RESUMO
The aim of this study was to compare the performance of two MALDI-TOF MS systems in the identification of clinically relevant strict anaerobic bacteria. The 16S rRNA gene sequencing was the gold standard method when discrepancies or inconsistencies were observed between platforms. A total of 333 isolates were recovered from clinical samples of different centers in Buenos Aires City between 2016 and 2021. The isolates were identified in duplicate using two MALDI-TOF MS systems, BD Bruker Biotyper (Bruker Daltonics, Bremen, Germany) and Vitek MS (bioMèrieux, Marcy-l'Etoile, France). Using the Vitek MS system, the identification of anaerobic isolates yielded the following percentages: 65.5% (n: 218) at the species or species-complex level, 71.2% (n: 237) at the genus level, 29.4% (n: 98) with no identification and 5.1% (n: 17) with misidentification. Using the Bruker Biotyper system, the identification rates were as follows: 85.3% (n: 284) at the species or species-complex level, 89.7% (n: 299) at the genus level, 14.1% (n: 47) with no identification and 0.6% (n: 2) with misidentification. Differences in the performance of both methods were statistically significant (p-values <0.0001). In conclusion, MALDI-TOF MS systems speed up microbial identification and are particularly effective for slow-growing microorganisms, such as anaerobic bacteria, which are difficult to identify by traditional methods. In this study, the Bruker system showed greater accuracy than the Vitek system. In order to be truly effective, it is essential to update the databases of both systems by increasing the number of each main spectrum profile within the platforms.
Assuntos
Bactérias Anaeróbias , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz/métodos , Bactérias Anaeróbias/genética , RNA Ribossômico 16S/genética , ArgentinaRESUMO
Diabetic foot ulcers (DFU) are exacerbated by bacterial colonisation. Here, a high prevalence of Enterococcus faecalis was observed in DFU patients from an Argentinean hospital. E. faecalis was frequently co-isolated with Escherichia coli, Morganella morganii, and Pseudomonas aeruginosa. The effect of interspecies interactions on bacterial growth was investigated in mixed-species macrocolony biofilms developed in Lubbock-Glc-agar. Similar cell counts were found for E. faecalis and M. morganii growing in mixed and single-species biofilms. An E. faecalis strain showed 1 Log higher cell counts in mixed biofilms with E. coli. Remarkably, E. faecalis strains showed 2 to 4 Log higher cell counts in mixed biofilms with P. aeruginosa. This effect was not observed in planktonic growth or biofilms developed in tryptic soy agar. The present findings reveal bacterial interactions that benefit E. faecalis in mixed-species biofilms, mainly with P. aeruginosa, in a medium that partially mimics the nutrients found in DFU.
Assuntos
Diabetes Mellitus , Pé Diabético , Humanos , Biofilmes , Escherichia coli , Enterococcus faecalis , Ágar/farmacologiaRESUMO
A brain abscess is a focal infection characterized by a collection of pus in the brain parenchyma. It is a life-threatening condition that should be diagnosed and treated as soon as possible. We report here three cases of patients with otogenic brain abscesses of polymicrobial origin that had in common the isolation of Actinomyces europaeus, which has not been previously described in this location. A. europaeus was identified by the conventional methodology, matrix-associated laser deionization-time of flight mass spectrometry (MALDI-TOF MS) and 16S rRNA gene sequencing. Antibiotic susceptibility was evaluated by the epsilometric method, and all isolates showed sensitivity to penicillin, vancomycin and linezolid, whereas susceptibility to clindamycin and erythromycin was variable. MALDI-TOF MS identification allowed a quick and reliable species level identification in order to provide a rapid and effective response to avoid treatment delay that could lead to increased morbidity and even mortality.
Assuntos
Actinomyces , Abscesso Encefálico , Humanos , RNA Ribossômico 16S/genética , Actinomyces/genética , Abscesso Encefálico/complicações , Clindamicina , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz/métodosRESUMO
Two commercial MALDI-TOF MS systems were used to identify 18 isolates, belonging to the Peptoniphilus genus; also the 16S rRNA sequencing identity was compared against the MALDI-TOF MS system results. Bruker Biotyper system provided higher accuracy than Vitek MS system, however, adding spectra could allow a more reliable species level identification.
