Skip to main content
Lippincott Open Access logoLink to Lippincott Open Access
. 2023 Aug 18;36(5):360–365. doi: 10.1097/QCO.0000000000000960

Resistance in Enteric Shigella and nontyphoidal Salmonella: emerging concepts

Chaojie Yang 1, Ying Xiang 1, Shaofu Qiu 1
PMCID: PMC10487366  PMID: 37594001

Abstract

Purpose of review

The emergence of globally resistant enteric Shigella and nontyphoidal Salmonella strains (NTS) has limited the selection of effective drugs, which has become a major challenge for the treatment of infections. The purpose of this review is to provide the current opinion on the antimicrobial-resistant enteric Shigella and nontyphoidal Salmonella.

Recent findings

Enteric Shigella and NTS are resistant to almost all classes of antimicrobials in recent years. Those with co-resistance to ciprofloxacin, azithromycin and ceftriaxone, the first-line antibiotics for the treatment of infectious diarrhoea have emerged worldwide. Some of them have caused interregional and international spread by travel, trade, MSM, and polluted water sources. Several strains have even developed resistance to colistin, the last-resort antibiotic used for treatment of multidrug-resistant Gram-negative bacteria infections.

Summary

The drug resistance of enteric Shigella and NTS is largely driven by the use of antibiotics and horizontal gene transfer of mobile genetic elements. These two species show various drug resistance patterns in different regions and serotypes. Hence treatment decisions for Shigella and Salmonella infections need to take into consideration prevalent antimicrobial drug resistance patterns. It is worth noting that the resistance genes such as blaCTX,mph, ermB, qnr and mcr, which can cause resistance to ciprofloxacin, cephalosporin, azithromycin and colistin are widespread because of transmission by IncFII, IncI1, IncI2 and IncB/O/K/Z plasmids. Therefore, continuous global monitoring of resistance in Shigella and Salmonella is imperative.

Keywords: antibiotic, drug resistance, nontyphoidal Salmonella, outbreak, Shigella

INTRODUCTION

Enteric Shigella and nontyphoidal Salmonella (NTS) are widely recognized as predominant bacterial pathogens responsible for foodborne illnesses and are regarded as a significant public health concern globally [1,2]. Although acute diarrhoea caused by Shigella and NTS can be unpleasant, these diseases are usually self-limiting, and symptoms usually resolve within a few days with appropriate fluid and electrolyte management. However, in vulnerable populations, including children under 5 years of age, elderly, malnourished and immunocompromised individuals, these diseases can be life threatening. The use of antibiotics is an important means to shorten duration of illness and reduce infectivity [1]. However, with the increasing use of antibiotics, resistance of Shigella and NTS to different antibiotics continues to emerge, and these bacteria show high rates of multidrug resistance globally [2,3]. 

Box 1.

Box 1

no caption available

DRIVERS OF BACTERIAL RESISTANCE

The development of bacterial resistance can occur in certain bacterial strains, and the utilization of antibiotics in medical and veterinary practice exerts selective pressure that expedites this phenomenon [3]. The transmission of resistance to humans can occur through the consumption of meat products from treated animals or food that has been cross-contaminated during processing or retail [4,5]. It has been confirmed that Salmonella drug resistance is largely driven by the use of antibiotics in food-producing animals in developed countries [6,7]. Additionally, the spread of resistance can occur through direct contact with animals or environmental pathways, such as water or wildlife [8,9].

In Shigella spp., drug resistance is mainly because of0 their adeptness to survive and replicate in the human gastrointestinal tract while incorporating exogenous genetic material, including antimicrobial resistance (AMR) genes on mobile genetic elements, from other Gram-negative bacteria [3,10]. In recent years, multiple reports have demonstrated the isolation of multidrug-resistant (MDR) Shigella spp. from untreated sewage or well water, indicating that they are likely to easily obtain various drug-resistant genes or plasmids from the environment [1113]. In China, one distinct MDR clone of Shigella sonnei with multiple resistant plasmids caused six waterborne shigellosis outbreaks from 2015 to 2020 [14]. Fang et al.[15] conducted genomic and equation model analysis of Shigella flexneri from 1920 to 2020 worldwide, showing that the consumption of antibiotics promoted drug resistance and that mobile genetic elements were important contributors to antibiotic resistance genes in S. flexneri isolates.

