Staphylococcus aureus
is an important cause of surgical-site infections. In this randomized trial, eradication of colonization by rapid screening at admission and subsequent decolonization (with ...intranasal mupirocin and chlorhexidine skin washes) were associated with a decrease in postoperative surgical-site infections.
In this randomized trial, eradication of colonization with
S. aureus
by rapid screening at admission and subsequent decolonization (with intranasal mupirocin and chlorhexidine skin washes) were associated with a decrease in postoperative surgical-site infections.
Nasal carriers of high numbers of
Staphylococcus aureus
organisms have a risk of health care–associated infection with this microorganism that is three to six times the risk among noncarriers and low-level carriers.
1
–
3
More than 80% of health care–associated
S. aureus
infections are endogenous.
4
–
6
Intranasal application of mupirocin has been shown to be effective for the decolonization of this microbe and the prevention of invasive
S. aureus
infections in patients receiving long-term dialysis treatment.
7
–
10
However, in other nonsurgical patients, mupirocin had no effect on the rate of health care–associated
S. aureus
infections.
11
Mupirocin nasal ointment was reported to . . .
Antimicrobial susceptibility testing (AST) technologies help to accelerate the initiation of targeted antimicrobial therapy for patients with infections and could potentially extend the lifespan of ...current narrow-spectrum antimicrobials. Although conceptually new and rapid AST technologies have been described, including new phenotyping methods, digital imaging and genomic approaches, there is no single major, or broadly accepted, technological breakthrough that leads the field of rapid AST platform development. This might be owing to several barriers that prevent the timely development and implementation of novel and rapid AST platforms in health-care settings. In this Consensus Statement, we explore such barriers, which include the utility of new methods, the complex process of validating new technology against reference methods beyond the proof-of-concept phase, the legal and regulatory landscapes, costs, the uptake of new tools, reagent stability, optimization of target product profiles, difficulties conducting clinical trials and issues relating to quality and quality control, and present possible solutions.
Summary
Candida auris is an emerging antifungal resistant yeast species causing nosocomial and invasive infections, emphasising the need of improved diagnostics and epidemiological typing methods. We ...show that MALDI‐TOF VITEK‐MS followed by amplified length polymorphisms allows for accurate species identification and subsequent epidemiological characterisation of strains encountered during potential outbreaks.
Abstract
Background
Recent years have witnessed the development of several k-mer–based approaches aiming to predict phenotypic traits of bacteria on the basis of their whole-genome sequences. While ...often convincing in terms of predictive performance, the underlying models are in general not straightforward to interpret, the interplay between the actual genetic determinant and its translation as k-mers being generally hard to decipher.
Results
We propose a simple and computationally efficient strategy allowing one to cope with the high correlation inherent to k-mer–based representations in supervised machine learning models, leading to concise and easily interpretable signatures. We demonstrate the benefit of this approach on the task of predicting the antibiotic resistance profile of a Klebsiella pneumoniae strain from its genome, where our method leads to signatures defined as weighted linear combinations of genetic elements that can easily be identified as genuine antibiotic resistance determinants, with state-of-the-art predictive performance.
Conclusions
By enhancing the interpretability of genomic k-mer–based antibiotic resistance prediction models, our approach improves their clinical utility and hence will facilitate their adoption in routine diagnostics by clinicians and microbiologists. While antibiotic resistance was the motivating application, the method is generic and can be transposed to any other bacterial trait. An R package implementing our method is available at https://gitlab.com/biomerieux-data-science/clustlasso.
We define the epidemiology of predominant and sporadic methicillin-resistant Staphylococcus aureus (MRSA) strains in a central teaching and referral hospital in Kuala Lumpur, Malaysia. This is done ...on the basis of spa sequencing, multilocus sequence typing (MLST), staphylococcal cassette chromosome mec (SCCmec) typing, and virulence gene profiling. During the period of study, the MRSA prevalence was 44.1%, and 389 MRSA strains were included. The prevalence of MRSA was found to be significantly higher in the patients of Indian ethnicity (P < 0.001). The majority (92.5%) of the isolates belonged to ST-239, spa type t037, and possessed the type III or IIIA SCCmec. The arginine catabolic mobile element (ACME) arcA gene was detected in three (1.05%) ST-239 isolates. We report the first identification of ACME arcA gene-positive ST-239. Apart from this predominant clone, six (1.5%) isolates of ST-22, with two related spa types (t032 and t4184) and a singleton (t3213), carrying type IVh SCCmec, were detected for the first time in Asia. A limited number of community-acquired (CA) MRSA strains were also detected. These included ST-188/t189 (2.1%), ST-1/t127 (2.3%), and ST-7/t091 (1%). Panton-Valentin leukocidin (PVL) was detected in all ST-1 and ST-188 strains and in 0.7% of the ST-239 isolates. The majority of the isolates carried agr I, except that ST-1 strains were agr III positive. Virulence genes seg and sei were seen only among ST-22 isolates. In conclusion, current results revealed the predominance of ST-239-SCCmec III/IIIA and the penetration of ST-22 with different virulence gene profiles. The emergence in Malaysia of novel clones of known epidemic and pathogenic potential should be taken seriously.
