Japanese Society Of Chemotherapy Research Articles

Fourth national Japanese antimicrobial susceptibility pattern surveillance program: Bacterial isolates from patients with complicated urinary tract infections

IntroductionAntimicrobial susceptibility patterns of bacterial pathogens isolated from patients with complicated urinary tract infections were analyzed using the national surveillance data, comprising 793 bacterial strains from eight clinically relevant species. Materials and methodsData were collected for the fourth national surveillance project from July 2020 to December 2021 by the Japanese Society of Chemotherapy, the Japanese Association for Infectious Disease, and the Japanese Society of Clinical Microbiology. Surveillance was supervised with the cooperation of 43 medical institutions throughout Japan. ResultsFluoroquinolone required a minimum inhibitory concentration (MIC) of 2–64 mg/L to inhibit the 330 tested Escherichia coli strains. The proportion of levofloxacin-resistant E. coli strains increased from 28.6% in 2008 to 29.6% in 2011, 38.5% in 2015, and 44.5% in 2021. The proportion of levofloxacin-resistant strains of Pseudomonas aeruginosa also increased from previous survey results, showing a continuing downward trend. Conversely, the proportion of levofloxacin-resistant strains of Enterococcus faecalis decreased relative to previous reports. Neither multidrug-resistant P. aeruginosa nor carbapenem-resistant Enterobacteriaceae were detected. For methicillin-resistant Staphylococcus aureus (MRSA), the proportion of vancomycin-susceptible strains (MIC of 2 μg/mL) decreased from 14.7% to 7.7%. DiscussionBacterial strains that produced extended-spectrum β-lactamase included E. coli (82/330 strains, 24.8%), Klebsiella pneumoniae (11/68 strains, 16.2%), and Proteus mirabilis (4/26 strains, 15.4%). As compared to previous surveillance reports, these strains showed an increase in proportion over the years.

Clinical Practice Guidelines for Therapeutic Drug Monitoring of Vancomycin in the Framework of Model-Informed Precision Dosing: A Consensus Review by the Japanese Society of Chemotherapy and the Japanese Society of Therapeutic Drug Monitoring.

Background: To promote model-informed precision dosing (MIPD) for vancomycin (VCM), we developed statements for therapeutic drug monitoring (TDM). Methods: Ten clinical questions were selected. The committee conducted a systematic review and meta-analysis as well as clinical studies to establish recommendations for area under the concentration-time curve (AUC)-guided dosing. Results: AUC-guided dosing tended to more strongly decrease the risk of acute kidney injury (AKI) than trough-guided dosing, and a lower risk of treatment failure was demonstrated for higher AUC/minimum inhibitory concentration (MIC) ratios (cut-off of 400). Higher AUCs (cut-off of 600 μg·h/mL) significantly increased the risk of AKI. Although Bayesian estimation with two-point measurement was recommended, the trough concentration alone may be used in patients with mild infections in whom VCM was administered with q12h. To increase the concentration on days 1–2, the routine use of a loading dose is required. TDM on day 2 before steady state is reached should be considered to optimize the dose in patients with serious infections and a high risk of AKI. Conclusions: These VCM TDM guidelines provide recommendations based on MIPD to increase treatment response while preventing adverse effects.

Clinical practice guidelines for therapeutic drug monitoring of teicoplanin: a consensus review by the Japanese Society of Chemotherapy and the Japanese Society of Therapeutic Drug Monitoring.

