Campylobacter enteritis: clinical and epidemiologic features

Evidence for an efflux pump in multidrug-resistant Campylobacter jejuni

Mechanisms of drug resistance in Campylobacter jejuni were investigated. Mutant strains 34PEFr, which was resistant to pefloxacin (128-fold increase in the MIC), and 34CTXr, which was resistant to cefotaxime (32-fold increase in the MIC) and which was derived from the susceptible parent 34s, were obtained by serial passages on pefloxacin and cefotaxime gradient plates, respectively. Both mutants showed cross-resistance to erythromycin, chloramphenicol, tetracycline, beta-lactams, and quinolones. While the quinolone resistance of strain PEFr could be explained by a mutation at codon 86 of the gyrA gene, the multidrug resistance phenotype of both strains was further investigated. Accumulation of pefloxacin, ciprofloxacin, and minocycline was measured by fluorometry and was found to be lower in the mutant strains than in the parent strain. Preincubation of the cells with carbonyl cyanide m-chlorophenylhydrazone, however, completely abolished this difference. Analysis by sodium dodecyl sulfate-polyacrylamide gel electrophoresis of outer membrane preparations from both mutant strains showed overexpression of two proteins of 55 and 39 kDa which were absent from the outer membranes of the wild-type strain. These results indicate that in C. jejuni 34PEFr and 34CTXr, multidrug resistance is associated with an efflux system with a broad specificity.

DNA diversity among isolates of Campylobacter jejuni detected by PCR-based RAPD fingerprinting

A PCR-based randomly amplified polymorphic DNA method was used to amplify Campylobacter jejuni DNA using a single oligonucleotide primer derived from either a homologous source or from Mycoplasma gallisepticum. The method was able to detect the heterogeneity of amplified DNA from human, chicken and turkey sources and can be used as a tool to study the epidemiology of Campylobacter jejuni infection.

Culture media for the isolation of campylobacters

The history of the development of selective media for isolation of campylobacters, including the rationale for choice of selective agents is described. Developments have included modifications to allow incubation at 37 degrees C instead of 42 or 43 degrees C and changes in the types and concentrations of antibiotics in order not to inhibit organisms such as Campylobacter upsaliensis, C. jejuni subsp. doylei and some strains of C. coli and C. lari. When examining foods, plating media originally developed for isolation from faeces are normally used, sometimes after liquid enrichment. Most of the media include ingredients intended to protect campylobacters from the toxic effect of oxygen derivatives. Most commonly used are lysed or defibrinated blood; charcoal; a combination of ferrous sulphate, sodium metabisulphite and sodium pyruvate (FBP); and haemin or haematin. To date no medium includes an indicator system--for instance a pH indicator to show whether colonies produce acid or alkali from particular substrates. The manner in which liquid enrichment media are used has been modified for food samples to avoid inhibitory effects on sublethally damaged cells by toxic components in the formula. This is done by a preliminary period of incubation at reduced temperature and sometimes by delayed addition of antibiotics. Expensive and time-consuming methods have been proposed to achieve a microaerobic atmosphere while using liquid enrichment media. To date there is no generally accepted 'standard' method of isolating campylobacters from food.

Detection of alpha- and beta-hemolytic-like activity from Campylobacter jejuni

Alpha-hemolytic-like activity from Campylobacter jejuni was clearly apparent when the medium pH ranged from 6.0 to 6.5, but the hemolytic zones disappeared when the pH of the medium increased. Beta-hemolytic-like activity just beneath the bacterial growth appeared after prolonged incubation. The hemolytic activity was not influenced by the species of blood.

Infectious diarrhoea in children: controlling transmission in the child care setting

An increase in the number of preschool children cared for within groups in child care centres has been associated with increasing numbers of women in the workforce. Children at this age are at high risk for gastrointestinal diseases caused by a large number of enteric pathogens, and the risk is increased by the greater potential for person-to-person transmission within group care. This report considers the pathogens that may cause diarrhoeal illness in children, with particular reference to those that have been reported in formal day care settings. The major risk factors for transmission of these agents and a high rate of diarrhoeal illness in the child care setting include attendance of non-toilet-trained children, staff combining nappy changing and food preparation duties, large enrollment, low staff-to-child ratio, and poor hygiene and child handling practices. Investigations undertaken during an outbreak of diarrhoea have frequently used limited diagnostic testing, often suitable for identifying only bacterial and protozoal agents. Such limited investigations have tended to incriminate agents that have prolonged carriage and are easily identifiable in standard microbiology laboratories. Finding a pathogen in these circumstances needs to be interpreted with caution. Prevention and control measures include training and education in good personal hygiene, emphasis on the need for frequent handwashing, separation of change areas from food handling and eating areas, routine cleaning and disinfection of environmental surfaces and personal items, and exclusion of any child or child care worker with diarrhoea.

