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Invasive Infections (invasive + infections)

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Medical Sciences	100%

Selected Abstracts

In vitro response to Candida albicans in cultures of whole human blood from young and aged donors

FEMS IMMUNOLOGY & MEDICAL MICROBIOLOGY, Issue 2 2007
Celia Murciano
Abstract Invasive infections with opportunistic fungi, such as Candida albicans, have become an increasing problem in aged adults in recent years. This work investigates the influence of human ageing on C. albicans recognition by toll-like receptors (TLRs), essential components of the innate immune system, using a cohort of 96 young (15,42 years) and aged (>70 years) human volunteers. No significant differences between aged and young donors were observed on (1) cell surface TLR2, TLR6 and TLR4 expression on lymphocytes, monocytes and granulocytes, (2) production of cytokines [IL-8, IL-1,, IL-6, IL-10, tumour necrosis factor (TNF)-, and IL-12p70] and prostaglandin E2 (PGE2) by whole human blood in response to C. albicans and (3) fungicidal activity of whole blood. A statistically significant higher titre of natural anti- C. albicans antibodies was found in plasma of volunteers between 80 and 95 years old when compared with other age groups, probably as a consequence of the increased levels of serum Ig that has been described in elderly subjects. Therefore, the results indicate that the increased susceptibility to C. albicans infections in the elderly is not a consequence of defects in TLRs expression or signalling, nor of an impaired fungicidal activity of blood. [source]

Invasive infections caused by Neisseria meningitidis, Haemophilus influenzae and Streptococcus pneumoniae among children in St Petersburg, Russia

CLINICAL MICROBIOLOGY AND INFECTION, Issue 5 2008
T. Kaijalainen
Abstract This study investigated the causes of invasive bacterial infections in children aged <15 years in St Petersburg, Russia, during 2001,2003, using culture and antigen detection methods (rapid antigen latex agglutination (RAL)) for normally sterile body fluids. A pathogen was detected in 90 cases (culture 50, RAL 40). Neisseria meningitidis was the most common pathogen (66%), followed by Haemophilus influenzae (19%) and Streptococcus pneumoniae (16%). Meningitis was the main clinical diagnosis (68/90, 76%), with N. meningitidis serogroup B, H. influenzae type b (Hib), and S. pneumoniae serogroup 1 being the most common isolates. Hib was less prevalent in St Petersburg than it was in industrialised countries before the introduction of Hib vaccinations. [source]

Invasive group A, B, C and G streptococcal infections in Denmark 1999,2002: epidemiological and clinical aspects

CLINICAL MICROBIOLOGY AND INFECTION, Issue 7 2005
K. Ekelund
Abstract Group A streptococci (GAS) have been described frequently as an emerging cause of severe invasive infections in population-based surveillance studies, whereas the descriptions of group B, C and G streptococci (GBS, GCS and GGS) have been less frequent. Enhanced surveillance for invasive GAS, GBS, GCS and GGS was performed in Denmark in 1999,2002. A detailed questionnaire was completed for 1237 (98%) of 1260 invasive infections. GAS infections dominated (40%), followed by GGS (32%), GBS (23%) and GCS (6%). Most (74%) patients had predisposing factors, and there were no significant differences between the four serogroups when comparing the prevalence of cancer, diabetes mellitus, chronic heart or lung diseases, immunodeficiency or alcohol abuse. The overall case fatality rate at day 30 was 21%, increasing significantly to 59% for patients with streptococcal toxic shock syndrome (STSS). STSS was significantly more frequent in GAS patients (10%) than in GCS (4%), GBS (2%) and GGS (2%) patients. Regression analyses showed that, despite a younger median age among GAS patients, the probability of developing septic shock and mortality was significantly higher among GAS patients than among GBS and GGS patients. These analyses showed no significant differences between GAS and GCS infections. Invasive infections caused by GAS, GBS, GCS and GGS are still a major challenge for clinicians. Continued epidemiological and microbiological surveillance is important to assess the development of these infections and to improve preventative strategies. [source]

Epidemiology of invasive pneumococcal infections in children aged 0,6 years in Denmark: a 19-year nationwide surveillance study

