scholarly journals Methicillin-resistant S. aureus colonization in intensive care unit patients: Early identification and molecular typing

2016 ◽  
Vol 10 (05) ◽  
pp. 465-471 ◽  
Author(s):  
Gul Durmaz ◽  
Ozlem Sanci ◽  
Yasemin Oz ◽  
Kiymet Guven ◽  
Abdurrahman Kiremitci ◽  
...  

Introduction: Early detection of methicillin-resistant Staphylococcus aureus (MRSA) in colonized patients is very important for infection control procedures to prevent MRSA spread. We aimed to monitor MRSA carriage in intensive care unit (ICU) patients and to evaluate the speed and efficiency of conventional culture, immunological, chromogenic, and molecular methods together with genotyping. Methodology: Nasal and axillar swab specimens were obtained from patients in the ICUs of the general surgery and neurosurgery wards in a tertiary hospital once a week over four weeks between December 2009 and July 2010. Oxacillin and cefoxitin disk diffusion tests, oxacillin agar screening test, latex agglutination test, chromogenic agar, and real-time polymerase chain reaction (PCR) tests were used for isolation and identification of MRSA. MRSA isolates were typed using ribotyping and pulsed-field gel electrophoresis (PFGE) typing. Results: MRSA colonization was detected in 48 of 306 patients by real-time PCR. The MRSA colonization rate was 6.2%, 15.5%, and 38.5% at admission and in the first and second weeks, respectively. Sensitivity, specificity, positive and negative predictive values for all phenotypic tests were 98%, 99.6%, 98%, and 99.6%, respectively. The shortest handle time was observed in PCR. A total of three banding patterns were obtained from MRSA isolates by ribotyping, and PFGE analyses revealed 17 different pulsotypes varying from 11 to 18 distinct bands, showing high genetic diversity among the samples. Conclusion: Phenotypic MRSA screening tests in our study exhibited similar performances. The superiority of real-time PCR is its short turnaround time.

2020 ◽  
Author(s):  
AG Stewart ◽  
EP Price ◽  
K Schabacker ◽  
M Birikmen ◽  
PNA Harris ◽  
...  

AbstractThird-generation cephalosporin-resistant (3GC-R) Enterobacteriaceae represent a major threat to human health. Here, we captured 288 3GC-R Enterobacteriaceae clinical isolates from 258 patients presenting at a regional Australian hospital over a 14-month period. Alongside routine mass spectrometry speciation and antibiotic sensitivity testing, isolates were examined using a rapid (~40 min) pentaplex real-time PCR assay targeting the most common extended spectrum β-lactamases (ESBLs; CTX-M-1 and CTX-M-9 groups, plus TEM, SHV, and an internal 16S ribosomal DNA control). Additionally, AmpC CMY β-lactamase prevalence was examined using a singleplex PCR. A subset of isolates, including all 3GC-R isolates obtained from the intensive care unit, were subjected to whole-genome sequencing (WGS) to assess transmission dynamics, the presence of unidentified resistance determinants, and genotyping accuracy. Escherichia coli (80.2%) and Klebsiella pneumoniae (17.0%) were dominant, with Klebsiella oxytoca, Klebsiella aerogenes and Enterobacter cloacae infrequently identified. Ceftriaxone and cefoxitin resistance was identified in 97% and 24.5% of E. coli and K. pneumoniae isolates, respectively. Consistent with global findings in Enterobacteriaceae, the majority (98.3%) of isolates harbored at least one β-lactamase gene, with 144 (50%) encoding blaCTX-M-1 group, 92 (31.9%) blaCTX-M-9 group, 48 (16.7%) blaSHV, 133 (46.2%) blaTEM, and 34 (11.8%) blaCMY. WGS of β-lactamase negative or carbapenem-resistant isolates identified uncommon ESBLs and carbapenemases, including blaNDM and blaIMP, and confirmed all PCR-positive genotypes. No evidence of transmission among intensive care unit patients was identified. We demonstrate that our PCR assays enable the rapid and cost-effective identification of ESBLs in the hospital setting, which has important infection control and therapeutic implications.


2006 ◽  
Vol 27 (6) ◽  
pp. 581-585 ◽  
Author(s):  
Mary L. Bertin ◽  
Joan Vinski ◽  
Steven Schmitt ◽  
Camille Sabella ◽  
Lara Danziger-Isakov ◽  
...  

