Transferable Drug Resistance Research Articles

Pharmacokinetics of cefoperazone in the cow by the intramammary route and its effect on mastitis pathogens in vitro.

The pharmacokinetic and microbiological properties of a new third generation cephalosporin, cefoperazone, when given by the intramammary route to the cow are described. Cefoperazone is excreted from the udder over a three- to five-day period following a single infusion of 250 mg in an oil base into each of all four quarters. By the fifth milking after treatment the mean bucket (composite) concentration of cefoperazone was below 0.01 microgram/ml. The minimal inhibitory concentrations for 470 pathogens isolated from cases of mastitis were determined. A few exotic species were resistant but all the usual isolates were sensitive. No signs of transferable drug resistance from known multiple drug-resistant strains were detected.

Incidence and In Vitro Acquisition of Transferable Drug Resistance in Salmonella arizonae

Fifty-eight cultures of Salmonella arizonae isolated in 1983 from poultry sources and 21 cultures isolated in 1972 to 1974 were screened for resistance to nalidixic acid, chloramphenicol, triple sulfa, ampicillin, tetracycline, streptomycin, and kanamycin by the standardized disc susceptibility method. Sensitivity to all seven drugs was observed in 51% of the cultures tested (76% of the older cultures and 41% of the recent isolates). Resistance to two or more drugs was observed in 36% of the cultures tested (14% of the older cultures and 43% of the newer ones). The highest incidence of resistance was to streptomycin.Salmonella arizonae cultures sensitive to all seven drugs were tested for the ability conjugatively to acquire kanamycin, streptomycin, tetracycline, and ampicillin resistance determinants from a multiply resistant strain of Escherichia coli K12NA. Complete or intermediate resistance to all antibiotics was transferred to 93% of the sensitive cultures at 41 C and 85% at 28 C. Kanamycin resistance was transferred most frequently, and ampicillin resistance least frequently.

Plasmid coding for transferable drug resistance in bacteria isolated from cultured rainbow trout.

The occurrence of drug resistance and plasmid-mediated transferability was investigated in 170 strains belonging to eight bacterial groups isolated from cultured rainbow trout. It was found that 87.6% of the strains were resistant to at least one drug, with the highest percentages of resistance being detected for ampicillin (54.7%), sulfadiazine (46.5%), nitrofurantoin (38.2%), and chloramphenicol (37.0%). Six enterobacteria, two Vibrio, and one Aeromonas isolate transferred resistance factors to Escherichia coli K-12. The most common transmissible R factor determined resistance to chloramphenicol and sulfadiazine, demonstrating an association between a specific plasmid and the resistance pattern transferred. The presence of chloramphenicol in fish food was detected by bioassay. In general, transfer frequencies were similar in primary and secondary matings, which indicate the potential water-borne dissemination of these R plasmids.

Promiscuous transfer of drug resistance in gram-negative bacteria.

Bacterial conjugation is a major mechanism for the spread of antibiotic-resistance genes in pathogenic organisms. In gram-negative bacteria, broad-host-range drug-resistance plasmids mediate genetic exchange between many unrelated species. The mechanism of conjugation encoded by the broad-host-range IncP plasmid RK2 has been studied in detail. The location and sequence of the transfer origin of RK2 has been determined. Several barriers limit plasmid transfer between unrelated bacteria: interactions at the cell surface may prevent effective mating contact, restriction systems may degrade foreign DNA, or the plasmid may not replicate in the new host. RK2 has evolved specific mechanisms by which it overcomes these barriers; this plasmid can mediate the transfer of resistance to most gram-negative bacteria.

Plasmid-mediated beta-lactam resistance of Escherichia coli isolated from travellers' diarrhoea in the Far East.

The transfer of drug resistance and beta-lactamase activity of 28 E. coli from travellers' diarrhoea were examined. Plasmid-mediated beta-lactam resistance was found in 18 and at least 3 different types of beta-lactamases were demonstrated.

Transferable Drug Resistance in Escherichia coli Isolated from Antibiotic-Fed Chickens

The isolation and transferable drug resistance of Escherichia coli from the feces of chickens after oral administration of tetracylcine, chloramphenicol, rifampicin, and amoxicillin were studied. Each antibiotic was administered at two different dosages to four groups of 12 chickens. Treatment was carried out for 3 weeks. Feces were taken weekly and bacteriological examinations performed. E. coli biotypes were identified by fermentation and enzymatic reaction patterns. Antibiotic sensitivity tests were performed on all E. coli isolates.Rapid appearance of E. coli biotypes showing drug-resistance to each antibiotic was observed as soon as 1 week after treatment. Resistance was not detectable a few days after interruption of antibiotic administration.All E. coli strains showing drug resistance to the antibiotic under examination were studied to observe their capacity to transfer antibiotic resistance to E. coli K 12 E 711 F-strain. A high percentage of resistant E. coli strains transferred their antibiotic resistance to E. coli K 12. Transferable drug resistance was demonstrated mainly in tetracycline resistant E. coli.

A transposon in Streptococcus faecalis with fertility properties.