BackgroundOwing to its low risk of adverse effects, teicoplanin has been extensively used in patients with infections caused by MRSA. To promote the better management of patients receiving teicoplanin, we have updated the guidelines for therapeutic drug monitoring (TDM).MethodsThe guidelines were developed by a committee following the methodology handbook published by the Japanese Medical Information Distribution Service. Nine clinical questions were selected. The committee conducted a systematic review and meta-analysis to establish evidence-based recommendations for the target trough concentration (Cmin). An initial electronic database search returned 515 articles, and 97 articles qualified for a full review. Four and five studies were included for the efficacy evaluation of cut-off Cmin values of 15 and 20 mg/L, respectively.ResultsCompared with Cmin < 15 mg/L, a target Cmin value of 15–30 mg/L resulted in increased clinical efficacy in patients with non-complicated MRSA infections (OR = 2.68; 95% CI = 1.14–6.32) without an increase in adverse effects. Although there was insufficient evidence, target Cmin values of 20–40 mg/L were suggested in patients with complicated or serious MRSA infections. A 3 day loading regimen followed by maintenance treatment according to renal function was recommended to achieve the target trough concentrations. Because of the prolonged half-life of teicoplanin, measurement of the Cmin value on Day 4 before reaching steady state was recommended.ConclusionsThe new guideline recommendations indicate the target Cmin value for TDM and the dosage regimen to achieve this concentration and suggest practices for specific subpopulations.

Impact of the practical guideline on appropriate usage of antimicrobial treatments for surgical site infections in reconstructive surgery of head and neck cancer

ObjectivesIn 2016, Japanese Society of Chemotherapy and Japan Society for Surgical Infection presented the practical guideline for appropriate usage of antimicrobial agents to prevent postoperative infections. This study aims to exhibit the validity of the guideline as a series of effective strategies for prevention of surgical site infections (SSIs) during reconstructive surgery of the head and neck cancer. MethodsWe retrospectively evaluated patients who underwent head and neck reconstructive surgery with free or pedicle flaps in a single institute in Japan between July 2010 and July 2020. We evaluated the incidence of SSIs, patient backgrounds, and microbiological characteristics on the basis of antimicrobial prophylaxis recommended by the guideline. ResultsEnrolled in this study were 102 patients in our institution who underwent head and neck reconstructive surgery with free or pedicle flaps between July 2010 and July 2020. In the period between January 2018 to July 2020 after the SSI guideline was advocated (SSI guideline period), the ratio of administration of sulbactam/ampicillin (SBT/ABPC) was significantly higher (P < 0.001) and the duration of prophylactic antimicrobial treatment was significantly shorter than in the period between July 2010 to December 2017 before the SSI guideline was advocated (Pre-SSI guideline period) (P < 0.001). Incidence of SSIs were similar, even when antibiotic use was changed to be short-term single-agent administration in accordance with the practical guideline. ConclusionsAdherence to the current Japanese practical guideline on appropriate antimicrobial prophylaxis for SSIs can shorten the duration of usage of antimicrobial treatment without increasing the risk for occurrence of SSIs.

Classification of the metallo β-lactamase subtype produced by the carbapenem-resistant Pseudomonas aeruginosa isolates in Japan

IntroductionMultidrug resistant microorganisms are a serious threat to human health. Under the circumstances, a front line of antimicrobials in clinical setting may be carbapenem β-lactams (CRBP). However, emergence of CRBP resistant (CRBP-r) Gram-negative bacteria are the most alarming. CRBP-r is mainly caused to the production of β-lactamase, down and up expression of the diffusion channel and the efflux pump genes, respectively. Among them, production of metallo-β-lactamase (MBL) is a major cause of high-level of CRBP-r. MethodWe analyzed the MBL subtypes by PCR and DNA sequencing in CRBP-r Psudomonas aeruginosa in the collection of the joint program by the Japanese Association for Infectious Diseases, Japan Society for Clinical Microbiology and Japanese Society of Chemotherapy (2006–2015 in Japan). ResultsAmong 275 strains out of a total 1716 isolates, 23 (8.3%) were MBL-positive exhibiting resistant to meropenem (MEPM), imipenem, ceftazidime, cefepime, ciprofloxacin and levofloxacin without exception and the MIC of MEPM appeared over 128 μg/mL. Their MBL subtype analysis revealed that 16, 2, and 2 isolates were IMP-1, IMP-7 and VIM-2 positive, respectively, and one isolate each expressed either IMP-10, IMP-34 or IMP-41. ConclusionsThis study revealed that all the MBL-positive CRBP-r isolates were highly resistant to carbapenems dominating IMP-1 production.

JCS/JHRS 2019 guideline on non-pharmacotherapy of cardiac arrhythmias.

JCS/JHRS 2019 guideline on non-pharmacotherapy of cardiac arrhythmias.

