Pathogens isolated from bovine clinical mastitis and their antimicrobial resistance

This study aimed to isolate aerobic and microaerophilic bacteria from mastitis milk samples, as well as to determine their antibiotic resistance. A total of 196 bovine mastitis milk samples were tested by standard bacteriological methods and with API identification test kits. Antimicrobial susceptibility testing was performed by the Kirby-Bauer disk diffusion method. The results revealed that the predominant isolate was S. aureus, with an isolation rate of 28%, followed by Streptococcus spp. (27%) and E. coli (19%). Isolation rates for Corynebacterium spp., Mycoplasma spp., and Pseudomonas aeruginosa were 11%, 6%, and 4%, respectively. Compared to the bacteria mentioned above, lower percentages were observed for Trueperella pyogenes (2%), Pasteurella multocida (2%), and Klebsiella pneumoniae (1%). A broad evaluation of antimicrobial resistance showed that the pathogens were resistant to tetracycline (68.63%), oxytetracycline (41.57%), ampicillin (39.08%), ceftiofur (38.1%), cephalexin (32.26%), penicillin (31.25%), amoxicillin/clavulanic acid (24.53%), enrofloxacin (24.44%), gentamycin (23.68%), and trimethoprim/sulfamethoxazole (22.09%). This study demonstrated that the sources of bacteria isolated from mastitis bovine milk samples were both contagious and environmental. More importantly, the present results demonstrate a critically high antimicrobial resistance in dairy cattle. For instance, E. coli isolates showed a crucial resistance to commonly used and recommended antimicrobials, including ceftiofur (100%), cephalexin (83.33%), and tetracycline (94.44%). The results of this study may provide valuable information about clinical aspects of bovine mastitis infections and current antimicrobial resistance levels in dairy cattle.

Lungworms (Metastrongylus Spp.) Demonstrated in Domestic Pigs with Respiratory Disease - What was the True Relevance of that?

BackgroundAn outdoor pig herd was affected by severe respiratory disease in one out of three pastures. At necropsy, Mycoplasma hyopneumoniae and Pasteurella multocida were detected in the lungs, as well as the lung worm Metastrongylus apri. The life cycle of Metastrongylus spp. includes earth worms as an intermediate host, and since domesticated pigs mainly are reared indoors lungworms has not been diagnosed in domestic pigs in Sweden for decades, not even in pigs reared outdoors. Therefore, this disease outbreak was scrutinised from the view of validating the impact of Metastrongylus spp..ResultsAt the time of the disease outbreak, neither eggs of Metastrongylus spp. nor Ascaris suum were detected in faeces of pigs aged ten weeks. In contrast, five-months-old pigs at the pasture with respiratory disease shed large amounts of eggs from Ascaris suum, whereas Ascaris suum not was demonstrated in healthy pigs aged six months at another pasture. Low numbers of eggs from Metastrongylus spp. were seen in faecal samples from both these age categories.At slaughter, seven weeks later, ten normal weighted pigs in the preceding healthy batch were compared with ten normal weighted and five small pigs from the affected batch. Healing Mycoplasma-like pneumonic lesions were seen in all groups. Small pigs had more white spot liver lesions, and all small pigs shed eggs of Ascaris suum in faeces, compared to around 50% of the pigs in the normally sized groups. Metastrongylus spp. were demonstrated in 13 of the 25 pigs (52%), %), representing all groups included.ConclusionAs Metastrongylus spp. were demonstrated regardless of health status, and in another healthy outdoor herd, the impact of Metastrongylus spp. on the outbreak of respiratory disease was depreciated. Instead, Metastrongylus spp. was suggested to be common in outdoor production, although rarely diagnosed. The reason for this is because they will escape detection at routine inspection at slaughterhouses, and that they appeared to generally not induce clinical signs of respiratory disease. Instead, a possible association with a high burden of Ascaris suum was suggested to have preceded the severe outbreak with respiratory disease.

