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Antibiotics (Basel, Switzerland) Dec 2023The emergence of bacteria resistant to beta-lactam/beta-lactamase inhibitor combinations is insufficiently studied, wherein the role of the inoculum effect (IE) in...
Pharmacodynamics of Doripenem Alone and in Combination with Relebactam in an In Vitro Hollow-Fiber Dynamic Model: Emergence of Resistance of Carbapenemase-Producing and the Inoculum Effect.
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 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 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.
PubMed: 38136739
DOI: 10.3390/antibiotics12121705 -
Journal of Infection in Developing... Nov 2023Increased carbapenem resistance in Klebsiella spp. strains causes high morbidity and mortality. The genes encoded for carbapenemaseare transferrable between different...
INTRODUCTION
Increased carbapenem resistance in Klebsiella spp. strains causes high morbidity and mortality. The genes encoded for carbapenemaseare transferrable between different bacterial species. In the present study, we aimed to investigate carbapenem resistance genes in Klebsiella spp. strains.
METHODOLOGY
Fifty Klebsiella spp. strains were isolated from rectal swabs of patients hospitalized in the neonatal intensive care unit (NICU). All strains were identified with API20E. The minimum inhibitory concentrations (MICs) of carbapenems were determined by the broth dilution method. The major five carbapenem genes (OXA-48, NDM, VIM, KPC, and IMP) were detected by the multiplex real-time PCR method.
RESULTS
It was found that 49 (98%) of the strains were resistant to ertapenem (MIC ≥ 2μg/mL) and imipenem(MIC ≥ 4 μg/mL), and 47 (94%) of the strains were resistant to doripenem (MIC ≥ 4 μg/mL)and meropenem(MIC ≥ 4 μg/mL).NDM was detected in 42%, OXA-48 in 16%, and VIM in one (2%) isolate, and NDM + OXA-48 co-existed in 36% of the isolates. The KPC and IMP genes were not detected.
CONCLUSIONS
NDM and NDM co-existing with OXA-48 were prevalent in the NICU of Istanbul Medical Faculty Hospital. Paying attention to the hand hygiene of healthcare workers, screening of rectal swabs of hospitalized patients for the presence of carbapenem resistance strains, and isolation of infected patients can effectively control the spread of carbapenem-resistant strains.
Topics: Infant, Newborn; Humans; Carbapenems; Anti-Bacterial Agents; Klebsiella; Real-Time Polymerase Chain Reaction; Prevalence; beta-Lactamases; Klebsiella pneumoniae; Microbial Sensitivity Tests; Bacterial Proteins
PubMed: 38064404
DOI: 10.3855/jidc.17892 -
Research Square Sep 2023During head and neck cancer treatment, off-target ionizing radiation damage to the salivary glands commonly causes a permanent loss of secretory function. Due to the...
During head and neck cancer treatment, off-target ionizing radiation damage to the salivary glands commonly causes a permanent loss of secretory function. Due to the resulting decrease in saliva production, patients have trouble eating, speaking and are predisposed to oral infections and tooth decay. While the radioprotective antioxidant drug Amifostine is FDA approved to prevent radiation-induced hyposalivation, it has intolerable side effects that limit its use, motivating the discovery of alternative therapeutics. To address this issue, we previously developed a salivary gland mimetic (SGm) tissue chip platform. Here, we leverage this SGm tissue chip for high-content drug discovery. First, we developed in-chip assays to quantify glutathione and cellular senescence (β-galactosidase), which are biomarkers of radiation damage, and we validated radioprotection using WR-1065, the active form of Amifostine. Other reported radioprotective drugs including Edaravone, Tempol, N-acetylcysteine (NAC), Rapamycin, Ex-Rad, and Palifermin were also tested to validate the ability of the assays to detect cell damage and radioprotection. All of the drugs except NAC and Ex-Rad exhibited robust radioprotection. Next, a Selleck Chemicals library of 438 FDA-approved drugs was screened for radioprotection. We discovered 25 hits, with most of the drugs identified exhibiting mechanisms of action other than antioxidant activity. Hits were down-selected using EC50 values and pharmacokinetic and pharmacodynamic data from the PubChem database. This led us to test Phenylbutazone (anti-inflammatory), Enoxacin (antibiotic), and Doripenem (antibiotic) for in vivo radioprotection in mice using retroductal injections. Results confirm that Phenylbutazone and Enoxacin exhibited radioprotection equivalent to Amifostine. This body of work demonstrates the development and validation of assays using a SGm tissue chip platform for high-content drug screening and the successful in vitro discovery and in vivo validation of novel radioprotective drugs with non-antioxidant primary indications pointing to possible, yet unknown novel mechanisms of radioprotection.
