Archive for September 29, 2015

Usefulness of previous methicillin-resistant Staphylococcus aureus screening results in guiding empirical therapy for S aureus bacteremia.

Can J Infect Dis Med Microbiol. 2015 Jul-Aug;26(4):201-6.

Bai AD1, Burry L2, Showler A3, Steinberg M4, Ricciuto D5, Fernandes T6, Chiu A6, Raybardhan S7, Tomlinson GA8, Bell CM9, Morris AM10.

Author information

1Faculty of Medicine, University of Ottawa, Ottawa;

2Mount Sinai Hospital, University of Toronto, Toronto; ; Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto;

3Department of Medicine, University of Toronto, Toronto; ; Division of Infectious Diseases, University of Toronto, Toronto;

4Mount Sinai Hospital, University of Toronto, Toronto;

5Department of Medicine, University of Toronto, Toronto; ; Division of Infectious Diseases, University of Toronto, Toronto; ; Lakeridge Health, Oshawa, Queen’s University, Kingston; ; Department of Medicine, Queen’s University, Kingston;

6Trillium Health Partners, Mississauga;

7North York General Hospital, Toronto, Ontario.

8Department of Medicine, University of Toronto, Toronto; ; University Health Network, Toronto, Ontario.

9Mount Sinai Hospital, University of Toronto, Toronto; ; Department of Medicine, University of Toronto, Toronto; ; University Health Network, Toronto, Ontario ; Institute for Clinical Evaluative Sciences, Toronto, Ontario.

10Mount Sinai Hospital, University of Toronto, Toronto; ; Department of Medicine, University of Toronto, Toronto; ; Division of Infectious Diseases, University of Toronto, Toronto; ; University Health Network, Toronto, Ontario.


Staphylococcus aureus bacteremia (SAB) is an important infection. Methicillin-resistant S aureus (MRSA) screening is performed on hospitalized patients for infection control purposes.


To assess the usefulness of past MRSA screening for guiding empirical antibiotic therapy for SAB.


A retrospective cohort study examined consecutive patients with confirmed SAB and previous MRSA screening swab from six academic and community hospitals between 2007 and 2010. Diagnostic test properties were calculated for MRSA screening swab for predicting methicillin resistance of SAB.


A total of 799 patients underwent MRSA screening swabs before SAB. Of the 799 patients, 95 (12%) had a positive and 704 (88%) had a negative previous MRSA screening swab. There were 150 (19%) patients with MRSA bacteremia. Overall, previous MRSA screening swabs had a positive likelihood ratio of 33 (95% CI 18 to 60) and a negative likelihood ratio of 0.45 (95% CI 0.37 to 0.54). Diagnostic accuracy differed depending on mode of acquisition (ie, community-acquired, nosocomial or health care-associated infection) (P<0.0001) and hospital (P=0.0002). At best, for health care-associated infection, prior MRSA screening swab had a positive likelihood ratio of 16 (95% CI 9 to 28) and a negative likelihood ratio of 0.27 (95% CI 0.17 to 0.41).


A negative prior MRSA screening swab cannot reliably rule out MRSA bacteremia and should not be used to guide empirical antibiotic therapy for SAB. A positive prior MRSA screening swab greatly increases likelihood of MRSA, necessitating MRSA coverage in empirical antibiotic therapy for SAB.



September 29, 2015 at 7:59 pm

Systematic Review and Meta-Analysis of the Epidemiology of Vancomycin-Intermediate and Heterogeneous Vancomycin-Intermediate Staphylococcus aureus Isolates.

PLoS One. 2015 Aug 19;10(8):e0136082. .

Zhang S1, Sun X2, Chang W2, Dai Y2, Ma X2.

Author information

1School of Medicine, Shandong University, Ji’nan, 250061, PR China.

2Department of Clinical Laboratory, Affiliated Provincial Hospital of Anhui Medical University, Hefei, 230001, PR China.



Vancomycin-intermediate Staphylococcus aureus (VISA) and heterogeneous VISA (hVISA) are associated with vancomycin treatment failure, and are becoming an increasing public health problem. Therefore, we undertook this study of 91 published studies and made subgroup comparisons of hVISA/VISA incidence in different study years, locations, and types of clinical samples. We also analyzed the genetic backgrounds of these strains.


A systematic literature review of relevant articles published in PubMed and EMBASE from January 1997 to August 2014 was conducted. We selected and assessed journal articles reporting the prevalence rates of hVISA/VISA.


