Annals of tropical medicine and parasitology最新文献

{"title":"Distribution of Taenia saginata metacestodes: a comparison of routine meat inspection and carcase dissection results in experimentally infected calves.","authors":"V E Soares,&nbsp;M A De Andrade Belo,&nbsp;P C B Rezende,&nbsp;V T Soccol,&nbsp;R T Fukuda,&nbsp;G P De Ooliveira,&nbsp;A J Da Costa","doi":"10.1179/1364859411Y.0000000028","DOIUrl":"https://doi.org/10.1179/1364859411Y.0000000028","url":null,"abstract":"<p><p>A comparison of techniques for detecting the presence of Cysticercus bovis in bovine carcasses was made by using carcass dissection and routine beef inspection guidelines. In the study, 28 calves were used after they were tested and found to be negative for the presence of anti-C. bovis serum antibodies and were inoculated orally with aliquots containing 6×10(4) Taenia saginata eggs. One hundred and twenty days after inoculation, the animals were slaughtered and a post mortem evaluation was done following Brazilian Federal Beef Inspection guidelines. This routine meat inspection was able to identify 71·42% of the assessed infected carcasses as being parasitized. This result implies that 28·58% of the infected carcasses would have been released as fit for human consumption since they would have been considered as free of C. bovis infection when using this method for carcass assessment. Only 3·07% of the total 2311 metacestodes present in the carcasses were identified by the conventional procedures of sanitary inspection. The assessment of different parts of the carcasses showed high infestation rates in shoulder clod (14·37%), head (11·21%), neck+chuck roll (8·05%), heart (7·75%) and top (inside) round (7·18%) which, together, were responsible for housing 48·51% of all the cysts found in the 24 beef cuts assessed. These numbers contrasted to the low incidence of cysts found in organs such as tongue (3·12%), diaphragm (1·69%) and esophagus (1·60%) which are usually described as predilection sites for the parasite.</p>","PeriodicalId":8019,"journal":{"name":"Annals of tropical medicine and parasitology","volume":"105 5","pages":"393-401"},"PeriodicalIF":0.0,"publicationDate":"2011-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1179/1364859411Y.0000000028","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"30151876","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Epidemiological characteristics and molecular typing of Salmonella enterica serovar Typhi during a waterborne outbreak in Eastern Anatolia.","authors":"Y Bayram,&nbsp;H Güdücüoğlu,&nbsp;B Otlu,&nbsp;C Aypak,&nbsp;N C Gürsoy,&nbsp;H Uluç,&nbsp;M Berktaş","doi":"10.1179/1364859411Y.0000000024","DOIUrl":"https://doi.org/10.1179/1364859411Y.0000000024","url":null,"abstract":"<p><p>In this study, we aimed to study the molecular and epidemiological characteristics of Salmonella enterica serovar Typhi (S. Typhi) outbreak in Eastern Anatolia. Six hundred and thirty-seven patients from the same county with clinical diagnosis of typhoid fever were investigated with conventional methods from stool, urine and blood specimens. Antibiotic susceptibility tests and identifications were performed for positive specimens. Clonal relationships between the isolates were investigated using pulsed field gel electrophoresis (PFGE) method. A questionnaire was completed for the water consumption habits of patients. Of 91 culture positive specimens, 76 were blood, 13 were stool and 2 were urine. The isolates were resistant to ampicillin, ampicillin/sulbactam, chloramphenicol, cefuroxime, amikacin, gentamicin and trimethoprim-sulfamethoxazole. Although there was a single band difference in some isolates, PFGE results indicated that this was an outbreak caused by single strain according to the Tenover criteria. This outbreak thought to be associated with the consumption of tap water contaminated with sewage represents a breakdown of the basic public health and civil engineering infrastructure. Appropriate public health measures should be taken in order to avoid such outbreaks in the future.</p>","PeriodicalId":8019,"journal":{"name":"Annals of tropical medicine and parasitology","volume":"105 5","pages":"359-65"},"PeriodicalIF":0.0,"publicationDate":"2011-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1179/1364859411Y.0000000024","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"30151085","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A guide to the Simulium damnosum complex (Diptera: Simuliidae) in Nigeria, with a cytotaxonomic key for the identification of the sibling species.","authors":"R J Post,&nbsp;E Onyenwe,&nbsp;S A E Somiari,&nbsp;H B Mafuyai,&nbsp;J L Crainey,&nbsp;P O Ubachukwu","doi":"10.1179/136485911X12987676649700","DOIUrl":"https://doi.org/10.1179/136485911X12987676649700","url":null,"abstract":"<p><p>Although