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.
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.
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.
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.
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.
Reference: Raufu I, Hendriksen RS, Aarestrup FM, 2008. Antimicrobial resistance and molecular epidemiology of Salmonella Hiduddify from chickens in Nigeria. Foodborne Pathog Dis.
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.
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.
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.
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.
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.
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.
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.
Shigella in Brazil project
The occurrence of antimicrobial resistance and most common resistance genes were determined among 62 Shigella isolates from Brazil.
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