Certain strains of streptococci have been shown to be capable of conjugatively transferring drug resistance determinants in the apparent absence of plasmid DNA1–6. The transferrable tetracycline resistance (Tcr) marker of Streptococcus faecalis DS16 has been located on a transposon, designated Tn 9162,4,7. We show here that when chromosomal Tn 916 is conjugatively transferred it inserts into a number of different sites on the recipient chromosome. Our studies also imply that transfer and transposition share a common step, which may be excision of the transposon from the donor chromosome.

DNA-mediated transfer of multiple drug resistance and plasma membrane glycoprotein expression.

Colchicine-resistant Chinese hamster ovary (CHO) cell mutants whose resistance results from reduced drug permeability have been isolated previously in our laboratories. This reduced permeability affects a wide range of unrelated drugs, resulting in the mutants displaying a multiple drug resistance phenotype. A 170,000-dalton cell surface glycoprotein (P-glycoprotein) was identified, and its expression appears to correlate with the degree of resistance. In this study we were able to confer the multiple drug resistance phenotype on sensitive mouse L cells by DNA-mediated gene transfer of DNA obtained from the colchicine-resistant mutants. P-glycoprotein was detected in plasma membranes of these DNA transformants by staining with an antiserum raised against membranes of mutant CHO cells. These results are consistent with a causal relationship between P-glycoprotein expression and the multiple drug resistance phenotype.

DNA-mediated transfer of multiple drug resistance and plasma membrane glycoprotein expression.

Colchicine-resistant Chinese hamster ovary (CHO) cell mutants whose resistance results from reduced drug permeability have been isolated previously in our laboratories. This reduced permeability affects a wide range of unrelated drugs, resulting in the mutants displaying a multiple drug resistance phenotype. A 170,000-dalton cell surface glycoprotein (P-glycoprotein) was identified, and its expression appears to correlate with the degree of resistance. In this study we were able to confer the multiple drug resistance phenotype on sensitive mouse L cells by DNA-mediated gene transfer of DNA obtained from the colchicine-resistant mutants. P-glycoprotein was detected in plasma membranes of these DNA transformants by staining with an antiserum raised against membranes of mutant CHO cells. These results are consistent with a causal relationship between P-glycoprotein expression and the multiple drug resistance phenotype.

Characterization of pBFTM10, a clindamycin-erythromycin resistance transfer factor from Bacteroides fragilis

Bacteroides fragilis TMP10, which is clindamycin-erythromycin resistant (Clnr) and tetracycline resistant (Tetr), contains several plasmids and is capable of transferring drug resistance markers to suitable recipients. We were able to separate a 14.6-kilobase self-transmissible Clnr plasmid, pBFTM10, from the other plasmids of TMP10 in a tetracycline-sensitive recipient strain, B. fragilis TM4000. All Clnr transconjugants acquired an unaltered pBFTM10 and became plasmid donor strains. Transfer is proposed to occur by conjugation since it required to cell-to-cell contact of filter matings and was insensitive to DNase, but sensitive to chloroform treatment of donor cells. The efficiency of transfer of pBFTM10 in a Tets background (TM4003) was not affected by pretreatment of donor cells with clindamycin. A spontaneously occurring Clns derivative, pBFTM10 delta 1, suffered a deletion of DNA, which included a 4.4-kilobase EcoRI fragment. A complex interaction between the autonomous plasmid pBFTM10 and a tetracycline transfer element also present in strain TMP10 was observed since pretreatment of this donor with tetracycline or clindamycin resulted in a marked increase in transfer of both tetracycline and clindamycin resistance.

Transferable drug resistance in streptococci

Transferable drug resistance in streptococci

Plasmids, drug resistance, and gene transfer in the genus Streptococcus.

Plasmids, drug resistance, and gene transfer in the genus Streptococcus.

Factors influencing the establishment and spread of R-plasmids in an experimental model of urinary tract infection.

An experimental model simulating infection of the urinary tract was used to investigate factors influencing the transfer of plasmid-mediated drug resistance in the human bladder in the absence of antibiotic therapy. When a small number of cells carrying plasmid-mediated drug resistance was added to an established population of sensitive cells, it was found that varying the physical conditions of the bladder model had no significant effect on the spread of the plasmid and, under all conditions used, exponential spread of the plasmid through the originally sensitive population occurred. When the initial donor cells were killed shortly after addition to the model, exponential transfer of resistance amongst the established sensitive population still occurred. Thus, even in the absence of antibiotic therapy, only a small number of initial transfer events was required for a fully resistant population to be developed. This was true of both actively multiplying and early stationary phase cultures. An initially greater proportion of resistant cells, or the use of an antimicrobial agent to which some of the cells are resistant, would ensure that this process occurred more rapidly.

Plasmids, drug resistance, and gene transfer in the genus Streptococcus.

Plasmids, drug resistance, and gene transfer in the genus Streptococcus.

Mechanisms of drug-resistance transfer in Bacteroides fragilis.

Mechanisms of drug-resistance transfer in Bacteroides fragilis.

