Experimental otitis media in gerbils and chinchillas with Streptococcus pneumoniae, Haemophilus influenzae, and other aerobic and anaerobic bacteria

Abstract

To ascertain the usefulness of Mongolian gerbils as an inbred model for otitis media, 52 Mongolian gerbils (Meriones unguiculatus, strain MON/Tum) were compared with 26 chinchillas (Chinchilla laniger) for susceptibility to Streptococcus pneumoniae type 3, Haemophilus influenzae type b, and a polymicrobic culture including anaerobes (Streptococcus intermedius, Propionibacterium acnes, Staphylococcus epidermidis, and Corynebacterium sp.). Organisms were inoculated percutaneously into the superior chamber of the middle ear bulla. The gerbils and chinchillas shared similar susceptibilities and responses to the inoculated organisms as determined by X-ray, otoscopic, histopathological, and microbiological determinations at 5 to 7 days. Koch's postulate studies proved the role of S. pneumoniae and H. influenzae in the pathology found in both animal models. The animals were also susceptible to the polymicrobic culture, although the relative virulence of the individual members of this mixture was low, suggesting that these species potentiated as a polymicrobic mixture. The Corynebacterium sp. appeared to elicit the greatest histopathological response in chronic (8-week) studies in gerbils. The gerbils were found to be useful as an alternative animal model for the study of otitis media of bacterial etiology. bils to otitis media when inoculated with Streptococcus pneumoniae type 3, H. influenzae type 802 on July 16, 2020 by guest

Otomicroscopic findings and systemic interleukin‐6 levels in relation to etiologic agent during experimental acute otitis media

“…Gram‐positive bacteria induced a more aggressive clinical picture with bulging tympanic membranes and more dilated vessels than the gram‐negative bacteria, which produced more often retracted tympanic membranes with relatively thin vessels in the rat model. These findings are similar to those reported from other animal models and humans (12, 13, 15). A red tympanic membrane is an established criterion for AOM.…”

“…The diagnosis of AOM rests today on the visualization of the tympanic membrane, its pathology, and the experience and skill of the examining physician. Studies in an established rat otitis model have indicated that different pathogens yield different otomicroscopic findings and host responses (11–15). The interleukin(IL)‐6 gene is rapidly expressed in the rat middle ear mucosa during AOM, and, in contrast to other cytokines, the rapidity is independent of etiology (16).…”

In Vivo Efficacies of Amoxicillin and Cefuroxime against Penicillin-Resistant Streptococcus pneumoniae in a Gerbil Model of Acute Otitis Media

“…It is also common that the cefuroxime MICs for such strains are higher than those of amoxicillin (12). In addition, this strain was able to induce AOM in gerbils, as described by other investigators (3,10).…”

“…AOM induced in gerbils is a well-established model for studying AOM as well as for comparing the efficacies of different antimicrobial regimens (3,10).…”

Detoxified lipooligosaccharide from nontypeable Haemophilus influenzae conjugated to proteins confers protection against otitis media in chinchillas

“…Chinchilla, gerbil, and rat models have been developed to study OM (16,21,31), and among them, chinchillas provide the best available model for NTHi OM (19). Direct challenge of the ME with NTHi is more stringent and reliable than a nasopharyngeal challenge in terms of controlling the amount of bacteria introduced (1, 2, 21).…”