ASM Microbe

ASM Microbe

Perspective from Edward G. Dudley, PhD
June 02, 2017
2 min read

Lactobacillus isolate in yogurt inhibits multidrug-resistant, gram-negative bacteria

Perspective from Edward G. Dudley, PhD
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NEW ORLEANS — A Lactobacillus isolate found in commercial yogurt inhibited the growth of several multidrug-resistant, gram-negative bacteria, according to study findings presented here.

Researchers from the laboratory of Broderick Eribo, PhD, in the department of biology at Howard University in Washington, D.C., said they discovered a potentially novel L. parafarraginis strain while testing lactic acid bacteria (LAB) isolates from commercial yogurt and cheese.

Image of yogurt
Researchers said a Lactobacillus isolate found in commercial yogurt inhibited the growth of several multidrug-resistant, gram-negative bacteria.

Their analysis indicated that the inhibitory agent may be a bacteriocin — peptides released by bacteria that are active against related bacteria. Bacteriocins have importance primarily in the food industry, according to study researcher and doctoral candidate Rachelle Allen-McFarlane, who said more attention should be paid to them as alternatives to current antibiotics.

Allen-McFarlane said their findings are important to clinicians because of the need to find alternative therapies amid the growing problem of antimicrobial resistance in hospitals, especially among gram-negative bacteria.

She would not identify the brand of yogurt that contained the L. parafarraginis strain, saying it could attract undue attention.

Rachelle Allen-McFarlane
Rachelle Allen-McFarlane

“Many of the procedures that clinicians execute incorporate the use of antibiotics to keep at bay infections,” Allen-McFarlane told Infectious Disease News during ASM Microbe. “Experiments that hold prospects of identifying alternative antimicrobial agents to the currently used antibiotics offer hope to clinicians that retrograde steps in the practice of medicine will not occur.”

According to Allen-McFarlane and colleagues, several studies have shown that Lactobacilli produce antimicrobial activity against gram-positive bacteria, but few have reported activity against gram-negative bacteria.

They discovered the L. parafarraginis strain while testing 68 LAB isolates from commercial yogurt and cheese for antimicrobial activity against Staphylococcus aureus, Listeria monocytogenes and Escherichia coli — standard indicator organisms.

Further testing of the potentially novel strain, which they called L. parafarraginis KU495926, showed that it inhibited 14 multidrug-resistant and extended-spectrum beta-lactamase bacteria from clinical sources, including five E. coli isolates.

“Humanity is presently faced with an upsurge of multidrug-resistant bacteria,” Allen-McFarlane said. “This poses great threat to human security because it could push us back into the pre-antibiotic era when minor infections and injuries could easily result in death.” – by Gerard Gallagher


Allen-McFarlane RS, et al. Lactobacillus parafarraginis KU495926 inhibits multi-drug resistant and extended spectrum beta-lactamase producing gram-negative bacteria. Presented at: ASM Microbe; June 1-5, 2017; New Orleans.

Disclosure: The researchers report no relevant financial disclosures.