Bacterial Colonization Patterns Research Articles

Increased Age, but Not Parity Predisposes to Higher Bacteriuria Burdens Due to Streptococcus Urinary Tract Infection and Influences Bladder Cytokine Responses, Which Develop Independent of Tissue Bacterial Loads.

Streptococcus agalactiae causes urinary tract infection (UTI) in pregnant adults, non-pregnant adults, immune-compromised individuals and the elderly. The pathogenesis of S. agalactiae UTI in distinct patient populations is poorly understood. In this study, we used murine models of UTI incorporating young mice, aged and dam mice to show that uropathogenic S. agalactiae causes bacteriuria at significantly higher levels in aged mice compared to young mice and this occurs coincident with equivalent levels of bladder tissue colonisation at 24 h post-infection (p.i.). In addition, aged mice exhibited significantly higher bacteriuria burdens at 48 h compared to young mice, confirming a divergent pattern of bacterial colonization in the urinary tract of aged and young mice. Multiparous mice, in contrast, exhibited significantly lower urinary titres of S. agalactiae compared to age-matched nulliparous mice suggesting that parity enhances the ability of the host to control S. agalactiae bacteriuria. Additionally, we show that both age and parity alter the expression levels of several key regulatory and pro-inflammatory cytokines, which are known to be important the immune response to UTI, including Interleukin (IL)-1β, IL-12(p40), and Monocyte Chemoattractant Protein-1 (MCP-1). Finally, we demonstrate that other cytokines, including IL-17 are induced significantly in the S. agalactiae-infected bladder regardless of age and parity status. Collectively, these findings show that the host environment plays an important role in influencing the severity of S. agalactiae UTI; infection dynamics, particularly in the context of bacteriuria, depend on age and parity, which also affect the nature of innate immune responses to infection.

Bacterial microbiota associated with flower pollen is influenced by pollination type, and shows a high degree of diversity and species-specificity.

Diverse microorganisms colonise the different plant-microhabitats, such as rhizosphere and phyllosphere, and play key roles for the host. However, bacteria associated with pollen are poorly investigated, despite its ecological, commercial and medical relevance. Due to structure and nutritive composition, pollen provides a unique microhabitat. Here the bacterial abundance, community structure, diversity and colonization pattern of birch, rye, rapes and autumn crocus pollens were examined, by using cultivation, high-throughput sequencing and microscopy. Cultivated bacteria belonged to Proteobacteria, Actinobacteria and Firmicutes, with remarkable differences at species level between pollen species. High-throughput sequencing of 16S rRNA gene amplicon libraries showed Proteobacteria as the dominant phylum in all pollen species, followed by Actinobacteria, Acidobacteria and Firmicutes. Both plant species and pollination type significant influenced structure and diversity of the pollen microbiota. The insect-pollinated species possessed a more similar microbiota in comparison to the wind-pollinated ones, suggesting a levelling effect by insect vectors. Scanning electron microscopy as well as fluorescent in situ hybridisation coupled with confocal laser scanning microscopy (FISH-CLSM) indicated the tectum surface as the preferred niche of bacterial colonisation. This work is the most comprehensive study of pollen microbiology, and strongly increases our knowledge on one of the less investigated plant-microhabitats.

