scholarly journals 1390. Durlobactam, a Diazabicyclooctane (DBO) β-lactamase Inhibitor (BLI), Inhibits BlaC and Peptidoglycan (PG) Transpeptidases of Mycobacterium tuberculosis (Mtb): A Novel Approach to Therapeutics for Tuberculosis (TB)?

2021 ◽  
Vol 8 (Supplement_1) ◽  
pp. S780-S780
Author(s):  
David Nguyen ◽  
Christopher Bethel ◽  
Magdalena A Taracilla ◽  
Qing Li ◽  
Khalid M Dousa ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Therapeutic Potential ◽  
Multidrug Resistant ◽  
Research Support ◽  
K Value ◽  
Mycobacterium Tuberculosis H37rv ◽  
Microdilution Method ◽  
Novel Approach ◽  
Dual Action ◽  
Km Value

Abstract Background Novel therapies for multidrug-resistant TB are needed and new BLIs could answer this call. Mtb encodes for BlaC, a class A β-lactamase. BlaC is inhibited by clavulanate (CLA) while the DBO avibactam (AVI) is an inefficient inhibitor (low k2/K value). Carbapenems are hydrolyzed slowly by BlaC (low kcat/Km value) making them “dual action” compounds that inhibit both BlaC and PG transpeptidases, the intended β-lactam targets. DBOs inhibit PG transpeptidases in other bacteria. To explore the therapeutic potential of new DBOs against Mtb, we compared the inhibitor activity of AVI, relebactam (REL), and durlobactam (DUR, formerly ETX2514) against BlaC and Mtb PG transpeptidases using a biochemical approach. We also investigated the ability of DUR to lower minimum inhibitory concentrations (MICs) of β-lactams against Mtb H37Rv. Methods Mass spectrometry was performed to capture acyl-enzyme complexes (AECs) of purified BlaC and PG transpeptidases (PonA1, LdtMt1, LdtMt2, LdtMt3, and LdtMt5) with β-lactams and BLIs. Steady-state enzyme kinetics were determined using nitrocefin as a substrate. MICs with amoxicillin (AMX), meropenem (MER), CLA, and DUR alone and in combination against Mtb H37Rv were assessed using a microdilution method. Results DUR alone had a MIC of 2 µg/mL with Mtb H37Rv (Table 1). BlaC formed AECs with all carbapenems and BLIs. BlaC had lower Ki app and higher k2/K with DUR than those with AVI and REL and comparable to those with CLA; however, with a period of pre-incubation, AVI fully inhibits BlaC (Table 2). The carbapenems and DUR formed the most AECs with PG transpeptidases of the β-lactams and BLIs respectively; PG transpeptidases had lower Ki app values with DUR than those with AVI (Table 3). Table 1. Minimum Inhibitory Concetrations for Mycobacterium tuberculosis H37Rv Conclusion DUR alone has some antimicrobial activity against Mtb H37Rv. The likely mechanism that underlies this activity is inhibition of BlaC and several PG transpeptidases. Inhibition of enzyme targets with DUR was more potent and efficient than AVI and REL. DUR in combination with β-lactams lowered MICs but the DUR concentration used was higher than its MIC. Our findings support the exploration of novel BLIs against BlaC and PG transpeptidases with the ultimate goal of repurposing these drugs for the treatment of TB. Disclosures Robert A. Bonomo, MD, entasis (Research Grant or Support)Merck (Grant/Research Support)NIH (Grant/Research Support)VA Merit Award (Grant/Research Support)VenatoRx (Grant/Research Support)

scholarly journals ANTITUBERCULOSIS ACTIVITY OF EXTRACT AND FRACTIONS OF TINOSPORA CRISPA AGAINST MYCOBACTERIUM TUBERCULOSIS H37RV USING MYCOBACTERIA GROWTH INDICATOR TUBE AND AGAR PROPORTION METHOD

2018 ◽  
Vol 11 (3) ◽  
pp. 132
Author(s):  
Retno Wahyuningrum ◽  
Ritmaleni Ritmaleni ◽  
Tatang Irianti ◽  
Subagus Wahyuono ◽  
Takushi Kaneko
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Ethanolic Extract ◽  
Multidrug Resistant ◽  
Drug Candidates ◽  
Mycobacterium Tuberculosis H37rv ◽  
Indicator Tube ◽  
Resistant Tuberculosis ◽  
Lowenstein Jensen ◽  
Proportion Method ◽  
Growth Indicator

