Tetracycline Erythromycin Research Articles

National Surveillance of Tetracycline, Erythromycin, and Clindamycin Resistance in Invasive Streptococcus pyogenes: A Retrospective Study of the Situation in Spain, 2007-2020.

This work reports on antimicrobial resistance data for invasive Streptococcus pyogenes in Spain, collected by the 'Surveillance Program for Invasive Group A Streptococcus', in 2007-2020. emm typing was determined by sequencing. Susceptibility to penicillin, tetracycline, erythromycin, and clindamycin was determined via the E-test. tetM, tetO, msrD, mefA, ermB, ermTR, and ermT were sought by PCR. Macrolide-resistant phenotypes (M, cMLSB, and iMLSB) were detected using the erythromycin-clindamycin double-disk test. Resistant clones were identified via their emm type, multilocus sequence type (ST), resistance genotype, and macrolide resistance phenotype. Penicillin susceptibility was universal. Tetracycline resistance was recorded for 237/1983 isolates (12.0%) (152 carried only tetM, 48 carried only tetO, and 33 carried both). Erythromycin resistance was detected in 172/1983 isolates (8.7%); ermB was present in 83, mefA in 58, msrD in 51, ermTR in 46, and ermT in 36. Clindamycin resistance (methylase-mediated) was present in 78/1983 isolates (3.9%). Eight main resistant clones were identified: two that were tetracycline-resistant only (emm22/ST46/tetM and emm77/ST63/tetO), three that were erythromycin-resistant only (emm4/ST39/mefA-msrD/M, emm12/ST36/mefA-msrD/M, and emm28/ST52/ermB/cMLSB), and three that were tetracycline-erythromycin co-resistant (emm11/ST403/tetM-ermB/cMLSB, emm77/ST63/tetO-ermTR/iMLSB, and emm77/ST63/tetM-tetO-ermTR/iMLSB). Tetracycline, erythromycin, and clindamycin resistance rates declined between 2007 and 2020. Temporal variations in the proportion of resistant clones determined the change in resistance rates.

Antimicrobial resistance and virulence-related genes of Streptococcus obtained from dairy cows with mastitis in Inner Mongolia, China

Context: Mastitis is the most expensive disease in the dairy cattle industry and results in decreased reproductive performance. Streptococcus, especially Streptococcus agalactiae, possesses a variety of virulence factors that contribute to pathogenicity.Objective: Streptococcus isolated from mastitis was tested to assess the prevalence of antimicrobial resistance and distribution of antibiotic resistance- and virulence-related genes.Materials and methods: Eighty-one Streptococcus isolates were phenotypically characterized for antimicrobial resistance against 15 antibiotics by determining minimum inhibitory concentrations (MIC) using a micro-dilution method. Resistance- and virulence-related genes were detected by PCR.Results: High percentage of resistance to β-lactams, along with tetracycline and erythromycin, was found. Resistance to three or more of seven antimicrobial agents was observed at 88.9%, with penicillin–tetracycline–erythromycin–clindamycin as the major profile in Streptococcus isolates. Resistant genes were detected by PCR, the result showed that 86.4, 86.4, 81.5, and 38.3% of isolates were mainly carrying the pbp2b, tetL, tetM, and ermB genes, respectively. Nine virulence genes were investigated. Genes cyl, glnA, cfb, hylB, and scaA were found to be in 50% of isolates, while 3.7, 21, and 4.9% of isolates were positive for bca, lmb, and scpB, genes, respectively. None of the isolates carried the bac gene.Discussion and conclusion: This study suggests the need for prudent use of antimicrobial agents in veterinary clinical medicine to avoid the increase and dissemination of antimicrobial resistance arising from the use of antimicrobial drugs in animals.

Inhibitory effect of erythromycin, tetracycline and sulfamethoxazole antibiotics on anaerobic treatment of a pharmaceutical wastewater.

