Matthew M. Brigmon M.D.

Posted June 24th 2020

Early trends for SARS-CoV-2 infection in central and north Texas and impact on other circulating respiratory viruses.

Manohar B. Mutnal, Ph.D.

Manohar B. Mutnal, Ph.D.

Mutnal, M. B., A. C. Arroliga, K. Walker, A. Mohammad, M. M. Brigmon, R. M. Beaver, J. K. Midturi and A. Rao (2020). “Early trends for SARS-CoV-2 infection in central and north Texas and impact on other circulating respiratory viruses.” J Med Virol May 15;10.1002/jmv.26010. [Epub ahead of print].

Full text of this article.

Rapid diagnosis and isolation are key to containing the quick spread of a pandemic agent like severe acute respiratory syndrome-related coronavirus 2 (SARS-CoV-2), which has spread globally since its initial outbreak in Wuhan province in China. SARS-CoV-2 is novel and the effect on typically prevalent seasonal viruses is just becoming apparent. We present our initial data on the prevalence of respiratory viruses in the month of March 2020. This is a retrospective cohort study post launching of SARS-CoV-2 testing at Baylor Scott and White Hospital (BSWH), Temple, Texas. Testing for SARS-CoV-2 was performed by real-time reverse transcription polymerase chain reaction assay and results were shared with State public health officials for immediate interventions. More than 3500 tests were performed during the first 2 weeks of testing for SARS-CoV-2 and identified 168 (4.7%) positive patients. Sixty-two (3.2%) of the 1912 ambulatory patients and 106 (6.3%) of the 1659 emergency department/inpatients tested were positive. The highest rate of infection (6.9%) was seen in patients aged 25 to 34 years, while the lowest rate of infection was seen among patients aged <25 years old (2%). County-specific patient demographic information was shared with respective public health departments for epidemiological interventions. Incidentally, this study showed that there was a significant decrease in the occurrence of seasonal respiratory virus infections, perhaps due to increased epidemiological awareness about SARS-CoV-2 among the general public, as well as the social distancing measures implemented in response to SARS-CoV-2. Data extracted for BSWH from the Centers for Disease Control and Prevention's National Respiratory and Enteric Virus Surveillance System site revealed that Influenza incidence was 8.7% in March 2020, compared with 25% in March 2019. This study was intended to provide an initial experience of dealing with a pandemic and the role of laboratories in crisis management. This study provided SARS-CoV-2 testing data from ambulatory and inpatient population. Epidemiological interventions depend on timely availability of accurate diagnostic tests and throughput capacity of such systems during large outbreaks like SARS-CoV-2.


Posted May 15th 2020

Impact of Reappraisal of Fluoroquinolone Minimum Inhibitory Concentration Susceptibility Breakpoints in Gram-Negative Bloodstream Isolates.

Matthew M. Brigmon, M.D.

Matthew M. Brigmon, M.D.

Shealy, S. C., M. M. Brigmon, J. A. Justo, P. B. Bookstaver, J. Kohn and M. N. Al-Hasan (2020). “Impact of Reappraisal of Fluoroquinolone Minimum Inhibitory Concentration Susceptibility Breakpoints in Gram-Negative Bloodstream Isolates.” Antibiotics (Basel) 9(4).

Full text of this article.

The Clinical Laboratory Standards Institute lowered the fluoroquinolone minimum inhibitory concentration (MIC) susceptibility breakpoints for Enterobacteriaceae and glucose non-fermenting Gram-negative bacilli in January 2019. This retrospective cohort study describes the impact of this reappraisal on ciprofloxacin susceptibility overall and in patients with risk factors for antimicrobial resistance. Gram-negative bloodstream isolates collected from hospitalized adults at Prisma Health-Midlands hospitals in South Carolina, USA, from January 2010 to December 2014 were included. Matched pairs mean difference (MD) with 95% confidence intervals (CI) were calculated to examine the change in ciprofloxacin susceptibility after MIC breakpoint reappraisal. Susceptibility of Enterobacteriaceae to ciprofloxacin declined by 5.2% (95% CI: -6.6, -3.8; p < 0.001) after reappraisal. The largest impact was demonstrated among Pseudomonas aeruginosa bloodstream isolates (MD -7.8, 95% CI: -14.6, -1.1; p = 0.02) despite more conservative revision in ciprofloxacin MIC breakpoints. Among antimicrobial resistance risk factors, fluoroquinolone exposure within the previous 90 days was associated with the largest change in ciprofloxacin susceptibility (MD -9.3, 95% CI: -16.1, -2.6; p = 0.007). Reappraisal of fluoroquinolone MIC breakpoints has a variable impact on the susceptibility of bloodstream isolates by microbiology and patient population. Healthcare systems should be vigilant to systematically adopt this updated recommendation in order to optimize antimicrobial therapy in patients with bloodstream and other serious infections.