Metronidazole
M. Lindsay Grayson, Sara E. Cosgrove, Suzanne M. Crowe, M. Lindsay Grayson, William Hope, James S. McCarthy, John Mills, Johan W. Mouton, David L. Paterson in Kucers’ The Use of Antibiotics, 2017
The trophozoites of Entamoeba histolytica are susceptible to metronidazole, and de novo resistant strains have not been encountered outside of in vitro induction of resistance (Ravdin and Skilogiannis, 1989; Ravdin, 1995; Samarawickrema et al., 1997). Dientamoeba fragilis is also susceptible (Chan et al., 1994; Nagata et al., 2012). Blastocystis was thought to be metronidazole-susceptible, but a recent study of clinical isolates (subtype ST1, ST3, ST4, and ST8) obtained from antibiotic-untreated patients with gastrointestinal symptoms showed metronidazole MIC values from 64 to 250 µg/ml (Telalbasic et al., 1991; Haresh et al., 1999; Roberts et al., 2015). There was no significant difference in metronidazole susceptibilities among the different subtypes (Roberts et al., 2015). In another study, Blastocystis subtype 7 was resistant to metronidazole whereas subtype 4 was susceptible (Mirza et al., 2011). Metronidazole-resistant strains of Blastocystis may have reduced fitness (Wu et al., 2014).
Dientamoeba fragilis Infection
Dongyou Liu in Handbook of Foodborne Diseases, 2018
Dientamoeba fragilis is a pathogenic protozoan of the human gastrointestinal tract with a worldwide distribution.1–4 First described in 1918 by Jepps and Dobell,5–7 it has emerged as an important and misdiagnosed cause of chronic gastrointestinal illnesses such as diarrhea and “irritable-bowel-like” gastrointestinal disease.8–12 Almost a century after its observation, and although it has been described around the world, there are still doubts about its life cycle, prevalence, pathogenicity, and treatment.
Optimization of routine microscopic and molecular detection of parasitic protozoa in SAF-fixed faecal samples in Sweden
Published in Infectious Diseases, 2020
Jessica Ögren, Olaf Dienus, Andreas Matussek
G. intestinalis is the most common gastroenteritis causing protozoa in Sweden. The majority of patients with G. intestinalis are infected abroad [3]. E. histolytica infections are rare but in the past the reporting of E. histolytica has been hampered by reporting of microscopic findings of E. histolytica/E. dispar- complex as E. histolytica which has overestimated the incidence [14,15]. The use of molecular typing has decreased the over-reporting. Dientamoeba fragilis is common, but confirmation of virulence and the potential mechanisms of pathogenicity are yet to be determined [16–20]. Reported prevalence figures vary depending on methods used, patient population and location [20–23]. Trophozoites of G. intestinalis and E. histolytica are analysed either as motile in fresh samples or by staining of SAF-fixed samples, mainly only on request. The recommended method for D. fragilis is trichrome staining of fresh or SAF-fixed samples [24–26] and is usually done only on request.
Validating microscopic colitis (MC) in Swedish pathology registers
Published in Scandinavian Journal of Gastroenterology, 2018
Magnus Svensson, David Bergman, Ola Olén, Pär Myrelid, Johan Bohr, Anna Wickbom, Hamed Khalili, Andreas Münch, Jonas Halfvarson, Jonas F. Ludvigsson
Tests for gastrointestinal infections as part of the diarrhea investigation were available in 111/215 patients (52%) (Table 3). These mainly consisted of stool cultures, but were in 59 (53%) of those patients combined with test for C. difficile toxin, and in a small number also with tests for viral and parasitic infections. In three cases where microbial pathogens had been detected (Giardia lamblia; Campylobacter jejuni; and Calici virus combined with ‘parasitic infection’), MC was regarded as unlikely. One woman with a 10-month history of diarrhea and weight loss had fecal Dientamoeba fragilis combined with Blastocystis hominis four months prior to a biopsy showing LC; new stool samples 2 months prior to biopsy were negative for these parasites and we classified this case as confirmed LC.
The impact of water crises and climate changes on the transmission of protozoan parasites in Africa
Published in Pathogens and Global Health, 2018
Shahira A. Ahmed, Milena Guerrero Flórez, Panagiotis Karanis
In SSA and Asia (developing settings), the common water enteric pathogenic protozoa include G. duodenalis (intestinalis), Entamoeba spp., Cryptosporidium spp., Cyclospora cayetanensis, and Microsporidia. Whereas other species such as Blastocystis spp. and Dientamoeba fragilis are usually isolated from developed countries [13,14].
Related Knowledge Centers
- Trophozoite
- Vacuole
- Failure to Thrive
- Dientamoebiasis
- Pinworm Infection
- Diiodohydroxyquinoline
- Trichomonadida
- Biological Life Cycle
- Fecal–Oral Route
- Parasitic Worm