Ciprofloxacin Resistance among Nosocomial Pseudomonas aeruginosa and Staphylococcus aureus in the United States

1995 ◽  
Vol 16 (11) ◽  
pp. 620-621 ◽  
Author(s):  
Henry M. Blumberg ◽  
David Rimland ◽  
Robert Gaynes
mBio ◽  
2020 ◽  
Vol 11 (3) ◽  
Author(s):  
Eryn E. Bernardy ◽  
Robert A. Petit ◽  
Vishnu Raghuram ◽  
Ashley M. Alexander ◽  
Timothy D. Read ◽  
...  

ABSTRACT Staphylococcus aureus has recently overtaken Pseudomonas aeruginosa as the most commonly recognized bacterial pathogen that infects the respiratory tracts of individuals with the genetic disease cystic fibrosis (CF) in the United States. Most studies of S. aureus in CF patient lung infections have focused on a few isolates, often exclusively laboratory-adapted strains, and how they are killed by P. aeruginosa. Less is known about the diversity of S. aureus CF patient lung isolates in terms of both their virulence and their interaction with P. aeruginosa. To begin to address this gap, we recently sequenced 64 clinical S. aureus isolates and a reference isolate, JE2. Here, we analyzed the antibiotic resistance genotypes, sequence types, clonal complexes, spa types, agr types, and presence/absence of other known virulence factor genes of these isolates. We hypothesized that virulence phenotypes of S. aureus, namely, toxin production and the mucoid phenotype, would be lost in these isolates due to adaptation in the CF patient lung. In contrast to these expectations, we found that most isolates can lyse both rabbit and sheep blood (67.7%) and produce polysaccharide (69.2%), suggesting that these phenotypes were not lost during adaptation to the CF lung. We also identified three distinct phenotypic groups of S. aureus based on their survival in the presence of nonmucoid P. aeruginosa laboratory strain PAO1 and its mucoid derivative. Altogether, our work provides greater insight into the diversity of S. aureus isolates from CF patients, specifically the distribution of important virulence factors and their interaction with P. aeruginosa, all of which have implications in patient health. IMPORTANCE Staphylococcus aureus is now the most frequently detected recognized pathogen in the lungs of individuals who have cystic fibrosis (CF) in the United States, followed closely by Pseudomonas aeruginosa. When these pathogens are found to coinfect the CF lung, patients have a significantly worse prognosis. While P. aeruginosa has been rigorously studied in the context of bacterial pathogenesis in CF, less is known about S. aureus. Here, we present an in-depth study of 64 S. aureus clinical isolates from CF patients, for which we investigated genetic diversity utilizing whole-genome sequencing, virulence phenotypes, and interactions with P. aeruginosa. We found that S. aureus isolated from CF lungs are phylogenetically diverse; most retain known virulence factors and vary in their interactions with P. aeruginosa (i.e., they range from being highly sensitive to P. aeruginosa to completely tolerant to it). Deepening our understanding of how S. aureus responds to its environment and other microbes in the CF lung will enable future development of effective treatments and preventative measures against these formidable infections.


2019 ◽  
Vol 71 (7) ◽  
pp. 1676-1683 ◽  
Author(s):  
Daniel J Morgan ◽  
Min Zhan ◽  
Michihiko Goto ◽  
Carrie Franciscus ◽  
Bruce Alexander ◽  
...  

Abstract Background Methicillin-resistant Staphylococcus aureus (MRSA) is a common cause of health care–associated infections in long-term care facilities (LTCFs). The Centers for Disease Control and Prevention recommends contact precautions for the prevention of MRSA within acute care facilities, which are being used within the United States Department of Veterans Affairs (VA) for LTCFs in a modified fashion. The impact of contact precautions in long-term care is unknown. Methods To evaluate whether contact precautions decreased MRSA acquisition in LTCFs, compared to standard precautions, we performed a retrospective effectiveness study (pre-post, with concurrent controls) using data from the VA health-care system from 1 January 2011 until 31 December 2015, 2 years before and after a 2013 policy recommending a more aggressive form of contact precautions. Results Across 75 414 patient admissions from 74 long-term care facilities in the United States, the overall unadjusted rate of MRSA acquisition was 2.6/1000 patient days. Patients were no more likely to acquire MRSA if they were cared for using standard precautions versus contact precautions in a multivariable, discrete time survival analysis, controlling for patient demographics, risk factors, and year of admission (odds ratio, 0.97; 95% confidence interval, .85–1.12; P = .71). Conclusions MRSA acquisition and infections were not impacted by the use of active surveillance and contact precautions in LTCFs in the VA.


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