Rapid spread of Neisseria gonorrhoeae ciprofloxacin resistance due to a newly introduced resistant strain in Nuuk, Greenland, 2012-2015: a community-based prospective cohort study.

OBJECTIVES: To determine the antimicrobial susceptibility and genotype distribution of Neisseria gonorrhoeae strains isolated from a cohort of patients in Nuuk, Greenland in order to assess the risk of rapid spread in the event of introduction of new strains. METHODS: Gonococcal isolates (n=102) obtained from a prospective cohort study of ciprofloxacin resistance were collected between March 2012 and February 2013. Etest minimal inhibitory concentrations (MICs) were determined for ciprofloxacin, azithromycin, ceftriaxone, penicillin, tetracycline, spectinomycin and gentamicin. All isolates were subjected to molecular typing using N. gonorrhoeae multiantigen sequence typing (NG-MAST). After the introduction of a ciprofloxacin-resistant strain in early 2014, an additional 18 isolates were characterised. RESULTS: During the study period, all 102 isolates were fully susceptible to ciprofloxacin (≤0.03 mg/L), azithromycin, spectinomycin, gentamicin and ceftriaxone. 10 different NG-MAST types circulated in Nuuk but 7 were found as single isolates, and 3 of the 7 belonged to 1 of the 3 major genogroups (G210, G9816 and G9817) together comprising 96% of the 102 isolates. ST210 accounted for 55% of the 102 strains. The newly introduced ciprofloxacin resistant strain belonged to ST2400 and dominated the population with 59% resistant strains within 6 months after its introduction. All G2400 strains had MICs≥2 mg/L. CONCLUSIONS: Introduction of a ciprofloxacin-resistant strain into a very homogeneous N. gonorrhoeae population led to an explosive spread of the resistant clone, probably as a result of large sexual networks suggested by the strain homogeneity. Careful surveillance of antimicrobial susceptibility is essential to avoid widespread treatment failure in closed populations.

Implications of differential age distribution of disease-associated meningococcal lineages for vaccine development.

New vaccines targeting meningococci expressing serogroup B polysaccharide have been developed, with some being licensed in Europe. Coverage depends on the distribution of disease-associated genotypes, which may vary by age. It is well established that a small number of hyperinvasive lineages account for most disease, and these lineages are associated with particular antigens, including vaccine candidates. A collection of 4,048 representative meningococcal disease isolates from 18 European countries, collected over a 3-year period, were characterized by multilocus sequence typing (MLST). Age data were available for 3,147 isolates. The proportions of hyperinvasive lineages, identified as particular clonal complexes (ccs) by MLST, differed among age groups. Subjects <1 year of age experienced lower risk of sequence type 11 (ST-11) cc, ST-32 cc, and ST-269 cc disease and higher risk of disease due to unassigned STs, 1- to 4-year-olds experienced lower risk of ST-11 cc and ST-32 cc disease, 5- to 14-year-olds were less likely to experience ST-11 cc and ST-269 cc disease, and ≥25-year-olds were more likely to experience disease due to less common ccs and unassigned STs. Younger and older subjects were vulnerable to a more diverse set of genotypes, indicating the more clonal nature of genotypes affecting adolescents and young adults. Knowledge of temporal and spatial diversity and the dynamics of meningococcal populations is essential for disease control by vaccines, as coverage is lineage specific. The nonrandom age distribution of hyperinvasive lineages has consequences for the design and implementation of vaccines, as different variants, or perhaps targets, may be required for different age groups.

Sequence-based typing of Mycoplasma genitalium reveals sexual transmission.

Mycoplasma genitalium causes male nonchlamydial, nongonococcal urethritis and is associated with cervicitis and pelvic inflammatory disease in women. Epidemiological studies indicate that M. genitalium is sexually transmitted, and the aim of the present study was to further substantiate this by means of a DNA typing system. A typing assay based on a diagnostic mgpB gene PCR was developed, evaluated, and applied directly to urogenital specimens. The assay had a low limit of detection and hence a high typeability. Sequences of isolates from 52 unrelated patients were divided into 29 different sequence types, giving a discriminatory index of 0.95. Two to six M. genitalium-positive specimens were collected from each of 44 patients over a median interval of 56 days (range, 11 to 1,395). Forty had the same sequence type in consecutive specimens. Specimens collected from two men were repeatedly positive at intervals of 472 and 1,395 days, respectively, but the sequence types had changed. A new strain was introduced in one sexual dyad, and the sequence types changed subsequently. Seventy-nine M. genitalium-positive specimens from 19 couples were investigated, and all partners initially had concordant sequence types, but one couple had discordant types at one time point before a newly introduced strain took over. The present typing system is simple and reproducible and has an excellent discriminatory capacity which might prove useful in studies of sexual networks and for evaluation of treatment failures. In the laboratory, this system may document the uniqueness of newly isolated M. genitalium strains.

Sexually transmitted infections in rural Madagascar at an early stage of the HIV epidemic: a 6-month community-based follow-up study.

