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Sequence diversity and linkage disequilibrium within the merozoite surface protein-1 (Msp-1) locus of Plasmodium falciparum: a longitudinal study in Brazil.

The merozoite surface protein-1 (MSP-1) is a major vaccine candidate for the asexual blood stage of malaria. We examined both the extent of sequence diversity in block 17, the 3' end of Msp-1 gene coding for a 19-kDa polypeptide (MSP-1(19)) putatively involved in red blood cell binding, and the patterns of linkage disequilibrium between polymorphic sites throughout the Msp-1 locus. The parasite population sample consisted of Plasmodium falciparum isolates collected between 1985 and 1998 in Rondĵnia, an area of hypoendemic malaria transmission in the southwestern Brazilian Amazon. Results were summarized as follows. (1) Seven block-17 sequence variants or haplotypes were found among 130 isolates, including two new haplotypes (novel combinations of previously reported amino acid replacements), here named Brazil-1 (E-TSR-F) and Brazil-2 (Q-TSR-F). (2) As previously shown for other Msp-1 polymorphisms, frequencies of block-17 haplotypes displayed significant temporal variation. (3) Extensive linkage disequilibrium was demonstrated between neighboring dimorphic sites within block 17, as well as between polymorphisms at the 5' and 3' ends of Msp-1 (map distance range: 3.83-4.99 kb). (4) The overall patterns of linkage disequilibrium within Msp-1 remained stable over a period of nearly one decade, and examples of possible 'epidemic' expansion of parasites carrying particular Msp-1 alleles were found in the 1980s and 1990s. These results are discussed in relation to the population biology of P. falciparum and the development of malaria vaccines based on MSP-1.

Alleles↗
PubMed2006

Stx genotypes and antimicrobial resistance profiles of Shiga toxin-producing Escherichia coli strains isolated from human infections, cattle and foods in Brazil.

A total of 107 Shiga toxin-producing Escherichia coli strains (STEC) isolated from different origins in São Paulo, Brazil, and belonging to different serotypes were characterized regarding stx subtypes and susceptibility to antimicrobial agents. Most of the human STEC strains harbored stx1 (85.7%), while stx2, associated or not to stx1, was identified preferentially in the animal and food strains. None of the STEC strains carried stx1c. Some genotypes occurred exclusively among strains of bovine origin as stx2c, stx1+2+2c (16.5% each), and stx2d (0.9%), whereas stx2+2c2vha) was only identified among the O157:H7 human strains. Moreover, the stx(2c2vhb) subtype was found more frequently among bovine than human strains (39% vs. 4.8%). The highest frequencies of susceptibility to antimicrobial agents were observed among bovine (87%) and food (100%) STEC strains, while 47.6% of the human isolates were resistant to at least one drug. Multiresistance occurred among O111 STEC strains from human and bovine origin. The antimicrobials to which resistance was most frequently observed were tetracycline (90%) and streptomycin (75%) among human strains, and also sulphazotrin (88%) in animal strains. A few serotypes were commonly identified among STEC strains isolated from diverse sources in Brazil, but in general the strains presented distinct stx subtypes and/or antimicrobial resistance profiles.

Animals↗
PubMed2006

Phenotypic characteristics, virulence profile and genetic relatedness of O157 Shiga toxin-producing Escherichia coli isolated in Brazil and other Latin American countries.

Thirty-eight Shiga toxin-producing Escherichia coli (STEC) O157:H7/H(-) strains isolated from human infections, cattle and foods in Brazil and in some other Latin American countries were compared with regard to several phenotypic and genotypic characteristics. The genetic relatedness of the strains was also determined by pulsed-field gel electrophoresis (PFGE). Similar biochemical behaviour was identified, regardless of the origin and country of the strains. Most (89.5%) strains were sensitive to the antimicrobial agents tested, but resistance to at least one drug was observed among bovine strains. Although a diversity of stx genotypes was identified, most (77.8%) of the human strains harboured stx(2) or stx(2)stx(2c(2vha)), whereas stx(2c(2vha)) prevailed (64.2%) among strains isolated from cattle. stx(1) and stx(1)stx(2c(2vha)) were the genotypes identified less frequently, and occurred exclusively among strains isolated from food and cattle, respectively. Despite differences in the stx genotypes, all strains carried eae-gamma, efa1, ehx, iha, lpf(O157) and toxB sequences. Many closely related subgroups (more than 80% of similarity) were identified by PFGE, and the presence of a particular O157:H7 STEC clone more related to human infections in Brazil, as well as a common origin for some strains isolated from different sources and countries in Latin America can be suggested.