REGIONAL DIFFERENCES IN BACTERIAL RESISTANCE

Antibiotic resistance rates in Salmonella vary by country and are affected by antimicrobial usage practices among humans and animals, and geographical regional differences in Salmonella epidemiology and Salmonella serovars. Over the past few years, surveillance data have indicated a rise in the resistance rates in Salmonella isolates from poultry in the United States and Brazil and a decline in Canada and eastern Spain [8,1618]. In contrast to other countries, including the United States, China exhibits a notably elevated incidence of MDR Salmonella Enteritidis (S. Enteritidis) [19]. The proportions of MDR Salmonella significantly vary among different countries and sources. In Bangladesh, 94% of Salmonella strains isolated from broiler chickens exhibited multidrug resistance [20]. Drug sensitivity testing showed that 47.3% of NTS strains in Taiwan were MDR between 2017 and 2018 [21]. Furthermore, the emergence and widespread dissemination of a novel Salmonella Typhimurium (S. Typhimurium) sequence type (ST) 313 in sub-Saharan Africa has resulted in sepsis without accompanying gastroenteritis. Additionally, a highly drug-resistant sublineage of ST313 has been identified, characterized by a combination of multidrug resistance, extended-spectrum β-lactamase (ESBL) production, and resistance to azithromycin [22]. The rise in drug-resistant S. Typhimurium ST313 isolates can be attributed to the sustained use of antibiotics [23].

Antimicrobial resistance (AMR) patterns in Shigella spp. are varied in different regions of the world, which is closely related to the frequency of antibiotic use and the development level (Table 1). Shigella isolates from Africa have high resistance to trimethoprim/sulfamethoxazole, tetracycline and ampicillin, while their resistance to ciprofloxacin, azithromycin and third-generation cephalosporin antibiotics is low [2426]. In addition to the high resistance of Shigella isolates in Asia to tetracycline, ampicillin and other older antibiotics, it is concerning that the resistance to azithromycin, ciprofloxacin and ceftriaxone is already at a high level or shows an upward trend [2,27,28]. Whereas shigellosis is endemic in Asia and Africa, burdening mostly children younger than 5 years, in developed regions, such as Europe, the Americas and Australia, Shigella infections are more common among gay or bisexual men, people with HIV, and homeless people or travellers. Moreover, the proportion of sexually transmitted Shigella infections is very high. Their rates of multidrug resistance are higher than those of Shigella isolates with other modes of transmission, with gradually increasing resistance trends, mainly to ampicillin and trimethoprim, azithromycin, ceftriaxone and ciprofloxacin [29,30,31▪▪,32▪▪].

Table 1.

Resistance patterns of Shigella spp. and Salmonella spp. in different regions or serovar

Species Region or serovar Antibiotic with resistance Reference
Shigella spp. Africa Trimethoprim/sulfamethoxazole, Tetracycline, Ampicillin [2426]
Asia Tetracycline, Ampicillin, Chloramphenicol, Azithromycin, Ciprofloxacin, Ceftriaxone [2,27,28]
Europe, Americas, Australia Tetracycline, Ampicillin, Trimethoprim, Azithromycin, Ceftriaxone, Ciprofloxacin [29,30,31▪▪,32▪▪]
Salmonella spp. Typhimurium Ampicillin, Chloramphenicol, Streptomycin, Sulfonamides, Tetracycline [35]
Enteritidis Nalidixic acid, Ampicillin, Streptomyces, Cefoperazone [8,37,40]
1,4,[5],12:i:- Ampicillin, Streptomycin, Sulphamethoxazole, Tetracycline
Sulfaoxazole, Doxycycline
[41,42]
Infantis Nalidixic acid, Trimethoprim, Tetracycline, Ampicillin, Ciprofloxacin [5]
Albany Ampicillin, Chloramphenicol, Streptomycin, Sulfisoxazole, Tetracycline, Nalidixic acid [40]

Although resistance of Shigella spp. has certain regional differences, the spatiotemporal change in resistance is of a major concern. Initially, S. sonnei only developed resistance to some old antibiotics (such as tetracycline and ampicillin); however, a ciprofloxacin-resistant clone has later emerged in Asia [33]. Subsequently, a clone with multiresistance to azithromycin, ciprofloxacin, and third-generation cephalosporin emerged in 2014 and was transmitted among MSM in Europe and America during 2015 and 2022 [31▪▪,32▪▪,34]. In recent years, clones with multiresistance to azithromycin and ceftriaxone that frequently cause waterborne outbreaks have been found in Asia, some of which were even resistant to colistin [14].

