Acinetobacter sp: importància com a patogen nosocomial en l'actualitat

El gènere Acinetobacter està format per bacils gramnegatius immòbils àmpliament distribuïts en la natura. Des de la seva descripció, els membres d'aquest gènere han patit nombrosos canvis taxonòmics, en part a causa de l'absència de característiques bioquímiques diferencials. Els avenços en les tècniques d'hibridació d'àcid desoxiribonucleic (DNA) han permès la identificació de 21 grups o genoespècies dins del gènere Acinetobacter. La majoria de laboratoris de microbiologia clínica no disposen de tècniques genètiques, i per tant la identificació es basa en proves fenotípiques tradicionals com la utilització de carbohidrats, el creixement a diferents temperatures (37ºC, 41ºC i 44ºC) i l'hemòlisi, entre d'altres. La principal espèciemassociada a infecció és A. baumannii, mentre que altres espècies com A. Iwoffii o A. haemolyticus s'aïllen amb poca freqüència en les mostres clíniques

Clonal spread of Klebsiella pneumoniae producing OXA-1 betalactamase in a Spanish hospital

Multi-drug resistant Klebsiella pneumoniae isolates are associated with nosocomial infections, in which colonized patients act as a reservoir and source of cross-infection for other patients. In this study, the antimicrobial susceptibility of K. pneumoniae was tested by microdilution using the commercial method MicroScan (Siemens). The genetic relatedness of K. pneumoniae strains was determined by pulsed field gel electrophoresis (PFGE) and multilocus sequence typing (MLST). PCR experiments were carried out to obtain primer sets and positive PCR products were purified and sequenced. From May 2007 until December 2009, 98 clonally related K. pneumoniae isolates were detected from clinical samples of 38 patients admitted to the University Hospital of Bellvitge, Barcelona, Spain, including 27 admitted to the intensive care unit (ICU). The most important sources of the isolates were: lower respiratory tract (n = 12), urine (n = 12), and blood (n = 11). The strains were resistant to amoxicillin/clavulanic acid, piperacillin/tazobactam, tobramycin, amikacin, and ciprofloxacin, and had diminished susceptibility to cefepime. All the isolates shared a common PFGE pattern related to sequence type 14 after MLST analysis. In K. pneumoniae isolates and their transconjugants, the blaOXA-1 gene was located in the variable region of a class I integron that also contains the aac(6′)Ib-cr gene. Sequencing of the quinolone resistance determinant regions of gyrA and parC revealed a S83F change in GyrA and no changes in ParC. [Int Microbiol 2013; 16(4):227-233]Keywords: Klebsiella pneumoniae · sequence type ST14 · gene blaOXA-1 · integrons · nosocomial outbreak

Procediment de la prova antigènica de la COVID-19_Flowflex

Atenció primària; COVID-19; Prova antigènicaAtención primaria; COVID-19; Prueba antigénicaPrimary health care; COVID-19; Antigenic testL'objectiu d'aquest document és proporcionar els coneixements necessaris per realitzar la tècnica d'obtenció de l'antigen del SARS-CoV-2 de forma correcta i en un espai breu de temps.El objetivo de este documento es proporcionar los conocimientos necesarios para realizar la técnica de obtención del antígeno del SARS-CoV-2 de forma correcta y en un espacio breve de tiempo.The objective of this document is to provide the necessary knowledge to carry out the technique of obtaining the SARS-CoV-2 antigen correctly and in a short period of time

Risk Factors for Nosocomial Bacterremia Due to Methicillin-Resistant Staphylococcus Aureus

