Torsten Berglund

Molecular Epidemiology of Neisseria gonorrhoeae: Sequence Analysis of the porB Gene Confirms Presence of Two Circulating Strains

ABSTRACT The phenotypic and genotypic characteristics of Neisseria gonorrhoeae strains fluctuate over time both locally and globally, and highly discriminative and precise characterization of the strains is essential. Conventional characterization of N. gonorrhoeae strains for epidemiological purposes is mostly based on phenotypic methods, which have some inherent limitations. In the present study sequence analysis of porB1b gene sequences was used for examination of the genetic relationships among N. gonorrhoeae strains. Substantial genetic heterogeneity was identified in the porB genes of serovar IB-2 isolates (8.1% of the nucleotide sites were polymorphic) and serovar IB-3 isolates (5.2% of the nucleotide sites were polymorphic) as well as between isolates of different serovars. The highest degree of diversity was identified in the gene segments encoding the surface-exposed loops of the mature PorB protein. Phylogenetic analysis of the porB1b gene sequences confirmed previous findings that have indicated the circulation of one N. gonorrhoeae strain each of serovar IB-2 and serovar IB-3 in the Swedish community. These strains caused the majority of the cases in two domestic core groups comprising homosexual men and young heterosexuals, respectively, and were also detected in other patients. The phylogenetic analyses of porB gene sequences in the present study showed congruence, but not complete identity, with previous results obtained by pulsed-field gel electrophoresis of the same isolates. In conclusion, porB gene sequencing can be used as a molecular epidemiological tool for examination of genetic relationships among emerging and circulating N. gonorrhoeae strains, as well as for confirmation or discrimination of clusters of gonorrhea cases.

Lymphogranuloma Venereum Prevalence in Sweden among Men Who Have Sex with Men and Characterization of Chlamydia trachomatis ompA Genotypes

ABSTRACT An outbreak of lymphogranuloma venereum (LGV) infections has recently been reported from The Netherlands and other European countries. The Swedish surveillance system has identified three LGV cases since 2004, all with clinically suspected infection in men who have sex with men (MSM). In order to assess the prevalence of LGV in a high-risk group of MSM and include clinically atypical cases, retrospective analysis of 197 Chlamydia trachomatis-infected men was performed. Sequencing of the ompA gene showed a different serotype distribution compared to recent Swedish studies in heterosexual populations. The most common types were G (45%), D (27%), and J (26%), whereas the normally predominant type E accounted for only 4% of the chlamydia cases. Furthermore, certain ompA genotype variants of the dominant serotypes were highly prevalent among MSM, and the reason for this is discussed. No additional case of LGV was detected by retrospective analysis of the high-risk MSM population. This indicates that, thus far, LGV in Sweden is only a result of sporadic import from infected MSM clusters abroad.

One year of Neisseria gonorrhoeae isolates in Sweden: the prevalence study of antibiotic susceptibility shows relation to the geographic area of exposure

The aim of this study was to compare epidemiological data with antibiotic susceptibility patterns, so as to characterize the risk of infection with a highly resistant Neisseria gonorrhoeae strain. N. gonorrhoeae strains isolated in Sweden from February 1998 through January 1999 were tested for antibiotic susceptibility. Epidemiological data were received from each clinician reporting a case of gonorrhoea and these data were linked to the N. gonorrhoeae strains. A total of 348 N. gonorrhoeae isolates, representing 89% of all Swedish cases diagnosed during the 12-month period, were tested for antibiotic susceptibility. Of all isolates, 24% were β-lactamase-producing, and 18% had decreased susceptibility to ciprofloxacin (MIC>0.064 mg/l). All isolates were fully susceptible to ceftriaxone and spectinomycin. More than 99% of the isolates were fully susceptible to azithromycin. The antibiotic susceptibility varied with the places where patients were exposed to infection. When exposed in Asia, 63% of the isolates showed reduced susceptibility to ciprofloxacin, compared with 0-8.5% of the isolates from patients exposed in other places (RR=8.5, P<0.001). Ciprofloxacin cannot be recommended as the first choice of treatment if the place of exposure was in Asia.

