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The emergence of bacteria resistant to beta-lactam/beta-lactamase inhibitor combinations is insufficiently studied, wherein the role of the inoculum effect (IE) in decreased efficacy is unclear. To address these issues, 5-day treatments with doripenem and doripenem/relebactam combination at different ratios of the agents were simulated in a hollow-fiber dynamic model against carbapenemase-producing K. pneumoniae at standard and high inocula. Minimal inhibitory concentrations (MICs) of doripenem alone and in the presence of relebactam at two inocula were determined. Combination MICs were tested using traditional (fixed relebactam concentration) and pharmacokinetic-based approach (fixed doripenem-to-relebactam concentration ratio equal to the therapeutic 24-h area under the concentration-time curve (AUC) ratio). In all experiments, resistant subpopulations were noted, but combined simulations reduced their numbers. With doripenem, the IE was apparent for both K. pneumoniae isolates in combined treatments for one strain. The pharmacokinetic-based approach to combination MIC estimation compared to traditional showed stronger correlation between DOSE/MIC and emergence of resistance. These results support (1) the constraint of relebactam combined with doripenem against the emergence of resistance and IE; (2) the applicability of a pharmacokinetic-based approach to estimate carbapenem MICs in the presence of an inhibitor to predict the IE and to describe the patterns of resistance occurrence. [ABSTRACT FROM AUTHOR]

ABSTRACT: Objective: Both ertapenem and other carbapenems, including imipenem, meropenem, and doripenem, are recommended in the treatment of extended-spectrum-β-lactamase (ESBL)-producing Enterobacterales infection. However, whether ertapenem is as effective as other carbapenems for ESBL-producing Enterobacterales remains unclear. Therefore, this meta-analysis was conducted to compare the clinical efficacy of ertapenem versus other carbapenems in the treatment of ESBL-producing Enterobacterales infection. Methods: PubMed, Web of Science, and Cochrane Library were searched from their inception to 29 November 2022. Only studies comparing ertapenem and other carbapenems in the treatment of patients with ESBL-producing Enterobacterales infections were included. Results: A total of six studies meeting selection criteria were identified. Overall, ertapenem was associated with a significantly lower 30-d mortality when compared with other carbapenems (10.7% [46/431] vs. 17.7% [104/586]; risk ratio [RR], 0.61; 95% CI: 0.40–0.91). The ertapenem group exhibited a significantly shorter length of hospital stay than the other carbapenem groups (mean differences, -6.02 d; 95% CI, -9.39 to -2.64). No significant differences were noted between ertapenem and other carbapenem groups in terms of rates of clinical cure or improvement (RR, 1.11; 95% CI: 0.97–1.25) and microbiological eradication (RR, 1.01; 95% CI: 0.97–1.06). Conclusions: Ertapenem could be as effective as other carbapenems in the treatment of patients with ESBL-producing Enterobacterales infections.

In this study, we established a novel capillary electrophoresis method for monitoring the concentration of doripenem in human plasma. As a time-dependent antibiotic, doripenem maximizes its antibacterial effects and minimizes the potential for antibiotic resistance through careful therapeutic drug monitoring. Two online preconcentration techniques, field-enhanced sample stacking (FESS) and sweeping, were coupled to enhance the detection sensitivity. Briefly, an uncoated fused silica capillary (40 cm × 50 μm i.d) was rinsed with a high conductivity buffer (HCB) composed of 150 mM phosphate buffer (NaH2PO4, pH 2.5) and 20% methanol. A large sample plug prepared in a low-conductivity phosphate buffer (50 mM NaH2PO4, pH 2.5) was then hydrodynamically injected (5 psi, 80 s) into the capillary. Under an applied voltage of −30 kV, the analyte was accumulated at the FESS boundary and swept by the negatively charged micelles toward the UV detector. Plasma samples were pretreated by solid-phase extraction (SPE) to eliminate endogenous interferences. The validation results demonstrated a high coefficient of determination (r2 > 0.9995) for the regression curve with impressive precision and accuracy: relative standard deviation (RSD) <5.86% and relative error <4.63%. The limit of detection (LOD, S/N = 3) for doripenem was determined to be 0.4 μg/mL. Compared to the conventional micellar electrokinetic chromatography method, our developed method achieved a sensitivity enhancement of up to 488-fold for doripenem. Furthermore, the newly developed method successfully quantified doripenem concentrations in plasma samples obtained from patients accepting doripenem regimens, proving its application potential in the clinical realm. [ABSTRACT FROM AUTHOR]

The occurrence of antibiotic pollution has become a concerning issue to public health, where the adsorption of antibiotics on bentonite-based adsorbent represents an attractive solution to reduce the antibiotic residue in wastewater. In this work, the bentonite-chitosan composite was synthesised and the adsorption isotherms of amoxicillin, ampicillin, and doripenem were investigated experimentally at temperatures between 303.15 and 323.15 K. The bentonite-chitosan composite was characterised by scanning electron microscope, electron dispersive X-ray spectrophotometer, surface area and porosity analyser, powder X-ray diffractometer, Fourier transform infrared spectrometer, and thermogravimetric analyser to examine the structure of the synthesised adsorbent. The experimental data were also correlated with models of Langmuir, Freundlich, Toth, and Dubinin-Radushkevich. The experimental results showed an enhanced adsorption of all antibiotics on the bentonite-chitosan composite compared with raw bentonite despite having a much smaller BET surface area and pore volume. On the other hand, the Toth model provided the best estimates on the adsorption isotherms, though Langmuir constants were mostly recovered particularly in the lower temperature range. From the fitting results, the adsorptions of all antibiotics were implied to be endothermic and associated with monolayer formation. Within the tested temperatures, the adsorption capacities of the bentonite-chitosan composite computed by Toth model were found to be 51.9–86.1 mg g−1 for amoxicillin, 66.1–83.3 mg g−1 for ampicillin, and 78.4–96.0 mg g−1 for doripenem.

Information regarding carbapenem-induced liver injury is limited, and the rate of liver injury caused by meropenem (MEPM) and doripenem (DRPM) remains unknown. Decision tree (DT) analysis, a machine learning method, has a flowchart-like model where users can easily predict the risk of liver injury. Thus, we aimed to compare the rate of liver injury between MEPM and DRPM and construct a flowchart that can be used to predict carbapenem-induced liver injury. We investigated patients treated with MEPM (n = 310) or DRPM (n = 320) and confirmed liver injury as the primary outcome. We used a chi-square automatic interaction detection algorithm to construct DT models. The dependent variable was set as liver injury from a carbapenem (MEPM or DRPM), and factors including alanine aminotransferase (ALT), albumin-bilirubin (ALBI) score, and concomitant use of acetaminophen were used as explanatory variables. The rates of liver injury were 22.9% (71/310) and 17.5% (56/320) in the MEPM and DRPM groups, respectively; no significant differences in the rate were observed (95% confidence interval: 0.710–1.017). Although the DT model of MEPM could not be constructed, DT analysis showed that the incidence of introducing DRPM in patients with ALT >22 IU/L and ALBI scores > −1.87 might be high-risk. The risk of developing liver injury did not differ significantly between the MEPM and DRPM groups. Since ALT and ALBI score are evaluated in clinical settings, this DT model is convenient and potentially useful for medical staff in assessing liver injury before DRPM administration. [ABSTRACT FROM AUTHOR]

The dataset reported in this article describes the adsorption isotherms of amoxicillin, ampicillin, and doripenem onto bentonite. Batch adsorption experiments were carried out on single antibiotic solutions with various dosage of bentonite across temperatures from 30 to 50 °C. The adsorbent loading dataset was later obtained by measuring the concentration of antibiotic solution at adsorption equilibrium via UV-Vis spectrophotometer. The dataset was also fitted using various isotherm models including Freundlich, Langmuir, Toth, Hill, and Dubinin-Radushkevich models to further analyze the adsorption behavior. On top of that, orthogonal regression was applied to avoid fitting biasness, whereby the fitting results revealed the highest adsorption capacities of 82.259 mg g−1 for amoxicillin, 78.851 mg g−1 for ampicillin, and 93.278 mg g−1 for doripenem using Langmuir model, which gave an accurate representation of the adsorption isotherm dataset that was consistent with the results of Toth and Hill model.

