Temocillin Resistance in the Enterobacter cloacae Complex Is Conferred by a Single Point Mutation in BaeS, Leading to Overexpression of the AcrD Efflux Pump.

The Enterobacter cloacae complex (ECC) has become a major opportunistic pathogen with antimicrobial resistance issues. Temocillin, an "old" carboxypenicillin that is remarkably stable toward ß-lactamases, has been used as an alternative for the treatment of multidrug-resistant ECC infections. Here, we aimed at deciphering the never-investigated mechanisms of temocillin resistance acquisition in Enterobacterales. By comparative genomic analysis of two clonally related ECC clinical isolates, one susceptible (Temo_S [MIC of 4 mg/L]) and the other resistant (Temo_R [MIC of 32 mg/L]), we found that they differed by only 14 single-nucleotide polymorphisms, including one nonsynonymous mutation (Thr175Pro) in the two-component system (TCS) sensor histidine kinase BaeS. By site-directed mutagenesis in Escherichia coli CFT073, we demonstrated that this unique change in BaeS was responsible for a significant (16-fold) increase in temocillin MIC. Since the BaeSR TCS regulates the expression of two resistance-nodulation-cell division (RND)-type efflux pumps (namely, AcrD and MdtABCD) in E. coli and Salmonella, we demonstrated by quantitative reverse transcription-PCR that mdtB, baeS, and acrD genes were significantly overexpressed (15-, 11-, and 3-fold, respectively) in Temo_R. To confirm the role of each efflux pump in this mechanism, multicopy plasmids harboring mdtABCD or acrD were introduced into either Temo_S or the reference strain E. cloacae subsp. cloacae ATCC 13047. Interestingly, only the overexpression of acrD conferred a significant increase (from 8- to 16-fold) of the temocillin MIC. Altogether, we have shown that temocillin resistance in the ECC can result from a single BaeS alteration, likely resulting in the permanent phosphorylation of BaeR and leading to AcrD overexpression and temocillin resistance through enhanced active efflux.

Evolution of the incidence of COVID-19 during the first five waves in residents and professionals of nursing homes in Normandy, France.

BACKGROUND: Older adults living in nursing homes (NH) paid a heavy price to the COVID-19 pandemic, despite early and often drastic prevention measures. AIMS: To study the characteristics and the impact of the pandemic on NH residents and professionals over 2 years. METHODS: Cross-sectional study of COVID-19 clusters among residents and/or professionals in NH, from March 2020 to February 2022, in Normandy, France. We used data from the French mandatory reporting system, and cross-correlation analysis. RESULTS: The weekly proportion of NH with clusters was strongly correlated with population incidence (r > 0.70). Attack rates among residents and professionals were significantly lower in period 2 (vaccination rate in residents ≥ 50%) compared with periods 1 (waves 1 and 2) and 3 (Omicron variant ≥ 50%). Among residents, mortality and case fatality rates decreased drastically during periods 2 and 3. CONCLUSION: Our study provides figures on the evolution of the pandemic in NH.

Salmonella enterica subsp. enterica Welikade: guideline for phylogenetic analysis of serovars rarely involved in foodborne outbreaks.

