Point-prevalence surveillance of healthcare-associated infections in Swedish hospitals, 2008-2014. Description of the method and reliability of results.

BACKGROUND: In 2007 the Swedish Association of Local Authorities and Regions (SALAR) decided to establish a nationwide system for point-prevalence surveillance of healthcare-associated infections (HCAIs) among hospitalized patients. Surveillance started in 2008 and has since then been performed twice a year (April and October). The documentation of HCAIs is performed by regular clinical physicians and nurses on each hospital ward aided by oral and written instructions. All Swedish publicly financed hospitals (>95% of all hospitals) are included (25,862 beds in 2008 and 24,905 beds in 2013). A total of 88-92% of all inpatients has been covered in each survey. The overall prevalence of HCAI (including psychiatric inpatients) has ranged from 7.8% to 10.0%. AIM: In 2012 SALAR decided to assess the reliability of the prevalence data. METHODS: In all, 1216 patients were assessed for HCAIs by both the regular surveillance teams and teams with expert knowledge on HCAI independently of each other. FINDINGS: The prevalence of HCAI was 8.3% (95% confidence interval: 6.7-9.9) according to the regular teams and 13.1% (11.2-15.0) according to the expert teams. The sensitivity of the regular point-prevalence surveillance was 47% and the specificity 97%. CONCLUSION: The Swedish system for repeated nationwide point-prevalence surveillance of HCAI has had a high coverage of about 90% since it commenced. However, the surveys underestimate the true prevalence of HCAI.

Interleukin-17-producing T-helper cells and related cytokines in human airways exposed to endotoxin.

Previous studies on mouse models have indicated that interleukin (IL)-17 and IL-17-producing T-helper (Th) cells are important for pulmonary host defence against Gram-negative bacteria. Human correlates to these findings have not yet been demonstrated. The aim of the present study was to determine whether or not IL-17-producing Th cells are present and whether IL-17 and other Th17-associated cytokines are involved in the immunological response to endotoxin in human airways. Segmental exposure to endotoxin and contralateral exposure to vehicle were performed in the lungs of healthy volunteers, with subsequent bronchoalveolar lavage 12 or 24 h after exposure to study local changes in cytokines and inflammatory cells. Endotoxin exposure increased concentrations of IL-17, IL-22 and their downstream effector molecules, human ß-defensin-2 and IL-8/CXC chemokine ligand 8, in bronchoalveolar lavage fluid. Th cells with the capacity to produce IL-17 were found among the bronchoalveolar lavage cells, and expression of IL-17 mRNA correlated with expression of the transcription factor, retinoic-acid-receptor-related orphan receptor C variant 2. Moreover, endotoxin increased the numbers of neutrophils, macrophages and IL-17-producing T-cells, as well as the concentration of the Th17-regulating cytokines, IL-21 and IL-23. In conclusion, IL-17-producing Th cells are present, and IL-17, as well as other Th17-associated cytokines, is involved in the immunological response to endotoxin in human airways.

Effective control measures limited measles outbreak after extensive nosocomial exposures in January-February 2008 in Gothenburg, Sweden.

In January-February 2008, one imported case of measles initiated a series of exposures with around 380 nosocomial secondary contacts. Susceptible individuals were traced early and control measures were initiated that managed to limit the consequences considerably. Only four secondary cases were identified by the end of March. This minor outbreak illustrates the importance and efficiency of early control measures as well as the fact that the risk of measles outbreaks still exists in a country that has high measles, mumps, rubella vaccination coverage among children.

Impact of acute exposure to tobacco smoke on gelatinases in the bronchoalveolar space.

Clinical studies have indicated increased gelatinase activity in the airways of patients suffering from chronic obstructive pulmonary disease caused by tobacco smoke. The present study aimed to determine whether acute exposure to tobacco smoke per se causes a substantial and lasting impact on gelatinases and their inhibitors in the peripheral airways of atopic and nonatopic human subjects. Bronchoscopy with bronchoalveolar lavage (BAL) was performed on occasional smokers with and without atopy before and after smoking 10 cigarettes over a 48-h period. Samples from a group of never-smokers not exposed to tobacco smoke served as controls. Gelatinase identity and activity were measured using zymography, and gelatinase activity assay and concentrations of matrix metalloproteinase (MMP)-2, MMP-9, tissue inhibitor of MMP (TIMP)-1 and TIMP-2 were measured using ELISA. The results revealed no pronounced changes in identity, net activity or concentration of the gelatinases or changes in concentrations of TIMP-1 and TIMP-2 in BAL fluid before and after acute exposure to tobacco smoke. In conclusion, the present experimental study indicates that acute exposure to tobacco smoke does not cause any substantial impact on gelatinases or their inhibitors in the peripheral airways, irrespective of atopy status, a finding that is compatible with the fact that it takes many years of tobacco smoking to establish chronic obstructive pulmonary disease.