The emergence of bacteria resistant to beta-lactam/beta-lactamase inhibitor combinations is insufficiently studied, wherein the role of the inoculum effect (IE) in decreased efficacy is unclear. To address these issues, 5-day treatments with doripenem and doripenem/relebactam combination at different ratios of the agents were simulated in a hollow-fiber dynamic model against carbapenemase-producing K. pneumoniae at standard and high inocula. Minimal inhibitory concentrations (MICs) of doripenem alone and in the presence of relebactam at two inocula were determined. Combination MICs were tested using traditional (fixed relebactam concentration) and pharmacokinetic-based approach (fixed doripenem-to-relebactam concentration ratio equal to the therapeutic 24-h area under the concentration-time curve (AUC) ratio). In all experiments, resistant subpopulations were noted, but combined simulations reduced their numbers. With doripenem, the IE was apparent for both K. pneumoniae isolates in combined treatments for one strain. The pharmacokinetic-based approach to combination MIC estimation compared to traditional showed stronger correlation between DOSE/MIC and emergence of resistance. These results support (1) the constraint of relebactam combined with doripenem against the emergence of resistance and IE; (2) the applicability of a pharmacokinetic-based approach to estimate carbapenem MICs in the presence of an inhibitor to predict the IE and to describe the patterns of resistance occurrence.

The aim of the study was to determine the efficacy of carbapenem-only combination treatments derived from four approved drugs (meropenem, doripenem, ertapenem and imipenem) against a MDR strain of P. aeruginosa in a Galleria mellonella larvae infection model. G. mellonella larvae were infected with P. aeruginosa NCTC 13437 (carrying the VIM 10 carbapenamase) and the efficacy of the six possible dual, four triple, and one quadruple carbapenem combination(s) were compared to their constituent monotherapies. Four of these combinations showed significantly enhanced survival compared to monotherapies and reduced the bacterial burden inside infected larvae but without complete elimination. Bacteria that survived combination therapy were slower growing, less virulent but with unchanged carbapenem MICs—observations that are consistent with a persister phenotype. In vitro time-kill assays confirmed that the combinations were bactericidal and confirmed that a low number of bacteria survived exposure. Mass spectrometry was used to quantify changes in the concentration of carbapenems in the presence of carbapenemase-carrying P. aeruginosa. The rate of degradation of individual carbapenems was altered, and often significantly reduced, when the drugs were in combinations compared with the drugs alone. These differences may account for the enhanced inhibitory effects of the combinations against carbapenem-resistant P. aeruginosa and are consistent with a 'shielding' hypothesis. In conclusion, carbapenem combinations show promise in combating MDR P. aeruginosa and are worthy of additional study and development. [ABSTRACT FROM AUTHOR]

In the context of difficult-to-treat carbapenem-resistant Pseudomonas aeruginosa infections, we evaluated imipenem, meropenem, and doripenem combinations against eleven carbapenemase-producing P. aeruginosa isolates. According to the widespread global distribution of high-risk clones and carbapenemases, four representative isolates were selected: ST175 (OXA-2/VIM-20), ST175 (VIM-2), ST235 (GES-5), and ST111 (IMP-33), for efficacy studies using a sepsis murine model. Minimum inhibitory concentration (mg/L) ranges were 64–256 for imipenem and 16–128 for meropenem and doripenem. In vitro, imipenem plus meropenem was synergistic against 72% of isolates and doripenem plus meropenem or imipenem against 55% and 45%, respectively. All combinations were synergistic against the ST175, ST235, and ST155 clones. In vivo, meropenem diminished the spleen and blood bacterial concentrations of four and three isolates, respectively, with better efficacy than imipenem or doripenem. The combinations did not show efficacy compared with the more active monotherapies, except for imipenem plus meropenem, which reduced the ST235 bacterial spleen concentration. Mortality decreased with imipenem plus meropenem or doripenem for the ST175 isolate. Results suggest that carbapenem combinations are not an alternative for severe infections by carbapenemase-producing P. aeruginosa. Meropenem monotherapy showed in vivo efficacy despite its high MIC, probably because its dosage allowed a sufficient antimicrobial exposure at the infection sites. [ABSTRACT FROM AUTHOR]

Relevance. The tendency to a decrease in sensitivity of bacterial agents to old antibiotics, as well as the slowdown in creation of new medications, dictate the need to develop effective approaches to combat bacterial resistance.Aim. Evaluation of the applicability of a pharmacokinetically-based approach to predicting anti-mutant effectiveness of combined therapy with doripenem and levofloxacin against gram-negative bacteria Pseudomonas aeruginosa.Material and methods. A collection strain of Pseudomonas aeruginosa was used in the study. The values of MPC (mutant prevention concentration) of the combination of doripenem and levofloxacin were evaluated at a ratio of their concentrations equal to therapeutic ratios of the area under the pharmacokinetic curve in the in vitro dynamic model. 5-day treatments with clinical doses of doripenem and levofloxacin individually and in combination were simulated. Bacteria-containing medium was sampled during the experiments and plated on agar media containing 2MIC of each antibiotic.Results. The MPCs of doripenem and levofloxacin decreased 4 times when used in combination compared to MPC values when used separately. P.aeruginosa population was enriched with resistant mutants during monotherapy with each medication; the number of the bacteria did not decrease or even increased by the end of observation period. The use of doripenem/levofloxacin combination completely prevented development of resistance to both drugs in P.aeruginosa. The observed anti-mutant effect of antibiotic combination was consistent with higher (compared to monotherapy) values of the time during which the concentration of the antibiotic exceeded MPC (T>MPC).Conclusion. The anti-mutant effectiveness of combined therapy with doripenem and levofloxacin increased with the decrease in the values of MPC of antibiotics when used simultaneously, which consequently led to the increase in the values of T>MPC. Obtained results confirm the applicability of a pharmacokinetically-based approach to the estimation of MPC of combined antibiotics for predicting anti-mutant effectiveness of combination therapy in the treatment of infections caused by gram-negative bacteria.

