A prospective study of rotavirus infection in infants and young children

Diarrhea in neonates, followed as a cohort, and their families was studied prospectively. The families were followed for an average of 16.3 months. Stool and serum specimens were obtained at least every three months. Stool specimens were examined for viruses by electron microscopy and cultured for enteropathogens, and serum specimens were tested for antibodies to rotavirus and Norwalk virus. During the study, 237 episodes of gastroenteritis were observed in 104 infants and their 62 siblings. Rotavirus, detected 82 times in 72 children, was by far the most common enteropathogen. It was associated with gastrointestinal symptoms in 72% (with diarrhea in 65%). Rotavirus diarrhea occurred mostly in winter months and was significantly more frequently associated with respiratory symptoms than were diarrheas with other etiologies. Rotavirus infection was uncommon in the first six months of life, but by two years of age, 62% of the infants had had at least one infection. Neither breast feeding nor the presence of antibody to rotavirus in cord blood appeared to be protective.     

Frequency of bystander exposure to antibiotics for enteropathogenic bacteria among young children in low-resource settings

Children in low-resource settings carry enteric pathogens asymptomatically and are frequently treated with antibiotics, resulting in opportunities for pathogens to be exposed to antibiotics when not the target of treatment (i.e., bystander exposure). We quantified the frequency of bystander antibiotic exposures for enteric pathogens and estimated associations with resistance among children in eight low-resource settings. We analyzed 15,697 antibiotic courses from 1,715 children aged 0 to 2 y from the MAL-ED birth cohort. We calculated the incidence of bystander exposures and attributed exposures to respiratory and diarrheal illnesses. We associated bystander exposure with phenotypic susceptibility of E. coli isolates in the 30 d following exposure and at the level of the study site. There were 744.1 subclinical pathogen exposures to antibiotics per 100 child-years. Enteroaggregative Escherichia coli was the most frequently exposed pathogen, with 229.6 exposures per 100 child-years. Almost all antibiotic exposures for Campylobacter (98.8%), enterotoxigenic E. coli (95.6%), and typical enteropathogenic E. coli (99.4%), and the majority for Shigella (77.6%), occurred when the pathogens were not the target of treatment. Respiratory infections accounted for half (49.9%) and diarrheal illnesses accounted for one-fourth (24.6%) of subclinical enteric bacteria exposures to antibiotics. Bystander exposure of E. coli to class-specific antibiotics was associated with the prevalence of phenotypic resistance at the community level. Antimicrobial stewardship and illness-prevention interventions among children in low-resource settings would have a large ancillary benefit of reducing bystander selection that may contribute to antimicrobial resistance.

