Design, synthesis, antimicrobial activity and molecular docking study of cationic bis-benzimidazole-silver(I) complexes.

Two series of bis(1-alkylbenzimidazole)silver(I) nitrate and bis(1-alkyl-5,6-dimethylbenzimidazole)silver(I) nitrate complexes, in which the alkyl substituent is either an allyl, a 2-methylallyl, an isopropyl or a 3-methyloxetan-3-yl-methyl chain, were synthesized and fully characterized. The eight N-coordinated silver(I) complexes were screened for both antimicrobial activities against Gram-negative (Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae, and Acinetobacter baumannii) and Gram-positive (Staphylococcus aureus, Staphylococcus aureus MRSA, and Enterococcus faecalis) bacteria and antifungal activities against Candida albicans and Candida glabrata strains. Moderate minimal inhibitory concentrations (MIC) of 0.087 µmol/mL were found when the Gram-negative and Gram-positive bacteria were treated with the silver complexes. Nevertheless, MIC values of 0.011 µmol/mL, twice lower than for the well-known fluconazole, against the two fungi were measured. In addition, molecular docking was carried out with the structure of Escherichia coli DNA gyrase and CYP51 from the pathogen Candida glabrata with the eight organometallic complexes, and molecular reactivity descriptors were calculated with the density functional theory-based calculation methods.

Evaluation of cytotoxic, antifungal, and larvicidal activities of different bis-sulfonamide Schiff base compounds.

Schiff bases (imines or azomethines) are versatile ligands synthesized from the condensation of amino compounds with active carbonyl groups and used for many pharmaceutical and medicinal applications. In our study, we aimed to determine the cytotoxic, antifungal and larvicidal activities of biologically potent bis-sulfonamide Schiff base derivatives that were re-synthesized by us. For this aim, 16 compounds were re-synthesized and tested for their cytotoxic, antifungal and larvicidal properties. Among this series, compounds A1B2, A1B4, A4B2, A4B3, and A4B4 were shown to have cytotoxic activity against tested cancer lung cell line (A549). The most potent antifungal activity was observed in compounds A2B1 and A2B2 against all fungi. A1B1 showed the strongest larvicidal effect at all concentrations at the 72nd h (100% mortality). These obtained results demonstrate that these type of bis-substituted compounds might be used as biologically potent pharmacophores against different types of diseases.

Cyanopropyl functionalized benzimidazolium salts and their silver N-heterocyclic carbene complexes: Synthesis, antimicrobial activity, and theoretical analysis.

The reaction of N-substituted benzimidazole with 4-bromobutyronitrile gives the corresponding benzimidazolium salts as N-heterocyclic carbene (NHC) precursors. Silver(I) carbene complexes are synthesized by the reaction of the corresponding benzimidazolium salts with Ag2 O in dichloromethane. These new NHC precursors and Ag-NHC complexes were characterized by spectroscopy techniques and also screened for their antibacterial activities against the standard bacterial strains Escherichia coli, Pseudomonas aeruginosa, Acinetobacter baumannii, Klebsiella pneumoniae, Staphylococcus aureus, methicillin-resistant Staphylococcus aureus, and Enterococcus faecalis, and the standard fungal strains Candida albicans and Candida glabrata, and promising results were achieved. The compounds were also analyzed by density functional theory (DFT)/time-dependent DFT and docking methods.

Water-soluble silver(i) complexes with N-donor benzimidazole ligands containing an imidazolium core: stability and preliminary biological studies.

Herein, we report the synthesis, characterisation and preliminary biological evaluation of two novel silver(i) complexes of type [AgL2](NO3)3 (3 and 4) with ionic N-donor benzimidazoles. The complexes have been synthesized by the reaction of 1.5 equivalents of silver nitrate and N-donor benzimidazoles containing an imidazolium core at the 2-position (1 and 2) in ethanol. The X-ray analysis of 4 shows that it has two free imidazolium cores and the charge is balanced with three nitrate anions. A study by the combination of NMR, IR, LC-MS and elemental analysis techniques also suggests that the complexes have this structure both in the solid-state and solution. The complexes are highly soluble and stable in water. Cytotoxicity evaluation against four cancerous human cells and one non-cancerous human cell revealed that the complexes have no significant anti-growth effect. However, the complexes showed a remarkable antimicrobial effect at normalized minimum inhibitory concentrations (normalized MICs) in the range of 33-268 µM against a panel of microorganisms consisting of Gram-negative and Gram-positive bacteria, and fungi.

