Incidence Of Resistant Strains Research Articles

Treatment of Helicobacter pylori infections in the light of the increase of antibiotic resistance

The aim of this study was to present the risks associated with the occurrence of Helicobacter pylori (H. pylori) infection in humans and the problems related to eradication procedures with the use of antibiotic treatment. The content provides an overview of the available methods of infection diagnosis and recommended therapeutic schemes as well as potential alternative schedules of treatment. Mechanisms of H. pylori resistance to commonly used antibiotics including the mutations in the genome leading to resistance and the incidence of resistant strains in the world has been described. Finally, we introduced substances with some potential in eradication therapy, including probiotics, plant formulations as well as polyunsaturated fatty acids and ascorbic acid.

Intensive care antibiotic consumption and resistance patterns: a cross-correlation analysis

BackgroundOver recent decades, a dramatic increase in infections caused by multidrug-resistant pathogens has been observed worldwide. The aim of the present study was to investigate the relationship between local resistance bacterial patterns and antibiotic consumption in an intensive care unit in a Romanian university hospital.MethodsA prospective study was conducted between 1st January 2012 and 31st December 2013. Data covering the consumption of antibacterial drugs and the incidence density for the main resistance phenotypes was collected on a monthly basis, and this data was aggregated quarterly. The relationship between the antibiotic consumption and resistance was investigated using cross-correlation, and four regression models were constructed, using the SPSS version 20.0 (IBM, Chicago, IL) and the R version 3.2.3 packages.ResultsDuring the period studied, the incidence of combined-resistant and carbapenem-resistant P. aeruginosa strains increased significantly [(gradient = 0.78, R2 = 0.707, p = 0.009) (gradient = 0.74, R2 = 0.666, p = 0.013) respectively], mirroring the increase in consumption of β-lactam antibiotics with β-lactamase inhibitors (piperacillin/tazobactam) and carbapenems (meropenem) [(gradient = 10.91, R2 = 0.698, p = 0.010) and (gradient = 14.63, R2 = 0.753, p = 0.005) respectively]. The highest cross-correlation coefficients for zero time lags were found between combined-resistant vs. penicillins consumption and carbapenem-resistant P. aeruginosa strains vs. carbapenems consumption (0.876 and 0.928, respectively). The best model describing the relation between combined-resistant P. aeruginosa strains and penicillins consumption during a given quarter incorporates both the consumption and the incidence of combined-resistant strains in the hospital department during the previous quarter (multiple R2 = 0.953, p = 0.017). The best model for explaining the carbapenem resistance of P. aeruginosa strains based on meropenem consumption during a given quarter proved to be the adjusted model which takes into consideration both previous consumption and incidence density of strains during the previous quarter (Multiple R2 = 0.921, p = 0.037).ConclusionsThe cross-correlation coefficients and the fitted regression models provide additional evidence that resistance during the a given quarter depends not only on the consumption of antibacterial chemotherapeutic drugs in both that quarter and the previous one, but also on the incidence of resistant strains circulating during the previous quarter.

PHYTOPHTHORA INFESTANS POPULATIONS FROM THE EUROPEAN PART OF RUSSIA: GENOTYPIC STRUCTURE AND METALAXYL RESISTANCE

Populations of the potato and tomato late blight pathogen from different regions of the European part of Russia were studied for their genotypic structure and metalaxyl resistance. The majority of the studied populations showed a high genotypic diversity, i.e. strains of A1 and A2 mating types, Ia and IIa mitochondrial DNA haplotypes, and different genotypes at Pep1 and Pep2 loci were identified. The highest genotypic diversity was registered among P. infestans populations from the North Caucasus, Mariy El Republic, and the Moscow region. The obtained data confirm a high probability of crossing and hybridization within the most part of the field populations of P. infestans from the European part of Russia. Most of the studied populations included strains with high and low metalaxyl resistance, the incidence of resistant strains depending on the use of metalaxyl-containing fungicides.