Antibiotic use causes selection pressure for antimicrobial resistance (AMR), a growing global public health crisis that threatens to render antibiotics ineffective against many high-burden infections (1). Most of the concern is placed on the development of resistance in the target pathogen of treatment (i.e., the pathogen causing the treated illness). However, systemic treatment also results in antibiotic exposure for commensal bacteria and pathogens carried asymptomatically at the time of treatment (2). Selective pressure for resistance among organisms that are not the target pathogen has been called “bystander selection” (3, 4). While the public health relevance of resistance in nonpathogenic commensal organisms is less clear, bystander selection among pathogens carried asymptomatically at the time of treatment has direct consequences for the development of resistance in those pathogens (4). This type of selection has the potential to promote antibiotic-resistant disease in settings where subclinical carriage of pathogens is common.Children in low-resource settings frequently carry enteric pathogens in the absence of diarrheal symptoms (5). Enteroaggregative Escherichia coli (EAEC), for example, was detected in nearly half (49%) of nondiarrheal stools collected in the first 2 y of life in the Etiology, Risk Factors and Interactions of Enteric Infections and Malnutrition and the Consequences for Child Health and Development Project (MAL-ED) birth cohort study conducted in South America, South Asia, and sub-Saharan Africa (6). Campylobacter and Shigella, which are on the World Health Organization priority pathogen list for concern for AMR (7), were detected in 28% (5) and 10% (8) of nondiarrheal stools, respectively. Antibiotic treatment is also highly common in these populations, with approximately five treatment courses per child-year observed in MAL-ED (9). Children were treated with more than one antibiotic course per child year for diarrhea alone (10), despite treatment guidelines that only recommend treatment for dysentery (11), which comprised less than 5% of diarrheal episodes (10). For these reasons, children in low-resource settings represent a unique population in which the burden of bystander selection on enteric pathogens could be particularly high.Antimicrobial stewardship interventions to prevent antibiotic overuse and interventions to prevent illnesses that prompt antibiotic treatment, such as vaccines, could have the ancillary benefit of reducing bystander selection (12). However, the magnitude of this potential impact is unknown. A prior study quantified the proportion of antibiotic exposures for specific pathogens that were not related to the treatment of that pathogen based on modeled data from unrelated sources (3). The observational birth cohort study, MAL-ED, provides a unique opportunity to characterize bystander antibiotic exposure directly since testing for enteric pathogen carriage was conducted monthly in nondiarrheal stools from birth to 2 y of age, and antibiotic use was comprehensively documented during twice-weekly surveillance visits. Here, we aimed to quantify the absolute frequency of bystander antibiotic exposures for enteric bacterial pathogens carried asymptomatically at the time of treatment among children in MAL-ED. We compared the frequency of antibiotic exposures that occurred when the bacteria were the target pathogen to when they were bystanders and attributed bystander exposure to specific indications for treatment. We also identified child characteristics that were associated with bystander antibiotic exposures. Finally, we assessed the association between bystander antibiotic exposure and resistance both at the individual and the community level using E. coli as a model organism.     

Enterotoxigenic Escherichia coli infections and diarrhea in a cohort of young children in Guinea-Bissau

In an effort to describe the natural history of enterotoxigenic Escherichia coli (ETEC) infection and diarrhea, 200 children in Guinea-Bissau, West Africa, were followed up from birth until up to age 2 years with weekly stool specimen collection, regardless of whether the children had diarrhea. ETEC isolates were tested for the presence of the porcine and human heat-stable toxins (STp and STh), the heat-labile toxin (LT), and 18 of 21 known colonization factors (CFs). The rate of primary infections increased substantially after age 3 or 6 months (depending on the type of ETEC causing the infection). The pathogenicity of STh-containing ETEC was substantially higher than that of STp-containing ETEC, and STp and STh were associated with separate sets of CFs. Small epidemics were observed, mainly caused by STh-containing ETEC. The difference in epidemic propensity, CF association, and pathogenicity suggests that STh- and STp-containing ETEC represent 2 different groups of human ETEC. Vaccines should primarily target STh-containing ETEC.     

A prospective case-control study of the role of astrovirus in acute diarrhea among hospitalized young children

This study examines the importance of astroviruses as a cause of acute diarrhea in hospitalized children <10 years old during a 5-year period. Stools were screened by electron microscopy and were tested for astrovirus, rotavirus, and enteric adenovirus by EIA. During the study, 14.6% of hospitalized children had diarrhea. Astroviruses were second only to rotaviruses as etiologic agents of both community-acquired and nosocomial diarrhea. Community-acquired astrovirus infection occurred in 6.8% of patients, and nosocomial disease occurred in 16.2%. Most cases occurred from March through June, and astrovirus type 1 was the most common. The symptoms of astrovirus-infected children were similar to those of children with rotavirus infection. However, astrovirus-infected children had a lower median age, less dehydration, and lower symptom severity scores and were less likely to have been admitted for gastroenteritis than were children with rotavirus. Astrovirus, for which only rehydration therapy is required, should be considered as another common diarrheal pathogen in children <2 years old.     

A prospective study of enteropathogenic Escherichia coli in endemic diarrheal disease.

