Posts filed under ‘Epidemiología’

Detection of MRSA in nasal swabs—marked reduction of time to report for negative reports by substituting classical manual workflow with total lab automation

European Journal of Clinical Microbiology & Infectious Diseases, September 2018 V.37 N.9 P.1745–1751

Irene Burckhardt, Susanne Horner, Florian Burckhardt & Stefan Zimmermann

In 2016, the workflow for MRSA detection in nasal swabs was changed from a classic-manual workflow to an automated workflow using total lab automation (TLA; BD Kiestra). This change entailed a reduction of the incubation time from 2 days to 20 h and reading of plates on weekdays and weekends instead of weekdays only. The workflow alteration did not include the introduction of 24/7. We wanted to follow up on the consequences for the times to report (TTR). We compared the TTR of all nasal swabs, which were sent for MRSA detection from June until August in 2015 (workflow—classic-manual) and in 2016 (workflow—automated). We calculated median TTR and interquartile ranges for the three possible reporting outcomes (negative, MRSA-known, MRSA-new) per day and workflow. A multivariable linear regression modeled the exposure variables workflow, day, and reporting outcome on TTR including interaction variables. The quantity and reasons for a TTR longer than 3 days were analyzed. During both 3-month periods, a total of 16,111 reports were issued (2015:7620; 2016:8491). The median TTR for negative reports was 48:28 (hh:mm) in 2015 and 23:58 in 2016. In the linear regression, all exposure variables had a strong and highly significant (p < 0.001) influence on the TTR. The number of reports with a TTR longer than 3 days shrank from 2418 (2015) to 60 (2016). The workflow alteration halved the median TTR for negative reports and the number of reports with a TTR longer than 3 days was reduced by 97.5%.




September 17, 2018 at 3:47 pm

Vitamin D supplementation to persistent carriers of MRSA—a randomized and placebo-controlled clinical trial

European Journal of Clinical Microbiology & Infectious Diseases, September 2018 V.37 N.9 P.1735–1744

Linda Björkhem-Bergman, Catharina Missailidis, John Karlsson-Valik, Ann Tammelin, Lena Ekström, Matteo Bottai, Ulf Hammar, Gudrun Lindh & Peter Bergman

Methicillin-resistant Staphylococcus aureus (MRSA) is resistant to all beta-lactam antibiotics and can cause severe infections that are difficult to treat. Eradication strategies with conventional antibiotics are not always effective and alternative approaches are warranted. Here, we tested the hypothesis that daily supplementation with vitamin D for 12 months would reduce MRSA carriage rates among a group of persistent carriers. This was a double-blind, placebo-controlled randomized trial with n = 65 persistent MRSA carriers with 25-hydroxy vitamin D3 (25OHD) < 75 nmol/L, who were followed up with bacterial cultures at baseline and every 3 months for 1 year. The primary endpoint was the decline in MRSA positivity during the study period. The study was conducted in two MRSA outpatient clinics at the Karolinska University Hospital, Stockholm, Sweden. In total, n = 65 persistent MRSA carriers were randomized and n = 3 were lost to follow-up. Only patients deficient in vitamin D (< 75 nmol/L) were included. Vitamin D (4000 IU) or placebo/day was administered for 12 months. The decline in MRSA positivity was equal in the vitamin D and placebo group during the study period (OR, 1.00; 95% CI, 0.97–1.03; p = 0.928) and approximately 40% in both groups were MRSA-negative after 12 months. The vitamin D group produced 103 positive cultures out of 318 cultures (32.4%) from nose, throat, and perineum over the study period, whereas the placebo group produced 135/393 positive cultures (34.0%) (Fisher’s exact test, p = 0.94). Vitamin D supplementation did not influence MRSA carriage. Thus, available data does not support vitamin D supplementation to persistent MRSA carriers.



September 17, 2018 at 3:46 pm

Comparative activity of ceftobiprole against coagulase-negative staphylococci from the BSAC Bacteraemia Surveillance Programme, 2013–2015

European Journal of Clinical Microbiology & Infectious Diseases, September 2018 V.37 N.9 P.1653–1659

