RESUMO
Salmonella gallinarum is the causative agent of fowl typhoid. Being a Gram-negative bacteria, its outer membrane proteins (OMP) can be regulated by different microenvironments. S. gallinarum was cultured under the following conditions: nutrient broth (NB), NB supplemented with serum from specific pathogen-free birds (NBS) and NB with serum incubated at 56 °C prior to incubation with the bacteria (NBSD); OMP were subsequently extracted. Several changes were observed in the apparent expression of OMP, mainly a decrease in an OMP with a size of 30 kDa, approximately, under the NBS condition. In contrast, the same event was not observed in NB and NBSD when using one- and two-dimensional polyacrylamide gels (SDS-PAGE). Using the OMP with a size of 30 kDa, approximately, as antigen in indirect ELISA, we were able to differentiate serum from healthy and vaccinated birds, as well as birds infected with S. gallinarum and S. enteritidis. The amino-terminal of this protein was sequenced, showing 100 % identity with OmpA of S. typhimurium. Subsequently, we designed primers to amplify the gene by PCR. The partial sequence of the amplified gene showed 100 % identity with OmpA of S. gallinarum. (1) Heat-labile serum components influence the presence of OmpA in the OM of S. gallinarum; (2) by the way of ELISA, OmpA allows to specifically differentiate healthy from diseased birds.
Assuntos
Proteínas da Membrana Bacteriana Externa/metabolismo , Salmonella , Soro/química , Animais , Proteínas da Membrana Bacteriana Externa/genética , Galinhas , Eletroforese em Gel de Poliacrilamida , Temperatura Alta , Reação em Cadeia da Polimerase , Salmonella/genética , Salmonella/crescimento & desenvolvimentoRESUMO
BACKGROUND: Post-infectious irritable bowel syndrome (PI-IBS) prevalence, small intestinal bacterial overgrowth (SIBO), altered microbiota, low-grade inflammation, and antibiotic therapy in IBS are all controversial issues. AIMS: To conduct an evidence-based review of these factors. METHODS: A review of the literature was carried out up to July 2012, with the inclusion of additional articles as far as August 2013, all of which were analyzed through the Oxford Centre for Evidence-Based Medicine (OCEBM) system. RESULTS: 1.There is greater SIBO probability in IBS when breath tests are performed, but prevalence varies widely (2-84%). 2.The gut microbiota in individuals with IBS is different from that in healthy subjects, but a common characteristic present in all the patients has not been established. 3.The incidence and prevalence of PI-IBS varies from 9-10% and 3-17%, respectively, and the latter decreases over time. Bacterial etiology is the most frequent but post-viral and parasitic cases have been reported. 4.A sub-group of patients has increased enterochromaffin cells, intraepithelial lymphocytes, and mast cells in the intestinal mucosa, but no differences between PI-IBS and non-PI-IBS have been determined. 5.Methanogenic microbiota has been associated with IBS with constipation. 6.Rifaximin at doses of 400mg TID/10days or 550mg TID/14days is effective treatment for the majority of overall symptoms and abdominal bloating in IBS. Retreatment effectiveness appears to be similar to that of the first cycle. CONCLUSIONS: Further studies are required to determine the nature of the gut microbiota in IBS and the differences in low-grade inflammation between PI-IBS and non-PI-IBS. Rifaximin has shown itself to be effective treatment for IBS, regardless of prior factors.
