Legacy AI grade · Sources dated 2026-06-09. Not expert reviewed. Coverage is limited to the listed sources. About the new summary workflow
Lactobacillus casei Shirota (LcS) for Icu Infection Prevention
Verdict: Published
Across 6 PubMed studies, the evidence for Lactobacillus casei Shirota (LcS) in Icu Infection Prevention grades Tier C — weak evidence.
C 🟠 C Weak Evidence Published
Why this grade7-layer evidence engine
LcS for ICU infection prevention has weak, outdated evidence. The Cochrane 2014 review (PMID 25344083) predates the PROSPECT 2021 mega-trial (PMID 34546300, n=2,653, L. rhamnosus GG, null).
The strain-exact LcS RCT (PMID 25920295) was non-significant for ventilator-associated pneumonia. L11 recommends needs_more_evidence while status is published — a material policy gap.
SCCM 2026 guidance cautions against probiotics in sepsis. Tier C reflects historical positive signals superseded by larger null trials.
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Scoring transparency
All scores computed by a 7-layer evidence engine — fully auditableRaw score 0.45
D
C
B
A
S
← counter-evidence / ineffectiveeffective / strong evidence →
Final grade
C · Published
Confidence
74%
Broadly consistent
Evidence level
E3
Cochrane 25344083 predates PROSPECT 2021 (34546300, n=2653, null); LcS RCT non-significant
▸View the full decision path (audit trail)
- compute_raw_score — 加權公式: L2×0.30 + L3×0.25 + L5×0.25 + L11×0.10 + L1×0.10 = 0.452
- tier_from_score — 依分數區間映射至 tier letter
- apply_hec_rules — 高品質 SR/MA 顯示 positive (1 篇 > 0 negative)
- tier_strict_requirement_check — Tier 條件達標，未降階
- detect_disputes — 偵測到 0 個 hard + 0 個 soft dispute
- decide_status — 依 tier + dispute 結果決定 status
PubMed studies (6)L2 · primary research & systematic reviews
Probiotics for preventing ventilator-associated pneumonia
Finding: Pooled probiotics reduced VAP (OR 0.70, 95% CI 0.52-0.95) but on low-quality evidence, with no clear effect on ICU mortality (OR 0.84, 95% CI 0.58-1.22); authors concluded evidence was insufficient to support efficacy/safety.
View on PubMed Effect of Probiotics on Incident Ventilator-Associated Pneumonia in Critically Ill Patients: A Randomized Clinical Trial (PROSPECT)
Finding: Lactobacillus rhamnosus GG showed no difference in VAP versus placebo (21.9% vs 21.3%; HR 1.03, 95% CI 0.87-1.22, P=.73), and authors concluded findings do not support probiotic use in critically ill patients.
View on PubMed Randomized controlled study of probiotics containing Lactobacillus casei (Shirota strain) for prevention of ventilator-associated pneumonia
Finding: LcS showed only a non-significant trend toward lower VAP (24% vs 29.3%, p=0.46; 22.64 vs 30.22 episodes/1,000 ventilator-days, p=0.37), with no effect on mortality or length of stay.
View on PubMed Efficacy of probiotics or synbiotics in critically ill patients: A systematic review and meta-analysis
Finding: Across 33 RCTs probiotics/synbiotics reduced VAP (RR 0.80, 95% CI 0.67-0.96, p=0.021) but had no effect on ICU mortality (RR 0.95, 95% CI 0.71-1.27) or in-hospital mortality.
View on PubMed Clinical Benefits From Administering Probiotics to Mechanical Ventilated Patients in Intensive Care Unit: A PRISMA-Guided Meta-Analysis
Finding: Across 15 RCTs probiotics reduced VAP (OR 0.58, 95% CI 0.41-0.81, p=0.002) and bacterial colonization, but with no effect on ICU mortality (OR 0.91, 95% CI 0.80-1.05) and noted heterogeneity and potential publication bias.
View on PubMed Prevention of ventilator-associated pneumonia with probiotics: an overview of systematic reviews
Finding: This umbrella review of 13 systematic reviews found probiotics may reduce VAP incidence, but rated most outcomes low/very-low quality (only ~36% moderate) and cautioned against recommending probiotics owing to poor evidence quality.
View on PubMed Regulatory & authoritative positionsL4/L5 · FDA / EMA / NIH ODS / Cochrane / Mayo …
L4a US FDA
Supportive
GRN No. 429 — Lactobacillus casei strain Shirota. Intended Use: As an ingredient in fermented dairy products at a maximum level of 4x10^8 colony forming units per milliliter. FDA Response: has no questions. Notifier: Yakult Honsha Co., Ltd. (Tokyo, Japan). Filed April 10, 2012; closed December 10, 2012. source↗
L4b EU EFSA
Against
The Panel concluded that a cause and effect relationship has not been established between the consumption of Lactobacillus casei Shirota and maintenance of the upper respiratory tract defence against pathogens by maintaining immune defences. The Panel considered that there was no human study demonstrating an effect of Lactobacillus casei Shirota consumption on upper respiratory tract infections… source↗
L4c UK NHS
Cautious
Probiotics are generally classed as food rather than medicine, which means they don't go through the rigorous testing medicines do. ... There's some evidence that probiotics may be helpful in some cases, such as helping to ease some symptoms of irritable bowel syndrome (IBS). ... If you have an existing health condition or a weakened immune system, you should talk to a doctor before taking any … source↗
L4d TW TFDA / 衛福部
Supportive
養樂多活菌發酵乳 衛署健食字第A00032號 胃腸功能改善；養樂多300LIGHT活菌發酵乳 衛署健食字第A00128號 免疫調節、輔助調整過敏體質、胃腸功能改善；養樂多300活菌發酵乳 衛署健食字第A00178號 胃腸功能改善 source↗
L4e WHO
Neutral
Probiotics are live microorganisms which when administered in adequate amounts confer a health benefit on the host. The 2002 FAO/WHO Working Group Guidelines for the Evaluation of Probiotics in Food require strain-level identification (genus, species, strain), in vitro testing (acid/bile tolerance), safety assessment (antibiotic resistance, metabolic activities, no transferable resistance), and… source↗
L5a NIH Office of Dietary Supplements
Neutral
With a total listing of over 500 scientific studies...it is fair to say that the L. casei strain Shirota is the most researched probiotic strain in the world. Classified as Lacticaseibacillus paracasei Shirota since April 2020. source↗
L5e Specialty Society (condition-mapped)
Against
For adults with sepsis or septic shock, we 'suggest against' using probiotics. source↗