National and Regional projects​

​Shigella in Thailand project

​A total of 9,063 Shigella isolates obtained from different medical centers in Thailand in the period 1993 through 2006 were serotyped and the trends over time and spatial clustering analyzed. The study shows that when looking at the Shigella species Thailand changed from being a developing country to a developed country between 1995 and 1996. In addition, major shifts in the types of S. sonnei causing infections in humans in Thailand were observed as were differences in the spatial clustering of S. flexneri and S. sonnei and serotypes of S. flexneri. These aspects need further studies.

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Reference:​Bangtrakulnonth A, Lo Fo Wong D , Viera A, Pornreongwong S, Pulsrikarn C, Sawanpanyalert P, Hendriksen RS, Aarestrup FM, 2008. Shigella from humans in Thailand during 1993 to 2006: spatial-time trends in species and serotype distribution. Foodborne Pathog Dis. 2008.

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Salmonella in Henan province, China project

The study was conducted to determine the occurrence of different Salmonella serovars and their antimicrobial susceptibility among isolates obtained from human infections in Henan province,​China. In addition, the molecular types of the most common serovars were determined.

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Reference: Xia S, Hendriksen RS, Xie Z, Xu B, Guo W,​Lu R, Aarestrup FM. Serotypes, antimicrobial susceptibility and molecular characterization of Salmonella from infections in humans in Henan province, China. J. Clin. Microbiol.​

2006

​The Nepal project II

​Aims: To study occurrence and diversity of Salmonella serovars in urban water supply systems of Nepal.

Methods and Results: Occurrence of Salmonella was detected in 42 out of 300 water samples by enrichment culture technique in selenite F broth followed by plating on Salmonella Shigella agar. Total 54 isolates identified to genus level by standard tests were subsequently confirmed by serotyping, phage typing and PCR detection of virulence genes (inv A and spv C). Predominant serotype was Salmonella Typhimurium, followed by Salm. Typhi, Salm. Paratyphi A and Salmonella Enteritidis. Most of the Salm. Typhi isolates were E1 phage type followed by UVS4, A and UVS1. All isolates of Salm. Paratyphi A and Salm. Enteritidis were an untypable (UT) phage type. Majority of isolates were multidrug resistant as revealed by Kirby–Bauer disc diffusion technique. Ceftriaxone resistant isolates of Salm. Enteritidis indicated presence of one of the ESBL genes, blaSHV, whereas, the genes blaTEM and blaCTX were absent.

Conclusions: Microbiological quality of urban water supply is poor and indicates possibility of fatal outbreaks of enteric fever and related infections in Nepal. Significance and Impact of the Study: Present study will be useful in water borne diseases control and prevention strategy formulation in Nepal and in the global context.

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Reference: Bhatta DR, Bangtrakulnonth A, Tishyadhigama P, Saroj SD, Bandekar JR, Hendriksen RS, Kapadnis BP, 2007. Serotyping, PCR, phage-typing and antibiotic sensitivity testing of Salmonella serovars isolated from urban drinking water supply systems of Nepal. Lett Appl Microbiol. 44(6):588-94.

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The Monophasic Goettingen project

We examined 22 monophasic Salmonella 9,12:l,v:- and 17 diphasic 9,12:l,v isolates from humans, animals and food products in Bulgaria, Denmark, and the United States by serotyping and antimicrobial susceptibility testing. In addition, all strains were characterized by Pulsed Field Gel Electrophoresis (PFGE). All of the monophasic isolates were examined for presence of the fljB gene by PCR and 10 of them sequenced. Most of the monophasic isolates were almost fully susceptible to all antimicrobials tested whereas the diphasic Panama strains from Denmark were multiresistant. A total of four different PFGE patterns were observed among the monophasic Salmonella isolates when digested with XbaI. Pattern TEBX01.0001DK included isolates from both Bulgaria and Denmark whereas patterns TEBX01.0002DK and TEBX01.0004DK only were present in isolates from Denmark. Pattern TEBX01.0003DK was only observed in the strain from the United States. The patterns of the monophasic strains showed most relatedness to Salmonella Goettingen isolates compared to other diphasic 9,12:l,v isolates. All the monophasic isolates were positive for the fljB gene in PCR and sequencing of 10 strains revealed perfect match with the e,n,z15 group.

