To identify risk factors and clinical outcomes in patients with bacteremia due to extended-spectrum beta-lactamase (ESBL) or carbapenemase-producing Escherichia coli, as well as to determine the prevalence and genetic background of such isolates. Case control study was performed with patients with E. coli bacteremia between January 2008 and May 2013 (n = 115) at a tertiary university hospital in Japan. Cases had ESBL-producing E. coli (ESBL-EC) whereas controls had non-ESBL-producing E. coli (non-ESBL-EC) isolates. A retrospective chart review was performed to identify risk factors and clinical outcomes. Isolates were characterized by antimicrobial susceptibility testing, polymerase chain reaction analysis for beta-lactamase genes, and multi-locus sequence typing. Of 115 unique cases of E. coli bacteremia, 30 (26.1%) were due to ESBL-EC and three (2.6%) were due to carbapenemase-producing E. coli. All three carbapenemase-producing E. coli isolates were IMP-6 and concurrently produced ESBL (ESBL/IMP-6-EC). ESBL-EC isolates showed multidrug resistance. Of the ESBL-EC isolates, CTX-M-27 was the most prevalent (33.3%), followed by CTX-M-14 (30%). Multi-locus sequence typing revealed that 19 (63.3%) isolates were ST131. The multivariate analysis identified nursing home-associated infections and antibiotic administration in the preceding 30 days as risk factors for ESBL-EC bacteremia. The 14-day mortality non-ESBL-EC, ESBL-EC, and ESBL/IMP-6-EC was 4.7% (4/85), 20% (6/30), and 66.7% (2/3), respectively. CTX-M-27, CTX-M-14, and ST131 were the most prevalent ESBL-EC isolates from bacteremic patients in a Japanese hospital. Further studies with larger sample sizes are warranted to investigate the clinical significance of ESBL-EC and ESBL/IMP-6-EC.

Countries in the Southeast Asia region have a high prevalence of soil-transmitted helminth, such as roundworm, whipworm, and hookworms [Ancylostoma duodenale, Necator americanus, Ancylostoma ceylanicum]. Recent molecular-based surveys have revealed that A. ceylanicum, a zoonotic hookworm, is likely the second most prevalent hookworm species infecting humans in that part of the world, while others have noted that this infection is an emerging public health risk not only for indigenous people but also for visitors from other countries. We recently encountered four cases of A. ceylanicum infection in Japanese individuals who returned from Southeast Asia and Papua New Guinea. Case 1 was a 25-year-old male who stayed in a rainforest in Malaysia for 4 weeks, where he developed abdominal pain and diarrhea in the third week. Eleven adult worms (five males, six females) were expelled after treatment with pyrantel pamoate and identified as A. ceylanicum based on morphological characteristics and DNA sequences of the mitochondrial cytochrome c oxidase subunit 1 (cox1) gene. Case 2 was a 26-year-old male who spent 2 years as an overseas cooperation volunteer for agriculture in Papua New Guinea. He did not note any symptoms at that time, though eggs were detected in feces samples at a medical check-up examination after returning. Although collection of adult worms was unsuccessful, DNA analysis of the eggs for cox1 and the ribosomal internal transcribed spacer (ITS)-1 and ITS-2 genes demonstrated that they were A. ceylanicum. Case 3 was a 47-year-old male who spent 1 month in a rural village in Lao People’s Democratic Republic and began suffering from watery diarrhea from the third week. A total of nine adult worms (three males, six females) were collected by endoscopic procedures and following treatment with pyrantel pamoate. Morphological examination and molecular analyses of the cox1 gene showed that they were A. ceylanicum. Case 4 was a 27-year-old male who participated in group travel to India for 5 days. Three weeks after returning, he developed abdominal pain and diarrhea. Hookworm eggs were found in feces samples and developed into larvae in culture, which were identified as A. ceylanicum based on molecular analysis of the cox1 gene. Eosinophilia was observed in all of the cases prior to treatment. A. ceylanicum should be recognized as an important etiologic pathogen of hookworm diseases in travelers to countries in the Southeast Asia and West Pacific Ocean regions.

We report a case of rat-bite fever in a 94-year-old woman with Streptobacillus notomytis infection. We established an epidemiologic link between exposure to rats and human infection by performing nested PCRs that detected S. notomytis in the intraoral swab specimens obtained from rats captured in the patient’s house.

Large-scale surveillance studies using molecular techniques such as pulsed-field gel electrophoresis (PFGE) have revealed that the spread of antibiotic-resistant pneumococci is due to clonal spread. However, in Japan, surveillance studies using such molecular techniques have never been done. Therefore, we conducted a pilot surveillance study to elucidate the present situation in Japan. Among the 145 isolates examined, the most prevalent serotype was type 19F (20%), for which most isolates were not susceptible to penicillin (86.2%) but were positive for the mef (A)/ mef (E) gene (89.7%). The secondmost prevalent was serotype 3 (16.6%), for which most isolates were susceptible to penicillin (87.5%) and positive for the erm (B) gene (91.7%). PFGE analysis showed that both serotypes consisted mainly of clonally identical or related isolates and, in particular, 38% of the type 19F isolates were indistinguishable from or closely related to the Taiwan 19F-14 clone. In addition, some of the Japanese type 23F isolates with the erm (B) gene were indistinguishable from or related to the Taiwan 23F-15 clone as analyzed by PFGE. Based on the results of our pilot study performed in a single institution, it is likely that international antibiotic-resistant clones have already spread in Japan; therefore, a nationwide surveillance study should be urgently conducted.