Listeria monocytogenes in raw milk, milking equipment and dairy workers: Molecular characterization and antimicrobial resistance patterns.

OBJECTIVES: The aim of this study was to evaluate the genetic relatedness and patterns of antimicrobial resistance amongst L. monocytogenes isolated from raw milk, milking equipment, and hand swabs from workers in dairy farms. METHODS: A total of 300 samples of raw milk, milking equipment, and hand swabs were collected from four dairy farms to examine the presence of Listeria species. Suspected isolates were further identified by VITEK-2 system and Polymerase Chain Reaction (PCR). Antimicrobial susceptibility of the L. monocytogenes isolates was determined, and genotyping analysis was performed by enterobacterial repetitive intergenic consensus-polymerase chain reaction (ERIC-PCR). RESULTS: Listeria spp. was isolated from 79 (26.3%) of the 300 samples, including 29 (36.7%), 32 (40.5%), and 18 (22.8%) isolates found in raw milk, milking equipment, and hand swabs, respectively. L. monocytogenes was the most common isolated (87.3%) species, while the remaining Listeria isolates were L. innocua (12.7%). Among the 69 L. monocytogenes isolates, 42 (60.8%) showed the mutual presence of hlyA, prfA, inlA, and inlB virulence-associated genes. L. monocytogenes isolates from raw milk, milking equipment, and hand swabs showed high genetic relatedness. The potentially virulent L. monocytogenes isolates were most frequently resistance to tetracycline and clindamycin (81%, each) followed by rifampicin (71.4%), whereas, antimicrobial susceptibility was most frequently observed for ampicillin, levofloxacin, moxifloxacin, linezolid, and tigecycline (100%, each). Furthermore, 88% of L. monocytogenes isolates showed multidrug-resistance. CONCLUSIONS: The findings of this study show that the contamination of dairy farms with L. monocytogenes is relatively high, and highlight the emergence of multi-drug resistant L. monocytogenes in dairy farms. However, ampicillin is a good choice for treatment of listeriosis in the study area.

The diagnostic accuracy of acute phase proteins and proinflammatory cytokines in sheep with pneumonic pasteurellosis.

The goal of this study was to assess the diagnostic accuracy of acute phase proteins and proinflammatory cytokines in sheep with pneumonic pasteurellosis. Blood samples were collected from 56 sheep (36 naturally infected with Pasteurella multocida and 20 healthy controls) belonging to one farm in Eastern region, Saudi Arabia. Serum samples were evaluated for acute phase proteins (Haptoglobin (Hp), serum amyloid A (SAA) and fibrinogen (Fb)), and the proinflammatory cytokines (interleukins (IL-1α, IL-1ß, and IL-6), tumor necrosis factor-alpha (TNF-α), and interferon-gamma (IFN-ϒ)). Additionally, nasopharyngeal swabs and bronchoalveolar lavages were collected from all animals for bacteriological examinations. Receiver operating characteristic curve was used to assess the diagnostic performance of each parameter. All parameters showed moderate to high degree of positive correlation with case-control status. There was no significant difference in the area under the curve (AUC) among acute phase proteins; however, both Hp and SAA showed better sensitivity and specificity than Fb. The proinflammatory cytokines (IL1-α, IL1-ß, and IL6) showed similar and highly accurate diagnostic performance (AUC > 0.9), whereas IFN-ϒ was moderately accurate (AUC = 0.79). In conclusion, this study confirms the value of acute phase proteins and cytokines as diagnostic biomarkers of naturally occuring pneumonic pasteurellosis in sheep.

Acute phase proteins as biomarkers of urinary tract infection in dairy cows: diagnostic and prognostic accuracy.

The aims of this study were to investigate the level of acute phase proteins in dairy cows with urinary tract infection (UTI) and to evaluate their diagnostic and prognostic value. Eighty-four lactating cows with clinical and laboratory evidence of UTI and 15 healthy controls were included in this study. Serum samples were evaluated for the levels of Haptoglobin (Hp), serum amyloid A (SAA), fibrinogen (Fb), α1-Acid glycoprotein (AGP), total protein, and globulin. The diagnostic and prognostic performance of each parameter was evaluated by estimating the area under receiver operating characteristics curve (AUROC). Escherichia coli and Corynebacterium spp. were the primary bacteria associated with UTI. The levels of serum Hp, SAA, Fb, AGP, total protein, and globulin were significantly higher in UTI cows. Successfully treated cows (n = 51) had lower levels of Hp, SAA, AGP, total protein, and globulin than non-responsive cows. Overall, Hp, SAA, Fb, and AGP showed comparable diagnostic accuracy (AUROC ranged from 0.93 to 0.98). Both Hp and SAA showed high accuracy in predicting treatment response (AUROC > 0.95), whereas Fb level was of no prognostic value (AUROC = 0.48). From this study, acute phase proteins levels can be used as markers for UTI in cows and higher levels of Hp, SAA and AGP are related to poor treatment response.