ and other mineral elements, also contains organic matter such as humic acid, fulvic acid and acetic acid. In cosmetic field, mud can improve the activity of glutathione enzyme and superoxide dismutase in skin, which helps the skin anti-aging. Besides, it also can improve the skin microbial community, due to its distinctively physical properties, mineral ions, microorganisms, etc. In medical field, mud can treat osteoarthritis, especially knee osteoarthritis which has been studied extensively, and it can also increase the chemotaxis of macrophages. On the one hand, the use of clay (a kind of refined mud) can protect the gastrointestinal tract and treat some gastrointestinal diseases. On the other hand, clay is often used as carriers or composites in drug delivery, especially in skin drug delivery, showing very positive results. The purpose of this review is to present an overview of current knowledge about the application of mud in cosmetic and medical fields and to provide ideas for further research in mud.

A novel approach for combining the metagenome, metaresistome, metareplicome and causal inference to determine the microbes and their antibiotic resistance gene repertoire that contribute to dysbiosis

The use of whole metagenomic data to infer the relative abundance of all its microbes is well established. The same data can be used to determine the replication rate of all eubacterial taxa with circular chromosomes. Despite their availability, the replication rate profiles (metareplicome) have not been fully exploited in microbiome analyses. Another relatively new approach is the application of causal inferencing to analyse microbiome data that goes beyond correlational studies. A novel scalable pipeline called MeRRCI (Metagenome, metaResistome, and metaReplicome for Causal Inferencing) was developed. MeRRCI combines efficient computation of the metagenome (bacterial relative abundance), metaresistome (antimicrobial gene abundance) and metareplicome (replication rates), and integrates environmental variables (metadata) for causality analysis using Bayesian networks. MeRRCI was applied to an infant gut microbiome data set to investigate the microbial community's response to antibiotics. Our analysis suggests that the current treatment stratagem contributes to preterm infant gut dysbiosis, allowing a proliferation of pathobionts. The study highlights the specific antibacterial resistance genes that may contribute to exponential cell division in the presence of antibiotics for various pathogens, namely Klebsiella pneumoniae, Citrobacter freundii, Staphylococcus epidermidis, Veilonella parvula and Clostridium perfringens. These organisms often contribute to the harmful long-term sequelae seen in these young infants.

The issue beyond resistance: Methicillin-resistant Staphylococcus epidermidis biofilm formation is induced by subinhibitory concentrations of cloxacillin, cefazolin, and clindamycin

Staphylococcus epidermis is one of the most frequent causes of device-associated infections due to biofilm formation. Current reports noted that subinhibitory concentrations of antibiotics induce biofilm production in some bacteria. Accordingly, we evaluated the effect of exposure of different subinhibitory concentrations of cloxacillin, cefazolin, clindamycin, and vancomycin on the biofilm formation of methicillin-resistant S. epidermidis (MRSE). Antimicrobial susceptibility testing and minimum inhibitory/bactericidal concentration of antimicrobial agents were determined. MRSE isolates were selected, and their biofilm formation ability was evaluated. The effect of subinhibitory concentrations of cloxacillin, cefazolin, clindamycin, and vancomycin, antibiotics selected among common choices in the clinic, on MRSE biofilm formation was determined by the microtitre method. Besides, the effect of subinhibitory concentrations of cloxacillin, cefazolin, clindamycin, and vancomycin on the expression of the biofilm-associated genes icaA and atlE was evaluated by Reverse-transcription quantitative real-time polymerase chain reaction (RT-qPCR). Antimicrobial susceptibility patterns of MRSE strains showed a high level of resistance as follows: 80%, 53.3%, 33.3%, 33.3%, and 26.6%, for erythromycin, trimethoprim-sulfamethoxazole, tetracycline, clindamycin, and gentamicin, respectively. Besides, 73.3% of S. epidermidis strains were Multidrug-resistant (MDR). Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values were in the range of 0.5 to512 μg/mL and 1 to1024 μg/mL for cloxacillin, 0.125 to256 μg/mL and 1 to512 μg/mL for cefazolin, 0.125 to64 μg/mL and 4 to>1024 μg/mL for clindamycin, and 2 to32 μg/mL and 4 to32 μg/mL for vancomycin, respectively. The findings showed that subinhibitory concentrations of cloxacillin, cefazolin, and clindamycin induce biofilm production in MRSE strains. In particular, the OD values of strains were in the range of 0.09-0.95, 0.05-0.86, and 0.06-1 toward cloxacillin, cefazolin, and clindamycin, respectively. On the other hand, exposure to subinhibitory vancomycin concentrations did not increase the biofilm formation in MRSE strains. The findings also demonstrated that sub-MIC of antibiotics up-regulated biofilm-associated genes. In particular, atlE and icaA were up-regulated 0.062 to 1.16 and 0.078 to 1.48 folds, respectively, for cloxacillin, 0.11 to 0.8, and 0.1 to 1.3 folds for cefazolin, 0.18 to 0.98, and 0.19 to 1.4 folds, respectively, for clindamycin. In contrast, the results showed that sub-MIC of vancomycin did not increase the biofilm-associated genes. These findings overall show that exposure to sub-MIC of traditional antibiotics can cause biofilm induction in MRSE, thereby increasing the survival and persistence on various surfaces that worsen the condition of comorbid infections.

