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Garrine M, Matambisso G, Nobela N, Vubil D, Massora S, Acácio S, Nhampossa T, Alonso P, Mandomando I. Low frequency of enterohemorrhagic, enteroinvasive and diffusely adherent Escherichia coli in children under 5 years in rural Mozambique: a case-control study. BMC Infect Dis 2020; 20:659. [PMID: 32894092 PMCID: PMC7475947 DOI: 10.1186/s12879-020-05380-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Accepted: 08/28/2020] [Indexed: 11/10/2022] Open
Abstract
Background Diarrheagenic Escherichia coli (DEC) are among the leading pathogens associated with endemic diarrhea in low income countries. Yet, few epidemiological studies have focused the contribution of enterohemorrhagic E. coli (EHEC), enteroinvasive E. coli (EIEC) and diffusely adherent E. coli (DAEC). Methods We assessed the contribution of EHEC, EIEC and DAEC isolated from stool samples from a case-control study conducted in children aged < 5 years in Southern Mozambique between December 2007 and November 2012. The isolates were screened by conventional PCR targeting stx1 and stx2 (EHEC), ial and ipaH (EIEC), and daaE (DAEC) genes. Results We analyzed 297 samples from cases with less-severe diarrhea (LSD) matched to 297 controls, and 89 samples from cases with moderate-to-severe diarrhea (MSD) matched to 222 controls, collected between November 3, 2011 and November 2, 2012. DEC were more common among LSD cases (2.7%, [8/297] of cases vs. 1.3% [4/297] of controls; p = 0.243]) than in MSD cases (0%, [0/89] of cases vs. 0.4%, [1/222] of controls; p = 1.000). Detailed analysis revealed low frequency of EHEC, DAEC or EIEC and no association with diarrhea in all age strata. Although the low frequency, EIEC was predominant in LSD cases aged 24–59 months (4.1% for cases vs. 0% for controls), followed by DAEC in similar frequency for cases and controls in infants (1.9%) and lastly EHEC from one control. Analysis of a subset of samples from previous period (December 10, 2007 and October 31, 2011) showed high frequency of DEC in controls compared to MSD cases (16.2%, [25/154] vs. 11.9%, [14/118], p = 0.383, respectively). Among these, DAEC predominated, being detected in 7.7% of cases vs. 17.6% of controls aged 24–59 months, followed by EIEC in 7.7% of cases vs. 5.9% of controls for the same age category, although no association was observed. EHEC was detected in one sample from cases and two from controls. Conclusions Our data suggests that although EHEC, DAEC and EIEC are less frequent in endemic diarrhea in rural Mozambique, attention should be given to their transmission dynamics (e.g. the role on sporadic or epidemic diarrhea) considering that the role of asymptomatic individuals as source of dissemination remains unknown.
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Affiliation(s)
- Marcelino Garrine
- Centro de Investigação em Saúde de Manhiça (CISM), Maputo, Mozambique.,Global Health and Tropical Medicine (GHTM), Instituto de Higiene e Medicina Tropical (IHMT), Universidade Nova de Lisboa (UNL), Lisbon, Portugal
| | - Glória Matambisso
- Centro de Investigação em Saúde de Manhiça (CISM), Maputo, Mozambique
| | - Nélio Nobela
- Centro de Investigação em Saúde de Manhiça (CISM), Maputo, Mozambique
| | - Delfino Vubil
- Centro de Investigação em Saúde de Manhiça (CISM), Maputo, Mozambique
| | - Sérgio Massora
- Centro de Investigação em Saúde de Manhiça (CISM), Maputo, Mozambique
| | - Sozinho Acácio
- Centro de Investigação em Saúde de Manhiça (CISM), Maputo, Mozambique.,Instituto Nacional de Saúde (INS), Ministério da Saúde, Maputo, Mozambique
| | - Tacilta Nhampossa
- Centro de Investigação em Saúde de Manhiça (CISM), Maputo, Mozambique.,Instituto Nacional de Saúde (INS), Ministério da Saúde, Maputo, Mozambique
| | - Pedro Alonso
- Centro de Investigação em Saúde de Manhiça (CISM), Maputo, Mozambique.,ISGlobal, Hospital Clínic-Universitat de Barcelona, Barcelona, Spain
| | - Inácio Mandomando
- Centro de Investigação em Saúde de Manhiça (CISM), Maputo, Mozambique. .,Instituto Nacional de Saúde (INS), Ministério da Saúde, Maputo, Mozambique.
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Novickij V, Grainys A, Švedienė J, Paškevičius A, Novickij J. Controlled inactivation of Trichophyton rubrum using shaped electrical pulse bursts: Parametric analysis. Biotechnol Prog 2016; 32:1056-60. [PMID: 27071774 DOI: 10.1002/btpr.2276] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2015] [Revised: 04/07/2016] [Indexed: 01/15/2023]
Abstract
The dermatophytes infect the skin by adherence to the epidermis followed by germination, growth, and penetration of the fungal hyphae within the cells. The aim of this study was to investigate the efficacy of the pulsed electric fields (PEF) of controlled inactivation of Trichophyton rubrum (ATCC 28188). In this work, we have used bursts of the square wave PEF pulses of different intensity (10-30 kV/cm) to induce the irreversible inactivation in vitro. The electric field pulses of 50 µs and 100 µs have been generated in bursts of 5, 10, and 20 pulses with repetition frequency of 1 Hz. The dynamics of the inactivation using different treatment parameters were studied and the inactivation map for the T. rubrum has been defined. Further, the combined effect of PEF with the antifungal agents itraconazole, terbinafine, and naftifine HCl was investigated. It has been demonstrated that the combined effect results in the full inactivation of T. rubrum colony. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:1056-1060, 2016.