Catechol-bearing imidazolium and benzimidazolium chlorides as promising antimicrobial agents.

Catechol-containing imidazolium (four) and benzimidazolium chlorides (eight) were synthesized to evaluate their antimicrobial properties. All the compounds were fully characterized using 1 H and 13 C nuclear magnetic resonance, liquid chromatography-mass spectrometry, infrared spectroscopic methods, and elemental analyses. Antimicrobial activities of the compounds were tested against the bacteria Escherichia coli, Pseudomonas aeruginosa, Acinetobacter baumannii, Klebsiella pneumoniae, Staphylococcus aureus, methicillin-resistant S. aureus (MRSA), Enterococcus faecalis, and the fungal strains Candida albicans and Candida glabrata, and promising results were achieved. The two most important benzyl-substituted benzimidazolium chlorides, 3l and 3k, showed comparable activity to vancomycin against MRSA.

Novel benzimidazol-2-ylidene carbene precursors and their silver(I) complexes: Potential antimicrobial agents.

Novel benzimidazolium salts were synthesized as N-heterocyclic carbene (NHC) precursors, these NHC precursors were metallated with Ag2O in dichloromethane at room temperature to give novel silver(I)-NHC complexes. Structures of these benzimidazolium salts and silver(I)-NHC complexes were characterized on the basis of elemental analysis, (1)H NMR, (13)C NMR, IR and LC-MS spectroscopic techniques. A series of benzimidazolium salts and silver(I)-NHC complexes were tested against standard bacterial strains: Enterococcus faecalis, Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa and the fungal strains: Candida albicans and Candida tropicalis. The results showed that benzimidazolium salts inhibited the growth of all bacteria and fungi strains and all silver(I)-NHC complexes performed good activities against different microorganisms.

Benzimidazolium-based novel silver N-heterocyclic carbene complexes: synthesis, characterisation and in vitro antimicrobial activity.

This study reports the synthesis, characterisation and antimicrobial activity of five novel silver N-heterocyclic carbene (Ag-NHC) complexes obtained by N-propylphthalimide and N-methyldioxane substituted benzimidazolium salts with silver oxide. The reactions were performed at room temperature for 24 h in the absence of light. The obtained complexes were identified and characterised by (1)H and (13)C NMR, FT-IR and elemental analysis techniques. The minimum inhibitory concentration (MIC) of the complexes was determined for E. coli, P. aeruginosa, E. faecalis, S. aureus, C. tropicalis and C. albicans in vitro through agar and broth dilution. The results indicated that these complexes exhibit antimicrobial activity. In particular, complex 3 presented the significant broad spectrum antimicrobial activity.

Synthesis, characterization and antimicrobial activities of novel silver(I) complexes with coumarin substituted N-heterocyclic carbene ligands.

Eight new coumarin substituted silver(I) N-heterocyclic carbene (NHC) complexes were synthesized by the interaction of the corresponding imidazolium or benzimidazolium chlorides and Ag2O in dichloromethane at room temperature. Structures of these complexes were established on the basis of elemental analysis, (1)H NMR, (13)C NMR, IR and mass spectroscopic techniques. The antimicrobial activities of carbene precursors and silver NHC complexes were tested against standard strains: Enterococcus faecalis, Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa and the fungi Candida albicans and Candida tropicalis. Results showed that all the compounds inhibited the growth of the all bacteria and fungi strains and some complexes performed good activities against different microorganisms. Among all the compounds, the most lipophilic complex bis[1-(4-methylene-6,8-dimethyl-2H-chromen-2-one)-3-(naphthalene-2-ylmethyl)benzimidazol-2-ylidene]silver(I) dichloro argentate (5e) was found out as the most active one.

Synthesis, antioxidant and anti-microbial properties of two organoselenium compounds.

The aim of this study is synthesis of two different series of organoselenium compounds and available in vitro antioxidant and antimicrobial properties of these synthetic compounds. The synthetic compounds were identified by (1)H-NMR (300 MHz), (13)C-NMR (75.5 MHz), FT-IR spectroscopic techniques and micro analysis. Antioxidant properties of two synthetic organoselenium compounds were determined by 1,1- diphenyl-2-picrylhydrazyl (DPPH) radical method, reducing power assay and ß-carotene bleaching method as in vitro. Antimicrobial effects of samples were assessed by the agar dilution procedure and using gram positive and gram-negative bacteria and yeast strains. Although 1,3-di-p-methoxybenzylpyrimidine-2-selenone showed better antiradical activity in DPPH test and higher protective activity on ß-carotene, 1-isopropyl-3-methylbenzimidazole-2-selenone was found to be better in reducing power and antimicrobial activity.

