Methicillin-resistant Infections Research Articles

A Nanocomposite Dynamic Covalent Cross-Linked Hydrogel Loaded with Fusidic Acid for Treating Antibiotic-Resistant Infected Wounds.

Methicillin-resistant Staphylococcus aureus (MRSA) is associated with high levels of morbidity and is considered a difficult-to-treat infection, often requiring nonstandard treatment regimens and antibiotics. Since over 40% of the emerging antibiotic compounds have insufficient solubility that limits their bioavailability and thus efficacy through oral or intravenous administration, it is crucial that alternative drug delivery products be developed for wound care applications. Existing effective treatments for soft tissue MRSA infections, such as fusidic acid (FA), which is typically administered orally, could also benefit from alternative routes of administration to improve local efficacy and bioavailability while reducing the required therapeutic dose. Herein, we report an antimicrobial poly(oligoethylene glycol methacrylate) (POEGMA)-based composite hydrogel loaded with fusidic acid-encapsulating self-assembled polylactic acid-b-poly(oligo(ethylene glycol) methyl ether methacrylate) (PLA-POEGMA) nanoparticles for the treatment of MRSA-infected skin wounds. The inclusion of the self-assembled nanoparticles (380 nm diameter when loaded with fusidic acid) does not alter the favorable mechanical properties and stability of the hydrogel in the context of its use as a wound dressing, while fusidic acid (FA) can be released from the hydrogel over ∼10 h via a diffusion-controlled mechanism. The antimicrobial studies demonstrate a clear zone of inhibition in vitro and a 1-2 order of magnitude inhibition of bacterial growth in vivo in an MRSA-infected full-thickness excisional murine wound model even at very low antibiotic doses. Our approach thus can both circumvent challenges in the local delivery of hydrophobic antimicrobial compounds and directly deliver antimicrobials into the wound to effectively combat methicillin-resistant infections using a fraction of the drug dose required using other clinically relevant strategies.

Is neighborhood deprivation index a risk factor for Staphylococcus aureus infections?

We assessed the association between neighborhood area deprivation index (ADI) and community-onset (co) and hospital-onset (ho) Staphylococcus aureus infection. Demographic and clinical characteristics of patients admitted to 5 adult hospitals in the mid-Atlantic between 2016 and 2018 were obtained. The association of ADI with methicillin-resistant (MRSA) and methicillin-sensitive (MSSA) S aureus infections was assessed using logistic regression models adjusting for severity of illness and days of admission. Overall, increasing ADI was associated with higher odds of co- and ho-MRSA and MSSA infection. In univariate analysis, Black race was associated with 44% greater odds of ho-MRSA infection (odds ratio [OR] 1.44; 95% CI 1.18-1.76) and Asian race (co-MRSA OR 0.355; Confidence Interval (CI) 0.240-0.525; co-MSSA OR 0.718; CI 0.557-0.928) and unknown race (co-MRSA OR 0.470; CI 0.365-0.606; co-MSSA OR 0.699; CI 0.577-0.848) was associated with lower odds of co-MSSA and co-MRSA infections. When both race and ADI were included in the model, Black race was no longer associated with ho-MRSA infections whereas Asian and unknown race remained associated with lower odds of co-MRSA and co-MSSA infection. In the multivariable logistic regression, ADI was consistently associated with increased odds of S aureus infection (co-MRSA OR 1.132; CI 1.064-1.205; co-MSSA OR 1.089; CI 1.030-1.15; ho-MRSA OR 1.29; CI 1.16-1.43: ho-MSSA OR 1.215; CI 1.096-1.346). The area deprivation index is associated with community and hospital-onset MRSA and MSSA infections.

Microbiological, Clinical and Radiological Aspects of Diabetic Foot Ulcers Infected with Methicillin-Resistant and -Sensitive Staphylococcus aureus.