Determinants of clinic doctors’ attitudes concerning antimicrobial prescription for patients with common colds or bronchitis: Additional analysis of a nationwide survey conducted by the Japanese Society of Chemotherapy and the Japanese Association for Infectious Diseases

BackgroundIn 2019, the Japanese Society of Chemotherapy and the Japanese Association for Infectious Diseases reported nationwide, cross-sectional questionnaire survey data investigating the clinical status of clinic doctors' attitudes to antimicrobial stewardship. This study aimed to identify factors determining clinic doctors’ attitudes concerning antimicrobial prescription for patients with a common cold or bronchitis. MethodsIn February 2018, 1500 randomly selected community-based medical clinics in Japan were sent a questionnaire. Primary and secondary endpoints were clinic doctors’ attitudes concerning antimicrobial prescription, and antimicrobial medication types prescribed for patients with a common cold or bronchitis, respectively. We used multivariable linear regression analysis to identify factors associated with primary and secondary outcomes. ResultsWe analyzed 269 of 274 responses (response rate, 18.3%). Linear regression analysis was used to identify determinants of proactive attitudes to antimicrobial prescription, including whether clinic doctors encountering patients with upper respiratory symptoms and no underlying illnesses, and diagnosed with a common cold would prescribe antimicrobial medication (β = 0.283, t = 4.279, p = 0.000); whether clinic doctors frequently experienced requests from patients (or their families) with a common cold to prescribe antimicrobial medication (β = 0.389, t = 6.133, p = 0.000), and; clinic doctors' awareness of antimicrobial stewardship in the past year (β = −0.157, t = −2.456, p = 0.015). Determinants of proactive attitudes to prescribing broader-spectrum antimicrobials for patients with a common cold included clinic doctors' attitudes concerning antimicrobial prescription (β = 0.165, t = 2.622, p = 0.009), whether the respondent was a pediatrician (β = −0.288, t = −4.583, p = 0.000), and clinic doctors’ attitudes to antimicrobial prescription (β = 0.262, t = 4.075, p = 0.000) for patients with bronchitis. ConclusionThis study identified factors among clinic doctors that determined their attitudes to antimicrobial prescription concerning patients with a common cold or bronchitis. Identification and targeting of clinic doctors who unnecessarily prescribe antimicrobial medication is urgently required to promote antimicrobial stewardship in an outpatient setting.

The third national Japanese antimicrobial susceptibility pattern surveillance program: Bacterial isolates from complicated urinary tract infection patients

The antimicrobial susceptibility patterns of bacterial pathogens isolated from patients with complicated urinary tract infections were analyzed using national surveillance data. The data consisted of 881 bacterial strains from eight clinically relevant species. The data were collected for the third national surveillance project from January 2015 to March 2016 by the Japanese Society of Chemotherapy, the Japanese Association for Infectious Disease, and the Japanese Society of Clinical Microbiology. Surveillance was undertaken with the cooperation of 41 medical institutions throughout Japan.Fluoroquinolone required a MIC90 of 2–64 mg/L to inhibit the 325 Escherichia coli strains tested and the proportion of levofloxacin resistant E. coli strains increased to 38.5% from 29.6% in 2011 and 28.6% in 2008. The proportion of levofloxacin resistant strains of Pseudomonas aeruginosa and Enterococcus faecalis decreased from previous reports and the proportion of multidrug-resistant P. aeruginosa and carbapenem-resistant Enterobacteriaceae remained low. Among methicillin-resistant Staphylococcus aureus (MRSA) strains, strains with reduced susceptibility to vancomycin (minimum inhibitory concentration, 2 μg/mL) increased to 14.7% from 5.5%.Bacterial strains that produced extended-spectrum β-lactamase included E. coli (79 of 325 strains, 24.3%), Klebsiella pneumoniae (9 of 177 strains, 7.7%), and Proteus mirabilis (6 of 55 strains, 10.9%). The proportion of extended-spectrum β-lactamase producing E. coli and K. pneumoniae strains increased from previous surveillance reports.

