Agar-based Disk Diffusion Research Articles

Prevalence of Dermatophytic Infections and Their Antifungal Susceptibility Pattern in the Rajshahi Region

Background: Dermatophytes are the most significant fungi because of their widespread involvement in the population and their prevalence worldwide. Bangladesh's hot and humid climate, overcrowded population, poverty, malnutrition, and ignorance make dermatophytosis a common cutaneous infection. These infections occur in both healthy and immunocompromised patients. Dermatophytes are responsible for most cutaneous fungal infections, and the estimated lifetime risk of acquiring a dermatophyte infection is 10-20%.
 Objective: To isolate and identify different dermatophytes and their antifungal susceptibility pattern in the Rajshahi region. Materials and Methods: Different clinical samples (e.g., skin scrapings, nail clipping, and hair plucking) were collected under aseptic precautions. The isolation and identification of dermatophytes were performed through a microscopic examination using 10% KOH mount, mycological culture, and species identification by lactophenol cotton blue mount from positive culture. In addition, all dermatophytes isolates were subjected to antifungal susceptibility testing using the agar-based disk diffusion method in Mueller Hinton agar media.
 Results: Out of 171 samples, Trichophyton rubrum was the predominant dermatophyte species with 76(71.7%), followed by T.mentagrophyte were 15(14.2%), E. floccosum were 12(11.3%), and M. canis were 03(2.8%). voriconazole, clotrimazole, and itraconazole were more effective drugs. Griseofulvin was the least effective drug, followed by fluconazole.
 Conclusion: This study indicates dermatophytosis is a common skin disease in northern Bangladesh. Due to the increasing trend of antifungal drug resistance among dermatophytes, treatment should be based on antifungal sensitivity testing.
 TAJ 2022; 36: No-1: 119-125

A study of antifungal susceptibility pattern of dermatophytes at tertiary care center

Dermatophytes are fungi that can cause infections of the skin, hair & nails due to their ability to invade keratin. Dermatophytosis is the most common superficial fungal infection worldwide; it is common in tropics and subtropical regions. It may present in epidemic proportions in areas of high humidity: The present study aimed to identify various species causing dermatophytosis & to determine the invitro susceptibility pattern against commonly used systemic antifungal agents in our tertiary care center.A total of 149 samples were collected of infected skin, hair and nails in a period of 1 year from January 2020 to December 2020. Samples were collected under aseptic condition by skin scrapping, nail and hair clipping by using scalpel or forceps. Identification of the causative pathogen was done by performing slide culture, lacto-phenol cotton blue mount, hair perforation tests and urease tests. We adopted a newly developed agar based disk diffusion assay to test susceptibility of clinically isolated dermatophytes for antifungal susceptibility testing.Microbiological investigations revealed the presence of dermatophytic fungi in 71.8% of the samples. Trichophyton rubrum was the predominant pathogen isolated. The study showed Itraconazole to be most effective antifungal drugs against dermatophytes followed by terbinafine and fluconazole.Further intensive epidemiological and invitro antifungal susceptibility studies of dermatophytes are required which will have more public health significance.

Antifungal Susceptibility Testing of Dermatophytes by ABDD and E-Test, a Comparative Study

