Comparison of culture-dependent and -independent bacterial detection results on nasal swabs in dogs with nasal discharge.

OBJECTIVES: The role of bacterial communities in the pathophysiology of canine nasal disease is still unclear. How and when to treat dogs with suspected secondary bacterial rhinitis and on which test to rely before making a decision to treat with antimicrobials has not been established. The objective is to compare the results of bacterial identification using agar-plate cultures and 16S rRNA gene amplicon sequencing in dogs with nasal discharge suspected to be of bacterial origin. MATERIALS AND METHODS: Twenty-nine client-owned dogs presented for investigation of nasal disease were included in the study. Paired swabs were collected from the same affected nasal cavity. One swab was streaked on 4 agar media (Columbia Blood Agar, MacConkey, Chapman and Edward's). The other swab was stored in a sterile cryotube at -80°. Extracted DNA underwent a polymerase chain reaction targeting the V1-V3 region of the 16S rRNA gene. RESULTS: At least one of the species detected by amplicon sequencing with a relative abundance of >10% was also identified by culture in 14 cases (48.3%), in association with marked predominance of one taxon (>80% relative abundance) in six of 14 cases. In 12 dogs (41.4%), the cultured isolates were rare or undetected components of the corresponding sequence libraries. A negative culture in the face of bacterial predominance (>50% relative abundance) of a potentially pathogenic bacteria detected by sequencing occurred in 17% (n=5) of cases; however, the use of other agar media may have decreased this percentage. CLINICAL SIGNIFICANCE: Standard culture does not reliably predict the bacterial profile detected by 16S rRNA gene amplicon sequencing.

[The COVID-19 breaker : PCR to the rescue !] / La déferlante COVID-19 : la PCR à la rescousse ! Chronique d'une gestion de crise au Laboratoire de Microbiologie clinique du CHU de Liège.

Chronicle of a crisis management at the Clinical Microbiology Laboratory of CHU Liège The SARS-CoV-2 outbreak in December 2019 in China and its expansion across the world and Europe have requested the participation of clinical laboratories as major players in the diagnosis of COVID-19, to perform PCR tests mainly on nasopharyngeal swabs. In Belgium, the first confirmed COVID-19 patient was diagnosed in early February, the first of many, especially travelers returning from winter sports. In order to meet the ever-increasing demands for testing, the Clinical Microbiology Laboratory of the CHU of Liege had to adapt to this situation: firstly, by developing manual PCR tests and then automated solutions, permitting to increase the number of analyzes by ensuring a short turnaround time of results. Then, a system for the communication of results on a large scale has been set up, and finally solutions to deal with the lack of sampling devices have been found. This first wave of the pandemic has also highlighted an unprecedented solidarity within the institution. In this article, we recount the chronology of the management of this unprecedented health crisis within the Clinical Microbiology Laboratory of the CHU of Liege.

L'émergence du virus SARS-CoV-2 en décembre 2019 en Chine et son expansion à travers le monde et l'Europe ont sollicité la participation des laboratoires de Biologie clinique en tant qu'acteurs majeurs dans le diagnostic de la COVID-19, via la réalisation de tests PCR principalement sur des prélèvements nasopharyngés. En Belgique, le premier patient confirmé COVID-19 a été diagnostiqué début février, avant d'être suivi par de nombreux cas d'infections, initialement chez des vacanciers revenant des sports d'hiver. Afin de répondre à l'augmentation du nombre de tests, le laboratoire de Microbiologie clinique du CHU de Liège a dû s'adapter en développant des tests PCR, d'abord manuels puis automatisés. Ceux-ci ont permis d'augmenter le nombre d'analyses, tout en garantissant un temps de rendu des résultats court, en mettant en place un système de communication des résultats à grande échelle et en trouvant des solutions pour faire face à la pénurie des dispositifs de prélèvement. Cette première vague de la pandémie a aussi révélé une solidarité sans précédent au sein de l'institution. Dans cet article, nous retraçons la chronologie de la gestion de cette crise sanitaire inédite au sein du laboratoire de Microbiologie clinique du CHU de Liège.

