Baha Abdalhamid

Use of rapid influenza diagnostic tests under field conditions as a screening tool during an outbreak of the 2009 novel influenza virus: Practical considerations

BACKGROUND Rapid influenza diagnostic tests (RIDTs) are used in various settings as a first-line screen of patient specimens. During the initial outbreak of the 2009 novel influenza A/H1N1 virus, the Nebraska Public Health Laboratory (NPHL) adopted a testing algorithm, attempting to maximize the usefulness of RIDTs. However, it became apparent that a high percentage of the positive specimens received from off-site facilities were negative for influenza viruses by the confirmatory test, the Luminex xTAG Respiratory Viral Panel (RVP) molecular assay. OBJECTIVES To explore the cause of discrepancies between RIDTs results obtained from on-site facility testing versus confirmatory testing performed at NPHL. STUDY DESIGN Specimens (n=336) tested with RIDTs at off-site facilities and screened for high-probability of containing H1N1 were sent to the NPHL for confirmatory testing by RVP. RESULTS Of 336 specimens analyzed, 104 were negative for influenza A or B by both RIDT and RVP; 127 were positive by both tests; 102 were positive by RIDT only; and 3 were positive by RVP only. Using the RVP assay as the gold standard, overall RIDT characteristics in this screened population were: sensitivity=97.7% (95%CI: 92.5, 99.3); specificity=48.1% (95%CI: 40.4, 55.8); positive predictive value=54.3% (95%CI: 47.0, 61.4); and negative predicative value=97.1% (95%CI: 90.6, 99.1). CONCLUSIONS The results show that the confirmation of RIDT-positive results varied widely by testing site. Possible explanations for the discrepancies in performance characteristics include testing a narrowly defined sample population, test facility characteristics, facility work load, and seasonal timing.

Molecular characterization of extended-spectrum beta-lactamase producing Enterobacteriaceae in a Saudi Arabian tertiary hospital

INTRODUCTION The aim of this study was to determine the prevalence of extended-spectrum beta-lactamase (ESBL) producing Escherichia coli (E. coli), Klebsiella pneumoniae (K. pneumoniae), and Proteus mirabilis (P. mirabilis). In addition, different methods for detection of these enzymes, including the newly introduced CHROMagar ESBL, were evaluated. METHODOLOGY A total of 382 Enterobacteriaceae clinical isolates were obtained from King Fahad Specialist Hospital - Dammam, during 2011 and screened for production of ESBL using advanced expert system of Vitek 2, CHROMagar and ESBL-E-strips. PCR assay was used to detect blaTEM, blaSHV, and blaCTX-M genes. Susceptibility to a panel of antibiotics was determined. RESULTS The overall proportion of ESBL-producing enterobacterial isolates was 30.6%, which was higher in E. coli (35.8%) than in K. pneumoniae (25.7%). ESBL genotypes showed remarkable increase in the CTX-M (97.4%) compared to SHV (23.1%). The predominant ESBL was CTX-M- 15 (92.1 %). No TEM ESBL was detected in this study. The Vitek2 showed the highest sensitivity (100%), and the CHROMagar had the lowest specificity (97.3%) compared to the molecular method. All isolates were susceptible to imipenem and meropenem. CONCLUSIONS This study confirms a high level of blaCTX-M positive ESBL isolates are circulating in the Eastern Province of Saudi Arabia. The trend of a multidrug-resistant profile associated with the recovery of the blaCTX-M gene is alarming.

Strongyloides stercoralis infection in kidney transplant recipients.

Strongyloides stercoralis is an uncommon infection in Saudi Arabia. It can establish latency and cause an autoinfection in humans that lasts for years. The infection can get reactivated during immunosuppression and can result in a life-threatening Strongyloides hyperinfection syndrome. We present three cases of renal transplant recipients who developed Strongyloides infection following transplantation. A bronchoalveolar lavage specimen, a duodenal biopsy and/or a stool specimen from these patients revealed evidence of S. stercoralis larvae. The first two patients received kidneys from the same deceased donor, a native of Bangladesh, an area that is highly endemic for S. stercoralis. The data suggest that the first two cases might be donor derived. High-risk donors and recipients should be screened for Strongyloides infection to initiate treatment before transplantation thus reducing morbidity and mortality.

