Evaluating the serological status of COVID-19 patients using an indirect immunofluorescent assay, France.

An indirect in-house immunofluorescent assay was developed in order to assess the serological status of COVID-19 patients in Marseille, France. Performance of IFA was compared to a commercial ELISA IgG kit. We tested 888 RT-qPCR-confirmed COVID-19 patients (1302 serum samples) and 350 controls including 200 sera collected before the pandemic, 64 sera known to be associated with nonspecific serological interference, 36 sera from non-coronavirus pneumonia and 50 sera from patient with other common coronavirus to elicit false-positive serology. Incorporating an inactivated clinical SARS-CoV-2 isolate as the antigen, the specificity of the assay was measured as 100% for IgA titre ≥ 1:200, 98.6% for IgM titre ≥ 1:200 and 96.3% for IgG titre ≥ 1:100 after testing a series of negative controls. IFA presented substantial agreement (86%) with ELISA EUROIMMUN SARS-CoV-2 IgG kit (Cohen's Kappa = 0.61). The presence of antibodies was then measured at 3% before a 5-day evolution up to 47% after more than 15 days of evolution. We observed that the rates of seropositivity as well as the titre of specific antibodies were both significantly higher in patients with a poor clinical outcome than in patients with a favourable evolution. These data, which have to be integrated into the ongoing understanding of the immunological phase of the infection, suggest that detection anti-SARS-CoV-2 antibodies is useful as a marker associated with COVID-19 severity. The IFA assay reported here is useful for monitoring SARS-CoV-2 exposure at the individual and population levels.

Bartonella henselae is usually not viable in lymph nodes of patients with cat scratch disease.

Bartonella henselae, the agent of cat scratch disease (CSD), appears to be a common organism responsible for lymphadenitis in both adults and children. There is a very low isolation rate for B. henselae from lymph nodes of patients with CSD. Our objective was to evaluate B. henselae viability in a large series of lymph nodes from patients with CSD. From January to November 2016, we analyzed lymph node biopsy samples from patients diagnosed with CSD. We used reverse transcription-quantitative polymerase chain reaction (RT-qPCR) to detect B. henselae RNA, as well as cultures, histological analyses, and fluorescence in situ hybridization (FISH). We tested 87 lymph nodes positive for B. henselae DNA but only 8 (9%) presented with B. henselae RNA. We did not find a significant difference for the pap threshold cycle (CT) values between RNA-positive and RNA-negative lymph nodes (p = 0.5). Cultures, histological analyses, and FISH were negative for all the tested samples. We provide evidence that B. henselae are not or are rarely viable in most cases in the lymph nodes of patients with CSD.

Francisella tularensis aortitis.

Francisella tularensis, the agent of tularemia, is a Gram-negative coccobacillus primarily pathogen for animals and occasionally for humans. The clinical manifestations of tularemia include pneumonia, ulceroglandular, oropharyngeal, or typhoidal disease. Rare manifestations are also described, but to our knowledge, we describe here the first case of F. tularensis aortitis in a human. Diagnosis was confirmed by the presence of F. tularensis in blood culture, by the presence of F. tularensis DNA in the aortic biopsy and by specific IgG and IgM responses against the bacteria. The outcome was favorable after surgery and specific antimicrobial therapy.

Complementarity between targeted real-time specific PCR and conventional broad-range 16S rDNA PCR in the syndrome-driven diagnosis of infectious diseases.

