Antimicrobial resistance trends in fecal Salmonella isolates from northern California dairy cattle admitted to a veterinary teaching hospital, 2002-2016

Abstract

Nontyphoidal Salmonella infections contribute to approximately 1.2 million annual illnesses in the United States. Historical and recent outbreaks have been associated with dairy products, ground beef, and direct contact with cattle. Salmonella antimicrobial resistance (AMR) is a serious concern that can reduce successful treatment of infections, increasing recovery time, medical costs, and mortality rates in humans and animals. This highlights the need to track AMR in Salmonella isolated from cattle to improve treatment plans, manage trends in AMR, and prevent future AMR development. A total of 242 Salmonella isolates were retrieved from 9,162 cattle fecal samples submitted to the University of California, Davis Veterinary Medical Teaching Hospital from 2002 to 2016. These isolates were tested for antimicrobial susceptibility using a standardized broth dilution panel. Multidrug resistance (MDR) to three or more classes of antimicrobials was observed in 50.8% of isolates, and the most common MDR pattern was amoxicillin-ampicillin-cefoxitin-ceftiofur-ceftriaxone-chloramphenicol-streptomycin-tetracycline (23.2%). There were significantly greater odds for antimicrobial resistance to aminoglycosides (OR: 2.03, 95% CI: 1.1–3.7), penicillins (OR: 1.87, 95% CI: 1.007–3.5), and tetracyclines (OR: 1.87, 95% CI: 1.017–3.4) for the 2002–2009 period when compared to the 2010–2016 period. The most prevalent MDR serotypes were Newport (100% MDR, n = 52), Typhimurium (100%, n = 20), and Dublin (71% MDR, n = 46). Risk factors associated with higher odds for isolating MDR Salmonella included isolates from calves when compared to adult cattle (OR: 22.0; 95% C.I.: 3.9–125.7), and isolates obtained from cattle suspect of having salmonellosis versus from the infectious disease control surveillance program (OR:13.7; 95%C.I.: 2.8–66.8). Despite a temporal trend for reduced AMR to most antimicrobial drug classes, a lack of this observed in the 2002–2009 period when compared to the 2010–2016 period for important drug classes such as cephalosporins (OR: 1.6, 95% CI: 0.87–3.1), and a trend for temporal increase in resistant to quinolones drugs (P value 0.004) highlight the relevance of AMR surveillance in cattle with Salmonella infections with the aim of targeting future prophylactic interventions.

Antibiotic resistance in Salmonella enterica isolated from dairy calves in Uruguay

“…In this study, S. Typhimurium was isolated from calves with diarrhoea, septicaemia and mortality, as reported in previous works [7,21]. The serotype S. Anatum was only isolated from faecal samples from only one dairy farm (Table S1).…”

Detection of Cephalosporin and Fluoroquinolone Resistance Genes via Novel Multiplex qPCR in Fecal Salmonella Isolates From Northern Californian Dairy Cattle, 2002–2016

“…A total of 110 Salmonella isolates were selected for qPCR analysis from a collection of 242 Salmonella isolates recovered from 9162 bovine fecal samples submitted to the University of California, Davis William R. Pritchard VMTH microbiology laboratory between January 1, 2002 and December 31, 2016 as detailed previously ( Davidson et al, 2018 ). Sixty-eight isolates were recovered from dairy cattle exhibiting clinical signs of Salmonella infection, while 42 isolates were recovered from asymptomatic dairy cattle through the VMTH Infectious Disease Control (IDC) program.…”

Isolation and Identification of Salmonella spp. from Broiler Chicken Meat in Sri Lanka and their Antibiotic Resistance

“…Illnesses that were once easily treatable with antibiotics are becoming more difficult to cure due to the emergence of resistance to present generation drugs. Rapid annual development of antibiotic resistance in nontyphoidal Salmonella serovars has become a significant problem (Angelo et al, 2016;Davidson et al, 2018). In a similar study aimed at examining the prevalence and antimicrobial resistance of Salmonella isolates from broiler chickens, pigs and their associated meat products revealed that the multidrug resistance was 34% in Thailand and 52% in Cambodia.…”

“…Despite to the increasing incidence of ciproflioxacin resistant Salmonella in some countries (Threlfall et al, 2002;Medalla et al, 2013) several studies have found that there is a decreasing tendency of developing resistance in Salmonella against few antibiotics and it is in agreement with the findings of the current study. For instance, Davidson et al, (2018) have found no isolate resistant to ciprofloxacin among total of 242 Salmonella isolates. In other studies too, monitoring Salmonella isolates have shown that there was no resistance to ciprofloxacin and nalidixic acid (Cummings et al, 2013;Davidson et al, 2018).…”

“…For instance, Davidson et al, (2018) have found no isolate resistant to ciprofloxacin among total of 242 Salmonella isolates. In other studies too, monitoring Salmonella isolates have shown that there was no resistance to ciprofloxacin and nalidixic acid (Cummings et al, 2013;Davidson et al, 2018). A study conducted on Salmonella enterica isolated from 4976 clinical samples observed parallel findings that showed a tendency for gradual declining of resistance for gentamicin, trimethoprim as well as neomycin (Valenzuela et al, 2017).…”