The study indicate that all of the Salmonella 9,12:l,v:- serovar investigated was of a monophasic variant of Salmonella Goettingen and are present in different countries and on different continents.

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Reference:​Petrov P, Hendriksen RS, Kantardjiev T, Asseva G, Sørensen G, Fields P, Mikoleit M, Whichard J, McQuiston JR, Angulo F, Aarestrup FM. Occurrence and Characterization of Salmonella enterica subspecies enterica serovar 9,12:l,v:- strains from Bulgaria, Denmark and the United States. European Journal of Clinical Microbiology & Infectious Diseases.

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The Nigeria project

The project focuses on the bacteriological and serological studies on Salmonella serovars in chicken meat in Nigeria. Two unique PFGE patterns were observed among the 35 S. Hiduddify isolates when digested with XbaI (Figure 1). The most common XbaI pattern included 33 isolates whereas the other XbaI pattern was given to only two of the isolates - #24 and #B4.

Analysis of the S. Hiduddify isolates using the composite data set of XbaI and the MIC results in combination revealed that the discrimination power was higher subdividing the S. Hiduddify isolates into eight types (Figure 1). Isolate #24 belonging to type VIII showed an unique MIC profile but shared the PFGE pattern with isolate #B4 belonging to type V. Isolate #24 have the same MIC profile (POD and CEP) as five other isolates.

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Reference: Raufu I, Hendriksen RS, Aarestrup FM, 2008. Antimicrobial resistance and molecular epidemiology of Salmonella Hiduddify from chickens in Nigeria. Foodborne Pathog Dis.

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The Salmonella ​Concord project

This study shows how international collaboration and sharing of information, even of potentially rare or isolated cases, can lead to the identification of a larger problem affecting the global community.

In addition, this is the first study to describe the spread of multidrug resistant Salmonella​ Concord in Europe and the United States of America among children adopted from Ethiopia. The outcome of this study suggests that multidrug resistant Salmonella​ Concord clones circulating among Ethiopian adoptee are distinct from other Salmonella​ Concord clones circulating in Africa. Based on the incident rate of infected Ethiopian adoptees from Denmark, we estimate that there could potentially be an estimated 52,000 orphans in Ethiopia infected with multidrug resistant Salmonella​ Concord.

The number of PFGE types observed suggests that Salmonella​ Concord may be a common and genetically diverse serovar in the region with an unknown reservoir(s). Further studies are needed to identify these reservoir(s). We feel it is essential to elucidate this problem so that intervention and prevention measures may be implemented for the benefit of the adoptees and the global community.

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Reference:​Hendriksen RS, Mikoleit M, Kornschober C, Rickert, R, Van Duyne MS, Kjelsø C, Hasman H, Cormican M, Mevius D, Threlfall EJ, Valinsky L, Angulo FJ,​Aarestrup FM, 2008. Emergence of multidrug-resistant Salmonella​ Concord infections in Europe and the United States in children adopted from Ethiopia, 2003-2007.

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Salmonella in Chickens from Turkey project

Salmonella Enteritis from poultry products in Turkey were characterized and the data analyzed. A widespread occurrence of resistance was observed among some of the isolates, but not related to specific molecular types.

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Reference: Kalender H, Şen S, Hasman H, Hendriksen RS, Aarestrup FM. Antimicrobial susceptibilities, Phage Types and Molecular Characterization of Salmonella enterica Serovar Enteritidis from Chickens and Chicken Meat in Turkey. Foodborne Pathog Dis.

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Salmonella in Brazil project

The occurrence of antimicrobial resistance genes and role of integrons among 135 antimicrobial-resistant Salmonella enterica from Brazil were determined. A widespread occurrence of resistance was observed and some new combinations of antimicrobial resistance genes found. Furthermore a novel trimethoprim resistance gene, drrA25 was identified and cloned.

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Reference:​Peirano G, Agersø Y, Aarestrup FM, dos Reis EM, dos Prazeres Rodrigues D. Occurrence of integrons and antimicrobial resistance genes among Salmonella enterica from Brazil. J Antimicrob Chemother. 2006 Aug;58(2):305-9.

