ABSTRACT
BACKGROUND: The Abbott RealTime MTB is an assay for the detection of Mycobacterium tuberculosis (MTB) complex DNA from respiratory specimens in combination with the Abbott RealTime RIF/INH assay for the detection of genetic resistance markers for isoniazid (INH) and rifampicin (RIF) from MTB positive isolates. Hence, this study aimed to evaluate the performance of the Abbott RealTime MTB and RIF/INH assays. METHODS: A cross-sectional study was conducted on 289 study subjects presumptive to have pulmonary tuberculosis at Nigist Eleni Mohammed Memorial Hospital, South Ethiopia from April 2017 to June 2018. Two morning expectorated sputum specimens were collected from each study participant. One sample was tested directly by Xpert MTB/RIF assay at Nigist Eleni Mohammed Memorial Hospital and the other sample was used for smear microscopy, TB culture, Abbott RealTime MTB, and Abbott RealTime INH/RIF assays at International Clinical Laboratories, Addis Ababa, Ethiopia. The diagnostic performance of the Abbott RealTime MTB and INH/RIF assays were calculated against MGIT liquid culture and phenotypic drug susceptibility testing (DST) as the gold standard. RESULTS: For the detection of MTB the Abbott RealTime MTB assay exhibited sensitivity 92.4% (95% CI 83.6-96.9), specificity 95.4% (95% CI 91.1-97.7), PPV 89.0% (95% CI 79.7-94.5) and NPV 96.9% (95% CI 93.0-98.7). For the detection of RIF resistance MTB, Abbott RealTime MTB RIF/INH concurred with phenotypic DST and Xpert MTB/RIF, while for the detection of INH resistance MTB, the sensitivity, specificity, PPV and NPV of the Abbott MTB RIF/INH assay was 84.2% (95% CI 60.4-96.6), 100% (95% CI 89.7-100), 100% and 91.9% (95% CI 80.0-96.9), respectively. CONCLUSIONS: The Abbott RTMTB and RIF/INH assays revealed high sensitivity and specificity in MTB diagnosis and provided reliable INH and RIF resistance profiles. This assay has a similar diagnostic performance to the Xpert MTB/RIF assay with the advantages of high-throughput.
Subject(s)
Mycobacterium tuberculosis/isolation & purification , Sputum/microbiology , Tuberculosis, Pulmonary/diagnosis , Adult , Cross-Sectional Studies , Diagnostic Tests, Routine , Humans , Microbial Sensitivity TestsABSTRACT
BACKGROUND: Urinary tract infection (UTIs) is a significant health problem in diabetic patients because of the multiple effects of this disease on the urinary tract and host immune system. Complicated UTIs occur most commonly in patients with abnormal genitourinary tract. Proper investigation and prompt treatment are needed to prevent morbidity and serious life threatening condition associated with UTI and diabetes co-morbidities. OBJECTIVE: To determine common uropathogens and antibiotic susceptibility patterns with associated risk factors among adult diabetic patients attending at St. Paul Specialized Hospital Millennium Medical College, Addis Ababa, Ethiopia. METHODS: A hospital based, cross-sectional study was conducted from April-July 2015. A total of 248 diabetic patients with asymptomatic and symptomatic UTI were investigated for common uropathogens. Clean catch mid-stream urine specimens were collected from each study subjects. Uropathogens were isolated and identified by using conventional standard techniques. Samples were cultured on Blood agar, MacConkey agar and Sabouraud Dextrose Agar. Antibiotic Susceptibility pattern was determined on Mueller-Hinton using Kirby -Bauer disc diffusion method. The collected data and the result of the laboratory were analyzed using SPSS version 20. RESULTS: The overall prevalence of uropathogens among diabetic patients was 56/248(22.6%) of which 21/177(11.9%) and 35/71(49.3%) had asymptomatic and symptomatic UTI respectively. E. coli 13/56(23.2%), Coagulase negative Staphylococci (CONs) 7/56(12.5%), Enterococcus Spp.6/56 (10.7%), Candida albicans 10/56(17.9%) and Non-albicans Candida Spp. 9/56(16.1%) were the commonest isolated uropathogens. In this study uropathogens were significantly associated with being type II diabetes patient and having previous UTI history. Both gram positive and gram negative bacteria showed resistance to most tested antibiotics. Drug resistance to two or more drugs was observed in 81.1% of bacterial isolates. CONCLUSION: High prevalence of uropathogens and increased rate of Multi-drug resistance was shown in this study. Therefore, continued surveillance on uropathogens prevalence and resistance rates is needed to ensure appropriate recommendations for the empirical treatment, develop rational prescription programs and make policy decisions.
Subject(s)
Diabetes Mellitus, Type 2/microbiology , Gram-Negative Bacterial Infections/microbiology , Gram-Positive Bacterial Infections/microbiology , Urinary Tract Infections/microbiology , Adult , Anti-Bacterial Agents/therapeutic use , Cross-Sectional Studies , Diabetes Mellitus, Type 2/complications , Disk Diffusion Antimicrobial Tests , Escherichia coli/drug effects , Escherichia coli/isolation & purification , Ethiopia/epidemiology , Female , Gram-Negative Bacteria/drug effects , Gram-Negative Bacteria/isolation & purification , Gram-Negative Bacterial Infections/epidemiology , Gram-Positive Bacteria/drug effects , Gram-Positive Bacteria/isolation & purification , Gram-Positive Bacterial Infections/epidemiology , Humans , Male , Microbial Sensitivity Tests , Middle Aged , Prevalence , Urinary Tract Infections/epidemiologyABSTRACT
BACKGROUND: Xpert MTB/RIF assay is considered as a great advance over conventional smear and culture in the diagnosis of TB and MDR-TB by simultaneously detecting M.tuberculosis and rifampicin resistance bacilli. However, very little information regarding the performance characteristics of Xpert MTB/RIF assay is available in Ethiopia. Therefore, the purpose of this study was to evaluate the performance of Xpert MTB/RIF assay compared to conventional sputum smear and culture methods for the diagnosis of pulmonary tuberculosis in remote health care facility. METHODS: A paired expectorated sputum samples were obtained from 227 consecutively recruited patients with signs and symptoms suggestive of tuberculosis at Karamara hospital during December 2013 to May 2014. One of the sputum specimen was tested directly by Ziehl-Neelsen staining and Xpert MTB/RIF assay without NALC-NaOH decontamination. The other of pair of sputa specimen was cultured for isolation of TB bacilli by conventional methods. Diagnostic performance of Xpert MTB/RIF assay and AFB smear microscopy were calculated against culture as the gold standard. RESULTS: Overall 25.5% (58/227) samples were positive for Mycobacterium tuberculosis complex (MTBC) by MGIT and/or LJ media of which 36.2% (21/58) and 65.5% (35/58) were positive by AFB smear microscopy and Xpert MTB/RIF respectively. The sensitivity, specificity, as well as the positive and negative predictive value of Xpert MTB/RIF assay were 65.5% (95% CI: 53.3-77.7%), 96.3% (95% CI: 93.4-99.2%), 86.4% (95% CI: 76.2-96.5%), and 88.6% (95% CI: 83.9-93.3%) respectively. Eighteen of 58 (31%) cases that were smear microscopy negative, were positive by Xpert MTB/RIF assay. CONCLUSIONS: Although Xpert MTB/RIF assay demonstrated high sensitivity in detecting MTBC in sputum specimens compared with conventional AFB smear microscopy, it demonstrated suboptimal sensitivity in smear negative patients compared to conventional culture.