Étiologie des infections bactériennes chez les patients neutropéniques fébriles: Rôle du laboratoire dans le diagnostic

EPIDEMIOLOGICAL EVOLUTION: Until the mid-eighties, infectious complications (pneumonia, septicemia) observed in neutropenic patients were, in 70% of cases, of bacterial origin with Gram negative bacillae (Escherichia coli, Klebsiella sp, Pseudomonas aeruginosa) isolated 8 times out of 10. Among the Gram positive bacteria, Staphylococcus aureus predominated. The etiological profile of bacterial infections has since evolved with a predominance (60 to 70%) of Gram positive bacteria (coagulase-negative staphylococci, viridans streptococci) and a change in the epidemiology of the Gram positive bacteria notably with a lesser frequency of P. aeruginosa infections. THE GRAM POSITIVE BACTERIA: Coagulase-negative staphylococci are among the first germs responsible for nosocomial bacteremia (central venous catheters) and they are usually multiresistant. Viridans streptococci are a frequent cause of bacteremia; they are generally sensitive to antibiotics active on Gram positive bacteria, but the incidence of resistant strains is increasing. Enterococci are in majority responsible for colonisation in neutropenic patients and less frequently for infections; they raise the problem of resistance to antibiotics, notably to glycopeptides. Other Gram positive bacteria can be responsible for infections in neutropenic patients; it is crucial that they be identified because they require treatment with an appropriate antibiotic. GRAM NEGATIVE BACTERIA: Among the enterobacteria, Escherichia coli is predominantly isolated and raises the problem of the increasing incidence of resistance to fluoroquinolone. Pseudomonas aeruginosa, less frequently responsible today, remains associated with a far greater rate of mortality than that observed with the other microorganisms. Other Gram negative bacteria can be identified; they require an adapted antibiotherapy because they are often naturally multiresistant to antibiotics. THE ROLE OF THE LABORATORY: For the diagnosis of infections in neutropenic patients, the microbiology laboratory has a determinating role. The laboratory ensures the analysis of various biological examinations: blood cultures, methods permitting the diagnosis of an infection on a permanent catheter, copro-cultures (research for common enteropathogens, quantification in the case of digestive decontamination, screening for multiresistant bacteria), cytobacteriological examination of urine, samples of respiratory origin, cytobacteriological examination of cerebro-spinal fluid...).

Comparison of Clarithromycin and Amoxicillin/Clavulanic Acid for Community-Acquired Pneumonia in???an Era of Drug-Resistant Streptococcus pneumoniae

To compare the safety and efficacy of clarithromycin and amoxicillin/clavulanic acid in patients with community-acquired pneumonia due to penicillin-resistant and/or macrolide-resistant Streptococcus pneumoniae, by selecting clinical investigators who practice in study populations from geographic areas in which a high incidence of resistant strains is reported by surveillance. Prospective, randomised, investigator-blinded, multicentre study conducted in 45 sites in primary-care and referral centre settings. 327 ambulatory patients diagnosed with radio-graphically confirmed community-acquired pneumonia administered clarithromycin 500mg immediate-release or amoxicillin/clavulanic acid 875mg/125mg twice daily for 7 days. Similarly high clinical cure rates were observed among evaluable patients in both treatment groups at the test-of-cure visit (28-35 days post-treatment): 92% (114/124) for clarithromycin and 91% (117/129) for amoxicillin/clavulanic acid. Of 85 S. pneumoniae strains isolated pretreatment, four (5%) were classified as resistant to macrolides (one mefA, two ermB, and one ermB + mefA) and eight (9%) had reduced susceptibility to penicillin. The overall eradication rate for pathogens isolated from bacteriologically and clinically evaluable patients was 91% for clarithromycin and 93% for amoxicillin/clavulanic acid, and 89% and 92%, respectively, for S. pneumoniae strains. The rates of resolution and/or improvement in clinical signs and symptoms and radiological improvement were similar with clarithromycin to those with amoxicillin/clavulanic acid, as was overall incidence of adverse events. A 7-day course of clarithromycin immediate-release was similar to amoxicillin/clavulanic acid based on high rates (>90%) of clinical cure, radiological improvement and pathogen eradication among ambulatory-care patients with community-acquired pneumonia. As the resistance rate at baseline was low, no conclusion could be made about clarithromycin's efficacy for infections caused by macrolide-resistant S. pneumoniae. Both treatments were well tolerated.