Epidemiology of the reemergence of gonorrhea in Sweden.

Background After many years of decline, the incidence of gonorrhea in Sweden reached an all-time low of 2.4 cases per 100,000 inhabitants in 1996; however, the incidence has been increasing since 1997. Goal To describe the reemergence of gonorrhea in Sweden using clinical epidemiologic data and microbiologic characterization of isolated strains of Neisseria gonorrhoeae. Study Design N gonorrhoeae strains isolated in Sweden from February 1998 to January 1999 were serotyped and an epidemiologic data questionnaire was sent to each clinician reporting a case of gonorrhea. Results Epidemiologic and microbiologic data were obtained for 357 cases (91% of all cases diagnosed during the period). Domestic cases had significantly increased since 1997. Serovar IB-3 was the most common isolate in domestic cases of heterosexually exposed teenagers, and serovar IB-2 was the most frequent isolate in domestic cases of homosexually exposed men. Of the imported cases, 47% were exposed in Asia and 6.5% were exposed in Eastern Europe. Conclusion The increase of gonorrhea in Sweden is due to an increase of domestic cases. Heterosexual teenagers and homosexual men were identified as core groups infected by different serovars of N gonorrhoeae.

Molecular epidemiology of Neisseria gonorrhoeae– identification of the first presumed Swedish transmission chain of an azithromycin-resistant strain†

In the present study, 10 azithromycin‐resistant Neisseria gonorrhoeae isolates from 6 Swedish male patients in 2004, 3 sporadic Swedish azithromycin‐resistant N. gonorrhoeae isolates from recent years and one Swedish N. gonorrhoeae isolate from 2003 that was susceptible to azithromycin but assigned the same serological variant (serovar), i.e. IB‐37, as the isolates from 2004 were included. The isolates were characterized phenotypically using antibiograms and serovar determination and genetically with pulsed‐field gel electrophoresis (PFGE), entire porB gene sequencing and N. gonorrhoeae multiantigen sequence typing (NG‐MAST). The epidemiological information and the results of the thorough phenotypic characterisation and genetic characterisation identified the first presumed domestic transmission of one azithromycin‐resistant N. gonorrhoeae strain in Sweden in 2004. This stresses the need for continuous surveillance of the antibiotic susceptibility of N. gonorrhoeae in order to identify emergence of new resistance, monitor the changing patterns of the susceptibility, and be able to update treatment recommendations on a regular basis.

Antiretroviral treatment of human immunodeficiency virus infection : Swedish recommendations

The Swedish guidelines (SwG) for treatment of human immunodeficiency virus (HIV) infection have several important roles. A major task involves the promotion of a uniformly high standard of care in all HIV treatment clinics in Sweden and the identification of strengths, weaknesses and relevance of recent research findings. CD4+ T-cell counts<200 cells/μl are clear indications for the initiation of treatment, whereas high viral loads serve as an indication for increased vigilance rather than a criterion for therapy. It is recommended that the first regimen consists of 2 nucleoside reverse transcriptase inhibitors in combination with 1 protease inhibitor or 1 non-nucleoside reverse transcriptase inhibitor. The definition of treatment failure is rigorous. Treatment change should be considered if the viral load has not fallen by at least 1.5 log in 4 weeks or is undetectable within 3-4 months. Resistance testing is endorsed at primary infection, in the event of treatment failure and in pregnant women. Interaction with experts in HIV resistance testing is emphasized. Therapeutic drug monitoring is advocated. Patients with treatment failure should be handled individually and the decision on therapeutic strategy should be based on treatment history, resistance testing and other clinical facts. The SwG do not give recommendations for some important issues such as prolonged drug holidays and preferences in initial treatment regimens. More scientific data are likely to be available soon and the SwG will be refined accordingly. The present guidelines are translated from Swedish; they are published on the Medical Products Agency (MPA) and Swedish Reference Group for Antiviral Therapy (RAV) websites (www.mpa.se and www.rav.nu.se), including 7 separate papers based on a thorough literature search. A complete reference list is available on request from the MPA.

Pulsed-field gel electrophoresis as an epidemiologic tool for Neisseria gonorrhoeae: identification of clusters within serovars.