Cesarean Delivery and Neonatal Intestinal Colonization

Research Article| October 01 2016 Cesarean Delivery and Neonatal Intestinal Colonization AAP Grand Rounds (2016) 36 (4): 47. https://doi.org/10.1542/gr.36-4-47 Views Icon Views Article contents Figures & tables Video Audio Supplementary Data Peer Review Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Cite Icon Cite Search Site Citation Cesarean Delivery and Neonatal Intestinal Colonization. AAP Grand Rounds October 2016; 36 (4): 47. https://doi.org/10.1542/gr.36-4-47 Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search toolbar search search input Search input auto suggest filter your search All PublicationsAll JournalsAAP Grand RoundsPediatricsHospital PediatricsPediatrics In ReviewNeoReviewsAAP NewsAll AAP Sites Search Advanced Search Topics: cesarean section, intestines, microbial colonization, newborn Source: Stokholm J, Thorsen J, Chawer BL, et al. Cesarean section changes neonatal gut colonization. J Allergy Clin Immunol. 2016; 138(3): 881– 889.e2; doi: https://doi.org/10.1016/j.jaci.2016.01.028Google Scholar Investigators from multiple institutions in Denmark conducted a prospective study to identify the relationship between route of delivery and subsequent bacterial colonization of the gastrointestinal tract and the airway in the first 12 months of life. Study participants included mothers and infants who had been enrolled in the Copenhagen Prospective Studies on Asthma, a cohort study of pregnant Danish women and their offspring. For the study, delivery route was categorized as vaginal, emergency cesarean (failed trial of labor), or elective cesarean (membranes ruptured at delivery). Fecal samples were collected and cultured on study children at 1 week, 1 month, and 1 year of life; hypopharyngeal samples were collected at 1 week, 1 month, and 3 months of life. Demographic information collected included maternal age, household income, maternal asthma, maternal smoking during pregnancy, pregnancy complications, the use of intrapartum antibiotics, older children in the home, and duration of breastfeeding. Rates of positive fecal and airway cultures for individual bacteria were compared among children born vaginally or by cesarean delivery. Of the 700 children in the cohort, 549 (78%) were born vaginally, 85 (12%) by emergency cesarean, and 66 (9%) by elective cesarean. All mothers who had cesarean delivery received intrapartum antibiotics compared to 13% of those who delivered vaginally. Fecal and airway samples were obtained on over 90% of enrolled newborns at most time points. The investigators found that at 1 week of life, intestinal colonization with Citrobacter freundii, Clostridium species, Enterobacter cloacae, Enterococcus faecalis, Klebsiella species, and Staphylococcus aureus were significantly associated with cesarean delivery (for either reason), and colonization with E. coli was significantly associated with vaginal delivery. These associations declined over time and disappeared by 1 year of life. No associations were found between route of delivery and airway colonization. The authors conclude that neonates delivered by cesarean section show a pattern of bacterial colonization in the first week of life that differs from that of babies delivered vaginally. They speculate that these differences may play a role in the development of immunemediated disease, such as asthma and allergy, later in life. Dr. Springer has disclosed no financial relationship relevant to this commentary. This commentary does not contain a discussion of an unapproved/investigative use of a commercial product/device. There can be no doubt that while life-saving for some newborns with intrapartum obstetric complications, cesarean delivery is associated with higher incidence of postnatal complications for both mother1–3 and infant.2–5 In the United States, approximately 32% of all deliveries are via cesarean,2 although less than 15% are medically indicated.5 Recently, efforts have been undertaken to reduce the number of cesarean deliveries that are not medically indicated, both from a professional5 as well as economic perspective.6 The authors of the... You do not currently have access to this content.

Epidemiology and Resistance Patterns of Bacterial and Fungal Colonization of Biliary Plastic Stents: A Prospective Cohort Study.