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Affiliation(s)
- Vitalij Novickij
- High Magnetic Field Inst., Vilnius Gediminas Technical University, Vilnius, 03227, Lithuania
| | - Audrius Grainys
- High Magnetic Field Inst., Vilnius Gediminas Technical University, Vilnius, 03227, Lithuania
| | - Jurgita Švedienė
- Laboratory of Biodeterioration Research, Nature Research Centre, Vilnius, 08412, Lithuania
| | - Algimantas Paškevičius
- Laboratory of Biodeterioration Research, Nature Research Centre, Vilnius, 08412, Lithuania.,Laboratory of Microbiology of the Centre of Laboratory Medicine, Vilnius University Hospital Santariškių Clinics, Vilnius, Lithuania
| | - Jurij Novickij
- High Magnetic Field Inst., Vilnius Gediminas Technical University, Vilnius, 03227, Lithuania
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Odetoyin BW, Hofmann J, Aboderin AO, Okeke IN. Diarrhoeagenic Escherichia coli in mother-child Pairs in Ile-Ife, South Western Nigeria. BMC Infect Dis 2016; 16:28. [PMID: 26809819 PMCID: PMC4727348 DOI: 10.1186/s12879-016-1365-x] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2015] [Accepted: 01/19/2016] [Indexed: 11/21/2022] Open
Abstract
Background Diarrhoeagenic Escherichia coli (DEC) pathotypes are among the most common bacterial causes of morbidity and mortality in young children. These pathogens are not sought routinely and capacity for their detection is limited in Africa. We investigated the distribution and dissemination of DEC in 126 children paired with their mothers in a Nigerian community. Methods A total of 861 E. coli were isolated from 126 children with diarrhoea and their mothers. Antimicrobial susceptibility of each isolate was determined by Kirby-Bauer disc diffusion technique. All the isolates were screened for DEC markers by multiplex PCR. Genetic relatedness of DEC strains was determined by flagellin typing and Insertion element 3 (IS3)-based PCR. Results DEC were identified from 35.7 % of individuals with the most common pathotype being shiga toxin-producing E. coli (42, 16.7 %). Identical pathotypes were found in 13 (10.3 %) of the mother-child pairs and in three of these strains from mothers and their children showed identical genetic signatures. Over 90 % of DEC isolates were resistant to ampicillin, sulphonamide, tetracycline, streptomycin or trimethoprim, but only 9 (7.2 %) were ciprofloxacin resistant Conclusion The data suggest that healthy mothers are asymptomatic reservoirs of multiply-resistant strains that are pathogenic in their children and there are instances in which identical strains are found in mother-child pairs.
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Affiliation(s)
- Babatunde W Odetoyin
- Department of Medical Microbiology and Parasitology, Obafemi Awolowo University, Ile-Ife, Nigeria.
| | - Jennifer Hofmann
- Department of Biology, Haverford College, 370 Lancaster Avenue, Haverford, PA, 19041, USA.
| | - Aaron O Aboderin
- Department of Medical Microbiology and Parasitology, Obafemi Awolowo University, Ile-Ife, Nigeria.
| | - Iruka N Okeke
- Department of Biology, Haverford College, 370 Lancaster Avenue, Haverford, PA, 19041, USA. .,Faculty of Pharmacy, University of Ibadan, Ibadan, Nigeria.
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Titilawo Y, Obi L, Okoh A. Occurrence of virulence gene signatures associated with diarrhoeagenic and non-diarrhoeagenic pathovars of Escherichia coli isolates from some selected rivers in South-Western Nigeria. BMC Microbiol 2015; 15:204. [PMID: 26449767 PMCID: PMC4599032 DOI: 10.1186/s12866-015-0540-3] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2015] [Accepted: 09/30/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Diarrhoeal diseases are attributable to unsafe water stemming from improper sanitation and hygiene and are reportedly responsible for extensive morbidity and mortality particularly among children in developed and developing countries. METHODS Water samples from selected rivers in Osun State, South-Western Nigeria were collected and analyzed using standard procedures. Escherichia coli isolates (n=300) were screened for 10 virulence genes using polymerase chain reaction for pathotyping. RESULTS While the virulence gene (VG) lt for enterotoxigenic E. coli had the highest prevalence of 45%, the enteropathogenic E. coli genes eae and bfp were detected in 6 and 4% of the isolates respectively. The VGs stx1 and stx2 specific for the enterohemorrhagic E. coli pathotypes were detected in 7 and 1% of the isolates respectively. Also, the VG eagg harboured by enteroaggregative pathotype and diffusely-adherent E. coli VG daaE were detected in 2 and 4% of the isolates respectively and enteroinvasive E. coli VG ipaH was not detected. In addition, the VGs papC for uropathogenic and ibeA for neonatal meningitis were frequently detected in 19 and 3% of isolates respectively. CONCLUSIONS These findings reveal the presence of diarrhoeagenic and non-diarrhoeagenic E. coli in the selected rivers and a potential public health risk as the rivers are important resources for domestic, recreational and livelihood usage by their host communities.
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Affiliation(s)
- Yinka Titilawo
- SAMRC Microbial Water Quality Monitoring Centre, University of Fort Hare, Alice, 5700, South Africa. .,Applied and Environmental Microbiology Research Group, Department of Biochemistry and Microbiology, University of Fort Hare, Alice, 5700, South Africa.
| | - Larry Obi
- SAMRC Microbial Water Quality Monitoring Centre, University of Fort Hare, Alice, 5700, South Africa. .,Applied and Environmental Microbiology Research Group, Department of Biochemistry and Microbiology, University of Fort Hare, Alice, 5700, South Africa.
| | - Anthony Okoh
- SAMRC Microbial Water Quality Monitoring Centre, University of Fort Hare, Alice, 5700, South Africa. .,Applied and Environmental Microbiology Research Group, Department of Biochemistry and Microbiology, University of Fort Hare, Alice, 5700, South Africa.
