Heavy Colonization Research Articles

Enterohepatic Helicobacter spp. in colonic biopsies of dogs: molecular, histopathological and immunohistochemical investigations

Enterohepatic Helicobacter spp. have been described colonizing the large intestine and liver of healthy and symptomatic subjects and are thought to have a role in the development of inflammatory bowel disease (IBD). The prevalence of enterohepatic Helicobacter spp. infection in dogs is largely unknown and to our knowledge there are no data about their potential pathogenic role. In light of these considerations, the aims of this study were (i) to assess the prevalence of enterohepatic Helicobacter spp. in colonic biopsies of symptomatic pet dogs and (ii) to evaluate a possible association between Helicobacter spp. colonization status (heavily colonized, poorly colonized and uncolonized biopsies) and histological lesions. Colonic biopsies from 27 pet dogs of different ages were evaluated by family Helicobacteraceae and enterohepatic Helicobacter spp. PCR, histology, and immunohistochemistry for the in situ detection of Helicobacter spp. organisms. 85% and 52% of colonic biopsies were positive by Helicobacteraceae and enterohepatic Helicobacter spp. PCR, respectively. Immunohistochemistry revealed Helicobacter spp. were localized both in the superficial mucus (55%) and within intestinal crypts (33%). Dogs with heavy enterohepatic Helicobacter spp. colonization were significantly younger and had a higher level of mucosal fibrosis/atrophy than dogs with uncolonized or poorly colonized biopsies (p<0.05). These findings contribute to widen current knowledge regarding canine enterohepatic Helicobacter spp., suggesting the infection is rather common in dogs and acquired at an early age. Furthermore, heavy colonization of colonic crypts is associated with chronic inflammatory lesions (fibrosis/atrophy), supporting the role of enterohepatic Helicobacter spp. in the development of canine IBD.

Effcacy of a silver lipidocolloid dressing on heavily colonised wounds: a republished RCT

Nearly all open wounds are contaminated by microorganisms. This generally corresponds to simple bacterial growth, without leading to deleterious effects or compromising the progress of the healing process. In acute wounds, the probability of wound infection increases as the level of contamination does. However, it is more complex for chronic wounds, which are able to contain and tolerate large amounts of bacteria, many times higher than the usual threshold level (>105 bacteria/g of tissue) defining infection in acute wounds,1 without inducing local signs. Nevertheless, many clinical and experimental studies indicate that the probability for chronic wounds to heal properly is limited when the bacterial load exceeds this level of contamination; even when body defences are still able to prevent tissue invasion, bacteria can impair wound healing.

Dental Implant Failure Associated With Bacterial Infection and Long-Term Bisphosphonate Usage

Although the risk of developing osteonecrosis of the jaw for oral implants in patients using oral bisphosphonates (BPs) is low, the devastating complications still require caution. We document a case of severe periimplant infection that developed after the patient had used oral BPs for 3 years. Exposed bone and osteonecrosis persisted for more than 2 months after 1 infected implant was explanted by a dentist unaware that the patient was taking BPs. After oral BPs had been stopped, another involved implant was explanted, sequestra were removed, a primary closure was sutured, and the antibiotic was changed; then the wound was finally under control. The explanted implant with attached bone was processed for undecalcified ground sections, and specimens from the bony lesion were sent to pathology for examination. Osteonecrosis, severe inflammatory osteolysis, and heavy bacterial colonization were found. Patients at risk must be alerted about the potential risks of implant failure and developing BP-related osteonecrosis of the jaw.

The large universal Pantoea plasmid LPP-1 plays a major role in biological and ecological diversification

