252.1 🎓 醫孞生版

252.1.0.1 📌 䞀頁重點

252.1.0.1.1 Candida auris
252.1.0.1.1.1 Background
  • First identified 2009 Japan (ear discharge); spread rapidly globally
  • WHO Critical Priority Pathogen 2022
  • CDC Urgent Threat 2019
  • Genome studies: 4 distinct clades (South Asia, S America, Africa, E Asia) — independent emergence
252.1.0.1.1.2 Microbiology
  • Multi-drug resistant (60-90% fluconazole-R; some echinocandin-R; some pan-resistant)
  • Difficult to identify by conventional methods (often misidentified as C. haemulonii or C. famata)
  • MALDI-TOF with updated database identifies correctly
  • PCR developed for surveillance
252.1.0.1.1.3 Risk + Settings
  • Hospital / LTC outbreaks
  • Catheter + ventilator + immunocompromise
  • Healthcare worker hand colonization
  • Prolonged contact precautions failure
  • Environmental persistence (months on surfaces)
  • 2024 + ongoing global increase
252.1.0.1.1.4 Clinical
  • Bloodstream + line infections
  • UTI
  • Wound + soft tissue
  • Mortality high (30-60%)
252.1.0.1.1.5 Treatment
  • Echinocandin first-line (caspofungin, micafungin, anidulafungin)
  • Liposomal AmB alternative
  • Combination (echinocandin + AmB) for severe / refractory
  • AST essential (resistance variable)
  • Newer agents (ibrexafungerp, fosmanogepix, olorofim) under investigation
252.1.0.1.1.6 Infection Control
  • Contact precautions (gloves + gowns)
  • Cohorting infected patients
  • Environmental cleaning (chlorhexidine, sporicidal — bleach 1:10 or specific products)
  • Surveillance cultures
  • Hand hygiene meticulously
  • 通報 to public health
252.1.0.1.2 Fusarium
252.1.0.1.2.1 Background
  • Filamentous mold; multiple species (F. oxysporum, F. solani, F. moniliforme)
  • Plant pathogens + soil + decaying material
  • Drinking water contamination (hospital water systems)
252.1.0.1.2.2 Risk
  • Severe neutropenia (prolonged > 10-14 days)
  • HSCT + leukemia
  • Burns
  • IV catheters
  • Severe trauma
252.1.0.1.2.3 Clinical
  • Disseminated infection common in neutropenic
  • Fungemia + skin lesions (multiple painful nodules + ulcers + ecthyma gangrenosum-like)
  • Pulmonary infiltrates + sinusitis
  • Endophthalmitis
  • Mortality 50-80%
252.1.0.1.2.4 Diagnosis
  • Blood cultures POSITIVE (unique among molds; Fusarium often grows in blood)
  • Skin biopsy + culture
  • Galactomannan: variable (sometimes positive)
  • β-D-glucan elevated
  • PCR
252.1.0.1.2.5 Treatment
  • Voriconazole + liposomal AmB combination often
  • Posaconazole alternative
  • Isavuconazole alternative
  • Mortality high
  • Immune recovery essential
252.1.0.1.3 Scedosporium / Lomentospora
252.1.0.1.3.1 Species
  • Scedosporium apiospermum (Pseudallescheria boydii teleomorph)
  • Scedosporium prolificans (now Lomentospora prolificans — separate genus)
  • Worldwide soil + sewage + ponds
252.1.0.1.3.2 Risk
  • Drowning + near-drowning (Pseudallescheria pneumonia after aspiration)
  • CF (colonization + infection)
  • Immunocompromise + neutropenia + transplant
  • Trauma + IV exposure
252.1.0.1.3.3 Clinical
  • Pulmonary infection
  • Sinusitis
  • Cutaneous + soft tissue
  • CNS abscess
  • Disseminated in severe immunocompromise
252.1.0.1.3.4 Treatment
  • Voriconazole (Scedosporium apiospermum responsive)
  • Lomentospora prolificans: VERY DRUG RESISTANT — often combinations + new agents (olorofim Phase 3)
  • Surgery for localized
252.1.0.1.4 Trichosporon
252.1.0.1.4.1 Background
  • Yeast (T. asahii, T. inkin, T. ovoides)
  • Skin commensal + environmental
252.1.0.1.4.2 Clinical
  • White piedra (superficial; hair shafts)
  • Disseminated trichosporonosis (neutropenic; mimics candidiasis)
  • Bloodstream + multiple organ
  • Cross-reacts with cryptococcal antigen test
252.1.0.1.4.3 Treatment
  • Voriconazole preferred (echinocandins NOT active)
  • Posaconazole, isavuconazole, AmB alternatives
252.1.0.1.5 Dematiaceous (Black) Fungi
252.1.0.1.5.1 Background
  • “Phaeohyphomycosis” — disease caused by black molds
  • Pigmented hyphae in tissue
  • Multiple species: Cladophialophora, Bipolaris, Curvularia, Alternaria, Exophiala
252.1.0.1.5.2 Clinical
  • Cutaneous (most common): trauma inoculation; nodules + ulcers
  • Sinusitis (allergic + invasive)
  • CNS abscess (rare but severe)
  • Allergic bronchopulmonary fungal disease (different from ABPA but similar)
  • Disseminated in immunocompromise (rare)
252.1.0.1.5.3 Diagnosis
  • Histology: pigmented hyphae in tissue (Fontana-Masson stain enhances)
  • Culture (slow-growing black mold)
252.1.0.1.5.4 Treatment
  • Itraconazole + voriconazole + posaconazole for various species
  • Surgical excision for localized cutaneous
  • Long-term therapy often
252.1.0.1.6 Other Emerging Fungi
  • Saccharomyces cerevisiae: probiotic-related fungemia
  • Geotrichum candidum: opportunistic
  • Rhodotorula: line-related; AmB
  • Magnusiomyces capitatus (formerly Trichosporon capitatum)
  • Saprochaete: outbreaks in HSCT
252.1.0.1.7 Newer Antifungals for Emerging
  • Ibrexafungerp (Brexafemme, FDA 2021): oral triterpenoid; some activity against resistant Candida + emerging
  • Fosmanogepix (Phase 3): broad-spectrum including C. auris
  • Olorofim (Phase 3): orotomide; active against azole-resistant Aspergillus + Lomentospora + Scedosporium + Fusarium
  • Newer formulations: encochleated AmB (oral)