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WOS: 000387771500004 PubMed: 28124959 Deaths related with human immunodeficiency virus (HIV) infections have been decreased by the introduction of combined anti-retroviral therapy (ART) into the clinical practice. Combined ART usually consists of two nucleoside/nucleotide analogs reverse transcriptase inhibitors (NRTI) that is called backbone and a third drug that belongs to either non-nucleoside/nucleotide reverse transcriptase inhibitors (NNRTI), protease inhibitors (PI), integrase strand transfer inhibitors (INSTI) or entry inhibitors. During abacavir therapy which is a member of NRTI, hypersensitivity reactions can occur approximately 4-9% of the patients that lead difficulties for the management of HIV infections. It is known that, the development of hypersensitivity reactions to abacavir is strongly associated with the presence of HLA-B*57:01 allel, therefore, HLA-B*57:01 screening should be performed prior to abacavir use. Since there is no data on HLA-B*57:01 prevalence in HIV-1-infected cases in Turkey, this is the first study that screened HLA-B*57:01 allels among HIV-1 infected adults in Turkey. A total of 100 HIV-1-infected patients (81 male, 19 female; mean age: 42.31 +/- 11.97 years) who have admitted to the Department of Infectious Diseases and Clinical Microbiology of Ondokuz Mayis University School of Medicine, Samsun, Turkey, were included in the study. Genomic DNAs were isolated from the blood samples of patients by using a commercial spin column procedure (QIAamp (R) DNA Blood Mini Kit; QIAGEN GmbH, Germany). HLA-B*57:01 genotyping was performed by the method of sequence-specific primer (SSP)-based amplification using a commercial OlerupSSP (R) HLA-B*57:01 high-resolution test kit (Olerup SSP AB, Sweden) according to the manufacturer's protocol. The products of polymerase chain reaction were electrophoresed on a 2% agarose gel stained with Olerup SSP GelRed dye (Olerup SSP AB, Sweden), and the bands were evaluated under UV light. In our study, three (2 male, 1 female) out of 100 patients were found positive for HLA-B*57:01 gene with a prevalence of 3%, which is a moderate level. Although the medical usefulness of HLA-B*57:01 screening before the abacavir therapy is emphasized, it was also noted that this application is not cost-effective for the populations with low HLA-B*57:01 prevalence, in contrast to populations with high prevalence. Considering of the incidence of HIV/AIDS in Turkey which is 0.12, the value and cost-effectiveness of HLA-B*57:01 screening in HIV-1 positive cases before abacavir therapy should be analysed by further studies.

Pekmezci, Gokmen Zafer/0000-0002-7791-1959; WOS: 000355774200018 …

WOS: 000350946600012 PubMed: 25706737 Aeromonas spp. are oxidase positive, gram-negative, facultative anaerobic bacilli that are widely distributed in aquatic environments. A.hydrophila, A.sobria and A.bestiarum may cause severe infections in both human and cold-blooded animals. Environmental persistance of quinolones that are widely used in both human and veterinary medicine plays an important role in the selection of resistant mutants. Plasm id-mediated resistance is one of the main mechanisms involved in quinolone resistance, and qnr, qepA, aac(6')-Ib-cr, oqxAB genes are identified as resistance determinants. Determination of various types of qnr gene in different bacteria mainly in Enterobacteriaceae, suggests that they are widely distributed in nature. Recently, plasmid-mediated quinolone resistance was defined among Aeromonas species isolated from water. The aim of this study was to investigate the presence of qnr genes among aquatic Aeromonas spp. in Turkey. A total of 45 Aeromonas strains isolated from water and fishes collected from three different geographical regions (Aegean, Mediterranean and Blacicsea) in Turkey, were included in the study. The isolates were identified at species level by the use of 16S rDNA-RFLP (Restriction fragment length polymorphism) analysis and multiplex polymerase chain reaction (M-PCR). Among the isolates, 20 were identified as A.sobria, 10 as A.hydrophila, nine as A.salmonicida, four as A.bestiarum and two as A.veronii. The plasmid-mediated quinolone resistance determinants, qnrA, qnrB, qnrC and qnrS genes, were investigated by M-PCR, and sequence analysis was performed for nine qnr-positive isolates. According to the sequence analysis of the genes, qnr genes were characterized in six A.sobria, in two A.bestiarum and in one A.hydrophila isolate (9/45; 20%). When the sequence was compared with GenBank database, this gene was found as qnrS2. All qnrS-positive Aeromonas spp. isolates were ciprofloxacin-susceptible, while five of them were resistant to nalidixic acid. This study is the first research about the plasmid-mediated quinolone resistance and the presence of qnrS2 genes among Aeromonas spp. isolated from fishes and water in Turkey. In conclusion, various resistance genes of aquatic bacteria may constitute a potential risk for the transmission of those genes to other bacteria as well as clinical isolates.

