GeneXpert MTB/RIF Testing in the Management of Patients with Active Tuberculosis; A Real Life Experience from Saudi Arabia.

BACKGROUND: GeneXpert MTB/RIF is a real-time PCR assay with established diagnostic performance in pulmonary and extra-pulmonary forms of tuberculosis. The aim of this study was to assess the contribution of GeneXpert MTB/RIF assay to the management of patients with any form of active tuberculosis in a single large tertiary center in Saudi Arabia, with a special focus on the impact on time to start of antituberculous therapy compared with Ziehl-Neelsen (ZN) smears and mycobacterial cultures. MATERIALS AND METHODS: Clinical, radiological and laboratory records for all patients who were commenced on antituberculous therapy between March 2011 and February 2013 were retrospectively reviewed. RESULTS: A total of 140 patients were included, 38.6% of which had pulmonary tuberculosis. GeneXpert MTB/RIF was requested for only 39.2% of patients and was the only reason for starting antituberculous therapy for only 12.1%. The median time to a positive GeneXpert MTB/RIF result was 0 days (IQR 3) compared with 0 day (IQR 1) for smear microscopy (P > 0.999) and 22 days (IQR 21) for mycobacterial cultures (P < 0.001). No patients discontinued antituberculous therapy because of a negative GeneXpert MTB/RIF result. CONCLUSIONS: In a setting wherein physicians are highly experienced in the diagnosis and treatment of tuberculosis, GeneXpert MTB/RIF was remarkably under-utilized and had only a limited impact on decisions related to starting or stopping antituberculous therapy. Cost-effectiveness and clinical utility of routine testing of all smear-negative clinical samples submitted for tuberculosis investigations by GeneXpert MTB/RIF warrant further study.

Prevalence of colistin and tigecycline resistance in Acinetobacter baumannii clinical isolates from 2 hospitals in Riyadh Region over a 2-year period.

OBJECTIVE: To describe the rates and patterns of colistin and tigecycline resistance among Acinetobacter baumannii (A. baumannii) isolates from clinical specimens from 2 major hospitals in Riyadh Region over a 2-year period. METHODS: This is a retrospective review of records of all clinical isolates of A. baumannii from the departments of microbiology at King Faisal Specialist Hospital and Research Center (KFSHRC) and Prince Sultan Military Medical City (PSMMC), Riyadh, Kingdom of Saudi Arabia for the period from January 2010 to December 2011. RESULTS: Records for 1307 Acinetobacter species isolates were identified. The overall tigecycline resistance rates were 9.7% and colistin 1.8%. Among Acinetobacter isolates from KFSHRC, tigecycline resistance rate increased from 10.4% in 2010 to 20.5% in 2011. Colistin resistance increased over the same period from 2.6% to 4.7%. No Acinetobacter isolates from PSMMC were reported to be colistin resistant, while tigecycline resistance rates increased from 1.3% in 2010 to 6.6% in 2011. In KFSHRC, resistance to tigecycline was reported significantly more in isolates from samples that originated in the intensive care units, whereas in PSMMC tigecycline resistance was reported exclusively from clinical areas other than intensive care. No temporal clustering of Acinetobacter isolates was apparent in either hospital over the study period. CONCLUSION: Tigecycline and colistin resistance were reported from a considerable proportion of Acinetobacter clinical isolates from the study hospitals over a 2-year period.

Evaluation of direct detection of Mycobacterium tuberculosis complex in respiratory and non-respiratory clinical specimens using the Cepheid Gene Xpert® system.

OBJECTIVE: To compare the sensitivity and specificity of Cepheid Gene Xpert®, MTB/RIF assay for direct detection of Mycobacterium tuberculosis complex (MTBC) and rifampin (RIF) resistance with conventional methods in respiratory and non-respiratory clinical specimens. METHODS: We used a cross sectional design to evaluate a diagnostic test at the TB Section of the Division of Microbiology, Central Military Laboratory and Blood Bank, Prince Sultan Military Medical City, Riyadh, Kingdom of Saudi Arabia from October 2011 to January 2012. The detection of MTBC and RIF resistance using the Xpert® MTB/RIF assay was assessed in 239 (172 respiratory, and 67 non respiratory) specimens received from 234 patients suspected of TB, and compared with conventional smear microscopy and culture methods. RESULTS: Out of the 239 specimens investigated, 62 (25.9%) were MTBC positive by culture, while 59 (24.6%) were positive by Xpert® assay. Three samples showed false negative Xpert® results. Compared with the culture, the Xpert® assay achieved 95.4% (95% CI: 89-100%) sensitivity, and 100% (95% CI: 93.6-100%) specificity for respiratory samples, while the sensitivity for non-respiratory specimens was 94.4% (95% CI: 90.2-98.5), and the specificity for non-respiratory specimens was 100% (95% CI: 95.8-100%). Overall, a 95.2% (95% CI: 87.6-100) sensitivity, and 100% (95% CI: 92.4-100%) specificity, was observed for the Xpert® MTB/RIF assay compared with conventional methods for MTBC detection. CONCLUSION: The gene Xpert® MTB/RIF assay is a helpful tool for the detection of MTBC and RIF resistance in respiratory and non-respiratory clinical samples with a high sensitivity and specificity within 2 hours as compared with conventional methods, which took a much longer time.