BackgroundPlastic stents used for the treatment of biliary obstruction will become occluded over time due to microbial colonization and formation of biofilms. Treatment of stent-associated cholangitis is often not effective because of inappropriate use of antimicrobial agents or antimicrobial resistance. We aimed to assess the current bacterial and fungal etiology of stent-associated biofilms, with particular emphasis on antimicrobial resistance.MethodsPatients with biliary strictures requiring endoscopic stent placement were prospectively enrolled. After the retrieval of stents, biofilms were disrupted by sonication, microorganisms were cultured, and isolates were identified by matrix-associated laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry and/or biochemical typing. Finally, minimum inhibitory concentrations (MICs) were determined for various antimicrobial agents. Selected stents were further analyzed by fluorescence in situ hybridization (FISH).ResultsAmong 120 patients (62.5% males, median age 64 years) with biliary strictures (35% malignant, 65% benign), 113 double pigtail polyurethane and 100 straight polyethylene stents were analyzed after a median indwelling time of 63 days (range, 1–1274 days). The stent occlusion rate was 11.5% and 13%, respectively, being associated with a significantly increased risk of cholangitis (38.5% vs. 9.1%, P<0.001). Ninety-five different bacterial and 13 fungal species were detected; polymicrobial colonization predominated (95.8% vs. 4.2%, P<0.001). Enterococci (79.3%), Enterobacteriaceae (73.7%), and Candida spp. (55.9%) were the leading pathogens. Candida species were more frequent in patients previously receiving prolonged antibiotic therapy (63% vs. 46.7%, P = 0.023). Vancomycin-resistant enterococci accounted for 13.7%, extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae with co-resistance to ciprofloxacin accounted for 13.9%, and azole-resistant Candida spp. accounted for 32.9% of the respective isolates.ConclusionsEnterococci and Candida species play an important role in the microbial colonization of biliary stents. Therefore, empirical antimicrobial treatment of stent-associated cholangitis should be guided toward enterococci, Enterobacteriaceae, streptococci, anaerobes, and Candida. To determine causative pathogens, an accurate microbiological analysis of the extracted stent(s) may be helpful.

Cesarean section changes neonatal gut colonization

Delivery by means of cesarean section has been associated with increased risk of childhood immune-mediated diseases, suggesting a role of early bacterial colonization patterns for immune maturation. We sought to describe the influence of delivery method on gut and airway colonization patterns in the first year of life in the Copenhagen Prospective Studies on Asthma in Childhood2010 (COPSAC2010) birth cohort. Seven hundred children from the COPSAC2010 birth cohort participated in this analysis. Fecal samples were collected at age 1week, 1month, and 1year, and hypopharyngeal aspirates were collected at age 1week, 1month, and 3months and cultured for bacteria. Detailed information on delivery method, intrapartum antibiotics, and lifestyle factors was obtained by personal interviews. Seventy-eight percent of the children were born by means of natural delivery, 12% by means of emergency cesarean section, and 9% by means of elective cesarean section. Birth by means of cesarean section was significantly associated with colonization of the intestinal tract by Citrobacter freundii, Clostridium species, Enterobacter cloacae, Enterococcus faecalis, Klebsiella oxytoca, Klebsiella pneumoniae, and Staphylococcus aureus at age 1week, whereas colonization by Escherichia coli was associated with natural birth. At age 1month, these differences were less prominent, and at age 1year, they were not apparent, which was confirmed by means of multivariate data-driven partial least squares analyses. The initial airway microbiota was unaffected by birth method. Delivery by means of cesarean section was associated with early colonization patterns of the neonatal gut but not of the airways. The differences normalized within the first year of life. We speculate that microbial derangements, as indicated in our study, can demonstrate a possible link between delivery by means of cesarean section and immune-mediated disease.

Microbial colonization and lung function in adolescents with cystic fibrosis

With intensified antibiotic therapy and longer survival, patients with cystic fibrosis (CF) are colonized with a more complex pattern of bacteria and fungi. However, the clinical relevance of these emerging pathogens for lung function remains poorly defined. The aim of this study was to assess the association of bacterial and fungal colonization patterns with lung function in adolescent patients with CF. Microbial colonization patterns and lung function parameters were assessed in 770 adolescent European (German/Austrian) CF patients in a retrospective study (median follow-up time: 10years). Colonization with Pseudomonas aeruginosa and MRSA were most strongly associated with loss of lung function, while mainly colonization with Haemophilus influenzae was associated with preserved lung function. Aspergillus fumigatus was the only species that was associated with an increased risk for infection with P. aeruginosa. Microbial interaction analysis revealed three distinct microbial clusters within the longitudinal course of CF lung disease. Collectively, this study identified potentially protective and harmful microbial colonization patterns in adolescent CF patients. Further studies in different patient cohorts are required to evaluate these microbial patterns and to assess their clinical relevance.