BackgroundPantoea spp. are frequently isolated from a wide range of ecological niches and have various biological roles, as plant epi- or endophytes, biocontrol agents, plant-growth promoters or as pathogens of both plant and animal hosts. This suggests that members of this genus have undergone extensive genotypic diversification. One means by which this occurs among bacteria is through the acquisition and maintenance of plasmids. Here, we have analyzed and compared the sequences of a large plasmid common to all sequenced Pantoea spp.Results and discussionThe Large PantoeaPlasmids (LPP-1) of twenty strains encompassing seven different Pantoea species, including pathogens and endo-/epiphytes of a wide range of plant hosts as well as insect-associated strains, were compared. The LPP-1 plasmid sequences range in size from ~281 to 794 kb and carry between 238 and 750 protein coding sequences (CDS). A core set of 46 proteins, encompassing 2.2% of the total pan-plasmid (2,095 CDS), conserved among all LPP-1 plasmid sequences, includes those required for thiamine and pigment biosynthesis. Phylogenetic analysis reveals that these plasmids have arisen from an ancestral plasmid, which has undergone extensive diversification. Analysis of the proteins encoded on LPP-1 also showed that these plasmids contribute to a wide range of Pantoea phenotypes, including the transport and catabolism of various substrates, inorganic ion assimilation, resistance to antibiotics and heavy metals, colonization and persistence in the host and environment, pathogenesis and antibiosis.ConclusionsLPP-1 is universal to all Pantoea spp. whose genomes have been sequenced to date and is derived from an ancestral plasmid. LPP-1 encodes a large array of proteins that have played a major role in the adaptation of the different Pantoea spp. to their various ecological niches and their specialization as pathogens, biocontrol agents or benign saprophytes found in many diverse environments.

Oral Microflora: A Comparative Study in HIV and Normal Patients.

The study was designed to compare the oral microbiota in normal and HIV-infected individuals. The study tries to establish a significant shift in oral microflora in HIV-infected patients. Antibiotic sensitivity testing was performed to establish any rise in resistance against the antibiotics. It was a two and half year prospective study conducted in a tertiary care centre. The study group consisted of eighty subjects divided into two groups of control and HIV. The age range for this group was 9-75years. The mean age in this group was 39.7years. The male:female ratio was 2.75:1. Tuberculosis was the most common opportunistic infection in patients with HIV infection. The most common commensal micro organism isolated was the Viridans streptococci in 60% followed by Streptococcus pneumoniae in 23.33%. HIV Group: The most common commensal micro organism isolated was the Viridans streptococci in 42%; this was followed by the Micrococci spp. in 22% cases. S. pneumoniae was isolated in 6% of cases. The colony count for Viridans streptococci showed a heavy growth in 55.56% of cases in controls whereas the same in HIV group was 62.5%. Micrococcus spp. was isolated from 11 subjects in HIV group while it was not isolated from the controls. 50% subjects in the HIV group showed a heavy growth of Klebsiella spp. whereas controls showed only moderate and scanty growth. In patients with CD4+ T cell count less than 50cells/μl we found a heavy colonization of the oral cavity with Micrococcus spp., Acinetobacter and Klebsiella spp. Viridans streptococcus was not isolated in any of the patients with CD4+ T cell count less than 50cells/μl. As CD4+ T cells counts improved to 51-100cells/μl Viridans streptococcus colonies returned and 37.5% patients showed a heavy growth. Micrococcus spp. colonies were isolated till the CD4+ T cells improved up to 300cells/μl. At counts>300cells/μl the oral microbiota became comparable to that of the controls. Many of the opportunistic infections in HIV are caused by commensal bacteria which are otherwise harmless in a normal individual. Our study is unique in that such a study of the oral commensals in HIV patients has never been reported. We found an increased colonization of the oral cavity by Micrococcus spp. which is a normal commensal of the skin.

Antibiotics for ureaplasma in the vagina in pregnancy

Preterm birth is a significant perinatal problem contributing to perinatal morbidity and mortality. Heavy vaginal ureaplasma colonisation is suspected of playing a role in preterm birth and preterm rupture of the membranes. Antibiotics are used to treat infections and have been used to treat pregnant women with preterm prelabour rupture of the membranes, resulting in some short-term improvements. However, the benefit of using antibiotics in early pregnancy to treat heavy vaginal colonisation is unclear. To assess whether antibiotic treatment of pregnant women with heavy vaginal ureaplasma colonisation reduces the incidence of preterm birth and other adverse pregnancy outcomes. We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (31 May 2011). Randomised controlled trials comparing any antibiotic regimen with placebo or no treatment in pregnant women with ureaplasma detected in the vagina. Three review authors independently assessed eligibility and trial quality and extracted data. We included one trial, involving 1071 women. Of these, 644 women between 22 weeks and 32 weeks' gestation were randomly assigned to one of three groups of antibiotic treatment (n = 174 erythromycin estolate, n = 224 erythromycin stearate, and n = 246 clindamycin hydrochloride) or a placebo (n = 427). Preterm birth data was not reported in this trial. Incidence of low birthweight less than 2500 grams was only evaluated for erythromycin (combined, n = 398) compared to placebo (n = 427) and there was no statistically significant difference between the two groups (risk ratio (RR) 0.70, 95% confidence interval (CI) 0.46 to 1.07). There were no statistically significant differences in side effects sufficient to stop treatment between either group (RR 1.25, 95% CI 0.85 to 1.85). There is insufficient evidence to assess whether pregnant women who have vaginal colonisation with ureaplasma should be treated with antibiotics to prevent preterm birth.Preterm birth is a significant perinatal problem. Upper genital tract infections, including ureaplasmas, are suspected of playing a role in preterm birth and preterm rupture of the membranes. Antibiotics are used to treat women with preterm prelabour rupture of the membranes; this may result in prolongation of pregnancy and lowers the risks of maternal and neonatal infection. However, antibiotics may be beneficial earlier in pregnancy to eradicate potentially causative agents.

