Perichondritis and auricular cellulitis related to piercings as first manifestation of monkeypox

INTRODUCTION

Pinna infections are usually due to Staphylococcus aureus infection. It is common for the patient to have had an earring in the area of infection. Monkeypox infection has gone from being an endemic infection to a worldwide health emergency.

CASE SUMMARY

In this article we present five cases of monkeypox earring infection of the pinna and what common features we have seen that differentiate them from Staphylococcus aureus infection.

DISCUSSION

Symptoms of monkeypox include general malaise, fever with uni- or bilateral lymphadenopathy, and then the appearance within one or two days of skin lesions, we want to alert he otolaryngologist and the medical society to the possibility the diagnostic possibility of monkeypox in patients with an auricular perichondritis.

A pilot study of mitochondrial response to an in vivo prosthetic joint Staphylococcus aureus infection model

Prosthetic joint infections (PJI) are associated with orthopaedic morbidity and mortality. Mitochondria, the "cell's powerhouses," are thought to play crucial roles in infection response and in increased risk of sepsis mortality. No current research discusses PJI's effect on mitochondrial function and a lack of understanding of immune-infection interactions potentially hinders patient care. The purpose of this pilot study was to evaluate the impact of simulated PJI on local tissue mitochondrial function. Using an established prosthetic implant-associated in vivo model, tissues were harvested from the surgical limb of a methicillin-sensitive Staphylococcus aureus implant-associated infection group (n = 6) and compared to a noninfected group (n = 6) at postoperative day (POD) 21. Using mitochondrial coupling assays, oxygen consumption rate and extracellular acidification rate were assessed in each group. Electron flow through mitochondrial complexes reflected group activity. Electron Paramagnetic Resonance (EPR) spectrometry measured the oxidizing potential of serum samples from infected versus noninfected groups. On POD21, colony-forming units per gram of tissue showed 5 × 109 in the infected group and 101 in the noninfected group (p < 0.0001). Maximal respiration and oxygen consumption due to adenosine triphosphate synthesis were significantly lower in isolated mitochondria from infected limbs (p = 0.04). Both groups had similar complex I, III, IV, and V activity (p > 0.1). Infected group EPR signal intensity reflecting reactive oxygen species levels was 1.31 ± 0.30 compared to 1.16 ± 0.28 (p = 0.73) in the noninfected group. This study highlights PJI's role in mammalian cell mitochondrial dysfunction and oxidative tissue damage, which can help develop interventions to combat PJI.

Oral minocycline as systemic therapy for uncomplicated venous access device-related bloodstream infection with coagulase-negative staphylococci after allogeneic hematopoietic cell transplantation

BACKGROUND

Venous access device-related bloodstream infection (VAD-BSI) with coagulase-negative staphylococci (CoNS) is a common complication after allogeneic hematopoietic cell transplantation (alloHCT). Standard systemic antimicrobial therapy for uncomplicated VAD-BSI with methicillin-resistant CoNS consists of intravenous (IV) vancomycin (vanco). This requires hospitalization, needs new competent venous access, exposes patients to potential toxicity (mainly renal) and increases the risk of commensal flora dysbiosis with selection of vanco-resistant enterococci. Combined with VAD management (removal or antibiotic locks), oral minocycline (mino) has been evaluated as an alternative systemic therapy for the treatment of uncomplicated VAD-BSIs with CoNS at our center, primarily when the reference treatment with IV vanco was not possible (renal failure or allergy) or when hospitalization was refused by patients. Here, we retrospectively report our single center experience with this mino-based approach.

PATIENTS AND METHODS

From January 2012 to December 2020, 24 uncomplicated VAD-BSIs with CoNS in 23 alloHCT patients were treated with oral mino as systemic antibiotic therapy in combination with VAD management. VAD were implantable ports (n = 17), tunneled catheter (n = 1) or PIC-lines (n = 6). Staphylococci were S. epidermidis (n = 21) or S. haemolyticus (n = 3). Mino was administered with a loading dose of 200 mg followed by 100 mg BID for 7-14 days. For 8 VAD-BSIs, patients were initially treated with IV vanco for the first 1-3 days followed by oral mino, while 16 VAD-BSIs were treated with oral mino as the sole antimicrobial agent for systemic therapy. VAD management consisted of catheter removal (for tunneled catheters and PIC-lines, n = 7) or antibiotic locks with vanco (n = 15) or gentamicin (n = 2) administered at least 3 times a week for 14 days (for ports).

RESULTS

Overall, clearance of bacteremia (as assessed by negativity for the same CoNS of surveillance peripheral blood cultures drawn between day+ 3 and +30 after initiation of systemic therapy) was achieved in all but 1 patient (with port) who had persistent bacteremia at day +9. No complication such as suppurative thrombophlebitis, endocarditis, distant foci of infection or BSI-related death was observed in any patient during the 3-month period after initiation of treatment. Regarding the 17 port-BSI cases for which VAD conservative strategy was attempted, failure of 3-month VAD preservation was documented in 7/17 cases and 3-month recurrence of VAD-BSI was observed in 3/17 cases (with 1 patient with cellulitis). Treatment with mino was well tolerated except for a mild skin rash in one patient.

CONCLUSION

Further prospective studies are needed to evaluate efficacy and safety of this approach.

Sucralfate Prevents Pin Site Infections of External Fixators in Open Tibia Fractures

Pin site infections are the main complication of external fixators. The most common pathogens are Staphylococcus epidermidis and Staphylococcus aureus. The incidence of pin site infections ranges from 2% to 30%. Until now, no satisfactory prevention strategy exists. Therefore, we performed this study to assess the effect of a sucralfate gel 25% applied around the pins of external fixation systems in trauma patients with open tibia fractures. We prospectively studied two groups of patients with open tibia fractures treated with external fixators. In group A patients, pin site care was performed with the use of normal saline and plain dressings once a day. In group B patients, pin site care was performed with the use of sucralfate gel 25%. The incidence of pin site infections was 33.33% for patients of group A and 16.67% for patients of group B. Patients of group B showed significantly lower rate of pin site infections compared to patients of group A (p-value = 0.032). No patient experienced any complications related to the local application of the drug. Sucralfate significantly prevents pin site infections of external fixators in open tibia fractures. Therefore, it can be used as a preventive antimicrobial agent for pin site infections in patients with external fixators.

Successful antibiotic management of Staphylococcus epidermidis endophthalmitis after implantable collamer lens implantation

PURPOSE

We report a case of successful medical management of endophthalmitis post implantable collamer lens (ICL) culture-positive of Staphylococcus epidermidis.

OBSERVATIONS

A 18-year-old female presented with decreased visual acuity in the left eye 20 days after ICL implantation. A diagnosis of postoperative endophthalmitis was made based on examination and ultrasonography. A vitreous tap was taken, and intravitreal antibiotics (vancomycin 1 mg/0.1ml and ceftazidime 2 mg/0.1ml) were administered twice (every 72 h), and peribulbar injection of triamcinolone acetonide after four days of the second intravitreal injection. The vitreous culture was confirmed for Staphylococcus epidermidis. The endophthalmitis was resolved, and visual acuity improved from 6/20 to 12/20 on day 7 and 22/20 on day 38. This is the first successful medical resolution of Staphylococcus epidermidis endophthalmitis post ICL surgery without ICL explantation and vitrectomy in the V4c model.

CONCLUSIONS AND IMPORTANCE

In antibiotic therapy, the excellent compliance and close follow-up of this endophthalmitis patient enabled careful postoperative surveillance on the effect of antibiotic therapy, avoiding the removal of the ICL or the loss of the integrity of the eye. The risk of potential infectious endophthalmitis post-ICL surgery should be fully emphasized during preoperative counseling.

Freezing nitrogen ethanol composite reduces periprosthetic infection caused by Staphylococcus aureus contaminated metal implants: An animal study

BACKGROUND

Implant-associated infection remains a major complication of orthopedic surgery. The treatment of such infection is complicated by bacterial biofilm formation on the metal surfaces of implants. Biofilm surrounds and protects the bacteria against the organism's endogenous defense system and from external agents such as antibiotics and mechanical debridement. This study aims to evaluate whether freezing nitrogen ethanol composite (FNEC), the combination of liquid nitrogen and 95% ethanol in a 3 to 1 ratio, used frequently in bone tumor surgery, is capable of disinfecting Staphylococcus aureus contaminated implants.

METHODS

The femurs of six New Zealand white rabbits were implanted with S. aureus-contaminated screws, half of which were treated with FNEC before implantation. The femurs were harvested 14 days after implantation. Histological analysis and TUNEL assay were conducted. The autoclaved screw, contaminated screw, and FNEC-treated contaminated screw were investigated using scanning electron microscopy to evaluate the biofilm structure.

RESULTS

The FNEC-treated group had significantly lower relative C-reactive protein levels. An obvious periosteal reaction at the implant site was observed in all rabbits in the non-FNEC group but none was observed in the FNEC-treated group. The FNEC-treated group exhibited fewer empty lacunae, less inflammatory infiltration, and less bone necrosis. Immunohistochemical analysis showed no S. aureus in bone tissue from the FNEC-treated group. Scanning electron microscopy showed disruption of the biofilm on the contaminated screw treated with FNEC.

