Computational and in vitro evaluation of probiotic treatments for nasal Staphylococcus aureus decolonization

Despite the rising challenge of antibiotic resistance, current approaches to eradicate nasal pathobionts Staphylococcus aureus and Streptococcus pneumoniae rely on antibacterials. An alternative is the artificial inoculation of commensal bacteria, i.e., probiotic treatment, supported by the increasing evidence for commensal-mediated inhibition of pathogens. To systematically investigate the potential of this approach, we developed a quantitative framework simulating the nasal microbiome dynamics by combining mathematical modeling with longitudinal microbiota data. By inferring community parameters using 16S ribosomal RNA (rRNA) amplicon sequencing data and simulating the nasal microbial dynamics of patients colonized with S. aureus, we compared the decolonization performance of probiotic and antibiotic treatments under different assumptions on patients' community composition and susceptibility profile. To further compare the robustness of these treatments, we simulated an S. aureus challenge and quantified the recolonization probability. Through in vitro experiments using nasal swabs of adults colonized with S. aureus, we confirmed that after antibiotic treatment, recolonization of S. aureus was inhibited in samples treated with a probiotic mixture compared to the nontreated control. Our results suggest that probiotic treatment outperforms antibiotics in terms of decolonization performance, recolonization robustness, and leads to less collateral reduction in the microbiome diversity. Thus, probiotic treatment may provide a promising alternative to combat antibiotic resistance, with the additional advantage of personalized treatment options via using the patient's own metagenomic data. The combination of an in silico framework with in vitro experiments using clinical samples reported in this work is an important step forward to further investigate this alternative in clinical trials.

A novel sacral neuromodulation protocol is associated with reduction in removal for device infection

INTRODUCTION AND HYPOTHESIS

Sacral neuromodulation (SNM) has been established as an effective third-line therapy for non-obstructive urinary retention and urinary urgency-frequency syndrome. Device infection, ranging from 2-10%, is a severe complication usually necessitating device explanation. This study sought to demonstrate an infection protocol founded upon established device implantation risk factors and novel approaches to reduce the incidence of device infection, while maintaining good antibiotic stewardship following best practice statements.

METHODS

A single-surgeon protocol was enacted from 2013 to 2022. Preoperatively, nasal swabs were cultured from each patient. If positive for methicillin-resistant Staphylococcus aureus or methicillin-sensitive Staphylococcus aureus, preoperative treatment with intranasal mupirocin was employed. Preoperative cefazolin was administered in patients with negative cultures or MSSA-positive. All protocol patients were given chlorhexidine wipes before surgery and prepped with a chlorhexidine scrub followed by alcohol/iodine paint. Post-procedural antibiotics were not given. Pre-protocol patients from 2011 to 2013 served as controls.

RESULTS

Pre-protocol (n = 87) patients had a significantly higher rate of device infection compared to protocol patients (n = 444) in both the percentage of patients experiencing device infection (4.6% vs 0.9%, p = 0.01) and percentage of procedures associated with device infection (2.9% vs 0.5%, p < 0.05). A successful culture of the nares was achieved in 91.4% of protocol patients, with 11.6% MRSA-positive. Risk ratio for infection of pre-protocol/protocol patients was 0.19 (0.05-0.77) with odds ratio 5.1 (1.3-20.0).

CONCLUSIONS

Utilization of a novel SNM infection protocol tailored to a patient's preoperative MRSA colonization is associated with a reduction in the overall incidence of explant for device infection while avoiding prolonged postoperative antibiotic regimens.

CLINICAL TRIAL REGISTRATION

The study was initiated prior to January 18, 2017 and does not meet the definition of an applicable clinical trial (ACT) as defined in section 402 (J) of the US PHS Act.

Prevalence of methicillin-resistant Staphylococcus aureus carriage among healthcare workers in South Asia in non-outbreak settings: A systematic review and meta-analysis

BACKGROUND

This study aimed to estimate the pooled prevalence and sub-group-specific prevalence of Methicillin-resistant Staphylococcus aureus (MRSA) carrier rate among Healthcare Workers (HCWs) in South Asia.

METHODOLOGY

We considered prospective and cross-sectional studies published in the English language with participants ≥50 by searching different electronic databases to locate the relevant articles that reported the epidemiology of MRSA. The participants were healthy South Asian nationality HCWs (asymptomatic for any infectious disease) of any age and gender with a definitive diagnosis of MRSA carriage. The result was synthesized for the pooled prevalence of MRSA carriers among HCWs using 95% confidence interval (CI) with DerSimonian and Laird random-effects models.

RESULTS

The pooled prevalence of MRSA carriage among HCWs was 9.23% (95%CI; 6.50%, 12.35%) with a range from 0.67% to 36.06%. The prevalence in India, Nepal, Pakistan, Sri Lanka, and Bangladesh was 5.65% (95%CI; 3.65%, 8.03%), 8.83% (95%CI; 6.77%, 11.11%), 17.20% (95%CI; 10.70%, 24.85%), 22.56% (95%CI; 4.93%, 47.83%), and 4.93% (95%CI; 1.88%, 9.20%) respectively. The pooled prevalence of MRSA carriage among nurses and doctors was 8.90% (95%CI; 6.00%, 12.24%) and 6.53% (95%CI; 3.63%, 10.06%) respectively.

CONCLUSION

The findings from our study suggests that if the propagation of MRSA continues, then it can lead to a situation of an outbreak. Hence, proper preventive measures are to be adopted to prevent this outbreak.

Fabrication of moxifloxacin HCl-loaded biodegradable chitosan nanoparticles for potential antibacterial and accelerated cutaneous wound healing efficacy

AIM

This work aims to formulate topical hybrid gel containing chitosan-coated moxifloxacin (MXF) HCl nanoparticles (NPs) with enhanced antibacterial and healing activity.

METHODS

MXF HCl NPs prepared by the ionic gelation method were loaded onto a hybrid chitosan carbomer gel. Size analysis of the prepared NPs was performed using SEM and Zeta-sizer. Further characterisation was done using Fourier transforms infra-red spectroscopy (FTIR), X-ray diffraction (XRD), and Thermogravimetric analysis (TGA). Prepared gel was evaluated for its in vitro drug release, biocompatibility, antibacterial activity, and stability studies under storage conditions. In-vivo wound healing was measured by observing percentage reduction in wound.

RESULTS

NPs have 359 ± 79 nm mean particle size, 31.01 mV zeta potential with 0.008 polydispersity index (PD1), 63.5% drug entrapment and 83 ± 3.5% drug release at pH 5.5. Hybrid chitosan carbomer gel showed good biocompatibility, antibacterial, in-vivo wound healing properties and stable properties.

CONCLUSIONS

NP-loaded hybrid gel can be an effective treatment for acute and challenged topical wounds.