BACKGROUND: Salmonella spp. is a major foodborne pathogen with a wide variety of serovars associated with human cases and food sources. Nevertheless, in Europe a panel of ten serovars is responsible for up to 80% of confirmed human cases. Clustering studies by single nucleotide polymorphism (SNP) core-genome phylogenetic analysis of outbreaks due to these major serovars are simplified by the availability of many complete genomes in the free access databases. This is not the case for outbreaks due to less common serovars, such as Welikade, for which no reference genomes are available. In this study, we propose a method to solve this problem. We propose to perform a core genome MLST (cgMLST) analysis based on hierarchical clustering using the free-access EnteroBase to select the most suitable genome to use as a reference for SNP phylogenetic analysis. In this study, we applied this protocol to a retrospective analysis of a Salmonella enterica serovar Welikade (S. Welikade) foodborne outbreak that occurred in France in 2016. Finally, we compared the cgMLST and SNP analyses. SNP phylogenetic reconstruction was carried out considering the effect of recombination events identified by the ClonalFrameML tool. The accessory genome was also explored by phage content and virulome analyses. RESULTS: Our findings revealed high clustering concordance using cgMLST and SNP analyses. Nevertheless, SNP analysis allowed for better assessment of the genetic distance among strains. The results revealed epidemic clones of S. Welikade circulating within the poultry and dairy sectors in France, responsible for sporadic and non-sporadic human cases between 2012 and 2019. CONCLUSIONS: This study increases knowledge on this poorly described serovar and enriches public genome databases with 42 genomes from human and non-human S. Welikade strains, including the isolate collected in 1956 in Sri Lanka, which gave the name to this serovar. This is the first genomic analysis of an outbreak due to S. Welikade described to date.

Comparison of conventional molecular and whole-genome sequencing methods for subtyping Salmonella enterica serovar Enteritidis strains from Tunisia.

We sought to determine the relative value of conventional molecular methods and whole-genome sequencing (WGS) for subtyping Salmonella enterica serovar Enteritidis recovered from 2000 to 2015 in Tunisia and to investigate the genetic diversity of this serotype. A total of 175 Salmonella Enteritidis isolates were recovered from human, animal, and foodborne outbreak samples. Pulsed-field gel electrophoresis (PFGE), multiple locus variable-number tandem repeat analysis (MLVA), and whole-genome sequencing were performed. Eight pulsotypes were detected for all isolates with PFGE (DI = 0.518). Forty-five Salmonella Enteritidis isolates were selected for the MLVA and WGS techniques. Eighteen MLVA profiles were identified and classified into two major clusters (DI = 0.889). Core genome multilocus typing (cgMLST) analysis revealed 16 profiles (DI = 0.785). Whole-genome analysis indicated 660 single-nucleotide polymorphism (SNP) divergences dividing these isolates into 43 haplotypes (DI = 0.997). The phylogenetic tree supported the classification of Salmonella Enteritidis isolates into two distinct lineages subdivided into five clades and seven subclades. Pairwise SNP differences between the isolates ranged between 302 and 350. We observed about 311 SNP differences between the two foodborne outbreaks, while only less or equal to 4 SNP differences within each outbreak. SNP-based WGS typing showed an excellent discriminatory power comparing with the conventional methods such as PFGE and MLVA. Besides, we demonstrate the added value of WGS as a complementary subtyping method to discriminate outbreak from non-outbreak isolates belonging to common subtypes. It is important to continue the survey of Salmonella Enteritidis lineages in Tunisia using WGS.

ramR Deletion in an Enterobacter hormaechei Isolate as a Consequence of Therapeutic Failure of Key Antibiotics in a Long-Term Hospitalized Patient.

Genome changes are central to the adaptation of bacteria, especially under antibiotic pressure. The aim of this study was to report phenotypic and genomic adaptations undergone by an Enterobacter hormaechei clinical strain that became highly resistant to key antimicrobials during a 4-month period in a patient hospitalized in an intensive care unit (ICU). All six clinical E. hormaechei strains isolated in one ICU-hospitalized patient have been studied. MICs regarding 17 antimicrobial molecules have been measured. Single nucleotide polymorphisms (SNPs) were determined on the sequenced genomes. The expression of genes involved in antibiotic resistance among Enterobacter cloacae complex strains were determined by reverse transcription-quantitative PCR (qRT-PCR). All the strains belonged to sequence type 66 and were distant by a maximum of nine SNPs. After 3 months of hospitalization, three strains presented a significant increase in MICs for ceftazidime, cefepime, temocillin, ertapenem, tigecycline, ciprofloxacin, and chloramphenicol. Those resistant strains did not acquire additional antibiotic resistance genes but harbored a 16-bp deletion in the ramR gene. This deletion led to upregulated expression of RamA, AcrA, AcrB, and TolC and downregulated expression of OmpF. The ΔramR mutant harbored the same phenotype as the resistant clinical strains regarding tigecycline, chloramphenicol, and ciprofloxacin. The increased expression of RamA due to partial deletion in the ramR gene led to a cross-resistance phenotype by an increase of antibiotic efflux through the AcrAB-TolC pump and a decrease of antibiotic permeability by porin OmpF. ramR appears to be an important adaptative trait for E. hormaechei strains.

