Community-acquired bacteraemia in COVID-19 in comparison to influenza A and influenza B: a retrospective cohort study.

BACKGROUND: During the coronavirus disease 2019 (COVID-19) pandemic in the Netherlands it was noticed that very few blood cultures from COVID-19 patients turned positive with clinically relevant bacteria. This was particularly evident in comparison to the number of positive blood cultures during previous seasonal epidemics of influenza. This observation raised questions about the occurrence and causative microorganisms of bacteraemia in COVID-19 patients, especially in the perspective of the widely reported overuse of antibiotics and the rising rate of antibiotic resistance. METHODS: We conducted a retrospective cohort study on blood culture results in influenza A, influenza B and COVID-19 patients presenting to two hospitals in the Netherlands. Our main outcome consisted of the percentage of positive blood cultures. The percentage of clinically relevant blood cultures, isolated bacteria and 30-day all-cause mortality served as our secondary outcomes. RESULTS: A total of 1331 viral episodes were analysed in 1324 patients. There was no statistically significant difference (p = 0.47) in overall occurrence of blood culture positivity in COVID-19 patients (9.0, 95% CI 6.8-11.1) in comparison to influenza A (11.4, 95% CI 7.9-14.8) and influenza B patients (10.4, 95% CI 7.1-13.7,). After correcting for the high rate of contamination, the occurrence of clinically relevant bacteraemia in COVID-19 patients amounted to 1.0% (95% CI 0.3-1.8), which was statistically significantly lower (p = 0.04) compared to influenza A patients (4.0, 95% CI 1.9-6.1) and influenza B patients (3.0, 95% CI 1.2-4.9). The most frequently identified bacterial isolates in COVID-19 patients were Escherichia coli (n = 2) and Streptococcus pneumoniae (n = 2). The overall 30-day all-cause mortality for COVID-19 patients was 28.3% (95% CI 24.9-31.7), which was statistically significantly higher (p = <.001) when compared to patients with influenza A (7.1, 95% CI 4.3-9.9) and patients with influenza B (6.4, 95% CI 3.8-9.1). CONCLUSIONS: We report a very low occurrence of community-acquired bacteraemia amongst COVID-19 patients in comparison to influenza patients. These results reinforce current clinical guidelines on antibiotic management in COVID-19, which only advise utilization of antibiotics when a bacterial co-infection is suspected.

Case report: Coxiella burnetii vascular infection and lymphoma in the Netherlands.

OBJECTIVES AND DESIGN: Non-Hodgkin lymphoma has been linked to infection with Coxiella burnetii, potentially through overproduction of IL-10 during infection with C. burnetii. MATERIALS AND METHODS: Description of a case report. RESULTS: We describe a patient with retroperitoneal non-Hodgkin lymphoma and vascular infection with C. burnetii. Immunofluorescence staining and fluorescence in situ hybridization targeting specific C. burnetii 16S rRNA were performed on the retroperitoneal lymphoma tissue sample obtained at diagnosis of NHL. Both were strongly positive for the presence of C. burnetii. CONCLUSIONS: This case provokes questions regarding a potential association between C. burnetii and NHL, and underlines the importance of further exploration of this association.

Outbreak of NDM-1-Producing Klebsiella pneumoniae in a Dutch Hospital, with Interspecies Transfer of the Resistance Plasmid and Unexpected Occurrence in Unrelated Health Care Centers.

In the Netherlands, the number of cases of infection with New Delhi metallo-beta-lactamase (NDM)-positive Enterobacteriaceae is low. Here, we report an outbreak of NDM-1-producing Klebsiella pneumoniae infection in a Dutch hospital with interspecies transfer of the resistance plasmid and unexpected occurrence in other unrelated health care centers (HCCs). Next-generation sequencing was performed on 250 carbapenemase-producing Enterobacteriaceae isolates, including 42 NDM-positive isolates obtained from 29 persons at the outbreak site. Most outbreak isolates were K. pneumoniae (n = 26) and Escherichia coli (n = 11), but 5 isolates comprising three other Enterobacteriaceae species were also cultured. The 26 K. pneumoniae isolates had sequence type 873 (ST873), as did 7 unrelated K. pneumoniae isolates originating from five geographically dispersed HCCs. The 33 ST873 isolates that clustered closely together using whole-genome multilocus sequence typing (wgMLST) carried the same plasmids and had limited differences in the resistome. The 11 E. coli outbreak isolates showed great variety in STs, did not cluster using wgMLST, and showed considerable diversity in resistome and plasmid profiles. The blaNDM-1 gene-carrying plasmid present in the ST873 K. pneumoniae isolates was found in all the other Enterobacteriaceae species cultured at the outbreak location and in a single E. coli isolate from another HCC. We describe a hospital outbreak with an NDM-1-producing K. pneumoniae strain from an unknown source that was also found in patients from five other Dutch HCCs in the same time frame without an epidemiological link. Interspecies transfer of the resistance plasmid was observed in other Enterobacteriaceae species isolated at the outbreak location and in another HCC.

