Globally Distributed Drug Discovery of New Antibiotics: Design and Combinatorial Synthesis of Amino Acid Derivatives in the Organic Chemistry Laboratory

An experiment for the synthesis of N-acyl derivatives of natural amino acids has been developed as part of the Distributed Drug Discovery (D3) program. Students use solid-phase synthesis techniques to complete a three-step, combinatorial synthesis of six products, which are analyzed using LC–MS and NMR spectroscopy. This protocol is suitable for introductory organic laboratory students and has been successfully implemented at multiple academic sites internationally. Accompanying prelab activities introduce students to SciFinder and to medicinal chemistry design principles. Pairing of these activities with the laboratory work provides students an authentic and cohesive research project experience

The Synthesis and Biological Activity of N-Acylated Amino Acids. A Collaborative Effort of Distributed Drug Discovery (D3)

poster abstractAs part of a Distributed Drug Discovery collaborative effort between students at IUPUI and Medical University of Lublin (Poland), the solid-phase combinatorial synthesis of a series of natural, acylated tyrosine (1) and phenylalanine (2) analogs was carried out in replicated fashion. The crude samples were purified and characterized by LC/MS, proton NMR, and in cases involving novel structures, by proton and carbon-13 NMR and high-resolution mass spectrometry. The samples were characterized in biological assays at the Medical University of Lublin against the Gram-positive bacteria Staphylococcus aureus ATCC 25923, Staphylococcus epidermidis ATCC 12228, Bacillus cereus ATCC 10876, Bacillus subtilis ATCC 10876, and Micrococcus luteus ATCC 10240. Although activity of the 2-nitro and 3-nitro derivatives of phenylalanine was not reproduced by the IUPUI samples, the 5-chlorosalicylic acid derivative 1g demonstrated good activity against M. luteus (MIC = 62.5 g/mL) and moderate activity against S. aureus, S. epidermidis, and B. cereus. O Cl OH HN OH OH O O Ar HN X OH O 1 X = OH 2 X = H 1

Synergistic Interactions between Linalool and Some Antimycotic Agents against <i>Candida</i> spp. as a Basis for Developing New Antifungal Preparations

The incidence of superficial infections, including oral candidiasis, has recently increased significantly. Their treatment is quite difficult due to the growing resistance of Candida spp. to antifungal agents. Therefore, it is necessary to search for novel antimycotics or alternative antifungal therapies. The purpose of the study was to evaluate the antifungal activity of natural terpene—linalool (LIN)—against both reference fungi belonging to yeasts and Candida spp. isolates from the oral cavities of immunocompromised, hemato-oncology patients. Moreover, its mechanism of action and interactions with selected antifungal drugs or antiseptics were investigated. The broth microdilution technique, ergosterol or sorbitol tests, and a checkerboard method were used for individual studies. The LIN showed potential activity toward studied strains of fungi with a minimal inhibitory concentration (MIC) in the range of 0.5–8 mg/mL and fungicidal effect. This compound was also found to bind to ergosterol in the yeast cell membrane. Additionally, the interactions between LIN with antiseptics such as chlorhexidine, cetylpyridinium, and triclosan showed beneficial synergistic effect (with FIC = 0.3125–0.375), or an additive effect with silver nitrate and chlorquinaldol (FIC = 0.625–1). Moreover, statistically significant differences in MIC values were found for the synergistic combinations of LIN. No interaction was indicated for nystatin. These results confirm that the LIN seems to be a promising plant component used alone or in combination with other antimycotics in the prevention and treatment of superficial fungal infections. However, further clinical trials are required

Częstość występowania oraz zróżnicowanie gatunkowe grzybów z rodzaju Candida w górnych drogach oddechowych u osób w podeszłym wieku

