Dynamics of SARS-CoV-2 RT-PCR positivity and seroprevalence among high-risk healthcare workers and hospital staff.

Staff working in units that were highly exposed to coronavirus disease 2019 were invited to participate in a 6-month study on the carriage and seroprevalence of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). The results from visits on Day 1 and Day 15 show that 41 cases of SARS-CoV-2 infection were confirmed by reverse transcriptase polymerase chain reaction and/or serology in 326 participants (overall infection rate 12.6%). The presence of comorbidities or symptoms at the time of sample collection was a risk factor for infection, but working as a physician/nurse was not a risk factor. Universal screening in high-risk units, irrespective of symptoms, allowed the identification of asymptomatic and potentially contagious infected workers, enabling them to self-isolate for 7 days.

Enteropathogens in paediatric gastroenteritis: comparison of routine diagnostic and molecular methods.

OBJECTIVES: Studies of acute gastroenteritis (AGE) are hampered by the lack of routine diagnostic methods with good sensitivity and specificity. Molecular methods are increasingly used for clinical purposes, but the clinical significance of a positive result remains a challenge. In this study we aimed to compare results of routine diagnostic methods and molecular methods in symptomatic children and asymptomatic controls. METHODS: Patients presenting to the pediatric emergency departments of two university hospitals in Brussels with AGE were recruited prospectively from May 2015 to October 2016; asymptomatic controls were recruited from the same hospitals. Stool analyses were performed for all participants for common pathogenic bacteria (culture), virus (immunochromatography) and parasites (microscopy). Stools were also analysed with the Luminex Gastrointestinal Pathogen Panel, a multiplex-PCR for common enteropathogens. RESULTS: Stools from 178 patients and 165 controls were analysed. An enteropathogen was detected in 62.4% (111/178) of cases when combining the two methods (56.2% (100/178) by Luminex, 42.7% (76/178) with routine methods) and 29.1% (48/165) of controls (24.2% (40/165) by Luminex and 10.3% (17/165) by routine methods). Some pathogens were detected more often with Luminex than with routine methods, such as Salmonella (16.3% (29/178) with Luminex and 3.9% (7/178) with routine method, p < 0.05), whereas others identified by culture methods, such as Campylobacter, Shigella, Yersinia, were missed by Luminex. CONCLUSIONS: Molecular tools seem attractive methods, providing high positivity and a rapid turn-around time for the diagnosis of AGE. However, high rates of positivity in both cases and controls highlight the difficulty in interpreting results. Pathogens missed by Luminex but detected by culture methods raise more questions about the true clinical interest of the technique for our patients.

Contribution of the FilmArray Respiratory Panel in the management of adult and pediatric patients attending the emergency room during 2015-2016 influenza epidemics: An interventional study.

AIM: To evaluate the contribution of a multiplex PCR for respiratory viruses on antibiotic and antiviral prescription, ancillary test prescription, admission and length of stay of patients. METHODS: Two hundred ninety-one adult and pediatric patients visiting the emergency department during the 2015-2016 influenza epidemic were prospectively included and immediately tested 24/7 using the FilmArray Respiratory Panel. The results were communicated to the practitioner in charge as soon as they became available. Clinical and biological data were gathered and analyzed. FINDINGS: Results from the FilmArray Respiratory Panel do not appear to impact admission or antibiotic prescription, with the exception of a lower admission rate for children who tested positive for influenza B. Parameters that account for the clinical decisions evaluated are CRP level, white blood cell count, suspected or proven bacterial infection and, for adult patients only, signs of respiratory distress. Length of stay is also not significantly different between patients with a positive and a negative result. A rapid influenza test result permits a more appropriate prescription of oseltamivir.

Prospective evaluation of diagnostic tools for respiratory viruses in children and adults.

