Urinary AntibiogramPrototype

What this is

A weighted urinary antibiogram, not a formal WISCA. Each regimen's coverage is the isolate-frequency-weighted average of its per-organism susceptibility: Σ (organism weight × %S). It prices in the pathogen mix the per-bug grid hides.

Susceptibility grid view

The grid is the raw urinary antibiogram for the selected setting: observed % susceptible per organism, R for intrinsic resistance, — for untested / too few isolates. No weighting, imputation, or surrogate estimation — it is the source the weighted view is built from.

Route grouping & oral aminopenicillins

Oral aminopenicillins are estimated from their lab-tested equivalents (equivalent spectra): amoxicillin from ampicillin, amoxicillin-clavulanate from ampicillin-sulbactam. The parenteral ampicillin and ampicillin-sulbactam rows show the same underlying figures.

“Typical cystitis pathogens” is a proxy, not a definition

This view restricts the organism mix to E. coli, K. pneumoniae, and P. mirabilis and reweights by their isolate frequency — it is not an encounter-level filter and not the IDSA 2025 symptom-based definition of uncomplicated cystitis (which turns on localized vs systemic symptoms at the point of care). The antibiogram carries no host or symptom data, only specimen source; outpatient and emergency-dept approximate the community population, inpatient does not. Dropping Enterococcus and Pseudomonas is a crude stand-in for excluding asymptomatic bacteriuria and colonization, which inflate those two organisms in urine cultures. S. saprophyticus is absent from the source table — a canonical uncomplicated-cystitis pathogen (especially in younger women), so this view is biased where it matters.

not_reported handling (weighted view)

• Intrinsic resistance → 0% (e.g. Proteus vs nitrofurantoin).
• Imputed 0 (real empiric gap): cephalosporins, fluoroquinolones, and aminoglycoside monotherapy vs Enterococcus; nitrofurantoin vs Pseudomonas; carbapenems vs Enterococcus (meropenem is not reliable enterococcal therapy).
• Credited via ampicillin: all local E. faecalis are ampicillin-susceptible, so ampicillin-sulbactam, amoxicillin-clavulanate, and piperacillin-tazobactam count them as covered.
• Meropenem vs Proteus is estimated from ertapenem (carbapenem class, 100% locally). Ertapenem is not shown in the weighted view — it covers neither Pseudomonas nor Enterococcus (it is still in the grid).

Confidence bands

Wilson interval on the weighted estimate via an effective sample size: variance = Σ w²·p(1−p)/n, n₋ = p̂(1−p̂)/variance. Structural gaps (intrinsic R, imputed 0) carry no sampling variance, so a figure dominated by them shows a narrow band around the tested fraction.

Limits to keep in mind

• Weights are urine-isolate frequencies, not UTI incidence. Asymptomatic bacteriuria and colonization inflate Enterococcus and Pseudomonas, so the all-isolates view understates coverage for true cystitis.
• Point estimates from aggregate %S — no isolate line list, so combination-regimen coverage and co-resistance are not computable. Monotherapy only.
• Fosfomycin and oral cephalosporins are not on the local antibiogram (see the fosfomycin row).

Source: local antibiogram, 2025 urinary isolates (de-identified). Fosfomycin national figure: PubMed 28285420. Prototype — verify against the source antibiogram before any clinical use.