Effectiveness of 5-Pyrrolidone-2-carboxylic Acid and Copper Sulfate Pentahydrate Association against Drug Resistant Staphylococcus Strains

Bacterial resistance is an ongoing challenge for pharmacotherapy and pharmaceutical chemistry. Staphylococcus aureus is the bacterial species which makes it most difficult to treat skin and soft tissue infections and it is seen in thousands of hospitalization cases each year. Severe but often underrated infectious diseases, such as complicated nasal infections, are primarily caused by MRSA and S. epidermidis too. With the aim of studying new drugs with antimicrobial activity and effectiveness on drug resistant Staphylococcus strains, our attention in this study was drawn on the activity of a new association between two natural products: 5-pyrrolidone-2-carboxylic acid (PCA), naturally produced by certain Lactobacillus species, and copper sulfate pentahydrate (CS). The antimicrobial susceptibility test was conducted taking into account 12 different Staphylococcus strains, comprising 6 clinical isolates and 6 resistant strains. PCA 4%, w/w, and CS 0.002%, w/w, association in distilled water solution was found to have bactericidal activity against all tested strains. Antimicrobial kinetics highlighted that PCA 4%, w/w, and CS 0.002% association could reduce by 5 log10 viable bacterial counts of MRSA and oxacillin resistant S. epidennidis in less than 5 and 3 minutes respectively. Microscopic investigations suggest a cell wall targeting mechanism of action. Being very safe and highly tolerated, the natural product PCA and CS association proved to be a promising antimicrobial agent to treat Staphylococcus related infections.

The antibacterial activity of levofloxacin eye drops against staphylococci using an in vitro pharmacokinetic model in the bulbar conjunctiva

The incidence of fluoroquinolone-resistant staphylococcal isolates from the conjunctival sac is increasing. We compared pharmacological effects of levofloxacin (LVFX) against Staphylococcus epidermidis using an in vitro pharmacokinetic (PK) model simulating the concentration in the bulbar conjunctiva after applying eye drops of 0.5% and 1.5% LVFX. We used S. epidermidis conjunctival sac isolates [minimum inhibitory concentrations (MICs) of LVFX, 0.125 μg/mL]. LVFX-resistant strains were obtained from parental strains after culture with LVFX. The in vitro PK model simulated the concentration in the bulbar conjunctiva following three topical applications of 0.5% or 1.5% LVFX ophthalmic solution (0, 4, and 8 h) to rabbit eyes. Parental and LVFX-resistant strains were exposed to LVFX in the in vitro PK model, and changes in viable bacterial counts were evaluated for 12 h. The MICs of LVFX for the resistant isolates were 2-32 times higher than the parental strain, and those with MICs ≥2 ug/mL had mutations in the quinolone resistance-determining region. The PK model simulation predicts that 1.5% LVFX exerts bactericidal and bacteriostatic effects against strains with MICs of 0.125-2 and 4 μg/mL, respectively, whereas 0.5% LVFX would only be effective against strains with MICs of 0.125-1 μg/mL. The PK model predicts that the 1.5% LVFX ophthalmic solution exhibits a stronger bactericidal effect against resistant staphylococci in the bulbar conjunctiva than the 0.5% LVFX ophthalmic solution.

Persistent infection by Staphylococcus epidermidis in endodontic flare-up: a case report

Endodontic flare-ups are challenging situations and may result from selective growth of specific bacterial species; microbial cultures and antibiograms should be used to allow faster, successful management of refractory lesions. A 47-year-old man reported pain on percussion after uncomplicated retreatment of the maxillary left canine for prosthetic purposes. In the following days, pain dramatically increased, leading to removal of the filling and use of intracanal medication. After many unsuccessful attempts to resolve the problem, a microbial culture of the root canal detected the presence of Staphylococcus epidermidis. An antibiogram determined the best drug combination to control this infection: tetracycline (oxytetracycline hydrochloride, 500 mg orally) plus third-generation cephalosporin (ceftriaxone, 1 g intramuscularly). Once the infection was controlled, the root canal was obturated. There was a reduction in the area of radiolucency, and the patient reported no pain at a 2-year follow-up.

Staphylococcal LTA-Induced miR-143 Inhibits Propionibacterium acnes-Mediated Inflammatory Response in Skin

Staphylococcus epidermidis (S. epidermidis) plays a critical role in modulating cutaneous inflammatory responses in skin. Although S. epidermidis has been shown to co-colonize with Propionibacterium acnes (P. acnes) in acne lesions, it is unclear whether S. epidermidis is involved in the regulation of P. acnes-induced inflammatory responses. In this study, we demonstrated that S. epidermidis inhibited P. acnes-induced inflammation in skin. P. acnes induced the expression of interleukin-6 and tumor necrosis factor-α via the activation of toll-like receptor (TLR) 2 in both keratinocytes and mouse ears. Staphylococcal lipoteichoic acid activated TLR2 to induce miR-143 in keratinocytes, and miR-143, in turn, directly targeted 3' UTR of TLR2 to decrease the stability of TLR2 mRNA and then decreased TLR2 protein, thus inhibiting P. acnes-induced proinflammatory cytokines. The inhibitory effect of miR-143 was further confirmed in vivo as the administration of miR-143 antagomir into mouse ears abrogated the inhibitory effect of lipoteichoic acid on P. acnes-induced inflammation in skin. Taken together, these observations demonstrate that staphylococcal lipoteichoic acid inhibits P. acnes-induced inflammation via the induction of miR-143, and suggest that local modulation of inflammatory responses by S. epidermidis at the site of acne vulgaris might be a beneficial therapeutic strategy for management of P. acnes-induced inflammation.

