Dear colleagues—urologists, gynaecologists, general practitioners, and all healthcare professionals involved in the management of urinary tract infections (UTIs) - The management and prevention of urinary tract infections (UTIs) constitute a routine component of clinical practice for many healthcare providers. This Newsletter aims to review the most recent recommendations concerning the management and prevention of urinary tract infections. Our principal objectives are to reduce the incidence of infection, to avoid inappropriate antibiotic prescribing in order to limit the development of antimicrobial resistance, and to evaluate the available evidence regarding non-antibiotic preventive strategies. Robust scientific evidence and current guideline recommendations underpin the information presented herein.

This newsletter include two that examines the impact of urinary pH on the antimicrobial susceptibility of different antibiotics. Another article evaluated the utility of a portable digital pH-meter reporting higher cost-effectiveness for urinary pH monitoring in comparison with dipsticks on patients with urinary lithiasis.

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Fosfomycin is recommended as a first-line treatment for localised urinary tract infections (UTIs). In some cases, it may also be used to treat infections caused by multidrug-resistant (MDR) Gram-negative bacilli. Approximately 95% of absorbed fosfomycin is excreted by the kidneys, resulting in high urinary concentrations. Therefore, fosfomycin is particularly useful in the management of UTIs, and changes in urinary pH may affect its antimicrobial activity.

This research aimed to investigate whether urinary acidification could improve bacterial susceptibility to orally administered fosfomycin. The study assessed the minimum inhibitory concentrations (MICs) of fosfomycin at pH 6.0 and pH 7.0 in 245 Gram-negative bacterial isolates, including 158 Escherichia coli isolates and 87 Klebsiella spp. isolates, collected from patients with UTIs. The initial evaluation showed that fosfomycin was highly effective against E. coli (MIC₉₀ ≤16 μg/mL), but showed limited activity against Klebsiella spp. (MIC₉₀ >512 μg/mL). However, following urinary acidification, susceptibility increased by 71%, and a reduction in bacterial survival was also observed. Several strains that were resistant to fosfomycin at pH 7.0 became susceptible at pH 6.0. The greatest effect was observed among Klebsiella spp., for which the cumulative fraction of response (CFR) increased from 28% to 55% when the urinary pH was reduced from 7.0 to 6.0. Therefore, a single oral dose of 3 g of fosfomycin was effective against E. coli isolates with an MIC of ≤64 mg/L and was able to achieve a probability of target attainment of ≥90%.

The authors suggested that the enhanced activity of fosfomycin in an acidic environment may be explained by its physicochemical properties. The molecular structure of fosfomycin contains an epoxide ring linked to a phosphate group, the degree of ionisation of which depends on pH. At an acidic pH, fosfomycin is in a less ionised and more lipophilic state, allowing a greater proportion of the available antibiotic molecules to enter bacterial cells. This may result in increased antimicrobial activity in acidic urine.

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Human urinary pH can range from acidic (approximately pH 4.5) to alkaline (approximately pH 8.0). The efficacy of antibiotics commonly used in the management of urinary tract infections (UTIs) has been shown to be influenced by urinary pH. Fluoroquinolones, co-trimoxazole, aminoglycosides and macrolides generally demonstrate greater activity under alkaline conditions, whereas tetracyclines, nitrofurantoin and fosfomycin show increased activity at an acidic pH. However, the effect of urinary pH on the activity of many β-lactam antibiotics remains unclear.

The present study specifically evaluated the impact of urinary pH on the antimicrobial activity of ceftolozane/tazobactam and meropenem against clinical isolates of Escherichia coli, Klebsiella pneumoniae and Proteus mirabilis. Minimum inhibitory concentrations (MICs) were determined for 30 clinical isolates of E. coli, 25 K. pneumoniae isolates and 25 P. mirabilis isolates using standard growth media at pH 5.0 and pH 7.0. The growth of E. coli was not affected by pH. In contrast, bacterial growth of K. pneumoniae and P. mirabilis was greater at pH 7.0 than at lower pH values. However, an acidic urinary pH appeared to have a negative impact on the antimicrobial activity of both ceftolozane/tazobactam and meropenem.

These findings suggest that urinary pH may be relevant to the management of UTIs, as it could influence the antibiotic dose required to achieve adequate antimicrobial activity. Antibiotics such as fluoroquinolones may demonstrate greater activity in alkaline urine, whereas agents such as fosfomycin appear to be more effective in acidic urine. Importantly, not all members of the Enterobacterales show the same susceptibility at different pH levels. For example, higher antibiotic exposure may be required for infections caused by Klebsiella spp. compared with those caused by E. coli.

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This research focused on the utility of a portable digital pH meter for assessing urinary pH. Urinary pH plays an important role in patients with urolithiasis and in the management of urinary tract infections (UTIs), as it can influence both microbial growth and antibiotic efficacy. The study consisted of a systematic review including 13 studies involving a total of 2,801 participants. The Lit-Control^® pH Meter is a portable digital device that offers a potentially more accurate, reproducible and reliable alternative for point-of-care urinary pH measurement. The device provides high-resolution digital readings, minimises inter-observer variability and allows data logging, which may facilitate remote monitoring.

The objective of the systematic review was to evaluate the cost-effectiveness of this device compared with traditional urine dipsticks, that are prone to subjective interpretation because of several factors, including ambient lighting conditions, hydration status, urine concentration and urine colour.

The Lit-Control^® pH Meter 2.0 is the most cost-effective long-term option for preventing recurrence, demonstrating superior urinary pH accuracy versus reagent strips (97% vs. 54%) and five times higher resolution (0.1 vs. 0.5 pH units). 95% of measurements fall within the target therapeutic range, supporting more precise clinical decisions. With a cost of €590 per avoided episode, compared with €1,169–2,337 for strips, it can generate savings of over €4,500 per avoided episode. Combined with the myLit-Control^® App, it may further improve adherence and help reduce recurrence.

The Lit-Control^® pH Meter 2.0 provides added clinical and economic value versus reagent strips, with greater accuracy and standardization supporting its use in routine practice and potential consideration in future clinical guideline recommendations, ultimately contributing to more individualized patient management and a reduced burden of recurrent urolithiasis.