microbiology – Page 37

It’s That Time of Year Again

It’s a few days after a major holiday (Memorial Day in the United States), and clinical microbiologists knows what that means. It’s foodborne illness season! According to the CDC, Norovirus and Salmonella are the biggest culprits, but several organisms can be implicated.

If your lab doesn’t recover Salmonella, Campylobacter, or E. coli O157:H7 often, consider brushing up on the identifying characteristics of these organisms. (Do you know which one doesn’t ferment sorbitol?) It’s also helpful to keep the patient history (in particular, their travel history) in mind when reading enteric cultures or performing a microscopic ova and parasite examination. Also, now is a good time to be sure your reporting procedures (including local public health contact information) are up to date.

Check out the CDC’s website for more information on foodborne outbreaks, including how many people are affected.

–Kelly Swails, MT(ASCP), is a laboratory professional, recovering microbiologist, and web editor for Lab Medicine.

Your Microbiome and Your Health

The fine folks at Scientific American recently published a fascinating blog post about the diversity of one’s fecal bacteria. While it’s long been thought gut microbiomes can vary widely from day to day within the same person, the advent of direct-to-consumer microbiome testing has uncovered that variety can exist within the same specimen.

What? You’ve never heard of personal microbiome testing? Think of it as 23andMe for feces. Ubiome and American Gut provide this service for folks who aren’t squeamish about collecting their own stool swabs.

From the laboratory professional perspective, what do you think about this type of direct-to-consumer testing? Do you think testing a patient’s microbiome has a future in diagnostic or preventative medicine?

–Kelly Swails, MT(ASCP), is a laboratory professional, recovering microbiologist, and web editor for Lab Medicine.

Antiobiotic Resistance Worldwide

The World Health Organization assessed worldwide antibacterial resistance and recently published their findings. The report notes that a post-antibiotic era isn’t a dystopian fantasy but, in fact, a real possibility in the 21^st century. Dire? Yes, but if you’ve been following the news, unsurprising.

The press release is here.

You can download or order the report here.

You can read a summary of the report here.

Lab Week Fun

Since it’s National Medical Laboratory Professionals Week–aka Lab Week–we’d like to start off the week with a poll.

Happy Lab Week, everyone!

Edited 4/25/14 to add: Thanks for playing, everyone! The correct answer–which over 88 percent of you knew–is Saccharomyces cerevisiae.

Photo courtesy of Wikimedia Commons

Haemophilus influenzae Infections in Pregnant Women

The Journal of the American Medical Association recently published a paper about the association of invasive Haemophilus influenzae infections in pregnant women and fetal outcomes. The researchers studied British women who had an invasive H. influenzae infection (defined as recovery of said organism from a normally sterile site). The researchers concluded that pregnant women had a greater risk of invasive infection than non-pregnant women, and these infections resulted in poor pregnancy outcomes.
H. influenzae is a fastidious organism that grows on chocolate agar. Normally associated with respiratory infections, if the organism is an encapsulated strain, it can spread to other parts of the body and cause meningitis, septicemia, pericarditis, and even urinary tract infections.
In terms of identification, H. influenzae are small, gram-negative coccobacilli on microscopic examination. The opaque colonies appear grayish on chocolate agar. Because it requires X and V factors to grow, the organism will appear on blood agar only in the presence of an organism that hemolyzes the blood (like Staphylococcus aureus). In addition to the X and V requirements, H. influenzae ferments glucose and is catalase positive.

Want to learn more? The CDC has great information on this organism.

–Kelly Swails, MT(ASCP), is a laboratory professional, recovering microbiologist, and web editor for Lab Medicine.

Antibacterial Resistance in Pediatric Patients

A recent paper in the Journal of the Pediatric Infectious Diseases Society discusses the rising rates of antibacterial resistance in pediatric patients. It’s an alarming (but not surprising) paper that serves as yet another call to action. Modern medicine is in jeopardy; my hope is that it’s not to late to stop the oncoming catastrophe.

As always, Maryn McKenna over at Superbug has an excellent write-up.

If you’d like to read the paper, it’s here.

Kelly Swails, MT(ASCP), is a laboratory professional, recovering microbiologist, and web editor for Lab Medicine.