Diabetic foot ulcer (DFU) is one of the most common chronic complications of diabetes. This study aimed to assess the factors with an impact on the infection of diabetic foot ulcers by methicillin-resistant S. aureus and to evaluate the influence of methicillin resistance on the frequency of osteitis (based on classic X-ray images). A total of 863 patients suffering from DFU were analyzed during the study period. Out of 201 isolated S. aureus cases, 31 (15.4%) were methicillin-resistant (MRSA). MRSA infections were associated with a higher incidence of osteitis compared to MSSA infections (p << 0.0001), both the occurrence of smaller (<50%)) and greater (>50%) inflammatory bone changes (p << 0.0001). Furthermore, MRSA occurred significantly more frequently in men than in women (p < 0.01) and more often among patients with type 2 diabetes than among patients with type 1 diabetes (p < 0.05). MRSA were isolated statistically less often in overweight patients than in patients with normal BMI (p < 0.05). DFUs infected with MRSA were significantly more frequently associated with the presence of Pseudomonas sp. and other non-fermenting bacilli than those infected with MSSA (p < 0.05). To conclude, osteitis incidence is related to MRSA infection in patients with diabetic foot ulcers; thus, patients infected by S. aureus should be closely monitored in the course of using antibiotics and treated with narrow-spectrum antibiotics.

Four temporin-derived peptides exhibit antimicrobial and antibiofilm activities against methicillin-resistant.

Temporin-GHa (GHa) was cloned from , showing a weak antimicrobial activity. In order to improve its bactericidal efficacy, GHaR6R, GHaR7R, GHaR8R and GHaR9W were designed and synthesized. Compared to the parent peptide, the GHa-derived peptides show potent antimicrobial activities against methicillin-resistant (MRSA), which is the main pathogen with high morbidity and mortality that causes various infections in humans. These peptides exert bactericidal actions on MRSA by permeabilizing the cytoplasmic membranes and damaging membrane integrity. All of the four peptides exhibit excellent stability under harsh conditions, including extreme temperature and salts. Furthermore, they inhibit the formation of biofilm and eradicate mature biofilm of MRSA. The GHa-derived peptides decrease bacterial surface hydrophobicity, autoaggregation and polysaccharide intercellular adhesion synthesis in concentration-dependent manner. Real-time quantitative reverse transcription PCR analysis revealed that the peptides downregulate the expression of adhesion genes involved in biofilm formation. Except for GHaR7R, the other three peptides have low hemolytic toxicity against human erythrocytes. In the presence of human erythrocytes, GHaR7R, GHaR8R and GHaR9W interact with MRSA preferentially. GHaR6R, GHaR8R and GHaR9W show less toxicity toward normal cells HL-7702 and hFOB1.19. These results suggest that the GHa-derived peptides may be promising antimicrobial candidates against MRSA infections.

1142. A multicenter cohort study to identify differences between methicillin-susceptible and methicillin-resistant Staphylococcus aureus infections in pediatrics in Bogotá, Colombia, 2014-2018

Abstract Background The epidemiology of methicillin-resistant (MRSA) and methicillin-susceptible (MSSA) S. aureus in pediatrics has changed in recent years. MRSA infections have been reported to be more severe than MSSA. Methods Multicenter retrospective cohort, in 6 pediatric hospitals in Bogotá, Colombia, between January 1, 2014, and December 31, 2018, 1 isolate was included for patient from the same origin. Infections were classified into: SSTI, osteoarticular, bacteremia, or pneumonia.The objective is to establish differences between clinical, laboratory, and outcomes of MSSA and MRSA infections, according to origin of the infection in a pediatric population from Bogotá, Colombia. Results 551 patients were included; 211 (38%) MRSA and 340 (62%) MSSA, in total 703 cultures. Figure 1. Some risk factors were statistically associated with MSSA: Heart disease (3.3% Vs. 0.5%) neurologic disease (5.9% vs. 2.4%), surgery in last 6 months (11% vs. 5%), use of vascular or external devices (3% vs 11%) and previous hospitalization &amp;gt;3 days (11% vs 17%) Table 2. In 84/159 (52%) cases, bacteremia was associated with osteoarticular infection (OI), 19/159 (13%) with pneumonia, 21/159 (13%) with SSTI, 14/159 (9%) with other foci, 21/159 (13%) were primary. Independently of the origin, PICU admittance was more frequent in MRSA (52% vs. 28), as well as mechanical ventilation (MV) (30% vs. 13%) and inotropic support (IS )(38% vs 17%). Of 136 osteoarticular infections, 59 (43,4%) were MRSA and 77 (56,6%) MSSA. MRSA isolates required more than 3 surgical procedures (45% vs 24%), more PICU admittance (36% vs. 12%) and IS (27% vs. 5%). Complicated pneumonia was more frequently associated to MRSA in comparison with MSSA (57% vs. 23%). In pneumonia, MRSA also was significantly associated with PICU. (74%vs 50%), MS (61%vs 32%), and VS (52% vs 27%). SSTI was not associated with greater severity or worse outcome (PICU, MV, IS) according to S. aureus susceptibility. Table 3b. Infection groups depending on the presence or not of resistance Conclusion MRSA was associated with more severe course in bacteremia, OI and pneumonia. It is interesting that some classically risk factors associated with MRSA infections were found to be related to MSSA. In general, with SSTI exception, MRSA increase risk of PICU, mechanical support and inotropic support in a pediatric population in Bogotá, Colombia. Disclosures Ivan Felipe Gutiérrez Tobar, n/a, Pfizer and MSD (Advisor or Review Panel member, Research Grant or Support, Speaker’s Bureau, Has received support from Pfizer and MSD for participation in congresses and has received conference payments from Pfizer)Pfizer and MSD (Speaker’s Bureau, Other Financial or Material Support, Has received support from Pfizer for participation in congresses) Sandra Beltran, n/a, Pfizer (Other Financial or Material Support, Has received support from Pfizer for participation in congresses)

