Saliva, supragingival biofilm and root canals can harbor gene associated with resistance to lactamic agents

This study aimed to determine the presence of Prevotella strains and genes associated with resistance to lactamics in different oral niches from patients with/without primary endodontic infections. Saliva (S) and supragingival biofilm (SB) were collected from three patient groups: Group I – no endodontic infection (n = 15); Group II – acute endodontic infection (n = 12); and Group III – chronic endodontic infection (n = 15). Root canal (RC) samples were collected from Groups II and III. The presence of P. intermedia, P nigrescens, P. tannerae and cfxA/cfxA2 gene was assessed by PCR. The cfxA/cfxA2 gene was not detected in all environments within the same patient. The cfxA/cfxA2 gene was present in 23.81% of S samples, 28.57% of SB samples, and 7.41% of RC samples. Prevotella species were detected in 53.97%, 47.62% and 34.56% of the S, SB, and RC samples, respectively. P. intermedia had a high frequency in saliva samples from Group 3. Saliva samples from Group 1 had higher detection rates of P. nigrescens than did Groups 2 and 3. Patients without endodontic disease had high frequencies of P. nigrescens in the SB samples. The presence or absence of spontaneous symptoms was not related to the detection rates for resistance genes in the RC samples. Saliva, supragingival biofilm and root canals can harbor resistant bacteria. The presence of symptomatology did not increase the presence of the cfxA/cfxA2 gene in the supragingival biofilm and inside root canals.

本研究旨在明确伴/不伴原发性牙髓感染的患者不同口腔生态位中普雷沃菌（Prevotella）菌株及与乳酸胺类（lactamics）耐药相关的基因分布情况。本研究共纳入3组患者：组I为无牙髓感染患者（n=15）；组II为急性牙髓感染患者（n=12）；组III为慢性牙髓感染患者（n=15）。采集所有受试者的唾液（S）及龈上生物膜（SB）样本，同时采集组II与组III患者的根管（RC）样本。采用聚合酶链式反应（PCR）检测中间普雷沃菌（P. intermedia）、变黑普雷沃菌（P. nigrescens）、坦纳普雷沃菌（P. tannerae）及cfxA/cfxA2基因的存在情况。未在同一患者的所有口腔生态位中同时检出cfxA/cfxA2基因。cfxA/cfxA2基因在唾液样本中的检出率为23.81%，龈上生物膜样本中为28.57%，根管样本中为7.41%。普雷沃菌属菌种在唾液、龈上生物膜及根管样本中的检出率分别为53.97%、47.62%及34.56%。组III患者的唾液样本中，中间普雷沃菌的检出频率较高。组I患者的唾液样本中，变黑普雷沃菌的检出率高于组II与组III。无牙髓疾病的患者，其龈上生物膜样本中变黑普雷沃菌的检出频率较高。根管样本中耐药基因的检出率与自发症状的有无无相关性。唾液、龈上生物膜及根管内均可携带耐药菌。症状的存在并未增加龈上生物膜及根管内cfxA/cfxA2基因的检出率。