Association Between Mycoplasma Pneumonia and Increased Risk of Ischemic Stroke

Bacterial Pneumonia and Stroke Risk: A Nationwide Longitudinal Followup Study

BACKGROUND

Pneumonia causes significant morbidity and mortality and has been associated with cardiovascular complications. Our study aimed to investigate the incidence of ischemic and hemorrhagic strokes following bacterial pneumonia.

METHODS

Between 1997 and 2012, 10,931 subjects with bacterial pneumonia and 109,310 controls were enrolled from the Taiwan National Health Insurance Research Database, and were followed up to the end of 2013. The risk of stroke was estimated in Cox regression analyses with hazard ratios (HRs) and 95% confidence intervals (CIs).

RESULTS

When compared to the control group, subjects in the bacterial pneumonia group had a higher incidence of developing ischemic stroke (2.7% versus 0.4%, p <0.001) and hemorrhagic stroke (0.7% versus 0.1%, p <0.001). The risk of stroke increases with repeated hospitalizations due to bacterial pneumonia. Across bacterial etiologies, bacterial pneumonia was a significant risk factor among 775 subjects who developed ischemic stroke (HR, 5.72; 95% CI, 4.92-6.65) and 193 subjects who developed hemorrhagic stroke (HR, 5.33; 95% CI, 3.91-7.26).

CONCLUSION

The risks of developing ischemic stroke and hemorrhagic stroke are significant following bacterial pneumonia infection. The risk factors, clinical outcomes, and the disease course should also be profiled to better inform the monitoring of stroke development and the clinical management of bacterial pneumonia patients.

A Multifactorial Case of Stevens-Johnson Syndrome With Atypical Features

Stevens-Johnson syndrome (SJS) is a severe mucocutaneous reaction that has a broad spectrum of causes and risk factors that include medications and other infectious causes such as Mycoplasma. In this case report, a patient with multiple comorbidities that confounded the presentation of Stevens-Johnson syndrome is observed. The patient was a 29-year-old female with a past medical history of recurrent cerebrovascular accident (CVA) who presented for an evaluation of chest pain. After empiric vancomycin was started for suspicion of endocarditis, our patient developed altered mental status, mucositis, and a painful erythematous erosion on her chest concerning for vasculitis, but after treatment and pathological review, it was found to be Stevens-Johnson syndrome. It is important to not forget the wide variety of risk factors for developing Stevens-Johnson syndrome and some of its unique associated presenting symptoms.

Dual arterial thrombosis: A diagnostic enigma

Cold agglutinin disease is a rare cause of arterial thrombosis leading to stroke, commonly encountered against a background of mycoplasma pneumonia infections. A 22-year-old patient presented with acute-onset left hemiplegia preceded by a short history of fever and cough. Magnetic resonance imaging (MRI) showed a right middle cerebral artery infarct. Serially repeated hemoglobin levels showed a progressive drop and peripheral smear showed evidence of hemolysis. Blood drawn for investigations would rapidly clot, suggesting a possibility of cold agglutinin-induced hemolysis. The patient was then worked up for all the possible causes of hemolytic anemia including secondary causes which were all negative except for significant immunoglobulin M mycoplasma levels with elevated cold antibody titers. The patient was then initiated on pulse steroids with azithromycin and doxycycline and hemoglobin levels stabilized. The patient also developed pulmonary thromboembolism which was managed with anticoagulation. The patient made a steady improvement, was discharged, and is on follow-up. Here, we present a unique case of mycoplasma associated cold agglutinin disease causing arterial thrombosis.

Development of a Nomogram for Predicting Refractory Mycoplasma pneumoniae Pneumonia in Children

BACKGROUND

In children, refractory Mycoplasma pneumoniae pneumonia (RMPP) may result in severe complications and high medical costs. There is research on a simple and easy-to-use nomogram for early prediction and timely treatment of RMPP.

METHODS

From December 2018 to June 2021, we retrospectively reviewed medical records of 299 children with Mycoplasma pneumoniae pneumonia (MPP) hospitalized in Tianjin Children's Hospital. According to their clinical manifestations, patients were divided into the RMPP group and the general Mycoplasma pneumoniae pneumonia (GMPP) group. The clinical manifestations, laboratory indicators, and radiological data of the two groups were obtained. Stepwise regression was employed for variable selection of RMPP. The predictive factors selected were used to construct a prediction model which presented with a nomogram. The performance of the prediction model was evaluated by C statistics, calibration curve, and receiver operating characteristic (ROC) curve.

