Microflora of suppurative inflammatory foci in surgical patients and its sensitivity to antibiotics

Materials from 1134 patients with various surgical infections were tested. From the materials collected from purulent inflammatory foci 2137 cultures were isolated. Many of them belonged to Micrococcaceae (63.7 per cent). Cultures belonging to Enterobacteriaceae and Streptococcaceae were isolated from 50.9 and 25.2 per cent of the patients respectively. Isolates belonging to other families were less frequent: diphtheroids were isolated from 13.3 per cent of the patients and Pseudomonas spp. were isolated from 10.6 per cent of the patients. The majority of the isolates of diverse taxons were sensitive to gentamicin (73 to 98.4 per cent). As the second active antibiotic the following should be indicated: fusidin, active against staphylococci (S. epidermidis and S. aureus, 70.5 and 83.3 per cent respectively); ristomycin, active against micrococci and diphtheroids (75.3 and 79.1 per cent respectively); ampicillin, active against S. faecalis (61.3 per cent); polymyxin, active against the trib microbes Escherichia, Klebsiella and Pseudomonas (75.5, 64.3 and 71.4 per cent respectively). No second antibiotic active against a significant percentage of various species of Proteus, fecal alkali forming bacteria, and A. calcoaceticus was stated. Sporulating aerobes were sensitive to the majority of the antibiotics.     

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.     

Response to antibiotics of Proteus strains isolated from different types of clinical material

The data on the study of the antibiotic response to 42 Proteus strains isolated from different sources in the hospitals of Kharkov are presented. The isolates belonged to P. mirabilis and P. vulgaris. Many strains were resistant to gentamicin, ampicillin and carbenicillin irrespective of the isolation source. 58.0 and 90.3 per cent of the strains isolated from patients with intestinal infections, 66.6 and 100 per cent of the strains isolated from patients with otitis, 33.3 and 66.6 per cent of the strains isolated from patients with bronchopulmonary affections and 100 and 100 per cent of the strains isolated from patients with urological diseases were resistant to gentamicin and carbenicillin, respectively. As for ampicillin, the respective figures were 74.2, 66.6, 66.6 and 100 per cent. All the strains of P. vulgaris isolated from patients with otitis, urological diseases and bronchopulmonary affections were resistant to ampicillin. The MIC of carbenicillin for all the strains except 4 indole-positive strains of P. vulgaris isolated from the faeces and bronchial excreta was much higher than the borderline values.     

Oral bacteria resistant to mercury and to antibiotics are present in children with no previous exposure to amalgam restorative materials

Dental plaque from 76 children without amalgam restorations was screened for bacteria resistant to mercuric chloride. Seventy-one per cent of the children harboured mercury-resistant oral bacteria and the median percentage of the total oral microflora resistant to mercuric chloride was 0.007% (range 0-5.3%). Eighty-seven mercury-resistant bacteria were isolated and 86% of these were streptococci with Streptococcus mitis predominating. Sixty per cent of the mercury-resistant isolates were also resistant to at least one of the four antibiotics tested (penicillin, ampicillin, erythromycin and tetracycline) with resistance to tetracycline (40% of isolates) most frequently encountered.     

The comparative activity of cefepime and other current antibiotics against microorganisms isolated from patients in pediatric intensive therapy units]

Comparative activity of cefepime, ceftazidime, ceftriaxone, ciprofloxacin, imipenem and piperacillin/tazobactam against isolates from patients of pediatric intensive care units within October-December 1998 was studied. The isolates were identified with the Walkaway-40 System. The antibiotic susceptibility was evaluated by the E-test on the Mueller-Hinton II agar. The data were interpreted in accordance with the NCCLS. The number of the isolates totaled 100. Among them not more than 10 to 12 strains belonged to the same species. 92 per cent of the isolates was susceptible to cefepime and 70 to 75 per cent of the isolates were susceptible to the third generation cephalosporins. Piperacillin/tazobactam proved to be highly susceptible, the number of the isolates resistant and moderately resistant to it being 6 and 1 per cent respectively. The results showed that cefepime was intermediate between the third generation cephalosporins and carbapenems.     

