Infectious Diseases — New This Month — August 5

A guideline-heavy three weeks. Six IDSA guidelines/position papers published in a single CID supplement issue — the updated AMR Gram-Negative Treatment Guidance (ESBL-E through CRAB), a comprehensive cUTI guideline (5 parts covering antibiotic selection, IV-to-oral transition, and duration), a COVID-19 antiviral update, GAS pharyngitis risk assessment, and immunocompromised vaccination guidelines — plus a multisociety sepsis position paper outlining hospital-level strategies. Beyond guidelines, a novel RNA-NAAT for C. difficile simultaneously outperforms both DNA-NAAT sensitivity and toxin EIA specificity, and a retrospective cohort reveals that 19% of CDI presents without diarrhea — with atypical dysmotility-first presentations carrying 2.6× higher mortality.

Clinical Infectious Diseases

IDSA Guideline updates

CIDGuideline · AMRHigh yield · ID

IDSA 2026 Guidance on the Treatment of Antimicrobial-Resistant Gram-Negative Infections

What are the preferred and alternative agents for ESBL-E, AmpC-E, CRE, DTR Pseudomonas, CRAB, and S. maltophilia infections in 2026?

What changedComplete replacement of all prior AMR guidance versions. Question-and-answer format covering preferred and alternative agents for 6 resistant gram-negative pathogen groups, with empiric therapy, oral step-down, and duration suggestions. Current as of March 2026. Key recommendationAgent selection driven by pathogen identification + in vitro susceptibility data. Suggestions incorporate newer agents (ceftazidime-avibactam, meropenem-vaborbactam, imipenem-relebactam, cefiderocol, sulbactam-durlobactam) with specific roles by resistance mechanism. Geographic variability addressed (US-focused). Fellow implicationThis is THE reference document for AMR treatment decisions. Bookmark and consult per-pathogen — the field moves too fast for memorization alone.

Anki: not carded — reference document (consult per case, not a single memorizable fact)

CIDGuideline · UTIHigh yield · ID

IDSA 2025 Guidelines on Management and Treatment of Complicated Urinary Tract Infections

How should complicated UTIs be managed — antibiotic selection, IV-to-oral transition timing, and treatment duration?

What changedComprehensive 5-part IDSA guideline covering cUTI from antibiotic selection through duration — replaces the 2010 CAUTI guideline with a broader scope including non-catheter-associated cUTI. Part 2 (antibiotic selection), Part 3 (IV-to-oral transition timing), and Part 4 (treatment duration) contain the actionable recommendations. Key recommendationExpanded definition of cUTI beyond catheter-associated; addresses the 2.8 million US hospitalizations with UTI diagnosis codes. Part 5 incorporates patient perspectives on shared decision-making. Fellow implicationNew standard reference for one of the most common ID consult questions. UTI is the leading cause of gram-negative bacteremia (48% of all GNB).

5 parts: ciaf459 · ciaf460 · ciaf461 · ciaf462 · ciaf463

Anki: not carded — multi-part reference guideline (consult per case)

CIDGuideline · COVID-19High yield · ID

IDSA 2025 COVID-19 Guideline Update: Antiviral Treatment & Baricitinib vs Tocilizumab

In adults with mild-to-moderate COVID-19, which antivirals are recommended — and for hospitalized patients, baricitinib or tocilizumab?

What changed9 updated GRADE recommendations. Nirmatrelvir/ritonavir: strong recommendation for high-risk adults (moderate certainty). Remdesivir: conditional for high-risk when nirmatrelvir/ritonavir is unavailable or contraindicated. Molnupiravir: conditional suggestion against in most patients. Part 2 addresses baricitinib vs tocilizumab for hospitalized patients on supplemental O₂. Fellow implicationConfirms nirmatrelvir/ritonavir as the first-line outpatient COVID-19 antiviral. The antiviral selection algorithm is the key clinical deliverable.

2 parts: ciaf680 · ciaf681

Anki: not carded — confirmatory (nirmatrelvir/ritonavir first-line already established)

CIDPosition Paper · SepsisHigh yield · ID

IDSA/ACEP/ASM/PIDS/SCCM/SHEA/SHM/SIDP Multisociety Position Paper: Hospital Strategies to Improve Sepsis Outcomes

What hospital-level strategies — beyond SSC bedside guidelines — improve infection-related sepsis outcomes?

What changed8-society consensus on hospital infrastructure for sepsis — complements SSC clinical guidelines and the new CMS outcome-based sepsis measures. Covers 6 domains: diagnostics & pathogen detection, antimicrobial management, surveillance & metrics, adjunctive therapy, program infrastructure, and infection prevention. Key recommendationsMultiplex NAAT for positive blood cultures with active stewardship support; β-lactam before vancomycin via clinical decision support; prolonged-infusion antipseudomonal β-lactams in critically ill patients; EHR-based sepsis surveillance; corticosteroid protocols for severe CAP; standardized tooth brushing for VAP prevention. Fellow implicationA blueprint for stewardship and sepsis program building — useful when advocating for institutional resources.