Genital tract group B streptococcal colonization in pregnant women: a South Indian perspective

During the last few decades, group B Streptococcus (GBS) has emerged as an important pathogen. The major reservoirs for GBS are the vagina and the peri-anal regions/rectum, and the colonization of these regions is a risk factor for subsequent infection in pregnant women and newborns. A prospective study was performed to determine the prevalence of GBS colonization in the vagina and rectum of pregnant women and the antibiotic susceptibility pattern of the isolates. We also aimed to identify risk factors associated with GBS colonization. The vaginal and rectal swabs were inoculated in Todd-Hewitt broth and later subcultured on blood agar for isolation of GBS. A total of 300 pregnant women were enrolled in the study. GBS strains were isolated from seven out of 300 patients, corresponding to a colonization rate of 2.3%. Of the seven patients carrying GBS, isolates were cultured only from vaginal swabs in two cases (28.6%), only from rectal swabs in two cases (28.6%) from both vaginal and rectal swabs in three cases (42.9%). Heavy colonization was present only in 42.9% (3/7) of antenatal women. None of the seven isolates were resistant to penicillin or clindamycin, while one isolate (14.3%) was resistant to erythromycin and five isolates (71.4%) were resistant to tetracycline. Multigravid women and those with previous spontaneous abortion were more frequently colonized by GBS. The GBS colonization rate in our study was low. No resistance to penicillin or clindamycin was seen, while the majority of the isolates were resistant to tetracycline.

Risk factors associated with gut and nasopharyngeal colonization by common Gram-negative species and yeasts in neonatal intensive care units patients

Aim To characterize dynamics of mucosal colonization of neonates by common aerobic Gram negative species and Candida spp. and to identify independent perinatal, neonatal, and environmental factors influencing the colonization process. Study design The nasopharyngeal (n = 1145) and rectal (n = 1242) swabs were collected on admission and thereafter twice a week in neonates with risk factors of early onset sepsis (n = 276) admitted within the first 72 h of life. The association between colonization by different microbes and a total of 22 predefined risk factors was assessed using univariate and multiple logistic regression analyses. Results Throughout the study about half of the patients had rectal (55.8%) or nasopharyngeal colonization (42.8%) with common Gram-negative microorganisms. Colonization dynamics and risk factors were in general similar for a given bacterial species in both mucosal sites; nonfermentative microbes more often found in nasopharyngeal swabs and Enterobacteriaceae in rectal swabs. All organisms except Escherichia coli were influenced by the duration of intensive care unit stay but other risk factors were species specific, perhaps reflecting their mode of acquisition. While colonization by E. coli and Candida albicans was associated with perinatal factors like term birth, vaginal delivery, and breast milk feeding; colonization by Klebsiella pneumoniae, Enteribacter cloacae, Acinetobacter spp. and non-albicans Candida spp. were mostly determined by hospital environment (treatment unit and period, artificial interventions and their duration) and gestation age ≤ 28 weeks. Conclusions The knowledge of risk factor profiles may permit the development of strategies to prevent heavy colonization and subsequent invasive disease in high risk infants.

