Comparison of serological assays using pneumococcal proteins or polysaccharides for detection of Streptococcus pneumoniae infection in children with community-acquired pneumonia.

The aim of this study was to compare the results of serological assays using pneumococcal proteins or polysaccharides for the detection of pneumococcal infection in childhood pneumonia. Serological assays measured IgG against eight pneumococcal proteins (Ply,CbpA,PspA1,PspA2,PcpA,PhtD,StkP-C,PcsB-N), C-polysaccharide [in the whole study population, n = 183], or 19 pneumococcal capsular polysaccharides (1,2,4,5,6B,7F,8,9 V,10A,11A,12F,14,15B,17F,18C,19F,20,23F,33F) [only in a subgroup of patients, n = 53] in paired serum samples of children aged <5 years-old hospitalized with clinical and radiological diagnosis of community-acquired pneumonia. We also performed an inhibition of binding test with the anti-capsular polysaccharide assay in order to confirm the specificity of the antibody responses detected. Invasive pneumococcal pneumonia was investigated by blood culture and PCR (ply-primer). Among 183 children, the anti-protein assay detected antibody response in 77/183(42.1%) patients and the anti-C-polysaccharide assay in 28/183(15.3%) patients. In a subgroup of 53 children, the anti-protein assay detected response in 32/53(60.4%) patients, the anti-C-polysaccharide assay in 11/53(20.8%) patients, and the anti-capsular polysaccharide in 25/53(47.2%) patients. Simultaneous antibody responses against ≥2 different capsular polysaccharides were detected in 11/53(20.8%) patients and this finding could not be explained by cross-reactivity between different serotypes. Among 13 patients with invasive pneumococcal pneumonia, the sensitivity of the anti-protein assay was 92.3%(12/13), of the anti-C-polysaccharide assay 30.8%(4/13), and of the anti-capsular polysaccharide assay 46.2%(6/13). The serological assay using pneumococcal proteins is more sensitive for the detection of pneumococcal infection in children with pneumonia than the assay using pneumococcal polysaccharides. Future studies on childhood pneumonia aetiology should consider applying serological assays using pneumococcal proteins.

The effect of proatherogenic pathogens on adipose tissue transcriptome and fatty acid distribution in apolipoprotein E-deficient mice.

BACKGROUND: Chronic infections have been demonstrated to maintain low-grade systemic inflammation and associate with atherosclerosis. We studied the inflammation- and lipid homeostasis-related effects of Aggregatibacter actinomycetemcomitans (Aa) and Chlamydia pneumoniae (Cpn) infections on the epididymal and inguinal adipose tissue (AT) transcriptomes and fatty acid distribution in apolipoprotein (apo) E-deficient mice. Chow-fed apoE-deficient mice were exposed to 1) chronic intranasal infection with C. pneumoniae (Cpn group), 2) recurrent intravenous infection with A. actinomycetemcomitans (Aa group), 3) a combination of both types of infection (Cpn + Aa group), or 4) infection with the vehicle (control group). Epididymal and inguinal AT gene expression was analyzed using an Illumina Mouse WG-6 v2.0 platform and quantitative PCR (QPCR). Microarray data were analyzed using Gene Ontology enrichment analysis. AT fatty acid analysis was performed using gas-liquid chromatography. RESULTS: The transcriptomics data revealed significant enrichment in inflammation-associated biological pathways in both AT depots derived from the Aa and Cpn + Aa treated mice compared with the control group. The proportion of saturated fatty acids was higher in the inguinal AT in Aa (p = 0.027) and Cpn + Aa (p = 0.009) groups and in the epididymal AT in Aa group (p = 0.003). The proportion of polyunsaturated fatty acids was significantly lower among all Aa-infected groups in both depots. Chronic Cpn infection displayed only minor effects on transcriptomics and fatty acids of the AT depots. CONCLUSIONS: Systemic infection with A. actinomycetemcomitans activates inflammation-related biological pathways and modulates cellular lipid homeostasis. The adverse changes in adipose tissues during chronic infection may promote atherosclerosis.