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Efinaconazole Topical Solution, 10%: Factors Contributing to Onychomycosis Success. J Fungi (Basel) 2015; 1:107-114. [PMID: 29376902 PMCID: PMC5753103 DOI: 10.3390/jof1020107] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2015] [Revised: 06/23/2015] [Accepted: 06/24/2015] [Indexed: 11/16/2022] Open
Abstract
To provide an adequate therapeutic effect against onychomycosis, it has been suggested that topical drugs should have two properties: drug permeability through the nail plate and into the nail bed, and retention of their antifungal activity in the disease-affected areas. Only recently has the importance of other delivery routes (such as subungual) been discussed. Efinaconazole has been shown to have a more potent antifungal activity in vitro than the most commonly used onychomycosis treatments. The low keratin affinity of efinaconazole contributes to its effective delivery through the nail plate and retention of its antifungal activity. Its unique low surface tension formulation provides good wetting properties affording drug delivery both through and under the nail. High antifungal drug concentrations have been demonstrated in the nail of onychomycosis patients, and effectiveness of efinaconazole topical solution, 10% confirmed in two large well-controlled multicenter Phase 3 clinical studies in patients with mild-to-moderate disease.
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Boisen N, Melton-Celsa AR, Scheutz F, O'Brien AD, Nataro JP. Shiga toxin 2a and Enteroaggregative Escherichia coli--a deadly combination. Gut Microbes 2015; 6:272-8. [PMID: 26039753 PMCID: PMC4615819 DOI: 10.1080/19490976.2015.1054591] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
In 2011, a Shiga toxin (Stx) type 2a-producing enteroaggregative E. coli (EAEC) strain of serotype O104:H4 caused a large lethal outbreak in Northern Europe. Until recently, the pathogenic mechanisms explaining the high virulence of the strain have remained unclear. Our laboratories have shown that EAEC genes encoded on the pAA virulence plasmid, particularly the AggR-regulated AAF/I fimbriae, enhance inflammation and enable the outbreak strain to both adhere to epithelial cells and translocate Stx2a across the intestinal epithelium, possibly explaining the high incidence of the life threatening post-diarrheal sequelae of hemolytic uremic syndrome. Epidemiologic evidence supports a model of EAEC pathogenesis comprising the concerted action of multiple virulence factors along with induction of inflammation. Here, we suggest a model for the pathogenesis of the O104:H4 outbreak strain that includes contributions from EAEC alone, but incorporating additional injury induced by Stx2a.
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Affiliation(s)
- Nadia Boisen
- Statens Serum Institut; Department of Microbiology and Clinical Control; Copenhagen, Denmark,Correspondence to: Nadia Boisen;
| | - Angela R Melton-Celsa
- Statens Serum Institut; Department of Microbiology and Clinical Control; Copenhagen, Denmark
| | - Flemming Scheutz
- Statens Serum Institut; Department of Microbiology and Clinical Control; Copenhagen, Denmark
| | - Alison D O'Brien
- Department of Microbiology and Immunology; Uniformed Services University of the Health Sciences; Bethesda, MD USA
| | - James P Nataro
- Department of Pediatrics; University of Virginia School of Medicine; Charlottesville, VA USA
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Elsayed MMA. Development of topical therapeutics for management of onychomycosis and other nail disorders: a pharmaceutical perspective. J Control Release 2014; 199:132-44. [PMID: 25481439 DOI: 10.1016/j.jconrel.2014.11.017] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2014] [Revised: 11/14/2014] [Accepted: 11/17/2014] [Indexed: 10/24/2022]
Abstract
The human nail plate is a formidable barrier to drug permeation. Development of therapeutics for management of nail diseases thus remains a challenge. This article reviews the current knowledge and recent advances in the field of transungual drug delivery and provides guidance on development of topical/ungual therapeutics for management of nail diseases, with special emphasis on management of onychomycosis, the most common nail disease. Selection of drug candidates, drug delivery approaches, and evaluation of formulations are among the topics discussed. A comprehensive mathematical description for transungual permeation is also introduced.
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Affiliation(s)
- Mustafa M A Elsayed
- Department of Pharmaceutics, Faculty of Pharmacy, Alexandria University, El-Khartoum Square, El-Azarita, Alexandria 21521, Egypt.
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Sariguzel FM, Koc AN, Yagmur G, Berk E. Interdigital foot infections: Corynebacterium minutissimum and agents of superficial mycoses. Braz J Microbiol 2014; 45:781-4. [PMID: 25477907 PMCID: PMC4204958 DOI: 10.1590/s1517-83822014000300003] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2012] [Accepted: 03/14/2014] [Indexed: 11/27/2022] Open
Abstract
Interdigital foot infections are mostly caused initially by dermatophytes, yeasts and less frequently by bacteria. Erythrasma caused by Corynebacterium minutissimum can be confused with superficial mycoses. The aim of the study was to determine the prevalence of the etiologic agents of superficial mycoses and the frequency of Corynebacterium minutissimum in interdigital foot infections. All the samples obtained from the 121 patients with interdigital foot infections were examined directly with the use of 20% potassium hydroxide mounts and Gram stain under the microscope and cultured on Sabouraud’s dextrose agar plates. In identification of superficial mycoses, the rate was found to be 14% with the cultural method and 14% with direct microscopic examination. Using a combination of direct microscopic examination and culture, a 33.8% ratio was achieved. In the culture of these samples, the most isolated factor was Trichophyton rubrum (33.7%). In 24 of the patients (19.8%) Corynebacterium minutissimum was detected by Gram staining, in 6 of these patients Trichophyton rubrum was found, Trichophyton mentagrophytes was found in 2 and Trichosporon spp. was found in 1. The examination of interdigital foot lesions in the laboratory, the coexistence of erythrasma with dermatophytes and yeast should be considered.