Development of an Online Tool for Pasteurella multocida Genotyping and Genotypes of Pasteurella multocida From Different Hosts

Pasteurella multocida is a versatile zoonotic pathogen. Multiple systems have been applied to type P. multocida from different diseases in different hosts. Recently, we found that assigning P. multocida strains by combining their capsular, lipopolysaccharide, and MLST genotypes (marked as capsular: lipopolysaccharide: MLST genotype) could help address the biological characteristics of P. multocida circulation in different hosts. However, there is still lack of a rapid and efficient tool to diagnose P. multocida according to this system. Here, we developed an intelligent genotyping platform PmGT for P. multocida strains according to their whole genome sequences using the web 2.0 technologies. By using PmGT, we determined capsular genotypes, LPS genotypes, and MLST genotypes as well as the main virulence factor genes (VFGs) of P. multocida isolates from different host species based on their whole genome sequences published on NCBI. The results revealed a closer association between the genotypes and pasteurellosis rather than between genotypes and host species. With the advent of high-quality, inexpensive DNA sequencing, PmGT represents a more efficient tool for P. multocida diagnosis in both epidemiological studies and clinical settings.

Detección de Pasteurella multocida, Mannhemia haemolytica, Histophilus somni y Mycoplasma bovis en pulmón de bovinos

In this study, it was aimed to determine of P. multocida, M. haemolytica, H. somni and M. bovis in macroscopically healthy cattle lungs by PCR. The study was carried out on 82 macroscopically healthy cattle lung. DNA extraction was performed to the lung samples. PCR was then performed using all specific primers. By molecular evaluation, positive results were achieved for P. multocida, M. haemolytica, H. somni and M. bovis in 4 (4.8 %), 4 (4.8 %), 6 (7.3 %) and 3 (3.6 %) of the samples, respectively. Mix infections were detected in five samples. Of the samples, two were positive for both P. multocida and M. haemolytica, two were positive for both M. haemolytica and H. somni and one was positive for both P. multocida and H. somni. However, a positive sample, which carried all of pathogens, was not detected. In conclusion, P. multocida, M. haemolytica, H. somni and M. bovis are the important opportunistic pathogens of respiratory tract in cattle and these pathogens have a major role during infections. But multifactorial nature of bovine respiratory disease and immune system affected the formation of the disease. Hence, firstly cattle’s immunity should be strengthened and other conditions should be kept under control.

Antimicrobial Resistance in Isolates from Cattle with Bovine Respiratory Disease in Bavaria, Germany

Patterns of antimicrobial resistance (AMR) regarding Pasteurella multocida (n = 345), Mannheimia haemolytica (n = 273), Truperella pyogenes (n = 119), and Bibersteinia trehalosi (n = 17) isolated from calves, cattle and dairy cows with putative bovine respiratory disease syndrome were determined. The aim of this study was to investigate temporal trends in AMR and the influence of epidemiological parameters for the geographic origin in Bavaria, Germany, between July 2015 and June 2020. Spectinomycin was the only antimicrobial agent with a significant decrease regarding not susceptible isolates within the study period (P. multocida 88.89% to 67.82%, M. haemolytica 90.24% to 68.00%). Regarding P. multocida, significant increasing rates of not susceptible isolates were found for the antimicrobials tulathromycin (5.56% to 26.44%) and tetracycline (18.52% to 57.47%). The proportions of multidrug-resistant (MDR) P. multocida isolates (n = 48) increased significantly from 3.70% to 22.90%. The proportions of MDR M. haemolytica and P. multocida isolates (n = 62) were significantly higher in fattening farms (14.92%) compared to dairy farms (3.29%) and also significantly higher on farms with more than 300 animals (19.49%) compared to farms with 100 animals or less (6.92%). The data underline the importance of the epidemiological farm characteristics, here farm type and herd size regarding the investigation of AMR.

Development of a multiplex PCR assay for the detection of key genes associated with Pasteurella multocida subspecies

The ability to distinguish among the subspecies of Pasteurella multocida isolates is important epidemiologically; however, classification at the subspecies level based on the results of conventional biochemical tests (fermentation of sorbitol and dulcitol) is reportedly not accurate in all cases. Therefore, we developed a rapid, multiplex PCR assay to differentiate among the 3 subspecies of P. multocida. The PCR assay includes the P. multocida species–specific primers KMT1SP6 and KMT1T7 as an internal amplification control, with a newly designed gatD (galactitol-1-phosphate-5-dehydrogenase)-specific primer pair (unique for subsp. gallicida), and primers targeting a 16S rRNA gene region specific for subsp. septica. The subspecies specificity of the PCR was demonstrated by applying the test to a collection of 70 P. multocida isolates, including the Heddleston serovar reference strains; all isolates and strains were assigned correctly. The PCR assay is a sensitive, specific, and highly effective method for the identification of P. multocida subspecies, and an alternative to biochemical test–based differentiation. A possible relationship was noticed between P. multocida subspecies and lipopolysaccharide (LPS) genotype; all but one of the subsp. gallicida strains were isolated only from avian hosts and represented L1 LPS genotype. Subsp. multocida and subsp. septica isolates were classified into 5 and 4 different LPS genotypes, respectively, of which L3 was the only LPS genotype shared between these 2 subspecies.

