The impact of methicillin-resistant Staphylococcus aureus in a neurosurgical unit: a growing problem

2003 ◽  
Vol 98 (1) ◽  
pp. 8-13 ◽  
Author(s):  
Kanna K. Gnanalingham ◽  
Ashraf Elsaghier ◽  
Christopher Kibbler ◽  
Colin Shieff
Keyword(s):  
Staphylococcus Aureus ◽  
Strict Adherence ◽  
Methicillin Resistant ◽  
Content Type ◽  
Surgical Wounds ◽  
Eradication Of Infection ◽  
Hospital Stays ◽  
Hospital Acquired ◽  
The Impact ◽  
Fine Print

Object. Methicillin-resistant Staphylococcus aureus (MRSA) infection is a growing problem worldwide. To investigate the severity of the problem, the authors surveyed the incidence of MRSA colonization and infection in the neurosurgical unit at their institution. Methods. Patients colonized or infected with MRSA who had been treated in the neurosurgical unit between 1993 and 1999 were retrospectively identified from laboratory records. There were 203 patients with MRSA-positive cultures, and the incidence of infection increased between 1993 (16 cases; 1.9% of admissions) and 1999 (60 cases; 6.7% of admissions). The mean duration of hospital stay was longer in patients with MRSA than in all patients treated in the unit (33.6 compared with 10.3 days, p < 0.001). Methicillin-resistant S. aureus was isolated from the nose in 89 patients, the throat in 79, the perineum in 52, surgical wounds in 16, sputum in 15, blood in 10, and from multiple sites in 69 patients. Fifty-six patients (28%) were infected with MRSA, and there were 15 deaths, of which three (20%) were likely to be due to the infection. The sources of MRSA included the neurosurgical ward in 84 patients, the intensive care unit in 28, other hospitals in 39, and the community in 17. The common strains of MRSA isolated were epidemic (E)MRSA-16 (110 cases) and EMRSA-15 (31 cases). The microorganism was eradicated in 16 cases, not eradicated in 20, and 167 patients were discharged from the hospital before eradication was achieved. All MRSA isolates were sensitive to vancomycin and teicoplanin and there was reduced sensitivity to mupirocin. Conclusions. Infection with MRSA is a growing problem in the neurosurgical population, and most cases are hospital-acquired and are associated with longer hospital stays. Asymptomatic colonization by this organism is far more common than infection of the surgical wound, although there is still morbidity due to MRSA sepsis. Most patients with MRSA are discharged before eradication of infection is achieved, thus increasing the risk that the infection will spread in the community. Strict adherence to the basic principles of infection control is the key to eradication of MRSA.

scholarly journals Linezolid Attenuates Lethal Lung Damage during Postinfluenza Methicillin-Resistant Staphylococcus aureus Pneumonia

2019 ◽  
Vol 87 (10) ◽  
Author(s):  
Atul K. Verma ◽  
Christopher Bauer ◽  
Vijaya Kumar Yajjala ◽  
Shruti Bansal ◽  
Keer Sun
Keyword(s):  
Staphylococcus Aureus ◽  
Therapeutic Effect ◽  
Critical Role ◽  
Lung Damage ◽  
Alpha Toxin ◽  
Methicillin Resistant ◽  
Content Type ◽  
Linezolid Therapy ◽  
Staphylococcus Aureus Pneumonia ◽  
The Impact

ABSTRACT Postinfluenza methicillin-resistant Staphylococcus aureus (MRSA) infection can quickly develop into severe, necrotizing pneumonia, causing over 50% mortality despite antibiotic treatments. In this study, we investigated the efficacy of antibiotic therapies and the impact of S. aureus alpha-toxin in a model of lethal influenza virus and MRSA coinfection. We demonstrate that antibiotics primarily attenuate alpha-toxin-induced acute lethality, even though both alpha-toxin-dependent and -independent mechanisms significantly contribute to animal mortality after coinfection. Furthermore, we found that the protein synthesis-suppressing antibiotic linezolid has an advantageous therapeutic effect on alpha-toxin-induced lung damage, as measured by protein leak and lactate dehydrogenase (LDH) activity. Importantly, using a Panton-Valentine leucocidin (PVL)-negative MRSA isolate from patient sputum, we show that linezolid therapy significantly improves animal survival from postinfluenza MRSA pneumonia compared with vancomycin treatment. Rather than improved viral or bacterial control, this advantageous therapeutic effect is associated with a significantly attenuated proinflammatory cytokine response and acute lung damage in linezolid-treated mice. Together, our findings not only establish a critical role of alpha-toxin in the extreme mortality of secondary MRSA pneumonia after influenza but also provide support for the possibility that linezolid could be a more effective treatment than vancomycin to improve disease outcomes.

