Medical Microbiology

Johns Hopkins Medicine
Department of Pathology
Division of Medical Microbiology
600 N. Wolfe Street
Meyer B1-193
Baltimore, MD 21287

Lab Phone: 410-955-6510
Office Phone: 410-955-5077
Fax: 410-614-8087

About Us


Medical Microbiology is a tradition at The Johns Hopkins Hospital. William Henry Welch, the father of American Pathology, was the original Johns Hopkins Hospital microbiologist and a pioneer in the application of culture of bacteria for diagnosis of infections. The current division has offered state-of-the-art infectious disease diagnoses and consultative services for the clinical staff and physicians of the hospital since 1969.

In the 1970s, faculty provided expert diagnosis and treatment of fungal infections at a time when fungi were just being recognized as emerging threats to compromised patients. In 1989, the molecular revolution entered our laboratories, with nucleic acid probes and polymerase chain reaction used for rapid, sensitive detection and diagnosis of disease.

Today, with faculty internationally known for research and test development in diverse areas, the division is at the forefront of infectious disease diagnosis, consultation, and patient management. The laboratory is directed by Karen Carroll, M.D.


Expert consultation
Because of the unusually broad patient base here, we have unique experience in developing or adapting specialized testing methods and interpreting complex data. Faculty expertise includes bacteriology analysis, antibiotic susceptibility testing, mycology, virology, tick-borne pathogens, molecular microbiology, mycobacteriology, international microbiology, molecular epidemiology, and parasitology. New testing methods pioneered here include PCR diagnostics, bacterial gene sequencing for identification, and tests for susceptibility of yeasts and viruses to antifungal or antiviral agents in vitro.

Faculty is readily available to advise treating physicians and others on which tests to order and discuss the implications of test results.

Special Capabilities and Services

Our laboratory provides diagnoses for almost 400,000 patient specimens each year. Many of the diagnostic tests we perform -- including some developed here -- are not widely available in other laboratories and institutions. Also, faculty has the expertise to design customized testing, as needed -- applying and adapting cutting-edge technologies to meet special needs.

Timely Results

Turnaround time varies by test from a few hours to several days for particularly complex tests (please call the Customer Service Line for specific turnaround times by test and for information on how to prepare and ship specimens.) Test results can be delivered by phone, fax, e-mail, written report.