Antibiotic sensitivity and the characteristics of transmissive R plasmids in Shigella belonging to various species]

Sensitivity of 241 Shigella strains isolated from patients at various regions of the USSR in 1975--1978 was tested with respect to 14 antibiotics by the method of serial dilutions. 90.5 per cent of the isolates proved to be resistant to the antibacterial drugs and the greater part of 75.9 per cent of them had multiple resistance. The resistance of the Shigella was most pronounced and frequent with respect to tetracycline, streptomycin, levomycetin, as well as ampicillin and carbenicillin. Gentamicin, cephaloridin, polymyxin M, kanamycin, monomycin, neomycin and rifampicin were highly active against the Shigella. More than 50 per cent of the isolates were sensitive to levomycetin, ampicillin and carbenicillin. Differences in the frequency of the resistant strains and the spectrum of the antibiotic resistance of different Shigella subgroups (species) were observed. The study of 173 multiple resistant Shigella strains showed that about 67 per cent of the strains had a capacity for transduction of the resistance markers into the recipient cells of E. coli. The conjugative R-plasmids were most frequent in Sh. boydii and Sh. sonnei (95 and 95 per cent respectively), less frequent in Sh. flexneri and Sh. newcastle (68 and 53 per cent respectively) and least frequent in the mannitol negative Shigella (25 per cent). The capacity for transduction of R-plasmids in the strains carrying the determinants of resistance to 2 or 3 antibiotics was higher than in the strains carrying the determinant of resistance to one antibiotic. The clinical Shigella strains tested mainly had transmissive R-plasmids of fi--character (79 per cent).     

Antibiotic sensitivity of nonfermenting gram-negative bacteria

Antibiotic resistance of 132 strains of nonfermenting gram-negative bacteria (NGNB) was studied. 43, 20, 17, 14 and 12 of them belonged to Acinetobacter calcoaceticus (anitratus and lwoffi), Pseudomonas cepacia, Alcaligenes faecalis, P. stutzeri and P. maltophilia, respectively. With rare exceptions all the strains were resistant to benzylpenicillin, oxacillin, lincomycin, ampicillin and cephaloridine. Sensitivity to the other antibiotics varied within wide ranges. Amikacin (94.3 per cent) and tobramycin (90.8 per cent), as well as polymyxin, rifampicin and gentamicin (71.7-66.9 per cent) had the highest effect. The majority of the antibiotics had higher activity (p less than 0.01) against the tested NGNB as compared to their activity against P. aeruginosa. Antibioticograms of every of the tested species of NGNB revealed that P. cepacia and P. stutzeri were the most resistant species. The biovars of Acinetobacter varied in their antibiotic resistance: A. subsp. lwoffi was more sensitive to the majority of the antibiotics though some of them, i.e. doxycycline, carbenicillin, and polymyxin were more active against A. subsp. anitratus.     

Sensitivity of Shigella to antibiotics]

Three hundred and twenty two Shigella cultures isolated from dysentery patients within 1986-1989 were tested with the use of standard paper disks for their sensitivity to levomycetin, streptomycin, tetracycline, monomycin, neomycin, kanamycin, erythromycin, gentamicin, carbenicillin, ampicillin, oxacillin, methicillin and doxycycline. The number of the cultures belonging to Shigella sonnei amounted to 85.1 per cent of the total number of the strains studied. 91.9, 89.5, 87.3, 87.3, 80.1 and 80.1 per cent of the cultures were sensitive to gentamicin, kanamycin, carbenicillin, neomycin, levomycetin and ampicillin, respectively. 99.4 per cent of the isolates were resistant to streptomycin and 97.2 per cent were resistant to tetracycline. The sensitivity to erythromycin remained rather high (70.2 per cent). The overwhelming majority of the Shigella sonnei isolates had multiple resistance.     

Antibiotic resistance and its transmissibility in strains of opportunistic enterobacteria

Sensitivity of 39 opportunistic Enterobacteria strains was studied with respect to tetracycline, kanamycin, ampicillin, levomycetin, streptomycin and nevigramon. The strains were isolated from children with acute intestinal infections of obscure etiology. 38 isolates were resistant to one or more drugs. The highest number of the strains was resistant to kanamycin, ampicillin and levomycetin, i.e. 81.5, 84.2 and 84.2 per cent of the cultures respectively. Nevigramon proved to be the most effective in vitro (76.4 per cent of the sensitive strains). The ability of the strains to transfer the antibiotic resistance markers on conjugation was tested. Transmission of R plasmids was shown in 75 per cent of the isolates.     

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).     