Tender Cystic Structure on the Back in an Infant

A 1-year-old Hispanic boy with multiple congenital anomalies including a double-outlet right ventricle, significant scoliosis, kyphosis, and multiple hemivertebrae and hemilamina presented with recurrent febrile episodes. He was found to have Staphylococcus epidermidis meningitis, which persisted despite medical management. On physical examination, a 1×1-cm, tender, erythematous cystic structure with a purulent focus was discovered on the upper portion of his back (Figure 1). His mother noted that the structure was not present at birth, but there was a small red area at the time of delivery that had slowly developed into the lesion shown. T2-weighted sagittal magnetic resonance imaging showed a 4-mm sinus connection from the superficial cystic structure (white arrow) to another 2.4×1.5-cm cystic structure (black arrow) at the level of the hemivertebrae (Figure 2).

Pathological-Condition-Driven Construction of Supramolecular Nanoassemblies for Bacterial Infection Detection

A pyropheophorbide-α-based building block (Ppa-PLGVRG-Van) can be used to construct self-aggregated superstructures in vivo for highly specific and sensitive diagnosis of bacterial infection by noninvasive photoacoustic tomography. This in vivo supramolecular chemistry approach opens a new avenue for efficient, rapid, and early-stage disease diagnosis with high sensitivity and specificity.

Creation of Staphylococcal Mutant Libraries Using Transposon Tn917

Non-directed mutagenesis of the staphylococcal genome is a global approach that can be used to identify the genetic basis for phenotypes of interest as well as for identifying regulators of gene expression. One such approach that has been widely used in the study of S. aureus and S. epidermidis is transposon Tn917 mutagenesis to generate random libraries of mutants. This chapter describes the use of plasmid pLTV1 (containing Tn917-lac) to generate Tn917 transposon mutants. Through the use of temperature manipulation and antibiotic selection, staphylococcal strains harboring this plasmid can be effectively mutagenized to create random libraries amenable to subsequent phenotypic screening and identification of transposon insertion sites.

[Severe Ocular Infection in Elderly Patients with Dementia: a Case Study]

Purpose : To report 3 cases of severe ocular infection in elderly patients with dementia.

CASE REPORTS

Case 1 involved a 75-year-old man who presented after his wife noticed hyperemia and discharge in his right eye. Corneal infection with perforation was found. Wife-administered antibiotics healed the infection within 1 month. Case 2 involved a 97-year-old man who was referred to us after nursing-home staff members noticed redness and discharge in his right eye. Severe corneal infection with hypopyon was found. Following systemic and topical and antibiotics' administration by the nursing-home staff, the infectious keratitis healed within 2 weeks. Case 3 involved an 80-year-old woman referred to us from another clinic due to persistent epithelial defect in her left eye. Since the defect was accompanied by anterior uveitis and vitreous opacity, we suspected bacterial endophthalmitis. Following systemic and topical antibiotics' administration by family members, signs of infection diminished within 3 weeks. In all 3 cases, medical examination was difficult, topical eye-drop instillation by the patients themselves was impossible.

CONCLUSIONS

In elderly dementia patients, cognizance of infection, medical examination, and treatment are difficult. Support by family members or nursing-home staff is necessary to obtain improved outcomes.

[EFFECT OF INFECTION ON CAPSULE FORMATION AFTER BREAST IMPLANTS]

OBJECTIVE

To investigate the correlation between infection and capsular contracture by observing the effect of infection on the formation of the surrounding capsule after breast implants.

METHODS

Three healthy adult female Diannan small-ear pigs underwent augmentation mammaplasty using miniature implants, which were randomly divided into group A (12 nipples), group B (10 nipples), and group C (12 nipples). Staphylococcus epidermidis (SE ATCC12228 and SE RP62A, 1.2 x 10⁵ CFU/mL) was inoculated into the periprosthetics of groups B and C, and sterile PBS in group A before breast implants. Then the silica gel prosthesis was put, total 34 implants in 3 groups. After 13 weeks, the capsule was harvested to measure the capsular tension and weight. HE staining was used to observe the structure characteristics of the capsule and to measure the capsule thickness, Van-Gieson (VG) staining to observe the capsule collagen characteristics, and α-smooth muscle actin (α-SMA) immunocytochemistry staining to observe myofibroblasts in capsule.

RESULTS

Primary healing of incision was obtained, and 3 small-ear pigs showed stable life indication. The complete fibrous capsule was observed after 13 weeks in 3 groups. Capsule tension showed no significant difference among 3 groups (P > 0.05). Capsule weight was significantly greater in group C than in groups A and B (P < 0.05). HE staining showed that capsule structure of the 3 groups was similar with obvious dense layer and loose layer, and the capsule thickness was also significantly greater in group C than in groups A and B (P < 0.05), but no significant difference was found between groups A and B (P > 0.05). VG staining showed that collagenous fiber in the capsule were more compact in group C than in groups A and B. The α-SMA immunocytochemistry staining indicated the myofibroblasts in capsule were the most in group C.

CONCLUSION

Infection after breast implants has obvious impacts on the formation of the capsule, and there was a causal link between infection and capsular contracture.

An adaptive biointerface from self-assembled functional peptides for tissue engineering

A self-assembled peptide-based biointerface is demonstrated with triple functional layers that can significantly improve the tissue self-healing process or prevent biofilm-mediated chronic inflammation. This smart biointerface is composed of three functional moieties (i.e., a cell-adhesive peptide, an infectious environment-responsive peptide, and an antifouling hexaethylene glycol (HEG) layer), and the resulting interface coated onto prosthetic replacements can smartly respond to the surrounding physiological or pathological microenvironment.

Pulmonary Valvuloplasty by Autologous Pericardium in a Patient with Active Infectious Endocarditis and Osler's Disease

Osler's disease is a rare condition of autosomal dominant inheritance characterized by bleeding and telangiectasia of the skin and mucosal membranes. A few reports exist of open-heart surgery in patients with Osler's disease. Here, the case is presented of a successful pulmonary valvuloplasty using autologous pericardium to treat active infectious endocarditis of the pulmonary valve in a patient with Osler's disease. Such patients are at higher risk of bacteremia because of their chronic nasal bleeding or pulmonary arteriovenous fistula. In patients with Osler's disease, valuvloplasty using autologous pericardium is considered effective for preventing the later recurrence of IE.

