Nasal immunization of mice with Lactobacillus casei expressing the Pneumococcal Surface Protein A: induction of antibodies, complement deposition and partial protection against Streptococcus pneumoniae challenge

Strategies for the development of new vaccines against Streptococcus pneumoniae infections try to overcome problems such as serotype coverage and high costs, present in currently available vaccines. Formulations based on protein candidates that can induce protection in animal models have been pointed as good alternatives. Among them, the Pneumococcal Surface Protein A (PspA) plays an important role during systemic infection at least in part through the inhibition of complement deposition on the pneumococcal surface, a mechanism of evasion from the immune system. Antigen delivery systems based on live recombinant lactic acid bacteria (LAB) represents a promising strategy for mucosal vaccination, since they are generally regarded as safe bacteria able to elicit both systemic and mucosal immune responses. In this work, the N-terminal region of clade I PspA was constitutively expressed in Lactobacillus casei and the recombinant bacteria was tested as a mucosal vaccine in mice. Nasal immunization with L. casei-PspA 1 induced anti-PspA antibodies that were able to bind to pneumococcal strains carrying both clade 1 and clade 2 PspAs and to induce complement deposition on the surface of the bacteria. In addition, an increase in survival of immunized mice after a systemic challenge with a virulent pneumococcal strain was observed. (C) 2008 Elsevier Masson SAS. All rights reserved.

Radiographic Findings Among Children Hospitalized With Severe Community-Acquired Pneumonia

Background: Community-acquired pneumonia (CAP) is a leading cause of childhood death. There are few published reports of radiographic findings among children with severe CAP. Objective: To describe chest X-ray (CXR) findings and assess association between these radiographic findings and pneumococcal isolation in children with severe CAP. Methods: A prospective, multicenter, observational study was conducted in 12 centers in Argentina, Brazil, and the Dominican Republic. Children aged 3-59 months, hospitalized with severe pneumonia, were included. On admission, blood and pleural effusion cultures were performed. Streptococcus pneumoniae was identified according to standard procedures in the respective national reference laboratory. Chest X-rays were taken on admission and read before the culture results were reported. Results: Out of 2,536 enrolled patients, 283 (11.2%) had S. pneumoniae isolated, in 181 cases (7.1%) from blood. The follow radiographic patterns were observed: alveolar infiltrate (75.2%), pleural effusion (15.6%), and interstitial infiltrate (9.2%). Overall, pleural effusion was associated with pneumococcal isolation and pneumococcal bacteremia (P < 0.001). Infiltrates were unilateral (78.7%) or bilateral (21.3%), right-sided (76%) or left-sided (24%), in the lower lobe (53.6%) or the upper lobe (46.4%). Multivariate analysis including patients with affection of only one lobe showed that upper lobe affection and pleural effusion were associated with pneumococcal isolation (OR 1.8, 95% CI, 1.3-2.7; OR 11.0, 95% CI, 4.6-26.8, respectively) and with pneumococcal bacteremia (OR 1.7, 95% CI, 1.2-2.6; OR 3.1, 95% CI, 1.2-8.0, respectively). Conclusions: Three-quarters of the patients studied had alveolar infiltrates. Upper lobe compromising and pleural effusion were associated with pneumococcal invasive disease. Pediatr Pulmonol. 2010; 45:1009-1013. (C) 2010 Wiley-Liss, Inc.

The role of respiratory viral infections among children hospitalized for community-acquired pneumonia in a developing country

We report an investigation for 16 bacteria and viruses among 184 children hospitalized with pneumonia in Salvador, Brazil. Etiology was established in 144 (78%) cases. Viral, bacterial, and mixed infections were found in 110 (60%), 77 (42%), and 52 (28%) patients, respectively. Rhinovirus (21%) and Streptococcus pneumoniae (21%) were the most common pathogens. Our results demonstrate the importance of viral and pneumococcal infections among those patients.

