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This work examined the occurrence characteristics and ecological risks of 31 antibiotics across five classes and seven ARGs in the surface waters of Gaoyou Lake. A total of 27 antibiotics, spanning four classes, were detected in the surface waters of Gaoyou Lake, with an overall concentration ranging from 57.5 to 114 ng/L and an average of 78.8 ng/L. Sulfonamide antibiotics exhibited the highest average concentration at 32.7 ng/L. Spatial analysis revealed that antibiotic concentration levels in the western region of the lake were higher than those in other areas. Similarly, ARGs were most abundant in this area, with sulfonamide ARGs demonstrating a notably higher mean abundance than other ARGs. Correlation analysis revealed strong positive associations between sul1 and several antibiotics, including sulfadimidine, sulfamethoxazole, ciprofloxacin, lincomycin, clindamycin, erythromycin, and intl1 (P < 0.05), with intra-group correlations among sulfonamide ARGs exceeding those between different ARG groups. Ecological risk assessment indicated that erythromycin and sulfamethoxazole presented medium risks, whereas roxithromycin, azithromycin, and lincomycin were associated with low risks to aquatic organisms. The ecological risk proportions across monitoring sites were primarily low (10.6%) and moderate (16.7%), with no high-risk areas identified and 72.7% presenting no risk. The cumulative ecological risk quotient (RQcum) suggested a medium-risk level at all surveyed sites. [ABSTRACT FROM AUTHOR]

Prolonged consumption of animal-derived foods containing high levels of lincomycin (LIN) residues can adversely impact human health. Therefore, it is essential to develop specific antibodies and immunoassay methods for LIN. This study utilized computational chemistry to predict the efficacy of LIN haptens prior to chemical synthesis, with subsequent confirmation obtained through an immunization experiment. A hybridoma cell line named LIN/1B11 was established, which is specific to LIN. The optimized indirect competitive enzyme-linked immunosorbent assay (ic-ELISA) method exhibited high specificity for detecting LIN residues, with an IC50 value of 0.57 ± 0.03 µg/kg. The method effectively detected LIN residues in pork and milk samples, achieving a limit of detection (LOD) ranging from 0.81 to 1.20 µg/kg and a limit of quantification (LOQ) ranging from 2.09 to 2.29 µg/kg, with recovery rates between 81.9% and 108.8%. This study offers a valuable tool for identifying LIN residues in animal-derived food products. Furthermore, the efficient hapten prediction method presented herein improves antibody preparation efficiency and provides a simple method for researchers in screening haptens. [ABSTRACT FROM AUTHOR]

Background: Antibiotic residues come from food of animal origin, such as broiler chicken, have a variety of consequences on human health and increase the likelihood of antibiotic resistance. Lincomycin residue investigations in broiler chicken especially in plasma broiler chicken should be undertaken utilising the validation method analysis. Aim: The purpose of this study is to determine the high-performance liquid chromatography (HPLC) as a validation method for calculating the residual concentration of lincomycin in broiler chicken blood plasma and compare it with the Minimum Inhibitor Concentration (MIC) and Maximum Residue Limits (MRL) standards for lincomycin. Methods: Thirty-five-day-old broiler chickens cobb 700 were weighed and randomly allocated to and separated into control (placebo) and six treatment groups of varying doses and duration. The treatment group's suggested dosage of lincomycin was 50, 100, or 150 mg/kg/day given to 18-day-old chicken, along with drinking water for a week (A group) and two weeks (P group). Lincomycin levels in blood plasma were validated using HPLC. The residual lincomycin concentrations 24 hours and one week after injection were compared to the lincomycin MIC and the Indonesian National Standard of MRL. Result: The validation of lincomycin reveals a linear value in blood plasma with an R2 of 0.9983. Precision and accuracy levels indicate promising results for detecting lincomycin. The retention duration for 100 µg/mL lincomycin was 10.0-10.5 minutes. Lincomycin had LOD and LOQ values of 13.98 and 4.86 µg/mL, respectively. After one week of dosing at 50 and 100 mg/kg dosages, lincomycin residue detection was 0.00, which was below the MRL criterion of [Open Vet J 2024; 14(6.000): 1453-1459]

Background: The TetR family of transcriptional regulators (TFRs), serving as crucial regulators of diverse cellular processes, undergo conformational changes induced by small-molecule ligands, which either inhibit or activate them to modulate target gene expression. Some ligands of TFRs in actinomycetes and their regulatory effects have been identified and studied; however, regulatory mechanisms of the TetR family in the lincomycin-producing Streptomyces lincolnensis remain poorly understood. Results: In this study, we found that AbrT (SLCG_1979), a TetR family regulator, plays a pivotal role in regulating lincomycin production and morphological development in S. lincolnensis. Deletion of abrT gene resulted in increased lincomycin A (Lin-A) production, but delayed mycelium formation and sporulation on solid media. AbrT directly or indirectly repressed the expression of lincomycin biosynthetic (lin) cluster genes and activated that of the morphological developmental genes amfC, whiB, and ftsZ. We demonstrated that AbrT bound to two motifs (5′-CGCGTACTCGTA-3′ and 5′-CGTACGATAGCT-3′) present in the bidirectional promoter between abrT and SLCG_1980 genes. This consequently repressed abrT itself and its adjacent gene SLCG_1980 that encodes an arabinose efflux permease. D-arabinose, not naturally occurring as L-arabinose, was identified as the effector molecule of AbrT, reducing its binding affinity to abrT-SLCG_1980 intergenic region. Furthermore, based on functional analysis of the AbrT homologue in Saccharopolyspora erythraea, we inferred that the TetR family regulator AbrT may play an important role in regulating secondary metabolism in actinomycetes. Conclusions: AbrT functions as a regulator for governing lincomycin production and morphological development of S. lincolnensis. Our findings demonstrated that D-arabinose acts as a ligand of AbrT to mediate the regulation of lincomycin biosynthesis in S. lincolnensis. Our findings provide novel insights into ligand-mediated regulation in antibiotic biosynthesis. [ABSTRACT FROM AUTHOR]

In this study, a liquid chromatographic method was developed for the fast determination of lincomycin, polymyxin and vancomycin in a preservation solution for transplants. A Kinetex EVO C18 (150 × 4.6 mm, 2.6 µm) column was utilized at 45 ◦C. Gradient elution was applied using a mixture of mobile phases A and B, both including 30 mM phosphate buffer at pH 2.0 and acetonitrile, at a ratio of 95:5 (v/v) for A and 50:50 (v/v) for B. A flow rate of 1.0 mL/min, an injection volume of 20 µL and UV detection at 210 nm were used. A degradation study treating the three antibiotics with 0.5 M hydrochloric acid, 0.5 M sodium hydroxide and 3% H2O2 indicated that the developed method was selective toward lincomycin, polymyxin, vancomycin and their degradation products. Other ingredients of the preservation solution, like those from the cell culture medium, did not interfere. The method was validated with good sensitivity, linearity, precision and accuracy. Furthermore, lincomycin, polymyxin and vancomycin were found to be stable in this preservation solution for 4 weeks when stored at −20 ◦C. [ABSTRACT FROM AUTHOR]

The biosynthesis of bioactive secondary metabolites, specifically antibiotics, is of great scientific and economic importance. The control of antibiotic production typically involves different processes and molecular mechanism. Despite numerous efforts to improve antibiotic yields, joint engineering strategies for combining genetic manipulation with fermentation optimization remain finite. Lincomycin A (Lin-A), a lincosamide antibiotic, is industrially fermented by Streptomyces lincolnensis. Herein, the leucine-responsive regulatory protein (Lrp)-type regulator SLCG_4846 was confirmed to directly inhibit the lincomycin biosynthesis, whereas indirectly controlled the transcription of SLCG_2919, the first reported repressor in S. lincolnensis. Inactivation of SLCG_4846 in the high-yield S. lincolnensis LA219X (LA219XΔ4846) increases the Lin-A production and deletion of SLCG_2919 in LA219XΔ4846 exhibits superimposed yield increment. Given the effect of the double deletion on cellular primary metabolism of S. lincolnensis, Plackett-Burman design, steepest ascent and response surface methodologies were utilized and employed to optimize the seed medium of this double mutant in shake flask, and Lin-A yield using optimal seed medium was significantly increased over the control. Above strategies were performed in a 15-L fermenter. The maximal yield of Lin-A in LA219XΔ4846-2919 reached 6.56 g/L at 216 h, 55.1 % higher than that in LA219X at the parental cultivation (4.23 g/L). This study not only showcases the potential of this strategy to boost lincomycin production, but also could empower the development of high-performance actinomycetes for other antibiotics.

