Thyroid diseases affect a considerable portion of the population being hypothyroidism one of the most commonly reported¹. Levothyroxine (T4) is used clinically to treat hypothyroidism, however, the narrow therapeutic index of this drug, the need for a frequent administration and the influence of gastrointestinal diseases, foods and other drugs on its absorption are the shortcomings related with oral administration of T4.²

There are several approaches to enhance the drug solubility and bioavailability such as particle size reduction, nanosuspension, use of surfactants, salt formation, solid dispersion, among others³. In this work, an attempt to improve T4 solubility through the synthesis of T4 salts based on Organic Salts and Ionic Liquids (OSILs) and on its dispersion into biocompatible aerogels matrixes, is made. OSILs based on pharmaceutical drugs (API-OSILs) is a class of salts with promissory therapeutic properties.⁴ Herein, T4 was used as anion in combination with choline and 1-ethanol-3-methylimidazolium [C2OHMIM] cations. All compounds were characterized by 1H- and 13C-NMR, FTIR and elemental analysis in order to confirm their structures and purity levels. Aerogels are a special class of nanoporous materials with growing application in the biomedical and pharmaceutical fields due to their open pore structure and high surface area capable of active adsorption and releasing desired compounds.⁵ The use of polysaccharides for the synthesis of aerogel matrices has additional benefits such as biodegradability and biocompatibility, which make them, promising as encapsulation and delivery systems of drug.⁵ In this work, composite aerogels based on locust bean gum and k-carrageenan were used as T4 carriers and delivery studies performed allowing for the determination of the drug solubility.

The water and serum solubility of the prepared T4-OSILs as well as the thermal analysis through differential scanning calorimetry (DSC) studies, have been carried out and also compared with original T4 drug. The poor water-soluble pharmaceutical drug T4 was loaded into the aerogel matrixes and the composites were characterized by attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) and by DSC; the results were compared with the original T4 drug. Release experiments were performed at physiologic pH using a phosphate buffer solution at pH 7.2.

Multiresistance in P. aeruginosa has greatly increased due to the presence of carbapenemases genes such as bla_KPC, discovered in Klebsiella pneumoniae and mobilized by horizontal transfer to other species and genera. Its dissemination has been mainly due to the Tn4401. However, some non-Tn4401 elements (NTE_KPC) associated with bla_KPC have been recently found in K. pneumoniae and other bacteria. The aim of this work was to characterize in silico the transposable elements associated with bla_KPC in P. aeruginosa according to the reports presented in GenBank, to contribute with information that allows elucidating the dissemination mechanisms of this resistance determinant. To identify these elements, a search algorithm was performed using NCBI databases, sequences were filtered, and paired alignments with ACT and EasyFig were performed to characterize the bla_KPC upstream region and to determine the carrier sequences such as Tn4401 or NTE_KPC. When Tn4401 presence was discarded, the genetic environment of bla_KPC was characterized by using specialized databases such as ISFinder, CARD, among others. Using specific regions of the NTE_KPC variants, PCR oligonucleotides were designed targeting these elements and assessed in a cohort of 61 clinical isolates, recovered in 5 Colombian institutions. As a result of the in-silico approach we found 55 bla_KPC positive isolates (after being filtered) of which 73 % were carried in an NTE_KPC. All of them were associated with the bla_KPC-2 variant. These results show NTE_KPC are the most frequently reported environments in this species in the GenBank. On the PCR assay, the results showed that, even though Tn4401 was the most frequent element in Colombia, NTE_KPC-IIf was presented in a significant number of isolates (29.5%) and circulates in different genetic lineages. Interestingly, the NTE_KPC-IIf has not been reported in any other organism. This study contributes to the knowledge of carbapenems resistance dissemination mechanisms in P. aeruginosa.