WOS: 000339539000008 PubMed: 23390904 Treatment of drug-resistant Mycobacterium tuberculosis infections requires combination of anti-tuberculosis drugs which have several toxic side effects. Thus there is a need for safer and effective new drugs. Ankaferd Blood Stopper (R) (ABS), which is a mixture of plant extracts prepared from Alpinia officinarum, Glycyrrhiza glabra, Thymus vulgaris, Urtica dioica and Vitis vinifera, has homeostatic and antibacterial effects. Standard solutions of ABS are already being used topically for post-traumatic and post-operative bleeding control in our country. This study was aimed to evaluate the in vitro activity of ABS against M.tuberculosis isolates. A total of 57 clinical isolates [17 multidrug resistant (MDR), 11 resistant to only isoniazid (INH), one resistant to INH and streptomycin (STR), two resistant only to STR, two resistant only to ETM, and 24 susceptible to all drugs] and three standard strains [H37Rv (susceptible to all drugs), ATCC 35822 (INH-resistant), ATCC 35820 (SIR-resistant)] were included in the study. Agar dilution method was used to detect the MIC values of ABS. In the study, ABS MIC value was determined as 10.94 mu g/ml for M.tuberculosis H37Rv strain which was susceptible to all antituberculosis drugs, whereas it was determined as 21.88 mu g/ml for INH-resistant ATCC 35822 and SIR-resistant ATCC 35820 strains. The MIC values for 24 susceptible clinical isolates were as follows; 10.94 mu g/ml (n= 17), 21.88 mu g/ml (n= 6) and < 1.37 mu g/ml (n= 1). When evaluating 17 MDR clinical isolates, MIC values were determined as 5.47 mu g/ml (n= 1), 10.94 mu g/ml (n= 5) and 21.88 mu g/ml (n= 11). MIC values were ranging between < 1.37-21.88 mu g/ml among 11 INH-resistant isolates. These isolates were susceptible to other first line anti-tuberculosis drugs. MIC value of one isolate resistant to both of INH and SIR was determined as 21.88 mu g/ml. MIC value of the two sole STR-resistant isolates was 21.88 mu g/ml. MIC values of the two sole ETM-resistant isolates were determined as 21.88 mu g/ml and 10.94 mu g/ml. MIC,c, and MIC90 values for the tested bacteria were 10.94 mu g/ml and 21.88 mu g/ml, respectively. It was concluded that 16 fold diluted concentration of the topically used ABS solution was found to be active against tuberculosis bacilli in vitro. Thus ABS might be used as a supportive agent together with anti-tuberculous drugs during debridement of multiple drug-resistant M.tuberculosis caused osteomyelitis and lymphadenitis lesions.