Aim: The objective of this study was to isolate, identify, and explore the in-vitro antifungal susceptibility pattern of dermatophytes isolated from clinically suspected cases of dermatophytosis (tinea infections) attending the Dermatology Department at J.S.S Hospital. Methods: This study was conducted at JSS Medical College and Hospital from December 2016 to December 2017. Clinical samples (e.g., skin scrapings and hair stumps) were collected under aseptic precautions. The identification of dermatophytes was performed through microscopic examination using 10%, 20% & 40% potassium hydroxide (KOH) and culture on Sabouraud dextrose agar (SDA), SDAac, PDA and Dermatophyte test medium (DTM). All dermatophytes isolates were subjected to antifungal susceptibility testing using the agar-based disk diffusion (ABDD) and E-test method against Terbinafine, Itraconazole, Fluconazole, and Griseofulvin. Data were analyzed by using Chi square test. Results: A 100 samples were studied, 46% tinea corporis, 2%tinea cruris, 9% tinea pedis, 5% tinea faciei. The dermatophytes isolated were Trichophyton rubrum 11 (35%), Trichophyton mentagrophyte 8 (25%), Trichophyton tonsurans 5 (16%), Microsporum gypseum 3 (10%), Trichophyton verrucosum 2 (6%), Trichophyton violaceum 1 (3%) and Microsporum audouinii 1 (3%). Out of 31 dermatophytes 17 were sensitive to all four antifungal agents within the range of FLC (2 - 6 mcg/ml), ITR (0.125 - 2), TER (0.125 - 2), and GRI (0.125 - 2), 5 isolates were resistant in which 2 were resistant to FLC (64.256 mcg/ml), 2 isolates were resistant to TER 2 (32.38 mcg/ml), 1 isolate was resistant to both GRI and TER (16.32 mcg/ml) and 9 isolates were within the intermediate range. Conclusion: Every patient with a tinea infection should be properly studied for a mycological examination and should be treated accordingly. Dermatophyte test medium is more useful as an identification medium in the isolation of dermatophytes. The ABDD method appears to be a simple, cost-effective, and promising method for the evaluation of antifungal susceptibility of dermatophytes. E-test method is the most sensitive method due to the fact that quantitative MICs can be obtained directly from the E-strip. However, the E-test method is expensive and difficult in defining the precise borders of the inhibition zones in dermatophytes.

Green Synthesis of Highly Dispersed Zinc Oxide Nanoparticles Supported on Silica Gel Matrix by Daphne oleoides Extract and their Antibacterial Activity.

Background: ZnO nanoparticles (ZnO-NPs) are one of the most popular metal oxide nanoparticles, which exhibit significant antibacterial properties against various pathogens. Among nanoparticle synthesis methods, the green synthesis using plant extract is considered as an eco-friendly and cost-effective method for ZnO-NPs production, compared to the chemical procedures.Background: This study aimed to evaluate the green synthesis of ZnO-NPs loaded on silica gel matrix (ZnO/SG nanocomposite) by using methanol leaf extract of Daphne oleoides as a new extract and a cost-effective method. Furthermore, the antibacterial activity of the synthesized structure is evaluated against some pathogenic bacteria and the results are compared with unsupported ZnO-NPs.Materials and Methods: For ZnO/SG nanocomposite synthesis, a solution of Zn (NO3)2 was stirred with silica gel. Then the Daphne oleoides extract was added and stirred continuously until white precipitate was formed. The precipitate was heated at 200 ˚C for calcination, and ZnO/SG nanocomposite was obtained. The phytochemical constituents of leaf extract were then analyzed by gas chromatography–mass spectrometry (GC-MS). Afterwards, the structure of ZnO-NPs on SiO2 matrix (ZnO/SG nanocomposite) was characterized by field emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction analysis (XRD), and Fourier transform infrared spectroscopy (FTIR). Surface area measurement was also determined by Brunauer-Emmett-Teller (BET) techniques. Furthermore, the antibacterial activity of ZnO/SG nanocomposites against pathogenic bacteria was evaluated using agar-based disk diffusion method standardized by clinical and laboratory guidelines. Results: The leaf extract of Daphne oleoides encompassed five major polyphenolic components. The results of the nanocomposite structure showed that ZnO-NPs with an average particle size of 38 nm were obtained and stabilized on the silica gel matrix. The BET surface area measurement of ZnO/SG nanocomposite was compared with unsupported ZnO-NPs, and the results indicated that the surface area of ZnO/SG nanocomposite was increased. Furthermore, the structure showed more powerful antibacterial activity against pathogens than unsupported ZnO-NPs. Conclusions: Green synthesis of ZnO-NPs supported on the silica gel matrix with the leaf extract of Daphne oleoides is a benign and effective procedure for ZnO/SG nanocomposite synthesis. Embedding ZnO-NPs in silica gel matrix prevents the agglomeration of nanoparticles and prepare homodispersed nanoparticles. This structure revealed great antibacterial activity against many pathogens.

