Bacterial isolates were made from the intestinal tracts ofcarious species of cockroaches (Periplaneta americana, Periplaneta brunnea, Periplaneta australasiae, Neostylopyga rhombifolia, Nauphoeta cinerea) trapped from kitchens and stores (houses and hospital), Shigello, flexneri, Salmonella typhi, Escherichia coli and Salmonella sp. were some of the bacteria isolated and identified.
Single strains of Lactobacillus acidophilus and Lact. fermentum, isolated from chicken intestine, were used to study in vitro interactions with Salmonella enteritidis, Salm. pullorum or Salm. typhimurium in an ileal epithelial cell (IEC) radioactive assay. Exclusion, competition and displacement phenomena were investigated by respectively incubating (a) lactobacilli and IEC together, prior to addition of salmonellae, (b) lactobacilli, IEC and salmonellae together, and (c) salmonellae and IEC, followed by the lactobacilli. Lactobacilli were selected for study because of their strong ability to adhere to IEC and poor aggregation with salmonellae. The results demonstrated that Lact. acidophilus significantly reduced (P < 0.05) the attachment of Salm. pullorum to IEC in the tests for exclusion and competition, but not in the displacement tests. Lactobacillus fermentum was found to have some ability to reduce the attachment of Salm. typhimurium to IEC under the conditions of exclusion (P < 0.08), competition (P < 0.09), but not displacement. However, both Lact. acidophilus and Lact. fermentum were unable to reduce the adherence of Salm. enteritidis to IEC under any of the conditions.
A study was conducted to determine the effects of adherent Lactobacillus culture on growth performance, intestinal microbial population, and serum cholesterol level of broilers. Four dietary treatments, consisting of the basal diet (control), basal diet + 0.05, 0.10, or 0.15% Lactobacillus culture (LC), were fed to 2,000 Arbor Acres broiler chicks from 1 to 42 d of age (DOA). The chicks were randomly assigned to 40 cages (50 chicks per cage, 10 cages per diet). The experimental period was 42 d. Body weights and feed to gain ratio were measured at 21 and 42 DOA. The intestinal microbial populations and serum cholesterol levels were determined at 10, 20, 30, and 40 DOA. The results showed that body weights and feed to gain ratios were improved significantly (P < 0.05) when compared to control broilers for broilers fed diets containing 0.05 or 0.10% LC, but not 0.15% LC, at 21 and 42 DOA. Coliform counts in the cecum of birds receiving 0.05% LC at 10, 20, and 30 DOA, and 0.10% at 10 and 20 DOA were significantly lower (P < 0.05) than those of the control birds. The total aerobes, total anaerobes, lactobacilli, and streptococci in the small intestines and ceca of the control birds were not significantly different from those of the treated groups. Serum cholesterol levels were significantly lower (P < 0.05) in broilers fed the three diets containing LC at 30 DOA, and in the birds fed 0.05 or 0.10% LC at 20 DOA.
Twelve Lactobacillus strains isolated from chicken intestine were used to investigate acid and bile tolerance in vitro. Ten out of the 12 strains were slightly affected by 0.3% bile salts, showing a delay of growth (d) of 0.6-37.2 min compared with growth in control cultures. Two strains were not affected by the bile salts. Of the 12 strains, seven could be arbitrarily classified as resistant (d < 15 min) and five as tolerant (15 min < d < or = 40 min). Lactobacillus strains from the caecum showed better tolerance to acid than those from the ileum. Generally, the survival of the ileal strains was very low at pH 1.0 and 2.0, and moderate at pH 3.0. In contrast, caecal Lactobacillus strains could survive at pH 1.0 for up to 2 h of incubation; growth was moderate at pH 2.0 and good at pH 3.0 and 4.0.
Vibrio cholerae is a Gram-negative bacterium that causes diarrheal disease. V. cholerae O1 and O139 serogroups are toxigenic and are known to cause epidemic cholera. These serogroups produce cholera toxin and other accessory toxins such as accessory cholera enterotoxin, zonula occludens toxin, and multifunctional, autoprocessing repeat in toxin (MARTX). In the present study, we incorporated mutated rtxA and rtxC genes that encode MARTX toxin into the existing aminolevulinic acid (ALA) auxotrophic vaccine candidate VCUSM2 of V. cholerae O139 serogroup. The rtxC mutant was named VCUSM9 and the rtxC/rtxA mutant was named VCUSM10. VCUSM9 and VCUSM10 were able to colonize intestinal cells well, compared with the parent vaccine strain, and produced no fluid accumulation in a rabbit ileal loop model. Cell rounding and western blotting assays indicated that mutation of the rtxC gene alone (VCUSM9 strain) did not abolish MARTX toxicity. However mutation of both the rtxA and rtxC genes (VCUSM10) completely abolished MARTX toxicity. Thus we have produced a new, less reactogenic, auxotrophic rtxC/rtxA mutated vaccine candidate against O139 V. cholerae.
