Author: Rebecca Buxton
Citation: Rebecca Buxton. 2007. Examination of gram stains of intraabdominal infections.
Publication Date: February 2007
Gram-positive Cocci (Enlarged view)
Slide 1. Abdominal abscess
This aspirate of an abscess contains many neutrophils and a few gram-positive cocci in pairs and short chains, some of which form circles. The many pleomorphic, faintly-stained gram-negative coccobacilli look like Bacteroides species. The culture grew Enterococcus faecalis, Bacteroides fragilis, and Pseudomonas aeruginosa. Some of the thin gram-negative bacilli could be Pseudomonas, but certain identification is difficult.
Gram-negative Bacilli (Enlarged view)
Slide 2. Peritonitis
This aspirate of peritoneal fluid contains a few neutrophils and numerous faintly-stained, thin, short, and sometimes coccoid, gram-negative bacilli. Their structure and source strongly suggest that the organisms are anaerobic. However, they could also be other bacteria, such as Eikenella or other fastidious bacilli. Only Bacteroides fragilis grew on this culture.
Slide 4: Gram-negative Bacilli (Labeled view)
Gram-positive Cocci & Gram-negative Rods (Enlarged view)
Slide 3. Peritonitis
This aspirate of peritoneal fluid contains a few neutrophils; several gram-positive cocci singly, in pairs, and in chains; and many gram-negative bacteria of various forms. They include long, slender bacilli with pointed ends, shorter rods, and cocci. Mixed anaerobic flora grew on the culture. Anaerobic and microaerophilic streptococci tend to be smaller than facultative streptococci, but the distinction is often difficult to make on Gram stains.
Gram-negative Coccobacilli & Gram-positive Bacilli (Enlarged view)
Slide 4. Peritonitis
This aspirate of peritoneal fluid contains a few neutrophils, a few gram-negative coccobacilli, and thick gram-positive bacilli that resemble Clostridium. Mixed anaerobic flora, including Clostridium species, grew on the culture.
Gram-negative Coccobacilli & Gram-positive Bacilli (Labeled view)
Gram-positive Cocci & Gram-negative Coccobacilli (Enlarged view)
Slide 5. Peritonitis
This slide of peritoneal fluid from a patient with a perforated colonic diverticulum demonstrates several neutrophils and bacteria of two major types: gram-positive cocci in chains and pleomorphic gram-negative coccobacilli. Cultures of fluid yielded a Peptostreptococcus species. These anaerobic bacteria are numerous in the fecal flora and are common in infections that complicate colonic perforation.
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