Ohr (Organic Hydroperoxide Resistance Protein) Possesses a Previously Undescribed Activity, Lipoyl-dependent Peroxidase

The Ohr (organic hydroperoxide resistance) family of 15-kDa Cys-based, thiol-dependent peroxidases is central to the bacterial response to stress induced by organic hydroperoxides but not by hydrogen peroxide. Ohr has a unique three-dimensional structure and requires dithiols, but not monothiols, to support its activity. However, the physiological reducing system of Ohr has not yet been identified. Here we show that lipoylated enzymes present in the bacterial extracts of Xylella fastidiosa interacted physically and functionally with this Cys-based peroxidase, whereas thioredoxin and glutathione systems failed to support Ohr peroxidase activity. Furthermore, we could reconstitute in vitro three lipoyl-dependent systems as the Ohr physiological reducing systems. We also showed that OsmC from Escherichia coli, an orthologue of Ohr from Xylella fastidiosa, is specifically reduced by lipoyl-dependent systems. These results represent the first description of a Cys-based peroxidase that is directly reduced by lipoylated enzymes.

Transfer of antibodies across the placenta and in breast milk from mothers on intravenous immunoglobulin

We studied the levels of immunoglobulins in colostrum, milk and sera from two common variable immunodeficiency (CVID) mothers (M1 and M2), and in sera from their newborn infants. During pregnancy they continued intravenous immunoglobulin therapy (IVIG). Antibody levels from maternal and cord blood collected at delivery and colostrum and milk, collected on the 3rd and 7th post-partum days, respectively, were analyzed. Although cord/maternal blood ratios of total immunoglobulins and subclasses, as well as specific antibodies differed between M1 and M2, both showed good placental transfer of anti-protein and anti-polysaccharide antibodies, despite lower cord/maternal blood ratios in M2. Anti-Streptococcus pneumoniae antibody avidity indexes were similar between paired maternal and cord serum. Both mothers` colostrum and milk samples showed only traces of IgA, and IgM and IgG levels in colostrum were within normal range in M1, whereas M2 presented elevated IgG and low IgM levels, when compared with healthy mothers. The study of colostrum and milk activity showed that they strongly inhibited enteropathogenic Escherichia coli adhesion in vitro. CVID patients must be informed about the relevance of regular IVIG administration during pregnancy, not only for their own health but also for their immune immature offspring. Breast-feeding should be encouraged as colostra from these CVID patients strongly inhibited E. coli adhesion to human epithelial cells thus providing immunological protection plus nutritional and psychological benefits for the infant.

The Challenges of Antimicrobial Resistance in Brazil

Brazil is a country with continental proportions with high geographic and economic diversity. Despite its medical centers of excellence, antimicrobial resistance poses a major therapeutic challenge. Rates of methicillin-resistant Staphylococcus aureus are up to 60% and are related to an endemic Brazilian clone. Local resistance to vancomycin in Enterococci was first related to Enterococcus faecalis, which differs from European and American epidemiology. Also, local Klebsiella pneumoniae and Escherichia coli isolates producing extended-spectrum beta-lactamases have a much higher prevalence (40%-50% and 10%-18%, respectively). Carbapenem resistance among the enterobacteriaceae group is becoming a major problem, and K. pneumoniae carbapenemase isolates have been reported in different states. Among nonfermenters, carbapenem resistance is strongly related to SPM-1 (Pseudomonasaeruginosa) and OXA-23 (Acinetobacter baumannii complex) enzymes, and a colistin-only susceptible phenotype has also emerged in these isolates, which is worrisome. Local actions without loosing the global resistance perspective will demand multidisciplinary actions, new policies, and political engagement.

Emergence of Klebsiella pneumoniae carrying the novel extended-spectrum beta-lactamase gene variants bla(SHV-40), bla(TEM-116) and the class 1 integron-associated bla(GES-7) in Brazil

A clinical Klebsiella pneumoniae isolate carrying the extended-spectrum beta-lactamase gene variants bla(SHV-40), bla(TEM-116) and bla(GES-7) was recovered. Cefoxitin and ceftazidime activity was most affected by the presence of these genes and an additional resistance to trimethoprim-sulphamethoxazole was observed. The bla(GES-7) gene was found to be inserted into a class 1 integron. These results show the emergence of novel bla(TEM) and bla(SHV) genes in Brazil. Moreover, the presence of class 1 integrons suggests a great potential for dissemination of bla(GES) genes into diverse nosocomial pathogens. Indeed, the bla(GES-7) gene was originally discovered in Enterobacter cloacae in Greece and, to our knowledge, has not been reported elsewhere.

