Complete genomic sequences of Propionibacterium freudenreichii phages from Swiss cheese reveal greater diversity than Cutibacterium (formerly Propionibacterium) acnes phages.

BACKGROUND: A remarkable exception to the large genetic diversity often observed for bacteriophages infecting a specific bacterial host was found for the Cutibacterium acnes (formerly Propionibacterium acnes) phages, which are highly homogeneous. Phages infecting the related species, which is also a member of the Propionibacteriaceae family, Propionibacterium freudenreichii, a bacterium used in production of Swiss-type cheeses, have also been described and are common contaminants of the cheese manufacturing process. However, little is known about their genetic composition and diversity. RESULTS: We obtained seven independently isolated bacteriophages that infect P. freudenreichii from Swiss-type cheese samples, and determined their complete genome sequences. These data revealed that all seven phage isolates are of similar genomic length and GC% content, but their genomes are highly diverse, including genes encoding the capsid, tape measure, and tail proteins. In contrast to C. acnes phages, all P. freudenreichii phage genomes encode a putative integrase protein, suggesting they are capable of lysogenic growth. This is supported by the finding of related prophages in some P. freudenreichii strains. The seven phages could further be distinguished as belonging to two distinct genomic types, or 'clusters', based on nucleotide sequences, and host range analyses conducted on a collection of P. freudenreichii strains show a higher degree of host specificity than is observed for the C. acnes phages. CONCLUSIONS: Overall, our data demonstrate P. freudenreichii bacteriophages are distinct from C. acnes phages, as evidenced by their higher genetic diversity, potential for lysogenic growth, and more restricted host ranges. This suggests substantial differences in the evolution of these related species from the Propionibacteriaceae family and their phages, which is potentially related to their distinct environmental niches.

Functional requirements for bacteriophage growth: gene essentiality and expression in mycobacteriophage Giles.

Bacteriophages represent a majority of all life forms, and the vast, dynamic population with early origins is reflected in their enormous genetic diversity. A large number of bacteriophage genomes have been sequenced. They are replete with novel genes without known relatives. We know little about their functions, which genes are required for lytic growth, and how they are expressed. Furthermore, the diversity is such that even genes with required functions - such as virion proteins and repressors - cannot always be recognized. Here we describe a functional genomic dissection of mycobacteriophage Giles, in which the virion proteins are identified, genes required for lytic growth are determined, the repressor is identified, and the transcription patterns determined. We find that although all of the predicted phage genes are expressed either in lysogeny or in lytic growth, 45% of the predicted genes are non-essential for lytic growth. We also describe genes required for DNA replication, show that recombination is required for lytic growth, and that Giles encodes a novel repressor. RNAseq analysis reveals abundant expression of a small non-coding RNA in a lysogen and in late lytic growth, although it is non-essential for lytic growth and does not alter lysogeny.

Umbilical artery Thrombosis: A case report of prenatal diagnosis and systematic review of the literature.

Umbilical Artery Thrombosis (UAT) is an extremely rare complication of pregnancy strongly associated with severe fetal distress and death. The pathogenesis is still unclear but it is often associated with anatomical cord abnormalities that leads to blood stasis and thrombosis formation. Other possible risk factors are maternal thrombophilia, autoimmune disease, gestational diabetes, hypertension disorders of pregnancy and Rh-alloimmunization. The most common clinical symptom is the reduction of fetal movements. The diagnosis is histopathological, but it can be suspected by clinical and prenatal ultrasound findings. Generally, the first choice therapy is the immediate delivery with cesarean section. This study reported a case of a spontaneous intrauterine UAT in a low-risk pregnancy and a systematic review of the literature on clinical, ultrasound and histopathological findings of UAT, in order to help clinicians in the diagnostic process and management of this rare complication.

Putative pseudolysogeny-dependent phage gene implicated in the superinfection resistance of Cutibacterium acnes.

