Bacteriophage-Based Latex Agglutination Test for Rapid Identification of Staphylococcus aureus

Abstract

e Rapid diagnosis is essential for the management of Staphylococcus aureus infections. A host recognition protein from S. aureus bacteriophage phiSLT was recombinantly produced and used to coat streptavidin latex beads to develop a latex agglutination test (LAT). The diagnostic accuracy of this bacteriophage-based test was compared with that of a conventional LAT, Pastorex StaphPlus, by investigating a clinical collection of 86 S. aureus isolates and 128 coagulase-negative staphylococci (CoNS) from deep tissue infections. All of the clinical S. aureus isolates were correctly identified by the bacteriophage-based test. While most of the CoNS were correctly identified as non-S. aureus isolates, 7.9% of the CoNS caused agglutination. Thus, the sensitivity of the bacteriophage-based LAT for identification of S. aureus among clinical isolates was 100%, its specificity was 92.1%, its positive predictive value (PPV) was 89.6%, and its negative predictive value (NPV) was 100%. The sensitivity, specificity, PPV, and NPV of the Pastorex LAT for the identification of S. aureus were 100%, 99.2%, 98.9%, and 100%, respectively. Among the additionally tested 35 S. aureus and 91 non-S. aureus staphylococcal reference and type strains, 1 isolate was false negative by each system; 13 and 8 isolates were false positive by the bacteriophage-based and Pastorex LATs, respectively. The ability of the phiSLT protein to detect S. aureus was dependent on the presence of wall teichoic acid (WTA) and corresponded to the production of ribitol phosphate WTA, which is found in most S. aureus clones but only a small minority of CoNS. Bacteriophage-based LAT identification is a promising strategy for rapid pathogen identification. Finding more specific bacteriophage proteins would increase the specificity of this novel diagnostic approach.

Molecular identification of Staphylococcus aureus isolated from clinical samples by specific PCR assay targeting the signal transduction gene

“…Several Staphylococcus species, such as Staphylococcus epidermis (S. epidermis), Staphylococcus haemolyticus (S. haemolyticus), and the coagulase negative species, have been isolated from ewe's milk and were found to produce one or several staphylococcus enterotoxins [2] and consequently there is a need for methods to specifically discriminate S. aureus from other staphylococci and non-staphylococci as quickly as possible. Conventional identification methods and novel assays based on immunofluorescence probe, DNA microarray, surface enhanced laser desorption and ionization time of flight mass spectrometry, and whole-cell SELEX methods are time-consuming and may yield false-positive or false-negative results, and misclassifications with automated susceptibility testing systems or commercially available latex agglutination kits have been reported recently [4][5][6][7][8][9][10][11][12][13] .…”

Rapid Clinical Screening of Burkholderia pseudomallei Colonies by a Bacteriophage Tail Fiber-Based Latex Agglutination Assay

“…Similarly, the field evaluation of 94TF-LAA produced 26 false positive results, including A. baumannii. Cross-reactivity has been observed before with phage-based LAAs, especially when identifying between species within the same genera (44). Misidentification of B. pseudomallei as Acinetobacter spp.…”

Rapid Waterborne Pathogen Detection with Mobile Electronics

“…After the filtration process, 99.5% of liquid is removed from the original water sample, yielding a 200-fold enrichment in sample concentration and accelerated immunochemistry reaction rate. Traditionally, immunoagglutination is only used in a qualitative test; however, together with the narrow beam technique, immunoagglutination offers a simple, generally applicable, and non-hazardous method for fast and bacterium-specific quantitative detection [ 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 ]. More importantly, the agglutination reaction is a one-step reaction method mediated by specific reactions between antibodies immobilized on microbeads and antigens in the sample, requiring no further washing steps prior to detection.…”