Uruguay Reports Latin America’s First Phage Therapy for a Resistant Hip Prosthesis Infection
Uruguay has reported an important advance in the clinical development of bacteriophage therapy in Latin America. The biotechnology company Kinzbio and the Banco de Prótesis, a specialist centre for osteoarticular surgery, used a personalised phage treatment in a 30-year-old patient with a difficult infection associated with a hip prosthesis. According to information published by the Uruguayan newspaper La Diaria, the infection was caused by Stenotrophomonas maltophilia, an uncommon organism in prosthetic joint infections that is naturally resistant to several antimicrobial classes. Conventional diagnostic methods initially failed to identify the bacterium, requiring the medical and biotechnology teams to use metagenomic sequencing before a targeted treatment could be developed. The patient reportedly recovered without adverse effects, and the infection was described as having been eradicated.
Kinzbio presents the intervention as the first reported application of its kind within a Latin American reference centre for joint disorders. The case is particularly notable because the company says the phage treatment was introduced early against a microorganism considered difficult to treat with conventional antibiotics, rather than being reserved exclusively as an experimental rescue after every other option had failed. The result has not yet been described in a peer-reviewed clinical publication, so the available evidence remains based on institutional and media reports. Nevertheless, the case illustrates several of the central challenges that will determine whether personalised phage therapy can move from exceptional access into routine infectious disease care.
Hip and knee replacements restore mobility and quality of life for many patients, but infection remains one of their most serious complications. Once bacteria reach the surface of an implant, they can attach to the material and organise into a biofilm. A biofilm is not simply a collection of free-living bacterial cells. It is a structured microbial community embedded in a matrix containing polysaccharides, proteins, extracellular nucleic acids and host-derived material. This environment can restrict antimicrobial penetration and generate regions with different oxygen, nutrient and metabolic conditions.
Bacteria growing slowly inside a mature biofilm may be less vulnerable to antibiotics that act most efficiently against actively dividing cells. Other subpopulations can enter transient tolerant states, while the implant surface lacks the same vascular access and immune surveillance found in healthy tissue. Treatment may consequently require prolonged antibiotic administration, surgical debridement, removal of infected tissue and, in severe cases, replacement of the prosthesis itself. Recurrence can occur if a residual bacterial population survives on the implant or in the surrounding tissues.
The biological characteristics of Stenotrophomonas maltophilia make such an infection particularly difficult to manage. This opportunistic Gram-negative bacterium is associated with aqueous environments and healthcare settings and possesses several intrinsic resistance mechanisms. These include multidrug efflux systems, reduced outer-membrane permeability and enzymes capable of inactivating selected antimicrobial agents. Although it is better known as a cause of respiratory, bloodstream and medical-device infections in medically vulnerable patients, its involvement in hip prosthesis infections appears to be rare. Limited clinical experience with this organism can make both diagnosis and antimicrobial selection more complicated.
One of the most scientifically important elements of the Uruguayan case was the diagnostic process. Traditional microbiological diagnosis usually depends on collecting a clinical specimen, culturing the organism and testing its susceptibility to antimicrobial agents. This remains indispensable, but it can fail when bacterial abundance is low, when a patient has already received antibiotics, when the microorganism grows slowly or when the sample contains organisms that are difficult to recover under standard laboratory conditions.
In this case, the responsible bacterium was reportedly identified only after metagenomic analysis. Instead of requiring an organism to grow in culture, metagenomic sequencing examines genetic material present in a sample and compares the resulting sequences with reference databases. This can reveal microorganisms that are missed by conventional culture, although interpretation must remain cautious. The detection of microbial DNA does not automatically demonstrate that the organism is alive or responsible for the infection. Clinical context, sample quality, background contamination and sequence abundance must all be considered.
For personalised phage therapy, molecular identification can nevertheless be decisive. A therapeutic phage cannot be selected rationally when the bacterial target remains unknown. Advanced sequencing therefore does more than improve diagnosis. It can initiate the entire therapeutic development pathway by determining which pathogen must be isolated, screened and matched against an available phage collection.
Kinzbio reported that Stenotrophomonas maltophilia was not among the species it routinely treated and that a specific therapeutic preparation had to be developed within a matter of days. This highlights the adaptability required from a personalised phage platform. Unlike a conventional broad-spectrum antibiotic, a phage usually infects only a limited range of bacteria, sometimes only a subset of strains within the same species. Rapid treatment therefore depends on access to diverse phage libraries, microbiological testing, sequencing, purification and quality-control capabilities.
