Isolation and characterization of Stenotrophomonas maltophilia phages active against clinical strains / Maxine Monoyer

Public ISBD Titre : Isolation and characterization of Stenotrophomonas maltophilia phages active against clinical strains Type de document : TFE / Mémoire Auteurs : Maxine Monoyer ; Nicolas Kesteman, Directeur de la recherche Editeur : Montignies-sur-Sambre : Helha. Paramédical - Biologie médicale Année de publication : 2024 Note générale : Le fichier numérique de ce document est disponible uniquement pour les membres de la Haute Ecole Louvain-en-Hainaut ainsi que ses étudiants. Veuillez-vous connecter pour accéder à votre compte lecteur Langues : Anglais (eng) Index. décimale : TFE Bio Med TFE Biologie médicale Résumé : This study investigates the isolation and characterization of phages active against clinical strains of Stenotrophomonas maltophilia. This opportunistic bacteria present significant treatment challenges due to its resistance to antibiotics. The research objective was to identify new phages with a lytic activity on several clinical strains of S.maltophilia to use in combination with antibiotic treatment. Phages were isolated from two different sewage water samples then purified after five rounds to be propagate after and titrated to know the concentration of phages. Out of the initial samples, 9 phages were successfully isolated and demonstrated distinct plaque morphology. Their efficacity was evaluated against clinical strains and showed that several phages exhibited significant lytic activity against those strains. Additionally, the study explored the activity of phages on bacteria using an automated system called Omnilog that measures the cell respiration. Those tests showed that some phages delay the bacterial growth of a few hours. Further tests were made, using a combination of phage on a strain bit it did not enhance activity of the phages on the strain. The activity of a phage was also tested in combination with an antibiotic, Ciprofloxacin, and resulted in complete inhibition of bacterial growth whilst the antibiotic alone only delayed growth. Another test was made using another phage in combination with Ciprofloxacin on another strain and did not show a better activity on the strain of the phage in combination with antibiotic than the antibiotic alone. This dual approach, using phage and antibiotics, could be a more effective strategy to treat resistant bacterial infections. This study underscores the importance of further explorations of phage and antibiotics combinations to develop better treatment against antibiotic resistant S.maltophilia strains. Note de contenu : Table of contents PRESENTATION OF THE INTERNSHIP PLACE ............................................................................................. 5 INTRODUCTION........................................................................................................................................ 7 1. GENERAL CONTEXT .......................................................................................................................... 8 1.1. Definitions ......................................................................................................................... 8 1.2. History ............................................................................................................................... 8 1.3. Structure and classification .............................................................................................. 11 1.4. Reproduction ................................................................................................................... 12 1.5. Ecology ............................................................................................................................ 13 1.6. Antibiotics and bacterial resistance ................................................................................. 14 1.7. Phage therapy ................................................................................................................. 15 1.8. Phage therapy vs Antibiotic therapy ................................................................................ 15 2. OBJECTIVE AND STRATEGY ............................................................................................................... 18 2.1. Objective ......................................................................................................................... 18 2.2. Strategy........................................................................................................................... 18 3. MATERIALS AND METHODS .............................................................................................................. 19 3.1. Materials and reagents ................................................................................................... 19 3.2. Methods .......................................................................................................................... 20 3.2.1. Isolation of phages by culture enrichment method and plaque purification ................................ 20 3.2.2. DAO titration method ....................................................................................................................... 21 3.2.3. Propagation of phages by DAO ........................................................................................................ 22 3.2.4. Determination of phage activity by spot test .................................................................................. 23 3.2.5. Screening of phages against collection of clinical strains ............................................................... 24 3.2.6. Omnilog experiment ......................................................................................................................... 24 4. RESULTS AND DISCUSSION ............................................................................................................... 28 4.1. Isolation of phages from two water samples ................................................................... 28 4.2. Purification of newly isolated phages .............................................................................. 30 4.3. Propagation of the 11 newly isolated phages .................................................................. 32 4.4. Determination of phage activity by spot test on host strains ............................................ 33 4.5. Screening of the new phages against collection of clinical strains .................................... 37 4.6. Omnilog experiments ...................................................................................................... 40 CONCLUSION.......................................................................................................................................... 47 5. BIBLIOGRAPHY .............................................................................................................................. 49 6. APPENDICES ................................................................................................................................. 