Sensitivity of clinical strains of facultatively anaerobic bacteria to antimicrobial drugs

Six hundred and sixty five samples of clinical materials from patients with various pyoinflammatory diseases were tested for obligatory anaerobes. Anaerobes were detected in 148 samples which amounted to 22.3 per cent of the total number of the samples and to 33.2 per cent of the samples with microbial growth. A total of 171 strains of obligatory anaerobes were isolated. Among them 58.5, 24.5, 16.4 and 0.6 per cent were nonsporulating gramnegative bacilli, grampositive cocci, grampositive bacilli and gramnegative cocci respectively. Sensitivity of the isolated anaerobes was tested with the disk diffusion method. The most active drugs against the tested strains were: nitroxoline, rifampicin, metronidasole, erythromycin, carbenicillin and cefotaxim (4.2, 4.5, 9.3, 10.6, 11.5 and 11.7 per cent of the resistant strains respectively). Gentamicin, polymyxin M, novobiocin and cefazoline were the least active drugs (94.6, 78.9, 65.4 and 50.0 per cent of the resistant strains respectively). Metronidasole, levomycetin, nitroxolin, rifampicin and furazolidone showed the highest activity against bacteroids of the fragilis group (0, 0, 0, 8 and 12.5 per cent of the resistant strains respectively) while gentamicin, polymyxin M, cefazolin, oxacillin, novobiocin and penicillin showed the lowest activity (100, 100, 100, 100, 87.0 and 66.7 per cent of the resistant strains respectively).     

Formation of broad-spectrum antibiotics by cultures of the genus Micromonospora]

Data on the study of antibiotic production by the representatives of Micromonospora and the use of ion exchange resins for intensification of screening antibiotic-producing organisms among Micromonospora are presented. It was found that out of 172 strains of Micromonospora tested 92 (53.5 per cent) cultures produced antibiotics, 18 of which were active against gramnegative bacteria. The use of carboxylic ion exchange resins at early microbiological stages of the screening provided an increase in the frequency of finding broad spectrum antibiotics from 10.4 to 19.7 per cent.     

Rifampicin in the treatment of infections of non-tuberculous etiology

Clinical efficacy of rifampicin, a semisynthetic broad spectrum antibiotic was estimated in 247 patients with purulent inflammations. It was shown advisable to use rifampicin intravenously in treatment of severe bronchopulmonary pathology, disorders of the bile excretion system, osteomyelitis, severe wound infections and in prophylaxis of postoperative purulent complications in cardiovascular surgery and other cases. High rifampicin sensitivity of staphylococci and streptococci belonging to various species was revealed. Rifampicin was found to be less active against gramnegative pathogens. The isolation frequency of rifampicin sensitive strains of E. coli, Proteus spp., Klebsiella spp. and P. aeruginosa amounted to 88.4, 52.1, 58.8 and 49.3 per cent respectively.     

Directed isolation of Micromonospora generic cultures from moist soils and silts

The data on the study of various soils and substrates for isolation of Micromonospora from them are presented. It was shown that Micromonospora predominated in moist soils and especially in such substrates as silts where their content with respect to the all actinomycetous isolates amounted to 88.9 per cent. In the silts the content of Micromonospora amounted to 66.6--83 per cent, in the sopromely its content was 66 per cent, while in the ordinary non-moist soil its content was from 6 to 11 per cent. Predominance of Micromonospora in silts and moist soils makes its directed search possible.     

Results of testing a new method of using antibiotics in nutrient media for the isolation of Shigella: the 2-streak method]

A new variant of media with antibiotics for isolation of Shigella, i.e. a method of 2 streaks each containing different antibiotics was tested in analysis of excrements from patients with acute dysentery. It was found that the new method is more effective than the well known method of gradient plates (isolation of Shigella in one series of the experiments amounted to 85.2 and 64.7 per cent respectively, and in the other series of the experiments the respective figures were 95.4 and 89.3 per cent). Its efficiency was lower as compared to the procedure of inoculation onto 2 plates, i.e. onto the media with and without an antibiotic (isolation of Shigella was 67.5 and 77.4 per cent respectively). The new method provided a higher frequency of Shigella isolation as compared to inoculation onto the media without an antibiotic, as well as onto any of the media used with one antibiotic. The method of 2 streaks offers wider possibilities for choosing the antibiotics for adding to the nutrient medium, as well as estimation of the antibioticograms and species structures of Shigella distributed in a concrete area.     