Molecular tools have shown an added value in the diagnosis of infectious diseases, in particular for those caused by fastidious intracellular microorganisms, or in patients receiving antibiotics before sampling. If 16S rDNA amplification had been gradually implemented in microbiology laboratories, specific real-time polymerase chain reaction (PCR) would have permitted an increase in the sensitivity of molecular methods and a reduction of contamination. Herein, we report our experience in the diagnosis of infectious diseases over two years, during which 32,948 clinical samples from 18,056 patients were received from France and abroad. Among these samples, 81,476 PCRs were performed, of which 1,192 were positive. Molecular techniques detected intracellular microorganisms in 31.3 % of respiratory samples, 27.8 % of endocarditis samples and 51.9 % of adenitis samples. Excluding intracellular bacteria, 25 % of the positive samples in this series were sterile in culture. Conventional broad-range PCR permitted the identification of fastidious and anaerobic microorganisms, but specific real-time PCR showed a significant superiority in the diagnosis of osteoarticular infections, in particular for those caused by Kingella kingae and Staphylococcus aureus, and for endocarditis diagnosis, specifically when Streptococcus gallolyticus and Staphylococcus aureus were involved. The sensitivity of conventional broad-range PCR was 62.9 % concerning overall diagnoses for which both techniques had been performed. These findings should lead microbiologists to focus on targeted specific real-time PCR regarding the clinical syndrome. Finally, syndrome-driven diagnosis, which consists of testing a panel of microorganisms commonly involved for each syndrome, permitted the establishment of 31 incidental diagnoses.

Planctomycetes DNA in febrile aplastic patients with leukemia, rash, diarrhea, and micronodular pneumonia.

We found Planctomycetes DNA in 2 out of 100 blood samples from patients suffering from leukemia with neutropenia induced by chemotherapy, as well as fever, rash, pneumonia, and diarrhea. Antibiotic-resisting Planctomycetes may be pathogenic in these patients.

[Paradoxical reactions and responses during antibiotic treatment for Mycobacterium ulcerans infection (Buruli ulcer). Four cases from French Guiana]. / Réponses et réactions paradoxales au cours du traitement médicamenteux de l'infection à Mycobacterium ulcerans (ulcère de Buruli). Quatre observations en Guyane française.

BACKGROUND: In recent years, first-line therapy for Mycobacterium ulcerans infection in French Guiana has consisted of antibiotics active against this organism. Two regimens are used comprising rifampicin associated with clarithromycin or amikacin. PATIENTS AND METHODS: We describe four patients presenting apparent worsening of their lesions during treatment: ulceration of a nodular lesion in a 32-year-old woman and worsening of an ulcerated lesion in three patients aged 16, 27 and 79 years. DISCUSSION: In these 4 patients, we concluded that the symptoms were caused by a paradoxical response or a reaction, a phenomenon already described in tuberculosis and leprosy. Such worsening is transient and must not be misinterpreted as failure to respond to treatment. The most plausible pathophysiological hypothesis involves the re-emergence of potentially necrotizing cellular immunity secondary to the loss of mycolactone, a necrotizing and immunosuppressive toxin produced by M. ulcerans, resulting from the action of the antibiotics.

Paleoserological detection of Coronavirus antigens in dental calculus of human remains dating from the beginning of the 19th century, French Ardennes.

OBJECTIVE: Vanishing viral RNA restricts our ability to detect ancient pathogens, so, we used paleo serological approaches to trace the dynamics of the Coronavirus in ancient populations. MATERIALS AND METHODS: We investigated 10 ancient dental calculus samples collected from a cemetery dated to the beginning of the 19th century and excavated in Charleville-Mézières. After paleoserum samples were extracted from dental calculus, paleoserology using mini-line-blot incorporating one alpha-Coronavirus (Coronavirus 229 E) and two beta-Coronavirus (Coronavirus OC 43, SARS-CoV-2) antigens and controls was completed by an automated Western blotting assay. RESULTS: Once appropriate controls had validated the data, mini-line-blot detected antibodies against the two beta-Coronavirus antigens in individuals US1300 and US1339, automated Western blotting confirming one beta-Coronavirus antigen for individual US1300 and an additional individual US1326. DISCUSSION: Combing mini-line blot and automated Western blot assays made it possible to detect immunoreactive immunoglobulin tracing circulation of Coronavirus in France at the very beginning of the 19th century.

