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Biomedical subjects

R Möllby

Publications and source records attributed to R Möllby.

At least 73 records · Page 4Linked to original sources
PubMed1991

Evaluation of serology and nasopharyngeal cultures for diagnosis of pertussis in a vaccine efficacy trial.

Nasopharyngeal cultures and titer rises in paired sera were evaluated in a placebo-controlled pertussis vaccine efficacy trial. IgG ELISA for filamentous hemagglutinin (FHA) identified 30 (88%) of 34 placebo recipients and 33 (89%) of 37 vaccine recipients with culture-verified Bordetella pertussis infections, whereas IgG ELISA for pertussis toxin (PT) showed higher diagnostic sensitivity in the placebo group than in the vaccine groups. The CHO cell assay did not improve sensitivity. Children with Bordetella parapertussis infections had rises of titers of antibody to FHA of the same magnitude as children with B. pertussis infections. Sensitive serologic criteria, based on the intraassay variations, identified 105 additional culture-negative cases with significant titer rises in paired sera. IgG ELISA for FHA and PT and IgA ELISA for FHA were reliable assays, and bacterial isolation rates were lower in vaccine recipients than in placebo recipients with serologically defined pertussis.

Antibodies, Bacterial↗
PubMed1991

Diagnosis of pneumonia by cultures, bacterial and viral antigen detection tests, and serology with special reference to antibodies against pneumococcal antigens.

In a prospective study of the etiology of pneumonia 196 adult patients were included. One of the following criteria was required for diagnosis of pneumococcal pneumonia: isolation of pneumococci from blood; isolation from transtracheal aspirate; isolation from sputum or nasopharynx or detection of capsular antigen in sputum in combination with a significant increase in antibodies against at least one pneumococcal antigen (type-specific capsular polysaccharide, C-polysaccharide, pneumolysin); or increase in antibodies against two pneumococcal antigens. Pneumococcal pneumonia was diagnosed in 63 patients (32%). Other diagnoses were nonencapsulated Haemophilus influenzae isolated from transtracheal aspirates, 9; Mycoplasma pneumoniae diagnosed by serology, 17; Chlamydia psittaci, 6; and viral infections, 42. Twenty-two patients (11%) had evidence of infection with more than one agent. The pathogen could not be determined in 70 (36%). Many patients were given antibiotics before admittance to the study, and in some cases a convalescent serum sample was not available.

Adolescent↗
PubMed1991

Biochemical phenotypes of enteropathogenic Escherichia coli common to Iran and Sweden.

A collection of 143 strains of enteropathogenic Escherichia coli (EPEC) of 11 different serogroups isolated from children with diarrhoea, 71 in Sweden and 72 in Iran, was tested for similarity with a computerised biochemical fingerprinting method. From Sweden, there were 54 different phenotypes, 42 consisting of a single strain and 12 (common phenotypes) containing more than one isolate. From Iran, there were 48 different phenotypes, 38 with only one strain and 10 with more than one. Many of the strains which were biochemically similar, in both countries, also had similar virulence factors. Nine Swedish and 20 Iranian isolates showed biochemical identity to at least one of the strains of the other country, most of them belonging to serogroups O55, O119, O126, O127 and O128. The value of the biochemical fingerprinting method as an epidemiological tool and its ability to evaluate clonal relations among E. coli strains in different geographical areas is discussed.

Adhesins, Escherichia coli↗
PubMed1991

Biochemical fingerprinting of water coliform bacteria, a new method for measuring phenotypic diversity and for comparing different bacterial populations.

A simple, automated microplate system for biochemical characterization of water isolates can be used to obtain fingerprints of the bacterial flora from various water samples. Mathematical models for calculating the diversities and similarities between bacterial populations are described for such fingerprints. The diversity may give information on whether an indigenous or allochthonous flora is present, and the similarities between bacterial populations, as calculated by using a population similarity coefficient (Sp), may indicate contaminations between different water samples. The system was demonstrated on coliform bacterial populations from various water samples, with or without suspected intercontamination. For unrelated water samples, the Sps were close to 0, whereas repeated samples of the same source showed Sps of 0.64 to 0.74. The Sp values from several water samples were also clustered to form a dendrogram, thus indicating the relative similarities between the bacterial populations to confirm suspected common sources of pollution.