The use of photodynamic therapy to treat hidradenitis suppurativa a review and critical analysis

Hidradenitis Suppurativa (HS) is an inflammatory disease that results in abscesses, keloids, and fistulas. Acne inversa is likely to result from aberrant cellular immunity and dysfunction of the hair follicle in which coagulase negative staphylococcus (CONS) and perhaps other bacteria appear e.g Corynebacterium sp.to play a role by creating biofilms and stimulating the immune system. One treatment that has been proposed for HS is photodynamic therapy. The cases series reported are small and not double blinded. As of October of 2104, 8 articles with 64 patients report success with photodynamic therapy using 5-aminolevulinic acid (PDT-ALA) or its methyl ester (PDT-MAL). One of these 8 reports noted superiority of the free methylene blue gel over niosomal methylene blue gel. Another report described success in a 27-patient trial using intralesional 5-aminolevulinic acid (ALA) in saline at a concentration of 1%. This was administered at a dose of 0.2 ml per cm3 and an HS fistula was irradiated by a continuous 630-nm laser diode through a 1-mm thick optical fiber to 1 Watt per cm3 for 3 minutes (180 Joules). However, 3 articles reported failure with PDT-ALA or pulse dye laser-mediated photodynamic therapy (PDL-PDT) and one article note 1 failure and 1 success. We suggest that it is the ability of PDT-ALA or PDT-MAL to break up the bio-film produced by CONS and other antibacterial effects that account for its success in treating HS in patients in whom bio-film plays a pivotal part of their pathogenesis. Other effects are also possible as well. Other mechanisms by which PDT may improve HS include cytotoxic effects, which cause selective cell necrosis, and immunomodulatory effects. The data suggests that if PDT is to be used, it should be with MAL or intralesional ALA. Note that there are a variety of causes of HS. These include hyperkeratosis of in the follicular infundibulum, aberrant cellular immunity, down regulations of defensins in stage III HS, and the infiltration of neutrophils, mast cells, plasma cells, and lymphocytes into the affected follicle, among others. However, it is likely that in individual cases one cause is primary and others secondary. In conclusion, PDT is not a first line treatment for HS but in some cases could be added as an adjuvant to therapies such as clindamycin and rifampin.

Pathology image of the month: death in a young adult with sickle cell disease

A 27-year-old African-American female with known sickle cell disease was admitted for sickle cell crisis and presumed sepsis. The patient's past medical history was complicated by multiple sickle cell-related complications, including seizures and multiple prior blood transfusions. Her hospital course included Staphylococcus epidermidis bacteremia, for which broad spectrum antibiotics were prescribed. On hospital day nine, the patient was found unresponsive and declared dead after unsuccessful efforts at resuscitation. An unlimited autopsy examination was conducted under authorization of the coroner. Findings included numerous pathologic features ascribed to sickle cell disease, including systemic siderosis and splenic atrophy [weight 10 gm (140±78)], fibrosis, and Gamna Gandy nodules. Additional autopsy findings included cardiomegaly with a heart weight of 450 gm (312±78), right atrial and right ventricular chamber dilatation, and hepatomegaly with a liver weight of 2650 gm (1475±362). The image below demonstrates microscopic examination of the lung parenchyma.

Tolerability and efficacy of long-term treatment with daptomycin, ceftazidime and colistin in a patient with a polymicrobial, multidrug-resistant prosthetic joint reinfection: a case report

INTRODUCTION

Prosthetic joint infections are severe complications of joint implants. Further complications arise when polymicrobial and/or multidrug-resistant microorganisms are involved. Currently, there are limited data on the management of these infections and on the tolerability of long-term treatment with daptomycin, ceftazidime and colistin.

CASE PRESENTATION

A 55-year-old Caucasian woman who had a right hip prosthesis removed 1 year prior because of infection was admitted for prosthesis reimplantation. On admission at our hospital, anamnesis regarding etiology and management of prosthesis infection was not available. On clinical, laboratory findings and imaging studies infection was not suspected. A hip prosthesis was reimplanted. At surgery, histopathological and microbiological investigations were not taken. Three weeks after reimplantation, surgical site infection due to Enterobacter cloacae was diagnosed and oral ciprofloxacin was prescribed. Four days later, a periprosthesis fluid collection was evidenced and a percutaneous needle aspirate grew Staphylococcus epidermidis and S. haemolyticus. Enterobacter genome was also detected from the same sample. Teicoplanin and meropenem were added to ciprofloxacin without clinical improvement. Moreover, acetabular cup dislocation was documented. She underwent prosthesis explantation, debridement, and positioning of an antimicrobial mixed spacer. From the intraoperatory cultures S. epidermidis and Acinetobacter baumannii were grown. Daptomycin, ceftazidime, colistin and rifampin were administered. Four days later, rifampin was stopped due to a suspected liver toxicity. While undergoing therapy she presented recurrent episodes of wound dehiscence and on the 22nd week of treatment a further surgical debridement was performed, upon which the spacer was removed. At this time, intraoperative cultures resulted negative. Three months later, after a total of 8 months, antimicrobials were interrupted. Subsequently, a femoral transcondylar traction was positioned, and 3 weeks later a new prosthesis was reimplanted. At over 1 year after reimplantation she is well.

CONCLUSIONS

Our findings suggest that microbiologic investigations are mandatory even when prosthetic joint infection is not suspected. Molecular methods for identification of microorganisms can be used in addition to conventional cultures especially when patients are under antibiotic treatment. Daptomycin, ceftazidime and colistin can be administered for several months without side effects. Guidelines specifically addressing the diagnosis and the management of polymicrobial, multidrug-resistant prosthetic joint infections need to be developed.

Early and late outcomes after reoperation for prosthetic valve endocarditis

OBJECTIVE

Prosthetic valve endocarditis remains a challenging complication after heart valve replacement. To identify predictive risk factors, we have reviewed 30 patients who underwent surgery for prosthetic valve endocarditis between March 1986 and May 1999.

