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Streptococcus agalactiae serotype distribution and its antibiotic susceptibility affect disease prevention strategies, but the serotype distribution varies among patient groups. The objectives of this study were to establish the group B Streptococcus (GBS) serotype distribution in patients from Egypt and to assess antibiotic sensitivity of invasive GBS isolates. A total of 490 patients participated in this multicenter study; 160 had urinary tract infection, 115 complained of diabetic foot ulcers, 125 men had genital tract infections, and 30 women females had genital tract infections. Others had bronchopneumonia, otitis media, synovitis, or meningitis. Serotyping of the isolated GBS was performed at the CDC in the United States. Antibiotic sensitivity patterns were determined using the disk diffusion method. In men, the most common serotypes were II, III, and V, whereas types Ia, II, III, and V were isolated from women. Macrolides (erythromycin) resistance occurred in 4.1% of the isolates; 10.2% were resistant to both clindamycin and inducible resistance of macrolides, lincomycin, and streptogramin; 17.3% were resistant to quinolones; and 95.9% were resistant to tetracyclines. GBS primarily infected the urinary tract, skin, soft tissue, and genital tract in both genders. Isolates were sensitive to beta-lactam drugs, vancomycin, and linezolid; 14.0% were resistant to macrolides with or without clindamycin. Only 6.0% of the strains were sensitive to tetracyclines. Although GBS causes invasive infections in Egyptian adults, it rarely causes neonatal meningitis or sepsis. Future studies should determine whether GBS isolates are transmitted sexually, by performing a follow-up study of the partner of the infected patient.

Background Listeria monocytogenes is one of the deadliest foodborne pathogens. The bacterium can tolerate severe environments through biofilm formation and antimicrobial resistance. This study aimed to investigate the antimicrobial susceptibility, resistance genes, virulence, and molecular epidemiology about Listeria from meat processing environments. Methods This study evaluated the antibiotic resistance and virulence of Listeria isolates from slaughtering and processing plants. All isolates were subjected to antimicrobial susceptibility testing using a standard microbroth dilution method. The harboring of resistant genes was identified by polymerase chain reaction. The multilocus sequence typing was used to determine the subtyping of the isolates and characterize possible routes of contamination from meat processing environments. The virulence of different STs of L. monocytogenes isolates was evaluated using a Caco-2 cell invasion assay. Results A total of 59 Listeria isolates were identified from 320 samples, including 37 L. monocytogenes isolates (62.71%). This study evaluated the virulence of L. monocytogenes and the antibiotic resistance of Listeria isolates from slaughtering and processing plants. The susceptibility of these 59 isolates against 8 antibiotics was analyzed, and the resistance levels to ceftazidime, ciprofloxacin, and lincomycin were as high as 98.31% (L. m 37; L. innocua 7; L. welshimeri 14), 96.61% (L. m 36; L. innocua 7; L. welshimeri 14), and 93.22% (L. m 35; L. innocua 7; L. welshimeri 13), respectively. More than 90% of the isolates were resistant to three to six antibiotics, indicating that Listeria isolated from meat processing environments had high antimicrobial resistance. Up to 60% of the isolates harbored the tetracycline-resistance genes tetA and tetM. The frequency of ermA, ermB, ermC, and aac(6′)-Ib was 16.95, 13.56, 15.25, and 6.78%, respectively. Notably, the resistant phenotype and genotype did not match exactly, suggesting that the mechanisms of antibiotic resistance of these isolates were likely related to the processing environment. Multilocus sequence typing (MLST) revealed that 59 Listeria isolates were grouped into 10 sequence types (STs). The dominant L. monocytogenes STs were ST5, ST9, and ST121 in the slaughtering and processing plant of Jiangsu province. Moreover, ST5 subtypes exhibited high invasion in Caco-2 cells compared with ST9 and ST121 cells. Conclusion The dominant L. monocytogenes ST5 persisted in the slaughtering and processing plant and had high antimicrobial resistance and invasion characteristics, illustrating a potential risk in food safety and human health.

A total of 410 milk samples were collected from different ruminant species as the following ; cows (n = 110), buffaloes (n = 87) ) , does (n=108) ) and ewes (n=105) from different Egyptian farms .The results revealed that prominence of L.monocytogenes in the examined milk samples are 1.72 % at apparently healthy cow , 2.77 % in subclinical mastitic cow and in apparently healthy goat is 1.38 % and this has a public health importance. The recovered isolates identified biochemically as L.monocytogenes confirmed phenotypically by positive hemolytic reaction and motility , followed by molecular confirmation using specific primer sequences of 16s rRNA at 1200 bp followed with sequencing and accession on genbank . Antibiogram of the isolated L. monocytogenes are demonstrated resistance to tetracyclines, lincomycin, streptomycin, cefotaxime, Trimethoprime sulfamethoxazole, florphenicols, and clindamycin, while adherence assay for test glass tube polystyrene microtiter plates conclude that L. monocytogenes was able to form a strong biofilm.

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.

E. coli is one of the most important pathogenic bacteria in poultry industry. It causes high economic losses, high morbidity and mortality rates due to collibacillosis. Moreover, it is multidrug resistant bacteria. In the last few years, scientists directed their efforts to the use of essential oils which have antimicrobial actions by inhibition of some virulence properties such as biofilm formation and quorum sensing. In this study, out of 150 examined samples, 139 were found to be bacteriologically positive for G-ve bacilli (92.7%) and 84 E. coli isolates (60.4%) were recovered from broilers suffering from pericarditis. Twenty random recovered isolates were selected for antimicrobial susceptibility test. All isolates were completely resistant to amoxicillin, gentamicin, lincomycin and florfenicol and 90% resistant to trimethoprim- sulfamethoxazole, kanamycin, ciprofloxacin and doxycycline while sensitivity to amoxicillin+clavulanic acid and cefotaxime was 40% and 20% respectively. We screened 15 randomly selected MDR isolates by CR assay for detection of biofilm formation at which CR positive isolates represent 80%. Cinnamon and clove oils showed antimicrobial effect and cause down regulation in both biofilm gene (sfa) and quorum sensing gene (luxS).

The control of Mycoplasma hyorhinis infection relies mainly on antimicrobial therapy. However, the antibiotic susceptibility testing of the bacteria is usually not performed before applying the treatment, and thus therapeutic failures are not uncommon. In the case of M. hyorhinis, several antibiotic-resistance-related single nucleotide polymorphisms (SNPs) are known but assays for their detection have not been described yet. The aims of the present study were to investigate macrolide- and lincomycin-resistance-related SNPs in Hungarian M. hyorhinis isolates and to develop mismatch amplification mutation assays (MAMA) to detect the identified resistance markers. Minimal inhibitory concentrations (MIC) of different drugs and whole genome sequences of 37 M. hyorhinis isolates were used to find the resistance-related mutations. One MAMA assay was designed to detect the mutation of the 23S rRNA gene at nucleotide position 2058 (Escherichia coli numbering). For further evaluation, the assay was challenged with 17 additional isolates with available MIC data and 15 DNA samples from clinical specimens. The genotypes of the samples were in line with the MIC test results. The developed assay supports the practice of targeted antibiotic usage; hence it may indirectly reduce some bacterial resistance-related public health concerns.