The rate of isolation of Escherichia coli belonging to the traditional serotypes enteropathogenic for infants was studied prospectively in two groups. Group 1 consisted of children with diarrhea and of controls without gastrointestinal disease who were matched for age and inpatient or outpatient status. Group 2 consisted of families entered in a prospective study of rotavirus infections. In group 1 enteropathogenic Escherichia coli were found in 13 (6%) of 220 children younger than 12 months of age and in nine (6%) of 143 children 12--35 months of age, all of whom had diarrhea. Enteropathogenic E. coli were found in only one of an equal number of matched controls (P = 0.002 and 0.004, respectively). In group 2 enteropathogenic E. coli were present in seven (18%) of 38 specimens obtained during diarrheal episodes, as compared with five (1%) of 492 specimens obtained when there was no diarrhea (P less than 0.001). The enteropathogenic E. coli isolated were not enterotoxigenic. The most common serogroup was O111, but many different O:H serotypes were detected. Thus, the association of enteropathogenic E. coli with endemic diarrhea was significant, even though no enteropathogenic mechanism was apparent.     

Phage-associated cytotoxin production by and enteroadhesiveness of enteropathogenic Escherichia coli isolated from infants with diarrhea in West Germany

We assessed the frequency of isolating enteropathogenic Escherichia coli (EPEC) from the stools of infants with diarrhea, the enteroadhesiveness of the EPEC, their production of cytotoxin, and the association of cytotoxin synthesis with lysogenic phages. One hundred twenty-five isolates of EPEC obtained from 1,674 children with diarrhea; three were isolated from 868 controls. Thirty EPEC made elevated levels (greater than or equal to 10(4) 50% cytotoxic doses/mg of cell lysate protein) of a cytotoxin for HeLa cells, and cell-associated cytotoxicity for 27 of these isolates was neutralized by antibody to Shiga toxin. Cell lysates of these isolates were paralytic and lethal for mice. Phages from cytotoxin-producing strains were tested for toxin-converting capacity. Fifteen of 30 such strains harbored toxin-converting phages, and the cytotoxicity of 12 isolates of E. coli K12 transduced with these phages was neutralized by antibody to Shiga toxin. Fifty-seven EPEC exhibited either localized or diffuse adherence to HEp-2 cells, but only nine producers of elevated levels of cytotoxin were adherent.     

Adhesion to cells in culture and plasmid profiles of enteropathogenic Escherichia coli isolated from outbreaks and sporadic cases of infant diarrhoea

Enteropathogenic strains of Escherichia coli (EPEC) that caused 10 outbreaks of infant diarrhoea in the U.K. between 1968 and 1986 were studied. All gave localised adherence (LA) to HEp-2 cells, HeLa cells and Intestine 407 cells in culture. All hybridised with the EPEC adherence factor (EAF) probe. The hybridising sequences were carried on plasmids ranging in size from 26 to 76 MDa. EPEC from sporadic cases of infant diarrhoea occurring between 1979 and 1986 that belonged to the same serotypes as the outbreak strains were also studied. All strains of serotypes O111ab.H2, O114.H2, O119.H6, O127.H6 and O142.H6 gave LA and were EAF-positive. In other serotypes, non-adhering strains or strains giving diffuse adherence were found also. In addition, strains of serotype O128.H2 which gave LA but did not hybridise with the EAF probe were identified. The strains isolated from sporadic cases of diarrhoea in the U.K. were similar, with respect to adhesion and hybridisation, to those isolated from sporadic cases of diarrhoea in developing countries.     

Attaching and effacing enteropathogenic Escherichia coli as a cause of infantile diarrhea in Bangkok.