Microbiological Aspects Concerning the Etiology of Acute Odontogenic Inflammatory Diseases in the Soft Tissues of the Head and Neck Region

Odontogenic purulent inflammatory diseases (OPID) make up about 20% of cases in the structure of general surgical pathology and are among the frequent diseases of the maxillofacial region (MFR) with a high (10-40%) mortality rate. Insufficient information about the source state of acute odontogenic inflammation of the peri-mandibular soft tissues significantly reduces the effectiveness of diagnostic measures of OPID in MFR, as evidenced by almost 50% of the diagnostic error rate. Statistically, OPID in soft-tissue of MFR most often occur due to dissemination of pathogens of the necrotized pulp, periodontal pockets in periodontitis or pericoronitis during the difficult eruption of retained teeth. Previously, the quantitative dominance (about 70%) of Staphylococcus spp. among the microorganisms isolated from the odontogenic foci of inflammation was determined. However, in recent years, with the expansion of microbiological diagnostic capabilities, the presence of non-fermenting Gram-negative bacteria and anaerobes with a significant proportional proportion of the total microbiota of OPID in soft tissue of MFR has been increasingly indicated. Recently, there has been a rapid acquisition of resistance of pathogens of odontogenic purulent inflammatory diseases of the maxillofacial region to various groups of antibiotics, which leads to ineffectiveness of their treatment and prompts the revision of existing protocols and treatment regimens in surgical dentistry

Lactobacillus rhamnosus and Staphylococcus epidermidis in gut microbiota: in vitro antimicrobial resistance

The gastrointestinal tract is one of the most complex microbiological niches containing beneficial and non-pathogenic bacterial strains of which some may evolve into virulent under specific conditions. Lactobacillus rhamnosus GG is of the most known beneficial species with an ability to protect the intestine as opposed to Staphylococcus epidermidis 444 which causes serious health risks due to its high antimicrobial resistance. This study investigates first the survival and coexistence ability of L. rhamnosus GG, and S. epidermidis 444 at different pH levels. Subsequently, lysozyme's antimicrobial and antibiofilm effect on these two strains was elucidated before adding different concentrations of oxytetracycline hydrochloride antibiotic. Results showed that 50% inhibition of L. rhamnosus GG, S. epidermidis 444, and a co-culture of these planktonic strains were obtained respectively at a lysozyme concentration of 30, 18, and 26 mg/mL after the addition of ethylenediamine tetra-acetic acid (EDTA). At a pH of 7.5, mixing lysozyme (at IC₅₀) and EDTA with oxytetracycline hydrochloride (700 μg/mL) showed an additional bactericidal effect as compared to its known bacteriostatic effect. Similarly, the addition of lysozyme to the antibiotic further increased the biofilm eradication of S. epidermidis 444 and L. rhamnosus GG where a maximal eradication of 70% was reached. Therefore, the potential development of new drugs based on adding a lysozyme-EDTA mixture to different types of antibiotics may be highly promising.