Objectives: Cutibacterium acnes, formerly Propionibacterium acnes, is a bacterial species characterized by tenacious acne-contributing pathogenic strains. Therefore, bacteriophage therapy has become an attractive treatment route to circumvent issues such as evolved bacterial antibiotic resistance. However, medical and commercial use of phage therapy for C. acnes has been elusive, necessitating ongoing exploration of phage characteristics that confer bactericidal capacity. Methods: A novel phage (Aquarius) was isolated and analyzed. Testing included genomic sequencing and annotation, electron microscopy, patch testing, reinfection assays, and qPCR to confirm pseudolysogeny and putative superinfection exclusion (SIE) protein expression. Results: Given a superinfection-resistant phenotype was observed, reinfection assays and patch tests were performed, which confirmed the re-cultured bacteria were resistant to superinfection. Subsequent qPCR indicated pseudolysogeny was a concomitantly present phenomenon. Phage genomic analysis identified the presence of a conserved gene (gp41) with a product containing Ltp family-like protein signatures which may contribute to phage-mediated bacterial superinfection resistance (SIR) in a pseudolysogeny-dependent manner. qPCR was performed to analyze and roughly quantify gp41 activity, and mRNA expression was high during infection, implicating a role for the protein during the phage life cycle. Conclusions: This study confirms that C. acnes bacteria are capable of harboring phage pseudolysogens and suggests that this phenomenon plays a role in bacterial SIR. This mechanism may be conferred by the expression of phage proteins while the phage persists within the host in the pseudolysogenic state. This parameter must be considered in future endeavors for efficacious application of C. acnes phage-based therapeutics.

Hartford's gun buy-back program: are we on target?

Gunbuy-backprograms have been proposed as away to remove unwanted firearms from circulation, but remain controversial because their ability to prevent firearm injuries remains unproven. The purpose of this study is to describe the demographics of individuals participating in Connecticut's gun buy-backprogram in the context of annual gun sales and the epidemiology of firearm violence in the state. Over four years the buy-back program collected 464 firearms, including 232 handguns. In contrast, 91,602 firearms were sold in Connecticut during 2009 alone. The incidence of gun-related deaths was unchanged in the two years following the inception of the buy-back program. Suicide was associated with older age (mean = 51 +/- 18years) and Caucasian race (n = 539, 90%). Homicide was associated with younger age (mean = 30 +/- 12 years) and minority race (n = 425, 81%). A gun buy-back program alone is not likely to produce a measurable decrease in firearm injuries and deaths.

Robotic resection of a single adenoid cystic tumor liver metastasis using ICG fluorescence. A case report and literature review.

Adenoid cystic carcinoma (AdCC) is a rare tumor that typically develops in the salivary glands and less frequently in other sites of the head and neck region. Only a few cases of resected metachronous liver metastases have been reported. Minimally invasive surgery is currently the gold standard of care for liver resections; furthermore, the use of Indocyanine Green (ICG) is continuously increasing in surgical practice, especially in cases of primary liver tumors and colorectal liver metastases, due to its capacity to enhance liver nodules. We report the case of a 54-year-old male with a single liver metastasis of AdCC, located in SIII, who presented in our center 9 months after resection of a primary tumor of the laryngotracheal junction and adjuvant proton therapy. A 25-mg injection of ICG (0.3 mg/kg) was administered 48 h before surgery in order to highlight the tumor and perform an ICG-guided resection. The lesion was clearly visible during surgery, and, given its position and the proximity to the main lobar vessels of the left lobe, we opted for a left lateral sectionectomy. The outcome was unremarkable, with no major postoperative complications. The administration of ICG 48 h before surgery seems to be a valid tool even in cases of AdCC liver metastases, providing surgeons with better visualization of the lesion and improving the precision of the resection.

Fenoldopam Increases Urine Output in Oliguric Critically Ill Surgical Patients.

Background Fenoldopam is a short-acting dopamine A1 receptor agonist which mediates vasodilation of the renal arteries, thereby increasing urine output. The objective of this study was to compare the effects of fenoldopam and its synergistic effect on furosemide for improving the urine output in postoperative critically ill patients with acute kidney injury (AKI). Methods This is a retrospective study of postoperative critically ill patients with AKI. Patients who received furosemide (control group) were compared with those who received furosemide plus fenoldopam (treatment group) and evaluated at 12 and 24 hours post-treatment. Patients with oliguria and AKI were included in the study, while patients with chronic kidney disease (CKD) were excluded. Glomerular filtration rate, serum creatinine, blood pressure, calculated fluid accumulation, fluid intake, urine output, and total fluid output were used as variables to assess the medication effect. Results Of the 126 patients who met the inclusion and exclusion criteria, 87 patients received furosemide alone, and 39 patients received furosemide plus fenoldopam during their first 24 hours of admission to the surgical intensive care unit (SICU). Although not statistically significant, the addition of fenoldopam demonstrated an increase in mean urine output of 1525ml (IQR; 1530-2095) in the first 24 hours (P=0.06). There was also noted an increase in the urine output (p= 0.07) and a decrease in the total fluid accumulation when fenoldopam was co-administered with furosemide when compared to the patients who were only treated with furosemide (p=0.06). There was no significant change in creatinine clearance from baseline in either group.  Conclusion Fenoldopam may increase urine output in postoperative critically ill patients with acute kidney injury when administered within the first 24 hours of presentation. Based on our results, fenoldopam appears to have a synergistic effect with furosemide in our study population.