scholarly journals Complete Genome Sequence of Hospital-Acquired Methicillin-Resistant Staphylococcus aureus Strain WCUH29

2019 ◽  
Vol 8 (23) ◽  
Author(s):  
Ting Lei ◽  
Ying Zhang ◽  
Junshu Yang ◽  
Kevin Silverstein ◽  
Yinduo Ji
Keyword(s):  
Staphylococcus Aureus ◽  
Genome Sequence ◽  
Complete Genome Sequence ◽  
Complete Genome ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
Model System ◽  
Aureus Strain ◽  
Methicillin Resistant ◽  
Content Type ◽  
Hospital Acquired

The hospital-acquired methicillin-resistant Staphylococcus aureus (HA-MRSA) strain WCUH29 has been intensively and widely used as a model system for identification and evaluation of novel antibacterial targets and pathogenicity. In this announcement, we report the complete genome sequence of HA-MRSA WCUH29 (NCIMB 40771).

scholarly journals Comparative Genomics of Vancomycin-Resistant Staphylococcus aureus Strains and Their Positions within the Clade Most Commonly Associated with Methicillin-Resistant S. aureus Hospital-Acquired Infection in the United States

mBio ◽  
2012 ◽  
Vol 3 (3) ◽  
Author(s):  
Veronica N. Kos ◽  
Christopher A. Desjardins ◽  
Allison Griggs ◽  
Gustavo Cerqueira ◽  
Andries Van Tonder ◽  
...  
Keyword(s):  
United States ◽  
Staphylococcus Aureus ◽  
The United States ◽  
Methicillin Resistant ◽  
Content Type ◽  
Mrsa Infection ◽  
Vancomycin Resistant ◽  
Foreign Dna ◽  
Mrsa Strains ◽  
Hospital Acquired

ABSTRACTMethicillin-resistantStaphylococcus aureus(MRSA) strains are leading causes of hospital-acquired infections in the United States, and clonal cluster 5 (CC5) is the predominant lineage responsible for these infections. Since 2002, there have been 12 cases of vancomycin-resistantS. aureus(VRSA) infection in the United States—all CC5 strains. To understand this genetic background and what distinguishes it from other lineages, we generated and analyzed high-quality draft genome sequences for all available VRSA strains. Sequence comparisons show unambiguously that each strain independently acquired Tn1546and that all VRSA strains last shared a common ancestor over 50 years ago, well before the occurrence of vancomycin resistance in this species. In contrast to existing hypotheses on what predisposes this lineage to acquire Tn1546, the barrier posed by restriction systems appears to be intact in most VRSA strains. However, VRSA (and other CC5) strains were found to possess a constellation of traits that appears to be optimized for proliferation in precisely the types of polymicrobic infection where transfer could occur. They lack a bacteriocin operon that would be predicted to limit the occurrence of non-CC5 strains in mixed infection and harbor a cluster of unique superantigens and lipoproteins to confound host immunity. A frameshift indprA, which in other microbes influences uptake of foreign DNA, may also make this lineage conducive to foreign DNA acquisition.IMPORTANCEInvasive methicillin-resistantStaphylococcus aureus(MRSA) infection now ranks among the leading causes of death in the United States. Vancomycin is a key last-line bactericidal drug for treating these infections. However, since 2002, vancomycin resistance has entered this species. Of the now 12 cases of vancomycin-resistantS. aureus(VRSA), each was believed to represent a new acquisition of the vancomycin-resistant transposon Tn1546from enterococcal donors. All acquisitions of Tn1546so far have occurred in MRSA strains of the clonal cluster 5 genetic background, the most common hospital lineage causing hospital-acquired MRSA infection. To understand the nature of these strains, we determined and examined the nucleotide sequences of the genomes of all available VRSA. Genome comparison identified candidate features that position strains of this lineage well for acquiring resistance to antibiotics in mixed infection.