AIM: To compare the performances of molecular and non-molecular tests to diagnose respiratory viral infections and to evaluate the pros and contras of each technique. METHODS: Two hundred ninety-nine respiratory samples were prospectively explored using multiplex molecular techniques (FilmArray Respiratory Panel, Clart Pneumovir), immunological techniques (direct fluorescent assay, lateral flow chromatography) and cell cultures. FINDINGS: Molecular techniques permitted the recovery of up to 50% more respiratory pathogens in comparison to non-molecular methods. FilmArray detected at least 30% more pathogens than Clart Pneumovir which could be explained by the differences in their technical designs. The turnaround time under 2 hours for the FilmArray permitted delivery of results when patients were still in the emergency room.

Relation between broiler and human Campylobacter jejuni strains isolated in Belgium from 2011 to 2013.

AIMS: This study inquires the relationship between Campylobacter jejuni isolated from broiler meat carcasses (n = 97) and human clinical samples (n = 72) in Belgium, from 2011 to 2013. METHODS AND RESULTS: The evaluation of the relation was based on the characteristics determined using multilocus sequence typing (MLST) alone and combined with flagellin gene A restriction fragment length polymorphism (flaA-RFLP) typing, antibiotic microbiological resistance profiling (AMRp), lipooligosaccharide class typing or virulence gene profiling (Vp). Clusters containing both human and broiler meat strains were more common when MLST was used alone, followed by MLST/flaA-RFLP and then by MLST/AMRp. More logical chronologically relations broiler-human were obtained for MLST/flaA-RFLP, then for MLST, and finally for MLST/AMRp: i.e. the isolates would first be detected in the broiler meat and at the same time or later in humans. CONCLUSIONS: In several cases, the C. jejuni strains isolated from the consumed broiler meat and from the campylobacteriosis case had the same profile, according to the used typing methods. The circulating Campylobacter strains appear to have remained the same from 2011 till 2013 in Belgium. SIGNIFICANCE AND IMPACT OF THE STUDY: This study corroborates previously published data from Belgium that suggest a strong correlation between C. jejuni strains isolated from broiler meat and from campylobacteriosis patients.

Meropenem-clavulanate for drug-resistant tuberculosis: a follow-up of relapse-free cases.

BACKGROUND: Extensively drug-resistant tuberculosis (XDR-TB), defined as TB caused by a Mycobacterium strain resistant to at least rifampicin, isoniazid, any fluoroquinolone and one of the injectable anti-tuberculosis drugs, remains a worldwide public health threat. Among repurposed drugs empirically used for XDR-TB cases, carbapenems have been studied in vitro and in animal models, with encouraging results. However, only short-term follow-up data from clinical studies are currently available. OBJECTIVES: To study the long-term follow-up of XDR-TB cases treated with a regimen containing meropenem-clavulanate (M/Clav). DESIGN: Retrospective observational case series study at a single hospital. METHODS: All hospitalised drug-resistant TB patients who received M/Clav as part of their treatment from 2009 to 2016 were included. Demographic and clinical data were extracted from medical records. RESULTS: Eighteen XDR-TB patients were included in the analysis. The successful outcome and mortality rates were respectively 83.3% and 11.1%. No relapses were observed in cured patients after a median follow-up of 4 years. No specific adverse events were attributed to treatment with M/Clav. CONCLUSION: The rate of sustained successful treatment outcome observed here is far higher than the 26% observed in the 2014 World Health Organization XDR-TB cohort, suggesting that carbapenems may be beneficial for the treatment of difficult-to-treat TB cases.

MALDI-TOF MS contribution to the diagnosis of Campylobacter rectus multiple skull base and brain abscesses.

Campylobacter rectus is rarely associated with invasive infection. Both the isolation and the identification requirements of C. rectus are fastidious, probably contributing to an underestimation of its burden. We report the case of a 66-year-old man who developed several skull base and intracerebral abscesses after dental intervention. Campylobacter rectus was isolated from the brain biopsy. Within 45 minutes of reading the bacterial plate, the strain was accurately identified by MALDI-TOF MS. This rapid identification avoided the extra costs and delays present with 16S rRNA gene sequencing and allowed for a rapid confirmation of the adequacy of the empirical antibiotic treatment.

Antibiotic susceptibility profiles among Campylobacter isolates obtained from international travelers between 2007 and 2014.