PubMed: 37790388
DOI: 10.21203/rs.3.rs-3246405/v1 -
Microorganisms Aug 2023The emergence of carbapenem-resistant Enterobacterales (CRE) has been recognized as a significant concern globally. Ceftazidime/avibactam (CZA) is a novel...
The emergence of carbapenem-resistant Enterobacterales (CRE) has been recognized as a significant concern globally. Ceftazidime/avibactam (CZA) is a novel β-lactam/β-lactamase inhibitor that has demonstrated activity against isolates producing class A, C, and D β-lactamases. Here-in, we evaluated the in vitro activity of CZA and comparator antimicrobial agents against 858 CRE isolates, arising from the Southeast Asian region, collected from a large tertiary hospital in Singapore. These CRE isolates mainly comprised (50.5%), (29.4%), and complex (17.1%). Susceptibility rates to levofloxacin, imipenem, meropenem, doripenem, aztreonam, piperacillin/tazobactam, cefepime, tigecycline, and polymyxin B were low. CZA was the most active β-lactam agent against 68.9% of the studied isolates, while amikacin was the most active agent among all comparator antibiotics (80% susceptibility). More than half of the studied isolates (51.4%) identified were carbapenemase (KPC)-2 producers, 25.9% were New Delhi metallo-β-lactamase (NDM) producers, and Oxacillinase (OXA)-48-like producers made up 10.7%. CZA was the most active β-lactam agent against KPC-2, OXA-48-like, and Imipenemase (IMI) producers (99.3% susceptible; MIC: ≤1/2 mg/L). CZA had excellent activity against the non-carbapenemase-producing CRE (91.4% susceptible; MIC: ≤1/8 mg/L). Expectedly, CZA had no activity against the metallo-β-lactamases (MBL)-producing CRE (NDM- and Imipenemase MBL (IMP) producers; 27.2% isolates), and the carbapenemase co-producing CRE (NDM + KPC, NDM + OXA-48-like, NDM + IMP; 3.0% isolates). CZA is a promising addition to our limited armamentarium against CRE infections, given the reasonably high susceptibility rates against these CRE isolates. Careful stewardship and rational dosing regimens are required to preserve CZA's utility against CRE infections.
PubMed: 37764002
DOI: 10.3390/microorganisms11092158 -
International Journal of Molecular... Sep 2023In this study, we established a novel capillary electrophoresis method for monitoring the concentration of doripenem in human plasma. As a time-dependent antibiotic,...
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 (NaHPO, pH 2.5) and 20% methanol. A large sample plug prepared in a low-conductivity phosphate buffer (50 mM NaHPO, 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 (r > 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.
PubMed: 37762057
DOI: 10.3390/ijms241813751 -
Microbiology Spectrum Sep 2023Two novel variants of carbapenemase (KPC) associated with resistance to ceftazidime-avibactam (CZA) and designated as KPC-113 and KPC-114 by NCBI were identified in...
Two novel variants of carbapenemase (KPC) associated with resistance to ceftazidime-avibactam (CZA) and designated as KPC-113 and KPC-114 by NCBI were identified in 2020, in clinical isolates of in Brazil. While of ST16 harbored the variant on an IncFII-IncFIB plasmid, of ST11 carried the variant on an IncN plasmid. Both isolates displayed resistance to broad-spectrum cephalosporins, β-lactam inhibitors, and ertapenem and doripenem, whereas producing KPC-114 showed susceptibility to imipenem and meropenem. Whole-genome sequencing and analysis revealed that KPC-113 presented a Gly insertion between Ambler positions 264 and 265 (R264_A265insG), whereas KPC-114 displayed two amino acid insertions (Ser-Ser) between Ambler positions 181 and 182 (S181_P182insSS) in KPC-2, responsible for CZA resistance profiles. Our results confirm the emergence of novel KPC variants associated with resistance to CZA in international clones of circulating in South America. IMPORTANCE KPC-2 carbapenemases are endemic in Latin America. In this regard, in 2018, ceftazidime-avibactam (CZA) was authorized for clinical use in Brazil due to its significant activity against KPC-2 producers. In recent years, reports of resistance to CZA have increased in this country, limiting its clinical application. In this study, we report the emergence of two novel KPC-2 variants, named KPC-113 and KPC-114, associated with CZA resistance in strains belonging to high-risk clones ST11 and ST16. Our finding suggests that novel mutations in KPC-2 are increasing in South America, which is a critical issue deserving active surveillance.
