Antibiotic susceptibility and fosfomycin resistance characterization in a cohort of children older than 6 years of age with urinary tract infection.

Fosfomycin tromethamol (FT) was reintroduced as an option for the treatment of low urinary tract infection (UTI) in children. In this study, we described the antibiotic sensitivity and mechanisms of resistance to fosfomycin in isolates from children older than 6 years with UTI. Urine culture and antibiotic susceptibility study were performed. In fosfomycin resistant strains, PCR for fos, blaCTX-M was performed followed by classification by phylogenetic group and sequencetyping. Escherichia coli was the most frequent etiological agent (89.2%). The susceptibility percentages were: fosfomycin 97.9%; amoxicillin-clavulanate 92.7%; cefuroxime and ceftriaxone 99%; nitrofurantoin 94.4%. An E. coli strain (ST69, phylogenetic group D) was resistant to fosfomycin (MIC 256mg/l) and carried the blaCTX-M-14 and fosA3 genes in a 45kb IncN-type plasmid. This is the first report of E. coli ST69 with blaCTX-M-14/fosA3 of human origin.

First three Escherichia coli isolates harbouring mcr-1 in Uruguay.

OBJECTIVE: This report described the first Escherichia coli (E. coli) isolates harbouring mcr-1 in Uruguay. METHODS: Three E. coli isolates were obtained from blood, urine and rectal swabs from different patients in two hospitals. Extended-spectrum ß-lactamases (ESBL), plasmid-encoded (pAmpC) ß-lactamases, plasmid-mediated quinolone resistance (PMQR) genes, class 1 integrons, and mcr-1, mcr-2 and mcr-3 were sought and characterised in three E. coli isolates. Transfer of resistance determinants was assessed by conjugation. Clonality was analysed by multilocus sequence typing. RESULTS: All isolates were categorised as being colistin-resistant and the mcr-1 gene was detected. Two isolates were also resistant to oxyimino cephalosporins: one on account of blaCMY-2 and the other due to blaCTX-M-15, the latter also harbouring transferable quinolone-resistance genes (aac(6')Ib-cr and qnrB). All mcr-1 genes were transferred by conjugation to recipient strains. The mcr-1-bearing isolates belonged to sequence types ST10, ST93 and ST5442. CONCLUSIONS: ST10 is considered as a high-risk clone worldwide. This type of mcr-1-harbouring clone is a major concern for human and animal health and must be under close surveillance. This study detected the presence of mcr-1 for the first time in Uruguay, albeit in an allodemic manner, associated with different antibiotic-resistance genes and from diverse clinical contexts. Considering that colistin is often the last therapeutic option available for multidrug-resistant Gram-negative bacilli infections, it is important to maximise precautions to avoid dissemination of isolates carrying mcr-1.

Polyclonal Campylobacter fetus Infections Among Unrelated Patients, Montevideo, Uruguay, 2013-2018.

In Montevideo (2013-2018), 8 Campylobacter fetus extraintestinal infections were reported. The polyclonal nature of strains revealed by whole-genome sequencing and the apparent lack of epidemiological links was incompatible with a single contamination source, supporting alternative routes of transmission.

First characterization of K. pneumoniae ST11 clinical isolates harboring blaKPC-3 in Latin America.

Antimicrobial resistance due to carbapenemase production in Enterobacteriaceae clinical isolates is a global threat. Klebsiellapneumoniae harboring the blaKPC gene is one of the major concerns in hospital settings in Latin America. The aim of this study was to characterize the antibiotic resistance mechanisms and to typify four carbapenem-resistant K. pneumoniae clinical isolates from the city of Manizales, Colombia. We identified blaKPC-3 in all four isolates by polymerase chain reaction and subsequent sequencing. The plasmid-mediated quinolone resistance genes qnrB19-like and aac(6')Ib-cr; fosfomycin resistance gene fosA and an insertion sequence IS5-like in mgrB (colistin resistance) were also detected. Sequence types ST11 with capsular type wzi75, and ST258 with wzi154, were characterized. The blaKPC-3 gene was mobilized in a 100-kb IncFIB conjugative plasmid with vagCD toxin-antitoxin system. This work reports multiple resistance genes in blaKPC-producing K. pneumoniae and the first occurrence of ST11 clinical isolates harboring blaKPC-3 in Latin America.

Detection of qnrVC6, within a new genetic context, in an NDM-1-producing Citrobacter freundii clinical isolate from Uruguay.