CONCLUSION

FNEC showed potential in disinfecting S.aureus-contaminated implants. Further investigation is warranted, such as the effect on the implant-cement-bone interface, for FNEC to be used clinically in treating implant-associated infection.

Increasing clinical impact and microbiological difficulties in diagnosing coagulase-negative staphylococci in infective endocarditis - a review starting from a series of cases

Coagulase-negative staphylococci (CoNS) are an emergent aetiology of infective endocarditis (IE) on native valves in previously healthy individuals, its presence is associated with prosthetic valves or with other cardiac implants. The identification of CoNS in cultures was customarily seen as contamination, but more recent epidemiological studies have revealed an increasing number of causative and virulent new CoNS species. Starting from two clinical cases of community-acquired CoNS IE on native valves, the review debates the difficulties in identifying CoNS as the causal pathogens, comprising differentiation of contamination from infection in IE, alongside the challenges raised by antibiotic resistance. Even if the risk of CoNS IE is more increased in subjects with prosthetic materials or other foreign devices and immunodeficiencies, native valve infections with these staphylococci are increasing and should be considered important pathogens in IE. Despite the lack of sensitive and specific tools to correctly differentiate contamination from infection in CoNS endocarditis, a comprehensive evaluation with clinical and paraclinical data accurately succeeds in establishing the diagnosis. The genetic profile of CoNS predisposes to antibiotic multi-resistance, making the treatment of IE challenging; the rapid identification of antibiotic susceptibility is essential to prescribe the appropriate therapy and improve outcomes.

Preoperative Colonization With Staphylococcus Aureus in THA Is Associated With Increased Length of Stay

BACKGROUND

Staphylococcus aureus is a common organism implicated in prosthetic joint infection after THA and TKA, prompting preoperative culturing and decolonization to reduce infection rates. It is unknown whether colonization is associated with other noninfectious outcomes of THA or TKA.

QUESTIONS/PURPOSES

(1) What is the association between preoperative S. aureus colonization (methicillin-sensitive S. aureus [MSSA] and methicillin-resistant S. aureus [MRSA]) and the noninfectious outcomes (discharge destination, length of stay, Hip/Knee Disability and Osteoarthritis Outcome Score [HOOS/KOOS] pain score, HOOS/KOOS physical function score, 90-day readmission, and 1-year reoperation) of THA and TKA? (2) What factors are associated with colonization with S. aureus ?

METHODS

Between July 2015 and March 2019, 8078 patients underwent primary THA in a single healthcare system, and 17% (1382) were excluded because they were not tested preoperatively for S. aureus nasal colonization, leaving 6696 patients in the THA cohort. Between June 2015 and March 2019, 9434 patients underwent primary TKA, and 12% (1123) were excluded because they were not tested for S. aureus colonization preoperatively, leaving 8311 patients in the TKA cohort. The goal of the institution's standardized care pathways is to test all THA and TKA patients preoperatively for S. aureus nasal colonization; the reason the excluded patients were not tested could not be determined. Per institutional protocols, all patients were given chlorhexidine gluconate skin wipes to use on the day before and the day of surgery, and patients with positive S. aureus cultures were instructed to use mupirocin nasal ointment twice daily for 3 to 5 days preoperatively. Adherence to these interventions was not tracked, and patients were not rescreened to test for S. aureus control. The minimum follow-up time for each outcome and the percentage of the cohort lost for each was: for discharge destination, until discharge (0 patients lost); for length of stay, until discharge (0.06% [4 of 6696] lost in the THA group and 0.01% [1 of 8311] lost in the TKA group); for HOOS/KOOS pain score, 1 year (26% [1734 of 6696] lost in the THA group and 24% [2000 of 8311] lost in the TKA group); for HOOS/KOOS physical function, 1 year (33% [2193 of 6696] lost in the THA group and 28% [2334 of 8311] lost in the TKA group); for 90-day readmission, 90 days (0.06% [4 of 6696] lost in the THA group and 0.01% [1 of 8311] lost in the TKA group); and for 1-year reoperation, 1 year (30% [1984 of 6696] lost in the THA group and 30% [2475 of 8311] lost in the TKA group). Logistic regression models were constructed to test for associations between MSSA or MRSA and nonhome discharge, length of stay greater than 1 day, improvement in the HOOS/KOOS pain subscale (≥ the minimum clinically important difference), HOOS/KOOS physical function short form (≥ minimum clinically important difference), 90-day readmission, and 1-year reoperation. We adjusted for patient-related and hospital-related factors, such as patient age and hospital site. Variable significance was assessed using the likelihood ratio test with a significance level of p < 0.05. To assess factors associated with S. aureus colonization, we constructed a logistic regression model with the same risk factors.

RESULTS

Among the THA cohort, after controlling for potentially confounding variables such as patient age, smoking status, and BMI, S. aureus colonization was associated with length of stay greater than 1 day (MSSA: odds ratio 1.32 [95% CI 1.08 to 1.60]; MRSA: OR 1.88 [95% CI 1.24 to 2.85]; variable p < 0.001 by likelihood ratio test) but not the other outcomes of THA. Male sex (OR 1.26 [95% CI 1.09 to 1.45]; p = 0.001) and BMI (OR 1.02 for a one-unit increase over median BMI [95% CI 1.01 to 1.03]; p = 0.003) were patient-related factors associated with S. aureus colonization, whereas factors associated with a lower odds were older age (OR 0.99 [95% CI 0.98 to 0.99]; p < 0.001) and Black race compared with White race (OR 0.64 [95% CI 0.50 to 0.82]; p < 0.001). Among the TKA cohort, S. aureus colonization was associated with 90-day readmission (MSSA: OR 1.00 [95% CI 0.99 to 1.01]; MRSA: OR 1.01 [95% CI 1.00 to 1.01]; variable p = 0.007 by likelihood ratio test). Male sex (OR 1.19 [95% CI 1.05 to 1.34]; p = 0.006) was associated with S. aureus colonization, whereas factors associated with a lower odds of colonization were older age (OR 0.99 [95% CI 0.98 to 0.99]; p < 0.001), Veterans RAND-12 mental component score (OR 0.99 [95% CI 0.99 to 1.00]; p = 0.027), Black race compared with White race (OR 0.70 [95% CI 0.57 to 0.85]; p < 0.001), and being a former smoker (OR 0.86 [95% CI 0.75 to 0.97]; p = 0.016) or current smoker (OR 0.70 [95% CI 0.55 to 0.90]; p = 0.005) compared with those who never smoked.

CONCLUSION

After controlling for the variables we explored, S. aureus colonization was associated with increased length of stay after THA and 90-day readmission after TKA, despite preoperative decolonization. Given that there is little causal biological link between colonization and these outcomes, the association is likely confounded but may be a proxy for undetermined social or biological factors, which may alert the surgeon to pay increased attention to outcomes in patients who test positive. Further study of the association of S. aureus colonization and increased length of stay after THA and readmission after TKA may be warranted to determine what the confounding variables are, which may be best accomplished using large cohorts or registry data.

LEVEL OF EVIDENCE

Level III, therapeutic study.

Very early infective endocarditis after transcatheter aortic valve replacement

BACKGROUND

Scarce data exist about early infective endocarditis (IE) after trans-catheter aortic valve replacement (TAVR).

OBJECTIVE

The objective was to evaluate the characteristics, management, and outcomes of very early (VE) IE (≤ 30 days) after TAVR.

METHODS

This multicenter study included a total of 579 patients from the Infectious Endocarditis after TAVR International Registry who had the diagnosis of definite IE following TAVR.

RESULTS

Ninety-one patients (15.7%) had VE-IE. Factors associated with VE-IE (vs. delayed IE (D-IE)) were female gender (p = 0.047), the use of self-expanding valves (p < 0.001), stroke (p = 0.019), and sepsis (p < 0.001) after TAVR. Staphylococcus aureus was the main pathogen among VE-IE patients (35.2% vs. 22.7% in the D-IE group, p = 0.012), and 31.2% of Staphylococcus aureus infections in the VE-IE group were methicillin-resistant (vs. 14.3% in the D-IE group, p = 0.001). The second-most common germ was enterococci (34.1% vs. 24.4% in D-IE cases, p = 0.05). VE-IE was associated with very high in-hospital (44%) and 1-year (54%) mortality rates. Acute renal failure following TAVR (p = 0.001) and the presence of a non-enterococci pathogen (p < 0.001) were associated with an increased risk of death.

CONCLUSION

A significant proportion of IE episodes following TAVR occurs within a few weeks following the procedure and are associated with dismal outcomes. Some baseline and TAVR procedural factors were associated with VE-IE, and Staphylococcus aureus and enterococci were the main causative pathogens. These results may help to select the more appropriate antibiotic prophylaxis in TAVR procedures and guide the initial antibiotic therapy in those cases with a clinical suspicion of IE. Very early infective endocarditis after trans-catheter aortic valve replacement. VE-IE indicates very early infective endocarditis (≤30 days post TAVR). D-IE indicates delayed infective endocarditis.