Role of targeted and universal mupirocin-based decolonization for preventing surgical-site infections in patients undergoing cardiothoracic surgery: A systematic review and meta-analysis

The purpose of the present study was to provide a systematic literature review and pool evidence on the efficacy of mupirocin-based decolonization protocol in reducing surgical-site infections (SSIs) in patients undergoing cardiothoracic (CT) surgery based on their Staphylococcus (S.) aureus carrier state. The PubMed, Embase, Ovid, BioMed Central, Cochrane Central Register of Controlled Trials and Google Scholar databases were searched for studies comparing mupirocin-based decolonization with controls for reducing SSIs in patients following CT surgery. Studies were grouped based on the targeted population of intervention, i.e. carriers or all patients. A total of 17 studies were included. Of these, 8 studies used targeted mupirocin-based decolonization, while universal decolonization was performed in 9 studies. The results were conflicting for studies performing targeted decolonization and it was not possible to perform a meta-analysis due to non-homogenous studies. Pooled analysis of 34,859 patients indicated that universal mupirocin-based decolonization significantly reduced the risk of all SSIs [risk ratio (RR): 0.54; 95% CI: 0.40,0.75; I²=73.35%]. The intervention significantly reduced the risk of superficial SSIs (RR: 0.37; 95% CI: 0.25,0.55; I²=0%) but not of deep SSIs (RR: 0.45; 95% CI: 0.19,1.09; I²=80.67%). The results indicated a significantly reduced risk of S. aureus SSIs (SA-SSIs) with mupirocin-based decolonization (RR: 0.44; 95% CI: 0.32,0.61; I²=0%) but not for methicillin-resistant S. aureus (MRSA-SSIs; RR: 0.25; 95% CI: 0.05,1.28; I²=79.07%). Evidence on the role of targeted mupirocin-based decolonization to reduce SSIs after CT surgery was non-coherent and inconclusive. Analysis of low-quality retrospective studies suggested that universal mupirocin-based decolonization may reduce all SSIs, superficial SSIs and SA-SSIs, but not deep SSIs or MRSA-SSIs in patients after CT surgery.

Decolonization of Staphylococcus aureus

Staphylococcus aureus infections are associated with increased morbidity, mortality, hospital stay, and health care costs. S aureus colonization has been shown to increase risk for invasive and noninvasive infections. Decolonization of S aureus has been evaluated in multiple patient settings as a possible strategy to decrease the risk of S aureus transmission and infection. In this article, we review the recent literature on S aureus decolonization in surgical patients, patients with recurrent skin and soft tissue infections, critically ill patients, hospitalized non-critically ill patients, dialysis patients, and nursing home residents to inform clinical practice.

Antimicrobial photodynamic activity of gallium-substituted haemoglobin on silver nanoparticles

Methicillin-resistant Staphylococcus aureus (MRSA), a major scourge in skin and soft-tissue infections, expresses surface-bound haemoprotein receptors that can be exploited for the targeted delivery of photosensitizers. We have developed a nanosized agent for targeted antimicrobial photodynamic therapy (aPDT), comprised of GaPpIX (a hemin analog with potent photosensitizer activity) encapsulated in haemoglobin (GaHb), mounted on 10 nm Ag nanoparticles (AgNPs). The average GaHb-AgNP contains 28 GaPpIX units stabilized by Hb αβ-dimer units. Eradication (>6-log reduction) of S. aureus and MRSA can be achieved by a 10-second exposure to 405 nm irradiation from a light-emitting diode (LED) array (140 mW cm-2), with GaHb-AgNP loadings as low as 5.6 μg mL-1 for S. aureus and 16.6 μg mL-1 for MRSA, corresponding to nanomolar levels of GaPpIX. This reduction in bacterial count is several orders of magnitude greater than that of GaHb or free GaPpIX on a per mole basis. The GaHb-AgNP platform is also effective against persister MRSA and intracellular MRSA, and can provide comparable levels of aPDT with a 15-minute irradiation by an inexpensive compact fluorescent lightbulb. Collateral phototoxicity to keratinocytes (HaCaT cells) is low at the GaHb-AgNP concentrations and fluences used for aPDT. GaHb adsorbed on 10 nm AgNPs is much more potent than that on 40 nm AgNPs or 10 nm AuNPs, indicating that both size and plasmon-resonant coupling are important factors for enhanced aPDT. Electron microscopy analysis reveals that GaHb-AgNPs are not readily internalized by S. aureus but remain attached to the bacterial cell wall, the likely target of photo-oxidative damage.

Reduction of Postoperative Infections Through Routine Preoperative Universal Decolonization of Advanced Heart Failure Patients With Chlorhexidine and Mupirocin Before Left Ventricular Assist Device Implantation: A Single-Center Observational Study

BACKGROUND

Left ventricular assist devices (LVADs) are increasingly being used in patients with advanced heart failure as bridge to transplant, bridge to decision, or destination therapy. Infections are a major complication associated with LVADs. Staphylococcus aureus is one of the common causative organisms associated with LVAD infections. Methicillin resistant staphylococcus aureus (MRSA)-colonized patients are at an increased risk for developing MRSA-associated infections. Various studies have demonstrated decolonization of skin with topical chlorhexidine and nares with 2% intranasal mupirocin ointment is effective in reducing MRSA-associated infections.

OBJECTIVE

The objective of this observational study was to examine the impact of a universal decolonization protocol using topical chlorhexidine and intranasal mupirocin ointment for 5 days before LVAD implantation on postoperative infections (30, 60, and 90 days) and 30-day infection-related rehospitalization.

METHODS

A preoperative universal decolonization with 4% chlorhexidine daily whole-body bath and 2% intranasal mupirocin ointment twice a day for 5 days was implemented for patients undergoing elective LVAD implantation. Using an observational study design, we included a convenience sample of 84 subjects who were established patients in an accredited advanced heart failure program. Thirty-seven patients served in the standard protocol group, and 47 in the universal decolonization protocol group participated in the observational study.

RESULTS

In the standard protocol group, there were 4 MRSA infections with none in the universal decolonization group (χ = 5.34, P = .03). In total, there were 8 surgical site infections in the standard protocol group and 1 in the universal decolonization group (χ = 5.95, P = .01).

CONCLUSION

A 5-day universal decolonization protocol before LVAD implantation was effective in reducing total infections as well as MRSA-specific infections.

Postoperative empyema following chronic subdural hematoma surgery: Clinically based medicine

INTRODUCTION

Subdural empyema (SDE) is a rare complication of chronic subdural hematoma (CSDH) surgery. We introduced antibiotic prophylaxis (AP) for this procedure in 2014 following a morbidity-mortality conference (MMC) in our department. We report the results of retrospective data analysis to assess the effect of systematic AP and to identify risk factors for SDE.

MATERIAL AND METHODS

Two hundred eight patients were recruited between January 2013 and December 2015; 5 were excluded for incomplete data: 107 without and 96 with AP (n=203). SDE was confirmed by clinical examination, imaging and bacteriological analysis. Comparisons between AP-(no cefuroxime) and AP+ (cefuroxime) groups were made with Chi² test and Student's t-test.

RESULTS

One empyema was found in each group, indicating that AP had no effect (P=1). The only criterion associated with SDE for these two patients was a greater number of reoperations for CSDH recurrence (P=0.013).

DISCUSSION

The incidence of postoperative empyema was 1%, similar to the range of 0.2%-2.1% reported in the literature. This rare incidence explains why we found no significant effect of AP. The medical decision taken at the MMC did not help to reduce the rate of postoperative SDE. MMCs can help to define factors associated with adverse surgical events and identify opportunities for improvement.

CONCLUSION

AP, introduced after an MMC, did not impact SDE rates. In practice, AP should be required only in case of reoperation for CSDH recurrence. However, we still continue to use AP following the MMC considering different parameters discussed in the manuscript.