Listeria monocytogenes

The FDA is currently reporting an outbreak of Listeria monocytogenes in some Hispanic-style cheeses. While Listeria isn’t listed in the top five pathogens that cause food poisoning, it’s number four on the list of foodborne pathogens that cause death. It also causes meningitis, encephalitis, and septicemia; in pregnant women, it can cross the placenta and cause abortion, stillbirth, or premature birth. Perhaps now would be a good time for a refresher course in this bacterium.

Listeria grows on blood agar; this growth can be enhanced by cold enrichment. Selective enrichment–inhibiting other organisms while bolstering the growth of Listeria–is recommended if the specimen is food or environmental in nature. Other characteristics include:

Short gram-positive rods
motile
Beta-hemolytic
Smooth, light gray, 1-2 mm colonies after 24-48 hours of incubation at 37 degrees C
Will grow at 4 degrees C
facilitative anaerobe
catalase positive
oxidase negative

Listeria can be hard to identify, not because it’s fastidious, but because it can be confused with organisms such as Group B Streptococcus, Erysipelothrix, and corynebacterium. Don’t let that happen to you!

Kelly Swails, MT(ASCP), is a laboratory professional, recovering microbiologist, and web editor for Lab Medicine.

Gut Flora and Chron’s Disease

I’m fascinated by the connection between gut flora and overall health. I just stumbled onto this article that discusses the connection between gut flora and Chron’s Disease. It’s based on this paper published in Cell. Recent articles about antibiotic’s role in obesity and papers on gut flora’s influence on the immune system keep raising the issue: how much do common organisms like E. coli, Clostridium perfringes, and Bacteroides fragilis affect us? How can we use them to diagnose, prevent, or cure disease? I’ll be keeping my eye on future research.

–Kelly Swails, MT(ASCP), is a laboratory professional, recovering microbiologist, and web editor for Lab Medicine.

Antibiotic Stewardship

The draft of the federal budget released Tuesday allocates $30 million dollars in CDC funding in order to combat antibiotic resistance. Obviously the 2015 budget isn’t finalized, but even so, it’s encouraging that the Department of Health and Human Services recognizes the need for antibiotic stewardship.

What is antibiotic stewardship, you ask? Basically, it’s a program within a healthcare community that dictates the best practices for prescribing antibiotics. Such programs would be tailored for each setting based on population demographics and antibiograms. Perhaps a program would prohibit prescribing, say, ciprofloxacin for urinary tract infections because a rise in the percentage of strains of E. coli resistant to fluoroquinolones has been noted. Maybe the program would discourage prescribing more than two antibiotics at once to a patient, or suggest antibiotics other than vancomycin (such as levoquin) when treating MRSA.

Creating a stewardship program requires input from several departments (Infectious Disease, Pharmacy, Epidemiology, and the Microbiology Laboratory) as well as acceptance by the clinician population at large. In my experience, this has been the limiting factor. Physicians don’t like being told what they can and can’t do for their patients or the insinuation that they might lack the proper knowledge about antimicrobials and microbiology to provide good patient care. This is a hurdle that hospitals will have to overcome in order to make stewardship programs a success. (Mentioning that such programs can save money and shorten hospital stays could help tip the scales.)

If you’d like to institute a stewardship program at your institution, here are a few links to get you started:

CDC’s Vital Signs about prescribing practices
Antibiotic management guidelines at John Hopkins
Professional practice resources from the Association for Professionals in Infection Control and Epidemiology
The ever-insightful Maryn McKenna over at Superbug discusses the topic at length

Does your institution have an antibiotic stewardship program? If so, what steps did you have to take in order to implement it?

–Kelly Swails, MT(ASCP), is a laboratory professional, recovering microbiologist, and web editor for Lab Medicine.

Vinegar to the Rescue

Can a common pantry staple kill bacteria? Possibly, according a paper recently published in mBio. Researchers mixed acetic acid–the main ingredient in white vinegar–with suspensions of bacterial cultures and found that a exposure times as little as 20 minutes reduced the viable bacterial population by 7¹⁰. The researchers then performed the same experiment, this time swapping out hydrochloric acid for the vinegar; they noted no bactericidal effect. Mycobacterium tuberculosis required a longer kill time (30 minutes vs. 20 minutes) to reach a 8¹⁰reduction in population.

These results suggest that vinegar could be used as a cheap-yet-effective disinfectant in resource-poor laboratory settings.