Bacterial change in external auditory canal upon antisepsis with povidone-iodine during tympanoplasty.

The aim of this single-arm prospective study was to determine the flora of the external auditory canal (EAC) in inactive chronic otitis media and evaluate the alteration of microorganisms of the EAC during tympanoplasty upon povidone-iodine antisepsis. Sixty-three patients with central tympanic membrane perforation were enrolled in the study. Preoperative swab cultures were obtained and the EAC was packed with povidone-iodine absorbed gauze. Type I tympanoplasty via a retroauricular route was performed. Cultures from the EAC were taken at the end of each operation. Isolated organisms were identified based upon microbiological, morphological, and biochemical characteristics. The most commonly isolated organisms from preoperative samples were normal commensal flora, including 73 coagulase-negative staphylococci (CNS) and 18 diphtheroid bacilli (DB). Less commonly cultured pathogenic species included four isolates of Staphylococcus aureus and three isolates of Candida albicans. No bacteria were observed in five patients. Following povidone-iodine antisepsis, 32 of the samples were negative. Eradication was statistically significant for CNS, DB and pathogen microorganism (P < 0.05). Isolated bacteria differed from those in preoperative swab cultures in eight cases. After antisepsis, diverse strains of the CNS were isolated in 13 cases and 10 patients showed no change in microbial flora. Postoperative culture demonstrated that all seven pathogenic isolates were eradicated (100 %); this selective efficacy of povidone-iodine antisepsis against pathogenic isolates was significant when compared with commensal flora (P < 0.05). These results suggest that povidone-iodine antisepsis of the EAC before tympanoplasty is an effective method for the elimination microorganisms, especially pathogenic bacteria.

Antimicrobial susceptibilities of Francisella tularensis subsp. holarctica strains isolated from humans in the Central Anatolia region of Turkey.

OBJECTIVES: To assess the in vitro susceptibility of Francisella tularensis subsp. holarctica biovar II strains to 24 antimicrobial agents. METHODS: Thirty-nine F. tularensis strains isolated from humans in the Central Anatolia region of Turkey were examined. Each isolate was identified by conventional and molecular techniques. MICs of aminoglycosides, tetracyclines, fluoroquinolones, macrolides, penicillins, cephalosporins, imipenem, clindamycin, linezolid, chloramphenicol and rifampicin were determined using the Etest method on glucose/cysteine blood agar plates. Interpretation of results was made according to CLSI clinical breakpoints. RESULTS: All strains were susceptible to aminoglycosides, tetracyclines, chloramphenicol, rifampicin and three fluoroquinolones. In contrast, resistance to penicillins, cephalosporins, carbapenems, macrolides and clindamycin was observed for all isolates. Fluoroquinolones had the lowest MIC(50) and MIC(90). CONCLUSIONS: All strains were susceptible to the antibiotics traditionally used to treat tularaemia, such as streptomycin (MIC(90) 1.5 mg/L), gentamicin (MIC(90) 0.25 mg/L), tetracycline (MIC(90) 0.38 mg/L) and chloramphenicol (MIC(90) 0.25 mg/L). Since fluoroquinolones showed the lowest MIC values, and have important advantages over aminoglycosides, including ease of oral administration and lower toxicities, quinolones have the potential for being effective first-line therapy for tularaemia.

[Comparison of oxacillin, cefoxitin, ceftizoxime, and moxalactam disk diffusion methods for detection of methicillin susceptibility in staphylococci]. / Stafilokoklarda Metisilin Duyarliliginin Belirlenmesinde Oksasilin, Sefoksitin, Seftizoksim ve Moksalaktam Disk Difüzyon Yöntemlerinin Karsilastirilmasi

