Adaptive response of single and binary Pseudomonas aeruginosa and Escherichia coli biofilms to benzalkonium chloride

The main goal of this work was to examine whether the continuous exposure of single and binary P. aeruginosa and E. coli biofilms to sub-lethal benzalkonium chloride (BC) doses can induce adaptive response of bacteria. Biofilms were formed during 24 h and then put continuously in contact with BC for more 5 days. The six-day-old adapted biofilms were then submitted to BC challenge, characterized and inspected by SEM. Both single and binary adapted biofilms have clearly more biomass, polysaccharides and proteins and less activity even though the number of cells was identical. After BC treatment, adapted biofilms maintained their mass and activity. SEM examination revealed that those adapted biofilms had a slimier and denser matrix that became thicker after BC treatment. Continuous exposure of bacteria to antimicrobials can lead to development of biofilms encompassing more virulent and tolerant bacteria. This adaptive resistance can be the result of a phenotypic adaptation, a genetic acquired resistance or both. Instead of eradicating biofilms and kill microorganisms, the use of a disinfectant can, favour biofilm formation and tolerance. This must be a genuine concern as it can happen in clinical environments, where the use of antimicrobials is unavoidable.     

Phage endolysins with broad antimicrobial activity against Enterococcus faecalis clinical strains

Increasing antibiotic resistance of bacterial pathogens has drawn the attention to the potential use of bacteriophage endolysins as alternative antibacterial agents. Here we have identified, characterized, and studied the lytic potential of two endolysins, Lys168 and Lys170, from phages infecting Enterococcus faecalis. Lys168 and Lys170 belong to the cysteine, histidine-dependent amidohydrolases/peptidases (CHAP) and amidase-2 protein families, respectively. Lys168 is quite a unique enterococcal phage endolysin. It shares 95% amino acidic identity with the endolysin of Staphylococcus aureus phage SAP6, which in turn is distantly related to all known CHAP endolysins of S. aureus phages. Lys170 seems to be a natural chimera assembling catalytic and cell-wall-binding domains of different origin. Both endolysins showed a clear preference to act against E. faecalis and they were able to lyse a high proportion of clinical isolates of this species. Specifically, Lys168 and Lys170 lysed more than 70% and 90% of the tested isolates, respectively, which included a panel of diverse and typed strains representative of highly prevalent clonal complexes. Lys170 was active against all tested E. faecalis VRE strains. The quasi specificity toward E. faecalis is discussed considering the nature of the enzymes' functional domains and the structure of the cell wall peptidoglycan.     

Severe phenotype in MPS II patients associated with a large deletion including contiguous genes

Hunter disease or mucopolysaccharidosis type II (MPS II) is an X-linked recessive lysosomal disorder caused by the deficiency of iduronate-2-sulfatase, which is involved in the catabolism of the glycosaminoglycans (GAGs) heparan and dermatan sulphate. Our aim was to analyze three patients with severe Hunter syndrome that showed a total deletion of the iduronate-2-sulphatase (IDS) gene, after exon by exon PCR. DNA was used as a template for PCR synthesis of IDS, FRAXA, FRAXE, and DXS1113 specific amplicons. The DNA analysis for all three patients demonstrated a complete deletion of IDS, FRAXA, and FRAXE contiguous genes. We further performed SNP-array to delineate the deletion breakpoints and to characterize the deletion extension in the different patients. The results indicated a ～9.4 Mb deletion in Patient 1, a ～3.9 Mb deletion of the Xq27.3-Xq28 and a ～3.1 Mb duplication of the X q28 region in Patient 2 and a ～41.8 Kb deletion in Patient 3. SNP-array was shown to be important to map for deletion breakpoints. A comprehensive molecular analysis in patients with Hunter syndrome, especially in the ones presenting the severe form, is important to the understanding of the genetic determinants of the phenotype and for the genetic counseling to be provided to the families.     

Prevalence of diabetes and intermediate hyperglycemia among adults from the first multinational study of noncommunicable diseases in six Central American countries: the Central America Diabetes Initiative (CAMDI)

OBJECTIVE

The increasing burdens of obesity and diabetes are two of the most prominent threats to the health of populations of developed and developing countries alike. The Central America Diabetes Initiative (CAMDI) is the first study to examine the prevalence of diabetes in Central America.

RESEARCH DESIGN AND METHODS

The CAMDI survey was a cross-sectional survey based on a probabilistic sample of the noninstitutionalized population of five Central American populations conducted between 2003 and 2006. The total sample population was 10,822, of whom 7,234 (67%) underwent anthropometry measurement and a fasting blood glucose or 2-h oral glucose tolerance test.

RESULTS

The total prevalence of diabetes was 8.5%, but was higher in Belize (12.9%) and lower in Honduras (5.4%). Of the screened population, 18.6% had impaired glucose tolerance/impaired fasting glucose.

CONCLUSIONS

As this population ages, the prevalence of diabetes is likely to continue to rise in a dramatic and devastating manner. Preventive strategies must be quickly introduced.Apparent changes in access to cheap, energy-dense food, urbanization, and adoption of sedentary lifestyles in the countries of Central America have raised concerns about the rapid emergence of obesity and diabetes in the region. Diabetes and related chronic conditions in Central America have been largely neglected by epidemiologic and surveillance programs in recent decades, however, because other issues, such as under-nutrition, infectious diseases, and armed conflict, were regarded as much more pressing health threats.The Central America Diabetes Initiative (CAMDI) is the first population-based multinational study to examine the prevalence of diabetes and risk factors in Central America. We report here the main findings from the multinational analyses of this survey.     

Characterisation of the anti-inflammatory and antinociceptive activities and the mechanism of the action of Lippia gracilis essential oil

Aim of the study

Lubricating gut pill (LGP), a traditional Chinese formula, had been conformed to improve the loperamide-induced rat constipation by stimulation of Cl⁻ secretion, but its mechanism has not been fully explored. Thus, the purpose of this study was to identify the action sites of LGP-stimulated Cl⁻ secretion across rat distal colonic mucosa.

Materials and methods

Rat distal colonic mucosa was mounted in Ussing chambers and short circuit current (I_SC), apical Cl⁻ current and basolateral K⁺ current were recorded. Intracellular cyclic adenosine monophosphate (cAMP) content and protein kinase A (PKA) activity were determined with ELISA kit and the non-radioactive PepTag test, respectively.

Results

LGP at 800 μg/ml elicited a sustained increase in Cl⁻ secretory response, which was inhibited by CFTR_inh172, a cystic fibrosis transmembrane conductance regulator (CFTR) inhibitor. Permeabilizing apical membrane with nystatin revealed that LGP-stimulated basolateral K⁺ current was significantly inhibited by KCNQ1 K⁺ channel inhibitor chromanol 293B. LGP-stimulated I_SC was markedly reduced by pretreatment with cis-N-[2-phenylcyclopentyl]-azacyclotridec-1-en-2amine (MDL-12,330A) and N-[2-(p-bromocinnamylamino)ethyl]-5-isoquinolinesulfonamide (H-89), but not with inhibitors of Ca²⁺-dependent signaling pathway. Treatment of tissue with LGP resulted in an increase in intracellular cAMP level and the activation in protein kinase A. The E-prostanoid₄ (EP)₄ receptor antagonist L-161,982 completely eliminated LGP-induced response.

Conclusions

The results showed that LGP enhances Cl⁻ and fluid secretion via prostanoid receptor signaling and also cAMP and protein kinase A pathway, subsequently triggering the activation of apical Cl⁻ channels mostly CFTR and basolateral cAMP-dependent K⁺ channel.