Actinomyces species: A Danish Survey on Human Infections and Microbiological Characteristics

Department of Bacteriology, Mycology and Parasitology, Statens Serum Institute, Copenhagen, Departments of Clinical Microbiology.
The Open Microbiology Journal 02/2009; 3(1):113-20. DOI: 10.2174/1874285800903010113
Source: PubMed


This study compared phenotypic and genotypic identification of Actinomyces strains, tested susceptibility to antibiotics and evaluated their clinical importance. Thirty-four Actinomyces strains were examined; sixteen type strains, and 18 clinical strains from different hospitals in Denmark from the period 2003-2005. Partial 16S rDNA sequencing using a stretch of 526 bases was used for genotypic identification. Susceptibility testing was done by E-test. The antibiotics examined were: benzylpenicillin, piperacillin with tazobactam, ceftriaxone, meropenem, erythromycin, clindamycin, linezolid, moxifloxacin, tetracycline and tigecycline. Clinical parameters were obtained by reviewing patient records. There was poor agreement between the phenotypic and genotypic identification. Phenotypic tests were helpful in identifying strains closely related by DNA sequences. The strains were sensitive to the examined antibiotics except for moxifloxacin to which most strains were resistant, and a few strains were resistant to meropenem and tetracycline. The clinical strains were from many different types of infections and locations. None of the patients was described as having typical actinomycetic lesions, and an apparently good outcome was obtained with different treatment regimens.

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    • "Possible explanations for treatment failure are drug-resistant co-pathogens and poor penetration of the drug caused by avascularity and induration of the infected area [14]. Although reported antimicrobial susceptibility tests indicate that most Actinomyces are susceptible to penicillin and amoxicillin, Actinomyces may acquire antibiotic resistance during antibiotic treatment [15,16]. "
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    ABSTRACT: There have been few studies of pulmonary actinomycosis, which is an uncommon anaerobic infection. Consequently, the optimal therapeutic regimen, appropriate duration of treatment, long-term prognosis, and factors predicting prognosis are not well established. We retrospectively reviewed the medical records of histopathologically confirmed cases of pulmonary actinomycosis seen between November 2003 and December 2012. The study included 68 patients with a mean age of 58.4 +/- 11.6 years. Of the 68, initial surgery was performed in 15 patients (22.1%), while the remaining 53 (77.9%) received antibiotic therapy initially. In the initial antibiotic group, 45/53 (84.9%) were cured without relapse (median antibiotic duration 5.3 months). 5/53 (9.4%) patients were refractory medically (median antibiotic duration 9.7 months), and 3/53 (5.7%) experienced a recurrence (median time to relapse 35.3 months). In the initial surgery group, 14/15 (93.3%) were cured and treatment failure occurred in one (6.7%). In the multivariate analysis, the absence of an antibiotic response at 1 month was the only independent factor associated with a poor treatment outcome, with an adjusted odds ratio of 49.2 (95% CI, 3.34-724.30). There was no significant difference in treatment outcome based on the size of the parenchymal lesion, comorbidities, whether intravenous antibiotics were used, antibiotic therapy duration, or whether the initial treatment was surgical. Antibiotic treatment with or without surgery was effective for treatment of pulmonary actinomycosis. Nevertheless, treatment failure or recurrence occurred in a considerable proportion of patients, especially those resistant to the initial antibiotic treatment.
    BMC Infectious Diseases 01/2014; 14(1):10. DOI:10.1186/1471-2334-14-10 · 2.61 Impact Factor
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    • "One case of cystitis was reported in a revision of Actinomyces spp. infections in Denmark that was treated with a short-course of antimicrobials (cefuroxime and meropenem for 9 days) [6]. "
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    ABSTRACT: Bacteremia due to Actinomyces neuii has been reported in the literature 14 times. A. neuii is an endogenous organism that has been cultured in clinical specimens of the genitourinary tract; we are reporting a unique case of Actinomyces neuii postoperative testicular abscess with bacteremia which was successfully treated with surgery and a short course of parenteral antimicrobials.
    IDCases 01/2014; 1(3). DOI:10.1016/j.idcr.2014.05.002
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    • "Pulmonary actinomycosis is a rare bacterial infection that is sometimes difficult to diagnose. Currently, PCR following 16S rRNA gene sequencing is the preferred method of detecting Actinomyces in clinical material (Hansen et al., 2009). This disease generally results in non-specific respiratory symptoms and various radiological findings. "
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    ABSTRACT: We report what is believed to be the first case of pulmonary Actinomyces graevenitzii infection presenting as organizing pneumonia. Fever and night sweats developed in a 69-year-old male. The only abnormal laboratory data were an elevated erythrocyte sedimentation rate and C-reactive protein level. On chest images, multiple consolidations with air bronchograms were seen in the bilateral lungs. Histological examination from lung biopsy revealed a pattern of organizing pneumonia with microabscesses, but definitive diagnosis was not obtained because culture from lung specimen was negative. A. graevenitzii was eventually identified in the lung biopsy specimen by detection of an Actinomyces-specific PCR product followed by 16S rRNA gene sequencing. The patient was treated with high-dose ampicillin intravenously for 1 month, followed by oral amoxicillin and clarithromycin for 6 months, and recovered. We suggest that actinomycosis can present as organizing pneumonia, and identification of infection by PCR analysis and rRNA gene sequencing is a useful strategy in cases that are difficult to diagnose.
    Journal of Medical Microbiology 04/2012; 61(Pt 8):1156-8. DOI:10.1099/jmm.0.040394-0 · 2.25 Impact Factor
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