Proton pump inhibitors as a risk factor for norovirus infection.

Norovirus causes viral gastroenteritis, which is a major problem in health care. The disease causes death in elderly and seriously ill patients, and results in significant health costs each year. Proton pump inhibitors (PPIs) reduce gastric acidity, which is an important protection against microorganisms. We hypothesised that treatment with PPIs increases the risk of contracting norovirus infection. This has not previously been studied. The study was a retrospective case-control study, in which 192 hospitalised patients positive for norovirus in Örebro County, Sweden, were identified as cases. For each case, a hospitalised patient who did not have the infection was selected as a control, and matched with respect to ward, gender, admission date and age. Details of exposure, i.e. treatment with PPIs, were retrieved from the patient records. Odds ratio (OR) with confidence intervals (CIs) and P-values were calculated using McNemar's test. There was a significantly increased risk of norovirus infection in patients treated with PPIs compared with patients without PPI treatment (OR 1·73, 95% CI 1·07-2·81; P = 0·02). PPIs appear to be a risk factor for norovirus infection, and our results motivate future studies to further examine this association.

Clinical presentation of invasive disease caused by Neisseria meningitidis serogroup Y in Sweden, 1995 to 2012.

Over the period 1995-2012, the incidence of invasive meningococcal disease (IMD) caused by Neisseria meningitidis serogroup Y (NmY) increased significantly in Sweden. This is mainly due to the emergence of a predominant cluster named strain type YI subtype 1, belonging to the ST-23 clonal complex (cc). The aim of this study was to examine the clinical picture of patients with invasive disease caused by NmY and to analyse whether the predominant cluster exhibits certain clinical characteristics that might explain the increased incidence. In this retrospective observational study, the medical records available from patients with IMD caused by Nm serogroup Y in Sweden between 1995 and 2012 were systematically reviewed. Patient characteristics, in-hospital findings and outcome were studied and differences between the dominating cluster and other isolates were analysed. Medical records from 175 of 191 patients were retrieved. The median age was 62 years. The all-cause mortality within 30 days of admission was 9% (15/175) in the whole material; 4% (2/54) in the cohort with strain type YI subtype 1 and 11% (12/121) among patients with other isolates. Thirty-three per cent of the patients were diagnosed with meningitis, 19% with pneumonia, 10% with arthritis and 35% were found to have bacteraemia but no apparent organ manifestation. This survey included cases with an aggressive clinical course as well as cases with a relatively mild clinical presentation. There was a trend towards lower mortality and less-severe disease in the cohort with strain type YI subtype 1 compared with the group with other isolates.

Analytical evaluation of nine serological assays for diagnosis of syphilis.

BACKGROUND: The diagnosis of syphilis is most frequently dependent on antibody detection with serological assays. Assays for both treponemal and non-treponemal antibodies are needed to provide a sensitive and specific diagnosis. For decades, a first screening has been done with non-treponemal assays, followed by treponemal. However, in recent years, following laboratory automation, the reverse sequence screening algorithms have been developed, using a treponemal assay as the initial screening test. OBJECTIVE: To evaluate serological assays for treponemal and non-treponemal antibodies, to use in reverse algorithm screening of syphilis. MATERIAL AND METHODS: Six treponemal assays (one IgM-specific assay), two non-treponemal assays and one novel dual point-of-care (POC) assay for serological diagnosis of syphilis were evaluated. Serum samples from Guinea-Bissau and Sweden were examined, as well as two performance panels and samples from blood donors. Sensitivity and specificity were calculated for each assay, using different assays as gold standard test. RESULTS: The Macro-Vue RPR Card test was the most sensitive non-treponemal test and the TrepSure Anti-Treponema EIA Screen and the SeroDia TP-PA were the most sensitive and specific treponemal assays. Among the automated assays, both the Liaison Treponema Screen and Architect Syphilis TP showed high sensitivity, however, the former had clearly higher specificity. CONCLUSIONS: In resourced settings, where the reverse sequence algorithm is preferred for screening, an automated treponemal immunoassay for initial screening subsequently followed by the TrepSure test or TP-PA assay as a second treponemal assay appear highly effective. Finally, a quantitative highly sensitive non-treponemal assay, e.g. the Macro-Vue RPR Card test, could then be used as a supplementary test to evaluate activity of the syphilis infection.

