Isolation of OXA-48-like carbapenemase-producing Escherichia coli susceptible to piperacillin/tazobactam in a Japanese patient without a history of travel abroad.

Oxacillinase (OXA)-48-like ß-lactamases are the most common carbapenemases in Enterobacterales in certain regions of the world and are being introduced on a regular basis into regions of non-endemicity. Japan has been characterized by low rates of carbapenemase-producing Enterobacterales, and among them, OXA-48-like carbapenemase-producing isolates are extremely rare. Here we describe a Japanese medical worker, without a history of travel abroad, who was diagnosed as having a community-acquired urinary tract infection, and whose urine sample was found to be positive for OXA-48-like carbapenemase-producing Escherichia coli. None of her close contacts had a history of foreign travel, and the same drug-resistant organism was not observed in other patients who had been hospitalized and undergone environmental culture tests in the same medical institution. This isolate was resistant to penicillins, narrow-spectrum cephalosporins, fluoroquinolones, and cefmetazole, but was susceptible to broad-spectrum cephalosporins, piperacillin/tazobactam, and meropenem and displayed reduced susceptibility to imipenem. The modified carbapenem inactivation test supported carbapenemase production, but inhibitor-based synergistic tests yielded negative results of carbapenemase production. Multiplex polymerase chain reaction revealed the presence of the carbapenemase gene (blaOXA-48) blaTEM and AmpC ß-lactamase gene (blaDHA). Singleplex polymerase chain reaction targeting the blaOXA-48 region amplified a product sequencing to nearly the full length (722 bp) and matching 100% with OXA-48. The present case highlights a new concern regarding OXA-48-like carbapenemase-producing Enterobacterales, which remain challenging to detect for clinical laboratories in regions of non-endemicity, and may already be latent in Japan.

Presumptive complicating Clostridium paraputrificum bacteremia as a presenting manifestation in a patient with undiagnosed ulcerative colitis followed by acute colonic pseudo-obstruction.

Clostridium paraputrificum is a member of the commensal flora of the gastrointestinal tract and skin. Despite being linked with cases of severe invasive infection, this organism is an uncommon pathogen in humans. Here, we report a case of undiagnosed ulcerative colitis in which the presentation was one of presumptive complicating C. paraputrificum bacteremia and, later, acute colonic pseudo-obstruction. The patient was an elderly male with prostate cancer who was admitted in a state of shock secondary to suspected septicemia from an abdominal source. Only one of two sets of anaerobic blood cultures were positive for C. paraputrificum. Endoscopic and pathological investigations revealed proctitis consistent with ulcerative colitis. The patient's abdominal manifestations worsened, and abdominal imaging demonstrated de novo massive colonic dilatation without any apparent mechanical obstruction. We speculated that C. paraputrificum bacteremia caused by undiagnosed ulcerative colitis had created ideal conditions for acute colonic pseudo-obstruction. This case demonstrates that C. paraputrificum bacteremia can be associated with latent severe gastrointestinal pathologies, indicating the need to investigate any abdominal source of infection, even if only a single blood culture is positive.