Role of pathogenic oral flora in postoperative pneumonia following brain surgery

<p>Abstract</p> <p>Background</p> <p>Post-operative pulmonary infection often appears to result from aspiration of pathogens colonizing the oral cavity. It was hypothesized that impaired periodontal status and pathogenic oral bacteria significantly contribute to development of aspiration pneumonia following neurosurgical operations. Further, the prophylactic effects of a single dose preoperative cefazolin on the oral bacteria were investigated.</p> <p>Methods</p> <p>A matched cohort of 18 patients without postoperative lung complications was compared to 5 patients who developed pneumonia within 48 hours after brain surgery. Patients waiting for elective operation of a single brain tumor underwent dental examination and saliva collection before surgery. Bacteria from saliva cultures were isolated and periodontal disease was scored according to type and severity. Patients received 15 mg/kg cefazolin intravenously at the beginning of surgery. Serum, saliva and bronchial secretion were collected promptly after the operation. The minimal inhibitory concentrations of cefazolin regarding the isolated bacteria were determined. The actual antibiotic concentrations in serum, saliva and bronchial secretion were measured by capillary electrophoresis upon completion of surgery. Bacteria were isolated again from the sputum of postoperative pneumonia patients.</p> <p>Results</p> <p>The number and severity of coexisting periodontal diseases were significantly greater in patients with postoperative pneumonia in comparison to the control group (p = 0.031 and p = 0.002, respectively). The relative risk of developing postoperative pneumonia in high periodontal score patients was 3.5 greater than in patients who had low periodontal score (p < 0.0001). Cefazolin concentration in saliva and bronchial secretion remained below detectable levels in every patient.</p> <p>Conclusion</p> <p>Presence of multiple periodontal diseases and pathogenic bacteria in the saliva are important predisposing factors of postoperative aspiration pneumonia in patients after brain surgery. The low penetration rate of cefazolin into the saliva indicates that its prophylactic administration may not be sufficient to prevent postoperative aspiration pneumonia. Our study suggests that dental examination may be warranted in order to identify patients at high risk of developing postoperative respiratory infections.</p

Analysis and stability study of temozolomide using capillary electrophoresis

The applicability of micellar electrokinetic capillary chromatography (MEKC) for the analysis of temozolomide (TMZ) and its degradants, 3-methyl-(triazen-1-yl)imidazole-4-carboxamide (MTIC) and 5-amino-imidazole-4-carboxamide (AIC) has been studied. Using short-end injection, the analysis of TMZ and its degradants could be performed within 1.2 min. The obtained precision of migration times was better than 1.6 RSD%, and the limit of quantitation (LOQ) was 0.31–0.93ug/mL. The therapeutic concentration of TMZ in blood samples can be determined after direct sample injection and conventional on-capillary UV detection. The proposed MEKC method was applied to study the stability of TMZ in water and serum at different pH values. It was established that the half-life of the TMZ in vitro serum at room temperature was 33 min, close to the half-life (28 min) obtained in water at pH 7.9

Effectiveness of Cephalosporins in the Sputum of Patients with Nosocomial Bronchopneumonia

Nosocomial bronchopneumonia is a frequent complication in patients with chronic intratracheal intubation. Despite targeted antibiotic treatment, production of abundant bronchial secretion containing pathogen bacteria often tends to be chronic, and so mortality drastically increases. This problem led to an investigation of the penetration of five cephalosporin antibiotics into the sputum. Serum and sputum were collected from 24 chronically intubated patients having purulent nosocomial bronchopneumonia treated in an intensive care unit (ICU). Patients received the following doses intravenously every 24 h: five received 70 mg/kg of body weight cefuroxime, four received 110 mg/kg cefamandole, six received 80 mg/kg ceftriaxone, four received 80 mg/kg ceftazidime, and five received 80 mg/kg cefepime. Antibiotic concentrations in the serum and sputum were evaluated by capillary electrophoresis. MICs were determined for bacteria isolated from the purulent bronchial secretions. The mean levels of the cephalosporins in the sputum did not reach the MICs for the bacteria isolated from the same samples. Ceftriaxone was the only one of the investigated five cephalosporins that had a measurable concentration in the sputum (1.4 ± 1.2 mg/liter). The low concentration of antibiotics in the purulent tracheobronchial secretion can be one of the many reasons for ineffective therapy of nosocomial bronchopneumonia in intubated patients in the ICUs. In the case of intubated or mechanically ventilated patients having chronic bronchopneumonia, determination of drug concentration in the bronchial secretion might be considered when selecting an antibiotic for treatment