 Objective: The increasing incidence of multidrug-resistant tuberculosis (TB) has created a need to discover a new anti-TB drug candidates. The aim of this study was to screen extract and fractions of Tinospora crispa for activity against Mycobacterium tuberculosis H37Rv.Methods: The dried and pulverized T. crispa stem was extracted by maceration method using ethanol (96%). The anti-TB activity was carried out using mycobacteria growth indicator tube (MGIT) system and agar proportion method with Lowenstein–Jensen (LJ) medium.Result: The result of this study showed that ethanolic extract and fractions of T. Crispa did not exhibit anti-TB activity in the range of 100–1000 μg/ml with MGIT method, while with agar proportion method, there were M. tuberculosis colonies growth on the LJ containing 1000 μg/ml extract slants.Conclusion: The tested extract and fractions of T. crispa have no anti-TB activity against M. tuberculosis until 1000 μg/ml.

Design, Synthesis and Antitubercular Evaluation of New Benzimidazole Scaffolds

2021 ◽  
Vol 18 (4) ◽  
pp. 375-383
Author(s):  
Smriti Yadav ◽  
Bharath Kumar Inturi ◽  
Shrinidhi B.R ◽  
Pooja H.J ◽  
Neenu Ganesh ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Cell Lines ◽  
Normal Cell ◽  
Acyl Carrier Protein ◽  
Antitubercular Activity ◽  
Resistance Mechanisms ◽  
Docking Studies ◽  
Chemical Library ◽  
Activity Data ◽  
Mycobacterium Tuberculosis H37rv

Background: To overcome one of the resistance mechanisms of Isoniazid (INH), there is a need for an antitubercular agent that can inhibit InhA enzyme by circumventing the formation of INH-NAD+ adduct. Objective: The objective of the study is the development of novel antitubercular agents that target Mycobacterium tuberculosis InhA (Enoyl Acyl Carrier Protein Reductase). Methods: A small-molecule chemical library was used for the identification of the novel InhA inhibitors using primary screening and molecular docking studies followed by the scaffold hopping approach. The designed molecules, 2-(2-(hydroxymethyl)-1H- benzo[d] imidazole-1-yl)- N- substituted acetamides were synthesized by reacting (1H- benzo[d]imidazole -2-yl)methanol with appropriate 2-chloro-N-substituted acetamides / dialkylamino carbonyl chlorides respectively in good yields (42-65%). The antitubercular activity of synthesized compounds was determined by Microplate Alamar Blue Assay (MABA) against Mycobacterium tuberculosis H37Rv strain. The selected compounds were screened for cytotoxicity on normal cell lines. Results: The antitubercular activity data revealed that the 4-chlorophenyl substituted derivative (3b) showed good MIC value at 6.25 μg/mL and, dimethylacetamide substituted derivative (3i) showed MIC at 25 μg/mL among the tested compounds. The substitution of dimethylacetamide (3i) group on the 1st position of benzimidazole has good antitubercular activity (25μg/mL) in comparison to the diethyl acetamide group (3j, 100μg/mL). Conclusion: The antitubercular activity data indicated that the tested compounds exhibited well to moderate inhibition of the H37Rv strains. The compounds (3b) with electronegative substitution on the phenyl moiety exhibited better antitubercular activity than that of the other substitutions. The active compounds have displayed a good safety profile on normal cell lines.

scholarly journals Proteomic analysis of drug-susceptible and multidrug-resistant nonreplicating Beijing strains of Mycobacterium tuberculosis cultured in vitro

2021 ◽  
Vol 26 ◽  
pp. 100960
Author(s):  
Bhanubong Saiboonjan ◽  
Sittiruk Roytrakul ◽  
Arunnee Sangka ◽  
Viraphong Lulitanond ◽  
Kiatichai Faksri ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Proteomic Analysis ◽  
Multidrug Resistant

scholarly journals Analysis of drug resistance and mutation profiles in Mycobacterium tuberculosis isolates in a surveillance site in Beijing, China

2021 ◽  
Vol 49 (1) ◽  
pp. 030006052098493
Author(s):  
Jie Zhang ◽  
Yixuan Ren ◽  
Liping Pan ◽  
Junli Yi ◽  
Tong Guan ◽  
...  
Keyword(s):  
Drug Resistance ◽  
Mycobacterium Tuberculosis ◽  
Drug Testing ◽  
Multidrug Resistant ◽  
High Rate ◽  
Drug Resistant ◽  
Surveillance Site ◽  
Mdr Tb ◽  
Previously Treated Patients ◽  
Beijing China

