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A 67-year-old man with a pulmonary cavity was admitted to our hospital. Mycobacterial culture of the bronchoalveolar lavage fluid sample obtained from the right upper pulmonary lesion tested positive for mycobacterium, and sequencing of the 16S rRNA genes, hsp65, and rpoB revealed that the cultured mycobacterium was Mycobacterium parascrofulaceum. Treatment with antimycobacterial agents was ineffective, and repeated culturing of bronchoscopic specimens revealed that the specimens were positive for Aspergillus fumigatus. Combination treatment of antimycobacterial agents and voriconazole improved the lung lesion. This is the first report of a patient with pulmonary M. parascrofulaceum infection complicated with chronic progressive pulmonary aspergillosis.

Recent studies have demonstrated that flavonoid glucuronides can be deconjugated to the active form aglycone by β-glucuronidase-expressing macrophages. Keigairengyoto (KRT) is a flavonoid-rich traditional Japanese medicine reported to enhance bacterial clearance through immune modulation. Our aims are to examine the pharmacokinetics of KRT flavonoids and to identify active flavonoids contributing to the adjuvant effects of KRT. KRT was evaluated at pharmacokinetic analysis to quantify absorbed flavonoids, and cutaneous infection assay induced in mice by inoculation of Staphylococcus aureus . Preventive or therapeutic KRT administration reduced the number of bacteria in the infection site as well as macroscopic and microscopic lesion scores with efficacies similar to antibiotics. Pharmacokinetic study revealed low plasma levels of flavonoid aglycones after KRT administration; however, plasma concentrations were enhanced markedly by β-glucuronidase treatment, with baicalein the most abundant ( C max , 1.32 µg/mL). In random screening assays, flavonoids such as bacalein, genistein, and apigenin enhanced bacteria phagocytosis by macrophages. Glucuronide bacalin was converted to aglycone baicalein by incubation with living macrophages, macrophage lysate, or skin homogenate. Taken together, the adjuvant effect of KRT may be due to some blood-absorbed flavonoids which enhance macrophage functions in host defense. Flavonoid-rich KRT may be a beneficial treatment for infectious skin inflammation., Competing Interests: I have read the journal’s policy and the authors of this manuscript have the following competing interests: Takashi Matsumoto, Atsushi Kaneko, Junichi Koseki, and Yosuke Matsubara are employees of Tsumura & Co., Setsuya Aiba and Kenshi Yamasaki were funded by Tsumura & Co.

A study was conducted of the 1,225 Pseudomonas aeruginosa strains that were isolated at 20 medical institutions in the Kinki district between 2011 and 2013 to determine their antimicrobial susceptibility and to characterize the strains of multidrug-resistant Pseudomonas aeruginosa (MDRP) and the metallo-β-lactamase (MBL) -producing strains. The MIC50/MIC90 values (μg/mL) of the various antimicrobial agents were as follows: imipenem, 2/>8; meropenem, 1/>8; doripenem, 0.5/8; biapenem, 1/>8; tazobactam/piperacillin, 8/>64; piperacillin, 8/>64; sulbactam/cefoperazone, 8/64; cefepime, 4/16; cefozopran, 2/>16; aztreonam, 8/>16; amikacin, 4/16; levofloxacin, 1/>4; and ciprofloxacin, 0.25/>2. From the viewpoint of the annual changes in the susceptibility rates (according to the CLSI guidelines [M100-S22]), the susceptibility to tazobactam/piperacillin, piperacillin, cefepime, cefozopran and aztreonam decreased in 2013. On the other hand, two antimicrobial agents showed high susceptibility rates each year; amikacin (94.0-95.6%) showed the highest rate, followed by doripenem (80.3-82.6%). With the exception of amikacin, there were substantial inter-institutional differences in antimicrobial susceptibility. In comparison to the previous CLSI guidelines (M100-S21), the new CLSI guidelines (M100-S22) on the use of carbapenems and penicillins show that the MIC80 has been affected. The MDRP detection rates in 2011, 2012 and 2013 were 1.8% (8 strains), 1.8% (8 strains), and 2.8% (10 strains), respectively. The MBL detection rates were as follows: bla(VIM-2), 0.2% (1 strain) in 2011; bla(IMP-1), 0.9% (4 strains) in 2012, and 1.7% (6 strains, including bla(IMP-1) [3 strains], bla(IMP-2) [2 strains] and bla(VIM-2) [1 strain]) in 2013.