Arbuscular mycorrhizal development, glomalin‐related soil protein (GRSP) content, and rhizospheric phosphatase activitiy in citrus orchards under different types of soil management

AbstractThe arbuscular mycorrhizal (AM) status with respect to colonization of different AM structures in the citrus roots, spore density and hyphal length density, GRSP content, and phosphatase activity in the citrus rhizosphere were investigated in the orchards at Zigui county of the Three Gorges Region, S China. Four soil managements, no‐tillage and natural grass (NN), no‐tillage and sod culture (NS), half‐tillage and film mulching (HT), and clean‐tillage (CT) were employed in those citrus orchards. Our survey showed heavy AM colonization (36%–89%), indicating a high AM dependency of citrus in our experimental orchards. The colonization of different AM structures, spore density, hyphal length density, GRSP content, and phosphatase activity varied greatly between the no‐tillage and tillage citrus orchards. The highest colonization of different AM structures except the ratio of root length with vesicles (RLV), spore density, hyphal length density, GRSP content, and phosphatase activity was observed in the no‐tillage orchards, and the lowest was found in the tillage orchards. A cluster analysis based on the similarity in AM status, GRSP content, and phosphatase activity showed similarities between the NS citrus orchards and the NN citrus orchards. The data presented here demonstrate that tillage reduced the total AM colonization (RLT), spore density, hyphal length density, GRSP content, and phosphatase activity, while those were recovered in the no‐tillage citrus orchards. So, we propose that no‐tillage and planting grass is an effective way for citrus production and improvement of soil quality in orchards of the study area.

Mycorrhizal and Endophytic Fungal Colonization in Arrhenatherum elatius L. Roots According to the Soil Contamination in Heavy Metals

The aim of this work was to jointly study non-mycorrhizal (dark septate fungi) and mycorrhizal (arbuscular mycorrhizae) colonization along a large range of heavy metal pollution in soil in order to determine the effective contribution of each type of endophytes in relation to heavy metal uptake and tolerance. Hence, eight sites were chosen in the mining area of northern France with respect both to a large range of heavy metal contamination (Cd, Pb, Zn) and monospecific colonization by Arrhenatherum elatius. Root colonization with both arbuscular mycorrhizae (AM) and dark septate fungi (DSF) as well as spore density in rhizospheric soil were estimated in relation to soil characteristics. Mycorrhizal infestation (hyphae, arbuscules and vesicles) was adversely affected by soil pollution almost to exclusion. The intensity of colonization with DSF was very low in presence of AM in non-contaminated soils but higher in polluted soils. The effect of the fungal colonization on the heavy metal tolerance of Arrhenatherum elatius is discussed.

Purified chicken intestinal mucin attenuates Campylobacter jejuni pathogenicity in vitro

Campylobacter jejuni is a major causative agent of diarrhoeal disease worldwide in the human population. In contrast, heavy colonization of poultry typically does not lead to disease and colonized chickens are a major source of Campylobacter infections in humans. Previously, we have shown that chicken (but not human) intestinal mucus inhibits C. jejuni internalization. In this study, we test the hypothesis that chicken mucin, the main component of mucus, is responsible for this inhibition of C. jejuni virulence. Purified chicken intestinal mucin attenuated C. jejuni binding and internalization into HCT-8 cells depending on the site of origin of the mucin (large intestine>small intestine>caecum). C. jejuni invasion of HCT-8 cells was preferentially inhibited compared to bacterial binding to cells. Exposure of the mucin to sodium metaperiodate recovered bacterial invasion levels, suggesting a glycan-mediated effect. However, fucosidase or sialidase pre-treatment of mucin failed to abrogate the inhibition of C. jejuni pathogenicity. In conclusion, differences in the composition of chicken and human intestinal mucin may contribute to the differential outcome of Campylobacter infection of these hosts.

Candida Colonization and Candiduria in Critically Ill Patients in the Intensive Care Unit

