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Organisms Expected From Common Body Sites/Specimens, continued

Body Site/Specimen Organism(s) Commonly Expected Comments
  • Neisseria gonorrhoeae: Intracellular gram-negative diplococci (GNDC)
  • Yeast: Large ovals with budding forms and hyphae
  • Gardnerella species: Small, gram-variable or gram-negative coccobacilli
  • Enterics such as E. coli and Pseudomonas: Gram-negative rods (GNRs)
  • Streptococcus species: Gram-positive cocci (GPC) in pairs and chains
  • Staphylococcus species: GPC in clusters and tetrads
  • Lactobacillus species: Gram-variable or gram-positive, pleomorphic rods or coccobacilli
  • Normal genital flora includes GPC, GPRs, and GNRs.
  • Normal urethral flora includes corynebacteria, COAG-negative staphylococci, and anaerobes.
  • In women of reproductive age, normal flora (NF) of the genital tract includes Enterobacteriaceae, anaerobes, staphylococci, and streptococci.
  • Lactobacilli are predominant in healthy vaginal secretions.
  • In prepubescent and postmenopausal women, NF of the genital tract includes primarily staphylococci and corynebacteria.
  • Intracellular GNDC are diagnostic for gonorrhea in urethral discharge and presumptive in vaginal discharge. Saprophytic GNDC exist in the female genital tract.
  • Streptococcus agalactiae (group B beta-hemolytic streptococci) may be carried by many women and transmitted to the neonate.
  • Staphylococcus: GPC in clusters and tetrads
  • Streptococcus: GPC in pairs and chains
  • Neisseria: GNDC
  • Haemophilus: Pale pink gram-negative coccobacilli (GNCB)
  • Enteric GNRs, such as E. coli
  • Generally, only 1 morphotype is expected in sterile body sites.
  • S. aureus is the most common pathogen recovered in septic arthritis.
  • N. gonorrhoeae is the most frequently isolated organism in adults under the age of 30 with septic arthritis.
  • H. influenzae is the most common pathogen in children less than two with infectious arthritis, followed by S. aureus.
  • Common pathogens also include group A and B streptococci, pneumococci, and viridans streptococci, as well as anaerobes such as Bacteroides and Fusobacterium.