Pseudomonas aeruginosa is one of the most commonly isolated opportunistic pathogens and is globally recognized as a serious threat because of its immunity to nearly all known antibiotics. The genome of this human pathogen, causing life-threatening infections, contains three genes, PAO102, PA2053, and PA4676, encoding for putative beta-carbonic anhydrases (b-CAs) psCA1, psCA2, and psCA3, respectively. b-CAs are zinc metalloenzymes that catalyze reversible CO₂ hydration to bicarbonate. By performing their function b-CAs maintain the intracellular balance of CO₂ and bicarbonate inside the cell. This chemical equilibrium is needed for most of the intercellular biosynthetic reactions and is vitally important for the survival of the pathogen. Therefore, the importance of the b-CAs in bacterial physiology makes these metalloenzymes a promising group of antimicrobial drug targets. In this study b-CAs of P. aeruginosa were cloned, heterologously expressed, and purified. The protein stability and catalytic activity analysis has confirmed that the recombinantly expressed his-tagged P. aeruginosa b-CAs demonstrate identical properties and catalytic activity to native b-CAs, therefore they can be used for potential inhibitor screening. A library of commercially available CA inhibitors was tested using recombinant proteins to determine the ability of these ligands to bind b-CAs of P. aeruginosa. None of the investigated molecules were able to bind psCA1, nevertheless, 2 of them were able to bind psCA2, and 4 were able to bind psCA3. The dissociation constants of ligands that can bind b-CAs were found to vary mostly in the micromolar range under different binding conditions, therefore these molecules appear to be promising inhibitors of b-CAs psCA2 and psCA3.

Urinary tract infections (UTIs) are one of the most common bacterial infections in adults. The prevalent problem and emergence of methicillin-resistant Staphylococcus aureus (MRSA) among adult urinary tract pathogens has been recently reported. Thus, this study is undertaken to identify the MRSA along with their antimicrobial susceptibility pattern as well to detect mecA genes among out-patients adults diagnosed with UTIs in Zakho city, Kurdistan-Iraq. A total of 27 Staphylococcus aureus isolates were recovered from 330 urine samples with UTIs aged (18-60 years) and collected from Zakho General Teaching Hospital in Zakho City, between August 2021 and the end of February 2022. Antimicrobial sensitivity patterns were determined by the Kirby Bauer disc diffusion method as well all of these isolates were screened for the presence of nuc and mecA genes using polymerase chain reaction. The proportions of infected females (81%) were significantly higher than male and all these isolates were confirmed to presence both nuc and meca genes. Roughly all S.aureus were resistant to both cefixime and ampicillin and additionally, around ¾ of them were resistant to erythromycin, trimethoprim, methicillin, vancomycin, oxacillin, cloxacillin and cefotaxime. This study shows the prevalence of MRSA isolates from adult patients with suspected UTIs and imipenem was the most effective antibiotic (about 90%) against these S. aureus.

Introduction: Acinetobacter baumannii is an aerobic Gram-negative bacterium which causes facultative hospital infections and in settings like Greece exhibits high resistance rates against most antimicrobial agents. Cefiderocol is a siderophore cephalosporin intended to treat infections due to multi-drug resistant (MDR) Gram negative aerobic bacteria. The aim of our study was to assess the in vitro activity of cefiderocol and comparators against multidrug resistant Acinetobacter baumannii isolates.

Methods: A total of 29 MDR Acinetobacter baumannii strains recovered from clinical samples (23 blood, 2 central line catheters, 2 bronchial aspirates, 1 pus and 1 urine) from January to April 2022 were included in the study. Species identification and antimicrobial susceptibility testing for most comparators were performed with the Vitek®2 automated system (bioMérieux, France) except for colistin tested by the broth microdilution method using the ComASP™ Colistin 0.25-16 μg/mL panel (Liofilchem®) and tigecyclin tested by Liofilchem® MIC Test Strips. Cefiderocol MICs were determined via the Liofilchem® MIC Test Strips on Mueller Hinton II Agar (BD™). MIC₅₀ and MIC₉₀ were calculated for all antimicrobials and EUCAST 2022 clinical breakpoints were applied wherever applicable. Susceptibility to tigecyclin was interpreted according to the FDA breakpoints and to cefiderocol according to the EUCAST PK/PD breakpoints. Pseudomonas aeruginosa ATCC25853 and Klebsiella pneumoniae ATCC700603 were used as quality control.

