Urine pH Value and Bacteriology in Purple Urine Bag Syndrome

<b><i>Background:</i></b> Purple urine bag syndrome (PUBS) is an unusual phenomenon in patients with urinary tract infections. The urine of most of these patients has an alkaline pH. <b><i>Objective:</i></b> The goal of this study was to identify infectious bacteria and determine urinary pH in patients with PUBS and to evaluate their correlation. <b><i>Methods:</i></b> PubMed was searched using the term “Purple urine bag syndrome (PUBS)” for studies on this condition published from October 1980 to September 2019. Sixty-seven patients were identified and divided into those with urine cultures positive for Gram-positive bacteria (GPB; <i>n</i> = 3), Gram-negative bacteria (GNB; <i>n</i> = 45), and mixed Gram-positive and Gram-negative bacteria (MGPNB; <i>n</i> = 19). Age, gender, urinary pH, comorbidities (diabetes and uremia), fever, shock, and mortality were compared in the 3 groups. The correlation between urinary pH and type of bacteria in urine cultures was assessed by regression analysis. <b><i>Results:</i></b> Presentation of fever in PUBS accounted for 66.7, 11.1, and 5.3%, <i>p</i> &#x3c; 0.05, in GPB, GNB, and MGPNB. Regression analyses showed that <i>Pseudomonas aeruginosa</i> was associated with less alkaline urine (regression coefficient −0.936, <i>p</i> &#x3c; 0.05), whereas <i>Proteus</i> spp. was associated with more alkaline urine (regression coefficient 0.489, <i>p</i> = 0.04). GNB were the most predominant pathogens in patients with PUBS. <b><i>Conclusion:</i></b> In PUBS, urine pH and symptom presentation are different by variable bacteria. Fever is associated with urinary GPB. <i>Proteus</i> spp. correlates with more alkaline urine, whereas <i>Pseudomonas</i> spp. correlates significantly with less alkaline urine.

Protocol concordance and impact of protocol deviations on selected outcomes in delivery of high-dose methotrexate in acute lymphoblastic leukemia in Sri Lanka.

17 Background: In Sri Lanka, children with acute lymphoblastic leukemia are treated on the UKALL 2011 protocol, which includes high-dose methotrexate (HDMTX) in high risk patients. Safe delivery of HDMTX is challenging in low resource settings, where deviation from accepted guidelines can occur frequently and result in toxicity, subsequent treatment delays, and in extreme cases, death. The goal of this study was to compare current practices to the treatment and supportive care details described in the protocol to identify the incidence and impact of guideline-discordant care to deliver HDMTX more safely children with cancer in Sri Lanka. Methods: We reviewed medical records to assess guideline concordance in 4 critical aspects of HDMTX delivery: 2 consecutive alkaline urine pH readings in the 2-hour period before starting HDMTX, 24-hour duration of MTX infusion (as opposed to early stop), the first dose of folinic acid administered later than 36 hours from start of HDMTX infusion (no inappropriately early rescue), and the administration of at least 3 folinic acid doses per course (appropriate duration of rescue). We analyzed how each deviation influenced AKI (creatinine increase of 0.3 mg/dL or more), infection, and treatment delays (defined as recovery delayed 7 days or longer from the 14 days expected between courses of HDMTX). Results: We analyzed 309 HDMTX courses in 91 patients younger than 20 years, including 105 girls (34%). In 83 courses (27%) alkaline urine was not documented prior to the start of MTX. Infusion time was less than 24 hours in 239 courses (77%), most of which finished 20-21 hours. In 37 courses (12%), the first folinic acid dose was given inappropriately early, and in 25 courses (8%) less than 3 doses of folinic acid were given. There were 2 episodes of AKI, 43 infections, 11 treatment delays and one death. None of the 4 guideline deviations were significantly associated with AKI or treatment delays. Patient sex was also not associated with any difference in guideline discordance or outcome (p>0.1 in all cases). Conclusions: Significant deviations from HDMTX administration guidelines were common, especially early completion of infusion. However, outcomes were not impacted so quality standards may require adjustment to focus only on extreme deviations likely to impact patient outcomes.