Comparison of keypads and touch-screen mobile phones/devices as potential risk for microbial contamination.

INTRODUCTION: Touch-screen mobile phones/devices (TMPs/Ds) are increasingly used in hospitals. They may act as a mobile reservoir for microbial pathogens. The rates of microbial contamination of TMPs/Ds and keypad mobile phones (KMPs) with respect to different variables including use by healthcare workers (HCWs)/non-HCWs and the demographic characteristics of users were investigated. METHODOLOGY: A total of 205 mobile phones/devices were screened for microbial contamination: 76 devices belonged to HCWs and 129 devices belonged to the non-HCW group. By rubbing swabs to front screen, back, keypad, and metallic surfaces of devices, 444 samples were collected. RESULTS: Of 205 mobile phones/devices, 143 (97.9%) of the TMPs/Ds and 58 (98.3%) of the KMPs were positive for microbial contamination, and there were no significant differences in contamination rates between these groups, although TMPs/Ds had significantly higher microbial load than KMPs (p <0.05). The significant difference in this analysis was attributable to the screen size of mobile phones ≥ 5". Microbial contamination rates increased significantly as phone size increased (p <0.05). Higher numbers of coagulase-negative Staphylococci (CNS) were isolated from KMPs than TMPs/Ds (p = 0.049). The incidence of Enterococcus spp. was higher on the KMPs of HCWs, and methicillin resistant CNS was higher from the TMPs/Ds of non-HCWs (p <0.05). Isolation of CNS, Streptococcus spp. and Escherichia coli was higher from the TMPs/Ds of HCWs (p <0.05). CONCLUSIONS: We found no significant difference between TMP/Ds and KMPs in terms of microbial contamination, but TMP/Ds harboured more colonies and total microbial counts increased with screen size.

Synthesis, anticonvulsant and antimicrobial activities of some new [1-(2-naphthyl)-2-(pyrazol-1-yl)ethanone]oxime ethers.

In this study, 12 new oxime ether derivatives, which were expected to show anticonvulsant and antimicrobial activities, were synthesized. Oxime ether derivatives were synthesized by the reaction of various alkyl halides with 1-(2- naphthyl)-2-(pyrazol-1-yl)ethanone oxime. Anticonvulsant activity of the compounds was determined by maximal electroshock (MES) and subcutaneous metrazol (ScM) seizure tests, while neurological disorders were evaluated using rotorod toxicity test according to the ASP of NIH. Compound 1, 6 and 7 showed anticonvulsant activity at 300 mg/kg dose at 4 h, but compounds 1 and 7 showed toxicity at 300 mg/kg dose at half an hour. Antimicrobial activities of the compounds were also determined using agar microdilution method. Compound 1 and 5 were found to have the highest antifungal activity among the other compounds.

Antioxidant and antimicrobial activities, and phenolic compounds of selected Inula species from Turkey.

Three Inula species, I. viscosa, I. helenium ssp. turcoracemosa and I. montbretiana, collected from different locations of Anatolia were investigated for their antioxidant and antimicrobial potential, and their total phenolic content and phenolic composition. Antioxidant activities of various extracts of the plant parts were measured using DPPH radical scavenging and ABTS assays. Antimicrobial potential of methanol extracts of the plant parts was determined by the agar dilution method against Staphylococcus aureus, Enterococcus faecalis, Escherichia coli, Pseudomonas aeruginosa, Candida albicans and Candida tropicalis. All the extracts were more active against Gram-positive bacteria and yeasts than Gram-negative bacteria. The extracts exhibited antioxidant and antimicrobial activities in different concentrations. Total phenolic concentration of the extracts was estimated with Folin-Ciocalteu reagent using gallic acid as standard. The total phenolic content varied widely in different parts of the three tested Inula species, ranging from 21.1 +/- 0.8 to 190.9 +/- 6.1 mg GAE/g extract. Phenolic components, such as chlorogenic acid, caffeic acid, rutin, myricetin, quercetin, luteolin and kaempferol were quantified by HPLC-DAD in the methanol extracts of the Inula species. It was obvious that the antioxidant and antimicrobial properties of the plants were due to the phenolics.

