Attenuated portal hypertension in germ-free mice: Function of bacterial flora on the development of mesenteric lymphatic and blood vessels

Intestinal bacterial flora may induce splanchnic hemodynamic and histological alterations that are associated with portal hypertension (PH). We hypothesized that experimental PH would be attenuated in the complete absence of intestinal bacteria. We induced prehepatic PH by partial portal vein ligation (PPVL) in germ-free (GF) or mice colonized with altered Schaedler's flora (ASF). After 2 or 7 days, we performed hemodynamic measurements, including portal pressure (PP) and portosystemic shunts (PSS), and collected tissues for histomorphology, microbiology, and gene expression studies. Mice colonized with intestinal microbiota presented significantly higher PP levels after PPVL, compared to GF, mice. Presence of bacterial flora was also associated with significantly increased PSS and spleen weight. However, there were no hemodynamic differences between sham-operated mice in the presence or absence of intestinal flora. Bacterial translocation to the spleen was demonstrated 2 days, but not 7 days, after PPVL. Intestinal lymphatic and blood vessels were more abundant in colonized and in portal hypertensive mice, as compared to GF and sham-operated mice. Expression of the intestinal antimicrobial peptide, angiogenin-4, was suppressed in GF mice, but increased significantly after PPVL, whereas other angiogenic factors remained unchanged. Moreover, colonization of GF mice with ASF 2 days after PPVL led to a significant increase in intestinal blood vessels, compared to controls. The relative increase in PP after PPVL in ASF and specific pathogen-free mice was not significantly different. CONCLUSION In the complete absence of gut microbial flora PP is normal, but experimental PH is significantly attenuated. Intestinal mucosal lymphatic and blood vessels induced by bacterial colonization may contribute to development of PH.

Estimation of micro-flora associated with different stages of Macrobrachium rosenbergii (de Man)

The bacterial flora occurring in muscle, haemolymph, hepatopancreas and gill of brood, juveniles, water, eggs, larvae and rearing water were estimated by selective plate count technique for Entrobacteriaceae, Streptococaceae and Vibrionaceae members. The total viable bacterial count was estimated by total plate count technique on nutrient agar. The total viable counts of bacteria were lowest in water from 6.10x10² CFU/mL) and highest in egg (6.06x10super(8) CFU/g). In brood the total counts were varying from 1.62x10² CFU/g in muscle to 2.20x10super(5) CFU/g in gills. In juveniles, the total plate counts were varying from 2.8x10super(4) CFU/g in muscles to 3.67x10 super(8) CFU/g in hepatopancreas. Selective plate counts show that Enterobacteriaceae members dominate in egg and gills of brood and hepatopancreas of juveniles. Vibrios were found to be dominant in water and larvae of rearing tank. Haemolymph of brood was sterile and did not contain any bacteria while muscle of juvenile was having very low count of total viable bacteria.

Succession of bacterial genera during iced storage of three species of tropical prawns, Penaeus indicus, Matapenaeus dobsoni and M. affinis

The native bacterial flora of ocean fresh tropical prawns, Penaeus indicus, Metapenaeus dobsoni and M. affinis was more or less similar, mainly consisting of Pseudomonas, Acinetobacter, Moraxella and Arthrobacter. A definite succession of bacterial genera during iced storage was observed in these prawns. As the day of ice storage increased, the proportion of Acinetobacter and Moraxella also increased considerably and constituted 70-78% of the flora at the time of spoilage. Spoilage by Pseudomonas was very not significant in prawns under iced storage.

Microbial flora of selected species o crustaceans

The thesis deals with the bacterial flora of the Cochin backwaters. Sediment and the prawns caught from these backwaters in quantitative and qualitative terms, their growth in relation to temperature, their susceptibility to various antibiotics, their role in terms of food for juvenile prawns and the presence of bacteria of public health significance. According to the researcher such a comprehensive study would be of some relevance to shell-fish processing industries apart from its academic value. The effect of antibiotics on the bacteria and the utility of bacteria as food for the juvenile prawns are studied and presented in different chapters.

Patogénese de infecções causadas por bactérias da flora endógena

A flora microbiana humana cujos elementos major são bactérias, tem sido caracterizada como uma componente essencial do corpo humano. A sua importância baseia-se no seu envolvimento benéfico numa variedade de funções metabólicas, imunitárias e antimicrobianas. Os resultados destas funções incluem a homeostasia do organismo humano. Contudo, a flora microbiana humana tem sido associada com o desenvolvimento de numerosas infecções denominadas por infecções endógenas tais como as infecções orais. Estas infecções são comuns nos hospedeiros comprometidos, o que contribui para o aumento do seu significado clínico. Nesta dissertação foi feita uma abordagem à patogénese bacteriana assim como aos passos do processos infecciosos e aos factores de virulência. Foi também feita a associação destes à susceptibilidade do hospedeiro com o propósito de compreender os seus contributos para o desenvolvimento das infecções endógenas. Por outro lado, foram exploradas algumas consequências sistémicas infecciosas (endocardite infecciosa) e não infecciosas (aterosclerose) de infecções orais causadas pela flora bacteriana oral.

