Sabouraud Agar Plates Research Articles

Comparison of the Antimicrobial Efficacy of Conventional Versus Chitosan Re-inforced Heat-Polymerized Polymethylmethacrylate Dental Material: An In Vitro Study.

Polymethylmethacrylate (PMMA) is widely used in the fabrication of dentures due to its aesthetic appeal and mechanical strength. However, PMMA's susceptibility to microbial colonization often leads to oral infections such as denture stomatitis. Enhancing the antimicrobial properties of denture materials is crucial for improving patient outcomes.Chitosan, a natural biopolymer, possesses inherent antimicrobial properties and could potentially enhance the microbial resistance of PMMA. This study has investigated thepotential of chitosan-reinforced heat-polymerized PMMA denture material to reduce microbial colonization. The aim of the study was to evaluate and assess the anti-bacterial and antifungal properties of chitosan-reinforced heat-polymerized PMMA with conventional heat-polymerized PMMA Materials and methods:Chitosan-reinforced PMMA samples were fabricated with varying chitosan concentrations (0% control, 5%, 10%, and 15% by weight). The fabrication involved mixing chitosan powder with PMMA powder, adding monomer liquid, followed by mixing, packing, and curing using the conventional heat polymerization technique. The antimicrobial efficacy was assessed in vitro using two common oral pathogens: Streptococcus mutans and Candida albicans. Blood agar plates were used for S. mutans and Sabouraud agar plates were used for C. albicans. Each sample was placed on the respective agar plates inoculated with a standardized microbial suspension and incubated at 37°C for 24 hours. The number of colony-forming units (CFUs) was counted to quantify microbial growth. Statistical analyses, including linear regression analysis, one-way ANOVA test, and Pearson correlation were performed to evaluate the relationship between chitosan concentration and antimicrobial efficacy. The p-value was calculated to determine the statistical significance of the results. The chitosan-reinforced PMMA samples showed significantly greater antimicrobial efficacy compared to the conventional PMMA samples. The CFU counts for both S. mutans and C. albicans decreased with increasing chitosan concentration. Linear regression analysis indicated a strong negative correlation between chitosan concentration and CFU counts, with Pearson correlation coefficients of -0.97 for S. mutans and -0.98 for C. albicans. ANOVA analysis revealed a statistically significant difference in antimicrobial efficacy across different chitosan concentrations (p < 0.001). Incorporating chitosan into heat-polymerized PMMA significantly enhances its antimicrobial properties against S. mutans and C. albicans. The antimicrobial efficacy improves with higher concentrations of chitosan, with the 15% chitosan-reinforced samples showing the most substantial reduction in microbial growth. These results suggest that chitosan-reinforced PMMA dentures could be a superior alternative to conventional PMMA dentures, potentially reducing denture-related infections and improving oral health outcomes for denture wearers.

Antifungal susceptibility of Aspergillusgenus determined by the Etest® method: eleven years of experience at the Instituto Médico La Floresta. Caracas, Venezuela.

Abstract. This research aimed to determine the susceptibility of Aspergil-lus spp. to four antifungal agents using the Etest® method in several clinical samples (respiratory samples, soft tissue, otic tissue, and ocular tissue, among others) from a private health center in Venezuela. Thirty-three strains were evaluated: 11 Aspergillus section Flavi, eight Aspergillus section Fumigati, six Aspergillus section Nigri, four Aspergillus section Terrei, and four Aspergillus spp. A 0.5 McFarland standard suspension of a 5-day culture of each Aspergillusstrain was prepared on Potato Dextrose agar and then inoculated on Sabouraud agar plates with 2% glucose. Voriconazole (VCZ), amphotericin B (AMB), caspo-fungin (CAS), and posaconazole (PCZ) were tested. Minimal inhibitory concen-trations (MIC) in μg/mL were determined after 24 and 48 hours of incubation at 35 °C and th range (R), geometric mean (GM), MIC50, and MIC90 were calcu-lated. The results for the 33 Aspergillus spp. tested after 24 h were the follow-ing: VCZ (R = 0.031- 16; GM = 0.145; MIC50 = 0.125 and MIC90 = 0.5), AMB (R = 0.031-16; GM = 0.644; MIC50 = 0.5 and MIC90 = 8), CAS (R = 0.031-16; GM = 0.1076; MIC50 = 0.063 and MIC90 = 1), PCZ (R =0.031 - 0.5; GM = 0.0755; MIC50 = 0.063 and MIC90 = 0.25). This investigation allowed assessing the an-tifungal susceptibility profiles of Aspergillus spp. isolated from clinical samples by the Etest® method, which is practical, reproducible and easy to perform in microbiology laboratories.

