Changes in Aerobic Pharyngeal Flora Related to Antibiotic Use and the Emergence of Gram-negative Bacilli

Abstract

Pharyngeal flora were evaluated semi-quantitatively by counting and differentiating the colonies growing on blood agar plates into four major bacterial groups. In children they consisted mainly of alpha-streptococci, followed by smaller portions of Neisseria, and of gram-positive organisms other than alpha-streptococci. Gram-negative bacilli did not occur under normal conditions. Oral ampicillin in a daily dose of 50 mg/kg caused suppression of the alpha-streptococci, and promoted emergence of gram-negative bacilli. Oral cephalexin in the same dose caused changes in the same direction, but less extensively than ampicillin . Parenteral aminoglycoside antibiotics in usual dosage did not change the pharyngeal flora. Differential counting of the growth is a simple and useful tool to evaluate the ecology of pharyngeal flora. It serves to monitor overgrowth of resistant organisms in the respiratory tract.

Multiple aPDT sessions on periodontitis in rats treated with chemotherapy: histomorphometrical, immunohistochemical, immunological and microbiological analyses

“…Therapeutic approaches to the suppression of potential pathogens in the oral microflora with antibiotics to decrease the risk of infections in patients undergoing chemotherapy have been proposed. These approaches have sometimes been successful [26], but they can also promote increased bacterial resistance [27].…”

The time course and microbiology of surgical site infections after head and neck free flap surgery

“…However, head and neck cancer patients may be colonized by non-normal oral flora bacteria, 8 which may lead to early-onset SSIs. This flora may change during hospitalization, [9][10][11][12] and the new flora may contribute to late-onset SSIs.…”

Oral and intestinal microflora in 5‐fluorouracil treated rats, translocation to cervical and mesenteric lymph nodes and effects of probiotic bacteria

“…To decrease the risk for infections in patients on cancer chemotherapy, attempts have been made to suppress potential pathogens in the oral and intestinal microflora by antibiotics. This approach has sometimes been successful (36), but may instead cause overgrowth of antibiotic‐resistant bacteria, generally gram‐negatives (50). An alternate strategy has emerged in later years, to supply the gastrointestinal tract with probiotics, i.e.…”