Multiple human-to-human transmission from a severe case of psittacosis, Sweden, January-February 2013.

Proven transmission of Chlamydia psittaci between humans has been described on only one occasion previously. We describe an outbreak which occurred in Sweden in early 2013, where the epidemiological and serological investigation suggests that one patient, severely ill with psittacosis after exposure to wild bird droppings, transmitted the disease to ten others: Two family members, one hospital roommate and seven hospital caregivers. Three cases also provided respiratory samples that could be analysed by PCR. All the obtained C. psittaci sequences were indistinguishable and clustered within genotype A. The finding has implications for the management of severely ill patients with atypical pneumonia, because these patients may be more contagious than was previously thought. In order to prevent nosocomial person-to-person transmission of C. psittaci, stricter hygiene measures may need to be applied.

Surveillance of invasive Neisseria meningitidis with a serogroup Y update, Sweden 2010 to 2012.

An increase of invasive meningococcal disease caused by Neisseria meningitidis serogroup Y has been noted in Sweden since 2005, and to a lower extent throughout Europe. The present study describes the epidemiology of invasive N. meningitidis isolates in Sweden in the period between 2010 and 2012, with a focus on serogroup Y. We also aimed to find an optimal molecular typing scheme for both surveillance and outbreak investigations. All invasive N. meningitidis isolates in Sweden during the study period (n=208) were genetically characterised. Serogroup Y predominated with 22/57, 31/61 and 44/90 of all invasive isolates (incidence 0.23, 0.33 and 0.46 per 100,000 population) in 2010, 2011 and 2012 respectively. In each of these years, 15/22, 22/31 and 19/44 of serogroup Y isolates were genetically clonal (Y: P1.5­2,10­1,36­2: F4­1: ST-23(cc23), 'porB allele 3­36, fHbp allele 25 and penA allele 22). Our findings further support those of others that currently recommended FetA typing could be replaced by FHbp. Moreover, in line with a previous study that we conducted, the current results indicate that highly variable multilocus variable-number tandem repeat analysis (HV-MLVA) can be used as a first-hand rapid method for small outbreak investigations.

Four treatment failures of pharyngeal gonorrhoea with ceftriaxone (500 mg) or cefotaxime (500 mg), Sweden, 2013 and 2014.

We describe four cases in Sweden of verified treatment failures of pharyngeal gonorrhoea with ceftriaxone (500 mg; n=3) or cefotaxime (500 mg; n=1) monotherapy. All the ceftriaxone treatment failures were caused by the internationally spreading multidrug-resistant gonococcal NG-MAST genogroup 1407 clone. Increased awareness of treatment failures is crucial particularly when antimicrobial monotherapy is used. Frequent test of cure and appropriate verification/falsification of suspected treatment failures, as well as implementation of recommended dual antimicrobial therapy are imperative.

Evaluation of a commercial multiplex PCR test (SeptiFast) in the etiological diagnosis of community-onset bloodstream infections.

The commercial polymerase chain reaction (PCR) test, SeptiFast, is designed to identify the DNA of individual bacterial and fungal pathogens in whole blood. We aimed to evaluate the usefulness of the test for the detection of community-onset bloodstream infections. We prospectively included adult patients who were subjected to blood culture (BC) at an infectious diseases department. For the evaluation, one BC/PCR set (two BC bottles and one PCR tube) per patient was used. When several sets were obtained and analyzed, the first set with any positive result was evaluated. Among 1,093 consecutively included patients, BC was positive in 138 and PCR was positive in 107. Fifty positive PCR results were supported by BC in the same BC/PCR set, ten were supported by other cultures, and, additionally, ten were supported by the clinical presentation. Compared with BC, PCR showed specificities and negative predictive values of >97% for all detectable pathogens. The following sensitivities and positive predictive values (PPVs) were noted: Staphylococcus aureus, 67% and 43%; Streptococcus pneumoniae, 12% and 67%; other Streptococcus species, 43% and 77%; Escherichia coli, 53% and 56%; and Klebsiella species, 43% and 23%. If support from other cultures and the clinical presentation were included in the reference standard, the PPVs for the detection of these bacteria were 57%, 100%, 92%, 75%, and 69%, respectively. Although the specificities were high, the low sensitivities and suboptimal PPVs noted in the present study discourage routine use of the test in its present form for the detection of community-onset bloodstream infections.

