Enterobacter nimipressuralis as a cause of pseudobacteremia

The microbiologic culture monitoring system of sterile body fluids revealed on an episode of Enterobacter cloacae and Enterobacter amnigenus in blood culture results on the same day; the antibiotic sensitivity and MIC were nearly the same for both species. First patient was a healthy woman with postmenopausal syndrome, while second patient with herpes zoster. Both patients had febrile sensations without signs of bacteremia. E. amnigenus was also cultured from the unused package of salined cotton in the container through epidemiologic investigation. The cultured Enterobacter species were all identified as E. nimipressuralis through hsp60 gene sequencing and infrequent-restriction-site PCR (IRS-PCR).When an unusual microorganisms such as E. nimipressuralis is isolated from blood of a patient with no clinical signs of sepsis, a pseudobacteremia should be suspected. When the antibiogram and MIC test results of bacterial cultures from two or more patients are nearly the same, although the species involved may appear different, it may be necessary to prove that they are the same species through molecular methods. The microbiologic cultures monitoring system will probably help to detect pseudobacteremia and other pseudo infections through reliable and fast identification.Chosun University Hospital, Gwang-ju, Korea, is a 650-bed, tertiary care teaching hospital. Every day in our hospital, an infectious disease specialist monitors all the results of the hospital's microbiologic cultures from sterile body fluids such as blood, cerebrospinal fluid (CSF), pleural fluid, ascites, joint fluid and localized fluid collection using a computerized monitoring system. This monitoring system revealed an episode of Enterobacter nimipressuralis pseudobacteremia caused by contaminated saline cotton during the preparation of blood culture samples. Here we describe two cases of Enterobacter species pseudobacteremia.A 54-year-old female patient presented with myalgia and febrile sensation to