Biomedical subjects

M K Viljanen

Publications and source records attributed to M K Viljanen.

At least 19 recordsLinked to original sources

PubMed2004

Prospective evaluation of the GenoType assay for routine identification of mycobacteria.

In order to evaluate the proficiency of the GenoType Mycobacteria strip hybridization assay (Hain Lifescience, Nehren, Germany) for the routine identification of mycobacteria, the assay was used to identify 178 clinical isolates during a 6-month prospective study. The GenoType results were compared to the identification results obtained with AccuProbe (GenProbe, San Diego, CA, USA) or 16S rDNA sequencing, and an overall agreement of 89.3% between GenoType and the two reference methods was reached. The GenoType assay is, thus, a rapid and reliable method for the identification of clinically important mycobacteria, and it is well suited for use in a routine laboratory.

Bacterial Typing Techniques↗

PubMed2003

Performance of BACTEC 960 Mycobacteria growth indicator tube in the susceptibility testing of genetically characterized Mycobacterium tuberculosis isolates.

In this study, the 7H10 agar proportion method was compared with the BACTEC TB-460 and BACTEC MGIT 960 systems (BD Biosciences, USA) for the susceptibility testing of 22 genetically characterized Mycobacterium tuberculosis isolates for isoniazid, rifampin, streptomycin, and ethambutol. The 7H10 agar proportion method agreed with the resistant genotype in 87.3%, BACTEC TB-460 in 92.7%, and the MGIT in 96.4% of the cases, showing the high sensitivity of MGIT in the detection of resistant isolates.

Antitubercular Agents↗

PubMed2003

Interaction between Borrelia burgdorferi and immature human dendritic cells.

Antigen uptake and the following maturation of dendritic cells (DCs) are pivotal to the initiation of specific antimicrobial immune responses. DCs also play an important role in the recruitment and activation of the cells of the innate immune system. We have examined the interactions of DCs with Borrelia burgdorferi to find explanations for the difficulties the human immune system has in dealing with the bacterium. Phagocytosis of B. burgdorferi by immature DCs and the effect of the bacterium on the maturation and interleukin-8 (IL-8) secretion of DCs were studied. Borreliae were phagocytized and processed into fragments by DCs; narrow tube-like pseudopods and broad pseudopods were used for the engulfment. The immature DC population gained a heterogeneous appearance within 2 h of incubation with the borreliae. A 24 h coculture with borreliae induced maturation and IL-8 secretion in the DCs in a manner comparable with the effect of lipopolysaccharides. All strains studied, including a mutant strain lacking outer surface proteins A and B, were capable of inducing these responses. Thus, our results did not show any clear inadequacy concerning the way DCs are dealing with B. burgdorferi. However, further studies on the subject are required.

Borrelia burgdorferi↗

PubMed2003

Application of Bacillus anthracis PCR to simulated clinical samples.

We evaluated PCR for the detection of Bacillus anthracis DNA from simulated clinical specimens relevant for the microbiological diagnosis of anthrax or exposure to B. anthracis spores. In simulated blood specimens, the lowest limit of detection was 400 CFU per mL of blood, which may be sufficient for samples from patients with septic anthrax. Screening nasal swabs by PCR may not be sensitive enough to rule out dangerous exposure to anthrax spores, as a minimum of 2000 spores per sample was required for detectable amplification. As spores survived some standard DNA purification methods, special attention should be paid to laboratory safety when preparing samples possibly containing live spores.

Anthrax↗

PubMed2002

Sublethal concentrations of complement can effectively opsonize Borrelia burgdorferi.

The fate of borreliae invading a human may depend on the early innate response they induce. The interactions of human complement system and neutrophils with two strains of the Lyme borreliosis spirochete Borrelia burgdorferi were studied. Borrelia burgdorferi sensu stricto B31 (resistant to a 28% concentration of normal human serum (NHS)) and Borrelia garinii Bg A218/98 (sensitive to 7% NHS) were examined. Both strains induced neutrophil oxidative burst in a complement-dependent manner. B31 required the presence of 7% NHS, but Bg A218/98 required the presence of only 0.7% NHS for optimal induction of the burst. At all concentrations of NHS, the proportion of the spirochetes with C3bi on their surfaces and the relative amount of C3bi bound per spirochete were larger with Bg A218/98 than with B31. Bg A218/98 was able to induce an oxidative burst, when provided with serum with blocked classical pathway of complement, whereas B31 required the presence of the classical pathway. We suggest a role for the opsonizing effect of complement in controlling borreliae that are either resistant to direct killing by complement or located in the compartments of the human body at sublethal concentrations of the same.

