Mycobacteriophages to Treat Tuberculosis: Dream or Delusion?

Rates of antimicrobial resistance are increasing globally while the pipeline of new antibiotics is drying up, putting patients with disease caused by drug-resistant bacteria at increased risk of complications and death. The growing costs for diagnosis and management of drug resistance threaten tuberculosis control where the disease is endemic and resources limited. Bacteriophages are viruses that attack bacteria. Phage preparations served as anti-infective agents long before antibiotics were discovered. Though small in size, phages are the most abundant and diverse biological entity on earth. Phages have co-evolved with their hosts and possess all the tools needed to infect and kill bacteria, independent of drug resistance. Modern biotechnology has improved our understanding of the biology of phages and their possible uses. Phage preparations are available to treat meat, fruit, vegetables, and dairy products against parasites or to prevent contamination with human pathogens, such as Listeria monocytogenes, Escherichia coli, or Staphylococcus aureus. Such phage-treated products are considered fit for human consumption. A number of recent case reports describe in great detail the successful treatment of highly drug-resistant infections with individualized phage preparations. Formal clinical trials with standardized products are slowly emerging. With its highly conserved genome and relative paucity of natural phage defence mechanisms Mycobacterium tuberculosis appears to be a suitable target for phage treatment. A phage cocktail with diverse and strictly lytic phages that kill all lineages of M. tuberculosis, and can be propagated on Mycobacterium smegmatis, has been assembled and is available for the evaluation of optimal dosage and suitable routes of administration for tuberculosis in humans. Phage treatment can be expected to be safe and active on extracellular organisms, but phage penetration to intracellular and granulomatous environments as well as synergistic effects with antibiotics are important questions to address during further evaluation.

Mycobacterium abscessus Strain Morphotype Determines Phage Susceptibility, the Repertoire of Therapeutically Useful Phages, and Phage Resistance.

Mycobacterium abscessus is an opportunistic pathogen whose treatment is confounded by widespread multidrug resistance. The therapeutic use of bacteriophages against Mycobacterium abscessus infections offers a potential alternative approach, although the spectrum of phage susceptibilities among M. abscessus isolates is not known. We determined the phage infection profiles of 82 M. abscessus recent clinical isolates and find that colony morphotype-rough or smooth-is a key indicator of phage susceptibility. None of the smooth strains are efficiently killed by any phages, whereas 80% of rough strains are infected and efficiently killed by at least one phage. The repertoire of phages available for potential therapy of rough morphotype infections includes those with relatively broad host ranges, host range mutants of Mycobacterium smegmatis phages, and lytically propagated viruses derived from integrated prophages. The rough colony morphotype results from indels in the glycopeptidolipid synthesis genes mps1 and mps2, negating reversion to smooth as a common route to phage resistance. Resistance is thus rare, and although mutations in polyketide synthesis, uvrD2, and rpoZ can confer resistance, these likely also impair survival in vivo The expanded therapeutic repertoire and the resistance profiles show that small cocktails or single phages could be suitable for controlling infections with rough strains.IMPORTANCEMycobacterium abscessus infections in cystic fibrosis patients are challenging to treat due to widespread antibiotic resistance. The therapeutic use of lytic bacteriophages presents a new potential strategy, but the great variation among clinical M. abscessus isolates demands determination of phage susceptibility prior to therapy. Elucidation of the variation in phage infection and factors determining it, expansion of the suite of therapeutic phage candidates, and a greater understanding of phage resistance mechanisms substantially advances the potential for broad implementation of new therapeutic options for M. abscessus infections.

Serum levels of neutrophil Gelatinase associated Lipocalin (NGAL) predicts hemodialysis after coronary angiography in high risk patients with acute coronary syndrome.

BACKGROUND: Contrast-induced nephropathy (CIN) following a percutaneous coronary intervention (PCI) is the third most common cause of acute kidney injury (AKI) worldwide. Patients who require hemodialysis secondary to CIN have an elevated mortality rate as high as 55%. The current definition of CIN is based on an elevation of creatinine and decrease in urinary output. Creatinine typically increases 48 h after the contrast exposure, which delays the diagnosis and treatment of CIN. The neutrophil gelatinase associated lipocalin (NGAL) has emerged as a sensitive and specific biomarker of renal injury. Limited data exists about the effectiveness of NGAL to predict CIN in high-risk patients with acute coronary syndrome (ACS) that underwent PCI. The primary aim of this study was to determine the association of serum NGAL levels and the need for hemodialysis after PCI. METHODS: This is a prospective, observational study. NGAL levels were measured using ELISA. Blood samples were obtained within the first 6 h of hospital admission, and 12 and 24 h after contrast exposure from angiography. The primary outcome was the requirement of hemodialysis. The non-parametric Mann-Whitney U test was used to test for differences in median serum levels of NGAL. A receiver operating characteristic (ROC) curve was developed to assess the accuracy of NGAL to predict the need for hemodialysis after PCI. RESULTS: A total of 2875 were screened; however, 45 patients with ACS that underwent PCI were included. All patients were at high risk of developing CIN defined by Mehran score > 11 points. The median (IQR) serum concentration of NGAL was significantly higher in patients that required versus did not require hemodialysis (340 [83-384] vs. 169 [100-210], p = 0.01). Elevated serum levels of NGAL with a cut-off at 6 h post PCI of 281 mg/dL predicted the need for hemodialysis with an area under the curve of 0.86 (95% CI, 0.66-1.00). CONCLUSIONS: In patients with ACS undergoing PCI; and high risk of developing CIN, an elevated serum level of NGAL 6 h after contrast exposure predicts the development of acute kidney injury requiring hemodialysis.

