Antimicrobial resistance (AMR) has emerged as a major threat to public health globally. Accurate and rapid detection of resistance to antimicrobial drugs, and subsequent appropriate antimicrobial treatment, combined with antimicrobial stewardship, are essential for controlling the emergence and spread of AMR. This article reviews common antimicrobial susceptibility testing (AST) methods and relevant issues concerning the advantages and disadvantages of each method. Although accurate, classic technologies used in clinical microbiology to profile antimicrobial susceptibility are time-consuming and relatively expensive. As a result, physicians often prescribe empirical antimicrobial therapies and broad-spectrum antibiotics. Although recently developed AST systems have shown advantages over traditional methods in terms of testing speed and the potential for providing a deeper insight into resistance mechanisms, extensive validation is required to translate these methodologies to clinical practice. With a continuous increase in antimicrobial resistance, additional efforts are needed to develop innovative, rapid, accurate, and portable diagnostic tools for AST. The wide implementation of novel devices would enable the identification of the optimal treatment approaches and the surveillance of antibiotic resistance in health, agriculture, and the environment, allowing monitoring and better tackling the emergence of AMR.

Background/Objectives: Antimicrobial resistance poses a major public health challenge. The World Health Organization has identified 15 priority pathogens that require prompt development of new antibiotics. This review systematically evaluates the antibacterial resistance of the most significant bacterial pathogens, currently available treatment options, as well as complementary approaches for the management of infections caused by the most challenging multidrug-resistant (MDR) bacteria. For carbapenem-resistant Gram-negative bacteria, treatment options include combinations of beta-lactam antibiotics and beta-lactamase inhibitors, a novel siderophore cephalosporin, known as cefiderocol, as well as older antibiotics like polymixins and tigecycline. Treatment options for Gram-positive bacteria are vancomycin, daptomycin, linezolid, etc. Although the development of new antibiotics has stagnated, various agents with antibacterial properties are currently in clinical and preclinical trials. Non-antibiotic strategies encompass antibiotic potentiators, bacteriophage therapy, antivirulence therapeutics, antimicrobial peptides, antibacterial nanomaterials, host-directed therapy, vaccines, antibodies, plant-based products, repurposed drugs, as well as their combinations, including those used alongside antibiotics. Significant challenges exist in developing new antimicrobials, particularly related to scientific and technical issues, along with policy and economic factors. Currently, most of the alternative options are not part of routine treatment protocols. Conclusions and Future Directions: There is an urgent need to expedite the development of new strategies for treating infections caused by MDR bacteria. This requires a multidisciplinary approach that involves collaboration across research, healthcare, and regulatory bodies. Suggested approaches are crucial for addressing this challenge and should be backed by rational antibiotic use, enhanced infection control practices, and improved surveillance systems for emerging pathogens.

Gentamicin, belonging to the aminoglycosides, possesses the greatest nephrotoxic effect of all other antibiotics from this group. On the other hand, pioglitazone, which represents peroxisome proliferator-activated receptor γ (PPARγ) agonist recently showed antiinflamatory, antioxidative effects, amelioration of endothelial dysfunction etc. Therefore, the goal of our study was to investigate the effects of pioglitazone on kidney injury in an experimental model of gentamicin-induced nephrotoxicity in rats. These effects were observed by following values of biochemical (serum urea and creatinine) parametars, total histological kidney score, urine level of kidney injury molecule-1 (KIM-1) and neutrophil gelatinase-associated lipocalin (NGAL) as well as parametars of oxidative stress (malondialdehyde, superoxide dismutase, catalase, total oxidant status, total antioxidant status, oxidative stress index and advanced oxidation protein products). It seems that pioglitazone protects the injured rat kidney in a U-shaped manner. Medium dose of pioglitazone (1 mg/kg, i.p.) was protective regarding biochemical (serum urea and creatinine), total histological score and the values of kidney injury molecule-1 (KIM-1) (P < 0.05 vs. control group, i.e. rats injected with gentamicin only). This finding could be of great importance for the wider use of aminoglycosides, with therapy that would reduce the occurrence of serious adverse effects, such as nephrotoxicity and acute renal failure.