Background The increasing incidence of gonorrhea in Sweden in 1998 was due to mostly domestic cases. Among these, two core groups were identified: homosexual men with serovar IB-2 and young heterosexuals with serovar IB-3. Goals To explore the genetic homogeneity/heterogeneity within the predominant serovars, IB-2 and IB-3, of Neisseria gonorrhoeae in Sweden by pulsed-field gel electrophoresis (PFGE) and to compare these results to epidemiologic information, as well as examine the genetic diversity within and between the 25 other represented serovars of N gonorrhoeae. Study Design By PFGE, 237 N gonorrhoeae isolates were examined, and the results were compared with epidemiologic data for the IB-2 and IB-3 isolates. Results In 79% of the domestic IB-2 cases involving homosexuals and 66% of the domestic IB-3 cases involving young heterosexuals, the isolates were genetically indistinguishable by PFGE. A high genetic diversity was identified within and between the 27 included serovars. Conclusions Examination by means of PFGE indicated that one N gonorrhoeae clone each of the serovars IB-2 and IB-3 created the majority of the two core groups of domestic cases.

Two cases of oral-to-genital HIV-1 transmission.

The identi® cation of the human immunode® ciency virus (HIV-1) as the cause of the acquired immunode® ciency syndrome (AIDS) and the development of speci® c HIV-1 antibody assays made it possible to evaluate risk factors for HIV-1 infection in gay men. Epidemiological studies in 1984 identi® ed a large number of homosexual partners and receptive anal intercourse to be risk factors for HIV-1 seropositivity in gay men1. Similarly, the Multicenter AIDS Cohort Study (MACS) study found the practice of receptive as well as insertive anal intercourse to be strongly associated with HIV-1 infection2. Whether HIV-1 can be transmitted by oral sex has been controversial and very few cases of proven genito-oral or orogenital transmissions of HIV-1 have been documented. Hence, most `safe sex’ campaigns targeting gay men have focused on unprotected anal intercourse as the main risk. However, in 1984, HIV-1 positivity was detected in 29% of subjects reporting no receptive anal intercourse during the preceding year1. We have in our practice come across cases of sexually transmitted HIV-1 infection in gay men who consistently claim that they never had anal intercourse, receptive or insertive. The following 2 case reports exemplify oral-to-genital HIV-1 transmission. In the ® rst case (patients A and B) there were no genital or oral ulcers or any other identi® able concurrent local infections that could have facilitated the HIV-1 transmission. The patients’ concordant sexual histories and the genetic similarities of the 2 viral strains are striking. In patient C a penile skin damage could have facilitated the oral-to-genital HIV-1 transmission. In Sweden HIV-1 infection is a noti® able disease and partner noti® cation is legally regulated3. In our clinic the partner noti® cation work is speci® cally targeted to serve gay men and is routinely performed by specially trained social workers4. In our experience patients are usually highly motivated to participate in this, regardless of legal obligations.

The epidemiology of gonorrhea among men who have sex with men in Stockholm, Sweden, 1990-2004.

Objectives: The objectives of this study were to analyze the spread of gonorrhea in men who have sex with men (MSM) in Stockholm regarding serovars, HIV status, and site of infection and to compare the distribution of serovars among HIV-positive and HIV-negative MSM. Study Design: Clinical and epidemiologic data were collected for all MSM diagnosed with gonorrhea in 1990 to 2004 at a clinic primarily serving MSM. Neisseria gonorrhoeae strains were serotyped. Results: A total of 1,039 isolates from 840 gonorrhea episodes in 721 patients were included. A sharp increase was seen during the 2000s. Ten percent of the cases were HIV-positive. The proportion of pharyngeal infections increased significantly (P <0.001) from 15% to 38% during the last 7 years. A great variation of serovars (n = 66) was observed, but only 5 were present >10 years. There was a significant difference (P = 0.001) in distribution of serovars correlated to HIV status. Conclusion: Gonorrhea is a marker for HIV infection in MSM, but the increase in gonorrhea may be associated with genital–oral sexual practice rather than with high-risk sexual practice.