Comparison of pivmecillinam and nalidixic acid in the treatment of acute shigellosis in children

The efficacy of oral pivmecillinam was compared with nalidixic acid in the treatment of acute shigellosis in children 1-8 years of age. In a double-blind trial we studied 80 comparable children with bloody diarrhoea of less than 3 days' duration. Shigella spp. was isolated in 71 children. Patients were randomly assigned to receive either pivmecillinam, 50 mg/kg.day, or nalidixic acid, 60 mg/kg.day, both given orally for 5 days. The stool frequency decreased progressively in both treatment groups. Nalidixic acid failed to eradicate Shigella species in 10 patients, compared with three in the pivmecillinam group (p = 0.04). Similarly, clinical failure was observed in 11 of 37 patients receiving nalidixic acid and in 2 of 26 patients infected with nalidixic acid-susceptible strains as against none in the group receiving pivmecillinam. The results suggest that pivmecillinam given orally was, in fact, more effective than nalidixic acid in the treatment of acute shigellosis in children, particularly when the resistant strains are taken into account.

Culture of colonoscopically obtained biopsy specimens in acute infectious colitis

To investigate the value of colonoscopy in the diagnosis of acute infectious colitis, we prospectively cultured both feces and biopsy specimens obtained during colonoscopy of patients who, because of clinical features such as the acute onset of abdominal pain and diarrhea, were suspected of having the disease. Of the 20 patients who participated in the study, some causative micro-organism was identified in 13 (Campylobacter in 6 patients, Salmonella in 5 patients, and Yersinia in 2 patients), but not in the remaining 7. In addition, biopsy specimens were more sensitive for culture (positive for Campylobacter in 4 patients, Salmonella in 5 patients, and Yersinia in 1 patient) than were feces samples (positive for Campylobacter in 2 patients and for Yersinia and Salmonella in 1 patient each) (50% versus 20%, p = 0.048). These findings suggest that cultures of biopsy specimens obtained during colonoscopy may be diagnostic in sporadic cases of acute enterocolitis caused by bacteria.

Campylobacter jejuni enterocolitis causing peritonitis, ileitis and intestinal obstruction

Patients with Campylobacter enterocolitis may come to laparotomy due to the severity of abdominal symptoms and signs, although only two patients with intestinal inflammation have been described and in neither was the histopathology documented. A case of a 52-year-old male who had a typical diarrhoeal illness of Campylobacter enterocolitis diagnosed on stool culture is reported. Despite appropriate treatment he developed signs and symptoms consistent with small intestinal obstruction. Laparotomy revealed peritonitis and thickened distal ileum with transmural inflammatory changes on histopathology. These changes were shown to have completely resolved at a second laparotomy, required for persistent obstruction due to adhesions. Recurrent adhesions culminated in a third laparotomy. The clinical, operative and histopathological findings may be confused with Crohn's disease.

Arcobacter (Campylobacter) butzleri-associated diarrheal illness in a nonhuman primate population

After DNA hybridization identified an isolate from an ill rhesus macaque (Macaca mulatta) as Arcobacter (Campylobacter) butzleri, we initiated a study to determine whether A. butzleri was associated with diarrheal disease in nonhuman primates at the Yerkes Primate Research Center. By using Campy-CVA medium incubated at 35 degrees C, 15 A. butzleri isolates were obtained from 14 macaques; 7 macaques were coinfected with Campylobacter coli and Campylobacter jejuni. A. butzleri was not isolated from normal feces, despite the fact that feces from 76 macaques were cultured at necropsy. Histologic evaluation of colonic specimens from three macaques from which A. butzleri had been isolated showed mild to moderately severe chronic, active colitis. Ribotype analysis of the 15 A. butzleri isolates revealed nine different strains; these data suggest that A. butzleri may be endemic in this primate population and that a point source of infection is unlikely. This is the first report of the presence of A. butzleri in juvenile and adult macaques with diarrhea, and it may present an opportunity to study the pathogenesis of this organism, which appears to be associated with persistent diarrhea in humans.

Sub-gingival microflora in Macaca mulatta species of rhesus monkey

The Macaca mulatta species of rhesus monkey is one of several non-human primate (nhp) models for periodontal disease. This report presents the bacteriology of the gingival sulci in M. mulatta monkeys. Three sub-gingival sites (maxillary right central incisor, the disto-buccal of the mandibular left second molar and mesio-buccal of the mandibular right second molar) of 9 monkeys were evaluated clinically before scaling and 7 days after scaling. Plaque samples were obtained from sub-gingival sites before clinical examination and studied bacteriologically by dark field microscopy, selective and non-selective culture, and by primary phenotypic characterizations of culture isolates. Several gingival sites presented with mild gingival inflammation. Anaerobic and facultatively anaerobic bacteria were the predominant flora colonizing the gingival sulci. The major microbial groups were Haemophilus species (100% of sites; percentage of total anaerobic count (TAC): 21-51), Peptostreptococcus micros (89%, 7.5-29.5), Actinomyces sp. (85%, 7-27), Fusobacterium nucleatum (90%, 5-8), Actinobacillus actinomycetemcomitans (73%, 1.3-12), black-pigmented anaerobic rods (BPAR) (80%, 0.6-6.5) and oral streptococci (80%, 0.2-1.0). Microbial groups detected less often were Wolinella sp. (66%, 0-2.6), Capnocytophaga sp. (30%), Eikenella corrodens (4.7%, 0), Campylobacter sp. (28%, 0-0.1) and spirochetes (4.7%, 0-0.07). Seven days after gingival sites were scaled, the plaque score and indices for gingival inflammation declined significantly. The gingival flora after scaling were characterized by lower proportions of the Actinomyces sp., P. micros and BPAR; and increased proportions of the oral streptococci, relative to pre-scaling levels.(ABSTRACT TRUNCATED AT 250 WORDS)

