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.     

Comparative Inhibition of Methicillin-resistant Strains of Staphylococcus aureus by Lysostaphin and Otner Antibiotics

Sixteen methicillin-resistant strains of Staphylococcus aureus obtained from Europe were found to be sensitive to the lytic activity of lysotaphin. With only minor exceptions, the strains were found to be sensitive to novobiocin, erythromycin, fusidic acid, and lincomycin, and slightly less sensitive to vancomycin and chloramphenicol. All strains were resistant to tetracycline, penicillinase-sensitive penicillins (benzylpenicillin, ampicillin, and propicillin), penicillinase-resistant penicillins (methicillin, nafcillin, ancillin, oxacillin, cloxacillin, and dicloxacillin), and two cephalosporin antibiotics (cephalothin and cephaloridine).     

E. coli resistance to antibiotics on the material studied and the structure of the antibiotic resistance of the strains]

Standard filter paper discs were used to determine the sensitivity of 943 strains of E. coli isolated in 1970-1974 from patients' purulent-inflammatory foci with respect to benzylpenicillin, streptomycin, levomycetin, tetracycline, erythromycin and monomycin. An increase in the specific weight of the cultures resistant to the 6 drugs from 4.7 +/- 1.7 per cent in 1970 to 16.0 +/- 2.6 per cent in 1974 was observed. Strains resistant to 5--6 antibiotis were more often isolated from the urine (64.6 per cent) and the wound content (48.9 per cent) and rarer from the abdominal cavity exudate (23.1 per cent), bile (28.0 per cent) and sputum (30.1 per cent). Most often certain combinations of resistance to benzylpenicillin, streptomycin, tetracycline and erythromycin were found in the E. coli strains tested.     

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.     

Antimicrobial susceptibility of some streptococci strains of anginosus group isolated from oral and maxillofacial infections

Streptococci strains of the anginosus group isolated from various oral and maxillofacial infections (OMF) were screened for their susceptibility to the following antimicrobial agents: benzylpenicillin, ampicillin, oxacillin, cephalothin, ceftazidime, cefotaxime, cefuroxime, erythromycin, clindamycin, tetracycline, chloramphenicol, vancomycin and trimethoprime-sulphamethoxazole. The isolates were susceptable to: clindamycin, chloramphenicol, vancomycin and all beta-lactam antibiotics, except ceftazidime to which 54.5% of the strains showed intermediate susceptibility. Intermediate susceptibility to tetracycline was found in 11.3% of the strains, whereas resistance to the same antibiotic was demonstrated in 61.4%. Resistance to erythromycin and trimethoprime-sulphamethoxazole was of 2.3% for both. In conclusion, penicillin is the drug of choice in infections caused by streptococci of the anginosus group.     

Production of toxic shock exotoxin by Staphylococcus aureus strains resistant and sensitive to antibiotics

Three hundred and ninety two strains of S. aureus isolated from bacteria carriers and patients with staphylococcal infections in different regions of the Soviet Union were investigated. 55.9 per cent of the isolates were able to produce exotoxin of toxic shock. No regular relation between resistance to definite antibiotics (tetracycline, chloramphenicol, benzylpenicillin, streptomycin, lincomycin, erythromycin, oleandomycin, gentamicin and methicillin) and the polyresistance range on the one hand and the ability to produce toxic shock exotoxin on the other hand was revealed.     

Antibiotic sensitivity of the bacterial microflora from the sputum of children with acute pneumonia]

Bacteriological analysis of sputum of 598 children with acute pneumonia was performed. Sensivity of 1348 cultures belonging to 8 bacterial species with respect to benzylpenicillin, streptomycin, chloramphenicol, tetracycline, oxytetracycline, chlortetracycline, erythromycin, oleandomycin, neomycin and monomycin was determined. It was shown that the sputum microflora was often resistant to the antibiotics widely used in the medical practice for prolonged periods of time, such as benzylpenicillin, streptomycin, chloramphenicol, tetracyclines. However, it usually remained sunsitive to neomycin, monomycin, erythromycin and oleandomycin. It was found that antibioticogrammes defining the antibiotic choice were of great significance for therapy of acute pneumonia.     