Objective This study analyzed drug resistance and mutations profiles in Mycobacterium tuberculosis isolates in a surveillance site in Huairou District, Beijing, China. Methods The proportion method was used to assess drug resistance profiles for four first-line and seven second-line anti-tuberculosis (TB) drugs. Molecular line probe assays were used for the rapid detection of resistance to rifampicin (RIF) and isoniazid (INH). Results Among 235 strains of M. tuberculosis, 79 (33.6%) isolates were resistant to one or more drugs. The isolates included 18 monoresistant (7.7%), 19 polyresistant (8.1%), 28 RIF-resistant (11.9%), 24 multidrug-resistant (MDR) (10.2%), 7 pre-extensively drug-resistant (XDR, 3.0%), and 2 XDR strains (0.9%). A higher rate of MDR-TB was detected among previously treated patients than among patients with newly diagnosed TB (34.5% vs. 6.8%). The majority (62.5%) of RIF-resistant isolates exhibited a mutation at S531L in the DNA-dependent RNA polymerase gene. Meanwhile, 62.9% of INH-resistant isolates carried a mutation at S315T1 in the katG gene. Conclusion Our results confirmed the high rate of drug-resistant TB, especially MDR-TB, in Huairou District, Beijing, China. Therefore, detailed drug testing is crucial in the evaluation of MDR-TB treatment.

scholarly journals 1608. Efficacy of Ceftolozane/Tazobactam for Multidrug-Resistant Gram-Negative Infections in Multiple Urban Hospitals

2020 ◽  
Vol 7 (Supplement_1) ◽  
pp. S798-S799
Author(s):  
Nicolo Cabrera ◽  
Truc T Tran ◽  
Travis J Carlson ◽  
Faris Alnezary ◽  
William R Miller ◽  
...  
Keyword(s):  
Research Study ◽  
Clinical Success ◽  
Significant Proportion ◽  
Scientific Research ◽  
Panel Member ◽  
Multidrug Resistant ◽  
Outcome Data ◽  
Research Support ◽  
Gram Negative ◽  
Study Investigator

Abstract Background Ceftolozane/tazobactam (C/T) is a novel cephalosporin/beta-lactamase inhibitor combination developed for use against multidrug-resistant (MDR) Gram-negative infections, particularly Pseudomonas aeruginosa (PA). C/T is approved for complicated urinary tract and intraabdominal infections as well as hospital-acquired/ventilator-associated bacterial pneumonias. However, comprehensive clinical characterization of patients treated with C/T in non-FDA-approved indications is limited. Methods Patients ≥18 years who received C/T for ≥48 hours while hospitalized in 9 acute care centers in Houston, TX from January 2016 through September 2018 were included. Demographic, microbiologic, treatment and clinical outcome data were retrospectively collected by chart review. In patients who received multiple inpatient courses of C/T, only the first course with C/T was assessed. Results 210 patients met inclusion criteria: 58% were non-white, 35% were female and 13% were immunocompromised. Median age was 61 years (IQR, 48 to 69). Median Charlson comorbidity index was 5 (IQR, 2 to 6). At the onset of the index episode, a significant proportion of patients required intensive care unit admission (44%), mechanical ventilation (37%) and pressor support (22%). Respiratory sources were the most common (50%) followed by urine (15%). Positive cultures were documented in 93% of the cases and PA was found in 86%. Majority (95%) of PA which were MDR. C/T use was guided by susceptibility testing of the index isolate in ca. 52%. In 5.7% of cases, C/T was used to escalate therapy without any documented C/T-susceptible organism. Half (51%) of the cohort received initial dosing appropriate for renal function while 36% receiving a lower than recommended dose. Clinical success (i.e., recovery from infection-related signs and symptoms) occured in 77%. The in-hospital mortality rate in our cohort was 15% with 26 of 31 deaths deemed infection-related. Conclusion We report a large multicenter observational cohort that received C/T. A 77% clinical success with the use of C/T was documented. These data support the use of C/T in critically ill patients infected with MDR PA. Disclosures William R. Miller, MD, Entasis Therapeutics (Scientific Research Study Investigator)Merck (Grant/Research Support)Shionogi (Advisor or Review Panel member) Laura A. Puzniak, PhD, Merck (Employee) Cesar A. Arias, MD, MSc, PhD, FIDSA, Entasis Therapeutics (Scientific Research Study Investigator)MeMed (Scientific Research Study Investigator)Merck (Grant/Research Support)

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