Assuntos
Gastroenteropatias/microbiologia , Gastroenteropatias/patologia , Síndrome do Intestino Irritável/microbiologia , Síndrome do Intestino Irritável/patologia , Microbiota , Medicina Baseada em Evidências , HumanosRESUMO
Helicobacter pylori infects around 50% of the world's population and is associated with diverse pathologies. In the most severe cases, the bacterium causes peptic ulcers and gastric cancer. The interplay between H. pylori and the host's immune response may help to determine the specific outcome of the infection. To study the relationship between antibody subclasses and variation in immune recognition, we determined the immunoglobulin G1 and 2 (IgG1 and IgG2) titres of sera obtained from patients with different H. pylori-associated pathologies. IgG1 and IgG2 titres were determined by ELISA in 44 sera of patients with different H. pylori-associated diseases (peptic ulcer, bleeding peptic ulcers, gastric cancer and dyspepsia). Soluble proteins from lysates were obtained from 12 different clinical isolates from similar associated diseases. We found that soluble proteins from lysates of H. pylori strains (SPLHP) recognition patterns in these sera were highly variable. Overall, IgG2 titres were higher than the IgG1 titres in the infected patients. In particular, those with peptic ulcers showed marked elevation in IgG2/IgG1 ratios, while SPLHPs from dyspeptic patients resulted in high IgG1 titres. Our results reveal that correlation of antibody subclass titres with Th1/Th2 markers may aid pathology characterization and show a potential diagnosis that could be formally evaluated in other studies.
Assuntos
Infecções por Helicobacter/imunologia , Helicobacter pylori/imunologia , Imunoglobulina G/imunologia , Gastropatias/imunologia , Gastropatias/microbiologia , Estudos Transversais , Ensaio de Imunoadsorção Enzimática , Infecções por Helicobacter/sangue , Infecções por Helicobacter/microbiologia , Humanos , Imunoglobulina G/sangue , Leucócitos Mononucleares/imunologia , Pessoa de Meia-Idade , Estudos Prospectivos , Estatísticas não Paramétricas , Gastropatias/sangueRESUMO
We investigated the presence of nontuberculous mycobacteria (NTM) in three Mexican aquatic systems to evaluate the prevalence with the distribution of NTM species. Key physicochemical parameters of the water samples were determined to find correlations with the species' distributions. We used multilocus sequence analysis (MLSA) based on hsp65, rpoB, and 16S rRNA fragments to determine their taxonomic affiliations. NTM were recovered from water distribution systems and reclaimed water from the Mexico City Metropolitan Area (MCMA). The isolated species were associated with a temperature of 21°C and pH >7.7. The phylogenetic analysis showed that eight of the 14 different NTM strains were unambiguously classifiable: Mycobacterium peregrinum, M. nonchromogenicum (2), M. smegmatis (2), M. fortuitum, M. avium ssp. hominissuis, M. arupense, M. gordonae, and M. chitae. One strain was tentatively identified as M. mantenni/ scrofulaceum and another strain was related to M. porcinum/M. septicum. All NTM species identified in the water distribution system were also detected in the reclaimed water, but some species from the reclaimed water were not found in the water distribution systems. Two of the identified species found in the reclaimed water, M. avium and M. fortuitum, are considered important human opportunistic pathogens.
Assuntos
Água Doce/microbiologia , Micobactérias não Tuberculosas/classificação , Micobactérias não Tuberculosas/isolamento & purificação , Proteínas de Bactérias/genética , Chaperonina 60/genética , RNA Polimerases Dirigidas por DNA/genética , Água Doce/química , Concentração de Íons de Hidrogênio , México , Dados de Sequência Molecular , Micobactérias não Tuberculosas/genética , Prevalência , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , TemperaturaRESUMO
Studies of patients with active tuberculosis (TB) and infected healthy individuals have shown that interferon (IFN)-gamma is present in sites of Mycobacterium tuberculosis infection in comparable levels. This suggests that there is a deficiency in the macrophage response to IFN-gamma in TB patients. We used recombinant human IFN-gamma to stimulate adherent monocyte-derived macrophages from three groups of people: patients with active tuberculosis (TBP), their healthy household contacts (HHC) and healthy uninfected controls from the community (CC). We then evaluated the ability of the macrophages to inhibit the growth of M. tuberculosis H37Rv as well as their cytokine profile at early in infection (48 h). After IFN-gamma treatment, macrophages of healthy individuals (HHC and CC) controlled M. tuberculosis growth and produced mainly nitric oxide (NO) and interleukin (IL)-12p70, whereas TBP macrophages did not kill M. tuberculosis. Additionally, TBP macrophages produced low levels of NO and IL-12p70 and high levels of tumour necrosis factor (TNF)-alpha and IL-10. Transforming growth factor (TGF)-beta levels were similar among all three groups. M. tuberculosis infection had little effect on the cytokine response after IFN-gamma stimulus, but infection alone induced more IL-10 and TGF-beta in TBP macrophages. There were no differences in Stat1 nuclear translocation and DNA binding between the groups. However, the phosphorylated Stat1 and c-Jun (AP-1) in nuclear protein extracts was diminished in TBP macrophages compared to macrophages of healthy individuals. These results indicate an impairment of Stat1-dependent and Stat1-independent IFN-gamma signalling in macrophages of people with active tuberculosis, suggesting a different molecular regulation that could impact macrophage functionality and disease outcome.
