Photodynamic inactivation of biofilm: Taking a lightly colored approach to stubborn infection

Microbial biofilms are responsible for a variety of microbial infections in different parts of the body, such as urinary tract infections, catheter infections, middle-ear infections, gingivitis, caries, periodontitis, orthopedic implants, and so on. The microbial biofilm cells have properties and gene expression patterns distinct from planktonic cells, including phenotypic variations in enzymic activity, cell wall composition and surface structure, which increase the resistance to antibiotics and other antimicrobial treatments. There is consequently an urgent need for new approaches to attack biofilm-associated microorganisms, and antimicrobial photodynamic therapy (aPDT) may be a promising candidate. aPDT involves the combination of a nontoxic dye and low-intensity visible light which, in the presence of oxygen, produces cytotoxic reactive oxygen species. It has been demonstrated that many biofilms are susceptible to aPDT, particularly in dental disease. This review will focus on aspects of aPDT that are designed to increase efficiency against biofilms modalities to enhance penetration of photosensitizer into biofilm, and a combination of aPDT with biofilm-disrupting agents. © 2013 Informa UK Ltd.

Ureteroileal Strictures After Urinary Diversion with an Ileal Segment—Is There a Place for Endourological Treatment at All?

Purpose We compared the long-term results of minimally invasive endourological intervention and open surgical revision in patients with a nonmalignant ureteroileal stricture. Materials and Methods We retrospectively evaluated the records of 74 patients (85 renal units) treated for unilateral or bilateral nonmalignant ureteroileal strictures. Overall, 96 endourological and 35 open surgical procedures were performed. Balloon dilatation and Acucise® or Ho:YAG laser endoureterotomy were used as minimally invasive endourological interventions. Open surgical revision with stricture resection and open ureteroileal end-to-side-reanastomosis was the alternate therapy. Treatment success was defined as radiological normalization or improvement of upper urinary tract morphology combined with absent flank pain, infection, ureteral stents or percutaneous nephrostomies. Results Median followup was 29 months (range 2 to 177). The overall success rate was 26% (25 of 96 cases) for endourological intervention vs 91% (32 of 35) for open surgical revision (p <0.001). Subgroup analysis showed a significant difference in the success rate of minimally invasive endourological interventions vs open surgical revision for strictures greater than 1 cm (3 of 52 cases or 6% vs 19 of 22 or 86%, p <0.001). The success rate of endourological and open surgical procedures for strictures 1 cm or less was 50% (22 of 44 cases) and 100% (13 of 13), respectively. After adjusting for multiple preoperative stricture characteristics, only stricture length was strongly and inversely associated with a successful outcome (p <0.001). Conclusions Open surgical revision produces better results than minimally invasive endourological intervention for ureteroileal strictures, particularly those greater than 1 cm. The success rate of endourological intervention is acceptable only for ureteroileal strictures 1 cm or less. Therefore, ureteroileal strictures greater than 1 cm should be primarily managed by open surgical revision.

Bacteriophage Can Prevent Encrustation and Blockage of Urinary Catheters by Proteus mirabilis.

Proteus mirabilis forms dense crystalline biofilms on catheter surfaces that occlude urine flow, leading to serious clinical complications in long-term catheterized patients, but there are presently no truly effective approaches to control catheter blockage by this organism. This study evaluated the potential for bacteriophage therapy to control P. mirabilis infection and prevent catheter blockage. Representative in vitro models of the catheterized urinary tract, simulating a complete closed drainage system as used in clinical practice, were employed to evaluate the performance of phage therapy in preventing blockage. Models mimicking either an established infection or early colonization of the catheterized urinary tract were treated with a single dose of a 3-phage cocktail, and the impact on time taken for catheters to block, as well as levels of crystalline biofilm formation, was measured. In models of established infection, phage treatment significantly increased time taken for catheters to block (∼ 3-fold) compared to untreated controls. However, in models simulating early-stage infection, phage treatment eradicated P. mirabilis and prevented blockage entirely. Analysis of catheters from models of established infection 10 h after phage application demonstrated that phage significantly reduced crystalline biofilm formation but did not significantly reduce the level of planktonic cells in the residual bladder urine. Taken together, these results show that bacteriophage constitute a promising strategy for the prevention of catheter blockage but that methods to deliver phage in sufficient numbers and within a key therapeutic window (early infection) will also be important to the successful application of phage to this problem.