Skin-to-blood pH shift triggers metabolome and proteome global remodelling in Staphylococcus epidermidis

Staphylococcus epidermidis is one of the most common bacteria of the human skin microbiota. Despite its role as a commensal, S. epidermidis has emerged as an opportunistic pathogen, associated with 80% of medical devices related infections. Moreover, these bacteria are extremely difficult to treat due to their ability to form biofilms and accumulate resistance to almost all classes of antimicrobials. Thus new preventive and therapeutic strategies are urgently needed. However, the molecular mechanisms associated with S. epidermidis colonisation and disease are still poorly understood. A deeper understanding of the metabolic and cellular processes associated with response to environmental factors characteristic of SE ecological niches in health and disease might provide new clues on colonisation and disease processes. Here we studied the impact of pH conditions, mimicking the skin pH (5.5) and blood pH (7.4), in a S. epidermidis commensal strain by means of next-generation proteomics and 1H NMR-based metabolomics. Moreover, we evaluated the metabolic changes occurring during a sudden pH change, simulating the skin barrier break produced by a catheter. We found that exposure of S. epidermidis to skin pH induced oxidative phosphorylation and biosynthesis of peptidoglycan, lipoteichoic acids and betaine. In contrast, at blood pH, the bacterial assimilation of monosaccharides and its oxidation by glycolysis and fermentation was promoted. Additionally, several proteins related to virulence and immune evasion, namely extracellular proteases and membrane iron transporters were more abundant at blood pH. In the situation of an abrupt skin-to-blood pH shift we observed the decrease in the osmolyte betaine and changes in the levels of several metabolites and proteins involved in cellular redoxl homeostasis. Our results suggest that at the skin pH S. epidermidis cells are metabolically more active and adhesion is promoted, while at blood pH, metabolism is tuned down and cells have a more virulent profile. pH increase during commensal-to-pathogen conversion appears to be a critical environmental signal to the remodelling of the S. epidermidis metabolism toward a more pathogenic state. Targeting S. epidermidis proteins induced by pH 7.4 and promoting the acidification of the medical device surface or surrounding environment might be new strategies to treat and prevent S. epidermidis infections.

Preoperative contrast-enhanced ultrasound (CEUS) of long bone nonunions reliably predicts microbiology of tissue culture samples but not of implant-sonication

INTRODUCTION

Bacterial infection in the context of fracture repair remains a severe complication in trauma surgery and may result in long bone nonunion. Since treatment options for aseptic and infected nonunions vary greatly, diagnostic methods should ideally differentiate between these two entities as accurately as possible. Recently, contrast-enhanced ultrasound (CEUS) has been introduced as a preoperative imaging technique to evaluate hypervascularity at the fracture site as sign of bacterial infection.

HYPOTHESIS

Preoperative CEUS predicts results of microbiological evaluation obtained either by culture of tissue samples or by analyzing the sonication fluid following removal and sonication of the implant.

PATIENTS AND METHODS

Over the course of 6 months, 26 patients with long bone nonunions were included in this study. Patients' clinical data were evaluated. Tissue samples were collected intraoperatively and examined by standard microbiological techniques. The sonication method was applied to removed implants. Additionally, 1-3 days before surgery, CEUS was performed to determine hypervascularity at the nonunion site as a possible parameter for infection.

RESULTS

Culture of tissue samples indicated infection in 50% of cases and implant sonication in 57.7% of cases. However, there was merely a fair agreement (κ=0.231) between these two diagnostic methods. CEUS predicted results of tissue culture reliably (sensitivity 92.3% and specificity 100%), whereas implant sonication showed no significant correlations with results from CEUS. Hypertrophic and atrophic nonunions were evaluated separately to determine possible differences in vascularity. We found that contrast peak enhancement of CEUS was similar in atrophic and hypertrophic nonunions with positive culture of tissue samples. Both differed significantly from culture negative cases (p=0.0016 and 0.0062). Results of implant-sonication positive or negative cases in atrophic and hypertrophic nonunions, however, were less clear and could be misleading.