To identify Escherichia coli that cause infantile diarrhea in Bangkok, Thailand, E. coli isolated in a year-long study of infantile diarrhea were examined for O and H serotypes and virulence determinants. Classic enteropathogenic E. coli (EPEC) were isolated from 28 of 509 infants with diarrhea (cases) and 11 of 509 age-matched controls (P = .009; odds ratio [OR], 2.64). Most of this difference was attributable to EPEC adherence factor (EAF)-positive EPEC that produced an attachment and effacement lesion, as identified in the fluorescence actin staining assay, isolated from 13 cases and 1 control (P = .003; OR, 13.3). EAF-EPEC was isolated from 15 cases and 10 controls (P = .418; OR, 1.52) and EAF+ non-EPEC from 17 cases and 10 controls (P = .242; OR, 1.72). EAF+EPEC that caused an attachment and effacement lesion was found in 3% of children less than 6 months old with diarrhea who were studied in an outpatient clinic in Bangkok in 1988.     

Persistent diarrhea signals a critical period of increased diarrhea burdens and nutritional shortfalls: a prospective cohort study among children in northeastern Brazil

Persistent diarrhea (PD; duration >/=14 days) is a growing part of the global burden of diarrheal diseases. A 45-month prospective cohort study (with illness, nutritional, and microbiologic surveillance) was conducted in a shantytown in northeastern Brazil, to elucidate the epidemiology, nutritional impact, and causes of PD in early childhood (0-3 years of age). A nested case-control design was used to examine children's diarrhea burden and nutritional status before and after a first PD illness. PD illnesses accounted for 8% of episodes and 34% of days of diarrhea. First PD illnesses were preceded by a doubling of acute diarrhea burdens, were followed by further 2.6-3.5-fold increased diarrhea burdens for 18 months, and were associated with acute weight shortfalls. Exclusively breast-fed children had 8-fold lower diarrhea rates than did weaned children. PD-associated etiologic agents included Cryptosporidium, Giardia, enteric adenoviruses, and enterotoxigenic Escherichia coli. PD signals growth shortfalls and increased diarrhea burdens; children with PD merit extended support, and the illness warrants further study to elucidate its prevention, treatment, and impact.     

上海地区婴幼儿院内感染轮状病毒致腹泻病的分子流行病学调查

目的 了解上海地区婴幼儿院内感染轮状病毒(RV)致腹泻病的分子流行病学特征.方法 采用胶体金法和套式PCR,对2006年11月至2008年1月复旦大学附属儿科医院收集的226例院内感染性腹泻患儿的粪便标本进行RV病原检测,并对阳性标本进行分型,调查患儿的临床特征.数据分析分别以构成比、阳性榆出率表示,均值采用t检验.结果 胶体会法RV阳性率为47.8%.院内感染RV腹泻以1岁以内的年龄段最高,新生儿占RV腹泻患儿的32.4%.发病高峰在10、11月份.采用套式-PCR对除新生儿外的67份RV阳性标本进行分型,G3为主要流行的血清型,占46.3%,其次为G1占23.9%、G2占3.0%、G9占1.5%,7份为混合感染,均为G1、G3混合,10份未能分型.从P分型来看,主要流行株为P[8]型,占90.0%,其次为P[4]型占6.0%,3份标本未能分型.未发现P[6]、PE9]和P[10]型.G3P[8]为主要分离株,占61.2%,其次为G1P[8],占17.9%,G1、G3P[8]混合感染占9.5%,G2P[4]、G8P[9]各1例.新生儿32份RV阳件标本中10份成功分型,均为G1P[8].院内感染RV腹泻延长住院天数、增加住院费用.结论 RV是上海地区院内感染性腹泻病的主要病原,其流行的主要血清型为G3P[8]型,但仍需加强监测G1流行株的暴发流行.     