Synthesis, Characterization and in vitro Antimicrobial Evaluation of Pyrazole Based Oxothiazolidine Hybrids

In this work, pyrazole based oxothiazolidine hybrids, 4-{4-[2-(1-phenyl-3-(substituted)phenyl-1H-pyrazol-4-yl)-4-oxo-thiazolidin-3-yl]-phenyl}-morpholin-3-one (11a-l) were synthesized using molecular hybridization approach through Vilsmeier-Haack reaction. The titled compounds 11a-l were characterized by elemental analysis, IR, 1H NMR and mass spectral studies. The antibacterial activity of 11a-l was evaluated in vitro by agar cup plate method against B. cocous, B. subtillis, E. coli and P. vulgaris. The antifungal activity of compounds 11a-l was evaluated in vitro by agar based disk diffusion method against A. niger. The results of antibacterial and antifungal evaluation were reported in terms of zone of inhibition measured in mm. The synthesized compounds 11a-l exhibited moderate to good antibacterial and antifungal potential. Compound 4-{4-[2-(1-phenyl-3-(2-methoxyphenyl)phenyl-1H-pyrazol-4-yl)-4-oxo-thiazolidin-3-yl]-phenyl}-morpholin-3-one (11h) emerged as a most potent antimicrobial agent displaying zone of inhibition 21, 20, 21, 24 and 20 mm against B. cocous, B. subtillis, E. coli, P. vulgaris and A. niger, respectively.

Assessment of resistance in common bean to Fusarium oxysporum f. sp. phaseoli using different inoculation and evaluation methods

This study aimed to evaluate the resistance of three common bean genotypes (BRS Estilo, A211 and Mortiño) to the Fusarium oxysporum f. sp. phaseoli using different inoculation methods such as the root-dip, the colonized toothpick, and the agar-based disk-diffusion. After 35 days of inoculation, the disease severity was assessed by vascular discoloration on the stem of the plants by two methods: using a scoring scale and measuring the length of the discoloration with the aid of a millimeter ruler (cm). Results showed that the root-dip was the most effective inoculation method. As for the method of assessing the disease severity, the scoring scale was the best one, in addition to being easier for evaluating large amounts of common bean lines.

Actinobacteria Isolated From Laminaria ochroleuca: A Source of New Bioactive Compounds

Nature is the major reservoir of biologically active molecules. The urgent need of finding novel molecules for pharmaceutical application is prompting the research of underexplored environments, such as marine ecosystems. Here, we investigated cultivable actinobacteria associated with the macroalgae Laminaria ochroleuca and assessed their potential to produce compounds with antimicrobial or anticancer activities. A specimen of L. ochroleuca was collected in a rocky shore in northern Portugal, and fragments of tissues from different parts of the macroalgae (holdfast, stipe, and blades) were surface sterilized and plated in three culture media selective for actinobacteria. A total of 90 actinobacterial strains were isolated, most of which affiliated with the genus Streptomyces. Isolates associated with the genera Isoptericola, Rhodococcus, Nonomuraeae, Nocardiopsis, Microbispora, and Microbacterium were also obtained. Organic extracts from the isolates were tested for their antimicrobial activity using the agar-based disk diffusion method, followed by determination of minimum inhibitory concentration (MIC) values. Forty-five isolates inhibited the growth of Candida albicans and/or Staphylococcus aureus, with MIC values ranging from <0.5 to 1000 μg mL−1. The actinobacterial isolates were also tested for their anticancer potential on two human cancer cell lines. Twenty-eight extracts affected the viability of at least one human cancer cell line (breast carcinoma T-47D and neuroblastoma SH-SY5Y) and non-carcinogenic endothelial cell line (hCMEC/D3). Seven extracts affected the viability of cancer cells only. This study revealed that L. ochroleuca is a rich source of actinobacteria with promising antimicrobial and anticancer activities and suggests that macroalgae may be a valuable source of actinobacteria and, consequently, of new molecules with biotechnological importance.

