scholarly journals Soft Salt-Mannitol Agar–Cloxacillin Test: a Highly Specific Bedside Screening Test for Detection of Colonization with Methicillin-Resistant Staphylococcus aureus

1998 ◽  
Vol 36 (4) ◽  
pp. 986-989 ◽  
Author(s):  
Nuria Mir ◽  
Miguel Sánchez ◽  
Fernando Baquero ◽  
Blanca López ◽  
Celia Calderón ◽  
...  
Keyword(s):  
Intensive Care Unit ◽  
Staphylococcus Aureus ◽  
Intensive Care ◽  
Predictive Value ◽  
Color Change ◽  
False Negative ◽  
Clinical Samples ◽  
Methicillin Resistant ◽  
Negative Results ◽  
False Negative Results

The early detection of colonization with methicillin-resistantStaphylococcus aureus (MRSA) of patients in intensive-care units is an essential step in the strategy for preventing MRSA epidemics. In this study, tubes containing soft salt-mannitol agar with cloxacillin (6 μg/ml) (SSMAC) were prepared for inoculation of clinical samples at patients’ bedsides by personnel of an intensive-care unit. A total of 1,914 swabs from different sample sites of 81 patients were dipped into SSMAC tubes, and after 24 h of incubation (in an incubator located near the intensive-care unit), an evident color change was considered by the intensive-care-unit personnel to be an MRSA alarm. Sixty-three (3.3%) SSMAC tubes were considered positive for MRSA, 1,827 (95.4%) were considered negative, and 24 (1.2%) were considered intermediate. Compared with values for parallel conventional surveillance cultures for MRSA, excluding tubes with intermediate results, the SSMAC test had a sensitivity of 72.7%, a specificity of 99.2%, a positive predictive value of 76.2%, and a negative predictive value of 99.0%. When intermediate tubes were considered positive, the corresponding values were 75.3, 98.2, 63.2, and 99.0%, respectively. The sensitivity and specificity values of the test to identify MRSA-colonized patients were 89.4 and 100%, respectively. Oropharyngeal and naris specimens were the most reliable samples for MRSA detection. False-negative results were frequent in bronchial aspirates with low (<103 to 106CFU/ml) MRSA counts. False-positive results were mainly due to methicillin-resistant Staphylococcus haemolyticus. The SSMAC tube is a useful, rapid, and inexpensive tool for the early identification of MRSA-colonized patients and, consequently, for the implementation of measures to prevent the spread of MRSA.

Screening for Carriage of Methicillin-Resistant Staphylococcus aureus Shortly After Exposure May Lead to False-Negative Results

2008 ◽  
Vol 29 (8) ◽  
pp. 774-776 ◽  
Author(s):  
John Evison ◽  
Kathrin Mühlemann
Keyword(s):  
Staphylococcus Aureus ◽  
Incubation Period ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
False Negative ◽  
Screening Strategy ◽  
Methicillin Resistant ◽  
Negative Results ◽  
False Negative Results

We evaluated a double screening strategy for carriage of methicillin-resistant Staphylococcus aureus (MRSA) in patients exposed to a newly detected MRSA carrier. If the first screening of the exposed patient yielded negative results, screening was repeated 4 days later. This strategy detected 12 (28%) of the 43 new MRSA carriers identified during the study period. The results suggest that there is an incubation period before MRSA carriage is detectable.

An Outbreak of Methicillin-Resistant Staphylococcus aureus in a Neonatal Intensive Care Unit

2003 ◽  
Vol 24 (5) ◽  
pp. 317-321 ◽  
Author(s):  
Lisa Saiman ◽  
Alicia Cronquist ◽  
Fann Wu ◽  
Juyan Zhou ◽  
David Rubenstein ◽  
...  
Keyword(s):  
Intensive Care Unit ◽  
Staphylococcus Aureus ◽  
Intensive Care ◽  
Neonatal Intensive Care Unit ◽  
Neonatal Intensive Care ◽  
Methicillin Resistant ◽  
Children's Hospital ◽  
Surveillance Cultures ◽  
Children’S Hospital ◽  
Incident Cases

AbstractObjective:To describe the epidemiologic and molecular investigations that successfully contained an outbreak of methicillin-resistant Staphylococcus aureus (MRSA) in a neonatal intensive care unit (NICU).Design:Isolates of MRSA were typed by pulsed-field gel electrophoresis (PFGE) and S. aureus protein A (spa).Setting:A level III-IV, 45-bed NICU located in a children's hospital within a medical center.Patients:Incident cases had MRSA isolated from clinical cultures (eg, blood) or surveillance cultures (ie, anterior nares).Interventions:Infected and colonized infants were placed on contact precautions, cohorted, and treated with mupirocin. Surveillance cultures were performed for healthcare workers (HCWs). Colonized HCWs were treated with topical mupirocin and hexachlorophene showers.Results:From January to March 2001, the outbreak strain of MRSA PFGE clone B, was harbored by 13 infants. Three (1.3%) of 235 HCWs were colonized with MRSA. Two HCWs, who rotated between the adult and the pediatric facility, harbored clone C. One HCW, who exclusively worked in the children's hospital, was colonized with clone B. From January 1999 to November 2000, 22 patients hospitalized in the adult facility were infected or colonized with clone B. Spa typing and PFGE yielded concordant results. PFGE clone B was identified as spa type 16, associated with outbreaks in Brazil and Hungary.Conclusions:A possible route of MRSA transmission was elucidated by molecular typing. MRSA appears to have been transferred from our adult facility to our pediatric facility by a rotating HCW. Spa typing allowed comparison of our institution's MRSA strains with previously characterized outbreak clones.

scholarly journals Evaluation of the Carba NP Test for Rapid Detection of Carbapenemase-Producing Enterobacteriaceae and Pseudomonas aeruginosa

2013 ◽  
Vol 57 (9) ◽  
pp. 4578-4580 ◽  
Author(s):  
Nathalie Tijet ◽  
David Boyd ◽  
Samir N. Patel ◽  
Michael R. Mulvey ◽  
Roberto G. Melano
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Positive Predictive Value ◽  
Negative Predictive Value ◽  
Predictive Value ◽  
Rapid Detection ◽  
False Negative ◽  
Bacterial Extract ◽  
Content Type ◽  
Negative Results ◽  
False Negative Results

ABSTRACTThe Carba NP test was evaluated against a panel of 244 carbapenemase- and non-carbapenemase-producingEnterobacteriaceaeandPseudomonas aeruginosaisolates. We confirmed the 100% specificity and positive predictive value of the test, but the sensitivity and negative predictive value were 72.5% and 69.2%, respectively, and increased to 80% and 77.3%, respectively, using a more concentrated bacterial extract. False-negative results were associated with mucoid strains or linked to enzymes with low carbapenemase activity, particularly OXA-48-like, which has emerged globally in enterobacteria.

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