MALDI-TOF (Matrix-Assisted Laser Desorption / Ionization Time of Flight) mass spectrometry - An Innovation for rapid information on bacteria, fungus & mycobacteria with direct benefits on the patient outcome

The MALDI Biotyper System identifies microorganisms using MALDI-TOF (Matrix-Assisted Laser Desorption / Ionization Time of Flight) mass spectrometry to determine a unique proteomic Mass fingerprint of an organism

Principle
• Matrix crystallizes on drying & the sample gets entrapped within the matrix also co-crystallizes.
• The sample within the matrix is ionized in an automated mode with a laser beam generating singly protonated ions from analytes in the sample.
• The protonated ions are then accelerated at a fixed potential, where these separate from each other on the basis of their mass-to charge ratio (m/z).
• The charged analytes are then detected and measured using time of flight (TOF) mass analyzers.
• The m/z ratio of an ion is measured by determining the time required for it to travel the length of the flight tube.
• Based on the TOF information, a characteristic spectrum called peptide mass fingerprint (PMF) is generated for the sample.
• Identification of microbes by MALDI-TOF MS is done by either comparing the PMF of unknown organism with the PMFs contained in the database, or by matching the masses of biomarkers of unknown organism with the proteome database.

Advantages
The pace of diagnostic processes in clinical microbiology laboratories has largely been unchanged for almost 100 years, as availability of diagnostic results essentially depended on the growth of bacteria. Using traditional approaches, it takes at least 24 hours for obtaining growth from clinical specimens and an additional 24 hours for down-stream isolate characterization, as a consequence - therapeutic decisions are generally made empirically until the availability of species identification and resistance patterns.
Techniques providing rapid information on bacterial pathogens and their antimicrobial susceptibility are of key importance for the management of infectious diseases patients. The MALDI Biotyper System identifies microorganisms using MALDI-TOF (Matrix-Assisted Laser Desorption / Ionization Time of Flight) mass spectrometry to deter¬mine a unique proteomic Mass fingerprint of an organism. The introduction of MALDI-TOF into routine diagnostics at Cancer Institute (WIA) led to a significant acceleration of highly specific species identification and we regard this as a major advance in the field of clinical microbiology. MALDI-TOF has considerably reduced the TAT, therefore the slowness of diagnostic procedures prolonging empiric antibiotic therapies are avoided.
Currently, using traditional approaches, it usually takes at least 48 hours for identification and susceptibility testing of bacterial pathogens. Over the years, several new technologies have entered clinical microbiology laboratories, accelerated phenotypic methods, molecular techniques, MALDI -TOF and next generation sequencing etc. MALDI-TOF mass spectrometry fingerprinting has now been widely adopted by clinical microbiology laboratories for rapid identification of cultured microorganisms. Compared to other conventional (e.g. biochemical) identification workflows, turnaround times are typically reduced by at least one working day up to several days for slower growing species or isolates that require complex tests for definite identification. Highest impact on turnaround times and prescription policies is expected for rapid identification from positive blood culture bottles.
Turnaround time - Within half an hour of Growth & Blood culture: Within half an hour of positivity. While MALDI-TOF fingerprinting had originally been introduced and approved for the identification of solid media cultures, it has readily been adopted for liquid enrichment cultures, reduced turnaround times by at least one working day. MALDI -TOF technique is thus suitable to inform clinicians within the critical phase of sepsis, when laboratory reports are known to have highest impact on treatment decisions.
When made available for routine testing, these assays could add to the armamentarium of rapid susceptibility tests needed to reduce time to optimal antimicrobial therapy. With Cancer Institute starting the innovative MALDI TOF Technology for its patients – wee become the 1st Charitable Non-Profit Institution in the State to have this – it makes us proud & we understand that Novel Techniques like this would impact on Antimicrobial Stewardship Program as well.

4 levels of documents introduced as part of Quality Management System and being implemented and controlled are:
1. Quality Assurance Manual.
2. Laboratory Safety manual.
3. Standard operating procedures and Policies for each test.
4. Work instructions.

1. Internal quality control
2. External quality assurance
3. Pre – analytic phase
4. Test standardization
5. Post – analytic phase management & organization.

*Corrective & preventive are taken promptly to address any deviations.

The Department initiated stringent measures during the pandemic since Mar 2020, Measures were taken to handle the suspected and confirmed COVID cases who visited the Institute. COVID-19 infection spreads through respiratory droplets, direct contact & can be air borne. All staff in patient care areas including the housekeeping services are at risk of infection while handling infected patients.
hence the following guidelines for prevention & control of COVID-19 were strictly adhered.

To ensure prevention of COVID infection, the team monitors I/C practices to ensure staff compliance.
Strict implementation of the following are still monitored:

1. Attenders were restricted to 1 per patient by the security staff
2. Wearing of mask, carrying minimal baggage & hand sanitization was made mandatory at the entrance
3. People were scanned through a Thermal scanner & guided to triaging area
4. Social distancing was ensured
5. Biomedical waste disposal and other general infection control measures were monitored
6. Monitoring of OPD, surface cleaning of the chair/ stool/ couches/ tables and other materials after each patient is examined using a checklist was strictly followed
7. Strict monitoring & implementation of the safety measures in the wards was done by Matrons
8. Hand sanitizers were placed in strategic places in both the campuses
9. Bilingual signage in English & Tamil were displayed

1. Ensuring triage, early recognition, and isolating patients with suspected COVID-19.

2. Applying standard precautions & implementing additional precautions like droplet, contact and airborne precautions.

3. Implementing environmental control, engineering control & administrative controls.

• The support staff engaged in cleaning and disinfection will also wear full complement of PPE.
• Spatial separation of at least 1 meter (3 feet) from one bed to next.
• The access to isolation ward should be through dedicated way.
• Ensure that appropriate hand washing facilities and hand-hygiene supplies are available. Stock the sink area with suitable supplies for hand washing, and with alcohol-based hand rub, near the point of care and the room door.
• Visitors to the isolation ward should be disallowed.