Meat and Fish as Sources of Extended-Spectrum ß-Lactamase-Producing Escherichia coli, Cambodia.

We compared extended-spectrum ß-lactamase-producing Escherichia coli isolates from meat and fish, gut-colonized women, and infected patients in Cambodia. Nearly half of isolates from women were phylogenetically related to food-origin isolates; a subset had identical multilocus sequence types, extended-spectrum ß-lactamase types, and antimicrobial resistance patterns. Eating sun-dried poultry may be an exposure route.

CTX-M-55-type ESBL-producing Salmonella enterica are emerging among retail meats in Phnom Penh, Cambodia.

Background: Salmonella enterica is a leading cause of human gastroenteritis. S. enterica strains that produce ESBLs (ESBL-Salm) remain rare in Europe and North America, but less is known about their prevalence among animal-derived foods in countries with weaker food safety practices and unregulated veterinary antibiotic use. Objectives: To examine the prevalence and characteristics of ESBL-Salm from retail meats in Phnom Penh, Cambodia. Methods: We tested fish, pork and chicken from two markets for ESBL- and carbapenemase-producing Salmonella from September-December 2016, using cefotaxime- and ertapenem-supplemented media, respectively. ESBL-Salm were sequenced and their genomes characterized. We performed plasmid conjugation experiments to assess the co-transferability of ESBL-encoding genes and MDR phenotypes. Results: Twenty-six of 150 fish and meat samples (17%) were positive for ESBL-Salm, including 10/60 fish (17%), 15/60 pork (25%) and 1/30 chicken (3%). Carbapenemase-producing Salmonella strains were not detected. Pork-origin ESBL-Salm were primarily serotypes Rissen (10/15) or a monophasic variant of Typhimurium 4,5,12:i:- (3/15), whereas Saintpaul (3/10) and Newport (4/10) were more common among fish. Most ESBL enzymes were encoded by blaCTX-M-55 genes (24/26) harboured on conjugative IncA/C2 (n = 14) or IncHI2 (n = 10) plasmids. Resistance to up to six additional drug classes was co-transferred by each plasmid type. ESBL-Salm were resistant to almost every antibiotic recommended for severe salmonellosis treatment. Conclusions: CTX-M-55-type S. enterica are highly prevalent among pork and fish from Phnom Penh markets and their spread appears to be mediated by MDR IncA/C2 and IncHI2 plasmids. Food safety must be improved and veterinary antibiotic use should be regulated to protect public health.

Evaluation of temocillin for phenotypic carbapenemase screening of Escherichia coli and Salmonella enterica isolates in relation to the presence of genes encoding ESBLs and carbapenemase production.

