Emergence of multidrug-resistant Salmonella spp. and isolates with reduced susceptibility to ciprofloxacin in Kuwait and the United Arab Emirates

Salmonella enterica serotypes causing infection in Kuwait during 2018-2021, determined by multi-locus sequence typing or whole genome sequencing

Salmonellosis due to non-typhoidal Salmonellae (NTS) is a zoonotic infection that has epidemiological uniqueness in different settings. The current study aimed to determine the serotypes and the genetic diversity of human Salmonella enterica isolates causing infection in Kuwait. Isolates were obtained from feces of healthy adults and diarrheal patients between 2018 and 2021. Multi-locus sequence typing (MLST) was used to study sequence types (STs) and infer serotypes. Whole genome sequencing (WGS) was used to investigate six selected isolates, which included two isolates from a foodborne outbreak and two isolates whose serotypes could not be determined. Antibiotic susceptibility was studied by E-test and interpreted according to the Clinical and Laboratory Standards Institute guidelines. During the study period, 112/8,019 stool samples, 39/129,130 blood samples, 4/1,835 tissue samples, 3/1,209 pleural fluids, 3/9,388 pus samples, 4/80,799 urine samples, 1/7,053 endotracheal secretions, and 1/18 liver abscess samples were culture positive for Salmonella, yielding a total of 167 isolates with 30 different serotypes. S. Enteritidis (36.5%, n = 61), S. Typhimurium (14.97%, n = 25), S. Kentucky (5.9%, n = 10), and S. Newport (5.9%, n = 10) were the predominant serotypes. A new sequence type, ST 10217 corresponding to S. Schwarzengrund, was found by WGS. Two S. Enteritidis isolates from the foodborne outbreak showed a unique phylogenetic profile. In the phylogenetic analysis of serotypes, the number of clades was equal to the number of STs. No resistance to carbapenems was found among the isolates. This study provided data on the epidemiology of Salmonella serotypes causing infection in Kuwait.IMPORTANCEHuman salmonellosis due to nontyphoid Salmonellae is a major foodborne disease throughout the world. We determined the serotypes of isolates causing salmonellosis in Kuwait during the study period. We inferred the serotypes of isolates based on their sequence types as determined by multi-locus sequence typing, which is more amenable to laboratories than the traditional serotyping. By whole genome sequencing, we determined that the strain causing a foodborne outbreak was unique, and a new sequence type not in the serotyping scheme represented a rare serotype. We learnt the resistance pattern of isolates and lack of resistance to carbapenems that will be useful for treating multi-drug-resistant infection. Our data will contribute to planning strategies for treatment and control of salmonellosis and the epidemiology of salmonellosis in the Middle East.

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.

Whole genome sequencing of Salmonella enterica serovars isolated from humans, animals, and the environment in Lagos, Nigeria

BACKGROUND

Salmonella infections remain an important public health issue worldwide. Some serovars of non-typhoidal Salmonella (NTS) have been associated with bloodstream infections and gastroenteritis, especially in children in Sub-Saharan Africa with circulating S. enterica serovars with drug resistance and virulence genes. This study identified and verified the clonal relationship of Nigerian NTS strains isolated from humans, animals, and the environment.

METHODS

In total, 2,522 samples were collected from patients, animals (cattle and poultry), and environmental sources between December 2017 and May 2019. The samples were subjected to a standard microbiological investigation. All the isolates were identified using Microbact 24E, and MALDI-TOF MS. The isolates were serotyped using the Kauffmann-White scheme. Antibiotic susceptibility testing was conducted using the disc diffusion method and the Vitek 2 compact system. Virulence and antimicrobial resistance genes, sequence type, and cluster analysis were investigated using WGS data.

RESULTS

Forty-eight (48) NTS isolates (1.9%) were obtained. The prevalence of NTS from clinical sources was 0.9%, while 4% was recorded for animal sources. The serovars identified were S. Cotham (n = 17), S. Give (n = 16), S. Mokola (n = 6), S. Abony (n = 4), S. Typhimurium (n = 4), and S. Senftenberg (n = 1). All 48 Salmonella isolates carried intrinsic and acquired resistant genes such as aac.6…Iaa, mdf(A), qnrB, qnrB19 genes and golT, golS, pcoA, and silP, mediated by plasmid Col440I_1, incFIB.B and incFII. Between 100 and 118 virulence gene markers distributed across several Salmonella pathogenicity islands (SPIs), clusters, prophages, and plasmid operons were found in each isolate. WGS revealed that strains of each Salmonella serovar could be assigned to a single 7-gene MLST cluster, and strains within the clusters were identical strains and closely related as defined by the 0 and 10 cgSNPs and likely shared a common ancestor. The dominant sequence types were S. Give ST516 and S. Cotham ST617.

CONCLUSION

We found identical Salmonella sequence types in human, animal, and environmental samples in the same locality, which demonstrates the great potential of the applied tools to trace back outbreak strains. Strategies to control and prevent the spread of NTS in the context of one's health are essential to prevent possible outbreaks.

Typhoid Fever in the Eastern Mediterranean Region: A Systematic Review, 1990-2021

The occurrence and antimicrobial resistance (AMR) of typhoid fever in the WHO Eastern Mediterranean Region (EMR) are poorly characterized. Robust surveillance data are needed to inform strategies for typhoid control and prevention in the region. We conducted a systematic review of typhoid fever occurrence, complications, and AMR patterns in EMR countries. We identified 70 studies published from 1990 to 2021, including a total of 44,541 cases with blood culture confirmed typhoid fever in 12 EMR countries, with 48 (69%) studies and 42,008 cases from Pakistan. Among 56 studies with AMR data, fluroquinolone (68% of 13,013 tested isolates), and multidrug resistance (40% of 15,765 tested isolates) were common. Forty (57%) of the 56 studies were from Pakistan, and all reports of extensively drug resistant Salmonella Typhi (48% of 9,578 tested isolates) were from studies in Pakistan. Our findings support the need for continued efforts to strengthen surveillance and laboratory capacity for blood-culture detection of typhoid fever in the region, including data from an ongoing collaboration among CDC, the American University of Beirut, and the WHO EMR office.

