[Mycoplasma pneumoniaeoutbreak in the Netherlands 2023-2024]. / Mycoplasma pneumoniae-uitbraak in Nederland 2023-2024.

Currently, there is a nationwide outbreak of Mycoplasma pneumoniae infections. M. pneumoniae is a bacterium that can cause atypical pneumonia, especially in children and young adults, and does not respond to the standard antibiotics prescribed for pneumonia. In addition, the bacterium regularly causes extra-pulmonary symptoms. In our hospitals, we have admitted 100 patients (including 20 children) with M. pneumoniae since the fall of 2023, many of which were young and had severe clinical symptoms. It is important to recognize the clinical picture to start effective antibiotic treatment. In this clinical lesson, we will provide two examples of recently admitted patients and discuss the characteristics of all inpatients who have presented to our hospitals during this epidemic. Finally, we pay attention to antibiotic policy and antibiotic resistance.

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.

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.

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.

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.

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.

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.

Dysregulation of serum gamma interferon levels in vascular chronic Q Fever patients provides insights into disease pathogenesis.

A large community outbreak of Q fever occurred in the Netherlands in the period 2007 to 2010. Some of the infected patients developed chronic Q fever, which typically includes pathogen dissemination to predisposed cardiovascular sites, with potentially fatal consequences. To identify the immune mechanisms responsible for ineffective clearance of Coxiella burnetii in patients who developed chronic Q fever, we compared serum concentrations of 47 inflammation-associated markers among patients with acute Q fever, vascular chronic Q fever, and past resolved Q fever. Serum levels of gamma interferon were strongly increased in acute but not in vascular chronic Q fever patients, compared to past resolved Q fever patients. Interleukin-18 levels showed a comparable increase in acute as well as vascular chronic Q fever patients. Additionally, vascular chronic Q fever patients had lower serum levels of gamma interferon-inducible protein 10 (IP-10) and transforming growth factor ß (TGF-ß) than did acute Q fever patients. Serum responses for these and other markers indicate that type I immune responses to C. burnetii are affected in chronic Q fever patients. This may be attributed to an affected immune system in cardiovascular patients, which enables local C. burnetii replication at affected cardiovascular sites.

Allelic imbalance at the HER2/TOP2A locus in breast cancer.

BACKGROUND: Breast cancer is a heterogeneous disease with various histological features and molecular markers. These are utilized for the prediction of clinical outcome and therapeutic decision making. In addition to well established markers such as HER2 overexpression and estrogen and progesterone receptor (ER and PR) status, chromosomal instability is evolving as an important hallmark of cancers. The HER2/TOP2A locus is of great importance in breast cancer. The copy number variability at this locus has been proposed to be a marker for the degree of chromosomal instability. We therefore developed a Single Nucleotide Polymorphism (SNP) assay to evaluate allelic imbalance at the HER2/TOP2A locus in three different entities of primary breast tumors. METHODS: Eleven SNPs were carefully selected and detected by real time PCR using DNA extracted from paired (histologically normal and tumor) paraffin-embedded tissues. Primary breast tumors of 44 patients were included, 15 tumors with HER2 overexpression, 16 triple negative tumors, defined by the absence of HER2 overexpression and a negative ER and PR status and 13 ER and PR positive tumors without HER2 overexpression. As controls, histologically normal breast tissues from 10 patients with no breast tumor were included. RESULTS: Allelic imbalance was observed in 13/15 (87 %) HER2 positive tumors, the remaining 2 being inconclusive. Of the 16 triple negative tumors, 12 (75 %) displayed instability, 3 (19 %) displayed no instability, and 1 was inconclusive. Of the 13 hormone receptor positive tumors, 5 (38 %) displayed allelic imbalance, while 8 did not. CONCLUSIONS: We conclude that the SNP assay is suitable for rapid testing of allelic (im)balance at the HER2/TOP2A locus using paraffin-embedded tissues. Based on allelic imbalance at this locus, both triple negative and ER and PR positive breast tumors can be subcategorized. The clinical relevance of the allelic (im)balance status at the HER2/TOP2A locus in breast cancer is subject of future study. VIRTUAL SLIDES: The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/2086062232155220.

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.

Estimated prevalence of chronic Q fever among Coxiella burnetii seropositive patients with an abdominal aortic/iliac aneurysm or aorto-iliac reconstruction after a large Dutch Q fever outbreak.

