Interspecies scaling of excretory amounts using allometry - retrospective analysis with rifapentine, aztreonam, carumonam, pefloxacin, miloxacin, trovafloxacin, doripenem, imipenem, cefozopran, ceftazidime, linezolid for urinary excretion and rifapentine, cabotegravir, and dolutegravir for fecal excretion

1. Interspecies allometry scaling for prediction of human excretory amounts in urine or feces was performed for numerous antibacterials. Antibacterials used for urinary scaling were: rifapentine, pefloxacin, trovafloxacin (Gr1/low; <10%); miloxacin, linezolid, PNU-142300 (Gr2/medium; 10-40%); aztreonam, carumonam, cefozopran, doripenem, imipenem, and ceftazidime (Gr3/high; >50%). Rifapentine, cabotegravir, and dolutegravir was used for fecal scaling (high; >50%). 2. The employment of allometry equation: Y = aW(b) enabled scaling of urine/fecal amounts from animal species. Corresponding predicted amounts were converted into % recovery by considering the respective human dose. Comparison of predicted/observed values enabled fold difference and error calculations (mean absolute error [MAE] and root mean square error [RMSE]). Comparisons were made for urinary/fecal data; and qualitative assessment was made amongst Gr1/Gr2/Gr3 for urine. 3. Average correlation coefficient for the allometry scaling was >0.995. Excretory amount predictions were largely within 0.75- to 1.5-fold differences. Average MAE and RMSE were within ±22% and 23%, respectively. Although robust predictions were achieved for higher urinary/fecal excretion (>50%), interspecies scaling was applicable for low/medium excretory drugs. 4. Based on the data, interspecies scaling of urine or fecal excretory amounts may be potentially used as a tool to understand the significance of either urinary or fecal routes of elimination in humans in early development.

[Comparative studies on activities of antimicrobial agents against causative organisms isolated from patients with urinary tract infections (2004). I. Susceptibility distribution]

The bacterial strains isolated from 490 patients diagnosed as having urinary tract infections (UTIs) in 14 institutions in Japan were collected between August 2004 and July 2005. The susceptibilities of them to many kinds of antimicrobial agents were measured. Of them, 577 strains were estimated as causative bacteria and used for the measurement. The strains consisted of 156 gram-positive bacterial strains (27.0%) and 421 gram-negative bacterial strains (73.0%). Against Staphylococcus aureus, arbekacin (ABK), vancomycin (VCM) showed the strongest activity and prevented the growth of all strains with 2 microg/mL. Against Enterococcus faecalis, ampicillin (ABPC) and VCM showed a strong antibacterial activity. The antibacterial activity of cephems to Escherichia coli was generally good, and especially cefozopran (CZOP) and cefpirome (CPR) showed the strongest activity (MIC90: < or = 125 microg/mL). Quinolone resistant E. coli [MIC of ciprofloxacin (CPFX): > or = 4 microg/mL] was detected at frequency of 18.8%, which was higher than that in the last year. Against Klebsiella pneumoniae, CZOP, meropenem (MEPM), and carumonam (CRMN) showed the strongest activity and prevented the growth of all strains with 0.125 microg/mL or less. The antibacterial activity of the other cephems was relatively good, and decrease in their activity observed in the last year study was not recognized. Against Serratia marcescens, imipenem (IPM) and gentamicin (GM) had the strongest antibacterial activity. Against Proteus mirabilis, CRMN showed the strongest activity and prevented the growth of all strains with 0.125 microg/mL or less. MEPM prevented the growth of all strains with 0.25 microg/mL. Next, cefmenoxime (CMX), ceftazidime (CAZ), CZOP, cefixime (CFIX), cefpodoxime (CPDX), and cefditoren (CDTR) showed a strong activity. The antibacterial activity of the drugs to Pseudomonas aeruginosa was generally low, and MIC90 of all the drugs was ranged from 32 to > 128 microg/mL except IPM and MEPM having 16 microg/mL. The antibacterial activities of CZOP and CAZ were considered to be relatively good on MIC50 comparison (MIC50: 2 microg/mL).

Susceptibility of Streptococcus mutans and Streptococcus sobrinus to cell wall inhibitors and development of a novel selective medium for S. sobrinus

Representative strains of Streptococcus mutans and Streptococcus sobrinus showed differences in susceptibility to members of the monobactam group of beta-lactam antibiotics: S. sobrinus was less sensitive than S. mutans. The minimum inhibitory concentrations of aztreonam (AZT) and carumonam, both of which belong to this group, were 2,000 microg/ml for S. sobrinus and 125 microg/ml for S. mutans. Further addition of fosfomycin, bacitracin and sodium chloride to Mitis Salivarius agar (MS) supplemented with AZT resulted in growth inhibition of S. mutans and oral streptococci other than S. sobrinus, and was therefore used as a selective medium for S. sobrinus (MS-SOB medium). The average growth recovery of laboratory and clinically isolated strains of S. sobrinus on MS-SOB medium was 74.1% compared to that on MS medium. Seventy-eight percent of clinical samples in which S. sobrinus was detected yielded pure growth of S. sobrinus on MS-SOB medium.

Comparative epileptogenic properties of two monobactam derivatives in C57, Swiss and DBA/2 mice

The behavioural and electrocortical effects of two monobactam derivatives were studied after intraperitoneal (ip) administration in DBA/2 mice, a strain genetically susceptible to sound-induced seizures, and in C57 and Swiss mice, two strains not prone to seizure. DBA/2 mice were more susceptible than Swiss and C57 mice to seizures induced by aztreonam or carumonam. No significant differences were observed between seizures elicited by aztreonam and carumonam in animals (DBA/2 only) administered intracerebroventricularly or ip. Although the main mechanism for seizure-like activity of monobactams cannot be easily determined, we believe that several mechanisms may be involved. An increased excitation of the central nervous system (CNS) by inhibition of GABA binding to receptors and a slow clearance of aztreonam and carumonam from the CNS may be postulated.

