Prevalence, serotyping and antimicrobials resistance mechanism of Salmonella enterica isolated from clinical and environmental samples in Saudi Arabia

Characteristics of Nontyphoid Salmonella Isolated from Human, Environmental, Animal, and Food Samples in Burkina Faso: A Systematic Review and Meta-Analysis

Salmonella is one of the world's leading causes of zoonotic and foodborne illnesses. Recently, antimicrobial resistance (AMR) has become one of the most critical challenges to public health and food safety. Herein, we employed a meta-analysis to determine the pooled prevalence and spatiotemporal distribution of serovars and antimicrobial resistance in NTS in Burkina Faso. To find eligible articles, a comprehensive literature search of PubMed, African Journals Online, ScienceDirect, Google Scholar, and the gray literature (university libraries) in Burkina was conducted for the period from 2008 to 2020. Studies meeting the inclusion criteria were selected and assessed for risk of bias. To assess the temporal and spatial relationships between serotypes and resistant strains from humans, animals, food, and the environment, a random-effects statistical model meta-analysis was carried out using the Comprehensive Meta-Analysis Version 3.0 program. The NTS prevalence rates were 4.6% (95% CI: 3-7) and 20.1% (95% CI: 6.6-47.4) in humans and animals, respectively, and 16.8% (95% CI: 10.5-25.8) and 15.6% (95% CI: 8.2-27.5) in food and the environment, respectively. Most NTS serovars were S. Derby, reported both in food and animals, and S. Typhimurium, reported in humans, while S. Croft II, S. Jodpur II, and S. Kentucky were the most prevalent in the environment. NTS isolates were highly resistant to erythromycin, amoxicillin, cefixime, and cephalothin, with a pooled prevalence of multidrug resistance of 29% (95% CI: 14.5-49.5). The results of this review show a high diversity of Salmonella serotypes, as well as high antibiotic resistance in Salmonella isolates from animal, human, food, and environmental samples in Burkina, calling for a consolidated "One Health" approach to better understand the drivers of pathogen emergence, spread, and antimicrobial resistance, as well as the formulation of intervention measures needed to limit the risk associated with the disease.

Gastrointestinal Panel Performance for the Diagnosis of Acute Gastroenteritis in Pediatric Patients

BACKGROUND

Various methods are used to identify the causative organisms of acute gastroenteritis (AGE) in children. The gastrointestinal (GI) panel has the potential to detect up to 22 pathogens rapidly through the multiplex real-time PCR test. We studied the impact of the GI panel on clinical management in the pediatric population.

METHODS

A retrospective study was conducted to collect data on GI panel results and clinical details of inpatient children presenting with AGE at King Hamad University Hospital, Kingdom of Bahrain, over the course of one year.

RESULTS

One hundred nine samples were collected. The GI panel was positive in 96 samples (88.1%), with the majority detected in the toddler age group. Forty-one (42.7%) samples were positive for at least one organism. Salmonella was the most frequently encountered bacteria as a single isolate, 10/55 (18.2%), while enteropathogenic Escherichia coli was the most common co-infected organism, 16/41 (39%). Norovirus was the most common virus among the viruses. Bacterial detection peaked from July to October, while viral detection plateaued throughout the year. The GI panel and stool culture were positive for the same organism in 17 samples, versus one sample with a different organism. Sixty-two (56.9%) samples had a positive GI panel but negative stool cultures and stool analysis, and half of those detected viruses. The GI panel was positive in 86.2% of severely ill patients; the majority were bacteria. Bacterial detection was associated with a higher CRP compared to viruses.

CONCLUSION

The GI panel is an informative tool for detecting the causative pathogen of AGE in children. However, it can detect multiple organisms, indicating a possible carrier status, which points toward future studies.

Diversity and antimicrobial susceptibility patterns of clinical and environmental Salmonella enterica serovars in Western Saudi Arabia

The diverse environmental distribution of Salmonella makes it a global source of human gastrointestinal infections. This study aimed to detect Salmonella spp. and explore their diversity and antimicrobial susceptibility patterns in clinical and environmental samples. Pre-enrichment, selective enrichment, and selective plating techniques were adopted for the Salmonella detection whereas the API 20E test and Vitek Compact 2 system were used to confirm the identity of isolates. Salmonella serovars were subjected to molecular confirmation by 16S rDNA gene sequencing. Disc diffusion method and Vitek 2 Compact system determined the antibiotic susceptibility of Salmonella serovars. Multiple antibiotic resistance index (MARI) was calculated to explore whether Salmonella serovars originate from areas with heavy antibiotic usage. Results depicted low Salmonella prevalence in clinical and environmental samples (3.5%). The main detected serovars included Salmonella Typhimurium, S. enteritidis, S. Infantis, S. Newlands, S. Heidelberg, S. Indian, S. Reading, and S. paratyphi C. All the detected Salmonella serovars (27) exhibited multidrug resistance to three or more antimicrobial classes. The study concludes that the overall Salmonella serovars prevalence was found to be low in environmental and clinical samples of Western Saudi Arabia (Makkah and Jeddah). However, antimicrobial susceptibility patterns of human and environmental Salmonella serovars revealed that all isolates exhibited multidrug-resistance (MDR) patterns to frequently used antibiotics, which might reflect antibiotic overuse in clinical and veterinary medicine. It would be suitable to apply and enforce rules and regulations from the One Health approach, which aim to prevent antibiotic resistance infections, enhance food safety, and improve human and animal health, given that all Salmonella spp. detected in this investigation were exhibiting MDR patterns.

Prediction of key amino acids of Salmonella phage endolysin LysST-3 and detection of its mutants' activity

Salmonella Typhimurium, a zoonotic pathogen, causes systemic and localized infection. The emergence of drug-resistant S. Typhimurium has increased; treating bacterial infections remains challenging. Phage endolysins derived from phages have a broader spectrum of bacteriolysis and better bacteriolytic activity than phages, and are less likely to induce drug resistance than antibiotics. LysST-3, the endolysin of Salmonella phage ST-3, was chosen in our study for its high lytic activity, broad cleavage spectrum, excellent bioactivity, and moderate safety profile. LysST-3 is a promising antimicrobial agent for inhibiting the development of drug resistance in Salmonella. The aim of this study is to investigate the molecular characteristics of LysST-3 through the prediction of key amino acid sites of LysST-3 and detection of its mutants' activity. We investigated its lytic effect on Salmonella and identified its key amino acid sites of interaction with substrate. LysST-3 may be a Ca2+, Mg2+ - dependent metalloenzyme. Its concave structure of the bottom "gripper" was found to be an important part of its amino acid active site. We identified its key sites (29P, 30T, 86D, 88 L, and 89 V) for substrate binding and activity using amino acid-targeted mutagenesis. Alterations in these sites did not affect protein secondary structure, but led to a significant reduction in the cleavage activity of the mutant proteins. Our study provides a basis for phage endolysin modification to target drug-resistant bacteria. Identifying the key amino acid site of the endolysin LysST-3 provides theoretical support for the functional modification of the endolysin and the development of subsequent effective therapeutic solutions.