Background and Aim: Lincomycin is an antibiotic used in broiler farming and is commonly combined with other substances to achieve synergistic and complementary effects on the antibacterial spectrum and mechanism. We developed a specific high-performance liquid chromatography (HPLC) method to measure lincomycin levels in broiler tissues. This study aimed to determine the lincomycin level in tissues and compare it with the minimum inhibitory concentration (MIC) and maximum residue limit (MRL) of certain pathogenic bacteria. Materials and Methods: Three groups of broiler chickens were involved in the study (n = 20 in each group): A control group without lincomycin treatment and two groups (each further divided into two sub-groups) that received oral lincomycin at a dose of 1 g/10 kg of body weight daily for 7 and 14 consecutive days. Tissue samples were collected from each group 1 day and 1 week after lincomycin administration (ALA). This study validated the development of a technique for analyzing drug level degradation in tissues using HPLC. Descriptive and statistical analyses were performed for drug levels to assess their therapeutic value and safety based on lincomycin MIC of certain pathogenic bacteria and MRL. Results: The method validation resulted in linear regression and coefficient of determination for tissues with r² > 0.99, with a recovery rate of 90%-110%, precision as the coefficient of variation 15%, and specificity with no peak overlap for lincomycin. The limits of detection for the liver and kidney were 0.01 μg/g, 0.05 µg/g, and 0.1 µg/g for the breast muscle and all tissues. Administration of lincomycin for 7 and 14 days resulted in therapeutic value concentrations. Lincomycin levels in the liver and kidney of ALA exceeded the MRL, whereas breast muscles were below the MRL for a week of ALA treatment. Conclusion: Administration of lincomycin for 7 and 14 consecutive days resulted in therapeutic value; however, after a week, most tissues showed high drug concentrations that exceeded the MRL. It is necessary to carefully consider the prolonged therapeutic dose of lincomycin in broilers. Antibiotic therapy must be guided in such a way as to protect the product from harmful residues. [ABSTRACT FROM AUTHOR]

Antibiotics in the aquatic environment are of great concern as novel contaminants. In this study, we investigated the occurrence, distribution, potential sources, and risk assessment of antibiotics in an interconnected river–wetland–lake system. Thirty-three target antibiotics, including sulfonamides (SAs), macrolides (MLs), fluoroquinolones (FQs), tetracyclines (TCs), and chloramphenicol (CLs) belong to five common groups of antibiotics, were tested from water samples collected in the Panlong River, Xinghai Wetland, and Lake Dian (or Dianchi). Mass spectrophotometry was used to detect the target antibiotics, and the water quality parameters were measured in situ. We found four antibiotics, lincomycin (LIN), trimethoprim (TMP), sulfamethoxazole (SMX), and ofloxacin (OFL), with relatively low concentrations at the ng/L level, and detection rates among sample sites ranged from 42.3% to 76.9%, with maximum concentrations of 0.71 ng/L~5.53 ng/L. TMP was not detected in the Panlong River but appeared in the wetlands and Lake Dian. Midstream urban areas of the Panlong River showed the highest pollution among sites. Antibiotic concentrations were positively correlated with total nitrogen (TN) (p < 0.05) and showed some negative correlation with pH, salinity, and DO. According to the risk assessment, antibiotics in water do not pose a threat to human health and aquatic ecosystems, but a potentially harmful combined effect cannot be excluded. Our research offers a geographical summary of the distribution of antibiotics in urban river, wetland, and lake ecosystems in the plateau (PWL), which is important for predicting the distribution characteristics of antibiotics in the plateau water environment and establishing a standardized antibiotic monitoring and management system for the government. [ABSTRACT FROM AUTHOR]

Prolonged consumption of animal-derived foods containing high levels of lincomycin (LIN) residues can adversely impact human health. Therefore, it is essential to develop specific antibodies and immunoassay methods for LIN. This study utilized computational chemistry to predict the efficacy of LIN haptens prior to chemical synthesis, with subsequent confirmation obtained through an immunization experiment. A hybridoma cell line named LIN/1B11 was established, which is specific to LIN. The optimized indirect competitive enzyme-linked immunosorbent assay (ic-ELISA) method exhibited high specificity for detecting LIN residues, with an IC50 value of 0.57 ± 0.03 µg/kg. The method effectively detected LIN residues in pork and milk samples, achieving a limit of detection (LOD) ranging from 0.81 to 1.20 µg/kg and a limit of quantification (LOQ) ranging from 2.09 to 2.29 µg/kg, with recovery rates between 81.9% and 108.8%. This study offers a valuable tool for identifying LIN residues in animal-derived food products. Furthermore, the efficient hapten prediction method presented herein improves antibody preparation efficiency and provides a simple method for researchers in screening haptens.

Background: Antibiotics biosynthesis is usually regulated by the cluster-situated regulatory gene(s) (CSRG(s)), which directly regulate the genes within the corresponding biosynthetic gene cluster (BGC). Previously, we have demonstrated that LmbU functions as a cluster-situated regulator (CSR) of lincomycin. And it has been found that LmbU regulates twenty non-lmb genes through comparative transcriptomic analysis. However, the regulatory mode of CSRs' targets outside the BGC remains unknown. Results: We screened the targets of LmbU in the whole genome of Streptomyces lincolnensis and found fourteen candidate targets, among which, eight targets can bind to LmbU by electrophoretic mobility shift assays (EMSA). Reporter assays in vivo revealed that LmbU repressed the transcription of SLINC_0469 and SLINC_1037 while activating the transcription of SLINC_8097. In addition, disruptions of SLINC_0469, SLINC_1037, and SLINC_8097 promoted the production of lincomycin, and qRT-PCR showed that SLINC_0469, SLINC_1037, and SLINC_8097 inhibited transcription of the lmb genes, indicating that all the three regulators can negatively regulate lincomycin biosynthesis. Conclusions: LmbU can directly regulate genes outside the lmb cluster, and these genes can affect both lincomycin biosynthesis and the transcription of lmb genes. Our results first erected the cascade regulatory circuit of LmbU and regulators outside lmb cluster, which provides the theoretical basis for the functional research of LmbU family proteins. [ABSTRACT FROM AUTHOR]

Over 35 days feeding trial, the effects of lincomycin (LM) and butyrate glycerides (BG) supplementation on the growth performance, blood biochemical changes, immune response, and nutrient absorption related gene expression in broiler chickens were evaluated. A total of 480 one- day-old broiler chicks (Ross 308) were allotted into 6 groups (8 replicates/group with 10 birds/replicate). Experimental groups were arranged as follows; control group (A) fed the basal diet (BD); B, C, and D groups were fed the BD supplemented with 350, 500 and 1000 g BG/ton of feed respectively. While group E was fed the BD with 350 + 500 + 1000 g BG/ton of feed during starter, grower, and finisher periods, respectively, and finally group F which received lincomycin (LM) antibiotic (100 g/ton) in overall periods. Broilers that received BG in group E (birds supplemented with BG at 350 + 500 + 1000 g/ton feed) and LM (F) supplements both gained more body weight and weight growth (P<0.05). Lower feed intake and improved fcr were observed in all the experimental groups that received either BG or lm compared to control birds (P<0.05). Lower serum total cholesterol, triglycerides, and glutamic oxaloacetic transaminase (GOT) (P<0.05) were recorded in the lm or BG supplemented birds compared to the control. Higher immune response represented by enhanced antibody titer against H9N1, and newcastle disease (ND) and lower hepatic malondialdehyde (MDA) was obtained in groups D, E and F (P<0.05) compared to the other groups. Higher gene expression of GSH-Px, Glut 2, PepT1 and FAS was obtained in groups D, E and F (P<0.05) compared to the control. Supplemental BG or LM increased the unsaturated fatty acids (oleic, linoleic and linolenic acids) while lowered the palmitic acid contents in breast muscle (P<0.05) compared to control. In conclusion, supplementing broilers' diets with BG or lincomycin improved their growth performance, immune response and muscle fatty acid profile as well as modulatory role in lipid metabolism. Supplementing starter, grower, and finisher broiler diets with BG at 350 + 500 + 1000 g/ton each may be a useful substitute for lincomycin. [ABSTRACT FROM AUTHOR]

Ribosome‐associated GTPases are conserved enzymes that participate in ribosome biogenesis and ribosome function. In bacteria, recent studies have identified HflX as a ribosome‐associated GTPase that is involved in both ribosome biogenesis and recycling under stress conditions. Plants possess a chloroplastic HflX homolog, but its function remains unknown. Here, we characterized the role of HflX in the plant Arabidopsis thaliana. Our findings show that HflX does not affect normal plant growth, nor does it play an essential role in acclimation to several different stresses, including heat, manganese, cold, and salt stress under the conditions tested. However, we found that HflX is required for plant resistance to chloroplast translational stress mediated by the antibiotic lincomycin. Our results suggest that HflX is a chloroplast ribosome‐associated protein that may play a role in the surveillance of translation. These findings provide new insight into the function of HflX as a ribosome‐associated GTPase in plants and highlight the importance of investigating conserved proteins in different organisms to gain a comprehensive understanding of their biological roles. [ABSTRACT FROM AUTHOR]

