Environmental contamination by dog’s faeces: a public health problem?

The risk to public health from the large number of dog stools present on streets of urban areas is cause for concern. Dog faeces may be a serious hazard because they may contain microorganisms that are both pathogenic to humans and resistant to several classes of antibiotics. The aim of this study was to evaluate the potential for zoonotic infections and for the presence of antibiotic resistant bacteria in canine faeces which contaminates the urban environment. A total of 418 canine faecal samples were collected from streets in seven areas of Bari, Southern Italy. We have isolated multi-drug resistant Enterococci and meticillin-resistant Staphylococcus aureus from these dog faecal samples. The presence of the resistant bacteria in an urban environment may represent a public health hazard which requires control measures by competent authorities. No Salmonella, Yersinia or Campylobacter species were isolated. Giardia cysts were detected in 1.9% of the samples. The predominant Enterococcus species were E. faecium (61.6%), E. gallinarum (23.3%) and E. casseliflavus (5.5%). Other species, including E. faecalis were also isolated. These strains were resistant to clindamycin (86.3%), tetracycline (65.7%), erythromycin (60.27%) and ampicillin (47.9%). High-level aminoglycoside resistance (HLAR) was found in 65.7% of enterococci. Resistance to three or more antibiotics and six or more antibiotics were observed in 67.12% and 38.4% of Enterococcus spp., respectively. Resistance to vancomycin and teicoplanin was not detected in any of the Enterococcus spp. isolated. Methicillin-resistant Staphylococcus aureus was isolated in 0.7% of the faecal samples. Canine faeces left on the streets may represent a risk factor for transmission of microorganisms and a reservoir of multidrug- resistant bacteria thus contributing to the spread of resistance genes into an urban area.

In vitro activity of Aloe vera inner gel against Helicobacter pylori strains

Aloe barbadensis Miller (Aloe vera) is a herbal remedy widely used for a variety of illnesses; A. vera leaf extracts have been promoted for detoxification, cure constipation, help flush out toxins and wastes from the body, promote digestion and are used in the treatment of peptic ulcer for cytoprotective action. The aim of this study was to evaluate the antibacterial activity of A. vera inner gel against both susceptible and resistant Helicobacter pylori strains isolated in Abruzzo region, Italy. The inner gel of leaves of a 5-year-old plant of A. vera was extracted, homogenized and tested from 800 to 1.56 mg ml(-1) against 14 clinical strains and one reference strain of H. pylori using the broth microdilution methodology. Furthermore, the sample of A. vera was investigated for the chemical fingerprint of anthraquinones. The inhibitory concentrations of A. vera inner gel were similar to the bactericidal ones, with values ranging from 6.25 to 800 mg ml(-1) . Fifty per cent of the detected strains, independently of their susceptibility profile, were inhibited in their growth at 100 mg ml(-1) . Aloe vera inner gel expresses antibacterial properties against H. pylori and, therefore, in combination with antibiotics, could represent a novel strategy for the treatment of the infection of H. pylori, especially in cases of multiresistance.

SIGNIFICANCE AND IMPACT OF THE STUDY

The study demonstrates that the Aloe vera inner gel expresses antibacterial properties against both susceptible and resistant Helicobacter pylori strains. These findings may impact on the antimicrobial resistance phenomenon of H. pylori, proposing the A. vera inner gel as a novel effective natural agent for combination with antibiotics for the treatment of H. pylori gastric infection.