Background: Pneumonia is now the third leading cause of death in Japan, and the number of patients with pneumonia is expected to increase with the progression of aging of the country. Higher dosage of antibiotics has recently been used, and high-dose doripenem (DRPM; 3 g daily) was approved for use in Japan in April 2011. However, there is a lack of data regarding the efficacy and safety of high-dose DRPM in Japan. This study prospectively assessed the clinical efficacy and safety of high-dose DRPM in Japanese patients with refractory pneumonia., Methods: This study was performed at University of Occupational and Environmental Health, Japan and affiliated hospitals. The efficacy and safety of DRPM in patients with pneumonia treated with 3 g daily of DRPM, including those in whom DRPM dosage was increased from 1.5 g to 3 g daily, were evaluated., Results: The safety evaluations included 56 patients, and the efficacy was evaluated in 51 patients. DRPM (3 g daily) treatment showed the response rate of 92.2% (47/51). Adverse effects of DRPM (3 g daily) were observed in 11 of 56 patients (19.7%), and all of these patients improved after DRPM cessation. Two patients had to stop DRPM administration due to elevated aminotransferase levels. The efficacy of DRPM in patients with pneumonia in whom DRPM was increased from 1.5 g daily to 3 g daily was 84.6% (11/13)., Conclusions: High-dose DRPM (3 g daily) treatment is effective and relatively safe in Japanese patients with pneumonia., (Copyright © 2015. Published by Elsevier Ltd.)

A 23-year-old Japanese woman was admitted to A hospital due to pneumonia. IgM for Mycoplasma pneumoniae was positive, and the patient was treated with imipenem/cilastatin, clindamycin, pazufloxacin and minocycline. However, both the chest radiological findings and the symptoms became exacerbated, and she was therefore transferred to our hospital. The bronchoalveolar lavage fluid was obtained, and a 16S rRNA gene sequencing analysis revealed a monobacterial infection of Mycoplasma pneumoniae. Therefore, corticosteroid treatment in addition to minocycline was administered, and the patients symptoms, laboratory data and chest radiographs improved. Corticosteroid therapy may therefore be considered for patients with refractory M. pneumoniae pneumonia.

Background: An increasing incidence of extended-spectrum β-lactamase (ESBL-) producing Escherihia Coli poses a difficult problem for clinicians to establish an optimal strategy for the effective antibiotic treatment of urinary tract infections (UTI)., Methods: (1) Fosfomycin/minocycline (FOM/MINO) or rifampicin/sulfamethoxazole-trimethoprim (RFP/ST) combinations and (2) levofloxacin (LVFX) alone were used as an internal medication, and (3) cefoperazone/sulbactam (CPZ/SBT) and (4) meropenem (MEPM) were administered through intravenous injection. The selection of antibiotics was done empirically, according to the history and severity of illness and urinary findings, and the presence of comobidities. The efficacy of the treatment was determined by the absence of any pathogenic bacteria from a urinary culture after treatment., Results: ESBL-producing and LVFX resistant non-ESBL producing E. coli were detected by an initial urinary culture in 33 and 10%, respectively, of the specimens before treatment. All the ESBL-producing E. Coli colonies were resistant against LVFX. The efficacy of the treatment was 9/11 (82%) in the FOM/MINO-RFP/ST group, 9/14 (64%) in the LVFX group, 9/16 (56%) in the CPZ/SBT group, and 19/27 (70%) in the MEPM group. In the FOM/MINO・RFP/ST group, ESBL-producing E. Coli were detected in the urine before treatment in 5 out of 16 patients and those E. coli disappeared after treatment in all 5 patients. In the LVFX group, the drug was changed to MEPM in 6 out of 15 patients soon after the presence of ESBL-producing/LVFX resistant E. Coli was identified by a urinary culture. In the CPZ/SBT group, ESBL-producing and/or LVFX-resistant E. coli disappeared in 4 out of 6 cases, while they were newly found in post-treatment urine cultures in 2 patients. In the MEPM group, 15 out of 28 patients initially had ESBL-producing/LVFX resistant E. Coli and those drug-resistant E. Coli disappeared from their urine after treatment in all patients. The drug susceptibility test of the urinary culture from all the patients with UTI showed CPZ/SBT-resistant colonies to be found in 19 out of 32 specimens, while AMPC/CVA-resistant ones were found in 9 out of 32 of ESBL-producing E. Coli., Conclusions: Our present study demonstrates that FOM/MINO or ST combinations were effective in the treatment of ESBL-producing E. Coli in mild cases of UTI and MEPM in severe cases. When using β-lactam/β-lactamase inhibitor combinations, the effect should be ascertained by examining post-treatment urinary specimens, because of the presence of ESBL-producing E. Coli strains which are resistant to those antibiotics.