Anki: not carded — hospital-programmatic (not individual clinical decision)

CIDGuideline · GAS PharyngitisHigh yield · ID

IDSA 2025 Guideline on Group A Streptococcal Pharyngitis: Risk Assessment Using Clinical Scoring Systems

Should clinicians use a clinical scoring system (e.g., Centor/McIsaac) to decide who gets tested for GAS pharyngitis?

What changedFirst part of the IDSA GAS pharyngitis guideline update. Conditional recommendation (very low certainty) to use a clinical scoring system to determine who gets tested. Principal utility: identifying patients with low probability of GAS to reduce unnecessary testing. Key recommendationScoring system accuracy is comparable to or slightly higher than clinician judgment alone. High-risk individuals (household GAS exposure, high rheumatic fever risk) should be tested even with low clinical scores.

2 parts: ciaf668 · ciag098

Anki: not carded — conditional recommendation confirming existing practice

CIDGuideline · VaccinesHigh yield · ID

IDSA 2025 Guidelines: Vaccines for COVID-19, Influenza, and RSV in Immunocompromised Patients

When and how should immunocompromised patients receive COVID-19, influenza, and RSV vaccines for the 2025–2026 season?

What changed4-part IDSA/VIP rapid guideline for US-licensed vaccines. Strong recommendations for timely age-appropriate COVID-19, RSV, and influenza vaccination in immunocompromised adults and children (hematologic malignancy, SOT, HSCT, autoimmune on immunosuppressants, advanced HIV). Coadministration of all three considered appropriate. Key recommendationOptimal timing relative to immunosuppressive therapy and transplantation outlined. Research gaps flagged in B-cell-depleting therapy and early post-transplant immunogenicity.

4 parts: ciag114 · ciag115 · ciag116 · ciag117

Anki: not carded — confirmatory (vaccinate immunocompromised patients already standard)

Major studies & diagnostics

CIDDiagnostics · C. difficileHigh yield · ID

A Novel RNA Nucleic Acid Amplification Test More Accurately Distinguishes Active C. difficile Infection From Colonization

Can an RNA-based NAAT solve the sensitivity–specificity trade-off between DNA-NAAT and toxin EIA for CDI diagnosis?

What it isA novel multiplexed reverse-transcriptase PCR (RNA-NAAT) targeting C. diff–specific mRNA sequences. mRNA is expressed only by metabolically active bacteria and is rapidly hydrolyzed, distinguishing active infection from spore colonization. Key resultIn 239 clinical samples: RNA-NAAT achieved higher sensitivity than DNA-NAAT (100% vs 88.2% for organism detection) AND higher specificity for active infection than toxin EIA (99.5% vs 98.2%). Only 1 false positive (vs 7 for DNA-NAAT). Detection limit 30–50× lower than current methods. What this changesCould replace the 2-step algorithm with a single test that is both sensitive and specific for active CDI — resolving the fundamental trade-off that has driven the GDH→EIA→NAAT reflex workflows.

Clinical takeaway. Current CDI diagnostics force a choice: sensitive DNA-NAAT (over-detects colonization) or specific toxin EIA (misses active infections). The 2-step algorithm bridges the gap but adds complexity and turnaround time. This RNA-NAAT exploits the fundamental biology — mRNA = metabolically active organisms — to achieve both high sensitivity and high specificity in one test. Still single-center (n=239) and needs commercial development, but the principle is sound and the performance is striking.

Anki: carded — CID::Major_Study + Subject::Infectious_Disease

CIDMajor Article · C. difficileHigh yield · ID

A New Paradigm for C. difficile Infection: Atypical Presentations Correlating to Acute Gastrointestinal Dysmotility

How often does CDI present without diarrhea, and does this atypical presentation affect outcomes?

Key findingAmong 467 CDI episodes, 19.5% presented atypically — GI dysmotility symptoms (ileus, constipation, vomiting, delirium) persisted >24 h before any diarrhea. GI dysmotility (large and small bowel) was present in 32% at diagnosis. Small-bowel involvement in 16.3% of baseline imaging. OutcomeAtypical presentations had delayed treatment (median 4 vs 2 days, P<.001) and 90-day mortality 24.2% vs 9.6% (HR 2.62, 95% CI 1.51–4.57). Patients were older (74 vs 68), more comorbid, and more likely to have tachycardia and hypotension. What this changesChallenges the paradigm that CDI = diarrhea. The editorial (ciag464) notes that C. difficile may intoxicate the enteric nervous system, causing dysmotility before diarrhea. Supports extending CDI testing criteria beyond “3 unformed stools in 24 hours.”

Clinical takeaway. Nearly 1 in 5 CDI cases present with ileus, constipation, or vomiting before diarrhea develops. These patients are diagnosed later, treated later, and die at >2.5× the rate. The take-home: think CDI in the high-risk patient with unexplained ileus, abdominal distension, or delirium — don’t wait for diarrhea to test. Single-center retrospective, so the 19% is a signal, not a precision estimate — card the principle, not the number.