[Campylobacter jejuni meningitis]. / Méningite à Campylobacter jejuni.

Cases of Campylobacter jejuni meningitis are extremely rare. In the literature, less than ten cases have been described so far, although Campylobacter spp is one of the most common pathogens causing gastroenteritis in the world. Some common stigmata can be found across these cases such as rupture of the blood-brain barrier, immunosuppression, as well as the tropism of Camplylobacter jejuni for neurological parenchyma. Campylobacter jejuni bacteremia is certainly underestimated because Campylobacter is a thermophilic bacterium and special conditions are required to isolate this organism in blood cultures. PCR is thus an interesting alternative technique for diagnosis. In our case, a patient with a history of resected astrocytoma, had undergone treatment with chemotherapy and radiotherapy because of anaplastic transformation. The patient was admitted with gastroenteritis and Campylobacter jejuni meningitis. The diagnosis was obtained initially on stool cultures and then by PCR of cerebrospinal fluid. The evolution was favorable with meropenem.

Les cas de méningite à Campylobacter jejuni restent extrêmement rares. Dans la littérature, on décrit moins de 10 cas à ce jour, alors que l'infection à Campylobacter est cependant l'une des causes les plus répandues de gastro-entérite dans le monde. Le point commun de tous ces cas de méningite rapportés semble être la fragilité de la barrière hémato-encéphalique et l'immunodépression, ainsi que le tropisme du Campylobacter jejuni pour les tissus neuronaux. La bactériémie à Campylobacter jejuni est par ailleurs sous-estimée car le germe est thermophilique et des conditions particulières sont nécessaires pour isoler cet organisme dans les hémocultures. La PCR est une alternative intéressante pour le diagnostic microbiologique. Dans le cas décrit, le patient présentait des antécédents d'astrocytome pariéto-temporal droit opéré, avec une transformation anaplasique ayant bénéficié de chimio- et radiothérapie concomitantes. Le patient a été admis avec une gastro-entérite compliquée d'une méningite à Campylobacter jejuni. Le diagnostic a été posé initialement sur la coproculture et ensuite par la PCR du liquide céphalo-rachidien. L'évolution a été favorable sous méropénem.

[Endocarditis of mitral and aortic prosthetic heart valves caused by Aggregatibacter aphrophilus]. / Le cas clinique du mois. Endocardite à Aggregatibacter aphrophilus sur prothèses valvulaires.

We present the case of an acute endocarditis of mitral and aortic prosthetic heart valves caused by Aggregatibacter aphrophilus (Haemophilus aphrophilus-paraphrophilus). This third report in the literature emphasizes the diagnostic work-up and the role of positron emission tomography combined with computed tomography in this setting. The specificities of endocarditis due to the HACEK group (Haemophilus spp., Aggregatibacter, Cardiobacterium hominis, Eikenella corrodens and Kingella spp.) and the specific microbiological data and therapeutic options pertinent to this germ are discussed.

Nous rapportons la troisième observation clinique de la littérature d'une endocardite sur prothèses mécaniques mitrale et aortique due à l'Aggregatibacter aphrophilus (Haemophilus aphrophilus-paraphrophilus). Le pathogène récemment rebaptisé Aggregatibacter aphrophilus fait partie du groupe HACEK (Haemophilus spp., Aggregatibacter, Cardiobacterium hominis, Eikenella corrodens and Kingella spp.) impliqué dans des endocardites valvulaires de diagnostic difficile. Cette histoire clinique est l'occasion d'une revue de la littérature et des spécificités de ce pathogène. Elle met en exergue la contribution de la tomographie à émission de positons combinée à une tomodensitométrie dans le diagnostic et le suivi. Elle démontre, avec un recul de plus de deux ans, l'efficacité du traitement médical dans certaines endocardites sur prothèse.

A one-year survey of Microsporum audouinii infections in Belgium: epidemiological and genotypic characterization.