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Reference:​Agersø Y, Peirano G, Aarestrup FM. dfrA25, a novel trimethoprim resistance gene from Salmonella Agona isolated from a human urine sample in Brazil. J Antimicrob Chemother. 2006 Nov;58(5):1044-7.

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Shigella in Brazil project

The occurrence of antimicrobial resistance and most common resistance genes were determined among 62 Shigella isolates from Brazil.

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Reference: Peirano G, Agersø Y, Aarestrup FM, dos Prazeres Rodrigues D. Occurrence of integrons and resistance genes among sulphonamide-resistant Shigella spp. from Brazil. J Antimicrob Chemother. 2005 Mar;55(3):301-5

2005

​The Columbia project

​From 2004 to 2005, 55 isolates were serotyped for the School of Veterinary Medicine and Animal Husbandry at the University of Antioquia in Medellín, Colombia.​Serotypes were intended to assist in producing important epidemiological information as part of the “Prevalence, biotype and serotype of Salmonella​spp. in flocks and commercials layers in the Antioquia region” Study.​It was estimated that the project would provide important epidemiological information to Columbia.

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Reference: No data has been published.

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Democratic Republic of the Congo project

Salmonella serotyping and antimicrobial susceptibility testing were performed on 28 isolates sent to the Danish Institute for Food and Veterinary Research in 2002.​A poster presentation of the project was submitted and accepted at the 15th European Congress of Clinical Microbiology and Infectious Diseases in Copenhagen, Denmark in 2005.

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Reference: ​2008. Antimicrobial Susceptibility of Bacterial Enteric Pathogens Isolated in Humans from 2002 to 2004 in the Province of South–Kivu, Democratic Republic of Congo,

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Reference:​Microbiological and clinical features of Salmonella species isolated from bacteremic children in eastern Democratic republic of Congo.

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Nepal project I

In 2005, Salmonella serotyping was performed on 65 strains from drinking water and clinical samples from Kathmandu, Nepal. Twenty-nine of the 65 strains were found to be Typhi; eight of the 65 strains were identified as Paratyphi A.

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Reference: An abstract on the project was accepted for presentation at the WHO Sixth International Conference of Typhoid Fever and other Salmonellosis, Guilin, China, 12-14 November 2005.

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The Sudanese project

In 2005, Salmonella​serotyping was conducted on 40 isolates from Sudan. Data will be used for the thesis, “Genetic Analysis of Salmonella spp. isolated from Humans and Other Sources in Sudan”.

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Reference: No data has been published.

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The Salmonella ​Krefeld project

In 2005, assistance on minimum inhibitory concentration (MIC) determinations and pulse field gel electrophoresis on 11 isolates of S. Krefeld was provided for the Salmonella Reference Laboratory at the Institute of Public Health of Serbia. The project analyzes the first isolates of S. Krefeld from human and food origin in Serbia.

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Reference: Grego E, Galić N, Hendriksen RS, Aarestrup FM, 2007. Salmonella​ Krefeld isolates in Serbia. 5th Balkan Congress for Microbiology, 24-27 Oct. 2007, Budva, Montenegro.

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Poultry isolates from Kuwait project

The prevalence of Salmonella isolated from a poultry farm and from the poultry processing plant environment were evaluated from August 2004 to July 2005 along with microbial antibiotic resistance. In total, 3242 samples were collected from the farm and processing plant. Samples collected from the farm included hatching eggs, paper liners, litter, feed, water, drinkers, air, bird rinse, and ceca. Salmonella Enteritidis was the most prevalent serotype. All of the isolates were resistant to at least one antibiotic and 10 different resistance profiles were found among 173 isolates of Salmonella Enteritidis. Resistance to ampicillin, nalidixic acid, and tetracycline were the most common. The widespread occurrence of multiple resistant Salmonella Enteritidis is a cause for concern, and local regulatory enforcement agencies should ensure prudent use of antibiotics.

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Reference: Al-Zenki S, Al-Nasser A, Al-Safar A, Alomirah H, Al-Haddad A, Hendriksen RS, Aarestrup FM, 2007. Prevalence and antibiotic resistance of Salmonella isolated from a poultry farm and processing plant environment in the State of Kuwait. Foodborne Pathog Dis. 4(3):367-73.