Putative invasive pulmonary aspergillosis in critically ill patients with chronic obstructive pulmonary disease: a matched cohort study.

IntroductionPatients with advanced chronic obstructive pulmonary disease (COPD) are at risk for developing invasive pulmonary aspergillosis. A clinical algorithm has been validated to discriminate colonization from putative invasive pulmonary aspergillosis (PIPA) in Aspergillus-positive respiratory tract cultures of critically ill patients. We focused on critically ill patients with COPD who met the criteria for PIPA.MethodsThis matched cohort study included critically ill patients with COPD from two university hospital intensive care units (ICUs). We studied the risk factors for PIPA as well as the impact of PIPA on short- and long-term outcomes. Whether PIPA was associated with a pattern of bacterial colonization and/or infection 6 months before and/or during ICU stay was assessed. In addition, antifungal strategies were reviewed.ResultsFifty cases of PIPA in critically ill patients with COPD in the ICU were matched with one hundred control patients with COPD. The ICU short- and the long-term (at 1 year) mortality were significantly increased in the PIPA group (p < 0.001 for all variables). PIPA was a strong independent risk factor for mortality in the ICU (odds ratio 7.44, 95 % confidence interval 2.93–18.93, p < 0.001) before vasopressor therapy, renal replacement therapy, and duration of mechanical ventilation. Before ICU admission, the use of corticosteroids and antibiotics significantly increased the risk of PIPA (p = 0.004 and p < 0.001, respectively). No significant difference in bacterial etiologic agents responsible for colonization and/or infection was found between the groups. Antifungal treatment was started in 64 % of PIPA cases, with a poor impact on the overall outcome.ConclusionsPIPA was a strong death predictor in critically ill patients with COPD. The use of corticosteroids and antibiotics before ICU admission was a risk factor for PIPA. PIPA was not associated with a specific bacterial pattern of colonization or infection. Prompting antifungal treatment in critically ill patients with COPD who have PIPA may not be the only factor involved in prognosis reversal.

Associations Between Viral and Bacterial Potential Pathogens in the Nasopharynx of Children With and Without Respiratory Symptoms.

Nasopharyngeal (NP) bacterial colonization is necessary for subsequent respiratory and/or invasive infection. Our study aimed at comparing NP bacterial colonization rates between children with and without symptoms of an acute viral respiratory tract infection and examining associations between identified microorganisms. Children 3 months to 6 years of age with and without an acute viral respiratory tract infection were recruited, and a questionnaire was filled. NP samples were examined for Streptococcus pneumoniae (SP), Haemophilus influenzae (HI), Moraxella catarrhalis (MC), Staphylococcus aureus and Streptococcus pyogenes by culture. Viruses were detected with polymerase chain reaction. Median age of the 386 recruited children was 23.4 months, and 127 had no respiratory symptoms. More asymptomatic subjects were found negative for all bacteria tested (P < 0.01). SP (P < 0.01), MC (P = 0.001) and mixed bacterial colonization patterns were more frequent among symptomatic children (P < 0.05). Colonization of symptomatic, virus-positive children with MC was higher than in asymptomatic and/or virus-negative children (P = 0.005). The highest HI and MC colonization rates were recorded in association with influenza virus. A strongly negative association between SP and S. aureus, a higher rate of HI detection among SP colonized children and an increased likelihood of MC detection in the presence of HI were observed. HI colonization was more likely in the presence of respiratory syncytial virus and MC colonization was associated with rhinovirus detection. Viruses are associated with different NP bacterial colonization patterns. Observed pathogens' associations may play a role in disease, and continuous surveillance is required to follow possible effects of interventions such as vaccines.

Persistence of nasal colonization with human pathogenic bacteria and associated antimicrobial resistance in the German general population.