ACTA PAEDIATRICA, Issue 2000
MS Kaltoft
The impact of the new pneumococcal conjugate vaccines on invasive disease burden in Danish children was evaluated by analysing the results from the last 19 years of a nationwide surveillance of invasive pneumococcal infections. During 1981,1999, the Streptococcus Unit at Statens Serum Institut, Copenhagen, received 1123 invasive pneumococcal isolates from children aged 0,6 years. Nearly 72% (71.8%) of the pneumococcal isolates were from children aged <2 y. The median ages of children with pneumococcal meningitis and bacteraemia were 10.2 mo and 15.9 mo, respectively. The incidence of pneumococcal meningitis remained stable during the study period. The mean annual incidence rates of pneumococcal meningitis among children aged <1, <2, and <7 years were 17.4, 12.4, and 4.3 per 100000, respectively, during 1981,1999 (overlapping age groups are used throughout this article to facilitate the comparison of incidence data from different countries or among different studies). The annual incidence of pneumococcal bacteraemia increased from 1981 to 1996, after which a slight fall was noted. During the last six years of the study period, the mean annual incidence rates of bacteraemia were 30.1, 32.5, and 14.0 per 100000 children aged <1, <2, and <7 years. In the 1990s, pneumococcal isolates with reduced sensitivity to penicillin (0,5% each year) and erythromycin (7.4% in 1999) emerged as a cause of invasive infections in children aged 0,6 years in Denmark. During 1981,1999, 10 serotypes (1, 4, 6A, 6B, 7F, 9V, 14, 18C, 19F, 23F) caused 82% of invasive infections in Danish children. Importantly, no significant temporal changes in overall serotype distribution or differences in serotype distributions between girls and boys could be documented during the study period. Conclusion: According to the Kaiser Permanente trial, the 7-, 9-, and 11-valent pneumococcal conjugate vaccines will probably cover around 60%, 70%, and 80%, respectively, of all invasive pneumococcal infections in Danish children aged 0,6 y, corresponding to 12,14 episodes of meningitis and 40,60 episodes of bacteraemia per year. [source]

Recruitment and selection of marginal zone B,cells is independent of exogenous antigens

EUROPEAN JOURNAL OF IMMUNOLOGY, Issue 7 2005
Peter
Abstract Marginal zone B (MZ-B) cells of the spleen contribute significantly to the immunity against invasive infections with polysaccharide-encapsulated bacteria. Recent evidence indicates that recruitment and selection of MZ-B,cells occurs on the basis of positive selection constraints that likely operate via B,cell receptor (BCR) signaling. Previous studies have shown that MZ-B,cells carry relatively shorter immunoglobulin (Ig) heavy (H) chain complementarity-determining region,3 (H-CDR3) sequences and express BCR which are thought to be polyreactive. In this scenario, MZ-B,cell selection proceeds via engagement of the BCR with exogenous (i.e. microbial gut flora-derived) and/or endogenous (self) antigens. Here, we studied the influence of exogenous antigens on the selection process of MZ-B,cells using non-genetically manipulated adult germ-free and conventionally reared infant rats. This study was carried out by H-CDR3 spectratype analysis of VH(PC7183)-encoded Ig VHDJH -, transcripts expressed by purified splenic MZ-B,cells and other B,cell subsets. We show that MZ-B,cells in both adult germ-free and conventionally reared infant (14-day-old) rats are H-CDR3-selected cells, providing strong evidence that recruitment and selection of MZ-B,cells is driven by self antigens. [source]

Minireview: Malassezia infections in immunocompromised patients

MYCOSES, Issue 3 2010
Athanasios Tragiannidis
Summary Malassezia spp. form part of the normal human cutaneous flora and are implicated in several mild, but recurrent cutaneous diseases, such as pityriasis versicolor, Malassezia folliculitis, seborrhoeic dermatitis, and, with lesser frequency, a range of other dermatological disorders. Malassezia spp. have also been associated with cutaneous and systemic diseases in immunocompromised patients including folliculitis, seborrhoeic dermatitis, catheter-related fungaemia and a variety of deeply invasive infections. In this review, we provide an overview of the epidemiology, risk factors, pathogenesis, clinical manifestations, diagnosis, treatment and outcome of cutaneous and invasive Malassezia infections in immunocompromised patients. [source]

Biofilm formation by Streptococcus pneumoniae isolates from paediatric patients

APMIS, Issue 4 2010
TERHI TAPIAINEN
Tapiainen T, Kujala T, Kaijalainen T, Ikäheimo I, Saukkoriipi A, Renko M, Salo J, Leinonen M, Uhari M. Biofilm formation by Streptococcus pneumoniae isolates from paediatric patients. APMIS 2010; 118: 255,60. 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. [source]