Respiratory viral infections among children with community-acquired pneumonia and pleural effusion.

Pleural effusion (PE), a complication of community-acquired pneumonia (CAP), is usually attributed to a bacterial infection. Nonetheless, viral infections have not been investigated routinely. We searched for bacterial and viral infections among 277 children hospitalized with CAP. Among these children 206 (74%) had radiographic confirmation, of whom 25 (12%) had PE. The aetiology was established in 18 (72%) PE cases: bacterial (n = 5; 28%), viral (n = 9; 50%), and viral-bacterial (n = 4; 22%) infections were found. Infection by rhinovirus (n = 3), enterovirus, Streptococcus pneumoniae (n = 2 each), Haemophilus influenzae, Moraxella catarrhalis, Mycoplasma pneumoniae, influenza A virus, and respiratory syncytial virus (RSV) (n = 1 each) were detected as probable sole infections. Parainfluenza virus 1/3 + influenza A virus and RSV + influenza A virus (n = 1 each) were identified as mixed viral-viral infections. Probable viral non-bacterial infection was identified in a third of the cases with CAP and PE. It is advisable to investigate viral as well as bacterial infections among children with CAP and PE.

Nasopharyngeal carriage of Streptococcus pneumoniae and pneumococcal urine antigen test in healthy elderly subjects.

BACKGROUND: Children frequently carry Streptococcus pneumoniae (pneumococcus) in their nasopharynx, even when healthy. Lower carriage rates have been reported in adults and only sparse data are available for the elderly. We sampled healthy elderly subjects for nasopharyngeal carriage to assess the prevalence of pneumococcal carriage using various assays. METHODS: A deep nasopharyngeal swab sample was taken from 590 healthy elderly subjects aged ≥ 65 y. The samples were stored in STGG (skim milk-tryptone-glucose-glycerol) medium and cultured directly and after incubation in enrichment broth using routine identification methods. Real-time polymerase chain reaction (PCR) assays specific for pneumolysin and pneumococcal surface antigen A genes was performed on the same samples. Urine was also collected and assayed using the commercial Binax Streptococcus pneumoniae NOW urine antigen test. RESULTS: The prevalence of pneumococcal carriage in healthy elderly persons was 1.5% for encapsulated pneumococci and 5.3% for all presumptive pneumococci. The use of the enrichment broth did not increase the yield of positives. PCR assays gave higher numbers of positives, but pneumolysin PCR in particular gave probable false-positive results. Only 1 urine antigen test was positive, and this was in a person not carrying pneumococcus. CONCLUSIONS: Nasopharyngeal carriage of pneumococci in the elderly was rare. Identification of presumptive pneumococci in culture requires further confirmation, e.g. by serotyping. The urine antigen test was not affected by concurrent carriage. Low carriage prevalence suggests that encapsulated pneumococci detected in a respiratory tract sample during sickness may be the true cause of disease, since contamination from asymptomatic nasopharyngeal carriage seems unlikely.

Genotypic and phenotypic characterization of carriage and invasive disease isolates of Neisseria meningitidis in Finland.

The relationship between carriage and the development of invasive meningococcal disease is not fully understood. We investigated the changes in meningococcal carriage in 892 military recruits in Finland during a nonepidemic period (July 2004 to January 2006) and characterized all of the oropharyngeal meningococcal isolates obtained (n = 215) by using phenotypic (serogrouping and serotyping) and genotypic (porA typing and multilocus sequence typing) methods. For comparison, 84 invasive meningococcal disease strains isolated in Finland between January 2004 and February 2006 were also analyzed. The rate of meningococcal carriage was significantly higher at the end of military service than on arrival (18% versus 2.2%; P < 0.001). Seventy-four percent of serogroupable carriage isolates belonged to serogroup B, and 24% belonged to serogroup Y. Most carriage isolates belonged to the carriage-associated ST-60 clonal complex. However, 21.5% belonged to the hyperinvasive ST-41/44 clonal complex. Isolates belonging to the ST-23 clonal complex were cultured more often from oropharyngeal samples taken during the acute phase of respiratory infection than from samples taken at health examinations at the beginning and end of military service (odds ratio [OR], 6.7; 95% confidence interval [95% CI], 2.7 to 16.4). The ST-32 clonal complex was associated with meningococcal disease (OR, 17.8; 95% CI, 3.8 to 81.2), while the ST-60 clonal complex was associated with carriage (OR, 10.7; 95% CI, 3.3 to 35.2). These findings point to the importance of meningococcal vaccination for military recruits and also to the need for an efficacious vaccine against serogroup B isolates.