OBJECTIVES: The objective of this study was to characterise the mechanisms underlying quinolone and oxyimino-cephalosporin resistance in a Citrobacter freundii clinical isolate obtained from the ICU in a university hospital in Uruguay. METHODS: Citrobacter freundii strain CF638 was isolated from a urine culture. Identification was performed using a VITEK®2 system, and antimicrobial susceptibility was established by MIC determination and disk diffusion assay. Resistance genes and mobile genetic elements were identified by PCR and sequencing. Plasmid transfer was assessed by conjugation and the plasmid size was estimated by S1-PFGE. Plasmid incompatibility (Inc) group and toxin-antitoxin systems were sought by PCR. RESULTS: Strain CF638 showed a multidrug-resistant profile, including resistance to carbapenems and quinolones. Transconjugant TcCF638, harbouring an ca. 200-kb IncA/C plasmid, also showed resistance to all ß-lactams (except aztreonam) and diminished susceptibility to ciprofloxacin. PCR was positive for blaNDM-1 and qnrVC in CF638 and TcCF638. Two different class 1 integrons were detected (In127 and In907). In127 featured the genetic array aadA2-ltr2. Conversely, complex In907 featured two variable regions (VRs); VR-1 consisted of aadB-blaOXA-10-aadA1cc, whereas VR-2 featured a qnrVC6 gene 108bp downstream from ISCR1 and 45bp upstream from qacEΔ1. Expression of qnrVC6 was due to a putative promoter region, detected using the Neural Network Promoter Prediction program. CONCLUSION: To the best of our knowledge, this constitutes the first report of qnrVC within a complex class 1 integron, as well as the first report of the occurrence of such a gene in an NDM-1-producing enterobacterial clinical isolate.

[Bacteraemia due to Shigella flexneri serotype 6 in two patients with AIDS]. / Bacteriemia por Shigellaflexneri serotipo 6 en pacientes con SIDA: Presentación de dos casos clínicos.

Infections due to Shigella usually remain localized to the digestive tract and are self-limited. Bacteremia is a potentially lethal complication that can occur in immunocompromised patients. We describe two episodes of bacteremia caused by Shigella in two adults with AIDS. In both patients, S. flexneri was recovered from stool and blood samples. The isolates belonged to serotype 6, were resistant only to trimethoprim-sulfamethoxazole and showed a similar band profile by pulsed-field gel electrophoresis. Patients received prolonged antimicrobial treatment with a favorable outcome. There were no cases of diarrhea in other individuals admitted to the emergency room. We hypothesized that patient No. 2 was infected at the hospital from patient No. 1. However, we could not establish the way of transmission. Although rare, it is important to take into account the possible occurrence of bacteremia due to Shigella or other bacterial enteropathogens in immunocompromised patients with diarrhea.

Bacteriemia por Shigellaflexneri serotipo 6 en pacientes con SIDA: Presentación de dos casos clínicos / Bacteraemia due to Shigella flexneri serotype 6 in two patients with AIDS

Infections due to Shigella usually remain localized to the digestive tract and are self-limited. Bacteremia is a potentially lethal complication that can occur in immunocompromised patients. We describe two episodes of bacteremia caused by Shigella in two adults with AIDS. In both patients, S. flexneri was recovered from stool and blood samples. The isolates belonged to serotype 6, were resistant only to trimethoprim-sulfamethoxazole and showed a similar band profile by pulsed-field gel electrophoresis. Patients received prolonged antimicrobial treatment with a favorable outcome. There were no cases of diarrhea in other individuals admitted to the emergency room. We hypothesized that patient No. 2 was infected at the hospital from patient No. 1. However, we could not establish the way of transmission. Although rare, it is important to take into account the possible occurrence of bacteremia due to Shigella or other bacterial enteropathogens in immunocompromised patients with diarrhea.

Las infecciones por Shigella spp., en general, permanecen localizadas en el tracto digestivo y tienen una evolución autolimitada. La bacteriemia es una complicación potencialmente letal que ocurre en pacientes con algún tipo de inmunocompromiso. Presentamos dos casos de bacteriemia causadas por Shigella en dos adultos con SIDA. En ambos pacientes, se recuperó Shigella flex-neri en muestras de deposiciones y sangre. Los aislados correspondieron al serotipo 6, fueron resistentes sólo a cotrimoxazol y mostraron un perfil de bandas similar por PFGE. Los pacientes recibieron tratamiento antimicrobiano prolongado y la evolución fue favorable. No se registraron otros casos de diarrea en individuos admitidos en el servicio de emergencia. La hipótesis fue que el paciente 2 adquirió la infección en el hospital a partir del paciente 1. Sin embargo, no pudimos establecer el modo de transmisión. Aunque poco frecuente, es importante tener presente la ocurrencia de bacteriemia por Shigella spp. o por otros enteropatógenos bacterianos en pacientes inmunocomprometidos con diarrea.

First human isolate of Salmonella enterica serotype Enteritidis harboring blaCTX-M-14 in South America.

We studied a clinical isolate of Salmonella enterica serotype Enteritidis showing resistance to oxyiminocephalosporins. PCR analysis confirmed the presence of bla(CTX-M-14) linked to IS903 in a 95-kb IncI1 conjugative plasmid. Such a plasmid is maintained on account of the presence of a pndAC addiction system. Multilocus sequence typing (MLST) analysis indicated that the strain belongs to ST11. This is the first report of bla(CTX-M-14) in Salmonella Enteritidis of human origin in South America.