The heterogeneous Fenton process is a strategy for overcoming the greatest shortcomings of traditional homogeneous Fenton, i.e. the high generation of ferric hydroxide sludge and effectivity in a limited pH range. In this study, we constructed a heterogeneous Fenton system with natural iron-bearing clay mineral (nontronite) and dimethoxyhydroquinone (DMHQ) to degrade lincomycin (LCM) without the addition of H2O2. The degradation mechanism was derived from the hydroxyl radicals (•OH) produced from the oxygenation of Fe(II) in nontronites, which was reduced by DMHQ. Acidic conditions and low concentrations of LCM were favourable for LCM degradation. When the solution pH increased from 3 to 7, the final LCM removal ratio decreased from 95 to 46%. However, LCM can still be degraded by 46% under neutral conditions and 20% at the LCM concentration of 500 μmol/L. The nontronite has good reusability, and the LCM degradation efficiency in the fourth cycle still exceeded 90% of the original efficiency. The degradation sites of LCM mainly occurred in the methyl thioether moiety and the aliphatic amine group on the pyrrolidine ring, with the final product of CO2. This research presents a new eco-friendly and cost-effective method for the heterogenous Fenton process without external H2O2. HIGHLIGHTS 2,6-DMHQ could reduce structural Fe(III) to form Fe(II) to react with O2 and yield •OH.; LCM could be effectively degraded in the nontronite/2,6-DMHQ reaction system.; The nontronite was efficient with good reusability material.; The clay mineral not only provides iron but also a constrained reaction environment.; The reaction system is efficient, simple, and does not need H2O2 addition.;

ABSTRACT: Lincomycin (LCM) is an antibiotic used to treat severe bacterial infections in livestock and companion animals. In this study, we aimed to investigate the oral bioavailability of LCM with PK data after IV and PO administration and to compare differences in drug residue patterns in eggs. To ensure food safety, an additional study on egg residue was conducted using 3 different commercial LCM drugs. For bioavailability study, laying hens were divided into oral and intravenous (n = 8/group) groups and received single dose (10 mg/kg) of LCM. The limits of quantification for LCM were 0.729 μg/mL and 0.009 mg/kg in plasma and eggs, respectively. The oral group exhibited a significantly lower average serum drug concentration than the IV group, with a bioavailability of 2.6%. Furthermore, the egg residue profiles confirmed reduced systemic drug exposure after oral administration. For the commercial LCM drug egg residue experiment, laying hens were divided into low- and high-dose groups (n = 12/group) for each drug and treated with the recommended dosage and administration method for each respective drug. The eggs were collected and analyzed until 14 d after the last drug treatment. Despite differences in the LCM content and formulation among commercial drugs, all the tested commercial drugs showed average concentrations below the MRL in eggs within approximately 3 d after the last drug treatment. In this study, we have confirmed that LCM has a low oral absorption rate in laying hens, and this was consistent with the findings from the egg residue profiles. Further studies are requested to elucidate the exact reasons for evidently low oral drug absorption in laying hens.

The excessive accumulation of antibiotic residue in animal-derived foods pose a threat to our heath. Therefore, it is necessary to establish a rapid, simple, effective, safe and highly sensitive lincomycin (LIN) residues detection method by high-performance liquid chromatography equipped with ultraviolet. Here, due to the weak UV absorption of LIN, the p-Toluenesulfonyl isocyanate (PTSI, has a strong UV absorption) was binded to the hydroxyl group of LINs by using pre-column derivatization method, improving the UV absorption of LIN. This 9-min-run analytical method detects and quantifies LIN residues with acceptable validation performance parameters in terms of sensitivity, selectivity, linearity, the limit of quantification, accuracy, and precision.Our result showed that the limits of detection and quantification for LIN in samples were 25–40 μg/kg and 40–60 μg/kg, respectively, under the optimized conditions. Furthermore, the LIN recoveries ranged from 72.4 % to 96.7 %; the determination coefficients were 0.9912–0.9996, and the relative standard deviations were 5.6 %-12.7 %. Therefore, the HPLC-UVD method for detecting LIN residues in animal-derived food products has been established.

The antibiotic lincomycin binds to the 23S ribosomal RNA peptidyl transferase loop region to inhibit protein synthesis. However, lincomycin can also stimulate the growth and secondary metabolism of actinomycetes in a concentrationdependent manner. In Streptomyces coelicolor A3(2), lincomycin stimulates the production of the blue-pigmented antibiotic actinorhodin at concentrations below the minimum inhibitory concentration. To better understand the molecular mechanism underlying these concentration-dependent positive effects, this study investigated how the target molecule, the ribosome, undergoes dynamic changes in the presence of lincomycin and explored the ribosome-related factors involved. Lincomycin, at a concentration that stimulates actinorhodin production of S. coelicolor A3(2), could restore temporarily arrested ribosome function by utilizing ribosome-related proteins and translation factors, presumably under the control of the transcription factor WblC protein that confers intrinsic resistance to multiple translation-inhibiting antibiotics, to eventually produce stable and active ribosomes even during the late growth phase. This qualitatively and quantitatively positive ribosome alteration can be advantageous for producing actinorhodin biosynthetic enzymes. A series of gene expression and biochemical analyses revealed that lincomycin at the concentration that induces ribosomal stabilization in S. coelicolor A3(2) could influence the localization of the 20S proteasome-related proteins, resulting in reduced proteasome activity. These findings suggest that the functional analysis of 20S proteasome represents a potential pivotal challenge for understanding the molecular mechanism of ribosome stabilization induced by lincomycin. Therefore, as lincomycin can dynamically alter its target molecule, the ribosome, we discuss the future issues and prospects for an increased understanding of the concentration-dependent properties of antibiotics. [ABSTRACT FROM AUTHOR]

Background: Sodium butyrate (SB) is a short-chain fatty acid and a safe antibiotic alternative. During 35 days, this study compared the impact of coated SB (Butirex C4) and lincomycin (Lincomix) on broiler growth, gut health, and litter hygiene in 1200 one-day-old Ross-308 broiler chicks that were randomly assigned into 5-dietary groups with 5-replications each. Groups divided as follows: T1: Basal diet (control), T2: Basal diet with buffered SB (1 kg/ton starter feed, 0.5 kg/ton grower-finisher feeds), T3: Basal diet with 100 g/ton lincomycin, T4: Basal diet with buffered SB (0.5 kg/ton starter feed, 0.25 kg/ton grower-finisher feeds) + 50 g/ton lincomycin, and T5: Basal diet with buffered SB (1 kg/ton starter feed, 0.5 kg/ton grower-finisher feeds) + 50 g/ton lincomycin. Birds were housed in a semi-closed deep litter house, where feed and water were available ad libitum. Results were statistically analyzed using ANOVA and Tukey's post hoc tests. Results: Combined dietary supplementation with SB and lincomycin (T4 and T5) significantly enhanced body weights, weight gains, feed conversion ratio, and profitability index. Also, carcasses in T4 and T5 exhibited the highest dressing, breast, thigh, and liver yields. T5 revealed the best blood biochemical indices, while T3 showed significantly elevated liver and kidney function indices. T4 and T5 exhibited the highest expression levels of IGF-1 and TLR4 genes, the greatest villi length of the intestinal mucosa, and the lowest levels of litter moisture and nitrogen. Clostridia perfringens type A alpha-toxin gene was confirmed in birds' caeca, with the lowest clostridial counts defined in T4. Conclusions: Replacing half the dose of lincomycin (50 g/ton) with 0.5 or 1 kg/ton coated SB as a dietary supplement mixture showed the most efficient privileges concerning birds' performance and health. [ABSTRACT FROM AUTHOR]

In this study, we evaluated the biotransformation mechanisms of lincomycin (LIN) and three fluoroquinolone antibiotics (FQs), ciprofloxacin (CFX), norfloxacin (NFX), and ofloxacin (OFX), which regularly enter aquatic environments through human activities, by different ammonia-oxidizing microorganisms (AOM). The organisms included a pure culture of the complete ammonia oxidizer (comammox) Nitrospira inopinata, an ammonia oxidizing archaeon (AOA) Nitrososphaera gargensis, and an ammonia-oxidizing bacterium (AOB) Nitrosomonas nitrosa Nm90. The removal of these antibiotics by the pure microbial cultures and the protein-normalized biotransformation rate constants indicated that LIN was significantly co-metabolically biotransformed by AOA and comammox, but not by AOB. CFX and NFX were significantly co-metabolized by AOA and AOB, but not by comammox. None of the tested cultures transformed OFX effectively. Generally, AOA showed the best biotransformation capability for LIN and FQs, followed by comammox and AOB. The transformation products and their related biotransformation mechanisms were also elucidated. i) The AOA performed hydroxylation, S-oxidation, and demethylation of LIN, as well as nitrosation and cleavage of the piperazine moiety of CFX and NFX; ii) the AOB utilized nitrosation to biotransform CFX and NFX; and iii) the comammox carried out hydroxylation, demethylation, and demethylthioation of LIN. Hydroxylamine, an intermediate of ammonia oxidation, chemically reacted with LIN and the selected FQs, with removals exceeding 90%. Collectively, these findings provide important fundamental insights into the roles of different ammonia oxidizers and their intermediates on LIN and FQ biotransformation in nitrifying environments including wastewater treatment systems.