approximately 40% of all the people blinded by Onchocerca volvulus are Nigerians, almost nothing was known about the various cytospecies of the blackfly vectors present in Nigeria until 1981. The activation of the Nigerian National Onchocerciasis Control Programme in 1986 (and that programme's initiation of mass distributions of ivermectin in 1991) provided a significant stimulus to understand the biology of the Nigerian vectors but the exploration of any possible differences between the cytospecies has been hampered by a lack of accessible taxonomic information. This review attempts to satisfy that need. There are nine different cytoforms reliably recorded from Nigeria (Simulium damnosum s.s. Nile form, S. damnosum s.s. Volta form, S. sirbanum Sirba form, S. sirbanum Sudanense form, S. soubrense Beffa form, S. squamosum A, S. squamosum B, S. squamosum C and S. yahense typical form), and three more are known from surrounding countries and might be reasonably expected to occur in Nigeria. All of these cytospecies are presumed to be vectors, although there have been almost no identifications of the vectors of O. volvulus in Nigeria. The biogeographical distribution of the cytoforms is broadly similar to that known in other parts of West Africa (although many of the cytoforms remain insufficiently studied). The physico-chemical hydrology of the Nigerian breeding sites of the cytospecies does not, however, correspond to that seen elsewhere in West Africa, and it is not clear whether this might be related to differences in the cytoforms. An illustrated cytotaxonomic key is presented to facilitate and encourage future studies.</p>","PeriodicalId":8019,"journal":{"name":"Annals of tropical medicine and parasitology","volume":"105 4","pages":"277-97"},"PeriodicalIF":0.0,"publicationDate":"2011-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1179/136485911X12987676649700","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"30101981","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"High prevalences of infection with Giardia intestinalis genotype B among children in urban and rural areas of Argentina.","authors":"N Molina,&nbsp;M Minvielle,&nbsp;S Grenóvero,&nbsp;C Salomón,&nbsp;J Basualdo","doi":"10.1179/136485911X12987676649665","DOIUrl":"https://doi.org/10.1179/136485911X12987676649665","url":null,"abstract":"<p><p>The protozoan parasite most frequently associated with diarrhoea worldwide is Giardia intestinalis. In 2005, a study was initiated to identify the genotypes of this parasite infecting children in the Argentinian provinces of Buenos Aires, Mendoza and Chaco, and to explore the associations between the genotype detected in a child, the characteristics of the child's household and the child's clinical presentation. Overall, 998 children (504 boys and 494 girls) aged between 2-14 years, with or without symptoms, were enrolled. The G. intestinalis in 94 of the 117 stool samples found positive for the parasite by microscopy were successfully genotyped by PCR. Seventy-seven of the children were found to be infected with genotype B only and 14 with genotype AII only, three children being found to have mixed (AII and B) infections. Only genotype B was detected in children from rural areas (P<0·05) and most Giardia detected in children from households with a piped water supply were also of this genotype (P<0·05). The other household characteristics investigated (quality of building, history of flooding, type of sanitation, level of overcrowding, and presence/absence of pet dogs) had no significant effect on the genotype distribution. Children infected with genotype AII were significantly younger than those infected with genotype B (P<0·05) and there was a significant positive association between infection with genotype B and abdominal pain (P<0·05). Diarrhoea was not, however, found to be significantly associated with genotype-AII or genotype-B infection. This is the first published report on the Giardia genotypes circulating in the provinces of Mendoza and Chaco. The results indicate the importance of asymptomatic children in the transmission of Giardia among the young.