Pharmaceuticals enter ecosystems, which causes changes to microbial community structure and development of resistant genes. Anaerobic treatments can be an alternative application for treatment of pharmaceutical wastewaters, which has high organic content. This study aims to develop an understanding of the effects of sulfamethoxazole-erythromycin-tetracycline (ETS), sulfamethoxazole-tetracycline (ST), erythromycin-sulfamethoxazole (ES) and erythromycin-tetracycline (ET) combinations on the anaerobic treatment of pharmaceutical industry wastewater. The results of this investigation revealed that bacteria have a competitive advantage over archaea under all antibiotic combinations. The ET reactor showed a better performance compared to other reactors; this could be due to antagonistic effects of sulfamethoxazole. Acute inhibition in the microbial community was also strongly affected by antibiotics concentrations. This indicated that the composition of the microbial community changed in association with anaerobic sequencing batch reactor performances. The results of this research support the idea that an acute test could be used to control and improve the anaerobic treatment system.

The joint acute effect of tetracycline, erythromycin and sulfamethoxazole on acetoclastic methanogens.

In this study, we aimed to develop an understanding of the triple effects of sulfamethoxazole-erythromycin-tetracycline (ETS) and the dual effects of sulfamethoxazole-tetracycline (ST), erythromycin-sulfamethoxazole (ES) and erythromycin-tetracycline (ET) on the anaerobic treatment of pharmaceutical industry wastewater throughout a year of operation. Concentrations of the antibiotics in the influent were gradually increased until the metabolic collapse of the anaerobic sequencing batch reactors (SBRs), which corresponded to ETS (40 + 3 + 3 mg/L) and ST (25 + 2.5 mg/L), ET (4 + 4 mg/L) and ES (3 + 40 mg/L). Acetate accumulation in the anaerobic SBRs, acetoclastic activity of the anaerobic sludge taken from different antibiotic feeding stages and also expression of acetyl-coA synthetase from the acetoclastic methanogenic pathway on the mRNA level were assessed. The results indicated that, while acetate accumulation and decrease of acetoclastic activity were observed after stage 3 in the ST and ES reactors, and stage 7 in the ETS and ET reactors, the expression of acetyl-coA synthetase was mostly decreased in the last stages in all SBRs, in which antibiotic mixture feeding was terminated. It might be speculated that acetoclastic methanogens have an important role in acetate degradation by expressing acetyl-coA synthetase.

The Effects of Egg Stocking Density and Antibiotic Treatment on Survival and Development of Winged Pearl Oyster (Pteria Penguin, Röding 1798) Embryos

Pteria penguin is an important commercial bivalve species that is used in the production of half pearls known as mabè. Expansion of this industry in places with low natural spatfall is reliant on hatchery production of juvenile oysters, which begins with the incubation of fertilized eggs. This study addresses the issue of mortality during egg incubation by examining the effects of egg stocking density and the application of antibiotics. A factorial experimental design was implemented combining 3 egg densities (10, 50, and 100/mL) and 3 antibiotic treatments (control, no antibiotic; 5 mg/mL streptomycin—sulfate; 5 mg/mL tetracycline—erythromycin 2.5:2.5 mg/mL). Antibiotics were added to the culture medium as a single dose and fertilized eggs were incubated for an industry standard period of 24 h. Despite a 23% increase in mean survival during incubation, aquaria treated with tetracycline—erythromycin (1:1) yielded an average of only 9% more veliger larvae than control aquaria as a result of interference with development during the transition of trochophore to shelled larvae (D-stage). Application of the antibiotic streptomycin—sulfate improved mean survival by 16% compared with control aquaria, without significantly compromising development. A high egg density of 100/mL did not significantly reduce survival, but resulted in a 5% reduction in normal development to D-stage. The results of this study show that if tank space is limited during egg incubation, utilizing a high stocking density of 100 eggs/mL will provide the greatest number of D-stage larvae. However, if the supply of eggs is limited, we recommend stocking P. penguin eggs at a density ≤50/mL and minimizing mortality by treating the culture medium with the antibiotic streptomycin—sulfate.