Clinical severity of invasive candidiasis in critically ill patients and existing difficulties in timely diagnosis mean that early empirical therapy, based upon a strict clinical and epidemiological judgement, is required in intensive care unit patients. One school of thought is that the clinical severity and epidemiological burden of this disease warrant prophylaxis in all critically ill patients. In reality, however, there are still many open-ended questions with regard to which variables are most apt for selection of patients requiring prophylactic or empirical treatment. As a consequence of a consistently significant correlation between colonization (one or more Candida-positive cultures from non-sterile sites) and subsequent infection, colonization remains the most universally accepted predictive variable with regard to invasive candidiasis. This is particularly true for high density colonization. It has not yet been clarified whether colonization can be used in isolation to identify high-risk patients or if it should be combined with other variables indicating high risk. Additionally, there is still a debate surrounding the question as to whether determination of multisite colonization is required, or whether detecting colonization at one or two specific sites is sufficient for the identification of high-risk patients. From a practical perspective, candiduria (a frequent finding in critically ill patients) appears one of the most promising parameters with regard to single-site assessment, owing to easy sampling procedures. Definitive evidence of a correlation between candiduria and invasive candidiasis is currently still lacking, as the few published studies thus far have yielded conflicting results. It is, however, apparent that candiduria can be reliably considered a surrogate marker of high density of colonization, thereby potentially representing a more practical, less resource-intensive screening marker of heavy colonization and high risk of infection than is currently possible using parameters such as the multiple-site colonization index.

Periodontal disease and macrovascular disease: What is the evidence?

There are several levels of evidence that need to be fulfilled to accept that a putative risk factor is causally associated with a particular disease: These include (i) a biologically plausible scenario by which the exposure contributes to the outcome; (ii) supporting data from epidemiologic studies (cross-sectional, case-control and prospective cohort studies); (iii) evidence from mechanistic, experimental studies; and (iv) ultimately, evidence from intervention studies, ideally randomized controlled trials. Periodontal infections clearly fulfill the biological plausibility requirement. The ulcerated epithelium of the periodontal pocket has a sizeable surface area and is in constant contact with a highly organized biofilm that is inhabited by several bacteria with significant virulence potential. Bacteria have been shown to enter the circulation after even mild manipulation of the periodontal tissues, resulting in repeated transient bacteremias that may facilitate dissemination of oral microbiota at distant sites. Bacterial products and inflammatory mediators that are produced abundantly, locally within the diseased periodontal tissues may also enter the circulation and result in systemic inflammation which may trigger endothelial activation. Molecular mimicry, i.e. the high degree of homology between prokaryotic and mammalian proteins, redirects anti-bacterial antibodies to act also as auto-antibodies, ultimately resulting in activation of, and damage to the vascular endothelium. The possibility of a certain degree of confounding due to common risk factors for atherosclerosis and periodontitis should not, however, be overlooked. Over the past two decades, cross-sectional and prospective cohort studies have demonstrated a significant association between radiographically and clinically assessed periodontitis and coronary heart disease (CHD), broadly defined as myocardial infarction, death due to hospitalization due to CHD, or revascularization procedures. Importantly, these positive associations persist after adjustment for established risk factors for CHD, including age, gender, race, poverty, smoking, diabetes, high blood pressure, body mass index and high serum low density lipoprotein cholesterol. With few exceptions, the above associations have been confirmed in several populations with varying race/ethnicity profiles. Positive associations have also been reported between periodontitis, defined by clinical measures or by seropositivity to important periodontal pathogens, and non-hemorrhagic stroke. Finally, limited recent evidence suggests that periodontitis may be associated with peripheral artery disease after adjustment for concomitant exposures. Epidemiologic evidence also exists on the association between periodontitis and subclinical markers of CVD, including levels of serum C-reactive protein and seropositivity for interleukin 6. Heavy colonization by specific periodontal pathogens was found to be associated with increased intima-media thickness, while DNA from oral bacteria and, in one report, viable invasive periodontal pathogens were recovered from human endarterectomy specimens. Data from intervention studies suggest that treatment of periodontitis may result in lower levels of serum inflammatory mediators such as CRP and IL-6, positive alteration of lipid profiles and improved endothelial function, although the degree of variability is substantial. A randomized clinical trial that employed local antibiotics as adjuncts to mechanical periodontal therapy demonstrated improved endothelial function six months after completion of treatment. Finally, a pilot, multicenter randomized secondary prevention trial of 18-months duration compared periodontal therapy to community dental care, but failed to detect any differences in the incidence of cardiovascular adverse events between the treatment arms. In conclusion, the association between periodontitis and macrovascular disease is biologically plausible; the epidemiologic data and the findings from intervention trials focusing on surrogate markers are supportive; however, the effects of periodontal therapy on clinical macrovascular disease endpoints are largely untested.