Comparative outcomes of combined corticosteroid and remdesivir therapy with corticosteroid monotherapy in ventilated COVID-19 patients

Remdesivir (RDV) reduces time to clinical improvement in hospitalized COVID -19 patients requiring supplemental oxygen. Dexamethasone improves survival in those requiring oxygen support. Data is lacking on the efficacy of combination therapy in patients on mechanical ventilation. We analyzed for comparative outcomes between Corticosteroid (CS) therapy with combined Corticosteroid and Remdesivir (CS-RDV) therapy. We conducted an observational cohort study of patients aged 18 to 90 with COVID-19 requiring ventilatory support using TriNetX (COVID-19 Research Network) between January 20, 2020, and February 9, 2021. We compared patients who received at least 48 hours of CS-RDV combination therapy to CS monotherapy. The primary outcome was 28-day all-cause mortality rates in propensity-matched (PSM) cohorts. Secondary outcomes were Length of Stay (LOS), Secondary Bacterial Infections (SBI), and MRSA (Methicillin-Resistant Staphylococcus aureus), and Pseudomonas infections. We used univariate and multivariate Cox proportional hazards models and stratified log-rank tests. Of 388 patients included, 91 (23.5%) received CS-RDV therapy, and 297 (76.5%) received CS monotherapy. After propensity score matching, with 74 patients in each cohort, all-cause mortality was 36.4% and 29.7% in the CS-RDV and CS therapy, respectively (P = 0.38). We used a Kaplan-Meier with a log-rank test on follow up period (P = 0.23), and a Hazards Ratio model (P = 0.26). SBI incidence was higher in the CS group (13.5% vs. 35.1%, P = 0.02) with a similar LOS (13.4 days vs. 13.4 days, P = 1.00) and similar incidence of MRSA/Pseudomonas infections (13.5% vs. 13.5%, P = 1.00) in both the groups. Therefore, CS-RDV therapy is non-inferior to CS therapy in reducing 28-day all-cause in-hospital mortality but associated with a significant decrease in the incidence of SBI in critically ill COVID-19 patients.

Surgical Treatment of Patients With Infective Endocarditis After Transcatheter Aortic Valve Implantation

BACKGROUND

The optimal treatment of patients developing infective endocarditis (IE) after transcatheter aortic valve implantation (TAVI) is uncertain.

OBJECTIVES

The goal of this study was to investigate the clinical characteristics and outcomes of patients with TAVI-IE treated with cardiac surgery and antibiotics (IE-CS) compared with patients treated with antibiotics alone (IE-AB).

METHODS

Crude and inverse probability of treatment weighting analyses were applied for the treatment effect of cardiac surgery vs medical therapy on 1-year all-cause mortality in patients with definite TAVI-IE. The study used data from the Infectious Endocarditis after TAVI International Registry.

RESULTS

Among 584 patients, 111 patients (19%) were treated with IE-CS and 473 patients (81%) with IE-AB. Compared with IE-AB, IE-CS was not associated with a lower in-hospital mortality (HR_unadj: 0.85; 95% CI: 0.58-1.25) and 1-year all-cause mortality (HR_unadj: 0.88; 95% CI: 0.64-1.22) in the crude cohort. After adjusting for selection and immortal time bias, IE-CS compared with IE-AB was also not associated with lower mortality rates for in-hospital mortality (HR_adj: 0.92; 95% CI: 0.80-1.05) and 1-year all-cause mortality (HR_adj: 0.95; 95% CI: 0.84-1.07). Results remained similar when patients with and without TAVI prosthesis involvement were analyzed separately. Predictors for in-hospital and 1-year all-cause mortality included logistic EuroSCORE I, Staphylococcus aureus, acute renal failure, persistent bacteremia, and septic shock.

CONCLUSIONS

In this registry, the majority of patients with TAVI-IE were treated with antibiotics alone. Cardiac surgery was not associated with an improved all-cause in-hospital or 1-year mortality. The high mortality of patients with TAVI-IE was strongly linked to patients' characteristics, pathogen, and IE-related complications.

Management and outcome of spinal implant-associated surgical site infections in patients with posterior instrumentation: analysis of 176 cases

PURPOSE

The management of implant-associated surgical site infections (SSI) in patients with posterior instrumentation is challenging. Evidence regarding the most appropriate treatment and the need for removal of implants is equivocal. We sought to evaluate the management and outcome of such patients at our institution.

METHODS

We searched our prospectively documented databases for eligible patients with posterior spinal instrumentation, excluding the cervical spine (January 2008-June 2018). Patient files were reviewed, demographic data and treatment details were recorded. Patient-reported outcome (PRO) was assessed with the Core Outcome Measures Index (COMI) preoperatively and postoperatively at 3 and 12 months.

RESULTS

A total of 170 patients underwent 210 revisions for 176 SSIs. Two-thirds presented within four weeks (105/176, 59.7%, median 22.5d, 7d-11.1y). The most common pathogens were Staphylococcus aureus (n = 79/210, 37.6%) and Staphylococcus epidermidis (n = 56/210, 26.7%). Debridement and implant retention was performed in 135/210 (64.3%) revisions and partial replacement in 62/210 (29.5%). In 28/176 SSI (15.9%), persistent infection required multiple revisions (≤ 4). Surgery was followed by intravenous and oral antimicrobial treatment (10-12w). In 139/176 SSIs (79%) with ≥ 1y follow-up, infection was cured in 115/139 (82.7%); relapse occurred in 9 (relapse rate: 5.1%). Two patients (1.4%) died. COMI decreased significantly (8.2 ± 1.5 vs. 4.8 ± 2.9, p < 0.0001) over 12 months. 72.7% of patients were (very) satisfied with their care.

CONCLUSION

Patients with SSI after posterior (thoraco-)lumbo(-sacral) instrumentation can be successfully treated in most cases with surgical and specific antibiotic treatment. An interdisciplinary approach is recommended. Loose implants should be replaced. In some cases, multiple revisions may be necessary. Patient outcomes were satisfactory.

Inflammation-Responsive Drug-Loaded Hydrogels with Sequential Hemostasis, Antibacterial, and Anti-Inflammatory Behavior for Chronically Infected Diabetic Wound Treatment

Stimuli-responsive hydrogels possess unique advantages in drug delivery due to their variable performance and status based on the external environment. In the present study, a dual-responsive (pH and reactive oxygen species (ROS)) hydrogel was prepared to realize drug release properties under inflammatory stimulation. By grafting 3-carboxy-phenylboronic acid to the gelatin molecular backbone and cross-linking with poly(vinyl alcohol), we successfully synthesized the inflammation-responsive drug-loaded hydrogels after encapsulation with vancomycin-conjugated silver nanoclusters (VAN-AgNCs) and pH-sensitive micelles loaded with nimesulide (NIM). This novel design not only retained the dynamic functions of hydrogels, such as injectability, self-healing, and remodeling, but also realized sequential and on-demand drug delivery at diabetic-infected wound sites. In this work, we found that the hydrogel exhibited excellent biocompatibility and hemostasis properties owing to the enhanced cell-adhesive property of the gelatin component. The significant antibacterial and anti-inflammatory effect of the hydrogel was demonstrated in an in vitro experiment. Moreover, in the in vivo experiment, the hydrogel was found to play a role in promoting infected wound healing through sequential hemostasis and antibacterial and anti-inflammatory processes. Collectively, this inflammation-responsive hydrogel design containing VAN-AgNCs and NIM-loaded micelles has great potential in the application of chronically infected diabetic wound treatment, as well as in other inflammatory diseases.

Platelet Deficiency Represents a Modifiable Risk Factor for Periprosthetic Joint Infection in a Preclinical Mouse Model

BACKGROUND

Well known for their hemostatic function, platelets are increasingly becoming recognized as important immunomodulators. The purpose of the present study was to assess the impact of platelet depletion on antimicrobial host defense in a mouse model of periprosthetic joint infection (PJI).

METHODS

Thrombocytopenia (TCP) was induced in C57BL/6 mice with use of a selective antibody against platelet CD41 (anti-CD41). Whole blood from pre-treated mice was incubated with Staphylococcus aureus to assess antimicrobial efficacy with use of bioluminescent imaging, quantitative histological staining, and colony forming unit (CFU) quantification. In parallel, untreated heterologous platelets were added to TCP blood to assess potential rescue of antimicrobial efficacy. In vivo, TCP and control mice underwent placement of a titanium implant in the femur inoculated with bioluminescent Xen36 S. aureus. Longitudinal bioluminescent imaging was performed postoperatively to quantify the evolution of bacterial burden, which was confirmed via assessment of S. aureus CFUs on the implant and in peri-implant tissue on postoperative day (POD) 28.

RESULTS

Anti-CD41 treatment resulted in significant dose-dependent reductions in platelet count. Ex vivo, platelet-depleted whole blood demonstrated significantly less bacterial reduction than control blood. These outcomes were reversed with the addition of untreated rescue platelets. In vivo, infection burden was significantly higher in TCP mice and was inversely correlated with preoperative platelet count (r2 = 0.63, p = 0.037). Likewise, CFU quantification on POD28 was associated with increased bacterial proliferation and severity of periprosthetic infection in TCP mice compared with controls.