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Affiliation(s)
- Fatma Mutlu Sariguzel
- Department of Microbiology Kayseri Education and Research Hospital Kayseri Turkey Department of Microbiology, Kayseri Education and Research Hospital, Kayseri, Turkey
| | - A Nedret Koc
- Department of Microbiology Erciyes University Medical School Kayseri Turkey Department of Microbiology, Erciyes University Medical School, Kayseri, Turkey
| | - Gülhan Yagmur
- Department of Microbiology Kayseri Education and Research Hospital Kayseri Turkey Department of Microbiology, Kayseri Education and Research Hospital, Kayseri, Turkey
| | - Elife Berk
- Department of Microbiology Kayseri Education and Research Hospital Kayseri Turkey Department of Microbiology, Kayseri Education and Research Hospital, Kayseri, Turkey
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9
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Oguntoyinbo FA. Safety Challenges Associated with Traditional Foods of West Africa. FOOD REVIEWS INTERNATIONAL 2014. [DOI: 10.1080/87559129.2014.940086] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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10
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Synthesis of a pentasaccharide repeating unit of the O-antigen of enteroadherent Escherichia coli O154 strain. ACTA ACUST UNITED AC 2014. [DOI: 10.1016/j.tetasy.2014.03.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Bonkoungou IJO, Haukka K, Österblad M, Hakanen AJ, Traoré AS, Barro N, Siitonen A. Bacterial and viral etiology of childhood diarrhea in Ouagadougou, Burkina Faso. BMC Pediatr 2013; 13:36. [PMID: 23506294 PMCID: PMC3616825 DOI: 10.1186/1471-2431-13-36] [Citation(s) in RCA: 86] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/07/2012] [Accepted: 03/11/2013] [Indexed: 12/05/2022] Open
Abstract
BACKGROUND Diarrhea is the most frequent health problem among children in developing countries. This study investigated the bacterial and viral etiology and related clinical and epidemiological factors in children with acute diarrhea in Ouagadougou, Burkina Faso. METHODS Stool specimens were collected from 283 children under 5 years of age visiting hospital due to acute diarrhea and from 60 healthy controls of similar age. Pathogens were investigated by using conventional culture techniques, PCR and immunochromatographic testing. Salmonella and Shigella strains were serotyped and their susceptibility to 23 antimicrobial agents was determined by the agar dilution method. RESULTS At least one pathogen was detected in 64% of the 283 patients and in 8% of the 60 controls (p < 0.001). Rotavirus was found in 30% of the patients, followed by diarrheagenic Escherichia coli (24%), Salmonella enterica ssp. enterica (9%), Shigella spp. (6%), adenovirus (5%) and Campylobacter spp. (2%). Multiple pathogens were found in 11% of the patients and in 2% of the controls (p = 0.028). Viruses were found mainly in children of ≤ 2 years of age, whereas bacteria were equally prevalent among all the age groups. Viral infections occurred mostly during the cool dry season and the bacterial infections during the rainy season. Fever (64%) and vomiting (61%) were the most common symptoms associated with diarrhea. Only one Salmonella strain was resistant to nalidixic acid and ciprofloxacin. Of the Shigella strains, one was resistant to nalidixic acid but 81% to trimethoprim- sulfamethoxazole, 63% to streptomycin and 50% to ampicillin. Most of all the other Salmonella and Shigella strains were sensitive to all antimicrobials tested. CONCLUSION Rotaviruses and diarrheal E. coli were the most predominant pathogens associated with acute diarrhea in Burkinabe children. Constant antimicrobial surveillance is warranted to observe for the emergence of enteric bacteria resistant to antimicrobials that are important in treatment also of severe infections.