The aim of this study was to determine whether fingolimod could synergize the antibacterial activity of doripenem against carbapenem-resistant Escherichia coli (CREC) and its potential as an antibiotic adjuvant for doripenem. The E. coli used in this study had the blaKPC gene and became resistant to many classes of antibiotics, particularly carbapenems. The minimum inhibitory concentrations (MICs) of fingolimod and doripenem were determined. To investigate the synergistic action between fingolimod and doripenem, synergy checkerboard, growth curve, and time-kill analyses were performed. A motility test was also performed using a semi-solid medium to determine whether fingolimod could inhibit the motility of E. coli, one of its virulence mechanisms. The expression levels of carbapenemase-, motility-, and efflux pump-related genes suppressed by fingolimod were analyzed by quantitative polymerase chain reaction (qPCR). Our study demonstrated that the combination of fingolimod and doripenem inhibited carbapenemase, biological activity and other CREC virulence factors. This study findings suggest the potential of fingolimod as an adjuvant to prevent antibiotic resistance in CREC. [ABSTRACT FROM AUTHOR]

Introduction: Clinically, doripenem therapy for nosocomial pneumonia remains a serious concern. The purpose of this meta-analysis was to explore the efficacy and the safety of doripenem therapy for nosocomial pneumonia in comparison with other antimicrobial agents. Methods: Studies were eligible for inclusion only if they directly compared the clinical effectiveness of doripenem and other antimicrobial agent therapies for nosocomial pneumonia in adult patients between 1 January 2000 and 30 April 2022. All studies were included if they reported one or more of the following outcomes: clinical cure rate, microbiological cure rate, all-cause mortality, and adverse events. Results: Six randomized controlled trials and three retrospective studies were included in the meta-analysis. There were 952 patients in the doripenem group and 1183 patients in the comparator group. The comparator antimicrobial agents included imipenem/cilastatin, meropenem, and piperacillin/tazobactam. Seven studies had a high risk of bias. Doripenem therapy for nosocomial pneumonia had a microbiological cure rate, a clinical cure rate, an all-cause mortality, and adverse events similar to those of comparators. Conclusions: The efficacy and the safety of doripenem therapy for nosocomial pneumonia were comparable with those of comparators. Randomized controlled trials are needed to confirm the role of doripenem in nosocomial pneumonia therapy. [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate the pharmacokinetics (PK) of doripenem in healthy Chinese subjects and evaluate the optimal dosage regimens of doripenem. A randomized, single-dose, three-period, self-crossover controlled extended-infusion clinical trial was conducted with 12 healthy Chinese subjects. Plasma and urine samples were collected to determine doripenem concentrations. Non-compartmental and population PK analysis were performed to characterize the PK of doripenem. The Monte Carlo simulation was employed to optimize dosing regimens based on the probability of target attainment of doripenem against pathogens with different minimum inhibitory concentrations (MIC). All 12 healthy Chinese subjects completed the study, and the doripenem was well tolerated. The study showed linearity relationships in the peak plasma concentration and the area under the concentration-time curve after intravenous infusion of doripenem from 0.25 g to 1.0 g. The cumulative urinary recovery rate of doripenem was 68.1–72.0% within 24 h. PPK modeling showed a two-compartmental model, with first-order elimination presenting the best fit for doripenem PK. Monte Carlo simulation results showed that 1.0 g q12h or 0.5 g q8h was an optimal regimen for pathogens susceptible to doripenem (MIC ≤ 1 mg/L); while high dose and extended infusion (1 g, q8h, 4 h infusion) was proposed for unsusceptible pathogens (2 ≤ MIC ≤ 8 mg/L). In the dose range of 0.25 to 1.0 g, doripenem showed linear pharmacokinetics. Doripenem at 1.0 g with a prolonged infusion time of 4 h was predicted to be effective against pathogens with MICs as high as 8 mg/L. [ABSTRACT FROM AUTHOR]

The inoculum effect (IE) is a well-known phenomenon with beta-lactams. At the same time, the IE has not been extensively studied with carbapenem/carbapenemase inhibitor combinations. The antibiotic-to-inhibitor concentration ratio used in susceptibility testing can influence the in vitro activity of the combination. To explore the role of these factors, imipenem/relebactam and doripenem/relebactam MICs were estimated against six Klebsiella pneumoniae carbapenemase (KPC)-producing Klebsiella pneumoniae strains at standard inocula (SI) and high inocula (HI) by two methods: with a fixed relebactam concentration and with a fixed, pharmacokinetic-based carbapenem-to-relebactam concentration ratio. The combination MICs at HI, compared to SI, increased with most of the tested strains. However, the IE occurred with only two K. pneumoniae strains regardless of the MIC testing method. The relationship between the MICs at SI and the respective inoculum-induced MIC changes was observed when the MICs were estimated at pharmacokinetic-based carbapenem-to-relebactam concentration ratios. Thus, (1) IE was observed with both carbapenem/relebactam combinations regardless of the MIC testing method; however, IE was not observed frequently among tested K. pneumoniae strains. (2) At HI, carbapenem/relebactam combination MICs increased to levels associated with carbapenem resistance. (3) Combination MICs determined at pharmacokinetic-based carbapenem-to-inhibitor concentration ratios predict susceptibility elevations at HI in KPC-producing K. pneumoniae. [ABSTRACT FROM AUTHOR]

Abstract Background Yersinia pseudotuberculosis infection can occur in an immunocompromised host. Although rare, bacteremia due to Y. pseudotuberculosis may also occur in immunocompetent hosts. The prognosis and therapeutic strategy, especially for immunocompetent patients with Y. pseudotuberculosis bacteremia, however, remains unknown. Case presentation A 38-year-old Japanese man with a mood disorder presented to our hospital with fever and diarrhea. Chest computed tomography revealed consolidation in the right upper lobe with air bronchograms. He was diagnosed with pneumonia, and treatment with intravenous ceftriaxone and azithromycin was initiated. The ceftriaxone was replaced with doripenem and the azithromycin was discontinued following the detection of Gram-negative rod bacteria in 2 sets of blood culture tests. The isolated Gram-negative rod bacteria were confirmed to be Y. pseudotuberculosis. Thereafter, he developed septic shock. Doripenem was switched to cefmetazole, which was continued for 14 days. He recovered without relapse. Conclusions We herein report a case of septic shock due to Y. pseudotuberculosis infection in an adult immunocompetent patient. The appropriate microorganism tests and antibiotic therapy are necessary to treat patients with Y. pseudotuberculosis bacteremia.

OBJECTIVE: This study aimed to evaluate the penetration of moxifloxacin and doripenem into the pleural fluid (PF) using a rabbit model of empyema. METHODS: An empyema was induced using the intrapleural injection of turpentine (1 mL), followed 24 h later by instillation of 5 mL Klebsiella Pneumoniae (ATCC 33495), Fusobacterium nucleatum (ATCC 25586) and Streptokok Pneumoniae (ATCC 6305) into the pleural space. After an empyema was corroborated, Moxifloxacin (25 mg/kg-1) and Doripenem (20 mg/kg-1) were administered intraperitoneally. To determine the levels of antibiotics measured by High-Performance Liquid Chromatography in pleural and blood samples were obtained serially at 8, 24, 48 and 72nd hour. RESULTS: The penetration of both antibiotics into the PF was very good. The penetration rate of doripenem (area under the curve (AUC) for PF/blood (AUCPF/AUCblood) ratio=1.68) was better than moxifloxacin (ratio=0.78). Equalization time between the PF and blood concentration of doripenem was more quickly than moxifloxacin. Peak PF concentration of moxifloxacin was 0,81 μg/mL-1 and occurred 8 h after infusion and then gradually decreased; at the beginning of the blood and pleural fluid concentrations of doripenem were equal. While the pleura concentration was increasing, blood concentration was almost the same. Doripenem reached a peak concentration (0.54 μg/ml) 24 h post-administration. CONCLUSION: Differences were found in the penetration of the two antibiotics. Doripenem had convenient penetration PF compared to moxifloxacin. Due to the differences between human and rabbit pleural thickness, doripenem's pleural penetration should be examined in infection models in animals with equal pleura thickness and clinical trials.

