- Volume 52, Issue 2, 2003

A young female with no identifiable risk factors developed rapid, overwhelming Staphylococcus aureus endocarditis. Despite rapid sterilization of the blood and the mitral valve with optimal antimicrobials, she had persistent septic shock. In order to investigate this, the toxin-producing capacity of the infecting strain and the patient's ability to produce antibodies were determined. The strain produced high levels of both α-toxin and staphylococcal enterotoxin A (SEA), whilst the patient responded with modestly high levels of antibodies to α-toxin and low–normal levels to SEA. The patient was most probably susceptible to the actions of SEA and developed a toxic-shock-syndrome-like disease that further aggravated her valvular dysfunction. This case illustrates that optimal antimicrobial therapy alone is not sufficient treatment in patients with persistent toxic shock and that there is a need to evaluate immunomodulatory strategies in such patients.

There is increasing recognition of the emerging role of manganese regulation and acquisition in some pathogenic bacteria. Expression of the Enterococcus faecalis endocarditis-associated virulence factor EfaA is induced by growth in serum. It is demonstrated here that expression of the efaCBA operon encoding a putative ABC-type transporter is regulated by Mn2+. Transcription of efaCBA and EfaA production were repressed in Mn2+-supplemented medium. A Mn2+-responsive transcriptional regulator, EfaR, sharing 27 % identity with the Corynebacterium diphtheriae diphtheria toxin repressor (DtxR), was identified. In the presence of Mn2+, EfaR protein bound in vitro to the efaC promoter region. Analysis of the E. faecalis V583 genome revealed ten additional putative EfaR-binding sites, suggesting that manganese availability could have a broader regulatory role in infection. The results identify a new Mn2+-sensing regulator in enterococci that regulates the expression of a virulence factor implicated in enterococcal endocarditis.

Traditionally, the identification, epidemiology and spectrum of clinical diseases caused by Granulicatella adiacens and Abiotrophia defectiva are dependent upon their phenotypic characterization. During a 6-year period (July 1995–June 2001), seven and two α-haemolytic streptococci were identified as G. adiacens and A. defectiva, respectively, by 16S rRNA gene sequencing. Three patients with haematological malignancies and neutropenic fever had primary bacteraemia. Three patients with valvular problems or congenital heart disease had infective endocarditis. A patient with ischemic heart disease and cerebrovascular accident had infected aortic atheroma with dissection. A patient with recurrent pyogenic cholangitis had acute cholangitis and a patient with polypoid cystitis and benign prostatic hypertrophy had acute prostatitis. Four of the nine patients died, including all three with G. adiacens infective endocarditis or infected atheroma. For the seven G. adiacens isolates, the API 20 STREP system successfully identified one and five isolates as G. adiacens with >95 % and 80–90 % confidence, respectively, whereas the Vitek System (GPI) and ATB Expression system (ID32 STREP) successfully identified none and one isolate as G. adiacens. Of the two A. defectiva isolates, none of the three systems successfully identified either of them as A. defectiva. 16S rRNA gene sequencing is the technique of choice for identifying G. adiacens and A. defectiva, and early surgical intervention should be considered when G. adiacens endocarditis is diagnosed.

The characterization of integrons and their promoters in 156 antibiotic-resistant clinical isolates of the important zoonotic pathogens Salmonella enterica subsp. enterica serovars Typhimurium (S. Typhimurium) and Enteritidis (S. Enteritidis) from Norwegian hospitals were performed. Integrons were found in 64 of 66 S. Typhimurium isolates (97 %) and in 20 of 90 S. Enteritidis isolates (22.2 %) with the following sizes; 650, 1000, 1200, 1500, 1600, 1700, 2000 and 2100 bp. The integrons were further sequenced and the aadA1, aadA2, aadA5, aadB, pse-1, catB3, oxa1, dfrA1, dfrA12 and dfrA17 genes, as well as a fragment of the sat1 gene, were found embedded in cassettes. An internal fragment of the purG gene was additionally found as an artefact PCR amplicon.