BackgroundLincomycin, a natural antibiotic, is widely used by animal and fishery husbandries to prevent infections and treat diseases. It endangers people’s health when they eat foods containing lincomycin residue, especially the frequent consumption of milk and chicken products containing lincomycin. Hence, it is extremely important to evaluate the content of lincomycin in food samples. However, a direct analysis of lincomycin in milk and chicken is quite difficult because of its very low concentration level and the presence of undesirable matrix effects. Therefore, selective and efficient extraction of lincomycin from complex food samples prior to its quantification is required.ResultsIn this study, lincomycin-imprinted silica nanoparticles were prepared according to boronate affinity-based template-immobilized surface imprinting. Silica nanoparticles and boronic acid ligands 3-fluoro-4-formylphenylboronic acid were used as supporting materials and functional monomers, respectively. The prepared lincomycin-imprinted silica nanoparticles exhibited several significant results, such as good specificity, high binding capacity (19.45 mg/g), fast kinetics (6 min), and low binding pH (pH 5.0) toward lincomycin. The reproducibility of lincomycin-imprinted silica nanoparticles was satisfactory. The lincomycin-imprinted silica nanoparticles could still be reused after seven adsorption–desorption cycles, which indicated high chemical stability. In addition, the recoveries of the proposed method for lincomycin at three spiked levels of analysis in milk and chicken were 93.3–103.3% and 90.0–100.0%, respectively.ConclusionThe prepared lincomycin-imprinted silica nanoparticles are feasible for the recognition of target lincomycin with low concentrations in real food samples such as milk and chicken. Our approach makes sample pre-preparation simple, fast, selective, and efficient.

Antibiotic drug residues can adversely affect the human body. Lincomycin is a common veterinary drug that can form residues in foods of animal origin. However, the detection of trace residue levels of lincomycin residues in real samples is challenging. Here, a simple solid phase extraction (SPE) method was developed for the enrichment of lincomycin from cow milk samples before its detection by high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). The adsorbent used in the SPE was a Cu-based metal-organic framework (Cu-MOF) prepared by the solvothermal synthesis approach. The prepared MOFs were characterized using scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FT-IR), X-ray diffractometry (XRD), differential thermogravimetric analysis (TG-DTA), and N2 adsorption-desorption experiments. The adsorption capacity (adsorption equilibrium, extraction time, pH), and elution solvent parameters were investigated. Under the optimized conditions of the HPLC-MS/MS method, lincomycin was detected in the linear range of 10–200 g/L with a detection limit of 0.013 ng/mL. Commercial milk samples were spiked with lincomycin, and a recovery rate between 92.3% and 97.2% was achieved. Therefore, the current method can be successfully applied for the enrichment and determination of lincomycin from milk samples. [ABSTRACT FROM AUTHOR]

Background and Aims The photoprotective role of foliar anthocyanins has long been ambiguous: exacerbating, being indifferent to or ameliorating the photoinhibition of photosynthesis. The photoinhibitory light spectrum and failure to separate photo-resistance from repair, as well as the different methods used to quantify the photo-susceptibility of the photosystems, could lead to such a discrepancy. Methods We selected two congeneric deciduous shrubs, Prunus cerasifera with anthocyanic leaves and Prunus triloba with green leaves, grown under identical growth conditions in an open field. The photo-susceptibilities of photosystem II (PSII) and photosystem I (PSI) to red light and blue light, in the presence of lincomycin (to block the repair), of exposed leaves were quantified by a non-intrusive P700+ signal from PSI. Leaf absorption, pigments, gas exchange and Chl a fluorescence were also measured. Key Results The content of anthocyanins in red leaves (P. cerasifera) was >13 times greater than that in green leaves (P. triloba). With no difference in maximum quantum efficiency of PSII photochemistry (F v/ F m) and apparent CO2 quantum yield (AQY) in red light, anthocyanic leaves (P. cerasifera) showed some shade-acclimated suites, including lower Chl a / b ratio, lower photosynthesis rate, lower stomatal conductance and lower PSII/PSI ratio (on an arbitrary scale), compared with green leaves (P. triloba). In the absence of repair of PSII, anthocyanic leaves (P. cerasifera) showed a rate coefficient of PSII photoinactivation (k i) that was 1.8 times higher than that of green leaves (P. triloba) under red light, but significantly lower (−18 %) under blue light. PSI of both types of leaves was not photoinactivated under blue or red light. Conclusions In the absence of repair, anthocyanic leaves exhibited an exacerbation of PSII photoinactivation under red light and a mitigation under blue light, which can partially reconcile the existing controversy in terms of the photoprotection by anthocyanins. Overall, the results demonstrate that appropriate methodology applied to test the photoprotection hypothesis of anthocyanins is critical. [ABSTRACT FROM AUTHOR]

The aim of the current study was to investigate the prevalence of Clostridium perfringens (C. perfringens) recovered from animal faeces, as well as to determine the antimicrobial susceptibility of such isolates. A total of 14 (14/100; 14%) C. perfringens isolates were isolated from the 100 analysed samples (twelve recovered from faecal samples collected from pigs and two from veal calves' faecal samples). The preponderant genotype was type A, with all isolates being cpa-positive. The most potent antimicrobial agents against C. perfringens proved to be vancomycin, rifampicin and lincomycin. A strong resistance to tetracycline (71.4%), penicillin (64.2%), erythromycin (42.8%) and enrofloxacin (35.7%) was also observed. To the best of our knowledge, this is the first analysis regarding the prevalence, characterization and antimicrobial susceptibility of C. perfringens in food-producing animals in Romania, adding further evidence for the probable role of animals as a source of resistant C. perfringens strains. [ABSTRACT FROM AUTHOR]

Solvent exchange-induced in situ forming gel (ISG) has emerged as a versatile drug delivery system, particularly for periodontal pocket applications. In this study, we developed lincomycin HCl-loaded ISGs using a 40% borneol-based matrix and N-methyl pyrrolidone (NMP) as a solvent. The physicochemical properties and antimicrobial activities of the ISGs were evaluated. The prepared ISGs exhibited low viscosity and reduced surface tension, allowing for easy injection and spreadability. Gel formation increased the contact angle on agarose gel, while higher lincomycin HCl content decreased water tolerance and facilitated phase separation. The drug-loading influenced solvent exchange and matrix formation, resulting in thinner and inhomogeneous borneol matrices with slower gel formation and lower gel hardness. The lincomycin HCl-loaded borneol-based ISGs demonstrated sustained drug release above the minimum inhibitory concentration (MIC) for 8 days, following Fickian diffusion and fitting well with Higuchi's equation. These formulations exhibited dose-dependent inhibition of Staphylococcus aureus ATCC 25923, Escherichia coli ATCC 8739, and Prophyromonas gingivalis ATCC 33277, and the release of NMP effectively inhibited Candida albicans ATCC 10231. Overall, the 7.5% lincomycin HCl-loaded 40% borneol-based ISGs hold promise as localized drug delivery systems for periodontitis treatment. [ABSTRACT FROM AUTHOR]

Five hundred and sixty broilers were placed into seven groups. The first negative control (A) was fed the baseline diet (BD); the second positive control (B) was fed BD and exposed to clostridium infection; and the third and fourth groups (C, D) were the same as the positive control with 500 and 1000 g/ton of feed, respectively. The fifth group (E) served as a positive control for the addition of lincomycin, whereas the sixth and seventh groups (F, G) received the same designed diet as the E group but supplemented with HA at 500 and 1000 g/ton of feed, respectively. Birds infected with Clostridium perfringens had considerably decreased body weight. However, a dietary combination of HA and lincomycin resulted in a greater improvement in growth. Body weight increased after 35 days, but feed intake dropped, therefore HA and lincomycin supplementation enhanced feed conversion ratio. Supplementing with HA and lincomycin increased crude protein retention. Furthermore, these additions mitigated the detrimental effects of clostridial infection on the gut by reducing degenerative changes in intestinal villi and increasing villi length, particularly at higher HA/lincomycin doses. In conclusion, nutritional supplementation with humic acid and lincomycin improved blood biochemistry, and gut morphology in broilers infected with Clostridium difficile.

