Medical Device Link.

FINAL THOUGHTS

The streak-plate procedure is the classic method of isolating individual strains of bacteria from a sample. To perform this procedure, a lab worker spreads bacteria from a sample onto an agar plate in a way that will facilitate rapid growth of colonies. The worker touches the sample (from urine, feces, or swabs) with a sterile loop, and drags the loop in a zigzag pattern across the surface of the plate. He or she then drags a second loop through a portion of the streak pattern and creates another zigzag formation to pick up the original inoculum. The purpose is to spread bacteria from the first pattern into a second distinct pattern. This process is repeated with the goal of moving smaller populations of the bacteria as far apart as possible to help them grow.

The plate-streaking signature of every person in a lab is as distinct as an actual handwriting signature. When streaking is done properly, colonies of bacteria grow and thrive away from competing colonies. For an average clinical sample, plate streaking is repeated three times on different culture media that are conducive to the growth of different species.

The streak-plate procedure is time-consuming and can lead to repetitive stress injury in those performing it. However, while tedious, the method does require great skill. The distance between zigzagging lines and the pressure used to inoculate the media are vitally important variables. Hands-on streaking can present a challenge in maximizing bacteria-colony isolation and standardizing plate inoculation and results. As a result, lab workers often agonize over plates with no growth: Was there no bacteria in the sample, or was there a flaw in plate-streaking procedure?

An automated procedure offers improved consistency in process and streaking patterns. At a time when the microbiology lab faces an ever-increasing labor shortage, medical and laboratory technicians are difficult to recruit. One way to retain these highly trained and valuable resources is to keep them challenged in the lab and engaged with new technologies and expanding workloads. Automating the plate-streaking procedure allows lab managers to optimize the use of critical technical staff and streamline work flow. Automation can also improve lab technician satisfaction by freeing staff from mundane, repetitive tasks that potentially introduce error. These tasks occur at the preanalytic, analytic, and postanalytic phases, and nearly all can now be automated.

Of course, reducing error directly benefits patient outcomes, but it also reduces cost. Some automated systems, such as those that identify antibiotic susceptibility, can avert the prescription of incorrect medications, which is clearly better for the patient as well as the hospital’s bottom line by reducing waste at the pharmacy.

Consistent results and economic savings are two arguments for automating the plate-streaking procedure, but the most important reason is patient care. The growing problem of hospital-acquired infections, coupled with the rising tide of antibiotic resistance, highlights the invaluable role of the microbiology lab in the modern hospital. Much of the clinically actionable information regarding strain, resistance, and antimicrobial selection is provided by the microbiology lab.

Giving these laboratory scientists the best tools available to improve their speed and accuracy is vital. Repeating an inconclusive culture could mean the difference between prescribing the right or wrong antibiotic or leaving patients exposed to someone infected with a resistant organism. These scenarios have real and substantial impact on patient care and outcomes. Speeding the appropriate care to these patients has a dramatic impact on their lives and the cost of care. A serious blood-borne infection can be very costly to treat with funds that may not necessarily be reimbursed to the hospital. Automated plate streaking cannot solve all of these problems, but it represents a piece in the puzzle toward a lasting solution. A clear opportunity exists to improve the healthcare system by updating antiquated systems and automating manual processes.

Sampling and preprocessing microbiology labs’ wide variety of samples for automatic streaking has been a major challenge. Regardless of the product a lab chooses, it is important that the device suit the unique needs of the lab and adapt to a given sample’s phase, shape, and consistency. The instrument should also facilitate the reading of colonies.

The decision to introduce automation to the plate-streaking process needs to be carefully considered, balancing the needs of the hospital with the age of current equipment, volume of the lab, and staffing needs.