Rapid Detection of Carbapenemase and Extended-Spectrum ß-Lactamase Producing Gram-Negative Bacteria Directly from Positive Blood Cultures Using a Novel Protocol.

BACKGROUND: Early and adequate antibiotic treatment is the cornerstone of improving clinical outcomes in patients with bloodstream infections (BSI). Delays in appropriate antimicrobial therapy have catastrophic consequences for patients with BSI. Microbiological characterization of multi-drug resistant pathogens (MDRP) allows clinicians to provide appropriate treatments. Current microbiologic techniques may take up to 96 h to identify causative pathogens and their resistant patterns. Therefore, there is an important need to develop rapid diagnostic strategies for MDRP. We tested a modified protocol to detect carbapenemase and extended-spectrum ß-lactamase (ESBL) producing Gram-negative bacteria (GNB) from positive blood cultures. METHODS: This is a prospective cohort study of consecutive patients with bacteremia. We developed a modified protocol using the HB&L® system to detect MDRP. The operational characteristics were analyzed for each test (HB&L-ESBL/AmpC® and HB&L-Carbapenemase® kits). The kappa coefficient, sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), likelihood ratios (LR) with 95% confidence intervals (CI), and reduction in identification time of this novel method were calculated. RESULTS: Ninety-six patients with BSI were included in the study. A total of 161 positive blood cultures were analyzed. Escherichia coli (50%, 81/161) was the most frequently identified pathogen, followed by Klebsiella pneumoniae (15%, 24/161) and Pseudomonas aeruginosa (8%, 13/161). Thirty-three percent of isolations had usual resistance patterns. However, 34/161 (21%) of identified pathogens were producers of carbapenemases and 21/161 (13%) of extended-spectrum ß-lactamases. Concordance between our HB&L® modified protocol and the traditional method was 99% (159/161). Finally, identification times were significantly shorter using our HB&L®-modified protocol than traditional methods: median (IQR) 19 h (18, 22) vs. 61 h (60, 64), p < 0.001. CONCLUSIONS: Here, we provide novel evidence that using our HB&L®-modified protocol is an effective strategy to reduce the time to detect MDRP producers of carbapenemases or extended-spectrum ß-lactamases, with an excellent concordance rate when compared to the gold standard. Further studies are needed to confirm these findings and to determine whether this method may improve clinical outcomes.

Sickle cell disease children's gut colonization by extended-spectrum ß-lactamase (ESBL)-producing Enterobacterales: an antibiotic prophylaxis effect?

Introduction. Sickle cell disease (SCD) children have a high susceptibility to pneumococcal infection. For this reason, they are routinely immunized with pneumococcal vaccines and use antibiotic prophylaxis (AP).Hypothesis/Gap Statement. Yet, little is known about SCD children's gut microbiota. If antibiotic-resistant Enterobacterales may colonize people on AP, we hypothesized that SCD children on AP are colonized by resistant enterobacteria species.Objective. To evaluate the effect of continuous AP on Enterobacterales gut colonization from children with SCD.Methodology. We analysed 30 faecal swabs from SCD children on AP and 21 swabs from children without the same condition. Enterobacterales was isolated on MacConkey agar plates and identified by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) (bioMérieux, Marcy l'Etoile, France). We performed the antibiogram by Vitek 2 system (bioMérieux, Marcy l'Etoile, France), and the resistance genes were identified by multiplex PCR.Results. We found four different species with resistance to one or more different antibiotic types in the AP-SCD children's group: Escherichia coli, Klebsiella pneumoniae, Citrobacter freundii, and Citrobacter farmeri. Colonization by resistant E. coli was associated with AP (prevalence ratio 2.69, 95 % confidence interval [CI], 1.98-3.67, P<0.001). Strains producing extended-spectrum ß-lactamases (ESBL) were identified only in SCD children, E. coli, 4/30 (13 %), and K. pneumoniae, 2/30 (7 %). The ESBL-producing Enterobacterales were associated with penicillin G benzathine use (95 % CI, 22.91-86.71, P<0.001). CTX-M-1 was the most prevalent among ESBL-producers (3/6, 50 %), followed by CTX-M-9 (2/6, 33 %), and CTX-M-2 (1/6, 17 %).Conclusion. Resistant enterobacteria colonize SCD children on AP, and this therapy raises the chance of ESBL-producing Enterobacterales colonization. Future studies should focus on prophylactic vaccines as exclusive therapy against pneumococcal infections.

Geographic mapping of Enterobacteriaceae with extended-spectrum ß-lactamase (ESBL) phenotype in Pereira, Colombia.