Characterisation of antibiotic resistance, virulence, clonality and mortality in MRSA and MSSA bloodstream infections at a tertiary-level hospital in Hungary: a 6-year retrospective study

BackgroundStaphylococcus aureus bloodstream infections (BSI) cause significant morbidity and mortality due to the frequent antibiotic resistance, toxin and adhesin production of the bacterium. These characteristics differ significantly in methicillin resistant (MRSA) and methicillin sensitive S. aureus (MSSA) and also among isolates of different MRSA clones, contributing to the outcome of S. aureus bacteraemia.MethodsIn this study, all MRSA BSI isolates from Semmelweis University, Budapest, Hungary, isolated between 2011–2016 and the same number of matched MSSA (overall 306 isolates) were characterised in terms of antibiotic susceptibility, virulence genes, clonality and their association with all-cause 30-day mortality. Effect of patient related variables, such as age, gender and comorbidities were also investigated.ResultsST22-MRSA-IV and ST5-MRSA-II were the most prevalent clones in our study. SCCmec I isolates showed the highest resistance rates and SCCmec II carried most virulence genes. Infections caused by SCCmec IV isolates were associated with the highest mortality rate (42.2%), despite the similar comorbidity rates of the different patient groups. All-cause 30-day mortality was 39.9% in the MRSA and 30.7% in the MSSA group. Increased teicoplanin MIC was associated with high mortality rate. Resistance to ciprofloxacin, erythromycin and clindamycin was common in MRSA, whereas MSSA isolates were more sensitive to all antibiotics with the exception of doxycycline. All MRSA isolates were sensitive to glycopeptides and linezolid; resistance to rifampicin and sulfamethoxazole-trimethoprim was low. MRSA isolates carried more adhesion genes, superantigens were more frequent in MSSA. Panton-Valentine leukocidin was found in 2.3% of the isolates.ConclusionThis study provides insight into the clonal composition and associated mortality of BSI S. aureus isolates in Hungary. The results suggest that the outcome of the infection is determined by the antibiotic resistance, genotype of the bacterium, and patient-related factors; rather than the virulence factors carried by the bacteria.

Reconsidering Strategies for Managing Chronic Periprosthetic Joint Infection in Total Knee Arthroplasty: Using Decision Analytics to Find the Optimal Strategy Between One-Stage and Two-Stage Total Knee Revision.