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Affiliation(s)
- Isidore Juste O Bonkoungou
- Bacteriology Unit, National Institute for Health and Welfare (THL), P.O. Box 30, Helsinki 00271, Finland
- Laboratoire de Biologie Moléculaire, d’Epidémiologie et Surveillance des Bactéries et Virus transmis par les Aliments, CRSBAN/UFR-SVT, Université de Ouagadougou, Ouagadougou 03 BP 7021, Burkina Faso
- Laboratoire National de Santé Publique, Ouagadougou 09 BP 24, Burkina Faso
| | - Kaisa Haukka
- Bacteriology Unit, National Institute for Health and Welfare (THL), P.O. Box 30, Helsinki 00271, Finland
- Department of Food and Environmental Sciences, Division of Microbiology, University of Helsinki, P.O. Box 56, Helsinki FI-00014, Finland
| | - Monica Österblad
- Antimicrobial Resistance Unit, National Institute for Health and Welfare (THL), P.O. Box 57, Turku 20521, Finland
| | - Antti J Hakanen
- Antimicrobial Resistance Unit, National Institute for Health and Welfare (THL), P.O. Box 57, Turku 20521, Finland
| | - Alfred S Traoré
- Laboratoire de Biologie Moléculaire, d’Epidémiologie et Surveillance des Bactéries et Virus transmis par les Aliments, CRSBAN/UFR-SVT, Université de Ouagadougou, Ouagadougou 03 BP 7021, Burkina Faso
| | - Nicolas Barro
- Laboratoire de Biologie Moléculaire, d’Epidémiologie et Surveillance des Bactéries et Virus transmis par les Aliments, CRSBAN/UFR-SVT, Université de Ouagadougou, Ouagadougou 03 BP 7021, Burkina Faso
| | - Anja Siitonen
- Bacteriology Unit, National Institute for Health and Welfare (THL), P.O. Box 30, Helsinki 00271, Finland
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Curová K, Kmetová M, Sabol M, Gombosová L, Lazúrová I, Siegfried L. Enterovirulent E. coli in inflammatory and noninflammatory bowel diseases. Folia Microbiol (Praha) 2009; 54:81-6. [PMID: 19330549 DOI: 10.1007/s12223-009-0012-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2008] [Revised: 09/23/2008] [Indexed: 01/07/2023]
Abstract
We determined the incidence of enterovirulent E. coli (EVEC; which can to cause gastrointestinal infections) in strains isolated from patients with both of the major inflammatory bowel diseases (IBD), Crohn's disease (CD) and ulcerative colitis (UC) and from patients with noninflammatory bowel diseases (nonIBD). Cell detachment E. coli (CDEC) were detected in 14 % of all strains. A significant difference in the presence of CDEC was found between the groups of strains isolated from UC (24.1 %), nonIBD (11.9 %) and CD (4.7 %). Enteroaggregative E. coli (EAggEC) were detected in 2.5 %, typical enteropathogenic strains (EPEC) in 1.3 % and enterotoxigenic ones (ETEC) in 1.5 %. Enteroinvasive (EIEC) and shigatoxin producing E. coli (STEC) were not detected. Some strains showed a high invasion level in gentamicin-protection assay. These strains could therefore belong to adherent-invasive E. coli (AIEC) because they are free of genes encoding invasins (ipaH, ial) and are equipped with fimA gene. However, complete characterization of these strains and their classification as AIEC will require further tests.
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Affiliation(s)
- K Curová
- Institute of Medical Microbiology and Clinical Microbiology, Pavol Jozef Safárik University in Kosice, Slovakia
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Yamasaki S, Asakura M, Tsukamoto T, Faruque SM, Deb R, Ramamurthy T. CYTOLETHAL DISTENDING TOXIN (CDT): GENETIC DIVERSITY, STRUCTURE AND ROLE IN DIARRHEAL DISEASE. TOXIN REV 2008. [DOI: 10.1080/15569540500320938] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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15
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Tsuboi R, Yamazaki M, Matsuda Y, Uchida K, Ueki R, Ogawa H. Antisense oligonucleotide targeting fibroblast growth factor receptor (FGFR)-1 stimulates cellular activity of hair follicles in an in vitro organ culture system. Int J Dermatol 2007; 46:259-63. [PMID: 17343580 DOI: 10.1111/j.1365-4632.2007.03018.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
BACKGROUND The hair cycle is regulated by various molecules, among which FGF-5 has been shown to promote the transition from anagen to catagen. The FGFR-1, a trans-membrane receptor of FGF-5 with tyrosine kinase activity, is localized in the follicular papilla of hair follicles. OBJECTIVES In order to apply the antisense oligonucleotides targeting FGFR-1 as a treatment for baldness, we examined the effect of the oligonucleotides on hair follicle growth in a serum-free organ culture system. METHODS Vibrissal hair follicles from C3H/He mice were cultured in the presence of a reagent at 31 degrees C in 95% O(2)-5% CO(2) for 72 h. A 20-mer antisense nucleotide and its randomly arranged counterpart were prepared by predicting the effective target site of FGFR-1 mRNA. Cellular activity in the hair bulb was estimated by measuring the fluorescence intensity (FI) of the medium after incubation with AlamarBlue dye. RESULTS The addition of 30 microM of the phosphorothioate form of antisense oligonucleotide (A1561TS) to the media increased the FI by 30%, whereas the control produced no detectable change. This effect was reproducible dose-dependent with maximal stimulation at 30 microM. Incorporation of the oligonucleotide into the follicular papilla was histologically confirmed by incubation with FITC-labeled phosphorothioate oligonucleotides, and the intact morphological structure of the hair bulb was maintained intact after a 72-h incubation. CONCLUSIONS These results suggest the clinical utility of antisense nucleotide targeting FGFR-1 as a treatment for baldness.
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Affiliation(s)
- R Tsuboi
- Department of Dermatology, Tokyo Medical University, Tokyo, Japan.
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Smith JL, Bayles DO. The contribution of cytolethal distending toxin to bacterial pathogenesis. Crit Rev Microbiol 2007; 32:227-48. [PMID: 17123907 DOI: 10.1080/10408410601023557] [Citation(s) in RCA: 143] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Cytolethal distending toxin (CDT) is a bacterial toxin that initiates a eukaryotic cell cycle block at the G2 stage prior to mitosis. CDT is produced by a number of bacterial pathogens including: Campylobacter species, Escherichia coli, Salmonella enterica serovar Typhi, Shigella dystenteriae, enterohepatic Helicobacter species, Actinobacillus actinomycetemcomitans (the cause of aggressive periodontitis), and Haemophilus ducreyi (the cause of chancroid). The functional toxin is composed of three proteins; CdtB potentiates a cascade leading to cell cycle block, and CdtA and CdtC function as dimeric subunits, which bind CdtB and delivers it to the mammalian cell interior. Once inside the cell, CdtB enters the nucleus and exhibits a DNase I-like activity that results in DNA double-strand breaks. The eukaryotic cell responds to the DNA double-strand breaks by initiating a regulatory cascade that results in cell cycle arrest, cellular distension, and cell death. Mutations in CdtABC that cause any of the three subunits to lose function prevent the bacterial cell from inducing cytotoxicity. The result of CDT activity can differ somewhat depending on the eukaryotic cell types affected. Epithelial cells, endothelial cells, and keratinocytes undergo G2 cell cycle arrest, cellular distension, and death; fibroblasts undergo G1 and G2 arrest, cellular distension, and death; and immune cells undergo G2 arrest followed by apoptosis. CDT contributes to pathogenesis by inhibiting both cellular and humoral immunity via apoptosis of immune response cells, and by generating necrosis of epithelial-type cells and fibroblasts involved in the repair of lesions produced by pathogens resulting in slow healing and production of disease symptoms. Thus, CDT may function as a virulence factor in pathogens that produce the toxin.