婴幼儿腹泻人群中鼠伤寒沙门菌的流行病学及多重耐药特征研究

目的 了解2014-2018年徐州地区婴幼儿腹泻患者中鼠伤寒沙门菌的流行病学特征和耐药特征,提高对鼠伤寒沙门菌肠炎的流行及耐药性的认识。方法 收集2014—2018年徐州市医院门诊就诊的婴幼儿(0~3岁)腹泻粪便标本,进行沙门菌病原学检测,用描述流行病学方法对鼠伤寒沙门菌的流行特征进行分析。用最低抑菌浓度法测定鼠伤寒沙门菌对常见抗生素的敏感性,用双纸片协同法来确定产超广谱β-内酰胺酶(ESBLs)耐药表型,用PFGE进行分子分型研究。结果 1 343份腹泻标本中检出178株沙门氏菌,其中鼠伤寒沙门菌为72株(5.36%);5年间,沙门菌(χ趋势2=21.23,P<0.01)和鼠伤寒沙门菌检出率呈逐年上升趋势(χ趋势2=16.02,P<0.01);鼠伤寒血清型在沙门菌中的占比为40.45%,亦呈逐年增高的趋势(χ趋势2=18.47,P<0.01)。90.28%的鼠伤寒沙门菌为多重耐药菌,对临床首选儿科用药—头孢他定(25.0%)和头孢曲松(37.50%)的耐药率均高于20%;产ESBLs表型阳性株对氨苄西林/他唑巴坦(χ²=4.57,P<0.05)、头孢吡肟(χ²=38.66,P<0.01)、氨曲南(χ²=45.53, P<0.01)的耐药率高于非产ESBLs表型株。9株多重耐药鼠伤寒沙门菌出现4簇100%一致PFGE带型。结论 近5年,婴幼儿腹泻患者中鼠伤寒沙门菌感染率较高,多重耐药现象严重,存在小范围传播的可能。     

Diarrhea among infants and young children in Canada: a longitudinal study in three northern communities

Diarrhea among neonates and their siblings was studied in 98 families living in Winnipeg, Manitoba, and in 31 native Indian families and in 15 Inuit (Eskimo) families living in isolated settlements in northern Canada. The rate of infection due to rotavirus in neonates was significantly higher and infection occurred more often in the first six months of life in the northern communities (range, 0.36 in Winnipeg to 1.07 in Eskimo Point). No protective effect of breast-feeding was discerned, since infection due to rotavirus occurred more frequently and earliest in neonatal life in Eskimo Point, the community with the highest rate of breast-feeding. In contrast, infection due to Norwalk virus was most common among the neonates of Berens River (0.15 infections per child per year), the only community with relatively unsafe water supplies. Infection due to rotavirus appears to be more frequent in the far North, whereas infection due to Norwalk virus appears to be related more to inadequate sanitation.     

Nebulized flunisolide in infants and young children with asthma: A pilot study

The role of nebulized flunisolide solution in controlling recurrent respiratory symptoms was assessed in a double-blind placebo-controlled parallel study on 23 infants and small children (mean age, 14 2 months) with bronchial asthma. Five of the 12 children in the placebo group and 1 of the 11 patients on active treatment had to be withdrawn from the study. Flunisolide significantly improved symptom scores of wheezing and cough. The rescue treatments with salbutamol did not differ between the two groups during the study. Parents considered the active treatment effective in all the patients, while the placebo was considered useful in 4 of 7 children. No side effects were detected with either treatments. This study indicates that nebulized flunisolide may be an effective treatment for infants with recurrent wheezing and cough. Pediatr Pulmonol. 1996; 21:310–315. © 1996 Wiley-Liss, Inc.     

Immunologic study of the non-pathogenic bacterial flora of the small intestine in children with persistent diarrhea

Twenty five children with diarrhea were studied. Ten children without diarrhea or that had the last episodic one year before biopsy, represented the control group. Jejunal juice and biopsy specimens obtained from each patient were cultured, and bacteria obtained from these were tested against a further piece of mucosa and sample of pure juice from the same patient, to determine the presence within them of antibody against the small bowel bacteria. Duodenal mucosae antibody against non-pathogenic bacteria was demonstrated in 95% of children with diarrhea and only 25% of control group. The immunoglobulin classes involved, IgA and IgM, suggest a strong local immune system stimulation, although a systemic immune response can not be excluded since IgG was frequently found in the mucosa.     