Abstract Background Despite the high mortality of patients with sepsis and carbapenem-resistant bacteria infection, appropriate antimicrobial therapies are yet to be established. Here, we have reported the case of a patient with pneumonia that subsequently developed by carbapenem-resistant Pseudomonas aeruginosa infection and was treated with a continuous high-dose infusion of doripenem. Case presentation We started a continuous intravenous infusion of doripenem 3 g/day although the 59-year-old woman (body weight, 45 kg) had developed septic acute kidney injury, followed by continuous renal replacement therapy (the effluent flow rate was 650 mL/h). The minimum inhibitory concentration (MIC) of doripenem was 8 mg/L. The concentration of unbound doripenem in the serum was measured by using high-performance liquid chromatography. Twenty hours after the initial dose, the patient’s serum level of doripenem was 47.8 μg/mL; the level decreased to 33.6 μg/mL at 111 h after initial dosing. The unbound doripenem concentration in the serum was maintained four times above the MIC throughout the treatment. After the completion of 11 days of dosing, the patient was discharged from the intensive care unit. During the treatment period, the MIC remained at 8 mg/L. Conclusions A continuous high-dose infusion of doripenem is a potentially efficient strategy for the treatment of antimicrobial-resistant bacteria. Moreover, therapeutic drug monitoring may be useful for patients displaying variable pharmacokinetics, because the MIC is generally high in resistant bacteria.

The aim of the study was to determine the efficacy of carbapenem-only combination treatments derived from four approved drugs (meropenem, doripenem, ertapenem and imipenem) against a MDR strain of P. aeruginosa in a Galleria mellonella larvae infection model. G. mellonella larvae were infected with P. aeruginosa NCTC 13437 (carrying the VIM 10 carbapenamase) and the efficacy of the six possible dual, four triple, and one quadruple carbapenem combination(s) were compared to their constituent monotherapies. Four of these combinations showed significantly enhanced survival compared to monotherapies and reduced the bacterial burden inside infected larvae but without complete elimination. Bacteria that survived combination therapy were slower growing, less virulent but with unchanged carbapenem MICs—observations that are consistent with a persister phenotype. In vitro time-kill assays confirmed that the combinations were bactericidal and confirmed that a low number of bacteria survived exposure. Mass spectrometry was used to quantify changes in the concentration of carbapenems in the presence of carbapenemase-carrying P. aeruginosa. The rate of degradation of individual carbapenems was altered, and often significantly reduced, when the drugs were in combinations compared with the drugs alone. These differences may account for the enhanced inhibitory effects of the combinations against carbapenem-resistant P. aeruginosa and are consistent with a ‘shielding’ hypothesis. In conclusion, carbapenem combinations show promise in combating MDR P. aeruginosa and are worthy of additional study and development.

In the context of difficult-to-treat carbapenem-resistant Pseudomonas aeruginosa infections, we evaluated imipenem, meropenem, and doripenem combinations against eleven carbapenemase-producing P. aeruginosa isolates. According to the widespread global distribution of high-risk clones and carbapenemases, four representative isolates were selected: ST175 (OXA-2/VIM-20), ST175 (VIM-2), ST235 (GES-5), and ST111 (IMP-33), for efficacy studies using a sepsis murine model. Minimum inhibitory concentration (mg/L) ranges were 64–256 for imipenem and 16–128 for meropenem and doripenem. In vitro, imipenem plus meropenem was synergistic against 72% of isolates and doripenem plus meropenem or imipenem against 55% and 45%, respectively. All combinations were synergistic against the ST175, ST235, and ST155 clones. In vivo, meropenem diminished the spleen and blood bacterial concentrations of four and three isolates, respectively, with better efficacy than imipenem or doripenem. The combinations did not show efficacy compared with the more active monotherapies, except for imipenem plus meropenem, which reduced the ST235 bacterial spleen concentration. Mortality decreased with imipenem plus meropenem or doripenem for the ST175 isolate. Results suggest that carbapenem combinations are not an alternative for severe infections by carbapenemase-producing P. aeruginosa. Meropenem monotherapy showed in vivo efficacy despite its high MIC, probably because its dosage allowed a sufficient antimicrobial exposure at the infection sites.

The aim of this study was to determine whether fingolimod could synergize the antibacterial activity of doripenem against carbapenem-resistant Escherichia coli (CREC) and its potential as an antibiotic adjuvant for doripenem. The E. coli used in this study had the blaKPC gene and became resistant to many classes of antibiotics, particularly carbapenems. The minimum inhibitory concentrations (MICs) of fingolimod and doripenem were determined. To investigate the synergistic action between fingolimod and doripenem, synergy checkerboard, growth curve, and time-kill analyses were performed. A motility test was also performed using a semi-solid medium to determine whether fingolimod could inhibit the motility of E. coli, one of its virulence mechanisms. The expression levels of carbapenemase-, motility-, and efflux pump-related genes suppressed by fingolimod were analyzed by quantitative polymerase chain reaction (qPCR). Our study demonstrated that the combination of fingolimod and doripenem inhibited carbapenemase, biological activity and other CREC virulence factors. This study findings suggest the potential of fingolimod as an adjuvant to prevent antibiotic resistance in CREC.

The aim of this study was to investigate the pharmacokinetics (PK) of doripenem in healthy Chinese subjects and evaluate the optimal dosage regimens of doripenem. A randomized, single-dose, three-period, self-crossover controlled extended-infusion clinical trial was conducted with 12 healthy Chinese subjects. Plasma and urine samples were collected to determine doripenem concentrations. Non-compartmental and population PK analysis were performed to characterize the PK of doripenem. The Monte Carlo simulation was employed to optimize dosing regimens based on the probability of target attainment of doripenem against pathogens with different minimum inhibitory concentrations (MIC). All 12 healthy Chinese subjects completed the study, and the doripenem was well tolerated. The study showed linearity relationships in the peak plasma concentration and the area under the concentration-time curve after intravenous infusion of doripenem from 0.25 g to 1.0 g. The cumulative urinary recovery rate of doripenem was 68.1–72.0% within 24 h. PPK modeling showed a two-compartmental model, with first-order elimination presenting the best fit for doripenem PK. Monte Carlo simulation results showed that 1.0 g q12h or 0.5 g q8h was an optimal regimen for pathogens susceptible to doripenem (MIC ≤ 1 mg/L); while high dose and extended infusion (1 g, q8h, 4 h infusion) was proposed for unsusceptible pathogens (2 ≤ MIC ≤ 8 mg/L). In the dose range of 0.25 to 1.0 g, doripenem showed linear pharmacokinetics. Doripenem at 1.0 g with a prolonged infusion time of 4 h was predicted to be effective against pathogens with MICs as high as 8 mg/L.

The inoculum effect (IE) is a well-known phenomenon with beta-lactams. At the same time, the IE has not been extensively studied with carbapenem/carbapenemase inhibitor combinations. The antibiotic-to-inhibitor concentration ratio used in susceptibility testing can influence the in vitro activity of the combination. To explore the role of these factors, imipenem/relebactam and doripenem/relebactam MICs were estimated against six Klebsiella pneumoniae carbapenemase (KPC)-producing Klebsiella pneumoniae strains at standard inocula (SI) and high inocula (HI) by two methods: with a fixed relebactam concentration and with a fixed, pharmacokinetic-based carbapenem-to-relebactam concentration ratio. The combination MICs at HI, compared to SI, increased with most of the tested strains. However, the IE occurred with only two K. pneumoniae strains regardless of the MIC testing method. The relationship between the MICs at SI and the respective inoculum-induced MIC changes was observed when the MICs were estimated at pharmacokinetic-based carbapenem-to-relebactam concentration ratios. Thus, (1) IE was observed with both carbapenem/relebactam combinations regardless of the MIC testing method; however, IE was not observed frequently among tested K. pneumoniae strains. (2) At HI, carbapenem/relebactam combination MICs increased to levels associated with carbapenem resistance. (3) Combination MICs determined at pharmacokinetic-based carbapenem-to-inhibitor concentration ratios predict susceptibility elevations at HI in KPC-producing K. pneumoniae.

