Public Release: 

20 pneumococcal serotyping methods tested; concern about US healthcare quality measures


Many recently developed pneumococcal serotyping methods detect the dominant serotype in a laboratory or field sample, but several fail to detect minor serotypes, according to a study published this week in PLOS Medicine. This investigation of 20 current methods, conducted by Catherine Satzke of the Murdoch Childrens Research Institute, Royal Children's Hospital, Parkville, Victoria, Australia, and colleagues, indicates that a microarray analysis with culture amplification is a top-performing method, but a cheaper culture and latex sweep method represents a viable alternative.

About 800,000 young children, mostly living in low-income countries, die annually from pneumococcal diseases. Vaccine development requires accurate carriage studies with high sensitivity and the ability to detect multiple serotypes in individual samples. Here, in a multi-center comparative study (the PneuCarriage project), researchers used their own methods to serotype "spiked" and field samples containing combinations of Streptococcus pneumoniae bacteria. Fifteen methods detected the major serotype in the spiked samples with ?70% sensitivity, but only eight detected minor serotypes at the same threshold. For the field samples, a culture microarray method had the best overall performance (95.8% sensitivity and 93.9% Positive Predictive Value (PPV)), while a more affordable culture and latex sweep method that has been used in low-income settings showed promising performance (79.8% sensitivity and 91.4% PPV).

This study did not test all currently available serotyping methods, and assessed each method as implemented in a single, well-resourced laboratory. Nevertheless, these findings should help to guide future vaccine planning and evaluation. The authors state, "We envisage that these methods will now be applied to vaccine impact studies in low-income settings, measuring changes in carriage before and after vaccine introduction in community carriage surveys and/or in children with pneumonia, and monitoring community carriage as a sensitive indicator of herd immunity under various vaccine schedules and levels of coverage."


Research Article Funding:

This project was initially funded through the PneumoCarr Consortium (Grant 37875 funded by the Grand Challenges in Global Health Initiative which was supported by The Bill & Melinda Gates Foundation, the Foundation for the National Institutes of Health, the Wellcome Trust, and the Canadian Institutes of Health Research). The PneuCarriage project was subsequently directly funded by The Bill & Melinda Gates Foundation, Grant 52099. This project was also supported by the Murdoch Childrens Research Institute and the Victorian Government's Operational Infrastructure Support Program. The funders had no role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript; except for the specific roles of DCHB, DH and KPK as described in the author contributions. All authors have read, and confirm that they meet, ICMJE criteria for authorship.

Competing Interests:

I have read the journal's policy and the authors of the manuscript have the following competing interests: DCHB and DH are previous employees of The Bill & Melinda Gates Foundation, which provided funding for this project. KPK was employed by The Bill & Melinda Gates Foundation towards the completion of the project, but was not involved in funding the project. KPK is a member of the Editorial Board of PLOS Medicine. CS and EMD were awarded the Robert Austrian Award which is funded by Pfizer. Authors have served on advisory boards for Merck (CS, KPK, EKM), GSK (KPK, EKM), and Pfizer (KPK). Method group authors have a scientific and/or commercial interest in the performance of their methods, so blinded testing was conducted.


Satzke C, Dunne EM, Porter BD, Klugman KP, Mulholland EK, PneuCarriage project group (2015) The PneuCarriage Project: A Multi-Centre Comparative Study to Identify The Best Serotyping Methods for Examining Pneumococcal Carriage in Vaccine Evaluation Studies. PLoS Med 12(11): e1001903. doi:10.1371/journal.pmed.1001903

Author Affiliations:

Pneumococcal Research Group, Murdoch Childrens Research Institute, Royal Children's Hospital, Parkville, Victoria, Australia

Department of Microbiology and Immunology, University of Melbourne, Peter Doherty Institute for Infection and Immunity, Parkville, Victoria, Australia

Hubert Department of Global Health, Rollins School of Public Health, Emory University, Atlanta, Georgia, United States of America

Department of Infectious Disease Epidemiology, London School of Hygiene & Tropical Medicine, London, United Kingdom



Catherine Satzke
Murdoch Childrens Research Institute
Pneumococcal Research
Royal Children's Hospital
Flemington Rd
Parkville, Vic 3052
61 3 8341 6438


Medical Doctors Express Concern about Healthcare Quality Measures in the United States

As a means to improve outcomes and control costs, payers in the United States are increasingly using metrics to rate providers and health care organizations as well as to structure payment. However, payers should be careful not to mismeasure quality by prioritizing time- and cost-effectiveness over principles of patient-centeredness, evidence-based interventions, and transparency argue Barry Saver from the University of Massachusetts Medical School, United States, and colleagues in a Policy Forum article published in this week's PLOS Medicine.

The authors highlight that the Centers for Medicare and Medicaid Services (CMS), which administers national health care programs in the US, is moving towards linking 30% of Medicare reimbursements to the "quality or value" of providers' services by the end of 2016 and 50% by the end of 2018 through alternative payment models. More recently, CMS announced a goal of tying 85% of traditional fee-for-service payments to quality or value by 2016 and 90% by 2018. However, at the same time the Medicare Payment Advisory Commission cautioned that "provider-level measurement activities are accelerating without regard to the costs or benefits of an ever-increasing number of measures"

The authors argue that evidence connecting many quality measures with improved health outcomes is modest, and metrics may be chosen because they are easy to measure rather than because they are evidence-based. They also warn that with payment at stake, clinicians and organizations may be tempted to game the system by devoting disproportionate effort to patients barely on the "wrong" side of a line rather than focusing on those at highest risk.

The authors argue for a fundamental change in the approach to quality measurement and propose a set of five principals that might help shape future quality measures and ensure that they reflect meaningful health outcomes.

The authors conclude, "[s]ubstantial resources are invested in public quality efforts that suggest progress, but implementing inappropriate measures is counterproductive, undermines the professionalism of dedicated clinicians, and erodes patient trust. [Our] principles are offered to help identify what is important for health, i.e., care that matters, so we may then develop quality measures more likely to reflect and enhance the quality of care provided, while minimizing opportunities for distortions such as gaming and avoiding the opportunity costs associated with efforts to optimize surrogate endpoints."

Policy Forum


There was no source of funding for this work.

Competing Interests:

The authors have declared that no competing interests exist.


Saver BG, Martin SA, Adler RN, Candib LM, Deligiannidis KE, Golding J, et al. (2015) Care that Matters: Quality Measurement and Health Care. PLoS Med 12(11): e1001902. doi:10.1371/journal.pmed.1001902

Author Affiliations:

Department of Family Medicine and Community Health, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America

Swedish Cherry Hill Family Medicine Residency, Seattle, Washington, United States of America

Freelance Science Writer, Paxton, Massachusetts, United States of America



Barry Saver
Swedish Cherry Hill Hospital
550 16th Ave., Suite 400
United States

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