Chemokine Patterns in Children with Acute Bacterial Infections.

Chemokines are chemotactic cytokines that are mainly involved in the migratory patterns of immune cells. Few studies have evaluated the levels of chemokines in children with acute bacterial infections. The aim of this study was to evaluate the serum levels of chemokines MCP-1, RANTES, MIG and IP-10 in children with sepsis, community-acquired pneumonia (CAP) and skin abscess. Serum levels of MCP-1, RANTES, MIG and IP-10 were measured in 37 children with sepsis, 27 children with CAP, 25 children with skin abscess and 20 controls with no signs of infection. Patients with sepsis, CAP and skin abscess had higher concentrations of RANTES compared to controls (P = 0.0057, P = 0.0004 and P = 0.0108, respectively). IP-10 values were higher in patients with sepsis compared to children with skin abscess (P = 0.0075). However, MCP-1 levels were lower in septic patients compared to controls (P = 0.0136). There was no difference on MIG concentrations between the groups. Our original findings observed that RANTES was consistently elevated in all types of infections suggesting this chemokine may play an important role in the pathogenesis of bacterial infection. Additionally, patients with sepsis had a unique pattern of response with high levels of IP-10 but low levels of MCP-1, which should be further explored as the markers of disease severity.

Respiratory syncytial virus infection of airway epithelial cells, in vivo and in vitro, supports pulmonary antibody responses by inducing expression of the B cell differentiation factor BAFF.

BACKGROUND: The mechanisms regulating antibody expression within the human lung during airway infection are largely unknown. In this study, our objectives were to determine if infection with respiratory syncytial virus (RSV) upregulates expression of the B cell differentiation factors A proliferation inducing ligand (APRIL) and B cell activating factor of the TNF family (BAFF), if this is a common feature of viral airway infection, and how this is regulated in human airway epithelial cells. METHODS: We measured BAFF and APRIL protein expression in bronchoalveolar lavage (BAL) fluid from infants with severe RSV disease, and healthy control children, and in nasopharyngeal aspirates from preschool children with other single respiratory viral infections. We also measured mRNA expression in bronchial brushings from RSV-infected infants, and in RSV-infected paediatric primary airway epithelial cell cultures (pAEC). Beas-2B cell cultures were used to examine mechanisms regulating BAFF expression. RESULTS: BAFF protein and mRNA were elevated (in marked contrast with APRIL) in BAL and bronchial brushings, respectively, from RSV-infected infants. BAFF protein was also found in upper airway secretions from children with human metapneumovirus, H1N1, bocavirus, rhinovirus, RSV and Mycoplasma pneumoniae infection. BAFF mRNA and protein were expressed following in vitro RSV infection of both pAEC and Beas-2B cultures, with mRNA expression peaking 12-h postinfection. BAFF induction was blocked by addition of a neutralising anti-interferon-ß antibody or palivizumab. CONCLUSIONS: BAFF, produced through an interferon-ß-dependent process, is a consistent feature of airway infection, and suggests a role for the airway epithelia in supporting protective antibody and B cell responses in the lung.

Colonisation by extended-spectrum beta-lactamase-producing Klebsiella spp. in a paediatric intensive care unit.

A prospective cohort study was performed in order to study the incidence and risk factors for bacterial colonisation with extended-spectrum producing beta-lactamase (ESBL) Klebsiella spp. in children. The study took place in a paediatric intensive care unit (PICU) in Recife, Brazil over a five-month period in 2008. Rectal swabs were collected during the first 24h of admission and on the 2nd, 5th, 7th and 14th days of PICU stay. ESBL-producing strains of Klebsiella spp. were detected by Kirby-Bauer disc diffusion and confirmed by double disc synergy testing. A total of 186 children were enrolled with a median age of three years. The overall colonisation rate with ESBL-producing Klebsiella spp. was 14%, but 13 (7%) children were already colonised upon admission. The incidence density of colonisation during PICU admission was 14.2 per 1000 patient-days. On multivariable analysis, the use of third generation cephalosporins (P=0.008) was a risk factor for colonisation. Survival analysis revealed an increase in the accumulated risk of colonisation with an increase in length of stay in the PICU. The present study provides baseline information to guide improved practices in similar settings and direct future studies in relation to the magnitude of cross-infection and effectiveness of infection control interventions.

Norovirus infection among children with acute gastroenteritis in Recife, Brazil: disease severity is comparable to rotavirus gastroenteritis.

Norovirus has captured increasing attention as an agent of childhood diarrhoea. However, it is not known whether norovirus causes as severe diarrhoea as rotavirus, particularly among children in developing countries. In a 1-year study conducted between May 2004 and April 2005 in Recife, Brazil, norovirus was detected by ELISA in 34/233 (15%) diarrhoeal children less than 5 years of age. The severity of clinical illness, as indicated by the presence of dehydration, the requirement for hospitalization, and the duration of hospital stay, was similar between children with norovirus and rotavirus infection. These data underscore the importance of norovirus as a cause of severe diarrhoea in children.

Apparent extinction of non-G2 rotavirus strains from circulation in Recife, Brazil, after the introduction of rotavirus vaccine.

The introduction of a G1P[8] rotavirus vaccine in Recife, Brazil, caused a decrease in rotavirus detection from 27% (March-May, 2006) to 5.0% (March-May, 2007), with all strains becoming G2, against which less protection had been predicted.

Comparison of urine contamination rates using three different methods of collection: clean-catch, cotton wool pad and urine bag.

Collecting uncontaminated urine specimens from infants is difficult. Commonly, an adhesive urinecollecting bag is used, which is uncomfortable. This study determined bacterial contamination rates using three methods of urine collection sequentially on the same infant (without known urinary tract infection)-clean-catch, cotton wool (sanitary) pad and urine bag. The study was undertaken in children under 3 years of age in the Institute of Maternal and Child Health of Pernambuco (IMIP), Recife, Brazil. Urine samples were analysed using phase contrast microscopy and routine culture. Culture of bacteria at any level was interpreted as a contaminated urine specimen. Cultures with > 10(5) colony-forming units/ml of one species by all three collection methods were regarded as true urinary tract infection and these children were excluded. Altogether, 534 urine samples from 191 patients were analysed. Median age was 2 months (1 day-36 months) and 124 (65%) were boys. Twelve children (6.3%) were considered to have true urinary tract infection, three were indeterminate and in 16 one or more samples were missing and all were excluded from analysis. There were more missing samples using the clean-catch method (12%) than when using the bag (4%) or pad (4%). Seventy-six of 160 (47.5%) children had evidence of bacterial contamination. Clean-catch specimens showed the least contamination (14.7%) and rates were similar between pads (29%) and bags (26.6%) (kappa = 0.40). Urine contamination rates were similar for sanitary pads and urine bags and significantly higher than for clean-catch (p<0.01). However, pads were a simple, non-invasive and comfortable alternative to bags.