Isolation and characteristics of the lipid granules of Candida tropicalis yeasts

Preparative isolation of lipid granules from the protoplasts of Candida tropicalis was conducted by a technique of flotation in a stepwise density gradient. Parameters were selected for decomposing the protoplasts under hypotonic and isotonic conditions which made it possible to preserve the lipid granules being isolated intact, as well as parameters of a density gradient and centrifugation. The specific content of lipids, proteins and low molecular weight compounds was assayed using labeled compounds in the lipid granules which were isolated from yeast cells cultivated on various carbon substrates (1-6(-14C)-glucose and 1(-14C-octadecane). The lipid composition of the spherosomes was determined. If the yeast was grown on glucose, lipids localized in the lipid granules were represented mainly by triglycerides whose carbon constituted 69 per cent of the total lipid carbon. If it was cultivated on n-octadecane, these lipids were represented by hydrocarbons (51 per cent) and triglycerides (22 per cent). The structures isolated possessed a small lipase activity. The specific lipase activity of the lipid granules was lower by 16 per cent than that of the cell protoplast.     

Antibiotic sensitivity of pneumonia pathogens in newborns and problems of antibacterial therapy of the pathologic process]

The results of the bacteriological investigation of the secretion from the trachea, large bronchi and fauces of 36 newborns (including 27 preterms) with severe pneumonia were analyzed. 20 of them were born of women with complicating somatic, obstetric and gynecologic histories: candidiasis, herpes genitalis, chronic endometritis, adnexitis or chronic pyelonephritis that could be the risk of the fetus intranatal infection. During the acute period of pneumonia in the newborns within the first 4-8 days of life mainly Pseudomonas aeruginosa was isolated (51.3 per cent), Staphylococcus epidermidis, S. haemolyticus and Enterococcus faecalis were less frequent (18.9, 8.1 and 5.4 per cent, respectively). Klebsiella pneumoniae, Streptococcus anhaemolyticus and other organisms were extremely rare. On the whole the gramnegative microflora predominated. The study of the antibiotic susceptibility showed that the majority of the P. aeruginosa isolates were susceptible to amikacin and polymyxin B, the isolates susceptible to ceftazidime were less frequent, 20-25 per cent of the isolates were susceptible to ciprofloxacin, cefoperazone and imipenem and practically no isolates were susceptible to gentamicin. The S.epidermidis isolates were susceptible to rifampicin and vancomycin and in rare cases to fusidin and amikacin and resistant to oxacillin. When the treatment course was more than 15 days, the isolates proved to be susceptible to 1/3 of the presently available antibiotics. Because of the host low protective forces, peculiarities of the infection pathways and high frequency of the resistant strains it is valid to include netilmicin, imipenem, cefoperazone and ceftriaxone to the complex therapy of the newborns along with the substitution immunotherapy.     

Normal microflora of the pharyngeal mucosa

Aerobic microflora of the throat mucosa was studied in 518 healthy persons aged 1 to 50 years. On the basis of the study results, criteria for estimating microbiocenoses of the upper respiratory tracts were defined. It was shown that the throat symbiotic flora included three groups of microorganisms playing different roles in the development of microbiocenosis. The indigenous group consisted of representatives of Streptococcus and Neisseria and was characterized by permanent (90-100 per cent) and intensive (3-8 lg CFU/ml) colonization, broad species spectrum, associations of 2-3 and more species and no significant influence of sociological, age and season factors. The representatives of the facultative group i.e. bacteria belonging to Staphylococcus, Corynebacterium and Haemophilus were less frequent (25-50 per cent). The intensity of their isolation was lower (1-4 lg CFU/ml) and their species spectrum was narrow. The microorganisms of the transitory group were characterized by low frequency (5-20 per cent) and insignificant contamination of the throat mucosa (1-2 lg CFU/ml). The nature of the colonization was monospecific. The group was more numerous by generic composition (Candida, Escherichia, Klebsiella, Citrobacter, Enterobacter, Pseudomonas, Branhamella, Moraxella and Micrococcus). However, it was generally limited by one colonization type. The facultative and transitory groups were subject to age and season variation. They were also different in urban and rural populations.     