Ultra-high performance size-exclusion chromatography of synthetic polymers: demonstration of capability.

Ultra-high performance size-exclusion chromatography (UHP SEC) is a newly developed disruptive technology that allows the high-resolution separation of synthetic polymers in as little as 2 min. The capability of UHP SEC for the characterization of synthetic polymers in organic solvents has been demonstrated. Using the Waters ACQUITY UPLC® H-Class system and ethylene-bridged hybrid size-exclusion chromatography (SEC) columns packed with 1.7 to 2.5-µm particles with pore sizes ranging from 45 to 900 Å, size-based separations of polystyrene and poly(methyl methacrylate) standards in tetrahydrofuran and poly(ethylene oxide) standards in 20 mM ammonium acetate in methanol are achieved within 2-4 min. The speed of analysis is about ten times faster than conventional SEC separations, and greater resolution is achieved. Average molecular weights of selected commercial polymers have been determined using ultra-high performance and conventional SEC. Average M data of analyzed samples are in good agreement using the two approaches. An inherent limitation of SEC in UHP mode is the characterization of very high M polymers (above ca. 2 million Da) due to the deformation and/or mechanical shearing of large molecules at high flow rates.

Bilateral choroidopathy in systemic lupus erythematosus.

We report a case of bilateral choroidopathy in a 35-year-old woman with systemic lupus erythematosus (SLE) diagnosed 3 years previously, and treated with hydroxychloroquine and steroids that ceased 6 months before ocular signs. She complained about rapid bilateral blurred vision with a severe loss of visual acuity. Fluorescein angiography found multiple leakage points in the posterior pole of the pigment epithelium. Ocular coherence tomography (OCT) and fundoscopy showed bilateral retinal detachments. Lupus choroidopathy was diagnosed and high steroids were given intravenously and allowed a rapid improvement. Visual acuity, fundoscopy, retinal angiography and OCT were normalized at 2 months. Choroidopathy is rarely reported in lupus and only about 30 patients are found in the literature.

Influenza-induced acute respiratory distress syndrome during the 2010-2016 seasons: bacterial co-infections and outcomes by virus type and subtype.

OBJECTIVES: We aimed to describe bacterial co-infections and acute respiratory distress (ARDS) outcomes according to influenza type and subtype. METHODS: A retrospective observational study was conducted from 2012 to 2016 in patients admitted to the respiratory intensive care unit (ICU) of Marseille university hospital for influenza-induced ARDS. Microbiological investigations, including multiplex molecular respiratory panel testing and conventional bacteriological cultures, were performed as part of the routine ICU care on the bronchoalveloar lavage collected at admission. Bacterial co-infections, ICU mortality and respiratory function were investigated according to virus type and subtype. RESULTS: Among the 45 ARDS patients included, A(H1N1)pdm09 was the most frequent influenza virus identified (28/45 A(H1N1)pdm09, eight out of 45 A(H3N2) and nine out of 45 influenza B). Bacterial co-infections involving a total of 23 bacteria were diagnosed in 16/45 patients (36%). A(H1N1)pdm09 patients presented fewer bacterial co-infections (17.9% vs. 50.0% for A(H3N2) patients and 77.8% for B patients; p < 0.01). Overall, mortality at 90 days post admission was 33.3% (15/45), and there was no significant difference between influenza type and subtype. The need for extracorporeal membrane oxygenation was more frequent for A(H1N1)pdm2009 (20/28, 71.4%) and B patients (7/9, 77.8%) than the A(H3N2) subtype (1/8, 12.5%; p < 0.01). A(H1N1)pdm09-ARDS patients were associated with fewer ventilation-free days at day 28 (median (IQR): 0 (0-8) days) compared with other influenza-ARDS patients (15 (0-25) days, p < 0.05). DISCUSSION: In a population of influenza-induced ARDS, A(H1N1)pdm09 was associated with fewer bacterial co-infections but poorer respiratory outcomes. These data underline the major role of A(H1N1)pdm09 subtype on influenza disease severity.