Genomic Landscape of Multidrug Resistance and Virulence in Enterococcus faecalis IRMC827A from a Long-Term Patient

We report on a highly virulent, multidrug-resistant strain of Enterococcus faecalis IRMC827A that was found colonizing a long-term male patient at a tertiary hospital in Khobar, Saudi Arabia. The E. faecalis IRMC827A strain carries several antimicrobial drug resistance genes and harbours mobile genetic elements such as Tn6009, which is an integrative conjugative element that can transfer resistance genes between bacteria and ISS1N via an insertion sequence. Whole-genome-sequencing-based antimicrobial susceptibility testing on strains from faecal samples revealed that the isolate E. faecalis IRMC827A is highly resistant to a variety of antibiotics, including tetracycline, doxycycline, minocycline, dalfopristin, virginiamycin, pristinamycin, chloramphenicol, streptomycin, clindamycin, lincomycin, trimethoprim, nalidixic acid and ciprofloxacin. The isolate IRMC827A carries several virulence factors that are significantly associated with adherence, biofilm formation, sortase-assembled pili, manganese uptake, antiphagocytosis, and spreading factor of multidrug resistance. The isolate also encompasses two mutations (G2576T and G2505A) in the 23S rRNA gene associated with linezolid resistance and three more mutations (gyrA p.S83Y, gyrA p.D759N and parC p.S80I) of the antimicrobial resistance phenotype. The findings through next-generation sequencing on the resistome, mobilome and virulome of the isolate in the study highlight the significance of monitoring multidrug-resistant E. faecalis colonization and infection in hospitalized patients. As multidrug-resistant E. faecalis is a serious pathogen, it is particularly difficult to treat and can cause fatal infections. It is important to have quick and accurate diagnostic tests for multidrug-resistant E. faecalis, to track the spread of multidrug-resistant E. faecalis in healthcare settings, and to improve targeted interventions to stop its spread. Further research is necessary to develop novel antibiotics and treatment strategies for multidrug-resistant E. faecalis infections.

Oxford nanopore technologies-a valuable tool to generate whole-genome sequencing data for in silico serotyping and the detection of genetic markers in Salmonella

Bacteria of the genus Salmonella pose a major risk to livestock, the food economy, and public health. Salmonella infections are one of the leading causes of food poisoning. The identification of serovars of Salmonella achieved by their diverse surface antigens is essential to gain information on their epidemiological context. Traditionally, slide agglutination has been used for serotyping. In recent years, whole-genome sequencing (WGS) followed by in silico serotyping has been established as an alternative method for serotyping and the detection of genetic markers for Salmonella. Until now, WGS data generated with Illumina sequencing are used to validate in silico serotyping methods. Oxford Nanopore Technologies (ONT) opens the possibility to sequence ultra-long reads and has frequently been used for bacterial sequencing. In this study, ONT sequencing data of 28 Salmonella strains of different serovars with epidemiological relevance in humans, food, and animals were taken to investigate the performance of the in silico serotyping tools SISTR and SeqSero2 compared to traditional slide agglutination tests. Moreover, the detection of genetic markers for resistance against antimicrobial agents, virulence, and plasmids was studied by comparing WGS data based on ONT with WGS data based on Illumina. Based on the ONT data from flow cell version R9.4.1, in silico serotyping achieved an accuracy of 96.4 and 92% for the tools SISTR and SeqSero2, respectively. Highly similar sets of genetic markers comparing both sequencing technologies were identified. Taking the ongoing improvement of basecalling and flow cells into account, ONT data can be used for Salmonella in silico serotyping and genetic marker detection.

Monitoring of Antimicrobial Resistance of Salmonella Serotypes Isolated from Humans in Northwest Italy, 2012-2021

Salmonella enterica is among the most common causes of foodborne outbreaks in humans in Europe. The global emergence of resistance to antimicrobials calls for close monitoring of the spread and prevalence of resistant Salmonella strains. In this study, we investigated the occurrence of antimicrobial resistance of Salmonella serotypes isolated from humans between 2012 and 2021 in Piedmont, northwest Italy. A total of 4814 Salmonella strains (168 serotypes) were tested against six classes of antimicrobials. Many strains (83.3%) showed resistance to at least one antibiotic: tetracycline (85.1%), ampicillin (79.2%), quinolones (47.4%), and gentamicin (28.4%). Between the first (2012-2016) and the second study period (2017-2021), a decrease in antimicrobial resistance was noted for tetracycline (from 92.4% to 75.3%), ampicillin (from 85.3% to 71.3%), quinolones (from 49.4% to 44.6%), and cefotaxime (from 34.8% to 4.0%). Many multidrug resistant Salmonella strains (43.6%) belonged to S. ser. Typhimurium, S. ser. Infantis, and S. ser. Typhimurium 1,4,[5],12:i:-. Overall, multidrug resistance decreased from 60.7% to 26.4%, indicating a reduction in the antimicrobial resistance of Salmonella strains in Piedmont and in Europe and demonstrating the effectiveness of the measures that were put in place to reduce antimicrobial resistance.

Occurrence of virulence factors and carbapenemase genes in Salmonella enterica serovar Enteritidis isolated from chicken meat and egg samples in Iraq

BACKGROUND

Food-borne infections mainly due to Salmonella enterica serovar Enteritidis (S. Enteritidis) are major concerns worldwide. S. Enteritidis isolates may serve as reservoirs for spreading antimicrobial drug resistance genes including carbapenemases. This study aimed to screen the occurrence of virulence factors, carbapenemases, and antibiotic resistance genes in S. Enteritidis isolated from chicken meat and eggs in Iraq.

RESULTS

In total, 1000 non-duplicated chicken meat and 1000 egg samples were collected during 2019-2020. Presumptive S. Enteritidis isolates were initially identified by standard bacteriology tests and then were confirmed using polymerase chain reaction (PCR). Carbapenem resistance was detected using the disk diffusion method. Virulence and carbapenemase genes were screened using the PCR method. In total, 100 (5.0%) S. Enteritidis isolates were identified from 2000 samples collected using phenotypic and molecular methods. These isolates were identified from 4.9% chicken meat (n = 49/1000) and 5.1% egg (n = 51/1000) samples, respectively. The most and the least susceptibility was found to gentamicin and ceftazidime antibiotics, respectively. The prevalence of different virulence factors were as follows: phoP/Q (40.0%), traT (30.0%), stn (22.0%), slyA (11.0%), and sopB (9.0%). Among 20 carbapenem-resistant S. Enteritidis isolates, the most predominant carbapenemase gene was bla_IMP (35.0%, n = 7), followed by bla_OXA-48-like (25.0%, n = 5), and bla_NDM (10.0%, n = 2), while the bla_KPC and bla_VIM genes were not detected. The coexistence of bla_IMP, bla_OXA-48-like, and bla_NDM genes was determined in two isolates. The prevalence of different antibiotic resistance genes were as follows: tetA (87.1%), tetB (87.1%), dfrA1 (77.6%), and sul1 (83.6%).

CONCLUSION

Considering the existence of carbapenem-resistant S. Enteritidis harboring different virulence and antibiotic resistance genes in chicken meat and egg samples, adherence to proper hygienic conditions should be considered.