SEROVAR DIFFERENCES OF BACTERIAL RESISTANCE

The AMR surveillance data for Salmonella show that serovar differences have the most impact on overall resistance trends [35] (Table 1). The predominant antibiotic resistance pattern observed in S. Typhimurium is ACSSuT (ampicillin, chloramphenicol, streptomycin, sulphonamides and tetracycline), which is attributed to the prevalence of phage type DT104 in S. Typhimurium [36]. Compared with other serovars, S. Enteritidis exhibited elevated resistance to nalidixic acid, with reported rates as high as 94.5% [37]. Medalla et al.[38] conducted a comparative analysis of the incidence of antimicrobial-resistant NTS infections in the United States during two distinct periods, 2004–2008 and 2015–2016, utilizing a Bayesian hierarchical model. The results of their study indicated a significant increase of 40% in the annual incidence of Salmonella infections with clinically important resistance, specifically to ampicillin or ceftriaxone, or insensitivity to ciprofloxacin. This increase is primarily attributed to a surge in reports of serotype 1,4,[5],12:i:- and serovar Enteritidis [38]. The variation in the resistance observed among poultry isolates from East Asia and the European Union could be primarily attributed to dissimilarities in the serovar profiles of the respective isolates [20,39,40]. Most recently, Salmonella 1,4,[5],12:i:- has emerged as a significant etiological agent of the NTS disease in both animals and humans on a global scale. Additionally, this serotype exhibited the highest prevalence of multidrug resistance among all Salmonella serotypes, with 89.6% reported in Guizhou, China [41,42].

There are also differences in drug resistance among Shigella serotypes. The F2a, F3a and F4s serotypes of S. flexneri have higher multidrug resistance rates than other serotypes [4345]. In addition, as S. sonnei is more easily spread than S. flexneri, the transmission rate of drug resistance gene elements is higher. Therefore, the multidrug resistance rate of S. sonnei is higher than that of S. flexneri, especially for antibiotics such as fluoroquinolones and trimethoprim/sulfamethoxazole [31▪▪,46].

MOLECULAR MECHANISMS OF BACTERIAL RESISTANCE

Resistance of Shigella spp. and Salmonella spp. to first-line and second-line antibiotics used in clinical treatment is of particular concern. Ceftriaxone and ciprofloxacin resistance has been increasingly reported in Shigella spp. and Salmonella spp. and multiple molecular mechanisms have already been described. Genes encoding ESBL such as blaTEM, blaSHV, blaCMY, blaCTX-M and blaOXA contribute to ceftriaxone resistance in Shigella spp. and Salmonella spp. [4749]. Ciprofloxacin resistance in these bacteria is primarily attributed to dual mutations in the gyrA gene and a singular mutation in the parC gene, with infrequent identification of mutations in the gyrB and parE genes [50]. Furthermore, the emergence of plasmid-mediated quinolone resistance and efflux pumps have been identified as contributing factors to the development of low-level resistance to quinolones and fluoroquinolones [51]. The qnr genes comprise five distinct families, each possessing a varying number of alleles, namely qnrA1-7, qnrS1-4, qnrB1-31, qnrC and qnrD. Among these, qnrA, qnrB and qnrS are frequently identified in Salmonella[52▪▪,53]. As there is an increasing incidence of resistance to ciprofloxacin and ceftriaxone, azithromycin is regarded as a last resort, Food and Drug Administration (FDA)-approved antimicrobial agent for the treatment of systemic infections, especially those caused by Shigella spp. and Salmonella spp. The mechanisms of azithromycin resistance vary among bacteria, and carrying macrolide-resistant genes is considered the main mechanism of resistance for Shigella spp. and NTS. The azithromycin resistance phenotype is often conferred by the erm(B) gene and/or the complete genetic structure IS26-mph(A)-mrx-mphR-IS6100 in NTS [54]. The genetic structures IS26-mph(A)-mrx(A)-mph(R)(A)-IS6100 and mph(E)-msr(E)-IS482-IS6 carrying macrolide-resistant genes were also found in Shigella[55]. It is worth noting that in recent years, the emergence of Shigella spp. and NTS strains resistant to colistin, mediated by a plasmid-borne colistin resistance gene mcr, have become prevalent in many countries [14,5658]. Additionally, Zhai et al.[59] recently found that AcrB and CpxR could target ATP and reactive oxygen species generation to potentiate antibacterial activity of colistin.