Assuntos
Interferon gama/imunologia , Proteínas Quinases JNK Ativadas por Mitógeno/metabolismo , Macrófagos/imunologia , Mycobacterium tuberculosis , Fator de Transcrição STAT1/metabolismo , Tuberculose Pulmonar/imunologia , Adulto , Western Blotting/métodos , Estudos de Casos e Controles , Núcleo Celular/química , Núcleo Celular/metabolismo , Ensaio de Unidades Formadoras de Colônias , Ensaio de Desvio de Mobilidade Eletroforética , Humanos , Interferon gama/farmacologia , Interleucina-10/análise , Interleucina-10/imunologia , Proteínas Quinases JNK Ativadas por Mitógeno/análise , Macrófagos/metabolismo , Pessoa de Meia-Idade , Óxido Nítrico/análise , Proteínas Recombinantes , Fator de Transcrição STAT1/análise , Fator de Transcrição STAT5 , Estatísticas não Paramétricas , Fator de Crescimento Transformador beta/análise , Fator de Crescimento Transformador beta/imunologia , Tuberculose Pulmonar/metabolismo , Tuberculose Pulmonar/transmissão , Proteínas Supressoras de Tumor , Adulto JovemRESUMO
Mycobacterium tuberculosis complex species survive and replicate in phagosomes of the host cell. Cell death (CD) has been highlighted as one of the probable outcomes in this host-pathogen interaction. Previously, our group demonstrated macrophage apoptosis as a consequence of Mycobacterium bovis infection. In this study, we aimed to identify the contribution of apoptotic effector elements in M. bovis-induced CD. Bovine macrophages were either infected with M. bovis (multiplicity of infection, 10:1) or treated with an M. bovis cell extract (CFE). Structural changes compatible with CD were evaluated. Chromatin condensation was increased three times by the CFE. On the other hand, a terminal deoxynucleotidyltransferase-mediated dUTP-biotin nick end labeling (TUNEL) assay demonstrated that levels of DNA fragmentation induced by M. bovis and CFE were 53.7% +/- 24% and 38.9% +/- 14%, respectively, whereas control cells had a basal proportion of 8.9% +/- 4.1%. Rates of DNA fragmentation were unaffected by the presence of the pan-caspase inhibitor N-benzyloxycarbonyl-Val-Ala-Asp (z-VAD). Cells treated with 100 mug of CFE for 12 h had a fivefold decrease in the level of mitochondrial outer membrane permeabilization compared to that of untreated cells. Neither M. bovis infection nor CFE treatment induced activation of caspase 3, 8, or 9. Translocation of apoptosis-inducing factor (AIF) to the nucleus was identified in 32% +/- 3.5% and 26.3% +/- 4.9% of M. bovis-infected and CFE-treated cells, respectively. Incubation of macrophages with z-VAD prior to infection did not alter the percentage of cells showing AIF translocation. Our data suggest that M. bovis-induced CD in bovine macrophages is caspase independent with AIF participation.