Characteristics of the internalization and intracellular survival of Campylobacter jejuni in human epithelial cell cultures

The characteristics associated with the internalization and intracellular behavior of Campylobacter jejuni during short-term and long-term cultivation with INT 407 cells were examined. The internalization of C. jejuni by INT 407 cells was inhibited by cytochalasin dansylcadaverine, chemicals that disrupt microfilament formation and inhibit receptor cycling, respectively. Ammonium chloride and methylamine, two chemicals that inhibit endosomal acidification, did not affect C. jejuni internalization. Once internalized, C. jejuni were found exclusively with membrane-bound vacuoles. With regard to intracellular survival, a decline in the number of viable intracellular bacteria, as determined by protection from gentamicin, occurred during the initial phase of infection and when a low level of the antibiotic was maintained in the culture medium. However, the number of intracellular C. jejuni increased markedly after the removal of the antibiotic. In the absence of antibiotic, the infection led to the deterioration of the cell monolayers, indicating that C. jejuni is able to survive within epithelial cells and elicit a cytotoxic effect. The ability of C. jejuni to enter and exert deleterious effects on cells may reflect a pathogenic mechanism associated with enteritis caused by this organism.

Altered synthetic response of Campylobacter jejuni to cocultivation with human epithelial cells is associated with enhanced internalization

Campylobacter jejuni has been shown to bind to and enter epithelial cells in culture. The interaction of C. jejuni with INT 407 epithelial cells was examined to determine whether bacterial protein synthesis is required for either binding or internalization. Chloramphenicol, a selective inhibitor of bacterial protein synthesis, significantly reduced the internalization, but not binding, of C. jejuni compared with untreated controls as determined by protection from gentamicin. Electrophoretic analysis of metabolically labeled proteins revealed that C. jejuni cultured with INT 407 cells synthesized 14 proteins that were not detected in organisms cultured in medium alone. The inhibitory effect of chloramphenicol on internalization was reduced by preincubation of C. jejuni with INT 407 cells. The results indicate that C. jejuni, like some other enteric pathogens, engages in a directed response to cocultivation with epithelial cells by synthesizing one or more proteins that facilitate internalization and suggest that this phenomenon is relevant to the pathogenesis of enteritis caused by C. jejuni.

The effect of lactic acid sprays on Campylobacter jejuni inoculated onto poultry carcasses

Spraying poultry carcasses with 1% lactic acid 10 min after inoculation with Campylobacter jejuni, resulted in a significant reduction in the number of the bacteria after 4 h at 4 degrees C. Some of the inoculated cells, however, survived for at least 144 h. Spraying 10 min after inoculation with 2% lactic acid, totally eliminated all inoculated C. jejuni within 24 h. On the other hand, spraying 24 h after inoculation, with either 1% or 2% lactic acid did not eliminate all the bacteria. Inoculated C. jejuni on poultry carcasses not sprayed with lactic acid, survived at 4 degrees C throughout the sampling period (up to 144 h) and showed little tendency to decrease in number even when the carcasses started to deteriorate. Resident campylobacters on poultry carcasses were significantly reduced by the lactic acid treatment. Frozen and thawed chickens appeared to show a graying of the skins immediately after spraying with lactic acid, slightly stronger with 2% lactic acid, but the colour reverted to normal after 24 h. We were not able to observe any colour change on the fresh broiler chickens after lactic acid treatment. Our results indicated that lactic acid had a significant bactericidal effect on C. jejuni on both naturally and artificially contaminated poultry carcasses. This effect, however, became manifest only several hours after acid treatment.

Comparison of six commercially available transport media for maintenance of Serpulina (Treponema) hyodysenteriae

Two anaerobic (A1 and A2), 1 selective (S1), and 3 conventional (C1, C2, and C3) transport media formulations were compared for their capacity to maintain the viability of Serpulina (Treponema) hyodysenteriae. Initial experiments compared the recovery of S. hyodysenteriae from pure cultures held in each transport medium for 0.5, 1, 2, 3, 5, and 7 days at -40 C, 4 C, 25 C, and 36 C. Subsequent experiments compared each transport medium for maintenance of S. hyodysenteriae in fecal specimens obtained from experimentally infected pigs after holding for up to 7 days at 25 C. In each experiment, the viability of S. hyodysenteriae in each transport medium incubated at each temperature and for each period was determined by inoculating the transport medium onto either trypticase soy agar with 5% sheep blood or selective BJ agar and incubating at 42 C anaerobically. Viability and fecal flora contamination were evaluated blindly after 2-, 4-, and 6-day incubation periods. At -40 C, recovery of viable S. hyodysenteriae from pure culture did not differ among the transport media from 0.5 to 7 days, and all of the transport media consistently maintained the viability of the spirochetes for 7 days. At 4 C, the anaerobic and selective transport media maintained the viability of pure cultures of S. hyodysenteriae significantly better than did the conventional transport media group at day 7 (P = 0.019). At the same temperature, the anaerobic media maintained viability better than did the conventional media at 5 days (P less than 0.042).(ABSTRACT TRUNCATED AT 250 WORDS)