Multi‑locus sequence and drug resistance analysis of Salmonella infection in children with diarrhea in Guangdong to identify the dominant ST and cause of antibiotic‑resistance

Multi-locus sequence typing (MLST) can be used to analyze the homology among the drug resistance gene cassettes in Salmonella and determine the prevalence. Information extracted using this technique can provide a theoretical basis for hospitals to devise protocols to control Salmonella infections. The aim of the present study was to investigate the possible association between drug resistance and integrons in clinical isolates of Salmonella from human fecal samples. Therefore, in the present study, 52 clinical fecal isolates of non-duplicate (i.e., not genome contamination) Salmonella were harvested from children with diarrhea and used for bacterial identification using biochemical tests, drug susceptibility analysis by antibiotic susceptibility testing and serotype identification using an agglutination assay. In total, seven Salmonella housekeeping genes (chorismate synthase, β sliding clamp of DNA polymerase III, uroporphyrinogen-III synthase, histidinol dehydrogenase, phosphoribosylaminoimidazole carboxylase catalytic subunit, 2-oxoglutarate dehydrogenase E1 component and homoserine dehydrogenase) were amplified and sequenced using MLST, before sequence alignment was performed against the Pub MLST database to determine the sequence-typed (ST) strains and construct genotypic evolutionary diagrams. Subsequently, the 52 Salmonella strains were subdivided into 11 serotypes and 11 sequence types. The dominant subtypes were found to be Salmonella typhimurium ST34 and ST19, which were diversely distributed. However, no new subtypes were found. Although the serotypes, including ST19, ST29, ST34, ST40, ST11, ST27, ST469, ST365, ST1499, ST413 and ST588, were closely associated with the MLST subtype, they did not correspond entirely. The detection rate of class I integrons was 38.46% (20/52), but no class II and III integrons were detected. The variable regions of three of 20 class I integrons were found to be amplified, whereas nine gene cassettes, including dihydrofolate reductase A12, open reading frame F, aminoglycoside-adenylyltransferase (aad)A2, aadA22, aadA23, aadA1, cadmium-translocating P-type ATPase 2, lincosamide and linF, were associated with drug resistance. These data suggest that Class I integrons are important factors underlying drug resistance in Salmonella, which may serve a role in the spread of drug resistance and warrant specific focus. In addition, MLST typing and serotyping should be applied cooperatively in epidemiological research.

Prevalence of Antimicrobial Resistance Genes in Salmonella Typhi: A Systematic Review and Meta-Analysis

Salmonella enterica serovar Typhi (S. Typhi) that has developed resistance to many antimicrobials poses a serious challenge to public health. Hence, this study aimed to systematically determine the prevalence of antimicrobial resistance (AMR) in S. Typhi isolated from the environment and humans as well as to ascertain the spread of the selected AMR genes in S. Typhi. This systematic review and meta-analysis were performed according to the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) guidelines, and the study protocol was registered with the International Prospective Register of Systematic Reviews (PROSPERO). A total of 2353 studies were retrieved from three databases, of which 42 studies fulfilled the selection criteria. The pooled prevalence of AMR S. Typhi (using a random-effect model) was estimated at 84.8% (95% CI; 77.3−90.2), with high heterogeneity (I2: 95.35%, p-value < 0.001). The high estimated prevalence indicates that control methods should be improved immediately to prevent the spread of AMR among S. Typhi internationally.

Antimicrobial resistance and genetic background of non-typhoidal Salmonella enterica strains isolated from human infections in São Paulo, Brazil (2000-2019)

Salmonella enterica causes Salmonellosis, an important infection in humans and other animals. The number of multidrug-resistant (MDR) phenotypes associated with Salmonella spp. isolates is increasing worldwide, causing public health concern. Here, we aim to characterize the antimicrobial-resistant phenotype of 789 non-typhoidal S. enterica strains isolated from human infections in the state of São Paulo, Brazil, along 20 years (2000-2019). Among the non-susceptible isolates, 31.55, 14.06, and 13.18% were resistant to aminoglycosides, tetracycline, and β-lactams, respectively. Moreover, 68 and 11 isolates were considered MDR and Extended Spectrum β-Lactamase (ESBL) producers, respectively, whereas one isolate was colistin-resistant. We selected four strains to obtain a draft of the Genome Sequence; one S. Infantis (ST32), one S. Enteritidis (ST11), one S. I 4,[5],12:i:- (ST19), and one S. Typhimurium (ST313). Among them, three presented at least one of the following antimicrobial resistance genes (AMR) linked to mobile DNA: bla_TEM-1B, dfrA1, tetA, sul1, floR, aac(6')-laa, and qnrE1. This is the first description of the plasmid-mediated quinolone resistance (PMQR) gene qnrE1 in a clinical isolate of S. I 4,[5],12:i:-. The S. Typhimurium is a colistin-resistant isolate, but did not harbor mcr genes, but it presented mutations within the mgrB, pmrB, and pmrC regions that might be linked to the colistin-resistant phenotype. The virulence pattern of the four isolates resembled the virulence pattern of the highly pathogenic S. Typhimurium UK-1 reference strain in assays involving the in vivo Galleria mellonella model. In conclusion, most isolates studied here are susceptible, but a small percentage present an MDR or ESBL-producer and pathogenic phenotype. Sequence analyses revealed plasmid-encoded AMR genes, such as β-lactam and fluoroquinolone resistance genes, indicating that these characteristics can be potentially disseminated among other bacterial strains.

Novel multiplex PCR assays for rapid identification of Salmonella serogroups B, C1, C2, D, E, S. enteritidis, and S. typhimurium

Foodborne illnesses caused by Salmonella represent a significant public health problem worldwide. The aim of this study was to establish multiplex PCR (mPCR) for the rapid identification of Salmonella serogroups B, C1, C2, D, and E as well as for the serovars enteritidis and typhimurium. Employing pan-genome analysis and PCR verification, B-rfbJ, C1-9679, C2-pimB, D-rfbJ, E-rfbC, and four genes (SE18636, SE16574, SE2599, and SE13329) were identified as specific target genes for Salmonella serogroups B, C1, C2, D, E, and S. enteritidis, respectively. Thereafter, three novel mPCR assays (one of 3-mPCR and two of 2-mPCR) were successfully developed to identify these bacteria based on the target genes and another S. typhimurium-specific STM4495 gene. The primers targeting C1-9679, C2-pimB, and E-rfbC genes specific to the serogroups C1, C2, and E, respectively, constituted a 3-mPCR, while the other two 2-mPCRs, respectively, consisting primers specific to serogroup D and S. enteritidis (D-rfbJ and SE16574), and serogroup B and S. typhimurium-specific primers (B-rfbJ and STM4495), were also designed. The specificity of each mPCR was further evaluated by using non-target strains. The detection limits of mPCRs were approximately 10³-10⁴ CFU mL^-1 in pure culture and 10⁴-10⁵ CFU g^-1 in spiked chicken meat. In addition, mPCR assays could correctly detect target Salmonella in food samples. These results suggest that specific targets could be mined efficiently through a pan-genome analysis tool, and the novel mPCR assays developed in this study offer a promising technique for rapid and accurate detection of five serogroups of Salmonella (B, C1, C2, D, and E) and two serovars (S. enteritidis and S. typhimurium).