Biofabrication of broad range antibacterial and antibiofilm silver nanoparticles

Silver nanoparticles (AgNPs) were biosynthesized via a green route using ten different plants extracts (GNP1- Caryota urens, GNP2-Pongamia glabra, GNP3- Hamelia patens, GNP4-Thevetia peruviana, GNP5-Calendula officinalis, GNP6-Tectona grandis, GNP7-Ficus petiolaris, GNP8- Ficus busking, GNP9- Juniper communis, GNP10-Bauhinia purpurea). AgNPs were tested against drug resistant microbes and their biofilms. These nanoparticles (NPs) were characterised using UV-vis spectroscopy, transmission electron microscope, Fourier transform infrared spectroscopy, X-ray diffraction and Image J software. Most of the AgNPs were distributed over a range of 1 of 60 nm size. The results indicated that AgNPs were antibacterial in nature without differentiating between resistant or susceptible strains. Moreover, the effect was more prominent on Gram negative bacteria then Gram positive bacteria and fungus. AgNPs inhibited various classes of microbes with different concentration. It was also evident from the results that the origin or nature of extract did not affect the activity of the NPs. Protein and carbohydrate leakage assays confirmed that the cells lysis is one of the main mechanisms for the killing of microbes by green AgNPs. This study suggests that the action of AgNPs on microbial cells resulted into cell lysis and DNA damage. Excellent microbial biofilm inhibition was also seen by these green AgNPs. AgNPs have proved their candidature as a potential antibacterial and antibiofilm agent against MDR microbes.

Frequency of clinically isolated strains of oral Candida species at Kagoshima University Hospital, Japan, and their susceptibility to antifungal drugs in 2006-2007 and 2012-2013

BACKGROUND

The isolation frequency and susceptibility to antifungal agents of oral Candida isolates from patients with oral candidiasis (OC) were compared between studies conducted in 2006-2007 and 2012-2013.

METHODS

A total158 strains was isolated from 112 patients who visited Kagoshima University Hospital for the treatment of OC during the 14-month period from February 2012 and March 2013, and evaluated on the isolation frequency of each Candida strain and the susceptibility against antifungal drugs as compared to those evaluated in 2006-2007.

RESULTS

There was a higher frequency of xerostomia as a chief complaint and of autoimmune disease in the 2012-2013 study than in the 2006-2007 study. More than 95% of Candida isolates were C. albicans and C. glabrata. In addition, the proportion of the latter increased from 12.3% in the 2006-2007 study to 23.4% in the 2012-2013 study, while the proportion of the former decreased from 86.2% to 72.8%, respectively. C. albicans was isolated in almost all patients, while C. glabrata was only isolated concomitantly with C. albicans. Minimal inhibitory concentrations (MICs) were not significantly different between groups with a few exceptions. Candida isolates, of which MICs surpassed break points, apparently increased for miconazole and itraconazole against C. glabrata in the 2012-2013 study, but this was not statistically significant. As a result, more cases of autoimmune disease, a greater number of C. glabrata isolates, and higher resistance to azoles were seen in the 2012-2013 study than in the 2006-2007 study.

CONCLUSION

These data indicate that with recent increases in C. glabrata infection, a causative fungus of OC, and in C. glabrata resistance to azoles, caution is needed in the selection of antifungal drugs for the treatment of OC.

Brevinin-1GHd: a novel Hylarana guentheri skin secretion-derived Brevinin-1 type peptide with antimicrobial and anticancer therapeutic potential

Host-defense antimicrobial peptides (AMPs) from amphibians are usually considered as one of the most promising next-generation antibiotics because of their excellent antimicrobial properties and low cytotoxicity. In the present study, one novel Brevinin-1 type peptide, Brevinin-1GHd, was isolated and characterized from the skin secretion of the frog, Hylarana guentheri. Brevinin-1GHd was found to possess a wide range of antimicrobial activity through penetrating the bacterial membrane within a short time while showing low hemolysis at bactericidal concentrations, even against the resistant strains. It also inhibited and eradicated biofilms that are thought to be closely related to the rise in resistance. Meanwhile, Brevinin-1GHd exhibited wide-spectrum anti-proliferation activity toward human cancer lines. Taken together, these results indicate that Brevinin-1GHd with its excellent antimicrobial and anticancer activities is a promising candidate for a novel antibiotic agent, and study of its structure–activity relationships also provided a rational template for further research and peptide analog design.