Animals↗
PubMed1991

Oral mucosal health and disease in institutionalized elderly in Brazil.

During the last decade, many studies in Europe and North America have evaluated oral conditions and dental needs in the elderly. Similar information does not exist in Brazil. The aim of this study was to determine the prevalence of oral health and disease in elderly persons living in an institution in the city of Piracicaba, State of São Paulo, Brazil. Of 350 elderly persons, 134 males and 136 females were interviewed and clinically examined. Less than one half had healthy mouths. 58.9% of the examined individuals showed one or more lesions in the oral mucosa, the most frequent being denture-induced stomatitis (20.0%). Fibrous hyperplasias (11.8%) and angular cheilitis (9.3%) were fairly common. Gender, use and degree of hygiene of the denture were factors statistically significantly contributing to prevalence of denture stomatitis. Precancerous lesions such as leukoplakia (3.0%), actinic cheilitis (2.6%) were uncommon but three cases of squamous carcinoma (1.1%) were revealed. This study emphasizes the need for regular oral examinations of the elderly by personnel trained in oral diagnosis.

Aged↗
PubMed2000

A new species of Calomys (Rodentia, Sigmodontinae) from Central Brazil identified by its karyotype.

Ten species of small rodents of genus Calomys are found in South America. Three of these ten species are known to occur in Brazil: C. tener, C. laucha and C. expulsus (= C. callosus expulsus). Almost all Calomys karyotypes are made up of acrocentric pairs. In this paper we describe a new karyotype with 2n = 46 (FN = 66), including 11 meta/submetacentric and 11 acrocentric autosomal pairs. This is not related to any described Calomys karyotype. The X chromosome is a medium submetacentric and the Y is a small acrocentric. This new karyotype is briefly compared to karyotype of the sympatric species C. tener (2n = 66, FN = 66). The reduced diploid number and small amount of pericentromeric heterochromatin observed in the biarmed chromosomes that contrasts to large blocks seen in acrocentrics seem to indicate that centric fusion and loss of constitutive heterochromatin have led to the new karyotype. Cytogenetic evidence suggests strongly that a new species with 2n = 46 from Central Brazil should be described in the genus Calomys.

Animals↗
PubMed2005

Effectiveness of home-based peer counselling to promote breastfeeding in the northeast of Brazil: a randomized clinical trial.

AIMS: To evaluate the effectiveness of home-based peer counselling to increase breastfeeding rates for unfavourably low birthweight babies. METHODS: Randomized clinical trial carried out in maternity hospitals and households in Fortaleza, one of the regions in Brazil with very low income; 1003 mothers and their newborns were selected in eight maternity hospitals. Newborns needed were healthy and weighed less than 3000 g. INTERVENTION: Breastfeeding counselling, conducted by lay counsellors from the community, during home visits carried out on days 5, 15, 30, 60, 90 and 120 after birth. MAIN OUTCOME MEASURE: Feeding methods in the fourth month of life. RESULTS: The intervention increased exclusive breastfeeding (24.7% vs 19.4%; p=0.044), delayed the introduction of formula and increased the time infants substituted breastfeeding to bottle milk (bottle milk 33.4% in the control group and 20.1% in the intervention group; p=0.00002). When comparing the frequency of artificial breastfeeding versus all other forms of breastfeeding (exclusive+predominant+partial), the intervention increased breastfeeding rates in 39% (RR=0.61; CI 95%: 0.50-0.75); 15% of children were free from artificial feeding (absolute risk reduction). The number of families to be visited to avoid one child receiving artificial feeding (NNT) was 7 (CI 95%: 5-13). CONCLUSIONS: Breastfeeding counselling, promoted by lay counsellors, can impact favourably on exclusive breastfeeding rates and contribute to delaying the utilization of milk formula and weaning. The intervention has great application potential because most cities in the northeast of Brazil count on community health workers that could do the counselling.