Results: Cefiderocol MICs ranged from 0.064 to >256 mg/L with the majority of the isolates being susceptible. The comparators had very low to zero susceptibility rates against the tested isolates. MIC₅₀, MIC₉₀, MIC range and susceptibility rates are displayed analytically on Table 1.

Discussion: Cefiderocol exhibited potent in vitro activity against MDR Acinetobacter baumannii isolates. It seems to be a valuable option where limited or no therapeutic alternatives are available.

Persister cells (PC) are non-growing and metabolically inactive cells, which lack transcription, translation, and proton motive force. PC formation was reported to occur by (ⅰ) stochastically (ⅱ) antibiotic treatment (ⅲ) nutrient deprivation and (ⅳ) other biofilm-related condition. PCs are responsible for chronic and relapse of biofilm infections as well as bacterial infections. Pseudomonas aeruginosa (Pa) is an opportunistic pathogen frequently causing chronic airway infections in patients with cystic fibrosis (CF), chronic urinary tract infection (UTI), and ventilator-associated pneumonia. For this study, Pa isolates; TP-10, ST-13, and POA1 were used. The Minimum Inhibitory Concentration (MIC) was determined and time-kill assay was carried out for PC isolation in the planktonic stage. Further, Flow Cytometry (FC) and qRT-PCR for stringent response genes (rel A, spo T and lon) and toxin-antitoxin (hig B and hig A) were done. A biphasic kill curve pattern was observed which varied across the antibiotic treatment. Starting from 12-13 log₁₀ cfu/ml mean inoculum, after ceftazidime treatment 9-10 log₁₀ cfu/ml lasted, while on gentamicin and ciprofloxacin treatment 5-6 log₁₀ cfu/ml lasted and formed biphasic pattern. The PC were analyzed through FC using Redox sensor green (RSG) and propidium iodide (PI) staining. It was observed that ceftazidime treatment has high redox activities followed by ciprofloxacin and gentamicin treatment compared to untreated isolate. Whereas ST-13 isolate had high redox activities on ceftazidime treatment followed by gentamicin and ciprofloxacin. The rel A, spo T, lon, hig B and hig A genes were upregulated on ceftazidime and gentamicin treatment compared to untreated in PAO1 and TP-10 isolates. Whereas in ST-13 isolate, genes were upregulated on gentamicin treatment. From the above study, it can be concluded that gentamicin and ceftazidime lead to PCs formation in P. aeruginosa planktonic stage.

Background: The excellent features of non-invasive molecular imaging, its progressive technology (real-time, whole-body imaging and quantification), and global impact by a growing infrastructure for positron emission tomography (PET) scanners are encouraging prospects to investigate new concepts which could transform clinical care of complex infectious diseases. Researchers are aiming towards the extension beyond the routinely available radiopharmaceuticals looking for more effective tools that interact directly with causative pathogens. We were interested to investigate whether the actual use of antibiotics as PET-radiotracers can be successful or might be too much of a challenge.

Methods: We systematically reviewed and critically evaluated antibiotic-derived PET radiopharmaceutical development efforts aimed at infection imaging either considered for a) radiotracer development for infection imaging or b) radio-antibiotic based PET imaging supplementing other tools for pharmacologic drug characterization. Overall, a total of twenty original PET radiotracers derived from eleven different approved antibiotics (*listed below). A critical, in-depth assessment was performed thereby revealing the challenges and pitfalls reflecting on antibiotics as input for their radiopharmaceutical development as infection imaging agents.

