Archive for September 19, 2015

Propionibacterium acnes: from Commensal to Opportunistic Biofilm-Associated Implant Pathogen

Clinical Microbiology Reviews JUL 2014 V.28 N.3 P.419-440

Yvonne Achermann, Ellie J. C. Goldstein, Tom Coenye, and Mark E. Shirtliff

aDepartment of Microbial Pathogenesis, Dental School, University of Maryland, Baltimore, Maryland, USA

bDepartment of Microbiology and Immunology, School of Medicine, University of Maryland, Baltimore, Maryland, USA

cR. M. Alden Research Laboratory, Santa Monica, CA, USA, and David Geffen School of Medicine at UCLA, Los Angeles, California, USA

dLaboratorium voor Farmaceutische Microbiologie, Ghent University, Ghent, Belgium

Propionibacterium acnes is known primarily as a skin commensal. However, it can present as an opportunistic pathogen via bacterial seeding to cause invasive infections such as implant-associated infections.

These infections have gained more attention due to improved diagnostic procedures, such as sonication of explanted foreign materials and prolonged cultivation time of up to 14 days for periprosthetic biopsy specimens, and improved molecular methods, such as broad-range 16S rRNA gene PCR.

Implantassociated infections caused by P. acnes are most often described for shoulder prosthetic joint infections as well as cerebrovascular shunt infections, fibrosis of breast implants, and infections of cardiovascular devices. P. acnes causes disease through a number of virulence factors, such as biofilm formation.

P. acnes is highly susceptible to a wide range of antibiotics, including beta-lactams, quinolones, clindamycin, and rifampin, although resistance to clindamycin is increasing.

Treatment requires a combination of surgery and a prolonged antibiotic treatment regimen to successfully eliminate the remaining bacteria. Most authors suggest a course of 3 to 6 months of antibiotic treatment, including 2 to 6 weeks of intravenous treatment with a beta-lactam.

While recently reported data showed a good efficacy of rifampin against P. acnes biofilms, prospective, randomized, controlled studies are needed to confirm evidence for combination treatment with rifampin, as has been performed for staphylococcal implant-associated infections.




September 19, 2015 at 9:44 am

Prosthetic Joint Infection

Clinical Microbiology Reviews APR 2014 V.27 N.2 P.302-345

Aaron J. Tande and Robin Patel

aDivision of Infectious Diseases, Department of Internal Medicine, Mayo Clinic, Rochester, Minnesota, USA

bDivision of Clinical Microbiology, Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, Minnesota, USA

Prosthetic joint infection (PJI) is a tremendous burden for individual patients as well as the global health care industry.

While a small minority of joint arthroplasties will become infected, appropriate recognition and management are critical to preserve or restore adequate function and prevent excess morbidity.

In this review, we describe the reported risk factors for and clinical manifestations of PJI. We discuss the pathogenesis of PJI and the numerous microorganisms that can cause this devastating infection.

The recently proposed consensus definitions of PJI and approaches to accurate diagnosis are reviewed in detail. An overview of the treatment and prevention of this challenging condition is provided.



September 19, 2015 at 9:41 am

Disease Manifestations and Pathogenic Mechanisms of Group A Streptococcus

Clinical Microbiology Reviews APR 2014 V.27 N.2 P.264-301

Mark J. Walker, Timothy C. Barnett, Jason D. McArthur, Jason N. Cole, Christine M. Gillen, Anna Henningham, K. S. Sriprakash, Martina L. Sanderson-Smith, and Victor Nizet

aSchool of Chemistry and Molecular Biosciences and the Australian Infectious Diseases Research Centre, University of Queensland, Brisbane, QLD, Australia

bSchool of Biological Sciences and Illawarra Health and Medical Research Institute, University of Wollongong, Wollongong, NSW, Australia

cDepartment of Pediatrics and Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, California, USA

dQIMR Berghofer Medical Research Institute, Herston, Brisbane, QLD, Australia

eRady Children’s Hospital, San Diego, California, USA

Streptococcus pyogenes, also known as group A Streptococcus (GAS), causes mild human infections such as pharyngitis and impetigo and serious infections such as necrotizing fasciitis and streptococcal toxic shock syndrome.

Furthermore, repeated GAS infections may trigger autoimmune diseases, including acute poststreptococcal glomerulonephritis, acute rheumatic fever, and rheumatic heart disease.

Combined, these diseases account for over half a million deaths per year globally.

Genomic and molecular analyses have now characterized a large number of GAS virulence determinants, many of which exhibit overlap and redundancy in the processes of adhesion and colonization, innate immune resistance, and the capacity to facilitate tissue barrier degradation and spread within the human host.

This improved understanding of the contribution of individual virulence determinants to the disease process has led to the formulation of models of GAS disease progression, which may lead to better treatment and intervention strategies.

While GAS remains sensitive to all penicillins and cephalosporins, rising resistance to other antibiotics used in disease treatment is an increasing worldwide concern.

Several GAS vaccine formulations that elicit protective immunity in animal models have shown promise in nonhuman primate and early-stage human trials.

The development of a safe and efficacious commercial human vaccine for the prophylaxis of GAS disease remains a high priority.


September 19, 2015 at 9:40 am


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