Background: The dissemination of extended-spectrum β-lactamases (ESBL) in Klebsiella pneumoniae isolates has resulted in the increase of antibiotic resistance and mortality among patients. The aim of this study was to determine the prevalence of ESBL and SHV-2a, SHV-5 and SHV-12 genes in K. pneumoniae isolates from Kermanshah.

Materials and Methods: In this descriptive – analytical study, from 112 clinical samples of patients admitted at Kermanshah medical centers in 2014, 60 K. pneumoniae isolates were recognized by standard methods of bacteriology and API Kit. Antibiotic susceptibility of isolates was determined by disk diffusion method and the isolates were screened for ESBL-producerig using the combination disc method. The SHV-2a, SHV-5 and SHV-12 genes were determined among isolates using PCR method. Primers were designed in this study.

Results: Of 60 isolates tested, the highest and the lowest resistance was for ampicillin and carbapenem antibiotics, respectively. Forty-five percent of isolates were ESBL-producer. Among 60 isolates tested, 5 (8.3%), 57 (95%) and 43 (71.7%) isolates contained SHV-2a, SHV-5 and SHV-12 genes, respectively. Five isolates contained all the three genes of SHV-2a, SHV-5 and SHV-12.

Conclusion: The results indicate the relatively high prevalence of SHV type beta-lactamase genes in K. pneumoniae isolates in Kermanshah. Given this high prevalence, the surveillance of antibiotic resistant patterns and relevant genes is necessary among gram-negative bacilli in Kermanshah region. Due to the high resistance of K. pneumoniae isolates to antibiotics and to reduce the dissemination of resistant genes, susceptibility testing to choose more affective antibiotics is recommended even for isolates from outpatients.

Background: The failure time of permanent tooth is of the form of interval censored since the exact time of tooth decay is not available and it is only known that tooth decay occurs between two consecutive visits. There are a few techniques available in the literature for the problem of goodness-of-fit for interval censored data. In this paper, we propose a new goodness-of-fit testing procedure for interval censored data and employ this for the failure time of the first permanent molar tooth (sixth tooth) data.

Materials and Methods: Two methods of goodness-of-fit for interval censored data that are based on randomly generated data from each interval and averaging over the test statistics or over the p-values are employed for the failure time of the first permanent molar tooth data.

Results:  The mean of the failure time of the first permanent molar tooth is found to be at 95 months. The p-values of the two goodness-of-fit testing procedures for the Weibull, log-normal and gamma models are calculated.

Conclusion: By comparing the p-values, the log-normal model is considered as the best model to describe the failure time of the first permanent molar tooth data.