Infective drug resistance among Escherichia coli isolated from clinically healthy domestic livestock

A total of 414 Escherichia coli isolates from faecal swabs of clinically healthy kids, piglets, chickens, calves and lambs was tested for drug resistance, and for transferable drug resistance to eight antimicrobial agents. One hundred and twenty-nine isolates (31.15%) transferred part or whole of their resistance determinants to a sensitive recipient. Chloramphenicol resistance was not common; only three of the 13 chloramphenicol resistant isolates transferred their resistance to E. coli J5 K 12. Of the 19 resistance patterns seen, OTSUS resistance, which occurred in 104 (25%) of the isolates, was most common. It is suggested that an antimicrobial drug like furazolidone should be substituted for the tetracyclines as a feed additive.

Colicinogenicity of Escherichia coli Isolates from Healthy and Diarrhoeic Goats

A total of 550 E. coli isolates--250 from apparently healthy, and 300 from diarrhoeic West African pigmy goats were tested for colicinogenicity. 33.2% of strains from apparently healthy animals were colicinogenic as against 56% recorded for strains from animals with diarrhoea. Of the 251 colicinogenic E. coli strains from both groups of animals, 76.5% were Type I while 23.5% belonged to Type II. Identified colicins from the healthy animals consisted of types G, K, E2, A and V in decreasing frequency of occurrence, whereas those from goats with diarrhoea were made up of types V, B, E1, G, E2, E3, and Ia also in decreasing frequency of occurrence. In contrast to isolates from healthy animals, there was a marked variation in the colicin spectra of Types I and II E. coli from the diarrhoeic animals--that of Type I being much broader. The Public Health significance of possible transfer of multiple drug resistance from colicinogenic E. coli strains to other enterobacteria is also discussed.

Plasmids in Escherichia coli controlling citrate-utilizing ability

The citrate-utilizing ability of 19 out of 22 citrate-positive Escherichia coli strains isolated from pig sewage was transferred via conjugation to E. coli K-12. The conjugal transfer of citrate-utilizing (Cit) abilities was thermosensitive and concurrent with transfer of drug resistance. Weakly citrate-positive colonies were readily obtained in conjugation experiments. Their Cit characters could be transmitted to the other E. coli strains at a similar frequency in the retransfer experiments, and the transconjugants obtained still showed same characteristic growth on Simmons citrate agar plates. The 19 thermosensitive plasmids conferring citrate utilization and drug resistance were Fi-, and 16 of these plasmids belonged to incompatibility group H1. However, occasionally two conjugative plasmids (pOH3122-1 and pOH3124-1) carrying only the citrate utilization were also obtained in the conjugation experiments, and they were Fi+ and compatible with 19 reference R plasmids. In the two citrate-positive E. coli strains, it was suggested that the conjugative Cit plasmid showing Fi+ character and the more thermosensitive H1 plasmid conferring both the Cit character and drug resistance coexisted in the strain. The characterization of citrate utilization plasmids derived from pig farm sewage is discussed.

Eimeria maxima: the use of enzyme markers to detect the genetic transfer of drug resistance between lines

Eimeria maxima (Weybridge) and E. maxima (indentata) were distinguished by the electrophoretic mobility of phosphoglucomutase. This enzyme was used as a marker to detect the transfer of methyl benzoquate resistance between resistant and sensitive lines of these parasites.

Drug Resistance in Strains of Escherichia Coli Isolated from the Intestinal Tract of Pigs in Norway

Faecal samples from 95 healthy pigs and samples of jejunal content from 85 piglets suffering from colienterotoxaemia were tested for the presence of drug resistant E. coli strains. Practically all pigs in both groups harboured E. coli strains resistant to one or more of the 6 antibiotics/chemotherapeutic agents tested (Oxytetracycline, streptomycin, sulphaisodimidin, neomycin, ampicillin, chloramphenicol). Almost 100% of healthy and approx. 90% of diseased pigs harboured strains resistant to Oxytetracycline, streptomycin and sulphaisodimidin. Pigs with strains resistant to neomycin, ampicillin and chloramphenicol were less frequently found. The predominant coliform flora consisted of E. coli strains” resistant to Oxytetracycline, streptomycin and sulphaisodimidin in 71% to 81% of diseased pigs and in 47% to 69% of the healthy pigs. In diseased pigs ¾ of the animals had a coliform flora dominated by neomycinresistant E. coli strains. Of the 721 resistant E. coli strains isolated from healthy pigs, 11% were single resistant while the corresponding figure for the 518 resistant strains isolated from diseased pigs was 6%. Thus 89% and 94% of strains showed simultaneous resistance to 2 or more antibiotics. E. coli strains resistant to 3 or more drugs were found in approx. 60% and 70% of the isolates from healthy and diseased animals, respectively. Oxytetracycline/streptomycin/sulphaisodimidin resistance was most commonly found, approx. 22% and 38% of the strains from healthy and diseased pigs, respectively, showing this resistance pattern. Transmission of drug resistance which was examined in E. coli strains originating from the diseased pigs was demonstrated in approx. 76% of the isolates. The incidence of drug resistance transfer in single, double, triple and quadruple resistant strains was 11%, 68%, 97% and 98%, respectively.