Epidemiological survey for hemolytic streptococci isolated from children in Tokyo

During the 20-year period between 1979-1998, a total of 4,176 strains of hemolytic streptococci have been isolated from 20,118 healthy primary school children and little children in Tokyo Metropolitan (Tokubetsuku, Tama and Tosho). Culture of throat swabs every November and the following February during the 20-year period were made and serological grouping and typing for isolates were done by T agglutination method. The results were as follows. 1) Serological group of hemolytic streptococci isolated from children were 3,188 strains (76.3%) for isolates of group A out of total strains of 4,176, 569 strains (13.6%) for isolates group B, 63 strains (1.5%) for isolates of group C and 356 strains (8.5%) for isolates of group G. 2) The most dominant was T12 during 1979-1998, and other relatively frequent serotypes were T28, T1, T4, T6 in that order. These ranks of and the main epidemic serotypes showed a similar trend in the 3 areas. 3) The isolation rates of group A streptococci were 15.9% in Tokubetsuku, 17.1% in Tama and 14.9% in Tosho. The average of 3 areas were 15.8%. 4) The epidemic cases seemed to be caused by group A streptococci were 20 cases, their isolated serotype were 7 cases by T28, 5 cases by T12, 4 cases by T6, 2 cases by T4, each 1 case by T1 and T25. 5) A total of 2,927 strains of group A streptococci were examined for drug sensitivity. All strains were sensitive to beta-lactam group of antibiotics (benzylpenicillin and cephaloridine). Resistant (MIC > or = 25 micrograms/ml) to TC, CP and EM etc. were 740 strains (25.3%) in this study. The incidence of resistant strains were to TC 493 strains (66.6%) out of 740 strains, 81 strains (10.9%) for TC.CP, 72 strains (9.7%) for EM and 66 strains (8.9%) for TC.CP.EM.OL.LCM. TC resistant strains have not varied much through the whole period, but CP and EM resistant strains were very variable by year. Many resistant strains to TC were T4, to EM and multiple drug resistant were T12. 6) The rates of isolates of the same type of group A streptococci in school child individual during for the tests taken twice a year were 12.3%, indicating group A streptococci, according to the duration of the carrier state, seems to be a short period.

Laboratory-based surveillance of Salmonella serotype Typhi infections in the United States: antimicrobial resistance on the rise.

Multidrug-resistant Salmonella serotype Typhi infections have been reported worldwide, but data on the incidence of resistant strains in the United States are lacking. To determine the incidence of antimicrobial-resistant Salmonella Typhi infections and to identify risk factors for infection. Cross-sectional laboratory-based surveillance study. A total of 293 persons with symptomatic typhoid fever who had Salmonella Typhi isolates and epidemiological information submitted to US public health departments and laboratories from June 1, 1996, to May 31, 1997. Proportion of Salmonella Typhi isolates demonstrating resistance to 12 antimicrobial agents; patient epidemiological factors associated with drug-resistant infections. Median age was 21 years (range, 3 months to 84 years); 56% were male. Two hundred twenty-eight (80%) were hospitalized; 2 died. In the 6 weeks before illness onset, 81% of patients had traveled abroad. Seventy-four Salmonella Typhi isolates (25%) were resistant to 1 or more antimicrobial agent, and 51 (17%) were resistant to 5 or more agents, including ampicillin, chloramphenicol, and trimethoprim-sulfamethoxazole (multidrug-resistant Salmonella Typhi [MDRST]). Although no resistance to ciprofloxacin or ceftriaxone was observed, 20 isolates (7%) were nalidixic acid-resistant (NARST). Patients with MDRST and NARST infections were more likely to report travel outside the United States, particularly to the Indian subcontinent (Bangladesh, India, and Pakistan) (odds ratio [OR], 29.3; 95% confidence interval [CI], 6.8-126.7; P<.001 and OR, 35.9; 95% CI, 3.4-377.3; P<.001, respectively). Our data suggest that ciprofloxacin and ceftriaxone are appropriate empirical therapy for suspected typhoid fever; however, resistance may be anticipated. Continued monitoring of antimicrobial resistance among Salmonella Typhi strains will help determine vaccination and treatment policies. JAMA. 2000;283:2668-2673.