Periprosthetic joint infection (PJI) following total knee arthroplasty is a growing concern, as the demand for total knee arthroplasty (TKA) expands annually. Although 2-stage revision is considered the gold standard in management, there is substantial morbidity and mortality associated with this strategy. One-stage revision is associated with lower mortality rates and better quality of life, and there has been increased interest in utilizing the 1-stage strategy. However, surgeons are faced with a difficult decision regarding which strategy to use to treat these infections, considering uncertainty with respect to eradication of infection, quality of life, and societal costs with each strategy. The purpose of the current study was to use decision analysis to determine the optimal decision for the management of PJI following TKA. An expected-value decision tree was constructed to estimate the quality-adjusted life-years (QALYs) and costs associated with 1-stage and 2-stage revision. Two decision trees were created: Decision Tree 1 was constructed for all pathogens, and Decision Tree 2 was constructed solely for difficult-to-treat infections, including methicillin-resistant infections. Values for parameters in the decision model, such as mortality rate, reinfection rate, and need for additional surgeries, were derived from the literature. Medical costs were derived from Medicare data. Sensitivity analysis determined which parameters in the decision model had the most influence on the optimal strategy. In both decision trees, the 1-stage strategy produced greater health utility while also being more cost-effective. In the Monte Carlo simulation for Decision Trees 1 and 2, 1-stage was the dominant strategy in about 85% and 69% of the trials, respectively. Sensitivity analysis showed that the reinfection and 1-year mortality rates were the most sensitive parameters influencing the optimal decision. Despite 2-stage revision being considered the current gold standard for infection eradication in patients with PJI following TKA, the optimal decision that produced the highest quality of life was 1-stage revision. These results should be considered in shared decision-making with patients who experience PJI following TKA. Economic and Decision Analysis Level IV. See Instructions for Authors for a complete description of levels of evidence.

2321. Epidemiology of Staphylococcus aureus Infections in Patients Admitted to Freestanding Pediatric Hospitals, 2009–2016

Background S. aureus causes a substantial number of pediatric infections in the United States each year, with potential for severe complications including death. Recent data suggest S. aureus infections are declining in adults, but a nationally representative and contemporary characterization of trends in pediatric S. aureus infections is lacking. Our objective was to describe recent pediatric hospitalization trends for S. aureus and associated antibiotic prescribing patterns.MethodsWe conducted a retrospective cohort study using Pediatric Health Information Systems data from 39 tertiary care freestanding children’s hospitals in the United States. All inpatient encounters for patients ages <18 hospitalized between 1/1/2009–12/31/2016 at a continuously reporting hospital were included. Analysis was limited to patients with S. aureus infection, defined as: 1) having ≥1 ICD discharge code for methicillin-resistant (MRSA) or methicillin-susceptible (MSSA) S. aureus; and 2) ≥1 anti-staphylococcal antibiotic received. Analysis for rates were per 1,000 hospital admissions, antibiotic days of therapy (DOT) per 1,000 patient-days, and trends were analyzed using Cochran-Armitage tests; significance was set at P < 0.05.ResultsFrom 2009–2016 we identified 116,152 S. aureus hospitalizations. Patients had median age 3 (interquartile range: 0–11 years); 53.7% were male, 52.5% non-Hispanic white, and 18.8% non-Hispanic African American. From 2009 to 2016, S. aureus hospitalizations declined 36% from 26.3 to 16.8 infections per 1,000 admissions (P < 0.001) (figure). MRSA infections declined 52% (14.4 in 2009 to 6.9 infections per 1,000 admissions in 2016, P < 0.001) while MSSA infections declined 17% (11.9 to 9.9 infections per 1,000 admissions, P < 0.001). DOT for anti-MRSA antibiotics declined from 38.0 to 24.5 per 1,000 patient-days.ConclusionRates of pediatric hospitalization with S. aureus infection declined substantially over time. This was largely driven by decreased rates of MRSA hospitalizations, and we observed a corresponding decline in anti-MRSA antibiotic use. Further research is needed to better understand factors driving epidemiologic changes.Figure. S. aureus hospitalization rate per 1,000 hospital admissions in 39 PHIS hospitals with continuous reporting, 2009–2016.All S. aureusinfections Disclosures R. Banerjee, Accelerate Diagnostics, Biomerieux, BioFire: Grant Investigator, Research grant and Research support. S. Patel, Merck: Grant Investigator, Grant recipient and Research grant. Pfizer: Grant Investigator, Research grant.

The combined administration of vancomycin IV, standard prophylactic antibiotics, and vancomycin powder in spinal instrumentation surgery: does the routine use affect infection rates and bacterial resistance?