Potent Antitrypanosomal Activities of 3-Aminosteroids against African Trypanosomes: Investigation of Cellular Effects and of Cross-Resistance with Existing Drugs

Treatment of animal African trypanosomiasis (AAT) requires urgent need for safe, potent and affordable drugs and this has necessitated this study. We investigated the trypanocidal activities and mode of action of selected 3-aminosteroids against Trypanosoma brucei brucei. The in vitro activity of selected compounds of this series against T. congolense (Savannah-type, IL3000), T. b. brucei (bloodstream trypomastigote, Lister strain 427 wild-type (427WT)) and various multi-drug resistant cell lines was assessed using a resazurin-based cell viability assay. Studies on mode of antitrypanosomal activity of some selected 3-aminosteroids against Tbb 427WT were also carried out. The tested compounds mostly showed moderate-to-low in vitro activities and low selectivity to mammalian cells. Interestingly, a certain aminosteroid, holarrhetine (10, IC50 = 0.045 ± 0.03 µM), was 2 times more potent against T. congolense than the standard veterinary drug, diminazene aceturate, and 10 times more potent than the control trypanocide, pentamidine, and displayed an excellent in vitro selectivity index of 2130 over L6 myoblasts. All multi-drug resistant strains of T. b. brucei tested were not significantly cross-resistant with the purified compounds. The growth pattern of Tbb 427WT on long and limited exposure time revealed gradual but irrecoverable growth arrest at ≥ IC50 concentrations of 3-aminosteroids. Trypanocidal action was not associated with membrane permeabilization of trypanosome cells but instead with mitochondrial membrane depolarization, reduced adenosine triphosphate (ATP) levels and G₂/M cell cycle arrest which appear to be the result of mitochondrial accumulation of the aminosteroids. These findings provided insights for further development of this new and promising class of trypanocide against African trypanosomes.

Molecular characterization of serine/threonine protein phosphatase of Eimeria tenella

Avian coccidiosis is a widespread and economically significant poultry disease caused by several Eimeria species, including Eimeria tenella. Previously, E. tenella serine/threonine protein phosphatase (EtSTP) was found to be differentially expressed in drug-sensitive (DS) and drug-resistant strains using RNA-seq. In the present study, we found that transcription and translation levels of EtSTP were higher in diclazuril-resistant (DZR) strains and maduramicin-resistant (MRR) strains than in DS strains using quantitative real-time PCR (qPCR) and Western blotting. Enzyme activity results indicated that the catalytic activity of EtSTP was higher in the two drug-resistant strains than in DS strains. Western blot and qPCR analysis also showed that expression levels of EtSTP were higher in unsporulated oocysts (UO) and second-generation merozoites (SM). Indirect immunofluorescence localization showed that EtSTP was located in most areas of the parasite with the exception of refractile bodies, and fluorescence intensity was enhanced during development. In vitro inhibition experiments showed that the ability of sporozoites (SZ) to invade cells was significantly decreased after treatment with anti-rEtSTP antibody. These results indicated that EtSTP acted mainly during the developmental and reproductive stages of the parasite and may be related to the resistance of coccidia to external drug pressure.

Microbial contamination of multiple-use bottles of fluorescein ophthalmic solution

BACKGROUND

The contamination of ophthalmic solutions in ophthalmic practices remains an important cause of a myriad of secondary eye infections and a source of aggravation of ocular disorders such as corneal ulcers and keratitis. The aim of this study was to investigate the possible microbial contamination of fluorescein sodium dye solutions used in eye clinics in Ghana.

METHODS

Fluorescein sodium solutions were collected from various eye clinics in Ghana. Twenty-one samples of multiple-use fluorescein ophthalmic solutions were collected from various regions in Ghana. Eighteen unopened bottles yet to be used were also collected to serve as controls from the same facilities. The solutions were inoculated in different culture plates (blood agar, MacConkey agar, Sabouraud dextrose agar and plate count agar). The resulting microbial growth was identified using standard microbial identification techniques. Susceptibility tests were performed to ascertain the clinical importance of the organisms identified.

