Description and validation of a new automated surveillance system for Clostridium difficile in Denmark.

The surveillance of Clostridium difficile (CD) in Denmark consists of laboratory based data from Departments of Clinical Microbiology (DCMs) sent to the National Registry of Enteric Pathogens (NREP). We validated a new surveillance system for CD based on the Danish Microbiology Database (MiBa). MiBa automatically collects microbiological test results from all Danish DCMs. We built an algorithm to identify positive test results for CD recorded in MiBa. A CD case was defined as a person with a positive culture for CD or PCR detection of toxin A and/or B and/or binary toxin. We compared CD cases identified through the MiBa-based surveillance with those reported to NREP and locally in five DCMs representing different Danish regions. During 2010-2014, NREP reported 13 896 CD cases, and the MiBa-based surveillance 21 252 CD cases. There was a 99·9% concordance between the local datasets and the MiBa-based surveillance. Surveillance based on MiBa was superior to the current surveillance system, and the findings show that the number of CD cases in Denmark hitherto has been under-reported. There were only minor differences between local data and the MiBa-based surveillance, showing the completeness and validity of CD data in MiBa. This nationwide electronic system can greatly strengthen surveillance and research in various applications.

Hand hygiene compliance in nursing home wards: the effect of increased accessibility of alcohol-based hand rub.

BACKGROUND: Elderly nursing home residents are vulnerable to infection from micro-organisms. Hand hygiene is considered one of the most important measures to prevent transmission. AIM: To determine the effect of increased accessibility to alcohol-based hand rub (ABHR) in nursing home wards by monitoring hand hygiene compliance (HHC) among healthcare workers (HCWs). METHODS: An 11-month intervention study was conducted in a Danish six-ward nursing home. Data were collected using an automatic hand hygiene monitoring system (AHHMS). After a baseline period, one extra ABHR dispenser was placed in each of the 150 apartments. Baseline HHC was compared with the HHC during an immediate intervention period and a long-term intervention period. FINDINGS: A total of 159 HCWs were included. The AHHMS registered 341,078 hand hygiene opportunities. Overall baseline HHC was 31% (95% confidence interval: 30-32). A significant +18% absolute immediate effect (first five months) (95% CI: 17-19; P < 0.0001) and +13 percentage points (95% CI: 11-14; P < 0.0001) long-term effect (another four months) were recorded. HCWs working day shifts and short-term employees had a higher baseline HHC than HCWs working evening/night shifts. However, HCWs working night shifts achieved the greatest long-term effect with a mean +27 percentage point difference (P < 0.0001). CONCLUSION: Placing an additional ABHR dispenser strategically within staff workflow significantly increased HHC among HCWs, demonstrating a noteworthy effect. The study is the first to report the effect on nursing home dispenser accessibility as a single intervention and to show a significant unmet potential.

The role of viruses in the pathogenesis of peritonsillar abscess.

Peritonsillar abscess (PTA) is the most frequent complication of acute tonsillitis and a prevalent cause for acute admission to otorhinolaryngology departments. Our aim was to examine the role of viruses in the pathogenesis of PTA, as this has not previously been considered. We examined both palatine tonsils from 25 patients undergoing acute tonsillectomy for PTA, using PCR-based assays for herpes simplex virus-1 and -2 (HSV-1 and -2), adenovirus, Epstein-Barr virus (EBV), influenza A and B, and respiratory syncytial virus (RSV) A and B. We similarly examined tonsils from 55 patients undergoing elective tonsillectomy due to chronic tonsillar conditions. These patients served as a control group, as they did not have a clinically apparent infection at the time of surgery. Only HSV-1 (5/80, 6.3%), adenovirus (11/80, 13.8%), and EBV (71/80, 88.8%) were detected in our study population. There was no statistically significant difference in the frequency of these viruses across different diagnostic groups. Quantification of EBV load demonstrated no differences between the PTA and the elective tonsillectomy group, nor between the abscessed and non-abscessed tonsil of PTA patients. In summary, our data do not support a significant role for the examined viruses in the pathogenesis of PTA.

Increased incidence of Mycoplasma pneumoniae infections detected by laboratory-based surveillance in Denmark in 2010.

