Short-course antibiotic treatment of bone and joint infections in children: a retrospective study at Montpellier University Hospital from 2009 to 2013.

BACKGROUND: Acute haematogenous bone and joint infections (AHBJI) represent a diagnostic and therapeutic emergency in children, with significant potential sequelae in the case of delayed treatment. Although historically the recommendations for treatment have been based on surgery and prolonged antibiotic therapy, recent studies have demonstrated that short-course antibiotic therapy is also effective. OBJECTIVES: We evaluated a short-term antibiotic protocol for both osteomyelitis and septic arthritis in a 6 year retrospective study at the University Hospital of Montpellier. METHODS: This protocol was based on an initial intravenous treatment with a re-evaluation after 48 h and an early switch to oral therapy in the case of a favourable clinical course for a minimum total duration of 15 days. Antibiotics were selected based on local microbiological epidemiology and systematically adapted to bacteriological results. RESULTS: One hundred and seventy-six cases of AHBJI were included, comprising 56 patients with osteomyelitis, 95 with septic arthritis and 25 who had both of these. The aetiological agent was identified in 42% of the cases, with the main pathogens being Staphylococcus aureus (39%) and Kingella kingae (27%). The mean intravenous treatment duration was 4 days, while the total treatment duration was 15 days. There were no treatment failures, mild sequelae occurred in 1% of the cases and the secondary surgical revision rate was 7%. CONCLUSIONS: The results of this study are comparable to those reported for evaluations of prolonged antibiotic therapy protocols, thus indicating that a common short-term antimicrobial therapy for the management of both osteomyelitis and septic arthritis (minimum of 15 days) is a viable option for treating AHBJI in children. Further prospective studies to confirm these findings are hence warranted.

Skin microbiota is the main reservoir of Roseomonas mucosa, an emerging opportunistic pathogen so far assumed to be environmental.

Roseomonas spp. are increasingly involved in human infectious diseases. The environmental source for infection is generally admitted in published cases owing to the origin of most Roseomonas species and to their affiliation to the family Acetobacteraceae in Rhodospirillales, which mainly groups environmental bacteria. For a better delineation of Roseomonas habitat and infectious reservoir, we related phenotype, phylotype (16S rRNA gene), genomotype (pulsed-field gel electrophoresis) and origin of 33 strains isolated from humans, hospital environment and natural environment. Genetic and metagenomic databases were also surveyed. The population structure of the genus showed clades associated with humans, whereas others grouped environmental strains only. Roseomonas mucosa is the main human-associated species and the study supported the idea that opportunistic infections due to this species are related to the patient skin microbiota rather than to the environment. In contrast, some strains belonging to other species isolated from patients with cystic fibrosis were related to environmental clades, suggesting an exogenous source for patient colonization. Accurate knowledge about the reservoirs of opportunistic pathogens that have long been considered of environmental origin is still needed and would be helpful to improve infection control and epidemiological survey of emerging human pathogens.

[Tigecycline: CMI 50/90 towards 1766 Gram-negative bacilli (3rd generation cephalosporins resistant enterobacteriaceae), Acinetobacter baumannii and Bacteroides fragilis group, University Hospital - Montpellier, 2008-2011]. / Tigécycline : CMI 50/90 vis-à-vis de 1766 bacilles à Gram-négatif (entérobactéries résistantes aux céphalosporines de troisième génération), Acinetobacter baumannii et Bacteroides du groupe fragilis, CHU - Montpellier, 2008-2011.

Tigecycline is a new glycylcyclin with a wide spectre including multi-resistant bacteria. Our laboratory tests in routine the in vitro activity of the TGC towards clinically significant isolates of 3rd generation cephalosporins resistant enterobacteriaceae (EC3R), Acinetobacter baumannii and Bacteroides fragilis group (BFG). The objective of this study is to describe the in vitro activity of TGC against these strains isolated between 2008 and 2011 in the university hospital of Montpellier. In this study period, 1070 isolates EC3R including 541 extended spectrum ß-lactamase-producers (ESBL) strains, 47 isolates of A. baumannii including 40 multi-resistant isolates and 645 isolates of BFG were tested. Minimum inhibitory concentrations (MIC) were determined using the E-test method. TGC was active against 86.2% of EC3R with a MIC 90 less or equal to 1mg/L (Escherichia coli being the most sensitive species). A. baumannii and BFG were also inhibited at low concentrations of TGC with a MIC 90 less or equal to 2mg/L respectively for 47% and 84.2% of the isolates. Our study confirms the activity of TGC against the EC3R including ESBL-producers strains. The relevance of the therapeutic use of TGC on the BFG isolates with a MIC greater than 2mg/L should be better documented. Often prescribed in therapeutic impasse, the proper use of TGC would require: clarifying the threshold of sensitivity for some species (i.e., A. baumannii, Bacteroides fragilis group); a better understanding of correlation between in vitro and in vivo activity.