Phenotypic characterization and genome analysis of a novel Salmonella Typhimurium phage having unique tail fiber genes

Salmonella enterica serovar Typhimurium is a foodborne pathogen causing occasional outbreaks of enteric infections in humans. Salmonella has one of the largest pools of temperate phages in its genome that possess evolutionary significance for pathogen. In this study, we characterized a novel temperate phage Salmonella phage BIS20 (BIS20) with unique tail fiber genes. It belongs to the subfamily Peduovirinae genus Eganvirus and infects Salmonella Typhimurium strain (SE-BS17; Acc. NO MZ503545) of poultry origin. Phage BIS20 was viable only at biological pH and temperature ranges (pH7 and 37 °C). Despite being temperate BIS20 significantly slowed down the growth of host strain for 24 h as compared to control (P < 0.009). Phage BIS20 features 29,477-base pair (bp) linear DNA genome with 53% GC content and encodes for 37 putative ORFs. These ORFs have mosaic arrangement as indicated by its ORF similarity to various phages and prophages in NCBI. Genome analysis indicates its similarity to Salmonella enterica serovar Senftenberg prophage (SEStP) sequence (Nucleotide similarity 87.7%) and Escherichia virus 186 (~ 82.4% nucleotide similarity). Capsid genes were conserved however those associated with tail fiber formation and assembly were unique to all members of genus Eganvirus. We found strong evidence of recombination hotspot in tail fiber gene. Our study identifies BIS20 as a new species of genus Eganvirus temperate phages as its maximum nucleotide similarity is 82.4% with any phage in NCBI. Our findings may contribute to understanding of origin of new temperate phages.

Overcoming Multidrug Resistance in Salmonella spp. Isolates Obtained From the Swine Food Chain by Using Essential Oils: An in vitro Study

Antimicrobial resistance (AMR) is a global concern, and new approaches are needed to circumvent animal and food-borne resistant pathogens. Among the new strategies, the combination of antibiotics with natural compounds such as essential oils (EOs) could be an alternative to challenge bacterial resistance. The present study evaluates the phenotypic and genotypic antibiotic resistance of 36 Salmonella enterica (16 S. Typhimurium, 3 monophasic variant S. Typhimurium, 8 S. Enteritidis, 6 S. Rissen, 1 S. Typhi, and 2 S. Derby) strains, isolated from the swine production chain. The isolates displayed phenotypic resistance to gentamicin, amikacin, tobramycin, and tetracycline, while the resistance genes most commonly detected were parC, catA, nfsB, nfsA, blaTEM, tetA, and tetB. Then 31/36 Salmonella isolates were chosen to evaluate resistance to tetracycline and Thymus vulgaris, Eugenia caryophyllata, and Corydothymus capitatus EOs by determining minimum inhibitory concentrations (MICs). Finally, the synergistic effect between tetracycline and each EOs was evaluated by the checkerboard method, calculating the fractional inhibitory concentration (FIC) index. Among the EOs, C. capitatus displayed the best bioactivity in terms of MICs, with the lowest values (0.31 and 0.625 μl/ml). On the contrary, the strains showed the ability to grow in the presence of the maximum concentration of tetracycline employed (256 μg/ml). While not displaying a real synergism according to the FIC index, the combination of tetracycline compounds and the three EOs resulted in a significant reduction in the MIC values to tetracycline (4 μg/ml), suggesting a restoration of the susceptibility to the antibiotic in Salmonella spp.

Genome Analysis and Therapeutic Evaluation of a Novel Lytic Bacteriophage of Salmonella Typhimurium: Suggestive of a New Genus in the Subfamily Vequintavirinae

Salmonella Typhimurium, a foodborne pathogen, is a major concern for food safety. Its MDR serovars of animal origin pose a serious threat to the human population. Phage therapy can be an alternative for the treatment of such MDR Salmonella serovars. In this study, we report on detailed genome analyses of a novel Salmonella phage (Salmonella-Phage-SSBI34) and evaluate its therapeutic potential. The phage was evaluated for latent time, burst size, host range, and bacterial growth reduction in liquid cultures. The phage stability was examined at various pH levels and temperatures. The genome analysis (141.095 Kb) indicated that its nucleotide sequence is novel, as it exhibited only 1-7% DNA coverage. The phage genome features 44% GC content, and 234 putative open reading frames were predicted. The genome was predicted to encode for 28 structural proteins and 40 enzymes related to nucleotide metabolism, DNA modification, and protein synthesis. Further, the genome features 11 tRNA genes for 10 different amino acids, indicating alternate codon usage, and hosts a unique hydrolase for bacterial lysis. This study provides new insights into the subfamily Vequintavirinae, of which SSBI34 may represent a new genus.

Molecular Epidemiology of Salmonella enterica in Poultry in South Africa Using the Farm-to-Fork Approach

The presence of the zoonotic pathogen Salmonella in the food supply chain poses a serious public health threat. This study describes the prevalence, susceptibility profiles, virulence patterns, and clonality of Salmonella from a poultry flock monitored over six weeks, using the farm-to-fork approach. Salmonella was isolated using selective media and confirmed to the genus and species level by real-time polymerase chain reaction (RT-PCR) of the invA and iroB genes, respectively. Antimicrobial susceptibility profiles were determined using Vitek-2 and the Kirby–Bauer disk diffusion method against a panel of 21 antibiotics recommended by the World Health Organisation Advisory Group on Integrated Surveillance of Antimicrobial Resistance (WHO-AGISAR). Selected virulence genes were identified by conventional PCR, and clonality was determined using enterobacterial repetitive intergenic consensus PCR (ERIC-PCR). Salmonella was present in 32.1% of the samples: on the farm (30.9%), at the abattoir (0.6%), and during house decontamination (0.6%). A total of 210 isolates contained the invA and iroB genes. Litter, faeces, and carcass rinsate isolates were classified as resistant to cefuroxime (45.2%), cefoxitin (1.9%), chloramphenicol (1.9%), nitrofurantoin (0.4%), pefloxacin (11.4%), and azithromycin (11%). Multidrug resistance (MDR) was observed among 3.8% of the isolates. All wastewater and 72.4% of carcass rinsate isolates were fully susceptible. All isolates harboured the misL, orfL, pipD, stn, spiC, hilA, and sopB virulence genes, while pefA, spvA, spvB, and spvC were absent. In addition, fliC was only present among the wastewater isolates. Various ERIC-PCR patterns were observed throughout the continuum with different subtypes, indicating the unrelated spread of Salmonella. This study concluded that poultry and the poultry environment serve as reservoirs for resistant and pathogenic Salmonella. However, there was no evidence of transmission along the farm-to-fork continuum.