Prevalence and Antimicrobial Resistance of Salmonella in Poultry Products in Central Ethiopia

Salmonellosis is a bacterial infection caused by salmonella, a member of the Enterobacteriaceae family. From December 2021 to May 2021, a cross-sectional study was carried out to isolate Salmonella from poultry farms in the towns of Bishoftu and Adama and to determine the antimicrobial susceptibility frequency of the isolates. A total of 384 samples were tested for the presence of Salmonella, including 259 feces, 56 eggs, and 69 types of meat, using the ISO, 2002 standard procedures. The raw data were organized, coded, and entered into an Excel spreadsheet before being analyzed with STATA via descriptive analysis with chi-square. From 384 collected samples, 62 (16.15%) isolates were obtained, with 9.9%, 3.65, and 2.6% found in feces, eggs, and meat, respectively. Statistically, there was a significant difference between breeds (p value = 0.036). Bovines had the highest prevalence (32.83%), while Saso had the lowest (30.81%). The variation within each sample type, housing condition, and age group was not statistically significant (p value >0.05). Antimicrobial resistance was found in 29 (96.77%) of the isolates. Ampicillin and sulphamethoxazole-trimethoprim were effective against all isolates. Salmonella was isolated from various locations, sample types, ages, and breeds, indicating a wider distribution. Salmonellosis detection isolates suggested that it could be an emerging poultry and public health issue. As a result, future research should concentrate on isolating and identifying salmonella from poultry in backyard systems and comparing it to that of an intensive farm, as well as molecular characterization for serotyping and genetic studies, as well as genes responsible for salmonella pathogenicity and drug resistance.

Occurrence and antimicrobial susceptibility patterns of Salmonella species from poultry farms in Ibadan, Nigeria

Background: Salmonella species are among the major foodborne pathogens causing diseases of economic and public health implications in poultry and humans globally.Objective: This study aimed to determine the occurrence and antimicrobial susceptibility patterns of Salmonella isolates from chickens in poultry farms in Ibadan, Southwest Nigeria.Methods: Cloacal swab samples (n = 360) were obtained from chickens randomly selected from 10 poultry farms in five local government areas of Ibadan, Oyo State, from 04 April 2018 to 20 November 2018. Bacterial identification and antimicrobial susceptibility testing were performed using established protocols. Data were analysed using descriptive statistics and Pearson’s chi-squared test at P ≤ 0.05 significance level.Results: The overall prevalence of Salmonella was 21.4%. There were statistically significant associations between Salmonella prevalence and the farm location (p = 0.003), age of chickens (p  0.001), and health status of chickens (p  0.001). All Salmonella isolates (n = 77; 100.0%) were resistant to cefuroxime. The isolates were also highly resistant to cotrimoxazole (n = 74; 96.1%), chloramphenicol (n = 73; 94.8%), meropenem (n = 72; 93.5%), gentamicin (n = 69; 89.6%), and tetracycline (n = 64; 83.1%).Conclusion: The presence of drug-resistant Salmonella in commercial layer chickens in Ibadan is a potential threat to consumer health as it increases the risk of carcass contamination and pathogen propagation, and limits the options to control and treat infections in humans and animals. Well-integrated national surveillance systems for monitoring Salmonella and antimicrobial resistance in poultry are critical. 

Anti-Salmonella and Antibiofilm Potency of Salvia officinalis L. Essential Oil against Antibiotic-Resistant Salmonella enterica

Raw milk is a significant vehicle for the transmission of different infections. In the present study, we focused on Salmonella enterica from raw milk and its resistance to various antibacterial drugs. Furthermore, we have investigated the antimicrobial and antibiofilm effects of essential oil (EO) obtained from Salvia officinalis L. leaves that were collected from the Aljouf region, Saudi Arabia, against S. enterica. One-dozen strains of S. enterica were found in a batch of a hundred milk samples, and those S. enterica strains were shown to be resistant to several antibiotics, particularly the β-lactam group of antimicrobial drugs. Against multidrug-resistant S. enterica, the inhibitory zones for EO from S. officinalis leaves were found to be 21 mm in diameter. S. officinalis EO at 5% concentration showed a remarkable in vitro inhibitory activity toward the biofilm growth of different S. enterica isolates. Analysis of EO by GC-MS identified 21 distinct components, accounting for 89.94% of the total oil component. The most prominent compounds were 1,8-cineole (39.18%), β-caryophyllene (12.8%), and α--terpineol (10.3%). Taken together, our results unequivocally confirm that the S. officinalis EOs exert numerous bioactivities. Thus, the well-deserved attention on S. officinalis EO usage as a food preservative and adjunctive remedy for bacterial food-borne diseases is justified.

Epidemiology, Serogroups and Resistance of Salmonella During a 15-Year Period (2006-2020) in Kuwait

Purpose

The aim of the study was to investigate the changing pattern in serogroup distribution and antimicrobial resistance of all Salmonella spp. isolated from patients attending the Mubarak Al Kabeer Hospital (MAK), Kuwait from 2006 to 2020.

Patients and Methods

A retrospective study of all enrolled patients attending the MAK with culture-positive Salmonella spp. was undertaken. Data on age, gender, culture sample and serogroup were obtained from the laboratory information system. A prospective antimicrobial susceptibility of all stock isolates was carried out using E test. The trend rates of Salmonella serogroups and antimicrobial resistance were compared among 5 periods: 2006–2008, 2009–2011, 2012–2014, 2015–2017, and 2018–2020.