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The Salmonella Rissen project

The objective of this study was to determine the clonality, molecular variation, occurrence of antimicrobial resistance and the presence of resistance genes of S. Rissen from humans, food products and animals in Denmark and in Thailand.

The risk factors due to global spread because of travel and consumption of imported food products were analyzed and evaluated statistically and biologically.

We compared a total of 112 S. Rissen isolated from patients, “raw food” and “ready to eat food” from Thailand and patients from Denmark with and without a history of travel to Thailand prior to the infection, Danish pig/pork, Spanish imported pig/pork, turkeys and animal feed.

A total of 63 unique PFGE XbaI patterns were observed with pattern TEEX01.0017.DK as the most predominant (N = 22). The level of resistance was low in strains originating from Denmark whereas more resistance was observed in strains from Thailand. Almost all isolates were resistant to tetracycline encoding by the tetA gene whereas the isolates from Danish turkey and animal feed were almost fully susceptible to all antimicrobials tested.

The statistical and molecular analysis supports that Danish patients become infected from a combination of travelling to Thailand and by consumption of imported pig / pork as well as pig / pork produced in Denmark. The outcome of this study might be used as a supplement for future S. Rissen investigations and outbreak detection.

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Reference: Hendriksen RS, Bangtrakulnonth A, Pulsrikarn C, Pornreongwong S, Hasman H, Song SW, Aarestrup FM. Antimicrobial Resistance and Molecular Epidemiology of Salmonella Rissen from Animals, Food Products, and Patients in Thailand and Denmark. Foodborne Pathog Dis. 2008 Aug 

2004​

​The Salmonella Schwarzengrund project

​Serotype Schwarzengrund was noted as an emergent serotype in Asia, as well as, some Western nations​in the WHO Global Salm-Surv publication “Salmonella serovars from humans and other sources in Thailand, 1993-2002. Emerg Infect Dis. 2004 Jan;10(1):131-6.”​From 2004 to 2005, 314 isolates from Asia, Europe, and North America were collected and investigated at the Danish Institute for Food and Veterinary Research. Investigation into Salmonella Schwarzengrund suggested that trade and foreign travel were related to its emergence.

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Reference: Aarestrup FM, Hendriksen RS, Lockett J, Gay K, Teates K, McDermott PF, White DG, Hasman H, Sørensen G, Bangtrakulnonth A, Pornreongwong S, Pulsrikarn C, Angulo FJ, Gerner-Smidt P. International spread of multidrug-resistant Salmonella Schwarzengrund in food products. Emerg Infect Dis. 2007 May;13(5):726-31.

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The Salmonella​ Corvallis project

Hospital infections,​extended-spectrum beta-lactamase resistance producing strains containing the gene SHV 2, and its rank as the third most reported serotype among humans in Bulgaria for a number of years made Salmonella ​Corvallis a pathogen of interest for reference testing at the Danish Institute for Food and Veterinary Research in 2004.​A comparison between 243 Corvallis strains collected from Bulgaria, Thailand, and Denmark was conducted. The poster “Molecular characterization and occurrence of extended-spectrum beta-lactamase resistance genes among Salmonella enterica serovar Corvallis from Thailand, Bulgaria and Denmark“ was presented at the Agriculture's Role in Managing Antimicrobial Resistance Conference in Toronto, 2005.

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Reference: Archambault M, Petrov P, Hendriksen RS, Asseva G, Bangtrakulnonth A, Hasman H, Aarestrup FM. Molecular characterization and occurrence of extended-spectrum beta-lactamase resistance genes among Salmonella enterica serovar Corvallis from Thailand, Bulgaria, and Denmark. Microb Drug Resist. 2006 Fall;12(3):192-8.

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The Belarus project

A high incidence of salmonellosis in young children from the region of Gomel, Belarus was reported to the Danish Institute for Food and Veterinary Research in 2004. After investigating 35 strains, results suggested a spread of very closely related clones based on pulse field gel electrophoresis and multilocus variable-number tandem-repeat analysis (MLVA) typing. These strains were highly resistant and contained the CTX-M15 gene.

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Reference:​Results were presented at the Republican Conference on Infectious Diseases in May 2005 in​Gomel, Belarus.

