E. COLI - URINARY TRACT INFECTION
LEVELS: Highly unlikely: No controls necessary; Highly unlikely: No evidence of non-foodborne zoonotic transmission; Highly effective: Routine on-farm biosecurity measures are effective in preventing farm-to-farm transmission; Moderate: Clinical signs not unique but existing tests available at local/regional laboratory(s); Moderate: Manageable losses related to endemic (population) or chronic (individual) occurrence; Negligible: Little or no market disruption when disease occurs on one or more farms; High risk: Resistance to antibacterial or antiviral treatments is, or can be expected to be a common problem; Minimal risk: Antibacterial or antiviral treatments rarely occur, or are typically limited to short-course individual animal therapy; Available but with uncertain efficacy: Limited treatments available in US or are only effective in some situations; No availability: Effective vaccines not currently available in the US (or have not been developed); Not feasible: Eradication extremely unlikely
OVERVIEW
Nonspecific urinary tract infection (UTI) in sows is a non-contagious infectious disease of endogenous origin, with E. coli being the predominant bacterial species (associated with approximately 50-80% of cystitis and pyelonephritis cases). UTI occurs when fecal microbiota ascend the urethra to colonize the bladder. The short, wide urethra of female pigs, relaxation of sphincter muscles during pregnancy and puerperium, and behavioral factors (dog-sitting position, prolonged recumbency) facilitate bacterial ascent. UTI prevalence ranges from 15.8% to 58% depending on diagnostic method. Most cases are subclinical; possible clinical signs include pollakiuria, dysuria, hematuria, polydipsia, and vulvar discharge, though these are often attributed to endometritis. Sows with significant bacteriuria have smaller litters, longer inter-farrowing intervals, lower fertility rates, and inferior body condition. Pyelonephritis, a complication of ascending infection, may lead to death or early culling. Diagnosis requires urinalysis and urine culture (>10^5 CFU/mL indicates infection). Uropathogenic E. coli possess P and S fimbriae facilitating colonization, and toxins (hemolysin, CNF) promoting tissue damage. Prevention focuses on adequate water intake, urinary acidification, and hygiene. No vaccines are available.
FOODBORNE ZOONOTIC TRANSMISSION POTENTIAL
Level: Highly unlikely: No controls necessary
Uropathogenic E. coli causing UTI in sows are not foodborne zoonotic pathogens. These are opportunistic infections without documented human disease transmission through pork consumption.
NON-FOODBORNE ZOONOTIC TRANSMISSION POTENTIAL
Level: Highly unlikely: No evidence of non-foodborne zoonotic transmission
UTI-causing E. coli strains are not zoonotic to humans through direct contact. While human UTI is commonly caused by E. coli, porcine and human uropathogenic strains are distinct populations.
EFFECTIVENESS OF ON-FARM BIOSECURITY IN PREVENTING FARM-TO-FARM TRANSMISSION
Level: Highly effective: Routine on-farm biosecurity measures are effective in preventing farm-to-farm transmission
UTI is a non-contagious, endogenous infection: (1) Non-contagious: "infections caused by ExPEC and E. coli causing CM and UTI do not behave as communicable diseases"; (2) Fecal source: "Contamination and ascent of the urethra by fecal microbiota is more likely in females than males"; (3) Risk factors: "Under intensive confinement conditions, vulvas of sows are often placed in direct contact with feces"; (4) Environmental management: Water availability, hygiene, and housing design control risk.
DIFFICULTY OF DETECTING AND CONFIRMING INFECTION
Level: Moderate: Clinical signs not unique but existing tests available at local/regional laboratory(s)
Diagnosis requires laboratory testing: (1) Subclinical majority: "In the vast majority of nonspecific UTI cases, there are no clinical signs"; (2) Clinical examination limited: "Clinical examination of the animal is of little value"; (3) Urinalysis: pH, proteins, nitrates, sediment microscopy; (4) Urine culture: ">10^5 CFU/mL is interpreted as indicative of infection and from 10^4 to 10^5 CFU/mL as suspicious"; (5) Histopathology gold standard: "in dead sows, histopathology is the 'gold standard' for diagnosis."
FINANCIAL IMPACT ON FARM'S COST OF PRODUCTION
Level: Moderate: Manageable losses related to endemic (population) or chronic (individual) occurrence
UTI causes moderate reproductive and production losses: (1) Reproductive impact: "Sows with a significant bacteriuria tend to wean small litters, have increased intervals between litters, show a lower fertility rate, and exhibit an inferior body condition"; (2) High prevalence: "prevalence of UTI...ranging from 15.8 to 58%"; cystitis diagnosed in 45.94% of culled sows in one study; (3) Culling risk: Pyelonephritis "may lead to the death or early culling of sows."
EFFECT ON DOMESTIC OR EXPORT MARKETS
Level: Negligible: Little or no market disruption when disease occurs on one or more farms
No trade implications: (1) Not regulated: UTI is not a reportable or trade-restricted disease; (2) Sow-level disease: Does not affect market pigs; (3) Indirect effects: Impact through reproductive losses and early culling.
PATHOGEN'S ABILITY TO DEVELOP AND SPREAD RESISTANCE
Level: High risk: Resistance to antibacterial or antiviral treatments is, or can be expected to be a common problem
Uropathogenic E. coli share resistance concerns: (1) Multidrug resistance documented: "Uropathogenic E. coli strains...can exhibit multidrug-resistance phenotypes"; (2) Same mechanisms: As other E. coli populations.
AMR DEVELOPMENT DRIVEN BY DISEASE MANAGEMENT
Level: Minimal risk: Antibacterial or antiviral treatments rarely occur, or are typically limited to short-course individual animal therapy
UTI treatment contributes to antimicrobial use: (1) Treatment frustrating: "Treatment of urogenital infections of swine can be frustrating"; (2) Variable susceptibilities: "therapy with broad-spectrum or combined antimicrobials is recommended due to the variable susceptibilities"; (3) Prolonged treatment may be needed: "Prolonged parenteral treatment may be recommended, although subclinical UTI often persists after treatment."
AVAILABILITY OF EFFECTIVE TREATMENT OPTIONS
Level: Available but with uncertain efficacy: Limited treatments available in US or are only effective in some situations
Treatment available but persistence common: (1) Antimicrobials: Broad-spectrum or combined antimicrobials recommended; (2) Prolonged treatment: May be needed but "subclinical UTI often persists after treatment"; (3) Pre-farrowing treatment: "Treatment of affected sows with specific antimicrobial drugs before parturition may be helpful."
AVAILABILITY OF EFFECTIVE VACCINES OR BACTERINS
Level: No availability: Effective vaccines not currently available in the US (or have not been developed)
No vaccines available: (1) Limited immunity: Serum antibodies may be present but "E. coli strains may persist in the urinary tract despite high antibody concentrations in the urine"; (2) Prevention focus: Water intake, urinary acidification, hygiene.
FEASIBILITY OF ERADICATING THE DISEASE FROM THE US
Level: Not feasible: Eradication extremely unlikely
Eradication is not feasible: (1) Endogenous origin: Fecal microbiota is the source; (2) Ubiquitous E. coli: Normal intestinal flora; (3) Risk factor management: Focus is on increasing urination frequency, improving hygiene, and reducing fecal contamination.