Conjunctivitis in unusual populations: A review of rare cases and challenges in diagnosis and management

Conjunctivitis is defined as any inflammatory condition of the membrane that borders the eyelids and covers the exposed sclera. It is the most frequent reason for "red eye." The word "conjunctivitis" refers to a wide range of illnesses that manifest as conjunctival inflammation. Hyper acute, acute, or chronic inflammations are all possible, and their causes might be infectious or noninfectious. Conjunctival injection, sometimes known as "red eye," is a common presentation for various ocular illnesses and can represent up to 1% of all visits to the primary care physician. The presence of these two symptoms may identify 59% of instances with "serious eye conditions," including anterior uveitis and keratitis. Anisocoria and moderate photophobia were substantially related with "serious eye conditions. Before beginning antibiotic therapy, it is preferable to collect swabs from the discharge. The swabs are then cultured in the lab by placing them in different growth media. It is recommended to use Sabouraud agar plates to detect fungus in immunocompromised individuals and those with persistent blepharitis. Additionally, anaerobic culture plates may be beneficial, particularly for individuals who have a history of prior surgery or trauma. A very contagious kind of viral conjunctivitis is acute hemorrhagic conjunctivitis (AHC). It presents with a feeling of a foreign body, excessive weeping, and edema of the eyelids, dilated conjunctival vessels, chemosis, and subconjunctival hemorrhage. When a person is sexually active as an adult or a newborn, Neisseria gonorrhoeae is frequently the cause of hyperacute conjunctivitis. Conjunctiva, eyelids, and cornea can all be impacted by ocular allergies along with other ocular surface areas. Ocular allergy disorders have been divided into three main categories by Leonardi et al based on the immunological mechanism responsible for the final clinical appearance. Patients suffering with viral conjunctivitis have quick onset foreign body feeling, red eyes, irritation, light sensitivity, burning, and watery discharge. Patients with bacterial conjunctivitis have all of the aforementioned symptoms as well as mucopurulent discharge and mattering of the eyelids upon awakening. For individuals with conjunctivitis, general supportive therapies include allergen avoidance (pollens, animals, and dust mites), the use of artificial tears, proper hand hygiene, cold compresses, avoidance of eye rubbing, and mild cleanser to remove any allergens or debris.

Epidemiology, risk factors and antimicrobial profile of Vulvovaginal Candidiasis (VVC): A study among women in the central region of Saudi Arabia

BackgroundCandida spp. is a fungal resident of the normal microbiota of gastrointestinal tract, reproductive mucosa and oral cavity. Hence, a majority of the healthy population may be prone to the most common fungal infection such as candidiasis that can be caused by any species of Candida. In women, vaginitis or vulvovaginal candidiasis (VVC) forms a significant part of urogenital infections with a high recurrence rate thus posing a public health issue worldwide. ObjectivesThe aim of this study was to determine the prevalence of VVC, its possible risk factors and the antifungal susceptibility of the species isolated from women attending a hospital in the central region of Saudi Arabia. MethodsSamples of high vaginal swabs (HVS) were obtained from 208 women aged 15–64 years with signs and symptoms of VVC. The samples were cultured on Sabouraud agar plates (SDA) and incubated at 30°C for 10 days. Candida spp. were initially identified using morphologic characteristics, wet mount, germ tube test and finally confirmed with Vitek 2. ResultsAmong the samples, 34% were culture positive. Out of the positive samples, 68% were Candida albicans, followed by C. tropicalis (27%) and C. glabrata (2.7%). Majority of the C. albicans (16%) were observed in women between ages of 21–30 years. All the isolates were sensitive to the antifungals tested. Also, the presence of Candida spp. did not correlate to risk factors such as pregnancy, diabetes and use of antibiotics. ConclusionsPrevalence of vulvovaginal candidiasis was observed in the central region of Saudi Arabia with the predominant organism as Candida albicans.