The adsorption of Doripenem (beta-lactam antibiotic belonging to the subgroup carbapenem) from aqueous solution using bentonite as the adsorbent was studied at various pH of the solution. The doripenem loaded in bentonite which called doripenem-bentonite composite was subsequently used as the antibacterial agent. The effect of pH on the adsorption of doripenem onto bentonite was studied at pH 2 to 10 at an initial concentration of 200 mg/L and temperature of 30oC. The kinetics of adsorption was also studied, and the results were adjusted by pseudo-first-order and pseudo-second-order models, and the result indicates that pseudo-first-order gave better performance in representing the kinetics data of adsorption of doripenem onto bentonite. The adsorption isotherm of doripenem onto bentonite could be described well by the Langmuir model. Buffer solution at pH 3 gave better release of doripenem from the surface of bentonite. The microbiological testing results indicate that doripenem-bentonite composite has potential application to inhibit the growth of Staphylococcus aureus and other bacteria.

Background: Yersinia pseudotuberculosis infection can occur in an immunocompromised host. Although rare, bacteremia due to Y. pseudotuberculosis may also occur in immunocompetent hosts. The prognosis and therapeutic strategy, especially for immunocompetent patients with Y. pseudotuberculosis bacteremia, however, remains unknown.Case Presentation: A 38-year-old Japanese man with a mood disorder presented to our hospital with fever and diarrhea. Chest computed tomography revealed consolidation in the right upper lobe with air bronchograms. He was diagnosed with pneumonia, and treatment with intravenous ceftriaxone and azithromycin was initiated. The ceftriaxone was replaced with doripenem and the azithromycin was discontinued following the detection of Gram-negative rod bacteria in 2 sets of blood culture tests. The isolated Gram-negative rod bacteria were confirmed to be Y. pseudotuberculosis. Thereafter, he developed septic shock. Doripenem was switched to cefmetazole, which was continued for 14 days. He recovered without relapse.Conclusions: We herein report a case of septic shock due to Y. pseudotuberculosis infection in an adult immunocompetent patient. The appropriate microorganism tests and antibiotic therapy are necessary to treat patients with Y. pseudotuberculosis bacteremia. [ABSTRACT FROM AUTHOR]

Purpose: Clearance via renal replacement therapy (RRT) can significantly alter the pharmacokinetic profile of drugs. The aim of this study was (i) to improve the use of clinical trial data and (ii) to provide a model that allows quantification of all aspects of drug elimination via RRT including adsorption to dialysis membranes and/or degradation of the drug in the dialysate. Methods: An integrated dialysis pharmacometric (IDP) model was developed to simultaneously incorporate all available RRT information. The sensitivity, accuracy and precision of the IDP model was compared to conventional approaches in clinical trial simulations and applied to clinical datasets of teicoplanin and doripenem. Results: The IDP model was more accurate, precise and sensitive than conventional plasma-concentration-based approaches when estimating the clearanceRRT (relative bias <1%). In contrast to conventional approaches, adsorption and degradation were quantifiable using the IDP model (relative bias: −1.1% and − 1.9%, respectively). Applied to clinical data, clearanceRRT, drug degradation (effluent-half-lifedoripenem: 13.5 h−1) and adsorption (polysulphone adsorption capacityteicoplanin: 31.2 mg) were assessed. Conclusion: The IDP model allows accurate, precise and sensitive characterization of clearanceRRT, adsorption and degradation. Successful quantification of all aspects of clearanceRRT in clinical data demonstrated the benefit of the IDP model as compared to conventional approaches. [ABSTRACT FROM AUTHOR]

Introduction: Valproic acid is a commonly used antiepileptic drug. Combining valproate derivatives with carbapenem antibiotics is associated with a potential drug interaction that decreases serum concentration of valproate and may expose the patient to uncontrolled seizure risk from valproate subtherapeutic concentration. Raising awareness of this drug interaction among health care providers including emergency department physicians, neurologists, and pharmacists is highly needed. The aim of this article was to review the current literature about the potential drug interaction resulting from combining valproate derivatives with carbapenem antibiotics and to establish therapeutic recommendations regarding their use together. Methods: A review of the literature was conducted using Medline (through PubMed), Ovid, Embase, Cochrane library using the following keywords: valproate, valproic acid, carbapenem, ertapenem, doripenem, meropenem, imipenem, and valproate drug interaction. In addition, a manual search through major journals for articles referenced in PubMed was performed. Related publications from January 1998 till November 2018 were included in the initial search. Relevant publications were reviewed, and data regarding patients, type of carbapenem used, valproic acid dosing and level, interaction severity, and clinical outcome were summarized. Results and Discussion: Few clinical trials and multiple case reports have shown that carbapenem antibiotics including meropenem, ertapenem, imipenem, and doripenem can decrease the serum concentration of valproate derivatives leading to a subtherapeutic serum concentration and seizures in some patients. Valproic acid serum concentration may be significantly decreased with addition of a carbapenem antibiotic but generally return toward normal shortly after discontinuation of the carbapenem antibiotic. Conclusions: Generally, the concurrent use of carbapenem antibiotics with valproate derivatives should be avoided due to the potential of drug-drug interaction that results in subtherapeutic valproate serum concentration. Other antimicrobial agents should be considered as alternatives to carbapenems but if a concurrent carbapenem is necessary, using an additional antiepileptic agent is recommended. Therapeutic drug monitoring of valproate serum concentrations is warranted when a carbapenem-valproic acid combination therapy is unavoidable. [ABSTRACT FROM AUTHOR]

OBJECTIVE: This study aimed to evaluate the penetration of moxifloxacin and doripenem into the pleural fluid (PF) using a rabbit model of empyema. METHODS: An empyema was induced using the intrapleural injection of turpentine (1 mL), followed 24 h later by instillation of 5 mL Klebsiella Pneumoniae (ATCC 33495), Fusobacterium nucleatum (ATCC 25586) and Streptokok Pneumoniae (ATCC 6305) into the pleural space. After an empyema was corroborated, Moxifloxacin (25 mg/kg-1) and Doripenem (20 mg/kg-1) were administered intraperitoneally. To determine the levels of antibiotics measured by High-Performance Liquid Chromatography in pleural and blood samples were obtained serially at 8, 24, 48 and 72nd hour. RESULTS: The penetration of both antibiotics into the PF was very good. The penetration rate of doripenem (area under the curve (AUC) for PF/blood (AUCPF/AUCblood) ratio=1.68) was better than moxifloxacin (ratio=0.78). Equalization time between the PF and blood concentration of doripenem was more quickly than moxifloxacin. Peak PF concentration of moxifloxacin was 0,81 µg/mL-1 and occurred 8 h after infusion and then gradually decreased; at the beginning of the blood and pleural fluid concentrations of doripenem were equal. While the pleura concentration was increasing, blood concentration was almost the same. Doripenem reached a peak concentration (0.54 µg/ml) 24 h post-administration. CONCLUSION: Differences were found in the penetration of the two antibiotics. Doripenem had convenient penetration PF compared to moxifloxacin. Due to the differences between human and rabbit pleural thickness, doripenem's pleural penetration should be examined in infection models in animals with equal pleura thickness and clinical trials. [ABSTRACT FROM AUTHOR]

