Characterization of a human isolate of Tritrichomonas foetus (cattle/swine genotype) infected by a zoonotic opportunistic infection.

Tritrichomonas species flagellates (IMC strain) were isolated from the biliary tract of an individual who had developed cholecystitis as a complication of acquired agammaglobulinemia. Sequence analysis of Tritrichomonas sp. (IMC clone 2 (cl2)) was performed for several genetic regions including the ITS1-5.8S rDNA-ITS2 region, the cysteine protease (CP)-1, CP-2 and CP-4 to CP-9 genes, and the cytosolic malate dehydrogenase 1 gene. In addition to comparison of the variable-length DNA repeats in the isolate clone with those in T. foetus (Inui cl2) and the T. mobilensis (U.S.A.: M776 cl2) reference strains, this analysis showed that the Tritrichomonas sp. (IMC cl2) was T. foetus (cattle/swine genotype). Injection of T. foetus (IMC cl2) directly into the livers of CBA mice resulted in liver abscess formation on Day 7. Moreover, inoculation via orogastric intubation caused infection in the cecum on Day 5 in CBA mice co-infected with Entamoeba histolytica (HM-1: IMSS cl6). T. foetus (IMC cl2) was able to grow in YI-S medium for over 20 days, even at 5°C. These results indicate that the T. foetus isolate is able to survive in the feces and edible organ meat of the definitive host for a prolonged period of time, and it is possible that the parasite could infect humans.

Native valve endocarditis caused by Neisseria elongata Subsp. nitroreducens.

Neisseria elongata, a normal resident in the human oral cavity, rarely causes invasive infections. We herein report a case of endocarditis caused by Neisseria elongata subsp. nitroreducens that occurred in a patient without any apparent cardiac complications. The patient received aortic valve replacement following the administration of intravenous beta-lactam for five weeks. To our knowledge, this is the first published case in Japan of N. elongata infection in a patient without a prosthetic device.

[Comparison of antimicrobial use density (AUD) of carbapenem antibacterial agents and investigation of the drug susceptibility of Pseudomonas aeruginosa in 3 hospitals in southern Ibaraki Prefecture, Japan].

The optimal use of anti-Pseudomonas agents is an important issue in the prevention of a tolerance against Pseudomonas aeruginosa. We evaluated the effect of antimicrobial use density (AUD) of carbapenem on drug susceptibility. The AUD of the four carbapenems, imipenem (IPM/CS), panipenem (PAPM/BP), meropenem (MEPM), and biapenem (BIPM), was examined at three hospitals in Ibaraki Prefecture, between April and September 2004. The AUD was calculated using the Defined Daily Doses (DDD) methodology developed by the WHO. A drug susceptibility test was conducted on the 306 Pseudomonas aeruginosa strains randomly collected from clinical specimens at the three hospitals between September and December 2004. In accordance with the standards set by the Clinical and Laboratory Standards Institute (CLSI), minimal inhibitory concentration (MIC) was measured using the broth microdilution method. The results showed that the AUD of carbapenem at the three hospitals tended to be higher than that in other research results in Japan. At one of the three hospitals, the AUD of the PAPM was remarkably high compared to the other carbapenems. Furthermore, P. aeruginosa strains collected at this hospital showed a low susceptibility to carbapenem, and many highly tolerant strains were also observed in this hospital. In order to maintain the susceptibility of Pseudomonas aeruginosa to carbapenem, the overall extent of carbapenem use must be optimal. The use of antimicrobial drugs should be controlled properly at each hospital, in order to prevent excessive use of PAPM/BP from being used over a long period of time.

[Precautions regarding prevent acute urethritis caused by Neisseria meningitidis in Japan].

In Japan, Neisseria meningitidis is not sufficiently recognized as the primary causative bacteria of sexually transmitted diseases (STDs) as the number of reported cases is small. Here, we summarize reports from 3 medical institutions, present clinical courses for each case, as well recommending precautions to prevent infection with this bacterium. Fourteen cases of N. meningitidis urethritis (MU) were admitted between April 2001 and June 2006. All patients were male, consulted a doctor after experiencing subjective symptoms, such as micturition pain and pus discharge, and were diagnosed as having urethritis using isolation culture methods. In 8 of the 14 cases, history of sexual contact in the preclinical stage was confirmed, and contact was with a commercial sex worker (CSW) in 6 of these cases. Many of these patients recalled oral contact. All strains indicated susceptibility to many drugs, and there were no problems with treatment. With regard to serotype, there were 10 cases of type Y, 1 case of type B, and 3 cases that were not classifiable or unidentified. In addition, among the 9 strains that were subjected to genotype identification, 7 strains were ST-23. The recent increase in availability of nucleic acid amplification methods has facilitated simultaneous detection of Neisseria gonorrhoeae and Chlamydia trachomatis. However, we fear that MU will become latent. For screening of urethritis, Gram staining and culture of urethral material must be performed to detect this disease. The relationship of the detected strain and its role in the pathogenesis of meningitis are uncertain, but its serotype and genotype are common in cases of meningitis. Thus, precautions are required to prevent spread of this bacterium.