PubMed: 37671877
DOI: 10.1128/spectrum.00374-23 -
Journal of Infection and Public Health Oct 2023Enterobacterales carrying bla represent an emerging challenge in treating infectious diseases. In this study, we aimed to investigate the characteristics of...
BACKGROUND
Enterobacterales carrying bla represent an emerging challenge in treating infectious diseases. In this study, we aimed to investigate the characteristics of bla-producing Enterobacterales from three hospitals in southern Taiwan.
METHODS
Enterobacterales strains that were nonsusceptible to more than one carbapenem (ertapenem, meropenem, imipenem, or doripenem) were collected from hospitalized patients. Molecular typing for New Delhi metallo-β-lactamase (NDM) and antibiotic susceptibility tests were performed, followed by multilocus sequence typing (MLST), pulsed-field gel electrophoresis (PFGE), and plasmid analysis by PCR-based replicon typing.
RESULTS
A total of 1311 carbapenem-nonsusceptible Enterobacterales were isolated from 2017 to 2021. bla-encoding genes were detected in 108 isolates, with 53 (49.1%) harboring bla and 55 (50.9%) harboring bla. The rate of bla detection among isolates decreased to 2% in 2021. However, the rate of E. coli harboring bla increased from 1% to 12% of total isolates during the study period. Of 47 NDM-5-positive E. coli isolates, 44 (93.6%) were ST8346 with high genetic relatedness. E. coli ST8346 isolates showed high-level resistance to both carbapenems and aminoglycosides. Most (38 out of 47, 80.9%) bla-harboring E. coli isolates co-harbored bla. We analyzed the regions harboring bla in E. coli ST8346 via PCR amplification. bla and bla were located on two separate plasmids, IncF and IncX3, respectively.
CONCLUSION
The dissemination of E. coli ST8346 caused an increase in bla and bla co-harboring Enterobacterales in southern Taiwan, which show high-level resistance to both carbapenems and aminoglycosides. We identified a distinct IncF plasmid encoding bla that has the potential for rapid spread and needs further surveillance.
Topics: Humans; Escherichia coli; Multilocus Sequence Typing; Taiwan; Anti-Bacterial Agents; Carbapenems; Aminoglycosides
PubMed: 37633229
DOI: 10.1016/j.jiph.2023.08.007 -
Antibiotics (Basel, Switzerland) Jul 2023() is an opportunistic bacteria responsible for many nosocomial and community-acquired infections. The emergence and spread of antibiotic resistances have resulted in...
() is an opportunistic bacteria responsible for many nosocomial and community-acquired infections. The emergence and spread of antibiotic resistances have resulted in widespread epidemics and endemic dissemination of multidrug-resistant pathogens. A total of 145 isolates were recovered from hospital wastewater effluents and subjected to antibiogram profiling. Furthermore, the antibiotic resistance determinants were assessed among phenotypic resistant isolates using polymerase chain reaction (PCR). The isolates showed a wide range of antibiotic resistance against 21 selected antibiotics under 11 classes, with the most susceptible shown against imipenem (94.5%) and the most resistant shown against ampicillin (86.2%). The isolates also showed susceptibility to piperacillin/tazobactam (89.0%), ertapenem (87.6%), norfloxacin (86.2%), cefoxitin (86.2%), meropenem (76.6%), doripenem (76.6%), gentamicin (76.6%), chloramphenicol (73.1%), nitrofurantoin (71.7%), ciprofloxacin (79.3%), amikacin (60.7%), and amoxicillin/clavulanic acid (70.4%). Conversely, resistance was also recorded against tetracycline (69%), doxycycline (56.6%), cefuroxime (46.2%), cefotaxime (48.3%), ceftazidime (41.4%). Out of the 32 resistance genes tested, 28 were confirmed, with [ (58.8%), (47.89%), (25.2%), (5.9%)], [ (68.4%), (66.6%)], and [ (62.3%), (26%), (14.4%)] genes having the highest occurrence. Strong significant associations exist among the resistance determinants screened. About 82.7% of the isolates were multidrug-resistant (MDR) with a multiple antibiotics resistance index (MARI) range of 0.24 to 1.0. A dual presence of the resistant genes among was also observed to occur more frequently than multiple presences. This study reveals a worrisome presence of multidrug-resistant isolates and resistance genes in hospital waste effluent, resulting in higher public health risks using untreated surface water for human consumption. As a result, adequate water treatment and monitoring initiatives designed to monitor antimicrobial resistance patterns in the aquatic ecosystem are required.