Results

A total of 700 isolates were identified. The majority of the isolates were from the stool (77.6%), followed by the blood (16.4%). The most common serogroups were serogroup D (37.6%) and B (23.4%). There was a significant rise in ciprofloxacin resistance from 32.2% during 2006–2008 to 54.3% during 2018–2020 and from 32.5% during 2009–2011 to 54.3% during 2018–2020 (P=0.0001, respectively). The resistance trend to cefotaxime was at relatively low levels ranging from 0% to 3.4% through 2006–2008 to 2018–2020. There was a significant drop of the resistance to ampicillin from 23.6% in 2015–2017 to 12.3% in 2006–2008 to 2018–2020 (P=0.03). Trimethoprim/sulfamethoxazole resistance dropped significantly from 14.5 to 3.6% (P=0.002) during 2006–2008 to 2018–2020 and then from 13.5 to 3.6% (P=0.02) during 2015–2017 to 2018–2020. One hundred and seventeen (16.7%) isolates were multidrug-resistant.

Conclusion

Continuous surveillance of Salmonella and its antimicrobial resistance is important for antibiotic policy formulation for invasive Salmonella infections.

Genomic analysis of the first cases of extensively drug-resistant, travel-related Salmonella enterica serovar Typhi in Oman

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XDR S. Typhi is spreading widely to different countries, and has emerged in Oman

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Surveillance programs in Oman have detected these cases, allowing prompt treatment

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The WGS method has played a major role in characterizing XDR S. Typhi

Objectives

To highlight the importance of molecular testing in characterizing extensively drug-resistant (XDR) Salmonella Typhi (S. Typhi), and linking it to the current outbreak in Sindh, Pakistan.

Methods

Our study reports three travel-related typhoid fever cases caused by XDR S. Typhi that presented between January 2019 and August 2019. Antimicrobial susceptibility and genotyping with pulse-field gel electrophoresis (PFGE) were carried out. Whole-genome sequencing (WGS) was performed to characterize the genomic clonality in relation to the emerging outbreak of S. Typhi in Sindh, Pakistan, and to study the molecular resistance profiles.

Results

Laboratory testing revealed resistance to all first-line antibiotics (i.e ampicillin, chloramphenicol, and trimethoprim-sulfamethoxazole), as well as to quinolones and third-generation cephalosporins, leading to a change in the patients’ therapy to the use of carbapenems. Classical MLST (cMLST) revealed that the strains were of sequence type 1 (ST1) and the core genome sequence (cgWGS) analysis closely clustered our strains with internationally reported strains from Pakistan, India, and the UK. The strains were found to carry a bla_CTX-15 gene-harbouring IncY plasmid, which encodes resistance to ceftriaxone.

Conclusions

Our report alerts clinicians to the use of appropriate empirical treatments in such scenarios, and highlights the significance of the global spread of XDR S. Typhi.

Assessment of implementation of antibiotic stewardship program in surgical prophylaxis at a secondary care hospital in Ras Al Khaimah, United Arab Emirates

Antibiotic overuse is a major factor for causing antibiotic resistance globally. However, only few studies reported the implementation and evaluation of antimicrobial stewardship programs in Gulf Cooperation Council. This study was conducted within 8-months periods to evaluate the effect of the newly implemented antibiotic stewardship program on improving the prescribing practice of surgical antibiotic prophylaxis in a secondary care hospital in the United Arab Emirates by releasing local hospital guidelines. The data of 493 in patients were documented in the predesigned patient profile form and the prescribing practice of surgical antibiotic prophylaxis for clean and clean-contaminant surgical procedures was compared and analyzed two months’ prior (period A) and post (period B) the implementation of antibiotic stewardship program. The 347 patient’s data (PD) were analyzed during period A and 146 PD during period B. The prescription of piperacillin/tazobactam was decreased from 2.4% from all surgical prophylaxis antibiotic orders in period A to 0% in period B. The appropriateness of the antibiotic therapy was found to differ non significantly for the selection of prophylactic antibiotic (p = 0.552) and for the timing of first dose administration (p = 0.061) between A and B periods. The total compliance was decreased non significantly (P = 0.08) from 45.3 to 40.2%. Overall, the guidelines have improved the prescribing practice of antibiotics prior to surgery. However, further improvement can be achieved by initiating educational intervention via cyclic auditing strategy.

The phenotypic and molecular characteristics of antimicrobial resistance of Salmonella enterica subsp. enterica serovar Typhimurium in Henan Province, China

Background

Salmonella enterica subsp. enterica serovar Typhimurium infections continue to be a significant public health threat worldwide. The aim of this study was to investigate antibiotic resistance among 147 S. Typhimurium isolates collected from patients in Henan, China from 2006 to 2015.

Methods

147 S. Typhimurium isolates were collected from March 2006 to November 2015 in Henan Province, China. Antimicrobial susceptibility testing was performed, and the resistant genes of ciprofloxacin, cephalosporins (ceftriaxone and cefoxitin) and azithromycin were detected and sequenced. Clonal relationships were assessed by multilocus sequence typing (MLST) and pulsed-field gel electrophoresis (PFGE).

Results

Of the 147 isolates, 91.1% were multidrug resistant (MDR), with 4.1% being resistant to all antibiotic classes tested. Of concern, 13 MDR isolates were co-resistant to the first-line treatments cephalosporins and ciprofloxacin, while three were also resistant to azithromycin. Seven PFGE patterns were identified among the 13 isolates. All of the isolates could be assigned to one of four main groups, with a similarity value of 89%. MLST assigned the 147 isolates into five STs, including two dominant STs (ST19 and ST34). Of the 43 ciprofloxacin-resistant isolates, 39 carried double gyrA mutations (Ser83Phe, Asp87Asn/Tyr/Gly) and a single parC (Ser80Arg) mutation, including 1 isolate with four mutations (gyrA: Ser83Phe, Asp87Gly; parC: Ser80Arg; parE: Ser458Pro). In addition, 12 isolates not only carried mutations in gyrA and parC but also had at least one plasmid-mediated quinolone resistance (PMQR) gene. Among the 32 cephalosporin-resistant isolates, the most common extended-spectrum β-lactamase (ESBL) gene was bla_OXA-1, followed by bla_CTX-M, bla_TEM-1, and bla_CMY-2. Moreover, the mphA gene was identified in 5 of the 15 azithromycin-resistant isolates. Four MDR isolates contained ESBL and PMQR genes, and one of them also carried mphA in addition.

Conclusion

The high level of antibiotic resistance observed in S. Typhimurium poses a great danger to public health, so continuous surveillance of changes in antibiotic resistance is necessary.

