Aims: Candida species cause a wide spectrum of diseases, including hospital-acquired and device-associated infections. The biofilm formation is a major virulence factor in Candida pathogenesis and the cells in biofilm show enhanced resistance to disinfectants. Our aim was to evaluate the efficiency of the commonly used hospital disinfectants (glutaraldehyde (GLU), hydrogen peroxide (HP), peracetic acid (PA), ortho-phtalaldehyde (OPA) and sodium hypochlorite (SH) on biofilms of clinical Candida (C. albicans, C. glabrata, C. parapsilosis, C. krusei and C. tropicalis) isolates. Study Design: An experimental study. Place and Duration of Study: Department of Microbiology, Faculty of Medicine and Electron Microscope Laboratory, Eskisehir Osmangazi University, between January 2011 and May 2011. Methodology: These disinfectants were selected due to their common application in hospital environment. Their concentrations were adjusted to manufacturer’s recommendations for instrument disinfection: 5% HP, 0.2% PA, 5.25% SH (5000 ppm of chlorine), 2% GLU and 0.55% OPA. They were also prepared at the 1:2 and 1:4 times of recommended concentration to evaluate the activity of lower concentrations. The biofilms were grown in microplates and treated with disinfectants at contact times 1, 5 and 10 minutes (20 min for GLU), then stained with the biomass indicator (2, 3-Bis [2-methoxy-4-nitro-5-(sulfenylamino) carbonyl-2H-tetrazolium-hydroxide]). Results: The disinfectants reduced the biofilm for all concentrations studied, however none of them completely removed the biofilm. When they were used at low concentration, longer contact times were more effective. However, when the disinfectants were used in recommended concentration, results showed many variations depending on the disinfectant type, contact times and species. Conclusion: Our results also emphasize the importance of regular disinfection, before the starting of biofilm formation.
Background: High incidence of nosocomial infections has led to prolonged hospitalization, leading to high morbidity and mortality. Our research was aimed at determining the prevalence as well as identification and isolation of aerobic bacteria responsible for nosocomial urinary tract infection. Methods: Study was conducted at Gadarif Teaching Hospital, Gadarif State, Eastern Sudan, from April 2004 to March 2005. The study was designed to isolate aerobic bacteria causing urinary tract infections, and to determine the antibiograms of the isolated bacteria to commonly used antibiotics. Results: Out of 783 specimens collected during the study, 611 (79.03%) midstream urine specimens were collected from patients after urinary catheterization. 100 (12.77%) aerobic bacterial species were isolated from these specimens, they were P. aeruginosa (37%), K. pneumoniae (23%), P. mirabilis (22%), P. vulgaris (12%) and E. coli (6%); The antibiograms of the isolates (n=263) shows sensitivity and resistant to S. aureus (n=103), P. mirabilis (n=63), P. aeruginosa (n=49), K. pneumoniae (n=23), P. vulgaris (n=14) and E. coli (n=11) bacteria to various antibiotics including Vancomycin, Fusidic acid, Gentamicin, Ciprofloxacin, Penicillin G, Ceftazidime, Methicillin, Cephelaxin, Nalidixic acid, Nitrofurantoin, Ceftazidime, Ofloxacin, Co-trimoxazole and Ciprofloxacin.