PubMed: 37508235
DOI: 10.3390/antibiotics12071139 -
Antibiotics (Basel, Switzerland) Jun 2023The emergence of multidrug-resistance (MDR)-New Delhi metallo-beta-lactamase (NDM)-producing microorganisms-has become a serious concern for treating such infections....
The emergence of multidrug-resistance (MDR)-New Delhi metallo-beta-lactamase (NDM)-producing microorganisms-has become a serious concern for treating such infections. Therefore, we investigated the effective antimicrobial combinations against multidrug-resistant New Delhi metallo-beta-lactamase-producing strains of . The tests were carried out using the 2D(two-dimensional) checkerboard method. Of 7 antimicrobials, i.e., doripenem (DRP), streptomycin (STR), cefoxitin (FOX), imipenem (IPM), cefotaxime (CTX), meropenem (MER), and gentamicin (GEN), 19 different combinations were used, and out of them, three combinations showed synergistic effects against 31 highly drug-resistant strains carrying and other associated resistance markers. Changes in the minimum inhibitory concentration (MIC) values were interpreted using the test fractional inhibitory concentration index (FIC Index). The FIC Index values of these combinations were found in the range of 0.1562 to 0.5, which shows synergy, whereas no synergism was observed in the remaining antimicrobial combinations. We conclude that these antibiotic combinations can be analyzed in in vivo and pharmacological studies to establish an effective therapeutic approach.
PubMed: 37508229
DOI: 10.3390/antibiotics12071134 -
BioRxiv : the Preprint Server For... Jul 2023During head and neck cancer treatment, off-target ionizing radiation damage to the salivary glands commonly causes a permanent loss of secretory function. Due to the...
During head and neck cancer treatment, off-target ionizing radiation damage to the salivary glands commonly causes a permanent loss of secretory function. Due to the resulting decrease in saliva production, patients have trouble eating, speaking and are predisposed to oral infections and tooth decay. While the radioprotective antioxidant drug Amifostine is approved to prevent radiation-induced hyposalivation, it has intolerable side effects that limit its use, motivating the discovery of alternative therapeutics. To address this issue, we previously developed a salivary gland mimetic (SGm) tissue chip platform. Here, we leverage this SGm tissue chip for high-content drug discovery. First, we developed in-chip assays to quantify glutathione and cellular senescence (β-galactosidase), which are biomarkers of radiation damage, and we validated radioprotection using WR-1065, the active form of Amifostine. Following validation, we tested other reported radioprotective drugs, including, Edaravone, Tempol, N-acetylcysteine (NAC), Rapamycin, Ex-Rad, and Palifermin, confirming that all drugs but NAC and Ex-Rad exhibited robust radioprotection. Next, a Selleck Chemicals library of 438 FDA-approved drugs was screened for radioprotection. We discovered 25 hits, with most of the drugs identified with mechanisms of action other than antioxidant activity. Hits were down-selected using EC values and pharmacokinetics and pharmacodynamics data from the PubChem database leading to testing of Phenylbutazone (anti-inflammatory), Enoxacin (antibiotic), and Doripenem (antibiotic) for radioprotection in mice using retroductal injections. Results confirm that Phenylbutazone and Enoxacin exhibited equivalent radioprotection to Amifostine. This body of work demonstrates the development and validation of assays using a SGm tissue chip platform for high-content drug screening and the successful discovery and validation of novel radioprotective drugs with nonantioxidant primary indications pointing to possible, yet unknown novel mechanisms of radioprotection.
PubMed: 37503292
DOI: 10.1101/2023.07.12.548707