Borrelia burgdorferi↗

PubMed2001

Early dissemination of Borrelia burgdorferi without generalized symptoms in patients with erythema migrans.

The diagnosis of erythema migrans (EM) is not always easy, and reports of culture- or PCR-confirmed diagnosis as well as reports of EM with simultaneous disseminated disease are few. Characteristics and incidence of EM in addition to frequency of early dissemination of B. burgdorferi were studied in the archipelago of South-Western Finland prospectively using questionnaires, skin biopsies and blood samples. Clinical EM was recognized in 82 patients (incidence 148/100,000 inhabitants/year). Of skin biopsy samples, 35.5% were positive by PCR (the majority B. garinii), and 21.5% by cultivation (all B. garinii). Of blood samples, 3.8% were positive by PCR, and 7.7% by cultivation. Of the patients, 30.9% were seropositive at the first visit, and 52.9% 3 weeks later. Of the patients with laboratory confirmed diagnosis, the EM lesion was ring-like in 31.8% and homogeneous in 65.9%. Dissemination of B. burgdorferi, based on culture or PCR positivity of blood samples, was detected in 11.0% of the patients. The frequency of generalized symptoms was nearly the same in patients with as in those without dissemination (22.2% vs 27.4%). Only 21.4% of the patients with culture-positive EM recalled a previous tick bite at the site of the EM lesion. We conclude that EM lesions are more often homogeneous than ring-like. B. burgdorferi may disseminate early without generalized symptoms.

Antibodies, Bacterial↗

PubMed2001

LCx Mycobacterium tuberculosis assay is valuable with respiratory specimens, but provides little help in the diagnosis of extrapulmonary tuberculosis.

BACKGROUND: Commercial nucleic acid amplification tests, designed for the detection of Mycobacterium tuberculosis DNA/RNA in respiratory samples, are often applied also in nonrespiratory specimens in order to verify the diagnosis of extrapulmonary tuberculosis. AIM. To evaluate the value of the Abbott LCx Mycobacterium tuberculosis assay for the diagnosis of pulmonary and extrapulmonary tuberculosis based on routine clinical laboratory results. METHODS: The assay was used to analyse 350 respiratory and 826 nonrespiratory specimens from 961 patients, of whom 3.6% had culture-proven tuberculosis. The results obtained by the LCx assay were compared with the records on mycobacterial isolates of the national reference laboratory and, in the case of positive findings, with clinical data. RESULTS: In comparison with culture, the sensitivity, specificity and positive/negative predictive value of the assay on respiratory specimens were 87.5%, 99.7%, 93.3% and 99.4%, respectively. With nonrespiratory specimens, the overall sensitivity, specificity and positive/negative predictive value of the LCx assay were 73.3%, 98.0%, 40.7% and 99.5%, respectively. When clinical and histological data were also included, the positive predictive value of LCx with nonrespiratory specimens was 45.8%. CONCLUSION: Critical interpretation of the nucleic acid amplification results obtained from nonrespiratory specimens is necessary in both laboratory and clinical settings.

Humans↗

PubMed2000

Immune responses to pertussis antigens eight years after booster immunization with acellular vaccines in adults.

Pertussis-specific antibody and cell-mediated immune (CMI) responses were studied in adults 8 years after booster immunization with either a bicomponent (pertussis toxin and filamentous hemagglutinin) or a monocomponent (pertactin) acellular vaccine and in age-matched healthy controls. The levels of vaccine-induced antibodies were also compared between the serum samples collected before, 1 month, 4 years, and 8 years after immunization. Over the follow-up period, geometric mean values (GMV) of antibodies to the vaccine antigens decreased in both groups of vaccinees. However, the 8-year postimmunization GMV were 3-20 times higher than preimmunization GMV (all P values <0.01). Moreover, both antibody and CMI responses to the vaccine antigens were significantly higher in the vaccinees than in the controls (all P<0.01 for antibody; all P<0.001 for CMI responses). The results show that antibody and CMI responses induced by acellular pertussis vaccines can persist for up to 8 years after booster immunization of adults primed with whole-cell vaccine.