RESULTS

The RMPP group significantly showed a higher proportion of females, longer fever duration, and longer hospital stay than the GMPP group (P < 0.05). Additionally, the RMPP group revealed severe clinical characteristics, including higher incidences of extrapulmonary complications, decreased breath sounds, unilateral pulmonary consolidation >2/3, and plastic bronchitis than the GMPP group (P < 0.05). The RMPP group had higher neutrophil ratio (N%), C-reactive protein (CRP), interleukin-6 (IL-6), lactic dehydrogenase (LDH), and D-dimer than the GMPP group (P < 0.05). Stepwise regression demonstrated that CRP [OR = 1.075 (95% CI: 1.020-1.133), P < 0.001], LDH [OR = 1.015 (95% CI: 1.010-1.020), P < 0.001], and D-dimer [OR = 70.94 (95% CI: 23.861-210.904), P < 0.001] were predictive factors for RMPP, and developed a prediction model of RMPP, which can be visualized and accurately quantified using a nomogram. The nomogram showed good discrimination and calibration. The area under the ROC curve of the nomogram was 0.881, 95% CI (0.843, 0.918) in training cohorts and 0.777, 95% CI (0.661, 0.893) in validation cohorts, respectively.

CONCLUSION

C-reactive protein, LDH, and D-dimer were predictive factors for RMPP. The simple and easy-to-use nomogram assisted us in quantifying the risk for predicting RMPP, and more accurately and conveniently guiding clinicians to recognize RMPP, and contribute to a rational therapeutic choice.

Rare cause of cardioembolic stroke and central retinal artery occlusion

Primary cardiac valve tumours are rare. This is a case report of a 32-year-old non-smoker man with a history of stroke 1 year prior and no other cardiovascular risk factors. The patient was admitted to our acute stroke ward for recurrent left hemiparesis, slurring of speech, facial asymmetry and central retinal artery occlusion. Initial laboratory investigations and ECG were normal. An urgent CT brain showed a large hypodense area at the right frontal, parietal, temporal, occipital region with effaced sulci and right lateral ventricle with midline shift and cerebral oedema in keeping with acute infarction. We proceeded with CT angiography of the cerebral and carotid on the following day, which revealed no evidence of thrombosis, aneurysm or arteriovenous malformation. There were no abnormal beaded vessels to suggest vasculitis. Transthoracic echocardiography revealed a large mobile mass in the left atrium. Meanwhile, MRI cardiac confirmed a large ill-defined mobile solid mass attached to the mitral valve's inferoseptal component suggestive of mitral valve myxoma. This case report highlights the significance of considering a cardiogenic source of emboli in patients with large cerebral infarcts and other cardiac embolic phenomena. Imaging modalities such as echocardiography and cardiac MRI will help detect treatable conditions, such as valvular myxoma and prevent further complications.

Pooled analysis of nuclear acid sequence-based amplification for rapid diagnosis of Mycoplasma pneumoniae infection

Background

Mycoplasma pneumoniae(M pneumoniae) is a common human etiology of respiratory infections. Nuclear acid sequence‐based amplification (NASBA) shows good value for the detection of M pneumoniae that surpasses PCR. However, the optimal detection technology still remains to be identified. The purpose of this meta‐analysis was to systematically evaluate the overall accuracy of NASBA for diagnosing M pneumoniae infections.

Methods

The databases PubMed, Cochrane Library, Google Scholar, CNKI, Wang Fang, and Baidu Scholar were comprehensively searched from their initiation date to December 2017 for NASBA in the diagnosis of M pneumoniae infection. Meta‐DiSc 1.4 statistical software was used to evaluate the sensitivity (SEN), specificity (SPE), negative likelihood ratio (−LR), positive likelihood ratio (+LR), diagnostic odds ratio (DOR), and summary receiver operating characteristic (SROC). RevMan 5.2 statistical software was used for quality evaluation of the included articles. Publication bias was evaluated by funnel plot.

Results

Six articles with high quality, including 10 studies, were finally included in this meta‐analysis. The combined statistics results for the diagnosis of M pneumoniae infection by NASBA were 0.77 (SEN, 95% CI: 0.71 to 0.82); 0.98 (SPE, 95% CI: 0.98 to 0.99); 0.22 (‐LR, 95% CI: 0.13 to 0.39); 50.38 (+ LR, 95% CI: 21.85 to 116.17); 292.72 (DOR, 95% CI: 95.02 to 901.75); and 0.9875 (the area under the curve of SROC).

