Extracellular DNA of slow growers of mycobacteria and its contribution to biofilm formation and drug tolerance

DNA is basically an intracellular molecule that stores genetic information and carries instructions for growth and reproduction in all cellular organisms. However, in some bacteria, DNA has additional roles outside the cells as extracellular DNA (eDNA), which is an essential component of biofilm formation and hence antibiotic tolerance. Mycobacteria include life-threating human pathogens, most of which are slow growers. However, little is known about the nature of pathogenic mycobacteria’s eDNA. Here we found that eDNA is present in slow-growing mycobacterial pathogens, such as Mycobacterium tuberculosis, M. intracellulare, and M. avium at exponential growth phase. In contrast, eDNA is little in all tested rapid-growing mycobacteria. The physiological impact of disrupted eDNA on slow-growing mycobacteria include reduced pellicle formation, floating biofilm, and enhanced susceptibility to isoniazid and amikacin. Isolation and sequencing of eDNA revealed that it is identical to the genomic DNA in M. tuberculosis and M. intracellulare. In contrast, accumulation of phage DNA in eDNA of M. avium, suggests that the DNA released differs among mycobacterial species. Our data show important functions of eDNA necessary for biofilm formation and drug tolerance in slow-growing mycobacteria.

DIAGNOSTIC VALUE OF THE INTEGRAL HEMATOLOGICAL INDEXES AND CHEMILUMINESCENCE OF NEUTROPHILS IN SEVERE ACUTE PANCREATITIS

Research aim is estimation of dependence between integral hematological indexes and chemiluminescence of neutrophils at severe acute pancreatitis.

MATERIALS AND METHODS

The 70 patients with acute pancreatitis were examined, severity of disease were reviled based on integral score Ranson, results of clinical and laboratories examinations, diagnosis was confirmed by instrumentals methods of diagnostics. Patients were divided into two clinical groups: 35 patients with no severe acute pancreatitis and 35 patients with severe acute pancreatitis. Integral hematological indexes were calculated based on results of clinical blood test. Functional activity of neutrophils were estimated by chemiluminescence analysis, activator of reaction was luminal.

RESULTS

Severe acute pancreatitis was characterized by lowering of intensity chemiluminescence with prevalence hypoxic type of active oxygen's generation 94,28% patients. High negative correlations between integral indexes of inflammatory reaction and degree of endotoxicosis (Kaif - Kalif's leukocytal index of intoxication, index of correlation between neutrophils and lymphocytes, G.D. Dashnayahtsa nuclear index and reactive response of neutrophils) and indexes of chemiluminescence reaction, which show type of active oxygen's generation (intensity of reaction and peak reaction time) were revealed. It allowed talking about high degree of oxidative stress at expressed inflammatory and necrotic process in pancreatic tissue. Decrease of antioxidant resources against a background expressed pathologic process at severe acute pancreatitis was confirmed by High negative correlations between N index of correlation between neutrophils and square under curve of chemiluminescence reaction (-0,62, p=0,001 at spontaneous reaction and -0,72, p=0,001 activated).

[Diagnostic value of integral scoring systems in assessing the severity of acute pancreatitis and patient's condition]

OBJECTIVE

The aim of the study was to evaluate the diagnostic value of specific and nonspecific scoring systems Tolstoy-Krasnogorov score, Ranson, BISAP, Glasgow, MODS 2, APACHE II and CTSI, which used at urgent pancreatology for estimation the severity of acute pancreatitis and status of patient.

METHODS

1550 case reports of patients which had inpatient surgical treatment at Road clinical hospital at the station Krasnoyarsk from 2009 till 2013 were analyzed. Diagnosis of severe acute pancreatitis and its complications were determined based on anamnestic data, physical exami- nation, clinical indexes, ultrasonic examination and computed tomography angiography. Specific and nonspecific scores (scoring system of estimation by Tolstoy-Krasnogorov, Ranson, Glasgow, BISAP, MODS 2, APACHE II, CTSI) were used for estimation the severity of acute pancreatitis and patient's general condition. Effectiveness of these scoring systems was determined based on some parameters: accuracy (Ac), sensitivity (Se), specificity (Sp), positive predictive value (PPV) and negative predictive value (NPV).

RESULTS

Most valuables score for estimation of acute pancreatitis's severity is BISAP (Se--98.10%), for estimation of organ failure--MODS 2 (Sp--100%, PPV--100%) and APACHE II (Sp--100%, PPV--100%), for detection of pancreatonecrosis sings--CTSI (Sp--100%, NPV--100%), for estimation of need for intensive care--MODS 2 (Sp--100%, PPV--100%, NPV--96.29%) and APACHE II (Sp--100%, PPV--100%, NPV--97.21%), for prediction of lethality--MODS 2 (Se-- 100%, Sp--98.14%, NPV--100%) and APACHE II (Se--95.00%, NPV-.99.86%).

CONCLUSION

Most effective scores for estimation of acute pancreatitis's severity are Score of estimation by Tolstoy-Krasnogorov, Ranson, Glasgow and BISAP Scoring systems MODS 2, APACHE I high specificity and positive predictive value allow using it at clinical practice.

An in vivo study of osteoplastic properties of resorbable poly-3-hydroxybutyrate in models of segmental osteotomy and chronic osteomyelitis

A series of 3D implants and filling materials prepared from powdered biodegradable polymers, polyhydroxyalkanoates (PHAs), have been designed for the purposes of reparative osteogenesis. The 3D implants are made of resorbable polymer of hydroxybutyric acid (poly-3-hydroxybutyrate, P3HB) and a composite of this polymer with hydroxyapatite (HA) (P3HB/HA). The properties of the implants were studied in vivo in a model of segmental osteotomy and compared with commercial material Bio-Oss(®). All implants containing P3HB as the main component facilitate reconstructive osteogenesis. P3HB and P3HB/HA show pronounced osteoplastic properties; their in vivo degradation is slow and corresponds to the growth of a new bone tissue, facilitating normal reparative osteogenesis. Also, powdered P3HB and P3HB/tienam can be used as filling materials for osteoplasty of bone cavities infected by Staphylococcus aureus. Biodegradable 3D implants and P3HB-based filling materials show pronounced osteoplastic properties and degrade in vivo at a slow rate, enabling normal reparative osteogenesis.