Isolation of Corynebacterium freneyi from a case of exudative pharyngitis, a close mimicker of Corynebacterium diphtheriae.

Corynebacterium freneyi is a recently described coryneform bacteria. It is only rarely identified from clinical specimens and its pathogenic significance has not been well studied. Here we report the isolation of the species from the throat swab of a patient with suspected diphtheria. The morphology on direct microscopy and culture also closely resembled Corynebacterium diphtheriae, which almost led to misidentification. The prompt clinical and microbiological response suggests a probable pathogenic role. This is the first report of the isolation of this species from an oropharyngeal sample.

Evaluation of performance of direct disk diffusion test from positively flagged blood culture broth: A large scale study from South India.

BACKGROUND: Rapid turnaround time of blood culture reports should be the main motive for a clinical microbiologist for optimal patient care. Categorical agreement (CA) between direct disk diffusion (dDD) and reference disk diffusion (rDD) may vary between laboratories. AIMS AND OBJECTIVES: This study was designed to determine the CA and understand various types of errors associated with antibiotic organism combination, so that caution can be derived while interpreting and reporting dDD results in the earliest meaningful time frame. MATERIALS AND METHODS: In the present study, dDD results were compared to the rDD results from the positive blood culture bottles. CA and various types of errors were evaluated. RESULTS: A total of 965 pathogens and 7106 organism antibiotic combinations were evaluated in this study. Overall, there was a CA of 96% which was extremely satisfactory. The categorical disagreement was found only in 4% of organism antibiotic combinations; majority of which were major error (ME, 2.1%) followed by very ME (1%) and minor error (0.9%). The errors were marginally high for Enterobacteriaceae testing against ß lactam- ß lactamase inhibitor combinations, for Pseudomonas species against aminoglycosides and ciprofloxacin and Staphylococcus species against cefoxitin, one should be vigilant while reporting dDD result of these antibiotic organism combinations. CONCLUSION: dDD is of paramount importance for early institution of targeted therapy and is considered as one of the key stewardship intervention. Our study gives an insight that every laboratory must perform dDD for positively flagged blood culture specimens; the result of which should be confirmed later by performing rDD. One should be vigilant while reporting dDD result of BL BLI for Enterobacteriaceae; aminoglycosides and CF for Pseudomonas species; cefoxitin for Staphylococcus species and HLG for Enterococcus species. Supplementary tests such as MRSA latex should be included when necessary.