Assessment of Antibacterial and Antifungal Properties of Root-End Filling Materials

Aim: This study aimed to assess the antimicrobial activity of MTA repair (Angelus®), Biodentine (Septodont®), and IRM(Densply®) in microorganisms isolated from the persistent periapical lesion. Materials and Methods: The microorganisms isolated were tested by Minimum Inhibitory Concentration (MIC): 50 µl of saline solution and 100 µl of MTA repair, Biodentine and IRM were used to perform the following dilutions of 1: 2, 1: 4, 1: 8, 1:16, 1:32, 1:64, 1: 128, 1: 256, 1: 512, 1: 1024. After the inoculation of the microorganisms. The culture of S. mitis was carried out on Müeller Hinton agar plates with sheep blood and for C. albicans, sabouraud agar plates, and Chromogenic candida agar Then, incubated at 37 °C for 24 h. To assess their growth Results: For C. albicans MTA repair demonstrated growth at 1:64 dilution, Biodentine: 1: 512 dilution, and IRM: 1: 1024 dilution. For S. mitis Biodentine, MTA repair and IRM demonstrated growth at: 1: 1024 dilution. Conclusion: MTA repair (Angelus) Biodentine (Septodont) and IRM were effective inhibiting C. albicans and S. mitis at their original concentrations, however, IRM and Biodentine had a greater antifungal effect than MTA when subjected to higher dilutions.

Prevalence of Candida albicans among Female Patients in Two Selected Hospitals in Owerri Metropolis, Imo State Southeastern Nigeria

The incidence of candidiasis in the female reproductive tract is a serious threat to public health. This study assesses the prevalence of Candida albicans among female patients in the two selected hospitals in Owerri metropolis. A systematic random sampling technique was used to select 120 female patients between the ages of 16-56 years. Only patients who showed no symptoms of urinary tract infections and who were not on anti-fungal therapy at the time of the study were included in the study. A well-structured interview questionnaire was used to source information on socio-demographic characteristics of the respondents as well as the risk factors of Candida albicans infections. High Vaginal Swab (HVS) was aseptically collected from each of the patients, using a sterile swab stick. The collected samples were labeled appropriately and immediately sent to the microbiology/mycology lab for analysis. The HVS samples were respectively streaked directly into sabouraud agar plates and incubated anaerobically at 37oC for 48 hours. Yeast growth characteristics were noted. Positive colonies were sub-cultured in Macconkey agar to obtain pure isolates. The Candida albicans were properly identified and confirmed by germ tube test, gram staining and biochemical tests. The results showed that the overall prevalence of Candida albicans among the women was (53.34%). The prevalence was highest among the patients in the age group 16-25 (44.17%), lower education qualification (n=65, 54.17%) and pregnant women (n=44, 36.67%). The possible risk factors for the infection include use of antibiotics (n=85, 70.83%), use of nylon underwear (n=78, 65.00), use of public toilet (n=90, 75.00%), use of squat WC (n=59, 9.17%) and use of oral contraceptive (n=59, 49.17%). The results call for preventive measures to protect women. Therefore public health education and campaign should be adopted.

Evaluación de las partículas en suspensión atmosférica y bioaerosoles fúngicos en parques urbanos de la ciudad de Santo Domingo, República Dominicana