RESULTS

Positive cultures were recorded for all 21 multiple-use bottles (in-use) collected, but there were no positive cultures for the unopened bottles (yet to be used). Six different genera of bacteria were identified from fluorescein solutions, including resistant strains of Staphylococci spp., Bacillus spp., Klebsiella spp., Pseudomonas spp., Haemophilus spp. and Bordetella spp. Pseudomonas spp. were the most common bacterial contaminants. For fungi contaminations, Aspergillus spp., Penicillium spp. and Cladosporium spp. were isolated. The most common fungal contaminants were Aspergillus spp.

CONCLUSIONS

Multiple-use bottles of fluorescein solution used in eye clinics in Ghana were contaminated with clinically important strains of bacteria and fungi.

Pandrug-resistant Acinetobacter Baumannii Infection Identified in a Non-intensive Care Unit Patient: A Case Study

Acinetobacter baumannii is a major cause of hospital-acquired infections, particularly in patients treated in intensive care units (ICUs). It can be a causal agent of conditions like pneumonia, bacteremia, meningitis, soft-tissue, and urinary tract infections, and is associated with high mortality rates. We present a case of a 72-year-old male patient treated for fractured neck of femur who went on to develop an infection from a pandrug-resistant Acinetobacter baumannii isolated in blood and urine cultures during his hospitalization in trauma and orthopedic ward. The patient was operated on the second day following his injury with a cephalomedullary nail device and became febrile with rigors on day six. His clinical condition deteriorated over the next days and his inflammatory markers reached a peak value on day 10 post-injury. Acinetobacter baumannii was isolated from blood and urine cultures and a regimen combining rifampicin, tigecycline, and vancomycin in their maximum doses was initiated. The patient was discharged on day 26 post-injury. Before discharge, he had received the above-mentioned intravenous antibiotic regimen for 14 days. He had also been afebrile for six days and undergone three consecutive negative blood culture samples.

Characterisation of the in vitro activity of a Nitazoxanide-N-methyl-1H-benzimidazole hybrid molecule against albendazole and nitazoxanide susceptible and resistant strains of Giardia intestinalis and its in vivo giardicidal activity

BACKGROUND

It was previously demonstrated that CMC-20, a nitazoxanide and N-methyl-1H-benzimidazole hybrid molecule, had higher in vitro activity against Giardia intestinalis WB strain than metronidazole and albendazole and similar to nitazoxanide.

OBJETIVES

To evaluate the in vitro activity of CMC-20 against G. intestinalis strains with different susceptibility/resistance to albendazole and nitazoxanide and evaluate its effect on the distribution of parasite cytoskeletal proteins and its in vivo giardicidal activity.

METHODS

CMC-20 activity was tested against two isolates from patients with chronic and acute giardiasis, an experimentally induced albendazole resistant strain and a nitazoxanide resistant clinical isolate. CMC-20 effect on the distribution of parasite cytoskeletal proteins was analysed by indirect immunofluorescence and its activity was evaluated in a murine model of giardiasis.

FINDINGS CMC-20

showed broad activity against susceptible and resistant strains to albendazole and nitaxozanide. It affected the parasite microtubule reservoir and triggered the parasite encystation. In this process, alpha-7.2 giardin co-localised with CWP-1 protein. CMC-20 reduced the infection time and cyst load in feces of G. muris infected mice similar to albendazole.

MAIN CONCLUSIONS

The in vitro and in vivo giardicidal activity of CMC-20 suggests its potential use in the treatment of giardiasis.