Prevalence of digestive tract colonization of carbapenem-resistant Acinetobacter baumannii in hospitals in Saudi Arabia.

Carbapenem-resistant Acinetobacter baumannii is a major health problem worldwide, especially in intensive care units (ICUs). This study aimed to detect the prevalence of A. baumannii colonization of the gastrointestinal tract of patients admitted to the ICU in two hospitals in Saudi Arabia. In addition, it aimed to characterize the molecular mechanisms of carbapenem resistance in these isolates. From January to June 2014, 565 rectal swab specimens were screened for Acinetobacer strains and carbapenem resistance using CHROMagar Acinetobacter and CHROMagar KPC agar plates, respectively. Organism identification and susceptibility were detected using the Vitek 2 system. A total of 47 Acinetobacter spp. were detected, and 35 were resistant to carbapenem, making the prevalence of Acinetobacter spp. 8.3% (47/565) and carbapenem resistance (6.2%, 35/565). The 47 strains showed remarkable clonal diversity as revealed by PFGE. Using PCR, OXA-51, a chromosomal marker for A. baumannii, was detected in 46 strains. OXA-23 β-lactamase was detected in all 35 carbapenem-resistant A. baumannii. No IMP, VIM, SPM, SIM, GIM, KPC or NDM β-lactamases were detected in these isolates. Thus, OXA-23 was the main mechanism of carbapenem resistance in these isolates. To the best of our knowledge, this is the first study to detect the prevalence of Acinetobacter colonization in the digestive tract of ICU patients in Saudi Arabia. This study revealed the importance of having well-established protocols for early identification of these multidrug-resistant organisms, optimizing infection-control strategies and having active surveillance studies to reduce morbidity, mortality and cost.

Utilization of the QuantiFERON-TB Gold Test in a Two-Step Process with the Tuberculin Skin Test To Evaluate Health Care Workers for Latent Tuberculosis

ABSTRACT A cost analysis of combining a tuberculin skin test (TST) and the QuantiFERON-TB Gold test (QFT-GT) to detect latent tuberculosis in newly hired health care workers was performed. An approximately 50% reduction in the cost of additional care was realized when workers with positive TST results were subsequently screened using the QFT-GT.

Acinetobacter baumannii Septicemia in a Recipient of an Allogeneic Hematopoietic Stem Cell Transplantation

Acinetobacter baumannii is a gram-negative, nonfermentative coccobacillus that causes infections in immunocompromised and chronically ill patients and is associated with multidrug resistance. Two days before receiving her nonmyeloablative stem cell allograft, a patient with acute myeloid leukemia developed Acinetobacter baumannii bacteremia that caused septic shock which was successfully treated with imipenem and removal of the central venous catheter. To our knowledge, this is the first report of Acinetobacter baumannii septicemia in a hematopietic stem cell transplantation recipient.

Expression of cytomegalovirus in glioblastoma multiforme: Myth or reality?

Abstract A role for human cytomegalovirus (HCMV) in the pathogenesis of glioblastoma multiforme (GBM) was proposed more than a decade ago and has since generated a considerable debate as a possible therapeutic target. We investigate the presence of HCMV in the specimens of patients with GBM treated in our centre. This is a retrospective cohort study to investigate the presence of HCMV by routine immunohistochemical stains and polymerase chain reaction (PCR)-based molecular analysis on formalin-fixed-paraffin-embedded tissue of all patients with GBM treated in our hospital in 2009–2013 (5 years). The evaluation of positivity by immunohistochemistry (IHC) was semi-quantitative. The molecular analysis was performed by extracting the tumour DNA from representative paraffin-embedded tissue blocks and amplified for detection by a sensitive real time PCR (RT-PCR) CMV assay. During the study period, we treated 45 patients with GBM; however, adequate pathology tissue materials were available only for 32 patients. All the pathology material was reviewed and the diagnosis was confirmed. All the cases were found to be negative for CMV expression by our IHC and RT-PCR CMV assay. Our study has shown no expression of CMV in GBM. Our results were similar to other recent reports that concluded insufficient evidence to recommend routine testing for CMV in GBM or treatment as an add-on therapy.