[Isolation and identification of Mycobacterium bovis and non-tuberculous mycobacteria in raw milk samples in Mersin province]. / Mersin Ilinde Çig Sütlerden Mycobacterium bovis ve Tüberküloz Disi Mikobakterilerin Izolasyonu ve Tanimlanmasi

This study was aimed to isolate and identify Mycobacterium bovis and non-tuberculous mycobacteria (NTM) species in raw milk samples from cattles and to compare the diagnostic performance of the methods used for that purpose. A total of 145 raw milk samples from cattles were collected from five villages in Mersin province (located on Mediterrenean region of Turkey) between April and June 2008. Presence of mycobacteria was investigated by Ehrlich Ziehl Neelsen (EZN) staining method, culture in Löwenstein- Jensen (LJ) medium and polymerase chain reaction (PCR). Only 1 (0.7%, 1/145) raw milk sample was found to be acid fast bacilli (AFB) positive with EZN staining. Eleven (7.6%) samples were positive by culture and mycobacterial DNA was detected in 6 (4.1%) samples by PCR. Mycobacterium was isolated from both creamy and pellet layer of a culture positive sample. Identification was carried out with conventional biochemical tests, PCR-Restriction Fragment Length Polymorphisms (PCR-RFLP) and spoligotyping (spacer oligonucleotide typing) methods. One isolate was identified as Mycobacterium tuberculosis complex (MTC) and 11 isolates were identified as NTM out of 12 isolates those were isolated from culture. According to PCR-RFLP analysis of these 11 NTM isolates, 6 (54.5%) were Mycobacterium genavense, 2 (18.2%) were Mycobacterium simiae, 2 (18.2%) were Mycobacterium szulgai and 1 (9.1%) was Mycobacterium fortuitum. MTC isolate was identified as M.bovis by spoligotyping. According to the results of our study, both pellet and creamy layers from raw milk samples should be cultured to selective LJ medium (without glycerol, with 0.4% sodium pyruvate) to improve the chance of isolation and must be incubated for up to eight weeks. In our region, NTM were isolated in 6.9% and M.bovis in 0.7% of the raw milk samples from cattles and this emphasized the risk of transmission of mycobacteria to man via direct contact or ingestion of unpasteurized milk products.

Distribution of spoligotyping defined genotypic lineages among drug-resistant Mycobacterium tuberculosis complex clinical isolates in Ankara, Turkey.

BACKGROUND: Investigation of genetic heterogeneity and spoligotype-defined lineages of drug-resistant Mycobacterium tuberculosis clinical isolates collected during a three-year period in two university hospitals and National Tuberculosis Reference and Research Laboratory in Ankara, Turkey. METHODS AND FINDINGS: A total of 95 drug-resistant M. tuberculosis isolates collected from three different centers were included in this study. Susceptibility testing of the isolates to four major antituberculous drugs was performed using proportion method on Löwenstein-Jensen medium and BACTEC 460-TB system. All clinical isolates were typed by using spoligotyping and IS6110-restriction fragment length polymorphism (RFLP) methods. Seventy-three of the 95 (76.8%) drug resistant M. tuberculosis isolates were isoniazid-resistant, 45 (47.4%) were rifampicin-resistant, 32 (33.7%) were streptomycin-resistant and 31 (32.6%) were ethambutol-resistant. The proportion of multidrug-resistant isolates (MDR) was 42.1%. By using spoligotyping, 35 distinct patterns were observed; 75 clinical isolates were grouped in 15 clusters (clustering rate of 79%) and 20 isolates displayed unique patterns. Five of these 20 unique patterns corresponded to orphan patterns in the SITVIT2 database, while 4 shared types containing 8 isolates were newly created. The most prevalent M. tuberculosis lineages were: Haarlem (23/95, 24.2%), ill-defined T superfamily (22/95, 23.2%), the Turkey family (19/95, 20%; previously designated as LAM7-TUR), Beijing (6/95, 6.3%), and Latin-America & Mediterranean (LAM, 5/95 or 5.3%), followed by Manu (3/95, 3.2%) and S (1/95, 1%) lineages. Four of the six Beijing family isolates (66.7%) were MDR. A combination of IS6110-RFLP and spoligotyping reduced the clustering rate from 79% to 11.5% among the drug resistant isolates. CONCLUSIONS: The results obtained showed that ill-defined T, Haarlem, the Turkey family (previously designated as LAM7-TUR family with high phylogeographical specifity for Turkey), Beijing and LAM were predominant lineages observed in almost 80% of the drug-Resistant M. tuberculosis complex clinical isolates in Ankara, Turkey.