Evidence shows that honey improves glycemic control in diabetes mellitus. Besides its hypoglycemic effect, studies indicate that honey ameliorates lipid abnormalities in rats and humans with diabetes. The majority of these studies do not examine the mechanisms by which honey ameliorates glycemic and/or lipid derangements. The gut microbiota is now recognized for its ability to increase energy harvest from the diet and alter lipid metabolism of the host. Recently available data implicate a causal role of these gut microbes in the pathophysiology of obesity, insulin resistance, and diabetes mellitus. In this review, we present some of the latest findings linking gut microbiota to pathogenesis of obesity, insulin resistance, and diabetes mellitus. The review also underlines data that demonstrate the beneficial effects of oligosaccharides on various abnormalities commonly associated with these disorders. Based on the similarities of some of these findings with those of honey, together with the evidence that honey contains oligosaccharides, we hypothesize that oligosaccharides present in honey might contribute to the antidiabetic and other health-related beneficial effects of honey. We anticipate that the possibility of oligosaccharides in honey contributing to the antidiabetic and other health-related effects of honey will stimulate a renewed research interest in this field.
This study examined the potential of Pseudomonas aeruginosa abundance in the intestines of fish as an indicator of exposure to benzo[a]pyrene (BaP). P. aeruginosa populations were enumerated in juvenile African catfish (Clarias gariepinus) injected intramuscularly three days previous with 0, 10, 30, 40, 50 or 70mg/kg of BaP. Hepatic EROD and GST activities and biliary fluorescent aromatic compounds (FACs) 1-OH BaP, 3-OH BaP, 7,8-D BaP and BaP were quantified to investigate agreements between the new indicator and established fish biomarkers. The shape of bacterial population (logarithm of colony-forming unit) dose-response curve generally matched those of biliary FACs concentrations. Conversely, the EROD and GST dose-response curves were generally the mirror images of the bacterial population curve. Changes in intestinal P. aeruginosa population appear to be an indirect effect of BaP exposure because exposure to 0-100μg/ml BaP had no effect on P. aeruginosa populations grown on agar plates containing BaP. Using intestinal P. aeruginosa population of fish as a universal indicator of BaP pollution in aquatic environments is discussed.Conversely, the EROD and GST dose-response curves were generally the mirror images of the bacterial population curve.
This study describes the prevalence of Clostridium difficile toxin (CDT) in loose stool samples from inpatients aged more than two years of a tertiary hospital. A total of 175 samples that had been examined were from stool samples that were sent to the Medical Microbiology & Parasitology Laboratory for various clinical indications. The toxin was detected by a commercial immunochromatograhic test, and the patients' demography, clinical features, treatment and outcomes were analyzed from their medical records. Clostridium difficile toxin was positive in 24 (13.7%) of the stool samples. Male and female were 11 (45.8%) and 13 (54.2%) respectively, with the majority of them aged more than 50 years. Most were from medical wards (n = 21, 87.5%), with the rest from surgical wards (n = 2, 8.3%) and intensive care units (n = 1, 3.4%). All the CDT positive patients had history of prior antibiotic usage within 6 weeks before the detection of the toxin. The mean duration of antibiotics usage was 17.75 (+/- 13.75) days, while the mean duration of diarrhea was 5.21((+/- 5.85) days. Eighteen patients had underlying medical illnesses that were diabetes mellitus, chronic renal disease, hypertension, ischaemic heart disease, cerebrovascular disease and malignancy; with seven of them being CDT positive while on chemotherapy. Stool occult blood test was positive in 15 patients whereas presence of pus cells in the CD positive stool samples were detected in 21 patients. The duration of hospitalization among the patients was 27.96 (+/- 23.22) days.
