Search

Data on features of Pneumocystis primary infection in infancy are still fragmented. To study Pneumocystis primary infection, 192 infants who were monitored for acute pulmonary disease or fever over a 40-month period were retrospectively investigated. P. jirovecii detection on archival nasopharyngeal aspirates was performed using a qPCR assay. Factors associated with P. jirovecii were assessed using univariate and multivariate analyses. P. jirovecii genotypes in infants and a control group of adults contemporaneously diagnosed with Pneumocystis pneumonia were identified using unilocus, bilocus, and multilocus sequence typing (MLST). P. jirovecii was detected in 35 infants (18.2%). The univariate analysis pointed out four factors: viral infection (P =.035, OR [IC 95], 2.2 [1.1–4.7]), lower respiratory tract infection (P =.032, OR [IC 95], 2.5 [1.1–5.9]), absence of hospital discharge after birth (P =.003, OR (IC 95), 0.1 (0.02–0.5]), and the 63–189-day group (P <.001, OR [IC 95], 42.2 [5.4–332]). The multivariate analysis confirmed these two latter factors (P =.02, OR [IC 95], 0.1 [0.02–0.72]; P =.005, OR [IC 95], 11.5 [2.1–63.5]). Thus, P. jirovecii acquisition mostly takes place in the community. A comparison of these data with those of previously published studies showed that median and interquartile range of positive-infant ages were close to those observed in Chile, Denmark, and Peru, highlighting similar characteristics. Common unilocus or bilocus genotypes were identified in infants and adults, whereas no MLST genotypes were shared. Therefore, a common reservoir made up of infected infants and adults is still hypothetical. Finally, primary infection is a worldwide phenomenon occurring at the same time in childhood regardless of geographical location, rather than an incidental event. [ABSTRACT FROM AUTHOR]

In an active diarrhea surveillance study of children aged 12-24 months in Lima, Peru, norovirus was the most common pathogen identified. The percentage of mixed (bacterial and noroviral) infections was significantly higher among norovirus-positive samples (53%) than among norovirus-negative samples (12%). The combination of norovirus with the most common bacterial pathogens was associated with increased clinical severity over that of either single-pathogen norovirus or single-pathogen bacterial infections. [ABSTRACT FROM AUTHOR]

Enteroaggregative Escherichia coli (EAEC) causes acute and persistent diarrhea among children, HIV-infected patients, and travelers to developing countries. We have searched for 18 genes-encoding virulence factors associated with aggregative adherence, dispersion, biofilm, toxins, serine protease autotransporters of Enterobacteriaceae (SPATEs) and siderophores, analyzed in 172 well-characterized EAEC strains (aggR +) isolated from stool samples of 97 children with diarrhea and 75 healthy controls from a passive surveillance diarrhea cohort study in Peru. Eighty-one different genetic profiles were identified, 37 were found only associated with diarrhea and 25 with control samples. The most frequent genetic profile was aggC + aatA + aap + shf + fyuA +, present in 19 strains, including diarrhea and controls. The profile set1A + set1B + pic + was associated with diarrhea (P < 0.05). Of all genes evaluated, the most frequent were aatA (CVD 342) present in 159 strains (92.4%) and fyuA in 157 (91.3%). When EAEC strains were analyzed as a single pathogen (excluding co-infections), only pic was associated with diarrhea (P < 0.05) and with prolonged diarrhea (diarrhea ≥ 7 days) (P < 0.05). In summary, this is the first report on the prevalence of a large set of EAEC virulence genes and its association with diarrhea in Peruvian children. More studies are needed to elucidate the exact role of each virulence factor. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Neonatal sepsis is the third leading cause of neonatal mortality and a major public health problem, especially in developing countries. Although recent medical advances have improved neonatal care, many challenges remain in the diagnosis and management of neonatal infections. The diagnosis of neonatal sepsis is complicated by the frequent presence of noninfectious conditions that resemble sepsis, especially in preterm infants, and by the absence of optimal diagnostic tests. Since neonatal sepsis is a high-risk disease, especially in preterm infants, clinicians are compelled to empirically administer antibiotics to infants with risk factors and/or signs of suspected sepsis. Unfortunately, both broad-spectrum antibiotics and prolonged treatment with empirical antibiotics are associated with adverse outcomes and increase antimicrobial resistance rates. Given the high incidence and mortality of sepsis in preterm infants and its long-term consequences on growth and development, efforts to reduce the rates of infection in this vulnerable population are one of the most important interventions in neonatal care. In this review, we discuss the most common questions and challenges in the diagnosis and management of neonatal sepsis, with a focus on developing countries. [ABSTRACT FROM AUTHOR]

Background. Enteropathogenic Escherichia coli (EPEC) strains are pediatric pathogens commonly isolated from both healthy and sick children with diarrhea in areas of endemicity. The aim of this study was to compare the bacterial load of EPEC isolated from stool samples from children with and without diarrhea to determine whether bacterial load might be a useful tool for further study of this phenomenon. Methods. EPEC was detected by polymerase chain reaction (PCR) of colonies isolated on MacConkey plates from 53 diarrheal and 90 healthy children aged<2 years. DNA was isolated fromstool samples by cetyltrimethylammonium bromide extraction. To standardize quantification by quantitative real-time PCR (qRT-PCR), the correlation between fluorescence threshold cycle and copy number of the intimin gene of EPEC E2348/69 was determined. Results. The detection limit of qRT-PCR was 5 bacteria/mg stool. The geometric mean load in diarrhea was 299 bacteria/mg (95% confidence interval [CI], 77-1164 bacteria/mg), compared with 29 bacteria/mg (95% CI, 10-87 bacteria/mg) in control subjects (P = .016). Bacterial load was significantly higher in children with diarrhea than in control subjects among children <12 months of age (178 vs 5 bacteria/mg; P = .006) and among children with EPEC as the sole pathogen (463 vs 24 bacteria/mg; P = .006). Conclusions. EPEC load measured by qRT-PCR is higher in diarrheal than in healthy children qRT-PCR may be useful to study the relationship between disease and colonization in settings of endemicity. [ABSTRACT FROM AUTHOR]

