Evaluation of Statens Serum Institut enteric medium for detection of enteric pathogens.

The efficacy of the Statens Serum Institut (SSI) enteric medium for isolation and direct identification of enteric pathogens was evaluated. Six different biochemical reactions can be read by using the SSI enteric medium, allowing direct identification of a range of enteric pathogens. All 248 gram-negative bacterial species that were tested grew on the SSI enteric medium. Only 10 of 248 bacteria (4%) showed discrepant results in the biochemical reactions, and none of these were enteric pathogens. Forty-three of 47 enteric pathogens (92%) produced identical rates of semiquantitative growth on the SSI enteric medium and 5% blood agar, whereas three Vibrio spp. and one Aeromonas spp. showed reduced growth. Gram-positive bacteria did not grow on the SSI enteric medium. Most enteric pathogens had a detection limit of 50 bacteria per ml of feces, but higher numbers of Vibrio spp. and some Shigella spp. were required for detection. The growth rates of 125 enteric pathogens and 12 Yersinia spp. on the SSI enteric medium, xylose lysine deoxycholate (XLD), Hektoen enteric (HE), Salmonella-Shigella (SS), and cefsulodin-irgasan-novobiocin (CIN) agar were compared. Detection rates after application of 200 CFU were 99% for SSI enteric medium, 92% for XLD, 88% for HE, and 82% for SS agar. The 12 Yersinia spp. grew excellently on both the SSI enteric medium and CIN agar. We conclude that the performance of the SSI enteric medium compares favorably to those of other media tested. Its ability to detect Yersinia spp. may limit the number of media needed in the typical laboratory. The direct identification of enteric pathogens on the medium may also provide a more rapid diagnosis.

Antibiotic resistance in Shigella and Salmonella in a region of Lithuania.

To gather information on the antibiotic susceptibility of Shigella and Salmonella in the Baltic countries, 98 Shigella and 100 Salmonella isolates collected consecutively in 1994 were examined. All Shigella isolates were resistant to at least two of 12 antibacterial agents: 100% were resistant to oxytetracycline, 92% to trimethoprim/sulfamethoxazole, 64% to chloramphenicol, and 64% to ampicillin. Five different resistance patterns were observed.

Salmonella typhimurium phage types from human salmonellosis in Denmark 1988-1993.

A total of 989 isolates of Salmonella enterica ssp. enterica serovar Typhimurium from cases of human salmonellosis were investigated by phage typing. The isolates comprised all isolates recovered during the month of August in each of the years from 1988 to 1993. Phage typing assigned 82.6% of the strains to 36 different definitive types, 11.9% of the strains belonged to types of unknown lysis pattern (RDNC), and 5.5% could not be typed by the phages used (NT). Three phage types (12, 66 and 110) made up approximately 50% of the isolates in each of the years investigated. During the period in question these types showed major changes in prevalence: phage type 12 increased from 4.0% in 1988 to a maximum of 55.2% in 1992, and phage type 66 and phage type 110 were reduced from 40.1% and 27.8% to a minimum of 3.9% and 4.8% in 1993 and 1992, respectively. The increasing prevalence of phage type 12 among isolates from human salmonellosis most likely reflects the increasing significance of pork as a source of human salmonellosis. The reduction in phage types 66 and 110 is paralleled by a reduction in S. Typhimurium in Danish poultry. Some phage types were associated with travel, namely 17, 193 and 194. It is concluded that phage typing, although here performed retrospectively, produces valuable epidemiological information regarding changes in the relative importance of different sources of infection in humans. It is suggested that phage typing be performed prospectively on both human and animal S. Typhimurium isolates in Denmark.

Comparison of four second generation kits for detection of IgG antibodies against Helicobacter pylori in adults.

