An effective active surveillance method for controlling nosocomial MRSA transmission in a Japanese hospital

Prevalence of Colonization with Multidrug-Resistant Bacteria: Results of a 5-Year Active Surveillance in Patients Attending a Teaching Hospital

Combating antimicrobial resistance (AMR) requires comprehensive efforts, such as screening to identify patients colonized by multidrug-resistant microorganisms (MDROs). The primary purpose of this study was to estimate the AMR pattern of methicillin-resistant Staphylococcus aureus (MRSA) isolated from nasal surveillance swabs and MDROs isolated from pharyngeal and rectal surveillance swabs in patients attending a teaching hospital. Data were sought retrospectively, from 1 January 2017 to 31 December 2021, from the records produced by the hospital microbiology laboratory. Duplicate isolates, defined as additional isolates of the same microorganism with identical antibiograms, were excluded. Among Staphylococcus aureus isolates from nasal swabs, 18.2% were oxacillin-resistant. Among Gram-negative bacteria, 39.8% of Klebsiella pneumoniae and 83.5% of Acinetobacter baumannii isolates were carbapenem-resistant. Resistance to three antibiotic categories was high among Acinetobacter baumannii (85.8%) and Klebsiella pneumoniae (42.4%). The present data highlight a high prevalence of MDRO colonization among patients admitted to the hospital and suggest that screening for MDROs could be an important tool for infection control purposes, especially in geographical areas where limiting the spread of MDROs is crucial. The results also underline the importance of active surveillance, especially for carbapenem-resistant, Gram-negative bacteria in reducing their transmission, especially in high-risk units.

The Active Surveillance of Staphylococcus aureus using Polymerase Chain Reaction-based Identification Method among Hospitalized-patient of Haji Adam Malik General Hospital, Medan, Indonesia

BACKGROUND: Active surveillance of methicillin-resistant Staphylococcus aureus (MRSA) carriers is associated with the lower incidence of bacteremia and lower mortality rates throughout literature; yet, this important step still remains problematic for developing countries, particularly Indonesia. AIM: The study aimed to demonstrate MRSA colonization rate in Haji Adam Malik Hospital, Medan, Indonesia. MATERIALS AND METHODS: The study enrolled 200 mucocutaneous isolates obtained from hospitalized patients during a 1-year period of study (2018). VITEK-2 system in addition to standard bacterial identification, such as gram staining, latex agglutination test, and hemolysis pattern, was performed to select S. aureus colonies in two different laboratories, Microbiology laboratory of Haji Adam Malik General Hospital and Multidisciplinary Laboratory, Faculty of Medicine, Universitas Sumatera Utara, for polymerase chain reaction (PCR) examination. RESULTS: Based on the VITEK-2 system preliminary identification, there were 80 S. aureus colonies which then underwent PCR examination. Through standard PCR assay, there were 32 bacterial isolates contained the mecA gene and it can be determined MRSA colonization rate of the hospital was 16% with consistent results of standard bacterial identification. CONCLUSIONS: Active surveillance of MRSA carriers is mandatory and urged it as a regular program in a hospital setting to decrease MRSA transmission rate.

A Rapid and Quantitative Flow Cytometry Method for the Analysis of Membrane Disruptive Antimicrobial Activity

We describe a microbial flow cytometry method that quantifies within 3 hours antimicrobial peptide (AMP) activity, termed Minimum Membrane Disruptive Concentration (MDC). Increasing peptide concentration positively correlates with the extent of bacterial membrane disruption and the calculated MDC is equivalent to its MBC. The activity of AMPs representing three different membranolytic modes of action could be determined for a range of Gram positive and negative bacteria, including the ESKAPE pathogens, E. coli and MRSA. By using the MDC50 concentration of the parent AMP, the method provides high-throughput, quantitative screening of AMP analogues. A unique feature of the MDC assay is that it directly measures peptide/bacteria interactions and lysed cell numbers rather than bacteria survival as with MIC and MBC assays. With the threat of multi-drug resistant bacteria, this high-throughput MDC assay has the potential to aid in the development of novel antimicrobials that target bacteria with improved efficacy.