Prevalence of Antibiotic Resistance in Salmonella Serotypes Concurrently Isolated from the Environment, Animals, and Humans in South Africa: A Systematic Review and Meta-Analysis

One of the main global concerns is the usage and spread of antibiotic resistant Salmonella serovars. The animals, humans, and environmental components interact and contribute to the rapid emergence and spread of antimicrobial resistance, directly or indirectly. Therefore, this study aimed to determine antibiotic resistance (AR) profiles of Salmonella serotypes isolated from the environment, animals, and humans in South Africa by a systematic review and meta-analysis. The preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines were followed to search four databases for studies published from 1980 to 2021, that reported the antibiotic resistance profiles of Salmonella serotypes isolated in South Africa. The AR was screened from 2930 Salmonella serotypes which were isolated from 6842 samples. The Western Cape province had high pooled prevalence estimates (PPE) of Salmonella isolates with AR profiles followed by North West, Gauteng, and Eastern Cape with 94.3%, 75.4%, 59.4%, and 46.2%, respectively. The high PPE and heterogeneity were observed from environmental samples [69.6 (95% CI: 41.7−88.3), Q = 303.643, I² = 98.353, Q-P = 0.045], animals [41.9 (95% CI: 18.5–69.5), Q = 637.355, I² = 98.745, Q-P = 0.577], as well as animals/environment [95.9 (95% CI: 5.4−100), Q = 55.253, I² = 96.380, Q-P = 0.300]. The majority of the salmonella isolates were resistant to sulphonamides (92.0%), enrofloxacin and erythromycin (89.3%), oxytetracycline (77.4%), imipenem (72.6%), tetracycline (67.4%), as well as trimethoprim (52.2%), among the environment, animals, and humans. The level of multidrug-resistance recorded for Salmonella isolates was 28.5% in this review. This study has highlighted the occurrence of AR by Salmonella isolates from animals, humans, and environmental samples in South Africa and this calls for a consolidated “One Health” approach for antimicrobial resistance epidemiological research, as well as the formulation of necessary intervention measures to prevent further spread.

Emerging Status of Multidrug-Resistant Bacteria and Fungi in the Arabian Peninsula

Simple Summary

The incidence and developing status of multidrug-resistant bacteria and fungi, as well as their related mortality, is reviewed by a systematic published literature search from nine countries in the Arabian Peninsula. In order to analyse the emerging status and mortality, a total of 382 research articles were selected from a comprehensive screening of 1705 papers. More than 850 deaths reported since 2010 in the Arabian Peninsula due to the infection of multidrug-resistant bacteria and fungi. Multidrug-resistant bacteria Acinetobacter baumannii, Mycobacterium tuberculosis, Staphylococcus aureus, and fungi Candida auris are the most prevalent and causing high deaths. To control these infections and associated deaths in the Arabian Peninsula, continuous preventive measures, accurate methods for early diagnosis of infection, active surveillance, constant monitoring, developing vaccines, eradicating multidrug resistance modulators, and data sharing among countries are required.

Abstract

We aimed to identify the prevalence and emerging status of multidrug-resistant bacteria and fungi and their associated mortality in nine countries in the Arabian Peninsula. Original research articles and case studies regarding multidrug-resistant bacteria and fungi in the Arabian Peninsula, published during the last 10 years, were retrieved from PubMed and Scopus. A total of 382 studies were included as per the inclusion and exclusion criteria, as well as the PRISMA guidelines, from a thorough screening of 1705 articles, in order to analyse the emerging status and mortality. The emerging nature of >120 multidrug-resistant (MDR) bacteria and fungi in the Arabian Peninsula is a serious concern that requires continuous monitoring and immediate preventive measures. More than 50% (n = 453) of multidrug-resistant, microbe-associated mortality (n = 871) in the Arabian Peninsula was due to MDR Acinetobacter baumannii, Mycobacterium tuberculosis and Staphylococcus aureus infection. Overall, a 16.51% mortality was reported among MDR-infected patients in the Arabian Peninsula from the 382 articles of this registered systematic review. MDR A. baumannii (5600 isolates) prevailed in all the nine countries of the Arabian Peninsula and was one of the fastest emerging MDR bacteria with the highest mortality (n = 210). A total of 13,087 Mycobacterium tuberculosis isolates were reported in the region. Candida auris (580 strains) is the most prevalent among the MDR fungal pathogen in the Arabian Peninsula, having caused 54 mortalities. Active surveillance, constant monitoring, the development of a candidate vaccine, an early diagnosis of MDR infection, the elimination of multidrug resistance modulators and uninterrupted preventive measures with enhanced data sharing are mandatory to control MDR infection and associated diseases of the Arabian Peninsula. Accurate and rapid detection methods are needed to differentiate MDR strain from other strains of the species. This review summarises the logical relation, prevalence, emerging status and associated mortality of MDR microbes in the Arabian Peninsula.

Antimicrobial resistance patterns, virulence gene profiles, and genetic diversity of Salmonella enterica serotype Enteritidis isolated from patients with gastroenteritis in various Iranian cities

Objectives

This study aimed to evaluate antibiotic resistance profiles and presence of virulence genes among Salmonella enterica serovar Enteritidis (S. Enteritidis) isolated from patients with gastroenteritis in various regions of Iran. Moreover, genetic relatedness among the strains was assessed by pulsed-field gel electrophoresis (PFGE).

Materials and Methods

From April through September 2017, 59 Salmonella strains were isolated from 2116 stool samples. Of these strains, 27 S. Enteritidis were recovered. These strains were subjected to disk diffusion tests, polymerase chain reaction (PCR) for detection of virulence genes (invA, hilA, pefA, rck, stn, ssrA, ssaR, sefA, spvC, sipA, sipC, sopB, sopE, and sopE2), and PFGE.

Results

High prevalence of resistance towards cefuroxime (n = 20, 74.1%) and ciprofloxacin (n = 13, 48.2%) were demonstrated. All tested strains possessed invA, hilA, sefA, sipA, sopB, and sopE. The least prevalent virulence gene was rck (n = 6; 22.2%). Based on combinations of virulence genes, 12 virulotypes were observed. The most common virulotype was VP2 (n = 12; 44.4%), harboring all of the virulence genes except for rck. PFGE typing showed only two distinct fingerprints among tested strains. Each fingerprint had completely different virulotypes. Notably, VP4 (harboring all genes except for rck and spvC) was only presented in pulsotype A, while VP2 was confined to pulsotype B.

Conclusion

S. Enteritidis strains were derived from a limited number of clones, suggesting that it is highly homogenous. Future works should consider combinations of other genotyping methods together with larger sample sizes from more diverse sources.