Alanine rich peptide from Populus trichocarpa inhibit growth of Staphylococcus aureus via targetting its extracellular domain of Sensor Histidine Kinase YycGex protein

BackgroundDue to growing concern towards microbial resistance, ongoing search for developing novel bioactive compounds such as peptides is on rise. The aim of this study was to evaluate antimicrobial effect of Populus trichocarpa extract, chemically identify the active peptide fraction and finds its target in Staphylococcus aureus. MethodsIn this study the active fraction of P. trichocarpa crude extract was purified and characterized using MS/MS. This peptide PT13 antimicrobial activity was confirmed by in-vitro agar based disk diffusion and in-vivo infection model of G. mellonella. The proteomic expression analysis of S. aureus under influence of PT13 was studied using LTQ-Orbitrap-MS in-solution digestion and identity of target protein was acquired with their quantified expression using label-free approach of Progenesis QI software. Docking study was performed with peptide PT13 and its target YycG protein using CABS-dock. ResultsThe active fraction PT13 sequence was identified as KVPVAAAAAAAAAVVASSMVVAAAK, with 25 amino acid including 13 alanine having M/Z 2194.2469. PT13 was uniformly inhibited growth S. aureus SA91 and MIC was determined 16 μg/mL for SA91 S. aureus strain. Sensor histidine kinase (YycG) was most significant target found differentially expressed under influence of PT13. G. mellonella larvae were killed rapidly due to S aureus infection, whereas death in protected group was insignificant in compare to control. The docking models showed ten docking models with RMSD value 1.89 for cluster 1 and RMSD value 3.95 for cluster 2 which is predicted to be high quality model. ConclusionAlanine rich peptide could be useful in constructing as antimicrobial peptide for targeting extracellular Domain of Sensor Histidine Kinase YycG from S. aureus used in the study.

Acute and chronic toxicity and antimicrobial activity of the extract of Stryphnodendron adstringens (Mart.) Coville

ABSTRACT: This study evaluated the antimicrobial activity and acute or chronic toxicity of the extract of Stryphnodendron adstringens. The stem bark dry extract was obtained by static maceration with ethanol. Quantification of tannins was performed by the Folin-Denis method, which indicated a total tannin content of 32.7%. The antimicrobial activity of the dry extract of S. adstringens was evaluated by agar-based disk diffusion assay with Escherichia coli (ATCC 25922) and Staphylococcus aureus (ATCC 25923) in the concentration of 200, 400 and 600μL/mL. The results indicated that 600μL/mL inhibited microbial growth, i.e. had antimicrobial activity against these species. Acute and chronic toxic effects of S. adstringens was evaluated in Wistar rats treated with 200, 400, 600 and 800mg/kg of extract, administrated by gavage. Liver degeneration was observed in the group of rats receiving 800mg/kg in chronic exposure, what may indicate some degree of toxicity at this concentration. However, no systemic toxicity was observed at lower doses. Considering the broad use of S. adstringens as a phytotherapeutic agent for various human and animal diseases and the livertoxicity observed at high concentrations, attention should be paid to the possible adverse effect of using the extract from this plant at high concentration.

Antifungal Susceptibility Testing of Dermatophytes by Agar Based Disk Diffusion Assay in Tertiary Care Hospital, Nepal

Antifungal Susceptibility Testing of Dermatophytes by Agar Based Disk Diffusion Assay in Tertiary Care Hospital, Nepal

Oxidatively Locked [Co₂L₃]6+ Cylinders Derived from Bis(bidentate) 2-Pyridyl-1,2,3-triazole "Click" Ligands: Synthesis, Stability, and Antimicrobial Studies.