Article Commentary: The Continued Challenge of Staphylococcus aureus in the Surgical Patient

Staphylococcus aureus continues to be a common pathogen from community-acquired infections and for infections after surgical procedures. A review of the history of this pathogen indicates that it will likely continue to develop new virulence characteristics and that it will continue to develop new patterns of resistance. This presentation addresses the three major areas for surgeons in the future. First, vancomycin is losing its effectiveness against methicillin-resistant S. aureus (MRSA). The future antibiotic choices for treating this pathogen are discussed. Second, vancomycin is losing its effectiveness for prevention of MRSA infections at the surgical site, and another antibiotic choice needs to be developed for prevention of both methicillin-sensitive and methicillin-resistant staphylococci. Third, decolonization of staphylococci from the nasopharynx is discussed commonly in the literature, but valid evidence for this practice is limited. Controlled clinical trials to prevent surgical site infection by decolonization with mupirocin or other agents are needed. In summary, S. aureus will continue to challenge surgeons as an adaptable pathogen that can defy all of our treatment efforts.

Development of Chitosan-Based Hydrogel Containing Antibiofilm Agents for the Treatment of Staphylococcus aureus-Infected Burn Wound in Mice

Methicillin-resistant Staphylococcus aureus (MRSA) is considered a common colonizer of burn wound and accounts for high morbidity and mortality all across the globe. Systemic antibiotic therapy which is generally prescribed for these patients has a number of limitations. These include high drug dose, toxicity, and chances of development of drug resistance. However, local delivery of drug not only addresses these limitations but also provides better efficacy at the site of infection. In the present study, hydrogel preparations were developed for the topical delivery of moxifloxacin for the treatment of S. aureus-infected burn wound. Moxifloxacin was characterized by UV, FTIR, DSC, hot-stage microscopy, NMR, and HPLC and loaded into conventional and Boswellia-containing novel gels. Gels were characterized by visual examination, pH, UV spectroscopy, and release assays. In vivo studies showed that both gels were effective in eradicating the bacteria completely from the wound site when treatment was started during the early stage of infection. On the contrary, delayed treatment of planktonic and biofilm cells with novel gel showed better efficacy as compared with conventional gel in S. aureus-infected burn wound. Histopathological analysis also showed better skin healing efficacy of novel gel than conventional gel. Our results show that moxifloxacin can be efficiently used topically in the management of burn wound infections along with other antibacterial agents. Since biofilm-mediated infections are on the rise especially in chronic bacterial disease, therefore, a preparation containing antibiofilm agent-like Boswellia as one of the excipients would be more meaningful.

Surgical Site Infections in Aesthetic Surgery

Surgical site infections represent one of the most common postoperative complications in patients undergoing aesthetic surgery. As with other postoperative complications, the incidence of these infections may be influenced by many factors and varies depending on the specific operation performed. Understanding the risk factors for infection development is critical because careful patient selection and appropriate perioperative counseling will set the right expectations and can ultimately improve patient outcomes and satisfaction. Various perioperative prevention measures may also be employed to minimize the incidence of these infections. Once the infection occurs, prompt diagnosis will allow management of the infection and any associated complications in a timely manner to ensure patient safety, optimize the postoperative course, and avoid long-term sequelae.

The Continuing Threat of Methicillin-Resistant Staphylococcus aureus

Staphylococcus aureus has been an exceptionally successful pathogen, which is still relevant in modern age-medicine due to its adaptability and tenacity. This bacterium may be a causative agent in a plethora of infections, owing to its abundance (in the environment and in the normal flora) and the variety of virulence factors that it possesses. Methicillin-resistant S. aureus (MRSA) strains—first described in 1961—are characterized by an altered penicillin-binding protein (PBP2a/c) and resistance to all penicillins, cephalosporins, and carbapenems, which makes the β-lactam armamentarium clinically ineffective. The acquisition of additional resistance determinants further complicates their eradication; therefore, MRSA can be considered as the first representative of multidrug-resistant bacteria. Based on 230 references, the aim of this review is to recap the history, the emergence, and clinical features of various MRSA infections (hospital-, community-, and livestock-associated), and to summarize the current advances regarding MRSA screening, typing, and therapeutic options (including lipoglycopeptides, oxazolidinones, anti-MRSA cephalosporins, novel pleuromutilin-, tetracycline- and quinolone-derivatives, daptomycin, fusidic acid, in addition to drug candidates in the development phase), both for an audience of clinical microbiologists and infectious disease specialists.

The effect of preoperative oral antibiotic use on the risk of periprosthetic joint infection after primary knee or hip replacement: a retrospective study with a 1-year follow-up

OBJECTIVES

Antibiotics are used for various reasons before elective joint replacement surgery. The aim of this study was to investigate patients' use of oral antibiotics before joint replacement surgery and how this affects the risk for periprosthetic joint infection (PJI).

METHODS

Patients having a primary hip or knee replacement in a tertiary care hospital between September 2002 and December 2013 were identified (n = 23 171). Information on oral antibiotic courses purchased 90 days preoperatively and patients' chronic diseases was gathered. Patients with a PJI in a 1-year follow-up period were identified. The association between antibiotic use and PJI was examined using a multivariable logistic regression model and propensity score matching.

RESULTS

One hundred and fifty-eight (0.68%) cases of PJI were identified. In total, 4106 (18%) joint replacement operations were preceded by at least one course of antibiotics. The incidence of PJI for patients with preoperative use of oral antibiotics was 0.29% (12/4106), whereas for patients without antibiotic use it was 0.77% (146/19 065). A preoperative antibiotic course was associated with a reduced risk for subsequent PJI in the multivariable model (OR 0.40, 95% CI 0.22-0.73). Similar results were found in the propensity score matched material (OR 0.34, 95% CI 0.18-0.65).

CONCLUSIONS

The use of oral antibiotics before elective joint replacement surgery is common and has a potential effect on the subsequent risk for PJI. Nevertheless, indiscriminate use of antibiotics before elective joint replacement surgery cannot be recommended, even though treatment of active infections remains an important way to prevent surgical site infections.

Antimicrobial Resistance to Agents Used for Staphylococcus aureus Decolonization: Is There a Reason for Concern?

PURPOSE OF REVIEW

Chlorhexidine gluconate (CHG) and mupirocin are increasingly used for Staphylococcus aureus decolonization to prevent healthcare-associated infections; however, increased use of these agents has led to concerns for growing resistance and reduced efficacy. In this review, we describe current understanding of reduced susceptibility to CHG and mupirocin in S. aureus and their potential clinical implications.

RECENT FINDINGS

While emergence of S. aureus tolerant or resistant to topical antimicrobial agents used for decolonization is well described, the clinical impact of reduced susceptibility is not clear. Important challenges are that standardized methods of resistance testing and interpretation are not established, and the risk for selection for co- or cross-resistance using universal, as opposed to targeted decolonization, is unclear. Evidence continues to support S. aureus decolonization in certain patient groups, although further studies are needed to determine the long-term impact of CHG and mupirocin resistance on efficacy. Strategies to mitigate further development of reduced susceptibility and the consequences of selection pressures through universal decolonization on resistance will benefit from further investigation.

Prevalence of Staphylococcus spp. nasal colonization among doctors of podiatric medicine and associated risk factors in Spain

Background

This study aimed to estimate the prevalence of methicillin-susceptible and -resistant Staphylococcus aureus (MSSA and MRSA) and methicillin-resistant Staphylococcus epidermidis (MRSE) nasopharyngeal carriage among Doctors of Podiatric Medicine (Podiatrists) and to determine the potential risk factors.