A review of hospitalized patients with bacterial gastroenteritis

The distribution and clinical management of thirty-two hospitalized patients with salmonella and campylobacter infections were reviewed and the impact of these infections on hospital resources was assessed. Eighteen patients with salmonella infection had an age and sex distribution comparable with the community cases. In contrast, 10 out of 14 (71.4%) patients with campylobacter infection were under 20 years of age though the peak incidence of the infection in the community occurred in the 21-65 years age group (67%). There was no male predominance. The median duration of stay in hospital was 6 days for patients with salmonella infection and 3 days for those with campylobacter infection. Physicians were inconsistent in the treatment of campylobacter infection. Overall the financial impact of managing patients with salmonella and campylobacter infection was considerable (1384 pounds and 779 pounds respectively per patient). A limitation on unnecessarily prolonged hospital stays and the establishment of clear guidelines for the clinical management of these infections are necessary.

In vitro susceptibilities of aerotolerant Campylobacter isolates to 22 antimicrobial agents

We evaluated the in vitro activities of 22 antimicrobial agents against 78 human and animal isolates belonging to two aerotolerant Campylobacter species, C. cryaerophila and C. butzleri, using a broth microdilution technique. An additional 10 antimicrobial agents were included at concentrations found in selective Campylobacter media. Strains of C. cryaerophila belonged to two DNA hybridization groups: DNA hybridization group 1A, which includes the type strain of C. cryaerophila, and DNA hybridization group 1B. The aminoglycosides, fluoroquinolones, and one tetracycline (minocycline) demonstrated the most activity against all DNA hybridization groups (C. cryaerophila DNA groups 1A and 1B and C. butzleri). Most isolates were resistant to cephalosporin antibiotics, with the exception of cefotaxime, and were variably susceptible to trimethoprim-sulfamethoxazole. C. cryaerophila DNA hybridization group 1A isolates were generally susceptible to the tetracyclines, chloramphenicol, nalidixic acid, azithromycin, erythromycin, and roxithromycin and moderately susceptible to clindamycin, trimethoprim-sulfamethoxazole, ampicillin, and ampicillin-sulbactam. The MICs of tetracyclines were higher for C. butzleri and C. cryaerophila DNA hybridization group 1B isolates than for C. cryaerophila DNA hybridization group 1A isolates, but most strains were still susceptible to doxycycline and tetracycline; all isolates were susceptible to minocycline. C. butzleri and C. cryaerophila DNA hybridization group 1B isolates were generally resistant to the macrolide antibiotics (including erythromycin), chloramphenicol, clindamycin, nalidixic acid, ampicillin, and trimethoprim-sulfamethoxazole. Differences in antimicrobial susceptibility between aerotolerant Campylobacter species and more common Campylobacter species, e.g., C. jejuni, suggest that different treatment strategies may be necessary. Strains of all three DNA hybridization groups of aerotolerant Campylobacter isolates were susceptible to colistin, polymyxin B, and rifampin at concentrations commonly used in selective media. These results suggest that primary isolation methods for Campylobacter species may need to be modified to include aerotolerant Campylobacter strains.

Campylobacter species as a cause of diarrhoea in children in Calcutta

From 1985 to 1988, 857 children (aged between 1 day and 60 months) admitted to hospital with diarrhoea and 241 controls (aged between 5 days and 60 months) were examined for campylobacters and other enteric pathogens by means of conventional methods. The difference between the isolation rates of campylobacters in those cases in which no other enteric pathogen was found (4.8%) and controls (6.2%) was not significant (P greater than 0.05). Strains of Campylobacter jejuni/coli were isolated throughout the year with higher isolation rates during the summer and monsoon months. Mixed infections were very common. Watery diarrhoea (97.6% cases) was the most common clinical presentation of patients found to be infected solely by C. jejuni/coli. Most patients infected with campylobacters were mildly to moderately dehydrated. Biotype I of C. jejuni and C. coli was the dominant biotype associated with cases and controls. All strains of C. jejuni/coli, regardless of their source, were found to be sensitive to erythromycin. From this study, it appears that enteric infections with campylobacters among children in Calcutta are common but often asymptomatic.

Recovery of injured Campylobacter jejuni cells after animal passage

Sixteen freeze-thaw-injured nonculturable stocks of Campylobacter jejuni were passed through rat gut, and seven were reisolated. These reisolated strains were converted to toxin producers, as they were before preservation, following consecutive passages through rat gut. This observation indicated the existence of an injured, viable, but nonresuscitated form of C. jejuni which can be resuscitated to a culturable and fully virulent form by passaging the organism through a susceptible host.