DISCUSSION

We were able to confirm CEUS as a valuable preoperative diagnostic tool that reliably predicts microbiology of tissue culture samples, but not of implant sonication.

LEVEL OF EVIDENCE

I; diagnostic study.

Controlling skin microbiome as a new bacteriotherapy for inflammatory skin diseases

The skin serves as the interface between the human body and the environment and interacts with the microbial community. The skin microbiota consists of microorganisms, such as bacteria, fungi, mites, and viruses, and they fluctuate depending on the microenvironment defined by anatomical location and physiological function. The balance of interactions between the host and microbiota plays a pivotal role in the orchestration of skin homeostasis; however, the disturbance of the balance due to an alteration in the microbial communities, namely, dysbiosis, leads to various skin disorders. Recent developments in sequencing technology have provided new insights into the structure and function of skin microbial communities. Based on high-throughput sequencing analysis, a growing body of evidence indicates that a new treatment using live bacteria, termed bacteriotherapy, is a feasible therapeutic option for cutaneous diseases caused by dysbiosis. In particular, the administration of specific bacterial strains has been investigated as an exclusionary treatment strategy against pathogens associated with chronic skin disorders, whereas the safety, efficacy, and sustainability of this therapeutic approach using isolated live bacteria need to be further explored. In this review, we summarize our current understanding of the skin microbiota, as well as therapeutic strategies using characterized strains of live bacteria for skin inflammatory diseases. The ecosystem formed by interactions between the host and skin microbial consortium is still largely unexplored; however, advances in our understanding of the function of the skin microbiota at the strain level will lead to the development of new therapeutic methods.

Chemistry and Bioactivity of Microsorum scolopendria (Polypodiaceae): Antioxidant Effects on an Epithelial Damage Model

Microsorum scolopendia (MS), which grows on the Chilean island of Rapa Nui, is a medicinal fern used to treat several diseases. Despite being widely used, this fern has not been deeply investigated. The aim of this study was to perform a characterization of the polyphenolic and flavonoid identity, radical scavenging, antimicrobial, and anti-inflammatory properties of MS rhizome and leaf extracts (RAE and HAE). The compound identity was analyzed through the reversed-phase high-performance liquid chromatography (RP-HPLC) method coupled with mass spectrometry. The radical scavenging and anti-inflammatory activities were evaluated for DPPH, ORAC, ROS formation, and COX inhibition activity assay. The antimicrobial properties were evaluated using an infection model on Human Dermal Fibroblast adult (HDFa) cell lines incubated with Staphylococcus aureus and Staphylococcus epidermidis. The most abundant compounds were phenolic acids between 46% to 57% in rhizome and leaf extracts, respectively; followed by flavonoids such as protocatechic acid 4-O-glucoside, cirsimaritin, and isoxanthohumol, among others. MS extract inhibited and disaggregated the biofilm bacterial formed and showed an anti-inflammatory selective property against COX-2 enzyme. RAE generated a 64% reduction of ROS formation in the presence of S. aureus and 87.35% less ROS in the presence of S. epidermidis on HDFa cells. MS has great therapeutic potential and possesses several biological properties that should be evaluated.