A small family of [Co2(Lpytrz)3]6+ cylinders was synthesised from bis(bidentate) 2-pyridyl-1,2,3-triazole “click” ligands (Lpytrz) through an “assembly-followed-by-oxidation” method. The cylinders were characterised using 1H, 13C, and DOSY NMR, IR, and UV-Vis spectroscopies, along with electrospray ionisation mass spectrometry (ESMS). Stability studies were conducted in dimethyl sulfoxide (DMSO) and D2O. In contrast to similar, previously studied, [Fe2(Lpytrz)3]4+ helicates the more kinetically inert [Co2(Lpytrz)3]6+ systems proved stable (over a period of days) when exposed to DMSO and were even more stable in D2O. The triply stranded [Co2(Lpytrz)3]6+ systems and the corresponding “free” ligands were tested for antimicrobial activity in vitro against both Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) microorganisms. Agar-based disk diffusion and Mueller–Hinton broth micro-dilution assays showed that the [Co2(Lpytrz)3]6+ cylinders were not active against either strain of bacteria. It is presumed that a high charge of the [Co2(Lpytrz)3]6+ cylinders is preventing them from crossing the bacterial cell membranes, rendering the compounds biologically inactive.

Antimicrobial Properties of Tris(homoleptic) Ruthenium(II) 2-Pyridyl-1,2,3-triazole "Click" Complexes against Pathogenic Bacteria, Including Methicillin-Resistant Staphylococcus aureus (MRSA).

A series of tris(homoleptic) ruthenium(II) complexes of 2-(1-R-1H-1,2,3-triazol-4-yl)pyridine "click" ligands (R-pytri) with various aliphatic (R = butyl, hexyl, octyl, dodecyl, and hexdecyl) and aromatic (R = phenyl and benzyl) substituents was synthesized in good yields (52%-66%). The [Ru(R-pytri)3]2+(X-)2 complexes (where X- = PF6- or Cl-) were characterized by elemental analysis, high-resolution electrospray ionization mass spectrometry (HR-ESI-MS), 1H and 13C nuclear magnetic resonance (NMR) and infrared (IR) spectroscopies, and the molecular structures of six of the compounds confirmed by X-ray crystallography. 1H NMR analysis showed that the as-synthesized materials were a statistical mixture of the mer- and fac-[Ru(R-pytri)3]2+ complexes. These diastereomers were separated using column chromatography. The electronic structures of the mer- and fac-[Ru(R-pytri)3]2+ complexes were examined using ultraviolet-visible (UV-Vis) spectroscopy and cyclic and differential pulse voltammetry. The family of R-pytri ligands and the corresponding mer- and fac-[Ru(R-pytri)3]2+ complexes were tested for antimicrobial activity in vitro against both Staphylococcus aureus and Escherichia coli bacteria. Agar-based disk diffusion assays indicated that two of the [Ru(R-pytri)3](X)2 complexes (where X = PF6- and R = hexyl or octyl) displayed good antimicrobial activity against Gram-positive S. aureus and no activity against Gram-negative E. coli at the concentrations tested. The most active [Ru(R-pytri)3]2+ complexes ([Ru(hexpytri)3]2+ and Ru(octpytri)3]2+) were converted to the water-soluble chloride salts and screened for their activity against a wider range of pathogenic bacteria. As with the preliminary screen, the complexes showed good activity against a variety of Gram-positive strains (minimum inhibitory concentration (MIC) = 1-8 μg/mL) but were less effective against Gram-negative bacteria (MIC = 16-128 μg/mL). Most interestingly, in some cases, the ruthenium(II) "click" complexes proved more active (MIC = 4-8 μg/mL) than the gentamicin control (MIC = 16 μg/mL) against two strains of methicillin-resistant S. aureus (MRSA) (MR 4393 and MR 4549). Transmission electron microscopy (TEM) experiments and propidium iodide assays suggested that the main mode of action for the ruthenium(II) R-pytri complexes was cell wall/cytoplasmic membrane disruption. Cytotoxicity experiments on human dermal keratinocyte and Vero (African green monkey kidney epithelial) cell lines suggested that the complexes were only modestly cytotoxic at concentrations well above the MIC values.

