Bovine respiratory disease caused by Mycoplasma bovis is a major health problem of cattle worldwide. It inflicts considerable financial losses on beef herds and is the most common cause of mortality in dairy cattle. Bacteriological examination of 35 nasal cavity samples from calves younger than three months of age identified Mycoplasma bovis in eight (22.9%) samples. These cattle were followed until 17 months of age, and repeated examination of nasal cavity samples before necropsy identified Mycoplasma bovis in four (11.4%) samples. At necropsy and lung samples for bacteriological and histological examination were collected. To identify microorganisms from the Mollicutes class isolated from the nasal cavities of cattle we used the PCR method. Furthermore, Mycoplasma bovis was identified on the grounds of biochemical characteristics and by the disk growth inhibition test. The organism was found in 5.7% of calves younger than three months of age in combination with Pasteurella spp. Mycoplasma bovis in combination with Pasteurella multocida and Mannheimia haemolytica was isolated from 5.7% and 2.9% of cattle at 17 months. However, Pasteurella multocida was common in cattle at 17 months and Mannheimia haemolytica was isolated from both age groups of cattle. Histopathological examination of lung samples revealed broncho-interstitial pneumonia in 14.3% of samples. Mycoplasma bovis was isolated from 60.0% of broncho-insterstitial pneumonia cases. The organism was isolated more frequently from the group of calves rather than from the cattle group (P < 0.05). The most common bacterial agents were Pasteurella multocida and Mannheimia haemolytica.
ABSTRACT:The purpose of this study was to determine the antibacterial susceptibility of field isolates of Mycoplasma bovis originating from the upper respiratory tract of cattle of different ages. Bacteriological examination of 90 nasal swabs collected from calves at three months of age identified M. bovis in 31 (34.44%) samples. Seventeen (18.88%) of these animals still housed M. bovis in their nasal cavity at nine months and five animals (5.55%) still at seventeen months of age. M. bovis were confirmed by biochemical and antigenic methods. To confirm that these belonged to the M. bovis species isolated mycoplasmas were tested using the PCR method. Fifteen field strains of M. bovis isolated from the same cattle at three, nine and seventeen months (five strains from each age group) were selected for antibacterial susceptibility testing against six groups of antimicrobial agents using an agar dilution method. The MIC 90 ranges established for tylosin, tulathromycin, enrofloxacin, florfenicol and lincomycin were 0.39-0.78 µg/ml, 0.50-1.00 µg/ml, 0.78-1.56 µg/ml, 3.12 µg/ml and 0.39-0.78 µg/ml, respectively. The range of MIC 90 for oxytetracycline was from 50 to 100 µg/ml. Preliminary examination of the antimicrobial susceptibility of field strains of M. bovis did not reveal significant differences between different age groups of cattle. After evaluation of the MIC 90 data with the SPSS 13.0 statistical package it was found that M. bovis isolates from animals at three, nine and seventeen months were similarly susceptible to tylosin and tulathromycin. Statistically significant differences in susceptibility of M. bovis isolated from cattle of different ages were found to florfenicol compared with tulathromycin (P < 0.01), lincomycin (P < 0.01) and enrofloxacin (P < 0.05). The susceptibility of all M. bovis isolates to oxytetracycline and penicillin G significantly differed from the sensitivity to all other antimicrobial agents used in the present study (P < 0.05). The in vitro susceptibility test showed that field isolates of M. bovis isolated from cattle of different ages were similarly sensitive to tylosin, tulathromycin, lincomycin and enrofloxacin. It was also determined that the field strains are resistant to oxytetracycline.
