Detection of plasmid-mediated quinolone resistance in clinical isolates of Enterobacteriaceae strains in Hamadan, West of Iran.

Plasmid mediated quinolone resistance (PMQR) determinants have arisen as a significant concern in recent years. The aim of this study was screening of resistant-clinical isolates to fluoroquinolone antibiotics and detection of qnr and aac(6')-Ib-cr genes. For this purpose we collected 100 fluoroquinolone-resistant Enterobacteriaceae which were from 3 hospitals in Hamadan, west provinces of Iran, between October 2012 and June 2013. The all samples were identified by biochemical tests and confirmed by PCR method. Antimicrobial susceptibility to 14 antimicrobial agents including levofloxacin and ciprofloxacin were determined by disk diffusion methods and ciprofloxacin MIC was obtained by broth microdilution method as Clinical Laboratory Standards Institute (CLSI) recommendations. The isolates were screened for the presence of qnrA, qnrB, qnrS and aac(6')-Ib-cr genes using PCR assay. Among the screened isolates, 64 strains (64%) of Escherichia coli, 23 strains (23%) of Klebsiella pneumoniae, 13 strains (13%) of Proteus mirabilis were collected as quinolone-resistant isolates. out of 100 isolates, two (2%) were positive for qnrS, seventeen (17%) isolates were positive for qnrB and we did not find qnrA gene in any of the isolates. There were also 32 positive isolates for aac(6')-Ib-cr determinant. We described the prevalence of qnr and aac(6')-Ib-cr genes in fluoroquinolone-resistant Enterobacteriaceae in Hamadan city. The carriage rate of multidrug-resistant Enterobacteriaceae in healthy people in Hamadan City is extremely high. Moreover, genes encoding transferable quinolones, in particular aac(6')-Ib-cr, are highly prevalent in these strains.

Identification of Group B Streptococci Using 16S rRNA, cfb, scpB, and atr Genes in Pregnant Women by PCR.

Streptococcus agalactiae is acommensalorganism, but it may cause infection in susceptible hosts. The aim of this study was to evaluate PCR assay compared with conventional culture method for direct detection of Streptococcus agalactiae. Total of 203 paired low vaginal swabs were collected from women at 35-37 weeks of pregnancy from June 2013 through February 2014 for detection of Streptococcus agalactiae using PCR assay targeting 16S rRNA, cfb, scpB, and atr genes and culture method following broth enrichment. The results were recorded and evaluated for determining of sensitivity, specificity, positive and negative predictive values of PCR assaycompared with culture method. Prevalence of Streptococcus agalactiae was determined as 7.39% (n=15) using culture method; 19.70% (n=40) by PCR targeting 16S rRNA gene; 18.23% (n=37) by targeting atr gene; 17.24% (n=35) by cfb gene; and 8.87% (n=18) by scpB gene. Generally, a total of 49 specimens were considered true positive (27 samples by PCR assay using the four genes in sum, 4 samples only by atr gene PCR, 3 samples only by cfb gene PCR, 2 samples only by culture method, and 13 samples by PCR assay and culture method in common) and prevalence of Streptococcus agalactiae determined 24.14% in Hamadan. The current data demonstrated that performing only culture method for detecting GBS from pregnant women leads to missed false negative carrier individuals. Thus, it is recommended that both the PCR assay and conventional culture method to be performed in order to detect Streptococcus agalactiae.

Effect of apically separated rotary instruments on bacterial leakage of obturated root canals using resilon.

The purpose of this study was to determine the effect of a separated rotary instrument on the time required for bacterial penetration of obturated root canals using Resilon. Eighty-four extracted human maxillary premolars with single canals were used in this study. Group 1 consisted of teeth obturated with gutta-percha and AH-26 sealer (n=15); Group 2 consisted of teeth obturated similarly to Group 1 but without a separated file; Group 3 consisted of teeth obturated with Resilon and Epiphany sealer (n=15); and Group 4 consisted of teeth obturated similarly to Group 3 but without a separated file. Six teeth were used as positive controls, and six teeth were used as negative controls for each experimental group. Negative controls were obturated similarly to experimental teeth. On the other hand, positive controls were obturated with gutta-percha or Resilon without sealer. A suspension of Enterococcus faecalis was placed in the access chamber daily, and penetration was determined when turbidity was noted in the culture broth during a three-month period. No significant difference between experimental groups was observed. However, differences between experimental groups and control groups were statistically significant.

Antimicrobial effect of three new and two established root canal irrigation solutions.

This study sought to assess the efficacy of two established and three relatively new root canal irrigants against five different microorganisms using the agar diffusion method. Sodium hypochloride (NaOCl)-based irrigants demonstrated the most effective antimicrobial activity.

Bacterial microleakage and post space timing for two endodontic sealers: an in vitro study.

AIM: The effects of immediate versus delayed post space preparation on the apical seal using resin and zinc oxide eugenol (ZOE) sealers were compared by a bacterial leakage model. METHODOLOGY: Eighty-six premolars were randomly assigned to four experimental groups of 20 teeth. Three teeth were assigned to each control group, either positive (filled only with guttapercha) or negative (not obturated but root surfaces completely covered). Obturation was achieved by gutta-percha with resin or gutta-percha with a ZOE sealer and lateral condensation technique. Post space was prepared either immediately or a week later, while the obturated teeth had been stored in 100 percent relative humidity at 37 degrees C. The teeth were inserted into plastic vials and suspended in glass bottles. All teeth were covered with cyanoacrylate and layers of nail varnish but the apical 3 mm and were sterilized using gamma rays. Phenol red lactose broth was inoculated into the vials. Staphylococcus epidermidis was introduced into the root canal access of the teeth. Turbidity of the broth in the vials (discoloration) was evaluated daily for a period of 70 days. The data was analyzed statistically with Pearson Chi Square and two ways with ANOVA at 45 days and 70 days. RESULTS: When the depth of time was considered, the mean time of leakage showed no differences between immediate and delayed preparation for resin AH26 versus ZOE Dorifil at 45 and 70 days (p = 0.37 and p = 0.217, respectively). In 45 days, considering the number of teeth with leakage, there was a significant difference between immediate preparation and delayed preparation in AH26 sealer groups (p = 0.028). No difference was present between immediate and delayed preparation groups for the ZOE sealer groups (p = 0.14). CONCLUSION: According to the results of this study and despite type of sealer, immediate post space preparation did not achieve better sealing than delayed post space preparation. Resin AH26 showed the least leaking teeth in 45 days, but it made no difference in 70 days.

Urinary tract infections: bacteriology and antibiotic resistance patterns.

The aim of this study was to identify the bacteria causing community acquired urinary tract infections (UTI) and detection of antibiotics resistance of isolates in 912 children below 18 years in the west of Iran. Data were analyzed for 4 age groups: infants, toddlers, preteens and teens. Fourteen antibiotics were tested by gel-diffusion method. Of 912 patients, 34.2% had positive bacterial cultures. The most common isolates were E. coli (57.4 %), K. pneumoniae (9.7 %), S. aureus (5.8%) and A. baumannii (2.2%). Most isolates showed high resistance against ampicillin, cotrimoxazole, nalidixic acid, tobramycin and nitrofurantoin. Klebsiella isolates showed more resistance against tested antibiotics than E. coli isolates.