In Denmark recurrent epidemics of Mycoplasma pneumoniae infections have been described since the 1950s at intervals of approximately four to six years. The latest epidemic occurred in 2004/05 followed by two years of high incidence and more than three years of low incidence. Due to a recent increase in diagnosed cases since late summer 2010, we conducted a survey of positive M. pneumoniae PCR tests performed by clinical microbiology departments in Denmark, which indicated that a new epidemic may be underway.

Detection of meticillin-resistant Staphylococcus aureus and carbapenemase-producing Enterobacteriaceae in Danish emergency departments - evaluation of national screening guidelines.

BACKGROUND: Multi-resistant bacteria (MRB) are an emerging problem. Early identification of patients colonized with MRB is mandatory to avoid in-hospital transmission and to target antibiotic treatment. Since most patients pass through specialized emergency departments (EDs), these departments are crucial in early identification. The Danish National Board of Health (DNBH) has developed exposure-based targeted screening tools to identify and isolate carriers of meticillin-resistant Staphylococcus aureus (MRSA) and carbapenemase-producing Enterobacteriaceae (CPE). AIM: To assess the national screening tools for detection of MRSA and CPE carriage in a cohort of acute patients. The objectives were to investigate: (i) if the colonized patients were detected; and (ii) if the colonized patients were isolated. METHODS: This was a multi-centre cross-sectional survey of adults visiting EDs. The patients answered the DNBH questions, and swabs were taken from the nose, throat and rectum. The collected samples were examined for MRSA and CPE. Screening performances were calculated. FINDINGS: Of the 5117 included patients, 16 were colonized with MRSA and four were colonized with CPE. The MRSA screening tool had sensitivity of 50% [95% confidence interval (CI) 25-75%] for carrier detection and 25% (95% CI 7-52%) for carrier isolation. The CPE screening tool had sensitivity of 25% (95% CI 1-81%) and none of the CPE carriers were isolated. CONCLUSION: The national screening tools were of limited use as the majority of MRSA and CPE carriers passed unidentified through the EDs, and many patients were isolated unnecessarily.

Early and late markers for the detection of early-onset neonatal sepsis.

INTRODUCTION: In this study we tested how a combination of early and late paraclinic markers could predict early onset neonatal sepsis (EONS). METHODOLOGY: The first 24 hours after the suspicion of EONS, we measured interleukine (IL)-6, IL-8, IL-10, IL-18, tumor necrosis factor-alpha (TNF-alpha), interferon gamma (INF-gamma), procalcitonin (PCT) and C-reactive protein (CRP) at 8-hour intervals on 123 neonates clinically suspected for EONS. The neonates were divided into two groups. The sepsis group: 1A with blood culture verified bacteraemia and 1B strongly suspected sepsis (29 patients). The no sepsis group: 2A treated with antibiotics (37 patients) and 2B not treated with antibiotics (57 patients). RESULTS: Combined evaluation of each of the early markers with PCT > 25 ng/ml for prediction of EONS at time 0, gave the following sensitivities and specificities: IL-6 > 250 pg/ml: 71% and 88%; IL-8 > 900 pg/ml: 50% and 88%; IL-10 > 40 pg/ml: 43% and 87%; and immature/total (I/T) ratio > 0.35: 59% and 88%. The results of IL-18, TNF-alpha and IFN-gamma did not predict EONS. CONCLUSION: IL-6 combined with PCT values is a fair way to evaluate EONS at the time of suspicion of infection. The "old" early marker, I/T ratio, is almost as efficient as IL-6. By combining an early and a late marker it may be possible to reduce the diagnostic "non-conclusive" period of paraclinic values.

Automated surveillance system for hospital-acquired urinary tract infections in Denmark.

