Human serum lipids affect Staphylococcus aureus sensitivity to phage infection Claudia Campobasso, Elisa Fausti, Daria Bottai, Barbara Turchi, Novella Cesta, et al. International Journal of Antimicrobial Agents, 2025 OBJECTIVES: To explore phage therapy as an alternative for targeting multidrug-resistant bacterial strains, it is crucial to study phage-bacteria interaction under conditions that mimic in vivo environments. Recent studies have demonstrated that staphylococcal phage activity can be significantly hindered by human blood components, including plasma and serum. This study aimed to identify serum components responsible for phage inhibition and assess whether this effect occurred across multiple Staphylococcus aureus strains. METHODS: Phage Sb-1 activity against S. aureus ATCC 43300 was tested by pre-incubating or co-incubating bacteria and phages with 30% (v/v) heat-inactivated (56 °C and 80 °C) human, bovine, or foetal calf serum, IgG-depleted or delipidated serum, and BSA. Bacteria were incubated with serum before phage exposure, followed by washing with 0.1% Triton X-100. Additionally, growth kinetics of ten S. aureus strains incubated with or without Sb-1 were assessed over 24 hours in the presence of human serum. RESULTS: We found that adult human serum completely impairs phage infectivity due to interactions between serum components and bacterial cells rather than direct phage neutralisation. Albumin, IgG, and thermolabile components were demonstrated not to significantly contribute to the inhibitory effect, whereas lipids were identified as playing a key role. Furthermore, the sensitivity of different bacterial strains to phages was shown to be differentially affected by the presence of serum, as two of the strains tested remained susceptible to lysis despite serum exposure. CONCLUSIONS: Taken together, our findings suggest that serum lipid fraction impacts phage infectivity in a strain-specific manner, highlighting the need for tailored approaches for phage therapy.
Bacteriophage-enhanced doxycycline activity against Escherichia coli in chronic bacterial prostatitis Novella Cesta, Alessandro Fusco, Caterina Ferretti, Alessandro Materazzi, Anna Altieri, et al. International Journal of Antimicrobial Agents, 2025 Objectives Prostatitis caused by antibiotic-resistant Escherichia coli pose a significant treatment challenge. Phage therapy is emerging as a promising antibacterial strategy. We report the case of a patient with a prostatitis caused by an ESBL-producing E. coli successfully treated with with oral doxycycline and two phage cocktails. The use of doxycycline was supported by the detection of Mycoplasma spp. in the patient’s urine. We also tested the same phage-antibiotic combination against a panel of different E. coli strains in vitro . Methods A patient received oral SES and PYO phage cocktails alongside oral doxycycline for 30 days. The MIC values of doxycycline and phages alone and in combination were evaluated by checkboard assay versus five E. coli isolates, including the patient’s strain. Synergy was assessed using a modified fractional inhibitory concentration (FIC) index. Data were analysed by synogram and interaction plot based on the percentage reduction of the absorbance values (OD570) between untreated control and treated samples. Growth curves were performed over 24 hours to monitor bacterial replication in presence/absence of phage and/or antibiotic. Results After treatment, microbiological cultures were negative, and symptoms remitted. In vitro , synergy/additive effect between doxycycline and phages was observed in three out of five E. coli isolates. Synogram analysis showed the synergistic effect versus one strain, while an additive effect was observed for the other four isolates. Growth curve analysis demonstrated enhanced bacterial growth inhibition for up to 12 hours with the combined treatment compared to either therapy alone. Conclusions Although the E. coli strain was resistant to doxycycline, the antibiotic was administered specifically to target the Mycoplasma infection. Interestingly, the enhanced in vitro activity observed when the antibiotic was combined with phages versus E. coli suggests that this combination may be effective in eradicating chronic prostatitis caused by ESBL-producing E. coli .
