[Improvement of laboratory diagnostics of cholera due to genetically altered (hybrid) variants of cholera Vibrio biovar El Tor].

AIM: Improvement of laboratory diagnostics of cholera taking into the account appearance of hybrid variants of cholera vibrio El Tor biovar in the 1990s. MATERIALS AND METHODS: Phenotypic and molecular-genetic properties of typical toxigenic (151 strains) and hybrid (102 strains) variants of El Tor biovar cholera vibrios, isolated in the Caucuses in 1970-1990 and 1993-1998, respectively, were studied. Toxigenicity gene DNA fragments, inherent to El Tor biovars or classic, were detected by using a reagent kit "Genes of Vibrio cholerae variant ctxB-rstR-rstC, REF" developed by us. RESULTS: Reagent kit "Genes of V. cholerae variant ctxB-rstR-rstC, REF" is proposed to be used for laboratory diagnostics of cholera during study of material from humans or environmental objects and for identification of V. cholerae 01 on genome level in PCR-analysis as a necessary addition to the classic scheme of bacteriological analysis. CONCLUSION: Laboratory diagnostics of cholera due to genetically altered (hybrid) variants of cholera vibrio El Tor biovar is based on a complex study of material from humans and environmental objects by routine bacteriologic and PCR-analysis methods with the aim of detection of gene DNA fragments in the studied material, that determine biovar (classic or El Tor), identification of V. cholerae O1 strains with differentiation of El Tor vibrios into typical and altered, as well as determination of enterotoxin, produced by the specific cholera vibrio strain (by the presence ctxB(El) or ctxB(Cl) gene DNA fragment, coding biosynthesis of CT-2 or CT-1, respectively).

[Antibacterial susceptibility/resistance of Vibrio cholerae eltor clinical strains isolated in the Caucasus during the seventh cholera pandemic].

The data on antibacterial susceptibility and resistance of Vibrio cholerae eltor phenotypes with different sets of the susceptibility or resistance markers conditioning the outbreaks and sporadic cases of cholera in the Caucasus within 1970-1998 are presented. An increase of the number of the Vibrio cholerae phenotypes resistant to tetracycline and chloramphenicol usually used in the treatment of cholera was recorded in 1990-1994 vs. 1970-1989. The El Tor cholera vibrios stored on synthetic media lost some of their resistance markers, therefore the retrospective investigation of the antibioticograms was only of approximate prognostic value in the choice of the drugs for the etiotropic treatment of cholera in view of possible outbreak of the disease.

[Laboratory diagnostics of acute enteric infections under the conditions of the work of the specialized epidemic brigade during liquidation of the consequences of the emergency situations]. / Laboratornaia diagnostika ostrykh kishechnykh infektsii v usloviiakh raboty spetsializirovannoi protivoépidemicheskoi brigady pri likvidatsii posledstvii chrezvychainykh situatsii.

The scheme of the complex microbiological diagnostics of cholera, dysentery, salmonellosis and escherichiosis has been developed. The scheme includes the introduction of material taken from a patient with acute enteric infection into 1% peptone water (pH 8.0), followed by inoculation into Endo medium (pH 7.4-8.0) and the selection of colonies on MC-agar with the subsequent final identification of bacteria with the use of biochemical, serological and genetic methods of investigation. This scheme is proposed for use in bacteriological sections of specialized antiepidemic brigades working on the liquidation of the consequences of emergency situations when the epidemiological safety of the population is threatened.

[Dynamic signal-averaged ECG during spontaneous stenocardia attacks in patients with ischemic heart disease]. / Dinamika sigtnal-usrednennoi EKG vo vremia spontannykh pristupov stenokardii u bol'nykh ishemicheskoi bolezn'iu serdtsa.

The dynamics of signal-averaged ECG and late potentials was studied in 19 patients with coronary heart disease during spontaneous anginal episodes. Baseline late potentials were observed in 9 (45%) patients, they remaining in all during and after anginal episodes. The occurrence of new late potentials was recorded in none of them. There were no significant differences in some parameters of signal-averaged ECG before, during, and after an anginal episode, though the duration of low-amplitude signals tended to increase at the end of the QRS complex and the mean square amplitude of late 40 msec of QRS complex decreased during transient myocardial ischemia. The differences did not achieve their statistical significance. It was concluded that transient myocardial ischemia during spontaneous anginal episodes failed to lead to the appearance of a substrate for the occurrence of late potentials.

[The effect of transient myocardial ischemia on the late potentials during transluminal coronary angioplasty in patients with ischemic heart disease]. / Vliianie prekhodiashchei ishemii miokarda na pozdnie potentsialy pri transliuminal'noi koronarnoi angioplastike u bol'nykh ishemicheskoi bolezn'iu serdtsa.

The frequency of recording late potentials and their dynamics were studied in 25 patients with coronary heart disease before, during, and after transluminal angioplasty (TAP). Baseline late potentials were observed in 6 (20.7%) cases. During TAP, late potentials were recorded significantly more frequently (48.3%) than the baseline ones (p < 0.03), in 6 (20.7%) patients, late potentials appeared only in arterial dilatation and disappeared after TAP. There was a profound decrease in root-mean-square amplitude of late 40 msec in the QRS complex and an increase in the duration of low-amplitude (less than 40 microV) signals at the end of the QRS complex as compared to the baseline values. In ST-segment elevation, the parameters of the ECG signal-average become deteriorated to a greater degree than those in ST-segment depression.

[The dynamics of the signal-averaged ECG in myocardial infarct patients]. / Dinamika signal-usrednennoi EKG u bol'nykh infarktom miokarda.

To study the dynamics of signal-averaged ECG and late potentials (LP) in the first month of myocardial infarction (MI) and the impact of coronary reperfusion on them, examinations were made of 98 patients with primary myocardial infarction, in 69 of whom coronary reperfusion was achieved. LP was found to be detectable just in the first hours of MI, their stabilization (steady-state appearance or cessation) mainly occurred at day 3 of the onset. LP detection at this time allowed them to be predicted before the patients' discharge (70% sensitivity and 95% specificity, 82% predictive value in the first 24 hours of MI, LPs are characterized by more instability than those in the subsequent period of the patients' hospitalization. Thrombolytic therapy and coronary artery patency have no impact on the frequency of LP recording and parameters of signal-averaged ECG. No significant difference was found in the frequency of recording LP in anterior and inferior MI before discharge. The frequency of LP recording does not depend on the sex and age of a patient, the maximum creatine phosphokinase levels, and the presence of postinfarction angina pectoris and heart failure.