A case of diphtheria in Sweden, October 2011.

In October 2011, a child who had arrived in Sweden from Somalia presented with atypical tonsillitis, was treated with penicillin and the symptoms resolved. A throat swab was positive for toxigenic Corynebacterium diphtheriae. The child's family were then vaccinated with diphtheria, tetanus and pertussis vaccine and screened for C. diphtheriae. No secondary cases were found. A high level of adherence to childhood vaccination programmes is an effective way to protect populations against diphtheria.

Genetic characterisation of the emerging invasive Neisseria meningitidis serogroup Y in Sweden, 2000 to 2010.

Neisseria meningitidis serogroups B and C have been responsible for the majority of invasive meningococcal disease in Europe. Recently, an increase of N. meningitidis disease due to serogroup Y has been noted in Sweden (in 2010, the proportion was 39%, with an incidence of 0.23 per 100,000 population), as well as in other northern European countries. We aimed to investigate the clonal pattern of the emerging serogroup Y in Sweden during 2000 to 2010. The serogroup Y isolates identified during this time (n=85) were characterised by multilocus sequence typing and sequencing of the fetA, fHbp, penA, porA and porB genes. The most frequent clone (comprising 28 isolates) with identical allele combinations of the investigated genes, was partly responsible for the observed increased number of N. meningitidis serogroup Y isolates. It was sulfadiazine resistant, with genosubtype P1.5-2,10-1,36-2, sequence type 23, clonal complex 23, porB allele 3-36, fetA allele F4-1, fHbp allele 25 and penA allele 22. The first case with disease due to this clone was identified in 2002: there was a further case in 2004, six during 2006 to 2007, eight during 2008 to 2009, with a peak of 12 cases in 2010. An unusual increase of invasive disease in young adults (aged 20­29 years) caused by this clone was shown, but no increase in mortality rate was observed.

Sampling for Chlamydia trachomatis infection - a comparison of vaginal, first-catch urine, combined vaginal and first-catch urine and endocervical sampling.

The aim of the study was to evaluate the sensitivity of patients' self-sampled vaginal specimens, first-catch urine (FCU), combined vaginal/FCU specimens and endocervical specimens for detecting chlamydial infection in women. Women attending sexually transmitted disease clinics, youth clinics and a women's health clinic were enrolled. They self-collected a vaginal specimen with two swabs, which were placed into a sterile tube and into a tube containing a buffer medium, respectively. An FCU sample was collected and aliquoted into both an empty tube and the tube containing the vaginal swab. A clinician collected an endocervical swab. The samples were sent to laboratories for analysis using polymerase chain reaction testing and strand displacement amplification testing, respectively. The sensitivities calculated in all 171 Chlamydia trachomatis-infected women were equal for endocervical specimens (97.1%), vaginal specimens (96.5%) and combined vaginal/FCU specimens (95.3%), whereas the sensitivity for FCU was significantly lower (87.7%). The sensitivity of vaginal specimens for the detection of C. trachomatis is as high as that of combined vaginal/FCU specimens.

Evaluation of the new COBAS TaqMan CT test v2.0 and impact on the proportion of new variant Chlamydia trachomatis by the introduction of diagnostics detecting new variant C trachomatis in Orebro county, Sweden.