Adult↗
PubMed2002

Fluctuations in public water fluoride level in Bauru, Brazil.

OBJECTIVES: The aim of this study was to monitor the quality of public water supply fluoridation in Bauru, in the state of São Paulo, Brazil. METHODS: Water samples collected three times a week during four weeks in 20 areas of distribution of water were supplied by the City Water Department of Bauru, São Paulo, Brazil. Fluoride was analyzed using the ion-specific electrode (Orion model 9409) after sample buffering with an equal volume of TISAB II. Data were compared to fluoride concentration reported by City Water Department. RESULTS: Fluoride content ranged between 0.01 ppm and 9.35 ppm (n = 240). There was great variation among the different areas of distribution of water, as showed by the Levene test (P < .001). Kruskal-Wallis test showed a statistically significant difference in mean fluoride concentration among different areas (P < .001). Mean fluoride concentration was less than the optimum concentration (0.8 ppm) in 89 percent of samples. The values reported by the City water Department were always higher than the analyzed fluoride concentrations. CONCLUSIONS: Based on the results from this study, more rigorous surveillance and monitoring of water fluoridation in Bauru is recommended.

Analysis of Variance↗
PubMed2006

Tooth loss in a young population from south Brazil.

OBJECTIVES: To assess the prevalence, extent, and risk indicators of tooth loss in a representative young urban population from south Brazil. METHODS: A representative sample was drawn using a multi-stage probability cluster sampling strategy, and consisted of 612 subjects 14-29 years of age in the metropolitan area of Porto Alegre, Brazil. A clinical examination was carried out by 4 calibrated examiners in a mobile examination center. RESULTS: The prevalence of tooth loss was 44.8%, 26%, and 60%, and the mean tooth loss was 1.4, 0.6, and 2.4 teeth in the age groups 14-29, 14-19 and 25-29 years, respectively. First molars were the most frequently missing teeth, and the mandibular incisors and canines were the least missing teeth. Tooth loss increased sharply with age, and was similar in males and females. Having > or =4 missing teeth was significantly associated with low socioeconomic status and heavy smoking, and was significantly more likely in persons who had > or =2 teeth with caries/fillings and/or > or =5 mm attachment loss. CONCLUSION: Tooth loss is a dental health concern in this young Brazilian population. Community-based oral diseases prevention programs targeting groups having these risk factors should be implemented to reduce tooth loss.

Adolescent↗
PubMed2005

Prevalence of Ehrlichia canis infection in thrombocytopenic dogs from Rio de Janeiro, Brazil.

BACKGROUND: Infection with Ehrlichia canis causes a highly variable, multisystemic disease in dogs. Nevertheless, many clinicians in Rio de Janeiro, Brazil, use the presence of only thrombocytopenia to make a presumptive diagnosis of E canis infection. OBJECTIVE: The objective of this study was to determine the prevalence of E canis in thrombocytopenic dogs from Rio de Janeiro, Brazil, using polymerase chain reaction (PCR). METHODS: Following DNA extraction of whole blood samples from 226 dogs, PCR assays were done using primers for rickettsial DNA (including Ehrlichia spp, Anaplasma platys and A phagocytophilum) and using E canis-specific primers (16S rRNA gene). Dogs were grouped as thrombocytopenic and nonthrombocytopenic based on platelet counts. The null hypothesis that there was no difference in the prevalence of E canis in these groups was rejected at P<.05. RESULTS: Thirty-six (32.1%) of the thrombocytopenic dogs and 4 (3.5%) of the nonthrombocytopenic dogs were positive for rickettsial gene sequences (P<.0001). Further, 30 (26.8%) of thrombocytopenic dogs and 4 (3.5%) nonthrombocytopenic dogs were positive for E canis-specific gene sequences (P<.0001). CONCLUSIONS: Although the prevalence of E canis infection was higher in thrombocytopenic dogs, less than one third of these dogs had demonstrable E canis infection. Thus, thrombocytopenia is not specific for the detection of E canis infection and should not be used solely to establish a diagnosis of canine ehrlichiosis, even in a geographic area with relatively high disease prevalence.

