Department of Pathology

MICROBIOLOGY

The scope of the Clinical Microbiology Service (CMS) under Dr. Preeti Pancholi (director) and Dr. Joan-Miquel Balada-Llasat (associate director) is to provide timely and accurate medically necessary tests to aid in the evaluation, diagnosis and treatment of infectious diseases. CMS encompasses bacteriology, mycobacteriology, mycology, virology, parasitology and molecular microbiology. The specific goals are multifaceted and focus on the following: 1) practice evidence based laboratory medicine; 2) expand rapid technology to detect pathogens to impact optimal patient management; 3) participate in surveillance team efforts to plan and execute epidemiological investigations; 4) participate in antimicrobial restriction and control programs to minimize the spread of antibiotic resistant pathogens. The CMS is a highly complex discipline that plays a pivotal role as essential member of multidisciplinary teams.

The laboratory experienced another productive year. Over 281,123 specimens were received for testing. This represents a 5% increase over the previous year. The most marked test increases were noted in the molecular microbiology area. We launched a new molecular test for the detection of BK virus (previously a send out) from plasma and urine. The HCV and HBV viral load tests were transitioned to FDA-approved tests and detection of respiratory viruses is now performed entirely by molecular testing instead of viral culture. Furthermore, we implemented a rapid PCR test for the detection of toxigenic Clostridium difficile using the GeneXpert™ automated real time PCR. With the implementation of rapid tests and quick communication to the physicians and pharmacists a positive impact was observed in improving not only patient management (patients being treated with more effective therapy) but also to rapidly institute isolation measures.

For many organisms, traditional phenotypic identification can be difficult, laborious and time-consuming. The CMS is currently using 16S rRNA sequencing for Mycobacteriium spp. and other bacteria where it can take days to weeks to get a definitive identification by standard methods. Because Mycobacterium chelonae and M. abcessus differentiation is important for proper antimicrobial therapy and these organisms cannot be differentiated by 16S rRNA sequencing, we validated the hsp65 gene sequencing for their differentiation. The laboratory monitors the presence of Legionella spp. in clinical and water specimens. In March, 2011, the CMS received the qualification to be part of the CDC ELITE Legionella water testing program. The ELITE members are posted on the CDC web site to enable others seeking this service. We are currently the only lab in the state of Ohio to have received this status.

The laboratory uses the rep-PCR system for bacterial strain typing (fingerprinting). One of the projects utilizing this technology consisted of studying KPC-producing K. pneumoniae to identify risk factors and implementation of effective infection control strategies and empiric antimicrobial therapy. The infections caused by these organisms present an increasingly complex challenge for our antimicrobial stewardship program. Furthermore, as part of the CDC study collaboration with infectious disease investigators, more than 800 MRSA strains received from several hospitals in central Ohio were strain typed by rep-PCR. Our studies identified the recent emergence of infections due to ST239-MRSA in the Midwestern U.S, a strain of great public health concern because of its propensity to cause outbreaks The clinical microbiology laboratory is a key member of the multidisciplinary Antimicrobial Stewardship Program. With the increase of bacterial resistance to the current used antimicrobials and limited development of new antimicrobials, it is imperative to re-evaluate “old” antimicrobial agents. Extensive susceptibilities studies with Minocycline and Fosfomycin were undertaken. Fosfomycin was included in the formulary for the treatment of urinary tract infections caused by vancomycin resistant Enterococcus faecalis and E. faecium, extended spectrum beta-lactamase-producing organisms, and carbapenemase-producing organisms. Minocycline was also included in the formulary for the treatment of multidrug resistant Acinetobacter baumannii. The laboratory now routinely supplements susceptibilities to these agents by E-test. Because of an increase in special requests for antimicrobial testing, 2 new Microscan panels were introduced to offer susceptibility testing for Cefazolin and Doripenem.

The clinical microbiology laboratory actively participates in scholarly activities and teaching rounds that involve pathology residents, infectious disease fellows, pharmacists, undergraduates, and MLT and MT students.

This year Dr. Pancholi participated in writing new guidelines for infectious disease testing for the Clinical Laboratory Standard Institution for “Establishing Molecular Testing in Clinical Laboratory Environments”. She was also a keynote speaker for “Evolving Respiratory Viral Testing and its impact on patient management” ASCLS Annual Meeting, Annaheim, CA.