Urinary neutrophil gelatinase-associated lipocalin, kidney injury molecule-1, uromodulin, and cystatin C concentrations in an experimental rat model of ascending acute kidney injury induced by pyelonephritis.

Recent evidence suggests that neutrophil gelatinase-associated lipocalin (NGAL), kidney injury molecule-1 (KIM-1), cystatin C (CysC), uromodulin (UMOD), and some interleukins (IL-6 and IL-18) can be considered as diagnostic markers of acute kidney injury (AKI). The aim of this study was to verify the applicability of four urinary (u) markers, namely uNGAL, uKIM-1, uCysC, and uUMOD, for the diagnosis of ascending AKI induced by bacterial pyelonephritis. The study included 30 female rats that were divided into three groups (n = 10 each) and were inoculated transurethrally with various doses of Escherichia coli to induce isolated pyelonephritis (group 1, 105 CFU/ml), pyelonephritis-induced AKI (group 2, 107 CFU/ml), or AKI and urosepsis (group 3, 109 CFU/ml). The inoculate contained a highly virulent E. coli strain isolated from a patient with pyelonephritis. Urine samples were obtained prior to the inoculation and 7, 14, and 21 days thereafter. The concentrations of all assessed proteins were determined in the urine samples by ELISA. All the study groups showed elevated concentrations of uNGAL and uCysC at all study time points. The concentrations of uKIM-1 in group 1 were the same as that at the baseline, whereas it was elevated in groups 2 and 3 at all study time points. The concentrations of uUMOD in groups 1 and 2 tended to decrease with the time from inoculation, whereas it rapidly increased in group 3 at 21 days postinfection. uKIM-1 seems to be the only marker of ascending AKI associated with urinary tract infection. Elevated concentrations of uNGAL, uCysC, and uUMOD were found in both AKI and isolated pyelonephritis. Thus, it can be concluded that none of these markers can be used as a single diagnostic marker of ascending AKI, as it may produce false-negative results, leading to incorrect diagnosis, lack of adequate treatment, and increased mortality risk.

Virulence factors of Streptococcus pyogenes strains from women in peri-labor with invasive infections.

Invasive group A streptococcal (GAS) infections constitute an important epidemiological problem. Many cases occur in women during the postnatal period. The objective of this study was to evaluate the presence of the genes responsible for production of iron-chelating protein (perR) and superantigens (speA, speB, speC, speF, speG, speH, speI, speJ, speK, speL, speM, smeZ, and ssa) in S. pyogenes strains isolated from invasive infections in women after delivery. Furthermore, this study sought to verify whether S. pyogenes strains show special phenotypic and genotypic (sla, spy1325) characteristics that may play a decisive role in adherence to the genital tract epithelium. Moreover, the emm-types and antibiotic susceptibility were determined. We tested 30 invasive S. pyogenes strains isolated from postpartum invasive infection and 37 GAS control strains isolated from the genital tracts of asymptomatic multiparous women. The majority of the tested strains were shown to express two types of emm genes (1 and 28), though emm -12, -28, -75 and -89 were uniquely expressed in the group of strains isolated from invasive infections. A significantly higher prevalence of perR in the strains from puerperal fever was shown. Significant differences were also found between the two groups with respect to the incidence of the genes related to adherence; GAS strains originating from women with sepsis/puerperal fever showed presence of these genes less frequently than those of the control group. Although differences in frequencies of the gene coding for various superantigens were noted between the compared groups of GAS strains, they were not significant.