Campylobacter infection is a common cause of diarrhea among international travelers. We studied antibiotic resistance patterns among Campylobacter isolates obtained from international travelers according to travel destination. Three collections of isolates obtained from international travelers between 2007 and 2014 (Institute of Tropical Medicine, the "Laboratoire Hospitalier Universitaire de Bruxelles "and the Belgian National Reference Centre for Campylobacter) were used. Isolates were tested for minimal inhibitory concentration (MIC) values (E-test macromethod) for fluoroquinolones, macrolides, tetracyclines, amoxicillin-clavulanic acid, and meropenem. Single isolates from 261 travelers were available; median (IQR) age was 25.4 (4-42) years, 85.8% were symptomatic (information for 224 patients available). Overall resistance to ciprofloxacin was 60.9%, ranging from 50.8% in Africa to 75.0% in Asia. Resistance to erythromycin was 4.6%, with the highest rate observed for Southern Asia (15.2%, seven isolates, six of them recovered from patients returning from India). A total of 126 isolates (48.3%) were resistant to tetracycline. No resistance to amoxicillin-clavulanic acid or meropenem was detected. Ciprofloxacin resistance tended to increase over time (53.9% in 2007 versus 72.2% in 2014), erythromycin resistance remained stable (median annual resistance 4.2%). Most (86.2%) ciprofloxacin-resistant isolates had MIC values ≥32 mg/l, and all erythromycin-resistant isolates had MIC values ≥256 mg/l. Co-resistance to ciprofloxacin and erythromycin was observed in 11 (4.2%) isolates, seven of which came from Southern Asia. Among all regions of travel, more than half of Campylobacter isolates were resistant to ciprofloxacin. Overall resistance to erythromycin was below 5% but reached 15.2% in Southern Asia.

Isolation unit for multidrug-resistant tuberculosis patients in a low endemic country, a step towards the World Health Organization End TB Strategy.

Tuberculosis (TB) remains a threat to public health and is the second cause of death due to a single infectious agent after HIV/AIDS. The worldwide distribution of TB is heterogeneous. The incidence is decreasing in most high-income regions, but the situation remains worrying in many parts of the world. The emergence of Mycobacterium tuberculosis strains resistant to key agents used in treatment (rifampin and isoniazid) contributes to TB transmission around the world. To achieve TB elimination, both high and low endemic countries must upscale their efforts to decrease disease transmission and improve cure rates. Management of drug-resistant TB is of particular importance. In this paper, we discuss the different models of care of multidrug-resistant TB (MDR-TB), the ethical considerations and the specific constraints present in high income countries. The management model chosen by the Belgian TB specialists in accordance with public health authorities as well as building of a specific MDR/XDR-TB isolation unit are also discussed.

Feasibility of matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOF MS) networking in university hospitals in Brussels.

The mutualisation of analytical platforms might be used to address rising healthcare costs. Our study aimed to evaluate the feasibility of networking a unique matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOF MS) system for common use in several university hospitals in Brussels, Belgium. During a one-month period, 1,055 successive bacterial isolates from the Brugmann University Hospital were identified on-site using conventional techniques; these same isolates were also identified using a MALDI-TOF MS system at the Porte de Hal Laboratory by sending target plates and identification projects via transportation and the INFECTIO_MALDI software (Infopartner, Nancy, France), respectively. The occurrence of transmission problems (<2 %) and human errors (<1 %) suggested that the system was sufficiently robust to be implemented in a network. With a median time-to-identification of 5 h and 11 min (78 min, min-max: 154-547), MALDI-TOF MS networking always provided a faster identification result than conventional techniques, except when chromogenic culture media and oxidase tests were used (p < 0.0001). However, the limited clinical benefits of the chromogenic culture media do not support their extra cost. Our financial analysis also suggested that MALDI-TOF MS networking could lead to substantial annual cost savings. MALDI-TOF MS networking presents many advantages, and few conventional techniques (optochin and oxidase tests) are required to ensure the same quality in patient care from the distant laboratory. Nevertheless, such networking should not be considered unless there is a reorganisation of workflow, efficient communication between teams, qualified technologists and a reliable IT department and helpdesk to manage potential connectivity problems.