Impact of tobacco smoke on interleukin-16 protein in human airways, lymphoid tissue and T lymphocytes.

CD4(+) and CD8(+) lymphocytes are mobilized in severe chronic obstructive pulmonary disease (COPD) and the CD8(+) cytokine interleukin (IL)-16 is believed to be important in regulating the recruitment and activity of CD4(+) lymphocytes. In the current study, we examined whether tobacco smoke exerts an impact not only on IL-16 in the lower airways but also in CD4(+) or CD8(+) lymphocytes or in lymphoid tissue. The concentration of IL-16 protein was measured by enzyme-linked immunosorbent assay (ELISA) in concentrated bronchoalveolar lavage fluid (BALF) collected from 33 smokers with chronic bronchitis (CB), eight asymptomatic smokers (AS) and seven healthy never-smokers (NS). The concentrations of IL-16 and soluble IL-2 receptor alpha (sIL-2Ralpha) protein were also measured in conditioned medium from human blood CD4(+) and CD8(+) lymphocytes stimulated with tobacco smoke extract (TSE) in vitro. IL-16 mRNA was assessed in vitro as well, using reverse transcription-polymerase chain reaction (RT-PCR). Finally, the intracellular immunoreactivity for IL-16 protein (IL-16IR) was assessed in six matched pairs of palatine tonsils from smokers and non-smokers. BALF IL-16 was higher in CB and AS than in NS. TSE substantially increased the concentration of IL-16 but not sIL-2Ralpha in conditioned medium from CD4(+) and CD8(+) lymphocytes. There was no corresponding effect on IL-16 mRNA. IL-16IR in tonsils was lower in smokers than in non-smokers. The current findings demonstrate that tobacco smoke exerts a wide impact on the CD8(+) cytokine IL-16, in the airway lumen, in blood CD4(+) and CD8(+) lymphocytes and in lymphoid tissue. The effect on IL-16 release may be selective for preformed IL-16 in CD4(+) lymphocytes. New clinical studies are required to evaluate whether tobacco smoke mobilizes T lymphocytes via IL-16 in the lower airways and whether this mechanism can be targeted in COPD.

IgG subclasses in smokers with chronic bronchitis and recurrent exacerbations.

BACKGROUND: Tobacco smokers have lower serum levels of IgG than non-smokers. IgG subclass deficiency is common in patients with recurrent respiratory infections. Recurrent bronchial infections are common in smokers with chronic bronchitis (CB). We have investigated whether susceptibility to recurrent exacerbations in smokers with CB is associated with altered IgG subclass levels or IgG subclass deficiency. METHODS: Serum levels of IgG, IgA, IgM, and IgG subclasses 1-4 were determined by radial immunodiffusion in 100 subjects: 33 smokers with stable CB and recurrent exacerbations, 24 asymptomatic smokers, and 43 healthy never smokers. Systemic tobacco exposure was verified and excluded using a serum cotinine ELISA. Immunoglobulin data were log transformed to enable use of parametric statistical methods. RESULTS: Compared with never smokers, both patients with CB and asymptomatic smokers had significantly lower levels of IgG (median 9.7 g/l (range 5.6-15.2) and 9.9 (6.1-12.1) g/l v 12.0 (6.9-18.5) g/l) and IgG2 (2.8 (0.9-5.9) g/l and 2.5 (1.0-6.3) g/l v 4.0 (1.7-10.2) g/l). The estimated ratio of median values between the patients with CB and never smokers was 0.78 (95% confidence interval (CI) 0.69 to 0.89) for IgG and 0.65 (95% CI 0.50 to 0.83) for IgG2. The corresponding ratios between asymptomatic smokers and never smokers were 0.79 (95% CI 0.69 to 0.91) and 0.60 (95% CI 0.50 to 0.83), respectively. There were no significant differences between the smoking groups. CONCLUSIONS: Susceptibility to recurrent exacerbations in smokers with CB is not associated with lower levels of IgG subclasses than can be accounted for by smoking per se.