Introduction: Pneumonia is the third leading cause of mortality in Japan. In 2011, the use of meropenem (MEPM) at 3 g daily was approved to treat refractory infections in Japan. However, little has been reported on the clinical efficacy and safety of this regimen in Japanese patients with refractory infections., Objectives: This study prospectively assessed the clinical efficacy and safety of MEPM (3 g daily) in Japanese patients with refractory pneumonia and/or intrapleural infections., Methods: This study was performed at our university hospital and affiliated hospitals. The plasma concentrations of MEPM before and one and four hours after MEPM administration were also evaluated., Results: A total of 48 patients were enrolled for the efficacy and safety evaluations. The response rate to MEPM (3 g daily) treatment was 90.9% (40/44). Adverse drug reactions were observed in 17 of the 48 patients (20.8%), and all improved after the cessation of MEPM. The plasma MEPM concentration one hour after administering 1 g of MEPM was 44.9 ± 12.0 μg/ml. A pharmacokinetic analysis revealed that the percentage of time above the MIC/24 h for an MIC of 4 μg/ml or 8 μg/ml was more than 50% in 12 of 13 (92%) and in nine of the 13 patients (69%), respectively, indicating sufficient efficacy of 3 g daily of MEPM., Conclusion: Treatment with MEPM (3 g daily) in Japanese patients with refractory pneumonia and/or intrapleural infections is effective, with sufficient plasma concentrations of MEPM, and the treatment has a relatively good safety profile., (Copyright © 2014 Japanese Society of Chemotherapy and The Japanese Association for Infectious Diseases. Published by Elsevier Ltd. All rights reserved.)

Azithromycin (AZM) is one of 15-membered rings macrolide antibiotics with wide spectrum of antimicrobial efficacy for Gram-positive and -negative bacteria and also atypical bacteria. So far, there had been no reports of the prospective studies evaluating efficacy and safety of AZM infusion in patients with mild or moderate community-acquired pneumonia (CAP). This study was conducted to evaluate prospectively the efficacy and safety of AZM in patients with mild or moderate CAP. AZM 500 mg was intravenously administered once daily, and the clinical efficacy were evaluated by clinical symptoms, peripheral blood laboratory findings and chest X-rays. Sixty-four patients were firstly registered, and eventually 61 and 62 patients were enrolled for the evaluation of clinical efficacy and safety of AZM, respectively. The efficacy of AZM in 61 patients evaluated was 88.5%. In addition, the efficacies of AZM in each pneumonia severity index by A-DROP system by the Japanese Respiratory Society (JRS) guideline in CAP were 85.2% in mild and 91.2% in moderate. Furthermore, the efficacy of AZM in each differentiation between suspicion of bacterial pneumonia and that of atypical pneumonia by JRS guideline in CAP were 91.7% in suspicion of atypical pneumonia, and its efficacy was high than that of bacterial pneumonia. Nineteen patients (20 cases; 15 with liver dysfunction, 4 with diarrhea, 1 with vascular pain) out of 62 patients were reported to have possible adverse effects of AZM. All of the patients with these adverse effects demonstrated mild dysfunction and continued AZM treatment, and these dysfunctions normalized soon after cessation of AZM. In conclusion, AZM is effective drug for patients with mild or moderate CAP, and we believe that it may be one of effective choice in the treatment of CAP patients who need hospitalization.