Assuntos
Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz , Técnicas de Tipagem Bacteriana/métodos , RNA Ribossômico 16S/genética , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz/métodosRESUMO
Empyema necessitatis (EN) is a very rare complication of a pleural empyema, in which the infection extends to adjacent soft tissues. Anaerobic bacteria are very rare etiologic agents of EN, which occurs in the course of chronic infections. We present the first case of empyema necessitatis caused by Campylobacter rectus. Bacterial identification was carried out by mass spectrometry (MALDI-TOF MS) and antimicrobial susceptibility was determined by the epsilometer method.
Assuntos
Empiema Pleural , Humanos , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz , Empiema Pleural/microbiologiaRESUMO
Dolosigranulum pigrum is a gram-positive, facultatively anaerobic coccus, which is part of the oral and upper respiratory tract microbiota. Although reports of infections by this microorganism are scarce, it has been associated with a wide spectrum of infectious diseases. The case of an elderly man with a lower corneal abscess, in which Dolosigranulum pigrum was isolated, is described. The microorganism was identified by mass spectrometry (MALDI-TOF MS) and by the sequencing of the 16S rRNA gene. Furthermore, the presumptive identification of the causative agent was achieved by using key phenotypic tests such as the cluster arrangement in Gram stain, the negative catalase test, the production of pyrrolidonyl arylamidase and leucine aminopeptidase activity, the growth in 6.5% NaCl and esculin hydrolysis. The data from the literature (and the present case) support the association of the microorganism with ocular infections, which often take a destructive course, mainly in elderly patients.
Assuntos
Infecções por Bactérias Gram-Positivas , Cocos Gram-Positivos , Abscesso , Idoso , Carnobacteriaceae , Cocos Gram-Positivos/genética , Humanos , Masculino , RNA Ribossômico 16S/genéticaRESUMO
Actinomyces and related genera are grampositive bacilli, opportunistic pathogens, which have been mainly involved in endogenous infections. However, due to the complexity in identifying them for most clinical laboratories, there is scant knowledge about their real clinical significance. In this work, 166 isolates of 13 different species of Actinomyces/Actinotignum species recovered from clinical samples of patients treated in a university hospital were studied. The identification was performed by MALDI-TOF MS and molecular identification. MALDI-TOF MS identified 91.57% of the isolates (152/166) at the species level using a score ≥ 1.7 and 3.61% (6/166) of the isolates were identified only at the gender level with a score ≥ 1.5. MALDI-TOF MS did not yield reliable identification results for 4.82% (8/166) of the isolates. Actinomyces/Actinotignum species were isolated from: soft tissue (n: 47), urine samples (n: 35), head / neck abscesses (n: 19), genital abscesses (n: 11), blood samples (n: 10), breast abscesses (n: 8), osteoarticular samples (n: 6), abdominal/ascitic fluids (n: 3), abdominal abscesses (n: 5), sputum/BAL (n: 4), brain abscesses (n: 3), and others (n: 15). The results obtained from the statistical analysis showed a high differential frequency (> 2) for the location/species association: urine/A. schaalii/sanguinis; brain abscesses/A. europaeus; osteoarticular samples/A. urogenitalis; abdominal abscesses/ A. turicensis; respiratory samples/A. naeslundii/viscosus. This information provides a greater understanding of the clinical and epidemiological relevance of these species. The pathogenic role of Actinomyces spp. will be increasingly revealed as these microorganisms could be recognized thanks to prolonged culture and the advances in identification technology facilitated by MALDI-TOF MS.
Assuntos
Actinomyces , Actinomycetaceae , Hospitais , Humanos , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por MatrizRESUMO
Corynebacterium kroppenstedtii is an immobile, non-sporulated, glucose-fermenting and lipophilic gram-positive rod of the skin microbiota. In recent years, numerous isolates of this species have been reported mainly in breast infections, such as abscesses and granulomatous mastitis. We present here four cases of C. kroppenstedtii infections isolated from breast aspiration samples in women. C. kroppenstedtii was identified by conventional methodology and mass spectrometry (MALDI-TOF MS). Using the epsilometric method, these isolates showed susceptibility to penicillin, ceftriaxone, minocycline, ciprofloxacin, and vancomycin, and variable susceptibility to clindamycin and trimethoprim sulfamethoxazole. Due to the association of C. kroppenstedtii with mammary infections, the identification at the species level of those corynebacteria isolated from this location is highly advisable in order to reach the final diagnosis and to test the antimicrobial susceptibility in order to apply the appropriate antibiotic treatment.
