Targeting Bacterial Resistance: Rational Design and Evaluation of Antibiotic Combinations with Adjuvants

Antimicrobial resistance (AMR) has become a major global health concern, posing significant challenges to modern medicine. The diminishing pipeline of novel antimicrobial agents compounds the problem, as big pharmaceutical companies have reduced investments in this area. The rise of AMR has rendered traditional treatment approaches less effective, demanding the identification and development of new therapeutic options. Some bacteria employ enzymes to evade the effects of antimicrobial agents, such as FosA, which degrades fosfomycin, and NDM-1, which hydrolyzes carbapenems. These enzymes pose a critical concern as they target drugs with favorable spectra and are often considered last-resort treatment options. To combat AMR, rational drug design aims to develop compounds that inhibit the enzymes responsible for drug inactivation. Computer-aided drug discovery (CADD) techniques, including structure-based and ligand-based approaches, aid in identifying potential inhibitors. In Chapter 2, the study identifies baicalin, alendronate, risedronate, and zoledronate as FosA inhibitors. When combined with fosfomycin, these compounds demonstrate a reduction in the minimum inhibitory concentration (MIC) of fosfomycin and additive effects. Zoledronate shows the most promise as an adjuvant; however, the combination with fosfomycin exhibits a lower killing rate. Further investigation reveals that a chemical reaction occurred within the mixture, resulting in the degradation of fosfomycin, as confirmed by 31P NMR experiments. Chapter 3 explores the synergy between meropenem with bisphosphonates and various inhibitors against carbapenem-resistant E. coli and K. pneumoniae. The bisphosphonates demonstrated potentiation effects through NDM-1 enzyme inhibition, leading to increased bacterial susceptibility to meropenem. Alendronate and linezolid exhibited synergistic bactericidal activity when combined with meropenem against E. coli, while sutezolid showed promising results

Effect of Eleutherine americana Merr. bulb extract on blood pressure and heart rate in anesthetized hypertensive rats

The effect of ethanolic extract of Eleutherine americana Merr. on the blood pressure and heart rate has been investigated. A number of 25 Sprague-Dawley male rats were induced with prednisone 1.5 mg/kg in combination with saline solution 2.5% for 14 days to obtain hypertension model. The rats were anesthetized and prepared for the recording of blood pressure and heart rate. The rats were divided into five groups receiving 100, 200, and 400 mg/kg of the extract, vehicle control, and captopril 30 mg/kg as the reference. The treatment was administered three times with 30 minutes interval. The systolic (SBP), diastolic (DBP), mean arterial pressure (MAP), and heart rate (HR) were recorded. The data were analyzed with two-way analysis of variance (ANOVA) followed by Duncan’s MRT (95% confidence interval). The study revealed that the extract exhibited a blood pressure lowering effect. The best antihypertensive activity of the extract was shown by the dose of 100 mg/kg. Meanwhile, HR was also affected inversely by the treatment, in which the lowest dose caused the highest increase. The study suggests that the extract of Eleutherine americana exhibits antihypertensive activity that may be potential for future development of drugs. The effect of ethanolic extract of Eleutherine americana Merr. on the blood pressure and heart rate has been investigated. A number of 25 Sprague-Dawley male rats were induced with prednisone 1.5 mg/kg in combination with saline solution 2.5% for 14 days to obtain hypertension model. The rats were anesthetized and prepared for the recording of blood pressure and heart rate. The rats were divided into five groups receiving 100, 200, and 400 mg/kg of the extract, vehicle control, and captopril 30 mg/kg as the reference. The treatment was administered three times with 30 minutes interval. The systolic (SBP), diastolic (DBP), mean arterial pressure (MAP), and heart rate (HR) were recorded. The data were analyzed with two-way analysis of variance (ANOVA) followed by Duncan’s MRT (95% confidence interval). The study revealed that the extract exhibited a blood pressure lowering effect. The best antihypertensive activity of the extract was shown by the dose of 100 mg/kg. Meanwhile, HR was also affected inversely by the treatment, in which the lowest dose caused the highest increase. The study suggests that the extract of Eleutherine americana exhibits antihypertensive activity that may be potential for future development of drugs.

Comparative Effectiveness of Defatted Hypotensive Crude Extract, Ethyl Acetate and Butanolic Fractions of Cassytha filiformis L. on Different Models of Hypertensive Rats

The hypotensive effectiveness of defatted crude ethanolic extract, ethyl acetate and butanolic fractions of Cassytha filiformis L. have been compared on anesthesized prednisone-saline-induced (PN) and Prednisone-saline-LNAME -induced (PNL) hypertensive rats. Extract/fractions were given at the dose of 5 mg/kg each while a group treated by 100 μmol/kg oftempol was used as comparison. Extract/fractions/vehicle were commence in 3 consecutive doses intravenously every one hour interval. The systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP) and heart rate (HR) of the animals were measured (Biopac® MP 150 Data Acquisition System). Data were presented as the percentage changes of those parameters and analyzed by three way ANOVA followed by Duncan’s Multiple Range Test. Results showed that the ethanolic defatted extract and tempol decreased animal SBP, DBP, MAP and HR significantly (p0.1). The average percentage decrease of animal SBP and MAP on PNL rats were higher (p0.1). Repeated dose of all samples tent to decrease animal SBP and HR (p0.1). These results indicated that the hypotensive effectiveness of the defatted ethanolic extract of Cassytha filiformis is better as compared to its ethyl acetate and butanolic fractions and these effects are greater on oxidative stress related hypertensive rats

Evaluation of Parents’ Adherence in Giving Antibiotics on Respiratory Tract Infections (RTI) and Factors Associated with Adherence