Conclusion

Nuclear acid sequence‐based amplification is a reliable technique to diagnose M pneumoniae infection. However, whether it can replace PCR and serology need to be further studied.

Stroke Associated With Recent Mycoplasma Pneumoniae Infection: A Systematic Review of Clinical Features and Presumed Pathophysiological Mechanisms

Introduction: An association between Mycoplasma pneumoniae (MP) infection and stroke has been described, especially in children. However, current knowledge on this rare potential cause of stroke is scant. The purpose of this systematic review of all published cases was to help better understand the relationships between recent MP infection and ischemic stroke on a clinical, radiological and pathophysiological perspective.

Material and Methods: A PubMed and Embase search was performed in September 2018 to identify all published cases of stroke occurring within 4 weeks after MP infection.

Results: Twenty-eight patients with ischemic stroke associated with MP infection were identified. Median age was 8 years (range: neonate to 57). The middle cerebral artery territory was involved in 25 (89%) patients. Fifteen (54%) patients had at least one arterial occlusion. Elevated D-dimer and/or fibrinogen was reported in 8 (29%) patients. Four patients had transient anticardiolipin IgM antibodies. Cerebrospinal fluid analysis showed pleocytosis in 7/20 (35%) patients (median: 19 leucocytes/μL, range: 10 to 63) and MP PCR was positive in 3/8 (38%) patients. The etiological work-up was considered inconclusive in 25 (89%) patients. Three (11%) patients died during follow-up, all of early respiratory deterioration. Neurological functional outcome was good in 22/27 (81%) patients.

Conclusion: The association between MP infection and ischemic stroke in children and young adults is rare. Underlying pathogenesis might include hypercoagulability and vasculitis. Most patients achieve a favorable recovery. Whether MP infection could be a long-term risk factor for stroke by promoting atherosclerosis is uncertain and deserves further investigation.

Ticagrelor Reduces Thromboinflammatory Markers in Patients With Pneumonia

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As expected, ticagrelor reduced ex-vivo ADP-induced aggregation in patients with pneumonia compared with placebo.

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Ticagrelor reduced platelet–leukocyte interactions as well as plasma interleukin-6 within 24 h in patients with pneumonia compared with placebo.

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Ticagrelor acutely altered NETosis biomarkers, whereas placebo had no effect.

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Ticagrelor improved lung function and reduced need for supplemental oxygen in patients with pneumonia compared with placebo.

Despite treatment advances for sepsis and pneumonia, significant improvements in outcome have not been realized. Antiplatelet therapy may improve outcome in pneumonia and sepsis. In this study, the authors show that ticagrelor reduced leukocytes with attached platelets as well as the inflammatory biomarker interleukin (IL)-6. Pneumonia patients receiving ticagrelor required less supplemental oxygen and lung function tests trended toward improvement. Disruption of the P2Y₁₂ receptor in a murine model protected against inflammatory response, lung permeability, and mortality. Results indicate a mechanistic link between platelets, leukocytes, and lung injury in settings of pneumonia and sepsis, and suggest possible therapeutic approaches to reduce complications.(Targeting Platelet-Leukocyte Aggregates in Pneumonia With Ticagrelor [XANTHIPPE]; NCT01883869)

Mycoplasma pneumoniae infection presenting as stroke and meningoencephalitis with aortic and subclavian aneurysms without pulmonary involvement

A 39-year-old Philipino man presented with acute onset fever and headache. Neurological examination was normal except for neck stiffness. There was no history of chest pain, cough or breathlessness. Cerebrospinal fluid (CSF) showed a mild increase in protein with normal sugar and lymphocytic pleocytosis. CSF PCR for herpes simplex and varicella zoster virus was negative. He developed acute right haemiplegia a week after hospitalisation. MRI showed acute infarct in the left centrum semiovale. His angiogram showed aneurysm in the left subclavian artery and aortic arch. The mycoplasma antibody test came positive with very high titres, while rest of the workup was negative. He was treated with azithromycin and his symptoms improved completely.

He was asymptomatic on follow-up after a month. His repeat immunoglobulin G mycoplasma antibody titre showed elevation. Mycoplasma infection is a treatable cause of meningoencephalitis and stroke secondary to vasculitis. Arterial aneurysms are known to occur with mycoplasma infection although rare.