Helicobacter pylori infection in patients with chronic urticaria: correlation with pathologic findings in gastric biopsies

Chronic urticaria is a persistent urticaria lasting longer than 6 weeks, affecting 20% of the general population. Various infectious agents have been reported as causes of urticaria, including Helicobacter pylori, which is a common worldwide bacterial infection. Its role in inducing allergic conditions, such as chronic urticaria, has been suggested in some reports and ignored in others. To assess the prevalence of H. pylori infection in patients with chronic urticaria and to explore the possible etiopathogenetic link between them. Thirty-five patients suffering from chronic urticaria and 10 normal control individuals were subjected to upper endoscopic gastric biopsies to assess and semiquantify H. pylori infection and to address other pathologic abnormalities, using routine hematoxylin and eosin staining and Giemsa staining. Forty percent of control subjects and 57% of patients were positive for H. pylori infection, but the difference did not reach statistically significant levels (P = 0.47). The severity of urticarial symptoms was greater in the H. pylori-positive than in the H. pylori-negative group (P = 0.019). Heavy bacterial colonization (P = 0.008) and intense gastric inflammation (P < 0.0001) were associated significantly with severe clinical manifestations. Eighty percent of the H. pylori-positive urticaria group experienced complete remission after receiving eradication therapy for H. pylori. Helicobacter pylori may have a role in the exacerbation of urticarial symptoms, even though it is not involved directly in its etiology, and its eradication may lead to symptom improvement in a considerable number of infected urticaria patients. The severity of symptoms is dependent on the density of bacterial infection and the intensity of inflammatory infiltrate in the gastric biopsy.

Infectious Nosocomial Diarrhea in the Surgical Wards: Role of Parasites and Microbes Imply Stool Analysis

This is the first study to document the etiology of non-outbreak infectious nosocomial diarrhea in surgical wards, in Al-Madinah Al-Munawarh hospitals, Saudi Arabia. Fecal samples were collected from all hospitalized patients in surgical wards having diarrheic stool 72 hours after hospitalization with no co-morbid diarrhea or intestinal disturbances on hospitalization during the period from September, 2007 to March, 2008. They were analyzed by copro-scopical, fecal culture, and copro-ELISA methods. Enteropathogens were revealed in 51.9% of cases; about third of them had combined infections. C.difficile toxin A&B with or without antibiotic use was the leading cause (21.7%), followed by E.coli O157 (17.8%). While parasites were not listed as common causes of infectious nosocomial diarrhea, protozoa were detected in 19.8% of cases; Cryptosporidium parvum (6.6%), B.hominis (6.6%), G.lamblia (3.5%) and E.histolytica (3.1%). Heavy yeast colonization was isolated from 3.5% of cases and Rotavirus coproantigens in 1.2%. Stool specimen analysis 72 h after admission would be of value for parasites and microbes in hospitalized patients. Patients who had prolonged duration of hospitalization, complicated surgical procedures, pre-existing co-morbidity, taking medications especially antibiotics, or at extremes of ages were high risk groups. The numbers of fecal specimens examined, fecal concentration, and fecal ELISA, increase the recovery rate of stool examination. In addition, the morbidity was greater than reported, which implicate the request for stool examination and the role of parasites and microbes as an etiology of nosocomial diarrhea in surgical wards.

Antimicrobial-coated endotracheal tubes: an experimental study

Antibiotic-resistant bacterial biofilm may quickly form on endotracheal tubes (ETTs) and can enter the lungs, potentially causing pneumonia. In an attempt to prevent bacterial colonization, we developed and tested in an in-vitro study and animal study several antibacterial-coated ETTs (silver sulfadiazine with and without carbon in polyurethane, silver sulfadiazine and chlorhexidine with and without carbon in polyurethane, silver-platinum with and without carbon in polyurethane, chlorhexidine in polyurethane, and rose bengal for UV light). DESIGN, SETTING, ANIMALS, INTERVENTIONS: After preliminary studies, silver sulfadiazine in polyurethane (SSD-ETT) was selected among the coatings to be challenged every 24 h with 10(4)-10(6) Pseudomonas aeruginosa/ml and evaluated at 6 h, 24 h, and 72 h with standard microbiological studies, scanning electron microscopy, and confocal scanning microscopy. Subsequently, eight sheep were randomized to receive either a SSD-ETT or a standard ETT (St-ETT). After 24 h of mechanical ventilation, standard microbiological studies were performed together with scanning electron microscopy and confocal microscopy. In the in-vitro study SSD-ETT remained bacteria-free for up to 72 h, whereas St-ETT showed heavy P. aeruginosa growth and biofilm formation (p < 0.01). In sheep, the SSD-ETT group showed no bacterial growth in the ETT, ventilator tubing, and lower respiratory tract, while heavy colonization was found in the St-ETT (p < 0.01), ventilator tubing (p=0.03), and lower respiratory tract (p < 0.01). This study describes several effective and durable antibacterial coatings for ETTs. Particularly, SSD-ETT showed prevention against P. aeruginosa biofilm formation in a 72-h in-vitro study and lower respiratory tract colonization in sheep mechanically ventilated for 24 h.

