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Biomedical subjects

A Osterlund

Publications and source records attributed to A Osterlund.

At least 19 recordsLinked to original sources
PubMed2006

More than one variant of Listeria monocytogenes isolated from each of two human cases of invasive listeriosis.

Two variants of Listeria monocytogenes were isolated from blood cultures from each of two patients with listeriosis. Each variant displayed a two-band difference in DNA profile from the other by pulsed-field gel electrophoresis. Although this difference in profile is insufficient to distinguish clearly between the variants, the possibility of co-infection with different strains of L. monocytogenes needs to be considered. We suggest that more than one colony should be selected for molecular typing to aid interpretation during investigation of the sources and routes of Listeria infection.

DNA, Bacterial↗
PubMed2006

Staphylococcus aureus resistant to fusidic acid among Swedish children: a follow-up study.

We previously described the epidemic spread of a fusidic acid resistant clone of Staphylococcus aureus among children with bullous impetigo throughout Sweden 1. In this follow-up study we present data showing that Swedish clinicians in 2002 drastically reduced prescriptions of fusidic acid ointments, probably in response to the epidemic. Furthermore, we show that the fusidic acid resistant clone which dominated in 2001 is still the most prevalent fusidic acid resistant S. aureus in the population. The epidemic which reached its peak in 2002 is now clearly declining.

Adolescent↗
PubMed2005

Diversity among 2481 Escherichia coli from women with community-acquired lower urinary tract infections in 17 countries.

OBJECTIVES: In the recently published ECO.SENS survey, the antimicrobial susceptibility of Escherichia coli from urinary tract infections in women in 16 European countries and Canada was investigated. This study reports the diversity among these E. coli. METHODS: The 2481 E. coli, typed with the PhenePlate (PhP) System utilizing the dynamics and end result of 11 biochemical reactions in a microplate system, were clustered and the Simpson's index of diversity calculated. RESULTS: Seventy-four Common PhP Types (CT) comprising 2067 isolates and 414 Single Types (Si) were identified. Of these, 916 isolates (37%) belonged to one of the four most frequent CT (arbitrarily numbered CT48, 10, 26 and 20). CT48 with 400 isolates and 11 different susceptibility patterns, was widely disseminated across Europe and Canada and was the most frequent type in 13 countries and the second most frequent in the remaining four countries. Sixty-four per cent of the E. coli were susceptible to all eight investigated antimicrobials (CT48: 73%, CT10: 77%, CT26: 62% and CT20: 37%). Forty-six different susceptibility patterns were seen, the three most common being isolated resistance to ampicillin, resistance to ampicillin and trimethoprim, and isolated resistance to trimethoprim. Multiresistance, here defined as resistance to four or more of the investigated antibiotics, was distributed among E. coli belonging to several PhP types. CONCLUSIONS: There was no obvious correlation between the phenotypes identified with the PhP System and the susceptibility pattern. The data did not indicate clonal dissemination within or between countries as a major reason for differences in antimicrobial resistance rates.

Adult↗
PubMed2004

Antimicrobial resistance in Escherichia coli in urine samples from children and adults: a 12 year analysis.

AIM: To investigate the distribution and antimicrobial resistance in urinary tract pathogens, primarily Escherichia coli, in two age groups, children < or = 2 y and adults 18-50 y, over a period of 12 y. METHODS: From the database of the microbiological laboratory all urinary tract culture data were extracted and structured according to date, patient age, bacteriological findings, antimicrobial susceptibility results and sample type. Statistical longitudinal analysis of bacteriological findings and antimicrobial resistance trends in the two age groups were performed. RESULTS: Statistical significance was obtained for the following results. Escherichia coli was the most common pathogen in both age groups and irrespective of sample type. In E. coli resistance to ampicillin and trimethoprim was higher in children than in adults and increased over time in both age groups. Resistance to fluoroquinolones was higher in adults than in children and increased over time in both groups. Resistance to pivmecillinam, cefadroxil and nitrofurantoin was below 2% in 2001 in both age groups. CONCLUSION: The steadily increasing and now high E. coli resistance levels in children to ampicillin and trimethoprim render empirical therapy with these drugs doubtful. The stable and low levels of resistance to pivmecillinam, cefadroxil and nitrofurantoin (< 2% in 2001) make these drugs reasonable alternatives in uncomplicated lower urinary tract infections.