Antimicrobial Resistance Profiling of Biofilm Forming Non Typhoidal Salmonella enterica Isolates from Poultry and Its Associated Food Products from Pakistan

Salmonellosis caused by non-typhoidal Salmonella enterica from poultry products is a major public health concern worldwide. This study aimed at estimating the pathogenicity and antimicrobial resistance in S. enterica isolates obtained from poultry birds and their food products from different areas of Pakistan. In total, 95/370 (25.67%) samples from poultry droppings, organs, eggs, and meat were positive for Salmonella. The isolates were further identified through multiplex PCR (mPCR) as Salmonella Typhimurium 14 (14.7%), Salmonella Enteritidis 12 (12.6%), and other Salmonella spp. 69 (72.6%). The phenotypic virulence properties of 95 Salmonella isolates exhibited swimming and/or swarming motility 95 (100%), DNA degrading activity 93 (97.8%), hemolytic activity 92 (96.8%), lipase activity 87 (91.6%), and protease activity 86 (90.5%). The sopE virulence gene known for conferring zoonotic potential was detected in S. Typhimurium (92.8%), S. Enteritidis (100%), and other Salmonella spp. (69.5%). The isolates were further tested against 23 antibiotics (from 10 different antimicrobial groups) and were found resistant against fifteen to twenty-one antibiotics. All isolates showed multiple drug resistance and were found to exhibit a high multiple antibiotic-resistant (MAR) index of 0.62 to 0.91. The strong biofilm formation at 37 °C reflected their potential adherence to intestinal surfaces. There was a significant correlation between antimicrobial resistance and the biofilm formation potential of isolates. The resistance determinant genes found among the isolated strains were bla_TEM-1 (59.3%), bla_OxA-1 (18%), bla_PSE-1 (9.5%), bla_CMY-2 (43%), and ampC (8.3%). The detection of zoonotic potential MDR Salmonella in poultry and its associated food products carrying cephalosporin and quinolone resistance genes presents a major threat to the poultry industry and public health.

Antibiotic resistome of Salmonella typhi: molecular determinants for the emergence of drug resistance

Resistome is a cluster of microbial genes encoding proteins with necessary functions to resist the action of antibiotics. Resistome governs essential and separate biological functions to develop resistance against antibiotics. The widespread clinical and nonclinical uses of antibiotics over the years have combined to select antibiotic-resistant determinants and develop resistome in bacteria. At present, the emergence of drug resistance because of resistome is a significant problem faced by clinicians for the treatment of Salmonella infection. Antibiotic resistome is a dynamic and ever-expanding component in Salmonella. The foundation of resistome in Salmonella is laid long before; therefore, the antibiotic resistome of Salmonella is reviewed, discussed, and summarized. We have searched the literature using PubMed, MEDLINE, and Google Scholar with related key terms (resistome, Salmonella, antibiotics, drug resistance) and prepared this review. In this review, we summarize the status of resistance against antibiotics in S. typhi, highlight the seminal work in the resistome of S. typhi and the genes involved in the antibiotic resistance, and discuss the various methods to identify S. typhi resistome for the proactive identification of this infection and quick diagnosis of the disease.

Highlights Regarding the Use of Metallic Nanoparticles against Pathogens Considered a Priority by the World Health Organization

The indiscriminate use of antibiotics has facilitated the growing resistance of bacteria, and this has become a serious public health problem worldwide. Several microorganisms are still resistant to multiple antibiotics and are particularly dangerous in the hospital and nursing home environment, and to patients whose care requires devices, such as ventilators and intravenous catheters. A list of twelve pathogenic genera, which especially included bacteria that were not affected by different antibiotics, was released by the World Health Organization (WHO) in 2017, and the research and development of new antibiotics against these genera has been considered a priority. The nanotechnology is a tool that offers an effective platform for altering the physicalchemical properties of different materials, thereby enabling the development of several biomedical applications. Owing to their large surface area and high reactivity, metallic particles on the nanometric scale have remarkable physical, chemical, and biological properties. Nanoparticles with sizes between 1 and 100 nm have several applications, mainly as new antimicrobial agents for the control of microorganisms. In the present review, more than 200 reports of various metallic nanoparticles, especially those containing copper, gold, platinum, silver, titanium, and zinc were analyzed with regard to their anti-bacterial activity. However, of these 200 studies, only 42 reported about trials conducted against the resistant bacteria considered a priority by the WHO. All studies are in the initial stage, and none are in the clinical phase of research.

Immunogenicity and duration of immunity of the polyvalent vaccine against chicken salmonellosis

Poultry salmonellosis causes serious economic damage and must be prevented by disinfection, zoohygienic measures or by vaccination. To develop a new polyvalent vaccine against poultry salmonellosis, we used bacterial strains of Salmonella enteritidis, S. typhimurium and S. gallinarum. Antigenic and immunogenic efficacy of the vaccine was tested on specific-pathogen free chickens, which were divided into five groups of 10 birds in each group and were vaccinated intramuscularly at 8 and 12 weeks: group A (non-immunized control), group B (S. enteritidis mono-vaccine), group C (S. typhimurium mono-vaccine), group D (S. gallinarum mono-vaccine) and group E (trivalent vaccine Polimun Salmo). None of the immunized birds showed such adverse reactions as abnormal behaviour, mortality or signs of anorexia, depression or diarrhea. Two weeks after the revaccination, 5 birds in each group were challenged by watering 3 cm3 of working suspensions of S. gallinarum, S. typhimurium and S. enteritidis control strains at a concentration of 1 × 109 CFU. 72 h after the challenge, faeces were collected from all chickens in each group to identify Salmonella excretion with faeces, and the chickens were euthanized. Significant protection against the virulent challenge was observed in all immunized groups based on mortality and post-mortem lesions compared with the non-immunized control group. Blood samples were selected weekly from 5 chickens of each group for 184 days. The antigenic efficacy of the vaccines was studied by reaction of haemagglutination in the obtained serum. The potent antigen-specific response to lymphocyte activation found in all immunized groups indicated the induction of immune responses. Overall, the results showed that persistent immunity is formed in 4 weeks after the revaccination and lasts for a productive period. Immune response of chickens on day 184 after vaccination with Polimun Salmo was 1: 647, indicating that the developed polyvalent vaccine against common serovars of S. enterica in poultry is effective and immunogenic and can be further used in field studies.

Characterization of non-typhoidal Salmonella from poultry in Punjab, India

Present study was done to determine the prevalence, virulence and antimicrobial spectrum of identified serotypes. A total of 693 samples, comprising 585 poultry fecal samples (420 from layer, 120 from broiler and 45 from backyard poultry), 54 each poultry feed and farm water were collected from 31 poultry farms of three districts of Punjab. A total of 6 Salmonella isolates were obtained from these samples. Out of 585 fecal samples, 6 (1.02%) were positive for Salmonella. Out of 31 farms, 2 (6.45%) farms were positive for Salmonella. Out of 6 Salmonella isolates, four isolates from one farm were serotype Salmonella IIIa, 35: z24: z23 and two Salmonella isolates from another farm were untypable and also carried spvC gene. Isolates showed resistance to gentamicin (2/6, 33.3%), co-trimoxazole (1/6, 16.7%). Antibiotics ampicillin, tetracycline, ciprofloxacin, chloramphenicol and enrofloxacin were effective against all the isolates. On PFGE analysis, four isolates from one farm were clustered in two clusters and two isolates from other farm were similar and clustered together. Based on the results we can say that drug resistant Salmonella is present in poultry flock in Punjab.

Molecular characterization of antimicrobial resistance and enterobacterial repetitive intergenic consensus-PCR as a molecular typing tool for Salmonella spp. isolated from poultry and humans

Background and Aim:

Salmonella spp. are one of the most important food-borne pathogens in the world, emerging as a major public health concern. Moreover, multidrug-resistant (MDR) strains have been isolated from salmonellosis outbreaks, which compromise its treatment success. This study was conducted to characterize the phenotypic and genotypic antibiotic resistance profile of Salmonella strains isolated from broilers and humans from the regions of Tolima and Santander (Colombia).