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Affiliation(s)
- James L Smith
- Microbial Food Safety Research Unit, U.S. Department of Agriculture, Agricultural Research Service, Eastern Regional Research Center, Wyndmoor, Pennsylvania 19083, USA.
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Nakashima T, Kato Y, Yamaguchi K, Oda T. Evaluation of the anti-Trichophyton activity of a prodigiosin analogue produced by gamma-proteobacterium, using stratum corneum epidermis of the Yucatan micropig. J Infect Chemother 2005; 11:123-8. [PMID: 15990975 DOI: 10.1007/s10156-005-0376-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2004] [Accepted: 02/15/2005] [Indexed: 10/25/2022]
Abstract
Prodigiosins (PGs) are known to be a family of natural red pigments, characterized by a common pyrrolydipyrrolylmethane skeleton structure with a C-4 methoxy group, and some of these pigments have been isolated from some microorganisms. Members of the PG family have been reported to show several biological activities, such as immunosuppressive and cytotoxic activities. Recently, we discovered a bacterial strain (MS-02-063), from our microbial library, that produces large amounts of a PG analogue (PG-L-1). In this study, we examined the anti-Trichophyton activity of PG-L-1 (produced by strain MS-02-063) against clinically isolated Trichophyton spp., by a method using stratum corneum epidermis (SCE) of the Yucatan micropig, which is suitable for estimating the antifungal activity of drugs in vitro. In the National Committee for Clinical Laboratory Standards (NCCLS) method, PG-L-1 showed potent antifungal activity against nine clinically isolated strains of Trichophyton spp., although the minimum inhibitory concentration (MIC) values were slightly higher than those of bifonazole. In spite of the lower efficiency of PG-L-1 transfer into SCE from medium than that of bifonazole, PG-L-1 transferred into SCE showed more potent antifungal activity than bifonazole, at lower concentrations.
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Affiliation(s)
- Takuji Nakashima
- Division of Biochemistry, Faculty of Fisheries, Nagasaki University, Nagasaki, Japan.
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Abstract
The cytolethal distending toxins (CDTs) constitute the most recently discovered family of bacterial protein toxins. CDTs are unique among bacterial toxins as they have the ability to induce DNA double strand breaks (DSBs) in both proliferating and nonproliferating cells, thereby causing irreversible cell cycle arrest or death of the target cells. CDTs are encoded by three linked genes ( cdtA, cdtB and cdtC) which have been identified among a variety of Gram-negative pathogenic bacteria. All three of these gene products are required to constitute the fully active holotoxin, and this is in agreement with the recently determined crystal structure of CDT. The CdtB component has functional homology with mammalian deoxyribonuclease I (DNase I). Mutation of the conserved sites necessary for this catalytic activity prevents the induction of DSBs as well as all subsequent intoxication responses of target cells. CDT is endocytosed via clathrin-coated pits and requires an intact Golgi complex to exert the cytotoxic activity. Several issues remain to be elucidated regarding CDT biology, such as the detailed function(s) of the CdtA and CdtC subunits, the identity of the cell surface receptor(s) for CDT, the final steps in the cellular internalization pathway, and a molecular understanding of how CDT interacts with DNA. Moreover, the role of CDTs in the pathogenesis of diseases still remains unclear.
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Affiliation(s)
- M Thelestam
- Microbiology and Tumorbiology Center, Karolinska Institutet, Stockholm, Sweden.
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Osborne CS, Leitner I, Favre B, Ryder NS. Antifungal drug response in anin vitromodel of dermatophyte nail infection. Med Mycol 2004; 42:159-63. [PMID: 15124869 DOI: 10.1080/13693780310001656803] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Despite terbinafine being fungicidal against Trichophyton rubrum in standard NCCLS assays and rapidly accumulating in nails in vivo, onychomycosis patients require prolonged terbinafine treatment to be cured. To investigate this, we developed a more clinically relevant onychomycosis in vitro test model. Human nail powder inoculated with T. rubrum and incubated in liquid RPMI 1640 salt medium, which did not support growth alone, developed extensive and invasive mycelial growth. Antifungal drugs were added at different concentrations and cultures incubated for 1 to 4 weeks. Fungal survival was determined by spreading cultures on PDA plates without drug and measuring CFU after 1 to 4 weeks incubation. Drug activity was expressed as the nail minimum fungicidal concentration (Nail-MFC) required for 99.9% elimination of viable fungus. Terbinafine Nail-MFC was 4 microg/ml after 1 week exposure, decreasing to 1 microg/ml after 4 weeks exposure, much higher than MFCs < or = 0.03 microg/ml determined in standard NCCLS MIC assays. In contrast, other clinically used drugs were unable to kill T. rubrum after 4 weeks incubation in this model. Invasive mycelial growth on nail appears to protect T. rubrum from the cidal action of systemic drugs, thus providing a rationale for the long treatment periods in onychomycosis.
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Affiliation(s)
- C S Osborne
- Infectious Diseases Department, Novartis Research Institute, Vienna, Austria.
