BSAC User Group Meeting 2007 BSAC recommendations for interpreting the susceptibility of urinary tract isolates Jenny Andrews

BSAC User Group Meeting 2007 UTIs Frequency of micturition DysuriaUrgency Suprapubic pain PyrexiaPyelonephritis

BSAC User Group Meeting 2007 Bacterial causes of UTIs Organism Community Acquired (%) Hospital Acquired (%) E. coli 7540 P. mirabilis 310 Other coliforms 525 P. aeruginosa 15 E. faecalis 58 S. saprophyticus 51 S. epidermidis 23

BSAC User Group Meeting 2007 Non-bacterial causes of UTIs

BSAC User Group Meeting 2007 Simple UTIs Women of child-bearing age E. coli P. mirabilis KlebsiellaeEnterococci S. saprophyticus Group B Streptococci

BSAC User Group Meeting 2007 Prevalence of organisms isolated from samples taken in the community (female) City Hospital data

BSAC User Group Meeting 2007 Complicated UTIs Male patients Abnormal anatomy CatheterisationChildren Immunocompromised patients Elderly

BSAC User Group Meeting 2007 Microbial causes EnterobacteriaceaeNon-fermentersStaphylococciEnterococci Antibiotic-resistant strains frequently isolated

BSAC User Group Meeting 2007 UTI in men Age group (years)Incidence(%)Comment 20-60<1 Very uncommon. Occur in young men who participate in anal sex, who are not circumcised or whose sexual partner is colonised with uropathogens >8010 Wallach, 2001; McMurdo and Gillespie, 2000

BSAC User Group Meeting 2007 Conditions associated with or predisposing to lower UTI in men Prostatitis/Prostate enlargement (common in older men) Abnormal urinary tract, anatomical changes,calculi and tumours Impaired host defences Impaired renal function Bailey 1996

BSAC User Group Meeting 2007 E.coli the most common pathogen in acute and chronic prostatitis Klebsiella spp. and P. mirabilis isolated less frequently Hospital acute cases may involve staphylococci and occasionally enterococci or Pseudomonas spp UTI in men – organisms associated with infection

BSAC User Group Meeting 2007 Prevalence of organisms isolated from samples taken in the community (male) City Hospital data

BSAC User Group Meeting 2007 Laboratory diagnosis Mid Stream Urine Low epithelial cell count Pyuria/haematuria Semi-quantitative culture 10 5 cfu/ml bacteria considered significant Identification (some laboratories do not ID urine isolates) and susceptibility testing

BSAC User Group Meeting 2007 BSAC: Systemic recommendations Non-species specific Table 6: MIC and zone breakpoints for Enterobacteriaceae (including Salmonella and Shigella spp.). MIC breakpoint (mg/L) Interpretation of zone diameters (mm) AntibioticR >I S  Disc content (µg) R  I S  Amikacin Amoxicillin Ampicillin Aztreonam Cefaclor Cefamandole 4, Cefepime Cefixime

BSAC User Group Meeting 2007 BSAC: Species specific breakpoints for simple UTIs Interpretation of zone diameters (mm) MIC breakpoint (mg/L)ColiformsEscherichia coliProteus mirabilis AntibioticR >I S  Disc content (µg) RR I SS RR I SS RR I SS Amoxicillin Ampicillin Cefalexin Ciprofloxacin Co-amoxiclav32- 20/ Fosfomycin 7, / Mecillinam Nalidixic acid Nitrofurantoin Norfloxacin Temocillin Trimethoprim NB. These recommendations are for organisms associated with uncomplicated urinary tract infections. For complicated infections systemic recommendations should be used.

BSAC User Group Meeting 2007 Interpretation of zone diameters (mm) MIC breakpoint (mg/L) EnterococciStaphylococcus saprophyticus Group B streptococci AntibioticR >I S  Disc content (µg) R  I S  R  I S  RR I Ampicillin Cefalexin Ciprofloxacin Ciprofloxacin Co-amoxiclav32- 20/ Fosfomycin / Mecillinam Nalidixic acid Nitrofurantoin Norfloxacin Trimethoprim NB. These recommendations are for organisms associated with uncomplicated urinary tract infections. For complicated infections and infections caused by Staphylococcus aureus and Staphylococcus epidermidis, which are associated with more serious infections, systemic recommendations should be used. BSAC: Species specific breakpoints for simple UTIs

BSAC User Group Meeting 2007 Organism Identification Essential for interpretation of susceptibility Chromogenic media

BSAC User Group Meeting 2007 Chromogenic agar (6570 UTI) Klebsiella-Enterobacter-Serratia 28.6% Proteus-Morganella-Providencia 6.9% 72.5% Data presented by Trevor Winstanley at User Group meetings in 2005 (Power Point presentation available on the BSAC web site (

BSAC User Group Meeting 2007 Footnotes to the UTI tables

BSAC User Group Meeting 2007 BSAC recommendations The recommendations are for organisms associated with uncomplicated urinary tract infections For complicated infections systemic recommendations should be used For infections caused by S. aureus and S. epidermidis, which are associated with more serious infections, systemic recommendations should be used

BSAC User Group Meeting 2007 BSAC recommendations If an organism is isolated from multiple sites, for example from blood and urine, interpretation of susceptibility should be made with regard to the systemic site. Direct susceptibility tests on urine may be performed as long as the inoculum gives semi-confluent growth.

BSAC User Group Meeting 2007 BSAC recommendations In the absence of definitive organism identification, use the recommendations most appropriate for the presumptive identification, accepting that on some occasions the interpretation may be incorrect. A more cautious approach is to use systemic recommendations

BSAC User Group Meeting 2007 BSAC recommendations The identification of Enterobacteriaceae to species level is essential before applying expert rule for the interpretation of susceptibility e.g. recommendations for ampicillin/amoxicillin are for E. coli and P. mirabilis not for species that have chromosomal penicillinase (Klebsiella spp.) or those that typically have inducible AmpC enzymes (e.g. Enterobacter spp., Citrobacter spp. and Serratia spp.)

BSAC User Group Meeting 2007 Under review by EUCAST/BSAC Use of trimethoprim for the treatment of enterococci The clinical efficacy of mecillinam in the treatment of ESBL infections

BSAC User Group Meeting 2007 Gaps in the “Coliform” recommendations “Coliform” means like an E. coli, the recommendations should not be used for Enterobacter spp. etc. ID to species level is essential for the correct interpretation

BSAC User Group Meeting 2007 Should nalidixic acid be used to detect FQ resistance? Using nalidixic acid alone 25-40% of isolates with LLR will be reported resistant to ciprofloxacin Organisms with LLR are probably susceptible in uncomplicated infections because of the high concentration of drug in urine

BSAC User Group Meeting 2007 Summary BSAC urinary breakpoints are for simple UTIs For complicated infections systemic recommendations should be used ID is necessary for the interpretation of susceptibility and the application of expert rules (see the Power Point presentation on the BSAC web site for the User Group Meeting in 2005 Trevor Winstanley “Expert rules and inexpensive identification methods”) EUCAST are preparing a document on expert rules that should be available at the end of the year