Results: There are a few shortcomings making the antibiotic scaffold for radiotracer development a questionable choice: a) the radiolabelling protocol is unable to match with antibiotic activity, b) a risk of compromised tracer sensitivity, c) the risk of questionable accuracy of visualizing infectious foci in humans, d) the detrimental effect of the rampant (often only prophylactical) use of antibiotics mismatching radiotracers of antibiotic origin, and e) the occurrence of misjudged radiotracer bioavailability and unwanted biodistribution. Our conceivable strategies or solutions to overcome these pitfalls may therefore include: the more efficient, early-on usage of computational tests, data libraries or structure-activity-relationship (SAR) investigations, a proactive disregard for antibiotics with a cumbersome or predisposed mechanism of action (e.g., selection of molecules showing unique mechanisms of action), pre-emptive action towards the different isotopic mass effect for radiotracer preparation, opting for radiotracer testing in non-human primates to supplement phase-0 clinical trial safety dossiers, selecting vectors (for drug-resistant pathogens) that support target overexpression or genetic redundancy. Particularly burdensome radiotracer ADME effects may be conquered by the following guidelines: prioritize antibiotics featuring a rapid clearance from high-risk organs for infection, perform candidate selection based on host-enzymatic and tissue-specific interactions, practice SAR-guided incorporation of a radiolabelled functional group, contemplate pharmacologically inert delivery systems, and solely permit radionuclide incorporation into non-cleavable prosthetic groups.

Conclusion: We found that antibiotic-derived PET-radiotracer development is very scattered and often represented by single studies, afflicted with incoherent study designs which consequently introduce biases which, in turn, reduces the validity and reliability of otherwise promising results. However, the high-quality and extensive studies on carbon-11– and fluoride-18-labelled trimethoprim has sparked new belief that antibiotics can become clinically relevant infection imaging agents that facilitate improving disease prognostication and allow for more intricate understanding the mechanisms governing antibiotic performance and emergence of resistance.

*List of PET radiotracers

1) [¹¹C]trimethoprim

2) [¹⁸F]FP-trimethoprim

3) [¹⁸F]F-ciprofloxacin

4) [⁶⁸Ga]Ga(NOTA-SCN)-ciprofloxacin

5) [⁶⁸Ga]Ga(DOTA-SCN)-ciprofloxacin

6) [⁶⁸Ga]Ga-DOTA-ciprofloxacin

7) [¹⁸F]FP-ciprofloxacin

8) [¹⁸F]F-lomefloxacin

9) [¹⁸F]F-fleroxacin

10) [¹⁸F]F-trovafloxacin

11) [¹¹C]isoniazid

12) 2-[¹⁸F]F-isoniazid

13) [¹¹C]PT70 (Isoniazid analogue)

14) [¹¹C]PT119 (Isoniazid analogue)

15) [¹¹C]pyrazinamide

16) 5-[¹⁸F]F-pyrazinamide

17) [¹⁸F]F-linezolid

18) [⁷⁶Br]Br-bedaquiline

19) [¹¹C]rifampin

20) [¹¹C]erythromycin

Resistance of bacteria and fungi to antibiotics and other drugs is recognized as one of the major problems in current medicine. Therefore, a search for new biologically active compounds able to either kill pathogenic cells or inhibit their growth is mandatory. Hard-to-reach habitats appear to be unexplored sources of microorganisms producing previously unknown antibiotics and other molecules revealing potentially therapeutic properties. Caves belong to such habitats, and Actinobacteria are a predominant group of microorganisms occurring there. This group of bacteria are known for production of many antibiotics and other bioactive compounds. Here, a series of newly isolated strains of Actinobacteria that were found in caves from the Tatra Mountains (Poland) will be presented. Among all the examined bacteria, two newly isolated Streptomyces sp. strains were further characterized to demonstrate their ability to inhibit the growth of pathogenic bacteria (strains of Staphylococcus aureus, Salmonella enterica, Enterococcus sp., Escherichia coli, and Pseudomonas aeruginosa) and fungi (different species and strains from the genus Candida). Chemical analyses of these extracts indicated the presence of isomers of dichloranthrabenzoxocinone and 4,10- or 10,12-dichloro-3-O-methylanthrabenzoxocinone, which are putative antimicrobial compounds. Moreover, various previously unknown (unclassified) molecules were also detected using liquid chromatography-mass spectrometry, suggesting that tested Streptomyces strains may synthesize a battery of bioactive compounds with antibacterial and antifungal activities. These results indicate that further studies on the newly isolated Actinobacteria might be a promising approach to develop novel antimicrobial drugs.