Methods

A cross-sectional study was carried out in 2016-2017 among 239 podiatrists in Spain. The presence of MSSA, MRSA, and MRSE was determined by microbiological analysis of nasal exudate and antimicrobial susceptibility was determined. Each podiatrist completed a questionnaire. The questionnaire comprised various parameters such as sex, age, podiatry experience duration, underlying diseases, prior antibiotic treatment, hospitalization during the last year, and use of a protective mask, an aspiration system, or gloves.

Results

The prevalence of MSSA, MRSA, and MRSE was 23.0%, 1.3%, and 23.8%, respectively. The MSSA prevalence was higher among podiatrists who did not use an aspiration system (32.3%) compared to those who did (19.3%; p = 0.0305), and among podiatrists with respiratory diseases (36.8%) compared to those without (20.8%; p = 0.0272). The MRSE prevalence was higher among men (33.7%) compared to women (8.6%; p = 0.0089), podiatrists aged ≥50 (38.5%) compared to ≤35 (17.8%; p = 0.0101), and podiatrists with ≥15 (39.3%) compared to ≤5 years of podiatry experience (12.5%; p = 0.0015). Among the S. aureus strains, 84.5% were resistant to penicillin, 22.4% to erythromycin, 20.7% to clindamycin, and 12.7% to mupirocin. The MRSE strains were resistant to penicillin (93.0%), erythromycin (78.9%), and mupirocin (73.7%).

Conclusions

The prevalence of S. aureus and S. epidermidis nasal carriage is low among Spanish podiatrists compared to other health professionals.

Impact of Systemic Antibiotics on Staphylococcus aureus Colonization and Recurrent Skin Infection

Background

Staphylococcus aureus colonization poses risk for subsequent skin and soft tissue infection (SSTI). We hypothesized that including systemic antibiotics in the management of S. aureus SSTI, in conjunction with incision and drainage, would reduce S. aureus colonization and incidence of recurrent infection.

Methods

We prospectively evaluated 383 children with S. aureus SSTI requiring incision and drainage and S. aureus colonization in the anterior nares, axillae, or inguinal folds at baseline screening. Systemic antibiotic prescribing at the point of care was recorded. Repeat colonization sampling was performed within 3 months (median, 38 days; interquartile range, 22-50 days) in 357 participants. Incidence of recurrent infection was ascertained for up to 1 year.

Results

Participants prescribed guideline-recommended empiric antibiotics for purulent SSTI were less likely to remain colonized at follow-up sampling (adjusted hazard ratio [aHR], 0.49; 95% confidence interval [CI], .30-.79) and less likely to have recurrent SSTI (aHR, 0.57; 95% CI, .34-.94) than those not receiving guideline-recommended empiric antibiotics for their SSTI. Additionally, participants remaining colonized at repeat sampling were more likely to report a recurrent infection over 12 months (aHR, 2.37; 95% CI, 1.69-3.31). Clindamycin was more effective than trimethoprim-sulfamethoxazole (TMP-SMX) in eradicating S. aureus colonization (44% vs 57% remained colonized, P = .03) and preventing recurrent SSTI (31% vs 47% experienced recurrence, P = .008).

Conclusions

Systemic antibiotics, as part of acute SSTI management, impact S. aureus colonization, contributing to a decreased incidence of recurrent SSTI. The mechanism by which clindamycin differentially affects colonization and recurrent SSTI compared to TMP-SMX warrants further study.

Decolonization of Staphylococcus aureus in patients with atopic dermatitis: a reason for increasing resistance to antibiotics?

INTRODUCTION

Exacerbation of atopic dermatitis can be associated with bacterial infection. The skin of patients is colonized with Staphylococcus aureus in 90% of cases. An attempt has been made to demonstrate that eradication significantly reduces the severity of the disease. Studies indicate the efficacy of topical antibiotics, topical corticosteroids and calcineurin inhibitors. Due to increasing resistance to drugs and the defective antimicrobial peptide profile, decolonization is virtually impossible.

AIM

To determine the prevalence of S. aureus colonization among patients with atopic dermatitis and to assess antimicrobial susceptibility of isolated strains to antibiotics, especially fusidic acid and mupirocin.

MATERIAL AND METHODS

One hundred patients with atopic dermatitis and 50 healthy subjects were microbiologically assessed for the carriage of S. aureus. Antimicrobial susceptibility tests were performed using the broth-microdilution method for antibiotics: ampicillin, ciprofloxacin, daptomycin, erythromycin, fusidic acid, linezolid, lincomycin, mupirocin, tetracycline and vancomycin.

RESULTS

Staphylococcus aureus strains were isolated from the majority of our patients, either from the skin (71%) or the anterior nares (67%). In the present study, 10% of isolations represented methicillin-resistant S. aureus (MRSA). Antibiotics exhibited diverse activities against clinical isolates of S. aureus. Among those tested, the highest rates of resistance were shown for ampicillin - 58.5%, lincomycin - 37.5% and erythromycin - 31.0%. Enhanced resistance levels were expressed to mupirocin (17.5%) and fusidic acid (15.5%).

CONCLUSIONS

According to the increasing rate of resistance and quick recolonization after discontinuation of the treatment, chronic use of topical antibiotics is not recommended and should be limited to exacerbation of atopic dermatitis with clinical signs of bacterial infection.

Recommendations for approaches to meticillin-resistant staphylococcal infections of small animals: diagnosis, therapeutic considerations and preventative measures.: Clinical Consensus Guidelines of the World Association for Veterinary Dermatology

BACKGROUND

Multiple drug resistance (MDR) in staphylococci, including resistance to the semi-synthetic penicillinase-resistant penicillins such as meticillin, is a problem of global proportions that presents serious challenges to the successful treatment of staphylococcal infections of companion animals.

OBJECTIVES

The objective of this document is to provide harmonized recommendations for the diagnosis, prevention and treatment of meticillin-resistant staphylococcal infections in dogs and cats.

METHODS

The authors served as a Guideline Panel (GP) and reviewed the literature available prior to September 2016. The GP prepared a detailed literature review and made recommendations on selected topics. The World Association of Veterinary Dermatology (WAVD) provided guidance and oversight for this process. A draft of the document was presented at the 8th World Congress of Veterinary Dermatology (May 2016) and was then made available via the World Wide Web to the member organizations of the WAVD for a period of three months. Comments were solicited and posted to the GP electronically. Responses were incorporated by the GP into the final document.

CONCLUSIONS

Adherence to guidelines for the diagnosis, laboratory reporting, judicious therapy (including restriction of use policies for certain antimicrobial drugs), personal hygiene, and environmental cleaning and disinfection may help to mitigate the progressive development and dissemination of MDR staphylococci.

Povidone-Iodine-Based Solutions for Decolonization of Nasal Staphylococcus aureus: A Randomized, Prospective, Placebo-Controlled Study

BACKGROUND

Nasal Staphylococcus aureus decolonization reduces the risk of surgical site infections after orthopedic procedures. Povidone-iodine (PI)-based solutions have shown promising results in bacteria decolonization. The unique physiology of the nose may pose challenges for the bioactivity profiles of PI solutions. This study compared the antibacterial efficacy of an off-the-shelf PI product with a specifically manufactured PI-based skin and nasal antiseptic (SNA).