Lincomycin industrially produced by Streptomyces lincolnensis can be adopted to treat infections caused by Gram-positive bacteria. SLCG_Lrp, a transcriptional regulator of the Lrp family, was first identified to positively regulate lincomycin biosynthesis. However, the regulatory role of SLCG_Lrp is yet to be elucidated. This study utilized RNA-seq for comparing the transcriptome profile of original-strain LCGL and the ΔSLCGL_Lrp mutant. A total of 244 genes comprising 116 downregulated and 128 upregulated genes were differentially expressed between LCGL and ΔSLCGL_Lrp. An in-depth analysis revealed that SLCG_Lrp promotes nitrate assimilation but inhibits fatty acid metabolism, as well as directly regulates five regulators participating in the modulation of multiple cellular processes. With individual inactivation of those regulatory genes in S. lincolnensis LCGL, we confirmed the FadR transcriptional regulator SLCG_2185 was obviously correlated with lincomycin production and found it to transcriptionally stimulate the lincomycin biosynthetic cluster. Furthermore, SLCG_2185 overexpression in the high-yield S. lincolnensis LA219X promoted lincomycin production by 17.8%, and SLCG_2185 being co-overexpressed with SLCG_Lrp in LA219X increased lincomycin production by 28.1% compared to LA219X. Therefore, this investigation not only provides a direction for further investigations regarding the regulation mechanism of SLCG_Lrp, but also provides a basis for guiding the further improvement of lincomycin levels. [ABSTRACT FROM AUTHOR]

Pharmaceutical plants are an essential source of antibiotics emitted into the aqueous environment. The monitoring of target antibiotics in pharmaceutical plants through various regions is vital to optimize contaminant release. The occurrence, distribution, removal, and ecological risk of 30 kinds of selected antibiotics in 15 pharmaceutical plants in the Pearl River Delta (PRD) were investigated in this study. Lincomycin (LIN) showed the highest concentration (up to 56,258.3 ng/L) in the pharmaceutical plant influents from Zhongshan city. Norfloxacin (NFX) showed a higher detection frequency than other antibiotics. In addition, the spatial distribution of antibiotics in pharmaceutical plants showed significant differences, with higher concentrations of total antibiotics found in pharmaceutical plant influents in Shenzhen City than those of different regions in PRD. The treatment processes adopted by pharmaceutical plants were commonly ineffective in removing antibiotics, with only 26.7% of antibiotics being effectively removed (average removal greater than 70%), while 55.6% of antibiotics had removal rates of below 60%. The anaerobic/anoxic/oxic (AAO)-membrane bioreactor (MBR) combined process exhibited better treatment performance than the single treatment process. Sulfamethoxazole (SMX), ofloxacin (OFL), erythromycin-H2O (ETM-H2O), sulfadiazine (SDZ), sulfamethazine (SMZ), norfloxacin (NFX), and ciprofloxacin (CIP) in pharmaceutical plant effluents posed high or moderate ecological risk and deserve particular attention. [ABSTRACT FROM AUTHOR]

In this study, we describe a case of severe toxicity by lincomycin contamination in feed on a farm housing 1800 rabbit does. The farm used a two-batch system, with parities 24 and 3 d ago, respectively. The rabbits that had consumed the feed developed anorexia 24-48 h later, followed by enteritis-diarrhoea and death. Mortality was >70 % in does, >50 % in 28-day-old kits. None of the 7-day-old kits died from this cause. A total of 125 non-lactating does that had consumed another type of feed from the same supplier were not affected; 10 of them were given the contaminated feed and the same problem occurred. Treatment based on presumptive diagnosis was unsuccessful. Microbiological and histopathological studies identified Clostridium spiroforme, which predominated over coliform bacteria. Toxicology studies requested by the producers verified the existence of 1.6 ppm amoxicillin in the first place; weeks later, further analyses determined 410 ppm lincomycin in doe feed. It also contained the prescribed quantity of 199 ppm tilmicosin. We recommended the stamping-out on the farm.

Mycoplasmoses of cattle and small ruminants, pigs and poultry are widely spread and the infection process is frequently associated with other diseases. Mycoplasma spp. cause inflammatory respiratory diseases, diseases of joints and meninges, keratoconjunctivitis, mastitis and endometritis, abortion and stillbirths. Etiotropic therapy of mycoplasmal infections consists in prescribing antibiotics: enrofloxacin, difloxacin, oxytetracycline, chlortetracycline, doxycycline, tylosin, tilmicosin, tylvalosin, tiamulin, florfenicol, lincomycin, spectinomycin, tulathromycin. The results of studies described in different publications show high sensitivity of Mycoplasma synoviae and Mycoplasma gallisepticum to tetracyclines, tiamulin and tylvalosin. Isolates with increased resistance to tilmicosin are also resistant to tylosin and lincomycin. Treatment of respiratory infections in lambs, the main causative agents of which are Mannheimia haemolytica and Mycoplasma, has been successful with the use of fluoroquinolones, tilmicosin, tulathromycin, chlortetracycline, enrofloxacin, doxycycline, and oxytetracycline. Isolates of Mycoplasma bovis are largely sensitive to oxytetracycline, florfenicol and tulathromycin. Enrofloxacin has a less pronounced therapeutic effect. Tilmicosin and oxytetracycline are effective in the treatment of respiratory diseases of young cattle, associated with Mycoplasma spp. Tulathromycin and tilmicosin have a significant therapeutic effect in the treatment of pneumonia in weaned piglets experimentally infected with Mycoplasma hyopneumoniae. Multiple (course) use of enrofloxacin significantly increases the therapeutic effect. Tilmicosin is effective in the control of other bacterial infections of pigs (pasteurellosis, streptococcosis, hemophilic polyserositis, infectious atrophic rhinitis).The general prophylaxis of mycoplasmal infections is to comply with veterinary and sanitary standards and to implement quarantine measures in the infection outbreak.

For the selective detection of the antibiotic lincomycin, we developed a voltammetric sensor based on a glassy carbon electrode modified with reduced graphene oxide and polyarylenephthalide containing diphenylenethio and diphenyleneoxide fragments in the main chain of the polymer in the 1:1 ratio with lincomycin molecular imprints obtained by phase inversion. Using FTIR spectroscopy, electrochemical impedance spectroscopy, cyclic and differential-pulse voltammetry, the electrochemical and analytical characteristics of the sensor were studied. The detection of lincomycin was carried out by differential pulse voltammetry. The linear concentration range was 2.5·10–7–5·10–4 M with a limit of detection of 6.8·10–8 M. It was shown that the presence of molecular imprints increases the sensitivity of the developed sensor in comparisons with a sensor with non-imprinted polymer by a factor of 3.05.

Erysipelothrix rhusiopathiae is a bacterial pathogen that is the causative agent of erysipelas in a variety of animals, including swine, emus, turkeys, muskox, caribou, moose, and humans. This study aims to investigate the population structure and genomic features of Australian isolates of E. rhusiopathiae in the Australian pig industry and compare them to the broader scope of isolates worldwide. A total of 178 isolates (154 Australian, seven vaccine isolates, six international isolates, and 11 of unknown origin) in this study were screened against an MLST scheme and publicly available reference isolates, identifying 59 new alleles, with isolates separating into two main single locus variant groups. Investigation with BLASTn revealed the presence of the spaA gene in 171 (96%) of the isolates, with three main groups of SpaA protein sequences observed amongst the isolates. Novel SpaA protein sequences, categorised here as group 3 sequences, consisted of two sequence types forming separate clades to groups 1 and 2, with amino acid variants at positions 195 (D/A), 303 (G/E) and 323(P/L). In addition to the newly identified groups, five new variant positions were identified, 124 (S/N), 307 (Q/R), 323 (P/L), 379 (M/I), and 400 (V/I). Resistance screening identified genes related to lincomycin, streptomycin, erythromycin, and tetracycline resistance. Of the 29 isolates carrying these resistance genes, 82% belonged to SpaA group 2-N101S (n = 22) or 2-N101S-I257L (n = 2). In addition, 79% (n = 23) of these 29 isolates belonged to MLST group ST 5. Our results illustrate that Australia appears to have a unique diversity of E. rhusiopathiae isolates in pig production industries within the wider global context of isolates. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the presence and persistence of antibiotics in wastewater of four typical pharmaceutical manufactories in China and receiving water bodies and suggest the removal of antibiotics by the wastewater treatment process. It also evaluated the environmental impact of antibiotic residues through wastewater discharge into receiving water bodies. The results indicated that thirteen antibiotics were detected in wastewater samples with concentrations ranging from 57.03 to 726.79 ng/L. Fluoroquinolones and macrolides were the most abundant antibiotic classes found in wastewater samples, accounting for 42.5% and 38.7% of total antibiotic concentrations, respectively, followed by sulfonamides (16.4%) and tetracyclines (2.4%). Erythromycin-H2O, lincomycin, ofloxacin, and trimethoprim were the most frequently detected antibiotics; among these antibiotics, the concentration of ofloxacin was the highest in most wastewater samples. No significant difference was found in different treatment processes used to remove antibiotics in wastewater samples. More than 50% of antibiotics were not completely removed with a removal efficiency of less than 70%. The concentration of detected antibiotics in the receiving water bodies was an order of magnitude lower than that in the wastewater sample due to dilution. An environmental risk assessment showed that lincomycin and ofloxacin could pose a high risk at the concentrations detected in effluents and a medium risk in their receiving water bodies, highlighting a potential hazard to the health of the aquatic ecosystem. Overall, The investigation was aimed to determine and monitor the concentration of selected antibiotics in 4 typical PMFs and their receiving water bodies, and to study the removal of these substances in PMFs. This study will provide significant data and findings for future studies on antibiotics-related pollution control and management in water bodies. [ABSTRACT FROM AUTHOR]

