Introduction: Carbapenem-resistant A. baumannii (CRAB) represents a public health threat increasing worldwide. We assess the suitability of a loop-mediated isothermal amplification (LAMP) method for ...on-site screening of CRAB in a hospital facility.
Methodology: A set of six primers were designed for recognizing eight distinct sequences on six targets: blaOXA-23-like, blaOXA-24-like, blaOXA-51-like, blaOXA-58-like, blaIMP, and blaVIM. A LAMP method was developed, optimized and evaluated for the identification of CRAB in thirty-three environmental samples from an outbreak in an Intensive Care Unit (ICU) facility.
Results: The sensitivity of the LAMP assay for the detection of A. baumannii was ten-fold higher than the PCR assay (1.0 ng.µL-1). The LAMP assays showed a higher detection rate for CRAB samples and robust diagnosis performance in comparison to a conventional PCR, with clinical sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of 100% for blaOXA-23-like, blaOXA-51-like and blaVIM.
Conclusions: The developed LAMP assays are powerful tools that can be useful in on-site screening of CRAB causing local outbreaks in clinics and hospitals facilities where costs and equipment restraints are imperative.
Molecular analysis of the 16S rDNA of the intestinal microbiota of whiteleg shrimp
Litopenaeus vannamei
was examined to investigate the effect of a
Bacillus
mix (
Bacillus endophyticus
YC3-b,
...Bacillus endophyticus
C2-2,
Bacillus tequilensis
YC5-2) and the commercial probiotic (Alibio
®
) on intestinal bacterial communities and resistance to
Vibrio
infection. PCR and single strain conformation polymorphism (SSCP) analyses were then performed on DNA extracted directly from guts. Injection of shrimp with
V. parahaemolyticus
at 2.5 × 10
5
CFU g
−1
per shrimp followed 168 h after inoculation with
Bacillus
mix or the Alibio probiotic or the positive control. Diversity analyses showed that the bacterial community resulting from the
Bacillus
mix had the highest diversity and evenness and the bacterial community of the control had the lowest diversity. The bacterial community treated with probiotics mainly consisted of α- and γ-proteobacteria, fusobacteria, sphingobacteria, and flavobacteria, while the control mainly consisted of α-proteobacteria and flavobacteria. Differences were grouped using principal component analyses of PCR-SSCP of the microbiota, according to the time of inoculation. In
Vibrio parahaemolyticus
-infected shrimp, the
Bacillus
mix (~33 %) induced a significant increase in survival compared to Alibio (~21 %) and the control (~9 %). We conclude that administration of the
Bacillus
mix induced modulation of the intestinal microbiota of
L. vannamei
and increased its resistance to
V. parahaemolyticus
.
Synbiotic consumption can modulate immune response. This work involves studying the effect of a synbiotic on lymphoid organs and IgA of broilers infected with
and
. A total of 258 one-day-old male ...broilers (
), line COBBAvian48 (free of growth-promoting antibiotics), were distributed into eight treatment groups. A symbiotic mix comprising
HN001 and
MA18/5 M as probiotics and 4.5% (0.045 g g
) of
fructans as prebiotic
dose (one milliliter) was administered through drinking water the first day of life. Bursa, spleen and thymus were analyzed. Broilers treated with the synbiotic, whether or not infected with pathogens, had bigger bursa follicles than the non-treated (
< 0.05), and the ones from the synbiotic group had more lymphocytes than the control group (
< 0.05). Thymus follicles of the synbiotic group were bigger than the control group (
< 0.05). Lesions associated with
infection were found in the bursa, however, in the broilers treated with the synbiotic, the lesions were less intense and were not present after 32 days of life. The synbiotic mix can stimulate the bursa, increasing the size of their follicles and promoting the ability to resist infections caused by
in broilers.