Evaluation of variation in coagulation among children with Mycoplasma pneumoniae pneumonia: a case-control study

Objective

Acute organ embolism in children with Mycoplasma pneumoniae pneumonia (MPP) has been reported, but changes in coagulation are unclear. This study aimed to investigate changes in coagulation in children with MPP.

Methods

A total of 185 children with MMP (cases) and 117 healthy children (controls) were recruited. We measured prothrombin time (PT), activated partial thromboplastin time (APTT), thrombin time (TT), and plasma fibrinogen (FIB) and D-dimer levels.

Results

Plasma FIB (3.39 ± 0.96 g/L vs 2.93 ± 0.6 6g/L, t = 4.50) and D-dimer (326.45 ± 95.62mg/L vs 263.93 ± 103.32mg/L, t=5.36) in MPP children were higher than controls and PT (9.54 ± 4.97S vs 11.48 ± 5.96S, t=3.05) and APTT (31.41 ± 12.01S vs 38.38 ± 11.72S, t=4.95) were shorter than controls. FIB, D-dimer, PT, and APTT were not different between the high IgM-titre and low-titre groups. The areas under the receiver operating characteristic curves in cases and controls for plasma FIB and D-dimer levels were 0.654 (95% confidence interval [CI], 0.593–0.716, P = 0.031) and 0.682 (95% CI, 0.619–0.744, P = 0.032), respectively.

Conclusions

Children with MPP have a higher risk of blood coagulation and thrombosis. Controlling these problems should be considered as soon as possible.

Central retinal artery occlusion and cerebral infarction associated with Mycoplasma pneumonia infection in children

Background

Central retinal artery occlusion (CRAO) is an arterial ischemic stroke, rarely occurred in children accompanied with asymptomatic cerebral infarction and almost never involved in severe pneumonia related to Mycoplasma pneumonia infection.

Case presentation

An 8-year-old boy with severe pneumonia related to Mycoplasma pneumonia infection that developed loss of vision in the left eye on the 14^th day. No light perception and no pupillary reaction to light were found in the left eye. The fundus examination revealed a cherry red spot with severe retinal edema at the macular and peripapillary area, and the optic disc was pale in the left eye but normal in the right eye, suggesting CRAO in the left eye. No obvious neurological symptoms and signs were observed on presentation. Magnetic resonance imaging of the brain showed an abnormal signal of the left lentiform nucleus, caudate nucleus and within the temporal lobe, suggesting an acute cerebral infarction. The analysis of cerebrospinal fluid showed an increasing leukocyte count, but no any pathogenic microorganisms were found. His respiratory symptoms disappeared promptly after therapy, and the patient was discharged after 11 days later, but there was no light in the left eye 2 months after discharge.

Conclusion

M. pneumoniae infection could be developed the risk for cerebral ischemic stroke, including CRAO in children with severe pneumonia. CRAO is a devastating ophthalmologic event leading to a severe impairment of vision. Patients treated within about 6 h of vision loss had a better visual outcome after the onset of vision loss.

On the translocation of bacteria and their lipopolysaccharides between blood and peripheral locations in chronic, inflammatory diseases: the central roles of LPS and LPS-induced cell death

We have recently highlighted (and added to) the considerable evidence that blood can contain dormant bacteria. By definition, such bacteria may be resuscitated (and thus proliferate). This may occur under conditions that lead to or exacerbate chronic, inflammatory diseases that are normally considered to lack a microbial component. Bacterial cell wall components, such as the endotoxin lipopolysaccharide (LPS) of Gram-negative strains, are well known as potent inflammatory agents, but should normally be cleared. Thus, their continuing production and replenishment from dormant bacterial reservoirs provides an easy explanation for the continuing, low-grade inflammation (and inflammatory cytokine production) that is characteristic of many such diseases. Although experimental conditions and determinants have varied considerably between investigators, we summarise the evidence that in a great many circumstances LPS can play a central role in all of these processes, including in particular cell death processes that permit translocation between the gut, blood and other tissues. Such localised cell death processes might also contribute strongly to the specific diseases of interest. The bacterial requirement for free iron explains the strong co-existence in these diseases of iron dysregulation, LPS production, and inflammation. Overall this analysis provides an integrative picture, with significant predictive power, that is able to link these processes via the centrality of a dormant blood microbiome that can resuscitate and shed cell wall components.

Incident asthma and Mycoplasma pneumoniae: A nationwide cohort study

BACKGROUND

Previous studies investigating the relationship between Mycoplasma pneumoniae and incident asthma in the general population have been inconclusive.