Assuntos
Fator de Indução de Apoptose/fisiologia , Apoptose/imunologia , Macrófagos/metabolismo , Macrófagos/patologia , Mycobacterium bovis , Animais , Caspases/fisiologia , Bovinos , Morte Celular/imunologia , Extratos Celulares , Células Cultivadas , Fragmentação do DNA , Macrófagos/enzimologia , Mycobacterium bovis/imunologia , Transporte Proteico/imunologiaRESUMO
The evolution of degradsation capacity and in the viability of Pseudomonas aeruginosa ATCC 10145 acclimated to 25 mg4CP/L degradation and, later, exposed to starvation periods of 24, 48, 72, 96, 132 and 156 hours was studied. Degradation rate heterotrophic plate count and cell cytometry were used to evaluate the starvation influence. Results demonstrated that the exposition of P. aeruginosa to starvation produces a decrease in the viability and activity for the degradation of 4-chlorophenol.
Assuntos
Clorofenóis/metabolismo , Pseudomonas aeruginosa/metabolismo , Poluentes Químicos da Água/metabolismo , Aclimatação , Clorofenóis/química , Fatores de Tempo , Poluentes Químicos da Água/químicaRESUMO
The objective of this study was to assess the prevalence of beta-lactamase production in Haemophilus influenzae clinical isolates obtained throughout Latin America and the West Indies in 1998-1999. Isolates were collected from 15 centres (seven countries), identified by standard methods and grouped by patient age. The overall prevalence of beta-lactamase production was 17.8% (270/1513 isolates). The prevalence of beta-lactamase positive strains varied between countries, with the highest prevalence detected in Panama (23.4%, 29/124) and the lowest in the West Indies (10.5%, 4/38). beta-Lactamase-positive strains were more frequently isolated from children aged < or =3 years (22.0%) and from adults aged > or =65 years (26.5%). The high prevalence of beta-lactamase production found should be considered when choosing empirical antibiotic therapy where H. influenzae is suspected.
Assuntos
Infecções por Haemophilus/microbiologia , Haemophilus influenzae/enzimologia , Haemophilus influenzae/isolamento & purificação , Resistência beta-Lactâmica , beta-Lactamases/metabolismo , Adulto , Idoso , Antibacterianos/farmacologia , Pré-Escolar , Feminino , Haemophilus influenzae/efeitos dos fármacos , Humanos , Lactente , América Latina , Masculino , Pessoa de Meia-Idade , beta-LactamasRESUMO
BACKGROUND: Helicobacter pylori infection is common in the Mexican population; however, sources, routes, and risk factors for infection as well as mode of transmission remain unclear. METHODS: H. pylori was detected by polymerase chain reaction (PCR) technique in three aquatic systems located in the Mexico City area. In addition, microbiologic cultures and physicochemical parameters were measured. The systems were sampled over an 18-month period (1997-1999), resulting in a total of 212 samples for the different analyses. RESULTS: Twenty-one percent of the samples (16/77) were positive for H. pylori; of these, 42% (5/12) were confirmed for cagA gene detection by PCR hybridization. Microbiologic samples (n = 74) yielded Aeromonas hydrophila, Aeromonas caviae, Aeromonas veronii, and Vibrio fluvialis. In the samples for physicochemical analyses (n = 61), low concentrations of dissolved oxygen were detected and residual chlorine was less than the inactivation dose, both providing conditions for potential survival of H. pylori and other enteric pathogens in these environments. CONCLUSIONS: The results of this study suggest that, in Mexico City, water used for human consumption and irrigation may play an important role as a vehicle in the transmission of H. pylori as well as infection by other known enteric pathogens.