Role of the gp85/Trans-Sialidases in Trypanosoma cruzi Tissue Tropism: Preferential Binding of a Conserved Peptide Motif to the Vasculature In Vivo

Background: Transmitted by blood-sucking insects, the unicellular parasite Trypanosoma cruzi is the causative agent of Chagas' disease, a malady manifested in a variety of symptoms from heart disease to digestive and urinary tract dysfunctions. The reasons for such organ preference have been a matter of great interest in the field, particularly because the parasite can invade nearly every cell line and it can be found in most tissues following an infection. Among the molecular factors that contribute to virulence is a large multigene family of proteins known as gp85/trans-sialidase, which participates in cell attachment and invasion. But whether these proteins also contribute to tissue homing had not yet been investigated. Here, a combination of endothelial cell immortalization and phage display techniques has been used to investigate the role of gp85/trans-sialidase in binding to the vasculature. Methods: Bacteriophage expressing an important peptide motif (denominated FLY) common to all gp85/trans-sialidase proteins was used as a surrogate to investigate the interaction of this motif with the endothelium compartment. For that purpose phage particles were incubated with endothelial cells obtained from different organs or injected into mice intravenously and the number of phage particles bound to cells or tissues was determined. Binding of phages to intermediate filament proteins has also been studied. Findings and Conclusions: Our data indicate that FLY interacts with the endothelium in an organ-dependent manner with significantly higher avidity for the heart vasculature. Phage display results also show that FLY interaction with intermediate filament proteins is not limited to cytokeratin 18 (CK18), which may explain the wide variety of cells infected by the parasite. This is the first time that members of the intermediate filaments in general, constituted by a large group of ubiquitously expressed proteins, have been implicated in T. cruzi cell invasion and tissue homing.

Ampicillin/sulbactam compared with polymyxins for the treatment of infections caused by carbapenem-resistant Acinetobacter spp.

Background: There has been an increase in worldwide infections caused by carbapenem-resistant Acinetobacter. This poses a therapeutic challenge as few treatment options are available. Objectives: The aim of this study was to evaluate the efficacy and safety of polymyxins and ampicillin/sulbactam for treating infections caused by carbapenem-resistant Acinetobacter spp. and to evaluate prognostic factors. Methods: This was a retrospective review of patients from two teaching hospitals who had nosocomial infections caused by carbapenem-resistant Acinetobacter spp. from 1996 to 2004. Diagnosis of infection was based on CDC criteria plus the isolation of Acinetobacter from a usually sterile site or from bronchoalveolar lavage. Urinary tract infections were not included. Data on demographic and clinical features and treatment were collected from medical records. Prognostic factors associated with two outcomes (mortality during treatment and in-hospital mortality) were evaluated. Results: Eighty-two patients received polymyxins and 85 were treated with ampicillin/sulbactam. Multiple logistic regression analysis revealed that independent predictors of mortality during treatment were treatment with polymyxins, higher Acute Physiological and Chronic Health Evaluation II (APACHE II) score, septic shock, delay in starting treatment and renal failure. On multivariate analysis, prognostic factors for in-hospital mortality were older age, septic shock and higher APACHE II score. Conclusions: This is the first study comparing current therapeutic options for infections due to carbapenem-resistant Acinetobacter. The most important finding of the present study is that ampicillin/sulbactam appears to be more efficacious than polymyxins, which was an independent factor associated with mortality during treatment.

Frequency of human metapneumovirus infection in hematopoietic SCT recipients during 3 consecutive years

Respiratory viruses can cause significant morbidity in immunocompromised hosts. Human metapneumovirus (hMPV) has been increasingly associated with lower respiratory tract infection in hematopoietic SCT (HSCT) recipients, with mortality rates up to 50%. No data on the occurrence of hMPV infection in HSCT recipients have been reported in the southern hemisphere. We conducted a retrospective study including 228 nasal wash samples from 153 HSCT recipients with respiratory symptoms during 2001, 2002 and 2003. hMPV was detected by real-time PCR with primers complementary to the nucleocapsid region of hMPV genome. Eleven of the 153 patients (7.2%) acquired hMPV infection during the study period (6.4% in 2001, 4.7% in 2002 and 11.1% in 2003). Among the 11 HSCT recipients with hMPV infection, 1 died 8 days after the diagnosis, but the role of hMPV in the patient`s death could not be established. In 2001 and 2003, hMPV group A prevailed over group B. In 2002, both groups were detected equally. hMPV infections were diagnosed in late winter and spring. The frequency of hMPV infection in HSCT recipients living in Brazil was similar to those observed in the northern hemisphere. Sensitive techniques to detect hMPV should be included in the diagnostic assessment of HSCT recipients with respiratory symptoms.

