Rapid and reliable identification of microorganisms in the clinical laboratory is essential for an early and accurate diagnosis guiding timely therapy. However, conventional methods are sometimes ...unreliable and show controversial outcomes. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) has been reported as a rapid and reliable method for identification of bacteria and fungi isolated from clinical samples. Members of the genus
Raoultella
are increasingly recognized as clinically relevant. There are difficulties in their identification at the species level since sequencing the 16S rRNA or the
rpo
B genes does not show conclusive results. The aim of this study has been to compare two MALDI-TOF MS systems (Vitek MS and Bruker Biotyper) with Vitek2 and API20E systems for differentiation of
Raoultella
species. A collection of 97 clinical isolates of
Raoultella
species was identified with Vitek MS, in parallel with Vitek2 and API, and finally with Bruker Biotyper. Among the two most widely used MALDI-TOF MS platforms, results obtained with Vitek MS were slightly superior to those obtained with the Bruker Biotyper system, with sensitivities and specificities of 98.9/57.9% and 98.8/37.0%, respectively. The current commercial phenotypic identification systems are not optimized for the identification of
Raoultella
species. Our results indicate that MALDI-TOF-based identification is more accurate and sensitive than that provided by phenotypic methods.
In liver transplant (LT) recipients, Pneumocystis jirovecii pneumonia (PJP) is most frequently reported before 1992 when immunosuppressive regimens were more intense. It is uncertain whether ...universal PJP prophylaxis is still applicable in the contemporary LT setting. We aimed to examine the incidence of PJP in LT recipients followed at our institution where routine prophylaxis has never been practiced and to define the prophylaxis strategies currently employed among LT units in Spain. All LT performed from 1990 to October 2019 were retrospectively reviewed and Spanish LT units were queried via email to specify their current prophylaxis strategy. During the study period, 662 LT procedures were carried out on 610 patients. Five cases of PJP were identified, with only one occurring within the first 6 months. The cumulative incidence and incidence rate were 0.82% and 0.99 cases per 1000 person transplant years. All LT units responded, the majority of which provide prophylaxis (80%). Duration of prophylaxis, however, varied significantly. The low incidence of PJP in our unprophylaxed cohort, with most cases occurring beyond the usual recommended period of prophylaxis, questions a one-size-fits-all approach to PJP prophylaxis. A significant heterogeneity in prophylaxis strategies exists among Spanish LT centres.
Matrix-assisted laser desorption-time of flight mass spectrometry (MALDI-TOF-MS) represents a revolution in the identification of microorganisms of clinical interest. Many studies have confirmed the ...accuracy and fastness of this tool with routine strains.
To identify clinical isolates of Candida from patients diagnosed with candidemia.
Vitek-MS™ system was used with a collection of 298 blood isolates of the genus Candida represented by 9 different species. Sequencing of the internal transcribed spacer (ITS) region of ribosomal DNA cluster was used as the reference method.
The results of Vitek-MS™ were concordant with those obtained with the reference method for 279 (93.62%) isolates (Kappa coefficient (κ)=0.91). Vitek-MS™ misidentified 10 (3.36%) isolates and did not identify 9 (3.02%) isolates.
This study determines the potential of Vitek-MS™ in yeast identification, being a reliable and fast alternative in the clinical laboratory, with an acceptable sensitivity of 82% (IC 95%: 70-90.6%), in comparison with a 100% (IC 95%: 92.9-100%) sensitivity of the conventional methods.
A multiplex-PCR (mPCR) assay was designed with species-specific primers which generate amplicons of 226bp, 434bp and 106bp for differentiating the species C. striatum, C. amycolatum, and C. xerosis, ...respectively. mPCR results were 100% in agreement with identifications achieved by 16S rRNA and rpoB gene sequencing and by VITEK-MS.
•Emerging pathogenic Corynebacterium species.•Multiplex PCR method based on species-distinctive genes.•Accurate identification of C. striatum, C. amycolatum and C. xerosis.