A phage must first recognise and bind an accessible bacterial receptor, which may consist of a lipopolysaccharide structure, capsule component, pilus, flagellum or outer-membrane protein. Successful adsorption is only the beginning. After injecting its genome, the phage must overcome bacterial restriction systems, CRISPR-Cas immunity, abortive infection mechanisms and other intracellular defences. It must then reproduce under the physiological conditions present at the infection site and complete productive lysis.
This is why a clear zone in a rapid laboratory spot test does not automatically demonstrate therapeutic suitability. Clearing can sometimes result from very high local phage concentrations, enzymatic degradation of bacterial surface material or incomplete infection without sustained viral replication. Quantitative evaluation can include efficiency of plating, adsorption kinetics, bacterial killing curves, resistance-frequency measurements and evidence of phage amplification.
Testing under conditions relevant to biofilms is especially important for implant-associated infections. A phage that performs strongly against planktonic bacteria in liquid culture may have reduced access to cells embedded in a dense extracellular matrix. Some phages possess depolymerases or related enzymes that can degrade capsule or biofilm-associated polymers and improve penetration, but these functions vary considerably between phages and bacterial strains.
The precise composition of the phage preparation, route of administration, dosage and laboratory susceptibility results used in the Uruguayan intervention have not been disclosed in sufficient scientific detail to allow independent reproduction. The case should therefore be considered an encouraging clinical report rather than a complete therapeutic protocol.
Public reporting indicates that the clinical procedure was conducted at the Banco de Prótesis and that the surgical and biotechnology teams developed a method intended to optimise phage administration during the operation. Local delivery can be particularly attractive in prosthetic joint infections because it places the therapeutic agent directly at the site where bacteria are persisting. Systemically administered phages must circulate, survive immune clearance and reach sufficient concentrations in infected tissues. Local administration can potentially provide greater immediate exposure while limiting distribution elsewhere in the body.
The surgical environment nevertheless presents additional challenges. Phages can be affected by antiseptics, temperature, local pH, implant materials and simultaneous antibiotic exposure. The timing of administration relative to surgical debridement and irrigation may determine how long the phages remain in contact with the remaining bacterial population.
Bacterial density also influences treatment. Phages require susceptible host cells to replicate, but extremely low bacterial numbers may restrict local amplification. Conversely, a mature biofilm can contain heterogeneous and metabolically inactive populations that remain difficult to infect even when bacterial density is high. The most effective approach may therefore involve several complementary interventions. Surgery can reduce the bacterial burden and remove damaged tissue, antibiotics can target susceptible planktonic cells, and phages can provide strain-specific activity against remaining bacteria, including organisms resistant to conventional drugs.
Such combinations also complicate interpretation. When surgery, antibiotics and phages are used together, it becomes difficult to determine how much of the clinical outcome resulted from the phage preparation alone. Prospective studies, detailed case reports and transparent microbiological follow-up will be needed to define the contribution of each component.
The intervention was made possible by a national regulatory decision adopted before the case. In December 2024, Uruguay’s Ministry of Public Health issued Ordinance No. 1.162/024 authorising Kinzbio to conduct personalised bacteriophage therapy for the treatment and prevention of infections caused by multidrug-resistant bacteria. The framework requires informed consent and places responsibility for requesting the treatment with the attending physician.
This regulatory pathway is significant because uncertainty remains one of the main barriers to personalised phage treatment. Conventional medicines are generally manufactured with a stable composition and assessed through a sequence of preclinical and clinical studies before receiving marketing authorisation. Personalised phage therapy may require a different phage or cocktail for each bacterial isolate, sometimes under urgent clinical conditions. A suitable framework must protect patients while allowing biological adaptation. It must define how candidate phages are selected, sequenced, purified, characterised and released, while also establishing responsibilities for clinical monitoring, adverse-event reporting and long-term follow-up.
Uruguay’s model does not replace the need for formal clinical trials, but it provides a controlled access pathway through which selected patients can receive personalised preparations under medical supervision. Kinzbio was founded in 2021 and spent several years developing its platform before beginning treatments in 2024. The company reports having treated patients with prosthetic joint infections, respiratory infections, urinary tract infections and other serious bacterial conditions.
Kinzbio has stated that it has treated dozens of patients in Uruguay and has reported a clinical success rate exceeding 95 percent in highly complex cases. These figures come from the company and should be interpreted cautiously until complete clinical datasets are published and independently assessed. The same caution applies to claims of complete bacterial eradication. Durable success in a prosthetic infection requires long-term follow-up demonstrating that the infection does not recur and that the implant continues to function.
