The genetic relatedness and antimicrobial susceptibility profiles of Salmonella isolated from poultry and their environment were determined. One broiler breeder flock (BBF1) and 2 broiler flocks (BF1 ...and BF2) were reared over a 1.75-year period on the same poultry research farm. Hatching eggs were obtained from BBF1 to produce BF1 chicks, while BF2 chicks were progeny of a separate, unsampled broiler breeder flock. BF1 and BF2 were reared in the same housing facilities but 6 mo apart. Salmonella isolates were collected via litter sock sampling (BF1), cecal excision (BF1 and BF2), or cloacal swabs (BBF1). Serotyping identified Salmonella enterica subsp. enterica serovar Altona (SA) in BBF1 and S. enterica subsp. enterica serovar Senftenberg (SS) in BF1 and BF2. Genotypic fingerprinting was achieved with Rep-PCR using the (GTG)5 primer and revealed sequence homology among Senftenberg isolates from BF1 and BF2. For each isolate, the minimum inhibitory concentration was determined for 27 antimicrobial agents using Sensititre plates with formularies specific to antimicrobials used in poultry production or those used to control gram negative pathogens. Isolates from the 3 flocks were resistant to clindamycin, erythromycin, novobiocin, penicillin, and tylosin tartrate and demonstrated intermediate resistance to azithromycin, florfenicol, and spectinomycin. These data demonstrated that serovar Altona and Senftenberg were harbored by poultry, the latter appeared to persist in broiler flocks, and both serotypes shared similar patterns of antimicrobial susceptibility in an integrated research operation. In the case of multiple Salmonella isolates, combining genotypic fingerprinting methods with serotyping of representative isolates would reduce the number of samples required for serotyping and more clearly identify relatedness of isolates. These methods facilitate effective surveillance in poultry production systems, thus allowing for implementation of precise Salmonella control measures.
Pathogenic strains of Enterococcus cecorum (EC) expressing multidrug resistance have emerged. In National Antimicrobial Resistance Monitoring System (NARMS) data, EC is rarely recovered from ...chickens. Two NARMS methodologies (FDA and USDA) were compared with standard culture (SC) techniques for recovery of EC. NARMS methods failed to detect EC in 58 caecal samples, 20 chicken breast or six whole broiler samples. EC was recovered from 1 of 38 (2·6%) and 2 of 38 (5·2%) preharvest spinal lesions (USDA and FDA method, respectively). In contrast, using the SC method, EC was recovered from 44 of 53 (83%) caecal samples, all 38 (100%) spinal lesions, 14 of 20 (70%) chicken breast samples, and all three spinal lesions identified in whole carcasses. Compared with other Enterococcus spp., EC isolates had a higher prevalence of resistance to macrolides. The NARMS methods significantly affected recovery of enterococcal species other than EC. When the postharvest FDA method was applied to preharvest caecal samples, isolates of Enterococcus faecium were preferentially recovered. All 11 E. faecium isolates were multidrug resistant, including resistance to penicillin, daptomycin and linezolid. These findings confirm that current methodologies may not accurately identify the amount and range of antimicrobial resistance of enterococci from chicken sources.
Significance and Impact of the Study
Enterococci are an important reservoir for antimicrobial resistance. This study demonstrates how current culture methods underreport resistance to macrolides in enterococci by selecting against strains of Enterococcus cecorum in pre‐ and postharvest chicken. Further, the application of postharvest surveillance methods to preharvest samples resulted in selective recovery of Enterococcus faecium over Enterococcus faecalis. Isolates of E. faecium recovered exhibited multidrug resistance including penicillin, daptomycin and linezolid resistance. These findings suggest that culture methodology significantly impacts the range and amount of antimicrobial resistance detected in enterococci isolated from chicken.
Significance and Impact of the Study: Enterococci are an important reservoir for antimicrobial resistance. This study demonstrates how current culture methods underreport resistance to macrolides in enterococci by selecting against strains of Enterococcus cecorum in pre‐ and postharvest chicken. Further, the application of postharvest surveillance methods to preharvest samples resulted in selective recovery of Enterococcus faecium over Enterococcus faecalis. Isolates of E. faecium recovered exhibited multidrug resistance including penicillin, daptomycin and linezolid resistance. These findings suggest that culture methodology significantly impacts the range and amount of antimicrobial resistance detected in enterococci isolated from chicken.