Characterisation of four novel bacteriophages targeting carbapenem-resistant Klebsiella pneumoniae and their lytic activity alone and in combination Elisa Fausti, Andrea Bonacorsi, Novella Cesta, Cesira Giordano, Simona Barnini, Magda Marchetti, Claudia Campobasso, Rob Lavigne, Anna Altieri, Cartesio D’Agostini, Marco Iannetta, Vincenzo Malagnino, Arianna Tavanti, Loredana Sarmati, Mariagrazia Di Luca Current Research in Microbial Sciences, 2025 • Four newly isolated lytic phages showed no antibiotic resistance or virulence genes • Phages demonstrated rapid adsorption, short latent period and variable burst size • Phages were active against carbapenemase-producing Klebsiella pneumoniae strains • Phage cocktail enhanced lytic activity compared to individual phages • The antibiofilm activity suggests potential use in biofilm-related infection Klebsiella pneumoniae is a nosocomial pathogen with rising levels of antibiotic resistance, increasing interest in bacteriophage therapy as an adjunct or alternative treatment. This study aimed to isolate and characterise bacteriophages active against multidrug-resistant K. pneumoniae and evaluate their efficacy. Four lytic phages, Kilian, Trimon, Jurek, and Olmo were isolated from water sources using K. pneumoniae ATCC BAA-2146 as host. Genome analysis revealed no known lysogeny, antibiotic resistance, or virulence-associated genes, supporting their suitability for therapeutic use. Electron microscopy classified Kilian, Trimon, and Jurek as siphoviruses, and Olmo as a myovirus. All phages showed rapid adsorption (2.5–5 min), short latent periods (5–15 min), and variable burst sizes (22–474 PFU/cell). The phages exhibited a narrow host range, collectively infecting 13 out of 90 tested K. pneumoniae clinical isolates, including carbapenemase producers and high-risk clones (ST11, ST512, ST147, ST307, ST37). The phages were then formulated into a cocktail and tested in vitro , showing enhanced and sustained bacterial growth suppression compared to single phages, with strain- and multiplicity of infection-dependent effects. Antibiofilm activity was assessed on preformed biofilms grown on porous glass beads. Three hours after treatment, both individual phages and the cocktail reduced viable biofilm-associated cells more than 4-log 10 compared to untreated controls. Finally, high titers of purified phages obtained by cesium chloride gradient ultracentrifugation showed no adverse effects on Galleria mellonella viability, indicating a safe profile. These findings support the potential of phage combinations to target multidrug-resistant and biofilm-associated K. pneumoniae infections.
Evaluation of antibiofilm activity of cefiderocol alone and in combination with imipenem against Pseudomonas aeruginosa Caterina Ferretti, Noemi Violeta Poma, Mariano Bernardo, Laura Rindi, Novella Cesta, Arianna Tavanti, Carlo Tascini, Mariagrazia Di Luca Journal of Global Antimicrobial Resistance, 2024 OBJECTIVES: The main aim of this study was to evaluate the antibiofilm activity of cefiderocol alone and in combination with imipenem vs. sessile cells of Pseudomonas aeruginosa, assessing a potential synergistic bactericidal effect. METHODS: Ten P. aeruginosa clinical isolates from infected implants and bloodstream were included in the study. Cefiderocol was tested alone and in combination with imipenem on 24-h-old P. aeruginosa biofilm formed on porous glass beads. For each antibiotic formulation, minimum bactericidal biofilm concentration (MBBC), defined as the lowest concentration that determined a reduction of at least 3 log10 CFU/mL compared with the untreated control, was evaluated. Scanning electron microscopy (SEM) was used to investigate the biofilm of P. aeruginosa treated with cefiderocol, imipenem, or their combination. RESULTS: Cefiderocol and imipenem were tested alone on P. aeruginosa biofilm and a reasonable reduction in the number of viable cells was observed, especially at high drug concentrations tested. The synergistic effect of cefiderocol in combination with imipenem was evaluated for five selected isolates. Cotreatment with the two drugs led to a remarkable reduction of cell viability by resulting in synergistic bactericidal activity in all tested strains and in synergistic eradicating activity in only one isolate. SEM analysis revealed that, in cefiderocol-treated biofilm, bacterial cells became more elongated than in the untreated control, forming filaments in which bacterial division seems to be inhibited. CONCLUSIONS: Cefiderocol exhibited an encouraging antibiofilm activity against tested strains, representing a valid option for the treatment of P. aeruginosa biofilm-associated infections, especially when administered in combination with imipenem.