Bozdogan, Bulent/0000-0001-8846-7649; Nohut, Okan Kadir/0000-0002-8111-8072; BOZDOGAN, BULENT/0000-0003-2469-9728 WOS: 000308115400004 PubMed: 22951649 Fluoroquinolones which are in use since 1986, are effective agents both against gram-positive and gram-negative bacteria. Quinolones show bactericidal effect as a result of inhibition of DNA gyrase and topoisomerase IV enzymes. Main quinolone resistance mechanisms are chromosomal mutations in these enzymes and decreased intracellular accumulation due to efflux pumps or decreased membrane uptake. Recently a new quinolone resistance mechanism mediated by plasmids has been defined. These plasmids carry genes called as qnr. Qnr genes do not cause quinolone resistance but they cause decreased quinolone susceptibility and lead to higher minimum inhibitory concentrations. Currently there are qnrA, qnrB, qnrC, qnrD and qnrS genes. This study was aimed to investigate the presence of plasmid-mediated quinolone resistance determinants in Enterobacteriaceae isolates collected from four different centers in Turkey. A total of 647 isolates (387 from Trabzon, Black Sea region; 82 from Canakkale, Trace region; 96 from Ankara, Central Anatolia region; 82 from Tokat, Black Sea region) belonging to the Enterobacteriaceae family collected between May-July 2009, were included in the study. Presence of qnrA, qnrB, qnrS and qnrC genes were investigated by multiplex polymerase chain reaction (PCR) method and confirmed by gene sequencing. The results of the PCR amplification revealed that 2 isolates were positive for qnrA, 12 isolates were positive for qnrB, 4 isolates were positive for qnrC and 10 isolates were positive for qnrS. However, the number of positive strains decreased with the use of gene sequencing, and this method led to the identification of qnrA1 in two isolates [Enterobacter cloacae (code. 796), Salmonella group B (code. 491)), qnrB1 in two isolates [Salmonella group B (code. 491), Citrobacter freundii (code. 768)], qnrB6 in one isolate [Escherichia coli (code. CC1800)], qnrB9 in one isolate [E.coli (code. CC1873)], qnr1324 in one isolate [Citrobacter koseri (code. MP5200)], qnrB27 in one isolate [C.freundii (code. 842)], qnrS1 in two isolates [E.coli (code. CC1705), E.coli (code.159)] and qnrB2 in one isolate [E.coli (code. 843)]. One of the isolates that carried the qnr gene was ciprofloxacin-resistant and two isolates were nalidixic-acid resistant. Transferable quinolone resistance due to the dissemination of qnr genes may have important impacts in terms of infection control and treatment problems. Survey of plasmid mediated quinolone resistance will help to determine the size of the issue and guide the measures that should be taken to avoid escalation of resistance and dissemination problem.

WOS: 000297000100005 PubMed: 22090292 This study was aimed to evaluate the performance of blood agar for the growth of mycobacteria from clinical specimens sent to Mycobacteriology Laboratory of Samsun Chest Diseases Hospital. One hundred fifty six clinical specimens including 123 sputum, 28 bronchoalveolar lavage (BAL) and 5 pleural fluid specimens were inoculated in Lowenstein-Jensen (LJ), BACTEC MGIT 960 system (Becton Dickinson, USA) and blood agar following decontamination process. The specimens were also simultaneously examined for the presence of acid-fast bacilli (AFB). Thirty five mycobacteria strains (33 Mycobacterium tuberculosis and 2 atypical mycobacteria) grew in blood agar, 38 (36 M.tuberculosis and 2 atypical mycobacteria) in LJ media and 46 (44 M.tuberculosis and 2 atypical mycobacteria) in BACTEC MGIT 960 system. Among 29 AFB negative specimens, 20 revealed growth in both blood agar and LJ medium and 27 in MGIT system. AFB positive 20 samples yielded growth in 15 samples in blood agar, 18 in LJ medium and 19 in MGIT system. Among the total of 156 samples, contamination was observed in 15 (9.6%) samples in blood agar, 16 (10.2%) in LJ medium and 18 (11.5%) in MGIT system. Growth time was 5-35 days (mean 18 +/- 7.4), 11-35 days (mean 19 +/- 5.9) and 5-15 days (mean 10 +/- 2.4) for blood agar, LJ medium and BACTEC MGIT 960 system, respectively. The three samples which revealed contamination in BACTEC MGIT 960 system, grew successfully in both blood agar and 14 medium without contamination. In one sample, growth was observed only in LJ medium but neither in blood agar nor BACTEC MGIT 960 system. However, in another sample, growth was observed only in blood agar while no growth was detected in LJ or BACTEC MGIT 960 system. Six samples yielded mycobacteria only in BACTEC MGIT 960 system. These results indicated that simultaneous use of one liquid and one solid medium to grow mycobacteria from the clinical samples seemed to be complementary. Blood agar was a promising choice since it was found to be as effective as LJ medium for the growth of mycobacteria, however, this issue needs to be further evaluated in a multicentre study with a larger specimen collection.

