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 of Shigella in different regions of the USSR]

Shigella were most sensitive to polymyxin ceporin, ampicillin, neomycin and furazolidone and resistant to chloramphenicol, tetracycline and streptomycin. Shigella resistant simultaneously to two or three drugs mainly to tetracycline + chloramphenicol, tetracycline + streptomycin and tetracycline + chloramphenicol + streptomycin were most frequent. The frequency of the Shigella strains carrying R-plasmids increased from 28 per cent in 1969--1970 to 72.6 per cent in 1977. The Shigella strains isolated during the dysentery outbreak in 1973--1977 carried the R-factor controlling resistance to tetracycline + chloramphenicol, tetracycline + chloramphenicol + streptomycin, tetracycline + chloramphenicol + streptomycin + neomycin. Interaction between separate biochemical types, colicinogenicity and drug resistance classes was found in the Shigella isolates. The data on the effect of antibiotic (tetracyclines) intensive use in stock-raising defining wide spread of the R-plasmids controlling resistance to these drugs were obtained.     

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.     

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.     

Resistance of Shigella to antibiotics

Antibiotic sensitivity of 104 Shigella clinical strains and 104 Escherichia coli strains isolated from patients with acute dysentery not treated with antibiotics in 1986-1987 was studied. It was shown that 100 per cent of the dysentery pathogens and colon bacilli were antibiotic resistant. Strains resistant simultaneously to chloramphenicol, ampicillin, streptomycin, tetracycline, monomycin and kanamycin were the most frequent among the dysentery pathogens. Colon bacilli and dysentery pathogens isolated from the same patient had specific sets of antibiotic resistance markers. Pathogenetic therapy of dysentery and exclusion of antibiotic use for several years did not result in lower numbers of Shigella antibiotic resistant strains.     

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.     

The sensitivity to 12 antibiotics of 125 strains of Streptococcus group B isolated in a maternity home

Sensitivity of 125 strains of group B streptococci isolated from newborns, their mothers and personnel in a maternity home was studied with respect to 12 antibiotics: benzylpenicillin, ampicillin, methicillin, cephalotin, erythromycin, lincomycin, levomycetin (chloramphenicol), oxacillin, tetracycline, streptomycin, gentamicin and ristomycin. The method of serial dilutions in a solid medium was applied. All the strains were sensitive to ristomycin and erythromycin. The predominating number of the strains were sensitive to lincomycin, levomycetin and the beta-lactam antibiotics. Strains resistant or moderately resistant to benzylpenicillin, ampicillin, oxacillin, methicillin and cephalotin were detected. The majority of the strains were resistant to streptomycin, tetracycline and gentamicin. Multiple antibiotic resistance with 2-7 determinants was revealed in 11.2 per cent of the strains. The antibiotic sensitivity of the strains isolated from the newborns, their mothers and the personnel in the maternity home was on the whole similar or insignificantly differed.     

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.     

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.     

Increase in drug resistance among Shigella dysenteriae,Sh flexneri,and Sh boydii.

Two thousand three hundred and seventy strains of Shigella dysenteriae, Sh flexneri, and Sh boydii isolated in England and Wales from 1974 to 1978 were tested for resistance to 12 antimicrobial drugs. Eighty per cent of strains were resistant to one or more drugs, with sulphonamide resistance occurring most frequently. Resistance to streptomycin, tetracycline, ampicillin, and chloramphenicol increased during the period, as did the incidence of multiple resistance. Most infections due to Sh dysenteriae, Sh flexneri, and Sh boydii are acquired abroad, and the increasing incidence of drug resistance among these organisms contrasts with the decreasing incidence of resistance among the indigenous Sh sonnei. These findings may indicate the need for better control of antibiotic use, particularly in developing countries.     

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.     

Plasmid-mediated drug resistance of shigellae in Kuwait

Of 153 clinical isolates of shigellae examined, 64.7% belonged toShigella flexneri, 18.9% toSh. sonnei, 11.8% toSh. boydii and 4.6% toSh. dysenteriae. Part of these isolates were resistant to sulfamethoxazole and streptomycin (88.2% each), ampicillin (66.70, tetracycline (63.40 and co-trimoxazole (43.10, with levels of resistance (MIC₅₀ and MIC₉₀) being invariably high. Resistance to three or more drugs (multidrug resistance) was seen in 77.8% of the isolates. All the 25 strains examined for transfer of resistance contained R-plasmids, both autotransferable and non-autotransferable (mobilized by transfer factor X). The frequency of transfer of different r-determinants varied from 2.7 · 10^–8 to 1.4 · 10.     

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.     

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.     

Antibiotic resistance of Pseudomonas aeruginosa strains isolated from patients with infected burns

Sensitivity to 15 drugs of 248 P. aeruginosa strains isolated from patients with infected burns was studied by the method of agar dilution. All of the strains were resistant to polymyxin M, ceporin, erythromycin and oleandomycin. Most of the strains were resistant to streptomycin, monomycin, ampicillin and rifadin. Moderate resistance of the strains to carbenicillin, morphocycline, vibramycin, kanamycin, tetraolean and tetracycline was observed: the maximum concentrations of these antibiotics (128 microgram/ml) inhibited the growth of 85, 69, 63, 51.8, 43.6 and 41.2 per cent of the strains respectively. Gentamicin proved to be most active against the strains of P. aeruginosa and inhibited 87 per cent of the strains when used in the therapeutic doses. The study provided recomendation of the drugs for parenteral and local use in treatment of burns infected with P. aeruginosa.     