Personalized bacteriophage therapy outcomes for 100 consecutive cases: a multicentre, multinational, retrospective observational study Jean-Paul Pirnay, Sarah Djebara, Griet Steurs, Johann Griselain, Christel Cochez, Steven De Soir, Tea Glonti, An Spiessens, Emily Vanden Berghe, Sabrina Green, Jeroen Wagemans, Cédric Lood, Eddie Schrevens, Nina Chanishvili, Mzia Kutateladze, Mathieu de Jode, Pieter-Jan Ceyssens, Jean-Pierre Draye, Gilbert Verbeken, Daniel De Vos, Thomas Rose, Jolien Onsea, Brieuc Van Nieuwenhuyse, Kim Win Pang, Willem-Jan Metsemakers, Dimitri Van der Linden, Olga Chatzis, Anaïs Eskenazi, Angel Lopez, Adrien De Voeght, Anne Françoise Rousseau, Anne Tilmanne, Daphne Vens, Jean Gérain, Brice Layeux, Erika Vlieghe, Ingrid Baar, Sabrina Van Ierssel, Johan Van Laethem, Julien Guiot, Sophie De Roock, Serge Jennes, Saartje Uyttebroek, Laura Van Gerven, Peter W. Hellings, Lieven Dupont, Yves Debaveye, David Devolder, Isabel Spriet, Paul De Munter, Melissa Depypere, Michiel Vanfleteren, Olivier Cornu, Stijn Verhulst, Tine Boiy, Stoffel Lamote, Thibaut Van Zele, Grégoire Wieërs, Cécile Courtin, David Lebeaux, Jacques Sartre, Tristan Ferry, Frédéric Laurent, Kevin Paul, Mariagrazia Di Luca, Stefan Gottschlich, Tamta Tkhilaishvili, Novella Cesta, Karlis Racenis, Telma Barbosa, Luis Eduardo López-Cortés, Maria Tomás, Martin Hübner, Truong-Thanh Pham, Paul Nagtegaal, Jaap Ten Oever, Johannes Daniels, Maartje Loubert, Ghariani Iheb, Joshua Jones, Lesley Hall, Matthew Young, Nana Balarjishvili, Marina Tediashvili, Yigang Tong, Christine Rohde, Johannes Wittmann, Ronen Hazan, Ran Nir-Paz, Joana Azeredo, Victor Krylov, David Cameron, Melissa Pitton, Yok-Ai Que, Gregory Resch, Shawna McCallin, Matthew Dunne, Samuel Kilcher, Patrick Soentjens, Rob Lavigne, Maya Merabishvili, , and Nature Microbiology, 2024 In contrast to the many reports of successful real-world cases of personalized bacteriophage therapy (BT), randomized controlled trials of non-personalized bacteriophage products have not produced the expected results. Here we present the outcomes of a retrospective observational analysis of the first 100 consecutive cases of personalized BT of difficult-to-treat infections facilitated by a Belgian consortium in 35 hospitals, 29 cities and 12 countries during the period from 1 January 2008 to 30 April 2022. We assessed how often personalized BT produced a positive clinical outcome (general efficacy) and performed a regression analysis to identify functional relationships. The most common indications were lower respiratory tract, skin and soft tissue, and bone infections, and involved combinations of 26 bacteriophages and 6 defined bacteriophage cocktails, individually selected and sometimes pre-adapted to target the causative bacterial pathogens. Clinical improvement and eradication of the targeted bacteria were reported for 77.2% and 61.3% of infections, respectively. In our dataset of 100 cases, eradication was 70% less probable when no concomitant antibiotics were used (odds ratio = 0.3; 95% confidence interval = 0.127–0.749). In vivo selection of bacteriophage resistance and in vitro bacteriophage–antibiotic synergy were documented in 43.8% (7/16 patients) and 90% (9/10) of evaluated patients, respectively. We observed a combination of antibiotic re-sensitization and reduced virulence in bacteriophage-resistant bacterial isolates that emerged during BT. Bacteriophage immune neutralization was observed in 38.5% (5/13) of screened patients. Fifteen adverse events were reported, including seven non-serious adverse drug reactions suspected to be linked to BT. While our analysis is limited by the uncontrolled nature of these data, it indicates that BT can be effective in combination with antibiotics and can inform the design of future controlled clinical trials. BT100 study, ClinicalTrials.gov registration: NCT05498363.