WOS: 000275480700022 PubMed: 20455414 It was previously shown that statins have anti-inflammatory, immunomodulatory and anti-oxidant effects. This study was aimed to investigate the in-vitro antibacterial effects of simvastatin and atorvastatin. In this study antibacterial activity of the statins were tested against 16 methicillin-susceptible Staphylococcus oureus (MSSA), 16 methicillin-resistant S.oureu5 (MRSA), 16 methicillin-resistant coagulase-negative Stophylococcus (MRCoNS), 9 vancomycin-susceptible Enterococcus faecium, 7 vancomycin-susceptible Enterococcus fGecaiis, 13 vancomycin-resistant Efaecium, 16 extended spectrum beta-lactamase (ESBIL) positive Escherichio coli, 16 Pseudomonos aeruginoso, 16 Acinetobacter boumannii, 15 ESBIL positive Klebsieflo prieumoniae, 6 Stenotrophomonas moltophilio by broth microdilution method according to the Clinical and Laboratory Standards Institute (CLSI) performance and interpretive guidelines. S.oureus ATCC 29213, S.aureus ATCC 25923, S.oureus ATCC 43300, Enterococcus faecofis ATCC 29212, K.pneumoniae ATCC 700603 and E.coli ATCC 35218 were tested as control strains. The results showed that minimum inhibitory concentration (MIC) values for all isolates were > 128 mu g/mI for the two statins tested. However, MIC of simvastatin was 32 pg/ml for S.oureus ATCC 29213 and was 64 mu g/ml for S.oureus ATCC 25923 and Efoecolis ATCC 29212 and was > 128 mu g/ml for others, but MIC of atorvastatin was > 128 mu g/ml for all standard strains. According to these results, we observed that simvastatin and atorvastain had no significant antibacterial effect in vitro. In this study, although no antibacterial effect of statins were determined in vitro, further studies are needed to investigate the combined effect of statins with antibacterial agents in the living organism.

WOS: 000271840400006 PubMed: 20084909 Pseudomonas aeruginosa is a frequent cause of respiratory infections in cystic fibrosis (CF) patients. P.aeruginosa strains isolated from these patients have often a mucoid phenotype at advanced disease. This mucoid structure contains a dense amount of alginate type polysaccharide which facilitates bacterial attachment to lung epithelia and provides protection from the immune system due to biofilm formation. The aims of this study were to investigate the biofilm formation and the relation of this property with genotype and antibiotic susceptibilities of P.aeruginosa strains isolated from CF patients. The biofilm formation was determined by using the Congo Red agar and Christensen methods. RAPD-PCR (Random amplification of polymorphic DNA polymerase chain reaction) and disc diffusion methods were used for genotyping and antibiotic susceptibility testing, respectively. Biofilm production was found positive in 33.3% (20/60) of P.aeruginosa tested. While 9 of these 20 isolates were of mucoid colony morphotype, among the 40 biofilm negative isolates mucoid colony was detected in 16 of them. RAPD genotyping based on 70% similarity yielded 19 (A-S) clusters and subtypes related to five of these clusters (K1, K2, N1, N2, Q1, Q2, R1, R2, S1, S2) making up a total of 24 genotypes. Nine of these genotypes composed of biofilm positive isolates and 15 were biofilm negative ones. Most of the biofilm positive strains belonged to K1 (n = 5) and K2 (n = 6) genotypes while biofilm negative isolates were in the L (n = 8) and O (n = 7) genotypes. The comparison of antibiotic susceptibilities in both groups revealed no statistically significant difference (p > 0.0%). However, highest rate of resistance was detected for tobramycin and lowest rate for piperacillin/tazobactam. The data obtained from this study indicated that biofilm negative and positive P.aeruginosa isolates clustered in different groups. These results should be supported with larger scale multi-center studies which may provide information about P.aeruginosa dynamics in CF lungs.