Levofloxacin (LVFX) is one of respiratory quinolones with wide spectrum of antimicrobial efficacy for Gram-positive and -negative bacteria and also atypical bacteria, and 500 mg of intravenous LVFX infusion has recently been able to use once daily based on pharmacokinetics-pharmacodynamics in Japan. So far, there had been no reports of the prospective studies evaluating efficacy and safety of LVFX in patients with nursing and healthcare-associated pneumonia (NHCAP). This study was conducted to evaluate prospectively the efficacy and safety of LVFX in patients with NHCAP categories B and C (other antibacterial agents were allowed to use with LVFX) according to Japanese guideline for NHCAP by the Japanese Respiratory Society (JRS). LVFX 500 mg was intravenously administered once daily, and the clinical efficacy and safety were evaluated by clinical symptoms, peripheral blood laboratory findings and chest X-rays. Sixty-two patients (average age was 81.2 years old, female/male was 22/40) were firstly registered and evaluated for the safety of LVFX, and eventually 54 patients were enrolled for the evaluation of clinical efficacy of LVFX. The percentage of these 54 patients aged over 65 years old was 96.3%, NHCAP category B/C was 33/21. The efficacy of LVFX in all 54 patients evaluated was 85.2% (categories B/C of NHCAP was 81.8/90.5%). In addition, the efficacies of LVFX in each pneumonia severity category by A-DROP system by JRS in NHCAP patients were 100% in mild, 86.7% in moderate, 77.8% in severe/very severe. Nine patients (2 with liver dysfunction, 6 with renal dysfunction and 1 with thrombocytopenia) out of 62 patients were reported to have possible adverse effects of LVFX. All of the patients with liver and renal dysfunctions after starting LVFX administration demonstrated mild dysfunctions and continued LVFX treatment, and these dysfunctions normalized soon after cessation of LVFX. LVFX was changed to other antibacterial agent in one patient with thrombocytopenia, and also thrombocytopenia was normalized thereafter. In conclusion, LVFX is effective and relatively safe for categories B and C in patients with NHCAP.

With the increase in extended spectrum β-lactamase (ESBL)-producing bacteria in the community, cases are often seen in which treatment of infectious diseases with oral antimicrobial agents is difficult. Therefore, we measured the antimicrobial activities of 14 currently available oral antimicrobial agents against ESBL-producing Escherichia coli and Klebsiella pneumoniae. Based on the standard of the Clinical and Laboratory Standards Institute (CLSI), E. coli showed high susceptibility rates of 99.4% to faropenem (FRPM). In terms of fluoroquinolones, the susceptibility rate of E. coli to levofloxacin (LVFX) was low at 32.2%, whereas it showed a good susceptibility rate of 93.1% to sitafloxacin (STFX). With respect to other antimicrobial agents, susceptibility rates to fosfomycin (FOM) and colistin (CL) were more than 90% each, whereas rates of the two antimicrobial agents expected as therapeutic agents, minocycline (MINO) and sulfamethoxazole-trimethoprim (ST), were low at 62.4% and 44.3%, respectively. Based on the CLSI standard, K. pneumoniae showed high susceptibility rates to ceftibuten (CETB) (91.89%), LVFX (86.49%), and STFX (94.6%), indicating that K. pneumoniae showed higher rates than those of E. coli, particularly to fluoroquinolones. Comparison of susceptibility rates according to E. coli genotype showed that many antimicrobial agents existed to which the CTX-M-9 group showed high susceptibility rates. However, there were many agents to which the CTX-M-1 group showed low susceptibility rates, particularly to CETB (51.1%) and LVFX (17.0%). Although there was no significant difference by genotype between FRPM, STFX, and FOM, a significant difference was observed between LVFX, MINO, and ST. Antibiotic-resistant bacteria with highly pathogenic strains have spread in the community, appropriate use of oral antimicrobial agents is required., (Copyright © 2013 Japanese Society of Chemotherapy and the Japanese Association for Infectious Diseases. Published by Elsevier Ltd. All rights reserved.)

Moxifloxacin (MFLX) is a respiratory quinolone, and is effective against not only Gram-positive and negative bacteria but also anaerobes. There has been no prospective studies evaluating the efficacy and safety of MFLX in patients with nursing and healthcare-associated pneumonia (NHCAP). Therefore, we assessed the efficacy and safety of MFLX in patients with NHCAP. NHCAP patients with mild and moderate severity assessed by the A-DROP system in community-acquired pneumonia guideline proposed by Japan Respiratory Society visited our hospitals from April 2011 to March 2012. Clinical symptoms, chest X-ray films and/or computed tomography, peripheral white and red blood cell and platelet counts, serum CRP, AST, ALT, BUN, creatinine were evaluated. Forty patients were eventually evaluated, and average age was 74.1 years old, male/female were 21/19, 92.5% (37/40) of them had one or more comorbidities. Median duration of MFLX administration was 7.1 days (4-15 days). The efficacy of MFLX in all patients was 87.5% (35/40). The efficacies in each age group were 87.9% (aged over 65 years old), 85.7% (aged under 64 years old), and in each pneumonia severity group by the A-DROP system were 91.7% (mild), 85.7% (moderate). Diarrhea and swelling of the breast were observed in one patient (2.5%) after starting MFLX administration. Mild elevated transaminases were observed in three patients (7.5%), and mild renal dysfunction was observed in two patients (5.0%). All abnormally increased levels of transaminases and serum creatinine were recovered after a cessation of MFLX. MFLX is effective and safe in patients with NHCAP.