Four serological kits for detection of IgG antibodies against H. pylori were tested on 132 adult patients with dyspeptic symptoms. Presence of H. pylori infection was established when either culture or microscopy of gastric biopsies were positive. The prevalence of H. pylori infection was 55% in the test population. With Anti-H. pylori MTP-assay (Roche), Pylori stat test kit (Whittaker), HM-CAP (Enteric Products Inc.) and Pyloriset EIA-G (Orion) the sensitivities were 97%, 95%, 81% and 68% respectively, the specificities were 53%, 56%, 71% and 69% respectively, the positive predictive values 72%, 74%, 79% and 74% respectively and the negative predictive values were 94%, 92%, 79% and 64% respectively.

Prevalence of antibodies against heat-stable antigens from Helicobacter pylori in patients with dyspeptic symptoms and normal persons.

Heat-stable antigens from Helicobacter pylori were investigated for the detection of serum IgG, IgA and IgM antibodies against H. pylori by an ELISA technique. Antibody titers against H. pylori were measured in 167 dyspeptic patients, of whom 96 were H. pylori positive confirmed by culture or microscopy, and in 482 controls (0-98 years). Increased IgG antibody titers were found significantly more often in dyspeptic patients with active chronic gastritis than in patients with normal morphology, as well as in H. pylori-positive patients as compared to H. pylori-negative patients, independent of the endoscopic findings. The heat-stable antigens were compared with acid glycine-extracted antigens and a high degree of concordance was found in the results obtained with the two antigen preparations. The differences in the IgA antibody titers against H. pylori between H. pylori-positive and H. pylori-negative dyspeptic patients were significant and may be useful to confirm a borderline IgG result. No differences were found in IgM antibody titer between H. pylori-positive and -negative patients. The greatest age-dependent increase in IgG and IgA antibody titers was found in children, and if a lower cut-off level is used for children than for adults, as has been proposed, the proportion of people with increased antibody titers against H. pylori would be almost constant from the age of between five and 10 years until the time between 61 and 80 years. Comparison of H. pylori IgG antibodies with IgG antibodies against Campylobacter jejuni and total antibodies against cytomegalovirus (CMV) showed a greater similarity between H. pylori and C. jejuni (R = 0.51) than between H. pylori and CMV (R = 0.22). This may possibly be caused by cross-reactions between H. pylori and C. jejuni. The H. pylori heat-stabile antigen seems not to be very different from other crude H. pylori antigens like acid glycine-extracted antigens, but purification and characterization of the antigens are needed to improve antibody assays.

IgG subclass antibodies against Helicobacter pylori heat-stable antigens in normal persons and in dyspeptic patients.

Measurement of serum IgG antibodies against Helicobacter pylori seems to be useful in the diagnosis of H. pylori infections. IgG subclass antibodies against H. pylori have, however, not been investigated thoroughly. In this study IgG1, IgG2, IgG3 and IgG4 antibody levels against H. pylori were measured using an ELISA technique in 187 normal adult persons and in 174 patients with dyspeptic symptoms, of whom 99 patients were H. pylori positive. None of the IgG subclass antibody levels were better than the total IgG level for the diagnosis of H. pylori infection. The discrimination between H. pylori-positive and H. pylori-negative patients was better with IgG1, IgG2 and IgG4 antibody levels than with IgG3 antibody level. IgG2 was the IgG subclass antibody that mainly contributed to the age-dependent increase in the IgG antibody level. This sustains the suspicion that cross-reactions between lipopolysaccharide (LPS) from H. pylori and LPS from other Gram-negative bacteria may occur.

Plasmid profiles as an epidemiological marker in Salmonella enterica serovar berta infections. Comparison of isolates obtained from humans and poultry.