Positive correlation between the age of patients and the degree of antimicrobial resistance among urinary strains of Escherichia coli

We have studied the resistance of urinary strains of Escherichia coli in relation to patients' age. A total of 4146 samples of urine was collected during 1984-1990 from patients staying in an acute care university hospital and in a long-term care city hospital in Finland. In the city hospital, the proportion of strains resistant to either ampicillin, trimethoprim, sulphonamides, or to all of these simultaneously (multi-resistant), correlated with increase in age of the patients. In the university hospital, a clear increase was observed in trimethoprim-resistant and multiresistant isolates. Such correlation with age was not observed among catheterised patients in either hospital. Whether this is due to cumulative lifetime use of antimicrobials remains to be studied. We conclude that the incidence of resistant strains of E. coli correlates with patients' age among both chronic and acute care patients who are not catheterised. This is important in the choice of empirical treatment for urinary tract infections of elderly people.

Resistance to cefsulodin and gentamicin in Pseudomonas aeruginosa strains in five areas of Japan between 1980 and 1983

The activities of cefsulodin and gentamicin against Pseudomonas aeruginosa isolated from clinical specimens from five hospitals in different geographical areas of Japan, from 1980 to 1983, were compared in vitro. The incidence of resistant strains was higher for gentamicin. In 1982 the sensitivity to both drugs decreased from 1980 and 1981 levels, largely because of the isolation of numbers of cefsulodin-gentamicin cross-resistant bacteria from three of the five hospitals. In 1983, the incidence of resistant strains was similar to that in 1982. This linked cefsulodin-gentamicin resistance may have been selected by the use of the cephalosporins, cefmenoxime, cefoperazone, cefotaxime, ceftizoxime and latamoxef, which had been prescribed extensively in the hospitals where cross-resistance was encountered. Although cefsulodin-resistant strains of P. aeruginosa have increased since 1982, the in-vitro activity of cefsulodin in 1983 remained greater than that of these third-generation cephalosporins.

Antibiotic-resistant coliforms in the waste of piggeries and dairy farms.

To examine for incidence of coliforms and drug-resistant Escherichia coli, a total of 22 swine and 19 bovine waste samples were collected from eight piggeries and nine dairy farms in Japan in 1976 and 1977. Chemical oxygen demand (COD), suspended solid (SS), pH values, and the number of coliforms with or without antibiotic resistance were measured to analyze for the correlation function. Except the correlation between the coliform count and the pH value of bovine urine storage samples, no significant correlation was observed. Coliforms in bovine urine storage samples of alkalinity were fewer than other samples. It was shown that the waste treatment on a piggery (farm E) was effective in decreasing COD and coliforms in the waste. A total of 449 (97%) of 465 E. coli strains isolated from swine samples and 180 (78%) of 230 strains from bovine samples were resistant to at least one of the followings ; ampicillin, furatrizine, chloramphenicol, kanamycin, streptomycin(Sm), sulfonamide(Su) and tetracycline(Tc). Resistance to Tc, Sm and Su was common in E.coli strains from swine and bovine samples but incidence of resistant strains from swine samples was generally higher than that from bovine samples. The drug resistance patterns (47 patterns) of swine E. coli strains were more complicated than those (24 patterns) of bovine strains. Conjugative R plasmids were detected in swine (56%) and bovine samples (33%). Thirteen (22%)thermosensitive R plasmids were found only in swine samples. Animal waste heavily contaminated with drug resistant coliforms can be a potential source of environmental pollution.