A Bombyx mori Infection Model for Screening Antibiotics against Staphylococcus epidermidis

The increasing number of microorganisms that are resistant to antibiotics is prompting the development of new antimicrobial compounds and strategies to fight bacterial infections. The use of insects to screen and test new drugs is increasingly considered a promising tool to accelerate the discovery phase and limit the use of mammalians. In this study, we used for the first time the silkworm, Bombyx mori, as an in vivo infection model to test the efficacy of three glycopeptide antibiotics (GPAs), against the nosocomial pathogen Staphylococcus epidermidis. To reproduce the human physiological temperature, the bacterial infection was performed at 37 °C and it was monitored over time by evaluating the survival rate of the larvae, as well the response of immunological markers (i.e., activity of hemocytes, activation of the prophenoloxidase system, and lysozyme activity). All the three GPAs tested (vancomycin, teicoplanin, and dalbavancin) were effective in curing infected larvae, significantly reducing their mortality and blocking the activation of the immune system. These results corroborate the use of this silkworm infection model for the in vivo studies of antimicrobial molecules active against staphylococci.

Non-doped and transition metal-doped CuO nano-powders: structure-physical properties and anti-adhesion activity relationship

Bacterial contamination and biofilm formation generate severe problems in many fields. Among these biofilm-forming bacteria, Staphylococcus epidermidis (S. epidermidis) has emerged as a major cause of nosocomial infection (NI). However, with the dramatic rise in resistance toward conventional antibiotics, there is a pressing need for developing effective anti-biofilms. So, fabrication of copper oxide nanoparticles (NPs) is one of the new strategies to combat biofilms. Notably, doped CuO NPs in anti-biofilm therapy have become a hot spot of attention in recent years due to their physicochemical properties. In this context, the present work deals with the investigation of undoped and transition metal (TM)-doped CuO NPs (TM = Zn, Ni, Mn, Fe and Co), synthesized via the co-precipitation method. The synthesized CuO NPs are characterized using X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, field-emission scanning electron microscopy (FE-SEM), energy dispersive spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS). Results consistently revealed the successful formation of CuO NPs using the co-precipitation method and confirmed that TM ions are successfully inserted into CuO crystal lattice. We found that doping changes the morphology of the CuO NPs and increases their crystallite size. The XPS results show a non-uniform distribution of the doping concentration, with a depletion or an enrichment of the NP surface depending on the element considered. Furthermore, the anti-adhesive potential of CuO NPs against S. epidermidis S61 biofilm formation is evaluated in this study by crystal violet and fluorescence microscopy assays. All synthesized NPs exhibit considerable anti-adhesive activity against S. epidermidis S61 biofilm. Interestingly, compared to undoped CuO, Fe and Ni-doped oxides show an improved activity when used at high concentrations, whereas Mn-doped CuO is the most efficient at low concentrations. This makes TM-doped CuO a promising candidate to be used in biomedical applications.

Effect of New 2-Thioxoimidazolidin-4-one Compounds against Staphylococcus aureus Clinical Strains and Immunological Markers’ Combinations

Although the structure-activity relationship indicates that the 4-thioxoimidazolidin ring is essential for antibacterial activities and pharmaceutical applications, there were no enough studies on the derivatives of this compound. Evaluating the new hydantoin compounds C5 (3-((2-bromobenzylidene) amino)-2- thioxoimidazolidin-4-one) and C6 (3-((4- methoxybenzylidene) amino)-2-thioxoimidazolidin-4-one) that were prepared against clinical Staphylococcus aureus isolates for antibacterial, antibiofilm, and antihemagglutination activities is the aim of this study. Therefore, the potential clinical resistance of the strains was evaluated by their ability to form biofilms, antibiotic resistance, and agglutinate erythrocytes macroscopically and microscopically; besides, the bacterial biofilm was screened for any association with the patient's serum immunoglobulin levels and complements. Despite the effective concentration for C5 and C6 compounds, which is ≤ 31.25 μg/ml, the reduction rate is not concentration-dependent; it depends on the molecular docking of the hydantoin compounds. Hence, the effect of the minimal inhibitory concentrations (MICs) is variable. In this study, the results for the compounds (with the concentration of 31.25–62.5 μg/mL for C5 and 62.5–125 μg/mL for C6) significantly manifest the antibacteria, antibiofilm, and antihemagglutination effects against the virulent strains of S. aureus due to the high percentage of biofilm inhibition that was caused by the new hydantoin compounds. Besides, time-kill kinetics studies showed that these compounds pose bactericidal action. Overall, this study revealed that the new hydantoin derivatives have an interesting potential as new antibacterial drugs through the inhibition of bacterial adhesion. The infections of these isolates activate the complement system through the lectin pathway. Nevertheless, these compounds can be improved in order to be used at even lower concentrations.