Adolescent↗
PubMed2002

Clonal spread among Swedish children of a Staphylococcus aureus strain resistant to fusidic acid.

An increased incidence of fusidic acid-resistant Staphylococcus aureus strains causing superficial infections among children in Sweden has been noted since the mid-1990s. Based on routine susceptibility testing data from 10 laboratories representing 8/21 Swedish counties during 1990-2001, the increase was first demonstrated in southern Sweden and subsequently became apparent throughout the country. Epidemiological typing using pulsed-field gel electrophoresis of recent isolates of fusidic acid-resistant S. aureus from 11 laboratories representing 8/21 Swedish counties revealed a high degree of similarity of band patterns, indicating a clonal relationship. Data from 1 of the laboratories demonstrated a close connection between this clone and impetigo. Sales statistics showed a pronounced increase in the use of fusidic acid ointments in the 0-12 y age group from 1998 onwards. There was, however, no statistically significant correlation between sales of fusidic acid ointments and resistance among S. aureus strains to fusidic acid.

Administration, Topical↗
PubMed2000

Outbreak of Salmonella typhimurium in cats and humans associated with infection in wild birds.

An outbreak of Salmonella typhimurium infection in cats and humans in Sweden in 1999, associated with wild birds, is described. In the county of Värmland, 62 sick cats were examined. All were anorectic and lethargic, 57 per cent had vomiting and 31 per cent had diarrhoea. It was considered likely that salmonellosis was transmitted from cats to humans, but there were only a few such cases.

Aged↗
PubMed1999

[Fluoroquinolone resistance of human pathogenic bacteria. Resistant E coli now appearing in Sweden].

Fluoroquinolone-resistance is a growing international problem. Warnings have earlier been issued concerning the risk of resistance development due to excessive fluoroquinolone prescription. The development of resistance among E. coli strains isolated from primary care patients with UTI is now apparent in Sweden. So far the majority of these strains manifest only low-level resistance. However, in view of the risk of high-level resistance developing among these strains further exposed to fluoroquinolones, it is important to think twice before prescribing these drugs.

Anti-Infective Agents↗
PubMed1999

The effects on resting ventilation of intravenous infusions of morphine or sameridine, a novel molecule with both local anesthetic and opioid properties.

UNLABELLED: Sameridine has both local anesthetic and partial mu-opioid receptor agonistic properties. The aim of this single-blinded, randomized, three-way cross-over study of 12 subjects was to investigate the effects on resting ventilation of two doses of sameridine: 0.15 mg/kg (S-Small) and 0.73 mg/kg (S-Large) compared with 0.10 mg/kg morphine. Each drug was infused IV over 20 min. Ventilation was measured by pneumotachography and in-line capnography, and sedation was rated by the subjects using a visual analog scale (VAS). Plasma was collected and analyzed for sameridine and morphine. At the end of drug infusion, minute ventilation (VE) and tidal volume (VT) were reduced in the S-Large group, and VE was reduced in the morphine group. End-tidal CO2 increased in both groups (P < 0.05), but respiratory rates remained unchanged. In the S-Small group, no ventilatory changes were recorded. In the S-Large group, the median sedation score was 6.8 cm with corresponding values in the morphine and S-Small groups of 3.3 and 2.5 cm, respectively. There was a relationship between the plasma concentration of sameridine and the depression of ventilation. We conclude that sameridine influences resting ventilation and that this effect is directly related to plasma concentrations of sameridine. From a ventilatory aspect, a clinical dose of sameridine with both local anesthetic and opioid properties seems safe. IMPLICATIONS: Sameridine, a molecule with both local anesthetic and analgesic properties, impaired resting ventilation after a large IV dose (0.73 mg/kg), more so than 0.10 mg/kg IV morphine. A clinical dose of sameridine (0.15 mg/kg) did not have any effects on ventilation.