Corn mint (Mentha arvensis) extract diminishes acute Chlamydia pneumoniae infection in vitro and in vivo.

Corn mint ( Mentha arvensis ) provides a good source of natural phenols such as flavone glycosides and caffeic acid derivatives, which may have prophylactic properties against inflammations. This study investigated whether corn mint extract would be beneficial against a universal respiratory tract pathogen, Chlamydia pneumoniae , infection. The extract inhibited the growth of C. pneumoniae CWL-029 in vitro in a dose-dependent manner. The inhibition was confirmed against a clinical isolate K7. The phenolic composition of the extract was analyzed by UPLC-ESI/Q-TOF/MS, the main components being linarin and rosmarinic acid. These compounds were active in vitro against C. pneumoniae. Linarin completely inhibited the growth at 100 µM. Inbred C57BL/6J mice were inoculated with C. pneumoniae K7. M. arvensis extract was given intraperitoneally once daily for 3 days prior to inoculation and continued for 10 days postinfection. The extract was able to diminish the inflammatory parameters related to C. pneumoniae infection and significantly (p = 0.019) lowered the number of C. pneumoniae genome equivalents detected by PCR at biologically relevant amounts.

Effects of coadministration of natural polyphenols with doxycycline or calcium modulators on acute Chlamydia pneumoniae infection in vitro.

Besides small molecules from medicinal chemistry, natural products are still major sources of innovative therapeutic agents for various conditions, including infectious diseases. Here we present the first attempt to design a combination treatment targeted against Chlamydia pneumoniae infection using coadministration of natural phenolics with calcium (Ca(2+)) modulators, and also the concomitant administration of these compounds with doxycycline. An in vitro acute C. pneumoniae model in human lung epithelial cells was used and Loewe additivity model was applied to evaluate the effects. In general, the phenolic compounds, quercetin, luteolin, rhamnetin and octyl gallate did not improve the antichlamydial effect of doxycycline, and, in some cases, resulted in antagonistic effects. The combination of doxycycline and Ca(2+) modulators (isradipine, verapamil and thapsigargin) was at most additive, and at subinhibitory concentrations of doxycycline, often even antagonistic. The Ca(2+) modulators showed no inhibitory effects on C. pneumoniae growth alone, whereas the coadminstration of Ca(2+) modulators with phenolic compounds resulted in potentiation of the antichlamydial effect of phenolic compounds. Verapamil (100 µM) was synergistic with low quercetin and luteolin concentrations (0.39 and 1.56 µM), whereas 10 µM isradipine was synergistic with high quercetin, rhamnetin and octyl gallate concentrations (12.5 µM and 100 µM). Use of thapsigargin with the phenolic compounds resulted in the most intense synergism. Interaction indices 0.12 and 0.14 were achieved with 0.39 µM luteolin and 10 and 100 nM thapsigargin, respectively. To conclude, the observed results indicate that the Ca(2+) modulators potentiate the antichlamydial effects of the phenolic compounds.

The effect of proatherogenic microbes on macrophage cholesterol homeostasis in apoE-deficient mice.