Method of isolating pathogenic enterobacteria from atmospheric air]

The authors present comparative results of determination of sedimentation and aspiration methods of air pollution by pathogenic enterobacteria during the artificial sewage "raining". Results (in per cent) of isolation of salmonellae from the air by both methods proved to be very close; however, a possibility of isolation of pathogenic bacteria from the air increased with the use of the apparatus for the examination of large air volumes.     

Gluconeogenesis in the liver of arthritic rats

The gluconeogenic response in the liver from rats with chronic arthritis to various substrates and the effects of glucagon were investigated. The experimental technique used was the isolated liver perfusion. Hepatic gluconeogenesis in arthritic rats was generally lower than in normal rats. The difference between normal and arthritic rats depended on the gluconeogenic substrate. In the absence of glucagon the following sequence of decreasing differences was found: alanine (-71.8 per cent) reverse similarglutamine (-71.7 per cent)>pyruvate (-60 per cent)>lactate+pyruvate (-44.9 per cent)>xylitol (n.s.=non-significant) reverse similarglycerol (n.s.). For most substrates glucagon increased hepatic gluconeogenesis in both normal and arthritic rats. The difference between normal and arthritic rats, however, tended to diminish, as revealed by the data of the following sequence: alanine (-48.9 per cent) reverse similarpyruvate (-47.6 per cent)>glutamine (-33.8 per cent)>glycerol (n.s.) reverse similarlactate+pyruvate (n.s.) reverse similarxylitol (n.s.). The causes for the reduced hepatic gluconeogenesis in arthritic rats are probably related to: (a) lower activities of key enzymes catalyzing most probably steps preceding phosphoenolpyruvate (e.g. phosphoenolpyruvate carboxykinase, pyruvate carboxylase, etc. ); (b) a reduced availability of reducing equivalents in the cytosol; (c) specific differences in the situations induced by hormones or by the individual substrates. Since glycaemia is almost normal in chronically arthritic rats, it seems that lower gluconeogenesis is actually adapted to the specific needs of these animals.     

Effectiveness of gentamicin sulfate in suppurative-inflammatory processes of varying localization]

Antibiotic sensitivity of 486 strains of grampositive and gramnegative organisms isolated from patients with purulent infections was studied in vitro. Gentamicin was shown to be highly active as compared to kanamycin and other antibiotics against the main causative agents of purulent inflammatory infections including multiresistant E. coli, Proteus, Ps. aeruginosa, Staphylococcus. High efficiency of gentamicin in therapy of peritonitis, septic conditions, purulent postoperative wounds, infections of the urinary tract, pneumonia, etc. (197 patients) was shown. Positive results were obtained in 87.4 per cent of the cases. Side effects, such as albuminuria, hyperthermic reaction, rash, pruritis were registered in 3 per cent of the patients.     

Antibiotic resistance dynamics of plasma-coagulating staphylococci isolated from patients in 1970-1975]

Resistance of 2345 strains of plasmocoagulating staphylococci isolated from purulent inflammatory foci of surgical patients was studied with respect to the widely used antibiotics by the method of standard paper discs in 1970--1975. It was noted that the cultures resistant to erythromycin and monomycin were more frequent, i.e. from 24.2 +/- 2.5 to 51.4 +/- 3.4 per cent and from 1.0 +/- 0.6 to 28.0 +/- 2.1 per cent respectively, p less than 0.001 in both cases, while the percentage of the strains resistant to benzylpenicillin and tetracycline steadily increased, i.e. from 69.9 +/- 2.4 to 47.0 +/- 2.3 per cent and from 72.8 +/- 2.4 to 28.4 +/- 2.1 per cent respectively, p less than 0.001 in both cases. The number of the resistant cultures to streptomycin and levomycetin slightly changed and was relatively high (about 50 per cent and more). Direct correlation (mean and pronounced) between the amount of levomycetin, tetracycline, erythromycin or monomycin used per citizen of Minsk and the frequency of the strains isolated from the patients to these drugs was noted.     