BACKGROUND: The expression of enzymes of the OXA-48 carbapenemase group is difficult to detect by phenotypic methods owing to frequent low levels of carbapenem resistance and negative results with some screening methods. Temocillin has been shown to be a good option for phenotypic screening as it is hydrolysed by the OXA-48-group enzymes, whereas ESBLs, AmpC and some other carbapenemases have a lower hydrolytic effect on this antimicrobial. However, no epidemiological cut-off for temocillin is available. OBJECTIVES: To evaluate temocillin MICs in relation to the presence or absence of genes encoding ESBLs and carbapenemases in Escherichia coli and Salmonella enterica. METHODS: In this study, 111 E. coli and 102 S. enterica isolates, including WT and well-characterized ESBL-, AmpC- or carbapenemase-producing isolates, were tested by three independent laboratories. MICs were determined according to the CLSI guidelines by agar dilution with the test range from 0.5 to 512 mg/L temocillin and WGS was performed and analysed with ResFinder. RESULTS: Some overlap was detected between temocillin MICs for WT and ESBL- or AmpC-producing isolates. However, isolates carrying genes encoding carbapenemases showed a broader range of MICs for both E. coli and S. enterica. Higher MICs were observed for the OXA-48 group, VIM and some NDM-producing isolates, whereas isolates harbouring KPC enzymes showed low MICs. CONCLUSIONS: The results indicate that temocillin MICs enable phenotypic distinction between strains producing OXA-48-group enzymes and both WT susceptible and ESBL/AmpC-carrying isolates, whereas the distinction from other carbapenemases likely requires genotypic testing.

Rapid and Simple Universal Escherichia coli Genotyping Method Based on Multiple-Locus Variable-Number Tandem-Repeat Analysis Using Single-Tube Multiplex PCR and Standard Gel Electrophoresis.

We developed a multiplex PCR method based on multiple-locus variable-number tandem-repeat (VNTR) analysis (MLVA) that was designed for the rapid typing of Escherichia coli and Shigella isolates. The method amplifies seven VNTRs and does not require a sequencing capillary or fluorescent dyes. The amplification products are simply loaded on a standard agarose gel for electrophoresis, and the banding patterns are analyzed visually. We evaluated the method on 220 strains belonging to different collections: the E. coli reference (ECOR) collection (n = 72), O1:K1 isolates causing neonatal meningitis (n = 38), extended-spectrum beta-lactamase-producing fecal isolates belonging to the worldwide sequence type 131 (ST131) clone (n = 38), Shiga toxin-producing E. coli (STEC) isolates of serogroups O157:H7 (n = 21) and O26 (n = 16, 8 of which belonged to an outbreak), 27 Shigella isolates (22 Shigella sonnei isolates, including 5 epidemic strains), and 8 reference strains. The performances were compared to those of multilocus sequence typing (MLST), the DiversiLab automated repetitive element palindromic PCR (REP-PCR), pulsed-field gel electrophoresis (PFGE), and whole-genome sequencing (WGS). We found 66 different profiles among the isolates in the ECOR collection. Among the clonal group O1:K1 isolates, 14 different profiles were identified. For the 37 STEC isolates, we found 23 profiles, with 1 corresponding to the 8 epidemic strains. We found 19 profiles among the 27 Shigella isolates, with 1 corresponding to the epidemic strain. The method was able to recognize strains of the ST131 clone and to distinguish the O16 and O25b serogroups and identified 15 different MLVA types among them. This method allows the simple, fast, and inexpensive typing of E. coli/Shigella isolates that can be carried out in any laboratory equipped for molecular biology and has a discriminatory power superior to that of MLST and DiversiLab REP-PCR but slightly lower than that of PFGE.IMPORTANCE Fast typing methods that can easily and accurately distinguish clonal groups and unrelated isolates are of particular interest for microbiologists confronted with outbreaks or performing epidemiological studies. Highly discriminatory universal methods, like PFGE, optical mapping, or WGS, are expensive and/or time-consuming. MLST is useful for phylogeny but is less discriminatory and requires sequencing facilities. PCR methods, which are fast and easy to perform, also have drawbacks. Random PCRs and REP-PCR are universal but lack reproducibility. Other PCR methods may lack the discriminatory power to differentiate isolates during outbreaks. MLVA combines the advantages of PCR methods with a high discriminatory power but in its standard form requires sequencing capillary electrophoresis. The method that we have developed combines the advantages of standard PCR (simple, fast, and inexpensive) with the high discriminatory power of MLVA and permits the typing of all E. coli isolates (either intestinal or extraintestinal pathogenic isolates as well as commensal isolates).

