Molecular investigation of staphylococcal cassette chromosome mec types and genotypic relations of methicillin-resistant staphylococci isolated from before and after hospital exposed students.

Background: Reservoir of methicillin resistance genes called staphylococcal cassette chromosome mec (SCCmec), plasmids and genomic characterisations of isolates have been widely investigated in epidemiologic research. However, the extent to which these organisms are transported by patients or hospital staff is not entirely clear. Aim: This study aims to investigate the molecular relatedness and plasmid profiles of MR staphylococci isolated from nursing students before and after hospital training, to find out the possible source. Materials and Methods: This study examined 39 methicillin-resistant (MR) staphylococci and 2 inducible clindamycin-resistant, methicillin-susceptible Staphylococcus aureus. Specimens were collected before and after 4 months of hospital training from the hands and nares of 75 nursing students. A polymerase chain reaction technique was used to confirm the existence of mecA gene and identify SCCmec types; total DNA was digested by SmaI endonuclease restriction to monitorise clonal relatedness by pulsed-field gel electrophoresis (PFGE); plasmid profiles were monitorised on agarose gel. Results: All 39 isolates tested positive for mecA; SCCmec type III was observed most frequently. Interestingly, in one isolate of Staphylococcus epidermidis, four different types of SCCmec elements were observed. There were 23 different types of plasmids, whose sizes ranged from 1.4 to 46.0 kb. After PFGE dendogram analysis, two strains were classified as indistinguishable; six were closely related. Most of the isolates obtained after hospital training showed clonal similarity and seven had multiple SCCmec elements require further investigation for the possible mechanism. Conclusion: Most of the isolates obtained after hospital training showed clonal similarity and seven had multiple SCCmec elements require further investigation for the possible mechanism.

[Investigation of intestinal parasites among elementary school students in the Mugla province]. / Mugla Ili Merkez Ilkögretim Okulu Ögrencilerinde Bagirsak Parazitleri Arastirilmasi

OBJECTIVE: In this study prevalence of intestinal parasite agents was investigated among elementary school students in the Mugla city centre. METHODS: Only 663 relatives among 3560 students allowed us to investigate and obtain fecal specimens of the students. Specimens were examined by native and lugol staining. Repeated samples were requested from suspected cases and evaluated. RESULTS: Intestinal parasites were found in 73 stool specimens (11.01%) taken from students. The frequently observed parasite was Ascaris lumbricoides at ratio of 52% (39 students). CONCLUSION: It was estimated that, because of the lack of a sewage system in the Mugla province, health education and periodically parasite examinations should be administered to elementary school students and their families in order to raise awareness and prevent parasitic infections.

[Investigation of the effects of efflux pump inhibitors on ciprofloxacin MIC values of high level fluoroquinolone resistant Escherichia coli clinical isolates]. / Yüksek düzey florokinolon dirençli Escherichia coli klinik izolatlarinda efluks pompa inhibitörlerinin siprofloksasin MIK degerleri üzerine etkilerinin arastirilmasi.

In this study, effects of efflux pump inhibitors, phe-arg-beta-naphthylamide (MC-207,110), verapamil, omeprazole and lansoprazole, on ciprofloxacin minimal inhibitory concentrations (MIC) against Escherichia coli clinical isolates with high level fluoroquinolone (FQ) resistance, were evaluated. Fourteen FQ resistant clinical isolates of E. coli isolated from urine samples and identified by BD BBL CRYSTAL Identification Systems Enteric/Nonfermenter ID kit (Becton Dickinson and Company Sparks, USA) were tested. In order to investigate the effects of inhibitory agents, MIC values were determined by broth microdilution method in the absence or presence of 20 microg/ml MC-207,110, verapamil, omeprazole and lansoprazole. All 14 clinical isolates were resistant to ciprofloxacin (MIC range; 16-512 microg/ml). No difference was observed on ciprofloxacin MIC values in the presence of 20 microg/ml omeprazole, whereas MIC values were decreased 2 folds in 2 isolates in the presence of verapamil and lansoprazole, 2 folds in 6 isolates and 4 folds in 2 isolates in the presence of MC-207,110. In conclusion, we observed that there were no effects of the compounds used in our study, on ciprofloxacin resistance of E. coli clinical isolates.

Drug susceptibility testing of Mycobacterium tuberculosis with nitrate reductase assay.