Este estudio determinó el nivel de partículas en suspensión con diámetros ≤10 µm e ≤ 2,5 µm, y oportunistas fúngicos asociados en los parques urbanos de Mirador Sur, Iberoamericano y Colón, de la ciudad de Santo Domingo en la República Dominicana. Para esto se realizaron dos muestreos con intervalo de 24 horas, utilizando un muestreador PCE-MPC 10 para cuantificar el particulado y un Kestrel 5500 para variables atmosféricas. Las esporas fueron colectadas mediante la técnica de sedimentación en placa con agar Sabouraud e identificadas utilizando un microscopio Olimpus CX33. Según los resultados en ambos muestreos, el nivel del particulado de rango PM 2.5 µm y 10 µm en los parques no supera el límite presente en el Reglamento Técnico Ambiental de Calidad del Aire del Ministerio de Medio Ambiente y Recursos Naturales de la República Dominicana. Entre los hongos identificados se encuentran: Alternaria alternata, Aspergillus sp. 1, Aspergillus niger, Cladosporium, Dreschlera, Penicillium sp. 1, P. sp. 2, Paecilomyces sp., Nattrasia sp., Fusarium sp., Rhizophus sp., y Ulocladium sp.

Fungal contamination of ward furnishings and medical equipment used in the treatment and nursing of newborns.

Newborn babies staying on hospital wards are likely to be colonized by microorganisms, including potentially pathogenic fungi. The aim of the study was to assess the mycological purity of hospital wards and medical equipment utilized in the treatment and nursing of newborns. The study was conducted in Neonatal High Dependency Units (NHDU) and Neonatal Intensive Care Units (NICU). 539 samples were collected from 24 different sources, 130 from ward furnishings and 289 from medical equipment. The study was carried out following the microbiology research methods for sample collection. Subsequently, the samples (swabs, water from incubators, washings from respirator tubes and nasal cannulas (nCPAP)) were cultivated on Sabouraud agar plates. The stamps were collected with the application of Count-Tact method. The samples were incubated at the temperature of 25+/-2 o C and the number of fungi assessed (cfu/cm -2 of the surface area). The species were identified based on their morphological and biochemical features. Fungal growth was observed on 60% of samples collected from ward furnishings and 7% of samples collected from medical equipment. The average number of cfu/cm -2 ranged between 0-8.84 in the case of ward furnishings and between 0-1.22 cfu/cm -2 in the case of medical equipment. In 180 samples collected from the material which had direct contact with newborns no fungal growth was observed. The furnishings of the wards on which newborns were treated and nursed were contaminated with fungi to an extent which did not pose a threat to the life and health of the newborns. Medical equipment (respirators, incubators, nCPAP cannulas and masks) which came into direct contact with newborns was free from fungi.

Mitigation of microbial contamination from waste water and aerosolization by sink design

Healthcare-associated infections (HAIs) are a significant cause of increased medical costs, morbidity, mortality, and have been partly associated with sinks, their waste water outlets and associated pipework. To determine whether an engineered sink could limit microbial aerosol contaminants in the air and sink basin. Multiple comparisons were undertaken between an experimental sink, designed to limit aerosolization and p-trap contamination to a control hospital sink, both connected to a common drain system. The experimental sink was equipped with ultraviolet light (UV), an aerosol containment hood, ozonated water generator and a flush system to limit bacterial growth/aerosolization and limit microbial growth in the p-trap. Nutrient material was added daily to simulate typical material discarded into a hospital sink. Surface collection swabs, settle plates and p-trap contamination levels were assessed for bacteria and fungi. The experimental sink had significantly decreased levels of bacterial and fungal p-trap contamination (99.9% for Tryptic Soy (TSA) and Sabouraud agar (SAB) plates) relative to the initial levels. Aerosol-induced contaminant from the p-traps was significantly lower for the experimental vs the control sink for TSA (76%) and SAB (86%) agar settle plates. Limiting microbial contamination is critical for the control of nosocomial infections of in-room sinks, which provide a major source of contamination. Our experimental sink studies document that regular ozonated water rinsing of the sink surface, decontamination of p-trap water, and UV decontamination of surfaces limits microbial aerosolization and surface contamination, with potential to decrease patient exposure and reduce hospital acquired infections.