Paediatric haemolytic uraemic syndrome related to Shiga toxin-producing Escherichia coli, an overview of 10 years of surveillance in France, 2007 to 2016.

IntroductionHaemolytic uraemic syndrome (HUS) related to Shiga toxin-producing Escherichia coli (STEC) is the leading cause of acute renal failure in young children. In France, HUS surveillance in children aged < 15 years was implemented starting from 1996.AimWe present the results of this surveillance between 2007 and 2016.MethodsA voluntary nationwide network of 32 paediatric departments notifies cases. Two national reference centres perform microbiological STEC confirmation.ResultsOver the study period, the paediatric HUS incidence rate (IR) was 1.0 per 100,000 children-years, with a median of 116 cases/year. In 2011, IR peaked at 1.3 per 100,000 children-years, and decreased to 1.0 per 100,000 children-years in 2016. STEC O157 associated HUS peaked at 37 cases in 2011 and decreased to seven cases in 2016. Cases of STEC O26-associated HUS have increased since 2010 and STEC O80 associated HUS has emerged since 2012, with 28 and 18 cases respectively reported in 2016. Four STEC-HUS food-borne outbreaks were detected (three STEC O157 linked to ground beef and raw-milk cheese and one STEC O104 linked to fenugreek sprouts). In addition, two outbreaks related to person-to-person transmission occurred in distinct kindergartens (STEC O111 and O26).ConclusionsNo major changes in HUS IRs were observed over the study period of 10 years. However, changes in the STEC serogroups over time and the outbreaks detected argue for continuing epidemiological and microbiological surveillance.

Disentangling a complex nationwide Salmonella Dublin outbreak associated with raw-milk cheese consumption, France, 2015 to 2016.

On 18 January 2016, the French National Reference Centre for Salmonella reported to Santé publique France an excess of Salmonella enterica serotype Dublin (S. Dublin) infections. We investigated to identify the source of infection and implement control measures. Whole genome sequencing (WGS) and multilocus variable-number tandem repeat analysis (MLVA) were performed to identify microbiological clusters and links among cases, animal and food sources. Clusters were defined as isolates with less than 15 single nucleotide polymorphisms determined by WGS and/or with identical MLVA pattern. We compared different clusters of cases with other cases (case-case study) and controls recruited from a web-based cohort (case-control study) in terms of food consumption. We interviewed 63/83 (76%) cases; 2,914 controls completed a questionnaire. Both studies' findings indicated that successive S. Dublin outbreaks from different sources had occurred between November 2015 and March 2016. In the case-control study, cases of distinct WGS clusters were more likely to have consumed Morbier (adjusted odds ratio (aOR): 14; 95% confidence interval (CI): 4.8-42) or Vacherin Mont d'Or (aOR: 27; 95% CI: 6.8-105), two bovine raw-milk cheeses. Based on these results, the Ministry of Agriculture launched a reinforced control plan for processing plants of raw-milk cheeses in the production region, to prevent future outbreaks.

In-Host Adaptation of Salmonella enterica Serotype Dublin during Prosthetic Hip Joint Infection.

Genome degradation has been central to the adaptation of Salmonella enterica serotypes to their hosts throughout evolution. We witnessed the patho-adaptation of a strain of Salmonella Dublin (a cattle-adapted serotype) to a human host during the course of a recurrent prosthetic hip joint infection evolving over several years.

Ongoing nationwide outbreak of Salmonella Agona associated with internationally distributed infant milk products, France, December 2017.

On 1 December 2017, an outbreak of Salmonella Agona infections among infants was identified in France. To date, 37 cases (median age: 4 months) and two further international cases have been confirmed. Five different infant milk products manufactured at one facility were implicated. On 2 and 10 December, the company recalled the implicated products; on 22 December, all products processed at the facility since February 2017. Trace-forward investigations indicated product distribution to 66 countries.

The invasome of Salmonella Dublin as revealed by whole genome sequencing.

