In vitro evaluation of the antibacterial activity of amitriptyline and its synergistic effect with ciprofloxacin, sulfamethoxazole–trimethoprim, and colistin as an alternative in drug repositioning

Non-Antibiotic Drug Repositioning as an Alternative Antimicrobial Approach

The worldwide scenario of antibiotic resistance and the falling number of funds for the development of novel antibiotics have led research efforts toward the study of specific cost-effective strategies aimed at discovering drugs against microbial infections. Among the potential options, drug repositioning, which has already exhibited satisfactory results in other medical fields, came out as the most promising. It consists of finding new uses for previously approved medicines and, over the years, many “repurposed drugs” displayed some encouraging in vitro and in vivo results beyond their initial application. The principal theoretical justification for reusing already existing drugs is that they have known mechanisms of action and manageable side effects. Reuse of old drugs is now considered an interesting approach to overcome the drawbacks of conventional antibiotics. The purpose of this review is to offer the reader a panoramic view of the updated studies concerning the repositioning process of different classes of non-antibiotic drugs in the antimicrobial field. Several research works reported the ability of some non-steroidal anti-inflammatory drugs (NSAIDs), antidepressants, antipsychotics, and statins to counteract the growth of harmful microorganisms, demonstrating an interesting winning mode to fight infectious diseases caused by antimicrobial resistant bacteria.

Drug repurposing to overcome microbial resistance

Infections are a growing global threat, and the number of resistant species of microbial pathogens is alarming. However, the rapid development of cross-resistant or multidrug-resistant strains and the development of so-called 'superbugs' are in stark contrast to the number of newly launched anti-infectives on the market. In this review, I summarize the causes of antimicrobial resistance, briefly discuss different approaches to the discovery and development of new anti-infective drugs, and focus on drug repurposing strategy, which is discussed from all possible perspectives. A comprehensive overview of drugs of other indications tested for their in vitro antimicrobial activity to support existing anti-infective therapeutics is provided, including several critical remarks on this strategy of repurposing non-antibiotics to antibacterial drugs.

Anti-infective properties of proton pump inhibitors: perspectives

Infectious diseases are among the main causes of morbidity and mortality today. In facing this crisis, the development of new drug options and combat strategies is necessary. In this sense, drug repositioning or drug redirection has emerged for the faster identification of effective drugs. In this “Commentary,” the anti-infective properties of the class of proton pump inhibitors (PPIs) are emphasized. Studies report activities against bacterial, fungal, parasitic, and viral agents. In addition, we have provided in a table a summary of the specific characteristics of PPIs and some of their anti-infective activities.

Repositioning of non-antibiotic drugs as an alternative to microbial resistance: a systematic review

The global spread of microbial resistance coupled with high costs and slow pace in the discovery of a new antibiotic have made drug repositioning an attractive and promising alternative in the treatment of infections caused by multidrug resistant (MDR) microorganisms. The reuse involves the production of compounds with lower costs and development time, using diversified production technologies. The present systematic review aimed to present a selection of studies published in the last 20 years, which report the antimicrobial activity of non-antibiotic drugs that are candidates for repositioning, which could be used against the current microbial multidrug resistance. A search was performed in the PubMed, SciELO and Google Scholar databases using the following search strategies: [(drug repurposing) OR (drug repositioning) OR (repositioning) AND (non-antibiotic) AND (antibacterial activity) AND (antimicrobial activity)]. Overall, 112 articles were included, which explored the antimicrobial activity in antidepressants, antihypertensives, anti-inflammatories, antineoplastics, hypoglycemic agents, among other drugs. It was concluded that they have significant antimicrobial activity in vitro and in vivo, against standard strain and clinical isolates (Gram-negative and Gram-positive) and fungi. When associated with antibacterials, most of these drugs had their antibacterial activity enhanced. It was also a consensus of the studies included in this review that the presence of aromatic rings in the molecular structure contributes to antimicrobial activity. This review highlights the potential repositioning of several classes of non-antibiotic drugs as promising candidates for repositioning in the treatment of severe bacterial infections of MDR bacteria, extensively resistant (XDR) and pan-resistant (PDR) to drugs.

Repurposing of escitalopram oxalate and clonazepam in combination with ciprofloxacin and sulfamethoxazole-trimethoprim for treatment of multidrug-resistant microorganisms and evaluation of the cleavage capacity of plasmid DNA

Bacterial resistance has become one of the most serious public health problems, globally, and drug repurposing is being investigated to speed up the identification of effective drugs. The aim of this study was to investigate the repurposing of escitalopram oxalate and clonazepam drugs individually, and in combination with the antibiotics ciprofloxacin and sulfamethoxazole-trimethoprim, to treat multidrug-resistant (MDR) microorganisms and to evaluate the potential chemical nuclease activity. The minimum inhibitory concentration, minimum bactericidal concentration, fractional inhibitory concentration index, and tolerance level were determined for each microorganism tested. In vitro antibacterial activity was evaluated against 47 multidrug-resistant clinical isolates and 11 standard bacterial strains from the American Type Culture Collection. Escitalopram oxalate was mainly active against Gram-positive bacteria, and clonazepam was active against both Gram-positive and Gram-negative bacteria. When associated with the two antibiotics mentioned, they had a significant synergistic effect. Clonazepam cleaved plasmid DNA, and the mechanisms involved were oxidative and hydrolytic. These results indicate the potential for repurposing these non-antibiotic drugs to treat bacterial infections. However, further studies on the mechanism of action of these drugs should be performed to ensure their safe use.