Assuntos
Antígenos de Bactérias , Enterobacteriaceae/isolamento & purificação , Água Doce/microbiologia , Helicobacter pylori/isolamento & purificação , Microbiologia da Água , Aeromonas/isolamento & purificação , Proteínas de Bactérias/análise , Reservatórios de Doenças , Enterococcus/isolamento & purificação , Helicobacter pylori/genética , México , Reação em Cadeia da Polimerase , RNA Bacteriano/genética , RNA Ribossômico 16S/genética , Saúde da População Urbana , Vibrio/isolamento & purificação , Poluição da ÁguaRESUMO
Helicobacter pylori infection is associated with peptic ulcers and gastric cancer in humans. Transmission of H. pylori is still not certain with some epidemiological data suggesting water as a possible transmission route. The objective of this study was to detect H. pylori 16S rRNA gene in five water systems in the Mexico City area. Samples were taken between 1997 and 2000 from extraction wells (system 1), from dams used as water sources, both pre- and post-treatment (systems 2 and 3), treated wastewater (system 4) and non-treated wastewater (system 5). Detection of the H. pylori 16S rRNA gene in water samples was carried out using nested PCR in 139 water samples and confirmed by using cagA gene detection by PCR-hybridisation. The results showed the presence of H. pylori in 58 (42%) of the water samples in total with a prevalence of 68% in system 1, 100% in system 2, 0% in system 3, 17% in system 4 and 20% in system 5. This first stage showed the presence of H. pylori in the tested water systems; nevertheless, viability of the microorganism in water and vegetables needs to be confirmed as well as demonstration of a relationship between human and environmental strains.
Assuntos
DNA Bacteriano/análise , Helicobacter pylori/isolamento & purificação , RNA Ribossômico 16S/análise , Abastecimento de Água , Agricultura , Cidades , Monitoramento Ambiental , Humanos , México , Reação em Cadeia da Polimerase , Saúde Pública , Purificação da ÁguaRESUMO
Helicobacter pylori virulence determinants have not previously been studied in detail in Latin Americans with H. pylori infections. We characterized the vacA (vacuolating cytotoxin gene A) and cagA (cytotoxin-associated gene A) types of more than 400 single-colony isolates from 20 patients in Mexico City. For 17 patients H. pylori strains of two or more different vacA genotypes were isolated from gastric biopsy specimens, indicating infection with two or more strains of H. pylori. The most frequent vacA genotype was s1b/m1. vacA diversity was more marked than that described previously, in that isolates from seven patients had untypeable vacA midregions and isolates from nine patients had type s1 signal sequence coding regions which could not be further subtyped. Previously undescribed vacA type s2/m1 strains were found in five patients. All patients were infected with cagA-positive strains, but occasionally, these coexisted with small numbers of cagA-negative strains. In conclusion, coinfection with multiple H. pylori strains is common in Mexico, and vacA in these strains is genetically more diverse than has been described in other populations.
Assuntos
Antígenos de Bactérias , Proteínas de Bactérias/genética , Genes Bacterianos , Helicobacter pylori/classificação , Adulto , Idoso , Genótipo , Células HeLa , Helicobacter pylori/genética , Helicobacter pylori/patogenicidade , Humanos , Pessoa de Meia-IdadeRESUMO
OBJECTIVE: To estimate the frequency of H. pylori clinical isolates resistant to six commonly used antimicrobials. DESIGN: Cross-sectional observational study. SETTING: A tertiary-referral health care institution in Mexico City. PARTICIPANTS: 31 isolates of H. pylori from 31 patients with chronic antral gastritis were obtained from gastric mucosal biopsy specimens. MAIN OUTCOME MEASURE: The Minimum Inhibitory Concentration (MIC) to ampicillin, amoxycillin, tetracycline, doxycycline, metronidazole and to colloidal bismuth subcitrate was determined by the agar plate dilution test. RESULTS: All isolates showed to be susceptible to the former four antibiotics but only in 46% and 55% growth was inhibited by 8 micrograms/mL and 16 micrograms/mL of metronidazole, respectively. All isolates were inhibited by < or = 128 micrograms/mL of bismuth. A 50% increase in the percentage of metronidazole-resistant isolates (MIC > or = 8 micrograms/mL) between 1988 to 1992 was observed. CONCLUSION: There is a need of future studies in our setting aimed at assessing the cost/effectiveness of diverse H. pylori-associated peptic ulcer treatment options.
