Interference with antibiotic activity and its inactivation by bacterial modifying enzymes is a prevailing mode of bacterial resistance to antibiotics. Aminoglycoside antibiotics become inactivated by aminoglycoside-6′-N-acetyltransferase-Ib [AAC(6′)-Ib] of gram-negative bacteria which transfers an acetyl group from acetyl-CoA to the antibiotic. The aim of the study was to disrupt the enzymatic activity of AAC(6′)-Ib by adjuvants and restore aminoglycoside activity as a result. The binding affinities of several vitamins and chemical compounds with AAC(6′)-Ib of Escherichia coli, Klebsiella pneumoniae, and Shigella sonnei were determined by molecular docking method to screen potential adjuvants. Adjuvants having higher binding affinity with target enzymes were further analyzed in-vitro to assess their impact on bacterial growth and bacterial modifying enzyme AAC(6′)-Ib activity. Four compounds—zinc pyrithione (ZnPT), vitamin D, vitamin E and vitamin K-exhibited higher binding affinity to AAC(6′)-Ib than the enzyme’s natural substrate acetyl-CoA. Combination of each of these adjuvants with three aminoglycoside antibiotics—amikacin, gentamicin and kanamycin—were found to significantly increase the antibacterial activity against the selected bacterial species as well as hampering the activity of AAC(6′)-Ib. The selection process of adjuvants and the use of those in combination with aminoglycoside antibiotics promises to be a novel area in overcoming bacterial resistance.

Xanthine oxidase (XO) is a metalloflavoenzyme associated with the uric acid formation in purine metabolism. Serum XO has been suggested to be associated with liver and kidney dysfunction, diabetes and cardiovascular diseases. However, there is limited information on the relationship between serum XO levels and hypertension. This study aimed to assess the relationship between serum XO levels and hypertension in Bangladeshi adults. In this study, fasting blood samples were collected from 312 participants (225 males and 87 females), aged ≥ 20 years. Serum levels of XO were determined by ELISA and other biochemical parameters including serum uric acid (SUA) were measured by colorimetric methods. Hypertension was defined as SBP ≥ 140 mmHg and/or DBP ≥ 90 mmHg or self-reported recent use of anti-hypertensive medications. Association between serum XO levels and hypertension was evaluated by multinomial logistic regression analysis. The mean level of XO was significantly higher (p < 0.001) in females (5.8 ± 3.2 U/L) than in males (3.9 ± 2.5 U/L). When the participants were divided by blood pressure levels, the mean level of serum XO was significantly higher (p < 0.01) in the hypertensive group (5.0 ± 2.7 U/L) compared to the normotensive control group (4.0 ± 2.7 U/L). An increasing trend for SBP and DBP levels was observed across the XO quartiles (at least p < 0.01 for both cases). A significant positive correlation was found for XO with SBP and DBP (p < 0.01). In regression analysis, the serum levels of XO showed a significant and independent association with hypertension prevalence. In conclusion, the mean level of serum XO was significantly higher in hypertensive individuals and XO was independently associated with the prevalence of hypertension. Our results indicate that XO may have a potential role in the pathophysiology of elevated blood pressure through generating of reactive oxygen species. Further large-scale longitudinal studies are needed to determine the underlying mechanisms between XO and hypertension.