IN VITRO ANTIFUNGAL ACTIVITY OF TIMOL AND CARVACROL ON CANDIDA SPECIES

Aim: to evaluate the in vitro action of thymol and carvacrol against the yeasts of Candida albicans ATCC10231 and Candida krusei ATCC34135. Method: A laboratory study was performed to evaluate antifungal activity. The characterization of the Minimal Inhibitory Concentration (MIC) of the thymol essential oil was carried out using the technique where the microdilution is performed, in which a plate containing 96 wells is used. The determination of the Minimum Fungicidal Concentration (MFC) was performed by dripping 10 μL of each of the concentrations evaluated on Sabouraud agar plates. Results: The MIC of thymol and carvacrol for C. albicans was 40 μg/mL and for Candida krusei it did not present antifungal activity. While the MIC of nystatin was 0.03mg for both species with thymol and carvacrol. Conclusion: Thymol presented satisfactory antifungal activity against the pathogens studied, but carvacrol did not present antifungal activity.

Safety for future patients: Environmental microbiological control in an assisted fertilization institute

Background: Between 2004 and 2010 we studied the environmental areas in an assisted reproduction institute. Aspergillus spp was frequent and persistent in humidified incubators (HI) used in the initial stages of post-fertilization incubation. Strict control measures were implemented but the problems appeared again. Objective. To study with more techniques the environmental contamination where the assisted fertilization is realized Methods & Materials: Between September 2015 and September 2017, 431 samples were studied, distributed monthly by means of surface swabs and impact techniques. Swabs moistened in physiological solution were used for the study of certain surface areas. For the impact technique Sabouraud Agar (SA) and blood agar (TBA) plates were used, which were left open for 4 to 6 hours in critical environments and inside the HI. The material of each swab was eluted in 1 ml of physiological solution and all suspensions were conveniently shaken; 200 ul of each sample were taken and inoculated into tryptein-broth, SA and Cystine-Lactose-Depleted Electrolytes (CLDE) for quantitative studies. Simultaneously, we evaluated biofilm formation (BF) in critical areas. Bacteria, yeasts and fungi were studied by conventional techniques. Results: Bacteria recovered significantly in 293/431 samples (67.9%) and highly virulent microorganisms (Staphylcoccus aureus and Pseudomonas aeruginosa) were isolated in the environmental areas (operating rooms and washing area). The central problem is the contamination of HI where fungi are the main colonizers. Aspergillus species were the most relevant and were isolated in 125/431 (29.0%) studies; other filamentous fungi (Paecilomyces variotti, Mucor spp., Penicillium spp., Curvularia spp., Ulocladium sp., Alternaria sp.) were recovered in 107/431 (24.8%) and in 50/431 (11.6%) yeasts (no albicans Candida, C. albicans and Rhodotorula mucilaginosa). BF formation was detected in 45 cases corresponding to critical areas. Conclusion: Continuous cleaning of HI is essential to avoid failure of embryo evolution. The presence of BF can explain the fungal permanence since they make difficult the access to almost all the elements destined to the disinfection. Microbiological control of surfaces and indoor air allows the identification, assessment and prevention of contamination risks in sterile and non-sterile critical areas, thus safeguarding maternal and future patient safety

Resistance to Echinocandins in Candida Can Be Detected by Performing the Etest Directly on Blood Culture Samples.

We examined the rapid evaluation of susceptibility to echinocandins in Candida spp. using the Etest performed directly on positive blood cultures and anidulafungin-containing agar plates. We prospectively collected 80 positive blood cultures (Bactec-FX system, Becton-Dickinson, Cockeysville, MD, USA) with echinocandin-susceptible Candida spp. (n = 60) and echinocandin-intermediate Candida parapsilosis (n = 20) from patients with candidemia. Additionally, blood culture bottles of nonfungemic/bacteremic patients were spiked with 35 echinocandin-resistant Candida species isolates. A total of 2 to 4 drops of medium from each bottle were stroked directly onto both RPMI 1640 agar plates with micafungin and anidulafungin Etest strips (ETDIR) and Sabouraud agar plates containing 2 mg/liter of anidulafungin. The isolates were tested according to the EUCAST method and Etest standard (ETSD). Essential and categorical agreement between the methods was calculated. The essential agreement and categorical agreement between the EUCAST method and ETDIR and ETSD were both >97.4%. The essential agreement between ETDIR and the EUCAST method for both echinocandins was >97%. The categorical agreement between the FKS sequence and ETDIR was 97.4%. The ETDIR MICs of anidulafungin and micafungin (≥0.19 mg/liter and ≥0.064 mg/liter, respectively) effectively separated all susceptible FKS wild-type isolates from the resistant FKS mutant isolates. The categorical agreement (62.6%) between the EUCAST method and growth on anidulafungin-containing plates was poor, with the best agreement observed for Candida glabrata (94.2%). When performed directly on positive blood cultures from patients with candidemia, the Etest with micafungin and anidulafungin is a reliable procedure for the rapid testing of susceptibility to echinocandins in Candida species isolates.