Plasmid profiles of 674 Salmonella berta strains isolated in the period 1985-1989 from 674 cases of human infections were recorded. Five hundred and eighty-nine of the strains examined (87.4%) contained plasmids and the mean number of plasmids was 1.8 per strain. Sixteen different plasmid sizes were recognized, 13 of which had also been reported from S. berta of poultry origin. The plasmids formed 90 different profiles. Forty-five of these profiles, comprising 90.7% of isolates, had previously been recorded among poultry strains. Only 12 human isolates (1.8%) carried plasmids which were not demonstrated among isolates obtained from broilers. The prevalences of the 20 most commonly demonstrated profiles were not significantly different among isolates obtained from humans and broilers. The average difference between the prevalences of individual plasmid profiles was 2.1, with a standard deviation of 4.2. Based on the results, indications are that broilers represent the main reservoir for human S. berta infections in Denmark.

Non-typhoid Salmonella bacteraemia in Greater Copenhagen 1984 to 1988.

A retrospective survey of non-typhoid Salmonella bacteraemia in the period 1984 to 1988 was carried out by the five departments of clinical microbiology in Greater Copenhagen. A total of 168 patients were identified. A gradual increase was observed from 11 cases in 1984 to 58 cases in 1988. The corresponding incidence per 100,000 inhabitants in Copenhagen rose from 0.9 in 1984 to 5.0 in 1988. During the same period the total registered incidence of human Salmonella infections in Denmark increased from 17.6 to 67.4 per 100,000 inhabitants. The serotype most often isolated from bacteraemic patients was Salmonella dublin followed by Salmonella enteritidis and Salmonella typhimurium. Salmonella dublin demonstrated enhanced invasive and pathogenic properties. Predisposing factors were present in 56% of the patients; the most common was malignant disease. A fatal or complicated course of the bacteraemia was observed more frequently in patients with underlying diseases than in persons who had previously been healthy. A total of 17% of the patients died; one-fifth of these had a ruptured aortic aneurysm. It is concluded that the substantial increase in the number of cases and the often serious course taken by the infection demonstrate a need for increased efforts at prophylaxis.

Comparison of crossed immunoelectrophoresis, enzyme-linked immunosorbent assays, and tube agglutination for serodiagnosis of Yersinia enterocolitica serotype O:3 infection.

Antibodies against Yersinia enterocolitica serotype O:3 were measured by crossed immunoelectrophoresis (XIE) using whole-cell sonic extract as antigen and by enzyme-linked immunosorbent assays (ELISAs) using either purified lipopolysaccharide or whole formalinized cells expressing virulence plasmid-encoded surface antigens (pYV+ cells). The results were compared with those obtained with the standard tube agglutination method. Sera from three groups of people were examined by using these assays. The first group consisted of healthy blood donors, the second consisted of patients with recent infection due to microorganisms other than Y. enterocolitica O:3, and the third consisted of patients with recent Y. enterocolitica O:3 infection. Sera from the last group were also obtained at regular intervals for 12 months postinfection. Results obtained with XIE and the ELISAs were in good agreement with those obtained with tube agglutination. Variation, diagnostic sensitivity, and diagnostic specificity were satisfactory for all the assays studied. However, the lipopolysaccharide ELISA was less laborious than tube agglutination and XIE and carried a somewhat greater diagnostic specificity than the pYV+ ELISA. XIE and the pYV+ ELISA, on the other hand, also had advantages. XIE enabled simultaneous examination of the individual antibody response against a wide range of chromosome-encoded antigens, and the pYV+ ELISA enabled detection of specific pYV antibodies when sera were adsorbed with formalinized pYV-cured Y. enterocolitica O:3 cells prior to the assay.

[Bacteremia caused by zoonotic Salmonella types in greater Copenhagen in 1984-1988]. / Bakteriaemi forårsaget af zoonotiske Salmonella-typer i Storkøbenhavn 1984-1988.