Materials and Methods:

Salmonella spp. strains (n=49) were confirmed through molecular detection by amplification of the invA gene. Phenotypic antibiotic resistance was determined by the automated method and the agar diffusion method, and the presence of resistance genes was evaluated by PCR. Genotypic characterization was conducted using the enterobacterial repetitive intergenic consensus (ERIC)-PCR method, from which a dendrogram was generated and the possible phylogenetic relationships were established.

Results:

Salmonella isolates were classified as MDR strains exhibiting resistance to four antibiotic classes, penicillins, aminoglycosides, sulfonamides, and cephalosporins, and the human strains were resistant to gentamicin. At the genotypic level, the isolates contained the genes bla_CMY2, bla_CTX-M, bla_PSE-1, bla_TEM, aadA1, srtB, dfrA1, sul2, and floR. The genotyping results obtained by ERIC-PCR allowed the grouping of strains according to the source of isolation.

Conclusion:

The Salmonella spp. strains exhibited resistance to multiple antibiotics, as well as multiple genes associated with them, and the ERIC-PCR method was a technique that was helpful in generating clusters with biological significance.

What is Behind Salmonella? Unusual Presentation in Two Pediatric Cases

Salmonella infection is an international public health concern. Salmonella organisms are Gram-negative bacilli that belong to the family Enterobacteriaceae, and more than 2500 Salmonella serovars have been described.

The most common clinical presentations of Salmonella infection are gastroenteritis, bacteremia, enteric fever, and chronic carrier state. Other rare extraintestinal infections include cellulitis, urinary tract infection, pneumonia, endocarditis, meningitis, brain abscess, and osteomyelitis.

Salmonella species resistant to first-line treatment such as ampicillin, chloramphenicol, and trimethoprim-sulfamethoxazole are referred to as multi-drug resistant. In recent years, extensively drug-resistant (XDR) Salmonella have appeared in Pakistan; XDR strains are resistant to multiple antibiotics, including first-line antibiotics, fluoroquinolones, and third-generation cephalosporins.

We report two interesting pediatric cases who presented with uncommon Salmonella infection. The first case is a child diagnosed with XDR typhoid fever in a country where the strain is not endemic. The second case is a child who presented with a Salmonella urinary tract infection who is otherwise immunocompetent and has no apparent underlying structural abnormalities of the urinary tract.

Occurrence of multidrug-resistant Salmonella in cattle carcass and contact surfaces in Kwata slaughterhouse, Awka, Anambra State, Nigeria

Background and Aim: Contamination of meat with Salmonella could result in food-borne disease outbreaks among the consumers. However, there is a dearth of data assessing the presence of Salmonella in beef in Anambra State. Therefore, this study determined the prevalence and antimicrobial susceptibility of Salmonella in beef and slaughter/processing facilities in Kwata slaughterhouse. Materials and Methods: Swab samples (200) randomly collected were cultured for the isolation of Salmonella and the isolates subjected to antimicrobial susceptibility test. Data obtained were analyzed using t-test and analysis of variance with p< 0.05 considered statistically significant. Results: Of the 200 samples cultured, 33.5% (67/200) yielded Salmonella isolates. The mean Salmonella load (colony-forming unit [CFU]/cm2) for different contact surfaces (before and after contact with carcasses) was as follows: Slaughter floor, 1.1×1010±1.1×106a and 1.0×1010±1.1×106b; display table, 1.1×1010±11.1×106a and 1.0×1010±1.1×106b; washing bucket 1.01×1010±1.0×106a and 0.8×1010±0.1×106b; knife, 1.1×1010±1.10×106a and 1×1010±1.0×106b; boot, 1.1×1010±1.0×106a and 1.0×1010±1.10×106b; file, 1.1×1010±1.0×106a and 1.0×1010±0.1×106b; and wheelbarrow, 1.1×1010±1.0×106a and 1.01×1010±0.11×106b. Salmonella counts decreased significantly (p<0.05) in the presented order from slaughter floor to wheelbarrow after contact with carcasses. On the other hand, there was a significant (p<0.05) increase in washing water Salmonella counts before and after (0.7×1010±0.10×106a and 1.0×1010±1.0×106b CFU/100 ml) carcasses wash. To each of the antimicrobials tested, the percentage of the 67 isolates found resistant was as follows: ciprofloxacin, 25.4%; ofloxacin, 27%; ceftriaxone, 35.8%; amoxicillin/clavulanic acid, 88.1%; chloramphenicol, 59.7%; gentamicin, 34.3%; streptomycin, 49.3%; nalidixic acid, 49.3%; trimethoprim/sulfamethoxazole, 76%; nitrofurantoin, 89.6%; and ampicillin, 100%. Conclusion: Antimicrobial-resistant Salmonella were isolated from beef and slaughter/processing facilities in Anambra State. This underscores the need for a coordinated one health approach for the improvement of hygienic standard during slaughter/processing in the slaughterhouse surveyed, to limit meat contamination and hence safeguard human health.

Pattern of increased antimicrobial resistance of Salmonella isolates in the Eastern Province of KSA

OBJECTIVES

The antimicrobial resistance of Salmonella species is increasing worldwide. This study was conducted to determine the pattern of antimicrobial susceptibility of Salmonella species in a tertiary hospital from 2011 to 2018.

METHODS

In this retrospective study, the medical records of all patients with Salmonella infections were reviewed. The clinical, demographic, and microbiological data of the selected patients were analysed.

RESULTS

A total of 752 patients were included. The resistance of Salmonella species to antimicrobial drugs increased from 24.6% in 2011 to 37.8% in 2018 (p = 0.002). By 2018 all Salmonella isolates were completely resistant to cefalotin, cefuroxime, and cefoxitin, while we found some susceptibility to other cephalosporins and ciprofloxacin. The most commonly isolated Salmonella serogroups were groups D (36.5%), C (23.5%), and B (11.7%).

CONCLUSIONS

The incidence of resistance of Salmonella to antibiotics is on the rise. The results of this study highlight the need for an active monitoring system of antibiotic usage in humans and domestic animals.

Identification of Salmonella Bredeney Resistant to Third-Generation Cephalosporins in Saudi Arabia

The rapidly increasing prevalence and spread of antibiotic-resistant Salmonella worldwide have become a thorny problem that poses a serious threat to human health. It is speculated that antibiotic abuse, frequent traveling, and mass gatherings accelerate this threat. To explore this hypothesis, we investigated 13 Salmonella isolates from Medina, Saudi Arabia and 15 from China as the control group using typical methods of serotype identification, antibiotic resistance tests, pulsed-field gel electrophoresis (PFGE), and multi-locus sequence typing (MLST). Our results indicated that the isolates from China showed greater serotype diversity and a higher antimicrobial resistance rate, which was consistent with results from other studies in China. In contrast, the Saudi Arabian isolates were mainly identified as Serovar Bredeney and were resistant to a limited number of antibiotics. Interestingly, two of the Bredeney isolates was resistant to third-generation cephalosporins but sensitive to all other tested antibiotics. To confirm the results and understand the underlying molecular mechanisms of these isolates, whole-genome sequencing (WGS) was performed. We discovered that several cephalosporin resistance-associated genes were shared with other strains, but one gene (LEN-23) was unique. Therefore, to the best of our knowledge, we concluded that this study is the first to report the emergence of Salmonella Bredeney resistant to third-generation cephalosporins in Saudi Arabia.