The role of the comprehensive complication index for the prediction of survival after liver transplantation.

In the last years, several scoring systems based on pre- and post-transplant parameters have been developed to predict early post-LT graft function. However, some of them showed poor diagnostic abilities. This study aims to evaluate the role of the comprehensive complication index (CCI) as a useful scoring system for accurately predicting 90-day and 1-year graft loss after liver transplantation. A training set (n = 1262) and a validation set (n = 520) were obtained. The study was registered at https://www.ClinicalTrials.gov (ID: NCT03723317). CCI exhibited the best diagnostic performance for 90 days in the training (AUC = 0.94; p < 0.001) and Validation Sets (AUC = 0.77; p < 0.001) when compared to the BAR, D-MELD, MELD, and EAD scores. The cut-off value of 47.3 (third quartile) showed a diagnostic odds ratio of 48.3 and 7.0 in the two sets, respectively. As for 1-year graft loss, CCI showed good performances in the training (AUC = 0.88; p < 0.001) and validation sets (AUC = 0.75; p < 0.001). The threshold of 47.3 showed a diagnostic odds ratio of 21.0 and 5.4 in the two sets, respectively. All the other tested scores always showed AUCs < 0.70 in both the sets. CCI showed a good stratification ability in terms of graft loss rates in both the sets (log-rank p < 0.001). In the patients exceeding the CCI ninth decile, 1-year graft survival rates were only 0.7% and 23.1% in training and validation sets, respectively. CCI shows a very good diagnostic power for 90-day and 1-year graft loss in different sets of patients, indicating better accuracy with respect to other pre- and post-LT scores.Clinical Trial Notification: NCT03723317.

Genetic Manipulation of Lytic Bacteriophages with BRED: Bacteriophage Recombineering of Electroporated DNA.

We describe a recombineering-based method for the genetic manipulation of lytically replicating bacteriophages, focusing on mycobacteriophages. The approach utilizes recombineering-proficient strains of Mycobacterium smegmatis and employs a cotransformation strategy with purified phage genomic DNA and a mutagenic substrate, which selects for only those cells that are competent to take up DNA. The cotransformation method, combined with the high rates of recombination obtained in M. smegmatis recombineering strains, allows for the efficient and rapid generation of bacteriophage mutants.

Genomic characterization of mycobacteriophage Giles: evidence for phage acquisition of host DNA by illegitimate recombination.

A characteristic feature of bacteriophage genomes is that they are architecturally mosaic, with each individual genome representing a unique assemblage of individual exchangeable modules. Plausible mechanisms for generating mosaicism include homologous recombination at shared boundary sequences of module junctions, illegitimate recombination in a non-sequence-directed process, and site-specific recombination. Analysis of the novel mycobacteriophage Giles genome not only extends our current perspective on bacteriophage genetic diversity, with more than 60% of the genes unrelated to other mycobacteriophages, but offers novel insights into how mosaic genomes are created. In one example, the integration/excision cassette is atypically situated within the structural gene operon and could have moved there either by illegitimate recombination or more plausibly via integrase-mediated site-specific recombination. In a second example, a DNA segment has been recently acquired from the host bacterial chromosome by illegitimate recombination, providing further evidence that phage genomic mosaicism is generated by nontargeted recombination processes.

G2A Attenuates Propionibacterium acnes Induction of Inflammatory Cytokines in Human Monocytes.

BACKGROUND: Acne vulgaris is a disease of the pilosebaceous unit characterized by increased sebum production, hyperkeratinization, and immune responses to Propionibacterium acnes (PA). Here, we explore a possible mechanism by which a lipid receptor, G2A, regulates immune responses to a commensal bacterium. OBJECTIVE: To elucidate the inflammatory properties of G2A in monocytes in response to PA stimulation. Furthermore, our study sought to investigate pathways by which lipids modulate immune responses in response to PA. METHODS: Our studies focused on monocytes collected from human peripheral blood mononuclear cells, the monocytic cell line THP-1, and a lab strain of PA. Our studies involved the use of enzyme-linked immunosorbent, Western blot, reverse transcription polymerase chain reaction, small interfering RNA (siRNA), and microarray analysis of human acne lesions in the measurements of inflammatory markers. RESULTS: G2A gene expression is higher in acne lesions compared to normal skin and is inducible by the acne therapeutic, 13-cis-retinoic acid. In vitro, PA induces both the Toll-like receptor 2-dependent expression of G2A as well as the production of the G2A ligand, 9-hydroxyoctadecadienoic acid, from human monocytes. G2A gene knockdown through siRNA enhances PA stimulation of interleukin (IL)-6, IL-8, and IL-1ß possibly through increased activation of the ERK1/2 MAP kinase and nuclear factor kappa B p65 pathways. CONCLUSION: G2A may play a role in quelling inflammatory cytokine response to PA, revealing G2A as a potential attenuator of inflammatory response in a disease associated with a commensal bacterium.