Bacterial Typing Techniques↗
PubMed1991

Clinical and histologic features differentiating non-relapsing colitis from first attacks of inflammatory bowel disease.

This is a study of first attacks of colitis, evaluating prospectively the overall course with repeated histologic, clinical, laboratory, and initial microbiologic examinations. Forty-two attacks of colitis could after a follow-up period of 5.5 years be separated into relapsing and non-relapsing types. Relapse was chosen as a prerequisite for a final diagnosis of inflammatory bowel disease. In the non-relapsing group 72% of the patients harboured enteropathogenic bacteria. An insidious onset of diarrhoeal symptoms was highly discriminant of inflammatory bowel disease, whereas an acute onset mostly occurred in patients with non-relapsing colitis. Macroscopic differentiation at sigmoidoscopy was not possible. Distorted crypt architecture (92%) and/or basal plasmacytosis (77%) at initial biopsies strongly indicated inflammatory bowel disease but was also found transiently in patients with infectious colitis (19%). Thus, careful microbiologic and clinical investigation and repeated histologic examinations are necessary to distinguish infectious colitis from inflammatory bowel disease.

Adult↗
PubMed1990

Secondary analyses of the efficacy of two acellular pertussis vaccines evaluated in a Swedish phase III trial.

A placebo-controlled efficacy trial of two acellular pertussis vaccines carried out in Sweden in 1986-87 used culture confirmation as the principal case definition. However, the sensitivity of pertussis culture is low, and secondary analyses using more sensitive serological diagnostic criteria have therefore been carried out. These analyses confirm that vaccination with pertussis toxoid alone does protect against typical whooping cough with laboratory confirmation, but show that it does not protect against infection or colonization. There is evidence that the addition of filamentous haemagglutinin provides some protection against infection. Bacterial isolation rates were lower in vaccinated than unvaccinated children with serologically confirmed pertussis and increased with disease severity.

Child↗
PubMed1990

Evaluation of numerical typing systems for Escherichia coli using the API 50 CH and the PhP-EC systems as models.

Reproducible and discriminating typing methods are required for epidemiological investigations. Numerical typing systems analyse patterns obtained in various ways by calculating similarity coefficients between isolates. In the present study, various measures of the efficiency of a numerical typing system are quantified. These include reproducibility, accuracy, and discrimination power. Three different numerical typing methods for Escherichia coli were compared using these measures: (a) Biotyping with API 50 CH system, (b) Biochemical fingerprinting with the API 50 CH system and (c) Biochemical fingerprinting with the PhP-EC system. Biotyping qualitatively measures the results of a set of biochemical reactions as + or -. Biochemical fingerprinting also uses biochemical reactions, but the tests are scored quantitatively by measuring the kinetics and intensity of each reaction. It was found that biotyping yielded poor reproducibility. When biochemical fingerprinting analysis was used with the API 50 CHE system the reproducibility and the discrimination was good. The PhP-EC system for biochemical fingerprinting showed equal reproducibility but was superior to the API 50 CH system with regard to discrimination power.

Bacterial Typing Techniques↗
PubMed1990

Evaluation of the stability of biochemical phenotypes of Escherichia coli upon subculturing and storage.