Non-photochemical quenching (NPQ) has been regarded as a safety valve to dissipate excess absorbed light energy not used for photochemistry. However, there exists no general consensus on the photoprotective role of NPQ. In the present study, we quantified the Photosystem II (PSII) photo-susceptibilities (m pi) in the presence of lincomycin, under red light given to five shade-acclimated tree species grown in the field. Photosynthetic energy partitioning theory was applied to investigate the relationships between m pi and each of the regulatory light-induced NPQ [Y(NPQ)], the quantum yield of the constitutive nonregulatory NPQ [Y(NO)] and the PSII photochemical yield in the light-adapted state [Y(PSII)] under different red irradiances. It was found that in the low to moderate irradiance range (50–800 μmol m–2 s–1) when the fraction of open reaction centers (qP) exceeded 0.4, m pi exhibited no association with Y(NPQ), Y(NO) and Y(PSII) across species. However, when qP < 0.4 (1,500 μmol m–2 s–1), there existed positive relationships between m pi and Y(NPQ) or Y(NO) but a negative relationship between m pi and Y(PSII). It is postulated that both Y(NPQ) and Y(NO) contain protective and damage components and that using only Y(NPQ) or Y(NO) metrics to identify the photo-susceptibility of a species is a risk. It seems that qP regulates the balance of the two components for each of Y(NPQ) and Y(NO). Under strong irradiance, when both protective Y(NPQ) and Y(NO) are saturated/depressed, the forward electron flow [i.e. Y(PSII)] acts as the last defense to resist photoinhibition. [ABSTRACT FROM AUTHOR]

Background: Enterobacter bugandensis is an emerging human pathogen in which multidrug resistant strains have been continuously isolated from various environments. Thus, this organism possesses the potential to pose challenges in human healthcare. However, the mechanisms, especially the efflux pumps, responsible for the multidrug resistance in E. bugandensis remain to be well elucidated. Methods: The Enterobacter strain CMCC(B) 45301 was specifically identified using whole genome sequencing. The specific CMCC(B) 45301 homologues of the TolC dependent efflux-pump genes characterized in Escherichia coli were identified. The tolC deletion mutant in CMCC(B) 45301 was constructed and subjected to susceptibility tests using 26 different antimicrobial agents, along with the wild type strain. The synergistic effects combining the Bacillus crude extract (BCE) and several other TolC-affected compounds against CMCC(B) 45301 were assayed. Results: We reclassified the Enterobacter CMCC(B) 45301 strain from species cloacae to bugandensis, on the basis of its whole genome sequence. We found that the CMCC(B) 45301 TolC, AcrAB, AcrD, AcrEF, MdtABC, EmrAB, and MacAB exhibit high similarity with their respective homologues in E. coli and Enterobacter cloacae. Our results for the susceptibility tests revealed that lacking tolC causes 4- to 256-fold decrease in the minimal inhibitory concentrations of piperacillin, gentamicin, kanamycin, tetracycline, norfloxacin, ciprofloxacin, chloramphenicol, and erythromycin against CMCC (B) 45301. In addition, the inhibition zones formed by cefuroxime, cefoperazone, amikacin, streptomycin, minocycline, doxycycline, levofloxacin, florfenicol, trimethoprim-sulfamethoxazole, azithromycin, lincomycin, and clindamycin for the tolC mutant were larger or more obvious than that for the parent. Our data suggested the important role played by TolC in CMCC(B) 45301 susceptibility to common antibiotic families covering ß-lactam, aminoglycoside, tetracycline, fluoroquinolone, phenicol, folate pathway antagonist, macrolide, and lincosamide. Deletion for tolC also increased the susceptibility of CMCC(B) 45301 to berberine hydrochloride and BCE, two natural product-based agents. Finally, we found that erythromycin, norfloxacin, and ciprofloxacin can potentiate the antibacterial activity of BCE against CMCC(B) 45301. Discussion: The present study elaborated the comprehensive TolC effect on the antimicrobial susceptibility profile in E. bugandensis, which might contribute to the development of more therapeutic options against this nosocomial pathogen. [ABSTRACT FROM AUTHOR]

Five hundred and sixty broilers were placed into seven groups. The first negative control (A) was fed the baseline diet (BD); the second positive control (B) was fed BD and exposed to clostridium infection; and the third and fourth groups (C, D) were the same as the positive control with 500 and 1000 g/ton of feed, respectively. The fifth group (E) served as a positive control for the addition of lincomycin, whereas the sixth and seventh groups (F, G) received the same designed diet as the E group but supplemented with HA at 500 and 1000 g/ton of feed, respectively. Birds infected with Clostridium perfringens had considerably decreased body weight. However, a dietary combination of HA and lincomycin resulted in a greater improvement in growth. Body weight increased after 35 days, but feed intake dropped, therefore HA and lincomycin supplementation enhanced feed conversion ratio. Supplementing with HA and lincomycin increased crude protein retention. Furthermore, these additions mitigated the detrimental effects of clostridial infection on the gut by reducing degenerative changes in intestinal villi and increasing villi length, particularly at higher HA/lincomycin doses. In conclusion, nutritional supplementation with humic acid and lincomycin improved blood biochemistry, and gut morphology in broilers infected with Clostridium difficile. [ABSTRACT FROM AUTHOR]

This study was conducted to evaluate the effects of flavomycin, lincomycin, and zinc bacitracin on body growth, morphometery of immune organs, Newcastle disease virus (NDV) and avian influenza virus (AIV) antibody response, intestinal microflora, and feed efficiency of broilers. Forty-five day-old broiler chickens were randomly divided into five treatments and housed under identical husbandry conditions. Antibiotic-free poultry feed was procured from a commercial feed mill. The antibiotics were mixed in the feed as per the manufacturer's instructions and offered ad libitum to the chickens for the entire study period. The chickens were vaccinated for NDV and AIV. None of the antibiotics adversely affected the development of NDV or AIV hemagglutination inhibition geometric mean titers. Flavomycin and zinc bacitracin did not adversely affect the mean splenic (1.27+0.20 g and 1.21+0.15 g, respectively), thymic (3.42+0.26 g and 3.78+0.48 g, respectively), hepatic (21.78+0.83 g and 23.15+0.37 g, respectively), or bursal (1.55+0.79 g and 1.63+0.21 g, respectively) body weight ratios. However, lincomycin did adversely affect bursal (0.91+0.12 g), but not splenic (1.21+0.23 g), thymic (3.52+0.36 g), or hepatic (23.72+1.78 g) body weight ratios. The total viable bacterial counts per gram of feces before and 120 h after medication were significantly different (p<0.05). Interestingly, the feed efficiency of non-medicated, non-vaccinated chickens was equal to the flavomycin-medicated chickens but better than zinc bacitracin and lincomycinmedicated chickens. Additionally, the non-medicated, non-vaccinated chickens were the most economical to raise. Overall growth-promoting antibiotics did not interfere with the broiler's immunity, altered total intestinal microflora counts, or improved feed efficiency. [ABSTRACT FROM AUTHOR]