The five departments of clinical microbiology in Greater Copenhagen have together carried out a retrospective review of bacteraemia caused by the zoonotic Salmonella serotypes in the period 1984-1988 in the municipalities of Copenhagen and Frederiksberg and in the County of Copenhagen. A gradual increase in frequency was observed from 11 cases in 1984 to 58 cases in 1988. The serotype most commonly isolated was Salmonella dublin followed by Salmonella enteritidis and Salmonella typhimurium. S. dublin was found to be more invasive and more virulent than the other serotypes. Predisposing factors were present in 56% of the patients; the commonest of these was malignant disease. Fatal or complicated course of the disease were observed more frequently in predisposed patients than in persons who had previously been healthy. A total of 17% of the patients died and one fourth of these had ruptured aortic aneurysm probably on account of Salmonella arteritis. 20% developed recurrence of bacteraemia while in the remaining patients the disease ran an uncomplicated course. It is concluded that the marked increase in the number of cases and the serious course taken by the infection demonstrate a definite need for increased prophylactic efforts in the food industry.

Bacterial contamination of stored water and stored food: a potential source of diarrhoeal disease in West Africa.

The food and water hygiene in two Liberian communities was studied in a house-to-house diarrhoea survey. The level of contamination with enterobacteria of drinking water stored in the households was significantly higher than at the water sources. Food hygiene standards were low, particularly in the urban slum where storage of cooked food for long periods led to bacterial multiplication at high levels. Infant foods were particularly heavily contaminated. It is concluded that when water supply programmes are planned, the presence of other risk factors for water-related diseases should be investigated. To ensure maximum health benefits, water projects should as a rule be accompanied by other interventions.

High prevalence of campylobacter excretors among Liberian children related to environmental conditions.

Campylobacter was the bacterial pathogen most prevalent in 859 children, aged 6-59 months, examined in a house-to-house diarrhoea survey in two Liberian communities. 44.9% of the children from an urban slum and 28.4% from a rural area were excretors. Since the prevalence of diarrhoea was very high and consequently many convalescent carriers were found, it was not possible to evaluate the pathogenic role of campylobacter. The excretor rate increased with age and was significantly correlated to the use of supplementary feeding, inversely correlated to the quality of the water supply, and also associated with helminthic infestation. Results from re-examination of 172 children suggested a high intensity of transmission. The findings all indicate the existence of a heavy environmental contamination with campylobacter, probably of both human and animal faecal origin.

Acute gastroenteritis in children attending day-care centres with special reference to rotavirus infections. I. Aetiology and epidemiologic aspects.

Acute gastroenteritis (GE) among 214 children (aged 6 months-7 years) attending day-care centres (DDCs) in the Copenhagen County was studied during a 12-month period. A total of 197 cases of GE was observed in 109 children (i.e. 51% of the participants). The aetiology was as follows: rotavirus (n = 48) (24%), pathogenic bacteria (n = 11) (6%), Giardia lamblia (n = 3) (2%), while the aetiology of 68% remains unknown. The pathogenic bacteria included Yersinia enterocolitica, thermophilic Campylobacter, Clostridium difficile (+/- toxin) and enteropathogenic E. coli. In 4% of the GE the infections were multiple and Cryptosporidium was seen in one of these cases. The rate of GE declined with age from 1.35 GE per child per year (age group 1.0- less than 2.0 years) to 0.36 (6.0- less than 8.0 years). Serum sampled at the start of the study period showed that the frequency of detectable rotavirus IgG increased with age from 48% in the 6 months- less than 1.0 year group to 96% in the 4.0- less than 7.0 year group. The highest rates of rotavirus GE occurred from January to April (i.e. the rotavirus season). Moreover, rotavirus GE was almost absent after the age of 4. Hence, the rates of rotavirus GE per rotavirus season per child were 0.80 (age group 6 months-less than 1.0 year), 0.32 (1.0-less than 2.0), 0.14 (2.0-less than 3.0), 0.16 (3.0-less than 4.0), 0.06 (4.0-less than 5.0) and 0.04 (5.0-less than 6.0). Only 2 out of the 48 rotavirus GE were reinfections.(ABSTRACT TRUNCATED AT 250 WORDS)

Screening for Campylobacter pyloridis in patients with upper dyspepsia and the relation to inflammation of the human gastric antrum.