scholarly journals Nasal Methicillin-Resistant Staphylococcus aureus (MRSA) PCR Testing Reduces the Duration of MRSA-Targeted Therapy in Patients with Suspected MRSA Pneumonia

2017 ◽  
Vol 61 (4) ◽  
Author(s):  
Nidhu Baby ◽  
Andrew C. Faust ◽  
Terri Smith ◽  
Lyndsay A. Sheperd ◽  
Laura Knoll ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Targeted Therapy ◽  
Length Of Hospital Stay ◽  
Serum Levels ◽  
Methicillin Resistant ◽  
Content Type ◽  
Before And After ◽  
Health Care Associated Pneumonia ◽  
The Impact ◽  
Suspected Pneumonia

ABSTRACT The objective of this study was to evaluate the impact of pharmacist-ordered methicillin-resistant Staphylococcus aureus (MRSA) PCR testing on the duration of empirical MRSA-targeted antibiotic therapy in patients with suspected pneumonia. This is a retrospective analysis of patients who received vancomycin or linezolid for suspected pneumonia before and after the implementation of a pharmacist-driven protocol for nasal MRSA PCR testing. Patients were included if they were adults of >18 years of age and initiated on vancomycin or linezolid for suspected MRSA pneumonia. The primary endpoint was the duration of vancomycin or linezolid therapy. After screening 368 patients, 57 patients met inclusion criteria (27 pre-PCR and 30 post-PCR). Baseline characteristics were similar between the two groups, with the majority of patients classified as having health care-associated pneumonia (68.4%). The use of the nasal MRSA PCR test reduced the mean duration of MRSA-targeted therapy by 46.6 h (74.0 ± 48.9 h versus 27.4 ± 18.7 h; 95% confidence interval [CI], 27.3 to 65.8 h; P < 0.0001). Fewer patients in the post-PCR group required vancomycin serum levels and dose adjustment (48.1% versus 16.7%; P = 0.02). There were no significant differences between the pre- and post-PCR groups regarding days to clinical improvement (1.78 ± 2.52 versus 2.27 ± 3.34; P = 0.54), length of hospital stay (11.04 ± 9.5 versus 8.2 ± 7.8; P = 0.22), or hospital mortality (14.8% versus 6.7%; P = 0.41). The use of nasal MRSA PCR testing in patients with suspected MRSA pneumonia reduced the duration of empirical MRSA-targeted therapy by approximately 2 days without increasing adverse clinical outcomes.

scholarly journals Impact of the Combination of Daptomycin and Trimethoprim-Sulfamethoxazole on Clinical Outcomes in Methicillin-Resistant Staphylococcus aureus Infections

2015 ◽  
Vol 59 (4) ◽  
pp. 1969-1976 ◽  
Author(s):  
Kimberly C. Claeys ◽  
Jordan R. Smith ◽  
Anthony M. Casapao ◽  
Ryan P. Mynatt ◽  
Lisa Avery ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Combination Therapy ◽  
Case Series ◽  
Signs And Symptoms ◽  
Retrospective Case ◽  
Methicillin Resistant ◽  
Content Type ◽  
Hospital Stays ◽  
Prolonged Hospital

ABSTRACTComplicatedStaphylococcus aureusinfections, including bacteremia, are often associated with treatment failures, prolonged hospital stays, and the emergence of resistance to primary and even secondary therapies. Daptomycin is commonly used as salvage therapy after vancomycin failure for the treatment of methicillin-resistantS. aureus(MRSA) infections. Unfortunately, the emergence of daptomycin resistance, especially in deep-seated infections, has been reported, prompting the need for alternative or combination therapy. Numerous antibiotic combinations with daptomycin have been investigated clinically andin vitro. Of interest, the combination of daptomycin and trimethoprim-sulfamethoxazole (TMP-SMX) has proved to be rapidly bactericidalin vitroto strains that are both susceptible and nonsusceptible to daptomycin. However, to date, there is limited clinical evidence supporting the use of this combination. This was a multicenter, retrospective case series of patients treated with the combination of daptomycin and TMP-SMX for at least 72 h. The objective of this study was to describe the safety and effectiveness of this regimen in clinical practice. The most commonly stated reason that TMP-SMX was added to daptomycin was persistent bacteremia and/or progressive signs and symptoms of infection. After the initiation of combination therapy, the median time to clearance of bacteremia was 2.5 days. Microbiological eradication was demonstrated in 24 out of 28 patients, andin vitrosynergy was demonstrated in 17 of the 17 recovered isolates. Further research with this combination is necessary to describe the optimal role and its impact on patient outcomes.