The pooled prevalence of hVISA was 6.05% in 99,042 methicillin-resistant S. aureus (MRSA) strains and that of VISA was 3.01% in 68,792 MRSA strains. The prevalence of hVISA was 4.68% before 2006, 5.38% in 2006-2009, and 7.01% in 2010-2014. VISA prevalence was 2.05%, 2.63%, and 7.93%, respectively. In a subgroup analysis of different isolation locations, the prevalence of hVISA strains was 6.81% in Asia and 5.60% in Europe/America, and that of VISA was 3.42% and 2.75%, respectively. The frequencies of hVISA isolated from blood culture samples and from all clinical samples were 9.81% and 4.68%, respectively, and those of VISA were 2.00% and 3.07%, respectively. The most prevalent genotype was staphylococcal cassette chromosome mec (SCCmec) II, which accounted for 48.16% and 37.74% of hVISA and VISA, respectively. Sequence Type (ST) 239 was most prevalent.


The prevalence of hVISA/VISA has been increasing in recent years, but has been grossly underestimated. Its incidence is higher in Asia than in Europe/America. hVISA is isolated from blood culture samples more often than from other samples. These strains are highly prevalent in epidemic MRSA strains. This study clarifies the epidemiology of hVISA/VISA and indicates that the detection of these strains and the control of nosocomial infections must be strengthened.


September 29, 2015 at 7:57 pm

Bloodstream infections in intensive care unit patients: distribution and antibiotic resistance of bacteria.

Infect Drug Resist. 2015 Aug 10;8:287-96.

Russotto V1, Cortegiani A1, Graziano G2, Saporito L2, Raineri SM1, Mammina C2, Giarratano A1.

Author information

1Department of Biopathology and Medical Biotechnologies (DIBIMED), Section of Anaesthesia, Analgesia, Intensive Care and Emergency, Paolo Giaccone University Hospital, University of Palermo, Palermo, Italy.

2Department of Sciences for Health Promotion and Mother-Child Care, University of Palermo, Palermo, Italy.


Bloodstream infections (BSIs) are among the leading infections in critically ill patients. The case-fatality rate associated with BSIs in patients admitted to intensive care units (ICUs) reaches 35%-50%.

The emergence and diffusion of bacteria with resistance to antibiotics is a global health problem. Multidrug-resistant bacteria were detected in 50.7% of patients with BSIs in a recently published international observational study, with methicillin resistance detected in 48% of Staphylococcus aureus strains, carbapenem resistance detected in 69% of Acinetobacter spp., in 38% of Klebsiella pneumoniae, and in 37% of Pseudomonas spp.

Prior hospitalization and antibiotic exposure have been identified as risk factors for infections caused by resistant bacteria in different studies.

Patients with BSIs caused by resistant strains showed an increased risk of mortality, which may be explained by a higher incidence of inappropriate empirical therapy in different studies.

The molecular genetic characterization of resistant bacteria allows the understanding of the most common mechanisms underlying their resistance and the adoption of surveillance measures.

Knowledge of epidemiology, risk factors, mechanisms of resistance, and outcomes of BSIs caused by resistant bacteria may have a major influence on global management of ICU patients.

The aim of this review is to provide the clinician an update on BSIs caused by resistant bacteria in ICU patients.


September 29, 2015 at 7:55 pm

Ceftobiprole for the treatment of pneumonia: a European perspective.

Drug Des Devel Ther. 2015 Aug 18;9:4565-72.

Liapikou A1, Cillóniz C2, Torres A2.

Author information

16th Respiratory Department, Sotiria Chest Diseases Hospital, Athens, Greece.

2Pulmonology Department, Clinic Institute of Thorax (ICT), Hospital Clinic of Barcelona, Spain Insitut d’Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain.


Ceftobiprole, a new broad spectrum, parenteral cephalosporin, exhibits potent in vitro activity against a number of Gram-positive pathogens, including methicillin-resistant Staphylococcus aureus and penicillin-resistant Streptococcus pneumoniae, and Gram-negative pathogens associated with hospital-acquired pneumonia (HAP) and community-acquired pneumonia (CAP).

Ceftobiprole has demonstrated noninferiority in two large-scale pivotal studies comparing it to ceftriaxone with or without linezolid in CAP, with clinical cure rates 86.6% versus 87.4%, or ceftazidime in HAP, with clinical cure rates of 77% versus 76%, respectively.

However, ceftobiprole was inferior in the subgroup of patients undergoing mechanical ventilation. Ceftobiprole has so far demonstrated a good safety profile in preliminary studies, with similar tolerability to comparators.

The most commonly observed adverse events of ceftobiprole included headache and gastrointestinal upset.

It is the first cephalosporin monotherapy approved in the EU for the treatment of both CAP and HAP (excluding ventilator-associated pneumonia).


September 29, 2015 at 2:01 pm

Quantitative proteomic view associated with resistance to clinically important antibiotics in Gram-positive bacteria: a systematic review.

Front Microbiol. 2015 Aug 11;6:828.