Introduction: Renal replacement therapy (RRT) is widely used in the treatment of septic acute kidney injury. However, little is known about how the adsorption properties of hemofilters used in RRT affect antibiotic concentration. Because a cytokine-adsorption membrane is frequently used in RRT, it is important to determine the antibiotic adsorption capacity of this membrane. Objective: The present study aimed to investigate the antibiotic adsorption capacity of different hemofilter membranes by in vitro experiments using 2 antibacterial agents (linezolid and doripenem). Methods: We performed experimental hemofiltration in vitro using polyacrylonitrile (AN69ST), polymethylmethacrylate (PMMA), and polysulfone (PS) hemofilters for 1,440 min. The test solution was a 1,000-mL substitution fluid containing 30 µg/mL linezolid and 120 µg/mL doripenem. We measured drug concentrations at the inlet, outlet, and filtrate ports of the hemofilters for 1,440 min and calculated the sieving coefficient (SC) and adsorption rate (Ra) of the drugs onto the hemofilters. Results: The amount of linezolid adsorbed onto AN69ST, PMMA, and PS membranes was decreased relative to that in the control group at 15 min (p < 0.05). However, no SC for linezolid was obtained thereafter. The Ra of linezolid onto AN69ST, PMMA, and PS membranes was higher than that in the control group (p < 0.05). In contrast, no significant differences were observed in the concentrations and Ra values of doripenem adsorbed onto AN69ST, PMMA, and PS membranes compared with those in the control group. Conclusions: Doripenem was not adsorbed onto PMMA, PS, and AN69ST membranes. Linezolid was adsorbed onto PMMA, PS, and AN69ST membranes, but only temporarily, and this did not affect drug bioavailability. [ABSTRACT FROM AUTHOR]

Traditionally, the antibacterial activity of β-lactam antibiotics in the presence of β-lactamase inhibitors is determined at the fixed inhibitor concentration. This traditional approach does not consider the ratio of antibiotic-to-inhibitor concentrations achieved in humans. To explore whether an alternative pharmacokinetically based approach to estimate MICs in combinations is predictive of antimicrobial efficacy, the effects of imipenem and doripenem alone and in combination with relebactam were studied in time-kill experiments against carbapenemase-producing Klebsiella pneumoniae. The carbapenem-to-relebactam concentration ratios in time-kill assays were equal to the therapeutic 24-h area under the concentration-time curve (AUC) ratios of the drugs (1.5/1). The simulated levels of carbapenem and relebactam were equal to their concentrations achieved in humans. When effects of combined regimens were plotted against respective C/MICs, a sigmoid relationship was obtained only with MICs determined by pharmacokinetically based method. The effectiveness of both carbapenems in the presence of relebactam was comparable by the results of time-kill experiments. These findings suggest that (1) antibiotic/inhibitor MICs determined at a pharmacokinetically based concentration ratio allow an adequate assessment of carbapenem susceptibility in carbapenemase-producing K. pneumoniae strains and can be used to predict antibacterial effects; (2) in time-kill experiments, the effects of imipenem and doripenem in the presence of relebactam are comparable.

Hospital-acquired pneumonia terminologically unites all types of pneumonia that arise in hospitalized patients: pneumonia in patients beyond artificial lungs ventilation (hospital pneumonia, medical aid-associated pneumonia) and hospital acquired pneumonia related to ALV (HAalv) or ventilator-associated pneumonia (VAP). A considerable difference of the hospital-acquired pneumonia from the community-acquired one is a different etiologic structure, which considerably complicates the choice of antibacterial drugs, at the stage of empirical therapy a necessity arises to use antibiotics active against community and hospital flora. The role of carbapenems, doripenem in particular, in therapy of hospital-acquired pneumonia is leading due to its high activity against the resistant flora.

The aims of this study were to evaluate the pharmacokinetics of doripenem (Finibax®, Doribax®, S-4661), a parenteral carbapenem antibiotic, in pediatric patients based on concentrations of doripenem in plasma after administration of 20 mg/kg 2 or 3 times daily and to evaluate the dosing regimens by using Monte-Carlo pharmacokinetic-pharmacodynamic simulations. Population pharmacokinetic analysis was performed by using 190 plasma concentrations of doripenem from 99 patients (2 months-13 years old). The two-compartment model well described the doripenem plasma concentrations in pediatric patients. Body weight was found to be the most significant influential factor. Gender was also found to be a significant covariate although the effect was relatively small. Monte-Carlo simulations indicated that 20 mg/kg over 1 h infusion would give 90% probability of target attainment for 40% of time above minimum inhibitory concentration against Haemophilus influenzae and Streptococcus pneumoniae , major causative pathogens in pediatric infections, and that 40 mg/kg, the highest approved dose for Japanese pediatric patients, administered over 3 h infusion achieved 98.6% against 8 μg/mL. The developed population pharmacokinetic model of doripenem and Monte-Carlo simulations for pediatric patients should provide useful information for understanding the pharmacokinetic and pharmacokinetic-pharmacodynamic characteristics of doripenem and for optimal treatment of pediatric patients. [ABSTRACT FROM AUTHOR]

Febrile neutropenia is often observed in patients with hematologic malignancies, especially in those with acute leukemia. Meropenem has potent and broad antibacterial activity against gram-positive and gram-negative bacteria, and is recommended as first-line empiric therapy for febrile neutropenia. In contrast, the safety and efficacy of doripenem in patients with febrile neutropenia and hematologic malignancies is limited. In this randomized, prospective, cooperative, open-label trial, we compared doripenem (1.0 g every 8 h) to meropenem (1.0 g every 8 h) as first-line empiric antibacterial treatment of febrile neutropenia. To evaluate efficacy and safety, 133 hospitalized patients with acute leukemia or high-risk myelodysplastic syndrome, who developed febrile neutropenia during or after chemotherapy, were randomized to each drug. Resolution of fever within 3 to 5 days without treatment modification (i.e., the primary endpoint) did not significantly differ between the doripenem and meropenem groups (60.0% vs. 45.6%, respectively; P = 0.136). However, resolution of fever within 7 days of treatment was significantly higher in the doripenem group than in the meropenem group (78.4% vs. 60.2%, respectively; P = 0.037). Similar rates of adverse events (grades 1–2) were observed in both groups. Thus, we conclude that both drugs are safe and well-tolerated for the treatment of febrile neutropenia in patients with acute leukemia or high-risk myelodysplastic syndrome, and that the clinical efficacy of doripenem is noninferior to that of meropenem. UMIN Clinical Trial Registry number: 000006124 [ABSTRACT FROM AUTHOR]

Objectives: We have previously identified group B Streptococcus (GBS) clinical isolates with reduced penicillin susceptibility (PRGBS) that were non-susceptible to cefotaxime; however, the rates of cefotaxime and ceftriaxone non-susceptibility among PRGBS isolates have never been reported. Therefore, we first determined the MICs of 22 antibacterial drugs/compounds for 74 PRGBS isolates and then determined the rates of cefotaxime and ceftriaxone non-susceptibility among these isolates.Methods: We used 74 clinical PRGBS isolates, previously collected in Japan and confirmed to harbour relevant amino acid substitutions in PBP2X. We also used 80 penicillin-susceptible GBS (PSGBS) clinical isolates as controls. The MICs of 22 antibacterial drugs/compounds for all 154 GBS isolates were determined via microdilution and/or agar dilution methods, as recommended by the CLSI.Results: The rates of non-susceptibility/resistance to ampicillin, cefotaxime, ceftriaxone and levofloxacin for the 80 PSGBS isolates were 0%, 0%, 0% and 30%, respectively, but were 15% (P = 0.0003), 28% (P < 0.0001), 36% (P < 0.0001) and 93% (P < 0.0001) for the 74 PRGBS isolates, respectively. No PRGBS isolates were identified to be non-susceptible to meropenem, doripenem, vancomycin, quinupristin/dalfopristin, daptomycin or linezolid.Conclusions: We found that cefotaxime- and ceftriaxone-non-susceptible PRGBS isolates occur at relatively high rates in Japan. Importantly, this finding suggests that the range of drugs likely to be effective in treating PRGBS infections may be limited compared with those available for PSGBS infections; therefore, clinicians should exercise care when considering drug choice and efficacy for PRGBS infections. [ABSTRACT FROM AUTHOR]

