Asymptomatic bacteriuria among the elderly residents of long-term care facilities in Taiwan

Urine neutrophil gelatinase-associated lipocalin as a biomarker of adult pyelonephritis

BACKGROUND

Pyelonephritis is a common infection at any age. Urine neutrophil gelatinase-associated lipocalin (NGAL), a novel biomarker of acute renal failure, is related to pyelonephritis in pediatric patients, although the significance of this urine biomarker in adult patients are not clear. We investigated the relationship between urine NGAL of pyelonephritis and non-pyelonephritis.

PATIENTS AND METHODS

We prospectively enrolled adult patients who were hospitalized due to pyelonephritis or non-pyelonephritis. Pyelonephritis was diagnosed in patients with fever and bacteriuria, with no any other infection focuses. Non-pyelonephritis was diagnosed in patients who had fever and another infection focus without bacteriuria. Urine samples were collected on days 0, 3 and 7. Urine NGAL levels were measured by ELISA.

RESULTS

There were 35 patients in the pyelonephritis group and 19 patients in the non-pyelonephritis group. Urine NGAL level were significantly higher in the pyelonephritis group than the non-pyelonephritis group on day 0 (median 302 ng/mL vs 25 ng/mL, p = 0.006). The area under the receiver operating characteristic curve of NGAL was 0.78 (p = 0.006). Urine NGAL level had a specificity of 66.7% and sensitivity of 87.0% at the cut-off level of 250 ng/mL for diagnosing pyelonephritis.

CONCLUSIONS

Urine NGAL level at the diagnosis of infection are elevated in adult patients with pyelonephritis, but not in those with non-pyelonephritis. Urine NGAL might be a supportive biomarker for the diagnosis of pyelonephritis.

Insight into infection-mediated prostate damage: Contrasting patterns of C-reactive protein and prostate-specific antigen levels during infection

BACKGROUND

To investigate mechanisms underlying our previous observation of a large rise in serum prostate-specific antigen, a marker of prostate pathology, during both sexually transmitted and systemic infections, we measured serum high-sensitivity C-reactive protein (hsCRP), a marker of systemic inflammation, in our previous case-control study of young, male US military members and compared our findings to those for PSA.

METHODS

We measured hsCRP before and during infection for 299 chlamydia, 112 gonorrhea, and 59 non-chlamydial, non-gonococcal urethritis (NCNGU) cases; before and after infection for 55 infectious mononucleosis (IM) and 90 other systemic/non-genitourinary cases; and for 220-256 controls.

RESULTS

Only gonorrhea cases were significantly more likely to have a large hsCRP rise (≥1.40 mg/L or ≥239%) during infection than controls (P < 0.01). However, gonorrhea, IM, and other systemic/non-genitourinary cases were more likely to have a rise of any magnitude up to one year post-diagnosis than controls (p = 0.038-0.077).

CONCLUSIONS

These findings, which differ from those for PSA, suggest distinct mechanisms of elevation for hsCRP and PSA, and support both direct (eg, prostate infection) and indirect (eg, systemic inflammation-mediated prostate cell damage) mechanisms for PSA elevation. Future studies should explore our PSA findings further for their relevance to both prostate cancer screening and risk.