A comparative study of primary and secondary hemifacial spasm.

BACKGROUND: Hemifacial spasm (HFS) is a common movement disorder. OBJECTIVE: To evaluate possible differences in the demographic and clinical features between primary and secondary HFS. DESIGN: In-person interview using a standardized questionnaire to collect demographic and clinical data. SETTING: A multicenter study that included patients with HFS attending 3 Italian academic centers. Patients Two hundred fourteen patients with HFS. MAIN OUTCOME MEASURE: A complete neurological examination assessed the current muscle distribution of spasm and the presence of synkinetic movements between upper and lower facial muscles. RESULTS: The study sample comprised 214 patients with HFS, 81 men and 133 women, having a mean +/- SD age of 65.9 +/- 12.3 years; 164 patients were classified as having primary HFS and 50 patients (48 postparalytic and 2 symptomatic cases) were classified as having secondary HFS. Patients with primary and those with secondary HFS had similar mean +/- SD ages at onset (54.9 +/- 13.5 vs 57.0 +/- 12.8 years), male-female ratios (63:101 vs 18:32), right-sided-left-sided HFS (77:86 [1 bilateral] vs 21:28 [1 bilateral]), and frequencies of familial cases (2.9% vs 2.0%), respectively. Most patients (65.0%) with primary HFS had initial symptoms of periocular muscle contractions alone and had subsequent involvement of the lower facial muscles. Most patients (72.0%) with secondary HFS reported initial involvement of the upper and lower facial muscles simultaneously. Signs of synkinesis were present in primary (43.3%) and secondary (58.0%) HFS. CONCLUSIONS: Patients with primary and those with secondary HFS share common demographic and clinical features, including sex distribution, age at onset, affected side of HFS, synkinesis, and rarity of familial cases. Signs of synkinesis were present in significant proportions of patients with primary or secondary HFS. The 2 forms differed in clinical presentation.

Early Amiodarone-Induced Pulmonary Toxicity after Endovascular Aneurysm Repair: A Case Report.

Amiodarone is an antiarrhythmic drug that has been commonly used to treat supraventricular and ventricular arrhythmias. This drug is an iodine-containing compound that tends to accumulate in several organs, including the lungs. Especially, its main metabolically active metabolite desethylamiodarone can adversely affect many organs. A very well-known severe complication of amiodarone therapy is the amiodarone-induced pulmonary toxicity. This article presents the case study of an 82-year-old male patient with acute amiodarone-induced pulmonary toxicity. The patient underwent endovascular aneurysm repair for rapidly increasing abdominal aortic aneurysm. During the postoperative period the patient developed rapid atrial fibrillation and amiodarone therapy was initiated. Subsequently, the patient went into acute respiratory failure and was requiring high supplemental oxygen support and a chest X-ray revealed bilateral pulmonary infiltrates. During the hospital course the patient required mechanical ventilator support. With discontinuation of amiodarone, supportive therapy and steroid treatment patient symptoms significantly improved. Amiodarone-induced pulmonary toxicity must be considered in the differential diagnosis of all patients on the medication with progressive or acute respiratory symptoms. Early discontinuation of amiodarone and aggressive corticosteroid therapy should be considered as a viable treatment strategy.

Application of BRED technology to construct recombinant D29 reporter phage expressing EGFP.