Non-inferior comparative study comparing one or two day antimicrobial prophylaxis after clean orthopaedic surgery (NOCOTA study): a study protocol for a cluster pseudo-randomized controlled trial comparing duration of antibiotic prophylaxis

BackgroundAntimicrobial prophylaxis (AMP) is one of the most important measures for preventing surgical site infections (SSIs); however, controversies remain regarding its adequate duration. Although the World Health Organization and the Center for Disease Control and Prevention do not recommend additional AMP after closure, the American Society of Health-System Pharmacists and the Musculoskeletal Infection Society permit the use of postoperative AMP, but recommend discontinuation within 24 h. Similarly, the Japanese Society of Chemotherapy and the Japan Society for Surgical Infection also permit AMP within 24–48 h after various orthopaedic procedures. In these guidelines, recommendations regarding AMP duration were weak due to a relative lack of evidence, and currently, there is no high-quality evidence comparing AMP use within 24 h versus 24–48 h regarding orthopaedic procedures. Urinary tract infection (UTI) and respiratory tract infection (RTI) are also important health care-associated infections (HAIs) faced after surgery. Although AMP duration may affect these HAIs, its effects have not been well evaluated.MethodsWe have organized a multicenter, prospective, cluster pseudo-randomized controlled trial to examine the non-inferiority of shorter AMP duration (within 24 h) against longer duration (24–48 h) in preventing postoperative HAIs. Participating facilities will be divided into two groups. In Group 24, AMP will be discontinued within 24 h after surgery. In Group 48, AMP will be discontinued within 24–48 h after surgery. The group allocation will be switched every 2 months until the targeted recruitment (500 participants per group) is met.The primary outcome will be the cumulative incidence of all HAIs (SSI, UTI, RTI, and other infectious diseases), which require antibiotic therapies within 30 days after surgery. In addition to mortality and cardiovascular events, prolonged hospitalization (> 30 days) and the rate of antibiotic resistance rate of SSI pathogens will also be evaluated. Outcomes will be evaluated within 30–180 days after surgery in person by the surgeon, by mail, or by telephone survey. Data will be analyzed by a statistician not engaged in data collection.DiscussionThis study may provide valuable information for developing future recommendations for adequate AMP duration after clean orthopaedic surgery.Trial registrationUMIN000030929, registered January 22, 2018.

Essential human resources for antimicrobial stewardship teams in Japan: Estimates from a nationwide survey conducted by the Japanese Society of Chemotherapy

Implementation of antimicrobial stewardship programs (ASPs) with multidisciplinary antimicrobial stewardship teams (ASTs) is critical for appropriate antimicrobial use at healthcare facilities. Although the Japanese medical reimbursement system was revised to allow fees for ASP implementation, several concerns remain, including understaffing and enforcement of the recommendations on ASTs and ASPs in practice. Furthermore, there are no recommendations on full-time equivalents (FTEs) of the core members in ASTs in Japan. This committee report presents our recommendations on ASTs based on an analysis of the nationwide survey on implemented ASPs and staff FTEs at 1358 healthcare facilities conducted by the Japanese Society of Chemotherapy. Our report provides a directive for structural and financial support of ASTs and should aid in planning for the enhancement of AST practices and the organization of new ASTs.

The first nationwide survey of antimicrobial stewardship programs conducted by the Japanese Society of Chemotherapy.

The first nationwide survey of antimicrobial stewardship programs conducted by the Japanese Society of Chemotherapy.

JAID/JSC Guidelines for the Treatment of Respiratory Infectious Diseases: The Japanese Association for Infectious Diseases/Japanese Society of Chemotherapy - The JAID/JSC Guide to Clinical Management of Infectious Disease/Guideline-preparing Committee Respiratory Infectious Disease WG.

The Japanese Association for Infectious Diseases (JAID) and Japanese Society of Chemotherapy (JSC) announced the “Guide for the Use of Antimicrobial Drugs” in 2001 and the “Guidelines for the Use of Antimicrobial Drugs” in 2005. Subsequently, the “The JAID/JSC guide to clinical management of infectious diseases 2011” was published. With its revision, guidelines were newly prepared.

Japanese nationwide surveillance in 2011 of antibacterial susceptibility patterns of clinical isolates from complicated urinarytract infection cases.