Influence of infection control report cards on patients' choice of hospital: pilot survey.

The impact on patients' attitudes of quality report cards on infection control in hospitals has never previously been studied. In 2006, the French government implemented a mandatory report card on infection control activity (ICALIN) in all hospitals. This approach was aimed at encouraging professionals to change their routine practices in case they should lose patients due to a low ICALIN score. Our objective was to assess what impact ICALIN could have on patients' attitude as regards hospital choice. We performed a survey of patients and visitors in 14 randomly selected hospitals of various ICALIN scores. A convenience sample of 381 patients and visitors completed an anonymous questionnaire on ICALIN, their reasons for choosing a hospital and attitude in the event of a low ICALIN score. Factors associated with interest in ICALIN and impact of ICALIN on hospital choice were assessed by logistic regression. Our results showed that 77% of participants were interested in ICALIN. ICALIN was ranked sixth as a reason for choosing a hospital. In the case of a low ICALIN, 24.1% of participants would refuse admission and 54.9% would seek advice from their general practitioner. Sociodemographic factors had no influence on patients' attitude. In conclusion, our survey suggests that patients take note of poor performance on infection control report cards. As most patients rely on their general practitioner to interpret these report cards, there is a definite need for further communication with general practitioners on this issue.

Grimontia hollisae, a potential agent of gastroenteritis and bacteraemia in the Mediterranean area.

Vibrio hollisae was first described in 1982 as an agent of diarrhoea and was reclassified in 2003 into a novel genus as Grimontia hollisae. We report the first case of G. hollisae bacteraemia in the Mediterranean area, in an 81-year-old man with a severe gastroenteritis and hepatitis following the consumption of raw oysters. The incidence of this micro-organism as an agent of gastroenteritis may be underestimated because it may not be detected using routine culture conditions.

Epidemiology of respiratory pathogen carriage in the homeless population within two shelters in Marseille, France, 2015-2017: cross sectional 1-day surveys.

OBJECTIVES: To assess risk factors for respiratory tract infection symptoms and signs in sheltered homeless people in Marseille during the winter season, including pathogen carriage. METHODS: Data on 479 male participants within two shelters who completed questionnaires and a total of 950 nasal and pharyngeal samples were collected during the winters of 2015-2017. Respiratory pathogen carriage including seven viruses and four bacteria was assessed by quantitative PCR. RESULTS: The homeless population was characterized by a majority of individuals of North African origin (300/479, 62.6%) with a relatively high prevalence of chronic homelessness (175/465, 37.6%). We found a high prevalence of respiratory symptoms and signs (168/476, 35.3%), a very high prevalence of bacterial carriage (313/477, 65.6%), especially Haemophilus influenzae (280/477, 58.7%), and a lower prevalence of virus carriage (51/473, 10.8%) with human rhinovirus being the most frequent (25/473, 5.3%). Differences were observed between the microbial communities of the nose and throat. Duration of homelessness (odds ratio (OR) 1.77, p 0.017), chronic respiratory diseases (OR 5.27, p <0.0001) and visiting countries of origin for migrants (OR 1.68, p 0.035) were identified as independent risk factors for respiratory symptoms and signs. A strong association between virus (OR 2.40, p 0.012) or Streptococcus pneumoniae (OR 2.32, p 0.014) carriage and respiratory symptoms and signs was also found. CONCLUSIONS: These findings allowed identification of the individuals at higher risk for contracting respiratory tract infections to better target preventive measures aimed at limiting the transmission of these diseases in this setting.

'Bittarella massiliensis' gen. nov., sp. nov. isolated by culturomics from the gut of a healthy 28-year-old man.

We report here the main features of the proposed new bacterial genus Bittarella. The type strain 'Bittarella massiliensis' GD6T (CSUR P2149) was isolated from a stool sample from a healthy French man.