Skeletal infections: microbial pathogenesis, immunity and clinical management

Osteomyelitis remains one of the greatest risks in orthopaedic surgery. Although many organisms are linked to skeletal infections, Staphylococcus aureus remains the most prevalent and devastating causative pathogen. Important discoveries have uncovered novel mechanisms of S. aureus pathogenesis and persistence within bone tissue, including implant-associated biofilms, abscesses and invasion of the osteocyte lacuno-canalicular network. However, little clinical progress has been made in the prevention and eradication of skeletal infection as treatment algorithms and outcomes have only incrementally changed over the past half century. In this Review, we discuss the mechanisms of persistence and immune evasion in S. aureus infection of the skeletal system as well as features of other osteomyelitis-causing pathogens in implant-associated and native bone infections. We also describe how the host fails to eradicate bacterial bone infections, and how this new information may lead to the development of novel interventions. Finally, we discuss the clinical management of skeletal infection, including osteomyelitis classification and strategies to treat skeletal infections with emerging technologies that could translate to the clinic in the future.

Highly Synergistic Effects of Melittin With Vancomycin and Rifampin Against Vancomycin and Rifampin Resistant Staphylococcus epidermidis

Methicillin-resistant Staphylococcus epidermidis (MRSE) strains are increasingly emerging as serious pathogens because they can be resistant to many antibiotics called multidrug resistance (MDR) that limit the therapeutic options. In the case of vancomycin- and rifampin-resistant MDR-MRSE, the physicians are not allowed to increase the doses of antibiotics because of severe toxicity. Accordingly, we investigated the synergistic activity of melittin antimicrobial peptide with vancomycin and rifampin against vancomycin-resistant, and rifampin-resistant MDR-MRSE isolates. Minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), fractional inhibitory concentration index (FICi), and fractional bactericidal concentration index (FBCi) of antimicrobial agents against isolates were determined. Coagulate activities and serum and salt stability as well as melittin cytotoxicity on the human embryonic kidney (HEK) 293 cells and human red blood cells (RBCs) at their synergistic concentrations. MIC and MBC values for melittin were in the range of 0.312–2.5 and 0.312–5, respectively. Results also showed that the interaction of melittin with drugs was highly synergistic in which the geometric means of FICi and FBCi were < 0.5. Induced synergism led to a decrease in melittin, rifampin, and vancomycin concentrations by 8–1,020, 2–16, and 4–16-folds, respectively. This phenomenon caused a reduction in melittin toxicity by which the synergistic concentration of melittin needed to kill bacteria did not show cytotoxicity and hemolytic activity. Besides, no coagulation activity was found for the synergistic and alone concentrations of melittin in both Prothrombin Time (PT) and Partial Thromboplastin Time (PTT). Interestingly, the antibacterial activity of melittin in Mueller Hinton Broth (MHB) containing human serum did no significant differences between MIC and MBC values of melittin in MHB and MHB containing 10% human serum. The present findings showed that the therapeutic index of melittin was improved by 32.08- and 12.82-folds when combined with vancomycin and rifampin, respectively. Taken together, the obtained data show that melittin alone was effective against MDR-MRSE isolates and this antimicrobial peptide showed highly synergistic effects with vancomycin and rifampin without causing toxicity. Therefore, the combination of melittin and traditional antibiotics could be a promising strategy for the treatment of infections caused by MDR-MRSE.