Aims: To investigate in vitro antifungal activities of methanol, hexane and cold water extracts of Cassia alata, Mitracarpus villosus and Lawsonia inermis against non-dermatophyte molds isolated from rice farmers with onychomycosis in Anambra State, Nigeria. Study Design: Examination of antifungal activity of medicinal plants among cross-section of farmers. Place and Duration of Study: Department of Applied Microbiology and Brewing, Nnamdi Azikiwe University Awka. Anambra State, Nigeria between November 2009 and June 2011. Methodology: Clinical samples were collected from 135 rice farmers in Anambra State, Nigeria and identified. Dried leaves of C. alata, M. villosus and L. inermis were extracted by soxhlet using methanol and hexane as solvents. Cold water extraction was also carried out using fresh leaves. The extracts were tested against the isolated non-dermatophyte molds using disc diffusion method at varying concentrations (10mg, 20mg, 40mg, 80mg). Discs impregnated with 2% dimethylsulphoxide were used as negative control while those impregnated with 2mg/disc ketoconazole served as positive control. The Minimum Inhibitory Concentration (MIC) and Minimum Fungicidal Concentration (MIC) of the crude extracts were assayed for against the test isolates. Results: The organisms recovered included Aspergillus terrus, Aspergillus sclerotiorum, Aspergillus flavus, Fusarium sp., Chrysosporium sp. and Scopulariopsis sp. The organisms were sensitive to all the methanol extracts of medicinal plants with minimum inhibitory concentration range of 10-40mg/disc except A. flavus which was inhibited only by L. inermis extract at concentration of 40mg/disc. The mean zone of inhibition produced ranged between 6.0mm and 14.2mm with C. alata extract showing the highest zone of inhibition (14.2mm) against Fusarium sp. The standard Ketoconazole range was 6.0-12.4mm diameter. Hexane extract of L. inermis inhibited all isolates at 20-40mg/disc concentration. A. flavus resisted hexane extracts of C. alata and M. villosus, while A. terrus resisted extract of M. villosus alone. All isolates except A. flavus were sensitive to cold water extract of L. inermis with diameter zone of inhibition range of 6.2-8.2mm. Methanol extracts of C. alata and L. inermis showed fungicidal actions against all test isolates at 10-40mg/disc range except for A. flavus. Conclusion: The various antifungal extracts showed inhibitory/fungicidal effect against the isolated non-dermatophyte molds which compared favorably with that of standard antifungal drug, ketoconazole. The plant leaves could serve as sources for development of new antifungal drugs.
Aims: To detect ESBL-producing E. coli isolates and the genes underlying their resistance to β-lactams and sulfamethoxazole. Place and Duration of Study: Department of Medical Laboratory Sciences, Jordan University of Science & Technology, Irbid 22110, Jordan, between January 2009 and December 2010. Methodology: The blaCTX-M, blaTEM, blaSHV genes and sul genes were tested for in 165 urinary E. coli isolates by PCR assays. The association between the presence of gene and the antibiotic resistant was analyzed. Results: Multidrug resistance was detected among the isolates. Eighty-three (50.3%) of the isolates were ESBL-producing, 67(80.7%) had either blaCTX-M or blaTEM, or both and none had blaSHV gene, sul2 (41.2%) was prevalent (21.8%) isolates had two sul genes, while (1.8%) isolates had three sul genes. A significant association (p ≤ 0.05) was found between blaCTX-M, or blaTEM and resistance to several antibiotics e.g., cefixime. Several (29.9%) of the ESBL-producing strains harbored multiple ESBL genes and had high resistance to various antibiotic classes. Conclusion: The results revealed a high-level of sul2 and blaCTX-M positive ESBL isolates among other β-lactam resistant genes circulating in the community. These findings indicate that these patients are more likely to have ineffective initial empirical antimicrobial therapy.
The diversity and abundance of arbuscular mycorrhizal fungi (AMF) was assessed in the Kumaon Himalayan foothills. Four typical ecosystems were selected in the Sat-Tal area located in the Nainital, district in Uttarakhand, India, representing vegetation change due to human settlement and selective logging of native oak. Besides a natural oak forest, a mixed pine-oak forest, a pure pine stand and an arable field were sampled. The latter was cropped with black gram (Vigna mungo L. Hepper) and maize (Zea mays L.) during the rainy season from June to September and rotated with wheat (Triticum aestivum L.) during winter for the last 10 years. Only cow dung compost used for fertilization. The highest AMF spore abundance throughout the year was recorded in soil samples from the pine-oak mixed forest, followed by the pine and oak forests and the agricultural field. At all sites, the lowest spore abundance was recorded at the end of the winter season in March, and the highest in October after the rainy season. Whereas in October, Glomus claroideum, Acaulospora scrobiculata and A. spinosa were found at all sites, in March it was only G. intraradices which occurred everywhere. The highest AMF spore morphotype richness was recorded in samples from the oak forest. In AMF-trap cultures set up with field soil inocula, the dominant species recovered were G. intraradices, G. etunicatum and A. scrobiculata. As compared to the field samples, trap culturing of one year enhanced spore abundance but entailed a loss of AMF richness. The study revealed differences in AMF community composition and structure among sites characterized by different land use systems.