ABSTRACT:The objective of this study was to evaluate the prevalence of coagulase-negative staphylococci in healthy dogs and to determine whether methicillin-resistant staphylococci expressed the mecA gene. Nasal and rectal swab samples were taken from 50 clinically healthy dogs. The prevalence of coagulase-negative staphylococci was evaluated according to phenotypic properties. The agar diffusion method was applied to evaluate antimicrobial resistance and the prevalence of methicillin resistance was determined using PCR analysing the mecA gene. A total of 59 coagulase-negative staphylococcus strains were isolated from the nostrils and rectums of 37 (74%) clinically healthy dogs. The prevalence of coagulase-negative staphylococci in female dogs was significantly higher compared with male dogs (P < 0.05). The results of antimicrobial susceptibility testing showed that 6.7% of the strains were resistant to oxacillin, 23.7% were resistant to penicillin, 22% to ampicillin and 16.9% to erythromycin. The mecA PCR revealed one oxacillin-sensitive and four oxacillin-resistant coagulase-negative staphylococci strains to be mecA carriers. Staphylococcus sciuri (60%) and Staphylococcus warneri (20%) were the most prevalent species among methicillin-resistant coagulase negative staphylococci. High antimicrobial resistance rates for these bacteria were observed against penicillin (100%), ampicillin (100%), oxacillin (80%), erythromycin (80%) and gentamicin (60%). All strains were susceptible to vancomycin and enrofloxacin. It is assumed that methicillin-resistance genes evolved in coagulase-negative staphylococcus and were then horizontally transferred among staphylococci.
The aim of this study was to detect Mycoplasma species in the respiratory tract of 110, 310 and 510 day-old groups of cattle by serological, bacteriological and histopathological investigations. Antibodies against M. bovis were found in 75% of the 110 day-old, in 50% -of the 310 day-old and in 55% -of the 510 day-old groups of cattle.Bacteriological examination of the samples from nasal cavities revealed that Mycoplasma carriers were found in 60% of the 110 day-old group of cattle, 40% of the 310 day-old and 40% of the 510 day-old group of cattle. Using the PCR method Mycoplasma was isolated from 25% of lung samples of the 510 day-old group of cattle. Mycoplasma bovis and Mycoplasma dispar were confirmed by serological investigations. Foci of bronchointerstitial pneumonia were determined by histopathological examination in 27.5% of lung samples. Mycoplasma bovis was isolated in 72.7% of bronchointerstitial pneumonia cases. Data processing with an SPSS 13.0 statistical package led to the conclusion that Mycoplasma bovis was found more frequently in the 110 day-old group of cattle (the youngest age group in this study) rather than in the 310 and 510 day-old groups of cattle (χ 2 = 6.531; p = 0.038). The results obtained led to the conclusion that serological, bacteriological and histopathological examinations are important in detecting particular animal -carriers of Mycoplasma.
The demand for healthy foods without artificial food additives is constantly increasing. Hence, natural food preservation methods using bioprotective cultures could be an alternative to chemical preservatives. Thus, the main purpose of this work was to screen the indigenous lactobacilli isolated from fermented cow milk for their safety and antifungal activity to select the safe strain with the strongest fungicidal properties for the development of bioprotective acid whey protein concentrate (AWPC) based fermentates and their coatings intended for fresh cheese quality maintenance. Therefore, 12 lactobacilli strains were isolated and identified from raw fermented cow milk as protective cultures. The safety of the stains was determined by applying antibiotic susceptibility, haemolytic and enzymatic evaluation. Only one strain, Lacticaseibacillus paracasei A11, met all safety requirements and demonstrated a broad spectrum of antifungal activity in vitro. The strain was cultivated in AWPC for 48 h and grew well (biomass yield 8 log10 cfu mL−1). L. paracasei A11 AWPC fermentate was used as a vehicle for protective culture in the development of pectin-AWPC-based edible coating. Both the fermentate and coating were tested for their antimicrobial properties on fresh acid-curd cheese. Coating with L. paracasei A11 strain reduced yeast and mould counts by 1.0–1.5 log10 cfu mL−1 (p ≤ 0.001) during cheese storage (14 days), simultaneously preserving its flavour and prolonging the shelf life for six days.