CARRIERS OF BACTERIAL RESISTANCE

The dissemination of MDR plasmids among Gram-negative bacteria is the major factor in the spread of AMR. Plasmids carrying multiple AMR genes in NTS are mainly of the IncI1 and IncHI2 types [49,60]. A conjugative IncC type plasmid simultaneously encoding resistance to ciprofloxacin, ceftriaxone and azithromycin in NTS was reported in 2021 [51]. A broad-host-range IncC plasmid and its integrative mobilizable Salmonella genomic island 1 (SGI1) counterpart contribute to the spread of medically important antibiotic resistance genes among Gram-negative pathogens [61]. The emergence of blaCTX-M-harbouring pESI plasmids was reported in clinical NTS in Germany [62]. A self-transferable IncA/C plasmid and a hybrid IncA/C-FIIs MDR plasmid were found to be the major vehicles for disseminating both mcr-3 and blaCTX-M55 genes among Salmonella strains [61].

Plasmids commonly carrying multiple AMR genes in Shigella spp. mainly include IncFII, IncI1, IncI2 and IncB/O/K/Z plasmids, which can carry the blaCTX-M-3, blaCTX-M-14, blaCTX-M-15, blaCTX-M-27, blaCTX-M-55, blaCTX-M-134, mphA, aac(3)-IId, dfrA17, aadA5, sul1 and mcr-1 genes [14,63]. In the last quarter of 2021, an outbreak of S. sonnei infection occurred that likely involved multiple European countries [31▪▪]. From this Shigella strain, researchers isolated an IncFII plasmid carrying not only the blaCTX-M-27 resistance gene but also multiple other resistance genes, such as mphA. Moreover, the S. sonnei strain causing waterborne outbreaks in China contains an IncB/O/K/Z plasmid, which carries both blaCTX-M-14 and mphA. Analysis shows that these plasmids not only promote the flow of MDR Shigella strains but can also spread between S. sonnei and S. flexneri, indicating a high risk of drug resistance spread [64].

CONCLUSION

In summary, antibiotic resistance exhibited by enteric Shigella and NTS presents a significant challenge to the efficacy of treatment. These bacteria are complex pathogens with multifactorial transmission, and significant variations in drug resistance have been observed across different serotypes, isolation sources, or regions. The horizontal transfer of MDR plasmids is a significant contributing factor to the dissemination of drug resistance. Therefore, ongoing global surveillance of enteric Shigella and NTS resistance is imperative.

Acknowledgements

None.

Financial support and sponsorship

This review was funded by the National Natural Science Foundation of China (Nos. 82173580, 82102435 and 82202538).

Conflicts of interest

There are no conflicts of interest.

Footnotes

C.Y. and Y.X. contributed equally to this review.

REFERENCES AND RECOMMENDED READING

Papers of particular interest, published within the annual period of review, have been highlighted as:

  • ▪ of special interest

  • ▪▪ of outstanding interest

REFERENCES

  • 1.Marchello CS, Birkhold M, Crump JA. Complications and mortality of nontyphoidal salmonella invasive disease: a global systematic review and meta-analysis. Lancet Infect Dis 2022; 22:692–705. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 2.Salleh MZ, Nik Zuraina NMN, Hajissa K, et al. Prevalence of multidrug-resistant and extended-spectrum beta-lactamase-producing Shigella species in Asia: a systematic review and meta-analysis. Antibiotics (Basel) 2022; 11:1653. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 3.Baker S, Scott TA. Antimicrobial-resistant Shigella: where do we go next? Nat Rev Microbiol 2023; 21:409–410. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 4.Huber L, Agunos A, Gow SP, et al. Reduction in antimicrobial use and resistance to Salmonella, Campylobacter, and Escherichia coli in broiler chickens, Canada. Emerg Infect Dis 2021; 27:2434–2444. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 5.Montone AMI, Cutarelli A, Peruzy MF, et al. Antimicrobial resistance and genomic characterization of Salmonella Infantis from different sources. Int J Mol Sci 2023; 24:5492. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 6.Bearson SMD. Salmonella in swine: prevalence, multidrug resistance, and vaccination strategies. Annu Rev Anim Biosci 2022; 10:373–393. [DOI] [PubMed] [Google Scholar]
  • 7.Yin X, M’Ikanatha NM, Nyirabahizi E, et al. Antimicrobial resistance in non-Typhoidal Salmonella from retail poultry meat by antibiotic usage-related production claims - United States. Int J Food Microbiol 2021; 342:109044. [DOI] [PubMed] [Google Scholar]
  • 8.Cho S, Hiott LM, House SL, et al. Analysis of Salmonella enterica isolated from a mixed-use watershed in Georgia, USA: antimicrobial resistance, serotype diversity, and genetic relatedness to human isolates. Appl Environ Microbiol 2022; 88:e0039322. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 9.Merkevičienė L, Butrimaitė-Ambrozevičienė C, Paškevičius G, et al. Serological variety and antimicrobial resistance in salmonella isolated from reptiles. Biology 2022; 11:836. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 10.Zhao J, Zhang C, Xu Y, et al. Intestinal toxicity and resistance gene threat assessment of multidrug-resistant Shigella: a novel biotype pollutant. Environ Pollut 2023; 316 (Pt 1):120551. [DOI] [PubMed] [Google Scholar]
  • 11.Machado EC, Freitas DL, Leal CD, et al. Antibiotic resistance profile of wastewater treatment plants in Brazil reveals different patterns of resistance and multi resistant bacteria in final effluents. Sci Total Environ 2023; 857 (Pt 1):159376. [DOI] [PubMed] [Google Scholar]
  • 12.Shin H, Kim Y, Raza S, et al. Dynamics of genotypic and phenotypic antibiotic resistance in a conventional wastewater treatment plant in 2 years. Front Microbiol 2022; 13:898339. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 13.Denku CY, Ambelu A, Mitike G. Enteric bacterial pathogens and their antibiotic-resistant patterns from the environmental sources in different regions of Ethiopia: a laboratory-based cross-sectional study. Health Sci Rep 2022; 5:e521. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 14▪.Qiu S, Liu K, Yang C, et al. A Shigella sonnei clone with extensive drug resistance associated with waterborne outbreaks in China. Nat Commun 2022; 13:7365. [DOI] [PMC free article] [PubMed] [Google Scholar]; One distinct Shigella sonnei clone with multidrug-resistance and multiple resistant plasmids caused six waterborne shigellosis outbreaks in China from 2015 to 2020.
  • 15▪.Fang GY, Mu XJ, Huang BW, et al. Monitoring longitudinal trends and assessment of the health risk of Shigella flexneri antimicrobial resistance. Environ Sci Technol 2023; 57:4971–4983. [DOI] [PubMed] [Google Scholar]; The consumption of antibiotics promoted the antibiotic resistance and the mobile genetic elements were important contributors to ARGs in S. flexneri isolates.
  • 16.Cortés V, Sevilla-Navarro S, García C, et al. Monitoring antimicrobial resistance trends in Salmonella spp. from poultry in Eastern Spain. Poult Sci 2022; 101:101832. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 17.Morasi RM, da Silva AZ, Nuñez KVM, et al. Overview of antimicrobial resistance and virulence factors in Salmonella spp. isolated in the last two decades from chicken in Brazil. Food Res Int 2022; 162 (Pt a):111955. [DOI] [PubMed] [Google Scholar]