OBJECTIVES: The aim of this study was to estimate the seroprevalence of Q fever and prevalence of chronic Q fever in patients with abdominal aortic and/or iliac disease after the Q fever outbreak of 2007-2010 in the Netherlands. METHODS: In November 2009, an ongoing screening program for Q fever was initiated. Patients with abdominal aortic and/or iliac disease were screened for presence of IgM and IgG antibodies to phase I and II antigens of Coxiella burnetii using immunofluorescence assay and presence of C. burnetii DNA in sera and/or vascular wall tissue using polymerase chain reaction (PCR). RESULTS: A total of 770 patients with abdominal aortic and/or iliac disease were screened. Antibodies against C. burnetii were detected in 130 patients (16.9%), of which 40 (30.8%) patients showed a serological profile of chronic Q fever. Three patients presented with acute Q fever, one of which developed to chronic Q fever over time. The number of aneurysm-related acute complications in patients with chronic Q fever was significantly higher compared to patients negative for Q fever (p = 0.013); 9.0% (30/333) vs. 30.0% (6/20). Eight out of 46 patients with past resolved Q fever (8/46, 17.4%) presented with aneurysm-related acute complications (no significant difference). CONCLUSION: The prevalence of chronic Q fever in C. burnetii seropositive patients with abdominal aortic and/or iliac disease living in an epidemic area in the Netherlands is remarkably high (30.8%). Patients with an aneurysm and chronic Q fever present more often with an aneurysm-related acute complication compared to patients without evidence of Q fever infection.

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.

Emergence of methicillin resistance and Panton-Valentine leukocidin positivity in hospital- and community-acquired Staphylococcus aureus infections in Beira, Mozambique.

OBJECTIVES: The objective of this study was to investigate the antibiotic resistance patterns, including methicillin resistance, inducible macrolide-lincosamide-streptogramin B (MLSB ) resistance and Panton-Valentine leukocidin (PVL) toxin gene carriage among hospital-acquired Staphylococcus aureus (HA-SA) and community-acquired S. aureus (CA-SA), in Beira, Mozambique. METHODS: In 2010-2011, two prospective surveillance studies were conducted on post-operative and burn wound infections at the Central Hospital of Beira and on skin and soft tissue abscesses at the São Lucas Health Centre. We cultured pus samples, identified suspected S. aureus isolates and performed antimicrobial susceptibility testing, including detection of MLSB resistance. Real-time polymerase chain reaction was used to detect mecA, Martineau and PVL genes. RESULTS: The prevalence of hospital-acquired methicillin-resistant S. aureus (HA-MRSA) infection among 53 inpatients was 15.1%; the prevalence of community-acquired methicillin-resistant S. aureus (CA-MRSA) infection among 100 outpatients was 1.0%. Inducible MLSB resistance was present in 41.7% and 10.7% of HA-SA and CA-SA isolates, respectively. PVL toxin gene was detected in 81.1% of methicillin-susceptible S. aureus (MSSA) compared with 11.1% of methicillin-resistant S. aureus. CONCLUSIONS: Our study shows, for the first time in Mozambique, the emergence of HA-MRSA. The prevalence of CA-MRSA was low, whereas the rate of PVL toxin gene carriage in MSSA was high. The high rate of inducible MLSB resistance indicates the importance of performing routine D-tests. Overall, our results show the need of strengthening laboratory facilities to provide microbiological data for both directed therapy and surveillance.

Single nucleotide polymorphism (SNP)-based loss of heterozygosity (LOH) testing by real time PCR in patients suspect of myeloproliferative disease.

During tumor development, loss of heterozygosity (LOH) often occurs. When LOH is preceded by an oncogene activating mutation, the mutant allele may be further potentiated if the wild-type allele is lost or inactivated. In myeloproliferative neoplasms (MPN) somatic acquisition of JAK2V617F may be followed by LOH resulting in loss of the wild type allele. The occurrence of LOH in MPN and other proliferative diseases may lead to a further potentiating the mutant allele and thereby increasing morbidity. A real time PCR based SNP profiling assay was developed and validated for LOH detection of the JAK2 region (JAK2LOH). Blood of a cohort of 12 JAK2V617F-positive patients (n=6 25-50% and n=6>50% JAK2V617F) and a cohort of 81 patients suspected of MPN was stored with EDTA and subsequently used for validation. To generate germ-line profiles, non-neoplastic formalin-fixed paraffin-embedded tissue from each patient was analyzed. Results of the SNP assay were compared to those of an established Short Tandem Repeat (STR) assay. Both assays revealed JAK2LOH in 1/6 patients with 25-50% JAK2V617F. In patients with >50% JAK2V617F, JAK2LOH was detected in 6/6 by the SNP assay and 5/6 patients by the STR assay. Of the 81 patients suspected of MPN, 18 patients carried JAK2V617F. Both the SNP and STR assay demonstrated the occurrence of JAK2LOH in 5 of them. In the 63 JAK2V617F-negative patients, no JAK2LOH was observed by SNP and STR analyses. The presented SNP assay reliably detects JAK2LOH and is a fast and easy to perform alternative for STR analyses. We therefore anticipate the SNP approach as a proof of principle for the development of LOH SNP-assays for other clinically relevant LOH loci.

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.

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.

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.

Bordetella holmesii meningitis in a 12-year-old anorectic girl.

We describe a 12-year-old anorectic girl with Bordetella holmesii meningitis, the techniques used for its identification, and minimum inhibitory concentrations of antibiotics for 7 B. Holmesii strains collected in the Netherlands during the past 12 years. B. holmesii meningitis has not been previously reported.