We investigated 5 metallo-β-lactamase (MBL)-positive Klebsiella isolates from Japan showing intermediate resistance to imipenem. Sequencing of the MBL gene identified a novel variant of IMP-1 with a single amino acid substitution, Glu87Gly. This variant is designated as IMP-34 where blaIMP-34 is located on a transmissible plasmid., (Copyright © 2013 Elsevier Inc. All rights reserved.)

We herein report two cases of primary ciliary dyskinesia (PCD) with different responses to macrolides. Case 1: a 17-year-old Japanese man with Pseudomonas aeruginosa infection and combined defect of both inner and outer dynein arms in the cilia was unsuccessfully treated with long-term macrolides (clarithromycin, erythromycin, and azithromycin). Case 2: a 70-year-old Japanese man with deficiency of only the inner dynein arm was successfully treated with clarithromycin. Though the reasons for the different responses to macrolides are unclear, differences of ultrastructural abnormalities of the cilia might be one of the predictive factors in PCD just as in Pseudomonas aeruginosa infection.

The antimicrobial activity of 18 antimicrobial agents were measured for the 500 Pseudomonas aeruginosa strains that had been isolated from various clinical specimens in 17 medical institutions in the Kinki district from April to July of 2008. The antimicrobial activity was excellent in the order of tobramycin (TOB), arbekacin (ABK), doripenem (DRPM), gentamicin (GM) and amikacin (AMK). Susceptible rate that was interpreted by Clinical and Laboratory Standards Institute (CLSI) was high in the order of AMK, TOB, tazobactam/piperacillin (TAZ/PIPC), DRPM, ABK. Also, the difference in susceptible rate was observed between departments, materials and institutions. Multidrug resistant strains were only 12 (2.4%) but strains that had resistance to 2 agents were 48 (9.6%), therefore, implementation of further surveillance should be continued.

We investigated the efficacy and safety of sitafloxacin (STFX) in patients with mild to moderate community-acquired pneumonia or secondary infections of chronic respiratory tract diseases. The results showed that the efficacy rate was 96.5% (111/115) in patients analyzed for efficacy. The efficacy rate by STFX administration method was 93.9% (46/49) at 50mg b.i.d., 100% (37/37) at 100 mg q.d. and 96.6% (28/29) at 100mg b.i.d. In chest X-rays, the image improvement rate in 102 patients with shadows before treatment was 94.1% (96/102). The image improvement rate by STFX administration method was 90.5% (38/42) at 50 mg b.i.d., 97.1% (33/34) at 100mg q.d. and 96.2% (25/26) at 100mg b.i.d. Side effects occurred in five out of 115 patients (4.3%). Abnormalities in hepatic function test values appeared in two patients and abnormalities in renal function test values appeared in three patients. In four cases, the abnormalities were very mild and STFX administration was continued without any treatment. In the other patient, the abnormal value rapidly returned to normal after STFX administration was discontinued. These findings indicated that STFX can be used safety in routine practice by adjusting the administration within the approved dose based on patient characteristics. Good therapeutic effects can be expected in patients with respiratory tract infections.

Extended-spectrum beta-lactamase (ESBL)-producing bacteria are known to be resistant to penicillins, cephalosporins, and monobactams because of their substrate specificity, and these bacteria are sensitive only to a narrow range of antimicrobial agents. The present study was undertaken to evaluate the efficacy of carbapenems and the new quinolones against ESBL-producing Escherichia coli, using a Monte Carlo simulation based on the pharmacokinetic/pharmacodynamic (PK/PD) theory. The time above MIC (TAM, %) served as the PK/PD parameter for carbapenems, with the target level set at 40%. The AUC/MIC served as the PK/PD parameter for the new quinolones, with the target level set at more than 125. In the analysis of drug sensitivity, the MIC50 of all carbapenems other than imipenem was low (0.03 microg/ml), while the MIC50 of the new quinolones was higher (1-2 microg/ml). The probability of achieving the PK/PD target with carba penems after two doses at the usual dose level, as determined by the Monte Carlo simulation, was high for each of the carbapenems tested (99.0% for biapenem, 99.60% for meropenem, and 95.03% for doripenem), except for imipenem. Among the new quinolones, the highest probability of achieving the PK/PD target was obtained with pazufloxacin (42.90%). Thus, the results of the present study have revealed that carbapenems are effective at the regular dose and can be used as the first-choice antibiotics for ESBL-producing E. coli because the resistance ratios for carbapenems are low compared to those of the new quinolones.