  • 18.Pires J, Huisman F, Bonhoeffer S, et al. Multidrug resistance dynamics in Salmonella in food animals in the United States: An analysis of genomes from public databases. Microbiol Spectr 2021; 9:e0049521. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 19.Cao G, Zhao S, Kuang D, et al. Geography shapes the genomics and antimicrobial resistance of Salmonella enterica Serovar Enteritidis isolated from humans. Sci Rep 2023; 13:1331. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 20.Das T, Rana EA, Dutta A, et al. Antimicrobial resistance profiling and burden of resistance genes in zoonotic Salmonella isolated from broiler chicken. Vet Med Sci 2022; 8:237–244. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 21.Chiou CS, Hong YP, Wang YW, et al. Antimicrobial resistance and mechanisms of azithromycin resistance in nontyphoidal Salmonella isolates in Taiwan, 2017 to 2018. Microbiol Spectr 2023; 11:e0336422. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 22.Van Puyvelde S, Pickard D, Vandelannoote K, et al. An African Salmonella Typhimurium ST313 sublineage with extensive drug-resistance and signatures of host adaptation. Nat Commun 2019; 10:4280. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 23.Balasubramanian R, Im J, Lee JS, et al. The global burden and epidemiology of invasive nontyphoidal Salmonella infections. Hum Vaccines Immunother 2019; 15:1421–1426. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 24.Hlashwayo DF, Noormahomed EV, Bahule L, et al. Susceptibility antibiotic screening reveals high rates of multidrug resistance of Salmonella, Shigella and Campylobacter in HIV infected and uninfected patients from Mozambique. BMC Infect Dis 2023; 23:255. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 25.Kasumba IN, Badji H, Powell H, et al. Shigella in Africa: new insights from the vaccine impact on diarrhea in Africa (VIDA) Study. Clin Infect Dis 2023; 76: (76 Suppl 1): S66–s76. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 26.Dessale M, Mengistu G, Mengist HM. Prevalence, antimicrobial resistance pattern, and associated factors of Salmonella and Shigella among under five diarrheic children attending public health facilities in Debre Markos town, Northwest Ethiopia. Frontiers Public Health 2023; 11:1114223. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 27.Baharvand A, Molaeipour L, Alesaeidi S, et al. The increasing antimicrobial resistance of Shigella species among Iranian pediatrics: a systematic review and meta-analysis. Pathogens Global Health 2023; 1–12. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 28.Nisa I, Haroon M, Driessen A, et al. Antimicrobial resistance of Shigella flexneri in Pakistani pediatric population reveals an increased trend of third-generation cephalosporin resistance. Curr Microbiol 2022; 79:118. [DOI] [PubMed] [Google Scholar]
  • 29.O’Flanagan H, Siddiq M, Llewellyn C, et al. Antimicrobial resistance in sexually transmitted Shigella in men who have sex with men: a systematic review. Int J STD AIDS 2023; 34:374–384. [DOI] [PubMed] [Google Scholar]
  • 30.Tansarli GS, Long DR, Waalkes A, et al. Genomic reconstruction and directed interventions in a multidrug-resistant Shigellosis outbreak in Seattle, WA, USA: a genomic surveillance study. Lancet Infect Dis 2023; 23:740–750. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 31▪▪.Charles H, Prochazka M, Thorley K, et al. Outbreak Control Team. Outbreak of sexually transmitted, extensively drug-resistant Shigella sonnei in the UK, 2021-22: a descriptive epidemiological study. Lancet Infect Dis 2022; 22:1503–1510. [DOI] [PubMed] [Google Scholar]; This article described a sexually transmitted outbreak of extensively drug-resistant (XDR) Shigella sonnei in the UK during 2021-2022.
  • 32▪▪.Trivett H. Increase in extensively drug resistant Shigella sonnei in Europe. Lancet Microbe 2022; 3:e481. [DOI] [PubMed] [Google Scholar]; The spread of extensively drug-resistant S. sonnei in Europe has increased.