Interactions between active-site serine beta-lactamases and so-called beta-lactamase-stable antibiotics. Kinetic and molecular modelling studies

The interactions between imipenem and four monobactams and three class A beta-lactamases have been studied in detail. Despite their reputation as being beta-lactamase-stable, some of these compounds were significantly hydrolysed by the enzymes. The results obtained with the Streptomyces albus G beta-lactamase have been analysed in the light of molecular modelling studies. The discussion is extended to include other so-called beta-lactamase-stable antibiotics to demonstrate that this appellation can often be misleading.

[Recombinant human granulocyte-colony stimulating factor (rhG-CSF) treatment for spleen abscess and periostitis in a patient with chronic granulomatous disease]

A 9-year-old boy with chronic granulomatous disease was hospitalized on May, 1991, because of continued fever and pain in the right elbow. Increased bone intensity at the distal end of right humerus on x-ray and a 33 x 36 mm space-occupying lesion in the spleen on abdominal CT scan were recognized. Under a diagnosis of periosteitis and spleen abscess, intravenous infusion of rhG-CSF at a dose of 200 micrograms/m2/day was started in combination with antimicrobial therapy. Fever, tenderness, swelling in the right elbow and inflammatory indices improved three weeks after the institution of therapy. Hydrogen peroxide (H2O2) formation by neutrophil increased significantly, although intermittently, during the therapy. The spleen abscess had completely vanished on CT scan on February, 1992. The therapy was well tolerated and no significant side effects were observed. The use of rhG-CSF in combination with potent antibiotics is recommended for patients with serious infections in chronic granulomatous disease to avoid a fatal course.

Effects of quinolones on nucleoid segregation in Escherichia coli

The effects of quinolone antibiotics on nucleoid segregation in growing Escherichia coli were examined by using fleroxacin (Ro 23-6240, AM 833) as a prototype compound. At levels that were close to its MIC and induced growth arrest and filamentation, fleroxacin caused large nucleoids to appear in midcell, suggesting inhibition of nucleoid segregation. With increasing fleroxacin concentrations, nucleoids became progressively smaller, suggesting inhibition of DNA replication. Removal of fleroxacin restored normal cell and nucleoid morphology in filaments with large nucleoids but not in filaments with small nucleoids. The results are consistent with inhibition of chromosome decatenation at low quinolone concentrations (bacteriostatic effect) and DNA supercoiling at high concentrations (bactericidal effect).

Pharmacokinetics of carumonam (AMA-1080) in patients with impaired renal function and in those undergoing hemodialysis

The pharmacokinetics of carumonam (AMA-1080) were studied after a single intravenous 1.0-g dose was given to 26 subjects grouped according to their renal functions. Creatinine clearance (CLCR) was above 85, 50 to 84, 10 to 49, and below 10 ml/min/1.73 m2 in groups 1, 2, 3, and 4, respectively. All of the six patients in groups 4 were receiving maintenance hemodialysis, and they were studied both during and between hemodialysis sessions. Carumonam obeyed two-compartment model kinetics in all four group. The volume of distribution based on the area under serum concentration-time curve (Varea) did not differ significantly among the four groups, the mean value being 0.309 +/- 0.084 liter/kg. The elimination-phase (beta) half-lives were 1.53 +/- 0.36, 2.00 +/- 0.64, 5.08 +/- 1.85, and 12.8 +/- 4.1 h in groups 1, 2, 3, and 4, respectively. The 0- to 24-h cumulative urinary recoveries of carumonam were 83 +/- 11, 76 +/- 20, 58 +/- 25, and 12 +/- 9% of the administered dose in groups 1, 2, 3, and 4, respectively. The systemic and the renal clearances of carumonam decreased according to the severity of renal dysfunction, and the nonrenal clearance, which was calculated as the difference between renal and systemic clearances also decreased as CLCR decreased. A significant positive correlation existed between beta and CLCR (r = 0.847, P less than 0.01), and the beta of carumonam could be predicted by the following equation: beta (h-1) = 0.00460 X CLCR (ml/min/1.73 m2) + 0.049. Hemodialysis shortened the elimination-phase half-lives from 12.8 +/- 4.1 to 2.66 +/- 1.49 h in the six subjects in group 4. A 5-h hemodialysis in a hypothetical anephric subject weighing 60 kg was estimated to remove 51.4% of the drug present in the body at the start of hemodialysis.

Preferential hydrolysis of cis configuration compounds at the 3,4 position of monobactams by beta-lactamase from Morganella morganii

Carumonam and BO-1166 (cis configuration) were inactivated by beta-lactamase of Morganella morganii more rapidly than were aztreonam and BO-1165 (trans configuration), as demonstrated by spectrophotometric analysis and microbiological assay. An active enzyme was recovered more rapidly from the inactivated enzyme-monobactam complex derived from the cis form of monobactams than from the complex derived from the trans form of monobactams. This result suggests that the configuration at the 3,4 position on the azetidinone ring of monobactams, together with the chemical structure of the side chains attached to the azetidinone ring, may play an important role in the stability of monobactams to the beta-lactamase of M. morganii.