A total of fourteen roasted coffee samples were collected from different local markets in Nayarit, Mexico. Twenty-two fungi isolates were related to the genera
Aspergillus
(54.54%) and
Penicillium
...(4.5%). The strains R16 (0.33 μg/kg), 6N (1.16 μg/kg) and 11 (0.36 μg/kg) tested positive for OTA (ochratoxin A) production in PDA, the other fungi samples were not toxigenic. According to the sequence analysis of their ITS1-5.8S-ITS2 rDNA region, fungi OTA producers correspond to
A. niger
,
A. versicolor
and
Byssochlamys spectabilis
. These three strains were able to produce OTA when inoculated in roasted coffee in concentrations ranging from 75 to 90 μg/kg, after 21 days. Different production stages of roasted coffee (crop management, postharvest practices and storage) along with environmental conditions do not ensure mycotoxigenic fungi free products. This is the first report of OTA natural occurrence in roasted coffee from Nayarit.
Microorganisms isolated from fish can be used as prophylactic tools for aquaculture in the form of probiotic preparations. The purpose of this study was to evaluate the effects of dietary ...administration of the live yeast
Debaryomyces hansenii CBS 8339 on the gilthead seabream (
Sparus aurata L.) innate immune responses. Seabream were fed control or
D. hansenii-supplemented diets (10
6 colony forming units, CFU g
−1) for 4
weeks. Humoral (seric alternative complement and peroxidase activities), and cellular (peroxidase, phagocytic, respiratory burst and cytotoxic activities) innate immune parameters and antioxidant enzymes (superoxide dismutase (SOD) and catalase (CAT)) were measured from serum, head-kidney leucocytes and liver, respectively, after 2 and 4
weeks of feeding. Expression levels of immune-associated genes,
Hep,
IgM,
TCR-β,
NCCRP-1,
MHC-IIα,
CSF-1R,
C3,
TNF-α and
IL-1β, were also evaluated by real-time PCR in head-kidney, liver and intestine. Humoral immune parameters were not significantly affected by the dietary supplementation of yeast at any time of the experiment. On the other hand,
D. hansenii administration significantly enhanced leucocyte peroxidase and respiratory burst activity at week 4. Phagocytic and cytotoxic activities had significantly increased by week 2 of feeding yeast but unchanged by week 4. A significant increase in liver SOD activity was observed at week 2 of feeding with the supplemented diet; however CAT activity was not affected by the dietary yeast supplement at any time of the experiment. Finally, the yeast supplemented diet down-regulated the expression of most seabream genes, except
C3, in liver and intestine and up-regulated all of them in the head-kidney. These results strongly support the idea that live yeast
Debaryomyces hansenii strain CBS 8339 can stimulate the innate immune parameters in seabream, especially at cellular level.
Hemocytes represent one of the most important defense mechanisms against foreign material in Crustacea and are also involved in a variety of other physiological responses. Fluorescent lectin-binding ...assays and cytochemical reactions were used to identify specificity and distribution of carbohydrate moieties and presence of several hydrolytic enzymes, in hemocytes of whiteleg shrimp Litopenaeus vannamei. Two general classes of circulating hemocytes (granular and agranular) exist in L. vannamei, which express carbohydrates residues for FITC-conjugated lectins WGA, LEA, and PNA; UEA and Con-A were not observed. Enzymatic studies indicated that acid phosphatase, nonspecific esterase, and specific esterases were present; alkaline phosphatase was not observed. The enzymes and carbohydrates are useful tools in hemocyte classification and cellular defense mechanism studies.