Lee CR1, Lee JH1, Park KS1, Jeong BC1, Lee SH1.

Author information

1National Leading Research Laboratory of Drug Resistance Proteomics, Department of Biological Sciences, Myongji University Yongin, South Korea.


The increase of methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus (VRE) poses a worldwide and serious health threat.

Although new antibiotics, such as daptomycin and linezolid, have been developed for the treatment of infections of Gram-positive pathogens, the emergence of daptomycin-resistant and linezolid-resistant strains during therapy has now increased clinical treatment failures.

In the past few years, studies using quantitative proteomic methods have provided a considerable progress in understanding antibiotic resistance mechanisms.

In this review, to understand the resistance mechanisms to four clinically important antibiotics (methicillin, vancomycin, linezolid, and daptomycin) used in the treatment of Gram-positive pathogens, we summarize recent advances in studies on resistance mechanisms using quantitative proteomic methods, and also examine proteins playing an important role in the bacterial mechanisms of resistance to the four antibiotics.

Proteomic researches can identify proteins whose expression levels are changed in the resistance mechanism to only one antibiotic, such as LiaH in daptomycin resistance and PrsA in vancomycin resistance, and many proteins simultaneously involved in resistance mechanisms to various antibiotics.

Most of resistance-related proteins, which are simultaneously associated with resistance mechanisms to several antibiotics, play important roles in regulating bacterial envelope biogenesis, or compensating for the fitness cost of antibiotic resistance.

Therefore, proteomic data confirm that antibiotic resistance requires the fitness cost and the bacterial envelope is an important factor in antibiotic resistance.


September 29, 2015 at 1:58 pm

Cloxacillin-susceptible Staphylococcus aureus with high MIC to glycopeptides. Ever we use cloxacillin?

Rev Esp Quimioter. 2015 Sep;28 Suppl 1:25-9.

[Article in Spanish]

Morales A, Lalueza A, San Juan R, Aguado JM1.

Author information

1José María Aguado, Unidad de Enfermedades Infecciosas. Hospital Universitario 12 de Octubre, Madrid, Spain.


Staphylococcus aureus infections are yet an important cause of morbidity and mortality despite of numerous effective anti-staphylococcal antibiotics available.

There has been an increasing incidence of methicillin-resistant strains which might have led to a wider use of vancomycin. This seems to ride alongside a covert progressive increase of S. aureus vancomycin minimum inhibitory concentration.

In this way, the emergence of vancomycin-intermediate S. aureus (VISA) strains and heteroresistant-VISA has raised concern for the scarcity of alternative treatment options.

Equally alarming, though fortunately less frequent, is the emergence of vancomycin-resistant S. aureus.

Ultimately, various debate issues have arisen regarding the emergence of S. aureus strains with decreased vancomycin susceptibility, within the range still considered sensitive.

These strains have shown a different clinical behaviour regardless of vancomycin use, both in methicillin resistant and sensitive S. aureus.

The emergence of increasing vancomycin-resistance in S. aureus isolates, has stirred up the basis of therapeutic approach in staphylococcal infections.

There is yet much to explore to better define the impact of higher vancomycin minimum inhibitory concentration in staphylococcal infections.


September 29, 2015 at 1:56 pm

The Control of Methicillin-Resistant Staphylococcus aureus Blood Stream Infections in England.

Open Forum Infect Dis. 2015 Mar 12;2(2):ofv035.

Duerden B1, Fry C2, Johnson AP3, Wilcox MH4.

Author information

1Cardiff University Medical School , Heath Park , United Kingdom.

2Department of Health, Richmond House, London , United Kingdom.

3Department of Healthcare-Associated Infections and Antimicrobial Resistance , Centre for Infectious Disease Surveillance and Control , Public Health England , London , United Kingdom.

4Leeds Teaching Hospitals, University of Leeds and Public Health England , United Kingdom.


Methicillin-resistant Staphylococcus aureus (MRSA) blood stream infection (BSI) is a major healthcare burden in some but not all healthcare settings, and it is associated with 10%-20% mortality.

The introduction of mandatory reporting in England of MRSA BSI in 2001 was followed in 2004 by the setting of target reductions for all National Health Service hospitals.

The original national target of a 50% reduction in MRSA BSI was considered by many experts to be unattainable, and yet this goal has been far exceeded (∼80% reduction with rates still declining).

The transformation from endemic to sporadic MRSA BSI involved the implementation of serial national infection prevention directives, and the deployment of expert improvement teams in organizations failed to meet their improvement trajectory targets.

We describe and appraise the components of the major public health infection prevention campaign that yielded major reductions in MRSA infection.

There are important lessons and opportunities for other healthcare systems where MRSA infection remains endemic.


September 29, 2015 at 1:53 pm


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