Mutant Prevention Concentration and Mutant Selection Window of Micafungin and Anidulafungin in Clinical Candida glabrata Isolates.

We report the mutant prevention concentration (MPC) and mutant selection window (MSW) for micafungin and anidulafungin administered to treat Candida glabrata We also determine the mutation frequency. We studied 20 echinocandin-susceptible, fluconazole-intermediate, and FKS wild-type C. glabrata isolates. Adjusted inocula were stroked directly onto Sabouraud agar plates containing different concentrations of micafungin or anidulafungin and visually inspected daily for up to 5 days of incubation. Individual colonies growing on the plates containing echinocandins at 1 mg/liter were selected for antifungal susceptibility testing. The FKS genes of the resulting individual phenotypically resistant colonies were sequenced, and the MPC, MSW, and mutation frequency were determined. Biofilm was quantified, and the growth kinetics and virulence (Galleria mellonella model) of the resulting individual FKS mutant colonies were studied. For micafungin and anidulafungin, we found similar results for the MPC (0.06 to 2 mg/liter and 0.25 to 2 mg/liter, respectively), MSW (0.015 to 2 mg/liter for both echinocandins), and mutation frequency (3.7 × 10-8 and 2.8 × 10-8, respectively). A total of 12 isolates were able to grow at 1 mg/liter on echinocandin-containing plates, yielding a total of 32 phenotypically resistant colonies; however, FKS2 mutations (ΔF658, S663P, W715L, and E655A) were observed only in 21 colonies. We did not find differences in biofilm formation, the kinetic parameters studied, or the median survival of larvae infected by wild-type isolates and the resulting individual FKS2 mutant colonies. Echinocandin concentrations lower than 2 mg/liter can lead to selection of resistance mutations in C. glabrata isolates in vitro.

Antimicrobial activity of essential oil s in the treatment of microorganisms involved in crohn disease

Background: Crohn Disease (CD) is an inflammatory disease with unknown etiology that affects the gastrointestinal tract resulting in tissue damage having clinical symptoms like fever, abdominal pain, diarrhea, fatigue, weight loss and anemia leaving the patient imunodepressive causing risks of opportunistic infection. Recurrent infections in the gastrointestinal tract can also serve as a trigger for the onset of the syndrome. The treatment with medications can bring side effects and for this reason the present study evaluates the activity of the extract of Syzygium aromaticum (clove), on the most incident microorganisms proposing to display it as a possible alternative treatment for patients with this disease. Aim: To evaluate the antimicrobial activity of Syzygium aromaticum against the most common microorganisms involved in CD. Methods: 10 mL of crude extract of clove were obtained by distillation and later tested by antibiogram in clinical strains of Candida albicans, one of the microorganisms of higher incidence in the disease. Results: By adding the disks containing the extract colonies diluted in salina to 0.5 according to McFarland scale (approximately 1.5 x 10 8 CFU / ml) arranged in Sabouraud agar plates incubated at 96,8o F for 24 hours was observed the formation of 10 mm inhibition halos demonstrating the antimicrobial effect of the extract on Candida albicans colonies. Discussion: Several known medicines were obtained from natural sources, including consecrated antibiotics, demonstrating the importance of the study and application of natural products. Conclusion: The extract tested was considered efficient in its antifungal activity and new researches and confirmatory tests are necessary for this and other natural extracts so that they can be applied in the promotion of health causing fewer side effects and at a lower cost.