Molecular Characterization Of Pathogenic Salmonella Spp From Raw Beef In Karachi, Pakistan

The aim of the present study was to estimate the prevalence of Salmonella and investigate the dominant serovars distribution in raw beef and to screen the isolated serovars for the prescense of beta-lactamases and virulence genes. A total of 150 samples of raw beef sold at butcher shops (n = 75) and supermarkets (n = 75) in Karachi city were collected (50 samples each from muscles, lymph nodes, and minced beef). The samples were cultured according to the ISO-6579-1guidlines. The overall prevalence of Salmonella strains was found to be 21.34%. A total of 56 isolates of Salmonella belonging to four serogroups (Salmonella Pullorum, Salmonella Enteritidis, Salmonella Typhimurium and Salmonella Choleraesuis) were isolated from beef muscles (12%), lymph nodes (24%) and minced beef (28%) samples collected from butcher shops (av. 21.34%). No Salmonella was detected in beef samples collected from supermarkets. S. Enteritidis contamination was highest (37.5 %), followed by S. Choleraesuis (30.4%), S. Pullorum (19.6%) and S. Typhimurium (12.5 %). Antibiotic susceptibility testing revealed that Salmonella isolates were highly resistant to Oxytetracycline (90%), Ampicillin (90.5%), Amoxicillin (81.1%), Tetracycline (76%), Neomycin, (79.8%) and Ciprofloxacin (61.4%). The Salmonella isolates examined were more susceptible to the Cephalosporin antibiotics such as Cefixime (43.2%), Cefepime (48.2) and Cefoxitin (49.8%). PCR based screening of blaTEM, blaCTX-M and blaSHV revealed that blaCTX-M and blaTEM were the dominant resistant genes in S. Enteritidis and S. Typhimurium followed by S. Pullorum and S. Choleraesuis whereas blaSHV was the least detected beta-lactamase in Salmonella isolates. Virulence genes screening revealed that at least five genes were present in all the serovars, highest being present in S. Enteritidis (12/17) and S. Typhimurium (12/17). S. Cholerasuis (5/17) carried the least number of virulence genes followed by S. Pullorum (6/17). The present data suggest that beef samples from butcher shops of Karachi city are heavily contaminated with MDR Salmonella. The presence of resistance and virulence genes in MDR strains of Salmonella may play a significant role in transmission and development of Salmonella infection in humans.

Prevalence of Multidrug Resistant Salmonellae with Increasing Frequency of Salmonella enterica Serovars Kentucky and Virchow among Hospitalized Diarrheal Cases in and around Delhi, India

Non-typhoidal salmonellae (NTS) are a major cause of acute diarrhea with characteristic multidrug resistance (MDR). In a hospital-based study, 81 NTS were isolated and tested for serotypes and antimicrobial resistance (AMR). Salmonella enterica isolates were classified into 7 different typable serovars, however, 19 (23%) isolates remained untypable. The most common serovars were S. Kentucky (48%), and S. Virchow (22%). Most of the NTS isolates displayed resistance to nalidixic acid (NA) (73%), ciprofloxacin (CIP) (48%), ampicillin (AM) and norfloxacin (NOR) (36% each), and gentamicin (CN) (31%). The AMR profiles for CN and NA; and AM, CIP, NA and NOR, were found to be high in S. Virchow (83%) and S. Kentucky (43%), respectively. Analysis of the pulsed-field gel electrophoresis patterns of S. Kentucky revealed 3 clusters. S. Kentucky has clones closely related to become prominent in recent years in Delhi. The AMR appears to be consistent with the change in MDR patterns during 2014-2017. The observed prevalence of S. Kentucky and S. Virchow in large numbers of diarrheal cases is novel. The NTS are mostly resistant to fluoroquinolones, which is the current drug of choice for treating diarrheal cases. MDR is very common among clonally related S. Kentucky.

Childhood Diarrhoea in the Eastern Mediterranean Region with Special Emphasis on Non-Typhoidal Salmonella at the Human⁻Food Interface

Diarrhoeal disease is still one of the most challenging issues for health in many countries across the Eastern Mediterranean region (EMR), with infectious diarrhoea being an important cause of morbidity and mortality, especially in children under five years of age. However, the understanding of the aetiological spectrum and the burden of enteric pathogens involved in diarrhoeal disease in the EMR is incomplete. Non-typhoidal Salmonella (NTS), the focus of this review, is one of the most frequently reported bacterial aetiologies in diarrhoeal disease in the EMR. Strains of NTS with resistance to antimicrobial drugs are increasingly reported in both developed and developing countries. In the EMR, it is now widely accepted that many such resistant strains are zoonotic in origin and acquire their resistance in the food-animal host before onward transmission to humans through the food chain. Here, we review epidemiological and microbiological aspects of diarrhoeal diseases among children in the EMR, with emphasis on the implication and burden of NTS. We collate evidence from studies across the EMR on the zoonotic exposure and antimicrobial resistance in NTS at the interface between human and foods of animal origin. This review adds to our understanding of the global epidemiology of Salmonella with emphasis on the current situation in the EMR.

Prevalence, risk factors and antimicrobial resistance of Salmonella diarrhoeal infection among children in Thi-Qar Governorate, Iraq