[Clinical evaluation of the combination of carumonam and cefotiam in the treatment of complicated urinary tract infection]

The combination of carumonam (CRMN) and cefotiam (CTM), expected to have a broader spectrum of coverage in connection with urinary tract infections, was evaluated for its effectiveness and safety at the Department of Urology, Osaka University Hospital and 17 affiliated hospitals. CRMN and CTM were given together to 109 patients with complicated urinary tract infections (UTI), of whom 65 cases satisfied the "Criteria of UTI Committee for the Evaluation of Drug Efficacy in the UTI (3rd Ed.)", which was modified by adopting the midstream urine data for women. CRMN and CTM were administered by drip or one-shot infusion at a total daily dose of 4 g (equally mixed 1 g plus 1 g each, twice a day) for 5 consecutive days or longer. The overall clinical efficacy rate in the 65 cases of complicated UTI was 72%, estimated by the criteria cited above. The efficacy rate according to the infection type groupings was 72% for the 29 patients in the 1st group, 100% for the 1 patient in the 2nd group, 100% for the 7 patients in the 3rd group, 83% for the 6 patients in the 4th group, 50% for the 14 patients in the 5th group and 75% for the 8 patients in the 6th group. The disappearance rate of both urinary Gram positive cocci and Gram negative bacilli was 83.3%. Fifteen strains appeared after the treatment, only 4 of which were Gram positive cocci. Among the 109 patients treated with CRMN+CTM, no subjective side effects were recorded and the abnormalized laboratory findings observed were: eosinophilia in one patient, increases in both GPT and GOT in one patient, and lowered creatinine clearance in one patient. With a broader spectrum and safe regimen, the combination of CRMN/CTM is recommended as the first choice against complicated UTI.

Immunization of mice with antibiotic-treated Escherichia coli results in enhanced protection against challenge with homologous and heterologous bacteria

The murine immune response to Escherichia coli exposed to subminimal inhibitory concentrations of four antibiotics was investigated. Groups of mice were injected for 8 weeks with formalin-killed bacteria and subsequently challenged with 10 x LD50 of viable E. coli. Mice receiving saline only (controls) died within 24 h. The mortality of mice immunized with ciprofloxacin-treated E. coli was significantly lower than that of mice immunized with E. coli untreated or treated with other antibiotics. Sera from mice immunized with ciprofloxacin-treated bacteria showed better bacteriostatic capacity and enhanced production of antibodies that bound to homologous and heterologous lipopolysaccharide isolated from several smooth and rough gram-negative strains. The better protection observed in mice immunized with ciprofloxacin-treated E. coli was probably due to an enhanced production of antibodies to epitopes on lipopolysaccharide that became better exposed and so more accessible after treatment with ciprofloxacin.

[Bacterial combination effect between carumonam and eight other antibiotics]

In vitro interactions between carumonam (CRMN) and 8 other antibiotics were studied using the agar dilution checkerboard technique against 88 clinical isolates of Escherichia coli, Proteus vulgaris, Serratia marcescens and Pseudomonas aeruginosa. Combinations of CRMN with 8 other antibiotics were generally additive or indifferent. Synergism was found against S. marcescens or P. aeruginosa with CRMN plus fosfomycin, gentamicin (GM) or dibekacin. Antagonism was not observed with CRMN plus any of the 8 other antibiotics tested. In a phase-contrast microscopic study, the synergism of CRMN in combination with GM were confirmed against P. aeruginosa 15846. CRMN in combination with GM demonstrated a in vivo synergy against experimental urinary tract infection caused by P. aeruginosa 15846 in mice. We think that combinations of several antibiotics with CRMN should be appropriate for initial therapy of infections because no antagonism appeared to occur with other antibiotic agents.

[Effect of combination therapy with carumonam and clindamycin on severe infections in patients with hematologic malignancies]

We evaluated the efficacy of a combination therapy with carumonam (CRMN) and clindamycin (CLDM) on severe infections in patients with hematologic malignancies. Fifty three patients were included in this study. The efficacy of the combination therapy was evaluated according to the criteria by TAKAKU et al. Fourteen cases were evaluated as excellent, and 24 cases were as good, with a total rate of effectiveness of 71.7% (38/53). It should be noted that the rate of effectiveness in patients having less than 100/microliters neutrophils was 77.3% (17/22). Adverse effects were observed in 2 patients (3.7%). One case was hepatotoxicity and the other was nephrotoxicity. Both were mild and transient, however. These observations suggested that the combination therapy with CRMN and CLDM was effective and safe for the treatment of severe infections in patients with hematologic malignancies.

[Antibacterial activity of carumonam and cefpirome on hospital strains resistant to gentamicin and cephalothin: comparison with other beta-lactam antibiotics, new fluoroquinolones, aminoglycosides and other antibiotics]

The antibacterial in vitro activity of carumonam, a new monobactam, and cefpirome, a new cephalosporin, was studied on 483 hospital strains resistant to gentamicin and cephalothin, in comparison with amikacin, azlocillin, aztreonam, cefmenoxim, cefoperazone, cefotaxim, cefsulodin (for Pseudomonas), ceftazidime, ceftriaxone, cefuroxim, chloramphenicol, ciprofloxacin, doxycycline, enoxacin, netilmicin, norfloxacin, pefloxacin, piperacillin, rifampicin, tobramycin and trimethoprim. In general the two compounds have a very good in vito activity on Enterobacteriaceae but are less active on non-fermenting microorganisms. For the Enterobacteriaceae the minimal inhibitory concentrations 90% for carumonam was less than or equal to 1.1 mg/l excepted for Enterobacter spp. (43,6 mg/l) and M. morganii (56.8 mg/l) . All the Enterobacteriaceae are susceptible to cefpirome (minimal inhibitory concentrations 90% less than or equal to 5.3 mg/l). The activity of carumonam and cefpirome on Enterobacteriaceae is comparable with that of the third generation cephalosporins. Carumonam is more active than cefpirome and other beta-lactams, ceftazidime excepted, on Pseudomonas aeruginosa and Pseudomonas spp. On the other hand, both compounds reveal to have only a low activity on the other non-fermenters which minimal inhibitory concentrations 90% values of 115.4 mg/l for carumonam and 32.0 mg/l for cefpirome.

