Lysinibacillus spp.: an IAA-producing endospore forming-bacteria that promotes plant growth

Lysinibacillus is a bacterial genus that has generated recent interest for its biotechnological potential in agriculture. Strains belonging to this group are recognized for their mosquitocidal and bioremediation activity. However, in recent years some reports indicate its importance as plant growth promoting rhizobacteria (PGPR). This research sought to provide evidence of the PGP activity of Lysinibacillus spp. and the role of the indole-3-acetic acid (IAA) production associated with this activity. Twelve Lysinibacillus spp. strains were evaluated under greenhouse conditions, six of which increased the biomass and root architecture of corn plants. In most cases, growth stimulation was evident at 10⁸ CFU/mL inoculum concentration. All strains produced IAA with high variation between them (20-70 µg/mL). The bioinformatic identification of predicted genes associated with IAA production allowed the detection of the indole pyruvic acid pathway to synthesize IAA in all strains; additionally, genes for a tryptamine pathway were detected in two strains. Extracellular filtrates from all strain's cultures increased the corn coleoptile length in an IAA-similar concentration pattern, which demonstrates the filtrates had an auxin-like effect on plant tissue. Five of the six strains that previously showed PGPR activity in corn also promoted the growth of Arabidopsis thaliana (col 0). These strains induced changes in root architecture of Arabidopsis mutant plants (aux1-7/axr4-2), the partial reversion of mutant phenotype indicated the role of IAA on plant growth. This work provided solid evidence of the association of Lysinibacillus spp. IAA production with their PGP activity, which constitutes a new approach for this genus. These elements contribute to the biotechnological exploration of this bacterial genus for agricultural biotechnology.

Lysinibacillus capsici sp. nov, isolated from the rhizosphere of a pepper plant

A strain of a Gram-positive, strictly aerobic, motile, rod-shaped, endospore forming bacterium was originally isolated from rhizospheric soil of a pepper plant when screening and bioprospecting for plant beneficial microorganisms. Phylogenetic analysis of the 16S rRNA gene sequences indicated that this strain, PB300^T, is closely related to Lysinibacillus macroides DMS 54^T (99.6%) and Lysinibacillus xylanilyticus DSM 23493^T (99.4%). In phenotypic characterisation, the novel strain was found to grow between 15 and 40 °C and tolerate up to 10% (w/v) NaCl. Furthermore, the strain was found to grow in media with pH 5 to 10 (optimal growth at pH 7.0). The predominant cellular fatty acids were observed to be iso-C_15 : 0 (56.6 %), anteiso-C_15 : 0 (14.6%), C_16 :1ω7C alcohol (9.3%) and C_16 : 0 (7.1%). The cell wall peptidoglycan contains lysine-aspartic acid, as in its close relatives. A draft genome was completed and the DNA G + C content was determined to be 37.5% (mol content). A phylogenomic analysis of the core genome of the new strain and 5 closely related type strains of the genus Lysinibacillus revealed that this strain formed a distinct monophyletic clade with the nearest neighbour being Lysinibacillus boronitolerans. DNA-DNA relatedness studies using in silico DNA-DNA hybridizations (DDH) showed relationships for the new strain were below the species threshold of 70%. Based upon the consensus of phylogenetic and phenotypic analyses, we conclude that this strain represents a novel species within the genus Lysinibacillus, for which the name Lysinibacillus capsici sp. nov. is proposed, with type strain PB300^T (= NRRL B-65515^T, = CCUG 72241^T).

[Short bowel syndrome in children: a diagnosis and management update]

Short bowel syndrome (SBS) refers to the sum of the functional alterations that are the result of a critical reduction in the length of the intestine, which in the absence of adequate treatment, presents as chronic diarrhea, chronic dehydration, malnutrition, weight loss, nutriment and electrolyte deficiency, along with a failure to grow that is present with greater frequency during the neonatal period. The aim was to carry out a review of the literature encompassing the definition and the most frequent causes of SBS, together with an understanding of its physiopathology, prognostic factors, and treatment. An Internet search of PubMed articles was carried out for the existing information published over the last 20 years on SBS in children, using the keywords "short bowel syndrome". From a total of 784 potential articles, 82 articles were chosen for the literature review. The treatment of patients presenting with SBS is quite a challenge and therefore it is necessary to establish multidisciplinary management with a focus on maintaining optimal nutritional support that covers the necessities of growth and development and at the same time provides a maximum reduction of short, medium, and long-term complications. The diagnosis and treatment of a child with SBS require a team of professionals that are experts in gastroenterologic, pediatric, and nutritional management. The outcome for the child will be directly related to opportune management, as well as to the length of the intestinal resection and the presence or absence of the ileocecal valve.