To investigate antimicrobial susceptibility patterns of various bacterial pathogens isolated from complicated urinary tract infection (UTI) cases, the Japanese Society of Chemotherapy, the Japanese Association of Infectious Disease, and the Japanese Society of Clinical Microbiology conducted the second nationwide surveillance from January to September 2011. With the cooperation of 42 medical institutions throughout Japan, 1036 strains belonging to 8 clinically relevant bacterial species were collected. Among methicillin-resistant Staphylococcus aureus (MRSA) strain, the vancomycin (VCM) MIC for 5.5% (3/55) of the strains was 2 μg/mL. Ampicillin, VCM, and linezolid were relatively active against 209 Enterococcus faecalis strains. The proportion of fluoroquinolone (FQ)-resistant strains was >20%. The MIC90 of FQs against the 382 Escherichia coli strains was 2-64 mg/L and the proportion resistant to FQs was approximately 30%. However, susceptibility of E. coli to sitafloxacin was still high (MIC90 = 2 mg/L). Fifty-eight (15.2%) of 382 E. coli, 6 (4.5%) of 132 Klebsiella pneumoniae, 1 (2.4%) of 41 Klebsiella oxytoca and 4 (6.8%) of 59 Proteus mirabilis strains were suspected of producing extended-spectrum beta-lactamase. Of 93 Pseudomonas aeruginosa strains, the proportions resistant to imipenem, amikacin, and ciprofloxacin were 21.5%, 4.3%, and 20.4%, respectively. Four strains (4.3%) were found to be multidrug-resistant. In complicated UTI cases, all of MRSA and E. faecalis were susceptible to all anti-MRSA agents. Sitafloxacin was active against other FQ-resistant E. coli strains. The isolation of extended-spectrum beta-lactamase-producing and multidrug-resistant strains increased.

Clinical Study of Acute Uncomplicated Cystitis

Escherichia coli is the most commonly isolated bacterium in urinary tract infections, especially in acute uncomplicated cystitis. It is reported that fluoroquinolone-resistant E. coli is increasing. However, according to the guidelines for antimicrobial use published by the Japanese Associations for Infectious Diseases (JAID) and the Japanese Society of Chemotherapy (JSC) in 2014, the first line antimicrobial regimen for the treatment of acute uncomplicated cystitis is a 3-day regimen with fluoroquinolone. We analyzed the causative bacteria and clinical efficacy of antimicrobial treatment in acute uncomplicated cystitis cases at our institute. Patients diagnosed as having acute uncomplicated cystitis who had ≥ 10(4) colony-forming units/mL of bacteria in their midstream urine in our outpatient clinic between 2012 and 2013 were enrolled in this study. We analyzed their clinical data retrospectively. From 173 patients, 212 strains were isolated. Of these, 135 (63.7%) were E. coli, including 15 strains (11.1%) that were levofloxacin resistant. One hundred twenty-three patients (63.7%) were treated with cephalosporin, and 46 patients (26.6%) were treated with fluoroquinolone. In all, 140 patients (80.9%) visited the outpatient clinic for an average of 8.4 days after their treatment. For 130 patients (92.6%), the clinical outcomes of antimicrobial treatment were judged as effective. The clinical outcomes were effective in 92.1% of the patients with cephalosporin treatment and in 97.1% of those with fluoroquinolone treatment. Only one patient who had levofloxacin-resistant E. coli in her urine was treated with fluoroquinolone. The clinical outcome was effective. Of the E. coli isolated from acute uncomplicated cystitis patients, 11.1% were levofloxacin-resistant strains. However, the clinical efficacy of antimicrobial treatment was relatively high (92.9%) in this study. The antimicrobial treatment for acute uncomplicated cystitis recommended by the guidelines published by the JAID and JSC was effective in the current situation.

P2.081 Antimicrobial Susceptibilities of Neisseria Gonorrhoeae Strains from Male Urethritis in Japan -the First National Surveillance

BackgroundNeisseria gonorrhoeae is one of the most important pathogens causing sexually transmitted infection. Resistant N. gonorrhoeae trains against several antimicrobials are increasing worldwide.PurposeIn this study, the trends of antimicrobial susceptibilities...