BACKGROUND: The Danish Hospital-Acquired Infections Database (HAIBA) is an automated surveillance system using hospital administrative, microbiological, and antibiotic medication data. AIM: To define and evaluate the case definition for hospital-acquired urinary tract infection (HA-UTI) and to describe surveillance data from 2010 to 2014. METHODS: The HA-UTI algorithm defined a laboratory-diagnosed UTI as a urine culture positive for no more than two micro-organisms with at least one at ≥10(4)cfu/mL, and a probable UTI as a negative urine culture and a relevant diagnosis code or antibiotic treatment. UTI was considered hospital-acquired if a urine sample was collected ≥48h after admission and <48h post discharge. Incidence of HA-UTI was calculated per 10,000 risk-days. For validation, prevalence was calculated for each day and compared to point prevalence survey (PPS) data. FINDINGS: HAIBA detected a national incidence rate of 42.2 laboratory-diagnosed HA-UTI per 10,000 risk-days with an increasing trend. Compared to PPS the laboratory-diagnosed HA-UTI algorithm had a sensitivity of 50.0% (26/52) and a specificity of 94.2% (1842/1955). There were several reasons for discrepancies between HAIBA and PPS, including laboratory results being unavailable at the time of the survey, the results considered clinically irrelevant by the surveyor due to an indwelling urinary catheter or lack of clinical signs of infection, and UTIs being considered HA-UTI in PPS even though the first sample was taken within 48h of admission. CONCLUSION: The HAIBA algorithm was found to give valid and valuable information and has, among others, the advantages of covering the whole population and allowing continuous standardized monitoring of HA-UTI.

Acyclovir prophylaxis and fever during remission-induction therapy of patients with acute myeloid leukemia: a randomized, double-blind, placebo-controlled trial.

PURPOSE: A randomized, double-blind, placebo-controlled trial was performed to estimate the preventive effect of the antiherpetic drug acyclovir on fever, incidence of bacteremia, use of antibiotics, and presentation of infections in patients with acute myeloid leukemia (AML). PATIENTS AND METHODS: Ninety herpes simplex virus (HSV)-seropositive patients aged 18 to 84 years were included. Forty-five patients received acyclovir (800 mg by mouth daily) and 45 placebo. The patients were examined daily for 28 days from the initiation of remission-induction chemotherapy. RESULTS: Fever developed in all patients in both groups. Acyclovir prophylaxis postponed the development of an oral temperature > or = 38.0 degrees C by 3 days (95% confidence interval [CI], 1 to 4 days; P = .03) and the initiation of antibacterial treatment by 3 days (95% CI, 1 to 5 days; P = .008). The duration of fever, use of antibacterial treatment, incidence of bacteremia, and need for systemic antifungal therapy were not affected by acyclovir prophylaxis. At fever development, acyclovir prophylaxis affected the incidence and localization pattern of oral ulcers. Thus, in the acyclovir group, the number of nonfungal oral infections was reduced (relative risk, 0.45 [95% CI, 0.24 to 0.85]) and mainly located on the soft palate (relative risk, 2.49 [95% CI, 1.19 to 5.22]). CONCLUSION: Acyclovir prophylaxis has an impact on fever development, but not on the duration of fever or the need for antibiotics. It does not reduce the incidence of bacteremia, but the presentation of acute oral infections is changed.

Effect of IL-4 and IL-13 on IFN-gamma-induced production of nitric oxide in mouse macrophages infected with herpes simplex virus type 2.

Interleukin (IL)-4 and IL-13 share a wide range of activities. Prominent among these is the ability to antagonize many interferon (IFN)-gamma-induced activities. Here we demonstrate that IL-4 and IL-13 totally abrogate IFN-gamma-induced nitric oxide (NO) production and inducible nitric oxide synthase (iNOS) mRNA and protein synthesis in a murine macrophage cell line. IFN-gamma-treated cells infected with herpes simplex virus type 2 (HSV-2) or costimulated with tumor necrosis factor (TNF)-alpha showed an enhanced reactivity, which was only partially reduced by IL-4/13. The results indicate that IL-4 and IL-13 function by intervening with a step prior to iNOS transcription by antagonizing IFN-gamma-induced signal(s) without counteracting synergistic virus- or TNF-alpha-induced signals. The beneficial effect of a sustained NO production in foci of virus infection is suggested.

Inhibition of NO production in macrophages by IL-13 is counteracted by Herpes simplex virus infection through tumor necrosis factor-alpha-induced activation of NK-kappa B.