Septic Shock, Necrotizing Pneumonitis, and Meningoencephalitis Caused by Mycoplasma pneumoniae in a Child: A Case Report

Mycoplasma pneumoniae is an important causative agent of respiratory infection in childhood. Although the infection caused by M. pneumoniae is classically described as benign, severe and life-threatening pulmonary and extrapulmonary complications can occur. This study describes the first case of septic shock related to M. pneumoniae in a child with necrotizing pneumonitis, severe encephalitis, and multiple organs involvement, with a favorable outcome after lobectomy and systemic corticosteroids

Induction of neutralizing antibodies in mice immunized with an amino-terminal polypeptide of Streptococcus mutans P1 protein produced by a recombinant Bacillus subtilis strain

The oral pathogen Streptococcus mutans expresses a surface protein, P1, which interacts with the salivary pellicle on the tooth surface or with fluid-phase saliva, resulting in bacterial adhesion or aggregation, respectively. P1 is a target of protective immunity. Its N-terminal region has been associated with adhesion and aggregation functions and contains epitopes recognized by efficacious antibodies. In this study, we used Bacillus subtilis, a gram-positive expression host, to produce a recombinant N-terminal polypeptide of P1 (P1(39-512)) derived from the S. mutans strain UA159. Purified P1(39-512) reacted with an anti-full-length P1 antiserum as well as one raised against intact S. mutans cells, indicating preserved antigenicity. Immunization of mice with soluble and heat-denatured P1(39-512) induced antibodies that reacted specifically with native P1 on the surface of S. mutans cells. The anti-P1(39-512) antiserum was as effective at blocking saliva-mediated aggregation of S. mutans cells and better at blocking bacterial adhesion to saliva-coated plastic surfaces compared with the anti-full-length P1 antiserum. In addition, adsorption of the anti-P1 antiserum with P1(39-512) eliminated its ability to block the adhesion of S. mutans cells to abiotic surfaces. The present results indicate that P1(39-512), expressed and purified from a recombinant B. subtilis strain, maintains important immunological features of the native protein and represents an additional tool for the development of anticaries vaccines.

Risk factors for colonisation of newborn infants during an outbreak of extended-spectrum beta-lactamase-producing Klebsiella pneumoniae in an intermediate-risk neonatal unit

We describe a cross-sectional, survey to identify risk factors for colonisation of neonates by extended-spectrum P-Lactamase (ESBL)-producing Klebsiella pneumoniae. This occurred following exposure to a colonised healthcare worker during an outbreak in an intermediate-risk neonatal. unit. In total, 120 neonates admitted consecutively during a three-month period were screened for ESBL-producing K. pneumoniae by rectal swabbing and 27 were identified as colonised. Multivariate analysis showed colonisation to be independently associated with use of antibiotics and absence of breastfeeding. Previous use of antibiotics presented an odds ratio (OR) of 12.3 [95% confidence interval. (Cl): 3.66-41.2, P < 0.001]. The most commonly used antibiotics were penicillin and amikacin. Breastfeeding was associated with reduced risk for colonisation (OR: 0.22; 95% Cl: 0.05-0.99; P = 0.049). Nine isotates recovered during the first stage of the outbreak and 27 isolates from surveillance cultures were typed thereafter by pulsed-field gel electrophoresis, revealing six different profiles (A-F). Clones A, C, and E were implicated in the first stage of the outbreak, whereas among the 27 strains recovered from surveillance cultures, all six clones were identified. Clone A was also found on the hand of a nursing auxiliary with onychomycosis. We concluded that prior antimicrobial use predisposed to colonisation. The possible role of breastfeeding as a protective factor needs to be further elucidated. Detection of different genotypes of ESBL-producing K. pneumonioe suggests that dissemination of mobile genetic elements bearing the ESBL gene may have been superimposed on the simple dissemination of a clone during the outbreak. (c) 2008 The Hospital Infection Society. Published by Elsevier Ltd. All rights reserved.