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Characterization of Chlamydia trachomatis omp1 genotypes among sexually transmitted sisease patients in Sweden
Department of Clinical Microbiology and Immunology, Örebro Medical Centre Hospital, Örebro.
Outpatient Sexually Transmitted Disease Clinic, Department of Dermatovenereology, Örebro Medical Centre Hospital, Örebro.ORCID iD: 0000-0001-8336-9767
Department of Clinical Microbiology and Immunology, Örebro Medical Centre Hospital, Örebro.
Outpatient Sexually Transmitted Disease Clinic, Department of Dermatovenereology, Örebro Medical Centre Hospital, Örebro.
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2001 (English)In: Journal of Clinical Microbiology, ISSN 0095-1137, E-ISSN 1098-660X, Vol. 39, no 11, 3915-3919 p.Article in journal (Refereed) Published
Abstract [en]

A method for detection and genotyping of genital Chlamydia trachomatis infections based on omp1 gene amplification and sequencing was developed. DNA was extracted from urogenital or urine samples using a Chelex-based method, and an approximately 1,100-bp-long fragment from the omp1 gene was directly amplified and sequenced. Genotyping was performed by BLAST similarity search, and phylogenetic tree analysis was used to illustrate the evolutionary relationships between clinical isolates and reference strains. The method was used to determine the genotypes ofC. trachomatis in 237 positive urogenital and/or urine specimens collected at a Swedish sexually transmitted disease clinic during 1 year. The most common genotypes corresponded to serotypes E (47%) and F (17%). The omp1 gene was highly conserved for genotype E (106 of 112 samples without any mutation) and F (41 of 42 samples without any mutation) strains but appear slightly less conserved for genotypes G (n = 6) and H (n = 6), where the sequences displayed one to four nucleotide substitutions relative to the reference sequence. Genotyping of samples collected at the follow-up visit indicated that two patients had become reinfected, while three other patients suffered treatment failure or reinfection. One woman appeared to have a mixed infection with two different C. trachomatis strains. Thisomp1 genotyping method had a high reproducibility and could be used for epidemiological characterization of sexually transmitted Chlamydia infections.

Place, publisher, year, edition, pages
2001. Vol. 39, no 11, 3915-3919 p.
National Category
Medical and Health Sciences
URN: urn:nbn:se:liu:diva-25864DOI: 10.1128/​JCM.39.11.3915-3919.2001Local ID: 10301OAI: diva2:246412
Available from: 2009-10-08 Created: 2009-10-08 Last updated: 2015-09-22
In thesis
1. Urethritis and cervicitis with special reference to Chlamydia trachomatis and Mycoplasma genitalium: diagnostic and epidemiological aspects
Open this publication in new window or tab >>Urethritis and cervicitis with special reference to Chlamydia trachomatis and Mycoplasma genitalium: diagnostic and epidemiological aspects
2004 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

The aim of this thesis was to elucidate urethritis and cervicitis and the possible causes with special reference to Chlamydia trachomatis and Mycoplasma genitalium. Despite mandatory partner notification legislated in 1988, the incidence of C trachomatis infection in Sweden has undergone a 10% annual increase since 1997, following a decline in the early 1990s. Nonchlamydial-non-gonococcal urethritis (and cervicitis) (NCNGU) is more common than chlamydial infection and gonorrhoea at Sexually transmitted disease (SID) clinics. Mycoplasma genitalium, originally isolated in 1980, is one probably important cause of NCNGU.

Specimens from men and women infected with C trachomatis who attended the Örebro STD-clinic (1999-2000) were genotyped by sequencing of the omp 1, which encodes the major outer membrane protein (MOMP) (I, II). Both invasive and first void urine (FVU) specimens (n=237) were successfully sequenced from 231 C trachomatis-positive individuals (96 women and 135 men). Genotype E was the most common strain (47%) followed by F (17%) and K (9%). The prevalence of Ba, D, D/B-120, D/B-185, G, H, Ia and J genotypes was 0.4 to 6%. There were few gap mutations compared with reference strains. 161 sexual networks comprising 688 individuals were compiled. Specimens were sequenced from at least two patients in 47 of 161 networks. In seven of these 47 networks (15%) there were discrepant genotypes. At the follow-up visit five of 204 individuals (2%) were still C trachomatis-positive. Two harboured a new genotype and thus had contracted a new C trachomatis infection. Partner notification was successful in only 30 of 161 networks (19%), meaning that all elicited partners were tested and transmission of infection ceased. The main reason for non-success was insufficient information for partner identification from the index patients and, if the partner attended another clinic, the results of the C trachomatis test were prohibited by Swedish law from being revealed to the tracer.

Microscopic signs, symptoms of infection and prevalence of C trachomatis and M genitalium were compared among men and women attending the Örebro STD-clinic in 2000 (III, IV). In a study performed in 2002, 59 young women invited to the national cervical cancer-screening program were tested for C trachomatis and M genitalium (IV). There was no statistically significant difference in microscopic signs in men or women infected with either of the bacteria. Women infected with C trachomatis or M genitalium more often had microscopic signs of infection than those women in the cancer screening group without infection, and the difference was statistically significant (IV). Symptomatic urethritis was more prevalent in M genitalium than in C trachomatis infected men (III). The prevalence of C trachomatis and M genitalium in male STD-attendees was 12% and 7%, respectively. In female STD-attendees the corresponding figures were 10% and 6%, respectively, whereas only one woman in the screening group was C trachomatis-positive and none was infected with M genitalium (IV). Both C trachomatis and M genitalium were found significantly more often in partners of men and partners of women with the corresponding infection, than in partners of men with a non specific urethritis (NSU) or women with a non-specific urethritis/cervicitis. These studies show that M genitalium is a common infection among STD-clinic attendees and that it is not a widespread commensal bacterium in society.