The nitrate reductase assay (NRA) was evaluated for susceptibility testing of Mycobacterium tuberculosis using 80 clinical isolates of M. tuberculosis and H37Rv as a control strain. All isolates were tested by the proportion method and the NRA for isoniazid (INH), rifampicin (RIF), streptomycin (STR) and ethambutol (ETM). The proportion method was carried out according to NCCLS on Löwenstein-Jensen (LJ) medium and the NRA on LJ medium containing 1000 microg/ml potassium nitrate (KNO(3)). After incubation for 7, 10, 14 and 21 days, Griess reagent was added to each LJ medium and nitrate reduction was determined by a colour change. Comparing the NRA with the proportion method, sensitivities were 100, 100, 82.1 and 92.2% for INH, RIF, STR and ETM, respectively. Specificities were 100, 100, 92.3 and 100% for INH, RIF, STR and ETM, respectively. The results of 2, 22 and 56 isolates were obtained after 7, 10 and 14 days, respectively. The proportion method result were read at 21-28 days. The NRA is rapid, inexpensive and easy to perform. Our results indicated that the NRA is suitable for the early determination of INH and RIF resistance in countries where sophisticated procedures are not always available.

Drug susceptibility testing of Mycobacterium tuberculosis by the broth microdilution method with 7H9 broth.

In this study, we have evaluated the broth microdilution method (BMM) for susceptibility testing of Mycobacterium tuberculosis. A total of 43 clinical isolates of M. tuberculosis and H37Rv as a control strain were studied. All isolates were tested by the proportion method and the BMM for isoniazid (INH), rifampicin (RIF), streptomycin (STR), and ethambutol (ETM). The proportion method was carried out according to the National Committee for Clinical Laboratory Standards (NCCLS) on Löwenstein-Jensen (LJ) medium. The BMM was carried out using 7H9 broth with 96 well-plates. All strains were tested at 3.2-0.05 micro g/ml, 16-0.25 micro g/ml, 32-0.5 micro g/ml, and 32-0.5 micro g/ml concentrations for INH, RIF, STR, and ETM, respectively. When the BMM was compared with the proportion method, sensitivity was 100, 100, 96.9, and 90.2%, while specificity was 100, 85.7, 90.9, and 100% for INH, RIF, STR, and ETM, respectively. The plates were examined 7, 10, 14, and 21 days after incubation. The majority of the result were obtained at 14th days after incubation, while the proportion method result were ended in 21-28 days. According to our results, it may be suggested that the BMM is suitable for early determining of multidrug-resistance-M. tuberculosis strains in developed or developing countries.

A multidrug efflux pump inhibitor reduces fluoroquinolone resistance in Pseudomonas aeruginosa isolates.

In general, resistance to fluoroquinolones (FQs) in gram-negative bacteria is acquired either by mutations in DNA gyrase and topoisomerase IV or by active export of the agents via antibiotic efflux pumps. Reduced porin expression is also proposed to be another mechanism leading to resistance. In this study, interaction between levofloxacin, ofloxacin, and ciprofloxacin with MC-207,110 (multidrug efflux pump inhibitor) was investigated by a checkerboard assay using Pseudomonas aeruginosa. Levofloxacin, ofloxacin, and ciprofloxacin were tested at different concentrations (0.06-64 microg/ml) and MC-207,110 was tested at a concentration range of 4-128 microg/ml. In the presence of MC-207,110 (at 128, 64, 32, 16 microg/ml) resistance to FQs was inhibited significantly and MIC values were decreased, except at 8 and 4 microg/ml of MC-207,110. When MC-207,110 was used, resistance of P. aeruginosa to FQs in vitro was inhibited significantly, suggesting that MC-207,110 may be useful for use in clinical treatment protocols to overcome FQs resistance.

