salmonellosis due to nontyphoidal salmonella ( nts ) infection is a global public health concern , particularly in salmonella endemic low and middle income countries ( lmics ) . treatment is critical for persons with severe disease , particularly children and immune compromised people . treatment with an appropriate antibiotic can shorten the duration of symptoms , significantly reduce severity of disease and the risk of transmission , and prevent potentially lethal complications . emergence of resistance to first - line therapy like ampicillin , chloramphenicol , and cotrimoxazole including ciprofloxacin among salmonella spp . during the last decades has complicated the situation [ 1 , 2 ] . for treatment of salmonella infection resistant to these drugs , extended - spectrum cephalosporins ( escs ) are considered as an alternative therapeutic choice . with the increased use of -lactam antibiotics to treat enteric infection , salmonella spp . had acquired resistant to third generation cephalosporin antibiotics in different parts of the world and had been associated with clinical treatment failure [ 3 , 4 ] . extended - spectrum beta - lactamases ( esbl ) are usually encoded by large plasmids ( 100  kb ) that are transferable from strain to strain and between bacterial species [ 57 ] . resistance to escs is mediated primarily by production of class a esbls , which can hydrolyze oxyimino cephalosporins but are not active against cephamycins and carbapenems . the plasmid - encoded ctx - m type esbls production was initially identified in 1983 in germany . the ctx - m family enzymes , which confer high levels of resistance to escs , have similar substrate specificities and inhibitor profiles to tem . the ctx - m type esbls have been reported to be found worldwide in different members of enterobacteriaceae isolated from human and other animal sources . earlier we have reported the emergence of blactx - m and blatem type esbl producer s. typhi in one - year - old child with recurrent high - grade fever . in recent years there have been several reports indicating the emergence of resistance to -lactam antibiotics among salmonella species . here , we present blatem gene mediated esbl production among salmonella spp . isolated from stool specimen of patients with diarrhea in an urban setting of bangladesh . as part of a microbiological analysis of stool sample received at dhaka treatment centre of international centre for diarrheal diseases research , bangladesh ( icddr , b ) during 20052013 , we have analyzed 128,312 fecal specimen following standard microbiological method to identify salmonella spp . the putative extended - spectrum beta - lactamase ( esbl ) producing strains were tested by the double - disc synergy method and detection of -lactamase genes ( blactx - m , blatem , blashv , and blaoxa genes ) was performed by pcr as describe elsewhere . overall , the annual incidence of salmonella infection showed a decreasing trend and the proportion came down significantly from 2% in 2005 to 1.0% in 2013 ( p < 0.001 ) . ( 2120 , [ 1.7% ] ) , nontyphoidal salmonella ( nts ) isolates were more frequently isolated than typhoidal salmonella ( ts ) ( 72.8% versus 27.2% , p < 0.001 ) . demographic information showed that salmonellae were isolated from patients of all age groups with a maiden age of 4.04 years . of the total salmonella positive patients , 51.2% ( n = 1086 ) were children aged less than five years . among the ts serogroups , s. typhi was predominant ( 404 , [ 65.1% ] ) followed by s. paratyphi b ( 139 , [ 22.4% ] ) and s. paratyphi a ( 78 , [ 12.6% ] ) . of the nts isolates , serogroups c1 strains were more frequently isolated ( 560 , [ 37.4% ] ) , followed by b ( 203 , [ 13.5% ] ) , c2 ( 203 , [ 13.5% ] ) , e ( 127 , [ 8.5% ] ) , d ( 94 , [ 6.3% ] ) , g ( 79 , [ 5.3% ] ) , nontypeable salmonella ( 54 , [ 3.6% ] ) , s. typhimurium ( 2 , [ 0.1% ] ) , and a ( 1 , [ 0.06% ] ) serogroup . the yearly distribution of salmonella spp . showed distinct seasonality with higher isolation during may to october in each year . temporal shift was noted in the prevalence of serogroups , seasonality , gender distribution , and resistance pattern between ts and nts isolates . around 40% of the salmonella isolates showed resistance to nalidixic acid ( na ) followed by 36% to ampicillin ( amp ) , 20% to cotrimoxazole ( sxt ) , 4% to ciprofloxacin ( cip ) , 13% to chloramphenicol ( c ) , and 4% to ceftriaxone ( cro ) . resistance to 3 antibiotic classes was more common among ts strains than nts counterpart ( 36.6% versus 19.8% , p < 0.001 ) . among the representative salmonella isolates with unusual resistant phenotype ( ampccipcronasxt ) , first identified in 2011 , blatem gene was detected in 88% ( 7/8 ) of the strains ( figure 1 ) . interestingly , one s. typhi was positive for both blatem and blactx - m genes which is a very rare phenomenon . in our earlier report , we noticed that this same phenomenon was observed in one s. typhi isolated from blood of a typhoid patient . these findings suggest that multi - esbl producer strains are circulating in bangladesh . however , to the best of our knowledge , this is the first report of esbl production among salmonella isolated from stool specimen of diarrheal patients in urban dhaka , bangladesh . detailed molecular characterization including sequencing is necessary for further geno- and subtyping of these strains . the study finding reflects the higher prevalence of mar salmonella spp . among children aged < 5 years and blatem gene mediated esbl production among salmonella spp . isolated from stool sample of diarrheal patient in urban bangladesh . therefore , it is important to establish a surveillance program to understand actual disease burden due to salmonella as well as promote specific and actual line of therapy for salmonellosis .