</p>","PeriodicalId":8019,"journal":{"name":"Annals of tropical medicine and parasitology","volume":"105 4","pages":"299-309"},"PeriodicalIF":0.0,"publicationDate":"2011-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1179/136485911X12987676649665","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"30101982","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The PCR-based detection of Leishmania major in Mus musculus and other rodents caught in southern Iran: a guide to sample selection.","authors":"M Parhizkari,&nbsp;M H Motazedian,&nbsp;Q Asqari,&nbsp;D Mehrabani","doi":"10.1179/136485911X12987676649827","DOIUrl":"https://doi.org/10.1179/136485911X12987676649827","url":null,"abstract":"In recent years, rural cutaneous leishmaniasis (CL) has become one of the most challenging public-health problems in several countries. Rodents play an important role as the ‘reservoir’ hosts of the parasite (Leishmania major) that causes the vast majority of the CL found in rural Iran. The present study deals with the role of rodents in the epidemiology of CL in Fars province, in the south of Iran, where the incidence of the disease has doubled over the last decade. Samples, of skin, foot pads, ears, livers and spleens, were collected from 89 rodents (three Meriones persicus, one Me. libycus, 64 Tatera indica and 21 Mus musculus), that had been caught in an endemic area, killed, and fixed in formalin [5% (w/v) formaldehyde]. When each sample was checked for L. major DNA by PCR, at least one sample from each of three (100%) of the Me. persicus, 35 (54·7%) of the T. indica and nine (42·9%) of the Mu. musculus was found to contain L. major DNA. Only 60% of the ear samples, 56% of the footpad samples, 38% of the liver samples and 38% of the spleen samples from the PCR-positive rodents were, however, found PCR-positive. Four of the rodents (two T. indica and two Mu. musculus) were each found to have PCR-positive ear and footpad samples but PCR-negative liver and spleen samples. Only four of the rodents (all T. indica) had PCR-positive spleen and/or liver samples but PCR-negative ear and footpad samples. It is therefore recommended that, for the PCR-based detection of L. major in Iranian rodents, priority is given to the collection and investigation of both ear and footpad samples. \u0000 \u0000Zoonotic cutaneous leishmaniasis (CL) caused by Leishmania major is now endemic in 14 of the 29 provinces of Iran, with many rural foci in the north, east and south of the country (Yaghoobi–Ershadi et al., 2005). Several species of rodents have been identified as ‘reservoir’ hosts for the causative parasite in Iran, including Meriones libycus, Me. hurrianae, Nosokia indica, Rhombomys opimus, Tatera indica and Rattus norvegicus. (Seyedi–Rashti and Nadim, 1967; Nadim and Faghih, 1968; Seyedi–Rashti and Salehzadeh, 1990; Javadian et al., 1998; Motazedian et al., 2010). Unfortunately, because L. major may cause no or only minor skin lesions in such hosts, it is not always easy to detect the infections in wild rodents (WHO, 1990; Moemenbellah–Fard et al., 2003). Most infected rodents have been identified by the collection of skin scrapings from ears or feet and the culture of these samples (Edrissian et al., 1982). PCR has, however, already been found useful for the identification of possible reservoir hosts, without the need for culture and parasite isolation (Alexander et al., 1998; Oliveira et al., 2005; Brandao–Filho and Shaw, 2006). \u0000 \u0000The main aim of the present study was to use a PCR-based assay and ear, footpad, liver and spleen samples to explore the prevalences of leishmanial infection among rodents that had been trapped in various parts of Fars province, in souther","PeriodicalId":8019,"journal":{"name":"Annals of tropical medicine and parasitology","volume":"105 4","pages":"319-23"},"PeriodicalIF":0.0,"publicationDate":"2011-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1179/136485911X12987676649827","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"30101984","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Changes in the distribution of human schistosomiasis in Far North province, Cameroon, since 1986.","authors":"D Massenet,&nbsp;A Toukour,&nbsp;R I Kamwa Ngassam,&nbsp;R Djao,&nbsp;J-L Portal,&nbsp;L-A Tchuem Tchuenté","doi":"10.1179/136485911X12987676649746","DOIUrl":"https://doi.org/10.1179/136485911X12987676649746","url":null,"abstract":"The most recent, large-scale survey on human urinary schistosomiasis (caused by Schistosoma haematobium) and human intestinal schistosomiasis (caused by S. mansoni) in Cameroon, which was carried out in 1986, revealed that both diseases were endemic throughout Far North province (Ratard et al., 1990). In a survey in 2008–2009, Massenet et al. (2009) found that the prevalences of these diseases in the neighbouring North province were markedly lower than those recorded by Ratard et al. (1990), in the same area, about two decades earlier. Since antischistosomal treatment has never been delivered at community level in North province, the reasons behind this favourable trend were (and remain) unclear. The aim of the present, cross-sectional survey, conducted in 25 primary schools in 2009, was to see if urinary schistosomiasis and intestinal schistosomiasis had shown a similar decline in Far North province, from the prevalences of 35% and 9%, respectively, recorded among schoolchildren