METHODS

This randomized, placebo-controlled study was conducted at a single institution between April 2014 and July 2015. Four hundred and twenty-nine patients undergoing primary or revision total joint arthroplasty, femoroacetabular osteoplasty, pelvic osteotomy, or total shoulder arthroplasty were included. 10% off-the-shelf PI, 5% PI-based SNA, or saline (placebo) were used for nasal decolonization. Baseline cultures were taken immediately preoperatively, followed by treatment of both nares twice for 2 minutes with 4 applicators. Reculturing of the right nostril occurred at 4 hours and the left at 24 hours.

RESULTS

Ninety-five of the 429 patients (22.1%) had a positive culture result for S. aureus; 13 (3.03%) were methicillin-resistant S. aureus. Of these 95, 29 were treated with off-the-shelf PI, 34 with SNA, and 32 with saline swabs. At 4 hours post-treatment, S. aureus culture was positive in 52% off-the-shelf PI patients, 21% SNA patients, and 59% saline patients. After 24 hours posttreatment, S. aureus culture was positive in 72% off-the-shelf PI patients, 59% SNA patients, and 69% saline group. SNA was significantly more effective at decolonizing S. aureus over the 4-hour time interval (P = .003); no significant difference was observed over the 24-hour time interval between the 3 groups.

CONCLUSION

A single application of PI-based SNA before surgery may be effective in eliminating nasal S. aureus in over two-thirds of patients. Off-the-shelf PI swabs were not as effective at 4 hours as the specifically manufactured product for S. aureus decolonization.

Mupirocin in the Treatment of Staphylococcal Infections in Chronic Rhinosinusitis: A Meta-Analysis

Background

Saline irrigation of the nasal cavity is a classic and effective treatment for acute or chronic rhinosinusitis. Topical antibiotics such as mupirocin have been widely used for recalcitrant chronic rhinosinusitis. Therefore, the purpose of this study was to evaluate the effect of saline irrigation using mupirocin.

Methods

A systematic literature review and meta-analysis of mupirocin saline irrigation were performed using EMBASE, MEDLINE, and Cochrane library through December 2015. Data were analyzed with R 3.2.2 software. A random effects model was used because of the diversity of included studies. Sensitivity analysis of particular tested groups and single proportion tests were also performed. The main outcome measure was residual staphylococcal infection, as confirmed by culture or PCR.

Results

Two RCTs, two prospective studies and two retrospective studies were included. A random effects model meta-analysis of the pooled data identified a relative risk of residual infection of 0.13 (95% CI: 0.06–0.26, p<0.05) with low heterogeneity (I² = 0%). The proportion of residual staphylococcal infections after 1 month was 0.08 (95% CI: 0.04–0.16). However, this proportion increased to 0.53 at 6 months (95% CI: 0.27–0.78).

Conclusions

The short-term use of mupirocin has a strongly reductive effect on staphylococcal infection in chronic rhinosinusitis. Although there is currently a lack of clear evidence, future studies with well-designed inclusion criteria and randomized controlled trials are needed to examine mupirocin’s long-term effect on chronic rhinosinusitis.

Synthesis and antimicrobial activity of tetradentate ligands bearing hydrazone and/or thiosemicarbazone motifs and their diorganotin(IV) complexes

Four novel ligands derived from 2,3-butanedione have been synthesized, two dissymmetric thiosemicarbazone/3-hydroxy-2-naphthohydrazone ligands, H₂L¹ (bearing 4-isopropyl-3-thiosemicarbazone) and H₂L² (containing 4-cyclohexyl-3-thiosemicarbazone) and the symmetric H₂L³, diacetyl bis(3-hydroxy-2-naphthohydrazone), and H₂L⁴, diacetyl bis(4-cyclohexyl-3-thiosemicarbazone). Their reactivity with SnR₂Cl₂ (R=methyl, n-butyl and phenyl) was explored and the resulting complexes were characterized by elemental analysis, molar conductivity, mass spectrometry, IR, ¹H, ¹³C and ¹¹⁹Sn NMR and seven of them also by single crystal X-ray diffraction. The results showed that the reactivity of the dissymmetric ligands is strongly different and while the cyclohexyl derivative is very stable, with isopropyl easily undergoes a symmetrization reaction to yield the corresponding symmetric ligands. The antimicrobial activity of the ligands and the corresponding diorganotin(IV) complexes was investigated in vitro against seven species of microorganisms and minimum inhibitory concentrations (MICs) were determined. The results showed that the ligand H₂L² and several of its derivatives, together with methyl and phenyl complexes of H₂L¹, have the ability of inhibiting the growth of tested bacteria and fungi to different extents. Bacillus subtilis and Staphylococcus aureus Gram positive strains were the most sensitive microorganisms.

Prevention of Recurrent Staphylococcal Skin Infections

Staphylococcus aureus infections pose a significant health burden. The emergence of community-associated methicillin-resistant S aureus has resulted in an epidemic of skin and soft tissue infections (SSTI), and many patients experience recurrent SSTI. As S aureus colonization is associated with subsequent infection, decolonization is recommended for patients with recurrent SSTI or in settings of ongoing transmission. S aureus infections often cluster within households, and asymptomatic carriers serve as reservoirs for transmission; therefore, a household approach to decolonization is more effective than measures performed by individuals alone. Novel strategies for the prevention of recurrent SSTI are needed.

Cold plasma inactivation of chronic wound bacteria

Cold plasma is partly ionized non-thermal plasma generated at atmospheric pressure. It has been recognized as an alternative approach in medicine for sterilization of wounds, promotion of wound healing, topical treatment of skin diseases with microbial involvement and treatment of cancer. Cold plasma used in wound therapy inhibits microbes in chronic wound due to its antiseptic effects, while promoting healing by stimulation of cell proliferation and migration of wound relating skin cells. In this study, two types of plasma systems are employed to generate cold plasma: a parallel plate dielectric barrier discharge and a capillary-guided corona discharge. Parameters such as applied voltage, discharge frequency, treatment time and the flow of the carrier gas influence the cold plasma chemistry and therefore change the composition and concentration of plasma species that react with the target sample. Chronic wound that fails to heal often infected by multidrug resistant organisms makes them recalcitrant to healing. Methicillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa (Pseudomonas aeruginosa) are two common bacteria in infected and clinically non-infected wounds. The efficacies of the cold plasma generated by the two designs on the inactivation of three different isolates of MRSA and four isolates of P. aeruginosa are reported here.

Staphylococcus Infections in Pregnancy: Maternal and Neonatal Risks

Staphylococcus aureus is carried by up to one third of the general population; about 2% are carriers for methicillin-resistant S. aureus (MRSA). Infections caused by the antibiotic-resistant form include skin and soft tissue infections, as well as pneumonia, sepsis, and wound infections. Although the risks of hospital-associated systemic infections have decreased with attention to infection control procedures, serious obstetric illness remains a concern. This article describes the range of MRSA infection in the setting of pregnancy and discusses risks to both mother and newborn associated with active MRSA infection during pregnancy and childbirth. Methicillin-resistant S. aureus remains a risk to mothers and newborns, requiring prompt identification and appropriate management.