P1.017 Unique Activity of Sitafloxacin, One of Newer Fluoroquinolones, Against Ciprofloxacin-Resistant N. Gonorrhoeae

BackgroundFluoroquinolone-resistance in Neisseria gonorrhoeae is spreading in the world and almost 80% of N. gonorrhoeae strains are resistant to fluoroquinolones in Japan. It is known that the resistance to fluoroquinolones...

P2.085 The Current Antimicrobial Susceptibility in Chlamydia Trachomatis in Japan from the Nationwide Surveillance

Chlamydia trachomatis is one of the principal pathogens for non-gonococcal urethritis. There have been a few studies about novel resistant strains isolated from the patients with genital chlamydial infection. However,...

ゲンタマイシン硫酸塩注射液の使用状況に関する アンケート調査結果

Unlike what has been approved overseas, only a low dose is approved in Japan for the use of Gentamicin Sulfate Injection (hereinafter referred to as GM Injection). A change in dose and administration was requested to the Evaluation Committee on Unapproved or Off-labeled Drugs with High Medical Needs. As a consequence, high-dose GM Injection began to be developed in Japan. In order to assess the current use of GM Injection, a questionnaire survey was conducted among infectious disease specialists certified by the Japanese Association for Infectious Diseases, and physicians certified as specialists/instructors of antibiotic chemical treatment by the Japanese Society of Chemotherapy. Valid responses were obtained from as many as 38.0% of questionnaire recipients (719/1891 physicians). About 30% of the respondents used GM Injection in the year 2011. Major indications for adult patients included sepsis and infective endocarditis, and bacterial strains mainly included Pseudomonas aeruginosa, Staphylococcus, Enterococcus and Streptococcus species. Some diseases and bacterial strains domestically unapproved as indications were also treated with GM Injection. GM Injection is administered mainly as an intravenous infusion, usually once daily, which is not approved in Japan. Some physicians administered a fixed dose of GM (120 mg/day or less), not more than the upper limit approved in Japan. The majority of physicians, however, adopted a dosage of 3-5 mg/kgy/day, the standard dosage approved overseas. Physicians who implemented TDM outnumbered those who did not. The target blood level when administering 2-3 times a day was mostly 2 microg/mL or less as the trough level, and 4-10 microg/mL as the peak level. In particular, GM Injection was concurrently administered with other injectable antimicrobial agents to treat sepsis or infective endocarditis mainly in the following combinations: with penicillins or carbapenems for sepsis: with penicillins for infective endocarditis. Renal impairment was the most common adverse reaction requiring special care to be reported by the respondents. The survey revealed the current status of use, which is that GM Injection is used at the dose and administration approved in Japan, and that high-dose GM Injection, equivalent to the dosage approved overseas, is also used by quite a few physicians. The current use supports the request submitted to the Evaluation Committee on Unapproved or Off-labeled Drugs with High Medical Needs. Therefore, the same dosage that is approved overseas is recommended to be approved as soon as possible in Japan.

Nationwide surveillance of bacterial respiratory pathogens conducted by the Surveillance Committee of Japanese Society of Chemotherapy, Japanese Association for Infectious Diseases, and Japanese Society for Clinical Microbiology in 2009: general view of the pathogens’ antibacterial susceptibility