Seasonal Change of the Incidence of Resistant Strains of E. Coli to Antimicrobials

Seasonal Change of the Incidence of Resistant Strains of E. Coli to Antimicrobials

A 6-year survey of resistance patterns of urinary tract pathogens in general practice

Summary A survey of resistance patterns of urinary pathogens causing infections in general practice over the period 1964-69, including 3100 cases of which 2718 were caused by Bacterium coli, Proteus species or coliform organisms has been made. The resistance patterns of the enterobacteria have been examined and reveal a rise in incidence of sulphonamide-resistant strains from 1964 to a peak of 61·3% in 1967 followed by a symmetrical fall to return to 24·9% in 1969. Ampicillin and nalidixic acid were the only two drugs of twelve to show a constant rise in incidence of resistant strains although the figures are much lower reaching peaks of 11·1% in 1969 for ampicillin and 3·2% in 1969 for nalidixic acid. The other drugs surveyed show less definite change; tetracycline constantly shows an incidence of about 30% resistance and nitrofurantoin varies between 2·7% and 8·7%. Low incidences of resistance against trimethoprim-sulphonamide mixture are recorded: 1·5% in 1968 and 2·0% in 1969. Proteus strains, treated separately, frequently show resistance to tetracycline, 90·3% in 1969, and to nitrofurantoin, 37·8% in 1969. The incidence of multiple resistance is also increasing. Fifty-three percent of strains were resistant to at least one antibiotic and 6% to three or more in the period 1964-67 and 57·3% show resistance to at least one drug and 10·3% to three or more in the period 1967-69.

Eperience with oral rifampicin in respiratory act infecti, arlet fever and bacillary dysentery

Eleven adults with respiratory tract infections, sixteen infants with scarlet fever and twenty-seven patients with bacillary dysentery were treated with Rifampicin (RF) in a study to evaluate clinical effectiveness of the drug, with the results which may be summarized as follows1) The treatment was effective in 7 of the 11 cases of respiratory tract infections (pneumonia, bronchitis and angina follicularis) and failed to produce any significant symptomatic amelioration in 4 cases, indicating the medication to be not particularly superior to the conventional chemotherapeutic agents in these categories of diseases.2) Of the 16 infants with scarlet fever admitted to the present study, 14 eventually provided adequate clinical data for clinical evaluation. Ten of the 14 responded with significant clinical improvement, and the treatment was ineffective in the remaining 4 patients. In comparison with the clinical response in previously experienced cases of the same condition treated similarly but with several other antibiotics, the response of the children to the Rifampicin therapy was found to be less clinically beneficial than intramuscular penicillin therapy, to be practically comparable in efficacy to Clindamycin administration and to be more effective than treatment with Bicillin, EM, TC, or Spiramycin.3) Significant clinical benefit from the use of Rifampicin was evident in 7 of the adults with bacillary dysentery and in 17 of the 19 children with the same disease. The results stress chinical effectiveness of Rifampicin in this disease state for therapy with no concomitant medications. Those, however, who had failed to display complete arrest of bacillary excretion in the feces following institution of the drug continued to excrete the organism. This was the finding rather characteristic of the response to Rifampcin therapy. There was one infantile case among the 19 studied, in which laboratory and clinical data suggested emergence of drug resistance in the population of the pathogen involved. Detailed accounts are given with respect to the clinical course of this patient.4) Growing decrease in clinical efficacy in bacillary dysentery of colimycin which has seen practically no increase in incidence of resistant strains in vitro is pointed out. Further evaluation of Rifampcin therapy, in this context, as to dosage, duration and advisable concomitant chemotherapy especially with drugs not readily absorbed from the gastrointcstinal tract rcmains to be pursued.

RESISTANCE OF SALMONELLAE ISOLATED IN 1962 TO TETRACYCLINE, CHLORAMPHENICOL, AND AMPICILLIN.