In Vitro Activity of Retapamulin and Antimicrobial Susceptibility Patterns in a Longitudinal Collection of Methicillin-Resistant Staphylococcus aureus Isolates from a Veterans Affairs Medical Center

Mupirocin is a topical antimicrobial used to decolonize patients who carry methicillin-resistant Staphylococcus aureus (MRSA), and the topical agent retapamulin may be a potential alternative therapy. The goal of this study was to determine the in vitro activity of retapamulin as well as a panel of 15 antimicrobial agents, including mupirocin, for 403 MRSA isolates collected longitudinally from a naive population at the Veterans Affairs Puget Sound Health Care System. The MICs for retapamulin had a unimodal distribution, ranging from 0.008 to 0.5 μg/ml. One isolate had an MIC of >16 μg/ml, was also resistant to clindamycin and erythromycin, and was recovered from the nares of a patient undergoing hemodialysis. Twenty-four isolates (6%) and 11 isolates (3%) demonstrated low-level resistance (MICs of 8 to 64 μg/ml) and high-level resistance (MICs of ≥ 512 μg/ml), respectively, to mupirocin. Isolates were recovered from 10 patients both before and after mupirocin therapy. Of those, isolates from 2 patients demonstrated MIC changes postmupirocin therapy; in both cases, however, strain typing demonstrated that the pre- and postmupirocin strains were different. A total of 386 isolates (96%) had vancomycin MICs of ≤ 1.0 μg/ml; 340 isolates (84%) were resistant to levofloxacin, 18 isolates (4.5%) were resistant to trimethoprim-sulfamethoxazole, and 135 isolates (33%) had elevated MICs of 4 μg/ml for linezolid. The baseline levels of resistance were low for mupirocin (9%) and even lower for retapamulin (0.25%) Although the use of mupirocin is currently the standard therapy for decolonization practices, the activity of retapamulin warrants its consideration as an alternative therapy in MRSA decolonization regimens.

Methicillin-resistant Staphylococcus aureus (MRSA) nasal real-time PCR: a predictive tool for contamination of the hospital environment

OBJECTIVE We sought to determine whether the bacterial burden in the nares, as determined by the cycle threshold (CT) value from real-time MRSA PCR, is predictive of environmental contamination with MRSA. METHODS Patients identified as MRSA nasal carriers per hospital protocol were enrolled within 72 hours of room admission. Patients were excluded if (1) nasal mupirocin or chlorhexidine body wash was used within the past month or (2) an active MRSA infection was suspected. Four environmental sites, 6 body sites and a wound, if present, were cultured with premoistened swabs. All nasal swabs were submitted for both a quantitative culture and real-time PCR (Roche Lightcycler, Indianapolis, IN). RESULTS At study enrollment, 82 patients had a positive MRSA-PCR. A negative correlation of moderate strength was observed between the CT value and the number of MRSA colonies in the nares (r=-0.61; P<0.01). Current antibiotic use was associated with lower levels of MRSA nasal colonization (CT value, 30.2 vs 27.7; P<0.01). Patients with concomitant environmental contamination had a higher median log MRSA nares count (3.9 vs 2.5, P=0.01) and lower CT values (28.0 vs 30.2; P<0.01). However, a ROC curve was unable to identify a threshold MRSA nares count that reliably excluded environmental contamination. CONCLUSIONS Patients with a higher burden of MRSA in their nares, based on the CT value, were more likely to contaminate their environment with MRSA. However, contamination of the environment cannot be predicted solely by the degree of MRSA nasal colonization.

Effect of maternal skin-to-skin contact on decolonization of Methicillin-Oxacillin-Resistant Staphylococcus in neonatal intensive care units: a randomized controlled trial

Background

Decolonization with topical antibiotics is necessary to control outbreaks of multidrug-resistant bacterial infection in the Neonatal Intensive Care Unit (NICU), but can trigger bacterial resistance. The objective of this study was to determine whether skin-to-skin contact of newborns colonized with Methicillin-Oxacillin Resistant Staphylococcus aureus or Methicillin-Oxacillin-Resistant Coagulase-Negative Staphylococcus aureus (MRSA/MRSE) with their mothers could be an effective alternative to promote bacterial decolonization of newborns’ nostrils.

Methods

We performed a randomized clinical trial with 102 newborns admitted to the NICU in three hospitals in São Luís, Brazil. Inclusion criteria were birth weight of 1300 to 1800 g, more than 4 days of hospitalization, newborns with positive nostril cultures for MRSA and/or multidrug-resistant coagulase-negative Staphylococcus and mothers not colonized by these bacteria. We used a random number algorithm for randomization. Allocation was performed using sealed opaque envelopes. Skin-to-skin contact was given twice a day for 60 minutes for seven consecutive days. The control group received routine care without skin-to-skin contact. There was no masking of newborn’s mothers or researchers but the individuals who carried out bacterial cultures and assessed results were kept blind to group allocation. The primary outcome was colonization status of newborns’ nostrils after 7 days of intervention. The directional hypothesis was that more newborns who receive skin-to-skin holding 2 hours/day for 7 days than newborns who receive normal care will be decolonized.

Results

Decolonization of MRSA/MRSE was greater in the intervention group (Risk Ratio = 2.27; 95% CI 1.27-4.07, p-value = 0.003). Number Needed to Treat (NNT) was 4.0 (95% CI 2.2 – 9.4). After adjustment for the possible confounding effects of small for gestational age birth, antibiotic use, need for resuscitation, sex and cesarean delivery, skin-to-skin contact remained strongly associated with decolonization of newborns’ nostrils from MRSA/MRSE bacteria (p = 0.007). There was no need to interrupt the trial for safety reasons.

Conclusion

Skin-to-skin contact might be an effective and safe method for promoting decolonization of newborns’ nostrils colonized by MRSA/MRSE.

Trial Registration

The study was registered with ClinicalTrials.gov (NCT01498133, November 21, 2011).

Comprehensive review of methicillin-resistant Staphylococcus aureus: screening and preventive recommendations for plastic surgeons and other surgical health care providers

BACKGROUND

Up to 2.3 million people are colonized with methicillin-resistant Staphylococcus aureus in the United States, causing well-documented morbidity and mortality. Although the association of clinical outcomes with community and hospital carriage rates is increasingly defined, less is reported about asymptomatic colonization prevalence among physicians, and specifically plastic surgeons and the subsequent association with the incidence of patient surgical-site infection.

METHODS

A review of the literature using the PubMed and Cochrane databases analyzing provider screening, transmission, and prevalence was undertaken. In addition, a search was completed for current screening and decontamination guidelines and outcomes.

RESULTS

The methicillin-resistant S. aureus carriage prevalence of surgical staff is 4.5 percent. No prospective data exist regarding transmission and interventions for plastic surgeons. No studies were found specifically looking at prevalence or treatment of plastic surgeons. Current recommendations by national organizations focus on patient-oriented point-of-care testing and intervention, largely ignoring the role of the health care provider. Excellent guidelines exist regarding screening, transmission prevention, and treatment both in the workplace and in the community. No current such guidelines exist for plastic surgeons.

CONCLUSIONS

No Level I or II evidence was found regarding physician screening, treatment, or transmission. Current expert opinion, however, indicates that plastic surgeons and their staff should be vigilant for methicillin-resistant S. aureus transmission, and once a sentinel cluster of skin and soft-tissue infections is identified, systematic screening and decontamination should be considered. If positive, topical decolonization therapy should be offered. In refractory cases, oral antibiotic therapy may be required, but this should not be used as a first-line strategy.

