RESUMO
This study aims to characterize the presence of virulence factors of enterotoxigenic Escherichia coli (ETEC) causing traveler's diarrhea. Among 52 ETEC isolates, the most common toxin type was STh, and the most frequent colonization factors (CFs) were CS21, CS6, and CS3. On the other hand, the nonclassical virulence factors EAST1 and EatA were frequently present.
Assuntos
Diarreia/microbiologia , Escherichia coli Enterotoxigênica/genética , Infecções por Escherichia coli/microbiologia , Genótipo , Escherichia coli Enterotoxigênica/patogenicidade , Humanos , Fatores de Virulência/genéticaRESUMO
BACKGROUND: Antibiotic resistance is increasing worldwide, being of special concern in low- and middle-income countries. The aim of this study was to determine the antimicrobial susceptibility and mechanisms of resistance in 205 enterotoxigenic Escherichia coli (ETEC) isolates from two cohort studies in children <24 months in Lima, Peru. METHODS: ETEC were identified by an in-house multiplex real-time PCR. Susceptibility to 13 antimicrobial agents was tested by disk diffusion; mechanisms of resistance were evaluated by PCR. RESULTS: ETEC isolates were resistant to ampicillin (64%), cotrimoxazole (52%), tetracycline (37%); 39% of the isolates were multidrug-resistant. Heat-stable toxin producing (ETEC-st) (48%) and heat-labile toxin producing ETEC (ETEC-lt) (40%) had higher rates of multidrug resistance than isolates producing both toxins (ETEC-lt-st) (21%), p<0.05. Only 10% of isolates were resistant to nalidixic acid and none to ciprofloxacin or cefotaxime. Ampicillin and sulfamethoxazole resistance were most often associated with blaTEM (69%) and sul2 genes (68%), respectively. Tetracycline resistance was associated with tet(A) (49%) and tet(B) (39%) genes. Azithromycin inhibitory diameters were ≤15 mm in 36% of isolates, with 5% of those presenting the mph(A) gene. CONCLUSIONS: ETEC from Peruvian children are often resistant to older, inexpensive antibiotics, while remaining susceptible to ciprofloxacin, cephalosporins and furazolidone. Fluoroquinolones and azithromycin remain the drugs of choice for ETEC infections in Peru. However, further development of resistance should be closely monitored.
Assuntos
Antibacterianos/uso terapêutico , Azitromicina/uso terapêutico , Diarreia/microbiologia , Escherichia coli Enterotoxigênica/efeitos dos fármacos , Infecções por Escherichia coli/microbiologia , Fluoroquinolonas/uso terapêutico , Pré-Escolar , Estudos de Coortes , Diarreia/tratamento farmacológico , Diarreia/epidemiologia , Método Duplo-Cego , Escherichia coli Enterotoxigênica/isolamento & purificação , Infecções por Escherichia coli/complicações , Infecções por Escherichia coli/tratamento farmacológico , Feminino , Humanos , Lactente , Masculino , Testes de Sensibilidade Microbiana , Peru/epidemiologia , Reação em Cadeia da Polimerase em Tempo RealRESUMO
Secretory diarrhea caused by cholera toxin (CT) is initiated by binding of CT's B subunit (CTB) to GM1-ganglioside on the surface of intestinal cells. Lactoferrin, a breast milk glycoprotein, has shown protective effect against several enteropathogens. The aims of this study were to determine the effect of bovine-lactoferrin (bLF) on CT-induced intestinal fluid accumulation in mice, and the interaction between bLF and CT/CTB with the GM1-ganglioside receptor. Fluid accumulation induced by CT was evaluated in the mouse ileal loop model using 56 BALB/c mice, with and without bLF added before, after or at the same time of CT administration. The effect of bLF in the interaction of CT and CTB with GM1-ganglioside was evaluated by a GM1-enzyme-linked immunosorbent assay. bLF decreased CT-induced fluid accumulation in the ileal loop of mice. The greatest effect was when bLF was added before CT (median, 0.066 vs. 0.166 g/cm, with and without bLF respectively, p<0.01). We conclude that bLF decreases binding of CT and CTB to GM1-ganglioside, suggesting that bLF suppresses CT-induced fluid accumulation by blocking the binding of CTB to GM1-ganglioside. bLF may be effective as adjunctive therapy for treatment of cholera diarrhea.
Assuntos
Toxina da Cólera/metabolismo , Gangliosídeos/metabolismo , Mucosa Intestinal/metabolismo , Lactoferrina/metabolismo , Animais , Bovinos , Cloretos/farmacologia , Relação Dose-Resposta a Droga , Enterotoxinas/biossíntese , Escherichia coli/efeitos dos fármacos , Escherichia coli/crescimento & desenvolvimento , Escherichia coli/metabolismo , Feminino , Compostos Férricos/farmacologia , Gangliosídeo G(M1)/metabolismo , Intestinos/efeitos dos fármacos , Intestinos/patologia , Lactoferrina/farmacologia , Camundongos , Ligação Proteica/efeitos dos fármacos , Receptores de Superfície Celular/metabolismoRESUMO
Norovirus was detected in 17.4% of 224 diarrhoeal samples from children younger than 24 months of age in Lima, in whom all common pathogens had been excluded (pathogen negative). Norovirus was identified more frequently in children older than 12 months of age than in younger children (34% vs 8%, P<0.001). Among norovirus-positive samples, genogroup II was the predominant group (92%). Compared with rotavirus, norovirus episodes tended to be of shorter duration and less severe. The role of norovirus as a cause of diarrhoea and the ascertainment of its severity in developing countries needs further confirmation by future epidemiological studies.
Assuntos
Infecções por Caliciviridae/epidemiologia , Diarreia/epidemiologia , Gastroenterite/epidemiologia , Norovirus/patogenicidade , População Suburbana/estatística & dados numéricos , Infecções por Caliciviridae/virologia , Diarreia/virologia , Feminino , Gastroenterite/virologia , Humanos , Lactente , Masculino , Norovirus/isolamento & purificação , Peru/epidemiologia , Estudos ProspectivosRESUMO
We conducted a prospective study in three hospitals in Lima in human immunodeficiency virus (HIV) children to determine the frequency of diarrheagenic Escherichia coli. Five E. coli colonies/patients were studied by a multiplex real-time polymerase chain reaction to identify the six currently recognized groups of diarrhea-associated E. coli. We have analyzed 70 HIV-associated diarrheal and 70 control samples from HIV-infected children without diarrhea. Among the diarrheal episodes 19% were persistent, 3% dysenteric, and 33% were associated with moderate or severe dehydration. The diarrheagenic E. coli were the most commonly isolated pathogens in diarrhea (19%) and control samples (26%) (P = 0.42), including enteroaggregative (6% versus 10%), enteropathogenic (6% versus 10%), and enterotoxigenic E. coli (4% versus 3%), respectively. The HIV-infected children with diarrhea had the worse age-related immunosuppression, higher viral loads, and were on highly active antiretroviral treatment (HAART) less often than HIV-infected children without diarrhea. Diarrheagenic E. coli were highly resistant to ampicillin (74%) and cotrimoxazole (70%).