In an open treatment pilot study (V) in men and women infected with M genitalium, the standard treatment for urethritis and cervicitis, i.e. tetracycline, was compared with azithromycin 500 mg the first day and 250 mg the following four days. Tetracyclines did not eradicate M genitalium in 71% of the women and in 63% of the men, whereas all who were treated with azithromycin were M genitalium negative at the follow-up visit. Randomised controlled trials (RCT) are needed to study azithromycin in different dosages.

Abstract [sv]

Denna avhandling vill belysa urethrit och cervicit orsakad av sexuellt överrörd sjukdom med speciellt fokus på Chlamydia trachomatis och Mycoplasma genitalium. Trots skyldighet, enligt Smittskyddslagen, att vid klamydia spåra sexuella partners till dem med infektion har antalet rapporterade klamydiafall till Smittskyddsinstitutet (SMI), efter en markant nedgång åren 1989 till 1994, ökat med cirka 10 % årligen sedan 1997. Urethrit och cervicit som orsakas av andra mikroorganismer än C traehomalis och Neisseria gonorrhoeae utgör mer än hälften av alla fall med urethrit och cervicit på en STD-mottagning. Mycoplasma genitalium, en bakterie som upptäcktes 1980, är troligen en viktig orsak.

I arbete I och II studerades män och kvinnor som sökt STD-mottagningen vid Universitetssjukhuset Örebro (1999-2000) och som hade en genital klamydiainfektion. En metod för att sekvensera den gen (omp 1) som kodar för ett protein i bakteriens yttermembran (MOMP) utvecklades. Metoden var framgångsrik på både invasiva prover från cervix och urethra liksom urinprov och 237 prover kunde sekvenseras från 231 personer (96 kvinnor och 135 män). Alla kända genotyper för genital klamydiainfektion fanns representerade, med en uttalad ökad förekomst av genotyp E (47%), följt av F (17%). Den genetiska stabiliteten var mycket hög. I 7 av 47 (15%) sexuella nätverk (kontaktspårningskedjor) förekom diskrepanta genotyper. 90% (n=204) av de 226 som primärt sökt STD-mottagningen (93 kvinnor och 133 män) kom på återbesök och 2% (5/204) var klamydiapositiva, varav två med annan klamydiagenotyp än vid första besöket. Sanmmanlagt 161 nätverk med 688 personer hittades. Lyckad kontaktspårning, där alla individer i ett nätverk undersökts, förekom endast i 19% (30/161) av nätverken. Orsaker till misslyckande var bristfälliga uppgifter om partners från indexpatienter och att partners sökt till annan mottagning där testresultatet förblev okänt för partnerspåraren, pga sekretesslagen.

I arbete III och IV jämfördes, mikroskopiska tecken på infektion, symptom och forekorost mellan C trachomatis och Mycoplasma genitalium infektion bland män (III) och kvinnor (IV) som sökte STD-mottagningen (2000). En undersökning av 59 unga kvinnor, kallade för cellprovskontroll (screening), där prover för C trachomatis, M genitalium och mikroskopi togs genomfordes 2002 (IV). Det fanns ingen signifikant skillnad av mikroskopiska tecken på infektion mellan dem infekterade med C trachomatis eller med M genitalium. Däremot hade kvinnor med C trachomatis eller M genitalium infektion signifikant oftare mikroskopiska tecken på infektion än kvinnor (n=58) utan någon av dessa infektioner i jämförelsegruppen. Män med M genitalium infektion hade signifikant oftare symptom än män infekterade med klamydia. Någon signifikant skillnad fanns inte i motsvarande grupper hos kvinnor. Prevalensen av M genitalium och C trachomatis infektion bland män var 7% respektive 12% (III). Av kvinnorna som sökte på STD-mottagningen hade 10% C trachomatis och 6% M genitalium infektion, medan endast en respektive ingen av de 59 kvinnorna i jämförelsegruppen var C trachomatis eller M genitalium positiva (IV). Partners till män respektive kvinnor med C trachomatis eller M genitalium infektion var signifikant oftare infekterade med motsvarande bakterie (67% respektive 63% (=kvinnliga partners) och 59%, respektive 56% (manliga partners)) än partners till patienter med urethrit eller cervicit, men med negativt test för M genitalium och C trachomatis (p<0.001). Dessa arbeten visar att M genitalium är vanligt förekommande, på STD-mottagningar, men att den inte förekommer allmänt och att den som klamydia ofta ger infektionstecken.

I en öppen pilotbehandlingsstudie (arbete V) av M genitalium infektion, där sedvanlig tetracyklinbehandling jämfördes med azithromycin i fem dygn, visades att tetracyklin har en otillräcklig effekt, medan azithromycin tycks fungera. Randomiserade kontrollerade behandlingsstudier (RCT) behövs.

Place, publisher, year, edition, pages
Linköping: Linköpings universitet, 2004. 46 p.
Linköping University Medical Dissertations, ISSN 0345-0082 ; 858
National Category
Medical and Health Sciences
urn:nbn:se:liu:diva-24390 (URN)6483 (Local ID)91-7373-829-8 (ISBN)6483 (Archive number)6483 (OAI)
Public defence
2004-10-01, Wilandersalen, Universitetssjukhuset, Örebro, 13:00 (Swedish)
Available from: 2009-10-07 Created: 2009-10-07 Last updated: 2015-09-22Bibliographically approved

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