Taenia taeniaeformis: Increased cell growth and neutral mucus production in the gastric mucosa of the rat with a larval infection

Gross hyperplasia of the gastric mucosa and excessive mucus production in the stomach occur in rats heavily parasitized with larvae of Taenia taeniaeformis. In this study, a positive correlation between the number of larvae recovered from hepatic cysts and the weight of the stomachs of infected rats was found. By light microscopy, the hyperplasia was restricted to the glandular mucosa. Parietal and chief cells were very rare, and densely PAS-positive mucous cells were the major cell types in the hyperplastic stomach while, in comparison, alcian blue-positive cells were much fewer in number. The isolated gastric mucosa in organ culture had an increased [³H]thymidine incorporation rate in rats infected with T. taeniaeformis. The hexosamine concentration per milligram protein in the hyperplastic stomach mucosa was twice that in the control rat stomach mucosa. By electron microscopy, the apical cytoplasm of the mucous cells was found to be filled with small dark granules. These results indicate that the gastric hyperplasia is caused by stimulation of growth and major differentiation of stem cells to neutral mucus-producing cells.     

Level and nature of the drug resistance of Shigella flexneri]

Characteristics of antibiotic resistance of 300 strains of Shigella flexner 2a isolated from patients within 1976--1977 in the regions where these bacteria were very rare for a long period of time were studied. It was shown that most of the isolates were resistant to chloramphenicol (88.1 per cent), tetracycline (94.8 per cent), streptomycin (89.1 per cent), polymyxin M (82.4 per cent) and others. 46.5--61.6 per cent of the isolates were resistant to neomycin antibiotics. A high level of the resistance was also noted: the bactericidal effect was registered in 52.0-74.0 per cent of the cultures at a dose of 500--1000 microgram/ml. 91.4 per cent of the strains possessed multiple dug resistance, 78.8 per cent of them being simultaneously resistant to 4--7 drugs. Transmissive R-plasmids were found in 68.8 per cent of the isolates. After exposure to acridine dyes the plasmid nature of the resistance was confirmed in 72.3 per cent of the cultures. Variability of the r-determinant sets in r-plasmids was noted. Strains (64.9 per cent) carrying r-determinants Tc, Cm, Sm and Tc, Cm were more frequent. Strains with one transmissive r-determinant were usually solitary.     

Sensitivity to levofloxacin of Mycobacterium tuberculosis strains with various phenotype isolated from patients with newly diagnosed and chronic tuberculosis]

Susceptibility to levofloxacin of 56 strains of Mycobacterium tuberculosis, isolated from 22 patients with first estimated and 84 patients with chronic tuberculosis was investigated. Ratio of multi-drug resistance achieved 54.5 per cent in first group and 94.1 per cent in the second group. 23 (41.1 per cent) isolated strains belonged to individual genotypes, 33 (58.9 per cent)--to Beijing group. All mycobacteria isolates were sensitive to critical concentration of levofloxacin--10 mcg/mL. The results of the investigation proves the ability to recommend levofloxacin application at the patients with first estimated tuberculosis and at the patients with most hazardous tuberculosis pathogen of Beijing group.     

Sensitivity of Corynebacterium diphtheriae isolated in Saint-Petersburg to antibacterial drugs]

One hundred and thirty strains of Corynebacterium diphtheriae isolated in St. Petersburg (42 toxigenic and 88 nontoxigenic) were tested with the method of serial dilutions in solid media for their susceptibility to 20 antibacterial drugs. The MICs of the drugs for the isolates ranged from < or = 0.015 to > or = 32.0 micrograms/ml. 13 per cent of the isolates was resistant at least to one antibacterial drug. The isolates resistant to erythromycin (11.5 per cent), lincomycin (11.5 per cent) and trimethoprim (8.5 per cent) were most frequent. 3 isolates (2.3 per cent) had multiple resistance to 8 drugs: benzylpenicillin, ampicillin, oxacillin, chloramphenicol, erythromycin, lincomycin, trimethoprim, and nitroxolin. No significant differences in the susceptibility of the toxigenic and nontoxigenic strains of C. diphtheriae were detected. Gentamicin, rifampicin, tetracycline, doxycycline and pefloxacin were the most active antibiotics.     

Drug resistance of opportunistic enterobacteria isolated from various sources]

Resistance of 159 strains of opportunistic enterobacteria to 9 antibacterial drugs was studied. The strains were isolated from man and cattle. It was shown that the overwhelming majority of the isolates (93 per cent) were polyresistant irrespective of the genus. There was a high frequency of the strains resistant to the widely used antibiotics such as chloramphenicol (73 per cent), ampicillin (73.6 per cent) and rifampicin (95.6 per cent) and sulfanilamides (99.3 per cent). Gentamicin and nalidixic acid proved to be the most active against the cultures: 11.9 and 10 per cent of the resistant strains, respectively. The strains of enterobacteria isolated from different sources had a sensitivity to the antibiotics. Multiple antibiotic resistance to at least 5 drugs, variability of the spectra and high resistance were more characteristic of the isolates from the animals. The necessity of a rational use of antibacterial drugs in veterinary is indicated.     