[Clinical evaluation of the combination of carumonam and fosfomycin in the treatment of complicated urinary tract infection]

Carumonam (CRMN), the first monobactam antibiotic in Japan, has excellent activity against gram-negative bacteria and is useful in the treatment of urinary tract infections. However, it may be insufficient in the treatment of complicated urinary tract infections because of the increase in isolation of gram-positive bacteria, and it may be necessary to co-administer antibiotics active against gram-positive organisms to achieve a broader spectrum of coverage in connection with severe infections. The combination of CRMN and fosfomycin (FOM) was evaluated for its effectiveness and safety at the Department of Urology, Yamagata University Hospital and 7 affiliated hospitals. Clinical efficacy was assessed on 64 patients with complicated urinary tract infection according to the Criteria for Clinical Evaluation of Antimicrobial Agents in UTI (3rd. ed.) recommended by the Japan UTI Committee. Clinical efficacy was evaluated as excellent in 16, moderate in 32, poor in 16, with an overall clinical effectiveness rate of 75.0%, which is superior compared with CRMN alone. Of the total of 92 bacterial strains isolated, 66 (71.7%) were eradicated. Subjective adverse reaction was seen in 1 patient (1.4%), as nausea and anorexia. Slight increases in serum GOT and GPT ware recorded in 5 patients (7.1%). These findings disappeared after the termination of administration without treatment. The combination of CRMN and FOM might therefore be useful in the treatment of complicated urinary tract infections.

Multiple intravenous dose pharmacokinetic study of carumonam in healthy subjects

Steady-state pharmacokinetics of carumonam were investigated in twelve healthy adult male volunteers after 20 min intravenous infusions of three consecutive carumonam dosage regimens: 1 g every 8 h (3 g/day) from 0-72 h, 2 g every 8 h (6 g/day) from 88-120 h and 2 g every 6 h (8 g/day) from 132-216 h. Serial plasma samples were collected after the first dose of the first regimen and the last dose of all three regimens and were analysed for carumonam by a specific HPLC method. The overall mean maximal plasma concentrations were 108 and 211 mg/l at the end of infusion of 1 and 2 g, respectively. The steady-state pharmacokinetic parameters and plasma concentration-time profiles of carumonam when adjusted for dose were similar for the three regimens. The overall terminal elimination half-life was 1.4 h (range 1.1-1.8 h), the apparent volume of distribution at steady state reached 11.5 l (range 8.7-15.5 l) and the total systemic clearance amounted to 118 ml/min (range 83-158 ml/min). Considering the frequency of dosing relative to the elimination half-life, accumulation of the drug in plasma was not expected and none was found from any of the three regimens. Carumonam was well tolerated up to 8 g/day and exhibited dose-independent pharmacokinetics which were not altered upon multiple dosing.

Penetration of monobactam antibiotics (aztreonam, carumonam) into human prostatic tissue

Concomitant concentrations of monobactam antibiotics were measured in plasma and in prostatic tissue obtained by transurethral resection in 25 patients, 60-120 min after dosage. A 1-gram single intravenous injection of aztreonam or carumonam yielded mean prostatic concentrations of 6.0 mg/kg in 20 patients. Five patients who received a 2-gram dose of carumonam demonstrated average prostatic levels of 10 mg/kg. These concentrations significantly exceed MIC values for most common gram-negative urinary tract pathogens.

[Antibacterial activities of monobactams against fresh clinical isolates]

Antibacterial activities of monobactam antibiotics (carumonam (CRMN) and aztreonam (AZT] against Gram-negative bacilli isolated from inpatients in the latter half of 1987 were investigated using penicillin (PC: piperacillin (PIPC], cephems (CEPs: ceftazidime (CAZ), cefotaxime (CTX), latamoxef (LMOX), cefsulodin (CFS], carbapenem (imipenem (IPM] and pyridonecarboxylic acids (norfloxacin (NFLX) and ofloxacin (OFLX] as reference antibiotics. A total of 400 strains of 13 species, i.e. Escherichia coli, Klebsiella pneumoniae, Klebsiella oxytoca, Proteus mirabilis, Proteus vulgaris, Morganella morganii, Providencia rettgeri, Citrobacter freundii, Enterobacter cloacae, Enterobacter aerogenes, Serratia marcescens, Pseudomonas aeruginosa and Haemophilus influenzae, were used as test strains. 1. CRMN and AZT, both monobactam antibiotics, were roughly comparable in their activities and no resistant strain to these antibiotics were found among isolates of E. coli, Klebsiella spp., Proteus spp., M. morganii, P. rettgeri or H. influenzae and few resistant strains were observed among isolates of S. marcescens. On the other hand, isolates of C. freundii, Enterobacter spp. and P. aeruginosa included rather numerous strains resistant to the monobactam antibiotics. Among these cases, whereas R strains, i.e. resistant strains showing MICs greater than or equal to 50 micrograms/ml, accounted for a large proportion of strains resistant to PC and CEPs, I strains, i.e. intermediately resistant strains showing MICs between 12.5 and 25 micrograms/ml, accounted for a large proportion of strains resistant to the monobactam antibiotics. 2. Strains resistant to PIPC, a PC, were detected with high and more or less uniform frequencies over the entire spectrum of the isolates examined. 3. Antibacterial activities of CEPs varied against different bacterial species. While strains resistant to CTX, CAZ and LMOX were commonly detected with high frequencies among isolates of C. freundii, Enterobacter spp. and S. marcescens, large percentages of LMOX-resistant strains of C. freundii and Enterobacter spp. were of the I type. CTX-resistant strains were also found among isolates of P. vulgaris and M. morganii. Proportions of CEP-resistant strains of P. aeruginosa were 28% for CFS and 12% for CAZ. 4. No or few strains among the isolates of 13 species investigated were resistant to IPM, a carbapenem antibiotic, which showed the most stable antibacterial activity, but it was less active than monobactam antibiotics and CEPs against Klebsiella spp., P. mirabilis and H. influenzae.(ABSTRACT TRUNCATED AT 400 WORDS)