Objective.To describe the investigation and interventions necessary to contain an outbreak of methicillin-resistant Staphylococcus aureus (MRSA) colonization and infection in a neonatal intensive care unit (NICU).Design.Retrospective case finding that involved prospective performance of surveillance cultures for detection of MRSA and molecular typing of MRSA by repetitive-sequence polymerase chain reaction (rep-PCR).Setting.Level III NICU in a tertiary care center.Participants.Three neonates in a NICU were identified with MRSA bloodstream infection on April 16, 2004. A point prevalence survey identified 6 additional colonized neonates (attack rate, 75% [9 of 12 neonates]). The outbreak strain was phenotypically unusual.Interventions.Cohorting and mupirocin therapy were initiated for neonates who had acquired MRSA during the outbreak. Contact precautions were introduced in the NICU, and healthcare workers (HCWs) were retrained in cleaning and disinfection procedures and hand hygiene. Noncolonized neonates and newly admitted patients had surveillance cultures performed 3 times per week.Results.Two new colonized neonates were identified 1 month later. HCW X, who had worked in the NICU since June 2003, was identified as having chronic otitis. MRSA was isolated from cultures of swab specimens from HCW X's ear canal and nares. HCW X was epidemiologically linked to the outbreak. Molecular typing (by rep-PCR) confirmed that the isolates from HCW X and from the neonates were more than 90% similar. Retrospective review of NICU isolates revealed that the outbreak strain was initially cultured from a neonate 2 months after HCW X began working on the unit. The epidemic strain was eradicated after removing HCW X from patient care in the NICU.Conclusion.An outbreak of MRSA colonization and infection in a NICU was epidemiologically linked to a HCW with chronic otitis externa and nasal colonization with MRSA. Eradication was not achieved until removal of HCW X from the NICU. Routine surveillance for MRSA may have allowed earlier recognition of the outbreak and is now standard practice in our NICU.


2013 ◽  
Vol 34 (7) ◽  
pp. 748-750 ◽  
Author(s):  
Victor O. Popoola ◽  
Pranita Tamma ◽  
Nicholas G. Reich ◽  
Trish M. Perl ◽  
Aaron M. Milstone

We studied methicillin-resistant Staphylococcus aureus (MRSA)-colonized children with multiple intensive care unit (ICU) admissions to assess the persistence of MRSA colonization. Our data found that children with more than 1 year between ICU admissions had a higher prevalence of MRSA colonization than the overall ICU population, which supports empirical contact precautions for children with previous MRSA colonization.


2014 ◽  
Vol 69 (11) ◽  
pp. 3134-3141 ◽  
Author(s):  
J. Fortun ◽  
Y. Meije ◽  
M. J. Buitrago ◽  
S. Gago ◽  
L. Bernal-Martinez ◽  
...  

2011 ◽  
Vol 32 (4) ◽  
pp. 398-400 ◽  
Author(s):  
Patrick J. Myers ◽  
John Marcinak ◽  
Michael Z. David ◽  
Diana L. Zychowski ◽  
Susan Boyle-Vavra ◽  
...  

In response to epidemic methicillin-resistant Staphylococcus aureus (MRSA) in the community, the Illinois General Assembly mandated that all patients admitted to intensive care units statewide be screened for MRSA. Screening was instituted at our neonatal intensive care unit (NICU) in September 2007 by a polymerase chain reaction (PCR)-based strategy. The law created an opportunity to determine the rate of MRSA colonization among neonates, to gather information about subsequent MRSA infections, and to evaluate risk factors for MRSA colonization on admission to the NICU.


2018 ◽  
Vol 21 (2) ◽  
pp. 190-197
Author(s):  
Elena Ochotorena ◽  
Juan José Hernández Morante ◽  
Rubén Cañavate ◽  
Roberto Andrés Villegas ◽  
Inmaculada Viedma

Introduction and Objectives: Methicillin-resistant Staphylococcus aureus (MRSA) is the most prevalent pathogen causing nosocomial infections in hospitals and health centers. This work is an effort to understand the epidemiology of MRSA and other multidrug-resistant pathogens in an intensive care unit (ICU) and to analyze characteristics that might determine the risk of MRSA colonization/infection in this unit. Method: An observational, 1-year prospective longitudinal study was conducted to obtain information about MRSA and other multidrug-resistant colonizations/infections. The study was conducted with ICU patients with an artificial airway. Data were obtained from the National Study of the Control of Nosocomial Infections in Intensive Care Units database. Results: MRSA colonization was highly prevalent (33%); however, other pathogens like gram(−) Bacillus showed a higher infectious potency. Acute Physiology and Chronic Health Evaluation (APACHE-II) score >15 and hospital stay of >4 days were the main variables that significantly predicted the risk of developing MRSA colonization ( p < .001 in both cases). Moreover, the presence of MRSA increased the risk of developing a second multidrug-resistant colonization/infection, especially with methicillin-resistant Pseudomona. Discussion: The high prevalence of MRSA emphasizes the need to continue studying risk factors for MRSA colonization/infection, which may allow early identification of this pathogen. Therefore, we propose the use of the APACHE-II score and length of hospital stay to predict increased risk of MRSA colonization. Awareness of the heightened risk in particular patients could lead to early detection and prevention.


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