BACKGROUND: Antimicrobial resistance is an ecological and multicausal problem. Infections caused by extended-spectrum ß-lactamase producing Enterobacteriaceae (ESBL-E) can be acquired and transmitted in the community. Data on community-associated ESBL-E infections/colonizations in Colombia are scarce. Georeferencing tools can be used to study the dynamics of antimicrobial resistance at the community level. METHODS: We conducted a study of geographic mapping using modern tools based on geographic information systems (GIS). Two study centers from the city of Pereira, Colombia were involved. The records of patients who had ESBL-producing Enterobacteriaceae were reviewed. Antimicrobial susceptibility testing and phenotypic detection of ESBL was done according to CLSI standards. RESULTS: A population of 415 patients with community-acquired infections/colonizations and 77 hospital discharges were obtained. Geographic distribution was established and heat maps were created. Several hotspots were evidenced in some geographical areas of the south-west and north-east of the city. Many of the affected areas were near tertiary hospitals, rivers, and poultry industry areas. CONCLUSIONS: There are foci of antimicrobial resistance at the community level. This was demonstrated in the case of antimicrobial resistance caused by ESBL in a city in Colombia. Causality with tertiary hospitals in the city, some rivers and the poultry industry is proposed as an explanation of the evidenced phenomenon. Geographic mapping tools are useful for monitoring antimicrobial resistance in the community.

High prevalence of blaCTX-M-14 among genetically diverse Escherichia coli recovered from retail raw chicken meat portions in Japan.

Global widespread of extended-spectrum ß-lactamase (ESBL)-producing Enterobacteriaceae, especially Escherichia coli poses a greater threat in healthcare and community settings of humans. Raw meats from food animals colonized with ESBL producers may be one of important transmission routes for those bacteria in the community. This study investigated the presence of ESBL-producing E. coli in retail raw chicken and pork meats in Japan. ESBL producers were detected from the 59 of 150 (39.3%) chicken samples, but none were from all the 50 pork samples tested. The blaCTX-M-14 (17; 24.3%) was most frequently identified, followed by blaCTX-M-2 (16; 22.9%), blaSHV-12 (11; 15.7%), and blaCTX-M-55 (10; 14.3%) among a total of 70 ESBL-producing E. coli isolates from 59 chicken samples. The isolates with blaCTX-M-14 were often combined with phylogroup B1 (9/17) mainly composed of ST162 (7/9), and phylogroup F (5/17) with diverse STs. The blaCTX-M-14 was basically associated with the common elements ISEcp1 and ΔIS903 or IS903 in all 17 isolates. In 6 isolates, comprising 5 phylogroup B1-ST162 and a nontypeable-ST162 isolates, an IS26-truncated ISEcp1 was identified upstream of the blaCTX-M-14, and a fosA3 was further located downstream of ΔIS903. Furthermore, some mobile genetic elements mediating blaCTX-M-14 unique to raw chicken meat portions were identified. The blaCTX-M-2 gene was preceded by ISEcp1 or ISCR1 in 16 isolates, whereas the presence of Δorf3 downstream of blaCTX-M-2 was limited only in 6 isolates from Brazilian samples though they exhibited diverse phylogroups and STs. The blaCTX-M-55 and blaCTX-M-1 shared classical flanking structures, ISEcp1-blaCTX-M-orf477, although the length of spacer sequences between ISEcp1 and the start codon of blaCTX-M was 45 bp and 80 bp for blaCTX-M-55 and blaCTX-M-1, respectively. Among blaSHV-12-harboring isolates, ST38 was frequently detected (6/11) though their phylogroup distribution varied. In conclusion, besides transmission of bla gene-harboring E. coli lineages which have adaptability to both human and chicken, spread of mobile genetic elements associated with bla genes from E. coli lineages adapted to chicken to those adapted to human is highly suggested. Our results provide important information to gain a better understanding of the transmission risk of bla genes from retail chicken meats to human.