The absence of reported adverse effects in this patient is reassuring, but larger numbers are required to evaluate safety reliably. Phage products can contain bacterial proteins, nucleic acids, endotoxins and other contaminants if manufacturing and purification are inadequate. Endotoxin control is particularly important when phages are propagated in Gram-negative bacteria such as Stenotrophomonas maltophilia. Immune responses may also influence treatment, especially during prolonged or repeated administration. Some patients develop antibodies that neutralise phage particles, although the clinical significance depends on the administration route, treatment duration and individual immune response.
A scientifically complete report of this case would ideally describe the bacterial isolate, antimicrobial susceptibility profile, phage genome, purification process, endotoxin level, formulation, route and dose of administration, accompanying antibiotics, surgical procedure, microbiological results and duration of follow-up. Until such information becomes available, the strongest conclusion is that the intervention demonstrates feasibility. A difficult infection that conventional culture had failed to identify was diagnosed through molecular sequencing, a pathogen-specific treatment was developed, and a favourable clinical outcome was reported within an authorised national framework.
Approximately 5,000 hip and knee replacement procedures are performed each year in Uruguay, according to figures cited by Kinzbio and La Diaria. If between one and three percent become infected, around 50 to 150 patients annually could require advanced management for prosthetic joint infections. Not every one of these patients would need or qualify for phage therapy. Some infections can be successfully treated with surgery and antibiotics, while others may involve organisms for which an active phage cannot be found quickly. The potential population is nevertheless large enough to justify dedicated diagnostic and therapeutic infrastructure.
Recurrent surgery, prolonged hospitalisation, prosthesis replacement and treatment with last-line antibiotics create substantial clinical and economic costs. Combining rapid molecular diagnosis with personalised phage selection could shorten the period during which clinicians must treat without knowing the exact organism. It might also help preserve prostheses that would otherwise need to be removed. The economic value will depend on whether the costs of sequencing, phage screening, manufacturing and quality control are offset by fewer operations, shorter hospital stays and improved outcomes.
Kinzbio has stated that the cost of its personalised treatment is comparable with that of newer last-line antibiotics and that internal and external mechanisms are used to support patient access. Independent health-economic studies will be needed to evaluate this claim across different infections and healthcare systems.
The Uruguayan case also forms part of a broader regional strategy. Kinzbio has participated in an acceleration programme connected to Hospital Israelita Albert Einstein in São Paulo and is seeking regulatory approval in Brazil. The company has also reported an agreement with the pharmaceutical laboratory Scienza to facilitate access in Chile and patient evaluation in Argentina, while receiving interest from other countries, including Peru.
Regional expansion will require more than transporting phage preparations across borders. Personalised treatment depends on a connected diagnostic, manufacturing and clinical network. Patient samples must be collected correctly, pathogens must be identified, bacterial isolates must be tested against available phages, and candidate viruses must be genomically characterised and manufactured at an appropriate quality. The final preparation must then be transported under validated conditions and administered through a medically justified protocol.
Cross-border treatment also raises questions involving import authorisation, manufacturing standards, informed consent and pharmacovigilance. A preparation authorised for personalised use in Uruguay may require further assessment before being administered in another country. If these pathways can be established, Uruguay could become an important regional centre for precision antimicrobial therapies based on bacteriophages.
The significance of the Banco de Prótesis case lies in the convergence of several technologies and institutions. Metagenomic sequencing identified a pathogen that conventional culture had not detected. A personalised phage preparation was developed against an uncommon and resistant bacterium. The therapy was integrated into specialist surgical care and administered within a regulatory framework created by Uruguay’s Ministry of Public Health.
This combination is more important than any single element. Phage therapy cannot function as an isolated laboratory technique. It depends on rapid diagnostics, bacterial isolation, phage banks, genomic analysis, pharmaceutical production, clinical expertise and regulatory coordination.
The favourable outcome reported in this patient does not prove that phage therapy should become a routine first-line treatment for all prosthetic joint infections. It does, however, demonstrate that a Latin American healthcare and biotechnology ecosystem can assemble the capabilities required to deliver highly personalised antimicrobial treatment.
For a region facing the global rise of antibiotic resistance while experiencing uneven access to newly developed antimicrobial drugs, that capacity may become increasingly valuable. The case now deserves detailed scientific publication and long-term follow-up. Its lasting importance will depend not only on whether this patient remains free from infection, but also on whether the methods developed in Uruguay can be independently assessed, standardised and responsibly extended to other patients.
Source :
This article is based on reporting by Lucía Barrios for La Diaria, published on 31 July 2026:
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