Effectiveness of Oral Rinse with Chlorhexidine in Preventing Nosocomial Respiratory Tract Infections among Intensive Care Unit Patients

OBJECTIVE. To evaluate the effectiveness of the oral application of a 0.12% solution of chlorhexidine for prevention of respiratory tract infections among intensive care unit (ICU) patients. DESIGN. The study design was a double-blind, randomized, placebo-controlled trial. SETTING. The study was performed in an ICU in a tertiary care hospital at a public university. PATIENTS. Study participants comprised 194 patients admitted to the ICU with a prospective length of stay greater than 48 hours, randomized into 2 groups: those who received chlorhexidine (n = 98) and those who received a placebo (n = 96). INTERVENTION. Oral rinses with chlorhexidine or a placebo were performed 3 times a day throughout the duration of the patient`s stay in the ICU. Clinical data were collected prospectively. RESULTS. Both groups displayed similar baseline clinical features. The overall incidence of respiratory tract infections (RR, 1.0 [95% confidence interval [CI], 0.63-1.60]) and the rates of ventilator-associated pneumonia per 1,000 ventilator-days were similar in both experimental and control groups (22.6 vs 22.3; P = .95). Respiratory tract infection-free survival time (7.8 vs 6.9 days; P = .61), duration of mechanical ventilation (11.1 vs 11.0 days; P = .61), and length of stay (9.7 vs 10.4 days; P = .67) did not differ between the chlorhexidine and placebo groups. However, patients in the chlorhexidine group exhibited a larger interval between ICU admission and onset of the first respiratory tract infection (11.3 vs 7.6 days; P = .05). The chances of surviving the ICU stay were similar (RR, 1.08 [95% CI, 0.72-1.63]). CONCLUSION. Oral application of a 0.12% solution of chlorhexidine does not prevent respiratory tract infections among ICU patients, although it may retard their onset.

Drug targets and mechanisms of resistance in the anaerobic protozoa

The anaerobic protozoa Giardia duodenalis, Trichomonas vaginalis, and Entamoeba histolytica infect up to a billion people each year. G. duodenalis and E. histolytica are primarily pathogens of the intestinal tract, although E. histolytica can form abscesses and invade other organs, where it can be fatal if left untreated. T. vaginalis infection is a sexually transmitted infection causing vaginitis and acute inflammatory disease of the genital mucosa. T. vaginalis has also been reported in the urinary tract fallopian tubes, and pelvis and can cause pneumonia, bronchitis, and oral lesions. Respiratory infections can be acquired perinatally. T. vaginalis infections have been associated with preterm delivery, low birth weight, and increased mortality as well as predisposing to human immunodeficiency virus infection, AIDS, and cervical cancer. All three organisms lack mitochondria and are susceptible to the nitroimidazole metronidazole because of similar low-redox-potential anaerobic metabolic pathways. Resistance to metronidazole and other drugs has been observed clinically and in the laboratory. Laboratory studies have identified the enzyme that activates metronidazole, pyruvate:ferredoxin oxidoreductase, to its nitroso form and distinct mechanisms of decreasing drug susceptibility that are induced in each organism. Although the nitroimidazoles have been the drug family of choice for treating the anaerobic protozoa, G. duodenalis is less susceptible to other antiparasitic drugs, such as furazolidone, albendazole, and quinacrine. Resistance has been demonstrated for each agent and the mechanism of resistance has been investigated. Metronidazole resistance in T. vaginalis is well documented, and the principal mechanisms have been defined Bypass metabolism, such as alternative oxidoreductases, have been discovered in both organisms. Aerobic versus anaerobic resistance in T. vaginalis is discussed. Mechanisms of metronidazole resistance in E. histolytica have recently been investigated ruing laboratory-induced resistant isolates. Instead of downregulation of the pyruvate:ferredoxin oxidoreductase and ferredoxin pathway as seen in G. duodenalis and T. vaginalis, E. histolytica induces oxidative stress mechanisms, including superoxide dismutase and peroxiredoxin. The review examines the value of investigating both clinical and laboratory-induced syngeneic drug-resistant isolates and dissection of the complementary data obtained. Comparison of resistance mechanisms in anaerobic bacteria and the parasitic protozoa is discussed as well as the value of studies of the epidemiology of resistance.

