Urinary tract infections in culled sows from Greek herds: prevalence and associations between findings of histopathology, bacteriology and urinalysis

Abstract

Background Urinary tract infections (UTI) of sows characterized by cystitis, which may progress to ureteritis and pyelonephritis, can affect their productivity, longevity and welfare. In this study, we determined the prevalence of UTI by histopathology and bacteriology. Furthermore, we investigated possible associations between histologically confirmed cystitis and the results of urinalysis and urine cultures in culled sows from three farrow-to-finish herds in Greece. Materials and methods One hundred eighty-five routinely culled sows were included in the study. Their urinary bladder was collected from abattoirs and subjected to histopathology. Furthermore, urinalysis and urine cultures were performed on urine samples aseptically collected from the bladders. Results Histologically confirmed cystitis was evident in 85/185 (45.94%) culled sows. Among those, 44 (51.76%) suffered from acute and 41 (48.24%) from chronic inflammation. The majority of positive urine cultures were due to colonization of the urinary tract with E.coli, which accounted for 55.81% of the total cases, followed by Staphylococcus spp. which accounted for 18.60% of detected infections. Evidence of cystitis was associated with bacteriuria and sows with bacteriuria were 2.30 (P = 0.03, 95% CI: 1.10–4.83) times more likely to have histologically confirmed cystitis compared to sows with negative urine cultures. Bacteriuria was associated with proteinuria (P < 0.01, OR = 9.72, 2.63–35.88), increased urine pH (P < 0.01, 3.40, 1.10–10.56) and presence of sediment (P < 0.01, 6.00, 1.50–23.76) in urine. Sows with proteinuria had 9.72 (P < 0.01, 2.63–35.88) times higher odds of bacteriuria than those without. Histologically defined cystitis was associated with proteinuria (P < 0.01, 2.03–13.20) and decreased urine pH (P < 0.01, 0.13–0.72). Sows with proteinuria were 5.18 (P < 0.01, 2.03–13.2) times more likely to have histological lesions consistent with cystitis, than those without. For one unit increase in pH, it was 3.20 (P = 0.006, 1.39–7.69) times less likely for a sow to have chronic or acute cystitis compared to absence of cystitis. Conclusion In the studied population, UTI affected almost one out of two culled sows. Bacteriuria, which was more common among sows with UTI than those without, was mainly ascribed to members of the intestinal and environmental bacteria. Proteinuria and the existence of urine sediment which were associated with UTI, could be used as proxy traits for UTI in live sows.

Reproductive health of the sow during puerperium

“…A meaningful diagnostic workup may include an initial ultrasound examination of the urinary bladder that is followed by collecting a urine sample for urine analysis. In a recent study in Greece (Cernat et al, 2021), histologically defined cystitis was associated with proteinuria and decreased urine pH. Sows with proteinuria were 5.2 times more likely to have histological lesions consistent with cystitis compared with sows without proteinuria.…”

“…The source of pathological vulvar discharge may be a disease of the reproductive or urinary tract, for example, endometritis or cystitis. Infections of the urogenital tract affect almost one in two culled sows (Bellino et al, 2013;Cernat et al, 2021;Tolstrup, 2017). In sows culled because of reproductive failure, cystitis and endometritis can be found in up to 90% (Sipos et al, 2014).…”

“…In sows culled because of reproductive failure, cystitis and endometritis can be found in up to 90% (Sipos et al, 2014). Cystitis and endometritis are mainly ascribed to members of the intestinal and environmental bacteria (Bellino et al, 2013;Biksi et al, 2002;Cernat et al, 2021;Oravainen et al, 2008;Sipos et al, 2014;Tummaruk et al, 2010). The bacteria can also live among the normal physiological microbiota on the skin and mucosa of the lower female reproductive tract (Glock & Bilkei, 2005;Oravainen et al, 2008;Tummaruk et al, 2010).…”

Cystitis: significant associations between pathology, histology, and quantitative bacteriology in sows, a cross-sectional study

“…The definition of cystitis in sows has not been standardized. Various criteria, including bacteriuria [ 13 – 17 ], demonstration of nitrite and/or blood using reagent strip tests [ 18 ], macroscopic pathology [ 13 , 15 , 16 , 19 – 22 ], histopathology [ 13 , 16 , 17 , 20 , 23 ] and ultrasound examination have been used as indicators of cystitis/UTI. A resent review suggested that a diagnostic workup may include an initial ultrasound examination of the urinary bladder that is followed by collecting a urine sample for urine analysis [ 24 ].…”

“…A resent review suggested that a diagnostic workup may include an initial ultrasound examination of the urinary bladder that is followed by collecting a urine sample for urine analysis [ 24 ]. Earlier studies have reported a variable prevalence of cystitis ranging between 27 and 53% based on histopathology [ 13 , 16 , 20 , 23 ], between of 12.2 and 68% based on macroscopic pathological changes [ 13 , 15 , 21 , 22 ], and between 23 and 38% based on bacteriuria [ 13 , 17 , 20 ]. In the studies conducted during the last 20 years E. coli was the predominant species isolated from sow urine [ 13 , 15 , 17 , 21 , 23 , 25 ].…”