The effects of elevated dietary arginine on the hematology and immune function of juvenile channel catfish Ictalurus punctatus were evaluated by means of in vivo and in vitro experiments. Healthy ...juvenile channel catfish (average weight, 34.8 g) were fed casein-gelatin-based diets containing 28% crude protein and supplemented with crystalline L-arginine (ARG) at 0.5, 1, 2, or 4% of diet. An intact-protein diet containing 1.3% arginine also was included to investigate the effects of amino acid form (crystalline-free amino acids versus intact protein). Each purified diet was fed to apparent satiation to triplicate groups of fish for 6 weeks. At the end of the experimental feeding period, the fish were injected intraperitoneally with two doses (3 d apart) of 2 mg lipopolysaccharide/kg body weight. Six days after the initial injection, the fish were anesthetized and tissue samples were obtained to evaluate hematological and humoral and cellular immune parameters, including phagocytic activity of peritoneal macrophages, hemoglobin, hematocrit, mean corpuscular volume (MCV), blood cell counts, plasma protein, and hepatic superoxide dismutase activity. High dietary levels (4% ARG) resulted in significantly higher levels of hemoglobin, hematocrit, and circulating erythrocytes. Dietary ARG did not significantly affect MCV and the number of circulating leukocytes, lymphocytes, eosinophils, and monocytes. In vitro, a moderate level (2 mM) of ARG in the culture media was found to be ideal in significantly enhancing phagocytosis. This study demonstrates that some aspects of the immune system of channel catfish are sensitive to changes in dietary ARG.
Abstract
The resident microbiota of three oyster species (Crassostrea corteziensis, Crassostrea gigas and Crassostrea sikamea) was characterised using a high-throughput sequencing approach ...(pyrosequencing) that was based on the V3–V5 regions of the 16S rRNA gene. We analysed the changes in the bacterial community beginning with the postlarvae produced in a hatchery, which were later planted at two grow-out cultivation sites until they reached the adult stage. DNA samples from the oysters were amplified, and 31 008 sequences belonging to 13 phyla (including Proteobacteria, Bacteroidetes, Actinobacteria and Firmicutes) and 243 genera were generated. Considering all life stages, Proteobacteria was the most abundant phylum, but it showed variations at the genus level between the postlarvae and the adult oysters. Bacteroidetes was the second most common phylum, but it was found in higher abundance in the postlarvae than in adults. The relative abundance showed that the microbiota that was associated with the postlarvae and adults differed substantially, and higher diversity and richness were evident in the postlarvae in comparison with adults of the same species. The site of rearing influenced the bacterial community composition of C. corteziensis and C. sikamea adults. The bacterial groups that were found in these oysters were complex and metabolically versatile, making it difficult to understand the host–bacteria symbiotic relationships; therefore, the physiological and ecological significances of the resident microbiota remain uncertain.
Changes in the composition and diversity of the resident microbiota associated with oysters (Crassostrea corteziensis, Crassostrea gigas, Crassostrea sikamea) during commercial production was characterised using pyrosequencing from 16S rRNA gene.
In this study, five microalgal strains were isolated from Bahía de La Paz, Baja California Sur, Mexico and identified as Grammatophora sp., Navícula sp., Rhabdonema sp., Schizochytrium sp., and ...Nitzschia sp., and their evaluation as potential food for Artemia franciscana. The isolated strains were cultured outdoors and harvested after four days. Chaetoceros muelleri was cultured under laboratory conditions and used as control. The protein, lipid, and carbohydrate composition and the fatty acid profiles of the strains were determined by gas chromatography. To assess the effect of microalgal strains on A. franciscana, decapsulated cysts were cultured at outdoor conditions in 15 L containers. The experiment was conducted for twelve days. Samples from the five different feeding treatments were taken at the beginning and end of the experiment to assess number, size, and weight of Artemia larvae. Treatment with Rhabdonema sp. showed larvae with a lower percentage of polyunsaturated fatty acids (PUFAs) while Grammatophora sp. showed those with the greatest PUFA proportion, even more than those fed Chaetoceros muelleri (control). Larvae consuming Schizochytrium sp. had no docosahexanoic (DHA) nor eicosapentaenoic (EPA) fatty acid content. Growth and survival of A. franciscana did not show significant differences among feed treatments, except when it was fed Nitzschia sp., showing lower survival and dry weight. Treatment based on Schizochytrium sp. and Rhabdonema sp. had a greater A. franciscana size but reduced dry weight; additional tests including two or more algal species for every treatment should be carried out to determine the best yield.
PDF
