scholarly journals Comparison of an Automated Plate Assessment System (APAS Independence) and Artificial Intelligence (AI) to Manual Plate Reading of Methicillin-resistant and Methicillin-susceptible Staphylococcus aureus Chromagar Surveillance Cultures

Author(s):  
Natalie Gammel ◽  
Tracy L Ross ◽  
Shawna Lewis ◽  
Melissa Olson ◽  
Susan Henciak ◽  
...  

Background: The Automated Plate Assessment System (APAS Independence) [Clever Culture System, Bäch, Switzerland] is an automated imaging station linked with interpretive software that detects target colonies of interest on chromogenic media and sorts samples as negative or presumptive positive. We evaluated the accuracy of the APAS to triage methicillin-resistant Staphylococcus aureus (MRSA) and S. aureus ) cultures using chromogenic media compared to human interpretation. Methods: Patient samples collected from the nares on Eswabs were plated to BD BBL™ CHROMagar™ MRSA II and BD BBL CHROMagar Staph aureus and allowed to incubate for 20-24 h at 37°C in non-CO2. Mauve colonies are suggestive of S. aureus and were confirmed with latex agglutination. Following incubation, samples were first interrogated by APAS before being read by a trained technologist blinded to the APAS interpretation. The triaging by both APAS and the technologists were compared for accuracy. Any discordant results required further analysis by a third reader. Results: Over a five-month period, 5,913 CHROMagar MRSA cultures were evaluated. Of those, 236 were read as concordantly positive, 5,525 were read as concordantly negative, and 152 required discordant analysis. Positive and negative percent agreements (PPA, NPA) were 100% and 97.3%, respectively. The APAS detected 5 positive cultures that were missed by manual reading, and determined to be true positives. In a separate analysis, 744 CHROMagar Staph aureus plates were read in parallel. Of these, 133 were concordantly positive, 585 were concordantly negative, and 26 required discordant analysis. PPA and NPA were 95.7% and 96.7%, respectively. Conclusion: This study confirmed the high sensitivity of digital image analysis by the APAS Independence such that negative cultures can be reliably reported without technologist intervention (NPV 100% for CHROMagar MRSA and 99.0% for CHROMagar Staph aureus). Triaging using the APAS Independence may provide great efficiencies in a laboratory with high throughput of MRSA and S. aureus surveillance cultures.

2003 ◽  
Vol 24 (5) ◽  
pp. 317-321 ◽  
Author(s):  
Lisa Saiman ◽  
Alicia Cronquist ◽  
Fann Wu ◽  
Juyan Zhou ◽  
David Rubenstein ◽  
...  

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.


2020 ◽  
Vol 27 (07) ◽  
pp. 1363-1370
Author(s):  
Aneela Khawaja ◽  
Iffat Javed ◽  
Sohaila Mushtaq ◽  
Saeed Anwar ◽  
Faiqa Arshad ◽  
...  

Antimicrobial resistance (AMR) is a devastating question that is threatening the health globally. The extensive and indiscriminative use of antibiotics has evolved a notorious resistance in Staphylococcus aureus.  This resistance developed through possession of mecA gene, which codes for modified penicillin binding protein (PBP2a) and the emergent strain being labeled “methicillin resistant Staphylococcus aureus”. Conventional phenotypic techniques for detection of MRSA rely on standardization of cultural characteristics. The drawbacks of diagnostic error to report MRSA include: poor prognosis, expensive treatment, dissemination of multi-drug resistant strains and even treatment failure. Latex agglutination method can be adopted as a more accurate and quick strategy for rapid detection of methicillin resistance. Objectives: To compare detection of mecA gene in methicillin resistant isolates of Staphylococcus aureus by latex agglutination and PCR; by assessing the sensitivity and specificity of both methods. Study Design: Descriptive Cross-Sectional study. Setting: Pathology Department, Post Graduate Medical Institute, Lahore. Period: From January 2015 to December 2015; according to standard operating procedures at Microbiology laboratory. Material & Methods: A total 713 consecutive, non-duplicate isolates of Staphylococcus aureus were processed. Methicillin resistance was determined using cefoxitin (30mg) by Kirby-Bauer method using CLSI guideline (2016), latex agglutination method; and PCR for mecA gene. Results: The results showed that out of 713 Staphylococcus aureus isolates, 92 (12.90%) isolates were resistant to cefoxitin and were labelled as MRSA. majority MRSA isolates recovered from pus (44.57%) and wound swab (20.65%), followed by blood (13.04%), fluid (8.70%), CSF (4.35%), CVP (3.26%), HVS (3.26%) and tracheal secretion (2.17%). By latex agglutination method, 87 (94.50%) were positive for PBP2a; while on PCR mecA gene was detected only in 82 (89.10%) MRSA isolates. When assessed with PCR (gold standard) the sensitivity and diagnostic accuracy of latex agglutination was 100% and 94.57%, respectively. Conclusion: Latex agglutination test can be employed as rapid and reliable diagnostic technique in MRSA isolates for mecA gene detection, where resources for molecular methods are inadequate. This can effectually lessen the misdiagnosis of resistant strains, and over/ ill-use of antibiotics.