Interleukin (IL)-13 is known to antagonize many interferon (IFN)-gamma-activated functions in macrophages and among these, nitric oxide (NO) production. We have previously shown that this function of IL-13 is reduced in Herpes simplex virus type 2 (HSV-2)-infected macrophages. In the present study we show that IL-13 and IFN-gamma are indeed produced during infection of BALB/c mice with HSV-2. The lack of inhibitory function of IL-13 in infected macrophages, which was not overcome even at very high concentrations of IL-13, was not due to impaired IL-13 signalling, since virus infection did not affect IL-13-mediated activation of STAT6 (signal transducer and activator of transcription 6). Neutralizing tumour necrosis factor (TNF)-alpha antibodies, however, largely restored the effect of IL-13 on NO production in virus-infected macrophages. The same was observed after treatment of the cells with inhibitors of nuclear factor (NF)-kappa B activation, known to be involved in enhancement of IFN-gamma-induced NO production. Even though IL-13 reduced TNF-alpha secretion by 50%, this did not impair NF-kappa B activation in IFN-gamma-treated cells infected with HSV-2. The results indicate that TNF-alpha, secreted by virus-infected macrophages, activates NF-kappa B which impairs the IL-13-mediated inhibition of inducible NO synthase (iNOS) expression. This could imply that a sustained NO production would be focused to sites of active virus replication.

Interferon (IFN)-gamma and Herpes simplex virus/tumor necrosis factor-alpha synergistically induce nitric oxide synthase 2 in macrophages through cooperative action of nuclear factor-kappa B and IFN regulatory factor-1.

The radical nitric oxide (NO) constitutes an important part of the innate immune response to many viruses, and among these notably Herpes simplex virus (HSV). We have previously shown that HSV/tumor necrosis factor-alpha (TNF-alpha) and IFN-gamma synergistically induce NO production in macrophages, and here we have investigated the molecular mechanism underlying this phenomenon. The enhancement of NO production was regulated at the level of NO synthase 2 (NOS2, iNOS) transcription. The ISRE element of the NOS2 promoter, which binds IFN regulatory factor (IRF)-1, was essential both for full responsiveness to IFN-gamma and the synergistic response. The GAS motif, binding signal transducer and activator of transcription 1 (STAT1), did not contribute to the cross-talk with virus/TNF-induced signals, but was necessary for full responsiveness to IFN-gamma. The distal binding site for nuclear factor (NF)-kappa B was important for the cooperative response, while the proximal kappa B site was not involved in the cooperative promoter activation but played a role in full promoter inducibility. By ectopic expression of IRF-1 and NF-kappa B (p65), we found that these factors synergistically induce NO accumulation. Together, our results show that binding of IRF-1 and NF-kappa B to their respective sites in the distal domain of the NOS2 promoter, creates a potent trans-activating complex with the ability to induce NOS2 transcription synergistically in response to simultaneous HSV-2/TNF-alpha and IFN-gamma treatment.

Influence of mercuric chloride on resistance to generalized infection with herpes simplex virus type 2 in mice.

The effect of mercuric chloride on resistance to generalized infection with herpes simplex virus type 2 (HSV-2) in mice was studied. The severity of the infection was evaluated by the amount of infectious virus in the liver. Mercury at a single dose of 20 micrograms aggravated the infection, and neither increasing the single dose to 80 micrograms nor giving repeated doses of 20 micrograms further intensified the infection. Examination of the course of infection after mercury exposure revealed an increased virus replication and dissemination during the first days of the infection, indicating that the early, nonspecific defence mechanisms were affected. Virus clearance and elimination, which is mediated by specific immunity, seemed not to be influenced. Examination of cells from the peritoneal cavity and of livers from virus-infected mice showed that mercury detectable by autometallography was exclusively found in mature peritoneal macrophages and in Kupffer cells of the liver. Inflammatory cells, recruited to the peritoneal cavity or infiltrating the infectious foci of the liver, did not show any mercury deposits. Attempts to demonstrate an effect in vivo of mercury on potential antiviral macrophage functions like interferon-alpha/beta (IFN-alpha/beta) and tumour necrosis factor-alpha (TNF-alpha) secretion and oxidative burst capacity were not successful, possibly because recruited, inflammatory cells, which have not been exposed to the high mercury concentrations at the site of injection, take over these functions of intoxicated macrophages.

Effect of mercuric chloride on macrophage-mediated resistance mechanisms against infection with herpes simplex virus type 2.

