Isolation of three distinct carbapenemase-producing Gram-negative bacteria from a Vietnamese medical tourist.

Carbapenem-resistant Klebsiella pneumoniae and Escherichia coli, multidrug-resistant Pseudomonas aeruginosa and vancomycin-resistant Enterococcus faecium were isolated from a single patient. The patient came to Japan for advanced medical treatment after having undergone laparoscopic cholecystectomy and hospitalization in Vietnam. Whole-genome sequence analysis revealed that K. pneumoniae harbored blaOXA-48 that was found on a Col156 -type small plasmid, E. coli harbored blaNDM-5 and P. aeruginosa harbored both blaNDM-1 and 16S rRNA methyltransferase (rmtB). To the best of our knowledge, this is the first report of detection of K. pneumoniae harboring blaOXA-48 on a Col156-type small plasmid in the world and P. aeruginosa coharboring genes encoding NDM-1 and RmtB in Japan.

A case of falciparum malaria: Acute hearing loss as the initial symptom.

A 49-year-old healthy woman, who returned from Burkina Faso, visited an ear, nose, and throat clinic with complaints of left hearing loss, tinnitus, and dizziness. Pure tone audiometry demonstrated bilateral mild sensorineural hearing loss. Three days later, she was transported in an ambulance to a general hospital due to high fever and disturbance of consciousness. Plasmodium falciparum was found in the peripheral blood smear. After diagnosing severe falciparum malaria with cerebral involvement, quinine hydrochloride, clindamycin, and artemether/lumefantrine were administered. After recovery of consciousness, she was followed up at our department with bilateral hearing loss. After taking prednisolone for 10 days, there was improvement to normal hearing level. Furthermore, no neurologic sequelae were observed. In this case, acute sensorineural hearing loss occurred before administration of the antimalarial drug. Therefore, hearing loss was not drug-induced, but was caused by the malaria itself. In patients with acute hearing loss and who have history of travel to tropical regions, physicians should include malaria and other causes of acute deafness in the differential diagnoses.

Diagnostic usefulness of ribosomal protein l7/l12 for pneumococcal pneumonia in a mouse model.

The capsular antigen detection (CAD) kit is widely used in clinics to detect Streptococcus pneumoniae infection from urine, because it is rapid, convenient, and effective. However, there are several disadvantages, including false-positive results in children colonized with S. pneumoniae and prolonged positive readings even after the bacteria have been cleared. RP-L7/L12 is a component of the 50S ribosome that is abundant in all bacteria and is specific for each bacterial species. We investigated whether RP-L7/L12 could be used to accurately diagnose pneumococcal pneumonia infection in mouse models of pneumonia and colonization generated by infecting CBA/JN or CBA/N mice, respectively, with S. pneumoniae strain 741. RP-L7/L12 detection by enzyme-linked immunosorbent assay accurately assessed active lung infection, as RP-L7/L12 levels decreased simultaneously with the bacterial lung burden after imipenem administration in the pneumonia mouse model. Based on the data, antibodies detecting RP-L7/L12 were applied to rapid immunochromatographic strips (ICS) for urine sample testing. When we compared the ICS test with the CAD kit in the pneumonia model, the results correlated well. Interestingly, however, when the lung bacterial burden became undetectable after antibiotic treatment, the ICS test was correspondingly negative, even though the same samples tested by the CAD kit remained positive. Similarly, while the ICS test exhibited negative results in the nasal colonization model, the CAD kit demonstrated positive results. Bacterial RP-L7/L12 may be a promising target for the development of new methods to diagnose infectious disease. Further studies are warranted to determine whether such a test could be useful in children.