52 Permalink : ./index.php?lvl=notice_display&id=119413 Isolation and characterization of Stenotrophomonas maltophilia phages active against clinical strains [TFE / Mémoire] / Maxine Monoyer ; Nicolas Kesteman, Directeur de la recherche . - Montignies-sur-Sambre : Helha. Paramédical - Biologie médicale, 2024. Le fichier numérique de ce document est disponible uniquement pour les membres de la Haute Ecole Louvain-en-Hainaut ainsi que ses étudiants. Veuillez-vous connecter pour accéder à votre compte lecteur Langues : Anglais (eng) Index. décimale : TFE Bio Med TFE Biologie médicale Résumé : This study investigates the isolation and characterization of phages active against clinical strains of Stenotrophomonas maltophilia. This opportunistic bacteria present significant treatment challenges due to its resistance to antibiotics. The research objective was to identify new phages with a lytic activity on several clinical strains of S.maltophilia to use in combination with antibiotic treatment. Phages were isolated from two different sewage water samples then purified after five rounds to be propagate after and titrated to know the concentration of phages. Out of the initial samples, 9 phages were successfully isolated and demonstrated distinct plaque morphology. Their efficacity was evaluated against clinical strains and showed that several phages exhibited significant lytic activity against those strains. Additionally, the study explored the activity of phages on bacteria using an automated system called Omnilog that measures the cell respiration. Those tests showed that some phages delay the bacterial growth of a few hours. Further tests were made, using a combination of phage on a strain bit it did not enhance activity of the phages on the strain. The activity of a phage was also tested in combination with an antibiotic, Ciprofloxacin, and resulted in complete inhibition of bacterial growth whilst the antibiotic alone only delayed growth. Another test was made using another phage in combination with Ciprofloxacin on another strain and did not show a better activity on the strain of the phage in combination with antibiotic than the antibiotic alone. This dual approach, using phage and antibiotics, could be a more effective strategy to treat resistant bacterial infections. This study underscores the importance of further explorations of phage and antibiotics combinations to develop better treatment against antibiotic resistant S.maltophilia strains. Note de contenu : Table of contents PRESENTATION OF THE INTERNSHIP PLACE ............................................................................................. 5 INTRODUCTION........................................................................................................................................ 7 1. GENERAL CONTEXT .......................................................................................................................... 8 1.1. Definitions ......................................................................................................................... 8 1.2. History ............................................................................................................................... 8 1.3. Structure and classification .............................................................................................. 11 1.4. Reproduction ................................................................................................................... 12 1.5. Ecology ............................................................................................................................ 13 1.6. Antibiotics and bacterial resistance ................................................................................. 14 1.7. Phage therapy ................................................................................................................. 15 1.8. Phage therapy vs Antibiotic therapy ................................................................................ 15 2. OBJECTIVE AND STRATEGY ............................................................................................................... 18 2.1. Objective ......................................................................................................................... 18 2.2. Strategy........................................................................................................................... 18 3. MATERIALS AND METHODS .............................................................................................................. 19 3.1. Materials and reagents ................................................................................................... 19 3.2. Methods .......................................................................................................................... 20 3.2.1. Isolation of phages by culture enrichment method and plaque purification ................................ 20 3.2.2. DAO titration method ....................................................................................................................... 21 3.2.3. Propagation of phages by DAO ........................................................................................................ 22 3.2.4. Determination of phage activity by spot test .................................................................................. 23 3.2.5. Screening of phages against collection of clinical strains ............................................................... 24 3.2.6. Omnilog experiment ......................................................................................................................... 24 4. RESULTS AND DISCUSSION ............................................................................................................... 28 4.1. Isolation of phages from two water samples ................................................................... 28 4.2. Purification of newly isolated phages .............................................................................. 30 4.3. Propagation of the 11 newly isolated phages .................................................................. 32 4.4. Determination of phage activity by spot test on host strains ............................................ 33 4.5. Screening of the new phages against collection of clinical strains .................................... 37 4.6. Omnilog experiments ...................................................................................................... 40 CONCLUSION.......................................................................................................................................... 47 5. BIBLIOGRAPHY .............................................................................................................................. 49 6. APPENDICES ................................................................................................................................. 52 Permalink : ./index.php?lvl=notice_display&id=119413

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