Mitchell L. Cohen

Hemorrhagic Colitis Associated with a Rare Escherichia coli Serotype

We investigated two outbreaks of an unusual gastrointestinal illness that affected at least 47 people in Oregon and Michigan in February through March and May through June 1982. The illness was characterized by severe crampy abdominal pain, initially watery diarrhea followed by grossly bloody diarrhea, and little or no fever. It was associated with eating at restaurants belonging to the same fast-food restaurant chain in Oregon (P less than 0.005) and Michigan (P = 0.0005) and with eating any of three sandwiches containing three ingredients in common (beef patty, rehydrated onions, and pickles). Stool cultures did not yield previously recognized pathogens. However, a rare Escherichia coli serotype, O157:H7, that was not invasive or toxigenic by standard tests was isolated from 9 of 12 stools collected within four days of onset of illness in both outbreaks combined, and from a beef patty from a suspected lot of meat in Michigan. The only known previous isolation of this serotype was from a sporadic case of hemorrhagic colitis in 1975. This report describes a clinically distinctive gastrointestinal illness associated with E. coli O157:H7, apparently transmitted by undercooked meat.

Epidemiology of Drug Resistance: Implications for a Post—Antimicrobial Era

In the last several years, the frequency and spectrum of antimicrobial-resistant infections have increased in both the hospital and the community. Certain infections that are essentially untreatable have begun to occur as epidemics both in the developing world and in institutional settings in the United States. The increasing frequency of drug resistance has been attributed to combinations of microbial characteristics, selective pressures of antimicrobial use, and societal and technologic changes that enhance the transmission of drug-resistant organisms. Antimicrobial resistance is resulting in increased morbidity, mortality, and health-care costs. Prevention and control of these infections will require new antimicrobial agents, prudent use of existing agents, new vaccines, and enhanced public health efforts to reduce transmission.

Changing patterns of infectious disease

Despite a century of often successful prevention and control efforts, infectious diseases remain an important global problem in public health, causing over 13 million deaths each year. Changes in society, technology and the microorganisms themselves are contributing to the emergence of new diseases, the re-emergence of diseases once controlled, and to the development of antimicrobial resistance. Two areas of special concern in the twenty-first century are food-borne disease and antimicrobial resistance. The effective control of infectious diseases in the new millennium will require effective public health infrastructures that will rapidly recognize and respond to them and will prevent emerging problems.

Drug-resistant Salmonella from animals fed antimicrobials

It has been difficult to document the postulated sequence of events that begins with the selection of drug-resistant organisms in animals fed subtherapeutic amounts of antimicrobials and ends with clinically important infections in human beings. In early 1983 we identified 18 persons in four Midwestern states who were infected with Salmonella newport that was resistant to ampicillin, carbenicillin, and tetracycline and characterized by a 38-kilobase R plasmid. Twelve of these patients had been taking penicillin derivatives for medical problems other than diarrhea in the 24 to 48 hours before the onset of salmonellosis. Eleven patients were hospitalized for salmonellosis for an average of eight days, and one had a fatal nosocomial infection. We compared plasmid profiles of all human (six-state area) and animal (United States) S. newport isolates over an 18-month period and examined selected records of meat distribution. The results indicated that the patients had been infected before they took antimicrobials, by eating hamburger originating from South Dakota beef cattle fed subtherapeutic chlortetracycline for growth promotion. This study demonstrates that antimicrobial-resistant organisms of animal origin cause serious human illness, and emphasizes the need for more prudent use of antimicrobials in both human beings and animals.