Campylobacter fetus subspecies fetus infection

During a six-year period five patients with Campylobacter fetus subspecies fetus infections were seen at the Mayo Clinic in Rochester, Minnesota. Bacteremia was observed in two patients, one presenting with aortic valve endocarditis and the other with abdominal atherosclerotic aortic aneurysm. C. fetus subsp. fetus was isolated from tibial tissue of a patient with osteomyelitis. Diarrhea was the main complaint of two further patients, and was also mentioned by the patient with the aortic aneurysm. Despite the use of incubation conditions and selective media geared to detect only Campylobacter jejuni, C. fetus subsp. fetus was isolated from stool specimens of the two patients with gastrointestinal symptoms. The fact that three of five C. fetus subsp. fetus infections observed in this study were associated with intestinal symptoms further supports the importance of the gastrointestinal tract in the pathogenesis of C. fetus subsp. fetus infections.

Epidemiology of campylobacteriosis in a cohort of rural population near Calcutta

Over a 2-year period, 25 families comprising of 181 individuals of all ages were longitudinally observed for the excretion of Campylobacter species. Faecal samples were taken from all persons with diarrhoea. Specimens were also taken from apparently healthy individuals and from domestic animals living within the confines of the study families at monthly intervals. The overall diarrhoea attack rate was 19 episodes per 100 person-years with peak incidence in the 1- to 4-year-old age group (76/100 person-years). Eight (11.5%) of the total episodes were campylobacter-associated and the overall rate of campylobacter positive diarrhoeal episodes were 2.2 per 100 person-years. Of the 1002 stool samples from healthy individuals 32 (3.2/100 samples) were positive for campylobacter. The organism was most frequently isolated from children under 1 year of age both during diarrhoeal episodes (11.5 per 100 person-years) and non-diarrhoeal (11.1 per 100 samples). Multiple infections in a family were rare. In 19.4% of the occasions one or more animals were campylobacter positive. However, only in 7.7% of these occasions was a human infection recorded within 1 month after the animal was found to be positive. The study showed that the epidemiology of campylobacteriosis in this community was distinct compared to that observed in developed countries.

Waterborne transmission and the evolution of virulence among gastrointestinal bacteria

Diarrhoeal diseases are primary contributors to millions of deaths annually. Yet, little is known about the evolutionary reasons for the differences in virulence among gastrointestinal pathogens. Applying the comparative, cost/benefit approach of evolutionary biology this paper proposes that waterborne transmission should favour evolution towards high virulence. This hypothesis is supported by a cross-specific test, which shows that waterborne transmission is strongly correlated with the virulence of bacterial gastrointestinal pathogens of humans. Alternative explanations of this correlation are not supported by available data. These findings bear on public health policy because they draw attention to a previously unrecognized long-range benefit gained from purification of water supplies; diarrhoeal pathogens may evolve to lower levels of virulence.

Modification to the RITARD surgical model

The Removable Intestinal Tie-Adult Rabbit Diarrhea (RITARD) procedure is the surgical model of choice for studying pathogenesis of diarrheas of Campylobacter, Escherichia coli, and Aeromonas origin. Other than nonhuman primates, the RITARD rabbit is the only model that closely resembles human infection. Classically, the RITARD model is created by isolating the terminal ileum using umbilical tape placed in a slipknot fashion, and injecting the occluded segment with the organism of choice. The slipknot is removed at 4 h postinoculation and patency of the gut reestablished. We found removal of the umbilical tape to be extremely difficult, usually requiring a second surgery to gently untie the material and prevent destruction of the fragile intestinal tissue. This complication of the described procedure appeared to be related to the absorptive and abrasive nature of the tape material. The modification described uses the same idea, but a different material and a different knot pattern. The tubing was easily removed at the prescribed 4 h postsurgery, without an additional surgery. The tubing did not adhere to or damage the gut, yet did provide the occlusive seal required for a 4-h static gut. Histologically, no evidence of pressure could be found at the tie site.

Septicaemia caused by unusual Campylobacter species (C. laridis and C. mucosalis)

Two cases of campylobacter septicaemia are described. The first, caused by Campylobacter laridis was associated with gastroenteritis and occurred in a healthy individual. In the second case, a catalase negative species, C. mucosalis was isolated from blood in an immunocompromised patient with symptoms of pneumonia. Both campylobacter strains grew faintly under the routine culture conditions used. Improved diagnostic procedures for Campylobacter species may thus be warranted.

Sexually transmitted causes of gastrointestinal symptoms in homosexual men

The possible etiologic agents that may cause gastrointestinal complaints in homosexually active men are multiple, and their diagnosis is complex. This article presents a logical approach to the work-up and diagnosis of gastrointestinal complaints in homosexually active men and to discuss their treatment and disease intervention.

Infectious diarrhea. Managing a misery that is still worldwide

Infectious diarrhea is the largest single cause of morbidity and mortality in the world. Bacteria, viruses, and protozoan parasites are the most common causative agents. Treatment in most cases of bacterial and viral diseases consists of correcting fluid loss and electrolyte imbalance by oral or parenteral rehydration. Antimicrobial therapy is reserved for very ill patients only. With the exception of Cryptosporidium, for which no effective agent is yet available, all protozoan infections are treatable with metronidazole.