Community acquired Klebsiella pneumoniae, K1 serotype. Invasive liver abscess with bacteremia and endophthalmitis.

A community-acquired syndrome of cryptogenic invasive Klebsiella pneumoniae (K. pneumoniae) liver abscess (CIKPLA) has been emerging worldwide over the past 3 decades, particularly in Taiwan and Korea. It is caused by highly virulent hypermucoviscous, rmpA positive K. pneumoniae serotype K1. This condition occurs in predominantly diabetic persons with no underlying hepatobiliary disease. Metastatic infections of the brain, meninges, lungs, pleura, bones, soft tissues, and eyes are unique features of this syndrome. We report a laboratory-confirmed regulator of mucoid phenotype (rmp)A-positive, K1 serotype K. pneumoniae from Saudi Arabia in 2 diabetic native Saudis presenting with community acquired, invasive liver abscess complicated in one by endogenous endophthalmitis. Following medical and surgical treatment, both patients were cured from liver abscesses, however there was unilateral permanent visual loss in one patient.

Antimicrobial-resistant bacteria in a general intensive care unit in Saudi Arabia.

OBJECTIVE: To assess the prevalence of multi-drug resistant (MDR) bacteria causing infections in patients at the intensive care units (ICUs) of Riyadh Military Hospital (RMH), as well as their antimicrobial resistance patterns for one year. METHODS: A retrospective, cohort investigation was performed. Laboratory records from January to December 2009 were studied for the prevalence of MDR Gram-negative and Gram-positive bacteria and their antimicrobial resistance in ICU patients from RMH, Riyadh, Kingdom of Saudi Arabia. RESULTS: A total of 1210 isolates were collected from various specimens such as: respiratory (469), blood (400), wound/tissue (235), urinary (56), nasal swabs (35), and cerebro-spinal fluid (15). Regardless of the specimen, there was a high rate of nosocomial MDR organisms isolated from patients enrolled in the General ICU (GICU) in Riyadh. Acinetobacter baumannii (A. baumannii) comprised 40.9%, Klebsiella pneumonia (K. pneumonia) - 19.4%, while Pseudomonas aeruginosa (P. aeruginosa) formed 16.3% of these isolates. CONCLUSION: The P. aeruginosa, A. baumannii, K. pneumoniae, Escherichia coli, Staphylococcus aureus (methycillin sensitive and methycillin resistant), and Staphylococccus coagulase negative are the most common isolates recovered from clinical specimens in the GICU of RMH. Respiratory tract specimens represented nearly 39% of all the specimens collected in the ICU. The most common MDR organisms isolated in this unit were A. baumannii, and K. pneumoniae.

Prevalence of extended-spectrum beta-lactamases among Enterobacteriaceae isolated from blood culture in a tertiary care hospital.

OBJECTIVE: To determine the prevalence of extended spectrum beta-lactamase among Enterobacteriaceae isolated from blood culture in a tertiary care hospital. METHODS: We carried out this study at the Armed Forces Hospital, Riyadh, Kingdom of Saudi Arabia during the period between January 2003-December 2004. We tested a total of 601 isolates of the family Enterobacteriaceae from blood culture for the prevalence of extended spectrum beta-lactamase (ESBL) production by the standardized disc diffusion method and confirmed by the ESBL E test strips. RESULTS: Ninety-five (15.8%) of the isolates were ESBL producers. Among these, 48.4% were Klebsiella pneumoniae (K. pneumoniae) followed by 15.8% of both Escherichia coli (E. coli) and Enterobacter cloacae (Ent. cloacae). Other isolates produced ESBL in low numbers. CONCLUSION: Klebsiella pneumoniae produced ESBL in significant numbers. Extended spectrum beta-lactamase gram-negative bacilli present significant diagnostic and therapeutic challenges to the management of infections due to these organisms. Microbiology laboratories should start reporting ESBL producing Enterobacteriaceae organism due to their importance in respect to antibiotic therapy and infection control aspects.