METHODS

There were 15 men and 15 women (mean age 51 years). Prosthetic valve endocarditis was classified as early (< or = 1 year after operation) in 10 cases, and as late in the other 20 cases. The most common indication for surgery was moderate to severe congestive heart failure due to prosthetic valve dysfunction in 21 (70%) patients. The average follow-up period was 6.5 years, with a range of 0.3 to 14.1 years.

RESULTS

The most common microorganism was Staphylococcus epidermidis in both patients with early (50%) and late prosthetic valve endocarditis (25%). The in-hospital mortality was 13.3% (4/30). There were six late deaths. The actuarial survival at 5 years was 78% and 66% at 10 years. An early onset of prosthetic valve endocarditis was the only significant determinant of both in-hospital mortality (p = 0.005) and overall mortality (p = 0.021). Emergency surgery had a statistically significant relationship with in-hospital mortality (p = 0.045). No significant influence on mortality after reoperation for prosthetic valve endocarditis was found in age, sex, valve position, antecedent native valve endocarditis, or in the type of pathological findings (ring abscess, valve dehiscence, and vegetation).

CONCLUSION

Early onset of prosthetic valve endocarditis and emergency surgery were important risk factors for mortality due to prosthetic valve endocarditis.

TcaR-ssDNA complex crystal structure reveals new DNA binding mechanism of the MarR family proteins

The teicoplanin-associated locus regulator (TcaR) regulates gene expression of proteins on the intercellular adhesion (ica) locus involved in staphylococci poly-N-acetylglucosamine biosynthesis. The absence of TcaR increases poly-N-acetylglucosamine production and promotes biofilm formation. Until recently, the mechanism of multiple antibiotic resistance regulator family protein members, such as TcaR, was restricted to binding double-stranded DNA. However, we recently found that TcaR strongly interacts with single-stranded DNA, which is a new role for this family of proteins. In this study, we report Staphylococcus epidermidis TcaR–single-stranded DNA complex structures. Our model suggests that TcaR and single-stranded DNA form a 6₁-symmetry polymer composed of TcaR dimers with single-stranded DNA that wraps outside the polymer and 12 nt per TcaR dimer. Single-stranded DNA binding to TcaR involves a large conformational change at the DNA binding lobe. Several point mutations involving the single-stranded DNA binding surface validate interactions between single-stranded DNA and TcaR. Our results extend the novel role of multiple antibiotic resistance regulator family proteins in staphylococci.

Development of luminescent pH sensor films for monitoring bacterial growth through tissue

Although implanted medical devices (IMDs) offer many benefits, they are susceptible to bacterial colonization and infections. Such infections are difficult to treat because bacteria could form biofilms on the implant surface, which reduce antibiotics penetration and generate local dormant regions with low pH and low oxygen. In addition, these infections are hard to detect early because biofilms are often localized on the surface. Herein, an optical sensor film is developed to detect local acidosis on an implanted surface. The film contains both upconverting particles (UCPs) that serve as a light source and a pH indicator that alters the luminescence spectrum. When irradiated with 980 nm light, the UCPs produce deeply penetrating red light emission, while generating negligible autofluorescence in the tissue. The basic form of the pH indicator absorbs more of upconversion luminescence at 661 nm than at 671 nm and consequently the spectral ratio indicates pH. Implanting this pH sensor film beneath 6-7 mm of porcine tissue does not substantially affect the calibration curve because the peaks are closely spaced. Furthermore, growth of Staphylococcus epidermidis on the sensor surface causes a local pH decrease that can be detected non-invasively through the tissue.

Composition and properties of silver-containing calcium carbonate-calcium phosphate bone cement

The introduction of silver, either in the liquid phase (as silver nitrate solution: Ag(L)) or in the solid phase (as silver phosphate salt: Ag(S)) of calcium carbonate-calcium phosphate (CaCO3-CaP) bone cement, its influence on the composition of the set cement (C-Ag(L) and C-Ag(S) cements with a Ca/Ag atomic ratio equal to 10.3) and its biological properties were investigated. The fine characterisation of the chemical setting of silver-doped and reference cements was performed using FTIR spectroscopy. We showed that the formation of apatite was enhanced from the first hours of maturation of C-Ag(L) cement in comparison with the reference cement, whereas a longer period of maturation (about 10 h) was required to observe this increase for C-Ag(S) cement, although in both cases, silver was present in the set cements mainly as silver phosphate. The role of silver nitrate on the setting chemical reaction is discussed and a chemical scheme is proposed. Antibacterial activity tests (S. aureus and S. epidermidis) and in vitro cytotoxicity tests (human bone marrow stromal cells (HBMSC)) showed that silver-loaded CaCO3-CaP cements had antibacterial properties (anti-adhesion and anti-biofilm formation) without a toxic effect on HBMSC cells, making C-Ag(S) cement a promising candidate for the prevention of bone implant-associated infections.

Crystallization and preliminary X-ray diffraction analysis of the DNA-binding domain of the response regulator SaeR from Staphylococcus epidermidis

SaeR is the response regulator of the SaeRS two-component signal transduction system, which is involved in regulating bacterial autolysis and biofilm formation. SaeR comprises an N-terminal receiver domain and a C-terminal effector domain. The effector domain possesses DNA-binding and transactivation functions. Here, the effector domain of SaeR from Staphylococcus epidermidis was purified and crystallized using the sitting-drop vapour-diffusion method. The crystals diffracted to a resolution of 2.15 Å and belonged to space group P2(1)2(1)2(1), with unit-cell parameters a = 34.20, b = 53.78, c = 111.66 Å. Determining the structure will provide insights into the mechanisms underlying DNA binding.