To determine whether fluorescent amplified-fragment length polymorphism (FAFLP) analysis is an unbiased genome sampling technique, data were analysed from three different primer combinations, amplifying three independent fragment subsets from 123 isolates of Neisseria meningitidis. Using these data, dendrograms were generated with near-identical topologies that identified the same invasive clones of ET37 and ET5 and also identified the same outbreak clusters.

This study investigated the species prevalence and antibacterial resistance among enterococci isolated in Kuwait hospitals. They consisted of 415 isolates of Enterococcus faecalis (85.3 %), Enterococcus faecium (7.7 %), Enterococcus casseliflavus (4.0 %), Enterococcus avium (1.2 %), Enterococcus durans (1.0 %), Enterococcus gallinarium (0.5 %) and Enterococcus bovis (0.2 %) isolated from urine (36.6 %), blood (10.4 %), wound swabs (11.0 %), stool samples (12.0 %), high vaginal swabs (9.0 %), endocervical swabs (3.0 %) and miscellaneous sources (18.0 %). All of them were susceptible to linezolid. Fifty-two (12.5 %) isolates were ampicillin resistant but none of them produced β-lactamase. They were resistant to erythromycin (63.3 %), tetracycline (60.5 %), ciprofloxacin (40.0 %), chloramphenicol (28.0 %), vancomycin (2.6 %), and teicoplanin (2.6 %). Fourteen, 19 and 20 % of them expressed high-level resistance to gentamicin, kanamycin and streptomycin, respectively. All of the vancomycin-resistant strains carried the vanA phenotype and genotype. There was no evidence of clonal spread of the vancomycin-resistant isolates.

In this study the minimal inhibitory concentration (MIC) and minimal fungicidal concentration (MFC) of 5-hydroxytryptamine (5 HT, serotonin) against clinical isolates of Candida albicans (n = 11), Candida glabrata (n = 9), Candida tropicalis (n = 10) and Candida parapsilosis (ATCC 22019) using a broth microdilution test were investigated. In addition, it was examined whether delayed regrowth as a post-antifungal effect results following short exposure to 5 HT. 5 HT showed antifungal activity towards all isolates of Candida spp. The isolates yielded comparable MIC and MFC values of 5 HT in the range 0.91–7.34 mM and 1.83–14.68 mM, respectively. A lag in regrowth was dependent on the concentration tested. Treatment for 3 h at concentrations of 5 HT below and equipotent to the MFC resulted in a delayed regrowth of 8–12 h for isolates of Candida spp. In conclusion, these in vitro studies clearly demonstrate antifungal effects of 5 HT. Identifying the mode of action could be of great help in developing and researching new antifungal drugs.

Five cases of diphtheria were reported in Italy between January 1990 and June 2001. Three cases were confirmed microbiologically by the isolation of toxigenic Corynebacterium diphtheriae (two cases) and Corynebacterium ulcerans (one case). Over the same period, 11 cases of non-toxigenic C. diphtheriae infection were reported to the Italian Public Health Institute, from which the causative organism was isolated from a skin infection in one case and from the throat in the other ten. Seven of the throat isolates were associated with fever, severe pharyngitis and tonsillitis and were all biotype gravis. Because there are no standardized breakpoints, the antimicrobial sensitivities of C. diphtheriae were determined in accordance with the National Committee for Clinical Laboratory Standards guidelines for Streptococcus spp. other than Streptococcus pneumoniae. MICs for penicillin ranged between 0.125 and 0.250 mg l −1 and 7 out of 11 strains had a minimal bactericidal concentration (MBC)/MIC ratio ≥ 32. All strains were sensitive to clindamycin (MIC ≤ 0.25 mg l −1), rifampicin (MIC ≤ 1 mg l −1) and tetracycline (MIC ≤ 2 mg l −1), and showed moderate susceptibility to cefotaxime (MIC 0.75–1.5 mg l −1). Molecular typing (ribotyping) demonstrated the presence of several distinct ribotypes. The ribotype designated ‘D11’ has been documented amongst strains isolated in the UK, Russia, Germany, Romania and Sweden. Ribotype ‘D75’ has only been documented in the UK. The C. ulcerans strain had a ribotype pattern identical to that found in recent isolates from the UK.