2020 ◽  
Vol 8 (A) ◽  
pp. 297-302
Author(s):  
Blerta Kika ◽  
Erjona Abazaj ◽  
Oltiana Petri ◽  
Andi Koraqi

AIM: The aim of this study was to evaluate the prevalence of Staphylococcus aureus and methicillin-resistant S. aureus (MRSA) in clinical specimens hospitalized to “Mother Theresa” Hospital Center for 2 years. METHODS: We isolated and identified S. aureus on 356 clinical specimens using standard tests. Furthermore, for further accurate microbial identification, we have to use the VITEK® 2 system. The samples were tested to detect the presence of MRSA by a slide latex agglutination kit for the rapid detection of PBP2. RESULTS: The overall prevalence of S. aureus in patients was 34.2%. The prevalence of MRSA was 20.5% of cases. Of the MRSA isolates identified in this study, 28% were susceptible to antibiotics, 24% demonstrated intermediate resistance, and 48% were multi-drug resistant with resistance to nineteen antibiotics involved in the examination. In addition, seven of the 25 MRSA cases showed 100% resistance to norfloxacin, imipenem, meropenem, levofloxacin, etc. CONCLUSIONS: The rate of S. aureus in hospitalized patients on this study was 34.2% and the MRSA 20.5%. These results indicated that this type of infection is a significant concern for health services and patients included. A screening of all hospitalized cases can lead to reduce the incidence of this infection in the hospital environment.


2007 ◽  
Vol 28 (7) ◽  
pp. 877-879 ◽  
Author(s):  
Marc-Oliver Wright ◽  
Jon P. Furuno ◽  
Richard A. Venezia ◽  
Jennifer K. Johnson ◽  
Harold C. Standiford ◽  
...  

We assessed methicillin-resistantStaphylococcus aureus(MRSA) infection and colonization in hospitalized prisoners. Of 434 admission surveillance cultures, 58 (13%) were positive for MRSA. The sensitivity of admission surveillance cultures of samples from the anterior nares was 72% and increased to 84% when the calculation included cultures of wound samples. Hospitalized prisoners are at high risk for MRSA infection and colonization, and surveillance should include cultures of nares and wound samples.


2020 ◽  
Vol 6 (2) ◽  
pp. 128-133
Author(s):  
Asih Rahayu ◽  
Chylen Setiyo Rini ◽  
Yos Adi Prakoso ◽  
Bagus Uda Palgunadi ◽  
Muhammad Aris Munandar

Background and Aim: The massive utilization of antibiotics has increased resistant genes produced by bacteria. Many bacteria, including Methicillin-resistant Staphylococcus aureus (MRSA), have become resistant against ampicillin (AMP). The combination of an herbal extract with AMP is expected to generate synergistic effects and may restore the susceptibility of MRSA against AMP. This study aimed to analyze the potency of Sauropus androgynous extract (SAE) as a single extract and combination with AMP against MRSA. Materials and Methods: Sauropus androgynous was extracted using 60% ethanol. SAE biochemical compounds were analyzed qualitatively and quantitatively. SAE, AMP, and SAE+AMP were tested against MRSA isolates to determine the minimum inhibitory concentration and fractional inhibitory concentration. The inhibition of penicillin-binding proteins 2a (PBP2a) was analyzed using a latex agglutination test. Further, the disruptive membrane effects of SAE, AMP, and SAE+AMP were analyzed using a scanning electron microscope. The analysis of data was conducted using SPSS version 16 with p=0.01. Results: SAE contained bioactive compounds such as phenolics and flavonoids. Further, 2 mg/mL of SAE could be used as the potential concentration against MRSA isolates in vitro. In addition, the utilization of SAE+AMP generated synergistic effects, restored the susceptibility of isolates against AMP, decreased the synthesis of PBP2a by the MRSA, and induced ultrastructural changes in the bacterial membrane. Conclusion: This study indicated that the utilization of SAE potentially inhibits the growth of MRSA through decreasing of PBP2a expression, disruption of the MRSA membrane, while the combination of SAE+AMP showed synergistic effects against MRSA.


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