Management of an elderly patient with retention of a steel nail in the scrotum: A case report Iacopo Meneghetti, Novella Cesta, Luca Mosillo, Simone Belli, Daniele Bianchi, Maurizio De Maria Archivio Italiano Di Urologia E Andrologia, 2024 Background: The retention of foreign bodies inside the body during ludic/sexual procedures or for traumatism represents one of the causes of visits to accident and emergency departments that often requires surgical removal of the foreign body. However, there are cases where the discovery of such foreign bodies takes place after many years, as in patients that are slightly compromised from a neuro-sociological point of view. Case presentation: A 76-year-old male presented to an outpatient urological examination due to an increase in scrotal volume. At the ultrasound check, an acoustic interference from a solid object was detected, for which computed tomography was requested. The computed tomography scan revealed the presence of an elongated metal body in the perineum. The removal of the foreign body in the operating theatre was then scheduled. A 10 cm long stainless-steel nail located within an abscessed foreign body granuloma was identified and removed via a scrotal access. Four days later, a new surgical toilet was performed due to minimal necrosis of the skin flaps. The patient then performed three more dressings in the operating theatre during the following week. Healing took place by secondary intention until a perfect healing of the surgical wound was obtained. Conclusions: Removal of foreign bodies from the perineum in case of infection can be challenging. Careful attention and postoperative dressings are crucial for the success of the case.
Efficacy of Convalescent Plasma to Treat Long-Standing COVID-19 in Patients with B-Cell Depletion Luca Tomisti, Francesca Angelotti, Mirco Lenzi, Francesco Amadori, Giovanni Sarteschi, Anna Porcu, Anna-Lisa Capria, Gloria Bertacca, Stefania Lombardi, Guido Bianchini, Antonella Vincenti, Novella Cesta Life, 2023 The use of antivirals, corticosteroids, and IL-6 inhibitors has been recommended by the WHO to treat COVID-19. CP has also been considered for severe and critical cases. Clinical trials on CP have shown contradictory results, but an increasing number of patients, including immunocompromised ones, have shown benefits from this treatment. We reported two clinical cases of patients with prolonged COVID-19 infection and B-cell depletion who showed rapid clinical and virological recovery after the administration of CP. The first patient in this study was a 73-year-old female with a history of follicular non-Hodgkin lymphoma previously treated with bendamustine followed by maintenance therapy with rituximab. The second patient was a 68-year-old male with chronic obstructive pulmonary disease, bipolar disorder, alcoholic liver disease, and a history of mantellar non-Hodgkin lymphoma treated with rituximab and radiotherapy. After the administration of CP, both patients showed a resolution of symptoms, improvement of their clinical conditions, and a negative result of the nasopharyngeal swab test. The administration of CP might be effective in resolving symptoms and improving clinical and virological outcomes in patients with B-cell depletion and prolonged SARS-CoV2 infections.