Assuntos
Infecções por Corynebacterium , Mastite Granulomatosa , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Mama , Corynebacterium , Infecções por Corynebacterium/diagnóstico , Infecções por Corynebacterium/tratamento farmacológico , Feminino , Mastite Granulomatosa/tratamento farmacológico , HumanosRESUMO
Intramammary infections (IMI) cause serious economic losses for farmers and the dairy industry. Cases of subclinical mastitis are commonly the result of infection by minor pathogens such as non-aureus staphylococci (NAS), so their correct identification is important for appropriate therapeutic intervention and management. The aim of this study was to assess the reliability of PCR-Restriction Fragment Length Polymorphism (PCR-RFLP) of the groEL and gap genes to discriminate between bovine-associated NAS species, using matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) as the reference method. MALDI-TOF MS was able to correctly identify 112 NAS isolates from bovine IMI at species level out of a total of 115 (97.4%). These results were considered definitive and thus compared with those from the PCR-RFLP analyses. Only 50% (56/112) of the samples classified through groEL PCR-RFLP matched the molecular identity determined by MALDI-TOF MS, whereas coincidence rose to 96.4% (108/112) when comparing results from gap PCR-RFLP and the spectral analysis. This study demonstrates that gap PCR-RFLP is a useful and reliable tool for the identification of NAS species isolated from bovine mastitis.
Assuntos
Mastite Bovina , Infecções Estafilocócicas , Animais , Bovinos , Feminino , Reação em Cadeia da Polimerase , Polimorfismo de Fragmento de Restrição , Reprodutibilidade dos Testes , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz , Infecções Estafilocócicas/veterinária , Staphylococcus/genéticaRESUMO
Diabetic foot ulcer infections are frequently polymicrobial in nature and exhibit increased morbidity and mortality, as well as, treatment failures. Interactions between Acinetobacter baumannii and Staphylococcus aureus were studied, which showed strain-dependent changes in growth and antibiotic susceptibility. This study examined the interactions between two clinical strains of A. baumannii (1929) and S. aureus (1928) that were recovered from skin and soft tissues of a diabetic patient. When S. aureus 1928 and A. baumannii 1929 were co-cultured together, there was no significant decrease in growth in either clinical strains, indicating that both strains can co-exist in the same site of infection. Additionally, neither strains experienced statistically significant changes in susceptibility. These findings highlight that these two pathogens can be found in the same niche of infection, which may lead to more aggressive outcome of the infection.
Assuntos
Infecções por Acinetobacter/microbiologia , Coinfecção/microbiologia , Pé Diabético/microbiologia , Interações Microbianas , Infecções dos Tecidos Moles/microbiologia , Infecções Estafilocócicas/microbiologia , Acinetobacter baumannii/efeitos dos fármacos , Acinetobacter baumannii/crescimento & desenvolvimento , Acinetobacter baumannii/isolamento & purificação , Acinetobacter baumannii/fisiologia , Antibacterianos/farmacologia , Complicações do Diabetes/microbiologia , Humanos , Testes de Sensibilidade Microbiana , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/crescimento & desenvolvimento , Staphylococcus aureus/isolamento & purificação , Staphylococcus aureus/fisiologiaRESUMO
Members of the viridans group streptococci (VGS) are the cause of local and invasive infections. Due to the severity of these infections and taking into account that reports regarding epidemiological aspects are scarce, the aims of this work were the identification and the study of the antibiotic susceptibility profiles of the isolates recovered from patients that were hospitalized in order to find out about the resistance level and the epidemiology of infections in which VGS are involved. A hundred and thirty two isolates identified as VGS were isolated at Hospital de Clínicas «José de San Martín¼ during the period 2011-2015. The identification was performed by biochemical test and mass spectrometry by Matrix Assisted Laser Desorption Ionization -Time of Flight Mass Spectrometry. Streptococcus anginosus group was prevalent (42%) followed by Streptococcus mitis group (33%). In the latter, isolates of Streptococcus pneumoniae were excluded. All the VGS isolates were susceptible to ertapenem, meropenem, linezolid and vancomycin; 25.8% were resistant (I+R) to penicillin, being prevalent in the S. mitis group. Regarding ceftriaxone and cefepime 96.9% of the isolates were susceptible. Only two isolates were resistant to levofloxacin, 27.2% to tetracycline and it was not found high level resistance to gentamycin (MIC range 0.5-32µg/ml). Resistance to erythromycin was 17.4% with no significant difference between M and MLS phenotypes. The most active antibiotics were in addition to ceftriaxone and cefepime, vancomycin, ertapenem, meropenem and linezolid. These results highlight the importance of the continuous surveillance of the infections caused by VGS in order to predict a correct antibiotic therapy.