WOS: 000269119300012 PubMed: 19795621 Effective efflux pump systems play a crucial role in the development of multiple antimicrobial resistance in bacteria. In this study, the effects of an efflux pump inhibitor 1-(1-naphthylmethyl)-piperazine on ciprofloxacin (CIP) minimum inhibitory concentration (MIC) values in gram-negative bacteria including Escherichia coli, Pseudomonas aeruginosa and Klebsiella pneumoniae were investigated. Nineteen CIP-resistant P. aeruginosa, 37 extended spectrum beta-lactamase (ESBL) positive E. coli and 13 ESBL positive K. pneumoniae clinical isolates were included to the study. CIP MIC values of each isolate were determined by broth microdilution method as recommended by CLSI. MIC values were determined also in the presence of 100 mu g/ml NMP. CIP MICs for all isolates were 4 mu g/ml or higher. In the presence of 100 mu g/ml NMP, CIP MICs did not change for Poeruginoso isolates. While MICs decreased >= 4-fold for 22 (59.4%) E. coli isolates, 2-fold decrease was detected only for 14 (37.8%) isolates. MIC value did not change for 1 isolate. While MICs decreased >= 4-fold for 10 (76.9%) K. pneumoniae isolates, >= 2-fold decrease was detected for 3 (23.1%) isolates. In conclusion, while NMP consistently reduced the MIC of ciprofloxacin in E. coli and K. pneumoniae clinical isolates, no effects was observed in P. aeruginosa isolates.

WOS: 000265949300014 PubMed: 19621615 Tuberculosis continues to be a serious public health problem worldwide. Since multi-drug resistant strains of Mycobacterium tuberculosis constitutes a serious problem in tuberculosis control, new and more effective chemotherapeutic agents are required. This study was aimed to investigate the in vitro effect of linezolid alone and in combination with isoniazid and rifampicin against 10 multidrug resistant M.tuberculosis isolates by using the checkerboard method. Checkerboard testing was performed by the broth microdilution method, using Middlebrook 7H9 broth with 10% oleic acid-albumin-dextrose-catalase. Antibiotic combinations were tested at concentrations of 0.06-4 mu g/ml for linezolid and 0.03-32 mg/ml for isoniazid and rifampicin. The results were evaluated according to the calculated fractional inhibitory concentration (FIC) index. All clinical isolates were found to be susceptible to linezolid; MICs of linezolid were 0.25 mu g/ml for two strains and 0.5 mu g/ml for the other strains. While rifampicin MIC values were > 32 mu g/ml for all the isolates, isoniazid MIC values were 4 mu g/ml for two isolates, 8 mu g/ml for six isolates, 16 mu g/ml for one isolate and 32 mu g/ml for one isolate. In this study, synergism was detected in only one strain between linezolid and isoniazid (FIC index: 0.265). Although synergy was observed between linezolid and isoniazid just for one strain, further larger scale in vitro and in vivo studies are necessary to evaluate the effect of different drug combinations against multidrug-resistant M.tuberculosis strains.