Differential sensitivity to antibiotics of trp mRNA synthesis originating at the trp promoter and the λ promoter

Transcription of the Escherichia coli trp operon translocated into the early region of bacteriophage λ can occur under the control of either of two promoters, the trp promoter or the λ promoter ( P L of N gene). (Imamato, F. and Tani, S. (1972) Nat. New Biol. 240, 172–175 and Ihara S. and Imamoto, F. (1976) Biochim. Biophys. Acta 432, 199–211). trp mRNA synthesis originating at the trp promoter stopped when translation was blocked by chloramphenicol tetracycline erythromycin or puromycin. In contrast, trp mRNA synthesis originating at the λ promoter was not affected by antibiotic action. This probably is a reflection of the properties of the “immediate early” class of genes of λ, whose transcription is initiated at the P L promoter and is not inhibited by the antibiotic. The inference is strengthened by comparable results with phage λ trpE-A (carrying an intact trp operon) and λ trpBA (carrying the operator-distal two genes but missing the trp promoter and operator). Thus it seems that either the promoter or other gene(s) located at the beginning of the operon, either at polymerase addition or because of some feature of the transcript, can determine a requirement for “coupling” of RNA polymerase to the translational machinery in vivo.

Studies on the control of development. Accumulation of guanosine tetraphosphate and pentaphosphate in response to inhibition of protein synthesis in Bacillus subtilis.

Bacillus subtilis cells accumulate unusual phosphorylated substances at the end of logarithmic growth in a semi-synthetic medium. Two of these substances are guanosine 3'(2')-diphosphate 5'-diphosphate (ppGpp) and guanosine 3'(2')-diphosphate 5'-triohosphate (pppGpp) which, in contrast to amino-acid-starved Escherichia coli cells, are not degraded in sporulating cells of B. subtilis after the addition of chloramphenicol. Moreover, inhibition of protein synthesis in growing cells of B. subtilis causes accumulation of ppGpp and pppGpp, which is also in contrast to E. coli. This was shown by isolation and characterization of substances produced in these cells after the addition of chloramphenicol. Other inhibitors of protein synthesis acting at the ribosomal level also cause the accumulation of ppGpp and pppGpp. There is no difference between the action of antibiotics affecting 50-S and/or 30-S ribosomal subunits, since chloramphenicol, tetracycline erythromycin and neomycin cause the accumulation of almost equal amounts of these nucleotides. This apparently resolves the close connection between ppGpp accumulation and the rate of stable RNA synthesis, which was believed to exist also in B. subtilis because of the stringent response observed after amino acid starvation coupled with ppGpp accumulation. Antibiotics which inhibit protein synthesis differently than by affecting the ribosomes (puromycin) or which inhibit RNA (rifampicin) or DNA (nalidixic acid) synthesis do not cause ppGpp accumulation. The accumulation of ppGpp and pppGpp in the presence of charged tRNA provided by chloramphenicol treatment suggests that the signal for the synthesis of unusual nucleotides is an inhibition of the binding of tRNA (charged or uncharged) to the acceptor site of the ribosome. This activates the rel gene product which forms ppGpp and pppGpp from GTP and ATP. Sporulating cells of B. subtilis without chloramphenicol treatment produce besides ppGpp and pppGpp other unusual substances, which are likely to be highly phosphorylated nucleotides contained adenine as base moiety.

Antibiotic Resistance in Neisseria Gonorrhoeae

The hostory epidemiology significance for treatment and future prospects of antibiotic resistance in the gonorrhea bacterium are discussed. Ressistance to sulfonamides developed so rapidly that they were ineffective by the end of World War 2. Since then resistance to penicillin has risen from a point when the minimum inhibitory concentration (MIC) for penicillin ranged from .003-.03 units per ml and 95% cure rates were obtained with a dose of 150000 units to the present when the MIC is typically .5 units per ml in parts of Asia and Africa .1 in U.S.A. and less in northern Europe. Resistance appears to be increasing in places such as Asia where over-the-counter oral antibiotics are available and decreasing in countries such as Greenland where concerted treatment programs using high penicillin doses and probenecid (which prevents excretion of penicillin) have been mounted. Resistance to penicillin is usually associated with resistance to tetracycline erythromycin chloramphenicol fusicid acid rifampicin ethidium bromide and acridine orange. A common genetic mechanism for this multiple drug resistance is being sought. Fortunately spectinomycin or sulfa and trimethoprim therapy is effective against such multiple-drug resistant gonocci.