in 1986 (Ratard et al., 1990). Lot quality assurance sampling (LQAS) was used, previous studies having shown this to be a cost-effective method of identifying communities that qualify for treatment (Rabarijaona et al., 2003; Brooker et al., 2005). \u0000 \u0000The 25 surveyed schools (see Figure) were those previously investigated, in 1986, by Ratard et al., (1990). In each school, eight boys and seven girls were randomly selected from an exhaustive list of the children aged 9–11 years who were present on the day of the survey. Human infection with S. mansoni or S. haematobium is considered hyper-endemic in a community when eggs are observed in at least 50% of stool or urine samples, respectively. In each study school, for each of these schistosome species, the null hypothesis (H0) that the prevalence of infection was ⩾50% among all the schoolchildren was therefore explored. Using the LQAS method, the null hypothesis was accepted if at least four of the 15 children investigated were observed to be excreting the eggs of the schistosome of interest (this sampling plan gives a 95% probability of the null hypothesis being accepted when the prevalence is ⩾50%, as well as an 80% probability of schistosomiasis being categorized as not hyper-endemic in a school where the prevalence of infection is <20%). \u0000 \u0000 \u0000 \u0000The locations of the schools surveyed in the Logone et Chari (1), Mayo Danay (2), Kaele (3), Diamare (4), Mayo Sawa (5) and Mayo Tsanaga (6) departments of Far North province in 2009, showing the schools where Schistosoma haematobium was ... \u0000 \u0000 \u0000 \u0000Each subject was given a stool container (including a specimen-collection spoon) and a urine container and asked to collect fresh stool and urine specimens between 10·00 and 15·00 hours. On the day of their collection, the stool specimens were checked for S. mansoni eggs as Kato–Katz smears (Katz et al., 1972) while 10 ml of each urine sample were checked for S. haematobium eggs, by membrane filtration (WHO, 1985). \u0000 \u0000The locations of th","PeriodicalId":8019,"journal":{"name":"Annals of tropical medicine and parasitology","volume":"105 4","pages":"325-8"},"PeriodicalIF":0.0,"publicationDate":"2011-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1179/136485911X12987676649746","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"30101985","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Strongyloidiasis presenting as eosinophilic ascites.","authors":"S Jariwala,&nbsp;Y Langman,&nbsp;A A Benson,&nbsp;E Wolf,&nbsp;J Moss,&nbsp;C C Zhu,&nbsp;L Brandt","doi":"10.1179/136485911X12987676649863","DOIUrl":"https://doi.org/10.1179/136485911X12987676649863","url":null,"abstract":"Approximately 30 million people are thought to harbour Strongyloides stercoralis, a parasitic nematode that is endemic in Latin America, sub-Saharan Africa, South–east Asia, and south–eastern U.S.A. (Liu and Weller, 1993; Siddiqui and Berk, 2001). Although auto-infection may lead to chronic or intermittent symptoms that last several decades, even in individuals who have not recently travelled to endemic areas, human infection with this nematode is typically asymptomatic or only causes mild gastro-intestinal symptoms (Liu and Weller, 1993). In immunocompromised individuals, however, strongyloidiasis is often devastating and the cause of high mortality, with pneumonia, meningitis and Gram-negative sepsis among the life-threatening conditions that can occur as the St. stercoralis larvae migrate throughout the body. An unusual case of strongyloidiasis in a young, otherwise healthy patient, who presented (in New York, NY) with dysphagia, episodes of diarrhoea alternating with constipation, and increasing abdominal girth (all of which resolved following treatment) is described and discussed below.","PeriodicalId":8019,"journal":{"name":"Annals of tropical medicine and parasitology","volume":"105 4","pages":"335-8"},"PeriodicalIF":0.0,"publicationDate":"2011-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1179/136485911X12987676649863","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"30101987","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Dihydroartemisinin-praziquantel combinations and multiple doses of dihydroartemisinin in the treatment of Schistosoma japonicum in experimentally infected mice.","authors":"H-J Li, W Wang, Y-H Tao, G-L Qu, Y-T Xing, Y-Z Li, J-Y Wei, J-R Dai, Y-S Liang","doi":"10.1179/136485911X13018982159979","DOIUrl":"10.1179/136485911X13018982159979","url":null,"abstract":"","PeriodicalId":8019,"journal":{"name":"Annals of tropical medicine and parasitology","volume":"105 4","pages":"329-33"},"PeriodicalIF":0.0,"publicationDate":"2011-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4090795/pdf/atm-105-04-329.