CONCLUSIONS

Thrombocytopenia resulted in an increased bacterial burden both ex vivo and in vivo in a mouse model of PJI.

CLINICAL RELEVANCE

In orthopaedic patients, deficiencies in platelet quantity or function represent an easily modifiable risk factor for PJI.

Methicillin-Resistant Staphylococcus aureus Bloodstream Infections and Injection Drug Use, Tennessee, USA, 2015-2017

Rising injection drug use associated with these infections highlights the need for targeted interventions.

Recently, Tennessee, USA, has seen an increase in the use of commonly injected drugs, such as heroin and fentanyl. Injection drug use (IDU) practices can lead to life-threatening methicillin-resistant Staphylococcus aureus (MRSA) bloodstream infections (BSIs) and other serious diseases. We matched MRSA BSIs identified through the National Healthcare Safety Network to the Tennessee Hospital Discharge Data System to characterize the prevalence, demographics, and clinical characteristics associated with IDU in this disease population. Of the 7,646 MRSA BSIs identified during 2015–2017, we found that 1,839 (24.1%) were IDU-related. IDU-related BSIs increased by 118.9%; the greatest rise occurred among emergency department–onset infections (197.4%). IDU was more often associated with white, female, 18–49-year-old, and uninsured persons (p<0.001). We found >1 additional IDU-related diagnoses in 84.2% of IDU-related BSIs. Targeted harm reduction strategies for persons at high risk of IDU are necessary to reduce MRSA BSIs in acute care settings.

Single-stage revision of MRSA orthopedic device-related infection in sheep with an antibiotic-loaded hydrogel

Local antimicrobial therapy is an integral aspect of treating orthopedic device-related infection (ODRI), which is conventionally administered via polymethyl-methacrylate (PMMA) bone cement. PMMA, however, is limited by a suboptimal antibiotic release profile and a lack of biodegradability. In this study, we compare the efficacy of PMMA versus an antibiotic-loaded hydrogel in a single-stage revision for chronic methicillin-resistant Staphylococcus aureus (MRSA) ODRI in sheep. Antibiofilm activity of the antibiotic combination (gentamicin and vancomycin) was determined in vitro. Swiss alpine sheep underwent a single-stage revision of a tibial intramedullary nail with MRSA infection. Local gentamicin and vancomycin therapy was delivered via hydrogel or PMMA (n = 5 per group), in conjunction with systemic antibiotic therapy. In vivo observations included: local antibiotic tissue concentration, renal and liver function tests, and quantitative microbiology on tissues and hardware post-mortem. There was a nonsignificant reduction in biofilm with an increasing antibiotic concentration in vitro (p = 0.12), confirming the antibiotic tolerance of the MRSA biofilm. In the in vivo study, four out of five sheep from each treatment group were culture-negative. Antibiotic delivery via hydrogel resulted in 10-100 times greater local concentrations for the first 2-3 days compared with PMMA and were comparable thereafter. Systemic concentrations of gentamicin were minimal or undetectable in both groups, while renal and liver function tests were within normal limits. This study shows that a single-stage revision with hydrogel or PMMA is equally effective, although the hydrogel offers certain practical benefits over PMMA, which make it an attractive proposition for clinical use.

Locally delivered adjuvant biofilm-penetrating antibiotics rescue impaired endochondral fracture healing caused by MRSA infection

Infection is a devastating complication following an open fracture. We investigated whether local rifampin-loaded hydrogel can combat infection and improve healing in a murine model of methicillin-resistant Staphylococcus aureus (MRSA) osteomyelitis. A transverse fracture was made at the tibia midshaft of C57BL/6J mice aged 10-12 weeks and stabilized with an intramedullary pin. A total of 1 × 106 colony-forming units (CFU) of MRSA was inoculated. A collagen-based hydrogel containing low-dose (60 μg) and high-dose (300 μg) rifampin was applied before closure. Postoperative treatment response was assessed through bacterial CFU counts from tissue and hardware, tibial radiographs and microcomputed tomography (μCT), immunohistochemistry, and histological analyses. All untreated MRSA-infected fractures progressed to nonunion by 28 days with profuse MRSA colonization. Infected fractures demonstrated decreased soft callus formation on safranin O stain compared to controls. Areas of dense interleukin-1β stain were associated with poor callus formation. High-dose rifampin hydrogels reduced the average MRSA load in tissue (p < 0.0001) and implants (p = 0.041). Low-dose rifampin hydrogels reduced tissue bacterial load by 50% (p = 0.021). Among sterile models, 88% achieved union compared to 0% of those infected. Mean radiographic union scale in tibia scores improved from 6 to 8.7 with high-dose rifampin hydrogel (p = 0.024) and to 10 with combination local/systemic rifampin therapy (p < 0.0001). μCT demonstrated reactive bone formation in MRSA infection. Histology demonstrated restored fracture healing with bacterial elimination. Rifampin-loaded hydrogels suppressed osteomyelitis, prevented implant colonization, and improved healing. Systemic rifampin was more effective at eliminating infection and improving fracture healing. Further investigation into rifampin-loaded hydrogels is required to correlate these findings with clinical efficacy.

Colonization with multidrug-resistant organisms is associated with in increased mortality in liver transplant candidates

Objectives

Rising prevalence of multidrug-resistant organisms (MDRO) is a major health problem in patients with liver cirrhosis. The impact of MDRO colonization in liver transplantation (LT) candidates and recipients on mortality has not been determined in detail.

Methods

Patients consecutively evaluated and listed for LT in a tertiary German liver transplant center from 2008 to 2018 underwent screening for MDRO colonization including methicillin-resistant Staphylococcus aureus (MRSA), multidrug-resistant gram-negative bacteria (MDRGN), and vancomycin-resistant enterococci (VRE). MDRO colonization and infection status were obtained at LT evaluation, planned and unplanned hospitalization, three months upon graft allocation, or at last follow-up on the waiting list.

Results

In total, 351 patients were listed for LT, of whom 164 (47%) underwent LT after a median of 249 (range 0–1662) days. Incidence of MDRO colonization increased during waiting time for LT, and MRDO colonization was associated with increased mortality on the waiting list (HR = 2.57, p<0.0001. One patients was colonized with a carbapenem-resistant strain at listing, 9 patients acquired carbapenem-resistant gram-negative bacteria (CRGN) on the waiting list, and 4 more after LT. In total, 10 of these 14 patients died.

Conclusions

Colonization with MDRO is associated with increased mortality on the waiting list, but not in short-term follow-up after LT. Moreover, colonization with CRGN seems associated with high mortality in liver transplant candidates and recipients.

Infective endocarditis as a complication of longstanding ventriculoatrial (VA) shunt: the importance of suspicion and early investigation in patients with VA shunt and pyrexia of unknown origin

Ventriculoatrial (VA) shunts are a method of cerebrospinal fluid diversion, which nowadays are infrequently seen in medical practice. Infective endocarditis (IE) can occur as rare complications of VA shunts, through the introduction of a foreign body close to the tricuspid valve. We report a case of infective endocarditis, that is, in a patient with VA shunt for congenital hydrocephalus. We present the case to highlight the importance of early investigation for IE in patients with fever of unknown origin and shunt in situ, as rapid deterioration can occur and be fatal. We also discuss past experience reported in the literature on the role of cardiothoracic intervention. Prompt diagnosis and early cardiothoracic referral for surgery are crucial, there may only be a narrow window of opportunity for intervention before patients develop fulminant sepsis.

Essential Oils Biofilm Modulation Activity, Chemical and Machine Learning Analysis. Application on Staphylococcus aureus Isolates from Cystic Fibrosis Patients

Bacterial biofilm plays a pivotal role in chronic Staphylococcus aureus (S. aureus) infection and its inhibition may represent an important strategy to develop novel therapeutic agents. The scientific community is continuously searching for natural and “green alternatives” to chemotherapeutic drugs, including essential oils (EOs), assuming the latter not able to select resistant strains, likely due to their multicomponent nature and, hence, multitarget action. Here it is reported the biofilm production modulation exerted by 61 EOs, also investigated for their antibacterial activity on S. aureus strains, including reference and cystic fibrosis patients’ isolated strains. The EOs biofilm modulation was assessed by Christensen method on five S. aureus strains. Chemical composition, investigated by GC/MS analysis, of the tested EOs allowed a correlation between biofilm modulation potency and putative active components by means of machine learning algorithms application. Some EOs inhibited biofilm growth at 1.00% concentration, although lower concentrations revealed different biological profile. Experimental data led to select antibiofilm EOs based on their ability to inhibit S. aureus biofilm growth, which were characterized for their ability to alter the biofilm organization by means of SEM studies.