Infectious enteritis. A collective review

Enteric infections are a major cause of diarrhea in the United States. Pathogens can cause diarrhea by elaboration of toxins that affect the intestinal mucosa or by direct invasion of the intestinal wall. Clinical evaluation can provide important clues to aid in establishing a correct diagnosis in most patients with infectious enteritis. Appropriate cultures are necessary to confirm the diagnosis in most cases. Most types of infectious enteritis are self-limiting, but some pathogens can cause serious disease, requiring accurate diagnosis and suitable antibiotic therapy. Appropriate precautions are mandatory to prevent the spread of infectious diarrhea from occurring in the hospital environment. Dietary restrictions and appropriate hygiene should be observed during travel to foreign countries to reduce the chance of acquiring infectious enteritis.

Bismuth subsalicylate in the prevention of colonization of infant mice with Campylobacter jejuni

Infant mice were used for the evaluation of the efficacy of bismuth subsalicylate (BSS) in the prevention of the growth of Campylobacter jejuni in the intestine. The MIC90 of ten C. jejuni strains was 900 micrograms/ml. Of three dosage regimens tested, continuous treatment before and after the bacterial challenge, mimicking the way BSS is used in the prevention of traveller's diarrhoea, was the most effective. Growth inhibition was dose dependent; the high dose of 2000 micrograms per day was more effective than 300 micrograms per day. After cessation of treatment, campylobacter counts increased to the same level as in the control animals.

Isolation, characterization, and host-cell-binding properties of a cytotoxin from Campylobacter jejuni

A 68,000-molecular-weight protein was isolated by polyacrylamide gel electrophoresis from the organism-free filtrate of a fully virulent clinical strain of Campylobacter jejuni. The eluted protein was heat labile, was inactivated at either pH 3.0 or 9.0, was sensitive to trypsin, and was lethal for fertile chicken eggs. It also had toxic effects on chicken embryo fibroblast, Chinese hamster ovary (CHO), and intestinal 407 (Int407) cells. A monoclonal antibody (CETPMAb4) raised to this eluted toxic protein (ETP) from C. jejuni abolished these toxic activities. Homology between C. jejuni ETP and Vibrio cholerae toxin was not observed in that specific antisera to each did not block their respective toxic activities. In enzyme-linked immunosorbent assays, ETP, unlike chlorea enterotoxin, did not bind to GM1 ganglioside. Furthermore, the C. jejuni toxin had cytotoxinlike properties and induced rounding of CHO cells. Binding of ETP to Int407 and primary chicken embryo fibroblast cells was maximal after 2 h as assessed by enzyme-linked immunosorbent assay, and this toxin adherence to host cell membranes was significantly reduced by prior treatment of the cells with proteolytic enzymes, neuraminidase, or glutaraldehyde but not by treatment with beta-galactosidase, lipase, Nonidet P-40, or sodium metaperiodate. In competitive binding assays, sugars, lectins, or GM1 ganglioside did not adversely influence uptake of ETP by these cells. These results suggest that the ETP produced by C. jejuni is a cytotoxin which binds to Int407 cells via a protein- or glycoproteinlike receptor on cell membranes and possesses properties dissimilar to those of V. cholerae toxin.

Microbiological quality and safety of zoo food

Two types of commercial products for feeding zoo animals (a frozen meat product, referred to as zoo food, and a dry product, referred to as dry food) were microbiologically examined for spoilage organisms (aerobic, psychrotrophic, coliform, Escherichia coli, mold, and yeasts) and pathogens (Salmonella spp., Listeria monocytogenes, and Campylobacter jejuni). Levels of microorganisms in frozen ground zoo food were compared with those in frozen ground beef and frozen ground turkey meat. The level of microbial contaminants in frozen ground zoo meat was found to be similar to that in frozen ground beef and higher than that in frozen ground turkey meat. Sixty percent of the frozen zoo meat samples were Salmonella positive, and all of the samples were L. monocytogenes positive. Dry zoo food was documented to have microbial levels lower than those in frozen zoo meat; the pathogen levels were less than 1/25 g of food. Defrosting zoo meat at 10, 25, and 37 degrees C for 24 h showed that 10 degrees C is the best temperature for defrosting frozen ground zoo meat loaves (length, 9 in. [22.8 cm]; radius, 2 in. [5.1 cm]) without affecting the microbiological quality or safety of the product.

Immune response to Campylobacter jejuni and Campylobacter coli in a cohort of children from birth to 2 years of age

A cohort of 111 children from Bangui, Central African Republic, was surveyed for enteric Campylobacter infections from birth to the age of 2 years; stools were examined biweekly in these children until 6 months of age and at least four times per year thereafter until 2 years of age and after each diarrheal episode. Blood samples were obtained at birth and at 3, 6, 9, 12, 18, and 24 months of age. Antibodies against glycine-extracted membrane antigens, purified flagella, and cholera toxin (CT) were assayed by an enzyme-linked immunosorbent assay. The results showed that titers of antibody against the three tested antigens increased in children between 6 and 12 months of age and that nearly all children were immunized by the age of 2 years. A significant fall in anti-flagellum (P less than 0.001) and anti-glycine extract antibodies (P less than 0.001) occurred between birth and age 3 months, and children who had Campylobacter infections during the first 6 months of life had significantly (P less than 0.02) less anti-flagellum antibodies at birth than did those who did not have Campylobacter infections during that time. Three-month-interval stratification showed that CT antibody titers at birth were significantly lower in children who developed Campylobacter infection than in controls (P = 0.05). Comparison of the immune response to a single Campylobacter episode showed that 46.6% of children with asymptomatic carriage did not respond to CT while only 5% of children with diarrhea-producing infection did not respond to CT (P less than 0.01), compared with 30% (P = 0.065) and 56% (P less than 0.01), respectively, of the age-matched controls. Antibodies to flagella seem to protect against enteric colonization by Campylobacter jejuni and Campylobacter coli.

