Predictors of fatality in influenza A virus subtype infections among inpatients in the 2015-2016 season

BACKGROUND

Infection with the influenza A virus can cause severe disease and mortality. The effect of the different subtypes of influenza on morbidity and mortality is not yet known in Turkey. The aim of this study was to describe the predictors of fatality related to influenza A infection among hospitalized patients in Istanbul during the 2015-2016 influenza season, and to detail the differences between infections caused by H3N2 and H1N1.

METHODS

This was a multicenter study performed by the Istanbul Respiratory Infections Study Group of The Turkish Society of Clinical Microbiology and Infectious Diseases (KLİMİK), among patients hospitalized for influenza in Istanbul during the 2015-2016 influenza season.

RESULTS

A total of 222 patients hospitalized with laboratory-confirmed influenza during the 2015-2016 season were included in the study, of whom 25 (11.2%) died. The fatality rate was significantly higher among patients older than 65 years of age and those with chronic heart and kidney diseases (p<0.001), chronic neurological diseases (p=0.009), and malignancies (p=0.021). Thrombocyte counts were lower in those who died than in those who survived (p<0.004). The median alanine aminotransferase, aspartate aminotransferase, lactate dehydrogenase, creatinine phosphokinase, and C-reactive protein levels were higher among fatal cases. In the multivariate analysis for the prediction of fatality, being >65years old (odds ratio (OR) 6.9, 95% confidence interval (CI) 2.07-23.08, p=0.002), being infected with influenza A(H3N2) (OR 4.2, 95% CI 1.27-14.38, p=0.019), and a 1-day delay in antiviral use (OR 1.28, 95% CI 1.01-1.63, p=0.036) were found to be associated with an increased likelihood of fatality.

CONCLUSIONS

The case fatality rate of influenza A(H3N2) was significantly higher than that of influenza A(H1N1). Detection of the infection, allowing the opportunity for the early use of antiviral agents, was found to be important for the prevention of fatality. The vaccination should be prioritized for at-risk groups.

The burden and epidemiology of community-acquired central nervous system infections: a multinational study

Risk assessment of central nervous system (CNS) infection patients is of key importance in predicting likely pathogens. However, data are lacking on the epidemiology globally. We performed a multicenter study to understand the burden of community-acquired CNS (CA-CNS) infections between 2012 and 2014. A total of 2583 patients with CA-CNS infections were included from 37 referral centers in 20 countries. Of these, 477 (18.5%) patients survived with sequelae and 227 (8.8%) died, and 1879 (72.7%) patients were discharged with complete cure. The most frequent infecting pathogens in this study were Streptococcus pneumoniae (n = 206, 8%) and Mycobacterium tuberculosis (n = 152, 5.9%). Varicella zoster virus and Listeria were other common pathogens in the elderly. Although staphylococci and Listeria resulted in frequent infections in immunocompromised patients, cryptococci were leading pathogens in human immunodeficiency virus (HIV)-positive individuals. Among the patients with any proven etiology, 96 (8.9%) patients presented with clinical features of a chronic CNS disease. Neurosyphilis, neurobrucellosis, neuroborreliosis, and CNS tuberculosis had a predilection to present chronic courses. Listeria monocytogenes, Staphylococcus aureus, M. tuberculosis, and S. pneumoniae were the most fatal forms, while sequelae were significantly higher for herpes simplex virus type 1 (p < 0.05 for all). Tackling the high burden of CNS infections globally can only be achieved with effective pneumococcal immunization and strategies to eliminate tuberculosis, and more must be done to improve diagnostic capacity.

Evaluation of tularaemia courses: a multicentre study from Turkey

In this multicentre study, which is the largest case series ever reported, we aimed to describe the features of tularaemia to provide detailed information. We retrospectively included 1034 patients from 41 medical centres. Before the definite diagnosis of tularaemia, tonsillitis (n = 653, 63%) and/or pharyngitis (n = 146, 14%) were the most frequent preliminary diagnoses. The most frequent clinical presentations were oropharyngeal (n = 832, 85.3%), glandular (n = 136, 13.1%) and oculoglandular (n = 105, 10.1%) forms. In 987 patients (95.5%), the lymph nodes were reported to be enlarged, most frequently at the cervical chain jugular (n = 599, 58%), submandibular (n = 401, 39%), and periauricular (n = 55, 5%). Ultrasound imaging showed hyperechoic and hypoechoic patterns (59% and 25%, respectively). Granulomatous inflammation was the most frequent histological finding (56%). The patients were previously given antibiotics for 1176 episodes, mostly with β-lactam/β-lactamase inhibitors (n = 793, 76%). Antituberculosis medications were provided in seven (2%) cases. The patients were given rational antibiotics for tularaemia after the start of symptoms, with a mean of 26.8 ± 37.5 days. Treatment failure was considered to have occurred in 495 patients (48%). The most frequent reasons for failure were the production of suppuration in the lymph nodes after the start of treatment (n = 426, 86.1%), the formation of new lymphadenomegalies under treatment (n = 146, 29.5%), and persisting complaints despite 2 weeks of treatment (n = 77, 15.6%). Fine-needle aspiration was performed in 521 patients (50%) as the most frequent drainage method. In conclusion, tularaemia is a long-lasting but curable disease in this part of the world. However, the treatment strategy still needs optimization.