RESUMEN

Background and Aim: Pseudomonas aeruginosa is an infectious agent of great importance for animals and humans. It causes serious infections that show high resistance to antibiotics. This study investigated the molecular detection of blaOXA-23 gene in antibiotic-resistant P. aeruginosa strains isolated from cows and humans. Materials and Methods: In total, 120 samples, comprised 60 from cows (30 milk and 30 nasal discharge) and 60 from their owners (30 urine and 30 sputum), were individually collected, cultured, and tested for P. aeruginosa through molecular analysis targeting the blaOXA-23 gene. P. aeruginosa antibiotic-resistant isolates were identified by performing antibiotic susceptibility testing and detecting biofilm formation. Results: In total, 74.17% positive P. aeruginosa isolates, including 66.67% and 81.67% for cows and humans, respectively. Subsequently, positive cow isolates were detected in 60% of milk samples and 73.33% of nasal discharge samples; while positive human isolates were detected in 76.67% of urine samples and 86.66% of sputum samples. Targeting blaOXA-23 gene, 58.43% of cultured isolates were positive for P. aeruginosa by polymerase chain reaction. Respectively, positive isolates were detected in 66.67% and 45.46% of cow milk and nasal discharges as well as in 60.87% and 61.54% of human urine and sputum. The antibiotic susceptibility test revealed that all isolates were resistant to all applied antibiotics, particularly imipenem. Results of biofilm formation revealed 67.31% total positives, including 51.43% strong, 34.285% moderate, and 14.285% weak reactions. In addition, although values of the total positive cows and humans differed insignificantly, total positives showed insignificant variation between values of milk and nasal discharges of cows as well as between urine and sputum of humans; however, significant differences were identified in the distribution of strong, moderate, and weak positivity of these samples. Conclusion: Antibiotic overuse contributes extensively to increasing the prevalence of resistant P. aeruginosa isolates carrying the blaOXA-23 gene in both cows and humans. Furthermore, studies in other Iraqi areas are necessary to support our findings. The main limitations include that the number of tested samples is relatively low, and there is a need to use a large number of samples from different sources. Also, the current methods for detection of resistant isolates are still culture-based approaches.

RESUMEN

Background: Staphylococcus aureus is a typical pathogenic agent that causes several morbidities and mortalities which variable largely following the severity of bacteria and activity of host immunity. Aim: Isolation of S. aureus from different cattle infections, molecular detection of nuc gene in positive S. aureus isolates, and identification of the effectiveness of the phagocytic activity. Methods: Totally, 100 cattle with various infections (25 wounds, 25 abscesses, 25 nasal discharges, and 25 ear swaps) were selected and subjected to collection of swabs under controlled conditions. All collected samples were cultured on mannitol salt agar (MSA) and assessed by biochemical tests. Targeting the nuc gene, all study MSA positive isolates were examined molecularly by conventional polymerase chain reaction (PCR), and then subjected to antibiotic susceptibility test. Jugular venous blood was collected from all infected animals in addition to 20 healthy cattle that were selected as a control group to estimate the phagocytic activity of S. aureus isolates. Results: The findings of MSA culture revealed a total of 80 positive samples of S. aureus as 23, 21, 20, and 16 positive isolates for nasal discharge, abscess, wound, and ear swab, respectively; based on its morphology, cultural trait, and biochemical test. Subsequently, PCR assaying of MSA-positive isolates demonstrated an overall 59 positive samples as 14, 16, 12, and 17 positive isolates for nasal discharge, abscess, wound, and ear swabs, respectively. Antibiotic susceptibility testing of S. aureus-positive PCR isolates reported a significantly high sensitivity to chloramphenicol and vancomycin, and a high resistance to penicillin. Finally, there was a considerable decline in phagocytic activity in particular 2 weeks post-infection as a result of bacterial invasion. Conclusion: This study shows a high prevalence of S. aureus in cattle infections, and the protocol includes a regular screening of cattle infection and suitable therapy based on antibacterial susceptibility test is of great importance in the long-term control of the pathogen. However, additional molecular studies targeting other genes of S. aureus and the role of immune markers in different infections should be aimed.

Asunto(s)

Enfermedades de los Bovinos , Infecciones Estafilocócicas , Bovinos , Animales , Staphylococcus aureus/genética , Absceso/veterinaria , Infecciones Estafilocócicas/veterinaria , Antibacterianos/farmacología , Cloranfenicol , Manitol

RESUMEN

Background and Aim: Probiotics are proven beneficial to health since they enhance immunity against dangerous pathogens and increase resistance to illness. Bacteriocin produced by lactic acid bacteria (LAB), demonstrates a broad inhibitory spectrum and therapeutic potential. This study aimed to isolate LAB-producing bacteriocin and investigate the effect of crude bacteriocin on biofilm from methicillin-resistant Staphylococcus aureus (MRSA). Materials and Methods: This study used randomly collected 80 white soft local cheeses (40 each from cows and sheep) from different supermarkets in Basrah Province. The obtained samples were cultured and the bacterial suspension of S. aureus was prepared at 1.5 × 108 cells/mL. The crude bacteriocin extracted from LAB was obtained, and the tube was dried and inverted to detect the biofilm loss at the bottom. Results: There were 67 (83.75%) LAB isolates. Among 40 milk samples collected directly and indirectly, there were 36 (83.33%). Staphylococcus aureus isolates based on conventional bacteriological analysis and biochemical tests. Molecular testing was conducted to identify LAB and MRSA. Depending on genotypic results, the effect of white soft local cheese (cows and sheep) and the amplification results of the 16S rRNA gene were detected in 46 LAB isolates from white soft local cheese from cows and sheep. Based on the molecular identification of the mecA, results on Staphylococcus determined that only 2 of 36 isolates of S. aureus carried the mecA. Moreover, there were 26 (86.66%) isolates (MRSA) from samples of raw milk from local markets and subclinical mastitis in cows. The ability of LAB isolates was tested. The effects of bacteriocin production on preventing biofilm growth and formation were investigated. Results demonstrated that bacteriocin has high activity. Microtiter plates applied to investigate the ability of S. aureus to produce biofilms revealed that all isolates were either weak or moderate biofilm producers, with neither non-biofilm nor strong biofilm producers found among the tested isolates. Conclusion: Lactic acid bacteria demonstrate a high ability to produce bacteriocin. Crude bacteriocin from LAB has a restrictive effect on biofilms produced by MRSA; thus, it can be used to reduce the pathogenicity of this bacterium.