BACKGROUND: Pathogens such as Aggregatibacter actinomycetemcomitans (Aa) and Chlamydia pneumoniae (Cpn) associate with an increased risk for cardiovascular diseases by inducing inflammation. We hypothesized that the pathogens affect the vascular wall by disturbing cholesterol homeostasis and endothelial function. METHODS: Aa- and Cpn-infections were induced in apoE-deficient mice by intravenous and intranasal applications, respectively. Cholesterol efflux from mouse peritoneal macrophages to apo(lipoprotein)A-I was assessed. The efflux capacity of mouse sera as acceptors of cholesterol from RAW264.7-macrophages was determined. Additionally, endothelial function was studied by following the relaxation capacity of rat mesenteric arteries after incubation in the conditioned culture media of the peritoneal macrophages isolated from the mice. RESULTS: Infection increased serum phospholipid transfer protein (PLTP) and lipopolysaccharide (LPS) activity, as well as serum amyloid A (SAA) and TNF-α concentrations. Peritoneal macrophages of mice with Aa-infection showed increased cholesterol uptake and reduced cholesterol efflux. Sera of Cpn and Cpn + Aa-infected mice had reduced cholesterol efflux capacity from RAW264.7-macrophages. Conditioned macrophage medium from mice with chronic C. pneumoniae infection induced endothelial dysfunction. Additionally, concentrations of serum adhesion molecules, intercellular adhesion molecule (ICAM) and vascular cell adhesion molecule (VCAM) in Cpn-groups and E-selectin in Cpn + Aa-group, were elevated. The serum markers of endothelial function correlated positively with SAA. CONCLUSIONS: Aa- and Cpn-infections may generate proatherogenic changes in the vascular wall by affecting the macrophage cholesterol homeostasis and endothelial function.

Effect of xylitol and other carbon sources on Streptococcus pneumoniae biofilm formation and gene expression in vitro.

Xylitol inhibits the growth of Streptococcus pneumoniae. In clinical trials, xylitol decreased the occurrence of acute otitis media in day-care children, but did not decrease nasopharyngeal carriage of pneumococci. We hypothesized that xylitol inhibits biofilm formation of pneumococci, and measured biofilm formation and gene expression levels of the capsule gene cpsB and two other genes: autolysin encoding gene lytA and competence gene comA in different growth media in vitro. Twenty pneumococcal isolates were grown on polystyrene plates for 18 h in test media containing 0.5% xylitol, 0.5% glucose, 0.5% xylitol and 0.5% glucose, 0.5% fructose, 0.5% xylitol and 0.5% fructose or brain heart infusion (BHI) medium supplemented with 10% horse serum. Gene expression levels were measured after 5 h of growth using a relative quantification method with calibrator normalization. Exposure to xylitol lowered OD values, which were used as an indication of biofilm, compared with BHI medium, but when the medium was supplemented with glucose or fructose, biofilm formation was enhanced and the inhibitory effect of xylitol on biofilm formation was not observed. Xylitol also lowered lytA expression levels. Changes in biofilm formation in response to different sugar compounds may partly explain the efficacy of xylitol to prevent acute otitis media in previous clinical trials.

Association of IL-6 and IL-6R gene polymorphisms with susceptibility to respiratory tract infections in young Finnish men.

Interleukin-1 (IL-6) is an important mediator of inflammatory response in the respiratory tract during an infection, and the action of IL-6 is mediated by an IL-6 receptor. Several polymorphisms in the IL-6 and IL-6R genes have been associated with different inflammatory disease states. We studied the association between 2 IL-6 (IL6A and IL6B) and 5 IL-6R gene polymorphisms (IL6R1 to IL6R5) and respiratory infections in 511 Finnish military recruits whose respiratory infectious episodes were followed during 6 months of service. A promoter polymorphism of the IL-6R gene, IL6R1 (-183G/A), and two intron 1 polymorphisms, IL6R2 (A/G) and IL6R3 (T/A), were associated with infections. The strongest associations were found for the IL6R1 and IL6R2 polymorphisms, which were in the same linkage disequilibrium block. Conscripts with the A/A (IL6R1), G/G (IL6R2), and A/A (IL6R3) genotypes had an increased risk for respiratory infections during service as follows: odds ratio (OR) 1.72, 95% confidence interval (CI) 1.35-2.19; OR 1.66, 95% CI 1.23-2.26; and OR 1.23, 95% CI 0.98-1.55, respectively. IL-6 gene polymorphism IL6A (-174C/G) was associated with infections only in combination with an IL-6R polymorphism. Our data suggest that polymorphisms in the 5' area of the IL-6R gene may be associated with increased susceptibility to respiratory infections.