Conjunctival flora, Schirmer's tear test, intraocular pressure, and conjunctival cytology in neotropical primates from Salvador, Brazil

Background: This study aimed to establish reference values for selected ophthalmic diagnostic tests in healthy neotropical primates from Salvador, Brazil. Methods: A total of 73 intact adults, including Callithrix jacchus (n = 31), Callithrix penicillata (n = 8), Cebus sp. (n = 22), and Cebus xanthosternos (n = 9) were used to evaluate the normal conjunctival bacterial flora. Cebus xanthosternos (n = 12) were used to evaluate tear production with Schirmer's tear test (STT), intraocular pressure (IOP), and conjunctival cytology. Results: For all animals evaluated, Gram-positive bacteria were predominant. Results of the diagnostic tests in Cebus xanthosternos were as follows: STT: 14.92 ± 5.46 mm/minutes, IOP: 19.62 ± 4.57 mmHg, and conjunctival cytology revealed intermediate squamous epithelial cells in great quantities. Conclusions: These ophthalmic reference values will be particularly useful to diagnose discrete or unusual pathological changes in the neotropical primates eye. © 2013 John Wiley & Sons A/S.

Bacterial diversity within the human subgingival crevice

Molecular, sequence-based environmental surveys of microorganisms have revealed a large degree of previously uncharacterized diversity. However, nearly all studies of the human endogenous bacterial flora have relied on cultivation and biochemical characterization of the resident organisms. We used molecular methods to characterize the breadth of bacterial diversity within the human subgingival crevice by comparing 264 small subunit rDNA sequences from 21 clone libraries created with products amplified directly from subgingival plaque, with sequences obtained from bacteria that were cultivated from the same specimen, as well as with sequences available in public databases. The majority (52.5%) of the directly amplified 16S rRNA sequences were <99% identical to sequences within public databases. In contrast, only 21.4% of the sequences recovered from cultivated bacteria showed this degree of variability. The 16S rDNA sequences recovered by direct amplification were also more deeply divergent; 13.5% of the amplified sequences were more than 5% nonidentical to any known sequence, a level of dissimilarity that is often found between members of different genera. None of the cultivated sequences exhibited this degree of sequence dissimilarity. Finally, direct amplification of 16S rDNA yielded a more diverse view of the subgingival bacterial flora than did cultivation. Our data suggest that a significant proportion of the resident human bacterial flora remain poorly characterized, even within this well studied and familiar microbial environment.

Identification of interdomain sequences promoting the intronless evolution of a bacterial protein family.

In the evolution of eukaryotic genes, introns are believed to have played a major role in increasing the probability of favorable duplication events, chance recombinations, and exon shuffling resulting in functional hybrid proteins. As a rule, prokaryotic genes lack introns, and the examples of prokaryotic introns described do not seem to have contributed to gene evolution by exon shuffling. Still, certain protein families in modern bacteria evolve rapidly by recombination of genes, duplication of functional domains, and as shown for protein PAB of the anaerobic bacterial species Peptostreptococcus magnus, by the shuffling of an albumin-binding protein module from group C and G streptococci. Characterization of a protein PAB-related gene in a P. magnus strain with less albumin-binding activity revealed that the shuffled module was missing. Based on this fact and observations made when comparing gene sequences of this family of bacterial surface proteins interacting with albumin and/or immunoglobulin, a model is presented that can explain how this rapid intronless evolution takes place. A new kind of genetic element is introduced: the recer sequence promoting interdomain, in frame recombination and acting as a structure-less flexibility-promoting spacer in the corresponding protein. The data presented also suggest that antibiotics could represent the selective pressure behind the shuffling of protein modules in P. magnus, a member of the indigenous bacterial flora.

