[Short communication: Determination of methicillin resistance in staphylococci with different methods and detection of multiple antibiotic resistance]. / Kisa bildiri: Stafilokoklarda metisilin direncinin farkli yöntemlerle arastirilmasi ve coklu antibiyotik direncinin saptanmasi.

The aims of this study were to determine the methicillin resistance of a total of 256 staphylococcus strains [213 Staphylococcus aureus and 43 coagulase negative staphylococci (CNS)], isolated from different clinical samples and hospital environmental specimens by different methods and to detect multiple antibiotic resistance in these isolates. Methicillin resistance of staphylococci was investigated by using oxacillin agar screening (OAS), oxacillin disk diffusion (ODD), cefoxitin disk diffusion (CDD), PBP2a latex agglutination (LA) and microdilution tests. The resistance of the strains against penicillin G, amoxycillin/clavulanate, cephalothin, tetracycline, erythromycin, fusidic asid, ofloxacin, vancomycin, co-trimoxazole and gentamicin was investigated by standard disk diffusion method. As a result, 152 (71.3%) S. aureus and 30 (69.7%) CNS isolates were found to be methicillin-resistant with the use of OAS and PBP2a LA tests, respectively. The numbers of the isolates which were detected as methicillin-resistant and methicillin-susceptible were 182 and 74 by OAS; 183 and 73 by ODD; 181 and 75 by SDD; 180 and 76 by PBP2a LA; 183 and 73 by microdilution tests, respectively. There was no statistically significant differences-between the results obtained by all of the methods (p > 0.05), however the sensitivity of PBP2a LA test was lower in the detection of methicillin resistance in S. aureus strains. CDD test which was found to be as sensitive as ODD test, may be preferred in the detection of methicillin resistance in staphylococci. In our study staphylococci which were sensitive to methicillin, were also found generally sensitive to the other antibiotics, whereas staphylococci which were resistant to methicillin were also resistant to the other antibiotics. The difference between methicillin sensitive and resistant staphylococci in terms of the rates of resistance against other antibiotics was found statistically significant with the exception of fusidic acid (p < 0.05). The resistance rates of isolates for fusidic acid were very low and all of the strains were susceptible to vancomycin. In conclusion, for better determination of methicillin resistance, agar screening test which is proposed as a confirmatory test by CLSI, should be used when necessary.

[Investigation of hemodialysis patients in terms of the presence of occult hepatitis B]. / Hemodiyaliz hastalarinin gizli hepatit B varligi yönünden arastirilmasi.

The presence of hepatitis B virus (HBV) DNA in case of negative HBV surface antigen (HBsAg) in serum is known as "occult hepatitis B". There are many reports indicating that occult HBV infections are more frequently encountered in case of hepatocellular carcinoma, hemodialysis practice and co-infections with hepatitis C virus (HCV). The aim of this study was to investigate the presence of HBV-DNA in HBsAg negative hemodialysis. patients and subjects who had never experienced hemodialysis. A total of 226 HBsAg negative sera were included to the study, of which 153 were from hemodialysis patients (97 male, 56 female; mean age: 41.3 +/- 5.8 years), and 73 were from non-hemodialyzed individuals (46 male, 27 female; mean age: 36.5 +/- 6.9 years) who had serological evidence of previous HBV and HCV infections. Of these 73 subjects, 41 were anti-HCV positive, 22 were "anti-HBc IgG positive alone", seven were anti-HBc IgG and anti-HBs positive, and three were anti-HBc IgG and anti-HBe positive, while 40 of 153 (26.1%) hemodialysis patients were anti-HCV positive. HBV and HCV markers were detected by commercial enzyme immunoassays (bioMerieux, France and Murex, UK, respectively), and HBV-DNA testing was performed by a commercial real-time polymerase chain reaction (PCR; 5700 and 7700 Sequence Detection System, Applied Biosystems, UK) assay. Nineteen (12.4%) of HBsAg-negative hemodialysis patients and five (6.8%) of the non-hemodialyzed subjects were found positive for HBV-DNA (viral loads were > or =10(4) copies/ml, and 10(3)-10(4) copies/ml, repectively). The rates of occult HBV infection in the anti-HCV positive hemodialysis patients and anti-HCV positive non-hemodialyzed subjects were detected as 27.5% (11/40) and 2.4% (1/41), respectively. These rates in the other groups were found as follows; 7.1% (8/113) in the anti-HCV negative hemodialysis patients, 9.1% (2/22) in the "anti-HBc positive alone" subjects, and 20% (2/10) in the subjects positive for anti-HBc+anti-HBs or anti-HBe. The results of this study indicated that the prevalence of HBV viremia (12.4%) in hemodialysis patients being more prominent in those of anti-HCV positive patients (27.5%) should not be overlooked. In conclusion, the hemodialysis patients should be screened by sensitive PCR-based methods for occult HBV infections, even if they were negative for HBsAg, in order to prevent or at least to decrease the transmission risk of HBV infection which is still an important health problem in dialysis units.