Antimicrobial resistance and genetic diversity of Salmonella enterica from eggs

Salmonella enterica is a common foodborne pathogen responsible for major global health problems such as paratyphoid fever and gastroenteritis. Here, we report the prevalence, antibiotic resistance phenotypes, serotypes, and molecular subtyping of Salmonella isolated from eggs in Guangdong, China. Out of 1,000 egg samples, 54 (5.40%) were positive. S. Enteritidis made up the largest proportion of samples with 11 serotypes. Antimicrobial susceptibility test indicated that most strains were resistant to β-lactam, aminoglycoside, and tetracycline antibiotics (27.00%-40.00%). There were 37 STs based on MLST typing. MLST and ERIC-PCR classified 54 isolates into three and five clusters, respectively, which revealed the genetic relatedness and diversity. In conclusion, frequent monitoring of eggs for Salmonella, antibiotic resistance profiles and genetic diversity is essential for improving food safety.

S. Enteritidis and S. Typhimurium Harboring SPI-1 and SPI-2 Are the Predominant Serotypes Associated With Human Salmonellosis in Saudi Arabia

Non-typhoidal Salmonella (NTS) strains are Gram negative bacterial pathogens that are associated with foodborne illness worldwide. During the process of infection, Salmonella uses two molecular injectisomes known as Type 3 Secretion Systems (T3SS) to secrete virulence factors that are encoded by Salmonella Pathogenicity Island-1 (SPI-1) and SPI-2 into host cells. These secretion systems play a major role in virulence, as shown in various animal models, but little is known about their role in human infections. In Saudi Arabia, NTS strains frequently cause human infections but data regarding these pathogenic strains is fairly limited. The aim of this study was to characterize Salmonella human clinical isolates in Riyadh, Saudi Arabia, by determining their serotype, testing for the presence of SPI-1 and SPI-2 genes and to determine the antibiotic resistance profiles of these strains. Using the rapid Check and Trace Salmonella^™ (CTS) system our results demonstrate that S. Enteritidis and S. Typhimurium were the predominant serovars, followed by S. Livingstone, S. Kentucky and S. Poona among a list of 36 serovars reported for the first time in the country. In addition, SPI-1 genes were detected in 99% of the isolates, while the sifA gene (SPI-2) was not detected in 13.5% of the isolates. These results suggest that both the SPI-1 and SPI-2 virulence determinants are important for human infection. Moreover, we report the presence of a Multi-Drug (MDR) carbapenem resistant S. Kentucky isolate harboring the bla_OXA−48 gene not reported previously in Saudi Arabia.

Invasive Salmonella infections among children in Bintulu, Sarawak, Malaysian Borneo: a 6-year retrospective review

Background

Invasive Salmonella infections result in significant morbidity and mortality in developing countries. In Asia, typhoid and paratyphoid fever are reported to be the major invasive Salmonella infections, while invasive non-typhoidal Salmonella (iNTS) infections are believed to be uncommon. Data from Sarawak, in Malaysian Borneo, are limited.

Methods

A retrospective study identifying all children aged < 15 years with invasive Salmonella infections from 2011 to 2016 was conducted in Bintulu Hospital in Sarawak. Population incidences, clinical and bacterial characteristics were examined.

Results

Forty-four patients were identified during the 6-year study period: 43 had iNTS infection and 1 had typhoid fever. The average annual iNTS incidence was 32.4 per 100,000 children aged < 5 years. None of the children had malaria or HIV infection, and only 7% were severely malnourished. Salmonella Enteritidis and Salmonella Java were the commonest NTS serovars identified. Pneumonia was the most common manifestation of iNTS disease, present in 20 (47%) children. Other manifestations included gastroenteritis, fever without a source, septic arthritis and meningitis. Salmonella Enteritidis was identified in 76% of those with pneumonia, significantly more frequently than in children with other manifestations. Over 25% of children with iNTS developed severe disease and nearly 10% suffered long term morbidity or mortality. While 78% of Salmonella Java isolates were multi-drug resistant, nearly all other isolates were susceptible to most antimicrobials, including ampicillin.

Conclusions

Bintulu Division in Sarawak observed a very high incidence of childhood iNTS infections. Enteric fever was uncommon. The epidemiology of invasive Salmonella infections in Malaysian Borneo differs considerably from that of neighbouring countries in Asia.

Epidemiology of common resistant bacterial pathogens in the countries of the Arab League

No uniformly organised collection of data regarding antimicrobial resistance has occurred in the countries of the Arab League. 19 countries of the Arab League have published data for antimicrobial susceptibility for the WHO priority organisms, and seven of 14 of these organisms are included in this Review (Escherichia coli, Klebsiella spp, Pseudomonas aeruginosa, Acinetobacter baumannii, Salmonella spp, Staphylococcus aureus, and Streptococcus pneumoniae). Although E coli and Klebsiella spp resistance to third-generation cephalosporins is common in all countries, with prevalence reaching more than 50% in Egypt and Syria, carbapenem resistance is emerging, albeit with a prevalence of less than 10%. Conversely, a large amount of carbapenem resistance has been reported for P aeruginosa and A baumannii across the Arab League, reaching 50% and 88% of isolates in some countries. As for Salmonella spp, the prevalence of fluoroquinolone resistance has exceeded 30% in several areas. With regards to the Gram-positive pathogens, the prevalence of meticillin resistance in S aureus is reported to be between 20% and 30% in most countries, but exceeds 60% in Egypt and Iraq. The prevalence of penicillin non-susceptibility among pneumococci has reached more than 20% in Algeria, Egypt, Morocco, Saudi Arabia, and Tunisia. These findings highlight the need for structured national plans in the region to target infection prevention and antimicrobial stewardship.

Campylobacteriosis, Salmonellosis, Yersiniosis, and Listeriosis as Zoonotic Foodborne Diseases: A Review

Zoonoses are diseases transmitted from animals to humans, posing a great threat to the health and life of people all over the world. According to WHO estimations, 600 million cases of diseases caused by contaminated food were noted in 2010, including almost 350 million caused by pathogenic bacteria. Campylobacter, Salmonella, as well as Yersinia enterocolitica and Listeria monocytogenes may dwell in livestock (poultry, cattle, and swine) but are also found in wild animals, pets, fish, and rodents. Animals, often being asymptomatic carriers of pathogens, excrete them with faeces, thus delivering them to the environment. Therefore, pathogens may invade new individuals, as well as reside on vegetables and fruits. Pathogenic bacteria also penetrate food production areas and may remain there in the form of a biofilm covering the surfaces of machines and equipment. A common occurrence of microbes in food products, as well as their improper or careless processing, leads to common poisonings. Symptoms of foodborne infections may be mild, sometimes flu-like, but they also may be accompanied by severe complications, some even fatal. The aim of the paper is to summarize and provide information on campylobacteriosis, salmonellosis, yersiniosis, and listeriosis and the aetiological factors of those diseases, along with the general characteristics of pathogens, virulence factors, and reservoirs.