Animals↗
PubMed1993

[Incidence and prevalence of serotypes of enteroaggregative Escherichia coli from diarrheal patients in Brazil, Myanmar and Japan].

By using HeLa cells, we tried to detect enteroaggregative Escherichia coli from stock strains derived from infants with or without diarrhea in Brazil and Myanmer, and from diarrheal patients in Osaka, Japan. Enteroaggregative E. coli was detected from 7.9% in diarrheal cases, 5.6% in control cases in Brazil and from 5.4% in diarrheal cases, 3.4% in control cases in Myanmar. A total of 38 strains that showed aggregative adherence to HeLa cells was examined for colony hybridization with the 32P-labeled EAggEC probe. Thirty-four strains hybridized with the EAggEC probe, while 4 strains did not hybridize with the probe, suggesting an existence of another aggregative factor. Seventeen of the 38 strains were O-antigen serotypeable. Eight strains belonged to serogroups O44, O86, O111, O125 and O126, which have been considered to be enteropathogenic E. coli serogroups. Most of the 38 strains were H-antigen serotypeable.

Bacterial Adhesion↗
PubMed1993

[Serotypes of enteroadherent Escherichia coli exhibiting diffuse pattern of adherence isolated from diarrheal patients and healthy controls in Brazil, Myanmar and Japan].

We tried to detect enteroadherent Escherichia coli exhibiting a diffuse pattern of adherence to HeLa cells from stock strains derived from patients with or without diarrhea in Brazil, Myanmar and Japan (Osaka). Enteroadherent E. coli was found from 16 (23 strains) out of 126 (384 strains) in diarrheal infant cases (12.7%), 26 (29 strains) out of 126 (348 strains) in healthy control cases (20.6%) in Brazil, from 15 (18 strains) out of 221 (542 strains) in diarrheal infant cases (6.8%), 4 (4 strains) out of 87 (212 strains) in healthy control cases (4.6%) in Myanmar. In Japan (Osaka), enteroadherent E. coli was detected from 7 (7 strains) out of 123 (198 strains) in diarrheal cases (5.7%). These results show that enteroadherent E. coli (diffuse) may not be associated with diarrhea. Forty-four (62.9%) out of 70 strains belonged to 19 O serogroups or 21 O:H serotypes. All strains were H antigen serotypable, and 26 strains were found to be nonmotile. The predominant O:H serotypes were O11:H15, O11:H-, O20:H34, O21:H5, O89:H-, O99:H33 and O154:H45. Only one strain belonged to enteropathogenic E. coli serogroup O127.

Bacterial Adhesion↗
PubMed2003

Demographic threats to the sustainability of Brazil nut exploitation.

A comparative analysis of 23 populations of the Brazil nut tree (Bertholletia excelsa) across the Brazilian, Peruvian, and Bolivian Amazon shows that the history and intensity of Brazil nut exploitation are major determinants of population size structure. Populations subjected to persistent levels of harvest lack juvenile trees less than 60 centimeters in diameter at breast height; only populations with a history of either light or recent exploitation contain large numbers of juvenile trees. A harvesting model confirms that intensive exploitation levels over the past century are such that juvenile recruitment is insufficient to maintain populations over the long term. Without management, intensively harvested populations will succumb to a process of senescence and demographic collapse, threatening this cornerstone of the Amazonian extractive economy.

Bertholletia↗
PubMed1995

High frequency of strains multiply resistant to ampicillin, trimethoprim-sulfamethoxazole, streptomycin, chloramphenicol, and tetracycline isolated from patients with shigellosis in northeastern Brazil during the period 1988 to 1993.