Edwardsiella tarda is a common fish pathogen, causing significant septicemic diseases in fish. This study was carried out to investigate prevalence of E. tarda among Tilapia zilli at EL manzla lake, Dakahlia governorate and characterize the isolates phenotypically and genotypically in addition to detection of multi-drug resistance genes (B-lactames genes and plasmid-mediated quinolone resistant genes by PCR assay. Therefore, (100) samples of Tilapia zilli collected from different localities. Fish samples were subjected to clinical and post-mortem examination then bacteriological examination from liver, kidney and spleen. The suspected isolates were characterized by cultural and morphological characters, some conventional biochemical tests and API 20E system then by PCR assay. Eighteen % isolates were characterized as E. tarda. Furthermore, detection of antimicrobial resistance genes by PCR, the recovered isolates harbored blaSHV and blaOXA-1 with a prevalence of 50% and 25%, respectively with no detection of aac (6′)-Ib-cr and qepA genes in examined isolates. The results of antibiotics sensitivity showed resistance to Nalidixic acid, Lincomycin, Amoxicillin and Norfloxacin and most of isolate were found to be sensitive to Florfenicol and Neomycin.55.6% of recovered isolates showed resistance to three antibiotic classes and 27.7% of recovered isolates showed resistance to four antibiotic classes and considered as MDR. The emergence of MDR-strains represents a threat-alarm and PCR is very rapid method for identification of E. tarda isolates which may be helpful in control of Edwardsiellosis.

Salmonella spp. is a major foodborne pathogen that is distributed among most pork production chains worldwide. This study aimed to investigate the dynamic changes in Salmonella spp. along the pig breeding process monthly from April 2018 to March 2019 in a pig farm in Shanghai, China, and identify the potential critical control points during the production. In total, 239 Salmonella spp. isolates were obtained from 1389 samples, in which Salmonella were detected from 26.3% (222/843) of fecal samples, 7.1% (17/240) of feed samples, and 0.0% (0/306) of both water and insect samples. Seven different serotypes were identified, with the predominant serotype being Salmonella Derby (21.8%), followed by Salmonella Typhimurium (18.8%), Salmonella Rissen (16.3%), Salmonella Mbandaka (12.6%), and Salmonella 1,4,[5],12:i:- (11.8%). Most probable number (MPN) analysis revealed that the load of Salmonella spp. gradually increased along the pig production chain, while the highest number of Salmonella spp. isolates was at the fattening stage (MPN value, 11-15 MPN/g). The pulsed-field gel electrophoresis showed that both Salmonella Typhimurium and Salmonella Derby isolates were grouped to six clusters. The antimicrobial resistance analyzed demonstrated that 80.0% of the isolates were of multidrug resistance and resistant to sulfamethoxazole (84.5%), lincomycin (89.4%), ampicillin (96.9%), oxytetracycline (93.8%), and tetracycline (95.1%). We further evaluated the Salmonella spp. Resistance to quaternary ammonium compounds (QACs) showed an increasing trend along with the testing period indicating that the use of QACs could induce the resistance of Salmonella spp. to QACs. Our study confirmed the dynamic changes in Salmonella spp. over time and space in this pig farm and identified feed and the fattening house as the key points for the prevention and control of Salmonella spp. contamination.

Aims: Fish pathogenic Lactococcus garvieae serotype II has been isolated from cultured fish species in Japan. This study aimed to investigate the molecular mechanisms of lincomycin (LCM)-resistant ...

A bacteriological study of milk samples from cows with clinical forms of mastitis from four livestock farms of different districts of the Leningrad regione, were conducted. During the bacteriological study of milk from cows with mastitis, we isolated 68 cultures of different types of microorganisms, which indicates the diversity of the microbial “paysage”. Among the isolated microflora, the dominant ones were staphylococci (including hemolytic), microorganisms of the genus Bacillus (including hemolytic), Enterobacteria (Escherichia coli, Klebsiella). Streptococci (including hemolytic), Pseudomonas aeruginosa were isolated. The sensitivity of the isolated cultures of staphylococci to antibacterial drugs was determined by the disco-diffuse method. In order to select effective treatment agents in the dominant species of microorganisms, sensitivity to antibacterial drugs of different groups (aminoglycosides, amphenicols, macrolides, polypeptides, tetracyclines, fluoroquinolones, cephalosporins, and others) was studied. When determining the sensitivity, the best results were shown by antibiotics from the group of aminoglycosides (gentamicin), macrolides (azithromycin), amphenicols (levomycetin), fluoroquinolones (ciprofloxacin, enrofloxacin), cephalosporins (ceftiofur) – more than 50% of the studied cultures were sensitive to them. Lincomycin showed the worst results – all 9 studied cultures of staphylococci were resistant to this drug. When using antibiotics for the purpose of treatment in each individual case, it is necessary to check the sensitivity of crops isolated in the farm to antibacterial drugs. Unsystematic treatment with antibiotics is not only ineffective, but also causes significant damage, as antibiotic resistance develops.

Objective: A study is carried out to investigate the prevalence of mastitis caused by Streptococcus agalactiae and Streptococcus dysgalactiae in cows and buffaloes, their antibiotics susceptibility, minimum inhibitory concentrations (MIC), and molecular investigation of some virulence genes. Samples: A total of 288 milk samples gathered from 72 mastitic animals from households and small-scale dairy farms in Egypt, were analyzed. Procedures: Isolation and identification of S. agalactiae and S. dysgalactiae were performed using conventional techniques. The identified isolates were examined for antimicrobial resistance by disk diffusion assay, MIC by broth microdilution method as well as virulence genes by PCR. Results: Forty-five out of 72 animals show the clinical signs of mastitis. Microbiological evaluation of 288 mastitis milk samples displayed 190 (65.72%) streptococci strains composing of 60% S. agalactiae and 40% S. dysgalactiae strains. The antibiotic susceptibility tests revealed that S. agalactiae strains were resistant to trimethoprim (100%), followed by tetracycline and minocycline (37.7%). Moreover, S. dysgalactiae strains were highly resistant to lincomycin, tetracycline (87.52 each), followed by trimethoprim (81.6) and minocycline (75%). Additionally, the highest MIC with the widest range (1 to ≥128 μg/mL) were observed to trimethoprim for S. agalactiae and to erythromycin and lincomycin for S. dysgalactiae. In contrast, the lowest MIC was detected to penicillin, amoxicillin, cefquinome, and erythromycin for S. agalactiae and to penicillin, amoxicillin, cephapirin, cefquinome, and rifaximin for S. dysgalactiae. The cylE gene is displayed in 6 (60%) S. agalactiae strains, whereas the mig gene is found in 4 (40%) S. dysgalactiae strains.

Avian pathogenic Escherichia coli (APEC) causes a variety of bacterial infectious diseases known as avian colibacillosis leading to significant economic losses in the poultry industry worldwide and restricting the development of the poultry industry. The development of efflux pumps is one important bacterial antibiotic resistance mechanism. Efflux pumps are capable of extruding a wide range of antibiotics out of the cytoplasm of some bacterial species, including β-lactams, polymyxins, tetracyclines, fluoroquinolones, aminoglycosides, novobiocin, nalidixic acid, and fosfomycin. In the present study, we constructed the mcbR mutant and the mcbR-overexpressing strain of E. coli strain APECX40 and performed antimicrobial susceptibility testing, antibacterial activity assays, real-time reverse transcription PCR, and electrophoretic mobility shift assays (EMSA) to investigate the molecular regulatory mechanism of McbR on the genes encoding efflux pumps. Our results showed that McbR positively regulates cell susceptibility to 12 antibiotics, including clindamycin, lincomycin, cefotaxime, cefalexin, doxycycline, tetracycline, gentamicin, kanamycin, norfloxacin, ofloxacin, erythromycin, and rifampicin by activating the transcription of acrAB, acrD, emrD, and mdtD (P

Introduction: Pneumonia is an acute infection of lung majorly caused by Streptoneumococcal bacteria or other microbes which present cough with phlegm (mucus), fever and other clinical symptoms. This mucus produced are easily polymerize with other similar natural product like snail mucin when taken which serves as a natural antimicrobial immune booster for enhanced or synergistic response against causative agent in the presence of antibiotics. This work was carried out to determine the combined effect of snail mucin as animal sourced natural product antimicrobial agent with lincomycin against different strains of Streptococcus pneumoniae as alternative treatment option for this respiratory tract infection “pneumonia” which has been a global challenge especially in the tropical Africa. Methods: Separate solution each of the two agent was prepared in sterile normal saline to get a different concentration of the agents, each solution contained twice the MIC of the agent. The agents were then combined in different ratios for interaction effect by adopting the standard continuous variation method and further diluted using two-fold serially dilutions and evaluated against the test organisms using both agar diffusion and dilution method respectively. Results: The result of FIC index was calculated showed greater synergy in the equal ratio (50:50) combination against all the strains of tested organisms. Also, better performance at the combinations ratios of 60:40 and 40:60 of mucin and lincomycin respectively emerged. Conclusion: This synergistic effect has shown an improved natural product immuno-antimicrobial chemotherapy for alternative treatment option of such acute infection in the absent orthodox medicine.