Anki: carded — CID::Major_Study + Subject::Infectious_Disease

CIDRCT · DiagnosticsHigh yield · ID

Clinical Impact of Rapid Molecular Diagnosis of Bloodstream Infections: A Randomized Controlled Trial

In patients with BSI, does BioFire BCID2 multiplex PCR from positive blood cultures (with stewardship) reduce time to effective therapy vs standard culture?

Population418 patients with positive blood cultures (208 SOC, 210 multiplex PCR), single center, Korea University Anam Hospital, June–October 2025. InterventionBioFire BCID2 multiplex PCR from positive blood cultures + antimicrobial stewardship vs SOC culture + stewardship. OutcomeMedian time to first effective antimicrobial modification: 23.2 vs 64.5 h (P<.001). Consistent across GN (30.5 vs 77.1 h), GP, regular vs off-hours, ICU vs non-ICU. Persistent BSI: 5.7% vs 11.5% (P=.038). No significant difference in 30-day mortality or LOS. What this changesAdds high-quality RCT evidence to the case for rapid multiplex PCR + stewardship in BSI management. Confirms the sepsis position paper’s recommendation for multiplex NAAT on positive blood cultures. Underpowered for mortality.

Anki: not carded — confirmatory of existing practice at most centers

Notable

CIDMajor Article · IE DiagnosisNotable · ID

Should Valve Leaflet Thickening Be Considered a Characteristic Lesion of Infective Endocarditis?

Does including valve leaflet thickening as an imaging criterion (per 2023 ESC, but not Duke-ISCVID) change IE diagnosis rates?

Key findingAmong 3,747 episodes of suspected IE, valve leaflet thickening was found in 8%. Of 193 IE episodes with thickening, 32% had no other characteristic intracardiac lesion. When thickening was excluded from imaging criteria, 50% still met a major imaging criterion — but the remainder would be reclassified. Editorial (ciag528) cautions that isolated leaflet thickening is inadequate as a standalone IE criterion given its low specificity.

Anki: not carded — single-center retrospective, evolving diagnostic criteria

CIDMajor Article · IE · TransplantNotable · ID

Infective Endocarditis in Solid Organ and Haematopoietic Stem Cell Transplant Recipients (E-IPA Study)

How does IE differ in SOT/HSCT recipients vs the general population?

Key findingLarge multicenter propensity-score-matched retrospective cohort (E-IPA study) characterizing IE microbiology, presentation, and outcomes in transplant recipients. Editorial (ciag510) contextualizes the findings for transplant ID practice.

Anki: not carded — observational, multicenter but retrospective

CIDMajor Article · C. aurisNotable · ID

Containment of a Candidozyma auris Outbreak Using Comprehensive Screening and Surveillance

Can hospital-wide PCR-based C. auris screening with IP&C interventions contain an acute care outbreak?

Key findingHarborview Medical Center 6-month outbreak. Screening transitioned from chromogenic culture → low-throughput PCR → house-wide high-throughput PCR via admission order sets. Comprehensive IP&C interventions including EHR contact tracing and Contact Precautions. Practical model for US acute care hospitals facing C. auris introduction.

Anki: not carded — single-center outbreak report

Also new this month

HCV Treatment With Glecaprevir-Pibrentasvir During Pregnancy (Brief Report) — First real-world data on GLE/PIB in pregnancy (n=14). All 10 who completed treatment achieved virologic response by delivery, with no maternal or neonatal safety signals. Fills a gap in IDSA/AASLD guidance endorsing antenatal DAA treatment.
Emergent Sulbactam-Durlobactam Non-Susceptibility in A. baumannii (Correspondence) — PBP3 A515V substitution + AdeFGH efflux pump overexpression as a mechanism for emergent SUL-DUR MIC increase (1/4 → 8/4 mg/L). Resistance surveillance signal for the newest CRAB agent.
Macrolide Resistance in M. genitalium in MSM in Milan (Correspondence) — 76% macrolide resistance (23S rRNA mutations) in 62 consecutive Mgen samples from MSM. Supports resistance-guided therapy and, when genotyping unavailable, empiric moxifloxacin in high-resistance settings (cf. FARTHEST RCT).
Difficult Diagnosis: C. difficile Without Diarrhea (Editorial Commentary) — Companion to the atypical CDI presentation article (ciag463). Discusses enteric nervous system intoxication as a mechanism for CDI-associated dysmotility.

Anki cards generated this pull

2 cards minted (hard ceiling 25; gate = ID-fellow level, 4 gates applied). 6 IDSA guidelines featured but not carded (reference documents — consult per case). 1 RCT featured but not carded (confirmatory of existing practice). 4 notable items summarized only. All cards tagged CID::Major_Study + Subject::Infectious_Disease; see 2026-08-31_CID-anki-cards.tsv.

Original paraphrase — all figures from the archived full text. Links go to the publisher (DOI). For personal study only; not for redistribution.