Functional polyelectrolyte multilayer membranes for water purification applications

A diverse set of supported multilayer assemblies with controllable surface charge, hydrophilicity, and permeability to water and solute was fabricated by pressure driven permeation of poly(sodium 4-styrenesulfonate) (PSS) and poly(diallyldimethylammonium chloride) (PDDA) solution through poly(ethylene terephthalate) (PET) track-etched membranes. The polyelectrolyte multilayer fabrication was confirmed by means of FTIR, SEM, AFM, ellipsometry, zetapotential, and contact angle characterization. The prepared membranes were characterized in terms of their pure water permeability, flux recovery, and resistance to organic and biofouling properties. The antifouling behavior of the membranes was assessed in terms of protein adsorption and antibacterial behavior. Finally, the membranes were tested for rejection of selected water soluble dyes to establish their usefulness for organic contaminant removal from water. The membranes were highly selective and capable of nearly complete rejection of congo red with sufficiently high fluxes. The feasibility of regenerating the prepared membranes fouled by protein was also demonstrated and good flux recovery was obtained. In summary, the multilayer approach to surface and pore modification was shown to enable the design of membranes with the unique combination of desirable separation characteristics, regenerability of the separation layer, and antifouling behavior.

Anti-infective and osteointegration properties of silicon nitride, poly(ether ether ketone), and titanium implants

Silicon nitride (Si(3)N(4)) is an industrial ceramic used in spinal fusion and maxillofacial reconstruction. Maximizing bone formation and minimizing bacterial infection are desirable attributes in orthopedic implants designed to adhere to living bone. This study has compared these attributes of Si(3)N(4) implants with implants made from two other orthopedic biomaterials, i.e. poly(ether ether ketone) (PEEK) and titanium (Ti). Dense implants made of Si(3)N(4), PEEK, or Ti were surgically implanted into matching rat calvarial defects. Bacterial infection was induced with an injection of 1×10(4)Staphylococcus epidermidis. Control animals received saline only. On 3, 7, and 14days, and 3months post-surgery four rats per time period and material were killed, and calvariae were examined to quantify new bone formation and the presence or absence of bacteria. Quantitative evaluation of osteointegration to adjacent bone was done by measuring the resistance to implant push-out (n=8 rats each for Ti and PEEK, and n=16 rats for Si(3)N(4)). Three months after surgery in the absence of bacterial injection new bone formation around Si(3)N(4) was ∼69%, compared with 24% and 36% for PEEK and Ti, respectively. In the presence of bacteria new bone formation for Si(3)N(4), Ti, and PEEK was 41%, 26%, and 21%, respectively. Live bacteria were identified around PEEK (88%) and Ti (21%) implants, whereas none were present adjacent to Si(3)N(4). Push-out strength testing demonstrated statistically superior bone growth onto Si(3)N(4) compared with Ti and PEEK. Si(3)N(4) bioceramic implants demonstrated superior new bone formation and resistance to bacterial infection compared with Ti and PEEK.

A rat model of central venous catheter to study establishment of long-term bacterial biofilm and related acute and chronic infections

Formation of resilient biofilms on medical devices colonized by pathogenic microorganisms is a major cause of health-care associated infection. While in vitro biofilm analyses led to promising anti-biofilm approaches, little is known about their translation to in vivo situations and on host contribution to the in vivo dynamics of infections on medical devices. Here we have developed an in vivo model of long-term bacterial biofilm infections in a pediatric totally implantable venous access port (TIVAP) surgically placed in adult rats. Using non-invasive and quantitative bioluminescence, we studied TIVAP contamination by clinically relevant pathogens, Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Staphylococcus epidermidis, and we demonstrated that TIVAP bacterial populations display typical biofilm phenotypes. In our study, we showed that immunocompetent rats were able to control the colonization and clear the bloodstream infection except for up to 30% that suffered systemic infection and death whereas none of the immunosuppressed rats survived the infection. Besides, we mimicked some clinically relevant TIVAP associated complications such as port-pocket infection and hematogenous route of colonization. Finally, by assessing an optimized antibiotic lock therapy, we established that our in vivo model enables to assess innovative therapeutic strategies against bacterial biofilm infections.

Effect of strain rate on the mechanical properties of Staphylococcus epidermidis biofilms

The quantification of biofilm mechanical properties can serve as a basis for understanding biofilm resilience and for developing biofilm control strategies. One aspect of tensile testing that is likely to be important for a viscoelastic material such as bacterial biofilm, but unfortunately is often overlooked (i.e., not controlled or reported), is the strain rate used during testing. Thus, we performed tensile testing on intact S. epidermidis biofilms using the microcantilever method at 12 strain rate values ranging over approximately 3 orders of magnitude (0.013-9.07 s(-1)). Ultimate or cohesive strength, elastic modulus, and toughness increased with increasing strain rate and approached a plateau at approximately 1.3 s(-1). Failure strain, on the other hand, did not exhibit any trend with strain rate. Given that the mean values of some parameters increased by as much as 1 order of magnitude over the strain rate range used in this work, we suggest that the strain rate during tensile testing should be carefully controlled and reported to facilitate comparisons among different studies. Furthermore, the quantitative expressions developed in this work that relate mechanical property values with strain rate may be useful for modeling the deformation of bacterial biofilms under applied loads.

Microbiological stability of solutions containing local anesthetics and opioids in closed infusion systems used for epidural analgesia

Nine solutions containing opiod analgesics and local anesthetics as typically use in epidural catheters were tested for antimicrobial stability. Administration via a pefusor syringe requires several refill processes. It was shown that repetitive refilling of the syringes did not result in any microbiological contamination.

Antibiotic pretreatment of heart valve prostheses to prevent early prosthetic valve endocarditis

BACKGROUND AND AIM OF THE STUDY

Prosthetic valve endocarditis (PVE), a rare but major complication after heart valve replacement surgery, has potentially catastrophic consequences despite maximal treatment. Thus, preventive measures are essential. The study aim was to investigate the effect of pretreating heart valve prostheses with the antibiotics baneomycin and daptomycin, with and without surgical sealant fibrin glue as a drug-releasing substance. The biocompatibility of baneocin and daptomycin was also investigated.