Antifungal prophylaxis with voriconazole or itraconazole in lung transplant recipients: hepatotoxicity and effectiveness

Invasive fungal infections (IFI) are common after lung transplantation and there are limited data for the use of antifungal prophylaxis in these patients. Our aim was to compare the safety and describe the effectiveness of universal prophylaxis with two azole regimens in lung transplant recipients. This is a retrospective study in lung transplant recipients from July 2003 to July 2006 who received antifungal prophylaxis with itraconazole or voriconazole plus inhaled amphotericin B to compare the incidence of hepatotoxicity. Secondary outcomes include describing the incidence of IFI, clinical outcomes after IFI and mortality. Sixty-seven consecutive lung transplants received antifungal prophylaxis, 32 itraconazole and 35 voriconazole and inhaled amphotericin B. There were no significant differences between groups in the acute physiology and chronic health evaluation (APACHE) score at the time of transplantation, demographic characteristics, comorbidities and concomitant use of hepatotoxic medications. Hepatotoxicity occurred in 12 patients receiving voriconazole and inhaled amphotericin B and in no patients receiving itraconazole (p < 0.001). There was no significant difference between groups with regard to the percentage of transplants with IFI, but one case of zygomycosis occurred in a transplant treated with voriconazole. Voriconazole prophylaxis after lung transplantation was associated with a higher incidence of hepatotoxicity and similar clinical effectiveness when compared to itraconazole.

Antibiotic cycling to decrease bacterial antibiotic resistance: a 5-year experience on a bone marrow transplant unit

Multidrug-resistant pathogens have important effects on clinical outcomes. Antibiotic cycling is one approach to control anti-microbial resistance, but few studies have examined cycling in hematology-oncology units. Antibiotic cycling was implemented in January 1999 at our hematology-oncology unit, alternating piperacillin-tazobactam (pip-tazo) and cefepime in 3 months periods, until June 2004. Clinical isolates were compared in post- and pre-intervention periods and with the susceptibility among the solid organ transplant intensive care unit (TICU) isolates. The rate of Gram-negative isolates remained stable. Among Gram-negatives, susceptibility to cefepime and pip-tazo remained stable. There was an increase in Enterococcus spp. (P=0.007), and susceptibility to ampicillin and vancomycin decreased (odds ratio (OR): 0.04, 95% confidence interval (CI): 0.17-0.89 and OR: 0.23, 95% CI: 0.09-0.58). Compared with the TICU, there was increased susceptibility to pip-tazo and cefepime among enterics (OR: 7.32, 95% CI: 4.44-12.07 and OR: 8.82, 95% CI: 2.1-37.13) and Pseudomonas aeruginosa (OR: 4.27, 95% CI: 1.47-12.4 and OR: 4.61, 95% CI: 1.75-12.1) and decreased susceptibility to ampicillin and vancomycin among enterococci (OR: 0.44, 95% CI: 0.30-0.63 and OR: 0.38, 95% CI: 0.26-0.56). Cycling was associated with preserved antibiotic susceptibility among Gram-negatives, but with an increase in Enterococcus spp. and vancomycin and ampicillin resistance among enterococci.

Analysis of IL1B, TAP1, TAP2 and IKBL polymorphisms on susceptibility to tuberculosis

Genetic determinants of human susceptibility to tuberculosis (TB) have not been completely elucidated. Interleukin-1 beta (IL-1beta) and the inhibitor of kB-like (IkBL) are important molecules that participate in the inflammatory response required for the immunological control of a broad spectrum of infectious agents. The transporter associated with antigen processing (TAP) is involved in the antigen processing via major histocompatibility complex class I molecules and in turn might regulate the T-cell response against Mycobacterium tuberculosis. To better characterize the host genetic factors determining the susceptibility to TB, we evaluated the influence of functional polymorphisms in IL1B, TAP and IKBL genes on the risk of developing pulmonary TB in a Northwestern Colombian population, an endemic area of M. tuberculosis infection. A total of 122 TB patients and 166 healthy controls (N = 166) negative for human immunodeficiency virus infection were examined for IL1B-511 and +3,953, TAP1 and TAP2 and IKBL+738 polymorphisms. Univariate analysis disclosed significant differences between patients and controls for IL1B+3,953 polymorphism. After unconditional logistic regression analysis, a strong protection conferred by IL1B+3,953 T-allele-carrying genotypes was observed. A trend between TAP2*0201 allele and disease was observed. Association between IL1B-511, TAP1 or IKBL polymorphisms and TB disease was not found. These results indicate that a functional polymorphism in the IL1B gene influences the susceptibility to TB and suggest a role for IL-1beta in the pathogenesis of mycobacterial infection.