BACKGROUND: The new variant of Chlamydia trachomatis (nvCT), discovered in Sweden in 2006, contains a 377-bp cryptic plasmid deletion, which includes the targets for the COBAS Amplicor/TaqMan C trachomatis/Neisseria gonorrhoea and Abbott m2000rt C trachomatis/N gonorrhoea tests. OBJECTIVES: To evaluate the new real-time COBAS TaqMan CT test v2.0 (CTM CT v2.0) for C trachomatis diagnostics and to investigate whether the proportion of nvCT was affected by the introduction of genetic diagnostics detecting nvCT (LightMix 480HT) in Orebro county, Sweden. METHODS: CTM CT v2.0 compared with LightMix 480 HT PCR for the diagnosis of C trachomatis was evaluated. Discrepant samples were analysed using BD ProbeTec ET and Abbott m2000rt RealTime CT II. All previously LightMix and cell culture-positive samples were analysed using an nvCT-specific PCR. RESULTS: The sensitivity, specificity, negative predictive value and positive predictive value of CTM CT v2.0 for examined samples (n = 1058) was 100%, 99.8%, 100% and 98.2%, respectively. Of 11,577 consecutive PCR samples, 9.4% (n = 1084) were positive and 34.3% (n = 372) of these were nvCT. Of 2306 consecutive culture samples, 5.0% (n = 116) were C trachomatis positive and 38.8% (n = 45) of these were nvCT. CONCLUSIONS: CTM CT v2.0 is a sensitive and specific method for C trachomatis detection. Studies including larger numbers of symptomatic and asymptomatic patients as well as genital and extragenital samples, and in comparison with other internationally validated and, ideally, US Food and Drug Administration-approved C trachomatis nucleic acid amplification tests are imperative. The proportion of nvCT remains high in Orebro county, Sweden, despite the introduction of genetic diagnostics to detect the mutant.

Positive reinforcement training in rhesus macaques-training progress as a result of training frequency.

Positive reinforcement training (PRT) efficiency was examined as a function of training frequency in 33 pair- or triple-housed female rhesus macaques. The animals were trained three times a week, once a day or twice a day, using PRT and a clicker as a secondary reinforcer. All animals were trained on 30 sessions, with an average of 5 min per training session per animal. The behaviors, trained in succession, were Targeting (reliably touching and following a Target); Collaborating (dominant animals allowing subordinates to train while stationing); Box-training (accepting being enclosed in a small compartment while responding to Target training) and initial Injection training.Fulfilled criteria for Targeting were obtained in 32/33 animals in a median of nine training sessions. Collaboration was obtained in 27/33 animals in a median of 15 training sessions. However, only four animals completed Box-training during the 30 training sessions and started Injection training. When comparing training success in terms of number of training sessions, training twice a day was less efficient than the other two treatments. In terms of daily progress, our results suggest that from a management perspective, daily training is more conducive to quick training success than thrice weekly training. In addition, in this study no further advantages could be gained from training twice a day.

Neisseria gonorrhoeae population in Arkhangelsk, Russia: phenotypic and genotypic heterogeneity.

Reliable data concerning the incidence and phenotypic and genotypic characteristics of the Neisseria gonorrhoeae population in many eastern European countries are lacking. Clinically significant N. gonorrhoeae isolates (n = 76) from 76 consecutive patients in Arkhangelsk, Russia were characterised by antimicrobial susceptibility testing, serovar determination, porB gene sequencing and N. gonorrhoeae multi-antigen sequence typing (NG-MAST). The isolates were assigned to 12 different serovars, displayed 35 divergent porB sequences, and belonged to 40 different sequence types (STs). All the serovars, but only seven of the STs, had been identified previously in other countries. Twelve ST clusters of between two and 14 isolates were identified, which indicated that many multiple transmission networks exist in Arkhangelsk. The high number of unique STs (n = 28) may be a consequence of sub-optimal diagnostic procedures, ineffective partner tracing, local emergence of new STs, import of strains via sexual tourists, or foreign travel. The N. gonorrhoeae population circulating in Arkhangelsk was highly diverse and differed from the N. gonorrhoeae populations disseminated in some western European countries. Thorough knowledge concerning the incidence of gonorrhoea, antibiotic susceptibility and other phenotypic and genotypic characteristics of the N. gonorrhoeae strains circulating in eastern Europe is crucial.

Experiences with the new genetic variant of Chlamydia trachomatis in Orebro county, Sweden - proportion, characteristics and effective diagnostic solution in an emergent situation.