Anne Santerre Henriksen, Jennifer Smart & Kamal Hamed

Coagulase-negative staphylococci (CoNS) are a significant cause of bacteraemia, the treatment of which is becoming increasingly complex due to the emergence of multidrug-resistant strains. This study aimed to evaluate the in vitro activity of ceftobiprole, an advanced-generation cephalosporin, as compared with other antimicrobial agents against CoNS from patients with bacteraemia. As part of the British Society for Antimicrobial Chemotherapy (BSAC) Bacteraemia Surveillance Programme, 650 blood isolates of CoNS were obtained from patients with bacteraemia at 74 centres throughout the UK and Ireland for the years 2013–2015. Minimum inhibitory concentrations (MICs) of ceftobiprole and other antimicrobial agents were determined using the BSAC agar dilution method. Susceptibility was assessed by European Committee on Antimicrobial Susceptibility Testing (EUCAST) criteria. The majority of the isolates (63.2%) were Staphylococcus epidermidis. Overall, methicillin resistance, as determined by oxacillin susceptibility testing, was observed in 64.2% of isolates. The MIC50/90 of ceftobiprole was 1/2 mg/L, and 100% of CoNS isolates were inhibited at the EUCAST ceftobiprole non-species-specific pharmacokinetic/pharmacodynamic breakpoint of 4 mg/L. Only one isolate was resistant to vancomycin. Overall rates of resistance to ciprofloxacin, clindamycin, erythromycin and teicoplanin were 50.5, 25.1, 68.2 and 20.9%, respectively. In S. epidermidis, resistance to oxacillin was associated with increased resistance to other antimicrobials. Ceftobiprole demonstrated in vitro activity against all CoNS species isolated from patients with bacteraemia and was active against species resistant to other antistaphylococcal antimicrobials. The collection of clinical data regarding the efficacy of ceftobiprole in treating CoNS bacteraemia is warranted.



September 17, 2018 at 3:44 pm

Tickborne Diseases — Confronting a Growing Threat

N Engl J of Medic August 23, 2018


C.I. Paules and Others

Every spring, public health officials prepare for an upsurge in vectorborne diseases. As mosquito-borne illnesses have notoriously surged in the Americas, the U.S. incidence of tickborne infections has risen insidiously, triggering heightened attention from clinicians and researchers …



September 4, 2018 at 8:34 am

The Role of One-Stage Exchange for Prosthetic Joint Infection.

Curr Rev Musculoskelet Med. July 9, 2018

Rowan FE1,2, Donaldson MJ3,4, Pietrzak JR3,4, Haddad FS3,4.

Author information

1 Department of Orthopaedic Surgery, University College London Hospital, 250 Euston Road, London, NW1 2PG, UK.

2 The Princess Grace Hospital, 42-52 Nottingham Place, Marylebone, London, W1U 5NY, UK.

3 Department of Orthopaedic Surgery, University College London Hospital, 250 Euston Road, London, NW1 2PG, UK.

4 The Princess Grace Hospital, 42-52 Nottingham Place, Marylebone, London, W1U 5NY, UK.



In an era of increasing numbers of hip and knee replacements, strategies to manage prosthetic joint infection (PJI) that are effective at infection control with good patient-reported outcomes and cost containment for health systems are needed. Interest in single-stage exchange for PJI is rising and we assess evidence from the last 5 years related to this treatment strategy.


Only five series for total knee replacement and ten series for total hip replacement have been reported in the last five years. More review articles and opinion pieces have been written. Reinfection rates in these recent studies range from 0 to 65%, but a meta-analysis and systematic review of all studies showed a reinfection rate of 7.6% (95% CI 3.4-13.1) and 8.8% (95% CI 7.2-10.6) for single-stage and two-stage revisions respectively. There is emerging evidence to support single-stage revision in the setting of significant bony deficiency and atypical PJIs such as fungal infections. Prospective randomised studies are recruiting and are necessary to guide the direction of single-stage revision selection criteria. The onus of surgical excellence in mechanical removal of implants, necrotic tissue, and biofilms lies with the arthroplasty surgeon and must remain the cornerstone of treatment. Single-stage revision may be considered the first-line treatment for all PJIs unless the organism is unknown, the patient is systemically septic, or there is a poor tissue envelope.


September 2, 2018 at 7:02 pm

Predicting lower limb periprosthetic joint infections: A review of risk factors and their classification.

World J Orthop. May 18, 2017 V.8 N.5 P.400-411.

George DA1, Drago L1, Scarponi S1, Gallazzi E1, Haddad FS1, Romano CL1.

Author information

1 David A George, Fares S Haddad, Department of Trauma and Orthopaedics, University College London Hospitals, London NW1 2BU, United Kingdom.



To undertook a systematic review to determine factors that increase a patient’s risk of developing lower limb periprosthetic joint infections (PJI).