Enterococcus cecorum (EC) is the dominant enteric commensal of adult chickens and contributes to the gut consortia of many avian and mammalian species. While EC infection is an uncommon zoonosis, ...like other enterococcal species it can cause life-threating nosocomial infection in people. In contrast to other enterococci which are considered opportunistic pathogens, emerging pathogenic strains of EC cause outbreaks of musculoskeletal disease in broiler chickens. Typical morbidity and mortality is comparable to other important infectious diseases of poultry. In molecular epidemiologic studies, pathogenic EC strains were found to be genetically clonal. These findings suggested acquisition of specific virulence determinants by pathogenic EC. To identify divergent genomic features and acquired virulence determinants in pathogenic EC; comparative genomic analysis was performed on genomes of 3 pathogenic and 3 commensal strains of EC. Pathogenic isolates had smaller genomes with a higher GC content, and they demonstrated large regions of synteny compared to commensal isolates. A molecular phylogenetic analysis demonstrated sequence divergence in pathogenic EC genomes. At a threshold of 98% identity, 414 predicted proteins were identified that were highly conserved in pathogenic EC but not in commensal EC. Among these, divergent CRISPR-cas defense loci were observed. In commensal EC, the type IIA arrangement typical for enterococci was present; however, pathogenic EC had a type IC locus, which is novel in enterococci but commonly observed in streptococci. Potential mediators of virulence identified in this analysis included a polysaccharide capsular locus similar to that recently described for E. faecium, an epa-like locus, and cell wall associated proteins which may bind host extracellular matrix. This analysis identified specific genomic regions, coding sequences, and predicted proteins which may be related to the divergent evolution and increased virulence of emerging pathogenic strains of EC.
Facultative anaerobic enteric pathogens can utilize a diverse array of alternate electron acceptors to support anaerobic metabolism and thrive in the hypoxic conditions within the mammalian gut. ...Dimethyl sulfoxide (DMSO) is produced by methionine catabolism and can act as an alternate electron acceptor to support anaerobic respiration. The DMSO reductase complex consists of three subunits, DmsA, DmsB, and DmsC, and allows bacteria to grow anaerobically with DMSO as an electron acceptor. The genomes of nontyphoidal Salmonella enterica encode three putative
operons, but the impact of the apparent genetic redundancy in DMSO reduction on the fitness of nontyphoidal S. enterica during infection remains unknown. We hypothesized that DMSO reduction would be needed for S. enterica serotype Typhimurium to colonize the mammalian gut. We demonstrate that an
Typhimurium mutant with loss of function in all three putative DMSO reductases (Δ
) poorly colonizes the mammalian intestine when the microbiota is intact and when inflammation is absent. DMSO reduction enhances anaerobic growth through nonredundant contributions of two of the DMSO reductases. Furthermore, DMSO reduction influences virulence by increasing expression of the type 3 secretion system 2 and reducing expression of the type 3 secretion system 1. Collectively, our data demonstrate that the DMSO reductases of
Typhimurium are functionally nonredundant and suggest DMSO is a physiologically relevant electron acceptor that supports S. enterica fitness in the gut.
Enterococcus cecorum was initially identified as a harmless commensal of the gastrointestinal tract of chickens. However, over the past 15 yr, pathogenic strains of E. cecorum have become a ...significant cause of morbidity and mortality in broiler breeders, and repeated outbreaks occur, but an environmental reservoir for pathogenic E. cecorum has yet to be identified. Genetic analyses of E. cecorum demonstrate that strains with increased pathogenicity are genetically related and share several putative virulence genes. Pathogenic E. cecorum carry increased antimicrobial resistance compared to commensal strains. These pathogenic strains can be recovered from retail meat and may serve as a reservoir for further spread of antimicrobial resistance among other Enterococcus spp. This review presents the current understanding of the pathogenesis of E. cecorum and briefly discusses antimicrobial resistance in E. cecorum due to the role of Enterococcus spp. in nosocomial infections in people.
Enterococcal spondylitis (ES) is a disease of commercial broiler chickens, with a worldwide distribution. Symmetrical hind limb paralysis typical of ES results from infection of the free thoracic ...vertebra (FTV) by pathogenic strains of Enterococcus cecorum . To determine the pathogenesis of ES, birds with natural and experimental ES were studied over time. In natural disease, case birds (n = 150) from an affected farm and control birds (n = 100) from an unaffected farm were evaluated at weeks 1–6. In control birds, intestinal colonization by E. cecorum began at week 3. In case birds, E. cecorum was detected in intestine and spleen at week 1, followed by infection of the FTV beginning at week 3. E. cecorum isolates recovered from intestine, spleen, and FTV of case birds had matching genotypes, confirming that intestinal colonization with pathogenic strains precedes bacteremia and infection of the FTV. Clinical intestinal disease was not required for E. cecorum bacteremia. In 1- to 3-week-old case birds, pathogenic E. cecorum was observed within osteochondrosis dissecans (OCD) lesions in the FTV. To determine whether OCD of the FTV was a risk factor for ES, 214 birds were orally infected with E. cecorum, and the FTV was evaluated histologically at weeks 1–7. Birds without cartilage clefts of OCD in the FTV did not develop ES; while birds with OCD scores ≥3 were susceptible to lesion development. These findings suggest that intestinal colonization, bacteremia, and OCD of the FTV in early life are crucial to the pathogenesis of ES.