Stability of the biotypic characters of 72 enteropathogenic Escherichia coli (EPEC) and 21 faecal E. coli strains was evaluated after storage and after subculturing using a computerized biochemical fingerprinting method. Sixteen (22%) EPEC strains and nine (43%) faecal strains exhibited changes in their biochemical reactions after subculturing. In contrast, strains stored at -70 degrees C and 4 degrees C did not show any measurable changes. Of 23 biochemical markers tested, eight were subject to changes in at least one of these strains. Changes in lactulose fermentation was most frequent, occurring in 17 (18%) strains. A decrease or loss of activity in the fermentation of 5-ketogluconate, arbutin and methyl beta-D-glucoside in six strains (6%), and an increase in the ability to ferment sucrose, raffinose, melibiose and D-arabinose in 20 strains (22%) were observed. Mean similarity of the strains, when compared pairwise before and after subculturing, was slightly affected by these changes, but the overall biochemical phenotypes of the strains remained constant.

Biomarkers↗
PubMed1990

In vitro activity of norfloxacin and other antibacterial agents against gastro-intestinal pathogens isolated in Sweden.

The in vitro activity of norfloxacin was compared to that of ampicillin, doxycycline, chloramphenicol, trimethoprim in combination with sulfamethoxazole (1/20), and erythromycin, against 272 clinical isolates of gastro-intestinal pathogens. Norfloxacin was the most active compound of those tested with MICs in the range 0.004-2 mg/l. Concentrations inhibiting 90% of the strains (MIC 90) were 0.008 mg/l for Vibrio cholerae, 0.016 mg/l for Aeromonas hydrophila, 0.032 mg/l for Vibrio cholerae non 01, 0.064 mg/l for Vibrio parahaemolyticus, Yersinia enterocolitica 03, enterotoxigenic (ETEC) and enteropathogenic (EPEC) Escherichia coli and Shigella species, 0.125 mg/l for Salmonella species, and 0.5 mg/l for Campylobacter species. Resistance to one or several of the other drugs was seen with higher or lower frequency in all the bacterial species tested. No cross-resistance between any of the other agents and norfloxacin was recorded.

Bacteria↗
PubMed1989

Amoxicillin promotes vaginal colonization with adhering Escherichia coli present in faeces.

This study is aimed at a better understanding of the pathogenesis of urinary tract infection (UTI) by examining factors influencing the bacterial ecology of the genital tract. It comprises two sets of experiments in a monkey model. In the first the persistence and transmission between individuals of a P-fimbriated Escherichia coli (strain DS17) in faeces was examined and in the second we studied the influence of amoxicillin on the occurrence of this strain in the vagina. Orally administered E. coli DS17 was shown to spread to cage mates and to persist in the gut for at least 17-18 months. One of four monkeys so colonized developed three separate UTIs with the DS17 strain. The second set of experiments comprised four other monkeys, who either harboured the E. coli DS17 strain in the faeces and/or in small amounts in the vagina, probably through contamination during defaecation. Amoxicillin induced a persistent vaginal E. coli DS17 colonization in nine of ten experiments. The study thus shows that uropathogenic E. coli may persist for long time in the faeces and that, in this situation, amoxicillin may promote an abnormal, vaginal E. coli colonization similar to that characteristic of females prone to recurrent UTI and often preceding manifest urinary infections.

Amoxicillin↗
PubMed1989

Intestinal colonization with Clostridium difficile in infants up to 18 months of age.

The faecal colonization with Clostridium difficile was investigated among 343 infants during their first 18 months of life. Rectal swabs were taken at the ages of 6 days, 6 weeks, 6 months, 11 months and 18 months. About 25% of the children were colonized with Clostridium difficile between 6 days and 6 months of age. The colonization rate decreased to 3% at 18 months of age. The rate of strains producing cytotoxin was low in infants less than 6 months of age, but at that age about half of the strains isolated were toxin-producing. Breast-fed children were significantly less often colonized with Clostridium difficile than were bottle-fed infants, both at 6 weeks of age (21% versus 47%, p less than 0.05) and at 6 months of age (19% versus 39%, p less than 0.001). Colonization with Clostridium difficile at 6 months of age was associated with a greater frequency of diarrhoeal disease between 6 and 11 months of age (27% versus 16%, p less than 0.05). This association was even more pronounced when the bacteria persisted at 11 months of age (54%, p less than 0.01). Antibiotic therapy could not be demonstrated to influence colonization with Clostridium difficile at any age.