Antibacterial, anti‐inflammatory and antioxidant effects of acetyl‐11‐α‐keto‐β‐boswellic acid mediated silver nanoparticles in experimental murine mastitis

Mastitis is an important economic disease causing production losses in dairy industry. Antibiotics are becoming ineffective in controlling mastitis due to the emergence of resistant strains requiring the development of novel therapeutic agents. In this study, the authors present the phytochemical synthesis of silver nanoparticles (AgNPs) with acetyl‐11‐α‐keto‐β‐boswellic acid and evaluation of their activity in Staphylococcus aureus induced murine mastitis. Boswellic acid mediated AgNP (BANS) were oval, polydispersed (99.8 nm) with an minimum inhibitory concentration of 0.033 µg ml−1 against S. aureus , inhibitory concentration (IC50) of 30.04 µg ml−1 on mouse splenocytes and safe at an in vivo acute oral dose of 3.5 mg kg−1 in mice. Mastitis was induced in lactating mice by inoculating S. aureus (log10 5.60 cfu) and treated 6 h post‐inoculation with BANS (0.12 mg kg−1, intramammary and intraperitoneal), and cefepime (1 mg kg−1, intraperitoneal). S. aureus inoculated mice showed increased bacterial load, neutrophil infiltration in mammary glands and elevated C‐reactive protein (CRP) in serum. Oxidative stress was also observed with elevated malondialdehyde level, superoxide dismutase (SOD) and catalase (CAT) activities. BANS treatment significantly (P  < 0.05) reduced bacterial load, CRP, SOD, CAT activities and neutrophil infiltration in affected mammary glands. BANS could be a potential therapeutic agent for managing bovine mastitis.

Antibiotic-resistant bacteria in bovine milk in India

Antibiotic resistance (ABR) is a global issue that draws the attention of all healthcare experts in the veterinary and medical fields. Of various factors, indiscriminate and unregulated antibiotic usage in the animals reared for food production, especially in cows and buffaloes suffering from mastitis, contribute significantly to the rising incidence of resistant bacteria. A literature survey reveals the spread of resistant strains of mastitis-causing bacteria, like Staphylococcus aureus and Escherichia coli, to humans. In addition, antibiotic residues detected in milk samples against all major groups of antibiotics are likely to enter the human body through the food chain and aggravate the condition. The cumulative effects of ABR have emerged as a silent killer. The benefits of systematic surveillance on ABR in India are yet to be available. Here is an attempt to understand the ABR burden in India associated with bovine milk and its mitigation strategies.

[Conjunctival microflora and its antibiotic sensitivity after serial intravitreal injections]

INTRODUCTION

The approach to post-procedure management of patients undergoing intravitreal injections should be unified and consistent. Frequent use of antibiotic drugs leads to generation of resistant conjunctival strains.

PURPOSE

To study the composition of conjunctival microflora and its antibiotic susceptibility in patients who received 20 or more intravitreal injections and concomitant antibiotic therapy, and in a group of patients of the same age without history of intravitreal injections or ophthalmological operations.

MATERIAL AND METHODS

A total of 40 inoculations were performed (20 patients in each group, 40 eyes). In case of culture growth, species identification and antibiotic sensitivity of the microorganisms were investigated using automated identification and susceptibility testing system BD Phoenix 100.

RESULTS

Culture growth was observed in 70% of the control group patients. All isolated microorganisms were different types of staphylococci - Staphylococcus epidermidis (78.57%), S. caprae (7.14%), S. hominis (7.14%), and S. aureus (7.14%). In the second group, we observed culture growth in 55% of cases. Eleven cultures were Gram-positive bacteria: S. epidermidis (72.73%), S. haemolyticus (18.18%), S. aureus (9.09%). Gram-negative Pseudomonas aeruginosa was detected in 1 patient. In the control group, multi-resistant cultures accounted for 42.86%. In the group of patients with multiple intravitreal injections, 75% of cases showed multiresistance (9 out of 12 isolates). In the group of patients who have undergone 20 or more injections, greatest resistance was observed to penicillin G, doxycycline, gentamicin, erythromycin, clindamycin, moxifloxacin, fusidic acid, chloramphenicol, and trimethoprim/sulfamethoxazole compared to the control group.