Assuntos
Quimioterapia Combinada/farmacologia , Gastrite/tratamento farmacológico , Infecções por Helicobacter/tratamento farmacológico , Helicobacter pylori/efeitos dos fármacos , Compostos Organometálicos/farmacologia , Amoxicilina/farmacologia , Amoxicilina/uso terapêutico , Ampicilina/farmacologia , Ampicilina/uso terapêutico , Análise Custo-Benefício , Doxiciclina/farmacologia , Doxiciclina/uso terapêutico , Resistência Microbiana a Medicamentos , Quimioterapia Combinada/economia , Quimioterapia Combinada/uso terapêutico , Gastrite/economia , Gastrite/epidemiologia , Gastrite/microbiologia , Infecções por Helicobacter/economia , Infecções por Helicobacter/epidemiologia , Infecções por Helicobacter/microbiologia , Hospitais Especializados/estatística & dados numéricos , Humanos , Metronidazol/farmacologia , Metronidazol/uso terapêutico , Compostos Organometálicos/uso terapêutico , Tetraciclina/farmacologia , Tetraciclina/uso terapêutico , Resultado do TratamentoRESUMO
Colonization factor antigens (CFAs and PCFs) are important virulence factors of Escherichia coli (ETEC) diarrhea. Antibodies to CFAs produced after ETEC infection are protective; however, the CFA epitopes which induce protective antibodies have not yet been characterized. This study is the characterization of the immune response to CFAs at molecular level and identification of the epitopes associated with inhibition of cell-adherence and protection that will lead to the development of methods to prevent ETEC infection and disease. The aim of this study was the characterization of the linear epitopes of CFA/I that react with sera from acute and convalescent phase of ETEC-in-fected children, with adult sera from endemic and non-endemic areas, with monoclonal antibodies (Mabs) and with hyperimmune antiserum to CFAs and PCFs different from CFA/I. Three linear and common epitopes were recognized among the CFA/I in child sera and adult sera from endemic areas and with hyperimmune sera against other known CFAs and putative ETEC colonization factors.
Assuntos
Enterotoxinas/imunologia , Epitopos/imunologia , Escherichia coli/imunologia , Proteínas de Fímbrias , Fímbrias Bacterianas/imunologia , Adulto , Sequência de Aminoácidos , Animais , Anticorpos Antibacterianos/análise , Anticorpos Antibacterianos/imunologia , Anticorpos Monoclonais/imunologia , Antígenos de Bactérias/análise , Antígenos de Bactérias/imunologia , Proteínas de Bactérias/análise , Proteínas de Bactérias/genética , Proteínas de Bactérias/imunologia , Vacinas Bacterianas/imunologia , Criança , Ensaio de Imunoadsorção Enzimática , Escherichia coli/patogenicidade , Infecções por Escherichia coli/imunologia , Humanos , Imunoglobulina G/análise , México , Dados de Sequência Molecular , Pili Sexual/imunologia , Coelhos , Espectrofotometria , VirulênciaRESUMO
A microdilution method was utilized for determining susceptibility to several antimicrobial agents in 142 bacterial blood culture isolates obtained during a one year period. Associated clinical features were also identified. Three cases of polymicrobial bacteriemia were found. Endocarditis was the most frequent source of bacteriemia (28.5%) and the viridans streptococci were the most frequently isolated microorganism (53%). Surprisingly, half of the bacteriemic episodes corresponded to a nosocomial infection most of which were due to staphylococci (25%) and Enterobacter sp (22%). Viridans streptococci group were 61.5% resistant to penicillin (MIC > 0.12 micrograms/mL). These strains also showed a 31% resistance to ceftriaxone (MIC > 8 micrograms/mL). The staphylococcal strains showed a 19% resistance to oxacillin; this resistance occurred for coagulase negative staphylococcis in 32% (6/19) and for S. aureus in 9% (2/22). All Gram-positive microorganisms were susceptible to vancomycin. The enterobacteria group were susceptible to most antimicrobial agents; nevertheless this group showed a 45% resistance to amikacin. In contrast, the non enterobacteria group were resistant to most of the antimicrobial agents tested except to imipenem, ceftazidime and ciprofloxacin. When comparing susceptibility longitudinally, no significative changes were identified, but a significant increase was found in MIC50-90 to amikacin and cephalothin when testing S. aureus, and cefoperazone in the non enterobacteria group.