Lack of Direct Correlation between Biofilm Formation and Antimicrobial Resistance in Clinical Staphylococcus epidermidis Isolates from an Italian Hospital

Staphylococcus epidermidis is an opportunistic pathogen and a frequent cause of nosocomial infections. In this work, we show that, among 51 S. epidermidis isolates from an Italian hospital, only a minority displayed biofilm formation, regardless of their isolation source (peripheral blood, catheter, or skin wounds); however, among the biofilm-producing isolates, those from catheters were the most efficient in biofilm formation. Interestingly, most isolates including strong biofilm producers displayed production levels of PIA (polysaccharide intercellular adhesin), the main S. epidermidis extracellular polysaccharide, similar to reference S. epidermidis strains classified as non-biofilm formers, and much lower than those classified as intermediate or high biofilm formers, possibly suggesting that high levels of PIA production do not confer a particular advantage for clinical isolates. Finally, while for the reference S. epidermidis strains the biofilm production clearly correlated with the decreased sensitivity to antibiotics, in particular, protein synthesis inhibitors, in our clinical isolates, such positive correlation was limited to tetracycline. In contrast, we observed an inverse correlation between biofilm formation and the minimal inhibitory concentrations for levofloxacin and teicoplanin. In addition, in growth conditions favoring PIA production, the biofilm-forming isolates showed increased sensitivity to daptomycin, clindamycin, and erythromycin, with increased tolerance to the trimethoprim/sulfamethoxazole association. The lack of direct correlation between the biofilm production and increased tolerance to antibiotics in S. epidermidis isolates from a clinical setting would suggest, at least for some antimicrobials, the possible existence of a trade-off between the production of biofilm determinants and antibiotic resistance.

Linker-Improved Chimeric Endolysin Selectively Kills Staphylococcus aureus In Vitro, on Reconstituted Human Epidermis, and in a Murine Model of Skin Infection

Staphylococcus aureus causes a broad spectrum of diseases in humans and animals. It is frequently associated with inflammatory skin disorders such as atopic dermatitis, where it aggravates symptoms. Treatment of S. aureus-associated skin infections with antibiotics is discouraged due to their broad-range deleterious effect on healthy skin microbiota and their ability to promote the development of resistance. Thus, novel S. aureus-specific antibacterial agents are desirable. We constructed two chimeric cell wall-lytic enzymes, Staphefekt SA.100 and XZ.700, which are composed of functional domains from the bacteriophage endolysin Ply2638 and the bacteriocin lysostaphin. Both enzymes specifically killed S. aureus and were inactive against commensal skin bacteria such as Staphylococcus epidermidis, with XZ.700 proving more active than SA.100 in multiple in vitro activity assays. When surface-attached mixed staphylococcal cultures were exposed to XZ.700 in a simplified microbiome model, the enzyme selectively removed S. aureus and retained S. epidermidis. Furthermore, XZ.700 did not induce resistance in S. aureus during repeated rounds of exposure to sublethal concentrations. Finally, we demonstrated that XZ.700 formulated as a cream is effective at killing S. aureus on reconstituted human epidermis and that an XZ.700-containing gel significantly reduces bacterial numbers compared to an untreated control in a mouse model of S. aureus-induced skin infection.

The Staphylococcus epidermidis Transcriptional Profile During Carriage

The virulence factors of the opportunistic human pathogen Staphylococcus epidermidis have been a main subject of research. In contrast, limited information is available on the mechanisms that allow the bacterium to accommodate to the conditions during carriage, a prerequisite for pathogenicity. Here, we tested the hypothesis that the adaptation of S. epidermidis at different anatomical sites is reflected by differential gene regulation. We used qPCR to profile S. epidermidis gene expression in vivo in nose and skin swabs of 11 healthy individuals. Despite some heterogeneity between individuals, significant site-specific differences were detected. For example, expression of the S. epidermidis regulator sarA was found similarly in the nose and on the skin of all individuals. Also, genes encoding colonization and immune evasion factors (sdrG, capC, and dltA), as well as the sphingomyelinase encoding gene sph, were expressed at both anatomical sites. In contrast, expression of the global regulator agr was almost inactive in the nose but readily present on the skin. A similar site-specific expression profile was also identified for the putative chitinase-encoding SE0760. In contrast, expression of the autolysine-encoding gene sceD and the wall teichoic acid (WTA) biosynthesis gene tagB were more pronounced in the nose as compared to the skin. In summary, our analysis identifies site-specific gene expression patterns of S. epidermidis during colonization. In addition, the observed expression signature was significantly different from growth in vitro. Interestingly, the strong transcription of sphingomyelinase together with the low expression of genes encoding the tricarboxylic acid cycle (TCA) suggests very good nutrient supply in both anatomical niches, even on the skin where one might have suspected a rather lower nutrient supply compared to the nose.