We conducted a hospital-based cross-sectional study among children aged <5 years in Thi-Qar Governorate, south-eastern Iraq, in order to examine the prevalence, risk factors and antimicrobial resistance associated with gastroenteritis caused by Salmonella infection. From 320 diarrhoea cases enrolled between March and August 2016, 33 (10·3%, 95% confidence interval (CI) 8·4-12·4) cases were stool culture-positive for non-typhoidal Salmonella enterica. The most commonly identified serovar was Typhimurium (54%). Multivariable logistic regression analysis indicated that the odds of Salmonella infection in children from households supplied by pipe water was 4·7 (95% CI 1·6-13·9) times higher compared with those supplied with reverse osmosis treated water. Similarly, children from households with domestic animals were found to have a higher odds (OR 10·5; 95% CI 3·8-28·4) of being Salmonella stool culture-positive. The likelihood of Salmonella infection was higher (OR 3·9; 95% CI 1·0-6·4) among children belonging to caregiver with primary vs. tertiary education levels. Lower odds (OR 0·4; 95% CI 0·1-0·9) of Salmonella infection were associated with children exclusively breast fed as compared with those exclusively bottle fed. Salmonella infection was three times lower (95% CI 0·1-0·7) in children belonging to caregiver who reported always washing hands after cleaning children following defecation, vs. those belonging to caregivers who did not wash hands. The antimicrobial resistance profile by disc diffusion revealed that non-susceptibility to tetracycline (78·8%), azithromycin (66·7%) and ciprofloxacin (57·6%) were the most commonly seen, and 84·9% of Salmonella isolates were classified as multi-drug resistant. This is the first study on prevalence and antimicrobial resistance of Salmonella infection among children in this setting. This work provides specific epidemiological data which are crucial to understand and combat paediatric diarrhoea in Iraq.

The Role of AcrAB-TolC Efflux Pump in Mediating Fluoroquinolone Resistance in Naturally Occurring Salmonella Isolates from China

The involvement of AcrAB-TolC efflux pump in regulating fluoroquinolone resistance of naturally occurring Salmonella isolates is insufficiently investigated. In this study, the regulatory genes, acrR, ramR, marRAB, and soxRS of AcrAB-TolC efflux pump, of 27 naturally occurring fluoroquinolone-resistant Salmonella isolates collected in China were sequenced. The expression levels of acrB, ramA, marA, and soxS were also examined using quantitative real-time polymerase chain reaction. Gene alterations were mainly observed for acrR (three mutation types) and ramR (four mutation types), not for marRAB (no mutation) or soxRS (one mutaton type). Overexpressions were also mainly observed for acrB and ramA, not for marA or soxS. Some mutations/deletions in ramR caused highly elevated expression of ramA. Complementation with wild-type ramR gene reduced mRNA levels of acrB and ramA by 1.7- to 2.2-fold and 10.5- to 30.1-fold, respectively, and lowered fluoroquinolones (FQ) minimum inhibitory concentrations by 2- to 8-fold. Neither MarA nor SoxS was found to be associated with increased FQ resistance. This study shows that the AcrAB efflux pump is playing a role in mediating fluoroquinolone resistance, and RamA may be the major global regulator of AcrAB-TolC-mediated fluoroquinolone resistance in Salmonella.

SEROTYPING AND ANTIMICROBIAL DRUG RESISTANCE OF SALMONELLA ISOLATED FROM LETTUCE AND HUMAN DIARRHEA SAMPLES IN BURKINA FASO

BACKGROUND

In Burkina Faso dirty water in particular those of the stoppings and the gutter ones are used for vegetables irrigation in the gardens. The aim of this study was to determine the prevalence and antibiotic susceptibility of Salmonella serotypes from humans and lettuce samples inBurkina Faso. Materials and Methods:Salmonella strains isolated from patients in 2009 to 2015 and lettuce samples in 2014 in Burkina Faso were serotyped using specific antisera. All strains were subjected to a set of 14 antibiotics to study their antibiogram by using Baeur-Kirby disk diffusion method.

RESULTS

Out of 154 Salmonella isolated, 60 were from human and 94 from lettuce samples. Serotyping revealed four different serotypes and 39% (60) untypeable strains from human and lettuce (14 and 46 strains). Salmonella serotypes from human and lettuce samples were: Paratyphi A (10% and 22%), Paratyphi B (34% and 8%), Paratyphi C (14% and 18%) and Typhi (21% and 1%). A high resistance of Salmonella Paratyphi B and Salmonella spp to tetracycline were 70% from human and 35 % from lettuce samples. Multiresistance was observed to tetracycline, chloramphenicol and amoxicillin/clavulanic-acid or ampicillin with Salmonella ParatyphiB 35% and Salmonella Typhi 33% from human samples and Salmonella spp 4% from lettuce samples.

CONCLUSION

This study showed the diversity of Salmonella serotypes from both clinical and environmental samples and emergence of multiresistant Salmonella to antibiotics in Burkina Faso. A lettuce is a potential source of transmission of Salmonella causing diarrhea among human in Burkina Faso. List of non-standard Abbreviations : HDB: Hôpital du District de Bogodogo, LNSP: Laboratoire National de Santé Publique, DSG : District Sanitaire de Gourcy, DSB : District Sanitaire de Boromo.

Drug utilization review of cephalosporins in a secondary care hospital in United Arab Emirates

Background Cephalosporins are one of the most commonly used antibiotics in United Arab Emirates (UAE). Few studies have been carried out to evaluate the antibiotic utilization pattern in UAE in spite of the obvious increase in cephalosporins resistance during the past decade. Objective To assess the prescriptions pattern of cephalosporins among physicians at a secondary care hospital in Ras Al Khaimah, UAE. Method This observational prospective study was carried out during October 2013 to April 2014. The data of in patients were documented in the predesigned patient profile form and was analyzed for patient's, drug's and drug's therapy related parameters. Results The 3rd generation cephalosporins constituted 83.6 % of the prescriptions, with ceftriaxone being the most commonly used one (81.1 %). They were mainly prescribed for the treatment of the lower respiratory tract infections (60.2 %). Seven (3.5 %) different ADRs linked to cephalosporin use were observed ranging from oral thrush to clostridium difficile infection. A total of 1039 antimicrobial and nonantimicrobial medications were prescribed concomitantly with cephalosporins. Conclusion The 3rd generation cephalosporins were commonly prescribed by parenteral route. Thus, there is a strong need for rationalizing their use to preserve their efficacy and prevent the development of resistance in the region.