In a prospective surveillance study (February 1990–December 1991) performed at a 1000-bed teaching hospital to identify risk factors for nosocomial methicillin-resistantStaphylococcus aureus (MRSA) bacteremia, 309 patients were found to be colonized (n=103; 33 %) or infected (n=206; 67 %) by MRSA. Sixty-three of them developed bacteremia. Compared with 114 patients who had nosocomial bacteremia caused by methicillin-sensitiveStaphylococcus aureus during the same period of time, MRSA bacteremic patients had more severe underlying diseases (p<0.01), were more often in intensive care units (p<0.01) and had received prior antibiotic therapy more frequently (p<0.01). To further identify risk factors for MRSA bacteremia, univariate and multivariate analyses of this series of 309 patients were performed using the occurrence of MRSA bacteremia as the dependent variable. Among 14 variables analyzed, intravascular catheterization, defined as one or more intravascular catheters in place for more than 48 h, was the only variable selected by a logistic regression model as an independent risk factor (OR=2.7, CI=1.1–6.6). The results of this study reinforce the concept that recent antibiotic therapy may predispose patients to MRSA infection and suggest that among patients colonized or infected by MRSA, those with intravascular catheters are at high risk of developing MRSA bacteremia

Procediment de la prova antigènica de la COVID-19_Roche

Atenció primària; COVID-19; Prova antigènicaAtención primaria; COVID-19; Prueba antigénicaPrimary health care; COVID-19; Antigenic testL'objectiu d'aquest document és proporcionar els coneixements necessaris per a l'obtenció d'una determinació de l'antigen del SARS-CoV-2 de forma correcta i en un espai de temps breu.El objetivo de este documento es proporcionar los conocimientos necesarios para la obtención de una determinación del antígeno del SARSCoV-2 de forma correcta y en un espacio de tiempo breve.The objective of this document is to provide the necessary knowledge to obtain a determination of the SARSCoV-2 antigen correctly and in a short period of time

Clonal spread of Klebsiella pneumoniae producing OXA-1 betalactamase in a Spanish hospital

Multi-drug resistant Klebsiella pneumoniae isolates are associated with nosocomial infections, in which colonized patients act as a reservoir and source of cross-infection for other patients. In this study, the antimicrobial susceptibility of K. pneumoniae was tested by microdilution using the commercial method MicroScan (Siemens). The genetic relatedness of K. pneumoniae strains was determined by pulsed field gel electrophoresis (PFGE) and multilocus sequence typing (MLST). PCR experiments were carried out to obtain primer sets and positive PCR products were purified and sequenced. From May 2007 until December 2009, 98 clonally related K. pneumoniae isolates were detected from clinical samples of 38 patients admitted to the University Hospital of Bellvitge, Barcelona, Spain, including 27 admitted to the intensive care unit (ICU). The most important sources of the isolates were: lower respiratory tract (n = 12), urine (n = 12), and blood (n = 11). The strains were resistant to amoxicillin/clavulanic acid, piperacillin/tazobactam, tobramycin, amikacin, and ciprofloxacin, and had diminished susceptibility to cefepime. All the isolates shared a common PFGE pattern related to sequence type 14 after MLST analysis. In K. pneumoniae isolates and their transconjugants, the bla(OXA-1) gene was located in the variable region of a class I integron that also contains the aac(6')Ib-cr gene. Sequencing of the quinolone resistance determinant regions of gyrA and parC revealed a S83F change in GyrA and no changes in ParC

Procediment de la prova antigènica de la COVID-19_Biosynex

Atenció primària; COVID-19; Prova antigènica; BiosynexAtención primaria; COVID-19; Prueba antigénica; BiosynexPrimary health care; COVID-19; Antigenic test; BiosynexL'objectiu d'aquest procediment és proporcionar els coneixements necessaris per obtenir correctament una determinació de l'antigen del SARS-CoV-2 en un espai breu de temps.El objetivo de este procedimiento es proporcionar los conocimientos necesarios para obtener correctamente una determinación del antígeno del SARS-CoV-2 en un espacio breve de tiempo.The objective of this procedure is to provide the knowledge necessary to correctly obtain a determination of the SARS-CoV-2 antigen in a short period of time

Nosocomial Staphylococcus Aureus Bacterimia among Nasal Carriers of Methicillin- Resistant and Methicillin-Susceptible Strains

