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A Siitonen

Publications and source records attributed to A Siitonen.

At least 91 records · Page 5Linked to original sources
PubMed1994

Reactive arthritis following an outbreak of Salmonella infection in Finland.

The incidence and clinical features of reactive arthritis (ReA) following an outbreak of enteritis caused by Salmonella enterica ssp. enterica serovar 4,5,12:b:-were studied in the autumn of 1992. The outbreak occurred in several municipalities and originated from sprouted mung beans. A questionnaire on extra-enteric manifestations such as joint and eye symptoms was mailed 2 to 5 months after the outbreak to all bacteriologically proven cases. Two hundred and forty-six of the 272 (90%) subjects responded to the questionnaire; 224 (91%) reported having had enterocolitis, 22 (9%) were asymptomatic. Sixteen subjects fulfilled the criteria for ReA, and one had irities only. Thus, the incidence of ReA/iritis after S. enterica was 6.9%. Only four of the 155 (3%) subjects aged less than 16 yr developed ReA, as compared with 12 of the 91 (13%) older patients (P < 0.001). The only patient with iritis was also more than 16 yr old. The joint symptoms were oligoarticular in 10 (63%), monoarticular in five (31%) and polyarticular in one (6%). The most frequently affected joints were the wrists, knees and ankles. Joints of upper extremities only were affected in three (19%), of the lower extremities only in six (37%) and of both in seven (44%) subjects. In the majority of the patients ReA was mild. The joint symptoms persisted for less than 1 month in six, 2 to 6 months in five and more than 6 months in five. Thirteen subjects with ReA/iritis were tissue-typed for HLA; four (33%) had HLA-B27.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1994

Differentiation of Salmonella serovar infantis isolates from human and animal sources by fingerprinting IS200 and 16S rrn loci.

We genotyped Salmonella serovar infantis (referred to as S. infantis), which is the most widespread serovar among animals and the third most common cause of human salmonellosis in Finland. Molecular fingerprinting of the 16S rrn locus and the Salmonella-specific insertion sequence IS200 was used to type the 131 isolates originating from the main sources of S. infantis infection. The number of IS200 elements in S. infantis varied from zero to seven; three or more copies were present in 97% of the isolates, and 71% had four copies. There were four conserved chromosomal positions of IS200, which allowed us to group the isolates into three major clonal groups. We defined 11 unique IS200 profiles and five different ribotypes which, in combination, generated 15 genotypes highly restricted to the infection sources: 8 genotypes were typical of isolates from broiler chickens and cattle and seven genotypes were typical of isolates from humans. The eight genotypes of isolates from chickens represented two clonal groups which were differentially associated with chicken-producing companies. The typing scheme allows efficient discrimination between isolates from various infection sources and within sources and, therefore, provides a unique molecular tool for use in the study of the epidemiology of S. infantis infection.

Animals↗
PubMed1994

Hafnia alvei in stool specimens from patients with diarrhea and healthy controls.

We found an epidemiological association of Hafnia alvei with diarrhea, because the organism was isolated from 12 of 77 (16%) adult Finnish tourists to Morocco who developed diarrhea and from 0 of 321 tourists without diarrhea (P < 0.001). From another group of 112 adult Finnish diarrheal patients, only 2 (2%) yielded H. alvei. In contrast to some Bangladeshi strains of H. alvei, the Finnish strains were negative for the attachment-effacement lesion by an in vitro fluorescent acting staining test and also did not show homology to the Escherichia coli attachment-effacement gene (eaeA) by PCR. These results suggest that a mechanism or mechanisms other than the attachment-effacement lesion may also be involved in the association of H. alvei with diarrhea.

Actins↗
PubMed1994

Community-acquired pyelonephritis in adults: characteristics of E. coli isolates in bacteremic and non-bacteremic patients.

Escherichia coli strains isolated from the urine in 49 consecutive episodes of community-acquired pyelonephritis in adult women were characterized for adhesins and hemolysin production. The mean age of the patients was 56 years and 47% had at least 1 compromising condition. P fimbriae was found in 67% and hemolysin production in 35% of the strains; these figures were significantly (p < 0.001) higher than the corresponding figures (11% for each) among 287 strains isolated from stool of healthy adults (Siitonen A. J Infect Dis 1992; 166: 1058-1065). The prevalence of Non-P mannose-resistant adhesins and type 1C fimbriae was low (4 and 8%, respectively) and did not differ significantly from the corresponding prevalences (1 and 7%) in healthy adults. 74% fo the pyelonephritic (but only 22% of the stool) isolates had at least 1 of these 4 virulence factors (p < 0.001) and 37% and 7%, respectively, had at least 2 (p < 0.001). Nevertheless, the strains represented a wide variety of O:K serotypes without any indication of specially virulent clones. Of the 49 patients 15 had concomitant bacteremia, and in all except 2 compromised elderly patients the urinary and blood isolates were identical.