Antibacterial Potentials of Ve<i>rnonia amygdalina</i> against Antibiotic-Resistant <i>Salmonella</i> Specie Isolated from Nworie River, Imo State, Nigeria

Salmonella specie were isolated from Nworie River and then tested against several antibiotics to include; Gentamycin, Streptomycin, Amoxycillin, Kanamycin, Oxacillin, Ofloxacin, Imipenem, Ciprofloxacin, Aztreonam and Ceftazidime. Salmonella isolates obtained from the river were resistant to at least three different antibiotics. All isolates were resistant to Amoxycillin, Oxacillin and Iminipem showing a 100% resistant rate, while showing sensitivity to Ciprofloxacin, Aztreonam, Gentamycin, Ceftazidime, Kanamycin, Streptomycin, and Ofloxacin at sensitivity rates of 71.4%, 7.1%, 77.1%, 11.4%, 44.3%, 48.6% and 78.6% respectively. The antibiotic-resistant Salmonella species were further tested against the aqueous, ethanol and acetone extracts of Vernonia amygdalina leaf, stem and roots to assess their antibacterial potential at a concentration of 100mg/ml. Aqueous extracts of the leaf, stem and roots showed no activity against antibiotic resistant Salmonella isolate, while the ethanol and acetone extracts showed activity rates of 20% and 17% for roots, 14.3% and 12.9% for stem, and, 15.7% and 11.4% for leaf. The results from this study further confirms the antibacterial potentials of Vernonia amygdalina against antibiotic-resistant bacterial isolates.

Antibacterial Potentials of Ve<i>rnonia amygdalina</i> against Antibiotic-Resistant <i>Salmonella</i> Specie Isolated from Nworie River, Imo State, Nigeria

Salmonella specie were isolated from Nworie River and then tested against several antibiotics to include; Gentamycin, Streptomycin, Amoxycillin, Kanamycin, Oxacillin, Ofloxacin, Imipenem, Ciprofloxacin, Aztreonam and Ceftazidime. Salmonella isolates obtained from the river were resistant to at least three different antibiotics. All isolates were resistant to Amoxycillin, Oxacillin and Iminipem showing a 100% resistant rate, while showing sensitivity to Ciprofloxacin, Aztreonam, Gentamycin, Ceftazidime, Kanamycin, Streptomycin, and Ofloxacin at sensitivity rates of 71.4%, 7.1%, 77.1%, 11.4%, 44.3%, 48.6% and 78.6% respectively. The antibiotic-resistant Salmonella species were further tested against the aqueous, ethanol and acetone extracts of Vernonia amygdalina leaf, stem and roots to assess their antibacterial potential at a concentration of 100mg/ml. Aqueous extracts of the leaf, stem and roots showed no activity against antibiotic resistant Salmonella isolate, while the ethanol and acetone extracts showed activity rates of 20% and 17% for roots, 14.3% and 12.9% for stem, and, 15.7% and 11.4% for leaf. The results from this study further confirms the antibacterial potentials of Vernonia amygdalina against antibiotic-resistant bacterial isolates.

Salmonella burden in Lebanon

Salmonellosis is a disease that represents a major public health concern in both developing and developed countries. The aim of this article is to evaluate the public health burden of Salmonella illness in Lebanon. The current scope of the Salmonella infection problem was assessed in relation to disease incidence and distribution with respect to age, gender and district. Factors that provide a better understanding of the magnitude of the problem were explored and highlighted. Data reported to the Epidemiologic Surveillance Department at the Lebanese Ministry of Public Health between 2001 and 2013 was reviewed. Information obtained was compared to information reported regionally and globally. The estimated true incidence was derived using multipliers from the CDC and Jordan. A literature review of all published data from Lebanon about Salmonella susceptibility/resistance patterns and its serious clinical complications was conducted. The estimated incidence was 13·34 cases/100 000 individuals, most cases occurred in the 20-39 years age group with no significant gender variation. Poor and less developed districts of Lebanon had the highest number of cases and the peak incidence was in summer. Reflecting on the projected incidence derived from the use of multipliers indicates a major discrepancy between what is reported and what is estimated. We conclude that data about Salmonella infection in Lebanon and many Middle Eastern and developing countries lack crucial information and are not necessarily representative of the true incidence, prevalence and burden of illness.

Real time PCR gene profiling and detection of Salmonella using a novel target: The siiA gene

The objective of this study was to develop and evaluate a SYBR Green real time PCR method for the specific detection of Salmonella spp using a novel target, the siiA gene. Primer specificity testing was done on a panel of 76 Salmonella strains and 32 non-Salmonella strains. The primers directed against the siiA gene amplified all Salmonella strains tested, while non-Salmonella strains were not amplified. The melting temperatures of the 107 bp amplicons were consistently specific as they gave melting peaks around 75.5°C. The precision of the assay, based on intra and inter-run variations, was shown to be widely acceptable. In the second part of this study, 45 Salmonella strains were screened for the presence of 6 virulence-associated genes (sopB, cat2, safC, sefB and SC1248) located in several Salmonella Pathogenicity Islands (SPIs) and the spvC gene from the Salmonella virulence plasmid. The prevalence of these genes ranged from 51% to 100%. Variable virulence gene profiles were obtained even within the same serotype.

Sensitization of intracellular Salmonella enterica serovar Typhimurium to aminoglycosides in vitro and in vivo by a host-targeted antimicrobial agent

Aminoglycosides exhibit relatively poor activity against intracellular Salmonella enterica serovar Typhimurium due to their low permeativity across eukaryotic cell membranes. Previously, we identified the unique ability of AR-12, a celecoxib-derived small-molecule agent, to eradicate intracellular Salmonella Typhimurium in macrophages by facilitating autophagosome formation and suppressing Akt kinase signaling. In light of this unique mode of antibacterial action, we investigated the ability of AR-12 to sensitize intracellular Salmonella to aminoglycosides in macrophages and in an animal model. The antibacterial activities of AR-12 combined with various aminoglycosides, including streptomycin, kanamycin, gentamicin, and amikacin, against intracellular S. Typhimurium in murine RAW264.7 macrophages were assessed. Cells were infected with S. Typhimurium followed by treatment with AR-12 or individual aminoglycosides or with combinations for 24 h. The in vivo efficacies of AR-12, alone or in combination with gentamicin or amikacin, were also assessed by treating S. Typhimurium-infected BALB/c mice daily for 14 consecutive days. Exposure of S. Typhimurium-infected RAW264.7 cells to a combination of AR-12 with individual aminoglycosides led to a reduction in bacterial survival (P < 0.05), both intracellular and extracellular, that was greater than that seen with the aminoglycosides alone. This sensitizing effect, however, was not associated with increased aminoglycoside penetration into bacteria or macrophages. Moreover, daily intraperitoneal injection of AR-12 at 0.1 mg/kg of body weight significantly increased the in vivo efficacy of gentamicin and amikacin in prolonging the survival of S. Typhimurium-infected mice. These findings indicate that the unique ability of AR-12 to enhance the in vivo efficacy of aminoglycosides might have translational potential for efforts to develop novel strategies for the treatment of salmonellosis.