During recent years the proportion of tinea capitis infections due to Microsporum audouinii has increased in both Belgium and other European countries. To better understand the emergence of this species, the Belgian National Reference Centre for dermatophytes launched an epidemiological survey on the main anthropophilic dermatophytes causing tinea capitis in Belgium and included the genomic characterization of M. audouinii isolates. In total, 116 strains of M. audouinii were confirmed and characterized by the DiversiLab(®) system (bioMérieux). Six genotypic variants were identified, among which one major group included 90 isolates and the reference strain. Another variant group (11 strains) was exclusively confined to a geographical region in south Belgium. Analysis of epidemiological characteristics of the infected population showed that the main age category was 5- to 9-year-old children with a sex ratio (male/female) of 1.97. Data concerning the geographic origin of the family revealed a majority of Belgian nationality (44.7%), suggesting that the infection originated in Belgium. Other nationalities were primarily African. At this time, no clear correlation has been established between one particular strain and a specific country of origin.

Satellite lesions accompanying herpes zoster: a new prognostic sign for high-risk zoster.

BACKGROUND: The incidence, clinical relevance and pathogenesis of single, isolated, varicella-like skin lesions occurring far beyond the primary herpes zoster (HZ)-affected dermatome remain unclear. OBJECTIVES: To search prospectively for these satellite lesions in 120 patients with HZ and to correlate their presence with a series of clinical, histological and virological data. METHODS: Relevant clinical data were recorded from 109 patients with proven HZ using immunohistochemistry on Tzanck smears. Furthermore, skin biopsies and blood samples were obtained from a subgroup of patients presenting with primary HZ with and without satellite lesions for histology, immunohistology, serology and real-time polymerase chain reaction. RESULTS: This study identified satellite lesions in 21·1% of the patients with HZ. Their presence conveyed a statistically significant relative risk (RR) for severe (RR 3·27, P < 0·001), multidermatomal (RR 10·6, P < 0·001) and multistage HZ (RR 3·30, P < 0·001); systemic signs (RR 2·08, P = 0·0031); immunosuppression (RR 2·38, P = 0·0014) and hospitalization (RR 2·94, P < 0·001). Varicella zoster virus (VZV) viraemia was higher (mean 4075 copies mL(-1) ) in patients with HZ with satellite lesions than in those without (mean 1466 copies mL(-1) ). In contrast to HZ lesions, satellite lesions often presented positive VZV immunostaining in endothelial cells, suggesting a similar pathogenesis to varicella. A limitation of this study is the centre-linked overrepresentation of immunocompromised patients. CONCLUSIONS: Total-body examination searching for satellite lesions is a rapid, simple and reliable tool for identifying patients with high-risk HZ.

Acute cholecystitis with Listeria monocytogenes.

Listeriosis, an opportunistic food-borne disease caused by Listeria monocytogenes, is infrequent and occurs preferentially in patients at the extremes of age, during pregnancy or in immunocompromised hosts. Most common manifestations are maternofoetal and neonatal infections, severe invasive presentations such as bacteraemia with or without central nervous system symptoms occuring preferentially in immunosuppressed patients and self-limited gastro-enteritis affecting healthy individuals. Exceptionally, focal infections such as cholecystitis are described. We report here a case of acute cholecystitis caused by Listeria monocytogenes in an 82-year-old woman. Thanks to a successful treatment: cholecystectomy and antimicrobial therapy (amoxicillin plus clavulanic acid), the patient soon recovered. This case-report provides an opportunity to review the current literature concerning the association of Listeria monocytogenes and cholecystitis.

[MALDI-TOF mass spectrometry in clinical bacteriology or how to identify a bacteria within one minute]. / Spectrométrie de masse MALDI-TOF en bactériologie clinique ou comment identifier une bactérie en une minute.

The major application of MALDI-TOF mass spectrometry in clinical microbiology is the bacterial identification based on the analysis of all their proteins (ribosomal and membrane-associated proteins). This technology allows the identification of most of bacteria within a few minutes. The method is fast, accurate, reliable and cost-effective by comparison to conventional phenotypic techniques. Other applications of MALDI-TOF mass spectrometry are still under development, as the detection of bacterial toxins or resistance mechanisms to antimicrobial agents.