Complicated urinary tract infections (cUTIs) pose a significant health burden in the United States, characterized by their association with structural or functional abnormalities of the urinary tract, comorbid conditions, or the presence of indwelling urinary devices. cUTIs are more challenging to treat than uncomplicated UTIs, often leading to more severe outcomes. The increasing rates of antimicrobial resistance complicate the treatment landscape, with pathogens such as Klebsiella pneumoniae and Escherichia coli playing major roles.

cUTIs account for a substantial proportion of urinary tract infections, with an estimated 3-4 million cases annually in the US. These infections are particularly prevalent among patients with indwelling catheters, urological abnormalities, immunocompromised states, or underlying chronic diseases such as diabetes.

Patients with cUTIs experience significant morbidity, including prolonged symptoms, frequent recurrences, and the potential for severe complications such as pyelonephritis, renal abscesses, and urosepsis. These infections often necessitate longer hospital stays, multiple diagnostic tests, and more intensive treatments, leading to substantial patient discomfort and a reduced quality of life.

The mortality rate associated with cUTIs is notable, particularly in vulnerable populations such as the elderly, immunocompromised individuals, and those with chronic comorbidities. Urosepsis, a severe and life-threatening complication of cUTIs, has a high mortality rate, estimated at 20-40%. The presence of multidrug-resistant organisms further increases the risk of fatal outcomes.

The economic impact of cUTIs on the US healthcare system is significant. The cost of managing cUTIs is considerably higher than that of uncomplicated UTIs, ranging from $3,000 to $7,000 per episode. The annual financial burden of cUTIs is estimated to exceed $2 billion, driven by extended hospitalizations, intensive care admissions, and the need for complex and prolonged antimicrobial therapy.

The management of cUTIs involves substantial resource utilization, including advanced diagnostic procedures (e.g., imaging studies), long-term antibiotic treatments, and often surgical interventions to address underlying anatomical abnormalities. The need for multidisciplinary care, involving urologists, infectious disease specialists, and nephrologists, further adds to the healthcare resource demands.

The rising rates of antimicrobial resistance are a major concern in the treatment of cUTIs. Multidrug-resistant organisms, including extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae, carbapenem-resistant Enterobacteriaceae (CRE), and vancomycin-resistant Enterococci (VRE), are increasingly implicated in these infections. The presence of resistant pathogens limits the effectiveness of standard treatments and necessitates the use of more expensive and potentially more toxic antibiotics.

Klebsiella pneumoniae is a significant pathogen in cUTIs, particularly noted for its ability to produce ESBLs and carbapenemases, which confer resistance to a broad range of antibiotics. Infections caused by K. pneumoniae are associated with severe clinical outcomes, increased length of hospital stays, and higher healthcare costs. The emergence of carbapenem-resistant K. pneumoniae (CRKP) poses a critical challenge, as treatment options become severely limited, leading to higher morbidity and mortality rates.

Escherichia coli remains the most common pathogen in both uncomplicated and complicated UTIs. However, strains causing cUTIs often exhibit resistance to multiple antibiotics, including fluoroquinolones, beta-lactams, and aminoglycosides. The prevalence of ESBL-producing E. coli complicates the treatment landscape, as these strains are resistant to many first-line therapies. Infections caused by multidrug-resistant E. coli are associated with worse clinical outcomes, prolonged hospital stays, and increased healthcare costs.

Complicated urinary tract infections (cUTIs) impose a significant burden on the US healthcare system, characterized by high morbidity and mortality rates and substantial economic costs. The increasing prevalence of antimicrobial resistance, particularly involving pathogens such as Klebsiella pneumoniae and Escherichia coli, exacerbates the challenges in managing these infections. Addressing the burden of cUTIs requires a multifaceted approach, including robust infection control practices, antimicrobial stewardship programs, and the development of new diagnostic tools and therapeutic strategies to effectively combat resistant pathogens like LBP-EC01 and LBP-KP01.

LBP-KP01 is a cocktail of engineered bacteriophages designed to precisely remove K. pneumoniae in patients with cUTIs. The rise of antibiotic resistance has led to a revival in the investigative and rescue use of bacteriophage (phage) therapy in patients with difficult-to-treat or life-threatening infections where there are frequently no alternative therapies. Locus has deployed a technology stack that provides a scale and capability set that has never been used in phage therapy, which is redefining the way engineered bacteriophages are used to treat disease.