An UPAB1 derivative, UPAB1p-, that spontaneously loss pAB5 was identified by detection of restored Hcp secretion and isolated via an ELISA.
Compared to wildype UPAB1, UPAB1p- displayed comparable growth in vitro in both rich medium and urine from healthy donors, indicating that less pAB5 did not influence bacterial growth. However, UPAB1p- displayed increased susceptibility to multiple antibiotics.