Adhesins, Bacterial↗

PubMed2000

The expanding clinical spectrum of ocular lyme borreliosis.

OBJECTIVE: To delineate the clinical manifestations of ocular Lyme borreliosis, while concentrating on new symptoms and findings and the phase of appearance of ophthalmologic disorders. DESIGN: Observational case series. PARTICIPANTS: Ten patients with Lyme borreliosis-associated ophthalmologic findings previously reported from the Helsinki University Central Hospital in addition to 10 new cases that have since been diagnosed. INTERVENTION/TESTING: The patients underwent medical and ophthalmologic evaluation. The diagnosis of Lyme borreliosis was based on medical history, clinical ocular and systemic findings, determinations of antibodies to Borrelia burgdorferi by enzyme-linked immunosorbent assay and immunoblot analysis, the detection of DNA of B. burgdorferi by polymerase chain reaction, and exclusion of other infectious and inflammatory causes. MAIN OUTCOME MEASURES: Ocular complaints, presenting ophthalmologic findings, and the stage of Lyme borreliosis were recorded. RESULTS: Four patients presented with a neuro-ophthalmologic disorder, five had external ocular inflammation, 10 patients had uveitis, and one had branch retinal vein occlusion. One patient developed episcleritis and one patient developed abducens palsy within 2 months of the infection incident. In the remaining 14 patients in whom the time of infection was traced, the ocular manifestations appeared in the late stage of Lyme borreliosis. Two patients with a neuro-ophthalmologic disorder and one with external ocular inflammation experienced severe photophobia, whereas the main reported symptom of the patients with uveitis was decreased visual acuity. Four patients with external ocular disease and one with a neuro-ophthalmologic disorder experienced severe periodic ocular or facial pain. Retinal vasculitis developed in seven patients with uveitis. CONCLUSIONS: Lyme borreliosis can cause a variety of ocular manifestations, which develop mainly in the late stage of the disease. Photophobia and severe periodic ocular pain can be characteristic symptoms of Lyme borreliosis. In the differential diagnosis of retinal vasculitis, Lyme borreliosis should be taken into account, especially in endemic areas.

Adult↗

PubMed2000

Erythema migrans--influence of posture. Case report.

Despite widespread awareness of the most classical clinical presentation with central clearing of erythema migrans, a pathognomonic sign of infection with Borrelia burgdorferi, diagnosis of other forms of erythema migrans remains more difficult. We describe a case of a patient with secondary lesions of erythema migrans that within three months formed a complicated pattern and affected at last nearly the entire lower limb of the patient. In addition, the erythema appeared to be posture-dependent in the way that the lesion was with central clearing in the supine and with homogeneous appearance in the upright position. The borrelial infection was confirmed by PCR sequencing that detected DNA of B. afzelii in the skin biopsy specimen. The lesions disappeared during antibiotic therapy. This case shows how posture can be important in the examination of patients with a suspected erythema migrans.

Borrelia burgdorferi Group↗

PubMed2000

Borrelia burgdorferi--induced oxidative burst, calcium mobilization, and phagocytosis of human neutrophils are complement dependent.

When Borrelia burgdorferi, the spirochete causing Lyme disease, is transmitted to a human, the complement system is among the first challenges facing the bacterium. Neutrophils are crucial leukocytes in the first line of host defense against bacterial infections. To investigate the role of complement in the Borrelia-induced activation of human neutrophils, oxidative burst, calcium mobilization, and phagocytosis induced by three subspecies of B. burgdorferi were studied. Each subspecies induced all observed neutrophil functions in a complement-dependent manner. Serum-derived factors bound to the surface of B. burgdorferi were found to be essential for the induction of the oxidative burst. The CD11b chain of CR3 was found to participate in the oxidative burst and calcium mobilization induced by B. burgdorferi.