OBJECTIVE

We conducted a nationwide cohort study to clarify this relationship.

METHODS

Using the National Health Insurance Research Database of Taiwan, we identified 1591 patients with M pneumoniae infection (International Classification of Diseases, Ninth Revision, Clinical Modification code 4830) given diagnoses between 2000 and 2008. We then frequency matched 6364 patients without M pneumoniae infection from the general population according to age, sex, and index year. Cox proportional hazards regression analysis was performed to determine the adjusted hazard ratio (aHR) of the occurrence of asthma in the M pneumoniae cohort compared with that in the non-M pneumoniae cohort.

RESULTS

Regardless of comorbidities and the use of antibiotic or steroid therapies, patients with M pneumonia infection had a higher risk of incident asthma than those without it. The aHR of asthma was 3.35 (95% CI, 2.71-4.15) for the M pneumoniae cohort, with a significantly higher risk when patients were stratified by age, sex, follow-up time, and comorbidities, including allergic rhinitis, atopic dermatitis, or allergic conjunctivitis. Patients with M pneumoniae infection had a higher risk of having early-onset (age, <12 years; aHR, 2.87) and late-onset (age, ≥12 years; aHR, 3.95) asthma. The aHR was also higher within the less than 2-year follow-up in the M pneumoniae cohort (aHR, 4.41; 95% CI, 3.40-5.74) than in the cohort without the infection.

CONCLUSION

This study found that incident cases of early-onset and late-onset asthma are closely related to M pneumoniae infection, even in nonatopic patients.

The Association Between Insomnia and Increased Future Cardiovascular Events: A Nationwide Population-Based Study

OBJECTIVES

Insomnia may increase the risk of cardiovascular disease (CVD), but the reported magnitude of the associations between sleep characteristics and CVD is inconsistent. We investigated the association between insomnia and the risk of developing acute myocardial infarction (AMI) and/or stroke by using a nationwide, population-based cohort database in Taiwan.

METHODS

The analyses were conducted using information from a random sample of 1 million people enrolled in the nationally representative Taiwan National Health Insurance Research Database. A total of 44,080 individuals who were 20 years or older, including 22,040 people who had diagnosis of insomnia during the study period and an age-, sex-, comorbidity-matched group of 22,040 people without insomnia, were enrolled in our study. The study end points were the occurrence of cardiovascular events including AMI or stroke during follow-up.

RESULTS

During a 10-year follow-up, 302 AMI events and 1049 stroke events were identified. The insomnia group had a higher incidence of AMI (2.25 versus 1.08 per 1000 person-years) and stroke (8.01 versus 3.69 per 1000 person-years, p < .001). Cox proportional hazard regression model analysis showed that insomnia was independently associated with a higher risk of future AMI (hazard ratio [HR] = 1.68, 95% confidence interval [CI] = 1.31-2.16, p < .001), stroke (HR = 1.85, 95% CI = 1.62-2.12, p < .001), and the composite event index (HR = 1.81, 95% CI = 1.61-2.05, p < .001), after adjusting for age, sex, and comorbidities.

CONCLUSIONS

Insomnia is associated with an increased risk of future cardiovascular events.

Mycoplasma pneumonia increases the risk of acute coronary syndrome: a nationwide population-based cohort study

BACKGROUND

Studies investigating the epidemiological relationship between Mycoplasma pneumonia (MP) and the subsequent development of acute coronary syndrome (ACS) are scant. We conducted a nationwide longitudinal cohort study in Taiwan to explore whether MP patients are at an increased risk of developing ACS.

METHODS

This study investigated the incidence and risk factors for ACS in 12 152 newly diagnosed MP patients from the Taiwan National Health Insurance Research Database between 2004 and 2011. The control group consisted of 48 600 individuals without MP. The follow-up period ran from the time of initial MP diagnosis to the date of an ACS event, censoring, or 31 December 2011. We analyzed the risk of ACS by using Cox proportional hazard regression models, including variables for sex, age and comorbidities.

RESULTS

The incidence of ACS was higher in MP patients than in comparison cohort (3.08 vs. 2.42 per 1000 person-years). The hazard ratio of developing ACS increased 37% in MP patients compared with that in the comparison cohort after adjustment for covariates. The effect of MP on subsequent ACS development appeared to 12 months after infection.