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Sobieszczańska BM, Osek J. Enteroaggregative and cell-detachingEscherichia coli strains among polish children with and without diarrhea. Folia Microbiol (Praha) 2003; 48:823-8. [PMID: 15058198 DOI: 10.1007/bf02931520] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
To determine the association of enteroaggregative (EAEC) and cell-detaching (CDEC) Escherichia coli with diarrhea of unknown origin among children from Wrocław (Poland), E. coli strains isolated from stool specimens of children with diarrhea were examined for mannose-resistant adherence to HEp-2 cells. EAEC were isolated from 10 of 39 (26%) children examined with diarrhea and 4 of 20 (20%) age-matched controls. CDEC were present in 14 (36%) cases of diarrhea and 7 (35%) healthy subjects. Cell-detaching activity was distinctly associated with hemolysin production. Among hemolytic CDEC strains cytotoxic necrotizing factor 1 (CNF1) synthesis prevailed among isolates obtained from cases of diarrhea (57%) in comparison with isolates obtained from healthy controls (14.3%). Although neither EAEC nor CDEC E. coli strains were associated with diarrhea of children in this setting, there were differences among EAEC and CDEC strains isolated from children with and without diarrhea.
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Affiliation(s)
- B M Sobieszczańska
- Department of Microbiology, University of Medicine, 50-368 Wrocław, Poland.
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Shehabi AA, Bulos NK, Hajjaj KG. Characterization of diarrhoeagenic Escherichia coli isolates in Jordanian children. SCANDINAVIAN JOURNAL OF INFECTIOUS DISEASES 2003; 35:368-71. [PMID: 12953946 DOI: 10.1080/003655403100009086] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
In a prospective study carried out among Jordanian children in Amman, a total of 73/250 (29.2%) stool specimens were positive for 1 or more diarrhoeagenic Escherichia coli strains using a multiplex polymerase chain reaction method. This study indicated that diarrhoeagenic E. coli isolates were found frequently more in stools of children with diarrhoea (34%) than without diarrhoea (23.1%), but without any significant difference (p > 0.05). The predominant diarrhoeagenic E. coli strains associated with diarrhoea were enteropathogenic E. coli (11.3%), followed by enterotoxigenic E. coli (9.8%) and enteroaggrative E. coli (9%), whereas in the control group these were 4.3%, 11.1% and 6%, respectively. Enteroinvasive E. coli strains (2.9%) were found only in stools of children with diarrhoea. This study revealed the absence of enterohaemorrhagic E. coli in both diarrhoeal and control stools, and found that diarrhoeagenic E. coli isolates were highly resistance to tetracycline (55%), co-trimoxazole (60%) and ampicillin (89%), which are commonly used antibiotics in Jordan.
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Affiliation(s)
- Asem A Shehabi
- Department of Pathology/Microbiology, Faculty of Medicine, Jordan University Hospital, Amman, Jordan.
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Nakashima T, Nozawa A, Majima T. A novel method using micropig stratum corneum in vitro for the evaluation of anti-Trichophyton mentagrophytes activity. Microbiol Immunol 2003; 46:521-5. [PMID: 12363015 DOI: 10.1111/j.1348-0421.2002.tb02729.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Antifungal susceptibility testing under conditions close to clinical status is expected to provide more helpful information than that obtained by a conventional microdilution method. For this purpose, we developed a novel method to evaluate anti-Trichophyton mentagrophytes activity of antifungal agents in vitro by using disks of micropig stratum corneum epidermis (SCE). Basal agar medium containing K2HPO4, MgSO4, CaCl2 and three kinds of antibiotics. Bifonazole (BFZ), lanoconazole (LCZ) or terbinafine (TBF) was added to the basal agar medium to give serially doubling dilutions ranging from 0.0006 to 10 microg/ml. Five-hundred-microl portions of the agar media thus prepared were solidified in wells of flat-bottomed plates. SCE disks (6 mm in diameter) were placed on surfaces of the agar medium and 10(4) conidia of T. mentagrophytes were inoculated on each SCE disk. There was very good correlation between the initial concentration of the antifungal agents added to the basal agar medium (microg/ml) and the concentration of the agents impregnated into the SCE disks (microg/g) (r2>0.99). The minimum inhibitory concentration (MIC) values of BFZ, LCZ and TBF were respectively 26-, 10- and 78-times higher than those measured by the standard microdilution method. From the correlation between the concentration of the agents in the basal medium and that in the SCE disks, the above MIC values corresponded to the concentrations in SCE disks (microg/g), 832.95 for BFZ, 1.42 for LCZ and 8.87 for TBF. This novel method of antidermatophytic susceptibility testing using SCE would be useful as an in vitro screening of proper antimycotics for topical treatment of dermatophytosis.
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Affiliation(s)
- Takuji Nakashima
- Pharmaceutical R&D Laboratories, POLA Chemical Industries, Inc, Yokohama, Kanagawa, Japan.
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Khan MA, Steiner TS. Mechanisms of Emerging Diarrheagenic Escherichia coli Infection. Curr Infect Dis Rep 2002; 4:112-117. [PMID: 11927041 DOI: 10.1007/s11908-002-0050-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Diarrheagenic Escherichia coli organisms are major causes of morbidity and mortality worldwide. Although most strains of E. coli are harmless commensals, a few types have emerged that are capable of disrupting the normal physiology of the human gut, producing illness ranging from watery diarrhea to fatal hemorrhagic colitis. Diarrheagenic E. coli cause infection by a variety of complex mechanisms, some of which are incompletely understood. These include adherence, elaboration of toxigenic mediators, invasion of the intestinal mucosa, and transportation of bacterial proteins into the host cells. Specific components of the host-microbial interaction that cause damage have been identified, increasing our understanding of the mechanisms of diarrhea. This article reviews some of the recent findings about the pathogenesis and infectious processes involved in three emerging pathotypes of this fascinating gram-negative bacterium.