In vitro activity of carumonam (Ro 17-2301; AMA-1080) versus enteropathogenic and nonfermentative gram-negative rods and Legionella pneumophila

The in vitro activity of carumonam (Ro 17-2301; AMA-1080) was tested against 355 single-patient isolates, by and large enteropathogenic or nonfermentative rods. The new monobactam was inhibitory and bactericidal against the majority of diarrhea-causing members of the family Enterobacteriaceae at concentrations of less than and equal to 8 micrograms/ml. Although known to be active against Pseudomonas aeruginosa, it generally did not exhibit clinically useful activity against other nonfermenters or against Legionella pneumophila, thus confirming its narrow spectrum of activity.

N-azamonobactams. 1. The synthesis of some 3-substituted N-azamonobactam derivatives

Ring closure of the N-(tert-butyloxycarbonyl)-L-serine 2-(diphenylmethylene)hydrazide (10a) and the corresponding L-threonine derivative (10b) gave good yields of the beta-lactams 11a and 11b. Catalytic hydrogenation afforded the corresponding N-amino beta-lactams 12a and 12b. These compounds were then further transformed into 3-(S)-[[(2-amino-4-thiazolyl)-(Z)-(methoxyimino)acetyl]amino-2-oxo-1- azetidinyl]sulfamic acid analogs 18, 23, and 30a and 30b. None of these compounds exhibited any interesting biological activity.

Carumonam versus ceftazidime for urinary tract infections

Carumonam is a new monobactam antibiotic with potent activity against gram-negative aerobes. To study the efficacy and safety of carumonam for treatment of complicated and uncomplicated urinary tract infections, 54 patients were randomized to therapy with either carumonam or ceftazidime. Of 42 patients who could be evaluated, 82% of the carumonam-treated patients and 80% of the ceftazidime-treated patients were cured clinically. At 5 to 9 days posttherapy, microbiologic criteria indicated that 13 carumonam-treated patients (48%) and 8 ceftazidime-treated patients (53%) were cured. Patients with indwelling bladder catheters at the end of therapy had a markedly worse microbiologic outcome than those without catheters. Enterococcus sp. reinfection was common in both groups. Possible adverse clinical and laboratory reactions occurred in six carumonam-treated patients (21%) and four ceftazidime-treated patients (27%). Most reactions occurred at the end of therapy and resolved with discontinuation of the study drug. In this small study, carumonam appeared as safe and as effective as ceftazidime for the treatment of complicated and uncomplicated urinary tract infections.

Carumonam (Ro 17-2301; AMA-1080) compared with gentamicin for treatment of complicated urinary tract infections

Carumonam and gentamicin were compared in a prospective, randomized study of 52 patients with complicated urinary tract infections. Patients were treated with either carumonam (1 g every 8 h) or gentamicin (1 mg/kg every 8 h). The mean duration of therapy (carumonam, 8.5 days; gentamicin, 8.5 days) was similar for both groups. A total of 45% of patients treated with carumonam and 48% of those receiving gentamicin were cured, as defined by a negative culture 1 to 2 weeks after therapy. After 4 to 6 weeks, the figures were 27% for carumonam and 38% for gentamicin. In the carumonam group, there were 6 relapses and 11 reinfections. In the gentamicin group, there were eight relapses and five reinfections. Adverse effects in the carumonam group were limited to phlebitis at the intravenous infusion site in two patients; another patient developed bloody diarrhea. Nephrotoxicity was documented in two patients in the gentamicin treatment group (9%), and another patient developed minor liver function disturbances. Three patients with gentamicin-resistant carumonam-susceptible isolates were treated with carumonam, and two were cured. Urinary colonization with group D streptococci occurred in 7 of 27 (26%) carumonam-treated patients compared with 7 of 19 (37%) gentamicin-treated patients; no one required treatment. A significant correlation was found between colonization with group D streptococci and neurogenic bladder dysfunction (P less than 0.007). It is concluded that the use of the carumonam is as effective as the gentamicin regimen in the treatment of complicated urinary tract infections.

Pharmacokinetics of carumonam after single and multiple 1- and 2-g dosage regimens

The pharmacokinetics of carumonam after single and multiple intravenous administration of 1- and 2-g dosage regimens were studied in 12 young male volunteers. Plasma and urine samples were collected in serial order for 24 h and assayed by high-pressure liquid chromatography. The mean elimination half-life of carumonam was not significantly affected by either dosage regimen or single dose versus steady state, ranging from 1.3 to 1.5 h. Mean concentrations at the end of the interval were not influenced by a multiple-dose administration. The normalized volume of distribution was independent of the dose, with values ranging from 0.16 to 0.19 liters/kg. After multiple administration, carumonam was cleared from the body more rapidly: from 96.2 to 121.7 ml/min after 1 g every 8 h, and from 102.1 to 122.3 ml/min after 2 g every 8 h (P less than 0.05). After 24 h, 75.0 to 80.7% of the dose was excreted unchanged in the urine. The protein binding of carumonam to human plasma remained stable at 28%. Carumonam was well tolerated by the volunteers.