Topical delivery of ultrahigh concentrations of gentamicin is highly effective in reducing bacterial levels in infected porcine full-thickness wounds

BACKGROUND

Injury to the skin can predispose individuals to invasive infection. The standard of care for infected wounds is treatment with intravenous antibiotics. However, antibiotics delivered intravenously may have poor tissue penetration and be dose limited by systemic side effects. Topical delivery of antibiotics reduces systemic complications and delivers increased drug concentrations directly to the wound.

METHODS

Porcine full-thickness wounds infected with Staphylococcus aureus were treated with ultrahigh concentrations (over 1000 times the minimum inhibitory concentration) of gentamicin using an incubator-like wound healing platform. The aim of the present study was to evaluate clearance of infection and reduction in inflammation following treatment. Gentamicin cytotoxicity was evaluated by in vitro assays.

RESULTS

Application of 2000 μg/ml gentamicin decreased bacterial counts in wound tissue from 7.2 ± 0.3 log colony-forming units/g to 2.6 ± 0.6 log colony-forming units/g in 6 hours, with no reduction observed in saline controls (p < 0.005). Bacterial counts in wound fluid decreased from 5.7 ± 0.9 log colony-forming units/ml to 0.0 ± 0 log colony-forming units/ml in 1 hour, with no reduction observed in saline controls (p < 0.005). Levels of interleukin-1β were significantly reduced in gentamicin-treated wounds compared with saline controls (p < 0.005). In vitro, keratinocyte migration and proliferation were reduced at gentamicin concentrations between 100 and 1000 μg/ml.

CONCLUSIONS

Topical delivery of ultrahigh concentrations of gentamicin rapidly decontaminates acutely infected wounds and maintains safe systemic levels. Treatment of infected wounds using the proposed methodology protects the wound and establishes a favorable baseline for subsequent treatment.

Cost-Effectiveness of Preoperative Nasal Mupirocin Treatment in Preventing Surgical Site Infection in Patients Undergoing Total Hip and Knee Arthroplasty: A Cost-Effectiveness Analysis

Objective.

To perform a cost-effectiveness analysis to evaluate preoperative use of mupirocin in patients with total joint arthroplasty (TJA).

Design.

Simple decision tree model.

Setting.

Outpatient TJA clinical setting.

Participants.

Hypothetical cohort of patients with TJA.

Interventions.

A simple decision tree model compared 3 strategies in a hypothetical cohort of patients with TJA: (1) obtaining preoperative screening cultures for all patients, followed by administration of mupirocin to patients with cultures positive for Staphylococcus aureus; (2) providing empirical preoperative treatment with mupirocin for all patients without screening; and (3) providing no preoperative treatment or screening. We assessed the costs and benefits over a 1-year period. Data inputs were obtained from a literature review and from our institution's internal data. Utilities were measured in quality-adjusted life-years, and costs were measured in 2005 US dollars.

Main Outcome Measure.

Incremental cost-effectiveness ratio.

Results.

The treat-all and screen-and-treat strategies both had lower costs and greater benefits, compared with the no-treatment strategy. Sensitivity analysis revealed that this result is stable even if the cost of mupirocin was over $100 and the cost of SSI ranged between $26,000 and $250,000. Treating all patients remains the best strategy when the prevalence of S. aureus carriers and surgical site infection is varied across plausible values as well as when the prevalence of mupirocin-resistant strains is high.

Conclusions.

Empirical treatment with mupirocin ointment or use of a screen-and-treat strategy before TJA is performed is a simple, safe, and cost-effective intervention that can reduce the risk of SSI. S. aureus decolonization with nasal mupirocin for patients undergoing TJA should be considered.

Level of Evidence.

Level II, economic and decision analysis.

Infect Control Hosp Epidemiol 2012;33(2):152-159

Systematic literature analysis and review of targeted preventive measures to limit healthcare-associated infections by meticillin-resistant Staphylococcus aureus

Meticillin-resistant Staphylococcus aureus (MRSA) is a major cause of healthcare-associated infections in Europe. Many examples have demonstrated that the spread of MRSA within healthcare settings can be reduced by targeted infection control measures. The aim of this systematic literature analysis and review was to summarise the evidence for the use of bacterial cultures for active surveillance the benefit of rapid screening tests, as well as the use of decolonisation therapies and different types of isolation measures. We included 83 studies published between 2000 and 2012. Although the studies reported good evidence supporting the role of active surveillance followed by decolonisation therapy, the effectiveness of single-room isolation was mostly shown in non-controlled studies, which should inspire further research regarding this issue. Overall, this review highlighted that when planning the implementation of preventive interventions, there is a need to consider the prevalence of MRSA, the incidence of infections, the competing effect of standard control measures (e.g. hand hygiene) and the likelihood of transmission in the respective settings of implementation.

Cationic methacrylate polymers as topical antimicrobial agents against Staphylococcus aureus nasal colonization

The in vitro and in vivo antimicrobial activity of primary ammonium ethyl methacrylate homopolymers (AEMPs) was investigated. AEMPs with different degrees of polymerization (DP = 7.7–12) were prepared by reversible addition–fragmentation chain-transfer (RAFT) polymerization. The AEMPs showed higher inhibitory effects against Gram-positive bacteria, including methicillin-resistant Staphylococcus aureus (MRSA), than Gram-negative bacteria. The AEMPs also showed potent anti-S. aureus activity in the presence of fetal bovine serum, whereas the activity of the antibiotic mupirocin was reduced under the same conditions. The AEMPs showed very little or no hemolytic activity. The cytotoxicity of AEMPs against mammalian cells HEp-2 and COS-7 was concentration-dependent, and the cell viability significantly decreased at higher polymer concentrations. The AEMPs significantly reduced the number of viable S. aureus cells in the nasal environment of cotton rats when compared to that of the control. This study demonstrates that AEMPs have potential for use in treating topical S. aureus infections.

Patient experience with mupirocin or povidone-iodine nasal decolonization

Led by the federal government, the payers of health care are enacting policies designed to base provider reimbursement on the quality of care they render. This study evaluated and compared patient experiences and satisfaction with nasal decolonization with either nasal povidone-iodine (PI) or nasal mupirocin ointment (MO). A total of 1903 patients were randomized to undergo preoperative nasal decolonization with either nasal MO or PI solution. All randomized patients were also given 2% chlorhexidine gluconate topical wipes. Patients were interviewed prior to discharge to assess adverse events and patient experience with their assigned preoperative antiseptic protocol. Of the 1903 randomized patients, 1679 (88.1%) were interviewed prior to discharge. Of patients receiving PI, 3.4% reported an unpleasant or very unpleasant experience, compared with 38.8% of those using nasal MO (P<.0001). Sixty-seven percent of patients using nasal MO believed it to be somewhat or very helpful in reducing surgical site infections, compared with 71% of patients receiving PI (P>.05). Being recruited as an active participant in surgical site infection prevention was a positive experience for 87.2% of MO patients and 86.3% of PI patients (P=.652). Those assigned to receive PI solution preoperatively reported significantly fewer adverse events than the nasal MO group (P<.01). Preoperative nasal decolonization with either nasal PI or MO was considered somewhat or very helpful by more than two-thirds of patients.