Engineered bacteriophages for treatment of a patient with a disseminated drug-resistant Mycobacterium abscessus.

A 15-year-old patient with cystic fibrosis with a disseminated Mycobacterium abscessus infection was treated with a three-phage cocktail following bilateral lung transplantation. Effective lytic phage derivatives that efficiently kill the infectious M. abscessus strain were developed by genome engineering and forward genetics. Intravenous phage treatment was well tolerated and associated with objective clinical improvement, including sternal wound closure, improved liver function, and substantial resolution of infected skin nodules.

Prophage-mediated defence against viral attack and viral counter-defence.

Temperate phages are common, and prophages are abundant residents of sequenced bacterial genomes. Mycobacteriophages are viruses that infect mycobacterial hosts including Mycobacterium tuberculosis and Mycobacterium smegmatis, encompass substantial genetic diversity and are commonly temperate. Characterization of ten Cluster N temperate mycobacteriophages revealed at least five distinct prophage-expressed viral defence systems that interfere with the infection of lytic and temperate phages that are either closely related (homotypic defence) or unrelated (heterotypic defence) to the prophage. Target specificity is unpredictable, ranging from a single target phage to one-third of those tested. The defence systems include a single-subunit restriction system, a heterotypic exclusion system and a predicted (p)ppGpp synthetase, which blocks lytic phage growth, promotes bacterial survival and enables efficient lysogeny. The predicted (p)ppGpp synthetase coded by the Phrann prophage defends against phage Tweety infection, but Tweety codes for a tetrapeptide repeat protein, gp54, which acts as a highly effective counter-defence system. Prophage-mediated viral defence offers an efficient mechanism for bacterial success in host-virus dynamics, and counter-defence promotes phage co-evolution.

Endothelial adhesion molecules and multiple organ failure in patients with severe sepsis.

OBJECTIVE: To determine if serum levels of endothelial adhesion molecules were associated with the development of multiple organ failure (MOF) and in-hospital mortality in adult patients with severe sepsis. DESIGN: This study was a secondary data analysis of a prospective cohort study. SETTING: Patients were admitted to two tertiary intensive care units in San Antonio, TX, between 2007 and 2012. PATIENTS: Patients with severe sepsis at the time of intensive care unit (ICU) admission were enrolled. Inclusion criteria were consistent with previously published criteria for severe sepsis or septic shock in adults. Exclusion criteria included immunosuppressive medications or conditions. INTERVENTIONS: None. MEASUREMENTS: Baseline serum levels of the following endothelial cell adhesion molecules were measured within the first 72h of ICU admission: Intracellular Adhesion Molecule 1 (ICAM-1), Vascular Cell Adhesion Molecule-1 (VCAM-1), and Vascular Endothelial Growth Factor (VEGF). The primary and secondary outcomes were development of MOF (⩾2 organ dysfunction) and in-hospital mortality, respectively. MAIN RESULTS: Forty-eight patients were enrolled in this study, of which 29 (60%) developed MOF. Patients that developed MOF had higher levels of VCAM-1 (p=0.01) and ICAM-1 (p=0.01), but not VEGF (p=0.70) compared with patients without MOF (single organ failure only). The area under the curve (AUC) to predict MOF according to VCAM-1, ICAM-1 and VEGF was 0.71, 0.73, and 0.54, respectively. Only increased VCAM-1 levels were associated with in-hospital mortality (p=0.03). These associations were maintained even after adjusting for APACHE and SOFA scores using logistic regression. CONCLUSIONS: High levels of serum ICAM-1 was associated with the development of MOF. High levels of VCAM-1 was associated with both MOF and in-hospital mortality.

Seudoquiste óseo hemorrágico o traumático: aporte al diagnóstico diferencial por imagen / Hemorrhagic or traumatic bone pseudocyst: a contribution to the differential diagnostic imaging

Al abordar el estudio de la patología maxilar, existe un capítulo, de difícil diagnóstico preciso. Este corresponde al de las lesiones seudoquísticas intraóseas, denominación sugerida a partir de su análisis histopatológico, el cual demostró que su morfología histológica no respetaba el patrón quístico. Es de naturaleza no odontogénica y se caracteriza por el compromiso de oras piezas óseas. Reportamos un caso con diagnóstico clínico de quiste traumático, confirmado por histopatología. Su hallazgo fue casual por encontrarse el paciente bajo un tratamiento paralelo