Actual antibiotic resistance pattern of Brucella melitensis in central Anatolia. An update from an endemic region.

OBJECTIVE: To test in vitro susceptibilities of Brucella melitensis (B. melitensis) blood isolates obtained from an endemic region, by broth microdilution susceptibility test. METHODS: Fifty blood isolates were tested with anti-brucella antibiotics, namely, tetracycline, gentamicin, streptomycin, ceftriaxone, ciprofloxacin, levofloxacin, ofloxacin, and rifampin. All of the clinical isolates belonged to the group of B. melitensis biotype-3. This study was performed at the Clinical Microbiology Laboratory of the Medical School of Ondokuz Mayis University, Samsun, Turkey, in 2005. RESULTS: In terms of minimum inhibitory concentration-90 (MIC90) values, tetracycline (MIC90 0.25 microgram/mL) and rifampin (MIC90 0.5 microgram/mL) still continue to be the most effective antibiotics; however, ceftriaxone and streptomycin demonstrated higher MIC values, although they were still effective in vitro against B. melitensis strains with MIC90 of 8 microgram/mL. CONCLUSION: All first line, and alternative antimicrobial agents could be used in various combinations in the treatment of human brucellosis. High MIC values of ceftriaxone and streptomycin are alarming, and should be closely monitored during the therapy.

[Short communication: use of cefoxitin disc diffusion method for the detection of methicillin resistance in Staphylococcus aureus clinical isolates]. / Kisa bildiri: Staphylococcus aureus klinik izolatlarinda metisilin direncinin tespiti için sefoksitin disk difüzyon yönteminin kullanimi.

The aim of this study was to compare the cefoxitin disc diffusion method with oxacillin broth microdilution and agar screening methods for the detection of methicillin-resistant Staphylococcus aureus (MRSA). The presence of PBP2a in 94 S. aureus clinical isolates were screened by latex agglutination MRSA-Screen test (Oxoid Ltd, UK), and 64 (68%) of the strains were found positive. Cefoxitin disc diffusion method and oxacillin broth microdilution and agar screening methods were performed in the guidance of Clinical and Laboratory Standards Institute (CLSI) proposals. All of the 64 PBP2a positive isolates were found resistant, and 30 PBP2a negative isolates were detected as susceptible to oxacillin by both of the broth microdilution and agar screening methods. In cefoxitin disc diffusion method, zone diameters of 62 isolates were measured as 0-14 mm, while two isolates gave 15-17 mm and 30 isolates gave 220 mm zone diameters. According to the CLSI proposals, 64 isolates were accepted as oxacillin-resistant in view of their cefoxitin zone diameters. As a result, the sensitivity and specificity of cefoxitin disc diffusion method was detected as 100%, when comparing with both gold standard (PBP2a presence) method and oxacillin broth microdilution and agar screening methods, indicating that it is a reliable test to investigate oxacillin resistance of clinical S. aureus isolates in routine laboratories where molecular tests could not be performed due to economical reasons.

[Surveillance study of vancomycin resistant enterococci in pediatric haematology and oncology patients]. / Cocuk hematoloji ve onkoloji hastalarinda vankomisine dirençli enterokok sürveyansi.

In this study, the prevalence and risk factors of fecal carriage of vancomycin resistant enterococci (VRE) among patients in Ondokuz Mayis University Pediatric Hematology and Oncology Clinics have been investigated. During two months, rectal swab samples were collected weekly from all of the patients hospitalized in Pediatric Hematology and Oncology Clinics, for the surveillance cultures. During the study a total of 85 rectal swabs were obtained from 34 patients who had been hospitalized in the inpatient clinic with 20 bed capacity. The number of samples obtained from the patients varied between 1-6 cultures. All of the patients (100%) had peripheral venous catheters and 27(79%) of patients had used antibiotics. All of the samples were inoculated onto 8 microg/ mL gentamicin containing blood agar media, and enterococci were identified by Gram staining, catalase test and at species level by VITEK 2 (bioMérieux, France) automated system. Vancomycin resistance was screened by using 6 microg/mL vancomycin containing brain-heart infusion agar according to CLSI guidelines. The vancomycin MIC values of the strains grown in this medium were determined by microdilution test proposed by CLSI. As a result, a total of 50 samples (59%) belonging to 24 patients yielded enterococci, and the species distribution was as follows; E. faecium (in 16 cases), E. faecalis (in 8 cases), E. casseliflavus (in 6 cases), E. avium (in 3 cases) and E. durans (in 1 case). In our study no vancomycin resistance nor VRE colonization was detected in the patients.