Macrophages play an important role in the early, nonspecific resistance to infection with herpes simplex virus. Mercuric chloride (HgCl2) accumulates in macrophages and has in certain concentrations a marked influence on the functional capacity of these cells. Therefore the influence of HgCl2 on resistance to generalized infection with herpes simplex virus type 2 (HSV-2) in mice and its effect on the HSV-2-induced activation of macrophages in vitro was examined. Mice injected intraperitoneally with HgCl2 24 h before infection with HSV-2 had more than 100 times higher virus titres in the liver 4 days after infection than mice not receiving any mercury. HgCl2 exerted a toxic effect on macrophages in vitro, which was especially pronounced during their adherence. Macrophages infected with HSV-2 were activated for an enhanced respiratory burst. This activation was abolished by treatment of the cells for 24 h with relatively low concentrations of HgCl2, resulting in macrophages with a potential to react with a respiratory burst comparable to that of uninfected cells. The HSV-2-induced activation of macrophages is mediated through the production and synergistic interaction of interferon-alpha/beta and tumour necrosis factor-alpha in an autocrine manner. The ability of these cytokines to activate macrophages and to interact synergistically was not affected by mercury. However the production by macrophages of both cytokines during the HSV-2 infection, but especially interferon-alpha/beta, which is essential for the activation, was reduced at low concentrations of HgCl2. Collectively these data indicate that mercury, by interfering with the early macrophage-production of cytokines, disables the early control of virus replication, leading to an enhanced infection.

Acyclovir given as prophylaxis against oral ulcers in acute myeloid leukaemia: randomised, double blind, placebo controlled trial.

OBJECTIVES: To evaluate (a) the prophylactic effect of the antiherpetic drug acyclovir on oral ulcers in patients with acute myeloid leukaemia receiving remission induction chemotherapy and thus (b), indirectly, the role of herpes simplex virus in the aetiology of these ulcers. DESIGN: Randomised, double blind, placebo controlled trial. SUBJECTS: 74 herpes simplex virus seropositive patients aged 18-84. Thirty seven patients received acyclovir (800 mg by mouth daily) and 37 placebo. The patients were examined daily for 28 days. MAIN OUTCOME MEASURES: Occurrence of herpes labialis, intraoral ulcers, and acute necrotising ulcerative gingivitis. RESULTS: The two populations were comparable in age, sex, type of antineoplastic treatment, and history of herpes labialis. Acute oral infections occurred in 25 of the acyclovir treated patients and 36 of the placebo treated patients (relative risk 0.69 (95% confidence interval 0.55 to 0.87)). This difference was due to a reduction in the incidence of herpes labialis (one case versus eight cases; relative risk 0.13 (0.02 to 0.95)), intraoral ulcers excluding the soft palate (one case versus 13 cases; relative risk 0.08 (0.01 to 0.56)), and acute necrotising ulcerative gingivitis (one case versus eight cases; relative risk 0.13 (0.02 to 0.95)). However, ulcers on the soft palate were diagnosed with similar frequency in the two groups. Isolation of herpes simplex virus type 1 in saliva was reduced from 15 cases in the placebo group to one case in the acyclovir group (relative risk 0.07 (0.01 to 0.48)). CONCLUSION: Intraoral ulcers excluding the soft palate are most often due to infection with herpes simplex virus, whereas ulcers on the soft palate have a non-herpetic aetiology. The findings suggest that acute necrotising ulcerative gingivitis may also be due to herpes simplex virus. Prophylaxis with acyclovir should be considered for patients with acute myeloid leukaemia during remission induction therapy.

Autocrine secretion of interferon-alpha/beta and tumour necrosis factor-alpha synergistically activates mouse macrophages after infection with herpes simplex virus type 2.