WOS: 000271840400016 PubMed: 20084919 Sertralin is a psychotropic drug which acts by inhibiting the selective serotonin re-uptake in the synaptic area. Previous studies have shown that some antidepressant agents have antibacterial activity. The aim of this study was to investigate the in vitro antibacterial activity of sertralin. A total of 224 bacterial strains isolated from clinical specimens together with standard control strains were included to the study. The antibacterial activity of sertralin was determined by microdilution method in Mueller-Hinton broth according to the Clinical and Laboratory Standards Institute (CLSI) guideline. The minimum inhibitory concentration (MIC) values were found to be 4-32 mu g/ml for 22 methicillin-susceptible Staphylococcus aureus strains, 16-32 mu g/ml for 25 methicillin-resistant S.aureus strains, 8-32 mu g/ml for 20 methicillin-resistant coagulase-negative staphylococci strains, 16-32 mu g/ml for 4 vancomycin-susceptible Enterococcus faecalis strains, 0.5-32 mu g/ml for 10 vancomycin-susceptible Enterococcus faecium strains, 2-8 mu g/ml for 12 vancomycin-resistant E.faecium strains, 16-128 mu g/ml for 21 Acinetobacter baumannii strains, 4->128 mu g/ml for 20 Klebsiella pneumoniae strains, 0.25-128 mu g/ml for 24 Escherichia coli strains, 64->128 mu g/ml for 22 Pseudomonas aeruginosa strains, 128->128 mu g/ml for 2 Proteus vulgaris strains, 64->128 mu g/ml for 8 Proteus mirabilis strains, 32->128 mu g/ml for 7 Stenotrophomonas maltophilia strains, 32-128 mu g/ml for 21 Enterobacter cloacae strains and 8-128 mu g/ml for 6 Enterobacter aerogenes strains. The MIC values of sertralin against standard strains were as follows; 16 mu g/ml for S.aureus ATCC 29213 (methicillin-susceptible), 32 mu g/ml for S.aureus ATCC 43300 (methicillin-resistant), 16 mu g/ml for E.faecalis ATCC 29212, 32 mu g/ml for K.pneumoniae ATCC 700603, 32 mu g/ml for E.coli ATCC 25922 and > 128 mu g/ml for P.aeruginosa ATCC 27853. Sertralin has showed antibacterial activity mainly against gram-positive bacteria, and it was surprising that MIC values of vancomycin-resistant enterococci were lower than those of vancomycin-susceptible ones. Further in vivo and in vitro studies are required to provide reliable data about the use of sertralin as an adjuvant agent in the antibacterial treatment of infections caused by multidrug-resistant bacteria.

WOS: 000263117000003 PubMed: 19334376 Brucella spp. replicate and survive in lympho-proliferative tissues and cells, thus effective treatment of brucellosis requires the combined and long term use of intracellularly active antibiotics. Elimination of the microorganism largely depends on the reactive oxygen and nitrogen intermediates released by activated macrophages. In this study we aimed to determine the in vitro activity of hydrogen peroxide (H2O2; reactive oxygen intermediate) and acidified sodium nitrite (ASN; reactive nitrogen intermediate) alone and in combination with rifampicin (RIF) and tetracycline JET) against four clinical isolates of Brucella melitensis. Initially minimal inhibitory concentrations of RIF and TET were determined by microbroth dilution susceptibility test. The activity of 2 and 5 mM H2O2 and 3 and 6 mM ASN was tested against each isolate by direct colony count from the agar plates inoculated with bacterial suspensions treated with H2O2 or ASN. The last step in the assay was to determine the combined effectiveness of RIF and TET plus H2O2 and ASN. From each three rolls of assay apparatus samples were taken at 0., 1., 6. and 24. hours and inoculated on Brucella agar. The plates were incubated at 37 degrees C for 48 hours and colonies were counted. While RIF alone or in combination with H2O2 supressed the growth of bacteria even in the first hour, TET alone did not show any effect in 24 hours. However, in combination with reactive oxygen and nitrogen intermediates TET affected bacterial growth starting from six hours. In conclusion, further explanation of the interactions between antibiotics and the substances produced by the immune system of the host during the infections caused by intracellular pathogens, might have an important impact on the determination of the treatment protocols and the measures to prevent relapses.