Histological characteristics of the abdominal aortic wall in patients with vascular chronic Q fever.

The aim of this study was to describe specific histological findings of the Coxiella burnetii-infected aneurysmal abdominal aortic wall. Tissue samples of the aneurysmal abdominal aortic wall from seven patients with chronic Q fever and 15 patients without evidence of Q fever infection were analysed and compared. Chronic Q fever was diagnosed using serology and tissue PCR analysis. Histological sections were stained using haematoxylin and eosin staining, Elastica van Gieson staining and immunohistochemical staining for macrophages (CD68), T lymphocytes (CD3), T lymphocyte subsets (CD4 and CD8) and B lymphocytes (CD20). Samples were scored by one pathologist, blinded for Q fever status, using a standard score form. Seven tissue samples from patients with chronic Q fever and 15 tissue samples from patients without Q fever were collected. Four of seven chronic Q fever samples showed a necrotizing granulomatous response of the vascular wall, which was characterized by necrotic core of the arteriosclerotic plaque (P = 0.005) and a presence of high numbers of macrophages in the adventitia (P = 0.007) distributed in typical palisading formation (P = 0.005) and surrounded by the presence of high numbers of T lymphocytes located diffusely in media and adventitia. Necrotizing granulomas are a histological finding in the C. burnetii-infected aneurysmal abdominal aortic wall. Chronic Q fever should be included in the list of infectious diseases with necrotizing granulomatous response, such as tuberculosis, cat scratch disease and syphilis.

Screening of post-mortem tissue donors for Coxiella burnetii infection after large outbreaks of Q fever in The Netherlands.

BACKGROUND: After the largest outbreaks of Q fever ever recorded in history occurred in the Netherlands, concern arose that Coxiella may be transmitted via donated tissues of latent or chronically infected donors. The Dutch Health Council recently advised to screen tissue donors, donating high risk tissues, for Coxiella infection. METHODS: After validation of an enzyme immunoassay (EIA) test for IgG antibodies against phase 2 of C. burnetii for use on post-mortem samples, serum samples of 1033 consecutive Dutch post-mortem tissue donors were tested for IgG antibodies against phase 2 of C. burnetii. Confirmation of reactive results was done by immunofluorescence assay (IFA). All available tissues (corneas, heart valves, skin and bone marrow) from donors with IgG reactivity were tested for presence of Coxiella DNA by PCR. Risk factors for IgG reactivity were investigated. RESULTS: After validation of the tests for use on post-mortem samples, 50/1033 donors (4.8%) screened positive for phase 2 anti-Coxiella IgG by EIA, and 31 were confirmed by IFA (3.0%). One donor showed a serological profile compatible with chronic infection. All tested tissues (25 corneas, 6 heart valves, 4 skin and 3 bone marrow) from donors with IgG reactivity tested negative for the presence of Coxiella DNA. Except for living in a postal code area with a high number of Q fever notifications, no risk factors for IgG reactivity were found. CONCLUSIONS: The strong correlation between notifications and seroprevalence confirms that the used assays are sufficiently specific for use on post-mortem samples, although one has to be aware of differences between batches. Thus, this study provides a validated method for screening tissue donors for infection with Coxiella burnetii that can be used in future outbreaks.

IL-18 serum concentration is markedly elevated in acute EBV infection and can serve as a marker for disease severity.

Epstein Barr virus (EBV)-related diseases encompass both acute infections that result in acute infectious mononucleosis and chronic infections that result in lymphoproliferative malignant diseases. While classical inflammatory parameters such as C-reactive protein (CRP) have proven their usefulness during bacterial and fungal infections, they are often low and nondiscriminatory in viral infections. Here, we show that IL-18 is markedly elevated during acute EBV infections and EBV-associated diseases, while ferritin concentrations are also elevated during acute EBV infection and correlate with IL-18. Therefore, IL-18 and ferritin may represent infection markers for viral infections such as EBV, similar to CRP for bacterial infections.