Activating the genetic potential of Streptomyces strains to produce secondary metabolites can improve the production of useful biologically active compounds and facilitate the discovery of novel biologically active compounds. In this study, we found that Streptomyces lividans carrying the R440H mutation in rpoB, encoding the RNA polymerase beta subunit, grown in the presence of lincomycin at concentrations below the minimum inhibitory concentration (MIC) produced abundant amounts of actinorhodin and certain cryptic secondary metabolites despite culture conditions that restrict their production by the wild-type strain. The results indicate that lincomycin at concentrations below the MIC may strongly potentiate secondary metabolite production by Streptomyces strains carrying a specific rpoB mutation. In this study, we report an interesting phenomenon induced by combining the positive effects of certain rpoB mutations and concentration-dependent responses to lincomycin on secondary metabolism in S. lividans 66 and discuss the mechanisms and their applicability in exploring cryptic secondary metabolite production in streptomycetes.

In the present study, Salmonella spp. was successfully isolated from Asian clam Corbicula fluminea by using Xylose Lysine Deoxycholate (XLD) selective agar. A total of 200 bacterial colonies from live Asian clams were isolated and subjected to antimicrobial sensitivity test by using disc diffusion method. A total of 18 antibiotics was applied in the present study, namely oxolinic acid, nalidixic acid, erythromycin, tetracycline, doxycycline, oleandomycin, oxytetracycline, spiramycin, ampicillin, kanamycin, fosfomycin, florfenicol, lincomycin, novobiocin, chloramphenicol, amoxycillin, flumequine and sulphamethoxazole. The findings of the present study showed that total antibiotic sensitive case for Salmonella spp. isolated from C. fluminea sample was 50% or 1800 cases. This was followed by antibiotic resistance case 45% or 1620 cases and intermediary antibiotic sensitive case (5% or 180 cases). Based on the results of the present study, tetracycline, doxycycline, oxytetracycline and flumequine showed the highest inhibition of isolated Salmonella spp. The multiple antibiotic resistance (MAR) index was 0.36, indicating the sampled clams were highly exposed to the tested antibiotics.

Annotation. S. aureus is a leading cause of nosocomial infections in health care facilities. The aim of the study was to determine the effectiveness of the use of staphylococcal bacteriophage, phytopreparation “Chlorophyllipt”, of the drug “Protargol”, compared with antimicrobial chemotherapeutic drugs (ACD) against isolates of Staphylococcus aureus in vitro. Used clinical strains of S. aureus, isolated from 20 patients, aged 19 to 25 years. The susceptibility of microorganisms to ACD was determined on the MPA medium by disk-diffusion method. Staphylococcal bacteriophage sensitivity scores were evaluated by drainage lysis of bacterial indicator culture and negative phage colonies. Anti-staphylococcal activity of phytopreparation and protargol solution was determined by diffusion in agar with the isolates tested. Statistical data processing was performed using Microsoft Excel 2013. In determining the susceptibility of S. aureus isolates to ACD, 30% of penicillin-sensitive strains were detected. Amoxicillin sensitivity was 25% of strains. The rate of detected sensitivity of microorganisms to amoxiclav was 45% of strains. Sensitivity to cephalosporins I-II generation amounted to 75% cephalexin, cefazolin, cefuroxime — 90%. For cephalosporins of the third generation — from 70% to 95%; to macrolides: to clarithromycin — 80%, to erythromycin, azithromycin — 50%, 55% respectively. High sensitivity was reported for lincomycin — 80%. The studied strains showed absolute sensitivity to amikacin (100%). 95% strains were sensitive to gentamicin. Not exceed 60–65% sensitivity to tetracyclines and fluoroquinolones. All bacterial isolates were sensitive to bacteriophage. High antimicrobial activity in up to chlorophyllipt was detected in up to 8 test strains. 19 strains have had low-sensitivity to protargol. The results obtained indicate the feasibility of bacteriophages in the medical practice and the continuation of microbiological studies with the study of antimicrobial activity of herbal drugs.

Papillomatous digital dermatitis (PDD) is a foot disease causing lameness in dairy cattle. It is regarded as a polymicrobial infection, although its etiology is not fully understood. PDD is treated by the topical or systemic administration of antibiotics such as lincomycin (LCM); however, the milk of the cows cannot be marketed during the treatment and withdrawal period due to the residual antibiotics in milk. Allyl isothiocyanate (AITC), an extract of Wasabia japonica (known as wasabi or Japanese horseradish) widely employed as a food additive, can be used as an alternative antimicrobial agent that overcomes this problem. We previously showed that AITC is as effective as LCM in PDD treatment. Here, using the samples obtained in the previous clinical study, we analyzed changes in the bacterial population in the PDD-associated microbiota after AITC treatment and compared those with that following LCM treatment by 16S ribosomal RNA (rRNA)-based amplicon analysis. Both treatments induced major changes in the bacterial population, and Treponema species, which have been regarded as the major causative agents of PDD, were efficiently eliminated by both agents. However, the AITC-treated samples exhibited higher diversity compared with pretreatment samples, but this trend was not observed for LCM treatment, probably reflecting different antibacterial activities of the two agents. Importantly, this analysis detected population changes before morphological changes in PDD lesions (clinical signs of healing) became evident, indicating that 16S rRNA-based amplicon analysis represents an efficient strategy for analyzing and monitoring the treatment efficiency of PDD as well as other polymicrobial diseases.

For the first time the poly-resistant strains of Gram-negative microorganisms were studied for the sensitivity to combined simultaneous and sequential influence of metabolic complexes of Lactobacillus rhamnosus GG and Saccharomyces boulardii, obtained by the author’s method without using the growth media, with antibiotics. The synergic activity of antibacterial preparations and metabolic complexes of L. rhamnosus GG and S. boulardii were studied using modified disk-diffusive method of Kirby-Bauer. During the sequential method of testing (at first the microorganisms were incubated with structural components and metabolites, then their sensitivity to the antibacterial preparations was determined), we observed increase in the diameters of the zones of growth inhibition of Pseudomonas aeruginosa PR to the typical antibiotics (gentamicin, amіcyl, ciprofloxacin, сefotaxime) and non-typical (lincomycin, levomycetin) depending on the tested combinations. Acinetobacter baumannii PR exhibited lower susceptibility: growth inhibition was seen for the combination with ciprofloxacin, сefotaxime, levomycetin. Susceptibility of Lelliottia amnigena (Enterobacter amnigenus) PR increased to levofloxacin, lincomycin. The zones of growth inhibition of Klebsiella pneumoniae PR increased to gentamicin, amіcyl, tetracycline, сeftriaxone. Maximum efficiency was determined during sequential combination of antibiotics with separate metabolic complexes of L. rhamnosus and S. boulardii, and also their combination (to 15.2, 20.2 and 15.4 mm respectively) compared with their simultaneous use (to 12.2, 15.2 and 13.0 mm respectively) for all the tested poly-resistant pathogens, regardless of the mechanism of action of antibacterial preparation. Metabolic complexes of L. rhamnosus GG and S. boulardii, due to increase in the susceptibility of microorganisms, can decrease the therapeutic concentration of antibiotic, slow the probability of the development of resistance of microorganisms, and are therefore promising candidates for developing “accompanying medications” to antibiotics and antimicrobial preparations of new generation.