The occurrence and antimicrobial resistance pattern of Shigella isolates obtained from persons in community and hospital-based studies of diarrhea and matched controls in northeastern Brazil were studied. The isolation rate of Shigella spp. from patients with diarrhea during 1988 to 1993 varied from 4.5% (26 of 575) for the urban community of Gonçalves Dias to 6.7% (12 of 179) and 5.9% (7 of 119) for Hospital Infantil and Hospital Universitário, respectively. Of the 55 Shigella isolates (45 from patients with diarrhea, 8 from controls, and 2 undetermined) 73% (40 of 55) were Shigella flexneri, 16% (9 of 55) were S. sonnei, 7% (4 of 55) were S. boydii, and 4% (2 of 55) were S. dysenteriae. Of 39 S. flexneri strains, over half were resistant to ampicillin, trimethoprim-sulfamethoxazole, or both. Over 64% were resistant to streptomycin, chloramphenicol, and tetracycline. Overall, 82% of all S. flexneri isolates were resistant to four or more antimicrobial agents tested. As elsewhere, in the northeast of Brazil, ampicillin and trimethoprim-sulfamethoxazole are no longer reliable for treatment of S. flexneri infection. Most Shigella strains were resistant to four or more antimicrobial agents. Nalidixic acid was still useful for treatment of infections due to S. flexneri.

Adolescent↗
PubMed2000

A novel class A extended-spectrum beta-lactamase (BES-1) in Serratia marcescens isolated in Brazil.

Serratia marcescens Rio-5, one of 18 extended-spectrum beta-lactamase (ESBL)-producing strains isolated in several hospitals in Rio de Janeiro (Brazil) in 1996 and 1997, exhibited a high level of resistance to aztreonam (MIC, 512 microgram/ml) and a distinctly higher level of resistance to cefotaxime (MIC, 64 microgram/ml) than to ceftazidime (MIC, 8 microgram/ml). The strain produced a plasmid-encoded ESBL with a pI of 7.5 whose bla gene was not related to those of other plasmid-mediated Ambler class A ESBLs. Cloning and sequencing revealed a bla gene encoding a novel class A beta-lactamase in functional group 2be, designated BES-1 (Brazil extended-spectrum beta-lactamase). This enzyme had 51% identity with chromosomal class A penicillinase of Yersinia enterocolitica Y56, which was the most closely related enzyme and 47 to 48% identity with CTX-M-type beta-lactamases, which were the most closely related ESBLs. In common with CTX-M enzymes, BES-1 exhibited high cefotaxime-hydrolyzing activity (k(cat), 425 s(-1)). However, BES-1 differed from CTX-M enzymes by its significant ceftazidime-hydrolyzing activity (k(cat), 25 s(-1)), high affinity for aztreonam (K(i), 1 microM), and lower susceptibility to tazobactam (50% inhibitory concentration [IC(50)], 0.820 microM) than to clavulanate (IC(50), 0.045 microM). Likewise, certain characteristic structural features of CTX-M enzymes, such as Phe-160, Ser-237, and Arg-276, were observed for BES-1, which, in addition, harbored different residues (Ala-104, Ser-171, Arg-220, Gly-240) and six additional residues at the end of the sequence. BES-1, therefore, may be an interesting model for further investigations of the structure-function relationships of class A ESBLs.

Amino Acid Sequence↗
PubMed2000

A novel CTX-M beta-lactamase (CTX-M-8) in cefotaxime-resistant Enterobacteriaceae isolated in Brazil.

To estimate the diversity of extended-spectrum beta-lactamases in Brazil, 18 strains from different species of the family Enterobacteriaceae exhibiting a positive double-disk synergy test were collected by a clinical laboratory from several hospitals in Rio de Janeiro, Brazil, in 1996 and 1997. Four strains (Proteus mirabilis, Enterobacter cloacae, Enterobacter aerogenes, and Citrobacter amalonaticus) hybridized with a 550-bp CTX-M probe. The P. mirabilis strain produced a CTX-M-2 enzyme. The E. cloacae, E. aerogenes, and C. amalonaticus isolates harbored a bla gene which was identified by cloning and sequencing as a bla(CTX-M) gene. E. coli HB101 transconjugants and the E. coli DH5alpha transformant harboring a recombinant plasmid produced a CTX-M beta-lactamase with an isoelectric point of 7.6 conferring a resistance phenotype characterized by a higher level of resistance to cefotaxime than to ceftazidime, as observed with the other CTX-M enzymes. The deduced protein sequence showed a novel Ambler class A CTX-M enzyme, named CTX-M-8, which had 83 to 88% identity with the previously described CTX-M enzymes. The phylogenic study of the CTX-M family including CTX-M-8 revealed four CTX-M types, CTX-M-8 being the first member of a new phylum of CTX-M enzymes. The evolutionary distances between the four types of CTX-M were large, suggesting that the four clusters branched off early from a distant unknown enzyme and that intermediate enzymes probably existed.