METHODS

Samples of polyethylene terephthalate (PTE), as used for the sewing cuffs of prosthetic heart valves, were tested; untreated samples served as controls. All samples were contaminated with Staphylococcus epidermidis, and colony-forming units (CFUs) then counted. Cytotoxicity tests were performed using the MTT-assay to evaluate the effects of baneomycin and daptomycin on cell proliferation and wound healing.

RESULTS

Untreated and fibrin glue-coated samples were directly infected with a bacterial count of 2.82 +/- 0.63 x 10(5) CFU/ml and 2.80 +/- 1.07 x 10(5) CFU/ml, on average. Baneocin-impregnated samples were sterile for 1.9 +/- 0.38 days, with a subsequent bacterial count of 2.26 +/- 0.6 x 10(5) CFU/ml, while daptomycin-impregnated samples were sterile for 2.9 +/- 0.38 days, with a subsequent bacterial count of 1.81 +/- 0.53 x 10(5) CFU/ml. Samples coated with a fibrin glue-baneocin mixture were sterile for 3.14 +/- 0.38 days, after which the bacterial count was 0.74 +/- 0.47 x 10(5) CFU/ml. After coating with a fibrin glue-daptomycin mixture, samples were sterile for 7.0 +/- 0.58 days, and the bacterial count was 0.70 +/- 0.56 x 10(5) CFU/ml.

CONCLUSION

In this in-vitro study, the pretreatment of prosthetic heart valves with antibiotics reduced the risk of bacterial adhesion and consequent infection. The combination of antibiotics with fibrin glue prolonged this preventive effect, with baneocin demonstrating a better biocompatibility than daptomycin. On the basis of its antibacterial efficacy, daptomycin appears to be a more suitable antibiotic to prevent early PVE with Gram-positive bacteria. The soaking of prosthetic heart valves in antibiotic solutions prior to implantation, in combination with fibrin glue in cases of suspected endocarditis, can prevent the development of early PVE. This preventive strategy should be investigated for use as a standard procedure in clinical practice.

Methicillin resistant Staphylococcus epidermidis

Staphylococcus epidermidis is an emerging nosocomial pathogen. Due to its increasing incidence in many countries of the world it is a burning issue now a day. There is marked geographic variation in prevalence of methicillin resistant Staphylococcus epidermidis. Though it as is an endogenous human skin flora, it is therefore easily transmissible in the hospital environment well as in a community. Skin of patients and health care workers, medical equipment, clothing of personnel and environment surfaces can be sources of antibiotic-resistant S. epidermidis strains. This opportunistic pathogen causing different types of infections linked to implanted medical devices especially in immunocompromised patients. Early and specific diagnosis is important to ensure a favourable outcome. So Staphylococcus epidermidis found in culture should not always be ignored as contaminant and proper medical treatment and preventive guidelines should be applied against this alarming pathogen.

Echocardiography in detecting implantable cardioverter defibrillator lead endocarditis: case report

Lead endocarditis is an infrequent but potentially lethal complication of implantable cardioverter defibrillator (ICD) implantation. We report a case of a 53-year-old man with ICD who was admitted to our hospital because of fever, chills, shivering, headache and malaise. Transthoracic echocardiography detected a structure highly suspect of vegetation located on the ICD lead. Transesophageal echocardiography showed a 20x12 mm mobile vegetation attached to the ICD lead in the right atrium. The infection was caused by methicillin-resistant Staphylococcus epidermidis (MRSE), which was isolated from blood cultures. Treatment consisted of surgical removal of the ICD lead and placement of new epicardial ICD leads. Three years afterwards, the patient remained asymptomatic. To our knowledge, this is the first such case reported from Croatia.

Reduction in external ventricular drain infection rate. Impact of a minimal handling protocol and antibiotic-impregnated catheters

INTRODUCTION

Many strategies have been developed with the aim of reducing external ventricular drain-related infections. Antibiotic-impregnated catheters are one of them.

MATERIAL AND METHODS

We report 648 cases of external ventricular drain from a total of 534 patients treated at the Virgen del Rocío Hospital between 1995 and 2006. Three subgroups were considered: group 1 included patients treated between 1995 and 2000, as well as a total of 190 external ventricular drains and 59 cases of infection (31.05%); group 2, with patients treated between 2000 and 2004 and managed with a minimal handling protocol, included 210 external ventricular drains and nine cases of infection (4.29%); and group 3, treated between 2004 and 2006, with 248 external ventricular drains and six cases of infection (2.41%). This latter subgroup included patients managed with a minimal handling protocol and antibiotic-impregnated catheters.

RESULTS

Infection rate was 17% when non-antibiotic-impregnated catheters were employed and 2.41% when antibiotic-impregnated catheters were inserted (p < 0.001). This difference was statistically significant before and after the introduction of a minimal handling protocol, with percentages of 5.31% and 3.27%, respectively (p < 0.001; odds ratio 0.08; absolute risk reduction 27.26%). However, no statistically significant difference was observed in infection rate when the impact of a minimal handling protocol was considered: 4.29% when only the protocol was introduced and 2.41% when both the protocol and antibiotic-impregnated catheters were used (p > 0.05).

CONCLUSION

Minimal handling protocols constitute an essential strategy in the reduction of external ventricular drain-related infections. Besides that, the use of antibiotic-impregnated catheters may reduce infection-related hospital costs.

Chemical and antimicrobial treatments change the viscoelastic properties of bacterial biofilms

Changes in the viscoelastic material properties of bacterial biofilms resulting from chemical and antimicrobial treatments were measured by rheometry. Colony biofilms of Staphylococcus epidermidis or a mucoid Pseudomonas aeruginosa were subjected to a classical creep test performed using a parallel plate rheometer. Data were fit to the 4-parameter Burger model to quantify the material properties. Biofilms were exposed to the chloride salts of several common mono-, di-, and tri- valent cations, and to urea, industrial biocides, and antibiotics. Many of these treatments resulted in statistically significant alterations in the material properties of the biofilm. Multivalent cations stiffened the P. aeruginosa biofilm, while ciprofloxacin and glutaraldehyde weakened it. Urea, rifampin, and a quaternary ammonium biocide weakened the S. epidermidis biofilm. In general, there was no correspondence between the responses of the two different types of biofilms to a particular treatment. These results underscore the distinction between the killing power of an antimicrobial agent and its ability to alter biofilm mechanical properties and thereby influence biofilm removal. Understanding biofilm rheology and how it is affected by chemical treatment could lead to improvements in biofilm control.