Antibiotic sensitivity of the causative agents of suppurative surgical infection]

Sensitivity of 1492 strains of the causative agents of the surgical purulent infections, i. e. pathogenic Staphylococcus, Proteus, Ps. aeruginosa and E. coli to benzylpenicillin, streptomycin, levomycetin, tetracycline, erythromycin, oleandomycin, monomycin, kanamycin, novobiocin, ampicillin, oxacillin, ceporin, gentamicin and rifampicin was studied. Gentamicin was most active against all the bacterial species tested. The staphylococci were in addition sensitive in a high percentage of the cases to rifampicin, novobiocin, ceporin, monomycin and kanamycin. The isolates of E. coli were in addition sensitive to ceporin, monomycin and kanamycin. Sensitivity of the strains of Ps. aeruginosa and Proteus was low to all of the antibiotics except gentamycin. Most of the strains of the causative agents of the surgical purulent infections were multiresistant to 4 antibiotics. The number of the staphylococcal strains sensitive to benzylpenicillin, streptomycin and levomycetin increased in 1976 as compared to 1975 on the background of a limited use of these antibiotics in clinics.     

Interaction of aminoglycosides and the other antibiotic on selected bacterial strains

The aim of this study was to analyse the activity interaction of aminoglycosides (gentamicin, kanamycin, streptomycin and dihydrostreptomycin) when combined with other antibiotics (lincomycin, benzylpenicillin, amoxicillin, cephalexin, spectinomycin and erythromycin), on selected clinical bacterial strains. The checkerboard method has been selected from the traditional assays for the measurement of antibiotic interaction. Checkerboard results for all strains demonstrated synergism for nine cases (9/112--8%). Additive effects were predominant--73/112--65.2%. In 12.5% neutral effects were shown, but in 11.6% of combinations FIC indexes were not possible to calculate, because of the resistance of clinical strains to the highest concentration of at least one antibiotic. The best results were achieved for combinations of dihydrostreptomycin with procaine penicillin because of higher number of cases synergy effect was observed. Antagonism of aminoglycosides and beta-lactams in case of gentamicin and amoxicillin for E. coli and E. cloacea strains were shown. Potential activity for combination of streptomycin and erythromycin was shown.     

Resistance of some strains ofBacteroides to ampicillin,methicillin and cloxacillin

Twenty-three strains of thefragilis-convexus group ofBacteroides and two strains of thethetaiotaomicron group have been tested for sensitivity to ampicillin, methicillin and benzylpenicillin. Thirteen of these strains (twelve of thefragilis-convexus group and one of thethetaiotaomicron group) have been tested to cloxacillin, tetracycline, chloramphenicol and erythromycin.The strains proved to be resistant to benzylpenicillin, ampicillin, methicillin and cloxacillin.     

Frequency of R Factor-mediated Multiple Drug Resistance in Klebsiella and Aerobacter

A comparative study was done on the transfer frequency of R factors from 90 strains of multiple drug-resistant Aerobacter and 81 strains of Klebsiella to Escherichia coli CSH-2 (F(-), met(-), pro(-), Nal-r). The most common resistance patterns for the Aerobacter isolants were ampicillin streptomycin chloramphenicol tetracycline and ampicillin streptomycin chloramphenicol tetracycline kanamycin neomycin; for the Klebsiella isolants, the most common resistance pattern was ampicillin kanamycin streptomycin tetracycline chloramphenicol neomycin. R factors were isolated from 14.1% of the Aerobacter strains; 61.5% of these R factors harbored R determinants for ampicillin streptomycin tetracycline. R factors were isolated from 79.1% of the Klebsiella strains; four R factors were isolated with significant frequency; streptomycin chloramphenicol kanamycin neomycin, 37.5%; ampicillin streptomycin tetracycline kanamycin neomycin, 14.1%; ampicillin streptomycin tetracycline, 12.5%; and streptomycin chloramphenicol tetracycline, 12.5%.Chloramphenicol, kanamycin, and neomycin resistance was rarely transferred from the Aerobacter strains, although over 50% of the clinical isolants possessed resistance to these antibiotics. In contrast, over 75% of the Klebsiella strains transferred resistance to chloramphenicol, kanamycin, neomycin. Highest frequency of transferred resistance to individual drugs in the Aerobacter strains was to streptomycin (14.8%), whereas in the Klebsiella group resistance to four drugs was transferred at a very high frequency: streptomycin (80.8%), chloramphenicol (78.5%), kanamycin (76.4%), and neomycin (75.9%).     