Antibiotic prophylaxis in craniotomy: a review

The effectiveness of antibiotic prophylaxis (AP) in craniotomies has been clarified through the accumulation of evidence and increased antibiotic knowledge. This paper focuses on the use of AP in craniotomies during different historical periods and collects highly relevant evidence on this issue. This review surveys different AP guidelines and explains why cefazolin was selected by most guidelines. Recent prominent topics, including strategies to update and implement guidelines and antibiotic efficacy in postoperative meningitis and surveillance and decolonization therapies for methicillin-resistant Staphylococcus aureus, are discussed.

Does the nose know? An update on MRSA decolonization strategies

Colonization with methicillin-resistant Staphylococcus aureus (MRSA) is an important step in the pathogenesis of active infection and is a key factor in the epidemiology of MRSA infection. Decolonization of patients found to have MRSA carriage may be of value in certain patient populations, especially those undergoing elective surgery. However, the most commonly used agent for decolonization, mupirocin, comes with a considerable risk of resistance if widely employed. Recent studies of other novel agents for decolonization show promise, but further research is necessary. This review focuses on the pathogenesis from MRSA colonization to infection, identifies the risk factors for colonization, and summarizes decolonization strategies, including novel approaches that may have a role in decreasing MRSA disease burden.

Methicillin-resistant Staphylococcus aureus nasal carriage among patients receiving hemodialysis in Taiwan: prevalence rate, molecular characterization and de-colonization

BACKGROUND

Staphylococcus aureus, particularly methicillin resistant (MRSA), is a common pathogen among patients receiving hemodialysis. To evaluate nasal carriage, molecular characterization and effectiveness of decolonization of MRSA among patients receiving hemodialysis in Taiwan, we conducted this study.

METHODS

From January to June 2011, two nasal samplings with a 3-month interval were obtained from patients undergoing hemodialysis in a medical center (CGMH), and in a local hospital (YMH) and sent for detection of MRSA. For MRSA carriers, decolonization procedures were administered. All patients in CGMH were observed if MRSA infections occurred during the study period.

RESULTS

A total of 529 nasal specimens (265 from CGMH and 264 from YMH) were collected from 296 patients (161 from CGMH and 135 from YMH). 233 patients participated in both surveys. Average one-time point MRSA carriage rate was 3.8%, and the rate was up to 6.9% for those with two-time point surveys. No additional significant factor for MRSA carriage was identified. Seventy percent of the 20 colonizing MRSA isolates, though categorized as healthcare-associated strains epidemiologically, shared common molecular characteristics of the local community-associated strains. Only one of the 20 MRSA-colonized patients failed decolonization and had persistent colonization, while without any intervention, 17 (61%) of 28 patients with methicillin-sensitive S. aureus colonization in the first survey had persistent colonization of a genetically indistinguishable strain. Within the study period, two patients (1.24%) in CGMH, one with MRSA colonization (9.1%), developed MRSA infection.

CONCLUSION

A substantial proportion of patients receiving hemodialysis in Taiwan had MRSA colonization, mostly genetically community strains. Decolonization procedures may effectively eliminate MRSA colonization and might reduce subsequent MRSA infection in these patients.

Antibiotic overuse and resistance in dermatology

Antibiotics have a significant role in dermatology, treating a wide range of diseases, including acne, rosacea, inflammatory skin conditions and skin structure infections, such as cellulitis, folliculitis, carbuncles, and furuncles. Because of their consistent use, utility, and availability, antibiotics are susceptible to overuse within the medical practice, and, specific to this discussion, in the dermatologic setting. The issue of continuously increasing risk of antibiotic resistance remains an important concern to the dermatologist. The scope of this review will be to provide an overview of the common antibiotics used in the dermatologic setting with an emphasis on identifying areas of overuse, reported bacterial resistance, and discussion of clinical management aimed at decreasing antibiotic resistance.

The persistence of Staphylococcus aureus decolonization after mupirocin and topical chlorhexidine: implications for patients requiring multiple or delayed procedures

Preoperative screening and decolonization of methicillin-sensitive and methicillin-resistant Staphylococcus aureus (MSSA and MRSA, respectively) are advocated to reduce surgical site infections. We determined the rate and duration of decolonization in patients undergoing elective orthopedic surgery. Patients undergoing elective orthopedic surgery were seen in our preoperative testing program (PAT) and had their anterior nares cultured for MRSA and MSSA. All patients were treated with intranasal mupirocin and a topical chlorhexidine solution. A cohort of patients returned to PAT before a subsequent elective procedure and were recultured. All culture results and time between PAT visits were recorded, and the rates of successful initial and persistent decolonization were determined. Six hundred ten patients visited PAT 1290 times. Overall, 94 (70.1%) of 134 patients with initially MRSA- or MSSA-positive cultures remained decolonized at a mean time of 156 days (SD=140), whereas 40 patients (29.9%) were not decolonized by the time of repeat testing at a mean time of 213 days (SD=187). At repeat testing, there were 2 newly MRSA-positive and 35 newly MSSA-positive patients. Staphylococcus aureus decolonization with intranasal mupirocin and topical chlorhexidine was effective but not persistent in a significant proportion of patients. A small number of previously uncolonized patients became colonized. Staphylococcus aureus screening and decolonization protocols must be repeated before any readmission, regardless of prior colonization status.

The potential economic value of a Staphylococcus aureus vaccine among hemodialysis patients

Staphylococcus aureus infections are a substantial problem for hemodialysis patients. Several vaccine candidates are currently under development, with hemodialysis patients being one possible target population. To determine the potential economic value of an S. aureus vaccine among hemodialysis patients, we developed a Markov decision analytic computer simulation model. When S. aureus colonization prevalence was 1%, the incremental cost-effectiveness ratio (ICER) of vaccination was ≤$25,217/quality-adjusted life year (QALY). Vaccination became more cost-effective as colonization prevalence, vaccine efficacy, or vaccine protection duration increased or vaccine cost decreased. Even at 10% colonization prevalence, a 25% efficacious vaccine costing $100 prevented 29 infections, 21 infection-related hospitalizations, and 9 inpatient deaths per 1000 vaccinated HD patients. Our results suggest that an S. aureus vaccine would be cost-effective (i.e., ICERs ≤ $50,000/QALY) among hemodialysis patients over a wide range of S. aureus prevalence, vaccine costs and efficacies, and vaccine protection durations and delineate potential target parameters for such a vaccine.

Staphylococcal decolonisation: an effective strategy for prevention of infection?

Staphylococcus aureus decolonisation--treatment to eradicate staphylococcal carriage--is often considered as a measure to prevent S aureus infection. The most common approach to decolonisation has been intranasal application of mupirocin either alone or in combination with antiseptic soaps or systemic antimicrobial agents. Some data support the use of decolonisation in surgical patients colonised with S aureus, particularly in those undergoing cardiothoracic procedures. Although this intervention has been associated with low rates of postoperative S aureus infection, whether overall rates of infection are also decreased is unclear. Patients undergoing chronic haemodialysis or peritoneal dialysis might benefit from decolonisation, although repeated courses of treatment are needed, and the effects are modest. Eradication of meticillin-resistant S aureus (MRSA) carriage has generally been difficult, and the role of decolonisation as an MRSA infection control measure is uncertain. The efficacy of decolonisation of patients with community-associated MRSA has not been established, and the routine use of decolonisation of non-surgical patients is not supported by data.