Bacteriophage Recombineering of Electroporated DNA (BRED) has been described for construction of gene deletion and point mutations in mycobacteriophages. Using BRED, we inserted a Phsp60-egfp cassette (1143 bp) into the mycobacteriophage D29 genome to construct a new reporter phage, which was used for detection of mycobacterial cells. The cassette was successfully inserted and recombinant mycobacteriophage purified. DNA sequencing of the cassette did not show any mutations even after several phage generations. Mycobacterium smegmatis mc(2) 155 cells were infected with D29::Phsp60-egfp (MOI of 10) and evaluated for EGFP expression by microscopy. Fluorescence was observed at around 2 h after infection, but dissipated in later times because of cell lysis. We attempted to construct a lysis-defective mutant by deleting the lysA gene, although we were unable to purify the mutant to homogeneity even with complementation. These observations demonstrate the ability of BRED to insert c. 1 kbp-sized DNA segments into mycobacteriophage genomes as a strategy for constructing new diagnostic reporter phages.

Avaliação da cavidade nasal de camundongos submetidos à exposição ao herbicida ácido 2, 4- diclorofenoxiacético / Evaluation of the nasal cavity mice submitted to the inhalation exposure to the herbicide 2, 4 - dichlorophenoxyacetic acid

No último ano, o Brasil apresentou um aumento de 190% na utilização de agrotóxicos, o que implica em um grave problema de saúde pública. O ácido 2,4-diclorofenoxiacético possui classificação toxicológica I (extremamente tóxico) e por ser muito volátil, favorece a contaminação de solos, águas, animais e seres humanos. Modelo do estudo: Estudo Experimental. Objetivo: Analisar o infiltrado inflamatório de camundongos submetidos à nebulização aguda ao herbicida ácido 2,4-diclorofenoxiacético, em diferentes intervalos de tempo e concentrações. Métodos: Foram utilizados 80 camundongos Swiss machos divididos em quatro grupos (n=20): salina, baixa (3,71 x 10-3 gramas de ingrediente ativo por hectare), média (6,19 x 10-3 gramas de ingrediente ativo por hectare) e alta concentração (9,28 x10-3 gramas de ingrediente ativo por hectare). Todos os animais foram expostos às nebulizações preconizadas para cada grupo por 15 minutos, em diferentes intervalos de tempo: 24, 48, 72 e 192 horas. O protocolo de exposição contou com duas caixas ligadas a um nebulizador ultrassônico e o vestíbulo nasal de cada animal foi retirado após a eutanásia, para a análise histológica. Resultados: A contagem de mastócitos apresentou valores significativamente aumentados no grupo alta concentração, no intervalo de tempo de 48 horas, quando comparado ao de 24 horas. Conclusão: Os resultados mostraram que a exposição aguda ao herbicida ácido 2,4-diclorofenoxiacético aumenta a produção de mastócitos na cavidade nasal de animais expostos a altas concentrações, e que podem estar relacionados ao surgimento de reações alérgicas. (AU)

In the last year, Brazil presented a 190% increase in the use of agrochemicals, which implies a serious public health problem. 2,4-Dichlorophenoxyacetic acid has toxicological classification I (extremely toxic) and because it is very volatile, it favors the contamination of soils, water, animals and humans. Study model: Experimental study. Objective: To analyze the inflammatory infiltrate of mice submitted to acute nebulization to the 2.4-dichlorophenoxyacetic acid herbicide at different time intervals and concentrations. Methods: Eighty Swiss male mice were divided into four groups (n=20): saline, low (3.71 x 10-3 grams of active ingredient per hectare), medium (6.19 x 10-3 grams of active ingredient per hectare) and high concentration (9.28 x 10-3 grams of active ingredient per hectare). All animals were exposed to the nebulizations proposed for each group, for 15 minutes, at different time intervals: 24, 48, 72 and 192 hours. The exposure protocol had two boxes attached to an ultrasonic nebulizer and the nasal vestibule of each animal was removed after euthanasia for histological analysis. Results: The mast cell count showed significantly increased values in the high concentration group, in the time interval of 48 hours, when compared to the 24-hour period. Conclusion: The results showed that the acute exposure to the herbicide 2,4-dichlorophenoxyacetic acid increases the production of mast cells in the nasal cavity of animals exposed to high concentrations, which may be related to the appearance of allergic reactions. (AU)

Recombineering: A powerful tool for modification of bacteriophage genomes.

Recombineering, a recently developed technique for efficient genetic manipulation of bacteria, is facilitated by phage-derived recombination proteins and has the advantage of using DNA substrates with short regions of homology. This system was first developed in E. coli but has since been adapted for use in other bacteria. It is now widely used in a number of different systems for a variety of purposes, and the construction of chromosomal gene knockouts, deletions, insertions, point mutations, as well as in vivo cloning, mutagenesis of bacterial artificial chromosomes and phasmids, and the construction of genomic libraries has been reported. However, these methods also can be effectively applied to the genetic modification of bacteriophage genomes, in both their prophage and lytically growing states. The ever-growing collection of fully sequenced bacteriophages raises more questions than they answer, including the unknown functions of vast numbers of genes with no known homologs and of unknown function. Recombineering of phage genomes is central to addressing these questions, enabling the simple construction of mutants, determination of gene essentiality, and elucidation of gene function. In turn, advances in our understanding of phage genomics should present similar recombineering tools for dissecting a multitude of other genetically naïve bacterial systems.