BACKGROUND AND OBJECTIVES: Sexually transmitted infections (STIs) in Madagascar have primarily been monitored in selected groups of patients attending STI clinics in major cities as part of the HIV surveillance program in Madagascar. GOAL OF THE STUDY: The aim of the study was to provide complementary data related to STI prevalence in a general rural population. STUDY DESIGN: STIs were investigated in 643 subjects aged 15 to 49 years as part of a cross-sectional morbidity study of urogenital schistosomiasis. Infection rates were reassessed 3 weeks and 6 months after systematic STI treatment at baseline. RESULTS: Neisseria gonorrhoeae (Ng), Chlamydia trachomatis (Ct), Mycoplasma genitalium (Mg), Trichomonas vaginalis (Tv), and/or antibodies to Treponema pallidum (Tp) were diagnosed in 125 (37.5%) of 333 women and in 83 (26.8%) of 310 men. In addition, 49% of the women and 28% of the men were infected with herpes simplex virus-2. Six (0.9%) subjects were found HIV-antibody positive. Between the 3-week and 6-month follow-up surveys Ng, Ct, and/or Mg prevalence increased most prominently in women aged 15 to 24 years. CONCLUSION: Study findings suggest that rural areas in Madagascar should be as closely monitored and assisted in STI and HIV control as their urban counterparts. Following the current consensus, young adults should constitute a priority target group in the control programs.

Chlamydia antibody response in healthy volunteers immunized with nonchlamydial antigens: a randomized, double-blind, placebo-controlled study.

Serological analysis is often used for the diagnosis of chlamydial infections. However, an increase in Chlamydia antibodies has been reported in patients with parvovirus and Mycoplasma infections. Whether this antibody response is the result of dual infection or nonchlamydial antigen stimulation is unknown. In a randomized study, 48 healthy volunteers either were immunized against yellow fever, polio, diphtheria, and tetanus (the group receiving intervention with nonchlamydial antigen) or received saline injections (the placebo group). The change in antibody levels was compared between the 2 groups. The Chlamydia recombinant lipopolysaccharide enzyme-linked immunosorbent assay (Medac) showed an increase in the antibody titer in the intervention group, compared with that in the control group (for immunoglobulin M, P=.004; for immunoglobulin A, P=.038; and for immunoglobulin G, P=.056), but no differences between study groups was found when the C. pneumoniae enzyme immunoassay (EIA; ThermoLabsystems), the C. pneumoniae EIA (Medac), and the microimmunofluorescence test (MRL) were used. An increase in antibodies to Chlamydia organisms can be measured after exposure to nonchlamydial antigens, depending on the test used.

Neisseria meningitidis phenotypic markers and septicaemia, disease progress and case-fatality rate of meningococcal disease: a 20-year population-based historical follow-up study in a Danish county.

The incidence rate (IR) and case-fatality rate (CFR) of meningococcal disease increased during the late 1980s and early 1990s in North Jutland County, Denmark. We examined the hypothesis that phenotypic markers of Neisseria meningitidis are predictors of septicaemia with or without meningitis, rapid disease progress and fatal outcome of meningococcal disease and we studied whether changes in IR and CFR over time might be related to emergence or spread of certain phenotypes. This follow-up study was based on a complete registration of 413 cases of meningococcal disease in North Jutland County during 1980-99. Phenotypic markers included serogroup, serotype and serosubtype. A complete phenotype was available for 315 cases (76 %); 100 (32 %) strains were phenotype B : 15 : P1.7,16 and 31 (10 %) were C : 2a : P1.2,5. Septicaemia without meningitis was less common in cases with B : 15 : P1.7,16 and C : 2a : P1.2,5 strains. No association was found between phenotype and rapid disease progress. The overall CFR was 12 %. An increased CFR was associated with phenotypes B : 15 : P1.7,16 [odds ratio (OR) 2.8, 95 % confidence interval (CI) 1.2-18.5] and C : 2a : P1.2,5 (OR 5.2, 95 % CI 1.6-16.4) when compared with other phenotypes. The prevalence of B : 15 : P1.7,16 strains increased gradually during the study period and the CFR increased from 8 % during 1980-89 to 19 % during 1990-99, although the CFR for other phenotypes also increased. The CFR for C : 2a : P1.2,5 remained high ( approximately 20 %), but the contribution of this phenotype to the overall CFR decreased during the study period. In conclusion, phenotypes B : 15 : P1.7,16 and C : 2a : P1.2,5 were predictors of an increased CFR. The high prevalence of phenotype B : 15 : P1.7,16 contributed to increased overall IR and CFR during 1990-99.

Performance of three microimmunofluorescence assays for detection of Chlamydia pneumoniae immunoglobulin M, G, and A antibodies.

The microimmunofluorescence (MIF) test is considered the "gold standard" for laboratory diagnosis of acute and chronic Chlamydia pneumoniae infection. The performance of a MIF test based on C. pneumoniae antigen from Washington Research Foundation (WRF) was compared with those of assays from Labsystems (LAB) and MRL Diagnostics (MRL) by investigation of sera from three groups of patients: group I, 83 sera from 28 patients with atypical pneumonia; group II, 37 sera from 16 patients with acute C. pneumoniae or Chlamydia psittaci respiratory tract infection confirmed by PCR or culture; group III, 100 sera from 100 persons enrolled in the Copenhagen City Heart Study. The accordance among the results of the WRF assay and the two commercial assays was excellent for the immunoglobulin M (IgM) antibody detection rate (98%). The accordance in detection rates for IgG and IgA antibodies in sera from patients with acute infections was acceptable (87 and 88%), and in sera from group III, it was excellent (95 and 97%). The determinations of endpoint titers were reproducible with <1 dilution step difference for all three methods, except that the mean IgM antibody titer found by the LAB assay was almost 2 dilution steps higher than that found by the other two methods. Although the three assays use different C. pneumoniae strains as antigens, the detection rates and IgG and IgA endpoint titers were similar. The difference in endpoint titers of IgM antibodies is of no major concern, as the diagnosis of acute C. pneumoniae infection rests on the presence of IgM antibodies, not on their level.