The nares represent an important bacterial reservoir for endogenous infections. This study aimed to assess the prevalence of nasal colonization by different important pathogens, the associated antimicrobial susceptibility and risk factors. We performed a prospective cohort study among 1878 nonhospitalized volunteers recruited from the general population in Germany. Participants provided nasal swabs at three time points (each separated by 4–6 months). Staphylococcus aureus, Enterobacteriaceae and important nonfermenters were cultured and subjected to susceptibility testing. Factors potentially influencing bacterial colonization patterns were assessed. The overall prevalence of S. aureus, Enterobacteriaceae and nonfermenters was 41.0, 33.4 and 3.7%, respectively. Thirteen participants (0.7%) were colonized with methicillin-resistant S. aureus. Enterobacteriaceae were mostly (>99%) susceptible against ciprofloxacin and carbapenems (100%). Extended-spectrum β-lactamase–producing isolates were not detected among Klebsiella oxytoca, Klebsiella pneumoniae and Escherichia coli. Several lifestyle- and health-related factors (e.g. household size, travel, livestock density of the residential area or occupational livestock contact, atopic dermatitis, antidepressant or anti-infective drugs) were associated with colonization by different microorganisms. This study unexpectedly demonstrated high nasal colonization rates with Enterobacteriaceae in the German general population, but rates of antibiotic resistance were low. Methicillin-resistant S. aureus carriage was rare but highly associated with occupational livestock contact.

Emerging spatial patterns in Antarctic prokaryotes.

Recent advances in knowledge of patterns of biogeography in terrestrial eukaryotic organisms have led to a fundamental paradigm shift in understanding of the controls and history of life on land in Antarctica, and its interactions over the long term with the glaciological and geological processes that have shaped the continent. However, while it has long been recognized that the terrestrial ecosystems of Antarctica are dominated by microbes and their processes, knowledge of microbial diversity and distributions has lagged far behind that of the macroscopic eukaryote organisms. Increasing human contact with and activity in the continent is leading to risks of biological contamination and change in a region whose isolation has protected it for millions of years at least; these risks may be particularly acute for microbial communities which have, as yet, received scant recognition and attention. Even a matter apparently as straightforward as Protected Area designation in Antarctica requires robust biodiversity data which, in most parts of the continent, remain almost completely unavailable. A range of important contributing factors mean that it is now timely to reconsider the state of knowledge of Antarctic terrestrial prokaryotes. Rapid advances in molecular biological approaches are increasingly demonstrating that bacterial diversity in Antarctica may be far greater than previously thought, and that there is overlap in the environmental controls affecting both Antarctic prokaryotic and eukaryotic communities. Bacterial dispersal mechanisms and colonization patterns remain largely unaddressed, although evidence for regional evolutionary differentiation is rapidly accruing and, with this, there is increasing appreciation of patterns in regional bacterial biogeography in this large part of the globe. In this review, we set out to describe the state of knowledge of Antarctic prokaryote diversity patterns, drawing analogy with those of eukaryote groups where appropriate. Based on our synthesis, it is clear that spatial patterns of Antarctic prokaryotes can be unique at local scales, while the limited evidence available to date supports the group exhibiting overall regional biogeographical patterns similar to the eukaryotes. We further consider the applicability of the concept of “functional redundancy” for the Antarctic microbial community and highlight the requirements for proper consideration of their important and distinctive roles in Antarctic terrestrial ecosystems.

Patterns of gut bacterial colonization in three primate species.

Host fitness is impacted by trillions of bacteria in the gastrointestinal tract that facilitate development and are inextricably tied to life history. During development, microbial colonization primes the gut metabolism and physiology, thereby setting the stage for adult nutrition and health. However, the ecological rules governing microbial succession are poorly understood. In this study, we examined the relationship between host lineage, captive diet, and life stage and gut microbiota characteristics in three primate species (infraorder, Lemuriformes). Fecal samples were collected from captive lemur mothers and their infants, from birth to weaning. Microbial DNA was extracted and the v4 region of 16S rDNA was sequenced on the Illumina platform using protocols from the Earth Microbiome Project. Here, we show that colonization proceeds along different successional trajectories in developing infants from species with differing dietary regimes and ecological profiles: frugivorous (fruit-eating) Varecia variegata, generalist Lemur catta, and folivorous (leaf-eating) Propithecus coquereli. Our analyses reveal community membership and succession patterns consistent with previous studies of human infants, suggesting that lemurs may serve as a useful model of microbial ecology in the primate gut. Each lemur species exhibits distinct species-specific bacterial diversity signatures correlating to life stages and life history traits, implying that gut microbial community assembly primes developing infants at species-specific rates for their respective adult feeding strategies.