Bacterial drug resistance to antibiotics is growing globally at unprecedented levels, and strategies to overcome treatment deficiencies are continuously developing. In our approach, we utilized metal nanoparticles, silver nanoparticles (AgNPs), known for their wide spread and significant anti-bacterial actions, and the high-dose regimen of lincosamide antibiotic, lincomycin, to demonstrate the efficacy of the combined delivery concept in combating the bacterial resistance. The anti-bacterial actions of the AgNPs and the lincomycin as single entities and as part of the combined mixture of the AgNPs–lincomycin showed improved anti-bacterial biological activity in the Bacillus cereus and Proteus mirabilis microorganisms in comparison to the AgNPs and lincomycin alone. The comparison of the anti-biofilm formation tendency, minimum bactericidal concentration (MBC), and minimum inhibitory concentration (MIC) suggested additive effects of the AgNPs and lincomycin combination co-delivery. The AgNPs' MIC at 100 μg/mL and MBC at 100 μg/mL for both Bacillus cereus and Proteus mirabilis, respectively, together with the AgNPs–lincomycin mixture MIC at 100 + 12.5 μg/mL for Bacillus cereus and 50 + 12.5 μg/mL for Proteus mirabilis, confirmed the efficacy of the mixture. The growth curve test showed that the AgNPs required 90 min to kill both bacterial isolates. The freshly prepared and well-characterized AgNPs, important for the antioxidant activity levels of the AgNPs material, showed radical scavenging potential that increased with the increasing concentrations. The DPPH's best activity concentration, 100 μg/mL, which is also the best concentration exhibiting the highest anti-bacterial zone inhibition, was chosen for evaluating the combined effects of the antibiotic, lincomycin, and the AgNPs. Plausible genotoxic effects and the roles of AgNPs were observed through decreased Bla gene expressions in the Bacillus cereus and BlaCTX-M-15 gene expressions in the Proteus mirabilis. [ABSTRACT FROM AUTHOR]

Abstract Purpose The current study aimed to optimize the culture and production parameters of industrial production of lincomycin A by Streptomyces lincolnensis using a statistical approach that could also reduce unwanted by-products. Methods The Plackett-Burman design, steepest ascent method, and response surface design were used to evaluate different factors that affect lincomycin A production. Results Using an optimized S. lincolnensis fermentation medium, lincomycin A production was increased up to 4600 mg/L in shaking flasks, which indicated a 28.3% improvement over previous production in an un-optimized medium (3585 mg/L). Additionally, the concentration of lincomycin B by-product was reduced to 0.8%, which was 82.2% lower than that in the un-optimized medium. Further, quantitative real-time PCR analysis revealed the optimized medium improved lincomycin A production by stimulating key genes in the lincomycin A biosynthesis pathway, as well as an osmotic stress gene. Conclusions Based on the results, the sequential optimization strategy in this study provides powerful means for the enhancement of lincomycin A with less by-product. We found that osmotic stress reduced the concentration of lincomycin B, which could also help reduce fermentation by-product yields in other actinobacteria.

Abstract Background Blue Native polyacrylamide gel electrophoresis (BN PAGE) followed by denaturing PAGE is a widely used, convenient and time efficient method to separate thylakoid complexes and study their composition, abundance, and interactions. Previous analyses unravelled multiple monomeric and dimeric/oligomeric thylakoid complexes but, in certain cases, the separation of complexes was not proper. Particularly, the resolution of super- and megacomplexes, which provides important information on functional interactions, still remained challenging. Results Using a detergent mixture of 1% (w/V) n-dodecyl-β-d-maltoside plus 1% (w/V) digitonin for solubilisation and 4.3–8% gel gradients for separation as methodological improvements in BN PAGE, several large photosystem (PS) I containing bands were detected. According to BN(/BN)/SDS PAGE and mass spectrometry analyses, these PSI bands proved to be PSI-NADH dehydrogenase-like megacomplexes more discernible in maize bundle sheath thylakoids, and PSI complexes with different light-harvesting complex (LHC) complements (PSI-LHCII, PSI-LHCII*) more abundant in mesophyll thylakoids of lincomycin treated maize. For quantitative determination of the complexes and their comparison across taxa and physiological conditions, sample volumes applicable to the gel, correct baseline determination of the densitograms, evaluation methods to resolve complexes running together, calculation of their absolute/relative amounts and distribution among their different forms are proposed. Conclusions Here we report our experience in Blue/Clear-Native polyacrylamide gel electrophoretic separation of thylakoid complexes, their identification, quantitative determination and comparison in different samples. The applied conditions represent a powerful methodology for the analysis of thylakoid mega- and supercomplexes.

Abstract Background Enterococcus cecorum (EC) is one of the main reasons for skeletal disease in meat type chickens. Intervention strategies are still rare and focus mainly on early antibiotic treatment of the disease, although there are no data available concerning the effectivity of this procedure. The present study aimed to investigate the effectivity of early lincomycin-spectinomycin treatment during the first week of life after EC-infection. Furthermore, the impact of lincomycin-spectinomycin treatment and EC infection on the development of cecal microbiota was investigated. Methods A total of 383 day-old broiler chicks were randomly assigned to four groups (non-infected and non-treated, non-infected and treated, EC-infected and non-treated, and EC-infected and treated). The EC-infected groups were inoculated orally with an EC suspension at the day of arrival and at study day 3. The treatment groups were treated with lincomycin-spectinomycin via the drinking water for six consecutive days, starting two hours after the first inoculation. Necropsy of 20 chickens per group was performed at study days 7, 14, 21, and 42. Bacteriological examination via culture and real-time PCR was performed to detect EC in different extraintestinal organs. Cecal samples of nine chickens per group and necropsy day were analyzed to characterize the composition of the cecal microbiota. Results No clinical signs or pathologic lesions were found at necropsy, and EC was not detected in extraintestinal organs of the EC-infected and treated birds. Lincomycin-spectinomycin promoted the growth of the bacterial genus Escherichia/Shigella and reduced the amount of potentially beneficial Lactobacillus spp. in the ceca regardless of EC-infection. Unexpectedly, the highest abundances of the genus Enterococcus were found directly after ending antibiotic treatment in both treatment groups, suggesting the growth of resistant enterococcal species. EC was not detected among the most abundant members of the genus Enterococcus. Oral EC-infection at the first day of life did not influence the development of cecal microbiota in the present study. Conclusions Lincomycin-spectinomycin treatment during the first week of life can prevent the EC-associated disease in broiler type chickens and has a direct impact on the development of the cecal microbiota. The low abundance of EC in the ceca of infected chickens underlines the pathogenic nature of the disease-causing EC strains. Further research on alternative prevention and intervention strategies is needed with regard to current efforts on reducing the use of antibiotics in livestock animals.

A high-performance self-driven photoelectrochemical (PEC) platform was designed based on 0D N-doped Ti3C2 quantum dots/oxygen vacancies (OVs) engineered 2D BiOBr nanosheets (N-doped Ti3C2 QDs/BiOBr) nanocomposites for sensitive detection of lincomycin (Lin). The synergistic interplay between 0D N-doped Ti3C2 QDs and 2D BiOBr can generate the fascinating interface of chemical/electronic coupling to further boost the PEC activity, including efficient charge transfer, extended the light absorption and increased carrier density. Experimental results demonstrated that the PEC response of the prepared OV-riched N-doped Ti3C2 QDs/BiOBr van der Waals (vdW) heterostructures were 9-folds stronger than that of OV-deficient BiOBr. On the basis of the such excellent PEC performance, an ultrasensitive self-driven PEC aptasensor was developed with the assistance of Lin aptamer. The proposed sensor exhibited a wide linear response (1.0 × 10−14 mol/L ∼ 1.0 × 10−8 mol/L), a low detection limit (3.57 × 10−15 mol/L, S/N = 3), excellent selectivity and good reproducibility, which provided a promising tool to detect Lin in real samples. This work not only offered a versatile protocol for a wide variety of PEC detection, but also paved the way for the development of more efficient PEC biosensor.

The overuse of antibiotics has led to the emergence of resistant bacteria. A good alternative is silver nanoparticles, which have antibacterial activity against Gram-negative and Gram-positive bacteria, including multidrug-resistant strains. Their combination with already known antibiotics has a synergistic effect. In this work, we studied the synthesis of conjugates of silver nanoparticles with two antibiotics, lincomycin and cefazolin. Albumin and glutathione were used as spacer shells with functional groups. The physicochemical properties of the obtained conjugates, their cytotoxicity and synergism of antimicrobial activity were studied. The 50% antimicrobial activity of the obtained samples was shown, which allows them to be recommended for use as topical drug preparations. [ABSTRACT FROM AUTHOR]

Lincomycin is a broad-spectrum antimicrobial acting against Gram-positive bacteria, widely used in veterinary medicine. In fish, there are only limited in vitro data, thus requiring the design of effective therapeutic protocols for their use in aquatic organisms. In this context, the objective was to evaluate the clinical safety of lincomycin treatment, administered orally in tilapia, through hematological, biochemical and somatic index evaluation. A total of 136 tilapia (±100g) were randomly distributed in 17 tanks (100L of water, n=8) to constitute the following treatments: T0 (control group, not treated with lincomycin); T1, T2, T3 (treated with 10, 20 and 40mg/kg-1 of lincomycin b.w., respectively) and T4 physiological standard (reference values). Eight animals were sampled per treatment in 4 periods: 2, 4 and 8 days post-treatment (DPT), and a group that was treated for 8 days with the drug and then treated only with commercial feed until the 12th day (recovery period). Tilapia treated with lincomycin had no difference in the hematological and leukocyte evaluation, in the hepatic, renal and splenic somatic index. However, they presented a transient increase in the values of ALT, AST, cholesterol, triglycerides and creatinine, which returned to normal levels after the period of recovery (12DPT). Furthermore, an increase in total protein, albumin and globulin levels was observed in treated animals. It is concluded that although there were some transient changes during the experiment, lincomycin has a good clinical safety margin at doses of 10, 20 and 40mg/Kg-1 b.w. for Nile tilapia. [ABSTRACT FROM AUTHOR]