Isolation, Identification, and In Vitro Antifungal Susceptibility Testing of Dermatophytes from Clinical Samples at Sohag University Hospital in Egypt.

AimThe objective of this study was to isolate, identify, and explore the in-vitro antifungal susceptibility pattern of dermatophytes isolated from clinically suspected cases of dermatophytosis (tinea infections) attending the Dermatology Outpatient Clinic.MethodsThis study was conducted at Sohag University Hospital from December 2014 to December 2015. Clinical samples (e.g., skin scrapings and hair stumps) were collected under aseptic precautions. The identification of dermatophytes was performed through microscopic examination using 10% potassium hydroxide (KOH) with 40% dimethyl sulphoxide (DMSO) mounts and culture on Sabouraud dextrose agar (SDA) and on Dermasel agar base media, both supplemented with chloramphenicol and cycloheximide. All dermatophytes isolates were subjected to antifungal susceptibility testing using the agar-based disk diffusion (ABDD) method against Clotrimazole, Miconazole, Fluconazole, and Griseofulvin. Data were analyzed via SPSS 16, using Chi square and a screening test (cross-tabulation method).ResultsA total of 110 patients of dermatophytosis were studied. The patients were clinically diagnosed and mycologically confirmed as having tinea capitis (49), tinea corporis (30), tinea pedis (16), tinea cruris (9), or tinea barbae (6). The dermatophytes isolates belonged to 4 species: Microsporum canis 58 (52.7%), Microsporum gypseum 23 (20.9%), Trichophyton mentagrophytes 18 (16.4%), and Microsporum audouinii 11 (10%). The most effective antifungal drugs tested were Clotrimazole, followed by Miconazole (95.5% and 84.5% of isolates were susceptible, respectively).ConclusionEvery patient with a tinea infection should be properly studied for a mycological examination and should be treated accordingly. Dermasel agar is more useful as an identification medium in the isolation of dermatophytes. The ABDD method appears to be a simple, cost-effective, and promising method for the evaluation of antifungal susceptibility of dermatophytes.

Antimicrobial Properties of Mono- and Di-fac-rhenium Tricarbonyl 2-Pyridyl-1,2,3-triazole Complexes

A family of mono- and di-fac-rhenium tricarbonyl 2-pyridyl-1,2,3-triazole complexes with different aliphatic and aromatic substituents was synthesized in good-to-excellent yields (46–99 %). The complexes were characterized by 1H and 13C NMR spectroscopy, infrared spectroscopy, electronic (UV-visible) spectroscopy, high-resolution electrospray mass spectrometry, and elemental analyses. In four examples, the solid-state structures of the rhenium(i) complexes were confirmed by X-ray crystallography. The family of the mono- and di-rhenium(i) complexes and the corresponding 2-pyridyl-1,2,3-triazole was tested for antimicrobial activity in vitro against both Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) microorganisms. Agar-based disk diffusion assays indicated that most of the rhenium(i) complexes were active against Staphylococcus aureus and that the cationic rhenium(i) complexes were more active than the related neutral systems. However, in all cases, the minimum inhibitory concentrations for all the complexes were modest (i.e. 16–1024 µg mL–1).

