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.

Candidemia in patients with prolonged fever in Kashan, Iran

Background and Purpose:

Candida species are considered a common cause of fungal blood stream infections, which are associated with considerable mortality and morbidity rates, especially in the admitted and immunocompromised patients. Despite the increase in new and available antifungal agents, the emergence of resistant strains is growing. Regarding this, the aim of the present study was to assess the fungal epide­miology of candidemia and the antifungal susceptibility patterns against five current antifungal agents among the patients with prolonged fever, who were admitted to Beheshti Educational Hospital, Kashan, Iran.

Materials and Methods:

This cross-sectional study was conducted on 253 hospitalized patients with prolonged fever despite receiving broad-spectrum antibiotic therapy. Blood samples were collected aseptically, and then cultured using an automated blood culture system and conventional broth culture bottle. Candida isolates were identified at species level using morphological and physiological properties and produced color on the CHROMagar Candida. Furthermore, the antifungal susceptibility testing was performed using (CLSI M27-A3 and CLSI M27-S4) broth microdilution methods.

Results:

The most positive cultures were detected by the automated blood culture system. C.albicans (%50) was the most prevalent species, followed by C. glabrata (%40), and C. parapsilosis, (%10) respectively .The mortality rate was high (%60) and most patients with candidemia were admitted to the Intensive Care Unit and Neonatal Intensive Care Unit. All isolates were susceptible to amphotericin B, while the highest resistance belonged to caspofungin.

Conclusion:

In this study, high resistance was reported, especially for caspofungin, which can be regarded as the emergence of caspofungin-resistant strains. Regarding this, the establishment of a surveillance and prevention program for the reduction of the emergence of resistant species is necessary.

Cooperative α-helix formation of β-lactoglobulin induced by sodium n-alkyl sulfates

It is generally assumed that folding intermediates contain partially formed native-like secondary structures. However, if we consider the fact that the conformational stability of the intermediate state is simpler than that of the native state, it would be expected that the secondary structures in a folding intermediate would not necessarily be similar to those of the native state. beta-Lactoglobulin is a predominantly beta-sheet protein, although it has a markedly high intrinsic preference for alpha-helical structure. The formation of non-native alpha-helical intermediate of beta-lactoglobulin was induced by n-alkyl sulfates including sodium octyl sulfate, SOS; sodium decyl sulfate, SDeS; sodium dodecyl sulfate, SDS; and sodium tetradecyl sulfate, STS at special condition. The effect of n-alkyl sulfates on the structure of native beta-lactoglobulin at pH 2 was utilized to investigate the contribution of hydrophobic interactions to the stability of non-native alpha-helical intermediate. The addition of various concentrations of n-alkyl sulfates to the native state of beta-lactoglobulin (pH 2) appears to support the stabilized form of non-native alpha-helical intermediate at pH 2. The m values of the intermediate state of beta-lactoglobulin by SOS, SDeS, SDS and STS showed substantial variation. The enhancement of m values as the stability criterion of non-native alpha-helical intermediate state corresponded with increasing chain length of the cited n-alkyl sulfates. The present results suggest that the folding reaction of beta-lactoglobulin follows a non-hierarchical mechanism and hydrophobic interactions play important roles in stabilizing the non-native alpha-helical intermediate state.