Comparative bactericidal activity of cefixime, carumonam, enoxacin and roxithromycin with those of other antibiotics against resistant Haemophilus influenzae including beta-lactam tolerant strains

One hundred isolates of Haemophilus influenzae including 50 beta-lactamase producing, five ampicillin-resistant non-beta-lactamase producing and five beta-lactam tolerant strains were tested for susceptibility (MICs and MBCs) to ampicillin, aztreonam, carumonam, cefixime, cefaclor, cefamandole, cefotaxime, imipenem, enoxacin, ciprofloxacin, roxithromycin, erythromycin, chloramphenicol, and co-trimoxazole, by a microdilution broth method. Cefotaxime, enoxacin and ciprofloxacin with MIC90 and MBC90 of less than 0.03 mg/l) were the most active antimicrobial agents tested. Cefixime, carumonam, aztreonam, and co-trimoxazole (MIC90 and MBC90 less than 0.25 mg/l) showed good activity against most strains. Roxithromycin and erythromycin had limited antibacterial activity (MIC90, 8 and 4 mg/l respectively). There were no chloramphenicol-resistant strains. Five beta-lactamase-negative strains were resistant to ampicillin, cefaclor and cefamandole but susceptible to other beta-lactams tested. Different patterns of tolerance were observed: four of five tolerant strains were tolerant to ampicillin and cefamandole, three to cefixime, cefaclor and cefotaxime, one to aztreonam. One tolerant strain was a beta-lactamase producer. Two other strains were tolerant only to co-trimoxazole.

[Clinical study of carumonam]

To evaluate the clinical efficacy of carumonam (CRMN, AMA-1080), the drug was used in the treatment of 10 patients including 4 with pneumonia and each with acute tonsillitis, chronic bronchitis, Mycoplasma pneumonia, primary atypical pneumonia (PAP), chronic pyelitis, and acute cystitis. Since beta-lactam antibiotics were not active against Mycoplasma pneumonia and PAP, these diseases were excluded from the clinical efficacy evaluation of CRMN. Responses were excellent in 1 patient and good in 7. Side effects were not observed. The laboratory test recognized slight elevations of GOT, GPT and eosinophilia in 1 patient and a slight leucopenia in another upon the administration of CRMN.

Mechanism of renal excretion of carumonam in rats, rabbits, dogs, and monkeys

The mechanism of the renal excretion of carumonam (CRMN) was investigated in rats, rabbits, dogs, and monkeys. Stop-flow analysis in dogs demonstrated that CRMN is exclusively excreted by glomerular filtration. There was no specific CRMN peak corresponding to the peak of p-aminohippuric acid (PAH) secretion or to the trough of Na+-K+ reabsorption in the stop-flow pattern. Although the PAH peak disappeared when probenecid was administered, the CRMN stop-flow pattern showed no change. In rabbits, however, the CRMN concentration peak corresponding with the PAH peak was detected in the stop-flow pattern; the CRMN peak disappeared when probenecid was administered. The pharmacokinetic parameters in plasma, such as the area under the concentration-time curve, the half-life, and the clearance rate, were affected by probenecid in rats, rabbits, and monkeys, but not in dogs. The results suggest that the renal excretion of CRMN in dogs takes place exclusively through glomerular filtration. In rats, rabbits, and monkeys, however, CRMN is excreted through both glomerular filtration and renal tubular secretion.

Determination of the monocyclic beta-lactam antibiotic carumonam in plasma and urine by ion-pair and ion-suppression reversed-phase high-performance liquid chromatography

A sensitive and selective high-performance liquid chromatography method has been developed for the determination of the new monocyclic beta-lactam antibiotic carumonam in plasma and urine. The method for plasma involves protein precipitation with acetonitrile and removal of lipids with dichloromethane; urine is diluted with buffer. Separation and quantification are achieved using a mobile phase based on either ion-suppression or ion-pair chromatography on a reversed-phase column with UV detection. The limit of determination is 0.5 micrograms/ml plasma, using a 0.5-ml specimen, and 25 micrograms/ml urine, using a 50-microliter specimen. The inter-assay reproducibility is generally better than 4% when an internal standard is used. Since beta-lactam antibiotics may degrade on storage, close attention must be paid to the stability of these drugs in biological fluids; novel measures to prevent degradation on storage are described. The assay has been successfully applied to the analysis of several thousand samples from pharmacokinetic studies, including a study involving patients with impaired renal function.

Carumonam enhances reactivity of Escherichia coli with mono- and polyclonal antisera to rough Escherichia coli J5

Escherichia coli O111 reacts only slightly with antiserum to its rough mutant E. coli J5 in an enzyme-linked immunosorbent assay. When E. coli O111 was grown in the presence of sub-MICs of the monocyclic beta-lactam antibiotic carumonam, however, the enzyme-linked immunosorbent assay titer increased from 1,280 to 81,920. When the bacteria were grown in the presence of carumonam, the titer that was obtained with antiserum against E. coli O111 was not affected. This reaction was abolished after this antiserum was absorbed with E. coli J5 in the case of the carumonam-treated strain, whereas this absorption did not affect the reaction with E. coli O111. Thus, the O-antigenic side chain of E. coli O111 seems to be affected if this strain is cultured in the presence of carumonam. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed a relative loss of the O polysaccharide in E. coli O111 when this strain was grown in the presence of carumonam. Also, a much stronger reaction of the antibiotic-affected lipopolysaccharide with a monoclonal antibody against E. coli J5 lipopolysaccharide was shown in immunoblots. The results of this study indicate that there is a synergism between certain antibiotics and monoclonal antibodies, something that could have clinical implications.