This systematic review included full-text studies that reviewed risk factors of developing either a hip or knee PJI following a primary arthroplasty published from January 1998 to November 2016. A variety of keywords were used to identify studies through international databases referencing hip arthroplasty, knee arthroplasty, infection, and risk factors. Studies were only included if they included greater than 20 patients in their study cohort, and there was clear documentation of the statistical parameter used; specifically P-value, hazard ratio, relative risk, or/and odds ratio (OR). Furthermore a quality assessment criteria for the individual studies was undertaken to evaluate the presence of record and reporting bias.


Twenty-seven original studies reviewing risk factors relating to primary total hip and knee arthroplasty infections were included. Four studies (14.8%) reviewed PJI of the hip, 3 (11.21%) of the knee, and 20 (74.1%) reviewed both joints. Nineteen studies (70.4%) were retrospective and 8 (29.6%) prospective. Record bias was identified in the majority of studies (66.7%). The definition of PJI varied amongst the studies but there was a general consensus to define infection by previously validated methods. The most significant risks were the use of preoperative high dose steroids (OR = 21.0, 95%CI: 3.5-127.2, P < 0.001), a BMI above 50 (OR = 18.3, P < 0.001), tobacco use (OR = 12.76, 95%CI: 2.47-66.16, P = 0.017), body mass index below 20 (OR = 6.00, 95%CI: 1.2-30.9, P = 0.033), diabetes (OR = 5.47, 95%CI: 1.77-16.97, P = 0.003), and coronary artery disease (OR = 5.10, 95%CI: 1.3-19.8, P = 0.017).


We have highlighted the need for the provider to optimise modifiable risk factors, and develop strategies to limit the impact of non-modifiable factors.



September 2, 2018 at 7:00 pm

How Reliable Is the Alpha-defensin Immunoassay Test for Diagnosing Periprosthetic Joint Infection? A Prospective Study.

Clin Orthop Relat Res. February 2017 V.475 N.2 P.408-415.

Bonanzinga T1, Zahar A2, Dütsch M1, Lausmann C1, Kendoff D3, Gehrke T1.

Author information

1 HELIOS ENDO Klinik, Holstenstrasse 2, 22767, Hamburg, Germany.

2 HELIOS ENDO Klinik, Holstenstrasse 2, 22767, Hamburg, Germany.

3 HELIOS Klinik Berlin-Buch, Berlin, Germany.



A key issue in the treatment of periprosthetic joint infection (PJI) is the correct diagnosis. The main problem is lack of diagnostic tools able to diagnose a PJI with high accuracy. Alpha-defensin has been proposed as a possible solution, but in the current literature, there is a lack of independent validation.


We performed a prospective study to determine (1) what is the sensitivity, specificity, and positive and the negative predictive values of the alpha-defensin immunoassay test in diagnosing PJI; and (2) which clinical features may be responsible for false-positive and false-negative results?


Preoperative aspiration was performed in all patients presenting with a painful hip/knee arthroplasty, including both primary and revision implants. Metallosis, other inflammatory comorbidities, and previous/concomitant antibiotic therapy were not considered as exclusion criteria. An inadequate amount of synovial fluid for culture was an exclusion criterion. A total of 156 patients (65 knees, 91 hips) were included in this prospective study. At the time of revision, synovial fluid samples were taken to perform the alpha-defensin assay. During surgical débridement of tissue, samples for cultures and histologic evaluation were taken, and samples were cultured until positive or until negative at 14 days. A diagnosis of PJI was confirmed in 29 patients according to the International Consensus Group on PJI.


The sensitivity of the alpha-defensin immunoassay was 97% (95% confidence interval [CI], 92%-99%), the specificity was 97% (95% CI, 92%-99%), the positive predictive value was 88% (95% CI, 81%-92%), and the negative predictive value was 99% (95% CI, 96%-99%). Among four false-positive patients, two had metallosis and one had polyethylene wear. The false-negative case presented with a draining sinus, and intraoperative cultures were also negative.


Alpha-defensin assay appears to be a reliable test, but followup evaluation is needed to estimate longer term performance of the test. The authors believe that alpha-defensin has demonstrated itself to be sufficiently robust that PJI diagnostic criteria now should include this test. Future studies are needed to compare the differences among the diagnostic capability of the available tests, in particular when metallosis is present, because metallosis may predispose the test to a false-positive result.


Level I, diagnostic study.


September 2, 2018 at 6:58 pm

Older Posts


September 2018
« Aug    

Posts by Month

Posts by Category