Bovine mastitis is a common bacterial infection that causes inflammation of the mammary gland in dairy cattle. Staphylococcus is one of the most predominant and significant pathogens known to cause mastitis. Thus, this study was designed to isolate and assess the prevalence of Staphylococcus strains in dairy cattle with clinical mastitis in Region IV-A, Philippines. Baird Parker agar (BPA) supplemented with 5% egg yolk tellurite emulsion was used as selective media to differentiate coagulase-positive S. aureus and coagulase-negative staphylococcus (CNS). The isolated pathogens were phenotypically and genetically characterized for further identification. Surprisingly, out of 85 isolates, only 56.5% belong to the genus Staphylococcus and 43.5% were non-staphylococcus strains despite the use of a staphylococcus-specific selective medium. The overall most prevalent species among the isolates were S. chromogenes with an isolation rate of 21.2%. The antimicrobial resistance profiles of the isolated bacterial pathogens were also done. Several staphylococcal isolates exhibited resistance to multiple antibiotics. S. aureus showed hyper-resistance to three out of seven antibiotics -- specifically streptomycin, clindamycin, and lincomycin. Surprisingly, most of the non-staphylococcal isolates exhibited hyper-resistance to multiple antibiotics. Proteus mirabilis, P. penneri, and Providencia stuartii showed almost 100% resistance and hyper-resistance to all antimicrobials tested except amoxicillin. These findings suggest that the detection of diverse species of mastitis-causing microorganisms is an important concern for the dairy sector, as different pathogens might represent different hazards and require distinct treatments, particularly on the type of antibiotics used to treat the infection. The erroneous choice of antimicrobial could unnecessarily expose the udder microbial flora to antimicrobials, thereby inadvertently promoting the emergence of multidrug-resistant pathogens that poses a serious threat to both animal and human health. Extreme antibiotic resistance detected in strains present in mastitic dairy cattle also raises a substantial public health concern, particularly when it comes to the consumption of food and food products, such as milk. [ABSTRACT FROM AUTHOR]

Simple Summary: Morganella morganii is a motile, non-spore-forming, rod-shaped facultative an-aerobic gram-negative bacterium found in the intestines of people, the oral cavity of animals, and the environment. Reptiles, guinea pigs, rabbits, jaguars, elephant seals, broiler chickens, piglets, and dolphins have all been documented to have M. morganii infection. Medicinal leeches are used in surgical and non-surgical manners. Treatment of long-term and chronic pain syndrome induced by degenerative diseases in a non-surgical method. For the first time in Iran, our investigation discovered M. morganii-infected Hirudo medicinalis. Infection with M. morganii caused a significant death and morbidity rate (70%) and severe clinical abnormalities. Medicinal leeches (Hirudo medicinalis) are used in surgical and non-surgical manners. Morganella morganii is an opportunistic and zoonotic pathogenic bacterium causing serious clinical complications. In this study, we isolated, discovered and characterized M. morganii-infected H. medicinalis. We detected and identified M. morganii in all inflamed and swollen Hirudo medicinalis samples. The 16S rRNA sequence of the isolates confirmed all strains of M. morganii. All strains were sensitive to Ceftriaxone, Ceftiofur, Danofloxacin, Ciprofloxacin, Enrofloxacin, Oxytetracycline, and Meropenem and were resistant to Erythromycin, Amoxicillin, Ampicillin, Cefazolin, Colistin, Penicillin G, and Lincomycin. This pathogenic bacterium is a zoonotic pathogen, and monitoring the prevalence rate of this bacteria is strongly necessary for leeches used in human medical treatment and care. Finally, all infected leeches were treated successfully in this case report study. [ABSTRACT FROM AUTHOR]

Staphylococcus equorum strain KM1031 is resistant to chloramphenicol, erythromycin and lincomycin. To shed light on the genetic factors underlying these antibiotic resistances, we determined the global gene expression profile of S. equorum KM1031 using RNA sequencing. During chloramphenicol, erythromycin and lincomycin treatment, 8.3% (183/2,336), 16.0% (354/2,336), and 2.9% (63/2,336) of S. equorum KM1031 genes exhibited significant differences in expression, respectively. These three antibiotics upregulated genes related to efflux and downregulated genes related to transporters. Antibiotic treatment also upregulated osmoprotectant-related genes involved in salt tolerance. To identify specific genes functionally related to antibiotic resistance, we compared the genome of strain KM1031 with those of three S. equorum strains that are sensitive to these three antibiotics. We identified three genes of particular interest: an antibiotic biosynthesis monooxygenase gene (abm, AWC34_RS01805) related to chloramphenicol resistance, an antibiotic ABC transporter ATP-binding protein gene (msr, AWC34_RS11115) related to erythromycin resistance, and a lincosamide nucleotydyltransferase gene (lnuA, AWC34_RS13300) related to lincomycin resistance. These genes were upregulated in response to the corresponding antibiotic; in particular, msr was upregulated more than fourfold by erythromycin treatment. Finally, the results of RNA sequencing were validated by quantitative real-time PCR. This transcriptomic analysis provides genetic evidence regarding antibiotic stress responses of S. equorum strain KM1031. [ABSTRACT FROM AUTHOR]

Background: Antimicrobial resistance (AMR) is a global public health emergency driven by the indiscriminate use of antimicrobial agents in humans and animals. Antimicrobial consumption surveillance guides its containment efforts. In this study, we estimated, for the first time, veterinary consumption of Critically Important Antimicrobials with Highest Priority (CIA-HtP) for Pakistan. Methods: The study used an export/import database which provided imports data collected from the Pakistan Customs Authority. We investigated imports of 7 CIA-HtP and various poultry feed additives/growth promoters (FAs/GPs) identified from a survey of 10 poultry and dairy farms in Punjab province in Pakistan and a previously published study, over a three-year period of 2017–2019. Antimicrobial consumption was estimated in mg/kg of country's animal biomass. Findings: Imports, in tonnes, for these 7 CIA-HtP were for the years 2017–19: tylosin 240.84, enrofloxacin 235.14, colistin 219.73, tilmicosin 97.32, spiramycin 5.79, norfloxacin 5.55, ceftiofur 1.02 for a total 805.39 tonnes. The corresponding antimicrobial consumption was 10.05 mg/kg of animal biomass. The poultry FAs/GPs contained: zinc bacitracin, enramycin, bacitracin methylene disalicylate, tylosin, tiamulin, colistin, lincomycin, streptomycin, flavophospholipol, tilmicosin, and penicillin with a total antimicrobial chemical compound (ACC) import volume of 577.18 tonnes for the years 2017–2019; and an estimated consumption of 96.53 mg/kg of poultry biomass. Interpretation: These antimicrobials were a mix of macrolides, quinolones, polymyxins and cephalosporins, among which are some also on the Watch or Reserve list by the WHO, indicating the need for stewardship and to conserve essential antimicrobials to contain AMR. The finding that a yearly average of 192.39 tonnes of the ACC imported were FAs/GPs further highlight the need for stronger regulation and enforcement. [ABSTRACT FROM AUTHOR]

Chronic endometritis (CE) is an infectious disease of the uterine lining, which is characterized by endometrial stromal plasmacyte (ESPC) infiltration. CE is often seen in infertile women with a history of repeated implantation failure (RIF) following an in vitro fertilization-embryo transfer program, recurrent pregnancy loss, and unknown etiology. Oral antibiotic agents, such as doxycycline, metronidazole, ciprofloxacin, azithromycin, and moxifloxacin, have been prescribed and are effective in the treatment of CE. Multi-drug resistance (MDR), however, is an emerging issue, as in other medical fields. We report six cases of persistent MDR-CE in infertile women who were resistant to all the aforementioned antibiotic agents. The bacterial genera and microbial communities unique to persistent MDR-CE were not identified in their vaginal secretions and/or endometrial fluid. Oral lincomycin administration (14 days, 1500 mg/day) was effective in the eradication of ESPCs in these women. In the embryo transfer cycles following histopathologic confirmation of cure (elimination of ESPCs) of persistent MDR-CE, three out of them had a successful live birth. [ABSTRACT FROM AUTHOR]