Low mannose-binding lectin levels and MBL2 gene polymorphisms associate with Chlamydia pneumoniae antibodies.

OBJECTIVE: Mannose-binding lectin (MBL) has been shown to inhibit infection of host cells by Chlamydia pneumoniae in vitro. We studied if MBL levels and MBL2 polymorphisms associate with the presence of C. pneumoniae antibodies in vivo. MATERIALS AND METHODS: Single nucleotide polymorphisms (SNPs) of the MBL2 gene (promoter alleles H/L, X/Y and P/Q; and exon 1 variant alleles B, C and D and wild-type allele A) were genotyped and serum MBL concentrations and C. pneumoniae IgG, IgA and IgM antibodies were analysed in 889 Finnish military recruits. RESULTS: An MBL level below the median concentration and the MBL2 P/P genotype were significant risk factors of IgG or IgA seroconversions or the presence of IgM antibodies during military service (adjusted odds ratio (OR) 1.5; 95% confidence interval (CI) 1.1-2.1 and OR 1.5; 95% CI 1.0-2.2, respectively). In addition, the promoter Y/Y (OR 1.6; 95% CI 1.1-2.3) and exon 1 variant allele genotypes (OR 1.4; 95% CI 1.0-2.0) were possibly associated with elevated antibodies. CONCLUSIONS: These results suggest, for the first time, that low serum MBL levels and MBL2 polymorphisms may associate with elevated C. pneumoniae antibodies and seroconversions and thus support the previous findings in vitro.

Pneumococcal carriage is more common in asthmatic than in non-asthmatic young men.

INTRODUCTION: The aim was to investigate the prevalence of oropharyngeal carriage of Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis, Neisseria meningitidis and beta-haemolytic streptococci among asthmatic and non-asthmatic young Finnish men and to identify putative risk factors. OBJECTIVES: A total of 224 asthmatics and 668 non-asthmatic men (mean age 19.6 years) from two intakes of conscripts to the Kainuu Brigade, Finland in July 2004 and January 2005 were enrolled upon entering military service. METHODS: Oropharyngeal specimens were examined for bacteria by routine culture methods. All the participants filled in questionnaires concerning risk factors for asthma and respiratory infections. RESULTS: S. pneumoniae (48 cases, 5.4%), Group A streptococci (16, 1.8%), H. influenzae (45, 5.0%), M. catarrhalis (24, 2.7%) and N. meningitidis (20, 2.2%) were isolated from the 892 participants. Ten putative risk factors for oropharyngeal colonization (asthma, atopy, allergic rhinitis, smoking, current use of asthma medication, history of adeno/tonsillectomy, level of highly sensitive C-reactive protein, peak expiratory flow, results of a 12-min running test and body mass index) were evaluated. The only significant risk factor for S. pneumoniae carriage was asthma (OR, 2.04; 95% CI 1.12 to 3.72). CONCLUSIONS: Pneumococcal carriage is more common in asthmatic than in non-asthmatic young men.

Risk of invasive pneumococcal infections among working age adults with asthma.