Subtype determination of Blastocystis isolates by matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOF MS).

The pathogenic role of the enteric parasite Blastocystis remains controversial. Recent studies have suggested that various subtypes (STs) found in human samples could be correlated to the presence or absence and variability of clinical manifestations, and that STs can differ with respect to drug sensitivity. Polymerase chain reaction (PCR) techniques used to determine these STs are expensive and are usually restricted to research laboratory settings. This study evaluates the potential application of the inexpensive matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOF MS) technique to discriminate Blastocystis STs. A database of parasitic protein signatures was constructed for five Blastocystis STs, and the reference spectra were challenged with those from 19 axenic cultures of ST1, ST2, ST3, ST4 and ST8 and those from nine xenic liquid cultures of ST3 and ST4. Samples from axenic cultures were prepared using standard formic acid extraction and direct deposition procedures. The reference spectra revealed five distinct spectral profiles, and the database library allowed for discrimination between all of the cultures with reliability indices ranging from 2.038 to greater than 2.8 when an extraction was performed. The direct deposition procedure resulted in greater variability in the discrimination and direct MALDI-TOF MS identification from xenic liquid cultures was effective in 3 out of 9 samples. MALDI-TOF MS proved to be an effective technology for efficiently discriminating Blastocystis STs in axenic cultures.

Impact of rapid microbial identification directly from positive blood cultures using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry on patient management.

For septic patients, delaying the initiation of antimicrobial therapy or choosing an inappropriate antibiotic can considerably worsen their prognosis. This study evaluated the impact of rapid microbial identification (RMI) from positive blood cultures on the management of patients with suspected sepsis. During a 6-month period, RMI by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) was performed for all new episodes of bacteraemia. For each patient, the infectious disease specialist was contacted and questioned about his therapeutic decisions made based on the Gram staining and the RMI. This information was collected to evaluate the number of RMIs that led to a therapeutic change or to a modification of the patient's general management (e.g. fast removal of infected catheters). During the study period, 277 new episodes of bacteraemia were recorded. In 71.12% of the cases, MALDI-TOF MS resulted in a successful RMI (197/277). For adult and paediatric patients, 13.38% (21/157) and 2.50% (1/40) of the RMIs, respectively, resulted in modification of the treatment regimen, according to the survey. In many other cases, the MALDI-TOF MS was a helpful tool for infectious disease specialists because it confirmed suspected cases of contamination, especially in the paediatric population (15/40 RMIs, 37.50%), or suggested complementary diagnostic testing. This study emphasizes the benefits of RMI from positive blood cultures. Although the use of this technique represents an extra cost for the laboratory, RMI using MALDI-TOF MS has been implemented in our daily practice.

Prospective evaluation of Coris Influ-A&B Respi-Strip and of BinaxNOW Influenza A&B assay against viral culture and real-time PCR assay for detection of 2009 pandemic influenza A/H1N1v in Belgian patients.

PURPOSE: Evaluation of the performance of two rapid (15') antigen detection tests (RAT), BinaxNOW Influenza A&B and Coris Influ-A&B Respi-Strip for the detection of A(H1N1)v2009. STUDY DESIGN: Between July 2009 and November 2009, 4105 respiratory specimens from patients with influenza-like illness attending seven public hospitals in Brussels were prospectively examined by two immunochromatographic RAT, followed by viral culture and/or specific real-time RT-PCR. RESULTS: Samples consisted predominantly of nasopharyngeal aspirates (NPA-41%), nasopharyngeal (NPS-37%) and throat swabs (TS-14%). The sensitivity and specificity of Coris RAT and BinaxNOW RAT were 36.6% and 99.7%, and 47% and 98.7% respectively compared to culture; and 33.7% and 99.6%; and 46.5% and 98.8% compared to RT-PCR. Significant differences in sensitivity could be observed when splitting up the samples by sample type and patient's age. NPA gave by far the highest sensitivities: 51.1- 62% for Coris compared to culture and 62.6-78.4% for BinaxNOW. Sensitivities in paediatric NPS varied less between different hospitals (34-41.9%) being still much higher than in adult NPS (11.4-20%). TS resulted in unsatisfactory results: 13% sensitivity in children and 10.5% in adults. CONCLUSIONS: Both RAT showed excellent specificities, but insufficient sensitivities. Consequently, negative results should be confirmed. NPA are clearly superior to NPS orTS, and they stay the sample of choice for viral diagnosis.