Adult↗
PubMed1998

Biological strategies expressed by different Streptococcus pyogenes strains: an explanation of the epidemiology.

The numerous reports in the last ten years on the serious diseases caused by Streptococcus pyogenes indicate the continued significance of this pathogen. Furthermore, clinical studies and modern techniques have yielded new information on S. pyogenes and its pathogenic mechanisms. Although much still remains to be discovered about the biology of S. pyogenes, two different strategies--the 'epidemic' and the 'endemic' strategy--can be seen in the interaction of different S. pyogenes strains with the human host. The challenges posed by these two groups of bacteria are also outlined.

Disease Outbreaks↗
PubMed1997

Intracellular reservoir of Streptococcus pyogenes in vivo: a possible explanation for recurrent pharyngotonsillitis.

Numerous theories have been presented that attempt to explain the frequent recurrences of pharyngotonsillitis caused by Streptococcus pyogenes; these recurrences occur after seemingly adequate antibiotic treatment. We previously have demonstrated that Spyogenes can survive for up to 7 days intracellularly in immortalized human respiratory epithelial cells grown in an antibiotic supplemented medium. Viable S pyogenes were externalized and established an extracellular infection, whenever the extracellular antibiotic was removed. We have investigated the presence of intracellular S pyogenes in two in vivo studies using respiratory epithelial cells collected from patients with tonsillitis and the tonsils of asymptomatic carriers. Electron microscopy and immunohistochemistry demonstrated intracellular S pyogenes in pharyngeal epithelial cells in 13 of 14 patients with tonsillitis (93%). Furthermore, intracellular S pyogenes were found in macrophage-like cells in eight (73%) and in epithelial cells in four (36%) tonsils from 11 asymptomatic S pyogenes carriers. These in vivo data strongly support the hypothesis that intracellular S pyogenes can constitute a reservoir of bacteria with the potential to cause reinfections.

Adolescent↗
PubMed1997

An intracellular sanctuary for Streptococcus pyogenes in human tonsillar epithelium--studies of asymptomatic carriers and in vitro cultured biopsies.

A novel method for the in vitro culture of tissue biopsies is presented. Infected tonsillar biopsies were successfully cultured by means of the continuous flow of media without the addition of antibiotics. Histological and immunohistological examinations were carried out on sections of Streptococcus pyogenes-infected cultured tonsillar biopsies and sections from the surgically removed tonsils of asymptomatic S. pyogenes carriers. Low numbers of intracellular S. pyogenes were detected inside epithelial cells in eight out of 12 (67%) S. pyogenes-infected biopsies, and in four out of 11 (36%) tonsils of asymptomatic carriers. Our findings support the hypothesis that the sanctuary where S. pyogenes avoids antibacterial treatment is intracellular, which may provide a possible explanation of recurrent tonsillitis.

Adolescent↗
PubMed1996

Epidemiological observations on Streptococcus pyogenes serotype T1 in Uppsala county, Sweden 1989-1995.

During the period 1989-1995, the T-type distribution pattern of Streptococcus pyogenes pharyngeal isolates was compared with the annual incidence of culture-verified S. pyogenes bacteremias in Uppsala county, Sweden. An exceptional increase in the number of S. pyogenes bacteremias was seen in 1994. During the study period, the annual number of blood culture isolates was shown to correlate with the proportion of S. pyogenes serotype T1 among pharyngeal isolates.

Bacteremia↗
PubMed1995

Intracellular penetration and survival of Streptococcus pyogenes in respiratory epithelial cells in vitro.

Recurrence of pharyngotonsillitis caused by S. pyogenes after seemingly adequate antibiotic treatment has puzzled scientists for many years. We investigated the ability of S. pyogenes to invade HEp-2 cells and survive intracellularly. Five strains were tested, of which two were isolated from patients with recurrent pharyngotonsillitis, two without recurrent infection, while one was a reference strain. All five strains were found capable of penetrating the cells and surviving intracellularly for between 4 and 7 days. In this manner, an intracellular reservoir of bacteria was created, with the potential to cause recurrent infections.

Cells, Cultured↗