One hundred and sixty clinically diseased broiler local chickens collected from 22 different farms belonging to Qalubia, Dakahlia and Gharbia governorates were subjected to bacteriological examination and molecular characterization. Clinical Signs were chronic respiratory disease with respiratory manifestations,lameness, loss or reduction in egg production.Bacteriological examination showed that 18.18% of the isolates were Mycoplasma positive and showed growth in pleuropneumonia-like organism (PPLO) agar plates, with fried egg appearance when examined by stereoscopic microscope. Mycoplasma colonies were tested for antimicrobial sensitivity tests against 12 antimicrobial antibiotics and showed higher sensitivity to nitrofurantoin, gentamicin, norfloxacin, ciprofloxacin and neomycin. Intermediate sensitivity were recorded to ceftriaxone and cefotaxime and antibiotic resistance were recorded to tetracyclines, lincomycin, chloramphenicole and sulphamethoxasine. Identification of the bacterial strains of the isolates were conducted by multiplex PCR by using two primer pairs for Mycoplasma synoviae (vlhA) and Mycoplasma gallisepticum (mgc2). The amplicons expected size were 396 bp, and 300 bp for vlhA and mgc2 respectively. Only13 out of 22 farms were positive, representing 59.09 %.Moreover, the incidence rate of Mycoplasma synoviae (vlhA) and Mycoplasma gallisepticum (mgc2) were 22.72% and 13.63% respectively and 22.72% of the inspected farms showed positive results for both Mycoplasma strains.

Purpose Methicillin-resistant S. aureus (MRSA) belonging to clonal complex 15 (CC15-MRSA) is rare among clinical isolates with few reports from retail camel meat and human patients. This study investigated the genetic relatedness of CC15-MRSA isolated for the first time from patients in Kuwait hospitals. Methods Antibiotic susceptibility was tested by the disk diffusion method. Minimum inhibitory concentration was determined using Etest strips. Molecular typing was performed using spa tying, multilocus sequence tying and DNA microarray. Results Of 1327 MRSA isolates, 42 (3.1%) were identified as CC15-MRSA. The 42 isolates belonged to sequence type ST1535-harbored SCCmec type V and spa types t084 (36 isolates), t346 (3 isolates) and one of t114, t228 and t7583. All 42 isolates were resistant to gentamicin, kanamycin, fusidic acid and cadmium acetate; 38 isolates were resistant to tetracycline. The isolates harbored aacA-aphD and fusC that codes for gentamicin and fusidic acid resistance, respectively. Tet(K) was present in the tetracycline-resistant isolates. In addition, the 42 isolates carried inu(A) (lincosamide nucleotidyltransferase) that confers resistance to lincomycin and clindamycin although phenotypically susceptible to these antibiotics. The isolates belonged to accessory gene regulator type II and capsular polysaccharide group 8 but lacked genes for Staphylococcus enterotoxins, toxic shock syndrome toxin, collagen-binding adhesins and Panton-V alentine leukocidin. Conclusion This study revealed the emergence and transmission of a previously rare MRSA clone among human patients in Kuwait hospitals and highlights the increasing infiltration of rare MRSA into the human population.

A total of 82 C. perfringensisolates (41%) were recovered from 200 samples collected from 100 turkeys (20 apparently healthy, 40 clinically diseased and 40 freshly dead), 4-6 weeks old. The clinical signs of diseased birds were sudden mortality, depression, ruffled feathers, diarrhea, dehydration, emaciation and decrease in feed consumption with increase in water consumption. While, postmortem findings were consistent with necrotic enteritis (NE), the small intestine was severely affected. Small and demarcated lesions were found in the duodenal loop, hepatitis and cholecystitis were also observed. Unopened intestines were gas-filled and enlarged with thin wall. The intestinal contents were dark due to necrotic material. The opened intestines showed necrotic lesions of varying severity of the mucosa. Isolation and biochemical identification of C.perfringenswere done.Five C.Perfringens field isolates were analyzed by PCR assay to determine the presence of some toxin genes.In all tested isolates, the Cpa gene (alpha toxin) was detected (100%) confirming the isolates were C.perfringens. While, Cpb (beta toxin) gene was detected in two samples (40%). But the Etx gene (epsilon toxin) was not detected in any isolate (0%). NetB gene was detected in two isolates (40%). Antimicrobial susceptibility of 40 C.perfringens field isolates recovered from turkeys revealed that C.perfringens isolates were sensitive to Ampicillin (85%), Amoxicillin (85%), Penicillin (82.5%), Florfenicol (72.5%), Enrofloxacin (67.5%), Vancomycin (65%), Bacitracin (60%), Oxytetracyclin (32.5%), Lincomycin (22.5%) and Clindamycin (15%).These five C. perfringens isolates were also screened by PCR which detected the presence of tetracycline resistance gene tet(K) in three isolates (60%) and Lincomycin resistance gene lin(B) in three isolates (60%).

Forty eight clinically diseased broiler chickens from different (n=18) farms from Beni Suef and El-Fayoum Governorates were subjected to euthanasia and post mortem examination. Lesions include airsaculitis, pericarditis and perihepatitis. Bacteriological examination showed that 22.9% of isolates were E. coli positive. Serogrouping of isolates revealed O125, O112, O91, O157, O115 and O25 % of each serogroups with an incidence rate of 18.2%, 9.1%, 9.1%, 9.1%, 9.1%, and 9.1%, respectively and four strains were untyped. Antimicrobial sensitivity tests against 17 antimicrobials showed that the most common resistance patterns were against penicillin, lincomycin, oxytetracycline, clindamycin, amoxycillin and erythromycin followed by nalidix acid and trimethoprim. On the other hand, the most potent antimicrobials were colistin sulphate, gentamycin, doxycycline and ceftriaxone followed by enrofloxacin, ciprofloxacin, norfloxacin, chloramphenicol and lastly ampicillin. PCR showed that all isolates had B-lactam resistant gene (blaTEM) and tetracycline resistance gene A (tetA) but only 18 % have quinolones resistance gene A (qnrA).

Antibiotic-associated diarrhea (AAD) is a self-limiting disease mediated by antibiotic therapy. In clinical practice, several types of probiotics are used in treating AAD, but minimal research has been done on Bacteroides-based microecologics. Our aim was to evaluate the therapeutic effects of Bacteroidetes uniformis FGDLZ48B1, B. intestinalis FJSWX61K18, Bifidobacterium adolescentis FHNFQ48M5, and B. bifidum FGZ30MM3 and their mixture on AAD in mice. The lincomycin hydrochloride-induced AAD models were gavaged with a single strain or a probiotic mixture for a short period to assess the changes in colonic histopathology and cytokine concentrations, intestinal epithelial permeability and integrity, short-chain fatty acids (SCFAs), and the diversity of intestinal microbiota. Our data indicated that both the sole use of Bacteroides and the combination of Bacteroides and Bifidobacterium beneficially weakened systemic inflammation, increased the recovery rate of tissue structures, increased the concentrations of SCFAs, and restored the gut microbiota. Moreover, the probiotic mixture was more effective than the single strain. Specifically, B. uniformis FGDLZ48B1 combined with the B. adolescentis FHNFQ48M5 group was more effective in alleviating the pathological features of the colon, downregulating the concentrations of interleukin (IL)-6, and upregulating the expression of occludin. In summary, our research suggests that administration of a mixture of B. uniformis FGDLZ48B1 and B. adolescentis FHNFQ48M5 is an effective approach for treating AAD.

