The risk of acquiring hepatitis from sewage-contaminated water

There is little information on the risk of acquiring hepatitis A from drinking sewage-contaminated water. In a large outbreak of gastrointestinal illness at Crater Lake National Park, Oregon, a US national park, in June-July, 1975, approximately 100,000 persons were exposed to sewage-contaminated water. State health departments reported three cases of Crater Lake-associated hepatitis A for a rate of 12/100,000 per year, comparable to the reported US incidence of non-B hepatitis 10/100,000 per year. Questionnaire survey of 3997 overnight park visitors revealed five cases of hepatitis A, occurring in 2206 persons who drank water but did not receive immune serum globulin (ISG) within two weeks of exposure, an attack rate of 0.23%. The association between drinking park water and subsequently developing hepatitis was not statistically significant. No cases of hepatitis occurred in 320 park staff and family members, repeatedly exposed to contaminated water. The authors do not recommend routine use of prophylactic ISG for similar outbreaks of gastroenteritis caused by sewage-contaminated water but suggest close surveillance of the exposed group, and careful consideration of risk factors and costs.

Community-acquired bacteremia in the elderly: analysis of one hundred consecutive episodes

A retrospective analysis was made of the records of 100 consecutive geriatric patients with community-acquired bacteremia, admitted to a suburban hospital. The most frequently identified tissue sources for these bacteremias were the urinary tract (34 percent), biliary tract (20 percent), and lungs (13 percent). In 11 percent of the patients, the tissue focus was not established. E. coli, Klebsiella species and Streptococcus pneumoniae were the most common organisms isolated, and they contributed to 73 percent of the bacteremias. Of the 100 patients, 26 succumbed to the infection. Clinical manifestations unique to the geriatric patient are described.

Lack of person-to-person transmission of enterotoxigenic Escherichia coli despite close contact

The scanty epidemiologic evidence available suggests that enterotoxigenic Escherichia coli (ETEC) are usually spread by contaminated food and water vehicles; little is known of the risk of secondary spread by contact transmission. Studies carried out in a 22-bed isolation Ward at the U. of Maryland Hospital gave the opportunity to determine whether individuals excreting ETEC, with and without diarrhea, would transmit the pathogen to controls living in close contact. In one combined study, seven volunteers who had ingested 10(8) virulent ETEC (strain H10407), were housed day and night for two weeks with eight other volunterrs participating in an intranasal attenuated influenza vaccine study. In a second study, four persons ingesting 10(8) ETEC (strain 214-4) lived with 13 who were inoculated with intranasal influenza vaccine. The individuals in the E. coli and influenza groups were randomly mixed in bedrooms and shared bathrooms, dining and recreation areas of the ward. Seven persons who ingested ETEC developed diarrhea; all 11 excreted the pathogen (10(7)-10(9) organisms/gm or ml of stool), and 10 had significant rises in anti-O or antitoxin antibody. In contrast, no influenza vaccinees, despite close sharing of facilities, developed diarrhea, excreted ETEC or had rises in antibody to E. coli antigens. These data suggest that ETEC are not readily transmitted to healthy adults by direct person-to-person contact. Precautions to prevent contamination of shared food sources would appear to be the most rational intervention to avoid secondary cases of ETEC diarrhea.

Nosocomial infantile gastroenteritis associated with minirotavirus and calicivirus

A prospective study was carried out to determine the epidemiology and etiology of acute gastroenteritis on the general infant ward of The Montreal Children's Hospital in the late fall of 1976. Diarrhea occurred in 41 of 165 infants (25%), with probable nosocomial acquisition in 26 patients. Two infants each had two episodes of diarrhea, and one had three. A putative pathogen was found in 31 of 45 case episodes (69%). Virus-like particles were present in 28 of 45 patients, and in 24 of 74 asymptomatic room contacts. Particles belonging to six morphologic classes were identified: adenovirus, rotavirus, minirotavirus, calicivirus, picorna-parvovirus, and coronavirus. More than one agent was identified in 12 infants with diarrhea and in five asymptomatic room contacts. No wardwide etiologic pattern was evident, but minirotavirus or calicivirus or both were associated with diarrhea in 20 patients, accompanied by vomiting in 15 of these infants. Moreover, spread of individual agents was almost entirely limited to minirotavirus and calicivirus, with diarrhea in six of ten, and four of seven, virus positive room contacts, respectively. These viruses were also identified in stools from 12 infants without diarrhea, seven of whom had repeated vomiting. Data support the etiologic role of minirotavirus and calicivirus in diarrhea or vomiting or both in hospitalized infants.

Epidemiology of Escherichia coli in the United States

Current evidence suggests that diarrheagenic E. coli are not important causes of disease in the sanitized urban centers of the United States at this time. However, enterotoxigenic E. coli are a leading cause of diarrhea among travelers who visit developing countries. The failure of diarrheagenic E. coli pathogens to gain a foothold in this country, despite problems with enteropathogenic E. coli in nurseries during the 1940s and 1950s and the more recent multiple introductions of enterotoxigenic E. coli by travelers returning from developing areas of the world, demonstrates the epidemiologic impotence of diarrheagenic E. coli in the relatively sanitized environment of the United States. Nondiarrheagenic E. coli seem to be major pathogens in community-acquired and nosocomial infections in extraintestinal sites.

Studies into the incidence of carriers of enteropathogenic E. coli

Enteropathogenic Escherichia coli (EPEC) is frequently found in asymptomatic carriers. When checked over a period of two and a half months at fortnightly intervals, nine out of 20 children at a child care centre in Jamaica showed EPEC of three different serotypes in faecal smears. Four stool specimens were found to be positive in another 45 children, controlled routinely on admission to a district hospital in Jamica. None of either group had diarrhoea at the time of collection. These results confirm that serotypes should not be equated with pathogenicity. Also, current methods of detecting enterotoxin are too time-consuming and impractical for non-specialized laboratories. The place of antibiotics in EPEC diarrhoea is criticized. Initial control measures should centre on fluid and electrolyte replacement irrespective of the aetiology of the diarrhoea.