For the purpose of nationwide surveillance of antimicrobial susceptibility of bacterial respiratory pathogens from patients in Japan, the Japanese Society of Chemotherapy (JSC) started a survey in 2006. From 2009, JSC continued the survey in collaboration with the Japanese Association for Infectious Diseases and the Japanese Society for Clinical Microbiology. The fourth-year survey was conducted during the period from January and April 2009 by the three societies. A total of 684 strains were collected from clinical specimens obtained from well-diagnosed adult patients with respiratory tract infections. Susceptibility testing was evaluable with 635 strains (130 Staphylococcus aureus, 127 Streptococcus pneumoniae, 4 Streptococcus pyogenes, 123 Haemophilus influenzae, 70 Moraxella catarrhalis, 78 Klebsiella pneumoniae, and 103 Pseudomonas aeruginosa). A maximum of 45 antibacterial agents including 26 β-lactams (four penicillins, three penicillins in combination with β-lactamase inhibitors, four oral cephems, eight parenteral cephems, one monobactam, five carbapenems, and one penem), four aminoglycosides, four macrolides (including ketolide), one lincosamide, one tetracycline, two glycopeptides, six fluoroquinolones, and one oxazolidinone were used for the study. Analysis was conducted at the central reference laboratory according to the method recommended by the Clinical and Laboratory Standard Institute (CLSI). Incidence of methicillin-resistant S. aureus (MRSA) was as high as 58.5 %, and that of penicillin-intermediate and penicillin-resistant S. pneumoniae (PISP and PRSP) was 6.3 % and 0.0 %, respectively. Among H. influenzae, 21.1 % of them were found to be β-lactamase-non-producing ampicillin (ABPC)-intermediately resistant (BLNAI), 18.7 % to be β-lactamase-non-producing ABPC-resistant (BLNAR), and 5.7 % to be β-lactamase-producing ABPC-resistant (BLPAR) strains. A high frequency (76.5 %) of β-lactamase-producing strains has been suspected in Moraxella catarrhalis isolates. Four (3.2 %) extended-spectrum β-lactamase-producing K. pneumoniae were found among 126 strains. Four isolates (2.5 %) of P. aeruginosa were found to be metallo-β-lactamase-producing strains, including three (1.9 %) suspected multi-drug resistant strains showing resistance against imipenem, amikacin, and ciprofloxacin. Continuous national surveillance of the antimicrobial susceptibility of respiratory pathogens is crucial to monitor changing patterns of susceptibility and to be able to update treatment recommendations on a regular basis.

A report from the committee on microbroth dilution antimicrobial susceptibility testing

In 1968, the Japanese Society of Chemotherapy (JSC) established an agar dilution method for MIC determinations of aerobic bacteria [1]. In 1979, the JSC established an agar dilution method for MIC determinations of anaerobic bacteria. Furthermore, a revision of the agar dilution standard was made in 1980, and this served as the standard method for MIC determinations for an extensive period of time in Japan. In 1990, the committee established a standard microbroth dilution method for MIC determinations. This method was modified in 1992 for fastidious aerobic and anaerobic bacteria [2]. In the development of standards for antimicrobial susceptibility testing, there has been a movement to incorporate pharmacologic as well as clinical considerations with respect to in vitro antimicrobial susceptibility interpretations. This trend reflects the need to respond to the emergence and spread of resistant microorganisms as well as a greater understanding of pharmacokinetics and pharmacodynamics and how it relates to improved patient outcome. The Clinical Laboratory Standards Institute (CLSI) and the European Committee on Antimicrobial Susceptibility (EUCAST) are among the professional organizations that proactively revise antimicrobial susceptibility testing on a regular basis. JSC has also been revising its standards. In 2007, the agar dilution method was revised. After the exclusion of selected organisms from the CLSI agar dilution standard, this method was adopted by the JSC [3]. With respect to revising the standard method for microbroth dilution antimicrobial susceptibility testing, a committee chaired by Keizo Yamaguchi was formed in January 2008. The subcommittee’s first task was to critically examine the methods for the antimicrobial susceptibility testing of Haemophilus influenzae. Although JSC and CLSI microbroth dilution methods both use a Mueller– Hinton base, the supplements differ. This difference had raised concerns among some Japanese clinical microbiology professionals that there were many issues with the CLSI method with respect to reported difficulties in measuring endpoints and the poor growth of some strains. Our first action was to send questionnaires to the members of the JSC and the Japanese Society for Clinical Microbiology to better understand the technical problems experienced in clinical microbiology laboratories regarding microbroth dilution testing of H. influenzae. From the responses to the questionnaire, it was clear that a major problem in routine testing was the poor growth of Members of the Microdilution Susceptibility Standards Committee: committee chairperson: Keizo Yamaguchi, committee members: Yoichi Hirakata, Intetsu Kobayashi, Masanari Ikedo, Akira Ohno.