Application of Phage Therapy in a Case of a Chronic Hip-Prosthetic Joint Infection due to Pseudomonas aeruginosa: An Italian Real-Life Experience and in Vitro Analysis Novella Cesta, Marco Pini, Tiziana Mulas, Alessandro Materazzi, Ernesto Ippolito, Jeroen Wagemans, Mzia Kutateladze, Carla Fontana, Loredana Sarmati, Arianna Tavanti, Rob Lavigne, Massimo Andreoni, Mariagrazia Di Luca Open Forum Infectious Diseases, 2023 BackgroundProsthetic joint infection (PJI) caused by Pseudomonas aeruginosa represents a severe complication in orthopedic surgery. We report the case of a patient with chronic PJI from P. aeruginosa successfully treated with personalized phage therapy (PT) in combination with meropenem.MethodsA 62-year-old woman was affected by a chronic right hip prosthesis infection caused by P. aeruginosa since 2016 . The patient was treated with phage Pa53 (I day 10 mL q8h, then 5 mL q8h via joint drainage for 2 weeks) in association with meropenem (2gr q12h iv) after a surgical procedure. A 2-year clinical follow up was performed. An in vitro bactericidal assay of the phage alone and in combination with meropenem against a 24-hour-old biofilm of bacterial isolate was also carried out.ResultsNo severe adverse events were observed during PT. Two years after suspension, there were no clinical signs of infection relapse, and a marked leukocyte scan showed no pathological uptake areas. In vitro studies showed that the minimum biofilm eradicating concentration of meropenem was 8 µg/mL. No biofilm eradication was observed at 24 hours incubation with phages alone (108 plaque-forming units [PFU]/mL). However, the addition of meropenem at suberadicating concentration (1 µg/mL) to phages at lower titer (103 PFU/mL) resulted in a synergistic eradication after 24 hours of incubation.ConclusionsPersonalized PT, in combination with meropenem, was found to be safe and effective in eradicating P. aeruginosa infection. These data encourage the development of personalized clinical studies aimed at evaluating the efficacy of PT as an adjunct to antibiotic therapy for chronic persistent infections.
Phage-Based Control of Methicillin Resistant Staphylococcus aureus in a Galleria mellonella Model of Implant-Associated Infection Alessandro Materazzi, Daria Bottai, Claudia Campobasso, Ann-Brit Klatt, Novella Cesta, Margherita De Masi, Andrej Trampuz, Arianna Tavanti, Mariagrazia Di Luca International Journal of Molecular Sciences, 2022 Staphylococcus aureus implant-associated infections are difficult to treat because of the ability of bacteria to form biofilm on medical devices. Here, the efficacy of Sb-1 to control or prevent S. aureus colonization on medical foreign bodies was investigated in a Galleria mellonella larval infection model. For colonization control assays, sterile K-wires were implanted into larva prolegs. After 2 days, larvae were infected with methicillin-resistant S. aureus ATCC 43300 and incubated at 37 °C for a further 2 days, when treatments with either daptomycin (4 mg/kg), Sb-1 (107 PFUs) or a combination of them (3 x/day) were started. For biofilm prevention assays, larvae were pre-treated with either vancomycin (10 mg/kg) or Sb-1 (107 PFUs) before the S. aureus infection. In both experimental settings, K-wires were explanted for colony counting two days after treatment. In comparison to the untreated control, more than a 4 log10 CFU and 1 log10 CFU reduction was observed on K-wires recovered from larvae treated with the Sb-1/daptomycin combination and with their singular administration, respectively. Moreover, pre-infection treatment with Sb-1 was found to prevent K-wire colonization, similarly to vancomycin. Taken together, the obtained results demonstrated the strong potential of the Sb-1 antibiotic combinatory administration or the Sb-1 pretreatment to control or prevent S. aureus-associated implant infections.