scholarly journals β-Lactams Enhance Vancomycin Activity against Methicillin-Resistant Staphylococcus aureus Bacteremia Compared to Vancomycin Alone

2013 ◽  
Vol 58 (1) ◽  
pp. 102-109 ◽  
Author(s):  
Thomas J. Dilworth ◽  
Omar Ibrahim ◽  
Pamela Hall ◽  
Jora Sliwinski ◽  
Carla Walraven ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Synergistic Activity ◽  
Methicillin Resistant ◽  
Content Type ◽  
Staphylococcus Aureus Bacteremia ◽  
High Incidence ◽  
The Difference ◽  
Initiation Of Therapy ◽  
The Impact

ABSTRACTVancomycin (VAN) is often used to treat methicillin-resistantStaphylococcus aureus(MRSA) bacteremia despite a high incidence of microbiological failure. Recentin vitroanalyses of β-lactams in combination with VAN demonstrated synergistic activity against MRSA. The goal of this study was to examine the impact of combination therapy with VAN and a β-lactam (Combo) on the microbiological eradication of MRSA bacteremia compared to VAN alone. This was a retrospective cohort study of patients with MRSA bacteremia who received Combo therapy or VAN alone. Microbiological eradication of MRSA, defined as a negative blood culture obtained after initiation of therapy, was used to evaluate the efficacy of each regimen. A total of 80 patients were included: 50 patients in the Combo group and 30 patients in the VAN-alone group. Microbiological eradication was achieved in 48 patients (96%) in the Combo group compared to 24 patients (80%) in the VAN-alone group (P= 0.021). In a multivariable model, the Combo treatment had a higher likelihood of achieving microbiological eradication (adjusted odds ratio, 11.24; 95% confidence interval, 1.7 to 144.3;P= 0.01). In patients with infective endocarditis (n= 22), 11/11 (100%) who received Combo therapy achieved microbiological eradication compared to 9/11 (81.8%) treated with VAN alone, but the difference was not statistically significant (P= 0.20). Patients with MRSA bacteremia who received Combo therapy were more likely to experience microbiological eradication of MRSA than patients who received VAN alone.

scholarly journals Impact of Antibiotic Treatment on the Burden of Nasal Staphylococcus aureus among Hospitalized Patients

2018 ◽  
Vol 62 (10) ◽  
Author(s):  
Anubhav Kanwar ◽  
Jennifer L. Cadnum ◽  
Annette L. Jencson ◽  
Curtis J. Donskey
Keyword(s):  
Staphylococcus Aureus ◽  
Antibiotic Treatment ◽  
Inhibitory Activity ◽  
Hospitalized Patients ◽  
Methicillin Resistant ◽  
Content Type ◽  
Treatment Regimens ◽  
Systemic Antibiotics ◽  
The Impact

ABSTRACT We examined the impact of systemic antibiotics on the burden of nasal Staphylococcus aureus in hospitalized patients. Of 1,482 patients, 237 (16%) had nasal methicillin-susceptible S. aureus (MSSA) and 92 (6%) had nasal methicillin-resistant S. aureus (MRSA) on admission. Treatment regimens that included agents with inhibitory activity against MRSA or MSSA significantly reduced the burden of carriage, whereas regimens lacking anti-MRSA activity, including fluoroquinolones, promoted MRSA overgrowth.

scholarly journals Role of the Stringent Stress Response in the Antibiotic Resistance Phenotype of Methicillin-Resistant Staphylococcus aureus

2016 ◽  
Vol 60 (4) ◽  
pp. 2311-2317 ◽  
Author(s):  
Sandra Aedo ◽  
Alexander Tomasz
Keyword(s):  
Staphylococcus Aureus ◽  
Stress Response ◽  
Phenotypic Expression ◽  
Beta Lactam ◽  
Resistance Level ◽  
Methicillin Resistant ◽  
Content Type ◽  
Resistance Phenotype ◽  
Oxacillin Resistance ◽  
The Impact