Drug susceptibility testing of Mycobacterium tuberculosis by the broth microdilution method with 7H9 broth

In this study, we have evaluated the broth microdilution method (BMM) for susceptibility testing of Mycobacterium tuberculosis. A total of 43 clinical isolates of M. tuberculosis and H37Rv as a control strain were studied. All isolates were tested by the proportion method and the BMM for isoniazid (INH), rifampicin (RIF), streptomycin (STR), and ethambutol (ETM). The proportion method was carried out according to the National Committee for Clinical Laboratory Standards (NCCLS) on Lõwenstein-Jensen (LJ) medium. The BMM was carried out using 7H9 broth with 96 well-plates. All strains were tested at 3.2-0.05 µg/ml, 16-0.25 µg/ml, 32-0.5 µg/ml, and 32-0.5 µg/ml concentrations for INH, RIF, STR, and ETM, respectively. When the BMM was compared with the proportion method, sensitivity was 100, 100, 96.9, and 90.2 percent, while specificity was 100, 85.7, 90.9, and 100 percent for INH, RIF, STR, and ETM, respectively. The plates were examined 7, 10, 14, and 21 days after incubation. The majority of the result were obtained at 14th days after incubation, while the proportion method result were ended in 21-28 days. According to our results, it may be suggested that the BMM is suitable for early determining of multidrug-resistance-M. tuberculosis strains in developed or developing countries.

[Antibacterial effect of nitric oxide]. / Nitrik oksitin antibakteriyel etkisinin arastirilmasi.

In this study, the antibacterial effects of nitric oxide (NO) have been investigated against 4 strains of multidrug-resistant Mycobacterium tuberculosis and 8 Klebsiella, 7 Escherichia coli, 7 Staphylococcus, 5 Enterobacter, 7 Pseudomonas and 7 Proteus clinical isolates by using DETA-NO ((Z)-1-[N-(2-aminoethyl)-N-(2-ammonioethyl)amino]diazen-1-ium-1,2-diolate) as the NO donor. Minimum inhibitory concentrations (MICs) were determined by broth microdilution method for all tested microorganisms. The MIC values found in our study were as follows; 0.25 mg/ml for all of the multidrug-resistant Mycobacterium tuberculosis strains, 1 mg/ml for Staphylococcus strains, and approximately 2 mg/ml for the rest of the bacterial strains. These results showed that NO (or NO donor DETA-NO) was more effective on multidrug-resistant M. tuberculosis strains than the other bacterial species. It can be concluded that further studies are needed to explain the clinical use of NO donor DETA-NO, especially, in patients infected with multidrug-resistant M. tuberculosis.

[In vitro susceptibility of Salmonella enterica serovar Typhimurium to reactive oxygen and nitrogen products]. / Salmonella enterica serovar Typhimurium'un reaktif oksijen ve nitrojen ara ürünlerine in-vitro duyarliligi.

The aim of this study was to investigate the in-vitro susceptibility of Salmonella enterica serovar Typhimurium against reactive oxygen and nitrogen intermediates, on five different strains. SH5014 as a parental strain, PP120 as a soxRS mutant, SH7616 as a acrAB efflux pump mutant, SZH KUEN 557 as a standard strain and a clinical isolate, were included to the study. Hydrogen peroxide (at 0.125, 0.25, 0.5 mM concentrations) as reactive oxygen intermediate (ROI) and DETA-NO (at 1, 2, 4 mg/ml concentrations) as nitric oxide donor, in addition with acidified sodium nitrite (at 25, 50, 100 mM concentrations) as reactive nitrogen intermediate (RNI) were used. As a result, susceptibility of PP120 to RNI and ROI was found similar with SZH KUEN 557 and the clinical isolate, while SH7616 and SH5014 were found more susceptible than the others. These data indicated that further studies were necessary on the genetic regulatory systems in Salmonella which control the resistance against RNI and ROI-dependent antimicrobial systems.

Comparison of the proportion method with mycobacteria growth indicator tube and E-test for susceptibility testing of Mycobacterium tuberculosis.

The aim of this study was to investigate the correlation between proportion method with mycobacteria growth indicator tube (MGIT) and E-test for Mycobacterium tuberculosis. Forty clinical isolates were tested. MGIT and E-test with the first line antituberculous drugs correlated with the proportion method. Our results suggested that MGIT and E-test methods can be routinely used instead of the proportion method.

Comparison of the Proportion Method With Mycobacteria Growth Indicator Tube and E-test for Susceptibility Testing of Mycobacterium tuberculosis

The aim of this study was to investigate the correlation between proportion method with mycobacteria growth indicator tube (MGIT) and E-test for Mycobacterium tuberculosis. Forty clinical isolates were tested. MGIT and E-test with the first line antituberculous drugs correlated with the proportion method. Our results suggested that MGIT and E-test methods can be routinely used instead of the proportion method