Identification of risk factors for chronic Q fever, the Netherlands.

Since 2007, the Netherlands has experienced a large Q fever outbreak. To identify and quantify risk factors for development of chronic Q fever after Coxiella burnetii infection, we performed a case-control study. Comorbidity, cardiovascular risk factors, medications, and demographic characteristics from 105 patients with proven (n = 44), probable (n = 28), or possible (n = 33) chronic Q fever were compared with 201 patients who had acute Q fever in 2009 but in whom chronic Q fever did not develop (controls). Independent risk factors for development of proven chronic Q fever were valvular surgery, vascular prosthesis, aneurysm, renal insufficiency, and older age.

Genotypic diversity of Coxiella burnetii in the 2007-2010 Q fever outbreak episodes in The Netherlands.

The genotypic diversity of Coxiella burnetii in clinical samples obtained from the Dutch Q fever outbreak episodes of 2007-2010 was determined by using a 6-locus variable-number tandem repeat analysis panel. The results are consistent with the introduction of one founder genotype that is gradually diversifying over time while spreading throughout The Netherlands.

Epidemic Q fever in humans in the Netherlands.

In 2005, Q fever was diagnosed on two dairy goat farms and 2 years later it emerged in the human population in the south of the Netherlands. From 2007 to 2010, more than 4,000 human cases were notified with an annual seasonal peak. The outbreaks in humans were mainly restricted to the south of the country in an area with intensive dairy goat farming. In the most affected areas, up to 15% of the population may have been infected. The epidemic resulted in a serious burden of disease, with a hospitalisation rate of 20% of notified cases and is expected to result in more cases of chronic Q fever among risk groups in the coming years. The most important risk factor for human Q fever is living close (<5 km) to an infected dairy goat farm. Occupational exposure plays a much smaller role. In 2009 several veterinary control measures were implemented including mandatory vaccination of dairy goats and dairy sheep, improved hygiene measures, and culling of pregnant animals on infected farms. The introduction of these drastic veterinary measures has probably ended the Q fever outbreak, for which the Netherlands was ill-prepared.

Follow-up of 686 patients with acute Q fever and detection of chronic infection.

BACKGROUND: Recent outbreaks in the Netherlands allowed for laboratory follow-up of a large series of patients with acute Q fever and for evaluation of test algorithms to detect chronic Q fever, a condition with considerable morbidity and mortality. METHODS: For 686 patients with acute Q fever, IgG antibodies to Coxiella burnetii were determined using an immunofluorescence assay at 3, 6, and 12 months of follow-up. Polymerase chain reaction (PCR) was performed after 12 months and on earlier serum samples with an IgG phase I antibody titer ≥ 1:1024. RESULTS: In 43% of patients, the IgG phase II antibody titers remained high (≥ 1:1024) at 3, 6, and 12 months of follow-up. Three months after acute Q fever, 14% of the patients had an IgG phase I titer ≥ 1:1024, which became negative later in 81%. IgG phase I antibody titers were rarely higher than phase II titers. Eleven cases of chronic Q fever were identified on the basis of serological profile, PCR results, and clinical presentation. Six of these patients were known to have clinical risk factors at the time of acute Q fever. In a comparison of various serological algorithms, IgG phase I titer ≥ 1:1024 at 6 months had the most favorable sensitivity and positive predictive value for the detection of chronic Q fever. CONCLUSIONS: The wide variation of serological and PCR results during the follow-up of acute Q fever implies that the diagnosis of chronic Q fever, necessitating long-term antibiotic treatment, must be based primarily on clinical grounds. Different serological follow-up strategies are needed for patients with and without known risk factors for chronic Q fever.

Chronic Q fever-related dual-pathogen endocarditis: case series of three patients.

Following Coxiella burnetii infection, there is a 1 to 5% risk of chronic Q fever. Endocarditis, mycotic aneurysm, and vascular prosthesis infection are common manifestations. We present three patients with endocarditis by C. burnetii concomitant with another bacterial pathogen. Chronic Q fever should therefore be considered in all endocarditis patients in regions where Q fever is endemic.

Single-nucleotide-polymorphism genotyping of Coxiella burnetii during a Q fever outbreak in The Netherlands.