Borrelia burgdorferi Group↗

PubMed2000

Rapid differentiation of Borrelia garinii from Borrelia afzelii and Borrelia burgdorferi sensu stricto by LightCycler fluorescence melting curve analysis of a PCR product of the recA gene.

To differentiate the Borrelia burgdorferi sensu lato genospecies, LightCycler real-time PCR was used for the fluorescence (SYBR Green I) melting curve analysis of borrelial recA gene PCR products. The specific melting temperature analyzed is a function of the GC/AT ratio, length, and nucleotide sequence of the amplified product. A total of 32 DNA samples were tested. Of them three were isolated from B. burgdorferi reference strains and 16 were isolated from B. burgdorferi strains cultured from Ixodes ricinus ticks; 13 were directly isolated from nine human biopsy specimens and four I. ricinus tick midguts. The melting temperature of B. garinii was 2 degrees C lower than that of B. burgdorferi sensu stricto and B. afzelii. Melting curve analysis offers a rapid alternative for identification and detection of B. burgdorferi sensu lato genospecies.

Animals↗

PubMed2000

Ligase chain reaction assay is clinically useful in the discrimination of smear-positive pulmonary tuberculosis from atypical mycobacterioses.

We evaluated the usefulness of the ligase chain reaction (LCR) (Abbott LCx Mycobacterium tuberculosis assay) during the initial diagnosis of tuberculosis. LCx was carried out in parallel with conventional methods for the analysis of clinical samples. Out of 86 patients who were examined clinically, 53 were suspected of having pulmonary tuberculosis, eight had residual X-ray scars from previous tuberculosis and 25 served as asymptomatic controls. Ten bronchoscopy samples and 237 sputum samples were analysed by direct microscopy, culture and LCx. All 11 smear-positive and two of three smear-negative tuberculosis patients had at least one LCx-positive specimen. All samples that were both LCx- and smear-positive were culture-positive for M. tuberculosis. The smear-positive samples from the five patients with atypical mycobacteriosis were LCx-negative. There were three false-positive results: one in a smear-negative sample from a patient with M. malmoense infection and two from two pneumonia patients. All samples from controls and patients with previous tuberculosis were LCx-negative. The sensitivity, specificity and the positive and negative predictive values of LCx in patient analysis were 92.9%, 95.8%, 81.3% and 98.6%, respectively. LCx assay of M. tuberculosis is useful in rapid confirmation of tuberculosis or atypical mycobacteriosis from a smear-positive sample and may aid in diagnosing smear-negative tuberculosis.

Bacteriological Techniques↗

PubMed1999

Line probe assay in the rapid detection of rifampin-resistant Mycobacterium tuberculosis directly from clinical specimens.

The sensitivity of a PCR-based line probe assay (Inno-LiPA Rif. TB Assay; Innogenetics NV Zwijndrecht, Belgium) was studied by using nested-PCR technique. A total of 75 specimens, representing various body locations from 70 suspected tuberculosis patients were obtained. LiPA yielded 30 Mycobacterium tuberculosis complex positive results (sensitivity 58.8%, compared with final diagnoses) whereas culture for M. tuberculosis was positive in 18 specimens (sensitivity 35.3%). Genotypic rifampin resistance testing by LiPA showed that 7 specimens contained rpoB mutations associated with RMP resistance, and sequencing data of the rpoB gene and LiPA patterns agreed in 29 of 30 M. tuberculosis positive specimens (96.7%). This indicates reliable performance, which makes the test suitable for the rapid determination of resistance to rifampin directly in clinical samples. However, the best results are obtained if LiPA is combined with conventional staining and culture methods.

Antibiotics, Antitubercular↗

PubMed1999

Cell-mediated immune responses to antigens of Bordetella pertussis and protection against pertussis in school children.