Adult↗
PubMed1993

Virulence-associated characteristics of Escherichia coli in urinary tract infection: a statistical analysis with special attention to type 1C fimbriation.

The relative virulence (defined as odds ratio) associated with different O and K antigens, adhesins and hemolysin production of Escherichia coli strains was assessed by separate and multivariate logistic regression analyses comparing 383 strains isolated from urine of adults with a urinary tract infection with 287 fecal strains from healthy adults; special interest was paid to evaluating the role of type 1C fimbriation. Type 1C fimbriae, found on 14% of UTI and 7% of fecal strains, were associated with O groups O2, O6, O18, and O75, with capsular type K5, with mannose-resistant (both P and non-P) adhesins, and with hemolysin production. In separate analyses, O8 (odds ratio 5.9) and O75 (9.2), capsular types other than K1 (1.9-2.1), P (2.9) and non-P mannose-resistant (17.4) adhesins, and hemolysin production (3.1) were each associated with high relative virulence compared to O1, Rough, and K1 phenotypes or lack of mannose-resistant adhesins or hemolysin. All these virulence effects were independent of type 1C fimbriation. In multivariate analysis, joint variation between factors decreased the apparent virulence-promoting effect of type 1C fimbriae, O6 antigen and hemolysin but increased that of other adhesins. Especially high relative virulence (odds ratio 404.2) was associated with the combination of O75:K5:non-P mannose-resistant adhesin identified on seven UTI but no fecal strains.

Adult↗
PubMed1993

Virulence characteristics of Escherichia coli in nosocomial urinary tract infection.

We examined 148 strains of Escherichia coli isolated from the urine from patients with nosocomial urinary tract infection (UTI). The prevalence of P fimbriation was only 11.5%. Of the strains, 17.6% expressed non-P M(R) adhesins (defined as strains expressing mannose-resistant but not P-specific hemagglutination); 33.1% produced hemolysin, and 15.2% expressed type 1C fimbriae. O6 was the most common group of O antigens (12.2%), closely followed by O75 (9.5%); both of these groups are relatively uncommon (4.5% and 1%, respectively) in fecal strains isolated from healthy adults. Of the strains with O6 and O75 antigens, 78.8% and 79% produced hemolysin, but of all other strains causing UTI, only 21% produced hemolysin. Of the strains with O6 antigens, 61% expressed non-P M(R) adhesins, but only 12% of all other strains causing UTI expressed non-P M(R) adhesins. There were no significant differences in the prevalence of virulence properties between strains isolated from patients with or without an underlying medical illness or between strains causing different clinical categories of UTI. We conclude that the prevalence of bacterial virulence factors is low among patients with nosocomial UTI.

Adult↗
PubMed1993

Short-term treatment of traveler's diarrhea with norfloxacin: a double-blind, placebo-controlled study during two seasons.

Clinical efficacy of norfloxacin for treatment of traveler's diarrhea in 106 Finnish tourists vacationing in Morocco was evaluated during two different seasons. When the criteria for diagnosis of traveler's diarrhea were fulfilled, norfloxacin (400 mg) or a placebo was given orally, twice daily for 3 days. All symptoms and signs subsided sooner in the norfloxacin group. The clearest difference was observed in the duration of diarrhea: 1.2 days in the norfloxacin group vs. 3.3 days in the placebo group (P < .001). The duration of diarrhea due to particular species was as follows for the two groups: in cases due to Salmonella enterica, 1.1 vs 4.1 days (P < .01); in cases due to Campylobacter jejuni, 1.8 vs. 5.0 days (P < .01); and in cases due to enterotoxigenic Escherichia coli, 1.0 day vs. 3.1 days (P < .01). The rate of full recovery during administration of norfloxacin or a placebo was also greater among the norfloxacin recipients: 84% vs. 47% (P < .001). No significant adverse effects were reported. Norfloxacin proved to be safe and effective in therapy for traveler's diarrhea.

Adolescent↗
PubMed1993

Invasive Escherichia coli infections in children: bacterial characteristics in different age groups and clinical entities.