ABSTRACTResistance to beta-lactam antibiotics in methicillin-resistantStaphylococcus aureus(MRSA) requires the presence of an acquired genetic determinant,mecAormecC, which encode penicillin-binding protein PBP2A or PBP2A′, respectively. Although all MRSA strains share a mechanism of resistance, the phenotypic expression of beta-lactam resistance shows considerable strain-to-strain variation. The stringent stress response, a stress response that results from nutrient limitation, was shown to play a key role in determining the resistance level of an MRSA strain. In the present study, we validated the impact of the stringent stress response on transcription and translation ofmecAin the MRSA clinical isolate strain N315, which also carries known regulatory genes (mecI/mecR1/mecR2andblaI/blaR1) formecAtranscription. We showed that the impact of the stringent stress response on the resistance level may be restricted to beta-lactam resistance based on a “foreign” determinant such asmecA, as opposed to resistance based on mutations in the nativeS. aureusdeterminantpbpB(encoding PBP2). Our observations demonstrate that high-level resistance mediated by the stringent stress response follows the current model of beta-lactam resistance in which the native PBP2 protein is also essential for expression of the resistance phenotype. We also show that theStaphylococcus sciuri pbpDgene (also calledmecAI), the putative evolutionary precursor ofmecA, confers oxacillin resistance in anS. aureusstrain, generating a heterogeneous phenotype that can be converted to high and homogenous resistance by induction of the stringent stress response in the bacteria.

scholarly journals Convergent Adaptation in the Dominant Global Hospital Clone ST239 of Methicillin-Resistant Staphylococcus aureus

mBio ◽  
2015 ◽  
Vol 6 (2) ◽  
Author(s):  
Sarah L. Baines ◽  
Kathryn E. Holt ◽  
Mark B. Schultz ◽  
Torsten Seemann ◽  
Brian O. Howden ◽  
...  
Keyword(s):  
Health Care ◽  
Staphylococcus Aureus ◽  
Antimicrobial Agents ◽  
Health Care Environment ◽  
Methicillin Resistant ◽  
Content Type ◽  
Public Health Burden ◽  
Evolutionary Response ◽  
The Impact

ABSTRACTInfections caused by highly successful clones of hospital-associated methicillin-resistantStaphylococcus aureus(HA-MRSA) are a major public health burden. The globally dominant sequence type 239 (ST239) HA-MRSA clone has persisted in the health care setting for decades, but the basis of its success has not been identified. Taking a collection of 123 ST239 isolates spanning 32 years, we have used population-based functional genomics to investigate the evolution of this highly persistent and successful clone. Phylogenetic reconstruction and population modeling uncovered a previously unrecognized distinct clade of ST239 that was introduced into Australia from Asia and has perpetuated the epidemic in this region. Functional analysis demonstrated attenuated virulence and enhanced resistance to last-line antimicrobials, the result of two different phenomena, adaptive evolution within the original Australian ST239 clade and the introduction of a new clade displaying shifts in both phenotypes. The genetic diversity between the clades allowed us to employ genome-wide association testing and identify mutations in other essential regulatory systems, includingwalKR, that significantly associate with and may explain these key phenotypes. The phenotypic convergence of two independently evolving ST239 clades highlights the very strong selective pressures acting on HA-MRSA, showing that hospital environments have favored the accumulation of mutations in essential MRSA genes that increase resistance to antimicrobials, attenuate virulence, and promote persistence in the health care environment. Combinations of comparative genomics and careful phenotypic measurements of longitudinal collections of clinical isolates are giving us the knowledge to intelligently address the impact of current and future antibiotic usage policies and practices on hospital pathogens globally.IMPORTANCEMethicillin-resistantStaphylococcus aureus(MRSA) is responsible for innumerable drug-resistant health care-associated infections globally. This study, the first to investigate the evolutionary response of hospital-associated MRSA (HA-MRSA) over many decades, demonstrates how MRSA can persist in a region through the reintroduction of a previously unrecognized distinct clade. This study also demonstrates the crucial adaptive responses of HA-MRSA to the highly selective environment of the health care system, the evolution of MRSA isolates to even higher levels of antibiotic resistance at the cost of attenuated virulence. However,in vivopersistence is maintained, resulting in a clone of HA-MRSA able to resist almost all antimicrobial agents and still cause invasive disease in the heavily compromised hosts found in modern health care settings.

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