Alcaligens (1)

Alcaligens presentation

1. Alcaligenes By- Sanju Sah St. Xavier’s college, Maitighar , Kathmandu Department of Microbiology

2. CLASSIFICATION Kingdom: Bacteria Phylum: Proteobacteria Class: Betaproteobacteria Order: Burkholderiales Family: Alcaligenaceae Genus: Alcaligenes Species: faecalis

3. INTRODUCTION Alcaligenes is a genus of Gram-negative, rod-shaped bacteria. They are obligately aerobic, but some can undergo anaerobic respiration if nitrate is present. The species are motile with peritrichous flagella and rarely non motile. They have a distinct cell wall. It is a genus of non fermenting bacteria. Strains of Alcaligenes (such as A . faecalis ) are found mostly in the intestinal tracts of vertebrates, decaying materials, dairy products, water, and soil; they can be isolated from human respiratory and gastrointestinal tracts and wounds in hospitalized patients with compromised immune systems.

4. It is a pathogenic, opportunistic bacteria. Samples from blood, urine, feces, discharge from ears, spinal fluid, and wounds have produced this type of bacteria. Alcaligenes species have been increasingly recovered over the past decade from patients with cystic fibrosis (CF). Some species of  Alcaligenes  are potential causes of chronic pulmonary disease in patients with cystic fibrosis.  Alcaligenes  generate energy in a number of ways, including arsenite oxidation.

5. A. faecalis It was isolated in 1896 by Petruschky from stale beer. It is motile, flagellated, slender, slightly curved, not spore-forming, slowly growing, non fermenting, capsule forming, gram-negative aerobe of the family Alcaligenaceae . Most commonly found in the alimentary tract as a harmless saprophyte in 5% – 19% of the normal population. Causes sepsis, meningitis, peritonitis, enteric fever, appendicitis, cystitis, chronic suppurative otitis media, abscesses, arthritis, pneumonitis, and endocarditis. It has been associated with fatal outcomes because these organisms are resistant to commonly used antibiotics.

6. Habitat (Reservoir) Mode of transmission Virulence factor Spectrum of disease and infection Alcaligenes faecalis Environment, soil, water, moist hospital grounds, skin Exposure to medical devices and solutions Unknown Usually involves immunocompromised patients. Involves blood, urine, respiratory tract Alcaligenes piechaudii Environment Rarely found in humans Unknown Rarely causes human infection

7. Biochemical Tests of Alcaligenes faecalis subsp. faecalis

8. PATHOLOGY OF A. faecalis Many infections caused by the microbe are a result of contamination of medical devices. Kaliaperumal   et al.  (2006) have shown that  A. faecalis  may be a causative agent in postoperative endophthalmitis in the human eye. Patients on endophthalmitis may experience swelling of the eyelid, redness, and permanent loss of vision. Kahveci   et al.  (2011) found that catheters contaminated with  A. faecalis  may be associated with development of peritonitis in peritoneal dialysis patients. Symptoms of peritonitis include vomiting, passing little or no stool, sore and bloated abdomen, and fever .

9. The microbe has been found to cause urinary tract infections in humans. A. faecalis  has also been found in corneal ulcers, feces, blood, and other bodily fluids. In addition to infecting humans,  A. faecalis  is a pathogen of domesticated chickens, domesticated turkeys, and other birds. Although  A. faecalis  has been isolated from human and non-human hosts, the pathogenic mechanism of the microbe is largely unknown.

10. LAB DIAGNOSIS Specimen : Blood , urine, feces, discharge from ears, spinal fluid, and wounds Gram staining : Gram-negative, rod-shaped, flagellated, slender, slightly curved, non spore-forming, capsule forming Culture -Blood Agar : Feather edged colonies usually surrounded by zone of green discoloration, produces highly characteristic fruity odor resembling apples or strawberries -Mac Conkey Agar : Non lactose fermenter Biochemical tests

11. TREATMENT Currently, carbapenems , antipseudomonal penicillins , and trimethoprim/ sul - famethoxazole are considered the agents of choice for the treatment of A.  faecalis infections

12. REFERENCES https://www.jstage.jst.go.jp/article/yoken/68/2/68_JJID.2014.164/_ pdf Bailey and Scott (2007). Diagnostic Microbiology 12 th edition Elsevier pp 363-369 https:// microbewiki.kenyon.edu/index.php/Alcaligenes_faecalis_NEUF2011 https://www.sciencedirect.com/topics/biochemistry-genetics-and-molecular-biology/alcaligenes-faecalis

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