1466. Alkaline Urine: A Cause for Urinary Tract Infection Recurrence

Background Urinary tract infections (UTIs) are one of the most common indications for antibiotics in both the inpatient and outpatient setting. The purpose of this study was to examine the impact of urinary pH on recurrence of UTIs. A recent review article stated imaging should be considered for patients with a urinary pH of 7 or higher. This study examines the impact of pH on outcomes of patients with UTI to determine whether pH plays a role in recurrent infection and representations to the healthcare facility. Methods This was a retrospective chart review via the computerized patient record system. Patients over the age of 18 years who presented to the healthcare facility between January 1, 2005 to January 1, 2019 for treatment of UTIs were included in this study. Alkaline urine was defined as a urinary pH greater than or equal to 7, while acidic urine was defined as a urinary pH less than 7. Urease splitting organisms included Proteus spp., Providencia spp., and Morganella spp. Outcomes included recurrence and re-presentation to the healthcare facility within 30 days. Results A total of 793 patients were included in this study, of which 21.3% had alkaline urine. Patients with alkaline urine were more likely to have recurrence of UTI (8.3% vs. 4.3%). Patients with a catheter were more likely to have alkaline urine (30% vs 18%; P = 0.0005). As expected, alkaline urine was associated with a higher frequency of urease splitting organisms (19% in alkaline urine vs. 3% in acidic urine). Renal calculi were found in 3.6% of patients with alkaline urine; however, only 34.3% of patients with alkaline urine had imaging completed. The use of drugs which can alkalinize the urine did not differ significantly between groups. Conclusion Patients with an alkaline urinary pH were more likely to experience recurrence and readmission within 30 days. Imaging was performed in a minority of patients which may represent a potential target for stewardship programs. Alkaline urine may be a marker for urease splitting organisms and calculi formation. More widespread imaging may be able to detect stones, allowing for potential urologic intervention, preventing subsequent antibiotic courses and repeated healthcare presentations. Disclosures All authors: No reported disclosures.

Monosodium Glutamate (MSG) Renders Alkalinizing Properties and Its Urinary Metabolic Markers of MSG Consumption in Rats

Monosodium glutamate (MSG) is widely used as a flavor enhancer and its effects on human health are still debated. We aimed to investigate whether MSG can act as alkalinizing agent in murine models and if its metabolites are biomarkers of MSG consumption. For this purpose, adult male Wistar rats were given water added with 1 g% MSG or three types of control water, including sodium chloride (NaCl) and sodium bicarbonate (NaHCO3). At 14 days, urinary pH, electrolytes, urinary metabolites and ion-exchanger gene expression were determined. The results revealed that MSG-treated rats had significantly more alkaline urine and higher levels of urinary sodium and bicarbonate similar to NaHCO3 controls. These changes correlated with a lower expression of ion-exchanger genes, namely, CAII, NBC1, and AE1, which are involved in bicarbonate kidney reabsorption. The urinary metabolic profiles also revealed similar patterns for the MSG and NaHCO3 groups. In conclusion, MSG exhibits similar properties to NaHCO3, an alkalinizing agent, with regard to inducing alkaline urine, reducing bicarbonate kidney reabsorption, and generating a specific urinary metabolic pattern. We believe that these observations will be useful to further study the MSG effects in humans.

Furosemide reduces BK-αβ4-mediated K+ secretion in mice on an alkaline high-K+ diet

Special high-K diets have cardioprotective effects and are often warranted in conjunction with diuretics such as furosemide for treating hypertension. However, it is not understood how a high-K diet (HK) influences the actions of diuretics on renal K+ handling. Furosemide acidifies the urine by increasing acid secretion via the Na+-H+ exchanger 3 (NHE3) in TAL and vacuolar H+-ATPase (V-ATPase) in the distal nephron. We previously found that an alkaline urine is required for large conductance Ca2+-activated K+ (BK)-αβ4-mediated K+ secretion in mice on HK. We therefore hypothesized that furosemide could reduce BK-αβ4-mediated K+ secretion by acidifying the urine. Treating with furosemide (drinking water) for 11 days led to decreased urine pH in both wild-type (WT) and BK-β4-knockout mice (BK-β4-KO) with increased V-ATPase expression and elevated plasma aldosterone levels. However, furosemide decreased renal K+ clearance and elevated plasma [K+] in WT but not BK-β4-KO. Western blotting and immunofluorescence staining showed that furosemide treatment decreased cortical expression of BK-β4 and reduced apical localization of BK-α in connecting tubules. Addition of the carbonic anhydrase inhibitor, acetazolamide, to furosemide water restored urine pH along with renal K+ clearance and plasma [K+] to control levels. Acetazolamide plus furosemide also restored the cortical expression of BK-β4 and BK-α in connecting tubules. These results indicate that in mice adapted to HK, furosemide reduces BK-αβ4-mediated K+ secretion by acidifying the urine.