Somatostatin cells in the gastric mucosa of small ruminants. Immunohistochemical study

The distribution of somatostatin cells was investigated immunohistochemically in the epithelium of the abomasal mucous membrane of sheep and goats. Tissue samples were taken from different areas at the lesser and greater curvature of the glandular stomach. More somatostatin cells per 0.5 mm2 were found in sheep than in goats, predominantly in the pyloric gland region. In the pyloric area of both species the mucosa in the greater curvature contained more immunoreactive cells than the one in the lesser curvature. A few somatostatin cells with basal cytoplasmic processes of the 'open type' were observed over the entire abomasal mucosa.     

Molecular determination of oxytetracycline-resistant bacteria and their resistance genes from mariculture environments of China

AIMS: To assess the diversity of antibiotic-resistant bacteria and their resistance genes in typical maricultural environments. METHODS AND RESULTS: Multidrug-resistant bacteria and resistance genes from a mariculture farm of China were analysed via cultivation and polymerase chain reaction (PCR) methods. Oxytetracycline (OTC)-resistant bacteria were abundant in both abalone and turbot rearing waters, accounting for 3.7% and 9.9% of the culturable microbes. Multidrug resistance was common, with simultaneous resistance to OTC, chloramphenicol and ampicillin the most common resistance phenotype. 16S rDNA sequence analyses indicate that the typical resistant isolates belonged to marine Vibrio, Pseudoalteromonas or Alteromonas species, with resistance most common in Vibrio splendidus isolates. For OTC resistance, tet(A), tet(B) and tet(M) genes were detected in some multidrug-resistant isolates, with tet(D) being the most common molecular determinant. For chloramphenicol resistance, cat II was common, and floR was also detected, especially in marine Pseudoalteromonas strains. CONCLUSIONS: There is the risk of multidrug-resistant bacteria contamination in mariculture environments and marine Vibrio and Pseudoalteromonas species serve as reservoirs of specific antibiotic resistance determinants. SIGNIFICANCE AND IMPACT OF THE STUDY: This paper and similar findings from Korea and Japan indicate the potential for widespread distribution of antibiotic resistance genes in mariculture environments from the East Asian region of the world.     

Drug resistance of the causative agent of Grigo'rev-Shiga dysentery (Shigella dysenteriae 1)isolated in the USSR

Forty strains of S. dysenteriae 1 isolated in the USSR within 1986-1988 were tested for their resistance to 11 antibacterial drugs. It was shown that 92.5-97.5 per cent of the isolates were resistant to chloramphenicol (Cm) and tetracycline (Tc), 22.5 per cent to streptomycin (Sm), 17.5 per cent to nalidixic acid (Nal) and 10 per cent to ampicillin (Ap) and polymyxin (Pm). Resistance to Cm Tc (51.4 per cent) and Cm Tc Nal (13.5 per cent) represented the predominating phenotype. 35 per cent of the strains carried conjugative R plasmids. In the majority of the cases, the determinants of resistance to Cm and Tc were transferred, which must define the high frequency of the strains resistant to Cm and Tc. All the tested strains were sensitive to gentamicin, neomycin, rifampicin, cefamezin and ciprofloxacin. Since the strains of S. dysenteriae 1 proved to be highly sensitive to the tested drugs it appeared possible to consider them as the drugs of choice in etiotropic therapy of patients with dysentery caused by the pathogens of the Grigoryev-Shiga group.     

Sensitivity of clinical Proteus strains to antibiotics and their combinations]

In 1976 isolation of Proteus from wounds of patients with various purulent processes amounted to 14.5 per cent. Serotypes 0-10, 0-3 and H-3 predominated among the isolates. Sensitivity of 35 clinical strains of Proteus to 10 antibiotics, furagin and nevigramone was studied by the method of serial dilutions in liquid media. All the isolates were highly resistant to the antibiotics except gentamicin, furagin and nevigramone, the MIC of which for most of the strains was 3.12, 1.6-3.12 and 6.25-12.5 gamma/ml, respectively. The effect of 14 combinations of chemotherapeutics was also studied. The combinations of gentamicin with carbenicillin, gentamicin with ampicillin and monomycin with ampicillin proved to be most effective against the Proteus strains tested. The following combinations may be of practical value: monomycin + carbenicillin, kanamycin + ampicillin, kanamycin + carbenicillin, ampicillin + furagin, gentamicin + nevigramone. The combinations of carbenicillin with furagin and gentamicin with furagin were also rational.