Liver abscess of Actinomyces israelii in a hemodialysis patient: case report and review of the literature.

We had encountered a 74-year-old woman on hemodialysis therapy suffering from liver abscess of Actinomyces israelii. Percutaneous drainage of the abscess before starting antimicrobial therapy followed by correct microbiological identification and susceptibility test led us to determine long treatment with ampicillin and to a successful outcome. Periodontitis was thought to be a possible entry of actinomyces. Hepatic actinomycosis should be recognized as one of the important infectious diseases among patients of end-stage renal disease.

Molecular emm genotyping and antibiotic susceptibility of Streptococcus dysgalactiae subsp. equisimilis isolated from invasive and non-invasive infections.

To analyse the characteristics of infections caused by Streptococcus dysgalactiae subsp. equisimilis, clinical isolates (n=145) were collected at 11 medical institutions between September 2003 and October 2005. These isolates belonged to Lancefield group A (n=5), group C (n=18) or group G (n=122). Among all isolates, 42 strains were isolated from sterile samples such as blood, synovial fluid and tissue specimens from patients who were mostly over 50 years with invasive infections, and included seven cases of streptococcal toxic shock syndrome and necrotizing fasciitis. In contrast, the remaining 103 were isolated mainly from patients of all age groups with non-invasive infections such as pharyngotonsillitis. These isolates were classified into 25 types based on emm genotyping. A significant difference in emm types was observed between isolates from invasive and non-invasive infections (P<0.001): stG485, stG6792 and stG2078 predominated among isolates from invasive infections. A phylogenetic tree of complete open reading frames of emm genes in this organism showed high homology with those of Streptococcus pyogenes, but not with those of other streptococci. The presence of five different clones was estimated based on DNA profiles of isolates from invasive infections obtained by PFGE. Genes for resistance to macrolides [erm(A), three isolates; erm(B), five isolates; mef(A), seven isolates] and levofloxacin (mutations in gyrA and parC, four isolates) were identified in this organism. These results suggest the need for further nationwide surveillance of invasive infections caused by S. dysgalactiae subsp. equisimilis.

Impact of reporting gram stain results from blood culture bottles on the selection of antimicrobial agents.

We assessed the usefulness of reporting direct blood Gram stain results compared with the results of positive blood cultures in 482 episodes and monitored impact on selection of antimicrobial treatment. We found that the reporting groups "Staphylococcus spp," "Pseudomonas spp and related organisms," and "yeasts" identified in this way matched perfectly with later culture identification. When the report indicated Staphylococcus spp or Pseudomonas spp and related organisms, physicians started or changed antimicrobials suitable for these bacteria more frequently than when "other streptococci" and "family Enterobacteriaceae" were reported (P < .05). Incorrect recognition of Acinetobacter spp as Enterobacteriaceae family is still the most challenging problem in this context. Gram stain results that definitively identify Staphylococcus spp, Pseudomonas spp and related organisms, and yeasts reliably can be rapidly provided by clinical laboratories; this information has a significant impact on early selection of effective antimicrobials. Further investigation is needed to assess the clinical impact of reporting Gram stain results in bacteremia.

Multicenter study to evaluate bloodstream infection by Helicobacter cinaedi in Japan.

Helicobacter cinaedi has being recognized as an important human pathogen which causes bloodstream infections. Although the first case of bacteremia with this pathogen in Japan was reported in 2003, the true prevalence of H. cinaedi as a pathogen of bloodstream infections in this country is not yet known. Therefore, the aim of our study was to assess the incidence of bacteremia with H. cinaedi in Japan. We conducted a prospective, multicenter analysis in 13 hospitals during 6 months in Tokyo, Japan. Among positive blood cultures from 1 October 2003 to 31 March 2004, isolates suspected of being Helicobacter species were studied for further microbial identification. Identification of the organisms was based on their biochemical traits and the results of molecular analysis of their 16S rRNA gene sequences. A total of 16,743 blood culture samples were obtained during the study period, and 2,718 samples (17.7%) yielded positive culture results for coagulase-negative staphylococci. Among nine isolates suspected to be Helicobacter species, six isolates were finally identified as H. cinaedi. The positivity rate for H. cinaedi in blood culture was 0.06% of total blood samples and 0.22% of blood samples with any positive culture results. All patients with bacteremia with H. cinaedi were found to have no human immunodeficiency virus (HIV) infection, but many of them had complications with either malignancy, renal failure, or a history of surgical operation. Therefore, our results suggest that bacteremia with H. cinaedi is rare but can occur in compromised hosts other than those with HIV infection in Japan.

[Interpretation of the results of blood culture and interventional role by clinical laboratory physicians].

Blood culture has long been recognized as the gold standard for the definitive diagnosis of bacterial and fungal infections. However, fewer blood cultures have been tested and their results have not been fully used in Japan. Clinical laboratory physicians should play an interventional role, such as recommending blood culture tests in patients with infectious disease or fever of unknown origin. In our hospital, clinical laboratory physicians act as on-call consultants. The yearly number of consultations is between 500 and 700, and consultations concerning infectious disease have increased up to 40% in the past 5 years. As a result, the number of blood cultures and the percentage of 2-set blood collections have increased in order to increase the positivity rate and determine whether the results obtained were contaminated. However, physicians sometimes misunderstand the results of blood culture, and they assume that the identified organism was causative, or that sepsis did not exist if the culture is negative. Clinical laboratory physicians should act as consultants more frequently, concerning the interpretation of blood culture results, and the choice of antimicrobial agents, because the inappropriate use of antimicrobial agents leads to higher mortality and higher medical costs. Finally, collaboration between clinical laboratory physicians and co-medical staff such as the infection control team, nurses and pharmacists is necessary.