Multi-drug resistance and reduced susceptibility to ciprofloxacin among Salmonella enterica serovar Typhi isolates from the Middle East and Central Asia

Typhoid fever is common in developing countries, with an estimated 120 million infections and 700 000 annual deaths, worldwide. Fluoroquinolones have been the treatment of choice for infection with multidrug-resistant (MDR) Salmonella enterica serovar Typhi (S. Typhi). However, alarming reports of fluoroquinolone-resistance and failure of typhoid fever treatment have recently been published. To determine the proportion of S. Typhi isolates with reduced susceptibility to ciprofloxacin (RSC) from six countries in the Middle East and Central Asia, 968 S. Typhi isolates collected between 2002 and 2007 from Egypt, Uzbekistan, Pakistan, Qatar, Jordan and Iraq were tested for antibiotic susceptibility to five antibiotics using the disc-diffusion method. MDR was defined as resistance to amicillin, chloramphenicol and trimethoprim-sulfamethoxazole. The E-test was employed to determine the MIC of ciprofloxacin only. Nalidixic acid resistance was evaluated as a marker for RSC. Interpretations were made according to CLSI guidelines. MDR strains were considerably more prevalent in Iraq (83%) and Pakistan (52%) compared with the other countries studied (13–52%). Nearly all isolates were susceptible (99.7%) to ceftriaxone. RSC was detected in a total of 218 isolates (22%), mostly from Iraq (54/59, 92%), Uzbekistan (98/123, 80%), Qatar (23/43, 54%) and Pakistan (31/65, 47%). Many of these (21%) were also MDR. Use of nalidixic acid resistance as an indicator for RSC was 99% sensitive and 98% specific. This study reinforces the need for routine antimicrobial susceptibility surveillance of enteric fever isolates and close review of current therapeutic policies in the region.

β-Lactamase production in key gram-negative pathogen isolates from the Arabian Peninsula

SUMMARY Infections due to Gram-negative bacilli (GNB) are a leading cause of morbidity and mortality worldwide. The extent of antibiotic resistance in GNB in countries of the Gulf Cooperation Council (GCC), namely, Saudi Arabia, United Arab Emirates, Kuwait, Qatar, Oman, and Bahrain, has not been previously reviewed. These countries share a high prevalence of extended-spectrum-β-lactamase (ESBL)- and carbapenemase-producing GNB, most of which are associated with nosocomial infections. Well-known and widespread β-lactamases genes (such as those for CTX-M-15, OXA-48, and NDM-1) have found their way into isolates from the GCC states. However, less common and unique enzymes have also been identified. These include PER-7, GES-11, and PME-1. Several potential risk factors unique to the GCC states may have contributed to the emergence and spread of β-lactamases, including the unnecessary use of antibiotics and the large population of migrant workers, particularly from the Indian subcontinent. It is clear that active surveillance of antimicrobial resistance in the GCC states is urgently needed to address regional interventions that can contain the antimicrobial resistance issue.

Detection of quinolone-resistance mutations in salmonella spp. Strains of epidemic and poultry origin

Mutations into codons Aspartate-87 (62%) and Serine-83 (38%) in QRDR of gyrA were identified in 105 Salmonella strains resistant to nalidixic acid (94 epidemic and 11 of poultry origin). The results show a high incidence of mutations associated to quinolone resistance but suggest association with others mechanisms of resistance.

Prevalence, serovars, phage types, and antibiotic susceptibilities of Salmonella strains isolated from animals in the United Arab Emirates from 1996 to 2009

The aim of this study was to give some insights into the prevalence, serovars, phage types, and antibiotic resistances of Salmonella from animal origin in the United Arab Emirates. Data on diagnostic samples from animals (n = 20,871) examined for Salmonella between 1996 and 2009 were extracted from the databases of the Central Veterinary Research Laboratory in Dubai and from typed strains (n = 1052) from the Robert Koch Institute, Wernigerode Branch in Germany and analyzed for general and animal-specific trends. Salmonella was isolated from 1,928 (9 %) of the 20,871 samples examined. Among the 1,052 typed strains, most were from camels (n = 232), falcons (n = 166), bustards (n = 101), antelopes (n = 66), and horses (n = 63). The predominant serovars were Salmonella Typhimurium (25 %), Salmonella Kentucky (8 %), followed by Salmonella Frintrop (7 %), and Salmonella Hindmarsh (5 %). When analyzed by animal species, the most frequent serovars in camels were Salmonella Frintrop (28 %) and Salmonella Hindmarsh (21 %), in falcons Salmonella Typhimurium (32 %), in bustards Salmonella Kentucky (19 %), in antelopes Salmonella Typhimurium (9 %), and in horses Salmonella Typhimurium (17 %) and S. Kentucky (16 %). Resistance of all typed Salmonella strains (n = 1052) was most often seen to tetracycline (23 %), streptomycin (22 %), nalidixic acid (18 %), and ampicillin (15 %). These data show trends in the epidemiology of Salmonella in different animal species which can be used as a base for future prevention, control, and therapy strategies.