The incidence and the valuation of eaeA gene of enteropathogenic Escherichia coli (EPEC) or aggR gene of enteroaggregative E. coli (EAggEC) in the strains isolated from patients in sporadic diarrhea cases

To clarify the pathogenic role of enteropathogenic Escherichia coli (EPEC) or enteroaggregative E. coli (EAggEC), the possession of eaeA gene of EPEC or aggR gene of EAggEC in the strains isolated from 525 patients in sporadic diarrhea cases during 3 years (1998-2000) in Tama, Tokyo was investigated by a PCR method. The eaeA-positive E. coli strains were confirmed from 23 cases including 5 cases detected verotoxin-producing E. coli (VTEC), and those except VTEC strains (18 cases, 3.4%) were the 5th predominant enteropathogen following rotavirus, Campylobacter, adenovirus, and Salmonella. By age, 17 eaeA-positive cases were from children < 10 years of age, and noticeably, of which 9 were from infants < 24 months of age. On the other hand, although aggR-positive E. coli strains were detected from 11 cases (2.1%), of which 6 also were from infants < 24 months of age. Clinical symptoms of patients whom eaeA or aggR gene-positive E.coli was isolated as the only potential enteric pathogen were similar, showing a mild gastroenteritic features. Only one strain of eaeA-positive E. coli and 4 of aggR-strains were typed with the commercial O-antisera, which were O55, and O86, O111 or O126. In antibiotic sensitivity tests for 9 agents, 22% of eaeA-strains and 91% of aggR-strains showed resistant, especially 10 aggR-strains had resistant to ABPC. These findings suggest that these organisms are a significant causative agents of infantile diarrhea and the PCR method is a useful procedure for the diagnosis of EPEC or EAggEC infectious disease.     

Prevention of antibiotic-associated diarrhea by Saccharomyces boulardii: a prospective study

Saccharomyces boulardii, a nonpathogenic yeast, has been widely used in Europe to prevent antibiotic-associated diarrhea (AAD). We performed a prospective double-blind controlled study to investigate AAD in hospitalized patients and to evaluate the effect of S. boulardii, a living yeast, given in capsule form concurrently with antibiotics. Over 23 mo, 180 patients completed the study. Of the patients receiving placebo, 22% experienced diarrhea compared with 9.5% of patients receiving S. boulardii (p = 0.038). Risk factors found to be associated with AAD were multiple antibiotic combinations (containing clindamycin, cephalosporins, or trimethoprim-sulfamethoxazole) and tube feeding. Clostridium difficile, an anaerobe found in the stools of most patients with pseudomembranous colitis, was variably associated with AAD. We evaluated the role of C. difficile in AAD in the study population and found no significant association between the presence of C. difficile or cytotoxin with AAD. Approximately 33% of the patients without diarrhea harbored at least one C. difficile-positive stool and nearly 50% of these patients had detectable cytotoxin. Similar values were obtained in patients with diarrhea. Of C. difficile-positive patients, 31% (5/16) on placebo developed diarrhea compared with 9.4% (3/32) on S. boulardii; this difference was not statistically significant (p = 0.07). There were no discernable adverse effects of yeast administration. We conclude that S. boulardii reduces the incidence of antibiotic-associated diarrhea in hospitalized patients.     

Acquisition of serum antibody to Norwalk Virus and rotavirus and relation to diarrhea in a longitudinal study of young children in rural Bangladesh

Serum antibodies to Norwalk virus and to rotavirus were measured during longitudinal studies of infectious diseases and nutrition in rural Bangladesh. Initially, the prevalence of antibody to Norwalk virus was 7% in children younger than six months and increased to 80% in children two to five years of age. The incidence of titer increases was highest in one- and two-year-olds and in children who had low or undetectable levels of antibody. Some Norwalk virus infections appeared to result in diarrhea. Nearly all children had serum antibodies to rotavirus at the beginning of the study; however, children with the lowest levels of antibody to rotavirus had the greatest risk of rotavirus diarrhea. Over half of the children had a fourfold increase in titer of antibody to rotavirus during the year, and 7% had increases in two of the three study periods during the year. Most increases in titer of antibody to rotavirus appeared to result from subclinical infections.