Amino Acid Sequence↗
PubMed2002

Antimicrobial resistance in Haemophilus influenzae isolated during population-based surveillance for meningitis in Salvador, Brazil.

Antimicrobial susceptibility was determined for 150 Haemophilus influenzae isolates obtained during population-based surveillance for meningitis in Salvador, Brazil. Ten (6.7%) isolates were resistant to ampicillin and chloramphenicol. Of these, two isolates, a beta-lactamase and non-beta-lactamase producer, were resistant to amoxacillin-clavulinic acid. These findings indicate that present antibiotic regimens in Brazil may not be appropriate for the treatment of H. influenzae meningitis.

Amoxicillin-Potassium Clavulanate Combination↗
PubMed2004

Screening and characterization of mutations in isoniazid-resistant Mycobacterium tuberculosis isolates obtained in Brazil.

We investigated mutations in the genes katG, inhA (regulatory and structural regions), and kasA and the oxyR-ahpC intergenic region of 97 isoniazid (INH)-resistant and 60 INH-susceptible Mycobacterium tuberculosis isolates obtained in two states in Brazil: São Paulo and Paraná. PCR-single-strand conformational polymorphism (PCR-SSCP) was evaluated for screening mutations in regions of prevalence, including codons 315 and 463 of katG, the regulatory region and codons 16 and 94 of inhA, kasA, and the oxyR-ahpC intergenic region. DNA sequencing of PCR amplicons was performed for all isolates with altered PCR-SSCP profiles. Mutations in katG were found in 83 (85.6%) of the 97 INH-resistant isolates, including mutations in codon 315 that occurred in 60 (61.9%) of the INH-resistant isolates and 23 previously unreported katG mutations. Mutations in the inhA promoter region occurred in 25 (25.8%) of the INH-resistant isolates; 6.2% of the isolates had inhA structural gene mutations, and 10.3% had mutations in the oxyR-ahpC intergenic region (one, nucleotide -48, previously unreported). Polymorphisms in the kasA gene occurred in both INH-resistant and INH-susceptible isolates. The most frequent polymorphism encoded a G(269)A substitution. Although KatG(315) substitutions are predominant, novel mutations also appear to be responsible for INH resistance in the two states in Brazil. Since ca. 90.7% of the INH-resistant isolates had mutations identified by SSCP electrophoresis, this method may be a useful genotypic screen for INH resistance.

Antitubercular Agents↗
PubMed2000

Hepatitis E virus immunoglobulin G antibodies in different populations in Campinas, Brazil.

The seroprevalence of anti-hepatitis E virus (HEV) antibodies was investigated by enzyme immunoassay in 205 volunteer blood donors, 214 women who attended a center for anonymous testing for human immunodeficiency virus (HIV) infection, and 170 hospital employees in Campinas, a city in southeastern Brazil. The prevalence of anti-HEV antibodies ranged from 2.6% (3 of 117) in health care professionals to 17.7% (38 of 214) in women who considered themselves at risk for HIV. The prevalence of anti-HEV antibodies in health care professionals was not significantly different from that in healthy blood donors (3.0%, 5 of 165) and blood donors with raised alanine aminotransferase levels (7.5%, 3 of 40). The prevalence of anti-HEV antibodies (13.2%, 7 of 53) in cleaning service workers at a University hospital was similar to that among women at risk for HIV infection. These results suggest that HEV is circulating in southeastern Brazil and that low socioeconomic status is an important risk factor for HEV infection in this region.

Adolescent↗