Journal of Chemotherapy

ISSN: 1120-009X (Print) 1973-9478 (Online) Journal homepage:

How can you manage your patients without ‘breakpoint’? Hideharu Hagiya To cite this article: Hideharu Hagiya (2015) How can you manage your patients without ‘breakpoint’?, Journal of Chemotherapy, 27:3, 193-194, DOI: 10.1179/1973947814Y.0000000196 To link to this article:

Published online: 29 May 2014.

Submit your article to this journal

Article views: 16

View related articles

View Crossmark data

Full Terms & Conditions of access and use can be found at Download by: [Monash University Library]

Date: 15 April 2016, At: 18:27

Brief Communication

How can you manage your patients without ‘breakpoint’? Hideharu Hagiya

Downloaded by [Monash University Library] at 18:27 15 April 2016

Department of General Medicine, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Japan Choosing appropriate antibiotics is essential for the treatment of patients diagnosed with infectious diseases (IDs). This choice requires adequate understanding of the pharmacokinetics and pharmacodynamics of individual antimicrobial drugs. Breakpoints are used to define pathogen antibiotic susceptibility or resistance. In general, microbiological laboratories determine minimum inhibitory concentrations (MICs) for individual drugs, assign ‘SIR’ (sensitive, intermediate, or resistant) judgments with reference to breakpoints set by the Clinical and Laboratory Standards Institute or the European Committee on Antimicrobial Susceptibility Testing,1,2 and report these findings to clinicians. Breakpoints differ by the combination pattern of antimicrobial agents and organisms; memorizing every breakpoint is therefore impossible, even for ID specialists. Thus, breakpoints or ‘SIR’ judgments should be accompanied by MICs in working reports from microbiological laboratories. Otherwise, clinicians cannot make informed decisions on appropriate antibiotic treatment for patients. The laboratory in our medical facility reports neither breakpoints nor ‘SIR’ determinations. They report only the organisms detected and antimicrobial MICs determined by automated antibiotic resistance system for each. Table 1 shows an actual laboratory report. The report consists of only antibiotic abbreviations and MICs. This information is insufficient for most clinicians to choose appropriate antibiotic treatments. Some may erroneously believe lower MICs to indicate clinically superior antibiotics. However, MIC values cannot be directly compared between different antimicrobial agents. An enumeration of MICs is like a secret code: meaningless to most clinicians. Reporting of breakpoints must assist clinicians in choosing proper treatment by making it easy to differentiate resistance from susceptibility.

Correspondence to: H. Hagiya, Department of General Medicine, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, 2-5-1 Shikata-cho, Kitaku, Okayama 7008558, Japan. Email: [email protected]

ß 2015 Edizioni Scientifiche per l’Informazione su Farmaci e Terapia DOI 10.1179/1973947814Y.0000000196

The number of patients diagnosed with IDs is increasing in this aging society with improved access to sophisticated medical services. ID specialists alone cannot deal with the increasing number of infectious cases. As a result, clinicians are expected to engage in the treatment of ID. A gastroenterologist may treat a patient with pneumonia, a rheumatologist may treat a patient with cholangitis, a cardiologist may treat a patient with blood stream infection, and so on. Microbiological reports without breakpoints or ‘SIR’ judgments would be esoteric to them. In addition to treating patients, ID departments should offer proper information and arrange reporting systems concerning those complicating microbiological examinations for non-ID specialists. Inappropriate treatment may negatively affect patient prognosis, increase healthcare cost, and contribute to the emergence of highly resistant bacteria due to the abuse of wide-spectrum antibiotics. According to a national study, our university hospital was ranked among the top five Japanese medical facilities for carbapenem use. Proper management of IDs potentially solves social problems that many medical facilities face, including medical safety and healthcare costs. I have insisted that the microbiological laboratory should report breakpoints or ‘SIR’ judgments with or without MICs. I have repeatedly discussed this request with the ID department and our hospital laboratory. However, my opinion has been disregarded until now. I assume that reporting breakpoints or ‘SIR’ judgments is a world standard. To the best of my knowledge, our facility is the only one in Japan that does not report breakpoints or ‘SIR’ judgments. Although MIC differences within susceptible ranges do not generally matter, certain situations exist that require evaluation of MICs, e.g. patients with infective endocarditis, vancomycin administration for methicillin-resistant Staphylococcus aureus infection, etc. However, these exceptions should be managed by ID specialists. Although antimicrobials associated with resistance should not be administered

Journal of Chemotherapy








How can you manage your patients without ‘breakpoint’?

Downloaded by [Monash University Library] at 18:27 15 April 2016

Table 1 An actual example of report of antimicrobial susceptibility testing Antibiotics

MIC (mg/ml)


16 64 16 2 4 16 .16 4 .16 .16 .16 .32 #0.5 4 1 2 8 1 32 .32 4 16 1 1 8

Japanese do not understand foreign languages. Results of imaging tests are reported with comments from radiologists, and results of pathological examinations are reported with comments from pathologists. Similarly, results of MICs should be accompanied with clinical breakpoints. Without this translational step, results of antimicrobial susceptibility testing cannot be maximally utilized. Proper use of antibiotics is a difficult issue with seemingly warring goals that must be balanced: maximum effectiveness of antibiotic treatments and prevention of resistant bacteria. At the least, microbiological reports without breakpoints or ‘SIR’ judgments are an obstacle to appropriate antibiotics prescription. How can you appropriately manage your patients in our facility? Are there any medical facilities in the world where they do not refer to the ‘breakpoint’ in choosing proper antimicrobials? I would like to seek opinions or comments universally.

Disclaimer Statements

Note: Antimicrobial susceptibility testing was performed for Stenotrophomonas maltophilia. This report does not include breakpoints or SIR (sensitive, intermediate, resistant) determinations. Only antibiotic abbreviations and MICs are listed. The appropriate antibiotic treatment cannot be determined based only on the information in this insufficient report.

Contributors Only I, Hideharu Hagiya, contributed and was responsible for this article. Funding None. Conflicts of interest None to declare. Ethics approval None.

to patients at any time, such misguided prescription can be unfortunately given in our situation. To improve the treatment of IDs in clinical practice, the laboratory must report breakpoints to clinicians. Reporting breakpoints is similar to language translation. Many clinicians do not fully understand MICs, just as many


Journal of Chemotherapy




NO .


References 1 Clinical and Laboratory Standards Institute. Performance standards for antimicrobial susceptibility testing. CLSI document M100-S23. Wayne, PA: CLSI; 2013. 2 European Committee on Antimicrobial Susceptibility Testing. Breakpoint tables for interpretation of MICs and zone diameters (Version 3.0). Basel: EUCAST; 2013.

How can you manage your patients without 'breakpoint'?

How can you manage your patients without 'breakpoint'? - PDF Download Free
301KB Sizes 2 Downloads 3 Views