[Comparative antibacterial activity of a new monobactam, carumonam (RO 17-2301, AMA 1080) on hospital bacteria resistant to beta lactams]

In vitro activity of a new monobactam, carumonam (RO 17-2301, AMA 1080) was tested against 370 hospital bacterial isolates. Results were compared to aztreonam, cefotaxime, cefmenoxime, latamoxef, ceftazidime, ceftriaxone, pefloxacin against Enterobacteriaceae, to aztreonam, piperacillin, cefoperazone, cefsulodin, ceftazidime, imipenem and pefloxacin against P. aeruginosa. All Enterobacteriaceae strains produced cephalosporinases and all P. aeruginosa strains were ticarcillin resistant. MIC 90% of carumonam against Enterobacteriaceae strains was lower than 0.25 mg/l for P. mirabilis, P. vulgaris, P. stuartii, Salmonella sp., ranged from 0.25 to 0.5 mg/l for Klebsiella sp. and S. marcescens, from 1 to 2 mg/l for E. coli and P. morganii, and from 4 to 8 mg/l for C. freundii and E. cloacae. The rate of strains inhibited with 4 mg/l of carumonam was 95.3%. So carumonam was at the second place from eight tested products, after latamoxef (97.5% of susceptible strains). Carumonam was active against second generation cephalosporins resistant strains when these strains were susceptible or intermediate to cefotaxime. Strains resistant to this compound escaped to its action. Its activity against A. calcoaceticus was weak (22.6% of strains inhibited by 4 mg/l), but was superior to that of cefsulodin against ticarcillin resistant P. aeruginosa strains (54.5 versus 16.1% of susceptible strains). However carumonam was less active against this last species than ceftazidime or imipenem (92.6 and 91% of susceptible strains respectively).

Comparative in vitro activity of carumonam (Ro 17-2301/AMA-1080), a new monobactam, and ceftriaxone against aerobic or facultative gram-negative isolates

Carumonam (Ro 17-2301/AMA-1080) is a new monobactam antibiotic. A comparative in vitro evaluation with ceftriaxone was undertaken against 153 gram-negative clinical aerobic or facultative bacteria, both producers and nonproducers of beta-lactamase. Results indicated that carumonam had an enhancement of activity for Pseudomonas aeruginosa, Klebsiella oxytoca, Citrobacter freundii and Enterobacter cloacae and parallelled that of ceftriaxone against Escherichia coli, Klebsiella pneumoniae, Proteus spp. and Serratia marcescens. It can be concluded that carumonam could be an alternative of interest for the treatment of patients with infections due to gram-negative strains presumably or proven to be multiresistant.

Pharmacokinetics and dose recommendations of carumonam in renal failure

The pharmacokinetics of (Z)-[[[(2-aminothiazol-4-yl)[[(2S,3S)-2-(hydroxymethyl)-4-oxo-1- sulfoazetidin-3-yl]carbamoyl]methylene]amino]oxo]acetic acid, disodium salt (carumonam, Ro 17-2301) after a 2 g intravenous infusion (20 min) were evaluated in 10 healthy volunteers and 20 patients with various degrees of renal failure. The main results of the kinetic parameters in healthy volunteers (mean + SD) corrected for zero infusion time and 70 kg body weight were: t1/2 alpha, 29 +/- 12 min; t1/2 beta, 108 +/- 27 min; AUCtot, 327 +/- 40 mg h/l; Vdss, 12.2 +/- 1.5 l/70 kg; urinary recovery, 78.7 +/- 8.2%; total clearance 103 +/- 13 ml/min; renal clearance, 85 +/- 13 ml/min. Because of the large variation in the degree of renal insufficiency, calculations of the mean values for the pharmacokinetic parameters in the patient group were not generally justified with the exception of the volume of distribution (Vdss = 14.4 +/- 3.0 l/70 kg). To derive dose recommendations, a regression analysis was performed using values from both the volunteer and patient group for the total area under curve (AUCtot) and glomerular filtration rate (GFR), divided by the mean AUCtot value for the volunteers. This curve can be interpreted as giving the dose reduction factor (DRF) as a function of GFR, where by definition, DRF = 1 for healthy (and young) subjects. Using this method of equivalent areas, no (or only a slight) dose reduction is necessary for patients with GFR values above 40 ml/min.(ABSTRACT TRUNCATED AT 250 WORDS)

[In vitro activity of carumonam (RO 17-2301) on hospital bacteria]

Minimal inhibitory concentrations (MICs) of carumonam (RO 17-2301), a new synthetic antibacterial agent of the monobactam group, were evaluated by agar dilution for 399 hospital isolates. RO 17-2301 was inactive against Gram positive and anaerobic bacteria. Most Enterobacteriaceae were inhibited by concentrations less than 1 microgram/ml, with mode MICs approximating 0.03 micrograms/ml except for Providencia (0.016), Citrobacter (0.06), Serratia (0.06) and Enterobacter (0.12). A few strains, most of which were Enterobacter or Citrobacter, had high MICs (greater than 8 micrograms/ml). RO 17-2301 was less active against Pseudomonas aeruginosa (mode MIC 2 micrograms/ml) and Acinetobacter (mode MIC 8-16 micrograms/ml). Haemophilus influenzae sp. were sensitive to RO 17-2301 (mode MIC 0.12-0.25), regardless of beta-lactamase production status; MICs ranged from 0.06 to 0.25 micrograms/ml for Meningococci, and from 0.008 to 0.06 for Gonococci except for a few strains that had higher MICs (0.25 to 0.5 and even 4 micrograms/ml). In vitro activity of RO 17-2301 on Gram negative bacteria proved similar to that of third-generation cephalosporins; cefotaxime-resistant Enterobacteriaceae are resistant to RO 17-2301.