BACKGROUND: Salmonella enterica serovar Dublin is a zoonotic infection that can be transmitted from cattle to humans through consumption of contaminated milk and milk products. Outbreaks of human infections by S. Dublin have been reported in several countries including high-income countries. A high proportion of S. Dublin cases in humans are associated with invasive disease and systemic illness. The genetic basis of virulence in S. Dublin is not well characterized. METHODS: Whole genome sequencing was applied to a set of clinical invasive and non-invasive S. Dublin isolates from different countries in order to characterize the putative genetic determinants involved in the virulence and invasiveness of S. Dublin in humans. RESULTS: We identified several virulence factors that form the bacterial invasome and may contribute to increasing bacterial virulence and pathogenicity including mainly Gifsy-2 prophage, two different type 6 secretion systems (T6SSs) harbored by Salmonella pathogenicity islands; SPI-6 and SPI-19 respectively and virulence genes; ggt and PagN. Although Vi antigen and the virulence plasmid have been reported previously to contribute to the virulence of S. Dublin we did not detect them in all invasive isolates indicating that they are not the main virulence determinants in S. Dublin. CONCLUSION: Several virulence factors within the genome of S. Dublin might contribute to the ability of S. Dublin to invade humans' blood but there were no genomic markers that differentiate invasive from non-invasive isolates suggesting that host immune response play a crucial role in the clinical outcome of S. Dublin infection.

Multi-laboratory validation study of multilocus variable-number tandem repeat analysis (MLVA) for Salmonella enterica serovar Enteritidis, 2015.

Multilocus variable-number tandem repeat analysis (MLVA) is a rapid and reproducible typing method that is an important tool for investigation, as well as detection, of national and multinational outbreaks of a range of food-borne pathogens. Salmonella enterica serovar Enteritidis is the most common Salmonella serovar associated with human salmonellosis in the European Union/European Economic Area and North America. Fourteen laboratories from 13 countries in Europe and North America participated in a validation study for MLVA of S. Enteritidis targeting five loci. Following normalisation of fragment sizes using a set of reference strains, a blinded set of 24 strains with known allele sizes was analysed by each participant. The S. Enteritidis 5-loci MLVA protocol was shown to produce internationally comparable results as more than 90% of the participants reported less than 5% discrepant MLVA profiles. All 14 participating laboratories performed well, even those where experience with this typing method was limited. The raw fragment length data were consistent throughout, and the inter-laboratory validation helped to standardise the conversion of raw data to repeat numbers with at least two countries updating their internal procedures. However, differences in assigned MLVA profiles remain between well-established protocols and should be taken into account when exchanging data.

Multinational outbreak of travel-related Salmonella Chester infections in Europe, summers 2014 and 2015.

Between 2014 and 2015, the European Centre for Disease Prevention and Control was informed of an increase in numbers of Salmonella enterica serotype Chester cases with travel to Morocco occurring in six European countries. Epidemiological and microbiological investigations were conducted. In addition to gathering information on the characteristics of cases from the different countries in 2014, the epidemiological investigation comprised a matched case-case study involving French patients with salmonellosis who travelled to Morocco that year. A univariate conditional logistic regression was performed to quantify associations. The microbiological study included a whole genome sequencing (WGS) analysis of clinical and non-human isolates of S. Chester of varied place and year of isolation. A total of 162 cases, mostly from France, followed by Belgium, the Netherlands, Spain, Denmark and Sweden were reported, including 86 (53%) women. The median age per country ranged from 3 to 38 years. Cases of S. Chester were more likely to have eaten in a restaurant and visited the coast of Morocco. The results of WGS showed five multilocus sequence types (ST), with 96 of 153 isolates analysed clustering into a tight group that corresponded to a novel ST, ST1954. Of these 96 isolates, 46 (48%) were derived from food or patients returning from Morocco and carried two types of plasmids containing either qnrS1 or qnrB19 genes. This European-wide outbreak associated with travel to Morocco was likely a multi-source outbreak with several food vehicles contaminated by multidrug-resistant S. Chester strains.