Prevalence of Candida albicans and carriage of Candida non-albicans in the saliva of preschool children, according to their caries status

Objective: This study was conducted to establish associations among the Candida carriage rate, the diversity of Candida species carried and the different caries status of preschool children.Materials and methods: Sixty-one children between 2 and 5 years of age were examined by a single expert examiner and were divided into three groups, the caries-free, moderate caries and severe caries groups, according to the criteria of the International Caries Detection and Assessment System II (ICDAS). Saliva samples were obtained from the members of each group and were plated on Sabouraud agar plates to assess the Candida carriage rates. CHROMagar Candida medium was used for the preliminary screening. Biochemical testing or PCR/sequencing was conducted to identify the different Candida species in the samples. The differences observed were considered significant if the p value was <0.05.Results: The Candida carriage rate and the number of species of this fungus carried were higher in the group with the highest level of caries severity (p < 0.05). Whereas Candida albicans was the most predominant Candida species in the saliva of all of the children, C. dubliniensis was identified only in the most caries-affected group in addition to other rare species of Candida non-albicans.Conclusions: A high salivary Candida carriage rate and the presence of specific species of this fungus (such as C. albicans and C. dubliniensis) appear to be related to the severity of caries experienced by preschool children.

Fluorescence of Candida in diagnosis of oral candidiasis.

Many pathogenic fungi fluoresce in hematoxylin and eosin stained sections, and Papanicolaou (PAP)-stained smears under ultraviolet illumination. In theory, this phenomenon could aid in the diagnosis of common fungal infections without the delay which is usually associated with special stains. To evaluate the role of fluorescence as a rapid screening technique for oral infections caused by Candida organisms in exfoliative smears of oral candidiasis. Two smears and one swab were collected from each of 62 clinically diagnosed cases of oral candidiasis. Smears were stained with (PAP) and periodic acid-Schiff stain (PAS). Both smears were evaluated under light microscopy (LM). Later, PAP smears were observed under fluorescent microscopy (PAP-FM). The swab was inoculated on Sabouraud's agar plate. Each technique was evaluated for sensitivity and specificity. It was found that the PAS-stained smears were more reliable for detection of Candida species than other methods (sensitivity = 100%; specificity = 66.7%). The PAP-LM and PAP-FM showed less sensitivity (67.9% and 85.7%) and specificity (66.7% and 33.3%), respectively. Combined results of both light and fluorescent microscopy of PAP (LM + FM) showed increased sensitivity (89.3%) but reduced specificity (16.7%). PAP autofluorescence is less sensitive than PAS, still it accentuates the distinct morphological features of Candida.

Non-Seasonal Variation of Airborne Aspergillus Spore Concentration in a Hospital Building.

Nosocomial fungal infections are gaining increased attention from infectiologists. An adequate investigation into the levels of airborne Aspergillus and other fungal spores in hospital settings, under normal conditions, is largely unknown. We monitored airborne spore contamination in a Swiss hospital building in order to establish a seasonally-dependent base-line level. Air was sampled using an impaction technique, twice weekly, at six different locations over one year. Specimens were seeded in duplicate on Sabouraud agar plates. Grown colonies were identified to genus levels. The airborne Aspergillus spore concentration was constantly low throughout the whole year, at a median level of 2 spores/m3 (inter-quartile range = IQR 1–4), and displayed no seasonal dependency. The median concentration of other fungal spores was higher and showed a distinct seasonal variability with the ambient temperature change during the different seasons: 82 spores/m3 (IQR 26–126) in summer and 9 spores/m3 (IQR 6–15) in winter. The spore concentration varied considerably between the six sampling sites in the building (10 to 26 spores/m3). This variability may explain the variability of study results in the literature.

A protocol for microbiologically safe preparation, storage, and use of autologous serum eye-drops in low-income countries.