Coxiella burnetii is the etiological agent of Q fever. Currently, the Netherlands is facing the largest Q fever epidemic ever, with almost 4,000 notified human cases. Although the presence of a hypervirulent strain is hypothesized, epidemiological evidence, such as the animal reservoir(s) and genotype of the C. burnetii strain(s) involved, is still lacking. We developed a single-nucleotide-polymorphism (SNP) genotyping assay directly applicable to clinical samples. Ten discriminatory SNPs were carefully selected and detected by real-time PCR. SNP genotyping appeared to be highly suitable for discrimination of C. burnetii strains and easy to perform with clinical samples. With this new method, we show that the Dutch outbreak is caused by at least 5 different C. burnetii genotypes. SNP typing of 14 human samples from the outbreak revealed the presence of 3 dissimilar genotypes. Two genotypes were also present in livestock at 9 farms in the outbreak area. SNP analyses of bulk milk from 5 other farms, commercial cow milk, and cow colostrum revealed 2 additional genotypes that were not detected in humans. SNP genotyping data from clinical samples clearly demonstrate that at least 5 different C. burnetii genotypes are involved in the Dutch outbreak.

Rapid HLA-B27 screening with real-time TaqMan PCR: a clinical validation in the Dutch population.

BACKGROUND: Human leukocyte antigen B27 (HLA-B27) is strongly associated with ankylosing spondylitis. The B27 allele is present in 90% of patients with this disease, whereas it is present in only 9% of Caucasians. Molecular detection of HLA-B27 is traditionally based on allele specific amplification of exon 2 (Olerup method) or exon 3 (Dominguez method) by PCR, followed by gel analysis. METHODS: We developed a real-time TaqMan PCR based on the Dominguez method with a ß-Globin PCR as internal control. RESULTS: A total of 544 clinical samples were used to compare the real-time TaqMan PCR with the traditional Dominguez PCR, the traditional Olerup PCR and a commercial Olerup based HLA-B27 detection kit (Olerup SSPTM HLA-B27, GenoVision). While 542 samples gave concordant results, two samples showed discrepancies and were further analyzed. One sample that showed a discrepancy was negative with the traditional Olerup method and positive with the three other procedures. Sequencing analysis showed the presence of HLA-B*2712 in this sample. The other sample, positive with both Olerup based PCRs and negative with both Dominguez based methods, turned out to be positive for HLA-B*2707 by sequence analysis. CONCLUSIONS: With a correct result for 543 out of 544 samples (99.8%), we consider our real-time HLA-B27 PCR is a reliable method to detect HLA-B27 in the Dutch population, with reduced hands-on time and contamination risk compared to traditional PCR methods.

Costs of a clinical pathway with point-of-care testing during influenza epidemic in a Dutch hospital.

Our study aim was to determine how a new clinical pathway, including PCR-based influenza point-of-care test (POCT), influences the hospitalisation costs of patients suspected of influenza presenting at the emergency department of a Dutch hospital during two consecutive influenza epidemics (2016-2017 and 2017-2018). Compared to mean costs per patient of €3661 in 2016-2017, the implementation of this new clinical pathway with influenza POCT in 2017 was associated with mean costs per influenza-positive patient of €2495 in 2017-2018 (P = .3). Our study suggests favourable economic results regarding a new clinical pathway with influenza POCT, reflecting a more efficient care of patients suspected of influenza presenting at the emergency department.

Interlaboratory evaluation of different extraction and real-time PCR methods for detection of Coxiella burnetii DNA in serum.

In the Netherlands, there is an ongoing and unparalleled outbreak of Q fever. Rapid and reliable methods to identify patients infected with Coxiella burnetii, the causative agent of Q fever, are urgently needed. We evaluated the performance of different DNA extraction methods and real-time PCR assays that are in use in seven diagnostic or reference laboratories in the Netherlands. A low degree of variation in the sensitivities of most of the developed real-time PCR assays was observed. However, PCR assays amplifying short DNA fragments yielded better results than those producing large DNA fragments. With regard to DNA extraction, the automated MagNA Pure Compact system and the manual QIAamp DNA mini kit consistently yielded better results than either the MagNA Pure LC system and NucliSens EasyMag (both automated) or the High Pure viral nucleic acid kit (manual). The present study shows that multiple combinations of DNA extraction kits and real-time PCR assays offer equivalent solutions to detect C. burnetii DNA in serum samples from patients suspected to have Q fever.

Septicemia, endocarditis, and cerebral infarction due to Staphylococcus aureus in a harp seal (Phoca groenlandica).