We studied the antimicrobial susceptibility of AmpC beta-lactamase-producing Escherichia coli isolates collected at ten medical institutions in the Kinki area of Japan during a 6-month period (November 2002 through April 2003). Of 2845 E. coli isolates tested, 29 (1.0%) showed a minimum inhibitory concentration (MIC) for cefazolin of more than 8 microg/ml and were three-dimensional extract test positive. In standard inoculum susceptibility tests against these 29 strains, the MIC90s for the four carbapenems tested ranged from 0.06 microg/ml to 0.5 microg/ml, and these compounds were more active than the other beta-lactams, with meropenem being the most active. The MIC90s for beta-lactams, except carbapenems, ranged from 4 microg/ml to 32 microg/ml, with cefepime being the most active. In high inoculum susceptibility tests against these strains, the MIC90s for the four carbapenems and cefepime were 8 microg/ml or less, and these compounds were more active than other beta-lactams. The MIC90s for beta-lactams, except carbapenems and cefepime, were 32 microg/ml or more. The MIC90s for the five quinolones tested ranged from 4 microg/ml to 16 microg/ml, and the order of increasing susceptibility was ciprofloxacin > levofloxacin, gatifloxacin and pazufloxacin > prulifloxacin.

We studied the susceptibility to penicillin G (PCG) and other antimicrobiotics in 235 clinical isolates of Streptococcus pneumoniae. Samples were collected between April 1 and June 30, 2000 from nine medical institutions of the Kinki Region of Japan. We classified the minimum inhibitory concentration (MIC) of PCG according to the National Committee for Clinical Laboratory Standards (NCCLS) criteria. The overall rate of all types of S. pneumoniae resistance was 53.2% (penicillin-susceptible S. pneumoniae (PSSP): 46.8%, penicillin-intermediate S. pneumoniae (PISP): 42.6%, penicillin-resistant S. pneumoniae (PRSP): 10.6%). In other antimicrobiotics, the resistance (R)/intermediate susceptibility (I) rates (R/I%) were as follows: ceftriaxone, 28.9%; cefotaxime, 7.7%; imipenem, 8.9%; meropenem, 9.8%; clarithromycin, 82.6%; clindamycin, 42.1%; levofloxacin, 0.4%; vancomycin, 0%. We used the polymerase chain reaction to study the mutations of the penicillin-binding proteins pbp1 a, pbp2b, and pbp2x in 140 strains of S. pneumoniae in the MIC for PCG was < 0.5 microgram/ml. Among the 109 strains of PSSP, 32 (29.4%) had no mutation and 77 (70.6%) showed mutation of more than one of the pbp mutations. Among the 31 strains of PISP, only 1 strain (3.2%) was not mutated. Since 70.6% of the strains classified as PSSP had pbp mutations, S. pneumoniae clearly can acquire resistance to anti-microbiotics. In the future, a comprehensive surveillance of S. pneumoniae is necessary.

The carbazomycin-producing microorganism, strain H 1051-MY 10, was determined to a strain of Streptoverticillium ehimense. Biosynthesis of carbazomycin B was studied using 14C-labeled and 13C-enriched precursors in combination with 13C NMR spectroscopy. The C-2 carbon of [2-13C]trytophan was shown to be involved at the C-3 carbon in carbazomycin B and both carbons of [1,2-13C]acetate at the C-1 and C-10 moiety of the antibiotic. [CH3-13C]Methionine was involved at the methoxyl group but not at the methyl group on the C-2 carbon of the antibiotic. Neither of the labeled carbons, [1-14C]tryptophan nor [2,3-13C]propionic acid, was detected in the antibiotic, and a progenitor of the C-2 and C-11 moiety of the antibiotic has not been determined.