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"30101986","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A dot-ELISA using a partially purified cathepsin-L-like protein fraction from Taenia solium cysticerci, for the diagnosis of human neurocysticercosis.","authors":"R Piña,&nbsp;A H Gutiérrez,&nbsp;R H Gilman,&nbsp;D Rueda,&nbsp;C Sifuentes,&nbsp;M Flores,&nbsp;P Sheen,&nbsp;S Rodriguez,&nbsp;H H García,&nbsp;M Zimic","doi":"10.1179/136485911X12987676649782","DOIUrl":"https://doi.org/10.1179/136485911X12987676649782","url":null,"abstract":"<p><p>Human neurocysticercosis (NCC), caused by the cestode Taenia solium, is responsible for a significant amount of neurological morbidity and epilepsy in developing countries. The disease remains highly endemic in many areas, despite several efforts and interventions to control it. A simple, cheap and fast diagnostic assay that is suitable for use in field conditions is highly desired. In immunodiagnostics based on western immunoblots or standard ELISA, a cathepsin-L-like protein purified from the cysticercus fluid has previously performed well as an antigen. In a recent study in Peru, the same 53/25-kDa antigen was therefore used in the development of a dot-ELISA that could be employed for mass screenings under field conditions. The assay was standardized and tested not only against sera from a large group of NCC cases but also against sera from patients with other common parasitic infections, so that sensitivity and specificity could be assessed. For NCC, the assay gave better sensitivity in the detection of individuals with extraparenchymal cysts (94·4%-100%) or multiple parenchymal cysts (74·6%-80·0%) than in the detection of individuals with single parenchymal cysts (29·4%-45·1%). The assay also showed a high specificity for NCC (99·0%-100%), with a very low level of cross-reactivity with other parasitic infections. The dot-ELISA developed in this study is a highly specific, simple, cheap and rapid test for NCC that could be used under field conditions, even in the low-resource settings that are common in developing countries.</p>","PeriodicalId":8019,"journal":{"name":"Annals of tropical medicine and parasitology","volume":"105 4","pages":"311-8"},"PeriodicalIF":0.0,"publicationDate":"2011-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1179/136485911X12987676649782","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"30101983","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Characterisation of the genes encoding resistance to metronidazole (rdxA and frxA) and clarithromycin (the 23S-rRNA genes) in South African isolates of Helicobacter pylori.","authors":"N F Tanih,&nbsp;L M Ndip,&nbsp;R N Ndip","doi":"10.1179/136485911X12899838683485","DOIUrl":"https://doi.org/10.1179/136485911X12899838683485","url":null,"abstract":"<p><p>Helicobacter pylori has been incriminated in human diseases, such as peptic ulcer, gastritis and gastric malignancy. Although modern triple-drug regimens are usually highly effective in the treatment of H. pylori infection, the emergence of resistance to two of the most used antibiotics, metronidazole (Mtz) and clarithromycin (Cla), is a serious and increasing problem. Truncations in the rdxA and frxA genes of H. pylori are thought to be associated with Mtz resistance whereas mutations in the pathogen's 23S-ribosomal-RNA (23S-rRNA) genes are associated with Cla resistance. In a recent study, PCR and sequence analysis of the rdxA, frxA and 23S-rRNA genes were used to explore the genetic basis of resistance to Mtz and Cla in H. pylori. When 200 isolates of H. pylori from the Eastern Cape province of South Africa were tested for antibiotic susceptibility, almost all (95·5%) were found resistant to Mtz and 20·0% were found resistant to Cla. Only the Mtz-resistant isolates showed rdxA and frxA truncation. Two point mutations were detected in the 23S-rRNA genes of the Cla-resistant isolates. Many significant changes (resulting in 13 amino-acid substitutions in nine loci and truncated proteins in 14 loci) were observed in the rdxA genes of the Mtz-resistant isolates, and it appears that, compared with the rarer changes detected in frxA, such mutations may contribute more significantly to the high prevalence of Mtz resistance. To guide empiric treatment, the genotypes and antibiotic susceptibility of H. pylori in the Eastern Cape province of South Africa need to be monitored regularly.</p>","PeriodicalId":8019,"journal":{"name":"Annals of tropical medicine and parasitology","volume":"105 3","pages":"251-9"},"PeriodicalIF":0.0,"publicationDate":"2011-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1179/136485911X12899838683485","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"29899124","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}