Surgical site infections (SSI) poses significant risk following spinal instrumentation surgery. The 2013 North American Spine Society (NASS) Evidence-Based Clinical Guidelines found that the incidence of SSI in spine surgery ranged from 0.7-10%, with higher rates with medical comorbidities. National guidelines currently recommend first-generation cephalosporins as first line prophylaxis. Due to an increase in MRSA cases in our institution, a combined antibiotic strategy using vancomycin IV, standard prophylactic antibiotics, and vancomycin powder was implemented for all spinal instrumentation surgeries. All spinal instrumentation surgeries performed at this institution from 2013-2016 were identified. Chart review was then performed to identify the inclusion and exclusion criteria, demographic data, diagnosis, type of surgery performed, and bacterial culture results. Rates of SSI, as defined by the Center for Disease Control (CDC), were calculated and antibiotic resistance was determined. As control, SSIs were identified and reviewed from 2010, prior to the implementation of the combined strategy. One thousand and seventy four subjects were identified in the combined cohort. Mean age was 52.3 years, 540 males (50.2%), 534 females (49.8%). There were 960 primary surgeries (89.4%), 114 cases revision surgeries (10.6%). Cervical myelopathy (27.9%), lumbar stenosis (16.2%), lumbar spondylolisthesis (14.0%), and scoliosis (pediatric and adult)/deformity (13.7%) were leading diagnoses. The standard prophylactic antibiotic was cefazolin IV in 524 cases (48.8%), gentamicin IV in 526 cases (49.0%), vancomycin powder was used in 72.3% of cases. Four SSI cases out of 1,074 were identified (0.37%), 3 deep and 1 superficial, with no antibiotic resistance. In the control group, there were 11 infections of 892 cases (1.23%). There were significantly lower rates of SSI in the combined group versus control (P=0.05). The combined antibiotic strategy led to low SSI rates in this retrospective case control study. Limitations of this study include retrospective design and small sample size. A large multicenter randomized clinical trial may provide further insight in the effectiveness of this strategy. Level of evidence 3. Clinical relevance: the combined antibiotic protocol may be considered in institutions with concern for SSI and methicillin resistant infections associated with spinal instrumentation surgeries.

P-323: Staphylococcus aureus with methicillin-resistant type infections in the elderly: a real challenge for geriatricians

P-323: Staphylococcus aureus with methicillin-resistant type infections in the elderly: a real challenge for geriatricians

Staphylococcus aureus infections following knee and hip prosthesis insertion procedures.

Background Staphylococcus aureus is the most common and most important pathogen following knee and hip arthroplasty procedures. Understanding the epidemiology of invasive S. aureus infections is important to quantify this serious complication.MethodsThis nested retrospective cohort analysis included adult patients who had undergone insertion of knee or hip prostheses with clean or clean-contaminated wound class at 11 hospitals between 2003–2006. Invasive S. aureus infections, non-superficial incisional surgical site infections (SSIs) and blood stream infections (BSIs), were prospectively identified following each procedure. Prevalence rates, per 100 procedures, were estimated.Results13,719 prosthetic knee (62%) and hip (38%) insertion procedures were performed. Of 92 invasive S. aureus infections identified, SSIs were more common (80%) than SSI and BSI (10%) or BSI alone (10%). The rate of invasive S. aureus infection/100 procedures was 0.57 [95% CI: 0.43-0.73] for knee insertion and 0.83 [95% CI: 0.61-1.08] for hip insertion. More than half (53%) were methicillin-resistant. Median time-to-onset of infection was 34 and 26 days for knee and hip insertion, respectively. Infection was associated with higher National Healthcare Safety Network risk index (p ≤ 0.0001).ConclusionsPost-operative invasive S. aureus infections were rare, but difficult-to-treat methicillin-resistant infections were relatively common. Optimizing preventative efforts may greatly reduce the healthcare burden associated with S. aureus infections.

Beyond numbers: the informative patterns of immuno-staphylococcal dynamics.

To evaluate new drugs, the immune system should be considered. Here we evaluated a proof-of-concept that uncovers bacterial-leukocyte interactions. Analyzing longitudinal leukocyte data from bovines infected with either methicillin-resistant (MRSA) or methicillin-susceptible (MSSA) Staphylococcus aureus, two methods were investigated: (i) an approach that assesses lymphocytes, monocytes, or neutrophils, separately, and (ii) a method that, using dimensionless indicators (products, ratios, or combinations derived from leukocyte data), explores the dynamics of leukocyte relationships in three-dimensional (3D) space and identifies data subsets of informative value. The classic approach not always distinguished infected from non-infected cows. In contrast, the alternative approach differentiated noninfected from infected animals and distinguished early MRSA from early MSSA and late MRSA infections. Discrimination was associated with the use of dimensionless indicators. When measured in 3D space, such indicators generated a very large number of combinations, which helped detect data subsets usually unobserved, such as non-overlapping infection-negative and -positive subsets, and several disease stages. The validity of such data subsets was determined with biologically interpretable data. This graphic, pattern recognition-based information system included but did not depend on any one number or variable. Because it can detect functions (relationships that involve two or more elements), in real time, if shown reproducible, the analysis of complex host-microbial dynamics could be used to evaluate antimicrobials.