Spread of antibiotic resistance via mobile genetic elements associates with transfer of genes providing resistance against multiple antibiotics. Use of various comparative genomics analysis techniques enables to find intrinsic and acquired genes associated with phenotypic antimicrobial resistance (AMR) in Campylobacter jejuni genome sequences with exceptionally high-level multidrug resistance. In this study, we used whole genome sequences of seven C. jejuni to identify isolate-specific genomic features associated with resistance and virulence determinants and their role in multidrug resistance (MDR). All isolates were phenotypically highly resistant to tetracycline, ciprofloxacin, and ceftriaxone (MIC range from 64 to ≥256 µg/mL). Besides, two C. jejuni isolates were resistant to gentamicin, and one was resistant to erythromycin. The extensive drug-resistance profiles were confirmed for the two C. jejuni isolates assigned to ST-4447 (CC179). The most occurring genetic antimicrobial-resistance determinants were tetO, beta-lactamase, and multidrug efflux pumps. In this study, mobile genetic elements (MGEs) were detected in genomic islands carrying genes that confer resistance to MDR, underline their importance for disseminating antibiotic resistance in C. jejuni. The genomic approach showed a diverse distribution of virulence markers, including both plasmids and phage sequences that serve as horizontal gene transfer tools. The study findings describe in silico prediction of AMR and virulence genetics determinants combined with phenotypic AMR detection in multidrug-resistant C. jejuni isolates from Lithuania.
The aim of this study was to make a survey of the presence of Mycoplasma dispar on a cattle breeding farm and to determine antimicrobial susceptibility of the isolates.The study was carried out at a farm in Lithuania. Nasal swabs for bacteriological investigation were collected from ninety dairy, beef and mixed type of cattle from 90 to 300 days of age. Mycoplasma cultivation procedures were carried out using Friis selective media. To confirm the presence of Mollicutes class the polymerase chain reaction (PCR) was used. Isolates were identified according to biochemical and antigenic characteristics.The minimum inhibitory concentration of twenty field isolates of Mycoplasma dispar to tulathromycin, tylosin, lincomycin, enrofloxacin, florfenicol, and oxytetracycline was determined by using a micro-broth dilution method.Mycoplasma dispar was detected in the nasal cavity of 15 out of 84 clinically healthy animals (17.9 %), and in 5 out of 6 animals with respiratory disorders (83.3 %). The isolates were most susceptible to tulathromycin, lincomycin, enrofloxacin and florfenicol. Three (15 %) isolates were resistant to oxytetracycline.The susceptibility to oxytetracycline significantly differed between Mycoplasma dispar isolates compared to the susceptibility of tulathromycin (P < 0.001), lincomycin (P < 0.001) tylosin (P < 0.001), enrofloxacin (P < 0.001), and florfenicol (P < 0.001).
the objective of this study was to establish the prevalence and antimicrobial resistant patterns of commensal Escherichia coli isolated from healthy dogs. In total, 55 rectal swabs from clinically healthy dogs, kept outside (n = 20), and inside a house (n = 20) and from dogs kept at an animal shelter (n = 15), were collected for isolation of Escherichia coli. resistance patterns to 11 antimicrobial agents were tested using e-test (epsilometer test) to determine the MIC (Minimum Inhibitory Concentration). Multiplex polymerase chain reaction (M-PCR) amplification was used to detect selected genes conferring resistance to beta-lactams, tetracycline, aminoglycoside, sulphanilamide, quinolone, and phenicol classes of antimicrobial agents. Forty-eight E. coli strains were isolated from 55 (87.3%) dogs. Multi-drug resistance was present in 38% of resistant isolates. E. coli isolates showed the highest resistance rates to streptomycin (85.1%), ampicillin (77.1%), sulfamethoxazole (70.8%) and tetracycline (64.6%). The isolates were most sensitive to enrofloxacin (87.5%) and chloramphenicol (72.9%). Bacterial resistance genes were determined to tetracycline (tet) (9.7%) trimethoprim/sulfamethoxazole (dfrA1) (16.7%,), and chloramphenicol (catA1) (5.5%). In general, the prevalence of antimicrobial resistance in E. coli isolates from shelter dogs population was higher than in those from dogs kept inside and outside (P<0.05). Companion animals in Lithuania are important reservoirs of resistant Escherichia coli strains. Only appropriate use of antimicrobials can minimize the spread of resistant bacteria among healthy and diseased animals and humans.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.