INTRODUCTIONAcinetobacter is a genus that comprises a group of opportunistic pathogens responsible for a variety of nosocomial infections. The Acinetobacter calcoaceticus-Acinetobacter baumannii ...(Acb) complex includes some species of clinical importance, mainly A. baumannii, A. pittii and A. nosocomialis, which share phenotypic similarities that make it very difficult to distinguish between them using a phenotypic approach. The aim of this study was to evaluate two commercial matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) systems for the identification of different Acinetobacter species, with a special focus among those belonging to the Acb complex. METHODSOne hundred and fifty-six Acinetobacter spp. clinical strains, identified by amplified ribosomal DNA restriction analysis (ARDRA) and rpoB gene sequencing, were analysed by two different MALDI-TOF systems. RESULTSConsidering only the 144 strains of the Acb complex evaluated in this study, the Vitek-MS™ and Microflex LT™ systems correctly identified 129 (89.6%) and 143 (99.3%) strains, respectively. CONCLUSIONAfter analysing 156 strains belonging to Acinetobacter spp., both Vitek-MS™ and Microflex LT™ proved to be rapid and accurate systems for the identification of Acb complex species showing a good correlation. However, both manufacturers should improve their databases to include new species in them.
We aimed to assess the percentage of azole resistance in Aspergillus fumigatus in Spain.
Thirty participating Spanish hospitals stored all morphologically identified A. fumigatus sensu lato clinical ...isolates—regardless their clinical significance—from 15 February to 14 May 2019. Isolates showing azole resistance according to the EUCAST 9.3.2 methodology were molecularly identified and the cyp51A gene was studied in A. fumigatus sensu stricto isolates.
Eight hundred and forty-seven isolates from 725 patients were collected in 29 hospitals (A. fumigatus sensu stricto (n = 828) and cryptic species (n = 19)). Isolates were mostly from the lower respiratory tract (94.0%; 797/847). Only cryptic species were amphotericin B resistant. Sixty-three (7.4%) out of the 847 isolates were resistant to ≥1 azole(s). Azole resistance was higher in cryptic species than in A. fumigatus sensu stricto (95%, 18/19 vs. 5.5%, 45/828); isavuconazole was associated to the lowest number of non-wild type isolates. The dominant mechanism of resistance was the presence of TR34-L98H substitutions (n = 24 out of 63). Out of the 725 patients, 48 (6.6%) carried either cryptic species (n = 14) or A. fumigatus sensu stricto (n = 34; 4.7%) resistant isolates. Aspergillus fumigatus sensu stricto harbouring either the TR34-L98H (n = 19) or TR46/Y121F/T289A (n = 1) mutations were detected in patients in hospitals located at 7/24 studied cities.
Of the patients, 6.6% carry azole-resistant A. fumigatus sensu lato isolates in Spain. TR34-L98H is the dominant cyp51A gene substitutions, although its presence is not widespread.
Virulence genes of Aeromonas spp. isolates from stool in Spain Ruiz de Alegría Puig, Carlos; Fernández Martínez, Marta; De Malet Pintos Fonseca, Ana
Enfermedades infecciosas y microbiologia clinica (English ed.),
12/2023, Volume:
41, Issue:
10
Journal Article
Peer reviewed
The role of Aeromonas species in gastrointestinal disease is controversial. The aim was to analyze not only the virulence genes between different species of Aeromonas isolated from feces, but the ...distribution of these virulence genes between enterotoxigenic strains and co-pathogen strains.
Retrospective study of isolates of Aeromonas spp. in feces (2016–2021). The protocol included coproculture, identification by MALDI-TOF and confirmation by multiplex PCR. SPSS Statistics program was used.
A total of 288 strains were studied for the virulence genes between different species of Aeromonas. To compare virulence genes between Aeromonas as co-pathogen and those isolated alone, 218 strains of the global set were used; 52 as co-pathogens compared with 166 Aeromonas without associated pathogen as controls.
We found no significant differences in the distribution of virulence genes versus co-existence of co-pathogens or not. A. hydrophila is the potentially most virulent species of our set.
El papel de las especies de Aeromonas en las enfermedades gastrointestinales es controvertido. El objetivo fue analizar no solo los genes de virulencia entre diferentes especies de Aeromonas aisladas de heces, sino también la distribución de estos genes de virulencia entre cepas enterotoxigénicas y co-patógenas.
Estudio retrospectivo de aislamientos de Aeromonas spp. en heces (2016-2021). El protocolo incluyó coprocultivo, identificación por MALDI-TOF y confirmación por PCR multiplex. Se utilizó el programa SPSS Statistics.
Se estudiaron un total de 288 cepas para los genes de virulencia entre diferentes especies de Aeromonas. Para comparar genes de virulencia entre Aeromonas como co-patógeno y los aislados únicos, se utilizaron 218 cepas del conjunto global; 52 como co-patógenos, comparados con 166 Aeromonas sin patógeno asociado como controles.
