Morgenella morganii: Introduction, Pathogenecity, Lab Diagnosis and Treatment

Morgenella infection lab diagnosis

Introduction of Morgenella

Morgenella morganii is a member of the family Enterobacteriaceae which was earlier called Proteus morganiiThis genus Morgenella has only one species, M. morganiiIt can be found in human and animal tissues and sewage, soil, and water.

Pathogenecity of Morgenella

It cause rarely urinary tract infections (UTI),hospital-acquired infections and it has also been reported as causing diarrhea in infants.

Laboratory Diagnosis  of Morgenella

Gram stain: Gram-negative bacilli

Culture: Non-lactose fermenting colonies on MacConkey agar. Blood agar is lacking swarming type growth i.e. having individual colonies.

Biochemical Reaction:

In triple sugar iron agar (TSI) test-

Red slant, yellow butt

No hydrogen sulfide (H2S) production

About gas formation- different strains  give different results

 Motility indole and urease (MIU) test –

Generally motile ( a few strains may be non-motile)

Indole test- positive

Urea hydrolyzation test-Positive

Citrate utilization test


Phenylalanine deaminase (PDA) also called phenyl pyruvic acid (PPA) test


Treatment of Morgenella

M. morganii strains are intrinsic resistant to penicillin, ampicillin, ampicillin, and combination of sulbactam, oxacillin, first-generation and second-generation cephalosporins, erythromycin, tigecycline, colistin, and polymyxin B and susceptible to piperacillin, ticarcillin, mezlocillin, third-generation, and fourth-generation cephalosporins, carbapenems, aztreonam, fluoroquinolones, aminoglycosides, and chloramphenicol. Even the widespread use of third-generation cephalosporins has been associated with the emergence of highly resistant M. morganii.

Case report

A 47 years old female patient having signs and symptoms of urinary tract infection (UTI) so the clinician requested a urine routine examination. The report was suggestive for UTI having plenty of pus cells and few red blood cells and thus clinician finally ordered urine culture and sensitivity.


Morgenella morganii isolated (>105CFU/ml)

Sensitivity –








Ceftriazone -Sensitive

Meropenem- Sensitive


The patient was treated with ofloxacin and finally, she was cured of UTI.


Supportive features of lab diagnosis as shown above figure.

Further Readings

  1. Topley and Wilson’s microbiology and microbial infection- Bacteriology-2-10th Edition
  2.  Manual of Clinical   Microbiology-Patrick R. Murray -8th Edition
  3. Bailey and Scott’s  Diagnostic Microbiology-13th   Edition
  4. Mackie & Mc Cartney  Practical Medical Microbiology- 14th  Edition
  5. Diagnostic Microbiology-Connie R. Mahon & George Manuselis
  6. District Laboratory Practice in  Tropical Countries-  Part-2-   Monica Cheesebrogh-   2nd Edition  Update
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