Assuntos
Antibacterianos/farmacologia , Estreptococos Viridans/efeitos dos fármacos , Argentina , Farmacorresistência Bacteriana , Hospitalização , Hospitais de Ensino , Humanos , Testes de Sensibilidade Microbiana , Infecções Estreptocócicas/tratamento farmacológico , Infecções Estreptocócicas/microbiologia , Saúde da População Urbana , Estreptococos Viridans/isolamento & purificaçãoRESUMO
The best laboratory diagnostic approach to detect Clostridioides [Clostridium] difficile infection (CDI) is a subject of ongoing debate. With the aim of evaluating four laboratory diagnostic methods, 250 unformed stools from patients with suspected CDI submitted to nine medical center laboratories from November 2010 to December 2011, were studied using: (1) an immunochromatographic rapid assay test that combines the qualitative determination of glutamate dehydrogenase (GDH) plus toxins A and B (QAB), the CDIFF QUIK CHEK COMPLETE assay; (2) an enzyme immunoassay for qualitative determination of toxins A and B, the RIDASCREEN™ C. difficile Toxin A/B assay (RAB); (3) a PCR for the toxin B gene assay (PCR); and (4) the toxigenic culture (TC). C. difficile isolates from direct toxin negative stools by QAB, RAB and PCR were evaluated for toxigenicity by the same direct tests, in order to assess the contribution of the TC (QAB-TC, RAB-TC, PCR-TC). A combination of the cell culture cytotoxicity neutralization assay (CCCNA) in stools, and the same assay on isolates from direct negative samples (CCCNA-TC) was considered the reference method (CCCNA/CCCNA-TC). Of the 250 stools tested, 107 (42.8%) were positive by CCCNA/CCCNA-TC. The GDH and PCR/PCR-TC assays were the most sensitive, 91.59% and 87.62%, respectively. The QAB, RAB, QAB/QAB-TC and RAB/RAB-TC had the highest specificities, ca. 95%. A negative GDH result would rule out CDI, however, its low positive likelihood ratio (PLR) of 3.97 indicates that a positive result should always be complemented with the detection of toxins. If the RAB, QAB, and PCR assays do not detect toxins from direct feces, the toxigenic culture should be performed. In view of our results, the most accurate and reliable methods to be applied in a clinical microbiology laboratory were the QAB/QAB-TC, and RAB/RAB-TC, with PLRs >10 and negative likelihood ratios <0.30.
Assuntos
Toxinas Bacterianas , Clostridioides difficile , Técnicas Imunoenzimáticas , Reação em Cadeia da Polimerase , Proteínas de Bactérias , Toxinas Bacterianas/análise , Clostridioides difficile/genética , Enterotoxinas , Fezes , Humanos , Sensibilidade e EspecificidadeRESUMO
A taxonomically unique bacterial strain, Acinetobacter sp. A47, has been recovered from several soft tissue samples from a patient undergoing reconstructive surgery owing to a traumatic amputation. The results of 16S rRNA, rpoB, and gyrB gene comparative sequence analyses showed that A47 does not belong to any of the hitherto-known taxa and may represent an as-yet-unknown Acinetobacter species. The recognition of this novel organism contributes to our knowledge of the taxonomic complexity underlying infections caused by Acinetobacter.
