From the Guidelines
The Enterobacteriaceae family is a large and diverse group of gram-negative, rod-shaped bacteria that play a significant role in clinical microbiology and human disease, characterized by their ability to ferment glucose, reduce nitrates to nitrites, and test negative for oxidase, as noted in a study published in the World Journal of Emergency Surgery in 2017 1. The Enterobacteriaceae family includes important pathogens such as Escherichia coli, Klebsiella, Salmonella, Shigella, Proteus, Enterobacter, Serratia, and Yersinia, which are widely distributed in nature and can be found in soil, water, plants, and the intestinal tracts of humans and animals. Some key characteristics of Enterobacteriaceae include:
- Facultative anaerobes
- Ability to ferment glucose
- Reduction of nitrates to nitrites
- Negative test for oxidase
- Outer membrane containing lipopolysaccharide (LPS), which contributes to their pathogenicity through endotoxin activity
- Peritrichous flagella for motility, though some genera are non-motile These organisms cause a wide spectrum of infections, including:
- Urinary tract infections
- Pneumonia
- Septicemia
- Meningitis
- Gastrointestinal diseases Many members of this family have developed antimicrobial resistance, particularly through production of extended-spectrum beta-lactamases (ESBLs) and carbapenemases, making infections increasingly difficult to treat, as highlighted in the 2017 WSES guidelines for management of intra-abdominal infections 1. Laboratory identification of Enterobacteriaceae relies on biochemical tests, growth characteristics on selective media, and molecular methods. Understanding the characteristics of Enterobacteriaceae is essential for proper diagnosis, treatment, and infection control measures in clinical settings, especially in the context of intra-abdominal infections, where empiric antibiotic therapy is critical for preventing unnecessary morbidity and mortality 1.
From the Research
General Characteristics of Family Enterobacteriaceae
- Enterobacteriaceae are a large family of Gram-negative, non-spore-forming bacteria 2
- They are commonly found as part of the natural flora of animals, including humans, but some members are associated with intestinal and extraintestinal diseases 2
Disease-Causing Members of Enterobacteriaceae
- Salmonella, Escherichia, Shigella, and Yersinia are notable members of this family that play important roles in human disease 2
- These bacteria can cause a range of diseases, and animal models have contributed to our understanding of their pathogenesis and host genetic determinants involved in susceptibility or resistance to infection 2
Antimicrobial Resistance in Enterobacteriaceae
- Enterobacteriaceae spp. isolated from hospitalized patients with urinary tract infections often exhibit resistance to commonly used antimicrobials 3, 4
- Extended-spectrum beta-lactamase (ESBL) production is a significant concern, with bla(CTX-M) genes commonly found in Escherichia coli and Klebsiella pneumoniae 3
- The incidence of ESBL-producing Enterobacteriaceae is increasing, and recent antibiotic therapy and preterm gestational history are associated with an increased risk of ESBL acquisition 4