PT  - JOURNAL ARTICLE
AU  - Doğan, Eyüp
AU  - Sydow, Katharina
AU  - Heiden, Stefan E.
AU  - Eger, Elias
AU  - Wassilew, Georgi
AU  - Proctor, Richard A.
AU  - Bohnert, Jürgen A.
AU  - Idelevich, Evgeny A.
AU  - Schaufler, Katharina
AU  - Becker, Karsten
TI  - <em>Klebsiella pneumoniae</em> exhibiting a phenotypic hyper-splitting phenomenon including the formation of small colony variants
AID  - 10.1101/2024.01.11.575232
DP  - 2024 Jan 01
TA  - bioRxiv
PG  - 2024.01.11.575232
4099  - http://biorxiv.org/content/early/2024/01/13/2024.01.11.575232.short
4100  - http://biorxiv.org/content/early/2024/01/13/2024.01.11.575232.full
AB  - In this study, we characterized a Klebsiella pneumoniae strain in a patient with shrapnel hip injury, which resulted in multiple phenotypic changes, including the formation of a small colony variant (SCV) phenotype. Although already described since the 1960s, there is little knowledge about SCV phenotypes in Enterobacteriaceae. The formation of SCVs has been recognized as a bacterial strategy to evade host immune responses and compromise the efficacy of antimicrobial therapies, leading to persistent and recurrent courses of infections. In this case, 14 different, clonally identical resisto- and morpho-types were distinguished from the patient’s urine and tissue samples. Whole genome sequencing revealed the K. pneumoniae high-risk clonal lineage belonging to sequence type 147. Subculturing the SCV colonies consistently resulted in the reappearance of the initial SCV phenotype and three stable normal-sized phenotypes with distinct morphological characteristics. Additionally, an increase in resistance was observed over time in isolates that shared the same colony appearance. Our findings highlight the complexity of bacterial behavior by revealing a case of phenotypic “hyper-splitting” in a K. pneumoniae SCV and its potential clinical significance.