Campylobacter pyloridis, a recently detected microorganism, was isolated from gastric antral mucosa in 58% of 119 consecutive patients with upper dyspepsia. There was a highly significant correlation between the presence of Campylobacter pyloridis and antral inflammation and a close relation to prepyloric and duodenal ulcer. There was no significant correlation with the severity or type of inflammation. This microorganism, which seems to be as common in Denmark as in other parts of the world, is considered a possible cause of gastroduodenal disease.

The antibiotic effect of the anti-depressive drug femoxetine and its stereo-isomeric analogs on diarrhoea producing enterobacteriaceae.

The present investigation has been undertaken to illustrate the antibacterial effect on 20 diarrhoea producing enterobacteriaceae of an anti-depressive drug available as femoxetine and its three analogs. It has been shown that the stereo-isomeric trans forms of femoxetine are more than twice as active as the cis forms and inhibited all the strains below 400 microgram/ml (1.2 mM). The two cis compounds only inhibited 11 and 9 of the 20 strains respectively in the investigated area 100 microgram/ml - 800 microgram/ml (0.3 mM - 2.4 mM). Our investigations point out that the bacterial cell has a target for psychopharmacologically active agents. Thus the known psychopharmaca and their stereo-isomeric analogs may represent a pool of potentially new antimicrobial drugs. Furthermore the bacterial model may be useful as a model system in the study of the interaction of neuropharmacological agents and other membrane active compounds with biological membranes.

The antibacterial effect of selected neuroleptics on Vibrio cholerae.

The present investigation has been undertaken to illustrate the anti-bacterial effect of chlorpromazine, clopenthixol and levomepromazine-maleate. It has been shown that clopenthixol has the strongest antibacterial effect. It is known that chlorpromazine also has an antisecretory activity. The fact that clopenthixol exists in cis(Z)- and trans(E)-isomerical compounds, and that these compounds both have an antibacterial effect, but only the cis-compound has an antisecretory and neuroleptic effect, might suggest the development of more specific pharmaceuticals in these new fields.

Changes during travel in the composition and antibiotic resistance pattern of the intestinal Enterobacteriaceae flora: results from a study of mecillinam prophylaxis against travellers' diarrhoea.

A randomized double-blind study was carried out in a group of Danish students visiting Mexico for 2 weeks to investigate the efficacy of mecillinam when given orally in preventing travellers' diarrhoea. The subjects took either 200 mg mecillinam daily as a single dose or placebo for 14 days. Nine (56%) out of 16 taking placebo and 3 (19%) out of 16 taking mecillinam developed travellers' diarrhoea (p less than 0.05). The pathogenic aetiology was not ascertained. A complete change in the Enterobacteriaceae flora took place during travel. A highly antibiotic-resistant Enterobacteriaceae flora was acquired in Mexico in subjects on mecillinam prophylaxis as well as on placebo. Selection of mecillinam-resistant bacteria was minimal.

Mecillinam, a new prophylactic for travellers' diarrhoea. A prospective double-blind study in tourists travelling to Egypt and the Far East.

The efficacy of mecillinam when given orally in preventing travellers' diarrhoea has been studied. Preliminary investigations in volunteers showed that single daily doses of up to 200 mg for 3 weeks were well tolerated. A randomised double-blind study was carried out in a group of tourists visiting Egypt and the Far East. The subjects took either mecillinam (200 mg daily) or placebo for 25 days. 19/36 tourists (53%) taking placebo and 5/38 tourists (13%) taking mecillinam developed travellers' diarrhoea during the treatment period (p less than 0.001). In the placebo group enterotoxigenic Escherichia coli (LT/ST) were found in 2 cases of diarrhoea and Salmonella in another 2 cases. In the remaining cases of diarrhoea the etiological agent was not found in either of the 2 groups.