Acholeplasma (A.) laidlawii is an opportunistic pathogen with the ability to disseminate resistance determinants to antibiotics, however, its resistance to macrolides has been less studied. The aim of the present study was to characterize the mechanisms responsible for the resistance to macrolides, tiamulin and lincomycin found in a strain of A. laidlawii isolated from a pig with pneumonia. MICs of erythromycin, 15- and 16-membered macrolides, tiamulin and lincomycin were determined by microdilution method with and without reserpine, an inhibitor of ABC efflux pumps and regions of the genome were sequenced. Reserpine only decreased lincomycin MIC but it did not change the MICs of macrolides and tiamulin. The analysis of the DNA sequence of 23S rRNA showed nucleotide substitutions at eight different positions, although none of them were at positions previously related to macrolide resistance. Five mutations were found in the L22 protein, one of them at the stop codon. In addition, two mutations were found in the amino acid sequence of L4. The combination of multiple mutations in the ribosomal proteins L22 and L4 together with substitutions in 23S rRNA DNA sequence was associated with the resistance to macrolides, the pleuromutilin and lincomycin in the studied A. laidlawii strain.

Rhodothermus marinus is a halophilic extreme thermophile, with potential as a model organism for studies of the structural basis of antibiotic resistance. In order to facilitate genetic studies of this organism, we have surveyed the antibiotic sensitivity spectrum of R. marinus and identified spontaneous antibiotic-resistant mutants. R. marinus is naturally insensitive to aminoglycosides, aminocylitols and tuberactinomycins that target the 30S ribosomal subunit, but is sensitive to all 50S ribosomal subunit-targeting antibiotics examined, including macrolides, lincosamides, streptogramin B, chloramphenicol, and thiostrepton. It is also sensitive to kirromycin and fusidic acid, which target protein synthesis factors. It is sensitive to rifampicin (RNA polymerase inhibitor) and to the fluoroquinolones ofloxacin and ciprofloxacin (DNA gyrase inhibitors), but insensitive to nalidixic acid. Drug-resistant mutants were identified using rifampicin, thiostrepton, erythromycin, spiramycin, tylosin, lincomycin, and chloramphenicol. The majority of these were found to have mutations that are similar or identical to those previously found in other species, while several novel mutations were identified. This study provides potential selectable markers for genetic manipulations and demonstrates the feasibility of using R. marinus as a model system for studies of ribosome and RNA polymerase structure, function, and evolution.

Macrolides and lincosamides are first choice bacteriostatic antibiotics used in veterinary dermatology. The main antibiotics in these classes are erythromycin, lincomycin, clindamycin and tylosin. They are well absorbed if given orally and are able to penetrate well into infected skin. Their spectrum of action comprises bacteria commonly associated with skin infections, including staphylococci. Their main disadvantages are the rapid development of bacterial resistance and occasional gastroenteric upset, most often seen with erythromycin. More recently developed macrolides, such as azithromycin and clarithomycin, are bactericidal, have a larger spectrum of action, a longer endurance, less resistance and may be given once a day instead of two or three times daily.

In natural environments, antibiotics are important means of interspecies competition. At subinhibitory concentrations, they act as cues or signals inducing antibiotic production; however, our knowledge of well-documented antibiotic-based sensing systems is limited. Here, for the soil actinobacterium Streptomyces lincolnensis, we describe a fundamentally new ribosome-mediated signaling cascade that accelerates the onset of lincomycin production in response to an external ribosome-targeting antibiotic to synchronize antibiotic production within the population. The entire cascade is encoded in the lincomycin biosynthetic gene cluster (BGC) and consists of three lincomycin resistance proteins in addition to the transcriptional regulator LmbU: a lincomycin transporter (LmrA), a 23S rRNA methyltransferase (LmrB), both of which confer high resistance, and an ATP-binding cassette family F (ABCF) ATPase, LmrC, which confers only moderate resistance but is essential for antibiotic-induced signal transduction. Specifically, antibiotic sensing occurs via ribosome-mediated attenuation, which activates LmrC production in response to lincosamide, streptogramin A, or pleuromutilin antibiotics. Then, ATPase activity of the ribosome-associated LmrC triggers the transcription of lmbU and consequently the expression of lincomycin BGC. Finally, the production of LmrC is downregulated by LmrA and LmrB, which reduces the amount of ribosome-bound antibiotic and thus fine-tunes the cascade. We propose that analogous ABCF-mediated signaling systems are relatively common because many ribosome-targeting antibiotic BGCs encode an ABCF protein accompanied by additional resistance protein(s) and transcriptional regulators. Moreover, we revealed that three of the eight coproduced ABCF proteins of S. lincolnensis are clindamycin responsive, suggesting that the ABCF-mediated antibiotic signaling may be a widely utilized tool for chemical communication. IMPORTANCE Resistance proteins are perceived as mechanisms protecting bacteria from the inhibitory effect of their produced antibiotics or antibiotics from competitors. Here, we report that antibiotic resistance proteins regulate lincomycin biosynthesis in response to subinhibitory concentrations of antibiotics. In particular, we show the dual character of the ABCF ATPase LmrC, which confers antibiotic resistance and simultaneously transduces a signal from ribosome-bound antibiotics to gene expression, where the 5' untranslated sequence upstream of its encoding gene functions as a primary antibiotic sensor. ABCF-mediated antibiotic signaling can in principle function not only in the induction of antibiotic biosynthesis but also in selective gene expression in response to any small molecules targeting the 50S ribosomal subunit, including clinically important antibiotics, to mediate intercellular antibiotic signaling and stress response induction. Moreover, the resistance-regulatory function of LmrC presented here for the first time unifies functionally inconsistent ABCF family members involving antibiotic resistance proteins and translational regulators.

Gram-negative Aeromonas bacteria is known to contaminate aquaculture products and retains the ability to infect wide range of host including fishes, shrimps and humans. This study is designed to evaluate the presence of Aeromonas in healthy loaches (Misgurnus anguillicaudatus) collected from the markets in Hainan and Guangdong provinces of China. Based on the molecular sequencing and phylogenetic analysis with single 16S rRNA and concatenated genes (gyrA and ropD), 104 isolates were identified as Aeromonas species followed by further classification to A. veronii (83.65%), A. jandaei (9.62%), A. hydrophila (3.85%) and A. allosaccharophila (2.88%). More than half of the isolates displayed hemolytic activity of 87.5% and were able to form moderate biofilm (78.26%). Fourteen antibiotics from ten representative classes were screened that demonstrated complete resistance to ampicillin, 89.4% and 68.3% to lincomycin and nalidixic acid. Moreover, a notable detection and prevalence was found in screening of ten virulence-related and nine resistance genes. To our knowledge, it is the first report of its kind demonstrating potential threat of the commercial loaches carrying Aeromonas to human health. These findings will assist professionals working in clinical settings to optimize their prescription accordingly and researchers to access the impacts of Aeromonas resistance on human health.ImportanceThis study demonstrates high infection rate of loaches by Aeromonas spp. in Hainan and Guangdong provinces of China.The most prevalent species was Aeromonas veronii.Most of the isolates displayed hemolytic activity and formed moderate biofilm.Multiple virulence genes, resistance genes and multi-antibiotic resistance were detected.Aeromonads risks should be considered in loach industry.

Many Mycoplasma species are involved in caprine and ovine pneumonia all over the world causing serious economic losses. These species have been reported as a cause of pneumonia, mastitis, arthritis, conjunctivitis and genital infection. The detection of Mycoplasma species in the respiratory system of sheep and goat was the objective of the present study. So, a total of 400 samples (250 from sheep and 150 from goat) were examined bacteriologically, biochemically; PCR, and by sequencing; in addition to the antibiotic susceptibility profiles screening. Only 13 isolates could be identified as Mycoplasma species. One of these sequences was submitted to the Genbank taking the accession number MK910041; Mycoplasma species 'ovine/caprine serogroup 11'. Only 7 isolates were weak biofilm producer and the other 6 isolates were non biofilm producers; 8 isolates were positive for catalase test and 5 were negative. H2S production was recorded in 10 isolates; hemolysis was detected in only 6 isolates. In addition, the minimum inhibitory concentrations (MICs) for seven antimicrobial agents, including danofloxacin, tulathromycin, tylosin, streptomycin, lincomycin, florfenicol and oxytetracycline were determined. All the isolates (100%) were sensitive to tulathromycin and tylosin, streptomycin and oxytetracycline, 38.5% of them were sensitive to danofloxacin and 69.2% were sensitive to florfenicol while 69.2% of isolates were resistant to lincomycin. As all the isolates were recovered from apparently healthy as well as clinically diseased animals and identified as untyped Mycoplasma species, So, more investigations will be done to full identify these isolates and discover their roles in infection.