Antimicrobial resistance (AMR) poses a substantial threat to human health. The commensal bacteria of the gut microbiome were shown to serve as a reservoir of antibiotic resistance genes (ARGs), termed the gut resistome, which has the potential to transfer horizontally to pathogens and contribute to the emergence of drug-resistant bacteria. Namely, AMR traits are generally linked with mobile genetic elements (MGEs), which apart from disseminating vertically to the progeny, may cross horizontally to the distantly related microbial species. On the other hand, while probiotics are generally considered beneficiary to human health, and are therefore widely consumed in recent years most commonly in conjunction with antibiotics, the complexities and extent of their impact on the gut microbiome and resistome have not been elucidated. By reviewing the latest studies on ARG containing commercial probiotic products and common probiotic supplement species with their actual effects on the human gut resistome, this study aims to demonstrate that their contribution to the spread of ARGs along the GI tract merits additional attention, but also indicates the changes in sampling and profiling of the gut microbiome which may allow for the more comprehensive studying of the effects of probiotics in this part of the resistome.

This study aimed to investigate the biofilm-production ability of carbapenem-resistant Acinetobacter baumannii (CRAB), the biofilm-eradication potential of 70% ethanol and 0.5% sodium hypochlorite, the effects of selenium nanoparticles (SeNPs) against planktonic and biofilm-embedded CRAB, and the relationship between biofilm production and bacterial genotypes. A total of 111 CRAB isolates were tested for antimicrobial susceptibility, biofilm formation, presence of the genes encoding carbapenemases, and biofilm-associated virulence factors. The antibiofilm effects of disinfectants and SeNPs against CRAB isolates were also tested. The vast majority of the tested isolates were biofilm producers (91.9%). The bap, ompA, and csuE genes were found in 57%, 70%, and 76% of the CRAB isolates, with the csuE being significantly more common among biofilm producers (78.6%) compared to non-biofilm-producing CRAB (25%). The tested disinfectants showed a better antibiofilm effect on moderate and strong biofilm producers than on weak producers (p < 0.01). The SeNPs showed an inhibitory effect against all tested planktonic (MIC range: 0.00015 to >1.25 mg/mL) and biofilm-embedded CRAB, with a minimum biofilm inhibitory concentration of less than 0.15 mg/mL for 90% of biofilm producers. In conclusion, SeNPs might be used as promising therapeutic and medical device coating agents, thus serving as an alternative approach for the prevention of biofilm-related infections.

This nationwide study aimed to investigate the molecular characteristics of metallo-β-lactamase (MBL)-producing Pseudomonas aeruginosa in Serbia, underlying resistance mechanisms, the genetic context of detected MBL genes, and the clonal relationship between isolates harboring genes-encoding MBL. Overall, 320/5334 isolates collected from 2018 to 2021 were identified as P. aeruginosa. Carbapenem-resistant P. aeruginosa (CRPA) were screened for the presence of bla_VIM, bla_IMP, and bla_NDM, genes whereas MBL-positive isolates were tested for the presence of the bla_CTX-M-2, bla_PER, bla_TEM, bla_SHV, bla_VEB, and bla_GES. Multilocus sequence typing and phylogenomic analysis were performed for P. aeruginosa-producing MBL. The majority of the P. aeruginosa isolates were recovered from the lower respiratory tract (n = 120; 37.5%) and wound specimens (n = 108; 33.75%). CRPA isolates accounted for 43.1% (n = 138) of the tested isolates, 31 out of them being bla_NDM-1-positive (22.5%). The colistin resistance rate was 0.3%. MLST analysis revealed the occurrence of ST235 (n = 25) and ST654 (n = 6), mostly confined to Serbia. The distribution of beta-lactamase-encoding genes in these isolates suggested clonal dissemination and possible recombination: ST235/bla_NDM-1, ST235/bla_NDM-1/bla_PER-1, ST654/bla_NDM-1, ST654/bla_NDM-1/bla_PER-1, and ST654/bla_NDM-1/bla_GES-5. High-risk clones ST235 and ST654 identified for the first time in Serbia, are important vectors of acquired MBL and ESBL and their associated multidrug resistance phenotypes represent a cause for considerable concern.