One‐stage Versus Two‐stage Exchange

Liaison: Paul Lichstein MD, MSLeaders: Thorsten Gehrke MD (International), Adolph Lombardi MD, FACS (US), Carlo RomanoMD (International), Ian Stockley MB, ChB, MD, FRCS (International)Delegates: George Babis MD, Jerzy Bialecki MD, La´szlo´ Bucsi MD, Xu Cai MD, Li Cao MD, Briande Beaubien MD, Johannes Erhardt MD, Stuart Goodman MD, PhD, FRCSC, FACS, FBSE,William Jiranek MD, Peter Keogh, David Lewallen MD, MS, Paul Manner MD, WojciechMarczynski MD, J. Bohannon Mason MD, Kevin Mulhall MB, MCh, FRCSI, Wayne PaproskyMD, Preetesh Patel MD, Francisco Piccaluga MD, Gregory Polkowski MD, Luis Pulido MD, IanStockley MBBS, ChB, FRCS, Juan Suarez MD, Fritz Thorey MD, Rashid Tikhilov MD, JobDiego Velazquez MD, Heinz Winkler MD

Use of Linezolid to Treat MRSP Bacteremia and Discospondylitis in a Dog

A 1.5 yr old male German shepherd dog was evaluated for recurrent intermittent episodes of fever and lethargy. Clinicopathologic abnormalities were suggestive of a discospondylitis at the seventh and eighth thoracic vertebrae. Blood and urine cultures yielded growth of methicillin-resistant Staphylococcus pseudintermedius (MRSP) that was resistant to all commonly used antibiotics. Extralabel antibiotic susceptibility testing demonstrated susceptibility of both blood and urine isolates to linezolid. The prescribed dose was extrapolated from pharmacokinetic (PK) studies and the isolate's plasma minimum inhibitory concentration (MIC). Linezolid was administered for 23 wk and resulted in successful resolution of bacteremia, bacteriuria, and discospondylitis. When justified, linezolid should be considered to treat methicillin-resistant infections.

Aislamientos de Staphylococcus aureus sensibles a meticilina relacionados genéticamente con el clon USA300, ¿origen de los aislamientos SARM de genotipo comunitario en Colombia?

USA300 is a genetic lineage found both in methicillin-resistant (MRSA) and methicillin-sensitive Staphylococcus aureus (MSSA) isolates. In Colombia, hospital and community MRSA infections are caused by a USA300-related community genotype MRSA (CG-MRSA) clone. The genetic origin of this clone is unknown yet.To identify and characterize methicillin-resistant (MRSA) and methicillin-sensitive S. aureus (MSSA) isolates in order to improve the information about the origin of the CG-MRSA isolates in Colombia.USA300-related MSSA isolates were detected and characterized from a study of 184 S. aureus isolates (90 MRSA and 94 MSSA) recovered from infections. The genetic relatedness of the isolates was established by means of pulsed field gel electrophoresis (PFGE), multilocus sequence typing (MLST) and protein A gene typification ( spa typing).Among 184 isolates, 27 (14.7%) showed molecular characteristics and genetic relationship with the USA300 clone, of which 18 were MRSA and nine were MSSA. All USA300-related MRSA harbored Staphylococcal cassette chromosome mec (SCC mec ) IVc (3.1.2). In the MSSA isolates, SCC mec remnants or att B duplicate sites were not detected.In Colombia, the CG-MRSA isolates probably originated in the dissemination of an USA300-related MSSA clone which later acquired SCC mec IVc.

Methicillin-sensitive Staphylococcus aureus isolates related to USA300 clone: Origin of community-genotype MRSA in Colombia?

