Serratia ficaria: Introduction, Morphology, Pathogenicity, Lab Diagnosis, Treatment,Prevention, and Keynotes


Serratia ficaria is a bacterial species that belongs to the genus Serratia. It is a Gram-negative, rod-shaped bacterium that is commonly found in various environmental niches, including soil, water, and plants. Serratia ficaria is known for its ability to produce a distinctive red pigment called prodigiosin, which gives it a characteristic reddish appearance.

One notable characteristic of Serratia ficaria is its facultative anaerobic nature, meaning it can grow in both the presence and absence of oxygen. This adaptability allows it to thrive in a wide range of environments and contribute to its ecological versatility.

It is considered an opportunistic pathogen, meaning it can cause infections in humans, particularly in individuals with compromised immune systems or underlying medical conditions. It has been associated with various infections, including urinary tract infections, wound infections, and respiratory tract infections.

In addition to its pathogenic potential, S. ficaria has attracted attention in the field of biotechnology and research due to its ability to produce a variety of secondary metabolites and enzymes. These include proteases, lipases, and antimicrobial compounds, which have potential applications in various industries such as pharmaceuticals and bioremediation.


The morphology of Serratia ficaria is characterized by its cellular shape, arrangement, and other structural features. Here is an overview of the morphology of S. ficaria:

Cell Shape: Serratia ficaria is a Gram-negative bacterium that typically appears as straight or slightly curved rods under a microscope. The cells are typically 0.5 to 1.0 micrometers in diameter and 1.5 to 3.0 micrometers in length.

Cell Arrangement: Serratia ficaria cells can occur singly or in pairs, forming short chains or small clusters. They are not usually found in long filamentous arrangements.

Motility: It is typically motile, possessing peritrichous flagella that allow it to move in liquid environments. The motility of S. ficaria enables it to actively explore and colonize various habitats.

Capsule: Some strains of Serratia ficaria may produce a slimy capsule surrounding the bacterial cells. The capsule can play a role in protecting the bacterium from host immune responses and environmental stressors.

Colonial Appearance: When grown on solid media, Serratia ficaria colonies exhibit diverse appearances. They can range from smooth, opaque, and circular colonies to rough and irregular colonies. The color of the colonies can vary, but they often have a reddish appearance due to the production of the pigment prodigiosin.

Pigmentation: Serratia ficaria is known for its ability to produce prodigiosin, a red pigment. The pigment is often visible in the agar medium where the bacterium is growing, giving it a distinctive reddish coloration.


Serratia ficaria is an enterobacterium involved in the fig tree ecosystem, has been isolated from human clinical samples in rare instances, and its role as a pathogen is unclear. However it has been found in  patient with septicemia and  biliary infections.

Lab Diagnosis

The laboratory diagnosis of Serratia ficaria typically involves a combination of microbiological techniques. Here are the common methods used for the identification and diagnosis of Serratia ficaria :

  1. Gram Staining: A Gram stain can provide initial information about the bacterial morphology and Gram reaction of the isolate. S. ficaria  will appear as Gram-negative rods.
  2. Culture and Isolation: S. ficaria  can be cultured from clinical specimens, such as urine, sputum, wound swabs, or blood. Specimens are streaked onto appropriate culture media, such as MacConkey agar or blood agar, and incubated at a suitable temperature (typically 35-37°C) for 24-48 hours. Serratia ficaria colonies may appear as smooth, round, and slightly raised colonies with potential red or yellow or orange pigmentation.
  3. Biochemical Tests: Various biochemical tests can be performed to further identify S. fonticola. These may include testing for the presence of catalase (positive), oxidase (negative), and the ability to ferment sugar like glucose and  but lactose. Additionally,
  4. API Systems: The API 20E system or similar commercially available identification systems may be used to confirm the identification of S.  ficaria . These systems utilize a panel of biochemical tests to identify the bacterial species based on specific reactions.
  5. Molecular Methods: Polymerase chain reaction (PCR) assays or other molecular techniques can be employed to detect and identify Serratia ficaria more accurately. These methods target specific genes or sequences unique to S.  ficaria for definitive identification.
  6. Antibiotic Susceptibility Testing: Determining the antibiotic susceptibility pattern of the isolated Serratia fonticola strain is crucial for guiding appropriate treatment. The Kirby-Bauer disk diffusion method or automated systems, such as the Vitek or MicroScan systems, can be used to test the susceptibility of the isolate to various antibiotics.