CONCLUSION

This nationwide study determined that compared with the general population, MP patients exhibited a 37% increase in the risk of subsequently developing ACS. Clinicians should be aware of this risk in MP patients and provide appropriate cardiovascular management in addition to MP treatment.

Individuality, phenotypic differentiation, dormancy and 'persistence' in culturable bacterial systems: commonalities shared by environmental, laboratory, and clinical microbiology

For bacteria, replication mainly involves growth by binary fission. However, in a very great many natural environments there are examples of phenotypically dormant, non-growing cells that do not replicate immediately and that are phenotypically 'nonculturable' on media that normally admit their growth. They thereby evade detection by conventional culture-based methods. Such dormant cells may also be observed in laboratory cultures and in clinical microbiology. They are usually more tolerant to stresses such as antibiotics, and in clinical microbiology they are typically referred to as 'persisters'. Bacterial cultures necessarily share a great deal of relatedness, and inclusive fitness theory implies that there are conceptual evolutionary advantages in trading a variation in growth rate against its mean, equivalent to hedging one's bets. There is much evidence that bacteria exploit this strategy widely. We here bring together data that show the commonality of these phenomena across environmental, laboratory and clinical microbiology. Considerable evidence, using methods similar to those common in environmental microbiology, now suggests that many supposedly non-communicable, chronic and inflammatory diseases are exacerbated (if not indeed largely caused) by the presence of dormant or persistent bacteria (the ability of whose components to cause inflammation is well known). This dormancy (and resuscitation therefrom) often reflects the extent of the availability of free iron. Together, these phenomena can provide a ready explanation for the continuing inflammation common to such chronic diseases and its correlation with iron dysregulation. This implies that measures designed to assess and to inhibit or remove such organisms (or their access to iron) might be of much therapeutic benefit.

Individuality, phenotypic differentiation, dormancy and 'persistence' in culturable bacterial systems: commonalities shared by environmental, laboratory, and clinical microbiology

For bacteria, replication mainly involves growth by binary fission. However, in a very great many natural environments there are examples of phenotypically dormant, non-growing cells that do not replicate immediately and that are phenotypically 'nonculturable' on media that normally admit their growth. They thereby evade detection by conventional culture-based methods. Such dormant cells may also be observed in laboratory cultures and in clinical microbiology. They are usually more tolerant to stresses such as antibiotics, and in clinical microbiology they are typically referred to as 'persisters'. Bacterial cultures necessarily share a great deal of relatedness, and inclusive fitness theory implies that there are conceptual evolutionary advantages in trading a variation in growth rate against its mean, equivalent to hedging one's bets. There is much evidence that bacteria exploit this strategy widely. We here bring together data that show the commonality of these phenomena across environmental, laboratory and clinical microbiology. Considerable evidence, using methods similar to those common in environmental microbiology, now suggests that many supposedly non-communicable, chronic and inflammatory diseases are exacerbated (if not indeed largely caused) by the presence of dormant or persistent bacteria (the ability of whose components to cause inflammation is well known). This dormancy (and resuscitation therefrom) often reflects the extent of the availability of free iron. Together, these phenomena can provide a ready explanation for the continuing inflammation common to such chronic diseases and its correlation with iron dysregulation. This implies that measures designed to assess and to inhibit or remove such organisms (or their access to iron) might be of much therapeutic benefit.

Pneumonia, thrombosis and vascular disease

SUMMARY

An enhanced risk of cardiovascular mortality has been observed after pneumonia. Epidemiological studies have shown that respiratory tract infections are associated with an increased risk of thrombotic-related vascular disease such as myocardial infarction, ischemic stroke and venous thrombosis. Myocardial infarction and stroke have been detected essentially in the early phase of the disease (i.e. within 48 h from hospital admission), with an incidence ranging from as low as 1% to as high as 11%. Age, previous cardiovascular events and high pneumonia severity index were independent predictors of myocardial infarction; clinical predictors of stroke were not identified. Deep venous thrombosis and pulmonary embolism may also occur after pneumonia but incidence and clinical predictors must be defined. The biological plausibility of such an association may be deduced by experimental and clinical studies, showing that lung infection is complicated by platelet aggregation and clotting system activation, as documented by up-regulation of tissue factor and down-regulation of activated protein C. The effect of antithrombotic drugs has been examined in experimental and clinical studies but results are still inconclusive.

