François Caron

Serum bactericidal assay (SBA) is a functional assay that evaluates infection- and vaccine-induced neutralizing antibodies representing the serological correlate of protection against Neisseria meningitidis. However, it is time consuming due to its readout using the enumeration of colony-forming units (CFUs), making this conventional SBA (C-SBA) difficult for large-scale use. We developed a new SBA method that takes advantage of a bioluminescence N. meningitidis serogroup B (BioLux-SBA). The assay development steps involved the human complement source validation, the setup of the optimal incubation time, and the assessment of intra-day and inter-day variability. BioLux-SBA was then compared to C-SBA using a serum collection of Norman children vaccinated in 2011 with MenBvac, an OMV meningococcal vaccine. While a conventional approach requests 48 h of work to test 24 sera per day, BioLux-SBA takes only 5 h to test 96 sera per day. The SBA titers (n = 10) correlated with R² of 0.98 (p-value < 0.0001). The deposition of terminal complement components (C5b-C9) measured by flow cytometry on the bacterial surface well correlated with BioLux SBA titers. This high-throughput method to evaluate the immunogenicity of meningococcal vaccines appears to be a reliable method for an OMV meningococcal B vaccine and requires further assessment in other laboratories and against other meningococcal vaccines.

Defined by an infection of the ventricular system of the brain, ventriculitis is usually known as a health-care associated infection. In contrast, primary pyogenic ventriculitis complicating community-acquired meningitis is uncommon, and mainly described in infants. Only seven cases that have occured in adults have been found in the international literature. We report here a new case due to Neisseria meningitidis occurring in an 85 year-old-man. The comparison with previous reports allows to drawn several conclusions: (i) cases occurred in relatively old adults (median age: 65 years); (ii) Streptococcus pneumoniae, N. meningitiditis and Staphylococcus aureus are the leading responsible pathogens; (iii) atypical clinical presentation seems the rule in which meningism often lacks; (iv) in absence of clinical or biological specific parameters, modern brain imaging such as magnetic resonance imaging with gadolinium enhancement is of utmost importance for the diagnosis, leading to anticipate an increase of the diagnosis in the near future, thanks to easier access to such exploration; (v) death or serious sequelae commonly occurred; (vi) prolonged antibiotic courses (6 weeks to 3 months) have been used, without strong rational. In the given case, the patient presented with a lack of meningeal irritation signs. The diagnosis was made by MRI considering a lasting confused state. A four-week antibiotic regimen was successful, combining two weeks of intravenous cefotaxime followed by two weeks of oral levofloxacin much easier to administrate and allowing early rehabilitation. Primary bacterial ventriculitis is a real diagnosis challenge. Larger indications of MRI for bacterial meningitis, particularly in cases with an atypical presentation or poor evolution would certainly increase the number of diagnosis.

Outcome of patients with streptococcal prosthetic joint infections (PJIs) is not well known. We performed a retrospective multicenter cohort study that involved patients with total hip/knee prosthetic joint (THP/TKP) infections due to Streptococcus spp. from 2001 through 2009. Ninety-five streptococcal PJI episodes (50 THP and 45 TKP) in 87 patients of mean age 69.1 ± 13.7 years met the inclusion criteria. In all, 55 out of 95 cases (57.9 %) were treated with debridement and retention of the infected implants with antibiotic therapy (DAIR). Rifampicin-combinations, including with levofloxacin, were used in 52 (54.7 %) and 28 (29.5 %) cases, respectively. After a mean follow-up period of 895 days (IQR: 395–1649), the remission rate was 70.5 % (67/95). Patients with PJIs due to S. agalactiae failed in the same proportion as in the other patients (10/37 (27.1 %) versus 19/58 (32.7 %); p = .55). In the univariate analysis, antibiotic monotherapy, DAIR, antibiotic treatments other than rifampicin-combinations, and TKP were all associated with a worse outcome. The only independent variable significantly associated with the patients’ outcomes was the location of the prosthesis (i.e., hip versus knee) (OR = 0.19; 95 % CI 0.04–0.93; p value 0.04). The prognosis of streptococcal PJIs may not be as good as previously reported, especially for patients with an infected total knee arthroplasty. Rifampicin combinations, especially with levofloxacin, appear to be suitable antibiotic regimens for these patients.

Acute uncomplicated cystitis (AUC) is an ideal target of optimization for antibiotic therapy in primary care. Because surveillance networks on urinary tract infections (UTI) mix complicated and uncomplicated UTI, reliable epidemiological data on AUC lack. Whether the antibiotic choice should be guided by a rapid urine test (RUT) for leukocytes and nitrites has not been extensively studied in daily practice. The aim of this primary care study was to investigate local epidemiology and RUT-daily use to determine the optimal strategy.

There is currently a lack of consensus for the diagnosis, investigations and treatments of acute bacterial prostatitis (AP).

The laboratory diagnosis and antibiotic treatment of urinary tract infections (UTIs) are very different depending on the clinical context. It is critical to distinguish between uncomplicated infections and infections complicated by abnormalities of the urinary tract or other host factors. Microscopic examination combined with urine culture remains the test of reference, excepted for uncomplicated cystitis. It requires rigorous method and analysis taking into account of clinical data. For empirical therapy, the choice is well codified in case of community acquired UTIs since the bacterial species involved are very stable over time and space, and since their antibiotic resistances are well known (with currently a high prevalence of resistance not only to aminopenicillins but also to amoxicillin-clavulanate and trimethoprim-sulfamethoxazole); in contrast, the treatment of nosocomial UTIs is difficult because of the diversity of causative organisms and of antibiotic resistance profiles.

Acute infective endocarditis are due to highly virulent microorganisms, such as Staphylococcus aureus, able to invade normal endocardium, causing fulminant local damages (valvular destruction) as well as general damages (sepsis, metastasis), so that clinical manifestations are usually dramatic. Empirical antimicrobial therapy must be given immediately, using combinations active against the most commonly encountered pathogens. Other treatments are frequently necessary: medical therapy for heart failure, surgery of valvular reconstruction or replacement, respiratory assistance and other supportive measures. Such management requires cooperation of several disciplines.