Clinical and antimicrobial susceptibility data of 140 Streptococcus pseudopneumoniae isolates in France.

We report retrospective analysis of the clinical and antimicrobial susceptibility data of 140 Streptococcus pseudopneumoniae isolates. Strains were isolated mostly from respiratory tract samples from patients with underlying diseases. In the case of infection, pneumonia, mainly aspiration pneumonia, was the most frequent (27.1% of the patients). We documented high rates of decreased susceptibilities and resistance to erythromycin and tetracycline (57% and 43% of the isolates, respectively), as well as reduced susceptibility to penicillin in 21% of the isolates.

Intragenomic and intraspecific heterogeneity of the 16S rRNA gene in seven bacterial species from the respiratory tract of cystic fibrosis patients assessed by PCR-Temporal Temperature Gel Electrophoresis.

16S rRNA gene-based cultivation-independent methods are increasingly used to study the diversity of microbiota during health and disease. One bias of these methods is the variability of 16S rRNA gene that may exist among strains of a same species (intraspecific heterogeneity) or between rrs copies in a genome (intragenomic heterogeneity). We evaluated the level of intraspecific and intragenomic 16S rDNA variability in seven species frequently encountered in respiratory tract samples in cystic fibrosis (CF). A total of 179 strains were subjected to V3 region 16S rDNA PCR-TTGE. Using this easy-to-perform and rapid method, different levels of V3 region rrs heterogeneity were demonstrated. No intraspecific and intragenomic rrs heterogeneity was demonstrated for Moraxella catarrhalis (n=16), Pseudomonas aeruginosa (n=31) and Streptococcus pneumoniae (n=14) showing a single PCR-TTGE band characteristic of the species. Low level of intraspecific heterogeneity was observed for Staphylococcus aureus (n=30), Stenotrophomonas maltophilia (n=29) and Achromobacter xylosoxidans (n=28), and 17%, 38% and 96% of these strains showed intragenomic heterogeneity (two to four different rrs copies), respectively. Haemophilus influenzae (n=31) displayed the higher level of intraspecific variability with 23 different PCR-TTGE patterns and 61% of the strains showed intragenomic rrs heterogeneity (two to four different rrs copies). Although only one hypervariable region of the 16S rRNA gene was explored, intraspecific and intragenomic rrs heterogeneity was frequently observed in this study and should be taken into consideration for a better interpretation of 16S rRNA gene-based diversity profiles in denaturing gels and to avoid any overestimation of the respiratory microbiota diversity in CF.

Adaptation and evaluation of the Randox full-range CRP assay on the Olympus AU2700.

The implementation of a high-sensitivity CRP (hs-CRP) assay as a routine laboratory parameter may be necessary. A single CRP method that could yield reliable results for the whole concentration range (0.1-200 mg/L) would be the most practical solution for the laboratory setting. The aim of this study was to assess the Randox full-range CRP assay on the Olympus AU2700 biochemistry analyzer and evaluate its analytical performance on serum and heparin plasma samples. The Randox CRP turbidimetric assay was compared with the existing CRP assay used routinely on the Olympus AU2700. The analytical performance of the Randox CRP with both Olympus CRP reagents (CRP for normal application and hs-CRP) was good. We found that the Randox CRP method in the range of 0.5-160 mg/L was closely correlated to the Olympus CRP and hs-CRP for serum samples. According to a Bland-Altman analysis, the serum and heparinized samples showed an excellent agreement in CRP concentrations throughout the entire range (mean difference = -0.035 +/- 1.806 mg/L) as well as in CRP levels <10 mg/L. Our data indicate that Randox full-range CRP measurements using an immunoturbidimetry assay on Olympus systems perform as well for routine diagnostics as other high-sensitivity applications using serum or heparin plasma.

Experimental simulation of the effects of increased geomagnetic activity upon nocturnal seizures in epileptic rats.

This experiment was designed to simulate experimentally the specific parameters of geomagnetic activity that evoke epileptic seizures. The numbers of overt limbic seizures (rearing, paroxysmal forelimb clonus and falling) in a population of epileptic rats were recorded nightly for 65 successive days between 0200 and 0400 h during red light conditions. On some nights an experimental 7 Hz magnetic field whose magnitudes shifted in successive steps from zero to approximately 50 nT every 3 min was presented. The partial regression coefficients from the analysis indicated that either the presence of the 'synthetic' geomagnetic activity or increased magnitudes of the daily, natural geomagnetic activity (regional range approximately 10-70 nT) during the observational period significantly (P < 0.05) increased the proportion of nightly seizures. The effect sizes (6-8%) for both magnetic sources were comparable and additive. Concerted efforts to experimentally simulate the temporal profiles of geomagnetic activity may help reveal the neuromechanisms by which biobehavioral changes during geomagnetic perturbations occur within susceptible populations.