Changes in serum amyloid A, plasma high-density lipoprotein cholesterol and apolipoprotein A-I as useful biomarkers for Mycobacterium tuberculosis infection.

Introduction. In recent years, cholesterol has received interest in the study of infection due to evidence of a relationship between low plasma cholesterol levels and tuberculosis (TB).Hypothesis/Gap Statement. Plasma lipid profiles of serum amyloid A (SAA), apolipoprotein A-I and high-density lipoprotein cholesterol (HDL-C) are biomarkers associated with symptomatic TB patients.Objective. We aimed to evaluate plasma lipid profiles of apolipoprotein A-I, SAA and the size of HDL as biomarkers to diagnose symptomatic TB patients.Methodology. Patients with TB symptoms attending the Instituto Brasileiro para a Investigação da Tuberculose/Fundação José Silveira (IBIT/FJS) between September 2015 and August 2016 for diagnosis of TB were studied. From 129 patients, 97 were classified as pulmonary TB and 32 as negative-bacilloscopy (non-TB group). Medical history, fasting serum and plasma were obtained. Total cholesterol (TC), HDL-C, apolipoprotein A-I and SAA were measured by enzymatic or immunochemical reaction assays. HDL size was measured by laser light-scattering.Results. In TB patients, TC (147.0±37 vs. 168±44 mg dL-1), HDL-C (37±14 vs. 55±18 mg dL-1) and apolipoprotein A-I (102±41 vs. 156±47 mg dL-1) concentrations were lower (P<0.0001), while HDL particle size (10.16±1.02 vs. 9.62±0.67 nm) and SAA levels (280±36 vs. 19±8 mg L-1) were higher (P<0.0001). Using receiver-operating characteristic curve analysis for predicting TB, the cutoff values were <83.85 mg L-1 for SAA (sensitivity=96.88 %, specificity=78.43 %, P<0.0001), >44.50 mg dL-1 for HDL-C (sensitivity=75 %, specificity=72.16 %, P<0.001) and >118.5 mg dL-1 for apolipoprotein A-I (sensitivity=83.83 %, specificity=72.22 %, P<0.001).Conclusion. SAA, HDL-C and apolipoprotein A-I are associated with TB infection and could be used as laboratory biomarkers, especially in patients who are negative for alcohol-acid-resistant bacilli.

Streptococcus agalactiae in Brazil: serotype distribution, virulence determinants and antimicrobial susceptibility.

BACKGROUND: Group B Streptococcus (GBS) remains a major cause of neonatal sepsis and is also associated with invasive and noninvasive infections in pregnant women and non-pregnant adults, elderly and patients with underlying medical conditions. Ten capsular serotypes have been recognized, and determination of their distribution within a specific population or geographical region is important as they are major targets for the development of vaccine strategies. We have evaluated the characteristics of GBS isolates recovered from individuals with infections or colonization by this microorganism, living in different geographic regions of Brazil. METHODS: A total of 434 isolates were identified and serotyped by conventional phenotypic tests. The determination of antimicrobial susceptibility was performed by the disk diffusion method. Genes associated with resistance to erythromycin (ermA, ermB, mefA) and tetracycline (tetK, tetL, tetM, tetO) as well as virulence-associated genes (bac, bca, lmb, scpB) were investigated using PCR. Pulsed-field gel electrophoresis (PFGE) was used to examine the genetic diversity of macrolide-resistant and of a number of selected macrolide-susceptible isolates. RESULTS: Overall, serotypes Ia (27.6%), II (19.1%), Ib (18.7%) and V (13.6%) were the most predominant, followed by serotypes IV (8.1%) and III (6.7%). All the isolates were susceptible to the beta-lactam antimicrobials tested and 97% were resistant to tetracycline. Resistance to erythromycin and clindamycin were found in 4.1% and 3% of the isolates, respectively. Among the resistance genes investigated, tetM (99.3%) and tetO (1.8%) were detected among tetracycline-resistant isolates and ermA (39%) and ermB (27.6%) were found among macrolide-resistant isolates. The lmb and scpB virulence genes were detected in all isolates, while bac and bca were detected in 57 (13.1%) and 237 (54.6%) isolates, respectively. Molecular typing by PFGE showed that resistance to erythromycin was associated with a variety of clones. CONCLUSION: These findings indicate that GBS isolates circulating in Brazil have a variety of phenotypic and genotypic characteristics, and suggest that macrolide-resistant isolates may arise by both clonal spread and independent acquisition of resistance genes.

Burden of group A streptococcal meningitis in Salvador, Brazil: report of 11 years of population-based surveillance.

BACKGROUND: Over recent decades, a resurgence of invasive group A streptococcal (GAS) infections has been observed; GAS remains a rare cause of pyogenic meningitis. We report herein population-based findings of long-term surveillance for GAS meningitis in Salvador, Brazil, and estimate the overall burden of invasive GAS infections. METHODS: From February 1996 to February 2007 we conducted active surveillance for GAS meningitis in the state reference hospital for infectious diseases in Salvador, Brazil. Data on clinical presentation, laboratory records, and outcome were collected through interviews and chart review. GAS isolates were evaluated for antimicrobial susceptibility and emm type. RESULTS: We identified 20 cases of GAS meningitis, which accounted for 0.9% of all culture-proven bacterial meningitis in the study period. The mean annual incidence of GAS meningitis was 0.03 cases per 100,000 population in metropolitan Salvador and peaked in children <1 year of age (0.67 cases per 100,000 population). Among 17 cases with clinical information available, 41% required intensive care unit support and 25% died. Tested isolates were susceptible to penicillin and exhibited large emm type diversity. Based on the incidence of GAS meningitis, we estimate that the annual incidence of GAS infection is 3 cases per 100,000 population in metropolitan Salvador. CONCLUSIONS: Although rare, GAS is a life-threatening cause of bacterial meningitis. Knowledge of the incidence and emm type variability of the disease is necessary for planning immunization strategies.