Infection and childhood leukemia: review of evidence

OBJECTIVE : To analyze studies that evaluated the role of infections as well as indirect measures of exposure to infection in the risk of childhood leukemia, particularly acute lymphoblastic leukemia. METHODS : A search in Medline, Lilacs, and SciELO scientific publication databases initially using the descriptors “childhood leukemia” and “infection” and later searching for the words “childhood leukemia” and “maternal infection or disease” or “breastfeeding” or “daycare attendance” or “vaccination” resulted in 62 publications that met the following inclusion criteria: subject aged ≤ 15 years; specific analysis of cases diagnosed with acute lymphoblastic leukemia or total leukemia; exposure assessment of mothers’ or infants’ to infections (or proxy of infection), and risk of leukemia. RESULTS : Overall, 23 studies that assessed infections in children support the hypothesis that occurrence of infection during early childhood reduces the risk of leukemia, but there are disagreements within and between studies. The evaluation of exposure to infection by indirect measures showed evidence of reduced risk of leukemia associated mainly with daycare attendance. More than 50.0% of the 16 studies that assessed maternal exposure to infection observed increased risk of leukemia associated with episodes of influenza, pneumonia, chickenpox, herpes zoster, lower genital tract infection, skin disease, sexually transmitted diseases, Epstein-Barr virus, and Helicobacter pylori . CONCLUSIONS : Although no specific infectious agent has been identified, scientific evidence suggests that exposure to infections has some effect on childhood leukemia etiology.

Tuberculosis in renal transplant patients

Tuberculosis (TB) was diagnosed in 25 of 466 patients who underwent renal transplant over a period of 15 years. TB developed from 1 month to 9 years post-transplant. In 56% of the cases the onset was within the first post-transplant year. TB affected several isolated or combined organs. Pulmonary involvement was present in 76% of cases, either as isolated pleuro-pulmonary (56%) or associated with other sites (20%). The non-pulmonary sites were: skin, joints, tests, urinary tract, central nervous system and lymphonodules. The diagnosis was confirmed by biopsy in 64% of the cases, by identification of tubercle bacilli in 24% and only at necropsy in 12% Biopsy specimens could be classified in three histological forms: exudative, that occurred in early onset and more severe cases granulomatous in late onset and benign cases; and mixed in intermediate cases. Azathioprine dosages were similar along post-transplant time periods in TB patients and in the control groups; and in TB patients who were cured and who died. The number of steroid treated rejection crises was greater in TB than in the control group. Prednisone doses were higher and the number of rejection crises was greater in TB patients who died than in those who were cured. Fifteen patients were cured and ten died, two of them of causes unrelated to TB. Six of the eight TB-related deaths occurred in the first 6 post-transplant months. The outcome was poor in patients in whom TB arose early in post-transplant period and where the exudative or mixed forms were present; whereas the prognosis was good in patients with late onset and granulomatous form of TB. In one patient TB was transmitted by the allograft.

Infective endocarditis (IE) first diagnosed at autopsy: analysis of 31 cases in Ribeirão Preto, Brazil

Thirty one infective endocarditis (IE) fatal cases whose diagnosis was first obtained at autopsy were studied. The clinical data of these patients (Group 1) showed significant differences compared to other 141 IE cases (Group 2). The average age of 53 years in Group 1 patients was 18 years higher than that of Group 2. The Group 1 patients had a low frequency of IE predisposing heart disease. Both patient groups presented fever (about 87%), but a significant low frequency of cardiac murmur (25.8%) was observed in Group 1 patients and echocardiography tests were performed in only 16.1%, suggesting that IE diagnosis was not suspected. Likewise, although most Group 1 patients appeared with severe acute illness, they did not present the classic IE clinical presentation. Blood cultures were performed in only 64.5% of the Group 1 patients. However, bacteria were isolated in 70% of these blood cultures and Staphylococcus aureus was isolated in 71.4%. The bacteria attacked mitral and aortic valves. Complications such as embolizations and cardiac failure occurred in almost half of the cases and they also presented with infections of the lungs, urinary tract, and central nervous system. Medical procedures were performed in practically all fatal cases whose diagnosis was first obtained at autopsy. Sepsis occurred in about half of the patients and it was followed by shock in more than 25%. This form of IE must be suspected in mature and in old febrile hospitalized patients having infection predisposing diseases, embolization, and suffering medical procedures.