Assuntos
Bacteriemia/microbiologia , Infecção Hospitalar/microbiologia , Resistência Microbiana a Medicamentos , Endocardite Bacteriana/microbiologia , Antibacterianos/farmacologia , Bacteriemia/tratamento farmacológico , Bactérias/efeitos dos fármacos , Humanos , México , Testes de Sensibilidade MicrobianaRESUMO
The proportion of Shigella infections that occur asymptomatically in young children has not been established. A community-based cohort study of 367 infants was followed prospectively by weekly home visits from January, 1990, through December, 1991. Stool samples were collected weekly and when diarrhea occurred and were tested for Shigella and other enteropathogens. There were 2925 child months of observation and 65 episodes of Shigella infection. There were 3.1 episodes/100 child months during the warm season (May through September) and 0.97 episode/100 child months during the cold season. Shigella infections were rare during the first 6 months of life but increased with age (P < 0.0001). Overall 55% of detected infections were asymptomatic. The proportion of infections that were asymptomatic increased as age increased (P < 0.01). Symptom status was not significantly associated with Shigella species or season. All isolates from symptomatic and asymptomatic children had the 120- to 140-megadalton virulence plasmid. We conclude that infections with virulent strains of Shigella are commonly asymptomatic in Mexican children during the first 2 years of life.
PIP: During January 1990-December 1991, each week, field workers visited the home of 367 children aged 0-24 months from a periurban area southwest of Mexico City (San Pedro Martir and San Andres Totoltepec, Tlalpan) and collected stool specimens from them to determine whether Shigella infections are often asymptomatic. The crude incidence rate of diarrhea, regardless of etiology, was 29 episodes/100 child months during the warmer and rainy months (May-September), while it was 21 episodes/100 child months for the rest of the year (October-April) (relative risk [RR] =1.38). 53 of all children (l4%) had 65 Shigella infections. The overall monthly incidence of symptomatic and asymptomatic Shigella infection was higher during May-September than October-April (3.13 vs. 0.97 episodes/100 children; RR = 3.22). 55% of all Shigella infections (36) were asymptomatic. 32% developed secretory-type diarrhea and 13% had blood present in the stool. The incidence of Shigella infections grew as did the age (0.4-8.2 episodes/100 child months for 0-6 month olds to 18-24 month olds; p 0.0001). The proportion of asymptomatic Shigella infections also increased with age (33% for 0-6 month olds, 40% for 7-12 month olds, 46% for 13-18 month olds, and 78% for 18-24 month olds; p 0.01). Shigella sonnei, S. flexneri, and S. boydii were the only species detected. The 120-140 megadalton virulence plasmid was present in all isolates from asymptomatic and symptomatic children. Mixed infections were rather common in both asymptomatic (47%) and symptomatic (45%) children. Among infants aged less than 12 year months, breast feeding infants were less likely to be infected with Shigella than nonbreast feeding infants (RR = 2.41). On the other hand, among children aged 12-24 months, nonbreast feeding was associated with a lower risk of Shigella infection (RR = 0.69). These findings show that Shigella infections in Mexican children aged 0-24 months range from asymptomatic infections to secretory diarrhea to bloody diarrhea.
Assuntos
Disenteria Bacilar/epidemiologia , Distribuição por Idade , Aleitamento Materno , Estudos de Coortes , Intervalos de Confiança , Disenteria Bacilar/microbiologia , Disenteria Bacilar/fisiopatologia , Fezes/microbiologia , Humanos , Incidência , Lactente , Recém-Nascido , México/epidemiologia , Estudos Prospectivos , Estações do Ano , Shigella boydii/isolamento & purificação , Shigella flexneri/isolamento & purificação , Shigella sonnei/isolamento & purificaçãoRESUMO
Three species of Campylobacter are recognized as enteropathogens in children under five years of age and in immunocompromised patients. Several groups have tried to classify them using biochemical profiles and have found six different patterns which comprise 12 individual tests. We have designed a "Micro Campy" method which identifies C. jejuni, C. coli and C. lari classifying them into several biotypes. Fifty two Campylobacter strains isolated from humans were studied and classified in 24 different patterns. Strains isolated from diarrhea episodes were seen in two specific patterns. We propose the use of this easy to perform method which has a reproducibility higher than 92% in biotyping Campylobacter strains.