We analyzed a randomly selected group of 30 diffusely adherent (DAEC), 30 enteropathogenic, 30 enteroaggregative, and five Shiga toxin-producing Escherichia coli strains isolated from children with diarrhea. Enterotoxigenic E. coli (ETEC) colonization factors (CFs) were evaluated by a dot-blot assay using 21 CF-specific monoclonal antibodies. Out of 95 non-ETEC strains, three DAEC were found to express coli surface antigen 20 (CS20). No other E. coli expressed CFs. We confirmed the three CS20-positive strains as ETEC-negative by repeat PCR and as toxin-negative by ganglioside-GM1-enzyme-linked immunosorbent assay. To our knowledge, this is the first study that has identified currently recognized CFs in non-ETEC diarrheagenic E. coli strains identified using molecular methods. CFs may be an unrecognized relevant adherence factor in other E. coli, which may then play a role in pathogenesis and the immune response of the host. [ABSTRACT FROM AUTHOR]

Background. Diarrheagenic Escherichia coli strains are being recognized as important pediatric enteropathogens worldwide. However, it is unclear whether there are differences in age-related susceptibility to specific strains, especially among infants. Methods. We conducted a passive surveillance cohort study of diarrhea that involved 1034 children aged 2-12 months in Lima, Peru. Control stool samples were collected from randomly selected children without diarrhea. All samples were analyzed for common enteric pathogens and for diarrheagenic E. coli with use of multiplex real-time polymerase chain reaction. Results. The most frequently isolated pathogens in 1065 diarrheal episodes were diarrheagenic E. coli strains (31%), including enteroaggregative (15.1%) and enteropathogenic E. coli (7.6%). Diarrheagenic E. coli, Campylobacter species, and rotavirus were more frequently isolated from infants aged ≥6 months. Among older infants, diffusely adherent E. coli and enterotoxigenic E. coli were more frequently isolated from diarrheal samples than from control samples (P < .05). Children aged ≥6 months who were infected with enterotoxigenic E. coli had a 4.56-fold increased risk of diarrhea (95% confidence interval, 1.20-17.28), compared with younger children. Persistent diarrhea was more common in infants aged <6 months (13.5% vs 3.6%; P < .001). Among children with diarrheagenic E. coli-positive samples, coinfections with other pathogens were more common in children with diarrhea than in control children (40.1% vs 15.6%; P < .001). Conclusions. Diarrheagenic E. coli strains were more frequently isolated in samples from older infants. In this setting with high frequency of pathogen exposure and high frequency of breastfeeding, we hypothesize that the major age-related differences result from decreased exposure to milk-related protective factors and from increased exposure to contaminated food and water. [ABSTRACT FROM AUTHOR]

Summary: Enteropathogenic Escherichia coli (EPEC) are among the most important pathogens infecting children worldwide and are one of the main causes of persistent diarrhea. EPEC were originally serogroup-defined E. coli associated with infantile diarrhea. As various mechanisms of pathogenesis have been discovered, EPEC classification has come to be based on the presence of specific genes. The eae (intimin) and bfpA (bundle-forming pilus) genes have both been used for identification of EPEC and for subdivision of this group of bacteria into typical and atypical strains. For many years typical EPEC have been considered to be the leading cause of infantile diarrhea in developing countries and were considered rare in industrialized countries. However, current data suggests that atypical EPEC are more prevalent than typical EPEC in both developing and developed countries. Moreover, the duration of diarrhea in patients infected with atypical EPEC is significantly longer than that caused by other pathogens. When comparing the isolation rates of EPEC among children with diarrhea and healthy controls without diarrhea, in general, there is a higher isolation rate in diarrhea, although not significantly higher in all studies. These inconsistencies probably are related to the study patient populations, reflecting a possible age-related susceptibility to infection. [Copyright &y& Elsevier]

Lactoferrin is a glycoprotein present in most human mucosal secretions, including human milk. Lactoferrin is bacteriostatic in low iron media and, in some settings, bactericidal. Lactoferrin impairs ability of Shigella flexneri serotype 5 strain M90T to invade HeLa cells. To determine the mechanism by which lactoferrin decreases invasiveness of Shigella organisms, its effect on the major virulence proteins responsible for bacterial uptake by host cells was evaluated. Lactoferrin induced degradation of invasion plasmid antigens IpaB and, to a lesser extent, IpaC, the key proteins responsible for bacteria-directed phagocytosis by mammalian cells. The lipid A-binding N-terminal portion of lactoferrin (residues 1-33) induces release of invasion antigens but does not induce degradation of IpaBC. Lactoferrin does not directly degrade previously released invasion plasmid antigens but works by making IpaBC susceptible to breakdown by surface-expressed protease(s). [ABSTRACT FROM AUTHOR]

Summary: 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. [ABSTRACT FROM AUTHOR]

We conducted a randomized, double-blind, placebo-controlled trial comparing supplementation with bovine lactoferrin versus placebo for the prevention of diarrhea in children. Comparison of overall diarrhea incidence and prevalence rates found no significant difference between the 2 groups. However, there was a lower prevalence of colonization with Giardia species and better growth among children in the lactoferrin group. [ABSTRACT FROM AUTHOR]