Selective medium with nalidixic acid for isolating antibiotic-producing Actinomyces

The majority of actinomycetes belonging to various genera proved to be resistant to nalidixic acid concentrations having an inhibitory effect on bacteria with trailing growth i.e. B. subtilis and B. mycoides. The bacteria prevented isolation of actinomycetes as pure cultures. The use of a selective medium with nalidixic acid for isolation of soil actinomycetes resulted in 20 per cent increase in the number of the actinomycetes isolated as pure cultures. Preliminary treatment of the soil samples with calcium carbonate under moist conditions followed by the inoculation to the medium with nalidixic acid made it possible to increase isolation of actinomycetes at most 100-fold. With this complex method 495 actinomycete cultures were isolated, their antibiotic properties were studied and their taxonomic position at the genus level was determined. The complex method including the preliminary treatment of soil samples with calcium carbonate followed by inoculation to the selective medium with nalidixic acid is efficient and may be recommended for screening organisms producing new antibiotics.     

Isolation of Legionella from water samples using various culture methods

The efficacy of a non-selective medium and two selective media were compared for the isolation of legionellas from water samples. The effect of acid wash treatment for decontamination of the water samples on the isolation frequency of legionellas was also studied. The 236 samples were taken from cooling, humidifying and drinking water systems; 21% were legionella-positive when inoculated directly on modified Wadowsky-Yee (MWY) medium and 26% were positive when concentrated (x 200) before cultivation on MWY or CCVC media. Inoculation on MWY medium after concentration followed by decontamination by the acid-wash technique gave the highest isolation frequency (31%). The lowest frequency (8%) was found with the non-selective BCYEα medium. An isolation frequency of 28% was achieved with the BCYEα medium after concentration and acid-wash treatment of the samples. Forty per cent of the samples were positive for legionellas when the results from all the culture methods were combined. Not all the legionella-positive samples were identified by a single culture method. Ninety-three of the 95 positive samples were detected with the two best combinations of three culture methods. The best culture method for detecting legionellas depended on the source of the water sample. Some water quality characteristics, like temperature and organic matter content, affected the isolation frequency of Legionella spp.     

The genetics of urinary tract malformations

In this discussion I have excluded consideration of the genetics of purely renal malformations, such as polycystic kidneys, and of functional disorders of the kidney. Systematic family studies are available for renal agenesis, duplication of the ureters, vesico-ureteric reflux (each probably due to maldevelopment of the ureteric bud), bladder exstrophy and hypospadias as isolated malformations. Renal agenesis has a birth frequency of about 1.2 in 10 000 and the proportion affected of sibs is about 3 per cent. Duplication of the ureter has a birth frequency of about 1 per cent and the proportion affected of sibs and parents of probands is about 12 per cent. Vesico-ureteral reflux also has a prevalence in early childhood of about 1 per cent and the proportion of sibs affected is about 10 per cent. Bladder exstrophy has a birth frequency of about 1 in 20 000 and perhaps about 1 per cent of sibs are affected. Hypospadias has a birth frequency in boys of about 1 in 300 and the proportion affected of brothers is about 10 per cent. Further family studies are needed of these malformations when they occur in isolation. Either the multifactorial threshold model or dominant inheritance with reduced penetrance and varied expressivity would fit the data available.     

Isolation of intact mitochondria from the rat liver using vibration

A method for isolating mitochondria from the rat liver is described. In this method the homogenization step is replaced by vibration with the frequency of 50 Hz realized by a simple device. Mitochondria isolated by vibration demonstrate higher indices of the oxidative phosphorylation with succinate and glutamate + malate used as substrates than those isolated by homogenization do. The method described permits decreasing considerably the isolation medium expenditure remaining the mitochondria yield per gram of the liver unchanged.     

Microflora of gastric juice and its sensitivity to antibiotics in post-gastrectomy gastritis

Fifty four patients with postresection gastritis and 13 healthy adults were examined. 141 microbial cultures belonging to 33 species were isolated from the gastric juice of the patients. In the healthy persons 27 cultures belonging to 7 species were isolated from the gastric juice. In the gastric juice of the patients there predominated enteric bacteria and enterococci (64.8 +/- 6.5 and 57.4 +/- 6.7 per cent respectively). Among the enteric bacteria Escherichia coli and Proteus spp. were the most frequent. Contamination of the gastric juice by such microbes amounted to 10(5)-10(9) microbial bodies per 1 ml. The isolates were mainly sensitive to gentamicin (84.8 +/- 2.9 per cent).     