The pseudomeningocoele that wasn't: case report of an adult who presented with a late infection of an implant

This case report describes an unusual case of a 55-year-old male, who presented with what appeared to be a pseudomeningocoele. The patient suffered a skull fracture secondary to a direct blow almost 30 years prior, and had been repaired with a calvarial implant at that time. He had been symptom free for most of that time, until he presented to our institution with a bulging cyst in his left frontal region. Computed tomography revealed a calvarial defect at the site of the cyst and a presumptive diagnosis of pseudomeningocoele was made. As part of his treatment, the patient underwent a lumbar puncture and lumbar peritoneal shunt. These procedures, although temporarily beneficial, ultimately proved unsuccessful in permanently decreasing the size of the cyst. After all conservative measures were exhausted, the team surgically explored the patient: while no communication between the cerebrospinal fluid and cyst could be found, which would be expected in a pseudomeningocoele, there was fibrinous exudates on the implant surface. Tissue cultures showed Staphylococcus epidermidis. This case emphasises the importance of surgical exploration to make a correct diagnosis, as in this case of a sub-clinical calvarial implant infection 30 years after insertion of the implant.

[Cylindrical patch repair for circumferential subvalvular abscess due to prosthetic valve endocarditis]

A 51-year-old male underwent aortic valve replacement and vascular prosthesis implantation due to an aneurysm of the ascending aorta combined with aortic regurgitation caused by the bicuspid aortic valve. Semi-emergency surgery was performed due to severe paravalvular leakage with prosthetic valve endocarditis 16 months after the 1st operation. The circumferential annular abscess cavities were closed with a cylindrical patch, and a mechanical valve was installed on the upper edge of the sutured cylindrical patch. A vascular prosthesis was reimplanted to the ascending aorta. Use of the cylindrical patch provides a good exposure of operative field to close circumferential annular abscess cavity.

Osteomyelitis of the pubic symphysis after spontaneous vaginal delivery

Osteomyelitis ossis pubis is a painful disorder. It is rare following a normal vaginal delivery. In two cases, the diagnosis was verified by an ultrasound-guided needle aspiration postpartum. Both recovered after treatment with relevant antibiotics. The condition is easily misinterpreted as one of more common disorders like pelvic girdle pain, inflammation, diastasis or distortion of the pubic symphysis joint. If not recognised and treated, the condition can have severe consequences.

Prevention of early vascular graft infection using regional antibiotic release

BACKGROUND

Infections after prosthetic replacement of the aorta remain a serious and life-threatening complication. The only appropriate treatment is the surgical removal of the infected prosthesis. Accordingly, there is a need for new procedures to prevent the infection of vascular prostheses. This in vitro experiment investigated the effect of the pretreatment of vascular prostheses with antibiotics (daptomycin or baneocin) and the effect of antibiotics combined with fibrin sealant as possible prophylaxis of perioperative graft infection.

METHODS

Untreated prostheses served as controls. Pretreated prostheses of double woven velour vascular grafts were contaminated with Staphylococcus epidermidis, and colony-forming units were counted each day (CFU/mL).

RESULTS

The period of sterility differed significantly as a function of the pretreatment. Uncoated prostheses were immediately non-sterile and exhibited 2.63 ± 0.61 × 10(5) CFU/mL. Baneocin pretreatment resulted in sterility for 1.7 ± 0.6 (95% confidence interval (CI) 1.0-2.4) d before we detected 2.14 ± 0.57 × 10(5) CFU/mL on the prostheses. Pretreatment with daptomycin yielded 2.9 ± 0.4 (CI 2.6-3.2) and fibrin sealant/baneocin compound yielded 3.1 ± 0.3 (CI 2.9-3.3) d of sterility, after which 1.81 ± 0.86 × 10(5) CFU/mL and 1.04 ± 0.77 × 10(5) CFU/mL were recorded. Finally, pretreatment with fibrin sealant/daptomycin led to sterility for 7.1 ± 0.3 (CI 6.9-7.3) d, after which 0.77 ± 0.60 × 10(5) CFU/mL were observed on the prostheses.

CONCLUSIONS

The risk of vascular graft infection is reduced by pretreating the prostheses with antibiotics. The antibiotic/fibrin compound exhibited an effect of delayed antibiotic release. Vascular prostheses should therefore be pretreated with antibiotic solution to reduce bacterial adhesion. This procedure might be an effective prophylaxis for perioperative vascular graft infection and provides suitable protection for the prosthetic material.

Sinus of valsalva pseudoaneurysm and mechanical aortic valve endocarditis

We present the case of a 54-year-old male with a St. Jude aortic valve replacement who presented with fever and a new diastolic murmur. An echocardiogram identified a pseudoaneurysm that appeared to originate from the left sinus of Valsalva. In anticipation of open valve surgery, a 64-slice computed tomographic (CT) angiogram was performed to characterize the size and location of the pseudoaneurysm. In addition, the CT scan was able to rule out significant coronary artery disease and obviate the need to perform a potentially high-risk catheterdirected angiogram in the setting of an infected pseudoaneurysm.