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Affiliation(s)
- Mohammed A. Khan
- Room D458, Heather Pavilion, 2733 Heather Street, Vancouver, BC V5Z 3J5, Canada.
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Barchiesi F, Arzeni D, Camiletti V, Simonetti O, Cellini A, Offidani AM, Scalise G. In vitro activity of posaconazole against clinical isolates of dermatophytes. J Clin Microbiol 2001; 39:4208-9. [PMID: 11682563 PMCID: PMC88520 DOI: 10.1128/jcm.39.11.4208-4209.2001] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A broth macrodilution method following the recommendations established by the National Committee for Clinical Laboratory Standards was used to compare the in vitro activity of posaconazole (PCZ) with that of itraconazole (ITC) against 30 clinical isolates of dermatophytes belonging to six different species. In terms of MICs, PCZ showed an activity equal to that of ITC. MICs of PCZ at which 50% (MIC(50)) and 90% (MIC(90)) of the isolates were inhibited were 0.5 and > 4.0 microg/ml, respectively. The MIC(50) and MIC(90) of ITC were 1.0 and > 4.0 microg/ml, respectively. However, PCZ showed a more potent fungicidal activity than that of ITC against isolates belonging to the genus Microsporum (P = 0.03). PCZ merits further investigation as a potentially useful agent for treatment of dermatophytosis.
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Affiliation(s)
- F Barchiesi
- Istituto di Malattie Infettive e Medicina Pubblica, Università degli Studi di Ancona, Ancona, Italy.
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Okeke CN, Tsuboi R, Ogawa H. Quantification of Candida albicans actin mRNA by the LightCycler system as a means of assessing viability in a model of cutaneous candidiasis. J Clin Microbiol 2001; 39:3491-4. [PMID: 11574561 PMCID: PMC88377 DOI: 10.1128/jcm.39.10.3491-3494.2001] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The LightCycler system (two-step reverse transcription-PCR-fluorescent hybridization [LC RT-PCR-FH]) was used to quantify Candida albicans actin mRNA as a means of assessing its viability in a reconstituted skin model of cutaneous candidiasis following the application of an antimycotic. A 192-bp ACT exon fragment was ligated into the pCR2.1 plasmid vector, and dilutions of the cloned insert (pACT; 4.092 kb) were used as the standard reference template. The LC RT-PCR-FH system could detect 1 fg of pACT, equivalent to 2.2 copies of the plasmid. The ACT exon-based PCR primers and FH probes were C. albicans specific, and electrophoretic analysis of the LC RT-PCR-FH assay product showed a 174-bp band in agarose gel. The number of copies of C. albicans ACT mRNA per milligram of tissue decreased with increasing amounts of amorolfine applied to a C. albicans-infected skin model, showing a reduction in viability. Detection and quantification of ACT mRNA in tissue by the LC RT-PCR-FH assay corresponded with cultural isolation of C. albicans from samples. The ACT mRNA-targeted LC RT-PCR-FH assay represents a sensitive, specific, rapid, and quantitative means of assessing the viability of C. albicans in infected tissue. This method may also be useful in evaluating the therapeutic efficacies of antifungal drugs in the treatment of various forms of candidiasis and other fungal diseases.
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Affiliation(s)
- C N Okeke
- Department of Dermatology, Juntendo University School of Medicine, 2-1-1 Hongo, Bunko-ku, Tokyo 113, Japan
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Hossain MA, Ghannoum MA. New developments in chemotherapy for non-invasive fungal infections. Expert Opin Investig Drugs 2001; 10:1501-11. [PMID: 11772265 DOI: 10.1517/13543784.10.8.1501] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Dermatomycosis and subcutaneous mycosis comprise the non-invasive fungal infections commonly encountered in clinical practice around the world. The limited activity of early topical antifungal agents prompted the development of more effective systemic agents. While griseofulvin has been used for more than four decades, the use of early azoles, such as ketoconazole have resulted in better patient compliance and thus greater success. However, poor response and recurrence in dermatomycosis, as well as toxicity associated with ketoconazole therapy, has led to the search for newer antifungal agents and more effective treatment strategies. Terbinafine, itraconazole and fluconazole have the advantage of non-toxicity and a broad spectrum of activity. An overview of non-invasive fungal infections, antifungal agents in clinical use and recent developments in antifungal therapy is reviewed in this article.
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Affiliation(s)
- M A Hossain
- Center for Medical Mycology, Department of Dermatology, Case Western Reserve University and University Hospitals of Cleveland, 11100 Euclid Avenue, Cleveland, Ohio 44106-5028, USA
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Rowe MT, Kirk RB. Cross-protection phenomenon in Escherichia coli strains harbouring cytotoxic necrotizing factors and cytolethal distending toxins. Lett Appl Microbiol 2001; 32:67-70. [PMID: 11169045 DOI: 10.1046/j.1472-765x.2001.00856.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Micro-organisms which are subjected to non-lethal stress can exhibit significantly greater resistance when both the same or an unrelated stress is subsequently reapplied. This latter phenomenon is termed 'cross-protection'. In experiments using three strains of Escherichia coli harbouring cytotoxic necrotizing factor 1 and/or cytolethal distending toxin all three exhibited significantly greater (P < 0.05) resistance to salt (20% w/v) or heat (56 degrees C for up to 75 min) when prestressed with lactic acid (pH 4). This work indicates that the cross-protection phenomenon should be taken into account when devising food process operations designed to minimize the risk posed by these pathogens.
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Affiliation(s)
- M T Rowe
- Food Microbiology, Food Science Department, The Queen's University of Belfast, Belfast, Northern Ireland.
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