Comparison of an in-house method and the commercial Sepsityper™ kit for bacterial identification directly from positive blood culture broths by matrix-assisted laser desorption-ionisation time-of-flight mass spectrometry.

The identification of bacteria directly from positive blood cultures using matrix-assisted laser desorption-ionisation time-of-flight mass spectrometry (MALDI-TOF MS) is a new challenge to microbiologists. However, the protocols previously described are often difficult to implement in routine and comparisons are not always possible due to the variability of interpretative criteria. This study evaluated the analytical and practical performances of an in-house (IH) method, adapted from previous protocols, and the Sepsityper™ kit (Bruker Daltonics, Bremen, Germany). Positive blood cultures from 63 different patients were prospectively evaluated by both methods. To enhance the sensitivity of these methods, lowered cut-offs were assessed and validated on 66 additional samples. The IH method produced 86.4% and 73.7% correct genus and species identifications, respectively, when using the lowered cut-offs of 1.4 and 1.6 for correct genus and species identifications. The Sepsityper™ kit showed similar results (78.0% and 68.4% correct genus and species identification, respectively). However, the IH method is ten-fold less expensive than the commercial option (0.72 vs. 7.45 /analysis) and its turnaround time is approximately 20 min versus the nearly 40 min required for the Sepsityper™ kit, which includes an extraction step. Finally, the IH method was introduced twice-daily in our routine practice.

Transmission of multiple resistant Salmonella Concord from internationally adopted children to their adoptive families and social environment: proposition of guidelines.

Since 2004, an increasing number of multidrug-resistant Salmonella serovar Concord infections have been isolated in Belgium among children adopted from Ethiopia. The patients or their family were interviewed and the isolates were subtyped. Between 2004 and 2009, a total of 39 Salmonella Concord infections were isolated from patients. Thirty-four isolates presented a multidrug resistance including resistance to extended-spectrum cephalosporins. Thirty-six cases involved children and 30 of these were adopted from Ethiopia. One case was due to contact with an adopted child and for the other 5 cases no direct epidemiological link with Ethiopia could be found, although four isolates displayed the same patterns observed on the adoptees' isolates, strongly suggesting a phylogenetic relationship with the Ethiopian isolates. Our study confirmed the emergence in Europe of S. Concord isolates resistant to third-generation cephalosporin among Ethiopian adoptees. We have demonstrated that transmission (intra- and extra familial) can happen even if the frequency seems to be low. The presence and the transmission of such a multidrug-resistant Salmonella infection constitute a major concern, since such strains could jeopardize classical antibiotic therapy in patients at risk. This study provides useful information for parents adopting children and for their family practitioner.

Accuracy of the API Campy system, the Vitek 2 Neisseria-Haemophilus card and matrix-assisted laser desorption ionization time-of-flight mass spectrometry for the identification of Campylobacter and related organisms.

Biochemical identification of Campylobacter and related organisms is not always specific, and may lead to diagnostic errors. The API Campy, the Vitek 2 system and matrix-assisted desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) are commercially available methods that are routinely used for the identification of these microorganisms. In the present study, we used 224 clinical isolates and ten reference strains previously identified by multiple PCR assays, whole cell protein profiling and either DNA-DNA hybridization or sequencing analysis to compare the reliability of these three methods for the identification of Campylobacter and related pathogens. The API Campy accurately identified 94.4% of Campylobacter jejuni ssp. jejuni and 73.8% of Campylobacter coli, but failed to correctly identify 52.3% of other Epsilobacteria. The Vitek 2 Neisseria-Haemophilus card correctly identified most C. jejuni ssp.jejuni (89.6%) and C. coli (87.7%) strains, which account for the majority of campylobacterioses reported in humans, but it failed in the identification of all of the other species. Despite a good identification rate for both C. jejuni ssp. jejuni and C. coli, both methods showed poor sensitivity in the identification of related organisms, and additional tests were frequently needed. In contrast to API Campy and Vitek, MALDI-TOF MS correctly identified 100% of C. coli and C. jejuni strains tested. With an overall sensitivity of 98.3% and a short response time, this technology appears to be a reliable and promising method for the routine identification of Campylobacter and other Epsilobacteria.

