Treatment Of Complicated Urinary Infections Research Articles

Antimicrobial resistance patterns of bacterial pathogens recovered from the urine of patients at Canadian hospitals from 2009 to 2020.

To investigate in vitro susceptibility patterns of bacterial pathogens recovered from the urine of outpatients (isolates from outpatient clinics or emergency departments) and hospital inpatients across Canada from 2009 to 2020 as part of the CANWARD study. Canadian hospital microbiology laboratories submitted bacterial pathogens cultured from urine to the CANWARD study coordinating laboratory on an annual basis (January 2009 to December 2020). Antimicrobial susceptibility testing was performed by CLSI broth microdilution, with MICs interpreted by current CLSI breakpoints. In total, 4644 urinary pathogens were included in this study. Escherichia coli was recovered most frequently (53.3% of all isolates), followed by Enterococcus faecalis, Klebsiella pneumoniae, Proteus mirabilis, Pseudomonas aeruginosa and Staphylococcus aureus. Together, these six species accounted for 84.2% of study isolates. Nitrofurantoin demonstrated excellent in vitro activity versus E. coli, with 97.6% of outpatient and 96.1% of inpatient isolates remaining susceptible. In contrast, E. coli susceptibility rates were lower for ciprofloxacin (outpatient 79.5%, inpatient 65.9%) and trimethoprim/sulfamethoxazole (outpatient 75.2%, inpatient 73.5%). The percentage of E. coli isolates that were phenotypically positive for ESBL production significantly increased from 4.2% (2009-11) to 11.3% (2018-20). A similar although less pronounced temporal trend was observed with ESBL-producing K. pneumoniae. E. coli was the pathogen most frequently recovered from the urine of Canadian patients, and the proportion of isolates that were ESBL producers increased over time. Susceptibility data presented here suggest that ciprofloxacin and trimethoprim/sulfamethoxazole may be suboptimal for the empirical treatment of complicated urinary infections.

Best pharmacological practice: urinary tract infections

Urinary tract infection is the most frequent bacterial infection. Acute uncomplicated urinary infection and acute non-obstructive pyelonephritis occur in young women with normal genitourinary tracts. Empirical short-course therapy is preferred for the management of acute cystitis, but evolving resistance requires continuing reassessment of optimal antimicrobial selection. Empirical trimethoprim or trimethoprim/sulfamethoxazole has been recommended, but increasing resistance to these agents suggests that pivmecillinam, nitrofurantoin and perhaps fosfomycin trometamol should be considered. Although flouroquinolones are effective as short-course therapy, widespread empirical use of these agents should be discouraged because of potential promotion of resistance. For acute non-obstructive pyelonephritis, flouroquinolones are the empirical oral treatment of choice, although urine culture results should direct continuing therapy. Complicated urinary tract infection occurs in men or women of all ages with underlying abnormalities of the genitourinary tract. Treatment of complicated urinary infection is individualised, taking into consideration the underlying abnormality and susceptibilities of the infecting organism. Asymptomatic bacteriuria should not be treated except in pregnant women, in patients prior to undergoing an invasive surgical procedure, or renal transplant recipients in the early postrenal transplant period.

Pathogenesis of bacteriuria and infection in the spinal cord injured patient

Spinal cord injury (SCI) produces profound alterations in lower urinary tract function. Incontinence, elevated intravesical pressure, reflux, stones, and neurological obstruction, commonly found in the spinal cord-injured population, increase the risk of urinary infection. The overall rate of urinary infection in SCI patient is about 2.5 episodes per patient per year. Despite improved methods of treatment, urinary tract morbidity still ranks as the second leading cause of death in the SCI patient. SCI removes the ability of the pontine micturition center and higher centers in the brain to inhibit, control, or coordinate the activity of the vesicourethral unit. As a result, a patient with complete quadriplegia is typically unaware of bladder activity. Bladder contraction is accompanied by vesicosphincter dyssynergia instead of sphincter relaxation. It is widely accepted that intermittent catheterization, when compared with indwelling catheters, reduces the risk of urinary tract infection (UTI) in SCI patients and is the preferred method of bladder drainage in this patient population. Attempts at eliminating bacteriuria associated with indwelling or intermittent catheters have generally been unsuccessful. There is now appreciation of the fact that a creeping adherent biofilm of bacteria frequently ascends through the luminal and external surfaces of an indwelling catheter, often within 8 to 24 hours, leading to bacterial adherence to the bladder surface and correlating with symptomatic infection. The use of antimicrobial agents to clear or prevent bacteriuria in patients on indwelling or intermittent catheterization has had mixed success. Treatment for asymptomatic bacteriuria in SCI patients remains controversial. SCI patients with symptomatic urinary infections should be treated with the most specific, narrowest spectrum antibiotics available for the shortest possible time. Guidelines for selecting antimicrobial agents in SCI patients are similar to guidelines for the treatment of complicated urinary infections in the general population. Characteristics of the quinolones make them well suited to treating UTI in the SCI patient.