In Vitro Evaluation of Gentamicin or Vancomycin Containing Bone Graft Substitute in the Prevention of Orthopedic Implant-Related Infections

Antibiotic-loaded bone graft substitutes are attractive clinical options and have been used for years either for prophylaxis or therapy for periprosthetic and fracture-related infections. Calcium sulfate and hydroxyapatite can be combined in an injectable and moldable bone graft substitute that provides dead space management with local release of high concentrations of antibiotics in a one-stage approach. With the aim to test preventive strategies against bone infections, a commercial hydroxyapatite/calcium sulfate bone graft substitute containing either gentamicin or vancomycin was tested against Staphylococcus aureus, Staphylococcus epidermidis and Pseudomonas aeruginosa, harboring different resistance determinants. The prevention of bacterial colonization and biofilm development by selected microorganisms was investigated along with the capability of the eluted antibiotics to select for antibiotic resistance. The addition of antibiotics drastically affected the ability of the selected strains to adhere to the tested compound. Furthermore, both the antibiotics eluted by the bone graft substitutes were able to negatively impair the biofilm maturation of all the staphylococcal strains. As expected, P. aeruginosa was significantly affected only by the gentamicin containing bone graft substitutes. Finally, the prolonged exposure to antibiotic-containing sulfate/hydroxyapatite discs did not lead to any stable or transient adaptations in either of the tested bacterial strains. No signs of the development of antibiotic resistance were found, which confirms the safety of this strategy for the prevention of infection in orthopedic surgery.

Staphylococcus aureus and Hyper-IgE Syndrome

Hyper-immunoglobulin E syndrome (HIES) is a primary immunodeficiency disease characterized by recurrent Staphylococcus aureus (S. aureus) infections, eczema, skeletal abnormalities and high titers of serum immunoglobulin E. Although the genetic basis of HIES was not known for almost a half century, HIES most frequently exhibits autosomal dominant trait that is transmitted with variable expressivity. Careful genetic studies in recent years identified dominant-negative mutations in human signal transducer and activator of transcription 3 (STAT3) gene as the cause of sporadic and dominant forms of HIES. The STAT3 mutations were localized to DNA-binding, SRC homology 2 (SH2) and transactivating domains and disrupted T helper 17 (T_H17) cell differentiation and downstream expression of T_H17 cytokines IL-17 and IL-22. Deficiency of IL-17 and IL-22 in turn is responsible for suboptimal expression of anti-staphylococcal host factors, such as neutrophil-recruiting chemokines and antimicrobial peptides, by human keratinocytes and bronchial epithelial cells. T_H17 cytokines deficiency thereby explains the recurrent staphylococcal lung and skin infections of HIES patients.

Carbapenems drive the collateral resistance to ceftaroline in cystic fibrosis patients with MRSA

Chronic airways infection with methicillin-resistant Staphylococcus aureus (MRSA) is associated with worse respiratory disease cystic fibrosis (CF) patients. Ceftaroline is a cephalosporin that inhibits the penicillin-binding protein (PBP2a) uniquely produced by MRSA. We analyzed 335 S. aureus isolates from CF sputum samples collected at three US centers between 2015-2018. Molecular relationships demonstrated that high-level resistance of preceding isolates to carbapenems were associated with subsequent isolation of ceftaroline resistant CF MRSA. In vitro evolution experiments showed that pre-exposure of CF MRSA to meropenem with further selection with ceftaroline implied mutations in mecA and additional mutations in pbp1 and pbp2, targets of carbapenems; no effects were achieved by other β-lactams. An in vivo pneumonia mouse model showed the potential therapeutic efficacy of ceftaroline/meropenem combination against ceftaroline-resistant CF MRSA infections. Thus, the present findings highlight risk factors and potential therapeutic strategies offering an opportunity to both prevent and address antibiotic resistance in this patient population.

Staphylococcus aureus Exotoxins and Their Detection in the Dairy Industry and Mastitis

Staphylococcus aureus constitutes a major food-borne pathogen, as well as one of the main causative agents of mastitis in dairy ruminants. This pathogen can produce a variety of extracellular toxins; these include the shock syndrome toxin 1 (TSST-1), exfoliative toxins, staphylococcal enterotoxins (SE), hemolysins, and leukocidins. S. aureus expresses many virulence proteins, involved in evading the host defenses, hence facilitating microbial colonization of the mammary glands of the animals. In addition, S. aureus exotoxins play a role in the development of both skin infections and mastitis. Indeed, if these toxins remain in dairy products for human consumption, they can cause staphylococcal food poisoning (SFP) outbreaks. As a result, there is a need for procedures to identify the presence of exotoxins in human food, and the methods used must be fast, sensitive, reliable, and accurate. It is also essential to determine the best medical therapy for human patients suffering from S. aureus infections, as well as establishing the relevant veterinary treatment for infected ruminants, to avoid economic losses in the dairy industry. This review summarizes the role of S. aureus toxins in the development of mastitis in ruminants, their negative effects in the food and dairy industries, and the different methods used for the identification of these toxins in food destined for human consumption.

Neonatal sepsis at Mulago national referral hospital in Uganda: Etiology, antimicrobial resistance, associated factors and case fatality risk

Background

Sepsis is the third most common cause of death among neonates, with about 225,000 newborns dying every year globally. Data concerning the microbial etiology of neonatal sepsis and antimicrobial resistance profiles of its causative agents are necessary to inform targeted and effective treatment and prevention strategies.

Objective

To determine the proportion of newborns with symptoms and signs of sepsis who had a positive blood culture, its bacterial etiology, the antimicrobial resistance patterns as well as the factors associated with culture-positivity and case fatality at Mulago national referral hospital in Uganda.

Methods

We conducted a cross-sectional study among 359 neonates with symptoms and signs of sepsis who presented to the pediatric emergency care unit of Mulago national referral hospital from mid-January to end of December 2018. We performed blood culture and antimicrobial susceptibility testing, and conducted polymerase chain reaction to identify methicillin-resistant Staphylococcus aureus (MRSA) isolates. We used multivariable logistic regression to estimate the association between potential risk factors and culture-positive neonatal sepsis.

Findings

Of the 359 neonates recruited, 46 (12.8%; 95% CI 9.5%, 16.7%) had a positive blood culture. The predominant isolated bacteria were Staphylococcus aureus in 29 (63.0%), Escherichia coli in seven (15.2%), and Klebsiella pneumoniae in five (10.9%). Of the 46 pathogens, 73.9% were resistant to ampicillin, 23.9% to gentamicin and 8.7% to ceftriaxone. We isolated MRSA from the blood specimens of 19 (5.3%) of the 359 neonates, while 3 (0.8%) grew extended spectrum beta lactamase producers. The case fatality risk among neonates with neonatal sepsis was 9.5% (95% CI: 6.6%, 13.0%). Cesarean section delivery was strongly associated with culture-positive sepsis (adjusted odds ratio 3.45, 95% CI: 1.2, 10.1).

Conclusion

One in eight neonates with clinical signs of sepsis grew a likely causative bacterial pathogen. S. aureus was the main pathogen isolated and a third of these isolates were MRSA. A significant proportion of the isolated bacterial pathogens were resistant to the first and second line antibiotics used for the treatment of neonatal sepsis. There is need to revisit the current treatment guidelines for neonatal sepsis.

Staphylococcus aureus Bacteremia: Contemporary Management

Staphylococcus aureus bacteremia (SAB) is a serious cause of bloodstream infection associated with significant morbidity and mortality. Complications include deep-seated foci of infection including infective endocarditis, device-associated infection, osteoarticular metastases, pleuropulmonary involvement, and recurrent infection. With the 30-day all-cause mortality being around 20%, a collaborative effort of early Infectious Diseases (ID) consultation and Antimicrobial Stewardship Program (ASP) involvement will show improved SAB outcomes and therapy optimization.1.

Deep surgical site infection after posterior instrumented fusion for rheumatoid upper cervical subluxation treated with antibiotic-loaded bone cement: Three case reports

INTRODUCTION

Patients with rheumatoid arthritis (RA) tend to be immunosuppressed due to RA itself and the therapeutic drugs administered. The management of surgical site infection (SSI) following upper cervical spinal instrumented fusion in RA patients is challenging; however, literature on the treatment for such conditions is scarce. We report 3 consecutive patients with RA, who developed deep SSI following upper cervical posterior fusion and were treated using antibiotic-loaded bone cement (ALBC).

PATIENT CONCERNS

All 3 patients reported in the current study experienced compression myelopathy with upper cervical spinal deformity and received prednisolone and methotrexate for controlling RA preoperatively. The patient in Case 1 underwent C1-2 posterior fusion and developed deep SSI due to methicillin-sensitive Staphylococcus aureus at 3 months postoperatively; the patient in Case 2 underwent occipito-C2 posterior fusion and developed deep SSI due to methicillin-sensitive Staphylococcus aureus at 2 weeks postoperatively; and the patient in Case 3 underwent occipito-C2 posterior instrumented fusion and laminoplasty at C3-7, and developed deep SSI due to methicillin-resistant coagulase negative staphylococci at 3 weeks postoperatively.

DIAGNOSIS

All patients developed deep staphylococcal SSI in the postoperative period.

INTERVENTIONS

All 3 patients were treated using ALBC placed on and around the instrumentation to cover them and occupy the dead space after radical open debridement.

OUTCOMES

The deep infection was resolved uneventfully after the single surgical intervention retaining spinal instrumentation. Good clinical outcomes of the initial surgery were maintained until the final follow-up without recurrence of SSI in all 3 cases.