Penicillin binding protein 2a/2' (PBP2a/PBP2') which is encoded by the mecA gene, is responsible for the methicillin resistance in staphylococci. Detection of methicillin resistance with phenotypic methods is still a problem especially because of heterogenous expression of mecA gene. Although mecA gene determination by polymerase chain reaction is considered as the gold standard method, molecular tests are not easily applied in all routine laboratories. Thus, for the rapid and accurate diagnosis of MRSA strains, easy and practical phenotypic tests are still required. This study was conducted to compare the oxacillin (OX), cefoxitin (CFX), ceftizoxime (CZX), and moxolactam (MOX) susceptibility testing by disk diffusion method for the detection of methicillin resistance in staphylococci. A total of 247 staphylococci (125 Staphylococcus aureus and 122 coagulase-negative staphylococci; CNS) isolated from various clinical specimens (114 wound and soft tissue materials, 51 urine, 48 blood, 30 respiratory tract, and four other samples) of inpatients and outpatients, were included in this study. PBP2a latex agglutination test was used as the reference method for the recognition of methicillin resistance; four antibiotic disks tested and sensitivity, specificity, positive and negative predictive values (PPV and NPV) were determined for each of them. According to PBP2a latex agglutination test 66 (54.1%) of CNS and 53 (42.4%) of S.aureus isolates were found methicillin- resistant. OX and MOX disks detected 113 (63 CNS and 50 S.aureus) methicillin-resistant strain out of 119 PBP2a positive isolates, where CFX and CZX disks detected 110 (60 CNS and 50 S.aureus) of them. Among 128 PBP2a negative isolates, 123 (52 CNS and 71 S.aureus) were detected as susceptible with OX, 127 (55 CNS and 72 S.aureus) with CFX and CZX, 126 (54 CNS and 72 S.aureus) with MOX. According to these results, the sensitivities and specificities of OX, CFX, CZX, and MOX disks were; 95.4% and 92.8%, 90.9% and 98.2%, 90.9% and 98.2%, 95.4% and 96.4%, respectively for CNS and 94.3% and 98.6%, 94.3% and 100%, 94.3% and 100%, 94.3% and 100%, respectively for S.aureus. The difference between sensitivities and specificities of tested antibiotic disks were not found statistically significant. In conclusion, due to the problems in detection of methicillin resistance with phenotypic methods, the use of different mecA gene-inducing antibiotic disks at the same time, and utilization of molecular methods as reference method might be suggested, when a discordance is observed between the antibiotic disks.

[An oropharyngeal tularemia case diagnosed by the isolation of Francisella tularensis on human blood agar]. / Francisella tularensis'in insan kanli agarda izole edilmesiyle tanimlanan bir orofarengeal tularemi olgusu.

Tularemia which is a multisystem disease of humans and some animals, is endemic in North America, some parts of Europe and Asia. The causative agent, Francisella tularensis, is a fastidious gram-negative, intracellular bacterium which requires supplementation with sulphydryl compounds (cysteine, cystine, thiosulphate, isoVitaleX) for growth on common laboratory media. In this report, a case of oropharyngeal tularemia diagnosed by the isolation of the causative agent on non-selective-common microbiological agar, has been presented. The patient was from Yozgat located in central Anatolia where tularemia has not been reported so far. Forty-two years old male was admitted to the hospital with two weeks history of sudden onset fever, headache, generalized aches, sore throat, and cervical tender lump on the left. Physical examination revealed bilateral exudative tonsillitis and tender posterior cervical lymphadenopathy. He has been empirically treated with amoxicilin-clavulanic acid for 7 days with initial diagnosis of acute tonsillopharyngitis. However, he was admitted to the hospital since the symptoms persisted and swelling increased despite antibiotic therapy. Microscopical examination of the Gram and Ehrlich-Ziehl-Neelsen stained smears prepared from the surgically drained lymph node revealed PMNL, with no evidence of bacteria. Routine cultures of the lymph node material yielded growth of gram-negative coccobacilli only on human blood agar and the cultures were negative for pyogenic bacteria, acid-fast organisms and fungi. Pathologic examination of the drainage material revealed suppurative inflammation. Lymph node aspirate and serum samples of the patient together with the isolated strain were sent to reference laboratory for further investigation in accordance to the clinical and laboratory findings compatible with tularemia. The isolate was confirmed as F.tularensis by slide agglutination and direct immunofluorescence antibody tests, and identified as F.tularensis subsp. holarctica by polymerase chain reaction. Microagglutination test performed on patient's serum yielded positive with an antibody titer of 1/5120. Gentamicin (5 mg/kg/day) was initiated, and the therapy was completed for two weeks. The patient recovered completely without sequela. This case was presented in order to call attention to the strain of F.tularensis which failed to demonstrate a requirement for cysteine and enriched medium on primary isolation, but grew well on conventional laboratory medium. Tularemia should be considered in the differential diagnosis of related infectious diseases since cases of tularemia have been reported from several parts of Turkey after the year 2004.