PMC9439645_01
The string test in an isolated colony of Klebsiella pneumoniae from the CSF on an agar plate, which showed hypermucoviscosity with a > 5-mm-long viscous filament.
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On the third day of admission, the CSF culture result was found to be positive, and the pathogen was preliminarily identified as hypermucoviscous K. pneumoniae based on a positive string test (Figure 1).
The virulence genes of three isolates. 1-5 represent rmpA2, iucA, peg-344, iroB, and rmpA, respectively, from the father's stool sample, and 6-10 represent rmpA2, iucA, peg-344, iroB, and rmpA, respectively, from the infant's stool isolate. 11-15 represent rmpA2, iucA, peg-344, iroB, and rmpA, respectively, from the infant's CSF isolate. M represents the marker.
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Virulence gene results show that the isolates from the CSF and stool samples from the infant were positive for peg-344, iroB, and rmpA and negative for rmpA2 and iucA, whereas the isolate from the father's stool was positive for all the five virulence genes (Figure 2).
The capsular types of three isolates were K2. (A and B) represent the isolate from the father's stool. (C and D) represent the isolate from the infant's stool. (E and F) represent the isolate from the infant's CSF. M represents the marker.
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The three K. pneumoniae isolates were all identified as capsular serotype K2 (Figure 3) and ST86.