Enterococcus spp. (ENT) are frequently co-isolated with avian pathogenic E. coli (APEC) from poultry with colibacillosis, a leading cause of flock mortality. Although largely overlooked, ENT may play ...an active role in these infections. To assess the frequency of ENT co-isolation in colibacillosis, cultures were collected from birds with gross lesions of omphalitis, polyserositis, and septicaemia over a 3-year period from three turkey flocks and three broiler flocks. In birds diagnosed with colibacillosis based on gross findings and isolation of E. coli, ENT were co-isolated with APEC in 35.7% (n = 41/115) of colibacillosis mortality and 3.7% of total mortality (n = 41/1122). Co-isolated APEC and ENT pairs (n = 41) were further characterized using antimicrobial resistance phenotyping and in vitro co-culture assays. E. faecalis (EF) was the most commonly co-isolated species (68% n = 28/41) and tetracycline resistance was the resistance phenotype most commonly found among APEC (51% n = 21/41) and ENT (93% n = 38/41). Under iron-restricted conditions, EF enhanced APEC growth in a proximity-dependent manner and APEC grown in mixed culture with EF exhibited a significant growth and survival advantage (P ≤ 0.01). In an embryo lethality assay, APEC co-infection with EF resulted in decreased survival of broiler embryos compared to mono-infections (P ≤ 0.05). These data demonstrate that EF augmented APEC survival and growth under iron limiting conditions, possibly translating to the increased virulence of APEC in broiler embryos. Thus, ENT co-infections may be a previously unrecognized contributor to colibacillosis-related mortality. Further investigations into the mechanism of this interaction are warranted.
RESEARCH HIGHLIGHTS
Enterococcus is frequently co-isolated with avian pathogenic E. coli (APEC).
Enterococcus faecalis (EF) enhances survival of APEC in iron restricted conditions.
EF co-infection increases APEC virulence in broiler embryos.
Enterococcus cecorum was isolated from spondylitis lesions in broilers from two flocks in North Carolina that were experiencing increased mortality. Affected birds showed paresis and paralysis, ...clinical signs characteristic of enterococcal spondylitis (ES). Affected birds rested on their hocks and caudal abdomens with legs extended forward and were unable to stand or walk. Necropsy examination of affected birds revealed firm to hard inflammatory masses involving the vertebral bodies at the level of the free thoracic vertebra that bulged dorsally and compressed the spinal cord. When opened, lesions contained pale, tan to yellow caseonecrotic material. Microscopically, necrosis and fibrinoheterophilic spondylitis with intralesional gram-positive bacteria were seen. Heavy growth of E. cecorum recovered from vertebral lesions confirmed the diagnosis of ES. To investigate possible sources of the organism for one of the flocks bacterial cultures were made from the environment, water lines, mice trapped on the farm, cecal/cloacal swabs from one of the parent broiler breeder flocks, egg residue, hatching eggs, and the hatchery environment. Except for cecal/cloacal swabs from the breeders, E. cecorum was not isolated from any of these samples. When compared phenotypically and genotypically, cecal/cloacal isolates of E. cecorum from the breeders differed from isolates from spondylitis lesions in the broilers. The source of E. cecorum for the broiler flocks was not determined, but vertical transmission appears unlikely.
Alice F. Chang (1943-2021) True, Reiko; Fu, Michi; Suyemoto, Karen ...
The American psychologist,
01/2023, Letnik:
78, Številka:
1
Journal Article
Recenzirano
This article memorializes Alice F. Chang (1943-2021). Alice helped to create the Marana Community Mental Health Clinic, serving Indigenous, migrant, and indigent communities. She created a model ...licensure law for psychologists and continuing education criterion for licensure. Alice was a leader in psychological organizations and advocacy, serving on numerous APA boards and committees. She was passionate about the need to nurture Asian American women in psychology and founded the AAPA's Division on Women in 1995, a signature example of her mentoring and leadership that also paved the way for future AAPA divisions. (PsycInfo Database Record (c) 2023 APA, all rights reserved).
Previous research indicates that racial discrimination is associated with negative mental health outcomes among Asian Americans, with mixed findings related to generational status and the relation of ...racism to multiple mental health outcomes simultaneously. To test whether generational status moderates relation between racism-related stress (RRS) and depression as mediated by anxiety and interpersonal sensitivity (IS). Two hundred twenty-two Asian American adults from a public university completed a survey. Measures included the Asian American Racism-Related Stress Inventory, the Depression, Anxiety, and IS subscales of the Brief Symptom Inventory, and demographic questions. Although RRS was related to mental health for the whole sample, disaggregation showed positive relations for RRS and mental health variables only for first-generation participants and not for 1.5 or second-generation participants. Generational status moderated the relation between RRS and depression as mediated by anxiety and IS only for first-generation participants. Post hocs that collapsed one-and-a-half- and second-generation participants into 1 group showed positive relations for RRS and IS, and mediation analyses indicated that IS is a possible mediator. The relation between RRS and mental health outcomes in Asian Americans differs based on generational status. Generational status should be considered in future research looking at the effects of RRS on mental health.
PDF