Molecular diversity of drug resistant mycobacterium tuberculosis strains in Western Turkey.

OBJECTIVE: The aim of this study was to investigate the molecular diversity and clonal relationship of drug resistant Mycobacterium tuberculosis strains isolated in Western Turkey. MATERIALS AND METHODS: A total of 87 strains isolated between 2006 and 2009, eight of which were rifampicin monoresistant and 79 were multidrug resistant, were analyzed with IS6110 RFLP and spoligotyping methods. RESULTS: The results of spoligotyping showed that 7% of the strains were orphans, and 8% were undefined for family in the SpolDB4 database. Major families of the strains were LAM (38%), T (35%), Haarlem (7%), Beijing (2%), S (2%) and U (1%) families. The clustering rate by spoligotyping was calculated as 75%. The most predominant SIT cluster was SIT41 (29%). According to the results of IS6110 RFLP, 71 different patterns of IS6110 were observed. Low copy number was found in 26% of the strains. When the results of two methods were combined, the final clustering rate was calculated as 26%. CONCLUSIONS: The genotypical distribution of drug resistant tuberculosis isolates in our region indicates genetic diversity and the clustering rate was found low in our region. However, more comprehensive and long-term molecular epidemiological studies are needed to control the drug resistant strains.

Demographic and microbial characteristics of extrapulmonary tuberculosis cases diagnosed in Malatya, Turkey, 2001-2007.

BACKGROUND: Extrapulmonary tuberculosis (EPTB) has an increasing rate in Turkey. The reason remains largely unknown. A better understanding of the demographic and microbial characteristics of EPTB in the Turkish population would extend the knowledgebase of EPTB and allow us to develop better strategies to control tuberculosis (TB). METHODS: We retrospectively evaluated clinical and laboratory data of 397 bacteriologically-confirmed TB cases diagnosed during an eight year-period using by chi-square analysis and multivariate logistic regression model. RESULTS: Of the 397 study patients, 103 (25.9%) had EPTB and 294 (74.1%) had pulmonary tuberculosis (PTB). The most commonly seen two types of EPTB were genitourinary TB (27.2%) and meningeal TB (19.4%). TB in bone/joints, pleural cavity, lymph nodes, skin, and peritoneal cavity occurred at a frequency ranging from 9.7% to 10.7%. The age distribution was significantly different (P<0.01) between PTB and EPTB, with patients older than 45 years tending to have an increased risk of EPTB. Furthermore, the distribution of different types of EPTB differed significantly among age groups (P=0.03). Meningeal and bone and/or joint TB were more commonly observed among the male patients, while lymphatic, genitourinary, and peritoneal TB cases were more frequently seen among females. Unique strain infection was statistically significantly associated with EPTB (OR: 2.82, 95% CI [1.59, 5.00]) CONCLUSIONS: EPTB accounted for a significant proportion of TB cases in Malatya, Turkey between 2001 and 2007. The current study has provided an insight into the dynamics of EPTB in Malatya, Turkey. However, the risk factors for having EPTB in Malatya, Turkey remain to be assessed in future studies using population-based or randomly selected sample.

Integration of Mycobacterium tuberculosis drug susceptibility testing and genotyping with epidemiological data analysis to gain insight into the epidemiology of drug-resistant tuberculosis in Malatya, Turkey.