BACKGROUND: Increasing evidence suggests that cell-mediated immunity (CMI) is involved in immune response against Bordetella pertussis. However, there are practically no studies evaluating the significance of pertussis-specific CMI in relation to protection against clinical pertussis. METHODS: An outbreak of pertussis was studied prospectively in 13-year-old pupils in a rural school. B. pertussis infection was diagnosed by culture, microagglutination and enzyme immunoassay serology with the use of pertussis toxin, filamentous hemagglutinin and pertactin as antigens. Pertussis-specific CMI responses were assessed by in vitro proliferation assay of peripheral blood mononuclear cells. RESULTS: At the initial sampling 7 of 22 children had symptoms suggestive of pertussis and 15 were asymptomatic. Of the latter 3 remained healthy, 8 were later confirmed to have had asymptomatic infection, 3 developed laboratory-confirmed pertussis and 1 developed cough without laboratory evidence of pertussis. Initial in vitro proliferations of peripheral blood mononuclear cells induced by pertussis toxin, filamentous hemagglutinin and/or pertactin were positive in all 3 healthy children, in 6 of 8 children who had asymptomatic infection, but in none of the 3 children who later developed pertussis. Although some children who remained healthy had high values of antibodies, no clear association was found between initial serum antibody values and clinical outcome. CONCLUSIONS: These preliminary data suggest that CMI may have an important role in protection against clinical pertussis but do not exclude a role for antibodies. Furthermore the results stress a multifactorial nature of the immune protection against B. pertussis.

Adolescent↗

PubMed1999

pncA mutations in pyrazinamide-resistant Mycobacterium tuberculosis isolates from northwestern Russia.

Thirty-six pyrazinamide-resistant and eight pyrazinamide-susceptible Mycobacterium tuberculosis isolates from Russia were analyzed for their pncA mutations. Thirty-one (86.1%) of the resistant isolates had a mutation either in pncA or upstream of the gene. Twenty of the 23 different mutations found in this study had not been described earlier. pncA genotype correlated well with pyrazinamidase activity and BACTEC 460 susceptibility test results.

Amidohydrolases↗

PubMed1999

Outcomes of Bordetella infections in vaccinated children: effects of bacterial number in the nasopharynx and patient age.

Five outbreaks of infection (three pertussis, one parapertussis, and one mixed) in schools were studied prospectively. Nasopharyngeal swabs were obtained from a total of 697 children for culture of Bordetella organisms. Of 50 vaccinated children with culture-confirmed Bordetella infections (29 with pertussis and 21 parapertussis), 40 were symptomatic and 10 remained symptom-free. Smaller numbers of colonies were recovered from the nasopharyngeal swabs of the asymptomatic children than from those of the symptomatic children. Older children had longer durations of illness than younger ones. Our results indicate that during outbreaks children who do not develop disease may have small amounts of Bordetella organisms in their nasopharynges and/or better immune defenses against the disease.

Adolescent↗

PubMed1999

Prevalence of Borrelia burgdorferi in Ixodes ricinus ticks in urban recreational areas of Helsinki.

Lyme borreliosis, an infection caused by the tick-borne spirochete Borrelia burgdorferi, is a major health problem for populations in areas of endemicity in the Northern Hemisphere. In the present study we assessed the density of ticks and the prevalence of B. burgdorferi sensu lato among ticks in popular urban recreational areas of Helsinki, Finland. Altogether 1,688 Ixodes ricinus ticks were collected from five areas located within 5 km of the downtown section of Helsinki, and 726 of them (303 nymphs, 189 females, and 234 males) were randomly chosen for laboratory analysis. The midguts of the ticks were divided into three pieces, one for dark-field microscopy, one for cultivation in BSK-II medium, and one for PCR analysis. Ticks were found in all the study areas; their densities varied from 1 to 36 per 100 m along which a cloth was dragged. The rate of tick infection with B. burgdorferi sensu lato varied from 19 to 55%, with the average being 32%. Borellia afzelii was the most predominant genospecies in all the areas, and no B. burgdorferi sensu stricto isolates were detected. Only two ticks were concurrently infected with both B. afzelii and Borrelia garinii. Dark-field microscopy gave more positive results for B. burgdorferi than did cultivation or PCR analysis. However, the agreement between all three methods was fairly good. We conclude that Lyme borreliosis can be contracted even in urban environments not populated with large mammals like deer or elk. The disease should be taken into account in the differential diagnosis of certain symptoms of patients from these areas, and the use of measures to improve the awareness of the general population and health care officials of the risk of contracting the disease is warranted.

Animals↗