Assuntos
Infecções por Acinetobacter , Acinetobacter/genética , Lesões dos Tecidos Moles , Acinetobacter/classificação , Acinetobacter/fisiologia , Infecções por Acinetobacter/diagnóstico , Infecções por Acinetobacter/microbiologia , DNA Bacteriano/análise , DNA Bacteriano/genética , Feminino , Genes Bacterianos/genética , Humanos , Pessoa de Meia-Idade , Dados de Sequência Molecular , Fenótipo , Lesões dos Tecidos Moles/diagnóstico , Lesões dos Tecidos Moles/microbiologiaRESUMO
A case is presented of a 64-year-old male patient who was admitted because of delirium, jaundice, a pattern of cholestasis in the liver profile and a right lung mass in the context of a constitutional syndrome and weight loss in the last eight months. The lung mass was punctured and the culture of the obtained material developed white colonies, identified by mass spectrometry (MALDI-TOF) as Nocardia cyriacigeorgica. Regarding the clinical diagnosis, it was considered as systemic lupus erythematosus (SLE), on the basis of fulfilling 8 criteria according to SLICC 2012 group, and 24 points according to EULAR/ACR 2019. The liver biopsy showed a mixt cellular infiltrate in portal spaces, with absence of interphase hepatitis and presence of peripheral ductular reaction. These findings were interpreted as liver compromise relate to SLE. Delirium was also considered as a neurological manifestation related to SLE on the basis of ruling out other causes. After being treated with antibiotics and documenting a reduction in the size of the lung mass he received cyclophosphamide in intravenous pulses, achieving normalization of his liver profile and his state of consciousness, and a progressively weight recovering. A year after he was in good health. The report of this case is justified because of the rare presenting form of late onset SLE, as well as the concomitant pulmonary nocardiosis in the absence of previous immunosuppressant treatment.
Se presenta el caso de un varón de 64 años que fue internado por delirium asociado a ictericia con patrón de colestasis en el hepatograma, y una masa en el pulmón derecho en el contexto de pérdida de peso y síndrome constitucional de 8 meses de evolución. Se realizó punción de la masa pulmonar cuyo cultivo desarrolló colonias blanquecinas identificadas como Nocardia cyriacigeorgica por espectrometría de masas (MALDI-TOF MS). Se llegó al diagnóstico de lupus eritematosos sistémico (LES) por presentar 8 de los criterios de acuerdo con el grupo SLICC 2012 y 24 puntos de acuerdo a los criterios EULAR/ACR 2019. La biopsia hepática mostró leve y variable infiltrado inflamatorio mixto en espacios porta, con ausencia de hepatitis de interfase y presencia de reacción ductular periférica. Se interpretaron estos hallazgos como vinculados a hepatopatía por LES. El delirium fue interpretado como afectación neurológica por LES en base al descarte de otras enfermedades. Recibió tratamiento antibiótico y tras constatarse reducción del tamaño de la masa pulmonar se administraron pulsos de ciclofosfamida intravenosa. Evolucionó favorablemente, con normalización del hepatograma y el estado de conciencia, y recuperación del peso en forma progresiva. Al año se lo encontró en buen estado de salud. Justifica el reporte del caso la rara forma de presentación del LES de comienzo tardío, así como la nocardiosis pulmonar concomitante sin tratamiento inmunosupresor previo.
Assuntos
Colestase , Delírio , Lúpus Eritematoso Sistêmico , Nocardiose , Humanos , Masculino , Pessoa de Meia-Idade , Lúpus Eritematoso Sistêmico/complicações , Nocardiose/diagnóstico , Nocardiose/complicações , Delírio/etiologia , Colestase/etiologia , Pneumopatias/microbiologiaRESUMO
We present a case of a 34-year-old patient with abdominal sepsis caused by an infrequent species: Chimaeribacter arupi. Genomic analysis confirmed the identification which is difficult to achieve by other methods so far. To our knowledge, this represents the first case of infection by this species reported in Argentina.
RESUMO
Members of the genus Phytobacter (order Enterobacterales) are isolated from the natural environment and clinical settings. Identification of Phytobacter strains based on biochemical characteristics is complicated due to taxonomic confusion, and they are often misidentified by automated identification systems in laboratories. In this study we describe the first three clinical cases associated with Phytobacter spp. reported in Argentina. We describe the identification, the molecular analysis using whole genome sequencing and the potential clinical relevance.