Chryseobacterium gleum pneumonia in an infant with nephrotic syndrome.

Highlights • Chryseobacterium gleum is ubiquitously distributed in the environment.• It can cause pneumonia in patients with underlying disease such as nephrotic syndrome especially with medical device use.• The treatment of Chryseobacterium is challenging; the patient we presented was treated with levofloxacin.

Prevalence study of plasmid-mediated AmpC β-lactamases in Enterobacteriaceae lacking inducible ampC from Saudi hospitals

Purpose. Enterobacteriaceae encoding plasmid‐mediated AmpC (pAmpC) &bgr;‐lactamases confer resistance to the third generation cephalosporins. pAmpC association with extended spectrum &bgr;‐lactamases (ESBLs), plasmid‐mediated quinolone resistance (PMQR) and aminoglycoside modifying enzymes (AMEs) is well documented. There are limited data regarding the epidemiology and clinical significance of pAmpC in Saudi Arabia. This study aimed to determine the prevalence of pAmpC and its coexistence with ESBLs, PMQR and AMEs in Escherichia coli, Klebsiella pneumoniae and Proteus mirabilis isolates in Saudi hospitals from January to December 2015. Methodology. The VITEK 2 system was used for organism identification and susceptibility testing. PCR and sequencing were used to detect pAmpC, ESBL, AME and PMQR genes. Results. Out of 3625 isolates of E. coli, K. pneumoniae and P. mirabilis, 200 cefoxitin‐resistant isolates were identified, making the prevalence of cefoxitin resistance 5.5% (200/3625). CMY‐2 and DHA were detected in 24 and 12 isolates, respectively. The prevalence of pAmpC was 1% (36/3625). In several isolates, pAmpC &bgr;‐lactamases were associated with PMQR genes including aac(6’)‐Ib‐cr and qnrB and/or with AMEs including aacA4, aacC2, aadA1, aphA6, armA and rmtB genes. No ESBLs were detected in pAmpC &bgr;‐lactamase‐harbouring isolates. Conclusions. To our knowledge, this is the first study determining the prevalence of pAmpC &bgr;‐lactamases and their association with PMQR and/or AME genes in Saudi Arabia and the Gulf States. CMY‐2 is the most prevalent pAmpC &bgr;‐lactamase in this study. These data emphasize the importance of surveillance studies and implementation of antimicrobial stewardship programmes to reduce infections caused by such resistant organisms.

Rates of gastrointestinal tract colonization of carbapenem-resistant Enterobacteriaceae and Pseudomonas aeruginosa in hospitals in Saudi Arabia

Carbapenem-resistant Enterobacteriaceae (CRE) and carbapenem-resistant Pseudomonas aeruginosa (CRPAE) are globally a major medical issue, especially in intensive care units. The digestive tract is the main reservoir for these isolates; therefore, rectal swab surveillance is highly recommended. The purpose of this study was to detect the prevalence of gastrointestinal tract colonization of CRE and CRPAE in patients admitted to intensive care units in Saudi Arabia. This project also aimed to characterize carbapenem-hydrolyzing enzyme production in these isolates. From February to May 2015, 200 rectal swab specimens were screened by CHROMagar KPC. Organism identification and susceptibility testing were performed using the Vitek 2 system. One CRE and 13 CRPAE strains were identified, for a prevalence of 0.5% (1/200) and 6.5% (13/200) respectively. Strains showed high genetic diversity using enterobacterial repetitive intergenic consensus sequence-based PCR. NDM type and VIM type were detected by PCR in four and one CRPAE isolates respectively. ampC overexpression was detected in eight CRPAE isolates using Mueller-Hinton agar containing 1000 μg/mL cloxacillin. CTX-M-15 type was detected in 1 CRE by PCR. The prevalence of CRE strain colonization was lower than that of CRPAE isolates. The detection of NDM and VIM in the colonizing CRPAE strains is a major infection control concern. To our knowledge, this is the first study in Saudi Arabia and the gulf region focusing on digestive tract colonization of CRE and CRPAE organisms and characterizing the mechanisms of carbapenem resistance.