Inhibitory effect of N-acetylcysteine on adherence of Streptococcus pneumoniae and Haemophilus influenzae to human oropharyngeal epithelial cells in vitro.

BACKGROUND: Bacterial adherence to mucosal and epithelial cell structures is of importance for the persistence of bacteria in the airways. Cigarette smoking and chronic bronchitis are associated with increased bacterial adherence. N-Acetylcysteine (NAC) medication reduces the number of infectious exacerbations in patients with chronic bronchitis, and NAC medication has been associated with low intrabronchial bacterial numbers. OBJECTIVE: We investigated whether NAC influences bacterial adherence as a possible mechanism behind its clinical effects. METHODS: Highly adhering test strains of Streptococcus pneumoniae and Haemophilus influenzae were used to investigate the influence of four pharmacological compounds on adherence to oropharyngeal epithelial cells in vitro. Adhesion assays were performed both during short-term exposure to, as well as after long-time incubation with, NAC, lidocaine, hydrocortisone and terbutaline at concentrations not inhibiting bacterial growth. RESULTS: Only NAC showed a significant inhibitory effect on adhesion of H. influenzae during short-term incubation. After long-term incubation, both NAC and hydrocortisone inhibited bacterial adhesion for both strains in a dose-dependent manner. When NAC's effect on three different strains of S. pneumoniae and four strains of H. influenzae was studied, inhibition of bacterial adhesion was found for three strains of each species. CONCLUSIONS: NAC lowers bacterial adhesion in vitro to oropharyngeal epithelial cells in doses equivalent to that is being used clinically. This effect might be a contributory mechanism behind the reduction of infectious exacerbations in chronic bronchitis patients.

Lower airway bacterial colonization in asymptomatic smokers and smokers with chronic bronchitis and recurrent exacerbations.

Bacterial colonization of the lower airways in patients with chronic bronchitis (CB) has been described mainly in patients with co-existing chronic obstructive pulmonary disease (COPD). Although smoking has been identified as a risk factor for bacterial colonization it is not known whether asymptomatic smokers (AS) can be colonized. The aim of this study was to study lower airway bacterial colonization in smokers with stable CB and recurrent exacerbations and compare with AS and healthy never-smokers (NS). Thirty-nine smokers with CB and recurrent exacerbations (median FEV1 85% of predicted normal), 10 AS and 10 NS, underwent bronchoscopy and a two-step bronchoalveolar lavage (BAL) procedure where the first portion (20 ml, 'pre-BAL') was recovered separately from the rest (140 ml, 'BAL'). The degree of oropharyngeal contamination of pre-BAL and BAL samples was evaluated by cytology. Semiquantitative bacterial cultures were performed on all samples. Higher bacterial numbers than 10(3) colony-forming units (cfu) x ml(-1) in BAL were found only in the two smoking groups. Using 10(3) cfu x ml(-1) as cut-off, 6/10 (60%) in the AS-, and 7/35 (20%) in the CB-group were colonized in the lower airways. In all, 29% of all smokers had bacterial colonization. Only bacteria belonging to the normal oropharyngeal flora were found. The proportion of samples with oropharyngeal contamination was significantly lower in BAL than in pre-BAL (5% vs. 21%, P=0.039). The proportion of sterile samples was significantly higher in BAL than in pre-BAL (49% vs. 26%, P=0.002). Lower airway bacterial colonization was found both in asymptomatic smokers and in patients with CB. Colonization with potential respiratory pathogens is uncommon in patients with CB and recurrent exacerbations without severe airflow obstruction. The two-step BAL procedure seems to decrease oropharyngeal contamination.

Increased levels of interleukin-16 in the airways of tobacco smokers: relationship with peripheral blood T lymphocytes.