Drug-resistant tuberculosis (TB) presents a major challenge to global TB control. To gain a better understanding of drug-resistant TB epidemiology in Malatya, Turkey, we conducted the present study using 397 Mycobacterium tuberculosis clinical isolates collected from Malatya, Turkey, in recent years (2000-2007). Resistance to any anti-TB drug was found in 29% (114 of 397) of the study isolates, while the multidrug resistance (MDR) rate was approximately 4.5% (18 of 397). Resistances to isoniazid (15.5%) and streptomycin (13.4%) were about twice as high as resistance to rifampin (RMP) (6.3%) and ethambutol (EMB) (6.0%). Importantly, 28% (7 of 25) of the RMP-resistant isolates were non-MDR isolates, as when a significant proportion of RMP-resistant isolates in a population are non-MDR, the predictive value of molecular detection of RMP resistance for MDR can be significantly reduced. Both identical and varied drug resistance patterns were seen in the same genotyping-defined clusters, suggesting that both primary and acquired resistance have contributed to the drug-resistant TB epidemic in Malatya, Turkey. In addition, drug-resistant cases were found to be more likely to be males (odds ratio [95% confidence interval], 1.82 [1.13, 2.94]), suggesting a potential role of gender in the epidemiology of drug-resistant TB in the study population. This study demonstrates that the integration of drug susceptibility testing with genotyping and epidemiological data analysis represents a useful approach to studying the epidemiology of drug-resistant TB.

[A case of fatal disseminated infection caused by Mycobacterium bovis BCG strain and the identification of the isolate by spoligotyping]. / Mycobacterium bovis BCG susunun neden oldugu fatal disemine enfeksiyon olgusu ve izolatin spoligotiplendirme ile tanimlanmasi.

The vaccine strain Mycobacterium bovis BCG may lead to disseminated infection in patients with immune deficiency. In this report a patient who developed fatal disseminated tuberculosis caused by M. bovis BCG strain was presented. One year old male patient with the previous history of recurrent lower respiratory tract infection, was admitted to the hospital with the complaints of fever, cough and diarrhea continuing for 20 days. There was no family history of tuberculosis or history of contact with a tuberculosis case. Physical examination of the case revealed growth retardation and reticular and reticulonodular infiltration was detected in his chest X-ray. The results of sweat test, cystic fibrosis gene mutation analysis and metabolic screening tests were normal. Since fever continued and infiltrations persisted in the chest X-ray despite antibiotic therapy, PPD test was applied and acid-fast bacilli (AFB) were investigated in his gastric aspirate and stool samples for three consecutive days. PPD test was negative and no AFB were detected in the microscopic examination of the clinical samples. However, growth in Lowenstein-Jensen medium was detected in the stool sample on the 38th day of incubation. The antimycobacterial susceptibility testing performed at BACTEC MGIT (Mycobacterial Growth Indicator Tube) 960 system (Becton-Dickinson, USA) revealed that the isolate was susceptible to rifampin, isoniazid, streptomicin and ethambutol. Since the isolates did not grow at PNB (para-nitro benzoic acid) medium and niacin and nitrate activities were negative, spoligotyping (spacer oligonucleotide typing) was performed and DR loci characteristic for M. bovis BCG strain were detected. However, the patient died 2 weeks before the culture results were obtained. The effective use of mycobacteriology laboratories and cooperation between laboratory and clinics provide advantages in the early diagnosis and treatment of tuberculosis cases, decreasing the morbidity and the mortality.

Gold(I) complexes of N-heterocyclic carbene ligands containing benzimidazole: synthesis and antimicrobial activity.

Gold(I) N-heterocyclic carbene (NHC) complexes were obtained in good yields from the corresponding silver complexes by treatment with [AuCl(PPh3)] following the commonly used silver carbene transfer route. The silver complexes were synthesized from the benzimidazolium halide salts by the in situ reactions with Ag2O in dichloromethane as a solvent at room temperature. All gold complexes have been characterized by 1H-NMR, 13C-NMR and IR spectroscopy and elemental analysis. Au-NHC complexes were evaluated for their in vitro antimicrobial activity against a variety of Gram-positive and Gram-negative bacteria and fungal species.

Synthesis and antimicrobial activity of novel Ag-N-hetero-cyclic carbene complexes.

A series of imidazolidinium ligand precursors are metallated with Ag2O to give silver(I) N-heterocyclic carbene complexes. All compounds were fully characterized by elemental analyses, 1H-NMR, 13C-NMR and IR spectroscopy techniques. All compounds studied in this work were screened for their in vitro antimicrobial activities against the standard strains: Enterococcus faecalis (ATCC 29212), Staphylococcus aureus (ATCC 29213), Escherichia coli (ATCC 25922), Pseudomonas aeruginosa (ATCC 27853) and the fungi Candida albicans and Candida tropicalis. The new imidazolidin-2-ylidene silver complexes have been found to display effective antimicrobial activity against a series of bacteria and fungi.