  • 33.Chung The H, Rabaa MA, Pham Thanh D, et al. South Asia as a reservoir for the global spread of ciprofloxacin-resistant Shigella sonnei: a cross-sectional study. PLoS Med 2016; 13:e1002055. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 34.Gaudreau C, Bernaquez I, Pilon PA, et al. Clinical and genomic investigation of an international ceftriaxone- and azithromycin-resistant Shigella sonnei cluster among men who have sex with men, Montréal, Canada 2017-2019. Microbiol Spectr 2022; 10:e0233721. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 35.Carroll LM, Piacenza N, Cheng RA, et al. A multidrug-resistant Salmonella enterica Typhimurium DT104 complex lineage circulating among humans and cattle in the USA lost the ability to produce pertussis-like toxin ArtAB. Microb Genom 2023; 9:10. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 36.Mellor KC, Petrovska L, Thomson NR, et al. Antimicrobial resistance diversity suggestive of distinct Salmonella Typhimurium sources or selective pressures in food-production animals. Frontiers Microbiol 2019; 10:708. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 37.Dai W, Zhang Y, Zhang J, et al. Analysis of antibiotic-induced drug resistance of Salmonella enteritidis and its biofilm formation mechanism. Bioengineered 2021; 12:10254–10263. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 38.Medalla F, Gu W, Friedman CR, et al. Increased incidence of antimicrobial-resistant nontyphoidal Salmonella Infections, United States 2004-2016. Emerg Infect Dis 2021; 27:1662–1672. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 39.Chen Z, Bai J, Zhang X, et al. Highly prevalent multidrug resistance and QRDR mutations in Salmonella isolated from chicken, pork and duck meat in Southern China. Int J Food Microbiol 2021; 340:109055. [DOI] [PubMed] [Google Scholar]
  • 40.Wei B, Shang K, Cha SY, et al. Clonal dissemination of Salmonella enterica serovar albany with concurrent resistance to ampicillin, chloramphenicol, streptomycin, sulfisoxazole, tetracycline, and nalidixic acid in broiler chicken in Korea. Poult Sci 2021; 100:101141. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 41▪.Plumb ID, Brown AC, Stokes EK, et al. Increased multidrug-resistant Salmonella enterica I Serotype 4,[5],12:i:- infections associated with Pork, United States, 2009-2018. Emerg Infect Dis 2023; 29:314–322. [DOI] [PMC free article] [PubMed] [Google Scholar]; The study found ASSuT-resistant Salmonella 4,[5],12:i:- increased from 1.1% of Salmonella infections during 2009-2013 to 2.6% during 2014–2018.
  • 42.Long L, You L, Wang D, et al. Highly prevalent MDR, frequently carrying virulence genes and antimicrobial resistance genes in Salmonella enterica serovar 4,[5],12:i:- isolates from Guizhou Province, China. PLoS One 2022; 17:e0266443. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 43.Thorley K, Charles H, Greig DR, et al. Emergence of extensively drug-resistant and multidrug-resistant Shigella flexneri serotype 2a associated with sexual transmission among gay, bisexual, and other men who have sex with men, in England: a descriptive epidemiological study. Lancet Infect Dis 2023; 23:732–739. [DOI] [PubMed] [Google Scholar]
  • 44.Liao YS, Liu YY, Lo YC, Chiou CS. Azithromycin-nonsusceptible Shigella flexneri 3a in men who have sex with men, Taiwan, 2015-2016. Emerg Infect Dis 2016; 23:345–346. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 45.Yang C, Li P, Zhang X, et al. Molecular characterization and analysis of high-level multidrug-resistance of Shigella flexneri serotype 4 s strains from China. Sci Rep 2016; 6:29124. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 46.Gaufin T, Blumenthal J, Ramirez-Sanchez C, et al. Antimicrobial-Resistant Shigella spp. in San Diego, California, USA, 2017-2020. Emerg Infect Dis 2022; 28:1110–1116. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 47.Chiu CH, Lee JJ, Wang MH, et al. Genetic analysis and plasmid-mediated bla(CMY-2) in Salmonella and Shigella and the Ceftriaxone Susceptibility regulated by the ISEcp-1 tnpA-bla(CMY-2)-blc-sugE. J Microbiol Immunol Infect 2021; 54:649–657. [DOI] [PubMed] [Google Scholar]
  • 48.M’Ikanatha NM, Yin X, Boktor SW, et al. Integrated surveillance for antimicrobial resistance in Salmonella from clinical and retail meat sources reveals genetically related isolates harboring quinolone- and ceftriaxone-resistant determinants. Open Forum Infect Dis 2021; 8:ofab213. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 49.Hiley L, Graham RMA, Jennison AV. Characterisation of IncI1 plasmids associated with change of phage type in isolates of Salmonella enterica serovar Typhimurium. BMC Microbiol 2021; 21:92. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 50.Zhang W, Zhou CL, Hu Y, et al. Dissemination of multiple drug-resistant Shigella flexneri 2a isolates among pediatric outpatients in Urumqi. China Foodborne Pathog Dis 2022; 19:522–528. [DOI] [PubMed] [Google Scholar]