Spoilage pattern of five species of Australian prawns: Deterioration is influenced by environment of capture and mode of storage

Five species of commercial prawns Penaeus plebejus, P. merguiensis, P. semisulcatus/P. esculentus and M. bennettae, were obtained from South-East and North Queensland, chilled soon after capture and then stored either whole or deheaded on ice and ice slurry, until spoilage. Total bacterial counts, total volatile nitrogen, K-values and total demerit scores were assessed at regular intervals. Their shelf lives ranged from 10-17 days on ice and >20 days on ice slurry. Initial bacterial flora on prawns from shallower waters (4-15m) were dominated by Gram-positives and had lag periods around 7 days, whereas prawns from deeper waters (100m) were dominant in Pseudomonas spp. with no lag periods in bacterial growth. The dominant spoiler in ice was mainly Pseudomonas fragi whereas the main spoiler in ice slurry was Shewanella putrefaciens. Bacterial interactions seem to play a major role in the patterns of spoilage in relation to capture environment and pattern of storage

Mediastinitis after cardiac surgery

Mediastinitis as a complication after cardiac surgery is rare but disastrous increasing the hospital stay, hospital costs, morbidity and mortality. It occurs in 1-3 % of patients after median sternotomy. The purpose of this study was to find out the risk factors and also to investigate new ways to prevent mediastinitis. First, we assessed operating room air contamination monitoring by comparing the bacteriological technique with continuous particle counting in low level contamination achieved by ultra clean garment options in 66 coronary artery bypass grafting operations. Second, we examined surgical glove perforations and the changes in bacterial flora of surgeons' fingertips in 116 open-heart operations. Third, the effect of gentamicin-collagen sponge on preventing surgical site infections (SSI) was studied in randomized controlled study with 557 participants. Finally, incidence, outcome, and risk factors of mediastinitis were studied in over 10,000 patients. With the alternative garment and textile system (cotton group and clean air suit group), the air counts fell from 25 to 7 colony-forming units/m3 (P<0.01). The contamination of the sternal wound was reduced by 46% and that of the leg wound by >90%. In only 17% operations both gloves were found unpunctured. Frequency of glove perforations and bacteria counts of hands were found to increase with operation time. With local gentamicin prophylaxis slightly less SSIs (4.0 vs. 5.9%) and mediastinitis (1.1 vs. 1.9%) occurred. We identified 120/10713 cases of postoperative mediastinitis (1.1%). During the study period, the patient population grew significantly older, the proportion of women and patients with ASA score >3 increased significantly. In multivariate logistic regression analysis, the only significant predictor for mediastinitis was obesity. Continuous particle monitoring is a good intraoperative method to control the air contamination related to the theatre staff behavior during individual operation. When a glove puncture is detected, both gloves are to be changed. Before donning a new pair of gloves, the renewed disinfection of hands will help to keep their bacterial counts lower even towards the end of long operation. Gentamicin-collagen sponge may have beneficial effects on the prevention of SSI, but further research is needed. Mediastinitis is not diminishing. Larger populations at risk, for example proportions of overweight patients, reinforce the importance of surveillance and pose a challenge in focusing preventive measures.

Bacteriology of chilled water during the preservation of fish

Except for the preliminary studies at Torry Research Station in Scotland, no results have been reported on the succession of the bacterial flora during the storage of fish in chilled water. The present work was undertaken to elucidate the dynamics of bacterial population changes in chilled fresh water under comparable conditions of storage in melting ice (+1° to +3°C.) which has been earlier studied by de Silva in 1960.

Ecology and production in two sandy beaches of Goa. Part (A) Distribution of bacteria in Colva and Siridaon in relation to certain environmental parameters

Qualitative and quantitative studies on the bacterial flora of two beaches viz., Colva and Siridaon at high tide, mid-tide and low tide levels during the pre-monsoon period were made. Estimations of important nutrients, like inorganic phosphates and nitrates and organic carbon have been made and correlation with the bacterial counts is being attempted. Definite correlation between bacterial population and organic carbon is seen however, no correlation is observed between bacterial counts and other physicochemical parameters.

Effects of dietary supplementation of commercial human probiotic and antibiotic on the growth rate and content of intestinal microflora in ornamental fishes

The effects of dietary supplementation of commercial human probiotic, Lactobacil and antibiotic, oxytetracycline on the growth, survival, disease resistance and content of intestinal microflora in two ornamental fishes, viz., goldfish, Carassius auratus and swordtail, Xiphophorus helleri were studied. The total wet weight gain, food conversion ratio and specific growth rate of C. auratus did not vary significantly (p>0.05) among treatments. While in X. helleri, significant differences existed in the total wet weight gain, survival, food conversion ratio and specific growth rate among treatment groups (p<0.05). The counts of antibiotic resistant bacteria in fish gut increased with days of culture in all the treatments and the increase was more in antibiotic fed fishes. A reduction in the development of antibiotic resistance among the bacterial flora of fish gut was noticed in probiotic fed groups of C auratus and X. helleri. The results of the present study revealed that the effects of human probiotic on the growth, survival and disease resistance of ornamental fishes are variable and difficult to reproduce the similar effect on different species.

Relação entre a Infeção por Escherichia coli Aderente-Invasina e a Doença de Crohn

Projeto de Pós-Graduação/Dissertação apresentado à Universidade Fernando Pessoa como parte dos requisitos para obtenção do grau de Mestre em Ciências Farmacêuticas