On the nature of mycobacteriophage diversity and host preference.

The complete genome sequences of over 220 mycobacteriophages reveal them to be highly diverse, with numerous types sharing little or no nucleotide sequence identity with each other. We have determined the preferences of these phages for Mycobacterium tuberculosis and for other strains of Mycobacterium smegmatis, and find there is a correlation between genome type (cluster, subcluster, singleton) and host range. For many of the phages, expansion of host range occurs at relatively high frequencies, and we describe several examples in which host constraints occur at early stages of infection (adsorption or DNA injection), and phages have the ability to expand their host range through mutations in tail genes. We present a model in which phage diversity is a function of both the ability of phages to rapidly adapt to new hosts and the richness of the diversity of the bacterial population from which those phages are isolated.

Propionibacterium acnes bacteriophages display limited genetic diversity and broad killing activity against bacterial skin isolates.

UNLABELLED: Investigation of the human microbiome has revealed diverse and complex microbial communities at distinct anatomic sites. The microbiome of the human sebaceous follicle provides a tractable model in which to study its dominant bacterial inhabitant, Propionibacterium acnes, which is thought to contribute to the pathogenesis of the human disease acne. To explore the diversity of the bacteriophages that infect P. acnes, 11 P. acnes phages were isolated from the sebaceous follicles of donors with healthy skin or acne and their genomes were sequenced. Comparative genomic analysis of the P. acnes phage population, which spans a 30-year temporal period and a broad geographic range, reveals striking similarity in terms of genome length, percent GC content, nucleotide identity (>85%), and gene content. This was unexpected, given the far-ranging diversity observed in virtually all other phage populations. Although the P. acnes phages display a broad host range against clinical isolates of P. acnes, two bacterial isolates were resistant to many of these phages. Moreover, the patterns of phage resistance correlate closely with the presence of clustered regularly interspaced short palindromic repeat elements in the bacteria that target a specific subset of phages, conferring a system of prokaryotic innate immunity. The limited diversity of the P. acnes bacteriophages, which may relate to the unique evolutionary constraints imposed by the lipid-rich anaerobic environment in which their bacterial hosts reside, points to the potential utility of phage-based antimicrobial therapy for acne. IMPORTANCE: Propionibacterium acnes is a dominant member of the skin microflora and has also been implicated in the pathogenesis of acne; however, little is known about the bacteriophages that coexist with and infect this bacterium. Here we present the novel genome sequences of 11 P. acnes phages, thereby substantially increasing the amount of available genomic information about this phage population. Surprisingly, we find that, unlike other well-studied bacteriophages, P. acnes phages are highly homogeneous and show a striking lack of genetic diversity, which is perhaps related to their unique and restricted habitat. They also share a broad ability to kill clinical isolates of P. acnes; phage resistance is not prevalent, but when detected, it appears to be conferred by chromosomally encoded immunity elements within the host genome. We believe that these phages display numerous features that would make them ideal candidates for the development of a phage-based therapy for acne.

Mycobacteriophages BPs, Angel and Halo: comparative genomics reveals a novel class of ultra-small mobile genetic elements.

Mycobacteriophages BPs, Angel and Halo are closely related viruses isolated from Mycobacterium smegmatis, and possess the smallest known mycobacteriophage genomes, 41,901 bp, 42,289 bp and 41,441 bp, respectively. Comparative genome analysis reveals a novel class of ultra-small mobile genetic elements; BPs and Halo each contain an insertion of the proposed mobile elements MPME1 and MPME2, respectively, at different locations, while Angel contains neither. The close similarity of the genomes provides a comparison of the pre- and post-integration sequences, revealing an unusual 6 bp insertion at one end of the element and no target duplication. Nine additional copies of these mobile elements are identified in a variety of different contexts in other mycobacteriophage genomes. In addition, BPs, Angel and Halo have an unusual lysogeny module in which the repressor and integrase genes are closely linked. The attP site is located within the repressor-coding region, such that prophage formation results in expression of a C-terminally truncated, but active, form of the repressor.