Of 664 Salmonella cultures isolated during 1962 from a variety of sources in Canada, 56 (8.4%) were resistant to one or more of the antibiotics tetracycline, chloramphenicol, and ampicillin. Of the 38 serotypes studied, S. typhimurium and S. heidelberg showed a much higher proportion of strains resistant to tetracycline than did the other serotypes. The incidence of resistant strains among 335 cultures from man was 6.9%; among 74 strains from poultry, 35.1%; while among 52 strains from other animal sources only 5.8% were resistant.

The Ability of Low Concentrations of Chemotherapeutic Substances to Induce Resistance in E. coli

SUMMARY Examination of 37 cultures of E. coli isolated from chickens originating from different farms showed 8 to be resistant to chlortetracycline. Resistance to streptomycin, furazolidone and chloramphenicol was relatively infrequent. It was found that a marked increase in resistance of these strains of E. coli could be produced within 7 days to chlortetracycline, streptomycin and furazolidone, by a technique of repetitive training involving serial subculture in media containing low concentrations of antibiotic. The association between these findings and the administration of antibiotics in poultry foods is discussed. Strains of E. coli which had acquired resistance to chlortetracycline, furazolidone and streptomycin were found, in the majority of cases, to have retained this resistance over a period of 28 days of serial subculture in an antibiotic free medium. This finding was in agreement with the results of tests on chicks in which the resistance of intestinal E. coli to chlortetracycline, after removal of this antibiotic from the food, persisted undiminished throughout the 14 days of observation. The incidence of resistant strains in these chicks after removal of antibiotic from the food, however, was found to be influenced by the incidence of sensitive strains in the environment of the chicks. The significance of these findings on the persistence of resistant strains in chicks after withdrawal of antibiotic from the food is discussed. Chloramphenicol was found to act in a different manner from the other antibiotics tested, in that resistance to it was not readily induced by repetitive training, and acquired resistance was rapidly lost.

Studies on the antibiotic-susceptibility of the isolates from staphylococcal infections.

The antibiotic susceptibility of 500 strains of staphylococcus aureus isolated from the patients with surgical suppurative diseases from December, 1957 to March, 1961 was studied. The results obtained will be summarized as follows: 1) Only a few strains were inhibited by a low concentration of penicillin. On the contrary, the majority of the strains were inhibited by a low concentration of erythromycin. Distribution curves of susceptibility to streptomycin, chloramphenicol and tetracycline lay between those of penicillin and erythromycin. The incidence of the resistant strains to five antibiotics was, in the order of frequency, 58.2 per cent to penicillin, 37.2 per cent to streptomycin, 18.8 per cent to tetracycline, 6.8 per cent to chloramphenicol and none to erythromycin. Multiple resistant strains numbered 165, the majority of them being resistant to both penicillin and streptomycin. 2) Environmental and geographical influence on staphylococcal susceptibility was studied with three different groups of strains. With streptomycin and tetracyclin, there was a distinct difference between the strains isolated from hospitalized patients of our clinic and the strains isolated from the out-patients of suburban hospitals, the incidence of resistant strains being remarkably high in the former. With chloramphenicol, a considerable number of the strains isolated from hospitalized patients of our clinic required a high concentration for inhibition, although not so remarkable as with streptomycin and tetracycline. With penicillin and erythromycin, there was no remarkable difference in the susceptibility of staphylococci among the three groups. 3) Of the 133 strains isolated from the hospitalized patients of our clinic, the susceptibility of 50 strainss isolated between May, 1958 and January, 1959 and of 50 strains isolated between July, 1959 and March, 1961 were compared. The penicillin resistant strains moderately increased, whereas with strep-tomycin and erythromycin, no significant changes were seen between the two groups. With chloramphenicol and tetracycline, no increase in the incidence of resistant strains was seen, but a decrease of sensitive strains and an increase of moderately resistant strains were seen in the lately isolated group. 4) As for the changes of the susceptibility of staphylococci after administration of a large amount of antibiotics, a decrease of sensitive strains and an increase of resistant strains were seen with every one of five antibiotics, the tendency being most remarkable with streptomycin.