CONCLUSION

Overuse of antibiotics in the management of patients receiving intravitreal injections leads to selection of resistant strains.

[Opportunistic fungal infections of ent organs. Part 2]

The review of literature summarized information about main fungal pathogens and theirs proportions in infections affecting the ENT areas. Different nosological forms of fungal diseases of upper respiratory tract and ear were considered, and listed the main clinical manifestations. Microbiological diagnosis of mycoses affecting the ENT organs is based on microscopic, mycological, immunological and molecular-genetic studies. The review paid particular attention to the treatment of fungal infections of the areas. It presented the classification of modern antifungal drugs, and described regimens and duration of treatment depending on fungus type, disease severity and other patient's condition. It was noted that success of therapy of fungal infections affecting upper respiratory tract and ear now provided by using of complex antimycotics, immunotropic agents, antihistamines and probiotics. The emergence of resistant strains of micromycetes was observed as the main reason for decreased effectiveness of antifungal agents. Prospective solution of this problem were indicated by way of using of biologically active plant compounds, nanoantiseptics, metal ions, enzymes and photodynamic therapy. The review suggested relevance of increasing rates of fungal morbidity affecting the ENT areas, the necessity of early diagnosis, the search of new antifungal agents and compounds with fungicidal activity and theirs introduction into clinical practice.

Antimicrobial Activity of Catechol-Containing Biopolymer Poly[3-(3,4-dihydroxyphenyl)glyceric Acid] from Different Medicinal Plants of Boraginaceae Family

This study reports the antimicrobial activities of the biopolymers poly[3-(3,4-dihydoxyphenyl)glyceric acid] (PDHPGA) and poly[2-methoxycarbonyl-3-(3,4-dihydroxyphenyl)oxirane] (PMDHPO), extracted from the six plants of Boraginaceae family: Symphytum asperum (SA), S. caucasicum (SC), S. gr and iflorum (SG), Anchusa italica (AI), Cynoglosum officinale (CO), and Borago officinalis (BO) collected in various parts of Georgia. The study revealed that the antibacterial activities were moderate, and biopolymers from only three plants showed activities against all tested bacteria. Biopolymers from CO stems as well as SC and AI did not show any activity except low activity against a resistant P. aeruginosa strain, which was the most resistant among all three resistant strains. On the other hand, the antifungal activity was better compared to the antibacterial activity. Biopolymers from BO stems exhibited the best activities with MIC/MFC at 0.37-1.00 mg/mL and 0.75-1.5 mg/L, respectively, followed by those from SG stems. Biopolymers from SC and AI roots showed antifungal activities against all six fungi, in contrast to the antibacterial activity, while biopolymers from CO stems and SA roots had activities against four fungi and one fungus, respectively. The sugar-based catechol-containing biopolymers from BO stems demonstrated the best activities among all tested biopolymers against T. viride, P. funiculosum, P. cyclpoium var verucosum, and C. albicans (MIC 0.37 mg/mL). In addition, biopolymers from SG stems were half as active against A. fumigatus and T. viride as ketoconazole. Biopolymers from all plant materials except for CO stems showed higher potency than ketoconazole against T. viride. For the first time, it was shown that all plant materials exhibited better activity against C. albicans, one of the most dreadful fungal species.

The role of alert pathogens in bacterial diseases in patients hospitalized at the Department of Pulmonary Diseases and Tuberculosis Public Clinical Hospital No 3 in Zabrze in 2008-2012

BACKGROUND

The current public health problem is the increasing bacterial resistance to antibiotics. Microorganisms isolated from infections are more often non-susceptible to most available drugs. The microorganisms producing resistance mechanisms have been classified as so called alert pathogens.