Escherichia coli isolates from blood or cerebrospinal fluid of 135 children were characterized for serotype, adhesin and hemolysin production and compared with 94 fecal isolates from healthy children. Capsular type K1, sero-group O18 and rough-type lipopolysaccharide were predominant in neonatal infections (49, 16 and 16%, respectively) and also in meningitis and septicemia of infants from 7 days to 23 months of age (39, 17 and 13%). S-fimbriated strains were common in neonatal infections (23%) but rare (< or = 5%) in all other clinical groups. Pyelonephritis was the most common diagnosis in infants (49 of 72); it was associated with P-fimbriation (63%); serogroups O1, O2, O4, O6 or O7 (41%), and hemolysin production (37%). Invasive infections in older children (age > or = 2 years) were associated with predisposing factors and were caused by strains resembling fecal isolates; the only exception was hemolysin production which was detected in 40% of the disease but only 9% of the fecal isolates. Eight O:K:H serotypes were associated with invasive infections; they usually had K1 or K5 capsule and either P, S or type 1C fimbriae.

Adolescent↗
PubMed1993

Characteristics of Escherichia coli in acute community-acquired cystitis of adult women.

The characteristics of Escherichia coli isolated from the urine in 178 consecutive episodes of community-acquired cystitis in adult women were studied and compared with strains isolated from stools of 287 healthy adults. The prevalence of each of the previously described virulence-associated factors for urinary tract infection was significantly higher in the cystitis than in the stool isolates. The figures were 25.3% and 10.8%, respectively, for P fimbriation; 19.7% and 1% for Non-P MR adhesins, 13.5% and 7.3% for type 1C fimbriae and 22.5% and 10.8% for hemolysin production. 54% of the cystitis strains (but only 21.6% of the stool isolates) had at least 1 of these virulence-associated factors. These factors were mutually associated in a non-random manner; the association of P fimbriae with K1 and of Non-P MR adhesins and type 1C fimbriae with K5 capsules were highly significant. However, no clones specifically associated with cystitis could be identified. No significant differences were found between isolates from the first or recurrent UTI, or from younger or older, compromised or non-compromised patients. We conclude that P fimbriae, Non-P MR adhesins, type 1C fimbriae and hemolysin production all contribute to the establishment of cystitis in adults.

Acute Disease↗
PubMed1992

Seasonal variation in etiology of travelers' diarrhea. Finnish-Moroccan Study Group.

The etiology of travelers' diarrhea was studied in 579 adult Finnish tourists participating in two packaged tours to Morocco in the winter (n = 233) and fall (n = 346) of 1989. A research team accompanied the travelers, and a laboratory for enteric pathogens was established in Agadir. At least one pathogen was found in 62% of the 60 diarrhea cases in winter and in 58% of the 111 diarrhea cases in fall. Multiple pathogens were found less often in winter (8%) than in fall (21%, P less than .05). Campylobacter strains were the leading cause of travelers' diarrhea in winter, found alone or with other pathogens in 28% of the cases (but in only 7% in fall), whereas enterotoxigenic Escherichia coli (ETEC) was the most common pathogen in fall, present in 32% of the cases (8% in winter). Both differences are highly significant (P less than .001). Salmonella enterica was almost as common as ETEC in fall (25% of diarrhea cases) but rare in winter (10%, P less than .05). Thus, the etiology of travelers' diarrhea varied according to the season in the same tourist destination. This finding has relevance to both antimicrobial treatment and prophylaxis.

Adolescent↗
PubMed1992

Escherichia coli in fecal flora of healthy adults: serotypes, P and type 1C fimbriae, non-P mannose-resistant adhesins, and hemolytic activity.

Escherichia coli strains from feces of 287 healthy adults were analyzed for O:K serotypes, P and type 1C fimbriae, non-P mannose-resistant adhesins, and hemolysin production. O1, O2, O6, O7, O18, O25, and rough-type lipopolysaccharide accounted for 40% of all isolates. K antigen was present in 62%; K1 was identified in 30% and K5 in 10%. O1, O2, O18, rough lipopolysaccharide, and P fimbriation were significantly associated with K1 and O6, O25, and type 1C fimbriation with K5. The overall prevalence of virulence-associated determinants was 22%; 7% of the strains possessed two or three of them. These determinants were most often associated with 9 serotypes (O1:K1, O2:K1, O6:K1, O6:K5, O7:K1, O16:K1, O22:K-, O25:K5, and R:K1) among which their prevalence was 43%, three times greater than among the remaining strains (P < .001). No enteropathogenic or enterohemorrhagic E. coli-associated serotypes were detected.

Adhesins, Bacterial↗
PubMed1992

Fimbriation, capsulation, and iron-scavenging systems of Klebsiella strains associated with human urinary tract infection.

