Resistance Profiles Of Pathogens Research Articles

A rare fungus on the rise: Candida auris.

An overview of the growing health threat posed by the fungus Candida auris is provided, including a review of the literature and Centers for Disease Control and Prevention recommendations on C. auris identification, treatment, and infection control. Since C. auris was first identified in Japan in 2009, cases of C. auris infection have been on the rise in several parts of the world, including the United States, where the first case was reported in 2017; as of November 2017, a total of 206 U.S. cases in 10 states had been reported. Risk factors for C. auris infection have been difficult to identify. However, catheterization, hospitalization, and recent surgery appear to be common factors in patients with C. auris infection. Major challenges in the management of C. auris infections include the common misidentification of C. auris using conventional laboratory techniques and the pathogen's resistance profile, which includes resistance to commonly used antifungals. These challenges may lead to breakdowns in timely implementation of infection-control and prevention measures. Antimicrobial stewardship can play a key role in the management and prevention of C. auris infections. C. auris is an emerging fungus that has the potential for causing serious invasive infections. The organism is resistant to commonly used antifungals and is difficult to identify with conventional laboratory techniques. Echinocandins are currently recommended as initial therapy for the treatment of C. auris infections in adults and children at least 2 months of age.

Semi-quantitative MALDI-TOF for antimicrobial susceptibility testing in Staphylococcus aureus.

Antibiotic resistant bacterial infections are a significant problem in the healthcare setting, in many cases requiring the rapid administration of appropriate and effective antibiotic therapy. Diagnostic assays capable of quickly and accurately determining the pathogen resistance profile are therefore crucial to initiate or modify care. Matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry (MS) is a standard method for species identification in many clinical microbiology laboratories and is well positioned to be applied towards antimicrobial susceptibility testing. One recently reported approach utilizes semi-quantitative MALDI-TOF MS for growth rate analysis to provide a resistance profile independent of resistance mechanism. This method was previously successfully applied to Gram-negative pathogens and mycobacteria; here, we evaluated this method with the Gram-positive pathogen Staphylococcus aureus. Specifically, we used 35 strains of S. aureus and four antibiotics to optimize and test the assay, resulting in an overall accuracy rate of 95%. Application of the optimized assay also successfully determined susceptibility from mock blood cultures, allowing both species identification and resistance determination for all four antibiotics within 3 hours of blood culture positivity.

The most appropriate therapeutic strategy for acute lower respiratory tract infections: a Delphi-based approach

Lower respiratory tract infections (LRTIs) cause high morbidity and mortality worldwide. Empiric therapy often base the choice of antibiotic treatment on antibacterial spectrum of the agent rather than on its pharmacological properties or the pathogen resistance profile. Inappropriate prescribing leads to therapeutic failure and antibiotic resistance, with increasing direct and indirect health costs. A consensus on appropriate prescribing in LRTI therapy was appraised by this Delphi exercise, based on a panel of 70 pulmonologists, coordinated by a Scientific Committee of nine experts in respiratory medical care. Full or very high consensus was reached on several issues, including the role of oral cephalosporins in first-line treatments of LRTIs and the appropriateness of cefditoren, with balanced spectrum and high intrinsic activity, in LRTI treatment. Evidence-based medicine approach and a comprehensive process of disease management, from diagnosis to therapy and follow-up, should guide antibiotic prescribing.

Susceptibility Profiles of Mycobacterium ulcerans Isolates to Streptomycin and Rifampicin in Two Districts of the Eastern Region of Ghana.

Background. Drug resistance is a major challenge in antibiotic chemotherapy. Assessing resistance profiles of pathogens constitutes an essential surveillance tool in the epidemiology and control of infectious diseases, including Buruli ulcer (BU) disease. With the successful definitive management of BU using rifampicin and streptomycin, little attention had been paid to monitoring emergence of resistant Mycobacterium ulcerans (M. ulcerans) isolates in endemic communities. This study investigated the susceptibility profiles of M. ulcerans isolates from two BU endemic areas in Ghana to streptomycin and rifampicin. Methods. The antibiotic susceptibility of seventy (70) M. ulcerans isolates to rifampicin and streptomycin was determined simultaneously at critical concentrations of 40 µg/mL and 4 µg/mL, respectively, by the Canetti proportion method. Results. Resistance to rifampicin was observed for 12 (17.1%) M. ulcerans isolates tested, whilst 2 (2.9%) showed resistance to streptomycin. None of the isolates tested showed dual resistance to both rifampicin and streptomycin. Conclusion. Outcomes from this study may not be reflective of all BU endemic communities; it, however, provides information on the resistance status of the isolates, which is useful for monitoring of M. ulcerans, as well as BU disease surveillance and control.