The mitochondrial DNA landscape of modern Mexico

With more than 180 ethnic and linguistics groups, Mexico is a rich source for anthropological and population studies. This country witnessed the rise and fall of major civilizations, including the well-known Maya and Aztec civilizations, but as a result of heavy European colonization and influx, the population landscape has dramatically changed over the past five centuries. Today less than 30% of modern Mexicans identify themselves as being fully or partly Amerindians and the remaining population seems to have very little in common with their pre-Columbian ancestors. However, this is not the case when the maternal genetic component is evaluated in detail. Analysis of the mitochondrial DNA (mtDNA) control region sequences, including HVS-I, HVS-II and HVS-III, from more than 2,000 subjects revealed an overwhelming Native American legacy in the modern Mexican population, with ~90% of mtDNAs belonging to the four major pan-American haplogroups A2, B2, C1 and D1. This finding supports a European contribution to the Mexican gene pool primarily by male settlers and confirms the effectiveness of employing the uniparentally-transmitted mtDNA as a tool to reconstruct a country's history. Agreement was received from the authors to translate this paper into Chinese.

Index of Suspicion in the Nursery

Index of Suspicion in the Nursery

Widespread Environmental Contamination Associated With Patients With Diarrhea and Methicillin-ResistantStaphylococcusaureus Colonization of the Gastrointestinal Tract

Patients colonized with methicillin-resistant Staphylococcus aureus (MRSA) may contaminate their immediate environment with this organism. However, the extent to which gastrointestinal colonization with MRSA affects environmental contamination is not known. We investigated the frequency of environmental contamination in the rooms of patients with diarrheal stools and heavy gastrointestinal colonization with MRSA. Prospective observational study. A 500-bed teaching hospital. Stool specimens submitted for Clostridium difficile toxin assays were inoculated onto colistin-naladixic acid agar. MRSA was identified with standard methods. Samples from a standardized list of 10 environmental surfaces were cultured, from the rooms of 8 patients who had diarrhea that yielded heavy growth of MRSA (case patients) and from the rooms of 6 MRSA-positive patients with stool cultures negative for MRSA (control patients). MRSA isolates from 13 patients (8 case patients and 5 control patients) and 64 of the environmental isolates recovered from their rooms were compared by pulsed-field gel electrophoresis (PFGE). One clinical isolate from a control patient was excluded because there was no corresponding environmental MRSA isolate with which to compare it. Overall, MRSA were recovered from 47 (58.8%) of 80 surfaces in the rooms of case patients, compared with 14 (23.3%) of 60 surfaces in the rooms of control patients (58.8% [95% CI, 47.8-68.9] vs 23.3% [95% CI, 14.3-35.5]; P<.0001). The items most commonly contaminated were bedside rails, blood pressure cuffs, television remote controls, and toilet seats. Seventy-eight percent of the environmental isolates in patients' rooms had PFGE types that were indistinguishable or closely related to those recovered from the patients' clinical specimens. Patients who have diarrheal stools and heavy gastrointestinal colonization with MRSA are associated with significantly greater environmental MRSA contamination than patients without MRSA in their stool, and they are likely to be the source of that contamination.

Questions linked to Toya SP, Schraufnagel DE, Tzelepis GE. Candiduria in intensive care units: association with heavy colonization and candidaemia. J Hosp Infect 2007; 66:201–206.

Questions linked to Toya SP, Schraufnagel DE, Tzelepis GE. Candiduria in intensive care units: association with heavy colonization and candidaemia. J Hosp Infect 2007; 66:201–206.