BACKGROUND: Information about the risk of invasive pneumococcal infection (IPI) among adults with asthma is limited and inconsistent. To evaluate this association, a population-based case-control study was conducted. METHODS: Cases of IPI (Streptococcus pneumoniae isolated from blood or cerebrospinal fluid) were identified through national, population-based laboratory surveillance during 1995-2002. To maximise exclusion of chronic obstructive pulmonary disease, the analysis was limited to patients aged 18-49 years and 10 selected age-, sex- and health district-matched controls for each case from the Population Information System. Information on underlying medical conditions was obtained through linking surveillance data to other national health registries. Asthma requiring > or =1 hospitalisation in the past 12 months was defined as high risk asthma (HRA); low risk asthma (LRA) was defined as entitlement to prescription drug benefits and no hospitalisation for asthma in the past 12 months. RESULTS: 1282 patients with IPI and 12 785 control subjects were identified. Overall, 7.1% of cases and 2.5% of controls had asthma (6.0% and 2.4% had LRA whereas 1.1% and 0.1% had HRA, respectively. After adjustment for other independent risk factors in a conditional logistic regression model, IPI was associated with both LRA (matched OR (mOR) 2.8; 95% CI 2.1 to 3.6) and HRA (mOR, 12.3; 95% CI 5.4 to 28.0). The adjusted population-attributable risk was 0.039 (95% CI 0.023 to 0.055) for LRA and 0.01 (95% CI 0.0035 to 0.017) for HRA. CONCLUSIONS: Working age adults with asthma are at increased risk of IPI. In this population, approximately 5% of disease burden could be attributed to asthma. These findings support adding medicated asthma in adults to the list of indications for pneumococcal vaccination.

Seasonal patterns of viral and bacterial infections among children hospitalized with community-acquired pneumonia in a tropical region.

Community-acquired pneumonia (CAP) is a common cause of morbidity among children. Evidence on seasonality, especially on the frequency of viral and bacterial causative agents is scarce; such information may be useful in an era of changing climate conditions worldwide. To analyze the frequency of distinct infections, meteorological indicators and seasons in children hospitalized for CAP in Salvador, Brazil, nasopharyngeal aspirate and blood were collected from 184 patients aged < 5 y over a 21-month period. Fourteen microbes were investigated and 144 (78%) cases had the aetiology established. Significant differences were found in air temperature between spring and summer (p = 0.02) or winter (p < 0.001), summer and fall (p = 0.007) or winter (p < 0.001), fall and winter (p = 0.002), and on precipitation between spring and fall (p = 0.01). Correlations were found between: overall viral infections and relative humidity (p = 0.006; r = 0.6) or precipitation (p = 0.03; r = 0.5), parainfluenza and precipitation (p = 0.02; r = -0.5), respiratory syncytial virus (RSV) and air temperature (p = 0.048; r = -0.4) or precipitation (p = 0.045; r = 0.4), adenovirus and precipitation (p = 0.02; r = 0.5), pneumococcus and air temperature (p = 0.04; r = -0.4), and Chlamydia trachomatis and relative humidity (p = 0.02; r = -0.5). The frequency of parainfluenza infection was highest during spring (32.1%; p = 0.005) and that of RSV infection was highest in the fall (36.4%; p < 0.001). Correlations at regular strength were found between several microbes and meteorological indicators. Parainfluenza and RSV presented marked seasonal patterns.

Presence of capsular locus genes in immunochemically identified encapsulated and unencapsulated Streptococcus pneumoniae sputum isolates obtained from elderly patients with acute lower respiratory tract infection.

The principal virulence factor of Streptococcus pneumoniae is capsular polysaccharide, and encapsulated pneumococci are more common causes of disease than unencapsulated strains. This study analysed the presence of capsular genes in 59 pneumococcal isolates using two PCR methods targeted at the cpsA and cpsB genes of the capsular biosynthesis locus. The PCR method targeted at the cpsB gene, reported to be essential for encapsulation, was developed in this study. Of 59 pneumococcal isolates, 49 (83 %) were obtained from the sputum samples of elderly patients (≥65 years) with community-acquired pneumonia (CAP) and 10 (17 %) were from those with other acute lower respiratory tract infections (ARIs). Forty (82 %) of the CAP isolates and two (20 %) of the ARI isolates were encapsulated, as assessed by conventional immunochemical methods. Forty-one (98 %) of the 42 encapsulated strains had the cpsB gene present, and in 38 strains the cpsA gene was also detected. One of the unencapsulated isolates gave a positive result for the cpsB gene, and neither of the capsular locus genes were present in all the other unencapsulated strains. The distribution of encapsulated and unencapsulated isolates differed significantly between the two patient groups regardless of whether the presence of capsule was determined immunochemically (P<0.001) or by cpsB PCR (P=0.002). The cpsB PCR developed here was found to be a rapid and reliable method to detect the pneumococcal capsule locus and may have potential in sputum diagnostics when investigating the pneumococcal aetiology of CAP.