Co-morbidities and mortality associated with intracranial bleeds and ischaemic stroke

Stroke is a leading cause of mortality and acquired disability; however, there has been no comprehensive comparison of co-morbid risk factors between different stroke subtypes. The aim of this study was to compare risk factors and mortality for subdural haematoma (SDH), subarachnoid haemorrhage (SAH) and ischaemic and haemorrhagic stroke. We compiled a database of all patients admitted with these conditions to a large teaching hospital in Birmingham, United Kingdom during the period 2000-2007 using the International Classification of Disease (ICD) 10th revision codes. Generalised linear models were constructed to calculate relative risks (RRs) associated with co-morbidities. In total, 4804 patients were admitted with diagnoses of SDH (1004), SAH (807), ischaemic stroke (2579) and haemorrhagic stroke (414). Patients with SDH were less likely to have pneumonia (0.492, 95% CI, 0.330-0.734; p < 0.001), whereas alcohol abuse (4.21, 95% CI, 2.82-6.28; p < 0.001) was more common. In SAH, ischaemic heart disease (0.56, 95% CI, 0.40-0.79; p < 0.001) was less common. As expected, a range of cardiovascular risk factors were associated with ischaemic stroke. Epilepsy was positively associated with ischaemic stroke (1.94, 95% CI, 1.36-2.76; p < 0.001), indicating a role for targeted primary prevention in patients with epilepsy. Five-year survival was lower in ischaemic and haemorrhagic strokes (41% and 40% respectively, vs. 73% in SDH and 64% in SAH; p < 0.001). These findings may guide clinical risk stratification, and improve the prognostic information given to patients.

Increased risk of ischemic stroke in patients with benign paroxysmal positional vertigo: a 9-year follow-up nationwide population study in taiwan

Benign paroxysmal positional vertigo (BPPV) is a common form of vertigo and is characterized by episodic dizziness related to changes in head position relative to gravity. BPPV symptoms can be similar to those of central nervous system vascular diseases. The association between BPPV and ischemic stroke has not yet been investigated. The study cohort consisted of patients who were diagnosed with BPPV at least twice in the previous year as an outpatient or for whom BPPV was the primary diagnosis as an inpatient (n = 4104). An age- and gender-matched sample that excluded patients with a diagnosis of any form of vertigo was selected as the comparison cohort (n = 8397). All cases were followed up from January 1, 2000, to December 31, 2008. The demographic characteristics, medical comorbidities, and use of medications in both groups were investigated using chi-square tests. A stratified analysis of stroke risk factors was performed to determine the hazard ratios of BPPV. During the 9-year follow-up period, 185 of the 4104 (4.5%) subjects with BPPV and 240 of the 8379 (2.9%) subjects without BPPV developed ischemic strokes. The crude hazard ratio of BPPV for developing ischemic strokes was 1.708. After adjusting for stroke risk factors, the risk of developing ischemic strokes in BPPV subjects was 1.415-fold higher than the risk among those without BPPV (confidence interval: 1.162-1.732, p = 0.001). After a subgroup analysis stratified according to stroke risk factors, BPPV remained independently associated with a higher risk of developing future ischemic stroke. We conclude that BPPV is independently associated with a risk of subsequent ischemic stroke. More aggressive control of modifiable risk factors for ischemic strokes should be conducted in patients with BPPV.

Delineation of immunodominant and cytadherence segment(s) of Mycoplasma pneumoniae P1 gene

BACKGROUND

Adhesion of Mycoplasma pneumoniae (M. pneumoniae) to host epithelial cells requires several adhesin proteins like P1, P30 and P116. Among these proteins, P1 protein has been inedited as one of the major adhesin and immunogenic protein present on the attachment organelle of M. pneumoniae. In the present study, we scanned the entire sequence of M. pneumoniae P1 protein to identify the immunodominant and cytadherence region(s). M. pneumoniae P1 gene was synthesized in four segments replacing all the UGA codons to UGG codons. Each of the four purified P1 protein fragment was analyzed for its immunogenicity with anti-M. pneumoniae M129 antibodies (Pab M129) and sera of M. pneumoniae infected patients by western blotting and ELISA. Antibodies were produced against all the P1 protein fragments and these antibodies were used for M. pneumoniae adhesion, M. pneumoniae adhesion inhibition and M. pneumoniae surface exposure assays using HEp-2 cells lines.

RESULTS

Our results show that the immunodominant regions are distributed throughout the entire length of P1 protein, while only the N- and C- terminal region(s) of P1 protein are surface exposed and block cytadhesion to HEp-2 cells, while antibodies to two middle fragments failed to block cytadhesion.