Changes in antibiotic sensitivity in strains of Staphylococcus aureus, 1952-78.

Two hundred strains of Staphylococcus aureus isolated from outpatients with infections of the skin and subcutaneous tissues were tested for sensitivity to penicillin, erythromycin, tetracycline, sodium fusidate, methicillin, clindamycin, chloramphenicol, and gentamicin. One hundred and sixty-three (81.5%) of the strains were resistant to penicillin and 16 (8%) resistant to tetracycline. Incidence of resistance to other antibiotics was low. No strain was resistant to chloramphenicol, gentamicin, or methicillin. When compared with results of earlier studies, there was an increase in the incidence of resistance to penicillin and tetracycline, but no appreciable increase in resistance to other antibiotics.     

Antibiotic sensitivity pattern; experience at University Hospital, Riyadh, Saudi Arabia

Results of sensitivity testing were discussed based on examination of 5192 isolates of the various bacteria isolated from clinical specimens from King Khalid University Hospital in Riyadh, Saudi Arabia. Streptococcus pyogenes and Streptococcus pneumoniae were sensitive to penicillin and erythromycin. The sensitivity pattern of Staphylococcus aureus was also predictable as they were fairly sensitive to both methicillin (98%) and erythromycin (96%). Neisseria gonorrhoeae (27%) showed a high level of resistance to penicillin. The resistance of Haemophilus influenzae to ampicillin and chloramphenicol was low. Brucella species was sensitive to tetracycline and rifampicin; resistance to streptomycin and cotrimoxazole was minimal being 1% and 6% respectively. The resistance of E. coli, Klebsiella species and Proteus species to second and third generation cephalosporins and amikacin was fairly low ranging from 1.3% to 3%. The gentamicin resistance for these organisms was also within the acceptable range (3%-10%). Gentamicin and amikacin resistance for Pseudomonas aeruginosa was low (2-8%). Salmonella typhi was sensitive to ampicillin, cotrimoxazole, and chloramphenicol. Salmonella enteritidis, Shigella species, and enteropathogenic E. coli were highly resistant to various antibiotics. Campylobacter jejuni was sensitive to gentamicin but 6% of isolates were resistant to erythromycin. Ninety six percent of Gram-negative rods except P. aeruginosa isolated from urine of patients having urinary tract infections were sensitive to amoxycillin-clavulanic acid. In addition, P. aeruginosa showed fairly low resistance to norfloxacin which is given orally to treat cystitis caused by this organism.     

Sensitivity of Proteus hauseri bacteria to chemotherapeutic preparations depending on the cultivation conditions and on the composition of the nutrient medium]

Sensitivity of 227 Proteus strains isolated from patients was studied comparatively using the agar-diffusion method (disks) and the method of serial dilutions. Marked differences in the numbers of the strains resistant to benzylpenicillin and chloramphenicol were found with the above methods. It was shown that the ingredients of Ploskirev's medium significantly (by 2.8--13.5 times) inhibited the antibacterial activity of streptomycin, neomycin, monomycin, kanamycin, ampicillin and nalidixic acid and had practically no effect on the activity of benzylpenicillin, chloramphenicol and furazolidone. The values of the MIC of the drugs used in the experiment with liquid media correlated with those obtained with Sabouro's medium, which provided recommendation of the latter for determination of Proteus sensitivity by the method of serial dilutions in the solid medium, Cultivation of Proteus at a temperature of 40 degrees C resulted in a decrease of the resistance to most of the drugs tested by (by 3--12.4 times).     

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.     

Antibiotic sensitivity of Staphylococci populating the breast skin of nursing women

Sensitivity to penicillins, tetracycline, erythromycin and lincomycin was tested in 1513 staphylococcal strains isolated from the skin of various anatomic areas of the breast of nursing mothers. It was shown that 82.9, 78.4 and 33.9 per cent of the isolated cultures were highly sensitive to lincomycin, erythromycin and methicillin respectively. Sensitivity to tetracycline and benzylpenicillin was detected in 33.1 and 19.8 per cent of the cultures respectively. The study of the resistance spectra of 1343 strains resistant to certain antibiotics revealed that 498 cultures (37.1 per cent) were polyresistant. None of the tested antibiotics could be used for selective decontamination of the breast skin with respect to S. aureus in prophylaxis of lactic mastitis.     