  • 51.Chen K, Yang C, Chan EW, et al. Emergence of conjugative IncC type plasmid simultaneously encoding resistance to ciprofloxacin, ceftriaxone, and azithromycin in Salmonella. Antimicrob Agents Chemother 2021; 65:e0104621. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 52▪▪.Cuypers WL, Meysman P, Weill FX, et al. A global genomic analysis of Salmonella Concord reveals lineages with high antimicrobial resistance in Ethiopia. Nat Commun 2023; 14:3517. [DOI] [PMC free article] [PubMed] [Google Scholar]; The article provides a genomic overview of the population structure and antimicrobial resistance (AMR) of S. Concord by analysing genomes from 284 historical and contemporary isolates obtained between 1944 and 2022 across the globe.
  • 53.Yin X, Dudley EG, Pinto CN, et al. Fluoroquinolone sales in food animals and quinolone resistance in nontyphoidal Salmonella from retail meats: United States. J Glob Antimicrob Resist 2022; 29:163–167. [DOI] [PubMed] [Google Scholar]
  • 54.Xie M, Chen K, Chan EW, et al. Identification and genetic characterization of two conjugative plasmids that confer azithromycin resistance in Salmonella. Emerg Microb Infect 2022; 11:1049–1057. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 55.Nusrin S, Asad A, Hayat S, et al. Multiple mechanisms confer resistance to azithromycin in Shigella in Bangladesh: a comprehensive whole genome-based approach. Microbiol Spectr 2022; 10:e0074122. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 56.Li Y, Zhang Y, Chen M, et al. Plasmid-borne colistin resistance gene mcr-1 in a multidrug resistant Salmonella enterica serovar Typhimurium isolate from an infant with acute diarrhea in China. Int J Infect Dis 2021; 103:13–18. [DOI] [PubMed] [Google Scholar]
  • 57.Luk-In S, Chatsuwan T, Kueakulpattana N, et al. Occurrence of mcr-mediated colistin resistance in Salmonella clinical isolates in Thailand. Sci Rep 2021; 11:14170. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 58.Lima T, Loureiro D, Henriques A, et al. Occurrence and biological cost of mcr-1-carrying plasmids co-harbouring beta-lactamase resistance genes in zoonotic pathogens from intensive animal production. Antibiotics (Basel) 2022; 11:1356. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 59▪.Zhai YJ, Liu PY, Luo XW, et al. Analysis of regulatory mechanism of AcrB and CpxR on colistin susceptibility based on transcriptome and metabolome of Salmonella Typhimurium. Microbiol Spectr 2023; e0053023. [DOI] [PMC free article] [PubMed] [Google Scholar]; The study revealed several previously unknown regulatory mechanisms of AcrB and CpxR on the colistin susceptibility.
  • 60.Cuypers WL, Jacobs J, Wong V, et al. Fluoroquinolone resistance in Salmonella: insights by whole-genome sequencing. Microb Genom 2018; 4:e000195. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 61.Pons MC, Praud K, Da Re S, et al. Conjugative IncC plasmid entry triggers the SOS response and promotes effective transfer of the integrative antibiotic resistance element SGI1. Microbiol Spectr 2023; 11:e0220122. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 62.Pietsch M, Simon S, Meinen A, et al. Third generation cephalosporin resistance in clinical nontyphoidal Salmonella enterica in Germany and emergence of bla(CTX-M)-harbouring pESI plasmids. Microb Genom 2021; 7:000698. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 63.Lefèvre S, Njamkepo E, Feldman S, et al. Rapid emergence of extensively drug-resistant Shigella sonnei in France. Nat Commun 2023; 14:462. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 64▪.Mason LCE, Greig DR, Cowley LA, et al. The evolution and international spread of extensively drug resistant Shigella sonnei. Nat Commun 2023; 14:1983. [DOI] [PMC free article] [PubMed] [Google Scholar]; The article shows that the low fitness cost MDR plasmids have high risk of spread via horizontal gene transfer among different serotypes of Shigella.

Articles from Current Opinion in Infectious Diseases are provided here courtesy of Wolters Kluwer Health

RESOURCES