Background. Respiratory tract infections, including candidiases, are important medical problem in elderly people. Such infections are usually of endogenous origin and are preceded by colonization of upper respiratory tract by Candida spp. The aim of the present paper was to evaluate the prevalence (colonization and carriage) of Candida spp. in mucous membranes of throat and/or nose in elderly people staying in care center and people living with families, in certain seasons of the year. Material and methods. Candida spp. were isolated from nasal and throat swabs collected from 110 elderly (> 65 years) people and identified with a use of conventional diagnostic methods. Results. Obtained results indicate that the prevalence rate of Candida spp. in elderly people in certain seasons was about 30-50%; during the overall period of the study, the rate of Candida spp. colonization was about 70% while carriage rate - about 50%. The predominant species was C. albicans (about 70%). Among non-albicans Candida spp., the most frequently identified species were C. glabrata, C. tropicalis and C. kefyr. Conclusions. Analysis of natural microflora of upper respiratory tract may provide valuable informations concerning actual qualitative and quantitative changes within Candida spp., reflecting with large probability changes in candidiases etiology.Wstęp. Zakażenia układu oddechowego stanowią ważny problem medyczny u osób w wieku podeszłym. Wśród postaci klinicznych tych zakażeń występują kandydozy górnych dróg oddechowych, które mają zazwyczaj charakter endogenny i są poprzedzone kolonizacją błon śluzowych gardła i/lub nosa przez grzyby z rodzaju Candida. Celem pracy była ocena dynamiki występowania (kolonizacji i nosicielstwa) Candida spp. w obrębie błon śluzowych górnych dróg oddechowych u osób starszych z domu opieki społecznej oraz osób spoza zakładu opiekuńczego w poszczególnych porach roku. Materiał i metody. Izolacji grzybów z rodzaju Candida z wymazów z gardła i nosa u 110 osób starszych (> 65. rż.) oraz ich identyfikacji dokonano za pomocą klasycznych metod diagnostycznych. Wyniki. Częstość występowania grzybów z rodzaju Candida w obrębie błon śluzowych górnych dróg oddechowych u osób w wieku podeszłym w poszczególnych badaniach wynosiła około 30-50%. Uwzględniając natomiast całoroczny cykl badań, wykazano wysoki odsetek kolonizacji (ok. 70%) oraz nosicielstwa (ok. 50%) drożdżaków. Stwierdzono, że zasiedlały one głównie śluzówkę gardła, zaś dominującym gatunkiem, stanowiącym około 70% wszystkich wyizolowanych szczepów, był C. albicans. Spośród drożdżaków innych niż C. albicans (nie-albicans Candida spp.) zidentyfikowano najwięcej C. glabrata, C. tropicalis oraz C. kefyr. Wnioski. Analiza naturalnej mikroflory grzybiczej ontocenozy górnych dróg oddechowych u osób w wieku podeszłym może dostarczyć cennych informacji dotyczących aktualnych tendencji w zmianach składu jakościowego i ilościowego w obrębie Candida spp. w tej grupie wiekowej, co z kolei może wpływać na ich udział w etiologii kandydoz

Synthesis and investigation of antimicrobial activities of nitrofurazone analogues containing hydrazide-hydrazone moiety

In this research we synthesized and tested for in vitro antimicrobial activity 21 nitrofurazone analogues. The compounds we obtained were identified on the basis of 1H NMR and 13C NMR spectroscopy. The in vitro screening of antimicrobial properties of synthesized compounds revealed a wide spectrum of antimicrobial activity. Compounds 28, 29, 32–43, and 45–48 showed very high bactericidal effect towards Staphylococcus spp. ATTC and Bacillus spp. ATTC (MIC = 0.002–7.81 µg/ml and MBC = 0.002–31.25 µg/ml). The levels of activity of several compounds were far better than those of nitrofurantoin, ciprofloxacin or cefuroxime

Fosfomycin activity in vitro against Escherichia coli strains isolated from urine specimens

Urinary tract infections are caused mostly by uropathogenic Escherichia coli strains. The aim of this paper was to assess the activity of fosfomycin in vitro against 74 E. coli strains isolated from urine samples of outpatients with acute cystitis. Minimum inhibitory concentration (MIC) was determined by the recommended method of serial drug dilution in Mueller-Hinton agar supplemented with glucose-6-phosphate (25 mg/L). The estimated MIC values were in the range of 1-32 mg/L. The prevalence of fosfomycin-sensitive strains was 45.9%, while that of fosfomycin-resistant strains – 54.1%. The time-kill assay was performed for a chosen clinical strain (MIC = 1 mg/L) in Mueller-Hinton broth also supplemented with glucose-6-phosphate in the presence of various concentrations of fosfomycin (0.5-64 mg/L). The bacterial population density was expressed as log CFU (colony forming units)/mL. The decrease of the bacterial population viability after 6h incubation was found with ∆log CFU/mL = 1.05-5.02, depending on fosfomycin concentration. However, bactericidal effect of this antibiotic (∆log CFU/mL >3) was observed only at the highest concentrations (32-64 mg/L). Moreover, after prolonged incubation (24 h), the re-growth of bacterial population revealed as the increase of its viability (∆log CFU/mL = 1.03-3.03) was observed at fosfomycin concentration in the range 0.5-32 mg/L, but not at 64 mg/L. This phenomenon may be due the presence of subpopulations of spontaneous mutants sensitive only to higher concentrations of this antibiotic comparing to MIC. The presented data confirm a need to monitor the sensitivity of uropathogenic E. coli strains to fosfomycin

Comparison of microdilution method and E-test procedure in susceptibility testing of caspofungin against Candida non-albicans species. New Microbiol

It is widely known that systemic and mucosal candidiasis caused by Candida non-albicans strains endangers the lives of hospitalised patients since these pathogens are extremely difficult to defeat by commonly used antifungal agents. The present study determined the in vitro activities of a novel antimicotic drug -caspofungin -against 76 Candida nonalbicans isolates by means of the CLSI reference method for broth dilution antifungal susceptibility testing of yeasts and the E-test procedure for comparison. Caspofungin was efficacious against the majority of strains tested, with the average MICs 90 evaluated by the microdilution method and E-tests amounting to 1 mg/l and 0.5 mg/l, respectively. Since the agreement between MICs within ±2 dilutions obtained by these two techniques was 92% (Kappa coefficient of 0.92), the E-test procedure seems to be a reliable alternative to the broth microdilution method and may provide another choice for clinical laboratories