Prevalence of fecal carriage of extended-spectrum- and metallo-β-lactamase-producing gram-negative bacteria among neonates born in a hospital setting in central Saudi Arabia.

BACKGROUND AND OBJECTIVECommensal neonatal fecal flora constitute a reservoir of antibiotic resistance. The aim of this study was to characterize the prevalence of fecal carriage of extended spectrum beta-lactamases (ESBLs) and carbapenemase producing gram-negative bacteria among 150 neonates who were born in two hospitals in central Saudi Arabia.PATIENTS AND METHODSFrom June 2012 to Janauary 2013, 150 healthy neonates ≤7 days of age were screened for intestinal enteric bacteria colonization and the influence of age, mode of delivery, body weight and breast feeding of neonates on colonzation rates. The isolates were identified manually and by VITEK 2 and antibiotic susceptibility was tested. Phenotypic tests were performed to seek ESBL and metallo-β-lactamase (MBL) producers in recovered isolates.RESULTSAmong 150 fecal specimens, 188 gram-negative rods were recovered. E coli (n=130; 69.1%) was the commonest organism followed by Klebsiella pneumoniae (n=23; 12.2%), Pseudomonas aeuroginosa (n=14; 7.5%), Acinetobacter baumannii (n=9; 4.8%), Enterobacter spp. (n=9; 4.8%) and Morganella morganii (n=3; 1.6%). E coli colonization during the first day of life was 95.5% (n=43/45), which was relatively higher than in subsequent days. The colonization rate of E coli among low weight babies (≤3 kg) was significantly higher than fully grown neonates (≥4 kg)(P=.03). The prevalence of ESBL and MBL was 15.0% (n=28/188) and 1.6% (n=3/188). The prevalence rates of ESBL in E coli, K pneumoniae, E cloacae, M morganii and E aerogenes were 16.9% (n=22/130), 4.3 % (n=1/23), 60% (n=3/5), 33.3% (n=1/3), and 25% (n=1/4), respectively. All E cloacae with ESBLs and MBLs were resistant to all tested antibiotics including carbapenems.CONCLUSIONWithin the first week of life, the most important determinants of gut enteric bacteria composition in neonates were age in days, body weight, mode of delivery, and type of neonatal feeding. The findings of ESBLs- and MBLs-producing enteric bacteria as neonate-gut colonizers may have wider implication or linkage to prevention of nosocomial and community-acquired infections by these strains.

Early respiratory microbiota composition determines bacterial succession patterns and respiratory health in children.

Many bacterial pathogens causing respiratory infections in children are common residents of the respiratory tract. Insight into bacterial colonization patterns and microbiota stability at a young age might elucidate healthy or susceptible conditions for development of respiratory disease. To study bacterial succession of the respiratory microbiota in the first 2 years of life and its relation to respiratory health characteristics. Upper respiratory microbiota profiles of 60 healthy children at the ages of 1.5, 6, 12, and 24 months were characterized by 16S-based pyrosequencing. We determined consecutive microbiota profiles by machine-learning algorithms and validated the findings cross-sectionally in an additional cohort of 140 children per age group. Overall, we identified eight distinct microbiota profiles in the upper respiratory tract of healthy infants. Profiles could already be identified at 1.5 months of age and were associated with microbiota stability and change over the first 2 years of life. More stable patterns were marked by early presence and high abundance of Moraxella and Corynebacterium/Dolosigranulum and were positively associated with breastfeeding in the first period of life and with lower rates of parental-reported respiratory infections in the consecutive periods. Less stable profiles were marked by high abundance of Haemophilus or Streptococcus. These findings provide novel insights into microbial succession in the respiratory tract in infancy and link early-life profiles to microbiota stability and respiratory health characteristics. New prospective studies should elucidate potential implications of our findings for early diagnosis and prevention of respiratory infections. Clinical trial registered with www.clinicaltrials.gov (NCT00189020).