The structure and antibiotic sensitivity of the causative agents of community-acquired infectious diseases of bacterial origin in children]

Four hundred and forty pediatric patients at the age of 7 days to 15 years with various infections admitted to the Hospital within a month were examined. The biological material was inoculated to blood agar on the first days of the patient admittance to the Hospital and after the growth the organisms were isolated and identified. Antibiotic susceptibility of the isolates was assayed with the disk diffusion method. 479 strains in all were tested. The most frequent cases requiring hospitalization and antibiotic therapy were those of respiratory tract infections (54.09 per cent), urinary tract infections (26.36 per cent), cutaneous and subcutaneous fat diseases, gastrointestinal diseases and others (about 25 per cent of the cases in all). The main pathogens were Streptococcus viridans, S.aureus and S.epidermidis, as well as Enterobacteriaceae (chiefly E.coli) whose frequencies were practically equal (in 25-35 per cent of the cases). The Pneumococcus isolates amounted to 6.3 per cent. Nonfermenting bacteria (Pseudomonas aeruginosa and Acinetobacter) and some representatives of Enterobacteriaceae (Citrobacter, Serratia, Morganella) were isolated from 7 per cent of the patients. The frequency of Klebsiella and Enterobacter was about 11 per cent. The main pathogens were tested for their susceptibility to amoxycillin/clavulanic acid, ampicillin, oxacillin and gentamicin. The least active antibiotic was ampicillin. 88.8 per cent of the E.coli isolates and 100 per cent of the Klebsiella, P.mirabilis, Morganella, Citrobacter, Enterobacter and Serratia isolates were resistant to it. 53.2 per cent of the Streptococcus isolates including 64.5 per cent of the Pneumococcus isolates were as well resistant to ampicillin. 59.5 per cent of the Streptococcus isolates (mainly S.viridans and Enterococcus) was susceptible to oxacillin, 22.2 per cent of them being moderately susceptible. 62.5 per cent of the Pneumococcus isolates and 78.1 per cent of the Staphylococcus isolates were also susceptible to oxacillin. The highest susceptibility of the isolates was that to amoxycillin/clavulanic acid, i.e. 90.1 per cent of the strains, 79.9 per cent of them being highly susceptible. All the isolates of Citrobacter, Serratia and Morganella and some isolates of P.aeruginosa, Acinetobacter, Enterobacter, Klebsiella and E.coli were resistant to amoxycillin/clavulanic acid. As for the latter 5 organisms their susceptibility to amoxycillin/clavulanic acid was comparable with that to gentamicin. The susceptibility of the Streptococcus and Staphylococcus isolates to amoxycillin/clavulanic acid was significantly much higher than that to oxacillin, gentamicin and ampicillin: 93 per cent of the Streptococcus isolates (62.7 per cent of the Pneumococcus isolates) and 90.7 per cent of the Staphylococcus isolates.     

Modified method for selective enrichment and isolation of Bacillus thuringiensis from soil

Many colonies of Bacillus thuringiensis (Bt) were found to be lost using the isolation technique described by Martin and Travers modified by Morris (Morris method). Hence, a modified method for isolation of B. thuringiensis is described and compared with the Morris method. Screening methodology adopted by this method delivers an immensely rich and potentially more useful library of Bt colonies with ‘presumptive-positive’ morphology and 10-fold higher per cent frequency of Bt colonies as compared to the Morris method.     

Comparative in vitro activity of cefepime and other antibiotics against clinical strains of gram-negative bacteria]

In vitro activity of cefepime against etiologically significant strains of gramnegative microflora of patients treated in the Reanimation and Intensive Care Unit after cardiosurgical operations was evaluated. Sixty four strains of gramnegative aerobic bacteria isolated within the period from October 2001 to April 2002 were tested. The isolates susceptibility was determined by the disk diffusion method. Cefepime had an obvious advantage over the 3rd generation cephalosporins. Low incidence of cefepime resistant strains of the problem organisms in the Reanimation and Intensive Care Unit should be taken into account in empirical therapy of infections due to such pathogens.