PATHOMORPHOLOGICAL CHANGES AND BACTERIAL PATHOGENS ASSOCIATED WITH SWINE PNEUMONIAS IN SOUTHWEST NIGERIA

Pneumonia is a major economic threat to swine industry worldwide, however, there is still dearth of information on the pathology and associated pathogens in Nigeria, and these were therefore investigated. Lungs from 408 slaughtered pigs were randomly collected from abattoirs in Abeokuta, Ibadan and Lagos. The lung samples were cultured for bacterial pathogens using standard techniques, while formalin-fixed tissues were processed for histopathological examination. Grossly, the most consistent lesion was bronchopneumonia (35.3%). The main histopathological findings were lymphoid hyperplasia of bronchus-associated lymphoid tissue (BALT) (88.2%), suppurative bronchopneumonia (63.6%), suppurative bronchitis and bronchiolitis with concurrent epithelial hyperplasia (57.1%), as well as thickened alveolar septa due to cellular infiltration consisting predominantly of neutrophils (54.1%). Ten different species of bacteria were isolated from the lung samples in which two or more pathogens were isolated from each sample (82.7%). Pasteurella multocida was the most frequently isolated bacterium (54.8%). Among the bacteria isolated, there were significant (P < 0.05) differences in the frequencies of isolation of β-haemolytic Streptococci, P. multocida, Haemophilus species and Escherichia coli between the pneumonic lungs and apparently normal lungs. The results of bacterial culture, gross and histopathological changes recorded in this study are consistent with bacterial pneumonia possibly caused by most of the bacteria identified in the present study.

Monitoring of bacterial agents isolated from small cattle on the territory of certain regions of the Russian Federation

The paper presents the results of bacterial screening of goat and sheep breeding enterprises in certain regions of Russia (Tver, Moscow, Smolensk regions, as well as the Republic of Mari-El and Tatarstan), conducted in the period from 2018 to 2021. In the course of this work, 556 samples of sectional material (heart, lungs, gastrointestinal tract, spleen, kidneys, liver, lymph nodes, breast, flushes from the genitourinary system, as well as exudate from purulent lesions) were subjected to a comprehensive bacteriological study. As a result of the conducted studies, 1223 isolates belonging to 25 families (111 bacterial species) were isolated and identified (by the method of time-of-flight mass spectrometry MALDI-ToF). According to the data obtained, the incidence of Escherichia coli isolation was 10.95%, Trueperella pyogenes – 5.47%, Staphylococcus aureus – 5.31%, Proteus mirabilis – 4.08%, Mannheimia haemolytica – 4.00%, Enterococcus faecalis – 3.76%, Enterobacter cloacea and Staphylococcus haemolyticus – 3.59%, Streptococcus dysgalactiae – 3.51%, Pasteurella multocida – 3.27%, Acinetobacter lwoffii – 2.78%, Staphylococcus cohnii – 2.61%, Bibersteinia trehalosi – 2.29%, Pseudomonas aeruginosa – 2.12%, Bacillus cereus and Micrococcus luteus – 1.96%, Corynebacterium pseudotuberculosis and Staphylococcus equorum – 1.88%, Aerococcus viridans – 1.80%, Corynebacterium xerosis – 1.72%, Clostridium perfringens, Streptococcus mitis and Streptococcus pyogenes – 1.39%, Staphylococcus chromogenes and Streptococcus entericus – 1.14%, respectively. The incidence of isolation of other types of microorganisms was below 1%. The data obtained indicate the circulation of a wide range of bacteria in goat and sheep breeding enterprises of the Russian Federation, some of which should be positioned as pathogenic flora (for example, Pasteurella multocida, Listeria monocytogenes, Salmonella enteritidis, Salmonella typhimurium, Clostridium perfringens, etc.), some as conditionally pathogenic (Trueperella pyogenes, Staphylococcus aureus, Bibersteinia trehalosi, Mannheimia haemolytica, Pseudomonas aeruginosa, Moraxella bovis, Moraxella bovoculi, etc.), as well as the normal flora of the animal body. It is worth focusing on these data when conducting a survey of livestock enterprises in order to establish an objective epizootic situation, including taking into account the possibility of circulating pathogens of factor diseases.