Rapamycin can inhibit the development of Chlamydia pneumoniae, which might partly contribute to the prevention of in-stent restenosis.

BACKGROUND: Rapamycin, an immunosuppressive and antiproliferative drug, is used to prevent neointima formation to reduce the risk of in-stent restenosis with rapamycin eluting-stents. Chronic infection of Chlamydia pneumoniae has been associated with cardiovascular diseases, and could play an important role in the mechanism of restenosis. We examined the effect of rapamycin on the growth of C. pneumoniae in cell cultures. METHODS: HL cell monolayers were inoculated with C. pneumoniae CWL029 or C. trachomatis L2. Different concentrations of rapamycin were present in the culture medium continuously or for 8-hour periods. After incubation the infected cells were repassaged to fresh HL cell monolayers and incubated in the medium without rapamycin. The newborn inclusions from both passages were checked by fluorescent microscope or electron microscope. RESULTS: The presence of 23 microg/ml rapamycin restricted over 90% of the growth of C. pneumoniae. Continuous presence of 11 microg/ml rapamycin inhibited the growth of C. pneumoniae up to 80% and caused smaller inclusions, fewer chlamydial particles and fewer matured EBs. 11 microg/ml rapamycin presented in first passage caused the reduction of C. pneumoniae to 57% at first passage and 24% at second passage. CONCLUSIONS: Sufficient rapamycin can inhibit the growth of C. pneumoniae effectively, but it should be applied at the early stage of the chlamydial infections. Rapamycin eluting-stents can induce a high enough local concentration of rapamycin. This provides a possibility for us to suppose that the beneficial effect of rapamycin in preventing in-stent restenosis might partly be explained by its inhibitory effects on the growth of C. pneumoniae.

Procalcitonin is useful in identifying bacteraemia among children with pneumonia.

Empirical antibiotic use is prescribed in managing children with pneumonia worldwide. We assessed the usefulness of procalcitonin (PCT) and interferon-alpha (IFN-alpha) in differentiating viral from bacterial pneumonia. Among 159 hospitalized children, pneumonia was diagnosed based on clinical complaints plus pulmonary infiltrate. Aetiology was investigated for 9 viruses and 4 atypical and 3 typical bacteria. PCT and IFN-alpha were measured in the serum sample collected on admission. Eight patients had bacteraemic infections, 38 had non-bacteraemic typical infections, and 19 patients had atypical bacterial infections. Viral and unknown aetiology was established in 57 (36%) and 34 (21%) cases, respectively. Three patients with bacterial infection without collected blood culture were excluded. IFN-alpha (IU/ml) was detectable in 20 (13%) cases. The difference among median PCT values of the bacteraemic (4.22; 1.56-7.56), non-bacteraemic typical bacterial (1.47; 0.24-4.07), atypical bacterial (0.18; 0.06-1.03) and only viral (0.65; 0.11-2.22) subgroups was significant (p = 0.02). PCT was > or =2 ng/ml in 52 (33%) cases. The presence of IFN-alpha was associated with PCT <2 ng/ml (90% vs. 64%, p = 0.02). The negative predictive value (95% confidence interval) of PCT > or =2 ng/ml was 95% (89-100%), 89% (78-100%), 93% (85-100%) for differentiation of bacteraemic from viral, atypical bacterial and non-bacteraemic typical bacterial infection, respectively, and 58% (49-68%) for differentiation between bacterial and viral infection. PCT may be useful in identifying bacteraemia among children hospitalized with community-acquired pneumonia. IFN-alpha was uncommonly detected.