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Reference: Tapalski D, Hendriksen RS, Hasman H, Ahrens P, Aarestrup FM, 2007. Molecular characterisation of multidrug-resistant Salmonella enterica serovar Typhimurium isolates from Gomel region, Belarus. Clin Microbiol Infect. 13(10):1030-3.

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The Thailand​ Campylobacter project

In 2004, assistance to determine the minimum inhibitory concentration (MIC) in 50 isolates of Campylobacter spp. was requested by a WHO Global Salm-Surv member from the Armed Forces Research Institute of Medical Sciences (AFRIMS) in Thailand. Strains were tested using agar dilution against chloramphenicol, streptomycin, gentamicin, tetracycline, azithromycin, erythromycin, nalidixic acid and ciprofloxacin. All isolates were somewhat resistant against streptomycin, tetracycline, azithromycin, erythromycin, nalidixic acid and ciprofloxacin.

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Reference: No data has been published

2003

​Salmonella lamphun project

​Two isolates of a new Salmonella serovar, Salmonella Lamphun were discovered from animal feeds in Thailand, in 2003, which belongs to group C, with antigenic formula 6,8:y: 1,2. Both isolates were susceptible to all antimicrobials tested.

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Reference: Kusum M, Bangtrakulnonth A, Pulsrikarn C, Aarestrup FM. Salmonella lamphun: first isolation of a new Salmonella serovar in Thailand. Southeast Asian J Trop Med Public Health. 2006;37 Suppl 3:149-52.

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The Taiwan, China, Surveillance programme of Antimicrobial Resistance

Salmonella serotyping was performed on 799 isolates collected from Taiwan, China, Surveillance of Antimicrobial Resistance from 1998 to 2002. As a result of this project, Salmonella Schwarzengrund and Salmonella Cholerasuis were identified as two of the most common serotypes unique to Taiwan, China. The results were presented on a poster at the National Health Research Institutes 10th Anniversary and Campus Grand Opening Program and Abstracts in 2005.

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Reference: Lauderdale TL, Aarestrup FM, Chen PC, Lai JF, Wang HY, Shiau YR, Huang IW, Hung CL; TSAR hospitals, 2006. Multidrug resistance among different serotypes of clinical Salmonella isolates in Taiwan. Diagn Microbiol Infect Dis. 55(2):149-55.​

2002

​The Thailand​Salmonella serovar project

​Serotype data from 44,087 Salmonella isolates from humans and 26,148 from other sources from 1993 through 2002 in​Thailand were analyzed. The most common serovar causing human salmonellosis in Thailand was Salmonella enterica Weltevreden. Serovars causing human infections in Thailand differ from those in other countries and seem to be related to Salmonella serovars in different food products and reservoirs.

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Reference: Bangtrakulnonth A, Pornreongwong S, Pulsrikarn C, Sawanpanyalert P, Hendriksen RS, Lo Fo Wong DM, Aarestrup FM. Salmonella serovars from humans and other sources in Thailand, 1993-2002. Emerg Infect Dis. 2004 Jan;10(1):131-6.

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The Thailand phage typing project

In 2002, The WHO National Salmonella and Shigella​Center, Department of Medical Science in Thailand, requested the Danish Institute for Food and Veterinary Research to phage type 79 Salmonella​ Typhimurium strains of human and animal origin during 2000-2001. Phage typing was performed to gain a better understanding of the prevalence of the different phage types of Typhimurium present in Thailand.

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Reference: No data has been published.​

2001

The Salmonella Weltevreden project

As a result of presentations and discussions of Salmonella serotypes at the Level II-Advanced Course for Microbiologists in Thailand in 2001, Salmonella Weltevreden was identified as a regional serotype of concern and interest.​Consequently, a regional project was launched among countries from the course to further investigate this serotype. A total of 413 isolates from Southeast Asia and Western Pacific regions were collected and investigated.

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Reference: Aarestrup FM, Lertworapreecha M, Evans MC, Bangtrakulnonth A, Chalermchaikit T, Hendriksen RS, Wegener HC. Antimicrobial susceptibility and occurrence of resistance genes among Salmonella enterica serovar Weltevreden from different countries. J Antimicrob Chemother. 2003 Oct;52(4):715-8. Epub 2003 Sep 12.