METHODS

We performed a total number of 3810 tests of bronchoalveolar lavage and sputum of patients hospitalized for respiratory diseases at the Department of Pulmonary Diseases and Tuberculosis at Public Clinical Hospital No 3 in Zabrze (Poland). The research was performed in the microbiological laboratory of the Department of Microbiology and Immunology in Zabrze, Medical University of Silesia in Katowice, Poland. The analysis included Gram-positive and Gram-negative alert species strains.

RESULTS

In the period of five years, 144 strains of alert microorganisms have been isolated. The percentage of Gramnegative alert pathogens producing ESBL and KPC increased. MRSA, Steptococcus pneumoniae and Streptococcus pyogenes have been found to be the most often present among Gram-positive alert microorganisms. The lowest value of cultured alert pathogens (3.9%) was noted in 2008, whereas the highest (16.5%) in 2011. Gram-positive alert microorganisms showed resistance to macrolides and lincosamides, however, Gram-negative alert microorganisms showed the highest percentage of resistance to penicillins, penicillins with inhibitors and cephalosporins.

CONCLUSIONS

Our work has shown that over the period 2008–2012 an increased percentage of Gramnegative and Gram-positive alert microorganisms was observed.

[Antibiotic resistance in patients after serial intravitreal injections]

Despite the lack of convincing data on the effectiveness of antibiotic therapy in the prevention of Post-Injection Endophthalmitis (PIE), the use of topical antibiotics for intravitreal injections is still a common practice. Frequent, monthly use of antibiotics results in changes of the composition of conjunctival flora and spontaneous mutations of bacteria, and leads to selective survival of resistant and virulent strains that can cause serious damage inside the eye.

Rutin/Sulfobutylether-β-Cyclodextrin as a Promising Therapeutic Formulation for Ocular Infection

Ocular pathologies present significant challenges to achieving effective therapeutic results due to various anatomical and physiological barriers. Natural products such as flavonoids, alone or in association with allopathic drugs, present many therapeutic actions including anticancer, anti-inflammatory, and antibacterial action. However, their clinical employment is challenging for scientists due to their low water solubility. In this study, we designed a liquid formulation based on rutin/sulfobutylether-β-cyclodextrin (RTN/SBE-β-CD) inclusion complex for treating ocular infections. The correct stoichiometry and the accurate binding constant were determined by employing SupraFit software (2.5.120) in the UV-vis titration experiment. A deep physical-chemical characterization of the RTN/SBE-β-CD inclusion complex was also performed; it confirmed the predominant formation of a stable complex (Kc, 9660 M-1) in a 1:1 molar ratio, with high water solubility that was 20 times (2.5 mg/mL) higher than the free molecule (0.125 mg/mL), permitting the dissolution of the solid complex within 30 min. NMR studies revealed the involvement of the bicyclic flavonoid moiety in the complexation, which was also confirmed by molecular modeling studies. In vitro, the antibacterial and antibiofilm activity of the formulation was assayed against Staphylococcus aureus and Pseudomonas aeruginosa strains. The results demonstrated a significant activity of the formulation than that of the free molecules.

Biocompatible carbon quantum dots as versatile imaging nanotrackers of fungal pathogen - Candida albicans

Aim: The development of carbon quantum dots (C-QDs) as nanotrackers to understand drug-pathogen interactions, virulence and multidrug resistance. Methods: Microwave synthesis of C-QDs was performed using citric acid and polyethylene glycol. Further, in vitro toxicity was evaluated and imaging applications were demonstrated in Candida albicans isolates. Results: Well-dispersed, ultra small C-QDs exhibited no cyto/microbial/reactive oxygen species-mediated toxicity and internalized effectively in Candida yeast and hyphal cells. C-QDs were employed for confocal imaging of drug-sensitive and -resistant cells, and a study of the yeast-to-hyphal transition using atomic force microscopy in Candida was conducted for the first time. Conclusion: These biocompatible C-QDs have promising potential as next-generation nanotrackers for in vitro and in vivo targeted cellular and live imaging, after functionalization with biomolecules and drugs.