CONCLUSION

ALBC embedding spinal instrumentation procedure can be a viable treatment for curing SSI in complex cases, such as patients with RA who undergo high cervical fusion surgeries without implant removal.

TLR2 and caspase-1 signaling are critical for bacterial containment but not clearance during craniotomy-associated biofilm infection

BACKGROUND

A craniotomy is required to access the brain for tumor resection or epilepsy treatment, and despite precautionary measures, infectious complications occur at a frequency of 1-3%. Approximately half of craniotomy infections are caused by Staphylococcus aureus (S. aureus) that forms a biofilm on the bone flap, which is recalcitrant to antibiotics. Our prior work in a mouse model of S. aureus craniotomy infection revealed a critical role for myeloid differentiation factor 88 (MyD88) in bacterial containment and pro-inflammatory mediator production. Since numerous receptors utilize MyD88 as a signaling adaptor, the current study examined the importance of Toll-like receptor 2 (TLR2) and TLR9 based on their ability sense S. aureus ligands, namely lipoproteins and CpG DNA motifs, respectively. We also examined the role of caspase-1 based on its known association with TLR signaling to promote IL-1β release.

METHODS

A mouse model of craniotomy-associated biofilm infection was used to investigate the role of TLR2, TLR9, and caspase-1 in disease progression. Wild type (WT), TLR2 knockout (KO), TLR9 KO, and caspase-1 KO mice were examined at various intervals post-infection to quantify bacterial burden, leukocyte recruitment, and inflammatory mediator production in the galea, brain, and bone flap. In addition, the role of TLR2-dependent signaling during microglial/macrophage crosstalk with myeloid-derived suppressor cells (MDSCs) was examined.

RESULTS

TLR2, but not TLR9, was important for preventing S. aureus outgrowth during craniotomy infection, as revealed by the elevated bacterial burden in the brain, galea, and bone flap of TLR2 KO mice concomitant with global reductions in pro-inflammatory mediator production compared to WT animals. Co-culture of MDSCs with microglia or macrophages, to model interactions in the brain vs. galea, respectively, also revealed a critical role for TLR2 in triggering pro-inflammatory mediator production. Similar to TLR2, caspase-1 KO animals also displayed increased S. aureus titers coincident with reduced pro-inflammatory mediator release, suggestive of pathway cooperativity. Treatment of caspase-1 KO mice with IL-1β microparticles significantly reduced S. aureus burden in the brain and galea compared to empty microparticles, confirming the critical role of IL-1β in limiting S. aureus outgrowth during craniotomy infection.

CONCLUSIONS

These results demonstrate the existence of an initial anti-bacterial response that depends on both TLR2 and caspase-1 in controlling S. aureus growth; however, neither pathway is effective at clearing infection in the WT setting, since craniotomy infection persists when both molecules are present.

Multidrug-Resistant Staphylococcus epidermidis Ventriculostomy-Related Infection Successfully Treated by Intravenous Ceftaroline after Failure of Daptomycin Treatment

BACKGROUND

Ventriculostomy-related infection with multidrug-negative strains are challenging to treat. We report the use of new antibiotics in such a case.

CASE DESCRIPTION

We report the case of a neurosurgical intensive care unit patient who developed ventriculostomy-related infection with a multidrug-resistant Staphylococcus epidermidis. Vancomycin, recommended in such cases, was not used due to high minimal inhibitory concentrations and concerns for lack of pharmacokinetic/pharmacodynamic target attainment. Daptomycin and ceftaroline remained the only treatment options. Daptomycin was shown microbiologically ineffective after 10 treatment days, with undetectable cerebrospinal fluid (CSF) concentration. Ceftaroline, a novel beta-lactam agent to which the strain showed susceptibility, was thus used. Serum and CSF samples were assessed for antibiotic concentrations. Our results show that CSF bacterial clearance was obtained after 6 days of such treatment. Serum and CSF samplings showed low penetration ratios (2.6%-4.8%), probably due to mild inflammatory CSF profile, with CSF concentration at minimal inhibitory concentration level.

CONCLUSIONS

We observed than even in the case of mild meningeal inflammation, ceftaroline penetration in CSF, although moderate, enabled efficient bacterial clearance and clinical efficacy, in adjunction to correct ventriculoperitoneal shunt management.

Disrupted tongue microbiota and detection of nonindigenous bacteria on the day of allogeneic hematopoietic stem cell transplantation

Disruption of the intestinal microbiota caused by intensive chemotherapy, irradiation and antibiotics can result in development of severe gut graft-versus-host disease and infectious complications, leading to poorer outcomes among allogeneic hematopoietic stem cell transplantation (allo-HSCT) recipients. Although the oral cavity is also densely colonized by indigenous microorganisms, the bacterial composition in allo-HSCT recipients remains unclear. We determined the tongue microbiota composition of 45 patients with hematological disorders on the day of transplantation and compared them to 164 community-dwelling adults. The V1–V2 regions of the 16S rRNA gene sequences demonstrated that the allo-HSCT recipients had less diverse and distinct microbiota from that of community-dwelling adults. The full-length 16S rRNA gene sequences identified 146 bacterial taxa in the microbiota of allo-HSCT recipients, of which 34 bacterial taxa did not correspond to bacteria primarily inhabiting the oral cavity deposited in the expanded Human Oral Microbiome Database. Notably, the detection of Staphylococcus haemolyticus and/or Ralstonia pickettii was significantly associated with a higher risk of mortality during the follow-up period. These results demonstrate that the oral cavity of allo-HSCT recipients is colonized by a disrupted microbiota on the day of transplantation and suggest that detection of specific nonindigenous taxa could be a predictor of transplant outcome.

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) recipients are subjected to intensive chemotherapy, irradiation and antibiotics which could affect the intestinal as well as oral microbiota. We employed full-length 16S rRNA gene sequencing analysis with high taxonomic resolution using a third-generation sequencer, PacBio Sequel, and determined the bacterial composition of the tongue microbiota of allo-HSCT recipients after conditioning regimens. This comprehensive molecular approach identified 34 taxa uncommon in the oral cavity, which constituted 0–99.4% (median, 0.27%) of each tongue microbiota. Of them, Staphylococcus haemolyticus and Ralstonia pickettii were frequently found in allo-HSCT recipients, and their detection was significantly associated with a higher risk of mortality during the follow-up period. These results suggest that careful attention should be given to the bacterial composition of the disrupted oral microbiota in allo-HSCT recipients.

Infective Endocarditis of a Left Ventricular Myxoma in a Heroin User

Infected cardiac myxomas are rare and can have disastrous sequelae; urgent surgical resection is typically indicated. We report the case of a 43-year-old user of intravenous heroin who presented with weakness and dyspnea. He was diagnosed with infective endocarditis of a myxoma attached to the left ventricular lateral wall. The patient underwent successful surgical resection of the myxoma and then completed 4 weeks of antibiotic therapy. In addition to discussing this patient's case, we briefly review the relevant medical literature, in which we found only 4 previous reports of left ventricular myxoma associated with infective endocarditis.

What is the best management option for non-significant residual shunt after device closure of perimembranous ventricular septal defect: A case report based on the lessons from post-procedure endocarditis

RATIONALE

Non-significant residual shunt is a relatively common complication after device closure of perimembranous ventricular septal defects (Pm-VSD). Lifelong antibiotic prophylaxis has been recommended in guidelines to avoid infectious endocarditis (IE) if residual shunt remains. Clinicians, however, rarely follow it in their practice and regular follow-up was the most common option since post-procedure IE after transcatheter closure of PmVSD is rarely reported. We firstly described a case of IE after transcatheter closure of PmVSD with modified symmetrical double-disk device with a residual shunt, highlighting the need for reassessing the prognostic implications of post-procedure non-significant residual shunt and the most appropriate treatment strategy.

PATIENT CONCERNS

A 3-year old female received transcatheter closure of PmVSD sized 5.0 mm on left ventricular angiography with an 8-mm modified symmetric double-disk occluder (SHAMA) owing to a history of recurrent lower respiratory tract infections. Post-procedure echocardiography documented a non-significant residual shunt, but no additional interventions were performed. Two months post procedure, the child was re-admitted into our department with a complaint of persistent fever up to 41°C for 11 days and nonresponse to 1-week course of amoxicillin.

DIAGNOSES

The diagnosis of post procedure IE was established since a vegetation (13 × 9 mm) was found to be attached to the tricuspid valve and the occluder, and Staphylococcus aureus was isolated from all three-blood cultures.

INTERVENTIONS

After 6 weeks of vancomycin treatment, the vegetation disappeared with no sign of valvular dysfunction. Three weeks after discharge, a second device was implanted to abolish persistent residual flow.

OUTCOMES

Unfortunately, the child was ultimately transferred to surgical department due to severe hemolysis after the second device implantation. The occluders were removed and the VSD was closed with a pericardial patch. Tricuspid valvuloplasty was also performed and the following course was uneventful.

LESSONS

For non-significant residual shunt after device closure of PmVSD, implantation of a second device or surgical repair may be a better and more satisfactory alternative compared with lifelong antibiotic prophylaxis or no interventions, since associated IE can indeed occur despite its rarity and the risk of antibiotic-associated adverse events may outweigh the benefits.