Staphylococcus aureus is a persistent companion bacterial species in one-third of humankind. Reservoirs include the nasal and nasopharyngeal cavities, skin, and gastrointestinal (GI) tract. Despite ...earlier claims that colonization of individuals is caused by clonal organisms, next-generation sequencing (NGS) has revealed that resident type heterogeneity is not exceptional. Carriage, whether overt or hidden, is correlated with a risk of autoinfection. In a recent article in mBio, it was shown that, based on staphylococcal genome sequencing, low-level GI persistence may cause long-term nosocomial outbreaks L. Senn et al., 7(1):e02039-15, 2016, doi:10.1128/mBio.02039-15. Institutional endemicity with methicillin-resistant S. aureus (MRSA) sequence type 228 (ST228) is shown to originate not from high-level nasal carriage or poor compliance with infection control practice but from low-grade asymptomatic GI colonization. This shows the power of NGS in elucidating staphylococcal epidemiology and, even more important, demonstrates that (drug-resistant) microorganisms may possess stealthy means of persistence. Identifying these persistence mechanisms is key to successful infection control.
All bacterial genomes contain multiple loci of repetitive DNA. Repeat unit sizes and repeat sequences may vary when multiple loci are considered for different isolates of an individual microbial ...species. Moreover, it has been documented on many occasions that the number of repeat units per locus is a strain-defining parameter. Consequently, there is isolate-specificity in the number of repeats per locus when different strains of a given bacterial species are compared. The experimental assessment of this variability for a number of different loci has been called 'multilocus variable number of tandem repeat analysis' (MLVA). The approach can be supported or extended by locus-specific DNA sequencing for establishing mutations in the individual repeat units, which usually enhances the resolution of the approach considerably. Essentially, MLVA with or without supportive sequencing has been developed for all of the medically relevant bacterial species and can be used effectively for tracing outbreaks or other forms of bacterial dissemination. MLVA is a modern, timely and versatile bacterial typing methodology.
Abstract
Background
Antimicrobial susceptibility testing (AST) is classically performed using growth-based techniques that essentially require viable bacterial matter to become visible to the naked ...eye or a sophisticated densitometer.
Content
Technologies based on the measurement of bacterial density in suspension have evolved marginally in accuracy and rapidity over the 20th century, but assays expanded for new combinations of bacteria and antimicrobials have been automated, and made amenable to high-throughput turn-around. Over the past 25 years, elevated AST rapidity has been provided by nucleic acid-mediated amplification technologies, proteomic and other “omic” methodologies, and the use of next-generation sequencing. In rare cases, AST at the level of single-cell visualization was developed. This has not yet led to major changes in routine high-throughput clinical microbiological detection of antimicrobial resistance.
Summary
We here present a review of the new generation of methods and describe what is still urgently needed for their implementation in day-to-day management of the treatment of infectious diseases.
The identification of mycobacteria outside biocontainment facilities requires that the organisms first be rendered inactive. Exposure to 70% ethanol (EtOH) either before or after mechanical ...disruption was evaluated in order to establish a safe, effective, and rapid inactivation protocol that is compatible with identification of Mycobacterium and Nocardia species using matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS). A combination of 5 min of bead beating in 70% EtOH followed by a 10-min room temperature incubation period was found to be rapidly bactericidal and provided high-quality spectra compared to spectra obtained directly from growth on solid media. The age of the culture, the stability of the refrigerated or frozen lysates, and freeze-thaw cycles did not adversely impact the quality of the spectra or the identification obtained.
Background. Persistent nasal carriers have an increased risk of Staphylococcus aureus infection, whereas intermittent carriers and noncarriers share the same low risk. This study was performed to ...provide additional insight into staphylococcal carriage types. Methods. Fifty‐one volunteers who had been decolonized with mupirocin treatment and whose carriage state was known were colonized artificially with a mixture of S. aureus strains, and intranasal survival of S. aureus was compared between carriage groups. Antistaphylococcal antibody levels were also compared among 83 carriage‐classified volunteers. Results. Persistent carriers preferentially reselected their autologous strain from the inoculum mixture (P=.02). They could be distinguished from intermittent carriers and noncarriers on the basis of the duration of postinoculation carriage (154 vs. 14 and 4 days, respectively; P=.017, by log‐rank test). Cultures of swab samples from persistent carriers contained significantly more colony‐forming units per sample than did cultures of swab samples from intermittent carriers and noncarriers (P=.004). Analysis of serum samples showed that levels of immunoglobulin G and immunoglobulin A to 17 S. aureus antigens were equal in intermittent carriers and noncarriers but not in persistent carriers. Conclusions. Along with the previously described low risk of infection, intermittent carriers and noncarriers share similar S. aureus nasal elimination kinetics and antistaphylococcal antibody profiles. This implies a paradigm shift; apparently, there are only 2 types of nasal carriers: persistent carriers and others. This knowledge may increase our understanding of susceptibility to S. aureus infection.
PDF