[Infectious complications of reconstructive operations on carotid arteries in atherosclerotic stenoses]

Analysed herein are the outcomes of a total of 2,240 reconstructive operations on carotid arteries (CA) performed in patients presenting with CA stenosis. Twenty-two (0.98%) patients were found to have developed infectious complications with the involvement of the reconstructed zone. Once suppuration had occurred sixteen patients were subjected to autovenous prosthetic repair of the internal carotid artery (ICA), with a further four cases having endured prosthetic reconstruction with a portion of the external CA, and the remaining two patients sustained ligation of the ICA. In the immediate postoperative period, two deaths had occurred, with recurrent infections accompanied and followed by the development of arrosive haemorrhage observed in two cases. The most commonly encountered microbial agents responsible for suppuration were largely staphylococci and streptococci, as well as Escherichia coli. The preoperative and postoperative prevention with antibiotics is obligatory. In order to assess the condition of the carotid arteries and involvement thereof into the infectious process it is necessary to rely upon the findings of ultrasonographic scanning of soft tissues of the neck in a combination with duplex scanning of carotid arteries. Early aggressive surgical policy consisting in extended surgical debridement of the infectious wound, reconstruction of the CA with autologous tissue aimed at preserving cerebral blood supply, and targeted antibiotic therapy make it possible in the majority of cases to obtain positive therapeutic outcomes.

Dexamethasone suppresses interleukin-22 associated with bacterial infection in vitro and in vivo

Interleukin (IL)-22 production triggered by innate immune mechanisms has been identified as key to efficient intestinal anti-bacterial host defence and preservation of homeostasis. We hypothesized that glucocorticoid therapy may impair IL-22 expression, which should promote intestinal epithelial damage with the potential of subsequent bacterial translocation. High-dose corticosteroid therapy in Crohn's disease has been associated with an increased rate of abscess formation and ultimately with a higher risk of developing postoperative infectious complications, including abdominal sepsis. Thus, we sought to investigate effects of the prototypic glucocorticoid dexamethasone on IL-22 production in the context of bacterial infection. Enhanced IL-22 plasma levels were detectable in rat sepsis. Moreover, heat-inactivated Staphylococcus epidermidis, used as a prototypic activator of innate immunity, induced robust production of IL-22 by human peripheral blood mononuclear cells (PBMC). Here, we report for the first time that dexamethasone mediates remarkable suppression of IL-22 as detected in S. epidermidis-activated PBMC and rat sepsis, respectively. The data presented herein suggest that insufficient IL-22 function may contribute to impaired intestinal host defence in the context of corticosteroid therapy.

[Infective endocarditis on probe of pacemaker]

Infective endocarditis is an uncommon but potentially lethal complication of permanent cardiac pacing. Infection is mainly caused by local contamination during the implantation procedure. The most frequently detected causative microorganisms were staphylococci. The clinical presentation is often atypical causing prolonged diagnostic delay. Bacteriological data and visualisation of neostructures consistent with vegetations on transoesophageal echocardiography, strongly suggest pacemaker lead infection. Management is based on a combined approach using both prolonged antibiotic treatment and early complete device explantation. Percutaneous techniques are currently the method of choice for lead extraction but it is not without possible complications. Antibiotic prophylaxis in order to reduce infection risk related to pacemaker implantation is widely recommended.

[Case of Staphylococcus epidermidis endocarditis with a bacterial vegetation suspected by intraoperative alternating pulse]

We report here a case of Staphylococcus epidermidis endocarditis with bacterial vegetation which was suspected by intraoperative alternating pulse on arterial pressure monitoring. A 65-year-old man was diagnosed as lumbar spinal canal stenosis and scheduled for operation. Preoperatively, he had chronic renal failure, mild aortic valve stenosis, and moderate mitral valve regurgitation. Neither inflammatory signs nor vegetations on TEE were observed preoperatively. General anesthesia was induced with propofol and vecuronium, and maintained with oxygen (33%), nitrous oxide and sevoflurane. Two hours after the beginning of operation, alternating pulse was observed suddenly on arterial pressure waves without marked change in hemodynamic parameters. The operation was performed uneventfully and alternating pulse disappeared after changing from prone position to supine. Using a transesophageal echocardiography, large-sized bacterial vegetation (22 x 17 mm) was found in the left ventricle. Second operation was performed to remove vegetation at three weeks after first operation. Alternating pulse is generally considered as a sign of severe left ventricular dysfunction such as dilated cardiomyopathy and aortic stenosis. Therefore, we should be careful about pulse disorder during operation for the patient who is in the state of severe heart failure.

[A pilot study on the proteome of cerebrospinal fluid of Staphylococcus epidermidis meningitis in children]

OBJECTIVE

Bacterial meningitis is a kind of central nervous system infection with a high incidence, disability and fatality in children. Prompt diagnosis and treatment are associated with an improved prognosis. Low positive rate of bacterial cultures of the cerebrospinal fluid (CSF) makes it difficult to make a definite diagnosis. This experiment aimed to investigate a proteome profile of normal CSF of Chinese children by two-dimensional polyacrydamide gel electrophoresis (2-DE), and to sieve the disease-specific proteins of Staphylococcus epidermidis meningitis (SeM) to provide basis for early diagnosis and treatment of SeM.

METHODS

Four mL CSF samples were obtained respectively from SeM and normal children. The separated proteins with immobile pH gradient (IPG) 2-DE technology and protein spots were visualized by Coomassie Brilliant Blue staining. The stained 2-DE gels were scanned on the Imagescanner and pictures were obtained through Labscan software. The images were analyzed with PDQuest software and the differences of protein spots were compared between the SeM and normal children.

RESULTS

Mean protein spots of the 2-DE gels were 438 and 425 in the SeM and normal groups respectively. Twenty-five protein spots only occurred in normal CSF and 12 spots only occurred in the SeM group. The expression of 6 protein spots showed up-regulation and that of 19 showed down-regulation in the SeM group compared with that in the normal group.

CONCLUSIONS

A 2-DE profile of CSF proteome was successfully established in SeM and normal children through proteomic technique. By the differentiated analysis of these CSF 2-DE gels, the differences of CSF proteome profiles were found between SeM and normal children. Future analysis and identification of these spots will contribute to find out the disease specific proteins of SeM and to provide basis for early diagnosis and therapy of this disorder.