  1. Antibiotics: Serratia species are often susceptible to a range of antibiotics, including fluoroquinolones, aminoglycosides, cephalosporins, and carbapenems. The choice of antibiotic and its specific dosage will depend on the susceptibility testing of the isolated strain.
  2. Combination Therapy: In some cases, combination therapy may be recommended, particularly for severe or complicated infections. This involves using two or more antibiotics with different mechanisms of action to enhance the effectiveness of treatment.
  3. Duration of Treatment: The duration of antibiotic therapy will vary depending on the site and severity of the infection. In general, treatment can last anywhere from a few days to several weeks.
  4. Supportive Care: In addition to antibiotic treatment, supportive care measures may be necessary to manage symptoms and promote healing. This may include wound care, pain management, and adequate hydration.
Antimicrobial Susceptibility Testing (AST) of Serratia ficaria
Antimicrobial Susceptibility Testing (AST) of Serratia ficaria


  1. Good Hand Hygiene: Regularly washing your hands with soap and water for at least 20 seconds, especially before eating, after using the restroom, and after touching surfaces in public areas, can help prevent the spread of bacteria.
  2. Proper Food Handling: Practice safe food handling and preparation techniques, including cooking food thoroughly, storing it at appropriate temperatures, and avoiding cross-contamination between raw and cooked foods.
  3. Safe Water Practices: Ensure the safety of drinking water by using clean and treated water sources. If you are unsure about the safety of the water, consider boiling it or using appropriate water purification methods.
  4. Infection Control in Healthcare Settings: Healthcare facilities should follow strict infection control measures, including proper hand hygiene, sterilization of medical equipment, and appropriate use of personal protective equipment, to prevent the transmission of bacteria between patients.
  5. Immunization: Stay up to date with recommended vaccinations, as some bacterial infections can be prevented through immunization.
  6. Proper Wound Care: Clean and cover wounds properly to prevent bacterial contamination and promote healing. Seek medical attention for any signs of infection, such as redness, swelling, or discharge.
  7. Avoid Close Contact with Sick Individuals: If someone is sick with a bacterial infection, try to maintain a safe distance and avoid close contact to minimize the risk of transmission.
  8. Environmental Hygiene: Keep your environment clean by regularly disinfecting frequently touched surfaces and objects.


  1. Genus Serratia: Serratia is a genus of Gram-negative bacteria belonging to the family Enterobacteriaceae. It includes several recognized species, such as Serratia marcescens, Serratia liquefaciens, and Serratia rubidaea.
  2. Natural Environment: Serratia species are commonly found in soil, water, plants, and the gastrointestinal tracts of animals, including humans.
  3. Opportunistic Pathogens: Serratia species are considered opportunistic pathogens, meaning they primarily cause infections in individuals with weakened immune systems or underlying medical conditions. They can cause a range of infections, including urinary tract infections, respiratory tract infections, bloodstream infections, wound infections, and pneumonia.
  4. Antibiotic Resistance: Some Serratia species have developed resistance to multiple antibiotics, posing challenges in the treatment of infections caused by these bacteria. It is important to perform antibiotic susceptibility testing to guide appropriate antibiotic therapy.
  5. Nosocomial Infections: Serratia species have been associated with hospital-acquired infections, particularly in intensive care units and other healthcare settings. Strict infection control measures and proper hand hygiene are essential to prevent the spread of these bacteria.
  6. Prodigiosin Pigment: Many Serratia species, such as Serratia marcescens, are known for producing a red pigment called prodigiosin. This pigment gives the colonies a distinctive reddish coloration.

Further Readings

  1. Mahlen, S. D. (2011). Serratia infections: from military experiments to current practice. Clinical Microbiology Reviews, 24(4), 755-791.
  2. Grimont, P. A. D., & Grimont, F. (2006). Genus XIII. Serratia. In The Prokaryotes: Volume 6: Proteobacteria: Gamma Subclass (3rd ed., pp. 219-244). Springer.
  3. Castro, M. E., Molina-Quiroz, R. C., Urrutia, I. M., Pizarro-Guajardo, M., Lobos-Ruiz, P., García-Pérez, L., González-Rocha, G., & Arenas-Salinas, M. (2019). Serratia spp.: An emerging pathogen in hospital-associated infections. In Microbial pathogens and strategies for combating them: Science, technology and education (Vol. 1, pp. 349-357). Formatex Research Center.

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