POSTER ABSTRACTS

Abstract

Urinary tract infections (UTIs) are one of the commonest reasons for hospital admission. Studies have demonstrated wide variation in treatment and indiscriminate use of third generation cephalosporins (ceftriaxone).1 The aims of this study were to assess whether antibiotic use was in keeping with current guidelines and explore the possibility of minimizing third generation cephalosporin use based on local antimicrobial susceptibility patterns. In addition, the study assessed the clinical utility of bedside urinalysis. Data was collected for men and non-pregnant women aged ≥18 admitted to the Angliss Hospital under the General Medicine Unit with a diagnosis of UTI between January and August 2015. 243 patient records were reviewed (mean age 69 ± 21 years, female 80%). UTI was uncomplicated in 177 (73%), complicated (i.e. associated with urological abnormalities) in 49 (20%) and catheter-associated (CAUTIs) in 17 (7%). A positive urine culture was present in 172 (71%), 131 (74%), 35 (71%) and 6 (35%) uncomplicated, complicated and CAUTIs respectively. Despite strong clinical suspicion of UTI, 44 patients (18%) grew mixed flora and 27 (11%) yielded no growth. Among those with a positive culture, Escherichia coli was identified in 133 (77%), 101 (77%) of uncomplicated, 31 (89%) of complicated and 1 (16%) of CAUTI. This was sensitive to first generation cephalosporins (cephazolin) in 88 (87%) uncomplicated and 24 (77%) complicated UTIs, however, the isolate was resistant in the CAUTI. 80% of the 21 E. coli isolates that were resistant to cephazolin were also resistant to ceftriaxone. Other pathogens included Enterococcus faecalis (6%); ESCAPPM organisms (6%); Klebsiella spp and Proteus mirabilis (6%, all sensitive to cephazolin) and Pseudomonas aeruginosa. Antibiotic choice was consistent with guidelines in 76 (43%) uncomplicated, 9 (18%) complicated and 4 (24%) CAUTIs. Ceftriaxone was the first line antibiotic used in 110 (45%) patients. Ceftriaxone use among patients who yielded a positive culture was 81 (47%) whereas 56 (69%) patients (39 (72%) uncomplicated and 17 (65%) complicated) could have potentially been treated with first generation cephalosporins based on their sensitivity results. In culture-positive cases, the finding of a positive leucocyte test on dipstick had a sensitivity of 90.6% and specificity of 20.8%. Nitrite positivity had the highest specificity (78.6%) but sensitivity was 43.9%. Our findings confirm poor adherence to guidelines as well as the indiscriminate use of third generation cephalosporins (ceftriaxone) when treating all types of UTIs. When parenteral antibiotics are indicated, first generation cephalosporins may be a safe first line treatment option for most uncomplicated and complicated UTIs. Furthermore, given the sensitivity patterns, ceftriaxone use in this setting may improve treatment efficacy only marginally. Clinical utility of urine dipstick was modest, which is consistent with previous studies.2