Virulence of Campylobacter jejuni for chicken embryos

The pathogenicity of Campylobacter jejuni was examined in chicken embryos. In this system, mortality data and histopathological findings induced by organisms and by bacterium-free filtered broth were identical. The absence in chicken embryo tissues both of organisms and of an inflammatory infiltrate suggests a toxin etiology.

Enterotoxin production and serogroups of Campylobacter jejuni and Campylobacter coli from patients with diarrhea and from healthy laying hens

Enterotoxin production, a possible virulence factor, was determined in Campylobacter jejuni and Campylobacter coli by two different techniques, the CHO cell test and the GM1 enzyme-linked immunosorbent assay. The frequency of enterotoxigenic Campylobacter strains was 32% in strains from both humans with acute enteritis and healthy laying hens, as measured by the CHO cell test. The CHO cell test was significantly more sensitive than the GM1 enzyme-linked immunosorbent assay in the detection of enterotoxigenic strains. Enterotoxin production was compared with the presence of heat-stable and heat-labile antigens. There was no significant correlation between enterotoxin production and serogroups for C. jejuni or C. coli. The difference in enterotoxigenicity between C. jejuni (34.1%) and C. coli (21.9%) was not significant.

Direct isolation of atypical thermophilic Campylobacter species from human feces on selective agar medium

Campylobacter upsaliensis is the name which has been proposed for a new group of thermophilic campylobacter strains which differ from C. jejuni and C. coli in having a negative or weak catalase reaction. Primary isolation of these strains from human feces has been achieved only by use of filtration techniques. We report here direct isolation of strains corresponding to C. upsaliensis from stools of six children. The strains were isolated on a newly described campylobacter-selective medium. The strains were oxidase positive, hippurate negative, nitrate positive, negative for H2S in triple sugar iron, and susceptible to cephalothin (30-micrograms disk) and nalidixic acid (30-micrograms disk), and they grew at 37 and 43 degrees C, but not at 25 degrees C. The selective medium used was a blood-free, charcoal-based medium consisting of Columbia agar base, activated charcoal, cefoperazone (32 micrograms/ml), vancomycin (20 micrograms/ml), and cycloheximide (100 micrograms/ml). The medium supported the growth of the weakly reacting or catalase-negative strains, with colony counts equivalent to those obtained on antibiotic-free horse blood agar. These strains could not be isolated directly from stool on Skirrow medium, and colony counts confirmed that this medium could not support a low inoculum of these organisms. The clinical significance of these strains is unknown. We conclude that C. upsaliensis can be isolated directly from stool by using a selective medium, without the need for filtration.

Recovery of Campylobacter from human faeces stored at 4 degrees C

Six hundred and thirteen fresh diarrhoeal faeces were inoculated on Skirrow blood agar (SK), on Preston blood free agar (PBF), and in Campy-thioglycolate broth (CT). After 24 h of storage at 4 degrees C, specimens were again inoculated on SK and PBF, and in Campylobacter enrichment broth (CEB). CT tubes were placed overnight at 4 degrees C. Plates and CEB tubes were incubated at 43 degrees C in microaerophilic conditions. A total of 68 specimens was positive for campylobacter on direct plating. Sixty-four of them were also recovered after subculturing from CT, and only 51 from CEB. Delayed inoculation of plates after storage of samples at 4 degrees C yielded 57 isolates. The storage of faeces at 4 degrees C for 24 h significantly reduces the number of campylobacter isolates. When samples are not plated immediately we recommend inoculating a CT tube maintained at 4 degrees C overnight as a holding medium.

Early treatment of Campylobacter jejuni enteritis

The bacteriologic and clinical effects of early antibiotic treatment of Campylobacter jejuni enteritis were studied. Erythromycin rapidly eliminated C. jejuni from stools, whereas trimethoprim-sulfamethoxazole did not. Despite its bacteriologic effectiveness, erythromycin did not reduce the duration or severity of diarrhea, abdominal pain, or other symptoms.

