Comparative Analysis Of Preoperative, Intraoperative, And Postoperative Bacteriological Results And Drug Sensitivity Tests In Chronic Suppurative Otitis Media

Objective: The research aims at investigating bacterial cultureand drug sensitivitytests before, during and after the mastoidectomy, andassessing the dynamic changes of bacterial culture of chronic suppurative otitismedia (CSOM). We expected that our study could promote the use of empiricalantibiotic therapy for CSOM in clinic, and enable patients to get timely andeffective antibiotic therapy before and after operation, improve cure rate aftermastoidectomy and reduce the incidence of complications. Methods: Thespecimens were all collected from86hospitalized patients with CSOM inOtolaryngology Head and Neck Surgery Department of The Third People’sHospital of Chongqing, from November2012to August2013, who experiencedmastoidectomy by the same surgeon. Before operation, the secretions were tookwith small swab from deep ear canal where near the eardrum, or from tympaniccavity. During operation, tissues or secretions were collected using sterilecurette from the area of mastoid and tympanic antrum, or tympanic antrumentrance. At10to14days after operation, sponges and secretions were took insurgical cavity with small swab after removing the antibiotic gauze from earcanal. The secretions and tissues were collected for bacterial culture and drugsensitivity tests, and the results were analyzed between the patients with andwithout cholesteatoma. Results：(1) Hospitalized CSOM patients with positiveculture results preoperatively, intraoperatively and postoperatively were65cases (75.6%),36cases41.9%) and1case (1.2%),respectively. Significantdifferences were found between preoperative and intraoperative positive ratesof bacteria culture (χ2=20.172, P<0.001), as well as between intraoperative andpostoperative positive rates of bacterial culture (χ2=42.182, P<0.001). Besides, the common bacteria and their distributions of preoperation and intraoperationwere mostly the same, mainly including Staphylococcus aureus, Pseudomonasaeruginosa, coagulase-negative staphylococcus and Proteus.(2) Before theoperation, positive bacteria were found in57cases, positive fungus in8casesand no pathogenic bacteria in21cases. But during the operation,correspondingly, positive bacteria was found in28cases (49.1%),2case(25.0%) and6cases (28.6%) respectively. Bacteria from the preoperative andintraoperative culture were exactly the same in28patients, and totally differentin4pairs.8cases with single bacterial growth in preoperative bacteriologicalresults were changed into other mixed bacterial growth in intraoperative culture.(3) Positive rates of bacterial culture between the CSOM patients with andwithout cholesteatoma were not significantly different preoperatively(χ2=0.014,P>0.05), but significantly different intraoperatively (χ2=11.517, P<0.05); nosignificant differences of the constituent ratio were found in the mainlypathogens of the two groups preoperatively and introperatively(P>0.05).(4) Inintraoperative samples, no significant differences of positive rates were foundbetween pyogenic fluids and tissues (χ2=0.134, P>0.05), as well as tissues ofmastoid tympanic antrum area and tympanic antrum entrance area (χ2=0.222,P>0.05).(5)28pairs with the same bacteria cultured preoperatively andintraoperatively were compared by drug sensitivity tests, of which6pairs(21.4%) were not the same.(6) The bacteria in the study included fivemethicillin-resistant Staphylococcus aureus(MRSA), three methicillin-resistantcoagulas-negative Staphylococci (MRCNS), while no ciprofloxacin-resistantPseudomonas aeruginosa (CRP) was found. All40strains of staphylococcusaureus showed high sensitivity to vancomycin, linezolid, nitrofurantoin,quinupristin/DafuPu, tigecycline, and have a moderate sensitivity to rifampin,oxacillin, cotrimoxazole, gentamicin, moxifloxacin, tetracycline, but a lowersensitivity to penicillin G, clindamycin, erythromycin, ciprofloxacin,levofloxacin. All27strains of pseudomonas aeruginosa showed high sensitivity to amikacin, cefepime, and a moderate sensitivity to gentamicin, tobramycin,levofloxacin, ciprofloxacin, ceftazidime, piperacillin, meropenem, imipenem,and100%resistance to ampicillin, ampicillin/sulbactam, cefazolin, cefuroxime,cefotetan, ceftriaxone, nitrofurantoin, trimethoprim-sulfamethoxazole.Conclusion：(1) The common bacteria and their distributions of preoperationand intraoperation were mostly the same, mainly including Staphylococcusaureus, Pseudomonas aeruginosa, coagulase-negative staphylococcus andProteus.(2) Intraoperative bacteriological results showed the different bacteriaand drug sensitivity from the preoperative bacteriological results, and patientswith preoperative negative culture results might show positive results inintraoperative culture.(3) compared to the CSOM patients withoutcholesteatoma, CSOM patients with cholesteatoma were more likely to beinfected by bacteria; no significant differences of the constituent ratio werefound in the mainly pathogens of the two groups preoperatively andintroperatively.(5) therefore, it is necessary to carry out dynamic detection onbacterial culture and drug sensitivity tests before, during and after the operation,and adjust the kinds of antibiotics according to the bacteria changes and itssusceptibility timely, in order to achieve the better surgical outcome.