No se encontraron diferencias significativas en la distribución de los genes de virulencia versus coexistencia de co-patógenos o no. Aeromonas hydrophila es la especie potencialmente más virulenta de nuestro muestreo.
Introduction. The Autonomous Community of Galicia has adopted DECREE 216/2011 on health standards for poultry production, in addition to the Spanish national programs. However, no program has yet ...been implemented to eradicate campylobacteriosis, which shares the same reservoir. The aim of this study was to compare the evolution of Salmonella spp. isolates with respect to those of Campylobacter spp. in faecal samples received by the Microbiology Department. Material and methods. A retrospective descriptive comparative study was conducted through the Laboratory Information System (SIL) of Salmonella spp. isolated against Campylobacter spp. in faeces between 2011 and 2022 at the Lucus Augusti University Hospital (HULA), Lugo, Spain. Results. A total of 35,704 stool samples were analysed, of which 3,045 were positive. 751 Salmonella spp. were isolated. Statistical differences were observed in the annual distribution (p<0.01), with a clear turning point in 2018. Five hundred and five patients required hospital care, especially in 2014 with 72 patients (69%). On the other hand, 1,587 Campylobacter spp. were isolated. Required hospital care 1,002 patients during the study, with a peak in 2019 with 111 cases (62%) Conclusion. The reduction of salmonellosis cases and the maintenance of campylobacteriosis cases are directly related to the implementation of DECREE 216/2011. This, in turn, has reduced the pressure on hospitals in the HULA health area. Therefore, we believe that the ONE Health concept is being strengthened in the area studied.
The genus Aeromonas belongs to the Aeromonadaceae family. A patient with a pancreas–kidney transplant had multiple episodes of abdominal sepsis after surgery. Aeromonas hydrophila was isolated in the ...ascitic and biliary fluid drains. After discharge, the patient had several diarrhea episodes, and A. hydrophila was isolated in four stool samples. We decided to test whether the one strain that we initially isolated in ascitic fluid was the same that appeared in the successive stool samples. Five isolates of A. hydrophila were found in the patient. Identification was performed using the MALDI-TOF system and confirmed via multiplex PCR. The analysis of the REP-PCR fingerprint patterns showed one cluster and confirmed that all isolates were related. We also demonstrated the virulent character of this species associated with genes encoding different toxins (act, alt, ast, hlyA, and aerA). The virulence of this species is associated with the expression of genes that encode different toxins, structural proteins, and metal-associated proteins. This case report highlights the severity of this disease, especially in immunocompromised patients, and its adequate treatment.
The incidence of Campylobacter coli has increased and with greater resistance to antibiotics than Campylobacter jejuni.
To determine the epidemiology distribution of Campylobacter spp. in our health ...area, and the sensitivity to commonly tested antibiotics.
Retrospective descriptive study of cases of campylobacteriosis (2016–2020) recovered from stool cultures as laboratory routine protocol. Sensitivity was tested following EUCAST recommendations.
Of 1319 campylobacteriosis (C. jejuni 87.7%, C. coli 12.3%) we found a decrease in C. jejuni cases in 2019, and an increase in C. coli. Statistically significant differences were seen in age and gender distribution. The resistance percentages have generally decreased, with higher percentages of resistance in C. coli than in C. jejuni, being significant for erythromycin.
There is not an increase of C. jejuni and its resistance but there is a not alarming increase of incidence of C. coli and its resistance in our health area.
La incidencia de Campylobacter coli ha aumentado y con mayor resistencia a los antibióticos que Campylobacter jejuni.
Determinar la distribución epidemiológica de Campylobacter spp. en nuestra área de salud y la sensibilidad a los antibióticos comúnmente probados.
Estudio descriptivo retrospectivo de casos de campilobacteriosis (2016-2020) recuperados de coprocultivos con el protocolo de rutina del laboratorio. La sensibilidad se probó siguiendo las recomendaciones de EUCAST.
De 1.319 campilobacteriosis (C. jejuni 87,7%, C. coli 12,3%) se encontró una disminución en los casos de C. jejuni en 2019, y un aumento en C. coli. Se observaron diferencias estadísticamente significativas en la distribución de edad y género. Los porcentajes de resistencia han disminuido en general, con porcentajes más altos de resistencia en C. coli que en C. jejuni, siendo significativos para la eritromicina.
No hay un aumento de C. jejuni ni de su resistencia, pero sí un aumento no alarmante de la incidencia de C. coli y su resistencia en nuestra área de salud.
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