Background: Increasing evidence suggests that antibiotic administration causes gut injury, nutrient digestion, immune regulation, and colonization resistance against pathogens due to the disruption of gut microbiota. However, the time-course effects of therapeutic antibiotics on alterations of gut microbes and short-chain fatty acid in young swine are still unknown. In this study, twenty piglets were assigned into two groups and fed commercial diets with or without lincomycin in the first week for a 28-day trial period. Results: Data showed that one-week lincomycin exposure did reduce the body weight on day 14 (p = 0.0450) and 28 (p = 0.0362). The alpha-diversity notably reduced after one-week lincomycin treatment, then gradually raised and reached the control group level in the second week on cessation of lincomycin exposure, indicated by the variation of Sobs, Chao, Shannon, and ACE index (p < 0.05). Beta-diversity analysis revealed that the distinct microbial cluster existed persistently for the whole trial period between two groups (p < 0.001). The relative abundance of most microbes including fiber-degrading (e.g., Agathobacter, Coprococcus, etc.), beneficial (e.g., Lactobacillus, Mitsuokella, etc.), or pathogenic bacteria (e.g., Terrisporobacter, Lachnoclostridium, etc.) decreased and the concentration of short-chain fatty acids also diminished in the feces of one-week lincomycin-administrated young swine (LDA score > 3). After the lincomycin administration stopped, the state of gut dysbiosis gradually recovered and formed new gut-microbe homeostasis distinct from microbial homeostasis of young pigs unexposed to lincomycin. The increased presence of potential pathogens, such as Terrisporobacter, Negativibacillus, Escherichia-Shigella, etc. and decreased beneficial bacteria such as Lactobacillus, Agathobacter were observed in new homeostasis reshaped by short-lincomycin administration (LDA score > 3 or p < 0.05), adversely affecting gut development and health of young pigs. Conclusion: Collectively, these results suggested that severe disruption of the commensal microbiota occurred after short-term lincomycin exposure or termination of lincomycin exposure in young swine. Our study depicts the change rule of gut microbiota in young animals under the condition of short-term lincomycin treatment, providing basic data for evaluating the harmful impact on gut microbe of young animals.

The objective of this study was to explore the therapeutic effects of berberine on necrotic enteritis (NE) in broilers caused by Clostridium perfringens. A total of 240 1-day-old Arbor Acres chicks were divided into four groups, as negative controls (NC), positive controls (PC), berberine- (BER-) treated, or lincomycin- (LMY-) treated groups. Broilers were challenged with C. perfringens at 15-21 days of age, followed by BER or LMY supplied in drinking water for 7 days. Experimental results showed that C. perfringens infection significantly decreased growth performance and increased intestinal necrosis index and the number of C. perfringens present to 6.45 Log10CFU/g ( P < 0.001 ). Proinflammatory cytokines in the ileum were significantly increased, but the expression of ileal tight junction proteins occludin and claudin-1 was significantly reduced. Both BER and LMY ameliorated some of these observations. Compared with the PC group, the number of C. perfringens in the cecum was significantly decreased following treatment ( P < 0.001 ), and growth performance and small intestine morphology were similar to those of the NC group ( P > 0.05 ). IL-1β, IL-6, and TNF-α levels as well as occludin and claudin-1 expression were also significantly improved ( P < 0.05 ). BER has the potential to replace antibiotics for NE caused by C. perfringens.

Pasteurella multocida, an important gram-negative pathogen that mainly inhibits the upper respiratory tracts of domestic and wild animals such as chicken, duck, cattle and pig, which can cause cholera fowl, haemorrhagic septicaemia and infectious pneumonia. Currently, the prevalence and infection of P. multocida is still one of the most serious threats to the poultry industry in China, but studies on its characteristics are still insufficient. Here, this study was conducted to isolate and identify P. multocida in infected ducks and determined the leading serotypes and epidemiology of the diseases this pathogen causes. Results indicated that all the isolates were positive for KMT1 gene and the PCR amplified products were approximately 460 bp, demonstrating that these strains were all P. multocida. Moreover, all the isolated strains were identified as capsular type A and lipopolysaccharide type L1. Virulence factor identification results revealed that all strains possessed genes related to pili, adhesin, iron metabolism and uptake. In contrast, toxin coding gene (toxA) and sialidase encodes genes (nan B and nan H) were not detected in any isolates. The drug susceptibility results indicated that all the isolates were resistant to Lincomycin, Chloramphenicol, Clindamycin and Oxacillin but were sensitive to Ceftriaxone and Cefalotin. The animal experiments were also performed to further determine the pathogenicity of these isolated strains. Animal experiment revealed that the liver, kidney, and heart of infected ducks were swollen and had bleeding spots. We also observed hepatocyte hypertrophy, hepatic sinus congestion and single-cell infiltration in infected ducks through H&E staining. In summary, this study demonstrated that all the isolated strains belong to capsular A and lipopolysaccharide type L1 P. multocida, but their virulence factors, drug resistance and pathogenicity were different.

Swine dysentery (SD) is an important endemic disease of pigs throughout the world. The most common aetiological agent is the anaerobic intestinal spirochaeteBrachyspira hyodysenteriae.The related spirochaeteBrachyspira pilosicolicauses a milder form of colitis. We report the first isolation ofB. hyodysenteriaeandB. pilosicolifrom a pig farm in Hong Kong. Faecal samples containing mucus or fresh blood were collected from the ground where finisher pigs had just been loaded into a truck for transport to the abattoir. The samples were subjected to selective anaerobic culture and PCR forB. hyodysenteriaeandB. pilosicoli, and two isolates of both species were obtained. TheB. hyodysenteriaeisolates showed clinical resistance to tylosin and lincomycin, whilst theB. pilosicoliisolates were resistant to tylosin and showed intermediate susceptibility to lincomycin. TheB. hyodysenteriaeisolates were subjected to multilocus sequence typing and a single previously undescribed sequence type (ST250) was identified. Disease was not recorded in other pigs on the farm, but it may have been masked by the use of antimicrobials. Further work is required to examine the distribution of these two pathogens in this and other farms in Hong Kong and in adjoining mainland China.

The purpose of this study was to analyze the antibiotic resistance and genetic diversity of 27 enterococci (Enterococcus faecium, Enterococcus hirae, Enterococcus durans, and Enterococcus casseliflavus) isolated from wild bird species. Resistance to lincomycin was most common, followed by erythromycin, ciprofloxacin, tetracyclines, high level of aminoglycoside, and β-lactam antibiotics. No vancomycin- and chloramphenicol-resistant isolates were identified. The antibiotic resistance was linked to the tet(M), tet(L), erm(A), erm(B), msr(A/B), pbp5, ant(6)-Ia, and aph(3')-IIIa genes. Tn916/Tn1545-like transposons were detected. The high-level resistance to gentamicin was associated with the presence of gene aph(2″)-Id. All 18 E. faecium isolates were divided into 16 pulsotypes and 17 sequence types (STs), among which 7 STs were newly assigned (ST1266-ST1272). A majority of E. faecium isolates possess multilocus sequence typing profiles belonging to clonal complex 17 (CC17), the major epidemic lineage responsible for nosocomial infections. Two ST17 and newly described ST1267 and ST1271 (an SLV and DLV of ST17, respectively) of E. faecium isolates carried the type 1 allele of the housekeeping gene purK detected in hospital-related strains. Our results indicated that wild birds could be a source of resistant E. faecium isolates, belonging to CC17 and may represent a hazard to human health by transmission of these isolates.