The nematode Caenorhabditis elegans is hypersusceptible to Burkholderia pseudomallei infection. However, the virulence mechanisms underlying rapid lethality of C. elegans upon B. pseudomallei infection remain poorly defined. To probe the host-pathogen interaction, we constructed GFP-tagged B. pseudomallei and followed bacterial accumulation within the C. elegans intestinal lumen. Contrary to slow-killing by most bacterial pathogens, B. pseudomallei caused fairly limited intestinal lumen colonization throughout the period of observation. Using grinder-defective mutant worms that allow the entry of intact bacteria also did not result in full intestinal lumen colonization. In addition, we observed a significant decline in C. elegans defecation and pharyngeal pumping rates upon B. pseudomallei infection. The decline in defecation rates ruled out the contribution of defecation to the limited B. pseudomallei colonization. We also demonstrated that the limited intestinal lumen colonization was not attributed to slowed host feeding as bacterial loads did not change significantly when feeding was stimulated by exogenous serotonin. Both these observations confirm that B. pseudomallei is a poor colonizer of the C. elegans intestine. To explore the possibility of toxin-mediated killing, we examined the transcription of the C. elegans ABC transporter gene, pgp-5, upon B. pseudomallei infection of the ppgp-5::gfp reporter strain. Expression of pgp-5 was highly induced, notably in the pharynx and intestine, compared with Escherichia coli-fed worms, suggesting that the host actively thwarted the pathogenic assaults during infection. Collectively, our findings propose that B. pseudomallei specifically and continuously secretes toxins to overcome C. elegans immune responses.
The aims of this study were to determine the prevalence and antimicrobial resistance of Listeria, Salmonella, and Yersinia spp. isolated from duck and goose intestinal contents. A total of 471 samples, including 291 duck and 180 goose intestinal contents, were purchased from wet markets between November 2008 and July 2010. Listeria, Salmonella, and Yersinia spp. were isolated from 58 (12.3%), 107 (22.7%), and 80 (17%) of the samples, respectively. It was concluded that Listeria ivanovii, Salmonella Thompson, and Yersinia enterocolitica were the predominant serovars among Listeria, Salmonella, and Yersinia spp., respectively. Moreover, resistance to tetracycline was common in Listeria (48.3%) and Salmonella spp. (63.6%), whereas 51.3% of the Yersinia spp. isolates were resistant to cephalothin. Therefore, continued surveillance of the prevalence of the pathogens and also of emerging antibiotic resistance is needed to render possible the recognition of foods that may represent risks and also ensure the effective treatment of listeriosis, salmonellosis, and yersiniosis.
A study was conducted to determine whether supplementing AminoGut (a commercial dietary supplement containing a mixture of l-glutamine and l-glutamic acid) to broiler chickens stocked at 2 different densities affected performance, physiological stress responses, foot pad dermatitis incidence, and intestinal morphology and microflora. A randomized design in a factorial arrangement with 4 diets [basal diet, basal diet + 0.5% AminoGut from d 1 to 21, basal diet + 0.5% AminoGut from d 1 to 42, and basal diet + virginiamycin (0.02%) for d 1 to 42] and 2 stocking densities [0.100 m(2)/bird (23 birds/pen; LD) or 0.067 m(2)/bird (35 birds/pen; HD)]. Results showed that villi length and crypt depth were not changed by different dietary treatments. However, birds in the HD group had smaller villi (P = 0.03) compared with those of the LD group. Regardless of diet, HD consistently increased the serum concentrations of ceruloplasmin, α-1 acid glycoprotein, ovotransferin, and corticosterone (P = 0.0007), and elevated heterophil to lymphocyte ratio (0.0005). Neither AminoGut supplementation nor stocking density affected cecal microflora counts. In conclusion, under the conditions of this study, dietary supplementation of AminoGut, irrespective of stocking density, had no beneficial effect on growth performance, intestinal morphology, and physiological adaptive responses of broiler chickens raised under hot and humid tropical conditions. However, AminoGut supplementation from d 1 to 42 was beneficial in reducing mortality rate. Also, the increased serum concentrations of a wide range of acute phase proteins together with elevated corticosterone and heterophil to lymphocyte ratio suggested that high stocking density induced an acute phase response either indirectly as a result of increased incidence of inflammatory diseases such as foot pad dermatitis or possibly as a direct physiological response to the stress of high stocking density.
The limited antibiotic options for effective control of methicillin-resistant Staphylococcus aureus infections has led to calls for new therapeutic approaches to combat this human pathogen. An alternative approach to control MRSA is through the use of anti-infective agents that selectively disrupt virulence-mediated pathways without affecting microbial cell viability or by modulating the host natural immune defenses to combat the pathogen.