English

Superficial mycosis with dermatophytes has a wide geographical distribution and diverse species prevalence. This mycological study comprised of 204 clinically suspected cases of dermatophytosis. All 204 samples were subjected to direct microscopy by potassium hydroxide (KOH) mount and isolation on Sabouraud's dextrose agar containing chloramphenicol without cycloheximide. Culture confirmation was done by tease mount, slide culture and various physiological tests like urease test, hair perforation test etc. In the present study an agar based disk diffusion method was performed to determine the susceptibility of dermatophytes. In this study 49% cases were positive for fungus in microscopy, while 24% was culture positive. The most common clinical types observed was T. cruris (40%) followed by T. corporis (34.3%). Young adults in the age group of 21-30 years were most commonly affected, belonging to lower middle socio-economic status. Among cultures, T. rubrum was the most common isolate (53%) followed by T. mentagrophyte (38.7%).

Synthesis, structure, stability and antimicrobial activity of a ruthenium(II) helicate derived from a bis-bidentate “click” pyridyl-1,2,3-triazole ligand

A [Ru2L3]4+ ruthenium(II) triply-stranded helicate was synthesized from a bis-bidentate “click” pyridyl-1,2,3-triazole ligand and RuCl3 in good yield (58%). The helicate was characterized by elemental analysis, IR, UV–Vis, 1H, 13C and 1H DOSY NMR spectroscopies and the molecular structure confirmed using X-ray crystallography. In contrast to similar, previously studied, [Fe2L3]4+ helicates the more kinetically inert [Ru2L3]4+ system proved stable (over a period of days) when exposed to either dimethyl sulfoxide (DMSO) or a DMSO solution of the common biological ligand histidine. The [Ru2L3]4+ helicate and the corresponding “free” ligand were tested for antimicrobial activity in vitro against both Gram positive (Staphylococcus aureus) and Gram negative (Escherichia coli) microorganisms. Agar-based disk diffusion assays indicated that the Ru(II) helicate displayed antimicrobial activity but the minimum inhibitory concentrations (MIC) proved to be extremely modest (MIC>256μg/mL).

Re(CO)3]+ Complexes of exo-Functionalized Tridentate “Click” Macrocycles: Synthesis, Stability, Photophysical Properties, Bioconjugation, and Antibacterial Activity

There is considerable interest in the development of bifunctional ligand scaffolds for the group 7 metals due to potential biological applications. Building on our recent work in the development of “click” ligands and macrocycles, we show that a CuAAC “click” approach can be exploited for the synthesis of a small family of bioconjugated tridentate pyridyl-1,2,3-triazole macrocycles. These bioconjugated tridentate macrocycles form stable [Re(CO)3]+ complexes, and this could facilitate the development of [M(CO)3]+ (M = Mn, Tc, Re) targeted agents. The parent macrocycle, bioconjugates, and [Re(CO)3]+ complexes were characterized by elemental analysis and HR-ESI-MS, 1H and 13C NMR, and IR spectroscopy, and the molecular structures of the alcohol-functionalized macrocycle and two of the Re(I) complexes were confirmed by X-ray crystallography. The electronic structure of the parent [Re(CO)3]+ macrocycle complex was examined using UV–vis, Raman, and emission spectroscopy and density functional theory calculations. The complex exhibited intense absorptions in the UV region which were modeled using time-dependent density functional theory (TD-DFT). The calculations suggest that the lower energy part of the absorption band is MLCT in nature and additional higher energy π–π* transitions are present. The complex was weakly emissive at room temperature in methanol with a quantum yield of 5.1 × 10–3 and correspondingly short excited state lifetime (τ ≈ 20 ns). The family of macrocycles and the corresponding Re(I) complexes were tested for antimicrobial activity in vitro against both Gram positive (Staphylococcus aureus) and Gram negative (Escherichia coli) microorganisms. Agar-based disk diffusion assays indicated that two of the Re(I) complexes displayed antimicrobial activity but the minimum inhibitory concentrations (MIC) for these compounds proved to be extremely modest (MIC > 256 μg/mL).