Neisseria meningitidis with H552Y substitution on rpoB gene shows attenuated behavior in vivo: report of a rifampicin-resistant case following chemoprophylaxis.

We present the first Italian reported case of an invasive meningococcal disease with rifampicin-resistance (Rif-R)secondary to chemoprophylaxis. The case is entered in a cluster of two IMDs registered in Tuscany, Italy, in November 2019 caused by two non-differentiable group-C Neisseria meningitidis belonging to ST-11 clonal-complex. The contact case, differently from the index, harbored H552Y mutation on rpoB gene which is known to confer Rif-R putting a high-cost fee on bacterial fitness. The extremely mild clinical presentation in the contact can constitute an in vivo demonstration of the virulence attenuation observed in vitro for H552Ymutants. Clinicians should be aware of the possibility of secondary cases with induced Rif-R and keep a high level of suspicion on contacts who received rifampicin-chemoprophylaxis. Molecular characterization of Rif-R should be performed routinely directly on biological samples and not only on isolates, in order to rapidly detect rare cases of resistance and consequently modify chemoprophylaxis for contacts.

Anterior dislocation in a total knee arthroplasty: A case report and literature review.

Dislocations of a total knee arthroplasty (TKA) are an uncommon injury and only few cases of anterior dislocations have been reported. We report a rare case of anterior dislocation of a 10-year-old posterior stabilized total knee arthroplasty in a 74-year-old woman. The patient was successfully treated by close reduction of the dislocation followed by immobilization in full extension with a long leg cast. Because of a high risk of neurovascular complications, a high index of suspicion for vascular injury must be maintained. For this reason, a proper diagnosis is required and immediate reduction is recommended.