Avian intestinal spirochaetosis causes problems including delayed onset of lay and wet litter in adult chickens, and results from colonization of the caecae/rectum with pathogenic intestinal spirochaetes (genus Brachyspira). Because avian intestinal spirochaetosis has not previously been studied in South East Asia, this investigation was undertaken in Malaysia. Faecal samples were collected from 25 farms and a questionnaire was administered. Brachyspira species were detected by polymerase chain reaction in 198 of 500 (39%) faecal samples from 20 (80%) farms, including 16 (94%) layer and four (50%) breeder farms. Pathogenic Brachyspira pilosicoli was identified in five (29%) layer and two (25%) breeder farms whilst pathogenic Brachyspira intermedia was detected in nine (53%) layer and one (12.5%) of the breeder farms. Twelve (80%) layer farms had egg production problems and 11 (92%) were positive for Brachyspira: three (25%) for B. pilosicoli and six (50%) for B. intermedia. Of three breeder farms with egg production problems, one was colonized with B. pilosicoli. Three of ten layer farms with wet litter were positive for B. pilosicoli and six for B. intermedia. Of four breeder farms with wet litter, one was colonized with B. pilosicoli and one with B. intermedia. No significant associations were found between colonization and reduced egg production or wet litter, perhaps because so many flocks were colonized. A significant association (P = 0.041) occurred between a high prevalence of colonization and faecal staining of eggs. There were significant positive associations between open-sided housing (P = 0.006), and flocks aged >40 weeks (P < 0.001) and colonization by pathogenic species.
The rising incidence of inflammatory bowel disease in Asia supports the importance of environmental risk factors in disease aetiology. This prospective population-based case-control study in Asia-Pacific examined risk factors prior to patients developing IBD.
Increasing incidence of inflammatory bowel diseases, such as Crohn's disease, in developed nations is associated with changes to the microbial environment, such as decreased prevalence of helminth colonization and alterations to the gut microbiota. We find that helminth infection protects mice deficient in the Crohn's disease susceptibility gene Nod2 from intestinal abnormalities by inhibiting colonization by an inflammatory Bacteroides species. Resistance to Bacteroides colonization was dependent on type 2 immunity, which promoted the establishment of a protective microbiota enriched in Clostridiales. Additionally, we show that individuals from helminth-endemic regions harbor a similar protective microbiota and that deworming treatment reduced levels of Clostridiales and increased Bacteroidales. These results support a model of the hygiene hypothesis in which certain individuals are genetically susceptible to the consequences of a changing microbial environment.
The prevalence and antibiotic susceptibility of intestinal carriage of Gram-negative bacteria among preterm infants admitted to the neonatal intensive care unit (NICU) in a tertiary teaching hospital in Malaysia were determined. A total of 34 stool specimens were obtained from preterm infants upon admission and once weekly up to two weeks during hospitalization. The presumptive colonies of Escherichia coli and Klebsiella pneumoniae were selected for identification, antibiotic susceptibility testing, and subtyping by using pulsed-field gel electrophoresis (PFGE). Out of 76 Gram-negative isolates, highest resistance was detected for amoxicillin/clavulanate (30.8%, n = 16), ceftriaxone (42.3%, n = 22), ceftazidime (28.8%, n = 15), cefoxitin (28.8%, n = 15), aztreonam (36.5%, n = 19), and polymyxin B (23.1%, n = 12). Three colistin resistant K. pneumoniae have also been detected based on E-test analysis. Thirty-nine isolates of K. pneumoniae and 20 isolates of E. coli were resistant to more than three antimicrobial classes and were categorized as multidrug resistant (MDR). PFGE analysis revealed a higher diversity in pulsotypes for K. pneumoniae (18 pulsotypes) in comparison to E. coli (four pulsotypes). In addition, a total of fifteen pulsotypes was observed from 39 MDR K. pneumoniae. The risk factors for antibiotic resistance were assessed using random forest analysis. Gender was found to be the most important predictor for colistin resistant while length, OFC, and delivery mode were showing greater predictive power in the polymyxin B resistance. This study revealed worrying prevalence rates of intestinal carriage of multidrug-resistant K. pneumoniae and E. coli of hospitalized preterm infants in Malaysia, particularly high resistance to polymyxins.
Cholera, a severe form of gastroenteritis, is one of the most widespread diseases in developing countries. The mechanism of intestinal infection caused by V. cholerae O139 remains unclear. In order to explore some morphological aspects of its infection in the intestine including Peyer's patches, we investigated the V. cholerae O139 infection at intestinal site of the rabbit gut-loop model. The electron microscopic analysis revealed denuded mucosal surface with loss of microvilli and integrity of the surface epithelium. Infection of the intestine with V. cholerae O139 induces destruction of villi, microvilli and lining epithelium with exposure of crypts of Lieberkuhn.