Résumé
Identification of Candida cultured from various clinical specimens to the species level is increasingly necessary for clinical laboratories. Although sn PCR identifies the species within hours but its cost-effectiveness is to be considered. So there is always a need for media which help in the isolation and identification at the species level. The study aimed to evaluate the performance of different chromogenic media and to compare the effectiveness of the traditional phenotypic methods versus seminested polymer-ase chain reaction [sn PCR] for identification of Candida species. One hundred and twenty seven Candida strains isolated from various clinical specimens were identified by conventional methods, four different chromogenic media and sn PCR . HiCrome Candida Differential and CHROMagar Candida media showed comparably high sensitivities and specificities in the identification of C. albicans , C. tropicalis, C. glabrata and C. krusei. CHROMagar Candida had an extra advantage of identifying all C. parapsilosis isolates. CHROMagar-Pal's medium identified C. albicans, C. tropicalis and C. krusei with high sensitivities and specificities, but couldn't identify C. glabrata or C. parapsilosis. It was the only medium that identified C. dubliniensis with a sensitivity and specificity of 100%. Biggy agar showed the least sensitivities and specificities. The overall concordance of the snPCR compared to the conventional tests including CHROMAgar Candida in the identification of Candida species was 97.5 %. The use of CHROMAgar Candida medium is an easy and accurate method for presumptive identification of the most commonly encountered Candida spp. Key words: chromogenic media, sn PCR, Candida?
Résumé
Extended spectrum beta lactamases producing Klebsiella pneumoniae [ESBL-KP] are an important cause of nosocomial infections in Intensive Care Units [ICUs]. We conducted a prospective study on 650 patients who were admitted to different adult ICUs at Assiut University Hospital to determine the incidence of ESBL-KP by phenotypic and genotypic methods. Phenotypic tests for ESBL were combined disc method, double disc synergy test [DDST] and E-test. Genotypic detection of ESBL bla TEM and bla SHV genes was carried out by polymerase chain reaction amplification [PCR]. The overall nosocomial infection incidence rate was 20% [130 patients]. Klebsiella pneumonia was isolated from 44 patients [34%], in which 23 isolates were found to be phenotypically ESBL producers. ESBL-KP was most frequently isolated from chest ICU [47.8%] and blood was the most frequent site of infection [8 isolates, 34%]. Based on Clinical and Laboratory Standards Institute [CLSI] screening test for ESBL, the combined disc method was the most sensitive [23/23, 100%] followed by the E-test [95.6%] and lastly the DDST [91.3%]. SHV gene was present in 8 isolates, TEM gene in 2 isolates, both SHV and TEM in 11 isolates and none of TEM or SHV in 2 isolates. Out of 950 environmental samples, Klebsiella pneumoniae was isolated from 48 samples [16.4%] in which 7 isolates [14.5%] were ESBL an genotyping revealed SHV in 4 strains, and both SHV and TEM in 3 strains
Conclusion: this study revealed the high incidence of ESBL-KP in adult ICUs. SHV genotype was more prevalent than TEM type. Strict implementation of basic infection control measures seems to be the most effective means for controlling the spread of ESBL organisms