[Cross-infection during scalding and plucking of broiler chickens (author's transl)]

In two poultry-processing plants, experiments were carried out to detect cross-infection during scalding and plucking of broiler chickens. These trials showed that cross-infection was only detectable when experimental infection with the indicator micro-organism Escherichia coli K12 was applied externally to the broiler chickens. When infection was applied internally, only a small degree of transmission was observed. Indicator micro-organisms applied externally to broiler chickens prior to scalding and plucking, were present on the cooled product in larger numbers than those applied internally in the intestines of broilers. The number of carcasses which were positive after cooling was found to have decreased in poultry-processing plant B compared with the situation after plucking, whereas this number was not affected to any appreciable extent in processing plant A.

The acquisition of Escherichia coli by new-born babies

In discussing the background of these studies the importance of faecal carriage of Gram negative organisms by hospital patients is stressed. In many instances it was shown that transmission is by an oral route. This discussion leads on to an assessment of the dose required for Escherichia coli to implant in the bowel. The difficulties of studying the spread of E. coli within a faecal specimen are discussed. A number of papers are quoted which show that E. coli are present in the vagina of women and that the acquisition of these E. coli by babies is related to the length of time that the birth takes, and that there is a relationship between the E. coli found in the faeces of the mothers, the mucus swallowed by the babies at birth and subsequently in the faeces of the babies. Most of the eralier studies quoted deal predominantly with enteropathogenic serotypes, but it was later shown that other serotypes can be similarly acquired by the babies. Although this appears to be the general method by which babies acquire their faecal E. coli, it is well established that they can also be obtained from the environment, hence ward outbreaks of infantile gastroenteritis. Studies on normally delivered babies show that generally two thirds obtain their faecal E. coli from their mothers while the rest appear to pick up environmental strains. Very detailed biochemical and serological studies need to be performed to assess this. Caesarian section babies are generally not likely to become colonized by their mothers' faecal E. coli and studies are described which show that the babies faeces or rectal swabs are usually the first areas colonized and that the E. coli are spread from there. Extensive environmental studies suggest that contaminated hands and uniforms of the nursing staff may be the main vector for transmitting E. coli. There is a wide variety of E. coli serotypes present in a maternity ward at any time and these are related to the presence of the babies excreting them. A variation in the ability of strains to spread was noted.

[Influence of restrictive use of antibiotics on the development of drug resistance in intestinal Escherichia coli from pigs (author's transl)]

A retrospective investigation into the drug resistance pattern of intestinal E. coli was carried out in 17 closely monitored herds in order to evaluate a possible influence of an improved diagnostic and a restrictive use of antibiotics in swine herds. The herds participated from October, 1970, in an investigation of preweaning mortality and morbidity, and during a two-year investigation period antibiotics were only used when therapeutically indicated. Sensitivity tests were regularly performed on the intestinal flora from post mortem examined pigs from the herds and the results forwarded to the local veterinarians. A total of 443 E. Coli strains were isolated in pure or almost pure culture from the jejunum of post mortem examined pigs and tested for sensitivity, using the following antibiotics: streptomycin, compound sulphonamide, neomycin, oxytetracycline, chloramphenicol, nalidixic acid, furazolidone, and ampicillin. During the investigation period, the frequency of isolated multiresistant E. coli strains decreazed from 67.7 per cent to 9.5 per cent and the number of strains without antibiotic resistance increased from 3.0 per cent to 36.2 per cent (Table I; Fig. 1). Herds were divided into 3 groups according to different intensity of antibiotic administration and to closed or open management system (Table II). The most pronounced decrease in the number of multiresistant E. coli strains (from 64.9 to 2.0 per cent) was observed in Group I, which comprises closed herds with a rapid decrease in the use of antibiotics. In Group II, which comprises semi-closed herds with a decreasing, but in the last year of the investigation still frequent use of antibiotics, a somewhat slower decrease of the number of multiresistant strains to a level of 12.1 per cent was observed. The number of strains without resistance increased to approximately the same level as in Group I. In Group III, which comprises open herds with infrequent use of antibiotics, the incidence of resistant E. coli strains fluctuated (Table III; Fig. 2). The resistance was proved transferable in 60.5 per cent of the examined resistant strains. The frequency of transferability did not show any significant change during the investigation period (Table IV). The most frequently encountered resistance determinants were: sulphonamide (97 per cent), streptomycin (40 per cent), and oxytetracycline (34 per cent). Only resistance against sulphonamide, streptomycin, tetracycline, and chloramphenicol was proved transferable (Table V). It is concluded that it is possible to obtain a simultaneous reduction of induced antibiotic resistance of intestinal E. coli and of enteric diseases in sucking pigs in commercial herds, by adjustment of management and rational use of antibiotics based on improved diagnostic including in vitro sensitivity tests.

[Comparative importance of different transmission factors in the spread of acute intestinal infections]

The authors generalized literature data on a comparative epidemiological significance of individual ways of transmission in the spread of escherichiasis, shigelloses, salmonelloses and cholera. Resistance of the corresponding causative agents to the factors of external environment and the action of gastric juice were considered. Data on concentrations of different enteropathogenic agents in the feces of patients, convalescents and healthy carriers were compared with the observations on doses causing the disease in man. On the basis of analysis a conclusion was drawn on a different significance of water, food and domestic ways of infection in the spread of various etiological forms of acute intestinal infections.