Human disease associated with "Campylobacter upsaliensis" (catalase-negative or weakly positive Campylobacter species) in the United States

Catalase-negative or weakly positive (CNW) thermotolerant campylobacteria, first isolated from dogs in 1983, were recently recognized as a new species, "Campylobacter upsaliensis," but their association with human illness has not been established. Twelve human isolates received at the Centers for Disease Control between 1980 and 1986 were identified as CNW campylobacteria by biochemical tests, cellular fatty acid composition, and antimicrobial susceptibility patterns. Eleven CNW Campylobacter strains tested by DNA-DNA hybridization (hydroxyapatite method) were all highly related and were related to two "C. upsaliensis" strains at the species level (86% under optimal conditions and 76% under stringent conditions). Clinical information was obtained for 11 human isolates from three stool and eight blood specimens. They were isolated from four female and seven male patients 6.5 months to 83 years of age residing in 10 different states. The patients had a wide spectrum of illnesses. The stool isolates were obtained from two previously healthy persons during episodes of acute gastroenteritis and from one immunocompromised patient with persistent diarrhea and fever. The blood isolates were obtained from two infants with fever and respiratory symptoms; a young woman with a ruptured ectopic pregnancy; three elderly men with underlying chronic diseases; and two immunocompromised adults. In a bactericidal assay to assess sensitivity to serum, seven of eight blood isolates showed some resistance to killing by pooled normal human serum. These observations suggest that "C. upsaliensis" is a potential human pathogen associated with both gastroenteritis and bacteremia in normal hosts and with opportunistic infection in immunocompromised individuals.

Therapy for shigellosis. I. Randomized, double-blind trial of nalidixic acid in childhood shigellosis

We compared nalidixic acid, 55 mg/kg/day, with ampicillin, 100 mg/kg/day, both given orally for 5 days, in the treatment of children with dysentery caused by shigellosis. All patients entered into the study had illness of less than 72 hours' duration and no prior allopathic drug therapy. Treatment was randomized and administered in double-blind fashion. Patients initially treated with ampicillin who were infected with a Shigella strain resistant to ampicillin were considered as a separate group (ampicillin-R). All isolates were susceptible to nalidixic acid. Similar percentages of patients treated with nalidixic acid (26/32, 81%) and with ampicillin (17/22, 77%) were clinically cured by the end of therapy; the rate in ampicillin-R (3/14, 21%) patients was significantly lower (p less than 0.001). Stool frequency in patients treated with nalidixic acid was significantly less than for ampicillin-treated or ampicillin-R patients during the final 3 study days. All patients treated with nalidixic acid and ampicillin had Shigella eradicated from their stool by day 3, compared with 77% (10/13) of ampicillin-R patients (p less than 0.05, ampicillin-R vs nalidixic acid or ampicillin). We conclude that nalidixic acid is an effective alternative to ampicillin in the treatment of shigellosis caused by nalidixic acid-susceptible strains.

Colonization of gastrointestinal tracts of chicks by Campylobacter jejuni

Bacterial enumeration and histologic examination of organs and tissues of 8-day-old chicks 7 days after peroral inoculation with Campylobacter jejuni revealed that the organism colonized primarily the lower gastrointestinal tract. The principal sites of localization were the ceca, large intestine, and cloaca, where densely packed cells of C. jejuni were observed in mucus within crypts. Examination of C. jejuni-colonized crypts by transmission electron microscopy revealed that the campylobacters freely pervaded the lumina of crypts without attachment to crypt microvilli. Understanding the mechanism of colonization may lead to approaches that will reduce the incidence of C. jejuni carriage by poultry.

Contemporary issues: diseases with a food vector

Foodborne disease has become a contemporary issue. Several large, well-publicized outbreaks of foodborne disease have heightened public awareness that harmful microorganisms may be present in food and that chronic as well as acute disease may be caused by foodborne microbes. The field of food microbiology has likewise experienced a resurgence of interest. New tools, such as recombinant deoxyribonucleic acid technology and monoclonal antibody production, used to elucidate microbial virulence factors have facilitated identification of disease-causing microbes once thought to be harmless and demonstrated the complexity of individual virulence mechanisms previously considered to be well understood. Foodborne pathogens are also causing disease via some surprising food vectors, such as chopped, bottled garlic and sauteed onions. In addition to acute gastrointestinal disturbances, certain microorganisms may, through complex interactions with the human immune response, cause chronic diseases that affect several major organ systems. These microbes are serving as models in studies of molecular mimicry and genetic interrelatedness of procaryotes and eucaryotes. Other recently recognized attributes of foodborne microorganisms, such as the heat shock phenomenon and the possible nonculturability of some bacteria, may affect their ability to cause disease in humans. Because foodborne disease is a major cause of morbidity and mortality, the study of these diseases and their causative microorganisms presents a unique challenge to many professionals in the subdisciplines of microbiology, epidemiology, and clinical medicine.

Diagnosis and management of dysentery by community health workers

To develop guidelines for community health workers in the treatment of patients with diarrhoea, diarrhoea prevalence was actively surveyed for a year in a remote rural community of 915,000 persons, and the enteric pathogens and clinical features associated with diarrhoeal illness were determined in a sample of 300 patients. Bloody diarrhoea accounted for 39% of all diarrhoea episodes and 62% of diarrhoea-associated deaths. 51 (50%) of 101 patients with a history of bloody diarrhoea had Shigella infection, compared with 31 (16%) of 199 patients with other types of diarrhoea. A history of bloody diarrhoea was as predictive of the presence of shigella infection (positive predictive value 50%, negative predictive value 86%) as more complex prediction schemes incorporating other clinical features or stool microscopic examination. In the area of Bangladesh where the study was done reduction of diarrhoea-related morbidity and mortality will depend on control and treatment of shigellosis, and community health workers have been instructed to provide antibiotics for patients with a history of bloody dysentery.