Biofilm formation by Streptococcus pneumoniae isolates from paediatric patients.

The clinical significance of pneumococcal biofilm formation is largely unknown. To clarify this, we tested whether the ability of pneumococcal clinical isolates to form biofilm in vitro accounts for the diverse clinical outcomes. Clinical pneumococcal isolates were cultured from the nasopharynx (n=106), middle ear effusion (n=43) and blood (n=55) of 204 children altogether. Biofilm formation, assessed by measuring optical density (OD) values in microtitre plates after crystal violet staining, did not differ between the bacteria from different sources (p=0.18), the mean OD values of the isolates being 0.119 [95% confidence interval (CI) 0.100-0.138] in the nasopharynx samples, 0.094 (95% CI 0.069-0.119) in the acute otitis media cases, 0.109 (95% CI 0.077-0.141) in the secretory otitis media cases, 0.122 (95% CI 0.084-0.160) in those with sepsis and 0.175 (95% CI 0.071-0.280) in those with other invasive infections. Serotypes 33 and 14 were the most efficient in forming biofilms, whereas serotypes 3 and 38 were poor biofilm producers. We conclude that the clinical presentation of pneumococcal disease did not differ in relation to biofilm formation in vitro, even though there was marked variation between the clinical isolates and serotypes.

Diagnosis of Streptococcus pneumoniae and Haemophilus influenzae type b meningitis by identifying DNA from cerebrospinal fluid-impregnated filter paper strips.

BACKGROUND: Bacterial meningitis remains often etiologically unconfirmed, especially in resource-poor settings. We tested the potential of real-time polymerase chain reaction to identify Streptococcus pneumoniae (Pnc) and Haemophilus influenzae type b (Hib) from cerebrospinal fluid impregnated on filter paper strips. METHODS: Pnc and Hib genome equivalents were blindly quantified by polymerase chain reaction from 129 liquid cerebrospinal fluid (CSF) samples-the standard-and strips stored at room temperature for months. Genome counts were compared by simple regression. RESULTS: The strips showed a sensitivity and specificity of 92% and 99% for Pnc, and of 70% and 100% for Hib, respectively. The positive and negative predictive values were 94% and 97% for Pnc, and 100% and 89% for Hib, respectively. For Pnc, the positive and negative likelihood ratio was 92 and 0.08, and the overall accuracy 98%, whereas for Hib they were 70 and 0.30, and 91%, respectively. Genome counting showed good correlation between the filter paper and liquid CSF samples, r(2) being 0.87 for Pnc and 0.68 for Hib (P < 0.0001 for both). CONCLUSION: Although not replacing bacterial culture, filter paper strips offer an easy way to collect and store CSF samples for later bacteriology. They can also be transported in standard envelops by regular mail.

Quantification of Chlamydia pneumoniae in cultured human macrophages and HL cells: comparison of real-time PCR, immunofluorescence and ELISA methods.

Chlamydia pneumoniae is an intracellular gram-negative bacterium, which replicates only in eukaryotic cells. Quantification of C. pneumoniae in cell culture is needed when studying e.g. the effect of drugs or host cell factors on infectivity and replication. Conventionally, this has been performed by immunofluorescence staining and microscopic counting of chlamydial inclusions. However, this method is usable only if the cell numbers do not fluctuate in cell culture vials and the inclusions are uniform. In macrophages, inclusions are often aberrant, their sizes vary, and multiple inclusions are also seen. Therefore, methods are needed to quantify exact amounts of C. pneumoniae in cells. Here, we describe a new method based on the real-time PCR quantification of chlamydial genomes adjusted to the number of human genomes in cultures. In human epithelial (HL) cell cultures, the C. pneumoniae inclusion numbers and the ratio of C. pneumonia genomes/human genome (Cpn/Hum) correlated significantly (r = 0.978, p < 0.001); thus with HL cells, both methods are usable. However, in macrophage cultures, the correlation was weaker (r = 0.133, p = 0.036) and we recommend PCR quantification for exact measurements.