Age Factors↗
PubMed1989

Intestinal permeability assessed with polyethylene glycols in children with diarrhea due to rotavirus and common bacterial pathogens in a developing community.

Intestinal permeability was assessed with different-sized polyethylene glycols (PEG 400 and PEG 1,000) in small children with acute diarrhea. All children with acute diarrhea absorbed and excreted less PEG of all molecular sizes into the urine when compared with healthy control children (p less than 0.001). Children with acute rotavirus infection excreted significantly less PEG of all sizes than children with Shigella, Salmonella, and enteropathogenic Escherichia coli (EPEC) infection (p less than 0.001-0.01), suggesting a more severe mucosal lesion caused by rotavirus. In patients with severe malnutrition there was also a significant decrease in absorption of PEGs observed. In addition, malnourished patients with rotavirus diarrhea showed a pronounced decrease of PEGs in comparison with well-nourished patients. The ratio between the recovery of a large PEG molecule, 1,074 Da, and a small molecule, 370 Da, was utilized to assess the absorption of large molecules in relation to that of smaller ones. On applying this ratio, it was noted that the intestine in children with Shigella and EPEC infection was relatively more permeable to larger molecules than in healthy controls, while in rotavirus and Salmonella infection it was less permeable to larger molecules. In this study significant differences in the permeability characteristics were observed, suggesting etiology-specific effects on the mucosal barrier.

Child, Preschool↗
PubMed1989

Elimination of vaginal colonization with Escherichia coli by administration of indigenous flora.

A persistent vaginal colonization with a pyelonephritogenic strain of Escherichia coli, induced by administration of amoxicillin, was established in four adult cynomolgus monkeys. This colonization mimicked the one seen in urinary tract infection-prone human females. Attempts to eliminate the E. coli colonization and restore normal conditions were made. Either suspensions of lactobacilli or vaginal fluid from a healthy unmanipulated monkey was administered as repeated vaginal flushes for 5 to 9 days. A total elimination of vaginal E. coli was observed in two of six experiments with lactobacilli, and a decrease was observed in the other four. A better result was obtained with flushes of vaginal fluid, which eliminated the E. coli colonization in eight of eight experiments. In two of these, a single flush was sufficient to obtain a decolonization. The ability of fresh vaginal fluid to eliminate E. coli from the vagina could be transferred from one monkey to another. This study demonstrates the role of the normal flora in the defense against genital colonization with potentially pathogenic adhering E. coli. The possible clinical relevance of these findings must be further examined.

Amoxicillin↗
PubMed1988

Faecal colonization with P-fimbriated Escherichia coli between 0 and 18 months of age.

A prospective study of faecal colonization with P-fimbriated Escherichia coli between 0 and 18 months of age was conducted in 751 healthy infants. The influence of breast-feeding and treatment with antibiotics on this colonization was studied. Colonization with P-fimbriated E. coli increased with age from 10% at 6 days to 30% at 18 months of age (P less than 0.01). Breast-feeding influenced colonization at 6 weeks of age when breast-fed children harboured fewer bacterial species (P less than 0.001) and fewer P-fimbriated E. coli (P = 0.06) than bottle-fed infants. Treatment with antibiotics increased the colonization rate with P-fimbriated E. coli at the age of 11 months (P less than 0.05). However, this was not true for treatment with ampicillin, which increased colonization rate with Gram-negative species other than E. coli (P less than 0.05). Fifty per cent (378) of all children were colonized and a quarter (183) had pure cultures of P-fimbriated E. coli in at least one faecal sample. The clinical importance of this colonization remains to be shown.

Aging↗
PubMed1988

Serum antibodies to pneumolysin in patients with pneumonia.