Embolisation of Prostatic Arteries as Treatment of Moderate to Severe Lower Urinary Symptoms (LUTS) Secondary to Benign Hyperplasia: Results of Short- and Mid-Term Follow-Up

OBJECTIVES: To evaluate the short- and medium-term results of prostatic arterial embolisation (PAE) for benign prostatic hyperplasia (BPH). METHODS: This was a prospective non-randomised study including 255 patients diagnosed with BPH and moderate to severe lower urinary tract symptoms after failure of medical treatment for at least 6 months. The patients underwent PAE between March 2009 and April 2012. Technical success is when selective prostatic arterial embolisation is completed in at least one pelvic side. Clinical success was defined as improving symptoms and quality of life. Evaluation was performed before PAE and at 1, 3, 6 and every 6 months thereafter with the International Prostate Symptom Score (IPSS), quality of life (QoL), International Index of Erectile Function (IIEF), uroflowmetry, prostatic specific antigen (PSA) and volume. Non-spherical polyvinyl alcohol particles were used. RESULTS: PAE was technically successful in 250 patients (97.9 %). Mean follow-up, in 238 patients, was 10 months (range 1-36). Cumulative rates of clinical success were 81.9 %, 80.7 %, 77.9 %, 75.2 %, 72.0 %, 72.0 %, 72.0 % and 72.0 % at 1, 3, 6, 12, 18, 24, 30 and 36 months, respectively. There was one major complication. CONCLUSIONS: PAE is a procedure with good results for BPH patients with moderate to severe LUTS after failure of medical therapy. KEY POINTS: • Prostatic artery embolisation offers minimally invasive therapy for benign prostatic hyperplasia. • Prostatic artery embolisation is a challenging procedure because of vascular anatomical variations. • PAE is a promising new technique that has shown good results.

Non-clinical isolates bring new findings on enterococcal virulence

Dissertation presented to obtain the PhD degree in Biology

The Intensive Care Global Study on Severe Acute Respiratory Infection (IC-GLOSSARI): a Multicenter, Multinational, 14-Day Inception Cohort Study

PURPOSE: In this prospective, multicenter, 14-day inception cohort study, we investigated the epidemiology, patterns of infections, and outcome in patients admitted to the intensive care unit (ICU) as a result of severe acute respiratory infections (SARIs). METHODS: All patients admitted to one of 206 participating ICUs during two study weeks, one in November 2013 and the other in January 2014, were screened. SARI was defined as possible, probable, or microbiologically confirmed respiratory tract infection with recent onset dyspnea and/or fever. The primary outcome parameter was in-hospital mortality within 60 days of admission to the ICU. RESULTS: Among the 5550 patients admitted during the study periods, 663 (11.9 %) had SARI. On admission to the ICU, Gram-positive and Gram-negative bacteria were found in 29.6 and 26.2 % of SARI patients but rarely atypical bacteria (1.0 %); viruses were present in 7.7 % of patients. Organ failure occurred in 74.7 % of patients in the ICU, mostly respiratory (53.8 %), cardiovascular (44.5 %), and renal (44.6 %). ICU and in-hospital mortality rates in patients with SARI were 20.2 and 27.2 %, respectively. In multivariable analysis, older age, greater severity scores at ICU admission, and hematologic malignancy or liver disease were independently associated with an increased risk of in-hospital death, whereas influenza vaccination prior to ICU admission and adequate antibiotic administration on ICU admission were associated with a lower risk. CONCLUSIONS: Admission to the ICU for SARI is common and associated with high morbidity and mortality rates. We identified several risk factors for in-hospital death that may be useful for risk stratification in these patients.

Megabladder in experimental Chagas disease: pathological features of the bladder wall

Mega-organs, primarily in the digestive tract, are well known to occur in chronic Chagas disease. Acute experimental infection with Trypanosoma cruzi results in parasitism of a wide range of cells, tissues, and organs, including the urinary bladder. Infection of BALB/c mice with 100,000 bloodstream forms of the Y strain of T. cruzi induced acute infection with intense parasitism of all layers of the urinary bladder. Parasites were found in the mucosa, lamina propria, muscular, adventitial connective, and fat tissue. Desquamate epithelial cells with amastigotes in the bladder lumen were also found. After 60 days of infection, mice inoculated with 50 bloodstream forms developed dilated, thin-walled bladders that had inflammatory infiltrates and foci of fibrosis replacing areas of damaged muscular layer. These lesions result from direct damage to the muscle fibers by the T. cruzi, leading to myosites, muscle damage, and scarring. Direct damage of paraganglia cells secondary to parasitism, leading to dilatation, damage of muscle fibers, and scarring with replacement of muscular tissue with connective tissue, should also be considered as a cause of functional disturbance of the urinary bladder.