[Linezolid-induced lactic acidosis - a brief overview with a case report]

Lactic acidosis is a rare but serious adverse event linked to treatment with linezolid, an oxazolidinone antibiotic. Presented is a case of a 67-year-old man treated for 26 days with linezolid for staphylococcal osteomyelitis of the right foot with subsequent sepsis. During the course of treatment, severe lactic acidosis developed, requiring hospitalization in an intensive care unit. The likely mechanism of this potentially life-threatening complication is discussed.

"A contemporary description of staphylococcus aureus prosthetic valve endocarditis. Differences according to the time elapsed from surgery"

Staphylococcus aureus prosthetic valve endocarditis (SAPVE) has a poor prognosis. There are no large series that accurately describe this entity.This is a retrospective observational study on a prospective cohort from 3 Spanish reference hospitals for cardiac surgery, including 78 definitive episodes of left SAPVE between 1996 and 2016.Fifty percent had a Charlson Index score >5; 53% were health care-related. Twenty percent did not present fever. Complications at diagnosis included: severe heart failure (HF, 29%), septic shock (SS, 17.9%), central nervous system abnormalities (19%), septic metastasis (4%). Hemorrhagic stroke was not higher in anticoagulated patients. Twenty-seven percent were methicilin-resistant SA (MRSA). Fifteen of 31 had positive valve culture; it was related to surgery within first 24 hours. At diagnosis, 69% had vegetation (>10 mm in 75%), 21.8% perianular extension, and 20% prosthetic dehiscence. Forty-eight percent had persistent bacteremia, related to nonsurgical treatment. Perianular extension progressed in 18%. Surgery was performed in 35 episodes (12 with stroke). Eleven uncomplicated episodes were managed with medical therapy, 8 survived. In-hospital mortality was 55%, higher in episodes with hemorrhagic stroke (77.8% vs 52.2%, odds ratio 3.2 [0.62-16.55]). Early SAPVE was nosocomial (92%), presented as severe HF (54%), patients were diagnosed and operated on early, 38% died. In intermediate SAPVE (9 weeks-1 year) diagnosis was delayed (24%), patients presented with constitutional syndrome (18%), renal failure (41%), and underwent surgery >72 hours after indication; 53% died. Late SAPVE (>1 year) was related with health care, diagnosis delay, and 60% of deceases.Left SAPVE frequently affected patients with comorbidity and health care contact. Complications at diagnosis and absence of fever were frequent. Presence of MRSA was high. Positive valve culture was related to early surgery. Paravalvular extension was frequent; vegetations were large, but its absence at diagnosis was common. Some uncomplicated SAPVE episodes were safety treated with medical therapy. Surgery was feasible in patients with stroke. Mortality was high. There were differences in some clinical characteristics and in evolution according to the time elapsed from valve replacement. Prognosis was better in early SAPVE.

Surgical site infection following elective orthopaedic surgeries in geriatric patients: Incidence and associated risk factors

The purposes of this study were to investigate the incidence of surgical site infection (SSI) following geriatric elective orthopaedic surgeries and identify the associated risk factors This was a retrospective two-institution study. Between January 2014 and September 2017, patients aged 60 years or older undergoing elective orthopaedic surgeries were included for data collection and analysis. SSI was identified through the review of patients' medical records for the index surgery and through the readmission diagnosis of SSI. Patients' demographics, characteristics of disease, surgery-related variables, and laboratory examination indexes were inquired and documented. Univariate and multivariate logistic analyses were performed to determine independent risk factors for SSI. There were 4818 patients undergoing elective orthopaedic surgeries, and within postoperative 1 year, 74 patients were identified to develop SSIs; therefore, the overall incidence of SSI was 3.64%, with 0.4% for deep and 1.1% for superficial infection. Staphylococcus aureus (25/47, 53.2%) and coagulase-negative staphylococci (11/47, 23.4%) were the most common causative pathogens; half of S. aureus SSIs were caused by Methicillin-resistant Staphylococcus aureus (MRSA) (12/25, 48.0%). Five risk factors were identified to be independently associated with SSI, including diabetes mellitus (odds ratio [OR], 3.7; 95% confidence interval [95% CI], 1.7-5.6), morbid obesity (OR, 2.6; 95% CI, 1.3-3.9), tobacco smoking (OR, 4.2; 95% CI, 2.1-6.4), surgical duration>75th percentile (OR, 1.9; 95% CI, 1.0-2.9), and ALB < 35.0 g/L (OR, 2.3; 95% CI, 1.3-3.4). We recommend the optimisation of modifiable risk factors such as morbid obesity, tobacco smoking, and lower serum albumin level prior to surgeries to reduce the risk of SSI.

Lysostaphin and BMP-2 co-delivery reduces S. aureus infection and regenerates critical-sized segmental bone defects

Staphylococcus aureus is the most common pathogen associated with bacterial infections in orthopedic procedures. Infections often lead to implant failure and subsequent removal, motivating the development of bifunctional materials that both promote repair and prevent failure due to infection. Lysostaphin is an anti-staphylococcal enzyme resulting in bacterial lysis and biofilm reduction. Lysostaphin use is limited by the lack of effective delivery methods to provide sustained, high doses of enzyme to infection sites. We engineered a BMP-2-loaded lysostaphin-delivering hydrogel that simultaneously prevents S. aureus infection and repairs nonhealing segmental bone defects in the murine radius. Lysostaphin-delivering hydrogels eradicated S. aureus infection and resulted in mechanically competent bone. Cytokine and immune cell profiling demonstrated that lysostaphin-delivering hydrogels restored the local inflammatory environment to that of a sterile injury. These results show that BMP-2-loaded lysostaphin-delivering hydrogel therapy effectively eliminates S. aureus infection while simultaneously regenerating functional bone resulting in defect healing.

The Pros and Cons of Cystic Fibrosis (CF) Patient Use of Herbal Supplements Containing Pulmonaria officinalis L. Extract: the Evidence from an In Vitro Study on Staphylococcus aureus CF Clinical Isolates

The justification for the use of herbal supplements with Pulmonaria officinalis L. extract (POE) in the case of staphylococcal lung colonization/infections characteristic for cystic fibrosis (CF), was examined in vitro. The impact of POE phenolic-rich fraction on the virulence attributes of CF-associated Staphylococcus aureus (S. aureus) clinical strains has been assessed, including pathogen adhesion, biofilm formation on native and protein-conditioned surfaces (mucin, elastin), mature biofilm eradication, staphylococcal protein A expression, α-toxin release, and S. a. adhesion to A549 cells. Cytotoxicity of the extract to lung epithelial cells was also investigated. It was found that POE has bacteriostatic effects at MIC 1⁻2 mg/mL, recognized as of limited efficacy, but at MIC/subMICs it targeted virulence not viability. It usually decreased S. aureus adhesion and less frequently inhibited biofilm formation on native and protein-conditioned surfaces. Observed effect seems to be related to significant reduction by POE of sortase A activity. However, in some cases POE favored the creation of biofilm by staphylococci and S. aureus adhesion to the lung epithelium was not limited. On the other side POE caused significant decrease of S. a. α-toxin synthesis and slightly weakened the expression of SpA. When used at supraMICs POE eradicated mature biofilm, but in some cases with unsatisfying outcomes. Promisingly, POE has been recognized as a safe product, with no cytotoxicity up to 4 mg/mL. These results reflect the positive, negative or neutral anti-staphylococcal properties of POE. It seems that POE may be beneficial as a prophylactic, but not as a therapeutic or supportive agent in the area of CF-integrative medicine. However, introduction the official recommendations needs further in vivo studies.

Would hemodialysis patients benefit from a Staphylococcus aureus vaccine?

Staphylococcus aureus bloodstream infection can have potentially catastrophic consequences for patients on hemodialysis. Consequently, an effective vaccine to prevent S aureus infection would have a significant influence on morbidity and mortality in this group. To date, however, efforts to develop a vaccine have been unsuccessful. Previous antibody-inducing vaccine candidates did not prevent or attenuate S aureus infection in clinical trials. Recent advances have helped to elucidate the role of specific T-cell subsets, notably T-helper cell 1 and T-helper cell 17, in the immune response to S aureus. These cells are essential for coordinating an effective phagocytic response via cytokine production, indirectly leading to destruction of the organism. It is now widely accepted that next-generation S aureus vaccines must also induce effective T-cell-mediated immunity. However, there remains a gap in our knowledge: how will an S aureus vaccine drive these responses in those patients most at risk? Given that patients on hemodialysis are an immunocompromised population, in particular with specific T-cell defects, including defects in T-helper cell subsets, this is likely to affect their ability to respond to an S aureus vaccine. We urgently need a better understanding of T-cell-mediated immunity in this cohort if an efficacious vaccine is ever to be realized for these patients.

Colonization with multidrug resistant organisms determines the clinical course of patients with acute myeloid leukemia undergoing intensive induction chemotherapy

Introduction

The global spread of multidrug-resistant organisms (MDRO) complicates treatment and isolation measures in hospitals and has shown to increase mortality. Patients with disease- or therapy-related immunodeficiency are especially at risk for fatal infections caused by MDRO. The impact of MDRO colonization on the clinical course of AML patients undergoing intensive induction chemotherapy—a potentially curative but highly toxic treatment option—has not been systematically studied.