[Investigation of the presence of Clostridium difficile in antibiotic associated diarrhea patients by culture and toxin detection methods]. / Antibiyotige bagli ishal olgularinda Clostridium difficile varliginin kültür ve toksin saptama yöntemleriyle arastirilmasi.

Clostridium difficile-associated disease can be observed especially in hospitalized patients who use broad-spectrum antibiotics. The aim of this study was to investigate the presence of C. difficile as the causative agent of diarrhea in outpatients and inpatients. During January-December 2005, 45 outpatients and 46 inpatients (of them 11 were intensive care unit patients) who had developed diarrhea due to antibiotic use, were included to the study. In addition 7 intensive care unit personnel and 20 food handlers were also included to the study in order to detect their carrier states. The age range of patients was 16-80 years, and of them 45 (49.5%) were male, while the age range of the personnel was 25-55 years, and of them 21 (78%) were male. Stool samples collected from the study groups were cultivated in C. difficile agar media (C. difficile Agar Base, Oxoid) as well as on routine bacteriologic media, and C. difficile growth was confirmed by latex agglutination test with the use of specific antisera. The presence of C. difficile toxin A was investigated by latex method (Oxoid, UK), and toxin A and B was searched by enzyme-linked immunoassay (ELISA; Seramun GmbH, Serazym C. difficile Toxin A+B), in the stool samples. While C. difficile was isolated from 13 (14.3%) of the 91 samples, no positive result was detected in the personnel. There was no statistically significant difference between outpatient and inpatient groups by means of C. difficile culture positivity (15.5% and 17.1%, respectively) (p>0.05). All of the culture positive samples were also found positive by ELISA Toxin A+B method (100%), but only 4 of them (30.7%) yielded positive result by Toxin A latex test. It was detected that 84.6% (11/13) of the patients had used ampicillin/sulbactam, 7.7% (1/13) used cotrimoxazole-SXT, and 7.7% (1/13) used macrolide antibiotics. The use of ampicillin/sulbactam was found statistically significant in development of diarrhea (p<0.05). Our data indicated that ELISA Toxin A+B is a reliable method with 100% specificity and sensitivity in the rapid diagnosis of C. difficile until the culture results were obtained, however, although specificity of Toxin A latex test is 100%, its use alone as a primary rapid diagnostic test was not recommended because of its low (30.7%) sensitivity.

[Isolation frequency of Burkholderia cepacia from cystic fibrosis patients]. / Kistik fibrozisli hastalarda Burkholderia cepacia izolasyon sikligi.

Microorganisms such as Pseudomonas aeruginosa, Staphylococcus aureus and Haemophilus influenzae frequently cause colonization and infection in airways of patients with cystic fibrosis. Burkholderia cepacia has also been isolated in patients with cystic fibrosis since 1980. In this study, we aimed to determine the colonization rate of B. cepacia in 286 sputum samples obtained from 129 cystic fibrosis patients. Selective media for B. cepacia were used besides the routine microbiological media in order to increase the isolation rate. The colonies were identified by biochemical tests and the antibiotic susceptibilities of the strains were determined by disc diffusion method. Pathogenic bacteria (S. aureus, P. aeruginosa, Enterobacteriaceae, Streptococcus pneumoniae, H. influenzae) were isolated in 52 of 129 patients (40%) and 66 of 286 sputum samples (23%). In addition 2 B. cepacia strains were isolated from two different patients (1.55%). B. cepacia is now being considered as a pathogen isolated from sputum samples of patients with cystic fibrosis with an increasing frequency and causing severe clinical features. According to these results it can be concluded that, the use of selective media for B. cepacia isolation, should be taken into consideration especially by the clinical microbiology laboratories collaborating with the cystic fibrosis centers.