An adult, wild-collected, male harp seal (Phoca groenlandica) was transferred from a rehabilitation center to a display facility because of unilateral phthisis bulbi and decreased use of the right forelimb, which precluded its release. In quarantine, the animal demonstrated limited use of the right forelimb, which acutely progressed to complete disuse of the limb accompanied by intermittent lethargy. One month after transfer, the animal was found dead on exhibit. Necropsy showed septic arthritis of the right scapulohumeral joint, valvular endocarditis with systemic bacterial thromboembolism, and infarction of the cerebrum and myocardium. Culture of the blood and affected joint space revealed Staphylococcus aureus. Bacterial polymerase chain reaction of formalin-fixed tissues from the heart and brain were also positive for S. aureus. Staphylococcus aureus infection should be considered as an additional cause of endocarditis and embolic encephalitis in seals.

Pitfalls of molecular diagnostic testing for Coxiella burnetii DNA on throat swabs.

INTRODUCTION: Coxiella burnetii, the causative pathogen of Q fever, is regularly detected in throat swabs from patients without serological evidence of Q fever infection. C. burnetii is also frequently found in bulk tank milk from dairy cows. We evaluated the false positivity rate of polymerase chain reaction (PCR) for C. burnetii DNA on throat swabs and investigated whether recent consumption of C. burnetii DNA-positive cow milk could contribute to this phenomenon. METHODS: C. burnetii PCR was performed on throat swabs obtained from patients in whom a throat swab was ordered for other diagnostic purposes; patients with community-acquired pneumonia (CAP); and healthy volunteers after consumption of commercial C. burnetii-containing cow milk products. RESULTS: C. burnetii DNA was found in 5.0% of throat swabs ordered for other diagnostic purposes and in 15.3% of throat swabs from CAP patients without serological evidence of Q fever pneumonia. The positive and negative predictive value of C. burnetii PCR on throat swabs for Q fever pneumonia were 66.7% (95% CI, 38.0-88.2) and 48.9% (95% CI, 41.3-54.6), respectively. After consumption of commercial C. burnetii-containing cow milk products, C. burnetii DNA could be detected in throat swabs for as long as 30 min after ingestion. CONCLUSION: C. burnetii PCR on throat swabs is of low diagnostic value for Q fever pneumonia and was false positive in 15.3% of CAP patients without Q fever pneumonia. Recent consumption of C. burnetii-containing products can influence the outcome of C. burnetii PCR on throat swabs. Therefore, diagnosis of C. burnetii infection should be made in combination with serology or PCR performed on blood.

Coxiella burnetii in non-Hodgkin lymphoma tissue samples: Innocent until proven otherwise?

PURPOSE: Coxiella burnetii has been suggested as a potential cause of B-cell non-Hodgkin lymphoma (B-NHL), as C. burnetii was detected in B-NHL tissues. To further investigate this potential relationship, we hypothesized that among subjects previously exposed to C. burnetii, the bacterium is more frequently detectable in tissues of patients with B-NHL (cases) compared to patients without B-NHL (controls). METHODS: We aimed to evaluate this hypothesis by assessing the presence of C. burnetii with polymerase chain reaction (PCR), immunofluorescence staining (IF) and fluorescent in-situ hybridization (FISH). Eligible patients were those previously exposed to C. burnetii. RESULTS: Samples were available for 13 cases and 16 controls. C. burnetii was demonstrated in tissues of 8/29 patients in total (28%), with either PCR, IF or FISH: in 5/13 cases (38%) and 3/16 controls (19%), p = 0.41. Negative and positive control samples were all negative and positive appropriately for all three diagnostic methods. CONCLUSIONS: In patients previously exposed to C. burnetii the bacterium was detected in tissue samples from subjects with and without B-NHL, without significant differences in the proportion positive samples. Therefore, we conclude that detection of C. burnetii in tissues of patients previously exposed to C. burnetii is a non-specific finding.

Disseminated Mycobacterium abscessus infection in a peritoneal dialysis patient.

A disseminated peritoneal dialysis-related Mycobacterium abscessus infection is very rare. M. abscessus belongs to the rapidly growing mycobacteria and can be misidentified as a diphtheroid bacterium, which in our case delayed diagnosis and optimal treatment. Due to intrinsic resistance to most antimicrobials, therapeutic options in M. abscessus infections are limited. Infection often leads to catheter loss. A fatal outcome, like in our case, is not exceptional.