Parents’ adherence in giving antibiotics plays an important role in therapeutic management of pediatric patients with respiratory tract infections and can avoid antibiotic resistance. The aims of this research are to evaluate parents’ adherence in giving antibiotic and factors associated with adherence. This research is conducted involving respondents from a primary health care center in Andalas, Padang who attended during April to August 2015. Adherence measurement has been done using pill counting method and MMAS (Morisky Medication Adherence Scale) containing 4 questions. By pill counting method, 43 respondents (65.15%) were found to be adherent in giving the antibiotic and 23 respondents (34.85%) were not. Assessment adherence using MMAS obtained 23 respondents (34.85%) had a high adherence, 31 respondents (46.97%) had a medium adherence, and 12 respondents (18.18%) had a low adherence. In this research, respondents are categorized as adherent if the rest of the antibiotics up to 20% and a score of MMAS are 0. Statistical analysis using Chi-square test, Fisher test and Kolmogorov-Smirnov have been done to investigate respondent and patient characteristic, and parents or patients habit factor associated with adherence. It can be concluded that from 66 recruited respondents, 23 respondents (34.85%) were adhere in giving antibiotic to patients. Factors associated with adherence are busy respondent, forgetful, patient seemed to recover, and patient cannot swallow

Antihypertensive and antioxidant activity of Cassytha filiformis L.: A correlative study

Objective: To study the blood pressure lowering effect of Cassytha filiformis extract in animal models of hypertension and its correlation with the antioxidant activity. Methods: Male Sprague–Dawley rats were divided into two groups: endocrine hypertension (HTN group) that received a combination of prednisone and salt for two weeks and oxidative stress-associated hypertension (HTN-OS group) that received additional induction of l-Nitro Arginine Methyl Esther (l-NAME) for two days. Each group was subdivided into 4 and treated intravenously with the extract 5; 10; and 20 mg/kg, and vehicle control. The systolic blood pressure (SBP), diastolic blood pressure (DBP), and mean arterial pressure (MAP) were recorded. The blood was taken before and at the end of recording for the measurement of serum concentration of nitric oxide (NO). The changes of blood pressure were analyzed by two-way ANOVA while its correlation with NO concentration was analyzed by Pearson's Correlation. Results: The study showed a significant antihypertensive effect of the extract as compared with control group (P 0.05). Conclusions: The study concludes that C. filiformis extract in the dose of 5 mg/kg exhibits the best blood pressure lowering effect in both animal models. Antihypertensive activity of the extract is not correlated with its antioxidant effect

PHARMACODYNAMICS EFFECT OF METHYLPREDNISOLONE TABLETS ON THE SERUM CONCENTRATION OF ANNEXIN A1: IN VIVO COMPARATIVE STUDY BETWEEN GENERIC AND INNOVATOR DRUG

Objective: The aims of this study were to investigate the comparative pharmacodynamics effect of methylprednisolone (MP) innovator, MP branded generic, and MP generic products to the serum concentration of annexin A1 (AnxA1).Methods: It was conducted by two-way crossover design in male rabbits. AnxA1 was measured at 0, 0.5, 1, 2, 3, 5, 7, and 9 h after the administration of the drugs. The peak concentration (Cmax), the time at which the peak concentration was achieved (Tmax), and the area under the plasma concentration-time curve (AUC) were also determined.Results: The highest concentration and widest AUC of AnxA1 were obtained in MP innovator drug. MP innovator and branded generic reaches the peak time (Tmax) at the third 3rd h, while the MP generic reaches the peak time at the 5th h. The results showed that there was no significant difference in the serum concentration of AnxA1 between MP tablets after analyzed with a one-way analysis of variance.Conclusion: It could be concluded that the innovator drug of MP tablet gave the same effect on the serum concentration of AnxA1 than its generic counterparts, but an onset of action MP innovator and branded generic is faster than the generic product

ANTIBACTERIAL RESISTANCE PATTERN OF PSEUDOMONAS AERUGINOSA ISOLATED FROM CLINICAL SAMPLES AT A GENERAL HOSPITAL IN PADANG, WEST SUMATRA, INDONESIA

Objectives: Pseudomonas aeruginosa is an opportunistic pathogen that has an innate resistance to some antibiotics. This bacterium is one of the mostcommon causes of nosocomial infections that include surgical wound infections, burns, and urinary tract infections. The bacteria have been reportedlyresistant to many antibiotics and have developed multidrug resistance (MDR). The objective of the study was to determine the resistance pattern ofP. aeruginosa isolated from clinical samples of patients against some major antibiotics.Methods: Isolates of P. aeruginosa were obtained from clinical sample of urine, sputum, swabs, pus, feces, and blood and cultured in cetrimide agar. P.aeruginosa ATCC 27853 was used as a positive control. The antibacterial susceptibility testing was conducted against 13 antibiotics: Ceftazidime, cefotaxime,ceftriaxone, cefoperazone, ciprofloxacin, levofloxacin, ofloxacin, gentamicin, amikacin, piperacillin, ticarcillin, meropenem, and imipenem. The examinationwas carried out using agar diffusion method of Kirby-Bauer and following the standards from Clinical and Laboratory Standards Institute (CLSI).Results: The results showed that bacterial resistance was established against all tested antibiotics. The highest number of resistance was shownagainst ceftriaxone (44.21%), whereas the most susceptibility was exhibited against amikacin (only 9.47% of resistance). MDR P. aeruginosa (MDRPA)was detected on almost all clinical samples tested, except the feces. The sample with the highest percentage of MDRPA was the pus.Conclusion: The study concludes that the most effective antibiotic against P. aeruginosa is amikacin (91.51%), whereas the most resistance is exhibited to ceftriaxone (43.16%)