Traveller's diarrhoea (TD) is the most common illness reported in international travellers. TD is caused by a wide range of pathogens, including bacteria, viruses and parasites. Multiplex PCR assays can be especially useful for studying the aetiology of TD. The first objective of this study was to evaluate the utility of the commercially available multiplex PCR (xTAG(®) Gastrointestinal Pathogen Panel (GPP)) for the diagnosis of TD. A total of 185 stool specimens obtained from 174 patients were processed using the GPP assay. This test detected 86 pathogens in 67 stool samples (67/185, 36.2%). Sixteen pathogens out of 86 were also detected by routine testing. The remaining pathogens (n = 70) required further confirmation by alternative techniques. Finally, 60 out of 70 pathogens were confirmed. The second objective of this study was to analyse the aetiology of TD based on the results obtained by the GPP test and routine methods. The primary pathogens causing TD were Shigella (24.2%) followed by enterotoxigenic Escherichia coli (ETEC) (23.2%), enteroaggregative E. coli (14.7%) and Giardia (13.7%). Significant regional differences were observed for ETEC with 19.4% of TD cases acquired in Africa, 11.3% in Asia and none in South Central (SC) America (p 0.01), Giardia was found in 1.5% of cases among those who had travelled to Africa, 14.1% of those who had travelled to Asia and 3% of those who had travelled to SC America (p 0.01). In conclusion, the GPP test improved the detection of enteropathogens and allowed better assessment of the aetiology of TD.

A carbapenem-resistant Escherichia coli strain (DVR22) was recovered from a stool specimen from a patient with traveler's diarrhea who had traveled to India. Molecular screening led to the first identification of NDM-1 in Spain. The bla NDM-1 gene was located in a conjugative plasmid of ca. 300 kb that also contained the bla CTX-M-15 , bla TEM-1 , ⌬bla DHA-1 , and armA genes. In addition, bla NDM-1 was preceded by an ISAba125 insertion element only found in Acinetobacter spp.The emergence of carbapenem resistance among Enterobacteriaceae is a major cause of concern since carbapenems currently represent the treatment of choice for severe infections caused by multidrug-resistant strains producing extended-spectrum ␤-lactamases (ESBLs) (8).In addition to commonly known carbapenem-hydrolyzing enzymes in Enterobacteriaceae (IMP, VIM, KPC, and OXA-48), a novel class B metallo-␤-lactamase (NDM-1) has recently been described. This enzyme, first identified in Klebsiella pneumoniae and Escherichia coli clinical isolates recovered in Sweden from a traveler returning from India, confers resistance to all ␤-lactams except aztreonam (22). Since then, several reports have identified bla NDM genes worldwide that have typically been associated with multidrug-resistant strains (1,5,12,(16)(17)(18)23).A 40-year-old Spanish Caucasian male reported intermittent abdominal discomfort, fever, and bloody diarrhea about 5 days before returning from India. He visited a local dispensary in India where treatment with ofloxacin and ornidazole tablets (twice a day) was prescribed for 5 days. The patient reported to the Hospital Clinic of Barcelona 1 day after his return, still complaining of bloody diarrhea, although with fewer unformed stools. He was afebrile, without any sign of dehydration, and the rest of the physical examination was normal. The diarrhea resolved spontaneously over the next 9 days.A carbapenem-resistant E. coli (DVR22) strain was recovered from the stool samples of the patient, and after isolation and identification, antimicrobial susceptibility profiling analysis performed with both BD Phoenix (Becton Dickinson, Franklin Lakes, NJ) and Etest strips (AB bioMérieux, Solna, Sweden) indicated that strain DVR22 was resistant to all the antibiotics tested except tigecycline (MIC of 0.75 g/ml), fosfomycin (MIC of 32 g/ml), and colistin (MIC of 0.5 g/ml) (Table 1), presenting MICs of 8 g/ml and 16 g/ml for imipenem and meropenem, respectively, 24 g/ml for ertapenem, and 6 g/ml for doripenem (CLSI breakpoints from broth microdilution tests were used to classify the MICs obtained by Etest [7]). Screening for carbapenemase/MBL production yielded positive results when using either the cloverleaf test (modified Hodge test) or imipenem-EDTA Etest strips. PCR screening for ␤-lactamase genes followed by DNA sequencing using specific primers (NDM-1 F, 5Ј-CCAATATTATGCACC CGGTCG-3Ј, and NDM-1 R 5Ј-ATGCGGGCCGTATGAGT GATTG-3Ј) (2, 14, 21) identified the presence of bla NDM-1 , bla CTX-M-15 , bla TEM-1 , and a partial sequence of the bla DHA-...

The objective of this study was to assess the antimicrobial resistance of enteroaggregative Escherichia coli (EAEC) and enterotoxigenic E. coli (ETEC) strains causing traveler’s diarrhea (TD) and to investigate the molecular characterization of antimicrobial resistance genes to third-generation cephalosporins, cephamycins, and quinolones. Overall, 39 EAEC and 43 ETEC clinical isolates were studied. The susceptibilities of EAEC and ETEC against ampicillin, amoxicillin-clavulanic acid, cefotaxime, imipenem, chloramphenicol, tetracycline, co-trimoxazole, nalidixic acid, ciprofloxacin, azithromycin, and rifaximin were determined. All genes encoding resistance determinants were detected by PCR or PCR plus DNA sequencing. The epidemiology of selected EAEC and ETEC strains was studied using multilocus sequence typing (MLST). The resistance to quinolones of EAEC and ETEC strains causing TD has significantly increased over the last decades, and high percentages have been found especially in patients traveling to India and sub-Saharan Africa. Sequence type 38 (ST38) and ST131, carrying the blaCTX-M-15 and blaCTX-M-27 genes, respectively, are highly prevalent among extended-spectrum β-lactamase (ESBL)-producing EAEC and ETEC strains. The cephamycinase ACT-20 is described in the present study for the first time in EAEC and ETEC strains causing TD in patients who had traveled to Central America. The percentages of resistance to azithromycin in EAEC and ETEC isolates from patients to Southeast Asia/India and Africa are above 25%. Meanwhile, rifaximin is still active against EAEC and ETEC, with the prevalence of resistant strains not being high. In conclusion, fluoroquinolones should no longer be considered the drugs of choice for the prevention or treatment in TD for travelers traveling to India and Africa. Azithromycin and rifaximin are still a good alternative to treat TD caused by EAEC or ETEC.

Travelers’ diarrhea is a major public health problem. From patients in whom diarrhea developed after travel to India, 5 enteroaggregative Escherichia coli strains carrying β-lactamase CTX-M-15 were identified; 3 belonged to clonal complex sequence type 38. This β-lactamase contributes to the multidrug resistance of enteroaggregative E. coli, thereby limiting therapeutic alternatives.