Community-associated Staphylococcus aureus infections and nasal carriage among children: molecular microbial data and clinical characteristics

CLINICAL MICROBIOLOGY AND INFECTION, Issue 11 2008
G. Sdougkos
Abstract An increasing number of infections caused by community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) carrying the Panton,Valentine leukocidin (PVL) genes was recently identified in Greece. In the present study, 170 patients with S. aureus infections and 123 uninfected children (<15 years old) who had been tested for nasal carriage were evaluated during a 2-year period. The MecA, PVL and superantigen family genes, and MRSA clones, were investigated by molecular methods. Sites of infection and laboratory findings for patients were recorded. The results were compared and statistically analysed. Among 123 uninfected children 73 (59%) carried S. aureus, including four MRSA strains. Of these, three MRSA and three methicillin-sensitive S. aureus (MSSA) strains were PVL-positive (p <0.0001). Ninety-six patients (96/170) exhibited skin and soft-tissue infections (SSTIs), and 74 exhibited invasive infections. The incidence of staphylococcal infections increased during July to September each year. In total, 110 S. aureus isolates were PVL-positive (81 from SSTIs and 29 from invasive infections, p <0.0001). Ninety-nine out of 106 MRSA (93%) isolates from 170 patients carried the PVL genes (p <0.0001); 97 belonged to the clonal complex CC80. Leukocyte and polymorphonuclear cell counts were higher among children with MRSA infections (p <0.005). MSSA predominated among patients with invasive infections (43/74), and carried mainly genes of the superantigen family. Children <5 years of age showed a higher risk of MRSA infection. The present study demonstrates that infections due to PVL-positive CA-MRSA spread easily among children, and SSTIs can lead to invasive infections. Nasal colonization may be an additional factor contributing to the emergence of CA-MRSA. [source]

Serotypes and antimicrobial susceptibilities of 1033 pneumococci isolated from children in Greece during 2001,2004

CLINICAL MICROBIOLOGY AND INFECTION, Issue 5 2006
I. Paraskakis
Abstract Pneumococci (n = 1033) isolated in the major paediatric hospitals of Athens during 2001,2004 from children with invasive infections (n = 186), non-invasive infections (n = 641) and healthy carriers (n = 206) were studied. The most prevalent serotypes were serotypes 14 (44.6%), 19F (43.5%) and 6B (22.8%) in invasive, non-invasive and carriage isolates, respectively. Among invasive isolates, the potential coverage by the seven-valent conjugate vaccine was 75.3%. Resistance rates to penicillin, amoxycillin, cefotaxime, erythromycin, co-trimoxazole, clindamycin, tetracycline and chloramphenicol were 44.6%, 2.7%, 1.2%, 43.6%, 43.5%, 12.4%, 34.7% and 5.9%, respectively. The M-phenotype accounted for 68.0% of the erythromycin-resistant isolates. All isolates were susceptible to ofloxacin. [source]

Nationwide study of recurrent invasive pneumococcal infections in a population with a low prevalence of human immunodeficiency virus infection

CLINICAL MICROBIOLOGY AND INFECTION, Issue 9 2005
H. M. Einarsdóttir
Abstract Recurrent invasive infections caused by Streptococcus pneumoniae are rare, and often considered to be indicative of serious underlying illness. However, the prevalence of this problem, and the relevance of specific predisposing conditions, can be hard to assess, since many of the studies are based on specific risk groups. A population-based study of recurrent invasive pneumococcal disease in Iceland during the 30-year period 1975,2004 was performed. Clinical information, including mortality and vaccine use, was analysed retrospectively. Invasive pneumococcal isolates were serotyped and susceptibility testing was performed. During this period, 36 (4.4%) of 819 patients who survived an initial infection experienced recurrence, with a median time between episodes of 9.7 months. Pneumonia with bacteraemia was the most common clinical diagnosis (48% of cases), followed by bacteraemia without a clear focus (21%) and meningitis (13%). Most (94%) of the patients had identifiable predisposing conditions, most commonly, multiple myeloma in adults, and antibody deficiencies in children. Compared with children, adults were more likely to present with pneumonia (65% vs. 18%; p 0.0001). No significant change in the 30-day mortality rate was observed during the three decades of the study. Only 26% of eligible patients received pneumococcal vaccination. Patients with recurrent invasive pneumococcal disease should be investigated thoroughly for underlying diseases. Greater use of pneumococcal vaccines should be encouraged among high-risk patients. More effective preventive and therapeutic measures are needed to improve outcomes. [source]