Materials & methods

312 AML patients undergoing intensive induction chemotherapy between 2007 and 2015 were examined for MDRO colonization. Patients with evidence for MDRO before or during the hospital stay of induction chemotherapy were defined as colonized, patients who never had a positive swab for MDRO were defined as noncolonized.

Results

Of 312 AML patients 90 were colonized and 130 were noncolonized. Colonized patients suffered from significantly more days with fever, spent more days on the intensive care unit and had a higher median C-reactive protein value during the hospital stay. These findings did not result in a prolonged length of hospital stay or an increased mortality rate for colonized patients. However, in a subgroup analysis, patients colonized with carbapenem-resistant enterobacteriaceae (CRE) had a significantly reduced 60- and 90-day, as well as 1- and 2-year survival rates when compared to noncolonized patients.

Conclusion

Our analysis highlights the importance of intensive MDRO screening especially in patients with febrile neutropenia since persisting fever can be a sign of MDRO-colonization. CRE-colonized patients require special surveillance, since they seem to be at risk for death.

Prevalence of Staphylococcus Species Colonization in Healthy and Sick Cats

Staphylococcus is one of the most frequently isolated genera of opportunistic bacteria in animals and human beings. Staphylococci in mammals mostly inhabit the skin and mucous membranes. The objectives of the study were to investigate the distribution of staphylococcal species in healthy and sick cats in order to find diagnostic markers. The risk factors associated with colonization were also explored. Isolates from healthy (n=520) and sick cats (n=67) were identified at the species level using matrix-assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF MS). Swabs from conjunctival sacs, nares, skin, anus, and wounds were investigated using this technique. The diversity of the Staphylococcus species was high: 26 and 17 species in healthy and sick cats, respectively, and predominantly coagulase-negative staphylococci (CoNS) were isolated. The most frequently observed were S. felis and S. epidermidis in healthy cats, whereas S. felis and S. haemolyticus were most often found in sick animals. S. aureus strains were only isolated from healthy cats, whereas the only coagulase-positive Staphylococcus (CoPS) which occurred in the sick cats group was S. pseudintermedius. The sick, more frequently than the healthy animals, were colonized with S. pseudintermedius and S. haemolyticus and the relationship was statistically significant. Mostly, regardless of the state of their health, similar Staphylococcus species were isolated from cats; therefore, particular attention should be paid during the interpretation of diagnostic results.

[Analysis on risk factors of methicillin-resistant staphylococcus aureus enterocolitis after gastrointestinal surgery]

OBJECTIVE

To investigate the risk factors of methicillin-resistant Staphylococcus aureus(MRSA) enterocolitis after gastrointestinal surgery.

METHODS

Clinical and pathological data of 17 cases with MRSA enteritis after gastrointestinal surgery from March 2015 to March 2017 at Department of General Surgery of Affiliated Drum Tower Hospital were retrospectively analyzed.

INCLUSION CRITERIA

(1) age of 18 to 80 years;(2) with history of gastrointestinal surgery; (3) diarrhea symptoms within 7 days after gastrointestinal surgery; (4) use of antibiotics before diarrhea; (5) fecal smear showing a large number of gram positive cocci; (6) fecal culture suggested the presence of MRSA; (7) application of antibiotic therapy against MRSA was effective.

EXCLUSION CRITERIA

(1)clostridium difficile toxin positive; (2) toxic shock syndrome caused by food poisoning. According to gender, age, and inpatient ward, 1:2 pairing was performed, and 34 patients with non-MRSA enteritis from the hospitalized cases in the same ward were selected as the control group for retrospective case-control study. There were no significant differences in the gender, age, and constitution index between two groups (all P>0.05), indicating that the two groups were comparable. The χ² test was used to perform univariate analysis on 11 factors, including the nature of the primary disease, colorectal surgery, emergency surgery, use of multiple antibiotics, preoperative bowel preparation, perioperative hormone, intraoperative intraperitoneal chemotherapy, perioperative nasogastric tube, diabetes history, intensive care unit stay, and previous infectious disease hospitalization, and then multivariate logistic regression analysis was performed.

RESULTS

MRSA enteritis occurred 3 to 5 days after surgery in all the 17 cases, and 4 cases developed septic shock rapidly. Univariate analysis showed that the operation site (colorectal surgery) (χ²=4.747, P=0.029) and use of two antibiotics before MRSA enteritis (χ²=3.959, P=0.047) were associated with MRSA enteritis after gastrointestinal surgery. Multivariate logistic regression analysis revealed that colorectal surgery was the only independent risk factor for MRSA enteritis after gastrointestinal surgery(OR=5.526, 95%CI: 1.350-22.602,P=0.017), while the use of two antibiotics was not (OR=0.204, 95%CI:0.051-0.819, P=0.025).

CONCLUSIONS

MRSA enteritis has a rapid onset, and a high incidence of septic shock, which requires immediate attention. Colorectal surgery is an independent risk factor for MRSA enteritis.

Acute Tibial osteomyelitis caused by intraosseous access during initial resuscitation: a case report and literature review

BACKGROUND

Intra-osseous (IO) access is recommended in cases of pre-hospital emergency or resuscitation when intravascular (IV) route is difficult or impossible. Despite recent improvement in IO devices and increasing indications, it remains rarely used in practice. Various complications have been reported but are uncommon.

CASE PRESENTATION

We report a case of massive acute tibial osteomyelitis in an adult male three months after an IO catheter insertion for emergency drug infusion. We review the literature on association between IO access and acute osteomyelitis in children and adults.

CONCLUSIONS

Emergency-care givers and radiologists should be informed about this infrequent complication in order to make early diagnosis and initiate adequate antibiotic therapy.

[Encrusted Pyelitis during a case of Thrombotic Thrombocytopenic Purpura]

Encrusted pyelitis is a chronic urinary tract infection associated with mucosal encrustation induced by urea splitting bacteria. More than 40 bacteria have been implicated but the most frequent is Corynebacterium group D2. Predisposing factors are debilitating chronic diseases and preexisting urological procedures. Immunosoppression is an important cofactor. For these reasons the disease is almost always nosocomially acquired and renal transplant recipients are at particular risk. The symptoms are not specific and long lasting: dysuria, flank pain and gross haematuria are the most frequent; fever is present in two-thirds. The demonstration of urine splitting bacteria in constantly alkaline urines and radiological evidence of extensive calcification of pelvicalyceal system, ureter and bladder at US or CT scan in a clinical context of predisposing factors are the mainstay of diagnosis. Treatment is based on adapted antibiotic therapy, acidification of urine and excision of plaques of calcified encrustation. The prognosis relies on timing of diagnosis; delay can be detrimental and result in patient's death and graft loss. We describe a unique case of 69-year-old man with two contemporary diseases: autoimmune thrombotic thrombocytopenic purpura and encrusted pyelitis with a fatal evolution.

Peripheral arterial disease increases the risk of multidrug-resistant bacteria and amputation in diabetic foot infections

Background/aim

The aim of this study was to investigate the microbiological profile and resistance rates of diabetic foot infections (DFIs) and to determine the effect of peripheral arterial disease (PAD) on the microbiology, clinical condition, and treatment outcomes.

Materials and methods

Characteristics, laboratory and imaging data, and the treatment modalities of patients admitted to our hospital with a diagnosis of DFI (PEDIS classification 3–4) during 2005–2016 were analyzed according to the presence of PAD.

Results

Of 112 patients who were included in this study, 86 (76.8%) had PAD. Patients with PAD were older and had higher amputation rates (P < 0.05). A microbiological profile of patients revealed a predominance of gram-positive bacteria (57.1%). Staphylococcus aureus and Streptococcus spp. were the most frequently encountered bacteria. Incidence of Pseudomonas spp. infection was higher in the PAD group (P < 0.05). Of all patients, 24.1% had multidrug-resistant (MDR) microorganisms in their wound cultures. Presence of MDR bacteria in patients with PAD was 4.9-fold higher than that in patients without PAD (P < 0.05).

Conclusion

This retrospective study indicates that PAD has a significant role, especially in elderly patients with DFIs. Patients should be promptly evaluated and treated for PAD to prevent infections with resistant microorganisms and limb loss.

Topical insulin in neurotrophic keratopathy after resection of acoustic neuroma

CASE REPORT

A patient with a history of surgical resection of an acoustic neuroma presented with involvement of both the left facial nerve and the left trigeminal nerve. She initially consulted for exposure keratitis, but two weeks later presented with an infectious keratitis. After taking the corneal sample, she presented with persistent epithelial defect, which did not respond to medical management. Topical insulin was indicated, and a decrease in the area of the lesion was seen in the following 5 days. A therapeutic contact lens was also placed at that time and finally, two weeks after the initiation of insulin, the epithelial defect completely closed.

DISCUSSION

This was a complex case due to the confluence of facial paralysis, neurotrophic keratitis, and infectious keratitis, which finally had a successful outcome. Topical insulin can be an effective adjuvant therapy in cases of neurotrophic ulcers that do not respond to standard therapy.