A drug is defined as a substance capable of influencing biological functions through chemical reactions, either by agonism or antagonism, to achieve the desired therapeutic effect. During this process, several pharmacokinetic and pharmacodynamic events occur, which can be potential sites for drug interactions to occur. For patients undergoing hospital treatment, drugs of different classes are usually prescribed, and it is necessary to understand the risk of interactions between these drugs and their possible change in therapeutic efficacy or safety. Therefore, the study sought to identify the main classes of drugs, and their combinations, used in the treatment of pneumonia in pediatric patients at a teaching hospital in Brazil. This is a cross-sectional, retrospective and descriptive study, from September 2017 to December 2020, based on data obtained from medical records provided by the Júlio Bandeira University Hospital. Regarding the most used antibiotics in the analyzed period, we have: ampicillin (61.76%) and azithromycin (23.53%) in 2017; ampicillin (41.04%) and ceftriaxone (23.51%) in 2018; ampicillin (45.70%) and ceftriaxone (25.50%) in 2019; ceftriaxone (39.20%) and azithromycin (31.49%) in 2020. The main combinations identified in the study were: dipyrone and fenoterol (60.70%), dipyrone and hydrocortisone (47.92%), dipyrone and ondansetron (34.66%) and dipyrone, hydrocortisone and fenoterol (37.38%). It is important to highlight that 58 different drugs were found in the prescriptions of this period, alerting to the possibility of drug interactions of various types. In view of this, it is possible to highlight the combination of azithromycin and ondansetron as a potentially moderate risk of drug interaction, since both increase the QT interval, requiring patient monitoring by means of ECG. Therefore, an in-depth analysis of these data may be useful to prepare technical material and assist in therapeutic decision-making, improving the quality of prescriptions and the patient's clinical response, adopting an even more effective conduct, with adequate care and as close to the patient as possible. expected in relation to the pharmacological characteristics of drugs.

Antibiotic research efforts for the identification of effective antibiotics can be accelerated through computational screening tools that can accurately identify novel, antimicrobial compounds. This study employed machine learning algorithms to identify lead compounds that inhibit the antibiotic targets, DNA gyrase and Dihydrofolate reductase in Escherichia coli, and identified new, multifaceted antimicrobial compounds. This study used three separate datasets: 1) 326 Escherichia coli DNA gyrase inhibitors and 132 non-inhibitors, 2) 346 Escherichia coli Dihydrofolate reductase inhibitors and 176 non-inhibitors, and 3) 18387 non-specific drug-like chemicals. All datasets were then processed using ECFP-4 fingerprints and split into train, test, and validation datasets according to a 70-15-15 train-test-validation split. We explored the potential of 6 different classification algorithms, all optimized with Bayesian Optimization. Performance was evaluated using accuracy, precision, recall, F1-score, and AUC. Our results indicate that the Gradient Boosting Classifier (GBC) performed the best at identifying a compound's efficacy towards DNA gyrase with an accuracy, precision, recall, F1-score, and AUC of 91%, 92%, 86%, 88%, and 0.933, respectively. The Random Forest Classifier (RFC) performed optimally for identifying a compound’s effectiveness towards Dihydrofolate reductase with an accuracy, precision, recall, F1-score, and AUC of 86%, 83%, 85%, 84%, and 0.944, respectively. As a result, the GBC and RFC were used to search for compounds that inhibited both DNA gyrase and Dihydrofolate reductase. Out of 18387 compounds, we identified 5 novel compounds that have a predicted probability greater than 95% to inhibit both DNA gyrase and Dihydrofolate reductase, suggesting a high antimicrobial potential. Using the GBC and RFC models, we also generated similarity maps, uncovering potential pharmacophores for DNA gyrase and Dihydrofolate reductase. The models evaluated in this study, particularly the GBC and RFC models, hold tremendous promise in computationally screening large libraries of compounds for antimicrobial potential.