Objectives: To examine the impact on carbapenem resistance of mutations in Escherichia coli PBP2 detected in clinical isolates showing increased MICs of imipenem, but not of meropenem.Methods: The mutations in the PBP2-encoding gene mrdA were introduced into E. coli DH5α using the helper plasmid pTKRED. β-Lactam MICs were determined by broth microdilution and interpreted according to EUCAST. Mutants were screened for secondary mutations by WGS. To detect a possible fitness cost related to these mutations, the generation times of the mutants and E. coli DH5α were measured and their cell morphology was examined.Results: The 10 mutation patterns introduced into mrdA increased the MICs of imipenem and doripenem in all cases and of meropenem and mecillinam in some cases, but had no effect on ertapenem resistance. While no significant alteration of the generation time of the mutants could be detected, several mutants showed increased transverse diameters and thus altered cell morphology.Conclusions: Here we describe mutation patterns in PBP2 that contribute to increased MICs of carbapenems for clinical isolates of E. coli. We show that different mutations affect carbapenem MICs differently and that the mutations do not impact generation time, although some mutations affect cell morphology. [ABSTRACT FROM AUTHOR]

As a natural raw material to replace synthetic chemicals, cellulose and its derivatives are the most popular choices in the pharmaceutical industry. For drug delivery applications, cellulose is usually used as a cellulose nanocrystal (CNC). CNC-based hydrogels are widely utilized for drug delivery because drug molecules can be encapsulated in their pore-like structures. This study aims to develop CNC hydrogels for the delivery of doripenem antibiotics. CNC was obtained from jackfruit peel extraction, and alginate was used as a network polymer to produce hydrogels. Ionotropic gelation was used in the synthesis of CNC-alginate hydrogel composites. The maximum adsorption of doripenem by CNC was 65.7 mg/g, while the maximum adsorption by CNC-alginate was 98.4 mg/g. One of the most challenging aspects of drug delivery is predicting drug release from a solid matrix using simple and complex mathematical equations. The sigmoidal equation could represent the doripenem release from CNC, while the Ritger-Peppas equation could describe the doripenem release from CNC-Alginate. The biocompatibility testing of CNC and CNC-alginate against a 7F2 cell line indicates that both materials were non-toxic. [ABSTRACT FROM AUTHOR]

The fan-associated pneumonia currently is a leading reason of mortality of patients in resuscitation and intensive care unit. Development of the disease is accompanied by serious clinical and economic consequences. The adequate antibacterial therapy plays the determining role in the favorable outcome in pneumonia. Doripemen is a new parenteral 1-beta-methyl-carbapenem that was launched into the pharmaceutical market of Russia in 2008.The purpose of this review is to generalize the results accumulated to this moment on effectiveness of doripenem in therapy of fan-associated pneumonia.

Currently, one of the most common issues in medicine is antibiotics resistance. This relates to nosocomial and to communityacquired infections. This problem is common for economically developed countries of the whole world and in its significance must be placed side by side with issues of the threat to national security. In Russia annual mortality from nosocomial infection remains high and, unfortunately, this indicator doesn’t reduce from year to year [1].

the article presents the results of a retrospective study conducted in the period from 2008 to 2011 in Moscow’s hospitals. The aim of the study was to compare the clinical and pharmacoeconomical efficacy of carbapenems in nosocomial pneumonia treatment. The study included 87 patients divided into 3 groups according to the therapy (imipenem, meropenem, doripenem). There were no statistically significant differences in clinical efficacy of carbapenems. Pharmacoeconomic analysis showed more profitable use of imipenem.

Background: Pneumonia is a bacterial lower respiratory tract infection that has a high morbidity rate. The gram-negative pathogen Pseudomonas aeruginosa is a significant cause of nosocomial infections and ventilator-associated pneumonias and is mainly treated by carbapenems. Doripenem is a carbapenem drug, which has a broad-spectrum antibacterial activity. The aim of this study was to develop doripenem-loaded chitosan microparticles for pulmonary administration to provide more efficient treatment for pneumonia. Methods: Ionotropic gelation and the spray-drying method were used to obtain doripenem-loaded chitosan microparticles with different lactose, trehalose, and L-leucine concentrations. Physicochemical characteristics, in vitro drug release properties, and aerodynamics properties were investigated and in vitro antimicrobial susceptibility tests of the formulations were performed. Assessment of aerodynamic properties of the powders, including Mass Median Aerodynamic Diameter, size distribution, and fine particle fraction (FPF), were performed using a Next Generation Impactor. Cytotoxicity of the fabricated microparticles was assessed using the Calu-3 cell airway epithelial cell line. Results: Optimum microparticles were produced using a combination of ionotropic gelation and spray-drying methods. Spray-dried microparticle production yield was relatively high (74.03% ± 3.88% to 98.23% ± 1.70%). Lactose, trehalose, and L-leucine were added to the formulation to prevent aggregation produced by the ionotropic gelation spray-drying method. Each formulation's encapsulation efficiency was above 78.98% ± 2.37%. The doripenem-loaded microparticle mean diameter ranged from 3.8 ± 0.110 to 6.9 ± 0.090 μm. Microparticles with 20% (w/w) L-leucine had the highest FPF ratio indicating the best aerosolization properties of the formulations. The efficacy of the formulations as an antibacterial agent was increased by forming doripenem-loaded microparticles compared to blank microparticles. P. aeruginosa showed the same susceptibility to all doripenem-loaded microparticle formulations. Cell viability of microparticles was between 70% ± 0.08% and 90% ± 0.04% at 0.5 and 10 mg/mL concentration, respectively. Conclusions: Doripenem-loaded microparticles, produced using a combination of ionotropic gelation and spray-drying methods, are suitable for pulmonary drug delivery based on their particles size, zeta potential, cytotoxicity and high production yield. To our knowledge, this is the first study that microparticles containing doripenem were produced and characterized. [ABSTRACT FROM AUTHOR]

SUMMARY: New antimicrobial drugs for treatment of complicated urinary tract infection (cUTI) are generally assessed in randomized, double‐blind, noninferiority clinical trials. Robust historical data for the active comparator inform on treatment effect estimation, yet typically do not substitute for the active comparator data in the proposed trial. We report design options for a phase 3 trial of cUTI using a Bayesian hierarchical model and historical data from 2 well‐executed phase 3 registrational trials of doripenem. The methodology is directly applicable to other phase 3 noninferiority settings. In addition to the research design application, we provide a novel methodology for assessing the robustness of type I error control. The model borrows heavily from the prior data when the current active comparator parameter estimate approximated the historical estimate. In contrast, the model had restricted borrowing when the 2 estimates were very different. The alternative trial design, with or without the inclusion of futility stopping criteria, provides a framework for future cUTI phase 3 trials. [ABSTRACT FROM AUTHOR]