Biological properties of sherry yeasts in the presence of antimicrobial preparations

The wine yeasts Cheres were not sensitive to high concentration (500 gamma/ml) of benzylpenicillin, streptomycin, tetracycline, oxytetracycline, chlortetracycline, morphocycline, erythromycin, oleandomycin, monomycin, neomycin, kanamycin, polymyxin, ampicillin, oxacillin, methicillin, ceporin, ristomycin, levomycetin, furadonin and furazolidone. In concentrations of 50 to 500 gamma-ml oleadomycin, chlortetracycline, oxytetracycline, kanamycin and ristomycin inhibited synthesis of the Cheres yeast biomass. Benzylpenicillin, polymyxin, neomycin and ampicillin in concentrations of 50 to 100 gamma/ml had a stimulating effect on the yeast biomass synthesis.     

Sensitivity to antibacterial preparations of the pathogenic staphylococci isolated from carriers]

After discontinuation of the use of antibiotics for sanation of the carriers of pathogenic staphylococci among the staff of a maternity unit, the number of the strains resistant to penicillin, streptomycin, chlortetracycline, tetracycline, levomycetin, erythromycin, monomycin and neomycin decreased 1.3, 2.9, 10,4.3,5.5,1.5,3.9 and 2.4 times respectively. The differences were statistically reliable. The causes of the antibiotic resistance decrease require further investigation.     

Antimicrobial susceptibilities of Campylobacter sp strains isolated from humans in 2005 to 2006 in Bielsko-Biala Region, Poland

Campylobacter jejuni and Campylobacter coli are frequent causes of bacterial gastroeneritis in humans worldwide. Campylobacteriois is usually a self-limiting disease and therapy with antibiotics is required in severe clinical infections. The objective [corrected] of this study was to determine the antibiotic resistance of C. jejuni and C. coli isolated from humans with diarrhea during 2005-2006 in Bielsko-Biala region in Poland. The MICs of ciprofloxacin, tetracycline, erythromycin, gentamicin and ampicillin were determined by the E-test method. It was observed that 23 % and 6% C. jejuni isolates were resistant to two and three antibiotics, respectively. All isolates of Campylobacter sp. were sensitive to erythromycin and gentamicin. From the 69 C. jejuni strains 58% were resistant to ciprofloxacin, 23% to tetracycline and 17% to ampicillin. From the 8 C. coli strains all were resistant to ciprofloxacin, 62,5% to ampicillin and 12,5% to tetracycline.     

Plasmid profiling and curing of Lactobacillus strains isolated from the gastrointestinal tract of chicken

In this study, we assessed the susceptibility of 12 Lactobacillus strains, all of which had been isolated from the gastrointestinal tracts of chicken, to three antibiotics (chloramphenicol, erythromycin and tetracycline) used commonly as selective markers in transformation studies of lactic acid bacteria. Among these strains, 17%, 58%, and 25% were found to exhibit a high degree of resistance to 200 microg/ml of tetracycline, erythromycin, and chloramphenicol, respectively. Seven of the 12 Lactobacillus strains exhibiting resistance to at least 50 microg/ml of chloramphenicol or erythromycin, and five strains exhibiting resistance to at least 50 microg/ml of tetracycline, were subsequently subjected to plasmid curing with chemical curing agents, such as novobiocin, acriflavin, SDS, and ethidium bromide. In no cases did the antibiotic resistance of these strains prove to be curable, with the exception of the erythromycin resistance exhibited by five Lactobacillus strains (L. acidophilus I16 and I26, L. fermentum I24 and C17, and L. brevis C10). Analysis of the plasmid profiles of these five cured derivatives revealed that all of the derivatives, except for L. acidophilus I16, possessed profiles similar to those of wild-type strains. The curing of L. acidophilus I16 was accompanied by the loss of 4.4 kb, 6.1 kb, and 11.5 kb plasmids.