FRI0526 The Infantile Gut Bacterial Colonization Pattern is Associated with Higher Cytokine Responses but not to the Proportions of Putative Regulatory T Cells in Childhood

BackgroundEstablishment of the gut microbiota commences directly after birth when the neonate is exposed to microbes. The gut microbiota is a major stimulus for the immune system and late acquisition...

Copy number variation of the beta defensin gene cluster on chromosome 8p influences the bacterial microbiota within the nasopharynx of otitis-prone children.

As there is increasing evidence that aberrant defensin expression is related to susceptibility for infectious disease and inflammatory disorders, we sought to determine if copy number of the beta-defensin gene cluster located on chromosome 8p23.1 (DEFB107, 106, 105, 104, 103, DEFB4 and SPAG11), that shows copy number variation as a block, was associated with susceptibility to otitis media (OM). The gene DEFB103 within this complex encodes human beta defensin-3 (hBD-3), an antimicrobial peptide (AP) expressed by epithelial cells that line the mammalian airway, important for defense of mucosal surfaces and previously shown to have bactericidal activity in vitro against multiple human pathogens, including the three that predominate in OM. To this end, we conducted a retrospective case-control study of 113 OM prone children and 267 controls aged five to sixty months. We identified the copy number of the above defined beta-defensin gene cluster (DEFB-CN) in each study subject by paralogue ratio assays. The mean DEFB-CN was indistinguishable between subjects classified as OM prone based on a recent history of multiple episodes of OM and control subjects who had no history of OM (4.4±0.96 versus 4.4±1.08, respectively: Odds Ratio [OR]: 1.16 (95% CI: 0.61, 2.20). Despite a lack of direct association, we observed a statistically significant correlation between DEFB-CN and nasopharyngeal bacterial colonization patterns. Collectively, our findings suggested that susceptibility to OM might be mediated by genetic variation among individuals, wherein a DEFB-CN less than 4 exerts a marked influence on the microbiota of the nasopharynx, specifically with regard to colonization by the three predominant bacterial pathogens of OM.

Enterococcus faecalis from healthy infants modulates inflammation through MAPK signaling pathways.

Colonizing commensal bacteria after birth are required for the proper development of the gastrointestinal tract. It is believed that bacterial colonization pattern in neonatal gut affects gut barrier function and immune system maturation. Studies on the development of faecal microbiota in infants showed that the neonatal gut was first colonized with enterococci followed by other microbiota such as Bifidobacterium. Other studies showed that babies who developed allergy were less often colonized with Enterococcus during the first month of life as compared to healthy infants. Many studies have been conducted to elucidate how bifidobacteria or lactobacilli, some of which are considered probiotic, regulate infant gut immunity. However, fewer studies have been focused on enterococi. In our study, we demonstrate that E. faecalis, isolated from healthy newborns, suppress inflammatory responses activated in vivo and in vitro. We found E. faecalis attenuates proinflammatory cytokine secretions, especially IL-8, through JNK and p38 signaling pathways. This finding shed light on how the first colonizer, E.faecalis, regulates inflammatory responses in the host.

