Proteus hauseri is a Gram-negative, facultatively anaerobic bacillus in the Enterobacteriaceae family. It is closely related to other Proteus species and commonly found in soil, water, and the human gastrointestinal tract. Though less prevalent than P. mirabilis P. hauseri can cause opportunistic infections—especially in hospitalized or immunocompromised patients.
Fig. Proteus hauseri colony morphology on MacConkey agar of urine culture Cellular: Straight to slightly curved rods, 0.4–0.8 µm × 1.0–3.0 µm Motility: Highly motile via peritrichous flagella; exhibits “swarming” on solid media Colony Appearance on MacConkey : Pale, non-lactose-fermenting colonies (colorless) Other Media: On nutrient agar, forms concentric rings due to periodic swarming waves Adhesion & Invasion: Fimbriae and adhesins mediate attachment to urinary epithelium Enzymatic Factors: Urease production elevates urinary pH, promoting stone formation Infection Spectrum: Urinary tract infections (UTI) : Especially catheterized patientsWound infections: Including surgical sites and decubitus ulcers Bacteremia & Sepsis : In neonates or immunocompromised hosts Rarely: Respiratory or intra-abdominal infections Specimen Culture: Inoculate urine, wound swab, or blood onto MacConkey and blood agar ; incubate at 35–37 °C. Colony & Swarming: Observe non-lactose-fermenting colonies with swarming on non-inhibitory media. Biochemical Tests Fig. Proteus hauseri in a wet mount of culture Urease positive (rapid)Indole variable (distinguishes from P. mirabilis ) Phenylalanine deaminase positive TSI: K/K with H₂S production Automated ID: MALDI-TOF MS or biochemical panels (e.g., API 20E ) confirm species. Antimicrobial Susceptibility: CLSI disk diffusion or automated broth microdilution, with special attention to AmpC-mediated β-lactam resistance . First-Line: Trimethoprim-sulfamethoxazole Fluoroquinolones (e.g., ciprofloxacin) β-Lactams: Carbapenems or β-lactam/β-lactamase-inhibitor combinations guided by susceptibility Avoid: Ampicillin or first-generation cephalosporins if AmpC β-lactamase is present Supportive Care: Hydration, catheter removal, or change in UTIs Aseptic Technique: Especially during catheter insertion and wound care Catheter Management: Remove or replace indwelling catheters promptly Environmental Controls: Regular disinfection of hospital surfaces and equipment Antibiotic Stewardship: Limit broad-spectrum cephalosporins to reduce AmpC induction Swarming Motility: Unique diagnostic clue on non-inhibitory media Urease Activity: A Major virulence factor in UTIs and stone formation AmpC β-lactamase : Watch for inducible resistance to many β-lactamsOpportunistic Pathogen: Primarily affects hospitalized or immunocompromised patients, requiring vigilant infection control https://pmc.ncbi.nlm.nih.gov/articles/PMC88947/ https://www.sciencedirect.com/topics/pharmacology-toxicology-and-pharmaceutical-science/proteus http://www.antimicrobe.org/b226.asp https://www.culturecollections.org.uk/nop/product/proteus-hauseri https://www.canada.ca/en/public-health/services/laboratory-biosafety-biosecurity/pathogen-safety-data-sheets-risk-assessment/proteus.html https://medtigo.com/pathogen/proteus-hauseri/ https://www.atcc.org/products/13315 https://en.wikipedia.org/wiki/Proteus_hauseri https://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&id=183417 https://emedicine.medscape.com/article/226434-overview