Objectives To determine the relevance of nasal carriage of Staphylococcus aureus, either methicillin-sensitive (MSSA) or methicillinresistant (MRSA), as a risk factor for the development of nosocomial S aureus bacteremia during an MRSA outbreak. patients and methods: In this prospective cohort study, 488 patients admitted to an intensive care unit (ICU) during a 1-year period were screened with nasal swabs within 48 hours of admission and weekly thereafter in order to identify nasal S aureus carriage. Nasal staphylococcal carriers were observed until development of S aureus bacteremia, ICU discharge, or death. Results One hundred forty-seven (30.1%) of 488 patients were nasal S aureus carriers; 84 patients (17.2%) harbored methicillin-sensitive S aureus; and 63 patients (12.9%) methicillinresistant S aureus. Nosocomial S aureus bacteremia was diagnosed in 38 (7.7%) of 488 patients. Rates of bacteremia were 24 (38%) of the MRSA carriers, eight (9.5%) of the MSSA carriers, and six (1.7%) of noncarriers. After adjusting for other predictors of bacteremia by means of a Cox proportional hazard regression model, the relative risk for S aureus bacteremia was 3.9 (95% confidence interval, 1.6–9.8; P = 0.002) for MRSA carriers compared with MSSA carriers. Conclusions Among ICU patients, nasal carriers of S aureus are at higher risk for S aureus bacteremia than are noncarriers; in the setting of an MRSA outbreak, colonization by methicillin-resistant strains represents a greater risk than does colonization by MSSA and strongly predicts the occurrence of MRSA bacteremia

Detection of the novel optrA gene among linezolid-resistant enterococci in Barcelona, Spain

The purpose of this study was to describe the presence of the novel optrA gene among clinical isolates of enterococci in a Spanish teaching hospital (May 2016-April 2017). optrA and cfr genes were screened by PCR in all isolates showing linezolid minimal inhibitory concentration (MIC) ≥4 mg/L. The genetic relatedness of the isolates, the presence of resistance and virulence genes, and the genetic environment of optrA were assessed by whole-genome sequencing (WGS). Six of 1,640 enterococci had linezolid MIC ≥4 mg/L. Among them, the optrA gene was detected in five Enterococcus faecalis isolated from unrelated patients. Although none of them had received linezolid or chloramphenicol, all had antecedents of recent quinolone consumption. WGS analysis revealed the existence of two different genotypes: ST585 and ST474. cfr was not detected in any of the isolates. No mutations were detected among the 23S ribosomal RNA and the ribosomal proteins L3, L4, and L22. Both genotypes also carried genes related to aminoglycoside, lincosamide, macrolide, phenicol, and tetracycline resistance. Detection of optrA in a setting with low linezolid consumption and among patients without antecedents of oxazolidinone therapy is of concern

Carbapenem-resistant and carbapenem-susceptible isogenic isolates of Klebsiella pneumoniae ST101 causing infection in a tertiary hospital

Background: In this study we describe the clinical and molecular characteristics of an outbreak due to carbapenem-resistant Klebsiella pneumoniae (CR-KP) producing CTX-M-15 and OXA-48 carbapenemase. Isogenic strains, carbapenem-susceptible K. pneumoniae (CS-KP) producing CTX-M-15, were also involved in the outbreak. Results: From October 2010 to December 2012 a total of 62 CR-KP and 23 CS-KP were isolated from clinical samples of 42 patients (22 had resistant isolates, 14 had susceptible isolates, and 6 had both CR and CS isolates). All patients had underlying diseases and 17 of them (14 patients with CR-KP and 3 with CS-KP) had received carbapenems previously. The range of carbapenem MICs for total isolates were: imipenem: 2 to >32 μg/ml vs. 32 μg/ml vs. 32 μg/ml vs. <2 μg/ml. All the isolates were also resistant to gentamicin, ciprofloxacin, and cotrimoxazole. Both types of isolates shared a common PFGE pattern associated with the multilocus sequence type 101 (ST101). The blaCTX-M-15 gene was detected in all the isolates, whereas the bla OXA-48 gene was only detected in CR-KP isolates on a 70 kb plasmid. Conclusions: The clonal spread of K. pneumoniae ST101 expressing the OXA-48 and CTX-M-15 beta-lactamases was the cause of an outbreak of CR-KP infections. CTX-M-15-producing isolates lacking the bla OXA-48 gene coexisted during the outbreak