Mathematical model for the control of nosocomial norovirus.

A gastroenteritis outbreak in a long-term care facility was analysed by means of a SEIR (Susceptible, Exposed/Latent phase, Infected/Infectious, and Recovered) compartment model of infection dynamics in a closed population [96 beds; attack rate=41%; R0 (basic reproductive number)=3.74; generation time approximately 1 day; duration of disease approximately 2 days; theoretical infinite (1000 days) duration of hospital stay]. The patient-turnover variation was simulated to determine the effect of the length of hospital stay on the endemic level of gastroenteritis perpetuating the epidemic phase in an open population. With all the other parameters held constant, the prevalence of infected patients in the endemic phase (50 days after the beginning of the outbreak) increased markedly from five to 18 cases as the hospital stay increased from one-tenth of a day (one-day care) to one or two days; the prevalence decreased exponentially with the length of hospital stay, being fewer than five cases for hospital stays >50 days. In conclusion, the endemic prevalence of norovirus gastroenteritis is critically dependent on the patient turnover within hospital wards. For the usual range of hospital stay (0.1-20 days), the prevalence level is sufficiently elevated to maintain the perpetuation of gastroenteritis within the population of institutionalised patients. In long-term care facilities (hospital stay >20 days), the patient turnover is sufficiently low for one to expect a spontaneous extinction of epidemic outbreak without endemic perpetuation. When an epidemic outbreak occurs in an acute-care setting, reinforcement of infection control measures, including closure of the ward, is required to break the transmission chain.

Critical use of nucleic acid amplification techniques to test for Mycobacterium tuberculosis in respiratory tract samples.

The usefulness of employing Belgian selection criteria before performing nucleic acid amplification techniques (NAT) was evaluated. The results of this study show that for smear-negative patients with an abnormal chest radiology result in the absence of a respiratory tract infection by bacterial pathogens, testing with NAT is of major benefit.

Evaluation of the ProSpecT Microplate Assay for detection of Campylobacter: a routine laboratory perspective.

OBJECTIVES: To evaluate the use of the new enzyme-linked immunosorbent assay, the ProSpecT Campylobacter Microplate Assay (Alexon-Trend, Minneapolis, MN, USA), which allows 2-h detection of both Campylobacter jejuni and Campylobacter coli antigen directly in stool specimens. METHODS: Over 4 months, all stool samples preserved in Cary-Blair medium, or fresh specimens, from non-hospitalized children and HIV-infected patients (adults and children), submitted to our laboratory were evaluated with the ProSpecT Campylobacter Microplate Assay. Results were compared with those obtained by routine culture methods using both a specific medium and a filtration method for the recovery of Campylobacter spp. RESULTS: Of the 1205 stool specimens cultured, 101 were found to be positive for either C. jejuni or C. coli, giving an overall recovery rate of 8.38%. Ninety samples were positive by both culture and ProSpecT Campylobacter Microplate Assay, and 11 were positive by culture only, giving a sensitivity of 89.1%. In addition, of 1104 samples negative by culture, 25 were initially positive by ProSpecT Campylobacter Microplate Assay. We found no cross-reaction with other bacterial enteropathogens isolated from stool specimens. These results thus confirm a high specificity (97.7%) for both C. jejuni and C. coli. The positive and negative predictive values found were 78.3% and 99%, respectively. There was no statistically significant difference in sensitivity and specificity if the stool was fresh or preserved with Cary-Blair medium. CONCLUSION: These data suggest that the ProSpecT Campylobacter Microplate Assay is a rapid and easy-to-use test for the detection of both C. jejuni and C. coli in stool specimens. It could be used for patients for whom early antibiotic therapy is needed or for epidemiologic studies.