Rubeoparvulum massiliense gen. nov., sp. nov., a new bacterial genus isolated from the human gut of a Senegalese infant with severe acute malnutrition.

Rubeoparvulum massiliense strain mt6T was isolated from the gut microbiota of a severely malnourished boy from Senegal and consisted of facultative anaerobic, spore-forming, nonmotile and Gram-negative rods. R. massiliense showed a 92% similarity with the 16S rRNA of Bacillus mannanilyticus. The genome of strain mt6T is 2 843 796 bp long with a 43.75% G+C content. It contains 2735 protein-coding genes and 76 RNA genes, among which are nine rRNA genes.

First case of bone infection caused by Paenibacillus turicensis.

Paenibacillus spp. are bacteria present in the environment but are rarely isolated in humans. Here we report the first case of bone infection caused by Paenibacillus turicensis and a second case of human infection caused by this bacterium.

"Raoultibacter massiliensis" gen. nov., sp. nov., a new bacterium isolated from the human gut of a Saudi Bedouin.

We propose the description of a new bacterial genus and new bacterial species, "Raoultibacter massiliensis," isolated from a faecal specimen of a 19-year-old healthy Saudi Bedouin.

Tropheryma whipplei DNA in bronchoalveolar lavage samples: a case control study.

Tropheryma whipplei, the causative bacterium of Whipple's disease, can cause acute pneumonia. We performed a case-control study including patients with T. whipplei in bronchoalveolar lavages (BALs) and controls in order to compare patients' clinical statuses. We tested T. whipplei PCR from January 2013 to December 2014, in all the 1438 BALs in Marseille, France. Controls were hospitalized in the same unit during the same period and were comparable in age and sex. Eighty-eight BALs (6.1%) were positive for T. whipplei and 58 patients had pneumonia. Sixty-four patients were male with a mean age of 50.5 years. T. whipplei was commonly associated with aspiration pneumonia (18/88 patients compared with 6/88 controls, p 0.01) and was detected as a unique pathogen in nine cases. Overall, no difference was observed regarding immunocompromised status. Nevertheless, the six AIDS-infected patients in the T. whipplei group had a significantly lower CD4 level than the five AIDS-infected patients in the control group (49 vs. 320/mm3, p 0.01); in addition, five patients were treated with tumour necrosis factor alpha inhibitors (including three treated by monocolonal antibodies and two with soluble receptor) compared with none of the controls (p 0.03). Pneumocystis jirovecii was frequently associated with the T. whipplei group (7/88 vs. 0/88 in control group), Pseudomonas aeruginosa was only detected in the control group (8/88). This study adds evidence for a causative role of T. whipplei in pneumonia. In the future, an experimental model of pneumonia induced by T. whipplei will prove its role in pneumonia.

[Diagnosis of infectious lymphadenitis]. / Diagnostic des adénites infectieuses.

Adenitis is a common disorder requesting numerous medical specialties. Etiologies are dominated by viral and bacterial infections, and more rarely parasitic, or by neoplastic and inflammatory diseases. Nevertheless, etiology remains often unknown and invasive tests may be required. On nodal tissue sample, histological examination, culture and polymerase chain reaction (PCR) are realized. PCR has revolutionized the diagnostic approach and consequently, knowledge of infectious lymphadenopathy. Previously, staphylococcus, streptococcus and mycobacterium were the main infectious agents identified in lymph nodes. Since its use, new emergent microorganisms responsible of lymphadenitis have been identified. Bartonella henselae, responsible of cat scratch disease, is to date the infectious agent most often encountered in adenitis. Mycobacterium avium subsp. hominisuis has been recently described as responsible of children lymphadenitis. PCR has become an essential tool in the diagnostic process of infectious lymphadenitis. Here, we propose a literature review on infectious adenitis and we emphasize the diagnostic strategy of adenitis.