Thirty-two strains of Klebsiella pneumoniae and seven strains of Klebsiella oxytoca isolated from urinary tract infections in elderly adults were analyzed for capsular antigens, iron-scavenging systems, and fimbriation. All strains were capsulated. Twenty-seven different K antigens were identified among the strains, with no particular antigen dominating. All strains produced the iron-scavenging system enterochelin as analyzed by bioassay and DNA hybridization. In contrast, the aerobactin iron-sequestering system was not detected in any of the strains. All strains caused hemagglutination of tannin-treated human erythrocytes and reacted with an anti-type 3 fimbriae antiserum as well as in DNA hybridization with a type 3 fimbria-specific probe, indicating that the Klebsiella strains possessed this fimbrial type. Possession of type 1 fimbriae was analyzed by agglutination tests and by hybridization with DNA probes from two distinct Klebsiella type 1 fimbria gene clusters. Phenotypic expression of the type 1 fimbriae was found in 29 of 32 K. pneumoniae strains, whereas 30 strains reacted with either of the two type 1 fimbrial cluster DNA probes. In K. oxytoca, however, only three of seven strains expressed type 1 fimbriae and reacted with the DNA probes. The type 3 fimbriae were found to bind to a fraction of epithelial cells exfoliated in normal human urine, whereas the type 1 fimbriae bound strongly to urinary slime. No inhibitors of type 3 fimbrial binding were detected in human urine.

Aged↗
PubMed1992

Bacterial motility is a colonization factor in experimental urinary tract infection.

In an experimental urinary tract infection of the mouse, colonization of the urinary bladder by isogenic strains of Salmonella enterica serovar Typhimurium was found to depend on the motility of the bacteria. Strains were obtained by genetic recombination between a highly motile O-6,7 and a poorly motile O-4,5,12 strain. The O antigen did not interfere with the colonization, whereas motility did; flagellated and motile O-6,7 and O-4,5,12 bacteria colonized the bladder equally well.

Animals↗
PubMed1991

Prevention of travellers' diarrhoea by oral B-subunit/whole-cell cholera vaccine.

B-subunit/whole-cell cholera vaccine (BS-WC) has been shown to give Bangladeshi mothers and children only 3 months' protection against severe diarrhoea due to enterotoxigenic Escherichia coli (ETEC). Since a long-lasting effect is not necessary for protection against travellers' diarrhoea, a prospective double-blind study was conducted among tourists who went to Morocco from Finland. 307 tourists received two oral doses of BS-WC, whereas 308 controls received a placebo before departure. A research team went out with tourists and a laboratory for enteric pathogens was set up on location. A faecal specimen was taken from 100 randomly selected subjects before departure, from all travellers with diarrhoea, and routinely after return. Enteropathogenic bacteria were not isolated from any of the pre-departure specimens but were present during or after the holiday in 47% of tourists with travellers' diarrhoea, and in 14% of those without diarrhoea. BS-WC induced a 52% protection (p = 0.013) against diarrhoea caused by ETEC. The protection was better for mixed infections (65%, p = 0.016). The protective efficacy against a combination of ETEC and any other pathogen was 71% (p = 0.02), and that against ETEC plus Salmonella enterica even better at 82% (p = 0.01). Partial protection against travellers' diarrhoea is thus obtainable by active immunisation with BS-WC.

Administration, Oral↗
PubMed1990

Increase of trimethoprim resistance among Shigella species, 1975-1988: analysis of resistance mechanisms.

Trimethoprim (TMP) resistance among Shigella species isolated from Finnish travelers increased from 3.0% in 1975-1982 to 42.0%-43.8% in 1987-1988. Of the 317 TMP-resistant Shigella isolates identified during 1975-1988, 175 (55%) collected in 1985-1987 and in 1988 were tested further. Almost all (98%) were highly resistant to TMP, suggesting a plasmid-mediated origin. The type I dihydrofolate reductase (DHFR) gene was detected in 85% of the isolates studied. Twenty-three percent of the type I DHFR-positive isolates failed to hybridize with a probe detecting only Tn7-derived sequences, suggesting that the type I DHFR gene may occur independently of transposon Tn7. Four of the five Shigella species isolated from travelers to Sri Lanka hybridized with the probe for type V DHFR gene, implying a local distribution of the type V DHFR gene. The type II and type III DHFR genes were not found among the isolates studied. Only 12% of the TMP-resistant Shigella isolates failed to hybridize with any of the DHFR gene probes used.

DNA Probes↗
PubMed1990

Plesiomonas shigelloides bacteremia in a healthy girl with mild gastroenteritis.

A previously healthy 15-year-old girl fell ill with febrile gastroenteritis; Plesiomonas shigelloides was isolated from the blood 6 h after she had received one tablet of trimethoprim-sulfadiazine on the third day of symptoms. She recovered uneventfully. P. shigelloides may be isolated from the blood in immunocompetent patients with mild, uncomplicated gastroenteritis.

Adolescent↗