%0 Journal Article %T Comprehensive Analysis of Bacterial Flora in Postoperative Maxillary Cyst Fluid by 16S rRNA Gene and Culture Methods %A Naoto Sano %A Yoshio Yamashita %A Kazumasa Fukuda %A Hatsumi Taniguchi %A Masaaki Goto %A Hiroshi Miyamoto %J ISRN Dentistry %D 2012 %R 10.5402/2012/840483 %X Intracystic fluid was aseptically collected from 11 patients with postoperative maxillary cyst (POMC), and DNA was extracted from the POMC fluid. Bacterial species were identified by sequencing after cloning of approximately 580£¿bp of the 16S rRNA gene. Identification of pathogenic bacteria was also performed by culture methods. The phylogenetic identity was determined by sequencing 517¨C596£¿bp in each of the 1139 16S rRNA gene clones. A total of 1114 clones were classified while the remaining 25 clones were unclassified. A total of 103 bacterial species belonging to 42 genera were identified in POMC fluid samples by 16S rRNA gene analysis. Species of Prevotella (91%), Neisseria (73%), Fusobacterium (73%), Porphyromonas (73%), and Propionibacterium (73%) were found to be highly prevalent in all patients. Streptococcus mitis (64%), Fusobacterium nucleatum (55%), Propionibacterium acnes (55%), Staphylococcus capitis (55%), and Streptococcus salivarius (55%) were detected in more than 6 of the 11 patients. The results obtained by the culture method were different from those obtained by 16S rRNA gene analysis, but both approaches may be necessary for the identification of pathogens, especially of bacteria that are difficult to detect by culture methods, and the development of rational treatments for patients with POMC. 1. Introduction Three theories, that is, the retention cyst, cleft cyst, and closed cavity theories, have been proposed for the formation of postoperative maxillary cysts (POMCs) [1¨C3], which are a long-term delayed complication arising from years to decades after radical operations such as the Caldwell-Luc operation for maxillary sinusitis [4, 5]. This complication is generally known as POMC, although other terms are also found in the literature, such as postoperative buccal cyst, postoperative wangenzyste, mucocele, postoperative paranasal cyst, surgical ciliated cyst, and respiratory implantation cyst [6]. These cysts are considered rare in the West, whereas cysts in the maxillooral region constitute 20% of reported cysts in Japan [6]. They grow painlessly in the maxillary sinus where they are often perceived through swelling or pain in the maxillary mucobuccal fold and buccal region. Other symptoms noted with significant cyst growth include nasal obstruction, rhinorrhea, dysosmia, exophthalmos, and ocular displacement. Bacterial infections in the oral cavity may be closely related to cyst growth and subsequent symptoms [4]. Over 600 bacterial species have been detected in the oral cavity [7], and the majority of these are viable but not %U http://www.hindawi.com/journals/isrn.dentistry/2012/840483/