Turkey coryza is a major respiratory disease caused by Bordetella avium (B. avium). It occurs in all ages of turkeys and is characterized by high morbidity and low mortality rates. The present study aimed firstly at determination of the prevalence rates of B. avium in turkeys reared in Egypt at different ages using various diagnostic methods including clinical examination, histopathology, enzyme-linked immunosorbent assay (ELISA), bacterial culture, and polymerase chain reaction (PCR). Using PCR, virulence-associated genes were detected in the confirmed B. avium isolates. Furthermore, the antibiotic resistance profiles of the confirmed B. avium isolates were examined. The achieved results indicated isolation and identification of B. avium infection at different ages of turkeys reared in Egypt. The overall PCR-confirmed prevalence rate of B. avium was 22.95%. The identified B. avium strains harbored virulence-associated genes responsible for colonization in the respiratory tract of turkeys including Bordetella virulence gene (100%), fimbriae (71.14%), and filamentous hemagglutinin (85.68%). The isolated B. avium strains showed multidrug resistance profiles. B. avium isolates were resistant to penicillin (92.82%), ceftiofur (85.68%), nalidixic acid (78.54%), and lincomycin (71.40%). The identified B. avium strains showed clear sensitivities to both gentamicin and neomycin, suggesting these as possible antimicrobial candidates for the control of B. avium infection in turkeys.

Background Clindamycin is a lincosamide antibiotic used to treat staphylococcal and streptococcal infections. Reports of clinical Streptococcus agalactiae isolates with the rare lincosamide resistance/macrolide susceptibility (LR/MS) phenotype are increasing worldwide. In this study, we characterised three clinical S. agalactiae strains with the unusual L phenotype from China. Methods Three clinical S. agalactiae strains, Sag3, Sag27 and Sag4104, with the L phenotype were identified from 186 isolates collected from 2016 to 2018 in Shanghai, China. The MICs of clindamycin, erythromycin, tetracycline, levofloxacin, and penicillin were determined using Etest. PCR for the lnu(B) gene was conducted. Whole genome sequencing and sequence analysis were carried out to investigate the genetic context of lnu(B). Efforts to transfer lincomycin resistance by conjugation and to identify the circular form by inverse PCR were made. Results Sag3, Sag27, and Sag4104 were susceptible to erythromycin (MIC ≤0.25 mg/L) but resistant to clindamycin (MIC ≥1 mg/L). lnu(B) was found to be responsible for the L phenotype. lnu(B) in Sag3 and Sag27 were chromosomally located in an aadE-spw-lsa(E)-lnu(B) resistance gene cluster adjacent to an upstream 7-kb tet(L)-cat resistance gene cluster. Two resistance gene clusters were flanked by the IS6-like element, IS1216. Sag4104 only contained partial genes of aadE-spw-lsa(E)-lnu(B) resistance gene cluster and was also flanked by IS1216. Conclusion These results established the presence of the L phenotype associated with lnu(B) in clinical S. agalactiae isolates in China. The lnu(B)-containing multi-resistance gene cluster possibly acts as a composite transposon flanked by IS1216 and as a vehicle for the dissemination of multidrug resistance among S. agalactiae.

E. coli is one of the most common isolates in avian diseases, which causes colibacillosis. In this study a total of 114 E. coli isolates were recovered from 500 chicken samples including heart, liver and rectal swabs samples with a percentage of 12.8 %. from broilers with a history of respiratory manifestations and postmortem lesions (pericarditis, per hepatitis and air saculitis) in Sharkia province. The recovered E. coli isolates were typed serologically into 10 different 'O' groups including O1, O2, O26, O44, O78, O91, O111, O121, O125 and O128. Untypeable isolates were also recovered. The results of congo red test revealed that (40/500) of E. coli isolates from rectal swabs were positive. The susceptibility of identified E. coli isolates to a panel of seventeen commonly used antimicrobial agents and E. coli isolates showed the the highest resistance against lincomycin (100%), tetracycline (96.8%), streptomycin (93.7%), trimethoprim sulfamethoxazole, ampicillin, erythromycin and florfenicol (92.18%), which being the least effective antimicrobial agent aganist E. coli, while the least resistance rate was detected against apramycin (32.18%).

Colibacillosis is a complicated disease causing severe economic losses and challenging veterinarians and producers. Therefore, this study aimed to characterize avian pathogenic Escherichia coli (APEC) strains causing respiratory troubles in chickens. Thirty broiler chicken flocks (2013-2016 outbreaks) at age of 17-35 days from Sharkia, Ismailia, Dakahlia and Sinai showed respiratory troubles and greenish diarrhea. The postmortem findings revealed typical colisepticemia picture including air sacculitis, fibrinous pericarditis and perihepatitis. The percentage of APEC isolation was 100 % while 10 flocks suffered mixed infections. From 284 collected samples (air sacs, heart blood, lungs and liver), E. coli isolation was mostly from air sacs (76.1 %) and lung (73.2 %) followed by heart blood (67.6%) and liver (54.9%). Based on serogrouping, the most common serogroups were O78 and O2 with percentage of 15% each. Based on antimicrobial disc diffusion test, the lowest (32.7 %) and highest resistance (100 %) were to doxycycline versus lincomycin, spiramycin, oxacillin and amoxicillin. PCR analysis for 55 MDR E. coli isolates revealed 3 antibiotic resistance genes (blaTEM (87.3 %), blaCTX-M (85.5 %) and blaOXA (5.5 %)) and 6 virulence genes in two multiplex PCR (iucD (96 %), Fim H (92.7 %), iss (76.4 %), ompT (58.2 %), tsh (45.5 %) and cvaC (9 %). An association between virulence and multidrug resistance genes in E. coli was concluded, that hindered the control strategy. Therefore, alternative strategies were necessary to minimize the antibiotic use and reduce the virulent strains occurrence.

A total of 100 diseased broiler chickens of average age 22-28 days old were collected from different farms located in Dakahlia Governorate. All samples were subjected to clinical and postmortem (P.M) examination as well as bacteriological examination for detection of infection. Thus, E. coli was recovered from examined organs of 37 chickens with an incidence rate of 37 % (37 out of 100). Accuratly, 10 E. coli serogroupes were identified in 28 positive samples and the most predominant serogroup were O125 16%, O91 14%, O1 11%, O26 K60 11% & O86 K64 8 & O128 5% & O55 K59 3% & O166 3% & O103 3% and O144 3% and untypable E. coli (24 %). Studying antibiogram resistance pattern of E. coli isolates revealed that all isolates demonstrated multidrug resistence pattern. The highest resistance rates were recorded against Lincomycin (100%) and lowest are Colistin (7.14%) and other tested antibiotics showed variations regarding their resistance patterns. The most predominant serotypes of this study have the ability to form biofilm on the inner wall of the glass. PCR was done for detection of resistant genes (blaTEM and tetA(A)) and virulence genes (csgD, adrA, eaeA and fimH) in the 10 tested isolated serotypes and the results revelead that, 100% and 90% &100%, 90%, 90% and 100% were positive for resistant genes and virulence genes, respectively and investigate the relationship between them was discovered. By studying the effect of Olive Leaf Extract on multidrug resistant isolates, results were revealed that all tested serotypes are sensitive to Olive Leaf Extract (10% conc.).