Serum antibodies to purified pneumolysin were determined by enzyme-linked immunosorbent assay (ELISA) in paired samples from 406 adult patients with community-acquired pneumonia and in samples from 184 healthy controls. A high sensitivity (83%) was obtained in patients with blood culture-confirmed pneumococcal pneumonia. In patients with a tentative pneumococcal diagnosis based on culture of samples from the sputum or the nasopharynx, 45% were positive by ELISA. The difference likely reflected the different relevance of cultural findings for the diagnosis of pneumococcal pneumonia. A significant rise in ELISA titer was found in 17% of the patients. When the diagnosis was also based on high titers, 25% were positive. Pneumococcal pneumonia diagnosed by the pneumolysin ELISA was significantly more common in the patients with a more severe disease and who required hospitalization (21 versus 5% for outpatients). Younger patients were more often positive for pneumococci as determined by high titers, while older patients showed titer rises. Mixed infections with other infectious agents were not uncommon. The finding of low titers in acute-phase samples from positive patients and in the youngest and oldest age groups of healthy controls were unexpected, indicating that further studies on the role of pneumolysin in pneumococcal disease are warranted.

Adolescent↗
PubMed1988

Virulence factors in Escherichia coli strains isolated from Swedish piglets with diarrhea.

Parenteral vaccination of sows against Escherichia coli diarrhea in their newborn piglets has become more common during the last decade in Sweden, and the vaccination has generally had positive effects. For more than 20 years we have investigated E. coli strains isolated from piglets and weaned pigs with enteric disorders, noting the presence of O groups, enterotoxins, and adhesins. There has been a continuous change in the frequency of these virulence factors. The present study was performed during 1983 and 1984 to follow this change, since such information is essential for the proper choice of vaccines. A total of 856 E. coli strains were obtained from 683 herds divided into three age groups: 1 to 6 days old, 1 to 6 weeks old, and weaned pigs. O group 149 still dominated in the last two age groups, while O group 101 was, for the first time, the most frequent O group in neonatal piglets. All but four O149 strains carried the K88 antigen, which was found in only one other strain (O group 8). K99 antigen was most often found in O groups 101 and 64, and among all the K99 strains ST mouse was the most common (44 of 57), followed by ST mouse-ST pig strains (12 of 57). The 987P antigen was demonstrated in 26 strains belonging to O groups 141 and OX46 and nontypable strains. Two strains belonging to O group 101 were positive for F41 antigen; one of them also carried the K99 antigen. Among all non-O149 strains, ST mouse was the most common type of enterotoxigenic E. coli ( n = 88), followed in decreasing order by ST mouse-ST pig strains ( n = 69) and ST pig strains ( n = 33). In 114 strains producing enterotoxins no adhesive factor was found. Thus, vaccination of the Swedish sow population for more than 5 years with vaccines containing O149 and K88 antigens has apparently changed the pattern of enterotoxigenic E. coli in neonatal diarrhea. The frequency of O149:K88 strains has been reduced, and O101:K99:ST mouse strains now dominate. However, O149 strains remain the dominant O group in piglets older than 1 week. In spite of all our diagnostic efforts, no virulence factors were detected in about one third of the piglets and weaned pigs with enteric disorders.

Animals↗
PubMed1988

Acute diarrhoea in adults: aetiology, clinical appearance and therapeutic aspects.

A prospective study of acute diarrhoea was performed during 15 months 1981/1982 and included 731 patients and 240 controls. 43% had been infected abroad. A cluster of travellers with bacterial pathogens was diagnosed in July-August. The following pathogens were found: Campylobacter (18%), enterotoxigenic E. coli (6%), Salmonella spp. (5%), rotavirus (4%), Yersinia enterocolitica (3%), Giardia lamblia (3%), Shigella spp. (2%), Clostridium difficile (2%), enteroviruses (2%) and Entamoeba histolytica (less than 1%). More than 90% of the bacterial or parasitic enteropathogens were detected in the first stool sample. Only 10% of the patients needed hospital treatment and for 97% oral fluids were sufficient. The median duration of diarrhoea was 9 days. No fatal cases occurred and only 2 cases of chronic bowel disease were detected.

Acute Disease↗