A Chlamydia trachomatis variant that contains a 377 bp deletion in the cryptic plasmid was recently reported in Sweden. This deletion includes the targets for Cobas Amplicor, Cobas TaqMan48, and Abbott m2000. We examined the proportion and characteristics of this variant in Orebro county, Sweden and developed an effective diagnostic solution. In total, 2,401 consecutive C. trachomatis culture samples and 536 PCR samples from symptomatic and asymptomatic patients and screened females were included. Culture, Cobas Amplicor, and LightMix 480HT were used for diagnosis. A mutant-specific PCR, plasmid sequencing, omp1 sequencing and multilocus sequence typing (MLST) were used to identify and characterise mutants. In total, 162 (6.7%) of the cultured samples were positive for C. trachomatis. However, 61 (38%) of those were negative when using Cobas Amplicor, and 60 of these were subsequently confirmed as the new variant. 13 of these mutant isolates were further characterised genetically, and all were of identical genotype E and the unique MLST sequence type: 21, 19, 1, 2, 1. Of all culture-positive samples, 161 of 162 were positive in the LightMix 480HT assay. The single negative sample was only weakly positive in culture, and negative in all PCRs. Of the 536 PCR samples, 37 were positive in both Cobas Amplicor and LightMix 480HT, 13 were only positive in LightMix 480HT (mutants), and two were only positive in Cobas Amplicor. Mutated C. trachomatis were prevalent in Orebro county in the period from October 2006 to February 2007, and it appeared to be a single clone. LightMix 480HT seemed sensitive, specific, and enabled high throughput diagnostics. However, rare low positive samples may be false-negative. Frequent surveillance and evaluations of diagnostic methods worldwide are crucial.

Optimization of polymerase chain reaction for detection of HIV type 2 DNA.

The aim of this study was to increase the sensitivity of an earlier version of an HIV-2 nested PCR assay based on primers in the gag, pol, LTR, and env regions. The assay was first optimized with regard to concentrations of dNTP, MgCl2, and primers, using a method that allowed optimization of all three parameters in only two test runs. We then designed and optimized new primer sets in the LTR, gag, and gag/pol regions that were based on more isolates than were the former (old) primer sets. Samples from 57 HIV-2 antibody-positive individuals were tested with the four old primer sets as well as with the three new primer sets. Five primer sets from this run (new gag, new gag/pol, old LTR, old env, and new LTR) were then tested with 35 more samples, giving a total number of 92 tested samples from HIV-2-infected individuals. At initial testing of the 92 samples a combination of primer sets from two different regions yielded a sensitivity ranging from 93.5 to 98.9%. After repeated testing the sensitivity ranged from 96.7 to 100% for the different primer combinations. The specificity was 100% for all primer sets except old LTR, which had a specificity of 97%. In conclusion, it is possible to create a more sensitive PCR assay by optimizing the different PCR parameters as well as by including primer sets based on more isolates.

A reference procedure to study chemiluminescence induced in polymorphonuclear leukocytes by Neisseria meningitidis.

Luminol-enhanced chemiluminescence (CL) was used to study the ability of various strains of Neisseria meningitidis (MC) to induce oxidative metabolism of polymorphonuclear leukocytes (PMNL); an indirect measure of phagocytic activity. To circumvent variations related to different PMNL donors, a MC serogroup X strain was used as a control for indexing the CL responses induced by other MC strains. This procedure, with pooled serum from healthy blood donors to standardize opsonising conditions, gave reproducible and comparable results, irrespective of PMNL donors. Under these conditions, there was a highly significant difference between pathogenic and non-pathogenic MC strains as regards their ability to induce CL responses (p less than 0.001). The results indicated that the differences were due partly to opsonizing antibodies, partly to other differences related to pathogenicity of tested MC strains. These differences in leukocyte/MC interaction were also confirmed by phagocytic-killing experiments. The index procedure of CL measurements may be a suitable method to study the appearance of natural immunity to MC disease, as well as the pathogenicity of particular MC strains.

The effects of live Neisseria meningitidis and tumour necrosis factor-alpha on neutrophil oxidative burst and beta2-integrin expression.

