OmegaacademixBackground
When a manufacturer discontinued cefixime in 2002, many pediatric centers were left searching for a comparably convenient oral cephalosporin to treat community-acquired urinary tract infections (UTIs) in children. At one urban tertiary academic pediatric emergency department, cefdinir — already FDA-approved for skin and respiratory infections ,stepped in as an off-label substitute. But until recently, no direct susceptibility data existed to confirm whether that substitution made clinical sense.
A retrospective study conducted at Columbus Children's Hospital, published in Academic Emergency Medicine, set out to close that gap. Researchers reviewed a full year of urine culture and susceptibility data from children evaluated for UTI in the emergency department, comparing cefdinir's performance against a panel of commonly used oral and parenteral antibiotics.
Study Snapshot
Between April 2003 and April 2004, 705 urine samples grew a bacterium at the study site. After excluding contaminants, mixed-flora growth, duplicate samples, and specimens with low colony counts or patients over 18, the final analysis included 431 uropathogens from 424 children (median age just under 5 years, 87% female). E. coli was by far the most common isolate (86%), followed by Klebsiella, Proteus, and smaller numbers of other organisms.
Isolates were split into two clinically meaningful groups: 414 pathogens typically responsible for uncomplicated, community-acquired UTIs (E. coli, Klebsiella, Proteus mirabilis, and S. saprophyticus), and 17 isolates linked to opportunistic or nosocomial infections — organisms more often seen in hospitalized children or those with urologic complications.
Key Findings
Across the full sample, cefdinir was active against 95.6% of isolates — a rate on par with nitrofurantoin (93.3%) and well ahead of ampicillin (49.4%) and trimethoprim-sulfamethoxazole (84.9%). Among parenteral comparators, ceftriaxone (97.7%) and gentamicin (97.5%) edged cefdinir out slightly, though the study authors noted the gap was small and unlikely to be clinically meaningful.
The picture became more nuanced when isolates were split by infection type. For the 414 community-acquired pathogens. the population most relevant to typical outpatient prescribing — cefdinir susceptibility rose to 96.9%, and against E. coli specifically it reached 98.4%, essentially matching ceftriaxone and gentamicin.
Cefdinir's performance dropped off considerably against the 17 opportunistic isolates, where susceptibility fell to 64.7%. Trimethoprim-sulfamethoxazole, gentamicin, ceftriaxone, and ticarcillin-clavulanate all outperformed cefdinir in this smaller, higher-risk subgroup, while ampicillin and cefazolin performed poorly across the board for these organisms.
Susceptibility Data at a Glance
Overall susceptibility across all 431 isolates:
| Antimicrobial | Susceptible | Indeterminate | Resistant |
|---|---|---|---|
| Cefdinir | 95.6% | 0% | 4.4% |
| Ampicillin | 49.4% | 0.5% | 50.1% |
| Nitrofurantoin | 93.3% | 1.9% | 4.9% |
| Trimethoprim–sulfamethoxazole | 84.9% | 0.2% | 14.8% |
| Gentamicin | 97.5% | 0% | 2.5% |
| Ticarcillin–clavulanate potassium | 94.2% | 4.9% | 0.9% |
| Ceftriaxone | 97.7% | 0.5% | 1.9% |
| Cefazolin | 88.4% | 4.4% | 7.2% |
Susceptibility by infection type:
| Antimicrobial | Community-Acquired (n=414) | Opportunistic (n=17) |
|---|---|---|
| Cefdinir | 96.9% | 64.7% |
| Ampicillin | 51.2% | 5.9% |
| Nitrofurantoin | 94.2% | 70.6% |
| Trimethoprim–sulfamethoxazole | 84.8% | 88.2% |
| Gentamicin | 97.6% | 94.1% |
| Ticarcillin–clavulanate potassium | 94.4% | 88.2% |
| Ceftriaxone | 98.1% | 88.2% |
| Cefazolin | 91.6% | 11.8% |
Community-acquired group: E. coli, Klebsiella spp, P. mirabilis, S. saprophyticus. Opportunistic group: Enterobacter, Citrobacter, Enterococcus, Serratia, Hafnia, and Morganella species.
Why This Matters for Practice
For pharmacists and trainees, the practical takeaway is one of appropriate patient selection rather than a blanket endorsement. In previously healthy children with uncomplicated, community-acquired UTIs, this data supports cefdinir as a reasonable empiric oral option — it's conveniently dosed once or twice daily, generally well tolerated, and reported to be more palatable than several alternative oral suspensions, which matters considerably for pediatric adherence.
The authors were explicit, however, that cefdinir should be avoided as empiric therapy in children with indwelling catheters, known urologic abnormalities, or UTIs arising after hospitalization, instrumentation, or urinary tract surgery — precisely the population where opportunistic organisms are more likely and where susceptibility dropped sharply in this dataset.
As with any single-site retrospective analysis, the authors called for prospective trials to confirm that in vitro susceptibility translates into real-world clinical cure, and for cost-effectiveness comparisons against antibiotics not routinely tested at their site, such as cephalexin.
Takeaway
This study adds pediatric-specific evidence to a growing body of data — alongside adult studies from Sader et al. and Leigh et al. supporting cefdinir as a viable, off-label option for uncomplicated community-acquired pediatric UTIs, while reinforcing that it is a poor empiric choice when opportunistic or nosocomial pathogens are suspected.
Source: Bonsu BK, Shuler L, Sawicki L, Dorst P, Cohen DM. Susceptibility of Recent Bacterial Isolates to Cefdinir and Selected Antibiotics among Children with Urinary Tract Infections. Academic Emergency Medicine. 2006;13:76-81.
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