BACKGROUND: The mechanisms behind the development of systemic immunomodulation among tobacco smokers are not fully understood, but several studies have indicated a role for CD8+ and/or CD4+ T cells. Interleukin (IL)-16, a cytokine released from inflammatory cells as well as bronchial epithelial cells, can recruit and activate CD4+ T cells. A study was undertaken to establish whether the IL-16 level is increased in the airways of tobacco smokers and to determine whether airway levels of IL-16 are related to the number and function of systemic T lymphocytes. METHODS: Bronchoalveolar lavage (BAL) fluid was collected from eight never smokers and 18 tobacco smokers without clinical airway symptoms, and from 16 tobacco smokers with clinical airway symptoms. Interleukin-16 protein levels in BAL fluid were determined using enzyme-linked immunosorbent assay (ELISA). Peripheral blood was collected for determination of CD4+ T cell content using flow cytometry. The responsiveness of systemic lymphocytes in smokers was assessed by measuring the proliferative response of peripheral blood lymphocytes to the superantigen staphylococcus enterotoxin A (SEA). RESULTS: The IL-16 protein level in the BAL fluid was significantly higher in tobacco smokers than in non-smokers. However, among tobacco smokers the IL-16 level was similar in asymptomatic smokers and in those with airway symptoms. The level of IL-16 in the BAL fluid of smokers correlated negatively with the percentage of CD4+ T cells and positively with superantigen stimulated lymphocyte proliferation in peripheral blood. CONCLUSIONS: In tobacco smokers the airway IL-16 level is increased and it is possible that this increase in IL-16 influences systemic immunomodulation by altering the number and responsiveness of systemic T lymphocytes.

Cutaneous delayed-type hypersensitivity reactions in smokers with chronic bronchitis and recurrent exacerbations: comparison with asymptomatic smokers and never-smokers.

The aim of the present study was to investigate whether smoking patients with chronic bronchitis (CB) and recurrent exacerbations show signs of depressed cell-mediated immunity (CMI), as reflected in the cutaneous delayed-type hypersensitivity (DTH) reaction, in comparison with asymptomatic smokers and healthy never-smokers. The study was a comparative clinical study performed at a university hospital center of respiratory medicine. Sixteen smokers with stable CB and recurrent exacerbations, five of whom had mild airflow obstruction, 18 asymptomatic smokers and 18 healthy never-smokers, all aged between 35 and 64 years, participated. No subjects treated with corticosteroids or N-acetylcysteine were included. Cutaneous DTH-reactions to seven recall antigens were assessed with Multitest, a standardized in vivo test of clinical CMI. Reactions were assessed 48 h after application by measurement of skin induration. A score (sum in mm of positive reactions) was created to assess overall reactivity. Neither the score nor the number of positive reactions differed significantly between the three study groups. Men had a significantly higher reactivity than women (P < 0.05) irrespective of group affiliation. No influence of smoking status on DTH reactivity could be seen. In the CB group no correlation was found between DTH reactivity and number of exacerbations the past 2 years. Patients with chronic bronchitis and recurrent exacerbations did not differ from asymptomatic smokers or healthy never-smokers with respect to cutaneous DTH reactions. Depression of CMI, as measured in this study, does not seem to be a primary factor behind recurrent exacerbations in smokers with CB.

Immunological findings in blood and bronchoalveolar lavage fluid in chronic bronchitis patients with recurrent infectious exacerbations.

Bronchial infections are common in smokers and seem to be related to the presence of chronic bronchitis (CB). Why only some smokers develop repeated bronchial infections is not known. The aim of this study was to screen for immunological changes associated with disease in patients with CB and recurrent infectious exacerbations compared to asymptomatic smokers. Sixteen smokers with stable CB and recurrent infectious exacerbations, and 18 asymptomatic smokers, all without any immunomodulating treatment, underwent bronchoscopy and bronchoalveolar lavage (BAL). Smoking history and current smoking status were comparable. Serum levels of immunoglobulin (Ig)A, IgM, IgG and IgG subclasses were measured. Blood and BAL lymphocyte phenotypes and proliferative responses of peripheral blood mononuclear cells (PBMCs) to various stimulators were analysed. Unstimulated and tetanus toxoid-stimulated production of cytokines in PBMC cultures was measured. Natural killer (NK-) cell activity was analysed. A significantly (p<0.05) lower level of IgG3 was found in the CB group, and a significantly (p<0.01) higher proliferative response of PBMCs was found in the CB group after stimulation with diphtheria toxoid. Detectable levels of interleukin (IL)-6, tumour necrosis factor-alpha (TNF-alpha) and interferon-gamma, but not of IL-2, IL-4 or transforming growth factor-beta2, were found in supernatants from cultured cells in both study groups. Stimulated TNF-alpha production was significantly (p<0.05) higher in the CB group. NK-cell activity did not differ significantly between the study groups. There were no major differences between the groups in lymphocyte subpopulations in blood or BAL. In conclusion, no major alterations in the analysed indices of cell-mediated and humoral immunity were found in patients with chronic bronchitis prone to recurrent infectious exacerbations when compared with asymptomatic smoking controls.