Assuntos
Técnicas de Tipagem Bacteriana , Campylobacter/classificação , Campylobacter/efeitos dos fármacos , Campylobacter/isolamento & purificação , Campylobacter/metabolismo , Infecções por Campylobacter/microbiologia , Resistência Microbiana a Medicamentos , Humanos , Microquímica , Especificidade da EspécieRESUMO
To determine sensitivity and specificity of immunofluorescence assay (IFA) for detection of Helicobacter pylori, we studied 151 patients. Biopsies of gastric mucosae were obtained for culture, histological testing, and IFA. H. pylori serum antibodies were tested by enzyme-linked immunosorbent assay. IFA was done on Formalin-preserved, paraffin-embedded biopsies by using rabbit anti-H. pylori and goat anti-rabbit gamma globulin-fluorescein isothiocyanate conjugate. The sensitivity and specificity of IFA compared with culture and Warthin-Starry stain were 93 and 95%, respectively. IFA is an accurate method for the diagnosis of H. pylori infection.
Assuntos
Mucosa Gástrica/microbiologia , Infecções por Helicobacter/diagnóstico , Helicobacter pylori/isolamento & purificação , Adolescente , Adulto , Idoso , Biópsia , Ensaio de Imunoadsorção Enzimática , Feminino , Imunofluorescência , Humanos , Masculino , Pessoa de Meia-Idade , Reprodutibilidade dos Testes , Sensibilidade e EspecificidadeRESUMO
Seroepidemiologic and clinical studies of amoebiasis require improved methods for the detection and titration of anti-Entamoeba histolytica (Eh) trophozoite antibodies. We have developed a Dot-enzyme-linked immunosorbent assay (Dot-ELISA) to titrate anti-Eh antibodies in human serum and colostrum. The anti-Eh serum IgG antibody titers from healthy individuals and from patients with amoebic liver abscess obtained, with our Dot-ELISA were similar to those obtained with a standard ELISA, but the background values were lower. Significant anti-Eh sIgA antibody titers were found in seven out of 42 colostrum samples of mothers of newborn children with diarrhea. Our Dot-ELISA is rapid, inexpensive, and might be used for the diagnosis of individuals and in seroepidemiologic studies of amoebiasis.
Assuntos
Anticorpos Antiprotozoários/análise , Colostro/química , Entamoeba histolytica/imunologia , Ensaio de Imunoadsorção Enzimática , Imunoglobulina A Secretora/análise , Imunoglobulina G/sangue , Abscesso Hepático Amebiano/sangue , Adulto , Animais , Anticorpos Antiprotozoários/sangue , Diarreia Infantil/etiologia , Entamebíase/complicações , Entamebíase/diagnóstico , Feminino , Humanos , Recém-Nascido , Abscesso Hepático Amebiano/imunologia , Masculino , Gravidez , Transtornos Puerperais/diagnóstico , CoelhosRESUMO
A cohort of 228 Mexican children less than 5 years old was followed during the enterotoxigenic Escherichia coli(ETEC) season. The incidence of ETEC diarrhea-associated and asymptomatic infections was determined, and E. coli strains isolated from stool samples were tested for heat-labile and heat-stable toxins and for expression of colonization factor antigens (CFA). Of the children, 61% had at least one ETEC infection. Children with ETEC isolated from stools were more likely to have diarrhea than were ETEC-free age-matched control children (odds ratio [OR] = 4.5; 95% confidence interval [CI] = 2.9-7.0). Strains carrying CFA/IV, CFA/I, or CFA/II were found in 23%, 18%, and 5% of ETEC infections, respectively. The risk of having diarrhea associated with a CFA-expressing versus a CFA-negative ETEC strain was the same (age-adjusted OR = 0.8; 95% CI = 0.4-1.6). These data should be considered in the development of a diarrhea vaccine containing only CFAs.