Abstract: The infections caused by multidrug resistant bacteria are widely treated with carabapenem antibiotics as a drug of choice, and human serum albumin (HSA) plays a vital role in binding with drugs and affecting its rate of delivery and efficacy. So, we have initiated this study to characterize the mechanism of doripenem binding and to locate its site of binding on HSA by using spectroscopic and docking approaches. The binding of doripenem leads to alteration of the environment surrounding Trp‐214 residue of HSA as observed by UV spectroscopic study. Fluorescence spectroscopic study revealed considerable interaction and complex formation of doripenem and HSA as indicated by Ksv and Kq values of the order of 104 M−1 and 1012 M−1 s−1, respectively. Furthermore, doripenem quenches the fluorescence of HSA spontaneously on a single binding site with binding constant of the order of 103 M−1, through an exothermic process. Van der Waals forces and hydrogen bonding are the major forces operating to stabilize HSA‐doripenem complex. Circular dichroism spectroscopic study showed changes in the structure of HSA upon doripenem binding. Drug displacement and molecular docking studies revealed that the binding site of doripenem on HSA is located on subdomain IB and III A. This study concludes that, due to significant interaction of doripenem on either subdomain IB or IIIA of HSA, the availability of doripenem on the target site may be compromised. Hence, there is a possibility of unavailability of threshold amount of drug to be reached to the target; consequently, resistance may develop in the bacterial population. [ABSTRACT FROM AUTHOR]

Background: In view of the current low efficacy of bacterial infection treatment the common trend towards searching for antibiotic systems exhibiting synergistic action is well justified. Among carbapenem analogues a particularly interesting option is provided by combinations of clavulanic acid with meropenem, which have proven to be especially effective. Results: Determination of the minimal inhibitory concentration (MIC) along with the method based on flow cytometry constitutes an important tool in the identification of bacterial sensitivity to active substances. Within this study the inhibitory effect of doripenem, clavulanic acid and the doripenem-clavulanate acid system was analyzed in relation to such bacteria as Salmonella enteritidis, Salmonella typhimurium, Staphylococcus aureus, Klebsiella pneumoniae, Escherichia coli, Pseudomonas aeruginosa, Proteus vulgaris, Clostridium butyricum and Clostridium pasteurianum, Acinetobacter baumannii, Enterobacter aerogenes. The lowest MIC, amounting to 0.03 μg/mL, was observed for the doripenem-clavulanate acid system in the case of E. coli ATCC 25922. In turn, the lowest MIC for doripenem applied alone was recorded for K. pneumoniae ATCC 31488, for which it was 0.1 μg/mL. The strain which proved to be most resistant both to doripenem and the doripenem-clavulanate acid system, was A. baumannii, with MIC of 32 μg/mL (clinical isolate) and 16 μg/mL (reference strain). Cytometric analysis for P. aeruginosa ATCC 27853 and S. aureus ATCC 25923 showed changes in cells following exposure to limiting concentrations of the active substance. Conclusions: Analysis of MIC supplies important information concerning microbial sensitivity to active substances, mainly in terms of limiting concentrations causing mortality or vitality of the tested species, which is essential when selecting appropriate antibiotic therapy. [ABSTRACT FROM AUTHOR]

• Antibiotic pollution has led to serious public health crisis and local ecology disruption. • Low cost materials were used for adsorption to control the antibiotic pollution. • Statistical physics models were used to provide new insights onto the adsorption mechanisms. • Molecular dynamics simulation revealed that Van der Waals forces are involved between bentonite and the antibiotics. Due to the inappropriate wastewater discharge, antibiotic contamination in the environment has caused significant public health issues and local ecosystem disruption. Given its benefits, which include low cost and a large variety of efficient adsorbents, the adsorption process represents a favorable way to reduce antibiotic contamination. This work theoretically investigated the adsorption of amoxicillin (AMO), ampicillin (AMP), and doripenem (DOR) onto raw bentonite (B) and its composite with chitosan (BC). Simulation studies using molecular dynamics were carried out to comprehend the interactions between these antibiotics and B and BC adsorbents between 30 and 50 °C, of which the interaction energies of −59.999, −59.279, and −66.877 kcal mol−1 were obtained for AMO/B, AMP/B, and DOR/B systems, respectively. Statistical physics models, i.e., the Gaussian Monolayer Multisite Model (GMMM) and Monolayer Model Coupled to Real Gas (MMRG) were also used to fit the experimental data with good results ( R 2 > 0.999). The findings indicated that the interactions between the chosen antibiotics and the adsorbents were mostly take place by Van der Waals forces (Non-bond energies of −20.442, −20.403, and −20.884 kcal mol−1 for AMO/B, AMP/B, and DOR/B systems, respectively), with multi-molecular (1 < n < 2.5) antibiotic adsorptions occurring primarily on both bentonite and BC. [ABSTRACT FROM AUTHOR]

CTX-M-15 type β-lactamase has the ability to hydrolyse cefotaxime, a third generation cephalosporin. The infections caused by multidrug resistant strains, especially CTX-M-15 producing strains are being treated with carbapenem group of β-lactam antibiotics. The objective of the study was to know if cefotaxime in combination with doripenem (carbapemen antibiotic) at very low concentration, inhibits the CTX-M-15 producing bacterial strains. blaCTX−M−15 gene was cloned to express CTX-M-15 enzyme and construct CTX-M-15 producing strain. The clone carrying CTX-M-15 was found susceptible to doripenem. Doripenem and CTX-M-15 binding was an endothermic and spontaneous process leading to change in polarity in the micro-environment and conformational changes of enzyme as shown by fluorescence, UV and CD spectroscopic study. The catalytic efficiency of CTX-M-15 enzyme was reduced to about 15.86% when it was treated with doripenem along with cefotaxime (in 5 times molar ratio each of doripenem and cefotaxime w.r.t CTX-M-15), as compared to the studies where enzyme's efficiency was increased by 33% when treated with cefotaxime alone. Hence, doripenem in combination with cefotaxime reduces enzyme's efficiency to hydrolyse cefotaxime by about 48%. FIC study showed that doripenem paired with cefotaxime showed synergistic effect against CTX-M-15 producing bacterial strain. The study concludes that doripenem at very low concentration (25 nM), induces such a structural changes in CTX-M-15 which reduced enzyme's activity to hydrolyse cefotaxime. Hence, the synergistic use of doripenem and cefotaxime plays a significant role in inhibiting the efficiency of CTX-M-15 type β-lactamase, and may provide an alternative approach to reduce the resistance against the cephalosporin type antibiotics.

Understanding antibiotic allergies and the risk of cross-sensitivity between and within antibiotic classes can have a substantial impact on patient care. The purpose of this review article is to provide insight into carbapenem allergies, describing the overall incidence, risk factors, and in-class cross-sensitivity. A PubMed search was conducted using the following search terms: carbapenem, allergy, cross-sensitivity, incidence, imipenem/cilastatin, meropenem, ertapenem, and doripenem. Article bibliographies and relevant drug monographs were also reviewed. The overall reported incidence of carbapenem allergy is 0.3%−3.7%. Risk of cross-sensitivity between penicillins and carbapenems is less than 1% in patients with a positive penicillin skin test. Data on cross-sensitivity between cephalosporins and carbapenems are limited; however, the risk appears to also be low. No clinical studies have described cross-sensitivity between the carbapenem agents thus far. The limited data available from case reports demonstrates a lack of cross-sensitivity between the individual carbapenems, suggesting that an alternative carbapenem may cautiously be used in patients with a reported carbapenem allergy.