Epidemiology and antimicrobial susceptibility profiles of aerobic and facultative Gram-negative bacilli isolated from patients with intra-abdominal infections in the Asia–Pacific region: 2008 results from SMART (Study for Monitoring Antimicrobial Resistance Trends)

During 2008, the Study for Monitoring Antimicrobial Resistance Trends (SMART) collected 2370 unique aerobic and facultative Gram-negative bacilli associated with intra-abdominal infections (IAIs) from 32 centres in 11 countries in the Asia–Pacific region and tested their in vitro susceptibility to 12 antimicrobial agents using the Clinical and Laboratory Standards Institute (CLSI) broth microdilution method. Enterobacteriaceae comprised 88.1% of the isolates, of which Escherichia coli was the most commonly isolated species (47.2%). Very low susceptibility rates to ampicillin/sulbactam were noted, particularly from China (27.4%) and India (28.8%). High rates of extended-spectrum β-lactamase (ESBL)-producing E. coli and Klebsiella pneumoniae were observed in China (59.1% and 34.4%, respectively), India (61.2% and 46.8%, respectively) and Thailand (53.0% and 23.1%, respectively), particularly those causing hospital-associated IAIs. The persistently high rates of E. coli isolates non-susceptible to fluoroquinolones were alarming, especially in Thailand (>50%), China (≥70%) and India (>80%). Twenty percent of ESBL-producing E. coli and 10% of ESBL-producing K. pneumoniae were susceptible to ceftazidime based on the CLSI 2010 guidelines. Carbapenems were the most reliably active in vitro against Enterobacteriaceae. However, isolates of ESBL-producing K. pneumoniae exhibiting non-susceptibility to ertapenem (7.5%) and imipenem (1.9%) emerged, particularly from community-associated IAIs and those isolated from patients in intensive care units. Regular updates of epidemiology and antimicrobial resistance profiles of pathogens associated with IAIs as well as regional treatment guidelines are necessary to ensure optimal antimicrobial therapy.

Fast, simple, and low-cost test for drug-resistant pathogens

More and more pathogens, including protozoa and bacteria, show resistance against a growing number of drugs.1 Apart from the inconvenience for patients and the costs of unsuccessful use of medication, this trend increases the risk of spreading resistant pathogens through the population, leading to more patients and the risk of outbreaks of epidemics. If the resistance profile of the pathogen was known before medication is started, a correct choice for different medication could often be made. Thus only fast, cheap, and specific tests enabling the characterisation of the resistance profile of pathogens can revert these adverse effects.

Cultivar Mixtures for the Simultaneous Management of Multiple Diseases: Tan Spot and Leaf Rust of Wheat

ABSTRACT Because of differences in life histories between Puccinia triticina, a highly specialized, polycyclic, windborne pathogen with a shallow dispersal gradient, and Pyrenophora tritici-repentis, a residue-borne pathogen with a steep dispersal gradient, wheat mixtures are expected to be more effective at controlling leaf rust than tan spot. The objectives of this research were to determine the effect of two-cultivar mixtures with varying proportions and different pathogen resistance profiles on the severity of tan spot and leaf rust, to evaluate yield of the mixtures in the presence or absence of disease, and to directly compare the relative effectiveness of cultivar mixing for tan spot versus leaf rust. In a field experiment at two sites in Kansas over two growing seasons, winter wheat cvs. Jagger and 2145, which have differential resistance reactions to leaf rust and tan spot, each were planted in proportions of 0.25, 0.50, 0.75, and 1.00. Plots were inoculated with each pathogen alone, both pathogens, treated with a fungicide, or exposed to ambient conditions. For both diseases for all siteyears, severity decreased substantially on the susceptible cultivar as the proportion of that cultivar decreased in mixture. Mixtures were significantly more effective at reducing leaf rust than tan spot in three of four site-years. Mixtures generally yielded the same as the weighted mean of components in monoculture although, in two of three site-years, at least one fungicide-treated and one diseased mixture each yielded higher than expected values. Although this particular mixture produced only modest yield benefits, the potential for simultaneous reductions in tan spot and leaf rust was demonstrated.