Urinary tract infections (UTI) are considered one of the most important diseases of sows due to its close relationship with reproductive problems such as reduced litter size, increase in the rate of return to estrous, vulvar discharge, abortion, mastitis and anestrus. Actinobaculum suis is one of the main agents involved in porcine urinary tract infection and is responsible for the most severe and fatal cases in sows. In the present report, 23 A. suis strains isolated from a sow and boars in Brazil were identified by PCR and further characterized by broth microdilution, molecular typing by pulsed-field gel electrophoresis (PFGE), single-enzyme amplified fragment length polymorphism (SE-AFLP), and whole-genome sequencing. All strains were sensitive to ceftiofur, linezolid, nitrofurantoin, quinupristin-dalfopristin and vancomycin. Ciprofloxacin, daptomycin, lincomycin, erythromycin and tylosin resistance was observed in 100% of tested strains. Tetracycline and tigecycline also presented high resistance rates (87% and 30.4%, respectively). PFGE with eight different restriction enzymes and three programs did not enable strain characterization; however, all strains were typed by SE-AFLP that clustered strains according to their origin, thus proving an effective tool for A. suis genotyping. Whole-genome sequencing and comparative analysis enabled species differentiation from closely related genus. This is the first report of genomic characterization of A. suis.

Panax ginseng is a traditional medicinal plant used in most Asian countries to cure many diseases. The benefits of ginseng are due to its primary active component, polysaccharides. Gut microbiota dysbiosis is a worldwide problem associating with antibiotic use. The objective of this study was to investigate the effects of ginseng polysaccharides (WGP) on the diversity of the gut microbiota in mice with antibiotic-associated diarrhea. Compared to diarrhea mice, WGP significantly changed the composition and diversity of the gut microbiota. Specifically, WGP increased the relative abundance of the phylum Firmicutes and decreased the relative abundance of the phyla Bacteroidetes, Proteobacteria and Actinobacteria. At the genus level, WGP increased the relative abundance of Lactobacillus, Lactococcus, and Streptococcus, but decreased the relative abundance of Bacteroides. The key phylotype of beneficial bacteria in the gut microbiota that responded to WGP was Lactobacillus. In addition, WGP also reversed carbohydrate, amino acid and energy metabolism to normal levels, thereby promoting the recovery of the mucosal structure. Taken collectively, our results indicate that WGP altered the composition and diversity of the gut microbiota in mice with antibiotic-associated diarrhea, restored the gut microbiota, balanced metabolic processes, and promoted the recovery of the mucosa.

Introduction: The aim of the study was to evaluate the occurrence of enterococci in inflammatory secretions from mastitic bovine udders and to assess their antimicrobial resistance. Material and Methods: A total of 2,000 mastitic milk samples from cows were tested in 2014–2017. The isolation of enterococci was performed by precultivation in buffered peptone water, selective multiplication in a broth with sodium azide and cristal violet, and cultivation on Slanetz and Bartley agar. The identification of enterococci was carried out using Api rapid ID 32 strep kits. The antimicrobial susceptibility was evaluated using the MIC technique. Results: Enterococci were isolated from 426 samples (21.3%). Enterococcus faecalis was the predominant species (360 strains), followed by E. faecium (35 isolates), and small numbers of others. The highest level of resistance was observed to lincomycin, tetracycline, quinupristin/dalfopristin (Synercid), erythromycin, kanamycin, streptomycin, chloramphenicol, and tylosin. Single strains were resistant to vancomycin and ciprofloxacin. All isolates were sensitive to daptomycin. E. faecalis presented a higher level of resistance in comparison to E. faecium, except to nitrofurantoin. Conclusion: The results showed frequent occurrence of enterococci in mastitic cow’s milk and confirmed the high rate of their antimicrobial resistance.

Şen, Fatih (Dumlupınar-Author), Broad-spectrum antibiotics have been widely used in the treatment of many systemic and local infections in humans and animals. Herein, we aimed to determine the synergistic and antagonistic effects of phenylalanine with antibiotics cefoxitin, amoxicillin, vancomycin, lincomycin, and bacitracin against 14 pathogenic bacteria. The effect of antibiotics, either alone or in combination with this biomolecular liquid, was tested using the disk diffusion method against different bacteria. The addition of phenylalanine to antibiotic disks directly affected their antimicrobial activity. All the antibiotics used did not show any antimicrobial activity against Staphylococcus haemolyticus when used alone. However, in combination with phenylalanine, each antibiotic inhibited the growth of S. haemolyticus. The use of this biomolecular liquid together with amoxicillin and vancomycin also increased the antimicrobial activity against Enterococcus durans. The use of phenylalanine in combination with antibiotics also resulted in antagonistic effects on some pathogens. Further, the effects of antibiotics in combination with phenylalanine on different bacterial pathogens were investigated in vitro. Results provide valuable information to further our understanding of the molecular mechanism of action of antibiotics and to improve their efficacy against bacterial pathogens.

Mycoplasma hyorhinis is a common pathogen of swine causing mainly polyserositis and arthritis, but it has also been implicated as a cause of pneumonia. The economic losses due to M. hyorhinis infection could be reduced by antibiotic treatment. The aim of this study was to determine minimal inhibitory concentrations (MIC) of antibiotics potentially used to combat M. hyorhinis in swine production. Thirty-eight Hungarian M. hyorhinis strains isolated between 2014 and 2017 were examined by microbroth dilution tests for fifteen antimicrobial agents. Low MIC values of tetracyclines (MIC50 0.078 μg/ml for doxycycline, ≤0.25 μg/ml for oxytetracycline) and pleuromutilins (MIC50 0.156 μg/ml for tiamulin, ≤0.039 μg/ml for valnemulin) were detected against all strains. Fluoroquinolones (MIC50 0.625 μg/ml), gentamicin (MIC50 1 μg/ml) and florfenicol (MIC50 2 μg/ml) inhibited the growth of Hungarian isolates at moderate MIC values. Most of the strains were inhibited by spectinomycin with low or moderate MIC values (MIC50 4 μg/ml) except one strain (>64 μg/ml). Numerous isolates showed decreased susceptibility to macrolides and lincomycin (MIC90 >64 for tylosin, tilmicosin, tulathromycin, gamithromycin, lincomycin, 8 μg/ml for tylvalosin). This study serves as evidence for the increasing resistance to macrolides and lincomycin in mycoplasmas, and also reports the occurrence of strains with extremely high MIC values to spectinomycin thus emphasizes the importance of the prudent use of antibiotics. Based on our results, tetracyclines and pleuromutilins are the most active compounds in vitro against the Hungarian M. hyorhinis strains.

The main factor in the treatment of suppurative and inflammatory processes is the timely optimization of treatment measures taking into account the nature of the microflora and its susceptibility to antimicrobial drugs. The purpose of the study is to monitor the spectrum of microorganisms – pathogens of purulent-inflammatory processes of soft tissues in surgical patients; study of the sensitivity of isolated strains to antibiotics. The material was collected in accordance with aseptic rules. The identification of a pure culture of bacteria was carried out according to morphological, culture, biochemical properties, and the presence of virulence enzymes. Sensitivity of bacteria to antibiotics was determined by the standard disks method (by Kirby-Bauer’s). 255 patients with purulent-inflammatory processes of soft tissues were examined for the period from 2014 to 2017. 229 strains of isolated bacteria were included to Escherichia coli, Citrobacer freundii, Enterobacter cloacae, E.aerogenes, Proteus vulgaris, Staphylococcus aureus, S.epidermidis, Streptococcus pyogenes, S.viridians, S.agalactiae, Pseudomonas aeruginosa. The main cause of purulent-inflammatory processes of soft tissues is Staphylococci (67,2%). Compared to previous studies, the number of P.aeruginosa isolated cultures increased (7.9%). In monoculture and in association with other microorganisms, E. coli (9.6% of cases), E.cloacae et aerogenes (3.9% of cases), P.vulgaris (3.9% of cases), C.freundi (2.5% of cases), S.agalactiae, S.pyogenes, S.viridans (3.5%). The number of associated sows reaches 12%. Clinical strains of microorganisms remain most sensitive to fluoroquinolones, cephalosporins, and also retains high sensitivity to gentamicin, lincomycin, rifampicin, which is important for empirical antibiotic therapy. To increase the effectiveness of antibacterial therapy, strict adherence to the mode of appointment of antibiotics, justification of indications, a combination of antibiotics of different spectrum of action, mandatory correction after determining the sensitivity of the pathogen.