WOS: 000260856700003 PubMed: 19149076 The aim of this study was to investigate the effects of efflux pump inhibitors on the minimal inhibitory concentration (MIC) values of ciprofloxacin (CIP) in fluoroquinolone-resistant 42 Pseudomonas aeruginosa (n= 42), Escherichia coli (n= 97), Acinetobacter baumannii (n= 58) and Staphylococcus aureus (n= 80) strains isolated from clinical specimens. Par this purpose phenylalanyl-arginyl-beta-naphthylamide (PA beta N) was used for P.aeruginosa, E.coli, A.baumannii and reserpine for S.aureus isolates as pump inhibitors. Fluoroquinolone resistance of the clinical isolates were determined by VITEK2 Compact (BioMerieux, France) automated system and confirmed with standard broth microdilution method. For the investigation of the effects of inhibitor agents, the MIC values were also determined in the presence of 25 mu g/ml and 100 mu g/ml PA beta N and 20 mu g/ml reserpine. In the presence of 25 mg/l PA beta N, 61.9% of CIP resistant P.aeruginosa strains converted to susceptible ones, while this rate was 73.8% in the presence of 100 mg/l PARN. In A.baumannii clinical isolates, 8.6% and 15.5% of CIP-resistant strains have become susceptible in the presence of 25 mg/l and 100 mg/l PARN, respectively. Similarly the MIC values for CIP have decreased >= 4 folds in 42.2%, and >= 2 folds in 30.9% of E.coli isolates, in the presence of 25 mg/l PARN, however, there was no change in MICs of 26.9% of E.coli strains. The MIC values have also been lowered for >= 4 folds in 83.6%, and two folds in 13.4% of E.coli strains by the use of 100 mg/l PARN concentration, however, no decrease in MIC values was detected in 3% of the isolates. 20 mg/l of reserpine have caused a decrease of >= 4 folds in 8.75%, and two folds in 33.75% of S.aureus isolates, while there was no change in MIC values of 57.5% of S.aureus strains. Our results showed that PARN causes significant reduction in MIC values for CIP in the clinical isolates of P.aeruginosa, E.coli and A.baumannii and this effect may be attributed to efflux pump inhibition. In contrast, it was concluded that reserpine does not have a considerable effect on the MIC values of S.aureus against ciprofloxacin.

WOS: 000258416900013 PubMed: 18822892 The aim of this study was to evaluate the use of chocolate agar as an alternative medium instead of Middlebrook 7H10 agar, for the susceptibility testing of Mycobacterium tuberculosis strains against isoniazid (INH), rifampicin (RIF), streptomycin (STR) and ethambutol (ETM). The susceptibility results obtained by chocolate agar were compared with the results of BACTEC 460 TB (Becton Dickinson, Sparks, MD, USA) system which was accepted as the reference method. A total of 25 M. tuberculosis clinical isolates were included to the study and susceptibility testing was performed on malachite green added-chocolate agar with some modifications of proportion method recommended by NCCLS. In our study when comparing the results obtained by chocolate agar with the results of BACTEC 460 TB system, the concordance rates for INH, STIR, RIF and ETM were found as 88%, 88%, 84% and 72%, respectively. The specificity, sensitivity, positive and negative predictive values of susceptibility testing on chocolate agar have been detected as 82.3%, 100%, 72.7% and 100% for INH; 78.5%, 100%, 78.5% and 100% for RIF; 83.3%, 84.2%, 94.1% and 62.5% for STR; 25%, 94.1%, 72.7% and 66.6% for ETM, respectively. The results of the susceptibility testing performed on chocolate agar were obtained on the 21(st) day of incubation for all isolates. In conclusion, the data from our study suggested that chocolate agar can be used as an alternative medium for the susceptibility testing of M. tuberculosis, however, further studies with more isolates are needed for the standardisation of the method.