The effects of human recombinant tumour necrosis factor-alpha (TNF-alpha) on neutrophil (PMNL) oxidative burst and on CD11b/CD18 and CD14 expression after stimulation with pathogenic or nonpathogenic Neisseria meningitidis were studied using chemiluminescence and flow cytometry. PMNL oxidative burst increased more when stimulated with the apathogenic 29E strain than with the pathogenic B strain both when studied by chemiluminescence and by flow cytometry. When TNF-alpha was added to whole blood or PMNL together with bacteria a significant increase in the oxidative burst was seen for the B strain only. When whole blood was preincubated for 30 min with TNF-alpha the increase in oxidative burst was significant for both meningococcal strains. TNF-alpha caused a significant increase in PMNL CD 11b/CD18 expression after 30 min of incubation at 37 degrees C. TNF-alpha added simultaneously with the bacteria induced a significant increase in PMNL CD11b/CD18 in both strains. Incubation with the B strain alone caused a low but significant increase in CD11b/CD18 expression, but the addition of TNF-alpha increased this expression to the same high level as incubation with TNF-alpha alone or the 29E strain alone. Only TNF-alpha and the 29E strain caused significant increases in CD14 expression. In conclusion, human PMNLs react differentially when stimulated with pathogenic and nonpathogenic N. meningitidis and the activating effect of TNF-alpha is variable depending on the bacteria involved.

A comparison between Bactec aerobic resin and hypertonic blood culture media.

The presence of antimicrobial agents in patients' blood is thought to represent an important source of false-negative blood cultures. This has led to the incorporation of agents with inhibitory effects on antimicrobial drugs into culture medium. In the present study, Bactec aerobic resin-containing blood culture medium was compared with Bactec hypertonic blood culture medium. 504 patients receiving cytostatic and/or antibiotic treatment were studied. Sensitivity calculations on detection of bacteremia in these patients gave 0.91 for the resin medium and 0.79 for the hypertonic blood culture system and showed a significant difference (p = 0.016). In addition, the resin-containing system more rapidly detected positive cultures than the hypertonic system.

Early development in healthy children of serum opsonins against nonpathogenic Neisseria meningitidis.

In an earlier study, with the use of chemiluminescence (CL) and phagocytic killing, we could show that in the presence of serum from healthy adults polymorphonuclear leukocytes (PMNL) efficiently handle nonpathogenic Neisseria meningitidis strains, in sharp contrast to those associated with clinical disease. The major part of this difference was dependent on serum factors. In the present study 84 serum samples from children 1-3, 4-6, 7-9, and 10-14 years old were studied by the CL technique according to their ability to opsonize meningococci. There was a highly significant difference (p less than 0.001) in all four age groups when the CL indexes obtained with the pathogenic meningococci of the serogroups A, B and C were compared with those of the nonpathogenic menigococci: serogroup 29E and nongroupable meningococci. These findings imply that the ability to opsonize so-called nonpathogenic meningococci is developed early in life and may explain why they are only occasionally able to cause disease.

Mobiluncus species in bacterial vaginosis: aspects of pathogenesis.

Mobiluncus is an anaerobic motile rod associated with bacterial vaginosis. In this work, luminol-enhanced chemiluminescence was used to study the ability of Mobiluncus spp. from the vaginas of women with bacterial vaginosis to induce, in the presence of normal adult serum, oxidative metabolism of polymorphonuclear leukocytes, which is an indirect measure of phagocytic activity. M. curtisii induced a significantly (p less than 0.05) lower response than M. mulieris, which indicates that M. curtisii escapes phagocytosis more easily. Indirect immunofluorescence assays showed IgG antibodies to M. curtisii at significantly (p less than 0.01) higher titres than to M. mulieris in women with bacterial vaginosis. The titres were higher in patients with bacterial vaginosis than in women without vaginosis and healthy men. No antibodies to Mobiluncus spp. of secretory IgA type were found in vaginal washings. These results indicate that M. curtisii is a more virulent species than M. mulieris, and agree with reports of M. curtisii found in postoperative and extragenital infections.