Prevalence and antimicrobial resistance of Salmonella isolated from lactating cows and in contact humans in dairy farms of Addis Ababa: a cross sectional study

Background

Salmonella are the major pathogenic bacteria in humans as well as in animals. Salmonella species are leading causes of acute gastroenteritis in several countries and salmonellosis remains an important public health problem worldwide, particularly in the developing countries. The situation is more aggravated by the ever increasing rate of antimicrobial resistance strains. Cattle have been implicated as a source of human infection with antimicrobial resistant Salmonella through direct contact with livestock and through the isolation of antimicrobial resistant Salmonella from raw milk, cheddar cheese, and hamburger meat traced to dairy farms. Despiite the presence of many studies on the prevalence and antimicrobial susceptibility pattern of Salmonella in Ethiopia, nothing has been said on the degree of the situation among apparently healthy lactating cows and in contact humans. Hence this study was conducted to determine the prevalence and antimicrobial resistance pattern of Salmonella isolates from lactating cows and in contact humans in dairy farms of Addis Ababa.

Methods

a cross sectional study was conducted in Addis Ababa by collecting milk and faecal samples from lactating cows and stool samples from humans working in dairy farms. Samples were pre-enriched in buffered peptone water followed by selective enrichment using selenite cysteine and Rapaport-Vassilidis broths. Isolation and identification was made by inoculating the selectively enriched sample on to Xylose Lysine Deoxycholate agar followed by confirmation of presumptive colonies using different biochemical tests. The Kibry Bauer disk diffusion method was used for antimicrobial sensitivity testing.

Results

10.7% (21/195) of cows and 13.6% (3/22) of the human subjects sheded Salmonella. 83% resistance to two or more antimicrobials and 100% resistance to ampicillin were observed. Most of the isolates were relatively sensitive to ciprofloxacin, cotrimoxazole, and chloramphenicol.

Conclusion

High proportion of Salmonella isolates developed resistance to the commonly prescribed antimicrobials and this may be a considerable risk in the treatment of clinical cases. So, wise use of antimicrobials must be practiced to combat the ever increasing situation of antimicrobial resistance.

Serotype, genotype, and antimicrobial susceptibility profiles of Salmonella from chicken farms in Shanghai

Five hundred fifty samples were collected from five chicken farms in Shanghai during March 2005 to October 2006. Twenty-five samples tested positive for Salmonella from a total of 550 samples, of which 500 were obtained from feces of healthy chickens and 50 were obtained from diseased chicks. The 25 presumptive Salmonella isolates were confirmed by the API 20E identification kit. Serotyping of these isolates by agglutination tests with antiserum displayed seven serovars; genotyping of these isolates with multilocus sequence typing demonstrated six sequence type (ST) patterns (i.e., ST-11, ST-19, ST-92, ST-96, ST-290, and ST-367). The multilocus sequence typing data revealed that some of these strains, isolated from different farms, might have the same ST and might come from the same source. The susceptibilities of these strains to 14 antimicrobials were determined; most of the isolates (13 of 25) were resistant to doxycycline and tetracycline, and two isolates were resistant to cefotaxime and ceftazidime, but none was resistant to gentamicin or kanamycin.

Assessment of antimicrobial resistance transfer between lactic acid bacteria and potential foodborne pathogens using in vitro methods and mating in a food matrix

The transferability of antimicrobial resistance from lactic acid bacteria (LAB) to potential pathogenic strains was studied using in vitro methods and mating in a food matrix. Five LAB donors containing either erythromycin or tetracycline resistance markers on transferable elements were conjugally mated with LAB (Enterococcus faecalis, Lactococcus lactis) and pathogenic strains (Listeria spp., Salmonella ssp., Staphylococcus aureus, and Escherichia coli). In vitro transfer experiments were carried out with the donors and recipients using both the filter and plate mating methods. The food matrix consisted of fermented whole milk (fermented with the LAB donors) with the pathogenic recipients added as contaminants during the production process. All transconjugants were confirmed by phenotypic and molecular methods. Erythromycin resistance transfer from LAB strains to Listeria spp. was observed using both in vitro mating methods at high transfer frequencies of up to 5.1 x 10(-4) transconjugants per recipient. Also, high frequency transfer (ranging from 2.7 x 10(-8) up to 1.1 x 10(-3) transconjugants per recipient) of both erythromycin and tetracycline-resistance was observed between LAB species using in vitro methods. No resistance transfer was observed to Salmonella spp., Staphylococcus aureus, and E. coli. The only conjugal transfer observed in the fermented milk matrix was for tetracycline resistance between two LAB strains (at a transfer frequency of 2.6 x 10(-7) transconjugants per recipients). This study demonstrates the transfer of antimicrobial resistance from LAB to Listeria spp. using in vitro methods and also the transfer of resistance between LAB species in a food matrix. It highlights the involvement of LAB as a potential source of resistance determinants that may be disseminated between LAB and pathogenic strains including Listeria spp. Furthermore, it indicates that food matrices such as fermented milks may provide a suitable environment to support gene exchange.

Characterization of extended-spectrum beta-lactamases in Salmonella spp. at a tertiary hospital in Durban, South Africa

Extended-spectrum beta-lactamases (ESBLs) were characterized in 41 Salmonella spp. isolates from patients admitted to a pediatric ward of a tertiary hospital in Durban, South Africa. The most common (17/ 41) serotype was Salmonella enterica serotype Typhimurium, followed by S. enterica serotype Isangi (16/41), S. enterica serotype Saint-paul (2/41), S. enterica serotype Kissi (2/41), S. enterica serotype Kivu (2/41), and S. enterica serotype Reading (1/41). All isolates were resistant to ampicillin, amoxicillin-clavulanate, piperacillin, ceftazidime, and aztreonam but susceptible to meropenem. SHV-12 found in 39% of the isolates was the most common ESBL. TEM-63 was produced in 29% and TEM-116 in 10% of the isolates, and TEM-131 was found in 1 isolate. Other ESBLs that were identified included SHV-2 (n = 2), CTX-M-3 (n = 1), CTX-M-15 (n = 2), and CTX-M-37 (n = 5). In addition, CMY-2 (n = 3) and the OXA-1(n = 1) beta-lactamase were also detected. The diversity of ESBLs suggests that its incidence in Salmonellae needs to be monitored.