Disposition of carumonam (AMA-1080/Ro 17-2301), a new N-sulfonated monocyclic beta-lactam, in rats and dogs

Rats and dogs were given a single 20-mg/kg dose of [14C]carumonam intramuscularly or intravenously. In rats, the level in plasma of [14C]carumonam administered intramuscularly peaked (29.1 micrograms/ml) 15 min after dosing and then declined with an apparent elimination half-life of 16.2 min. Intramuscular injection of [14C]carumonam to dogs gave a peak level (36.8 micrograms/ml) in plasma at 20 min and an apparent elimination half-life of 51.7 min. After administration of the intravenous dose, apparent elimination half-lives were 13.1 and 52.7 min in rats and dogs, respectively. In both animals, the radioactivity in plasma was made up largely (greater than 80%) of unchanged carumonam, which was protein bound to only a small extent. In rats given [14C]carumonam intramuscularly, radioactivity was distributed widely in tissues, with relatively high concentrations in the kidney and liver. The radioactivity concentration in the rat fetus was relatively low, as was that in milk. In both rats and dogs carumonam did not undergo extensive metabolism; the most prominent metabolite was AMA-1294, the compound resulting from beta-lactam ring hydrolysis. [14C]carumonam and metabolites were mostly eliminated from the bodies within 72 h in rats and 120 h in dogs. In both animals, a large amount of the dosed radioactivity was excreted in the urine largely as unchanged antibiotic. The remainder was eliminated in the feces via bile. AMA-1294 was eliminated from the bodies of rats and dogs at a considerably slower rate than was unchanged carumonam. In rats, [14C]carumonam was eliminated by both glomerular filtration (67%) and tubular secretion (33%); the renal elimination of [14C]AMA-1294 was only by glomerular filtration.

In vitro activity of carumonam (RO 17-2301) and twelve other antimicrobials against clinical isolates of Pseudomonas aeruginosa

Minimal inhibitory concentrations of the monobactam carumonam (RO 17-2301) and twelve other antimicrobials were determined using agar dilution against 140 recent non-replicate clinical isolates of Pseudomonas aeruginosa. The most active drugs were ciprofloxacin, amikacin, imipenem and ceftazidime, inhibiting 96, 91, 90 and 86 percent of the strains, respectively, at or below the susceptibility threshold. The monobactams carumonam and aztreonam were active against 78 and 65 percent of the strains, respectively. Tobramycin inhibited 68 percent of the strains, and gentamicin and netilmicin 50 and 21 percent, respectively. Analysis of correlation coefficients revealed a low correlation between imipenem and the other beta-lactams and a remarkably good correlation between the beta-lactams (excepting imipenem) and the aminoglycosides.

The in-vitro activity of SQ 82,291, a new monobactam, in comparison with aztreonam

The in-vitro activity of a new monobactam antibiotic, SQ 82,291, was compared with that of aztreonam against 529 strains of aerobic and facultatively anaerobic bacteria. SQ 82,291, which is absorbed orally when administered as an ester, has shown good activity against different bacteria of the family Enterobacteriaceae and Haemophilus influenzae. The susceptibility of SQ 82,291 is lower than that to aztreonam in the species that were sensitive and SQ 82,291 showed no activity at all against staphylococci and strict anaerobes (like aztreonam); unlike aztreonam SQ 82,291 was not effective against Pseudomonas aeruginosa.

Intramolecular nucleophilic amino attack in a monobactam: synthesis and stability of (2S,3S)- 3-[(2R)-2-amino-2-phenylacetamido]-2-methyl-4-oxo-1- azetidinesulfo nic acid

The potentially orally bioavailable arylglycine-substituted monobactam, (2S,3S)- 3-[(2R)-2-amino-2-phenylacetamido]-2-methyl-4-oxo-1- azetidinesulfonic acid, was prepared as a crystalline solid. No significant antibacterial activity [i.e., MICs were greater than 128 (micrograms/mL)] was found when the monobactam was tested against Gram positive and Gram negative bacteria. Solution instability (greater than 2,000 times less stable than aztreonam) due to intramolecular nucleophilic amine attack on the beta-lactam is believed to be a contributing factor to the poor microbiological activity.

Pharmacokinetics of carumonam in patients with renal insufficiency

The pharmacokinetics of carumonam after a single 1,000-mg intravenous infusion (20 min) were evaluated in four groups of subjects who had various degrees of renal impairment: group 1, CLCR greater than 60 ml/min; group 2, CLCR = 30 to 60 ml/min; group 3, CLCR = 10 to 30 ml/min; and group 4, CLCR less than 10 ml/min). The elimination half-life of carumonam increased with decreasing creatinine clearance (CLCR) from 1.7 h in group 1 to 11.3 h in group 4. Peak carumonam concentration (103 micrograms/ml) and steady-state volume of distribution (12.8 liters) did not change with decreasing CLCR. Total body clearance (r = 0.98), renal clearance (r = 0.98), and nonrenal clearance (r = 0.67) of carumonam correlated with decreasing CLCR. Mean nonrenal clearance was 21 ml/min in group 1 and 12 ml/min in group 4. With regard to dosage, patients with a CLCR above 60 ml/min should receive their standard maintenance dose of carumonam without any changes; patients with a CLCR between 30 and 60 ml/min should receive the dose every 12 h; and individuals with a CLCR between 10 and 30 ml/min should be given the dose once a day. Patients with a CLCR of less than 10 ml/min should receive one-half of the dose once a day. Our recommended dosage regimens should produce within the CLCR borderlines of each group average plasma concentrations that are between one and two times that achieved in normal subjects with a t.i.d. dosage regimen.