Chloramphenicol-resistant Salmonella newport traced through hamburger to dairy farms. A major persisting source of human salmonellosis in California

Animal-to-human transmission of drug-resistant salmonella and the role of antimicrobial use in food animals in the emergence of these bacteria are controversial subjects. Investigation of a 4.9-fold increase in Salmonella newport isolations from Californians in 1985 showed that 87 percent of the isolates had an unusual antimicrobial-resistance pattern (including chloramphenicol resistance) and a single, identical plasmid. Interviews of 45 patients and 89 matched controls in Los Angeles County showed that illness was associated with penicillin or tetracycline use during the month before onset (P less than 0.001) and with eating ground beef during the week before onset (P = 0.052). The epidemic strain was isolated from hamburger products eaten by cases, abattoirs where the animals from which the meat came were slaughtered, dairies that sent cows for slaughter on days when culture-positive products were processed, and ill dairy cows. Isolation of salmonella from beef carcasses in abattoirs correlated with the proportion of dead or moribund animals received for slaughter (r = 0.60, P less than 0.05). Isolation of chloramphenicol-resistant salmonella from dairy farms was associated with the use of chloramphenicol at those dairies. We conclude that food animals are a major source of antimicrobial-resistant salmonella infections in humans and that these infections are associated with antimicrobial use on farms.

Sporadic Cases of Hemorrhagic Colitis Associated with Escherichia coli 0157:H7

After two outbreaks of hemorrhagic colitis associated with a previously unrecognized pathogen, Escherichia coli O157:H7, a surveillance system was established to identify and study sporadic cases of this distinct clinical illness in the United States. Between August 1982 and April 1984, we identified 28 persons from 11 states who met our case definition and whose stool specimens yielded E. coli O157:H7. Patients ranged in age from 1 to 80 years. Seventeen patients required hospitalization. All patients recovered, although one developed hemolytic-uremic syndrome 7 days after the onset of bloody diarrhea. Detection of E. coli O157:H7 in stools from persons with hemorrhagic colitis was highly associated with collection of stool specimens within the first 6 days after onset of illness. All E. coli O157:H7 isolates produced a Vero cytotoxin. Hemorrhagic colitis caused by E. coli O157:H7 is widely distributed in the United States as a sporadic illness; clinicians should be aware of its distinctive clinical presentation, and should collect specimens promptly when the diagnosis is suspected.

Botulism and botulism-like illness in chronic drug abusers.

From 1982 to 1983 we received reports of a neurologic illness characterized by a symmetric descending paralysis in six drug abusers from widely separated geographic areas. Botulism was confirmed in two patients; type B botulinal toxin was found and Clostridium botulinum was isolated from a small abscess in one, and type A botulinal toxin was found in the serum of the other. The clinical illness in the remaining four patients, although not laboratory confirmed, was also compatible with botulism. None of the patients had histories suggestive of foodborne botulism, and wound botulism was suspected as the cause of illness. There are several reports of tetanus associated with parenteral drug abuse; wound botulism is another toxin-mediated clostridial infection that may occur as a complication of chronic drug abuse.

Antimicrobial resistance: prognosis for public health.

Antimicrobial resistance poses a significant threat to public health worldwide, with certain infections already being untreatable with antibiotics. Increasing resistance is resulting from antimicrobial use coupled with various epidemiological factors that enhance transmission of drug-resistant organisms, and the problem is likely to worsen. Control of antimicrobial resistance is feasible, but will be difficult.

Yersinia enterocolitica Pharyngitis

During the investigation of a large multistate outbreak of milk-borne yersiniosis, 14 patients who presented with pharyngitis had Yersinia enterocolitica isolated from the throat. Their illness was characterized by sore throat and fever without enteritis; 3 needed hospitalization. All patients tested had leukocytosis and an elevated convalescent-phase serum titer against the outbreak strain. In contrast to patients with enteritis, who were children, all patients with pharyngitis were adults. Thus, Y. enterocolitica may be responsible for some sporadic cases of pharyngitis in which the throat culture is negative for other pathogens.

Shigellosis in day care centers: use of plasmid analysis to assess control measures.

Spread of shigellosis within day care centers is difficult to control, and illness may spread into the community. We investigated two sequential outbreaks of diarrhea caused by multiply resistant Shigella sonnei in children at day care centers in 2 neighboring counties in Florida. We used plasmid analysis to identify a single epidemic strain causing both outbreaks and to assess the control measures used. One of the control measures, keeping ill children from attending the center, did not prevent spread of illness in the community.