Autogenous Bone Grafts Contamination After Exposure to the Oral Cavity

The purpose of this paper was to analyze specimens of autogenous bone block grafts exposed to the oral cavity after ridge reconstructions. Specimens of chronic suppurative osteomyelitis (CSO) of the jaws were used as comparison for bacterial colonization pattern. For this, 5 specimens of infected autogenous bone grafts were used and 10 specimens of CSO embedded in paraffin were stained with Brown and Brenn technique and analyzed under light microscopy. The results showed a similar colonization pattern in both situations, with the establishment of bacterial biofilm and the predominance of Gram-positive bacteria. The conclusion was that the similarity in bacterial distribution and colonization between autogenous bone grafts and CSO stresses the necessity of more invasive procedures for the treatment of the autogenous bone grafts early exposed to the oral cavity.

Commensal and probiotic bacteria may prevent NEC by maturing intestinal host defenses

Necrotizing enterocolitis (NEC) is a devastating disease of prematurity with significant morbidity and mortality. Immaturity of intestinal host defenses predisposes the premature infant gut to injury. An abnormal bacterial colonization pattern with a deficiency of commensal bacteria may lead to a further breakdown of these host defense mechanisms, predisposing the infant to NEC. The presence of probiotic and commensal bacteria within the gut has been shown to mature the intestinal defense system through a variety of mechanisms. We have shown that commensal and probiotic bacteria can promote intestinal host defenses by reducing apoptotic signaling, blocking inflammatory signaling, and maturing barrier function in immature intestinal epithelia. Future studies aimed at elucidating the mechanisms by which probiotic and commensal bacteria exert their effects will be critical to developing effective preventive therapies for NEC.

Necrotizing Enterocolitis: Insights into the Pathogenesis of this Challenging Disease

Abstract Download Free Sample Necrotizing enterocolitis is an acute inflammatory necrosis of bowel that primarily afflicts premature infants in the neonatal intensive care unit setting. Although patients who develop this disease have high morbidity and mortality rates, the pathogenesis is poorly understood, and therefore there are no specific preventive or treatment strategies that have been clearly effective. Recent studies have suggested that the pathophysiology of necrotizing enterocolitis includes alterations in the inflammatory response leading to dysregulated pro-inflammatory signaling in premature infants, as well as abnormal intestinal bacterial colonization patterns that can activate these inflammatory pathways, and these factors are discussed in depth in the following chapters. While human milk feedings are currently the standard of care for the prevention of this challenging condition, new approaches will be described based on sound evidence that might have a significant impact for premature in...

English

The formation mechanism of the growth of bacterial colony is studied by comparing the formation of the bacteria with the patterns obtained by Monte Carlo simulations using the diffusion limited aggregation algorithm. For this purpose, the morphological changes of the growing patterns are controlled by a sticking probability parameter, &alpha;, which represents the trajectories of the particles joining to the growing colonies, the complex reactions, and biological dynamics such as concentration of nutrient, temperature, and humidity in the growing environment. Specially, the sticking probability parameter is related to the biological activation and irreversible growth of the bacteria via growth energy for the mobility in the environment and perimeters of the colonies. Morphologies of the aggregation of the bacterial colonies have irregular, fractal, and compact structures. In this study, first, fractal dimensions are assessed for simulations and the real systems. The density of bacteria as &rho;&nbsp;in region defined by circle of radius r centered at initial dropping seed from center through the perimeter is computed by using scaling method.&nbsp; Second, critical exponents of patterns are calculated.&nbsp; As a function of r, &rho; reaches the asymptotic &rho;0&nbsp;(&alpha;) following power-law&nbsp;`r&nbsp;=&nbsp;r0&nbsp;+ Ar&shy;&shy;&shy; &ndash;&nbsp;g&nbsp;with universal exponents &gamma; = 0.47 for &alpha; = 1. The value of the main density for the bacterial patterns has &rho;0&nbsp;~ &alpha;&nbsp;&ndash; &beta;, where &beta; = 0.32 according to the scaling theory. Finally, the results obtained are found in good agreement with the experiments and can be useful for the researchers studying about bacterial colonization patterns. &nbsp; Key words:&nbsp;Monte Carlo simulation, diffusion limited aggregation, sticking probability parameter, critical exponent, bacterial colony formation.