Sweat contamination induced surgical site infections after spine surgery: Three case reports and literature review

Introduction and importance

Surgical site infection (SSI) is one of the most intractable complications following spine surgery during the early postoperative stage. Elderly (age > 70 years), body mass index > 30, smoking, diabetes mellitus, coronary artery disease, chronic obstructive pulmonary disease, anemia, low serum albumin, operation time > 3 h, and perioperative blood loss > 500 mL are the common risk factors of SSI after spine surgery. However, there are few published reports about sweat contamination induced surgical site infections with Staphylococcus epidermidis up to date. Staphylococcus epidermidis is a permanent member of the normal human microbiota and has emerged as an important opportunistic pathogen in SSI. We aim to detect the influence of sweat infiltration on SSI with Staphylococcus epidermidis and effective management.

Case presentation

A 73-year-old male, a 54-year-old male and a 73-year-old female were admitted to our hospital. All of them underwent posterior compression and fusion surgery with internal fixation and got surgical site infection after primary surgery. Two of them suffered moderate surgical site infection while the third patient with comorbidities suffered severe surgical site infection. Antibiotic therapy and debridement with internal fixation retained were utilized during which microbiological culture were taken. The moderate infection patients got fully recovered after debridement and primary suture while the serious one had recurrence after the first debridement, and then the second operation was performed. SSI, however, relapsed after three days. Vacuum-assisted closure (VAC) system was placed in the third debridement. The severe patient got well recovered and discharged after displacement of VAC system.

Clinical discussion

This report serves to explore a normal but overlooked factor for SSI. SSI is one of the most intractable complications after spine surgery and the report introduce some uncomplicated but effective methods to moderate and severe SSI.

Conclusion

Sweat-contaminated is an inducement of SSI with Staphylococcus epidermidis that should attract surgeons' attention. For mild infection, changing dressing and infrared treatment can achieve good results. For moderate infection, one debridement and primary suture are enough. For severe infection, early application of VAC system can reduce the number of debridement and achieve good clinical outcome.

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The article introduces a factor that can cause early postoperative stage infection which is intractable complications.

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Three patients with fixation retained were shown to discuss whether instrumentation should be removed in deep infection.

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The report generalized effective therapeutics for mild, moderate and severe infection in early stage.

Synthesis of Natural Nano-Hydroxyapatite from Snail Shells and Its Biological Activity: Antimicrobial, Antibiofilm, and Biocompatibility

Hydroxyapatite nanoparticles (HAn) have been produced as biomaterial from biowaste, especially snail shells (Atactodea glabrata). It is critical to recycle the waste product in a biomedical application to overcome antibiotic resistance as well as biocompatibility with normal tissues. Moreover, EDX, TEM, and FT-IR analyses have been used to characterize snail shells and HAn. The particle size of HAn is about 15.22 nm. Furthermore, higher inhibitory activity was observed from HAn than the reference compounds against all tested organisms. The synthesized HAn has shown the lowest MIC values of about 7.8, 0.97, 3.9, 0.97, and 25 µg/mL for S. aureus, B. subtilis, K. pneumonia, C. albicans, and E. coli, respectively. In addition, the HAn displayed potent antibiofilm against S. aureus and B. subtilis. According to the MTT, snail shell and HAn had a minor influence on the viability of HFS-4 cells. Consequently, it could be concluded that some components of waste, such as snail shells, have economic value and can be recycled as a source of CaO to produce HAn, which is a promising candidate material for biomedical applications.