Estudio preliminar de Infecciones Urinarias Intrahospitalarias en Salas de Clínica Médica de un hospital público de San Lorenzo / Preliminary study of intrahospital urinary tract infections in Internal Medicine rooms from a public Hospital in San Lorenzo

Fundamento y objetivo: Con este estudio preliminar pretendemos determinar las características demográficas y la relación entre determinados factores de riesgo con la presencia de bacterias gram negativas productoras de betalactamasas de espectro extendido (BLEE) en infecciones del tracto urinario de pacientes internados (ITU-IH). Materiales y Métodos: Se realizó un estudio observacional, retrospectivo de corte transversal del tipo casos y controles; de los pacientes adultos de ambos sexos que permanecieron internados en las salas de Clínica Médica del Hospital de Clínicas, de la ciudad de San Lorenzo, de enero del 2015 a agosto del 2017 con urocultivo positivo para bacterias Gram negativas y su relación con diversos factores. Resultados: Escherichia Coli fue aislada en el 43% de las IVU intrahospitalarias, seguida por Klebsiella pneumoniae (32%), Pseudomona aeruginosa (9%), Enterobacter cloacae (4%), Proteus mirabilis (4%), Morganella morganii (2%). En cuanto a los factores de riesgo asociados a ITU-IH debidas a bacterias gram negativas productoras de BLEE, el uso previo de antibiótico (ATB) fue el factor con mayor asociación con OR 2,5 (IC 95% 2,5-21,8) p 0,001. Conclusión: La bacteria Gram negativa implicada con mayor frecuencia en las ITU-IH fue Escherichia coli. El mayor porcentaje de los pacientes que presentó una ITU-IH durante su internación pertenecía al sexo femenino, presentaba algún tipo de comorbilidad; y permaneció hospitalizado por más de 10 días. En cuanto a los factores de riesgo asociados a ITU-IH producidas por bacterias Gram negativas productoras de BLEE, el uso previo de antibiótico fue el factor encontrado con mayor asociación.

Ground and objective: On this preliminary study we aim to determine the demographic features and the relation between certain risk factors and the presence of Gram negative betalactamase producing bacteria (ESBL) in urinary tract infections (UTI) on hospitalized patients. Materials and Methods: An observational, retrospective, cross sectional, case control type study was performed; on adult patients of both genders that were hospitalized in the Internal Medicine wards from Hospital de Clínicas, in the city of San Lorenzo, from January 2015 to August 2017, that had positive urine culture for Gram negative bacteria, and its relationship with diverse factors. Results: Escherichia Coli was isolated on 43% of nosocomial UTI, followed by Klebsiella pneumoniae (32%), Pseudomona aeruginosa (9%), Enterobacter cloacae (4%), Proteus mirabilis (4%), Morganella morganii (2%). As for the risk factors associated to nosocomial UTI produced by Gram negative ESBL-producing bacteria, the prior use of antibiotics was the greatest associated factor with an OR 2,5 (CI 95% 2,5-21,8) p 0,001. Conclusion: The most implicated Gram negative bacteria on nosocomial UTI was Escherichia Coli. The greatest percentage of patients that presented nosocomial UTI during their admission belonged to female sex, presented comorbidities and was hospitalized for a period longer than 10 days. As to the associated risk factors for nosocomial UTI produced by Gram negative ESBL-producing bacteria, the prior use of antibiotics was the greatest associated factor.

Multidrug resistance dissemination by extended-spectrum ß-lactamase-producing Escherichia coli causing community-acquired urinary tract infection in the Central-Western Region, Brazil.

The aim of this work was to analyse extended-spectrum ß-lactamase (ESBL)-producing Escherichia coli strains isolated from outpatients with signs of cystitis in Hospital Universitário de Brasília (Brasília, Brazil) during the period July 2013 to April 2014. E. coli isolated from urine culture were identified and their antibiotic susceptibility profile was determined by VITEK 2. ESBL-producing strains identified were submitted to PCR for Clermont phylotyping, CTX-M group typing and virulence determinant detection, and clonal relationships were determined by enterobacterial repetitive intergenic consensus (ERIC)-PCR. One strain belonging to each cluster of the dendrogram obtained by ERIC-PCR was selected for multilocus sequence typing (MLST). Among 324 uropathogenic E. coli (UPEC) analysed, 23 (7.1%) were identified as producing ESBL. All ESBL-producing strains were multidrug-resistant (MDR), i.e. presented non-susceptibility to at least one agent in three or more antimicrobial categories. Of the 23 ESBL-producing UPEC strains, 9 were assigned to phylogenetic group B2 and 7 each belonged to phylogenetic groups D and A. Virulence genotyping showed that aer was the most prevalent gene observed among the strains (21/23), followed by traT (18/23), pap (5/23), afa (5/23), PAI (5/23), cnf (3/23) and sfa (1/23). Analysis of the dendrogram showed that multidrug resistance and CTX-M ESBL groups were distributed among all strains, independent of clonality and phylogroup. Sequence types (STs) associated with pandemic resistance clones, such as B2-ST131 and D-ST648, were observed among the isolates. In conclusion, the results showed worrisome evidence of the potential for antibiotic multiresistant dissemination among community-acquired urinary tract infection caused by UPEC.