'Gram-negative anaerobes, straight, curved or spiral-shaped rods' refer to a group of bacteria that share certain characteristics. Here is a medical definition of these terms:

1. Gram-negative: These are a type of bacteria that do not retain crystal violet dye in the Gram staining procedure. Instead, they take up a counterstain such as safranin or fuchsin, which results in their pink coloration. This characteristic is due to the structure of their cell walls, which contain a thin peptidoglycan layer and an outer membrane containing lipopolysaccharides (LPS).
2. Anaerobes: These are bacteria that do not require oxygen for growth and may even be inhibited or killed by its presence. They can be further classified as obligate anaerobes, which cannot grow in the presence of oxygen, or facultative anaerobes, which can grow with or without oxygen.
3. Straight, curved, or spiral-shaped rods: These terms refer to the shape of the bacteria. Straight rods are also known as bacilli, while curved rods may be described as coccobacilli (slightly curved) or vibrios (comma-shaped). Spiral-shaped rods are called spirilla if they are rigid or spirochetes if they are flexible.

Examples of Gram-negative anaerobic, straight, curved, or spiral-shaped rods include species of Bacteroides, Prevotella, Porphyromonas, Fusobacterium, and Campylobacter. These bacteria are commonly found in the human mouth, gastrointestinal tract, and female genital tract, and can cause a variety of infections, including dental abscesses, periodontitis, intra-abdominal infections, and pelvic inflammatory disease.