The study aimed to investigate whether the preparation, storage, and use of autologous serum in insulin syringes is microbiologically safe. Blood samples (10 mL) were obtained from 10 volunteers. After centrifugation, the supernatant serum was removed and distributed in 5 sterile insulin syringes for each sample; syringes were numbered 0 to 4 and labelled with the subject's details. Syringes were immediately transported to the microbiology laboratory and stored in a refrigerator at +4°C. The "0" labelled syringes were separated from the others and 100 µl of serum from each syringe was immediately seeded on chocolate and Sabouraud agar plates, which were incubated aerobically at 37°C for 96 hours to detect any bacterial and/or fungal contamination. In the next 4 days, the same procedure was repeated for the remaining syringes: on day 1, the "1" labelled syringes were analyzed; on day 2, the "2" labelled ones, and so on. In a second experiment, blood samples were obtained from 5 different volunteers. The same procedure as above was followed, but each syringe was used for repeated cultures at 2-hour intervals, for a total of 12 cultures/day. The needle was removed and replaced for each inoculation and the syringes were stored in the refrigerator after use. Under these experimental conditions, none of the cultures showed microbial growth. Results suggest that, under the protocol described, preparation, storage and use of undiluted autologous serum in insulin syringes is inexpensive, fast, and microbiologically safe. This is of great importance for low-income countries.

Biofilms of Candida albicans serotypes A and B differ in their sensitivity to photodynamic therapy.

Candida albicans is classified into different serotypes according to cell wall mannan composition and cell surface hydrophobicity. Since the effectiveness of photodynamic therapy (PDT) depends on the cell wall structure of microorganisms, the objective of this study was to compare the sensitivity of in vitro biofilms of C. albicans serotypes A and B to antimicrobial PDT. Reference strains of C. albicans serotype A (ATCC 36801) and serotype B (ATCC 36802) were used for the assays. A gallium-aluminum-arsenide laser (660 nm) was used as the light source and methylene blue (300 μM) as the photosensitizer. After biofilm formation on the bottom of a 96-well microplate for 48 h, each Candida strain was submitted to assays: PDT consisting of laser and photosensitizer application (L + P+), laser application alone (L + P-), photosensitizer application alone (L-P+), and application of saline as control (L-P-). After treatment, biofilm cells were scraped off and transferred to tubes containing PBS. The content of the tubes was homogenized, diluted, and seeded onto Sabouraud agar plates to determine the number of colony-forming units (CFU/mL). The results were compared by analysis of variance and Tukey test (p < 0.05). The two strains studied were sensitive to PDT (L + P+), with a log reduction of 0.49 for serotype A and of 2.34 for serotype B. Laser application alone only reduced serotype B cells (0.53 log), and the use of the photosensitizer alone had no effect on the strains tested. It can be concluded that in vitro biofilms of C. albicans serotype B were more sensitive to PDT.

Phytochemistry and antimicrobial activity of Zanthoxylum zanthoxyloides root used as chewing stick in Nigeria

This study examined the antimicrobial activity of aqueous and ethanolic extracts of Zanthoxylum zanthoxyloides root fractioned with chloroform against oral microbial isolates. Oral swabs were collected from 25 patients with dental problems attending the Dental clinic of UBTH Benin City. The streak plate method was used to culture on Blood, Chocolate, MacConkey and Sabouraud agar plates and were incubated at 37°C for 24 h for bacteria and room temperature for 72 h for fungi. The paper disc diffusion method was used at 100 mg/ml, 200 mg/ml, 400 mg/ml and 800 mg/ml for antimicrobial determination. The percentage occurrences of the microbial isolates were N. catarrhalis (48%), S. aureus (44%), P. aeruginosa (28%), S. epidermidis (24%), L. acidophilus (24%), K. rhinoscleromatis (20%) and C. albicans (12%). At 800 mg/ml the pre- fractioned and post- fractioned aqueous extracts inhibited all the microbial isolates. Ethanol-chloroform extract at 800 mg/ml inhibited all the microbial isolates except P. aeruginosa that had 42.9%. In all the extracts, C. albicans had 100% inhibition at 400 mg/ml. There was significant difference between the zones of inhibition of the difference microorganisms as P&lt;0.05 and between pre- fractioned and post- fractioned aqueous extracts as P&lt;0.05. The results showed that aqueous extracts had better antimicrobial activity when compared to the ethanol extracts.