Evaluation of the chromogenic medium [CPS] in the isolation and identification of urinary tract pathogens

Urine cultures constitute the majority of the workload for a microbiology laboratory with only 20%-30% of urine sample resulting in significant growth. Chromogenic media [CM] are available for urine specimens to enable rapid identification of common pathogens and also has been reported to increase mixed culture detection, reducing unnecessary workup. Chromogenic media offers the potential to lower costs by providing decreased work time, storage space and identification costs. The present study focused on evaluation of the chromogenic medium [CPS] for the diagnosis of UTI in comparison with CLED as a conventional medium. Over the period of January to July 2014, fifty urine samples with >/=100 pus cells /HPF were examined. CPS and CLED media were used for direct inoculation in addition to conventional biochemical reactions and/or API as needed. In comparison with CLED, CPS showed a sensitivity of 93.5%, specificity of 100%, positive predictive value of 100%, negative predictive value of 57.1% and total agreement of 94%. The sensitivity of CPS for E. coli was 95%, for KESC was 75%, for Proteeae was 100% and for Enterococcus was 100%. The specificity of CPS for detection of E. coli was 100%, for KESC was 100%, for Proteeae was 97.9% and for Enterococcus was 100%. CPS proved to be a rapid, cost-effective diagnostic method for urinary tract infections. Therefore, CPS can replace the standard primary plating media used in routine diagnosis of urinary tract infection

Comparison of common detection methods for chlamydia trachomatis and genital mycoplasmas in cervical infection

Genitourinary infections are caused by a large number of diverse microbial agents, in many women with cervicitis, these agents are not detected, even when highly sensitive diagnostic tests are performed. Less urbanized communities have a proportionally higher incidence of urethritis and cervicitis, caused by Chlamydia trachomatic [C. trachomatis]. In addition, mycoplasmas commonly colonize the genital tracts of men and women, and the ability of some species to cause non-gonococcal urethritis and cervicitis has been well established. To detect the prevalence of C. trachomatis, M. hominis and U. urealyticum in cases of cervicitis and to compare different laboratory methods for the diagnosis of these organisms. A total of 50 women suffering from cervicitis were enrolled in this work. To determine the causative agents, PCR, detection of mycoplasmas [Using Mycoplasma IST2 kit] and direct immunofluorescence assay for Chlamydia trachomatis were used. U. urealyticum was isolated from 18 cases [36%], while M. hominis was isolated only from 2 cases [4%]. Besides, 10 cases [20%] were infected by both organisms. U. urealyticum was detected in 5 cases [10%] by multiplex PCR and in 8 cases [16%] by monoplex PCR. M. hominis was detected in 10 cases [20%] both by multiplex as well as by monoplex PCR. C. trachomatis was detected in 3 samples with counts of 16.760, 28.2 and 10 DNA copies/ml using Real Time PCR. However, it was not detected by direct immunofluorescence assay in any of the samples. Mycoplasma IST2 culture was more sensitive for the detection of genital mycoplasmas and Real Time PCR was a better diagnostic test for the detection of C. trachomatis

Comparison of different methods to diagnose pneumocystis jiroveci pneumonia in children with haematological malignancies

Giemsa stain and PCR [single and nested PCR] were compared to a direct immunofluorescence assay [IFA] for the detection of Pneumocystis jiroveci in immuno-compromised patients with haematological malignancies, suspected of having P. jiroveci pneumonia. A total of 50 specimens [3 bronchoalveolar lavages [BAL], 16 sputum samples and 31 nasopharyngeal aspirate samples] were obtained from the Paediatric Oncology Unit of Kasr El-Aini Oncology Centre, Faculty of Medicine, Cairo University. Direct immunofluorescence [the gold standard] could detect 4 positive cases. Giemsa stain could only detect one positive case, being 25% sensitive and 100% specific. Single PCR could detect 3 positive cases, being 75% sensitive and 100% specific. Nested PCR could detect 36 positive cases, being 100% sensitive and 19.2% specific. We conclude that whenever possible, BAL samples should be obtained, for the diagnosis of P. jiroveci pneumonia [PJP]. Diagnosis of PJP should best be performed by IF or single PCR, especially if non-invasive samples are used. Nested PCR is recommended for detection of P. jiroveci in all immunosuppressed asymptomatic patients to identify a group of patients at high risk of developing PJP in the future, for whom proper chemoprophylaxis against P. jiroveci may be beneficial

Virulence factors and susceptibility patterns of candida species isolated from patients with obstructive uropathy and bladder cancer

Candiduria is a common and high risk event in patients with uropathies and cancer. In this study we investigated the distribution of 3 virulence factors namely: biofilm formation [BF], secreted aspartyl proteinase [SAP] and phospholipase activity [PLA] among different Candida species isolated from inpatients with candiduria. The susceptibility patterns of Candida isolates to antifungal agents, including the new voriconazole, were evaluated in vitro and the association of these virulence factors with resistance was studied. Urine specimens from 250 patients divided into 3 groups were examined: Group1 [n=50] cancer bladder; Group2 [n=100] obstructive uropathy and Group 3 [n=100] simple recurrent urinary tract infection [UTI]. Candida isolates were identified by CHROM-agar, and by Candifast Es Twin test. Susceptibility testing to antifungal agents was evaluated by disc diffusion test using fluconazole [FCZ] 30microg discs and E test strips for Minimum inhibitory concentration [MIC] determination of FCZ, voriconazole [VCZ] and Amphotericin B [AMB]. Assessment of BF was performed by tube and spectrophotometric plate adherence methods and quantitated by crystal violet staining and XTT reduction assays. PLA was screened using Sabouraud egg yolk agar and SAP was detected using bovine serum albumin agar [BSA]. The overall prevalence of candiduria was 24% with highest incidence among obstructive uropathy patients [67.2%]. Isolation rate of Candida [C]. nonalbicans species [C. tropicalis ,C. krusei and C. glabrata] was significantly higher than C. albicans [73.1% versus 26.8%; p256microg/ml]. Voriconazole, the new triazole antifungal agent, was active against all isolated Candida species with a sensitivity rate of 82%-100% and low MIC values [0.064-1microg/ml] except in C. glabrata species [22%]. All isolated Candida species were more sensitive to VCZ compared to FCZ; particularly C. krusei isolates [90% versus 9%]. AMB remained to be an effective drug with absolute sensitivity and low MIC