Effectiveness of a Double-Carbapenem Regimen in a KPC-Producing Klebsiella pneumoniae Infection in an Immunocompromised Patient.

The progressive increase of infections produced by extensively drug-resistant carbapenemase-producing Klebsiella pneumoniae (XDR-CPKP) represents an important threat to public health. Unfortunately, optimal therapeutic options are scarce. Retrospective studies have recommended combined therapy with more than one antibiotic and, more recently, a double-carbapenem regimen has been reported to be an effective alternative therapy. Here, we describe an episode of sepsis in an immunocompromised patient after allogeneic hematopoietic stem cell transplantation, caused by an XDR-CPKP. Several in vitro synergy tests revealed a synergistic effect combining ertapenem and meropenem, which were used as combination therapy achieving clinical and microbiological success.

Carbapenemase-producing enterobacteriaceae recovered from a Spanish river ecosystem.

The increasing resistance to carbapenems is an alarming threat in the fight against multiresistant bacteria. The dissemination properties of antimicrobial resistance genes are supported by their detection in a diverse population of bacteria, including strains isolated from the environment. The objective of this study was to investigate the presence of carbapenemase-producing Enterobacteriaceae (CPE) collected from a river ecosystem in the Barcelona metropolitan area (Spain). Identification of ß-lactamases and other resistance determinants was determined as was the antimicrobial susceptibility profile. Moreover, screening of virulence factors, plasmid addiction systems, plasmid partition systems and replicon typing was performed. The results identified 8 isolates belonging to different species (Escherichia coli, Enterobacter cloacae, Klebsiella pneumoniae, Klebsiella oxytoca, Raoultella ornithinolytica). The most prevalent enzyme was KPC-2 (n = 6), followed by VIM-1 (n = 2) and IMI-2 (n = 1), whereas no OXA-48-type was detected. In addition, one strain was positive for both KPC-2 and VIM-1 enzymes. All the carbapenemase-encoding plasmids carried at least one plasmid addiction or partition system, being vagCD and parAB the most frequently detected, respectively. E. coli and K. pneumoniae isolates carried a low number of virulence-associated factors and none of the detected clones has previously been identified in the clinical setting. These findings support the high dissemination potential of the carbapanemase-encoding genes and reinforce the idea that the environment is another reservoir that may play an important role in the capture, selection and dissemination of carbapenem resistance genes.

Diversity of Multi-Drug Resistant Avian Pathogenic Escherichia coli (APEC) Causing Outbreaks of Colibacillosis in Broilers during 2012 in Spain.

Avian pathogenic Escherichia coli (APEC) are the major cause of colibacillosis in poultry production. In this study, a total of 22 E. coli isolated from colibacillosis field cases and 10 avian faecal E. coli (AFEC) were analysed. All strains were characterised phenotypically by susceptibility testing and molecular typing methods such as pulsed-field gel electrophoresis (PFGE) and multi-locus sequence typing (MLST). The presence of 29 virulence genes associated to APEC and human extraintestinal pathogenic E. coli (ExPEC) was also evaluated. For cephalosporin resistant isolates, cephalosporin resistance genes, plasmid location and replicon typing was assessed. Avian isolates belonged to 26 O:H serotypes and 24 sequence types. Out of 22 APEC isolates, 91% contained the virulence genes predictors of APEC; iutA, hlyF, iss, iroN and ompT. Of all strains, 34% were considered ExPEC. PFGE analysis demonstrated a high degree of genetic polymorphism. All strains were multi-resistant, including those isolated from healthy animals. Eleven strains were resistant to cephalosporins; six contained blaCTX-M-14, two blaSHV-12, two blaCMY-2 and one blaSHV-2. Two strains harboured qnrA, and two qnrA together with aac(6')-Ib-cr. Additionally, the emergent clone O25b:H4-B2-ST131 was isolated from a healthy animal which harboured blaCMY-2 and qnrS genes. Cephalosporin resistant genes were mainly associated to the presence of IncK replicons. This study demonstrates a very diverse population of multi-drug resistant E. coli containing a high number of virulent genes. The E. coli population among broilers is a reservoir of resistance and virulence-associated genes that could be transmitted into the community through the food chain. More epidemiological studies are necessary to identify clonal groups and resistance mechanisms with potential relevance to public health.

Houseflies (Musca domestica) as Vectors for Extended-Spectrum ß-Lactamase-Producing Escherichia coli on Spanish Broiler Farms.

Flies may act as potential vectors for the spread of resistant bacteria to different environments. This study was intended to evaluate the presence of Escherichia coli strains resistant to cephalosporins in flies captured in the areas surrounding five broiler farms. Phenotypic and molecular characterization of the resistant population was performed by different methods: MIC determination, pulsed-field gel electrophoresis (PFGE), multilocus sequence typing (MLST), and phylotyping. The presence of extended-spectrum beta-lactamase (ESBL) genes, their plasmid location, and the mobile genetic elements involved in their mobilization were studied. Additionally, the presence of 35 genes associated with virulence was evaluated. Out of 682 flies captured, 42 yielded ESBL-producing E. coli. Of these isolates, 23 contained bla(CTX-M-1), 18 contained bla(CTX-M-14), and 1 contained bla(CTX-M-9). ESBL genes were associated mainly with the presence of the IncI1 and IncFIB replicons. Additionally, all the strains were multiresistant, and five of them also harbored qnrS. Identical PFGE profiles were found for E. coli isolates obtained from flies at different sampling times, indicating a persistence of the same clones in the farm environment over months. According to their virulence genes, 81% of the isolates were considered avian-pathogenic E. coli (APEC) and 29% were considered extraintestinal pathogenic E. coli (ExPEC). The entrance of flies into broiler houses constitutes a considerable risk for colonization of broilers with multidrug-resistant E. coli. ESBLs in flies reflect the contamination status of the farm environment. Additionally, this study demonstrates the potential contribution of flies to the dissemination of virulence and resistance genes into different ecological niches.

ESBL-producing Salmonella enterica serovar Typhi in traveler returning from Guatemala to Spain.

We report a case of typhoid fever in a traveler returning to Spain from Guatemala that was caused by Salmonella enterica serovar Typhi which produced an extended-spectrum ß-lactamase (ESBL). This finding demonstrates the presence of ESBL-producing S. enterica ser. Typhi strains in the Americas. Enhanced surveillance is necessary to prevent further spread.