USA300 is a genetic lineage found both in methicillin-resistant (MRSA) and methicillin-sensitive Staphylococcus aureus (MSSA) isolates. In Colombia, hospital and community MRSA infections are caused by a USA300-related community genotype MRSA (CG-MRSA) clone. The genetic origin of this clone is unknown yet. To identify and characterize methicillin-resistant (MRSA) and methicillin-sensitive S. aureus (MSSA) isolates in order to improve the information about the origin of the CG-MRSA isolates in Colombia. USA300-related MSSA isolates were detected and characterized from a study of 184 S. aureus isolates (90 MRSA and 94 MSSA) recovered from infections. The genetic relatedness of the isolates was established by means of pulsed field gel electrophoresis (PFGE), multilocus sequence typing (MLST) and protein A gene typification ( spa typing). Among 184 isolates, 27 (14.7%) showed molecular characteristics and genetic relationship with the USA300 clone, of which 18 were MRSA and nine were MSSA. All USA300-related MRSA harbored Staphylococcal cassette chromosome mec (SCC mec ) IVc (3.1.2). In the MSSA isolates, SCC mec remnants or att B duplicate sites were not detected. In Colombia, the CG-MRSA isolates probably originated in the dissemination of an USA300-related MSSA clone which later acquired SCC mec IVc.

Complete heart block in a patient with acute lymphoblastic leukaemia: teicoplanin as a possible cause and review of literature

Teicoplanin is a glycopeptide antibiotic used against documented or presumed methicillin-resistant infections. We report a 31-month-old boy with acute lymphocytic leukaemia who developed permanent complete atrioventricular block (CAVB) necessitating pacemaker insertion after receiving teicoplanin for Staphylococcus epidermidis bacteremia. Clinical assessment of the child revealed febrile neutropenia. After thorough assessment and work-up, the patient was started on teicoplanin intravenously after which he had sudden onset of bradycardia. Electrocardiography showed CAVB that eventually required permanent pacemaker insertion. Twenty-nine months from the incident, the patient is doing well. We report on a case of teicoplanin-associated CAVB in a child with acute lymphoblastic leukaemia (ALL). This is one of only two similar cases reported in the literature. Teicoplanin remains the most probable cause. The use of teicoplanin should be approached cautiously in the setting of immunosuppression. Whether VZV contributed and teicoplanin triggered remains speculative. Physicians should be aware of this possible complication.

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

BackgroundStaphylococcus 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.MethodsFrom 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.ResultsA 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.ConclusionA 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.

Patient Education as a Means to Reduce Methicillin Resistant Staph Aureus Surgical Site Infections in Patients with Known Colonization

Methicillin resistant Staph aureus (MRSA) is a frequently recognized pathogen causing surgical site infections (SSIs). Patients with MRSA colonization are known to have an increased risk of MRSA infection. Evidence based preventive measures were in place in 2009 to include chlorhexidine cloth applications pre-operatively, appropriate antibiotic selection and timing, clipping versus shaving, Staphylococcus aureus nasal screens for implant patients and, intranasal Mupirocin for patients with positive nasal screens.

Girdlestone Procedure: When and Why

Girdlestone is one of the options for treating an infected hip arthroplasty (along with isolated antibiotics, debridement, and one or two-stage exchange). The choice must be based on a list of previous considerations. RESULTS OF GIRDLESTONE: Major differences among different series are reported in literature: from 13% to 83% of patients are satisfied with the result. Healing of infection is attained in 80% to 100% of patients, but figures are worse in special subsets (rheumatoid arthritis, enterococcal and methicillin-resistant infections, or when cement is retained). Pain is reported as severe in 16% to 33% of patients, moderate in 24% to 53% and mild in 76%, while only some authors refer to "satisfactory pain relief". Up to 45% of geriatric patients are unable to walk and only 29% walk independently. The literature reports Harris Hip scores from 25 to 64. INDICATIONS FOR GIRDLESTONE: Absolute indications: non-ambulatory patients because of other problems or diseases, and impossible reimplantation (2nd-stage surgery) (unacceptable anaesthetic or surgical risk, technical difficulties, patient rejection). RELATIVE INDICATIONS: Dementia (risk of dislocation vs. severely reduced walking ability), immunocompromise (up to what degree of immune impairment do we accept to take the risk?), intravenous drug abuse (how can you prove it?).