Aims: To isolate, identify and evaluate the genetic diversity and antimicrobial susceptibility of F. nucleatum recovered from Nigerian patients with chronic periodontitis. Study Design: Cross-sectional design. Place and Duration of Study: Department of Medical Microbiology and Parasitology, College of Medicine, University of Lagos, between January 2007 and July 2008. Methodology: We analyzed F. nucleatum species recovered from Nigerian patients with chronic periodontitis. Bacterial identification was done using colonial morphology; Grams stain reaction, conventional biochemical tests, API 20-A and Polymerase chain reaction (PCR). The minimum inhibitory concentration (MIC) of 6 antibiotics was determined by agar dilution method on Brucella blood agar while the bacterial genetic diversity was studied using the Arbitrarily Primed-PCR (AP-PCR) method with the arbitrary primer OPA-05. The inter-relationship and genetic similarity matrix among the isolates was determined and by Numerical taxonomy and multivariate analysis system (NTSYS-pc) statistical package. Results: We obtained 48 isolates of F. nucleatum from 50 Nigerian patients (28 males and 22 females) with chronic periodontitis. They were susceptible to metronidazole, clindamycin, cefoxitin, tetracycline, amoxicillin and clavulanate. One was resistant to amoxicillin (MIC >32 µg/ml) and produced β-lactamase. The isolates were further placed into five groups (A, B, C, D and E) based on their AP-PCR profile. Conclusion: The AP-PCR analysis showed heterogeneity among strains. By using AP-PCR, we observed a single β-lactamase producing clone resistant to amoxicillin which eventually formed a distinct group showing that such genetic difference may have contributed to the formation of a separate clone.
Introduction: Citrinin is a mycotoxin originally isolated from Penicillium citrinum. It has been found to be produced by a variety of other fungi (Aspergillus niveus, Aspergillus ochraceus, Aspergillus oryzae, Aspergillus terreus, Monascus ruber, Monascus purpureus and Penicillium camemberti) which are found or used in the production of human foods (Abramson et al., 1999). The inhibitory effect of plant extracts on citrinin biosynthesis have been examined (Mossini and Kemmelmeier, 2008; Reddy et al., 2010). They found that all the tested plant extracts reduced the citrinin production. Shimizu et al. (2005, 2007) found that the pksCT gene was essential for citrinin biosynthesis in M. purpureus. Also Sakai et al. (2008) reported that introducing additional copies of an activator gene (ctnA), controlled by the Aspergillus nidulans trpC promoter, into the citrinin-cluster-containing transformants enhanced the transcription of all the genes in the cluster and resulted in an almost 400-fold higher citrinin production compared to that of the parental transformant. Aims: To give idea on physicochemical properties of citrinin, its production, effects of some plant extracts on it and gene involved in citrinin biosynthesis. Study Design: Review study. Place and Duration of Study: Department of Biology, Faculty of Science, Taif- Saudi Arabia and Department of Botany, Faculty of Science, Tanta-Egypt. 2011-2012. Methodology: Citrinin was produced in liquid potato-dextrose medium (PD) or in glucose medium. The citrinin was extracted three times with chloroform (1:1 v/v), pooled and concentrated in vacuo at 40ºC using a rotary evaporator. The crude extract was diluted in minimum amount of chloroform (2 ml) and citrinin was estimated by thin layer chromatography (TLC). Effects of some plant extracts like neem leaf extract and some medicinal plants were determined. Conclusion: This review was written with the aim of demonstrating the scope of citrinin production, various analytical techniques in citrinin detection and estimation and effects of some plant extracts and genes on citrinin biosynthesis. It was found that plant extracts can be used as a potential source of sustainable ecofriendly botanical fungicides to protect food grains from toxigenic P. citrinum and citrinin accumulation under storage conditions.