RESUMO
BACKGROUND: Corynebacterium spp. are widely disseminated in the environment, and they are part of the skin and mucosal microbiota of animals and humans. Reports of human infections by Corynebacterium spp. have increased considerably in recent years and the appearance of multidrug resistant isolates around the world has drawn attention. OBJECTIVES: To describe a new species of Corynebacterium from human tissue bone is described after being misidentified using available methods. METHODS: For taxonomic analyses, phylogenetic analysis of 16S rRNA and rpoB genes, in silico DNA-DNA hybridization, average nucleotide and amino acid identity, multilocus sequence analysis, and phylogenetic analysis based on the complete genome were used. FINDINGS: Genomic taxonomic analyzes revealed values of in silico DNA-DNA hybridization, average nucleotide and amino acids identity below the values necessary for species characterization between the analyzed isolates and the closest phylogenetic relative Corynebacterium aurimucosum DSM 44532T. MAIN CONCLUSIONS: Genomic taxonomic analyzes indicate that the isolates analyzed comprise a new species of the Corynebacterium genus, which we propose to name Corynebacterium hiratae sp. nov. with isolate 332T (= CBAS 826T = CCBH 35,014T) as the type strain.
Assuntos
Infecções por Corynebacterium , Corynebacterium , DNA Bacteriano , Filogenia , RNA Ribossômico 16S , Corynebacterium/genética , Corynebacterium/classificação , Corynebacterium/isolamento & purificação , Humanos , RNA Ribossômico 16S/genética , DNA Bacteriano/genética , Infecções por Corynebacterium/microbiologia , Osso e Ossos/microbiologia , Tipagem de Sequências Multilocus , Genoma Bacteriano , Técnicas de Tipagem Bacteriana , Hibridização de Ácido NucleicoRESUMO
The case of a 52-year-old female patient with a history of critical aortic stenosis, hypothyroidism and splenectomy as treatment for her Hodgkin's lymphoma is herein presented. In April 2011, the patient was admitted to the cardiology service due to global heart failure, fever and poor response to diuretic and vasodilator therapy. A transesophageal echocardiogram showed images compatible with vegetations in the aortic, pulmonary, and mitral valves. A diagnosis of infective endocarditis was made. Growth of gram-negative coccobacilli was observed in two blood culture sets. The microorganism was finally identified as Bordetella holmesii. The patient was treated with ceftriaxone 1 g every 12 hours for 28 days with favorable outcome.
Assuntos
Infecções por Bordetella , Endocardite Bacteriana/microbiologia , Complicações Pós-Operatórias/microbiologia , Esplenectomia , Endocardite Bacteriana/diagnóstico , Feminino , Humanos , Pessoa de Meia-Idade , Complicações Pós-Operatórias/diagnósticoRESUMO
Sixty-four colistin-resistant Klebsiella pneumoniae isolates recovered from clinical specimens from 57 patients admitted to Hospital de Clinicas Jose de San Martin during the period 2010-2012 were studied to describe the microbiological and epidemiological characteristics and factors associated with the emergence of colistin-resistance. Fifty-four colistin-susceptible K. pneumoniae isolates from the same period were also included in the study. The genetic relatedness among the isolates was studied by a PCR assay. Fifty percent of the resistant isolates were KPC-2 producers, 45.3% were ESBL producers and 4.7% only showed resistance to aminopenicilins. All KPC-producers (resistant and susceptible to colistin) were genotipically indistinguishable except for one, whereas the presence of 7 clonal types, which were different from the ones identified in the colistin-susceptible isolates, were detected among ESBL producers. The previous use of colistin was the main factor associated with the acquisition of resistance, and in the case of non-KPC producers the stay in ICU was another significant factor observed. Colistin resistance emerged in our hospital in the year 2010, reaching 3% in nosocomial isolates and maintaining this rate in successive years, due to the selection of resistant subpopulations in the epidemic clonal type in KPC-producers and due to the dispersion of colistin-resistant clonal types in non-KPC producing-isolates.