CONCLUSIONS

These results have important implications in designing strategies to block the attachment of M. pneumoniae to epithelial cells, thus preventing the development of atypical pneumonia.

Metformin-inclusive therapy reduces the risk of stroke in patients with diabetes: a 4-year follow-up study

Metformin is a kind of oral hypoglycemic agents commonly prescribed to patients with diabetes mellitus. Although past studies had proven its protective effect on cardiovascular risk and related mortality, the evidence of metformin on stroke prevention was still insufficient and conflicting. Our study randomly selected 14,856 patients with diabetes from the database provided by the Taiwan National Health Research Institute, and 2 cohorts were formulated according to whether metformin was in the prescription record. All cases were followed up for 4 years to track their stroke incidence. As a result, 701 (17.5%) of 3999 diabetic patients had stroke without metformin use, whereas 994 (9.2%) of 10,857 patients had stroke with metformin use. Cox proportional hazard regressions showed that the stroke hazard ratio (HR) of metformin was .383. After adjustment for the patients' age, gender, hypertension, atrial fibrillation, hyperlipidemia, coronary artery disease, and medications including antiplatelets, coumadin, statin, and estrogen use, the HR was still .468. Further stratified analysis revealed that metformin had more protective effect in the patients with higher risk of stroke. Therefore, metformin should be placed in priority when prescribing oral hypoglycemic agents for diabetic patients when considering stroke prevention according to our study.

Oral alendronate use and risk of cancer in postmenopausal women with osteoporosis: A nationwide study

The association between use of oral bisphosphonates and cancer development in elderly women is still uncertain, and previous studies have shown controversial results. We used a nationwide, population-based database to explore the relationship between the use of alendronate, an oral bisphosphonate agent used for the treatment of osteoporosis, and the risk of all malignancies in women with osteoporosis and age over 55 years. In the study group, we included 6906 women with osteoporosis (age, mean ± SD, 73.4 ± 8.4 years) taking oral alendronate, who were selected from a 1,000,000 sample cohort dataset collected between January 1998 and December 2009. Another 20,697 age- and comorbidity-matched women (73.5 ± 8.4 years) without bisphosphonates treatment were included in the control group. No subjects had any history of being diagnosed with cancer before inclusion. We used a log-rank test to analyze the differences in accumulated cancer-free survival rates between these two groups. A Cox proportional-hazard model, adjusted for confounding factors, was used to evaluate the association between alendronate use and the development of all cancer events in postmenopausal women with osteoporosis. During the mean follow-up period of 4.8 years, 821 patients from the study group and 2646 patients from the control group had new cancers. There was no significant difference in cancer incidence between alendronate users and controls (11.9% versus 12.8%, p = 0.054). The person-year incidence of newly-developed cancer in alendronate users and controls was 28.0 and 29.4 per 1000 person-years, respectively. Alendronate use was not associated with increased risk of cancer development in women with osteoporosis (adjusted hazard ratio, 1.05; 95% confidence interval [CI], 0.97-1.13; p = 0.237). However, due to the limited study size and underpowered results, further larger prospective studies or meta-analysis are suggested to further confirm our findings.

An analysis of the link between strokes and soils in the South Carolina coastal plains

The Stroke Belt is a geographical region of the Southeastern United States where resident individuals suffer a disproportionately higher rate of strokes than the rest of the population. While the "buckle" of this Stroke Belt coincides with the Southeastern Coastal Plain region of North and South Carolina and Georgia, there is a paucity of information pinpointing specific causes for this phenomenon. A number of studies posit that an exposure event-potentially microbial in nature-early in life, could be a risk factor. The most likely vector for such an exposure event would be the soils of the Southeastern Coastal Plain region. These soils may have chemical and physical properties which are conducive to the growth and survival of microorganisms which may predispose individuals to stroke. To this aim, we correlated SC stroke mortality data to soil characteristics found in the NRCS SSURGO database. In statewide comparisons, depth to water table (50 to 100 cm, R = 0.62) and soil drainage class (poorly drained, R = 0.59; well drained, R = -0.54) both showed statistically significant relationships with stroke rate. In a 20 county comparison, depth to water table, drainage class, hydric rating (hydric soils, R = 0.56), and pH (very strongly acid, R = 0.66) all showed statistically significant relationships with stroke rate. These data should help direct future research and epidemiology efforts to pinpoint the exact exposure events which predispose individuals to an increased stroke rate.