Resistance of mice to infection with herpes simplex virus type 2 (HSV-2) is strongly dependent on the function of macrophages (M phi). Infection of mouse M phi with HSV-2 results in an early (4 to 10 h) activation of the cells with an enhanced respiratory burst generated after membrane triggering with a phorbol ester. The role of monokines produced during this infection was analysed. Both interferon-alpha/beta (IFN-alpha/beta) and tumour necrosis factor-alpha (TNF-alpha) were produced within the very first hours after infection of M phi with HSV-2. Exogenously added IFN-alpha/beta conferred to M phi a respiratory burst capacity comparable to that seen after virus infection, whereas TNF-alpha by itself was unable to prime M phi for a respiratory burst. In fact concentrations of TNF-alpha comparable to those found in HSV-2-infected M phi cultures generally suppressed the response. However, when TNF-alpha was added together with IFN-alpha/beta a dose-dependent synergistic enhancement of the IFN-induced M phi activation was seen. The kinetics of the synergistic activation by the two monokines was similar to that seen with IFN-alpha/beta alone. Neutralizing antibodies to IFN-alpha/beta and TNF-alpha were able to diminish the HSV-induced priming of M phi for a respiratory burst. When the two antibodies were used together in subneutralizing concentrations an additional diminution of the responsiveness was seen, indicating that both monokines are involved in the virus-induced priming of M phi. However, high concentrations of antibodies to IFN-alpha/beta alone were able to abolish the activation completely, whereas this was not the case with anti-TNF-alpha. Collectively these data demonstrate that autocrine secretion of IFN-alpha/beta by M phi infected with HSV-2 is a sine qua non for the activation of M phi during the infection, and that this effect of IFN is synergistically enhanced, also in an autocrine manner, by TNF-alpha. It is suggested that this reciprocal M phi-monokine interaction may be of importance in resistance to virus infections.

Genetically determined difference in the antiviral action of alpha/beta interferon in cells from mice resistant or susceptible to herpes simplex virus type 2.

Resistance of mice to infection with herpes simplex virus type 2 (HSV-2) is genetically determined. Embryonic cells from susceptible BALB/c and resistant C57BL/6 mice were equally sensitive to infection with HSV-2 as judged by plaque area, plaquing efficiency, endpoint titration and virus yield. Cells from C57BL/6 mice showed a higher sensitivity than cells from BALB/c mice to the protective action of two preparations of alpha/beta interferon against challenge with HSV-2. This was evident both from c.p.e. inhibition and yield reduction experiments. The difference in sensitivity was dependent on virus dose and was greatest (up to 50-fold) with low virus doses. An analysis of the genetics of the alpha/beta interferon sensitivity in cells from embryos of parental mice and embryos derived from reciprocal matings between HSV-2-resistant and -susceptible mice suggested that interferon sensitivity is inherited as a co-dominant autosomal trait. The induction of the interferon-induced enzyme 2'-5'-oligoadenylate synthetase was also different in cells from the two mouse strains, since significant levels were only detected in cells from C57BL/6 mice. It is suggested that differential interferon sensitivity of cells from HSV-2-resistant and -susceptible mice might be a factor of importance for the course of the infection.

Autointerference in silver accumulation in macrophages without affecting phagocytic, migratory or interferon-producing capacity.

Silver accumulation and processing in mouse peritoneal macrophages was studied in vitro by autometallographic visualization of intracellular silver. During the first 24 h of incubation in a medium containing from 5 microM to 20 microM of silver lactate, an inverse relationship between silver concentration in the former and visualizable silver in macrophages was recorded. Later, however, the cells treated with higher silver concentrations accumulated most silver. Cells exposed to silver concentrations above these levels exhibited acute coagulation necrosis and disintegrated within the first 15 min of silver treatment. Macrophages treated with silver lactate concentrations not causing acute cytotoxicity showed no impairment of their phagocytic, migratory or interferon-producing capacities. The significance of autointerference in silver accumulation and processing in macrophages is discussed, and a functional defect in the lysosome/phagosome system is suggested as a basis for the phenomenon.

Effects of selenium on toxicity and ultrastructural localization of silver in cultured macrophages.

The effects of selenium on cellular toxicity and histochemical distribution of silver were examined in a cell culture system of mouse peritoneal macrophages. Selenium caused a significant delay in the appearance of coagulation necrosis induced by high silver concentrations and reduced the cytostatic effect of lower doses of silver when long-term toxicity was examined. Furthermore, selenium increased the amount of silver that could be visualized by autometallography. The additional silver made available for this histochemical demonstration was located in the cytosol as well as in lysosomes, the sole localization of silver when selenium was not administered.