Global Genomic Epidemiology of Salmonella enterica Serovar Typhimurium DT104.

It has been 30 years since the initial emergence and subsequent rapid global spread of multidrug-resistant Salmonella entericaserovar Typhimurium DT104 (MDR DT104). Nonetheless, its origin and transmission route have never been revealed. We used whole-genome sequencing (WGS) and temporally structured sequence analysis within a Bayesian framework to reconstruct temporal and spatial phylogenetic trees and estimate the rates of mutation and divergence times of 315S Typhimurium DT104 isolates sampled from 1969 to 2012 from 21 countries on six continents. DT104 was estimated to have emerged initially as antimicrobial susceptible in ∼1948 (95% credible interval [CI], 1934 to 1962) and later became MDR DT104 in ∼1972 (95% CI, 1972 to 1988) through horizontal transfer of the 13-kb Salmonella genomic island 1 (SGI1) MDR region into susceptible strains already containing SGI1. This was followed by multiple transmission events, initially from central Europe and later between several European countries. An independent transmission to the United States and another to Japan occurred, and from there MDR DT104 was probably transmitted to Taiwan and Canada. An independent acquisition of resistance genes took place in Thailand in ∼1975 (95% CI, 1975 to 1990). In Denmark, WGS analysis provided evidence for transmission of the organism between herds of animals. Interestingly, the demographic history of Danish MDR DT104 provided evidence for the success of the program to eradicate Salmonellafrom pig herds in Denmark from 1996 to 2000. The results from this study refute several hypotheses on the evolution of DT104 and suggest that WGS may be useful in monitoring emerging clones and devising strategies for prevention of Salmonella infections.

Outbreak of Salmonella Enteritidis linked to the consumption of frozen beefburgers received from a food bank and originating from Poland: northern France, December 2014 to April 2015.

A prolonged outbreak of Salmonella enterica serotype Enteritidis occurred in northern France between December 2014 and April 2015. Epidemiological investigations following the initial notification on 30 December 2014 of five cases of salmonellosis (two confirmed S. Enteritidis) in young children residing in the Somme department revealed that all cases frequented the same food bank A. Further epidemiological, microbiological and food trace-back investigations indicated frozen beefburgers as the source of the outbreak and the suspected lot originating from Poland was recalled on 22 January 2015. On 2 March 2015 a second notification of S. Enteritidis cases in the Somme reinitiated investigations that confirmed a link with food bank A and with consumption of frozen beefburgers from the same Polish producer. In the face of a possible persistent source of contamination, all frozen beefburgers distributed by food bank A and from the same origin were blocked on 3 March 2015. Microbiological analyses confirmed contamination by S. Enteritidis of frozen beefburgers from a second lot remaining in cases' homes. A second recall was initiated on 6 March 2015 and all frozen beefburgers from the Polish producer remain blocked after analyses identified additional contaminated lots over several months of production.

Salmonella enterica serotype enteritidis in French Polynesia, South Pacific, 2008-2013.

Outbreaks of Salmonella enterica serotype Enteritidis infections associated with eggs occurred in French Polynesia during 2008-2013. Molecular analysis of isolates by using clustered regularly interspaced short palindromic repeat polymorphisms and multilocus variable-number tandem-repeat analysis was performed. This subtyping made defining the epidemic strain, finding the source, and decontaminating affected poultry flocks possible.

Multidrug-resistant Salmonella enterica serotype Typhi, Gulf of Guinea Region, Africa.

We identified 3 lineages among multidrug-resistant (MDR) Salmonella enterica serotype Typhi isolates in the Gulf of Guinea region in Africa during the 2000s. However, the MDR H58 haplotype, which predominates in southern Asia and Kenya, was not identified. MDR quinolone-susceptible isolates contained a 190-kb incHI1 pST2 plasmid or a 50-kb incN pST3 plasmid.