Study of the antibiotic sensitivity of the Shigellae, pathogenic Escherichia, Proteus and Staphylococcus isolated from young children in Tbilisi with acute intestinal diseases]

Sensitivity of Shigella, pathogenic Escherichia, Proteus and Staphylococcus isolated from children with acute intestinal diseases was studied with respect to antibiotics widely used in medical practice: streptomycin, levomycetin, tetracycline, chlortetracycline, oxytetracycline and neomycin. The antibiotic sensitivity was determined with the method of indicator discs. It was found that sensitivity of shigella was: 44 percent to streptomycin, 69.5 per cent to levomycetin, 18.5 per cent to tetracycline, 18.5 per cent to chlortetracycline, 23 per cent to oxytetracycline and 94 per cent to neomycin. Sensitivity of pathogenic Eschericia was 28, 33, 14, 14, 25 and 74 per cent, sensitivity of staphylococci was 46, 56.5, 21, 21, 31.5 and 89.5 per cent, sensitivity of Proteus was 15, 31.5, 3.5, 3.5, 7.5 and 52.5 per cent respectively. Cross resistance with respect to tetracyclines was found in all the microbes studie. Intragenera differences in the antibiotic sensitivity were observed among Shigella and pathogenic Escherichia.     

Dynamics of drug resistance of Vibrio cholerae isolated from surface water reservoirs in Siberia and the Soviet Far East in 1976-1990]

In the study on antibiotic resistance 1383 strains of El Tor Vibrio cholerae isolated from surface water reservoirs in 12 administrative territories of the Siberia and Far East within a period of 15 years were tested. The following antibiotics were used: ampicillin, streptomycin, monomycin, polymyxin, tetracycline, chloramphenicol, rifampicin and nalidixic acid. The resistance was unstable and its pattern was wave-like according to annual changes in the biological cycle. It was especially evident in regard to ampicillin, streptomycin, monomycin and polymyxin. The highest numbers of the strains were resistant to polymyxin, ampicillin and streptomycin (up to 100 per cent in some years). The lowest numbers of the strains were resistant to chloramphenicol (0.4 per cent) and tetracycline (1.9 per cent). No strains resistant to rifampicin and nalidixic acid were isolated. In some cases the antibiotic resistance level depended on the geographical zone where the strain was isolated. A direct quantitative dependence of the resistance level on the MIC was observed: the lower the MIC of the drug was, the lower the number of the strains resistant to it was. Within the 15-year period there was no general tendency to increase the resistance in V. cholerae to the antibiotics used.     

Comparative study of the antibiotic sensitivity of Proteus hauseri bacteria belonging to different serological groups]

Sensitivity to 9 antibiotics of 1040 strains of Proteus belonging to the serological groups 03, 05, 06, 07, 010, 011, 013, 023, 024, 026, 027, 028 and 030 was studied. It was found that the above strains were sensitive and highly sensitive to the aminoglycosides and streptomycin, slightly sensitive to levomycetin and resistant to tetracyclines, erythromycin and penicillin. All the strains were polyresistant and 99.6 per cent of them were resistant to 4--9 antibiotics. Ten types of resistance were found. Proteus strains with the resistance type PETOtCht were most common. No relation between the occurrence of the strains of various serological groups and the character and level of their resistance to the antibiotics was found.     

R—Factors of Escherichia coli from Dressed Beef and Humans

One hundred eighty Escherichia coli strains isolated from raw and cooked dressed beef and from healthy humans were screened for resistance to each of nine antibiotics: chlortetracycline, ampicillin, chloramphenicol, kanamycin, neomycin, nalidixic acid, dihydrostreptomycin, oxytetracycline, and tetracycline. Nearly 80% of the 98 beef isolates and 54% of the 82 human isolates were resistant to one or more of the antibiotics tested. Ampicillin resistance was most frequent among beef isolates, and dihydrostreptomycin resistance was most frequent among isolates of human origin. About 74% of the multiply resistant beef strains and 85% of the multiply resistant human strains transferred all or part of their resistance to E. coli K-12 recipients.     

Serotypes and biotypes and antibiotic susceptibility of Haemophilus influenzae encountered in a clinical laboratory in Taiwan.

Forty-four serologically and biochemically typable Haemophilus influenzae isolates from clinical specimens in Taiwan were subjected to analysis in their relationship with source of isolation and age distribution. It was found that all isolates from blood and cerebrospinal fluid were serotype b, biotype I, and all were in children less than 4 years of age. Serotypes b and e, biotypes I and III were encountered to have the highest incidence of infection caused by H. influenzae in this area. All H. influenzae isolates were further tested for susceptibility to several selected antibiotics. All strains of this organism were susceptible to erythromycin and chloramphenicol. All but two strains were susceptible to tetracycline, whereas more strains were resistant to carbenicillin, gentamycin, keflin, and penicillin. Thirty-four percent strains were found to be resistant to ampicillin and all were beta-lactamase producer. No direct correlation between ampicillin resistance and serotypes or biotypes was recognized.