Otomicroscopic findings and systemic interleukin-6 levels in relation to etiologic agent during experimental acute otitis media.
ABSTRACT The aim of the present study was to explore whether it was possible to differentiate the clinical course and the otomicroscopic appearance of acute otitis media (AOM) caused by common otitis pathogens in an animal model. Systemic interleukin (IL)-6 levels as early markers for bacterial AOM were also studied. Four groups of rats were inoculated with either Streptococcus pneumoniae, Streptococcus pyogenes, non-typeable Haemophilus influenzae or Moraxella catarrhalis. The animals were monitored by otomicroscopy, photos of the tympanic membrane, cultures and IL-6 detection in serum the following 4 days. The gram-positive S. pneumoniae and S. pyogenes induced severe AOM with opaque effusion behind the tympanic membrane, pronounced dilation of the vessels and spontaneous perforations. The gram-negative H. influenzae and M. catarrhalis induced a less severe infection with cloudy, sometimes foamy effusion, and no spontaneous perforations. With the otomicroscopic findings it was possible to distinguish between infections induced by gram-positive bacteria and gram-negative bacteria. Detection of interleukin-6 in serum appeared to be of limited use for all infections except the pneumococcal AOM, but this needs to be further investigated.
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ABSTRACT: Background Leukotrienes are the major factors in the formation of edema and mucus, as well as development of tuba Eustachii dysfunction in acute otitis media. We developed an experimental acute suppurative otitis media model and compared the responses of rats to penicillin and combinations of leukotriene antagonist with respect to histopathological observations conducted in early and late phases. Material and Methods A total of 83 ears from 56 Wistar rats were used in this study. Pneumococcus suspension was injected trans-tympanically into all rats. Subjects were classified into 4 different groups with 14 rats in each. In Group A, intramuscular penicillin G was injected for a period of 5 days. In Group B, intraperitoneal montelukast was injected for 21 days in addition to penicillin. In Group C, intraperitoneal montelukast isotonic NaCl in Group D was injected into rats for 21 days. Results No significant difference was found between the groups, except for mucosal vascularization with respect to mucosal and TM parameters in early phases. Furthermore, considerable deviations were observed for the recuperation of TM and mucosal inflammation for groups in which subjects were injected with montelukast as compared to other groups of the study in the late phases. Conclusions When the parameters of inflammation in the rat middle ear were compared with each other, most of these parameters did not show any statistically significant beneficial effects in montelukast and penicillin groups.01/2013; 19:246-52. DOI:10.12659/MSMBR.889474
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ABSTRACT: Otitis media (OM) is one of the most frequent diseases in childhood, and Streptococcus pneumoniae is among the main causative bacterial agents. Since current experimental models used to study the bacterial pathogenesis of OM have several limitations, such as the invasiveness of the experimental procedures, we developed a non-invasive murine OM model. In our model, adapted from a previously developed rat OM model, a pressure cabin is used in which a 40 kPa pressure increase is applied to translocate pneumococci from the nasopharyngeal cavity into both mouse middle ears. Wild-type pneumococci were found to persist in the middle ear cavity for 144 h after infection, with a maximum bacterial load at 96 h. Inflammation was confirmed at 96 and 144 h post-infection by IL-1beta and TNF-alpha cytokine analysis and histopathology. Subsequently, we investigated the contribution of two surface-associated pneumococcal proteins, the streptococcal lipoprotein rotamase A (SlrA) and the putative proteinase maturation protein A (PpmA), to experimental OM in our model. Pneumococci lacking the slrA gene, but not those lacking the ppmA gene, were significantly reduced in virulence in the OM model. Importantly, pneumococci lacking both genes were significantly more attenuated than the DeltaslrA single mutant. This additive effect suggests that SlrA and PpmA exert complementary functions during experimental OM. In conclusion, we have developed a highly reproducible and non-invasive murine infection model for pneumococcal OM using a pressure cabin, which is very suitable to study pneumococcal pathogenesis and virulence in vivo.Microbiology 09/2009; 155(Pt 12):4135-44. DOI:10.1099/mic.0.033175-0 · 3.06 Impact Factor
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ABSTRACT: Background:Leukotrienes are found to be the major factors in the formation of edema and mucus as well as development of tuba Eustachii dysfunction in acute otitis media. Montelukast sodium is a receptor antagonist of selective cystenyl leukotriene and exerts its effects through connecting to the receptor of cys leukotriene1. To develop an experimental acute suppurative otitis media model and compare the responses of rats to penicillin and combinations of leukotriene antagonist with respect to histopathological observations conducted at both early and late phases. Material and Methods: A total of eighty-three ears from fifty six Winstar rats used in this study. Pneumococcus suspension was injected transtympanically to all the rats. Subjects were classified under four different groups having 14 rats at each. In Group A, Intramusculer penicilline G was injected to for a period of five days. In Group B, intraperitoneal montelukast was injected for 21 days in addition to penicilline. In Group C, intraperitoneal montelukast, isotonic NaCl in Group D was injected to rats for 21 days. Cross-sections were semi-quantitatively graded with respect to various inflammatory components. Results: No significant difference was found between the groups, apart from mucosal vascularization with respect to mucosal and TM parameters at early phases. Furthermore, considerable deviations were observed for the recuperation of TM and mucosal inflammation for groups where subjects were injected with montekulast as compared to other groups of the study at the late phases. Conclusions: When the parameters of inflammation in the rat middle ear were compared with each other, most of these parameters did not show any statistically different beneficial effects in montelukast and penicillin groups.Medical science monitor: international medical journal of experimental and clinical research 07/2013; · 1.22 Impact Factor