Medical microbiology — and by this, I mean “bug
study” as it appears to be conducted by medical practitioners (except
for lab folk) — generally remains a mystery, right up there with
computer billing and the purported thinking of politicians.
With few sometimes-scary exceptions, docs and nurses
are generally content to rely on the reports that come out of the
mysterious laboratory printer. This is most interesting as they receive
much more education in microbiology than they do in blood banking — and
they are all experts in that field (but that is another story).
There are two problems that many of them still fail
to grasp: the first is that bugs grow at their own rate. (I once had an
intern sit in my lab for a half hour; he asked if he could wait for the
blood culture result. I told him, “Sure, have a seat.” He eventually
figured it out.).
The second problem is that there is a reason we do
sensitivities. Not all bugs are equally sensitive or resistant, but we
do provide antibiograms to let docs and nurses know what are the most
likely magic pills (or juices) for what are the “local bugs du jour.”
How many actually use these solutions is another matter (you can lead a
horse to water …).
—Chuck Millstein, MBA, MT(ASCP), CLDir(NCA), Retired
Throat cultures: First, do no harm
It scares me to see so much diversity in the
reporting of throat cultures. A nurse at a busy practitioner's office
called me. She chastised me for not giving her a full throat-culture
report like the one she got from the “other lab.” Our report only stated
“No Group A Streptococcus pyogenes recovered.” I asked her what
she would do if we reported out Haemophilus influenzae or
Staphylococcus aureus or Streptococcus pneumoniae. She said
they would treat it.
Haemophilus influenzae epiglottitis is a
clinical diagnosis substantiated by culture. Other than that
unique syndrome, it does not contribute to pathogenic processes in the
throat.
Arcanobacterium hemolyticum and Group C
Streptococcus can cause severe pharyngitis, and antibiotics may
shorten the course of disease — but they are not known to cause serious
sequelae clearly associated with Group A Streptococcus.
Antimicrobials are given to prevent advancement into more serious
disease, not necessarily to treat self-limiting infections. There is no
scientific evidence that S aureus causes a sore throat. There
is evidence, however, that colonization of the pharynx with S
aureus increases after antibiotic therapy.
Interesting story: I did the microbiology for several
outside locations. One of our urgent-care facilities was sending us
throat cultures on standard transport media. By the time we received
them into our lab, they could be anywhere from eight to 24 hours old.
Around 80% of these cultures grew out S aureus so luxuriously
that it overwhelmed everything else on the plates.
I started to rethink my opinions about the organism,
toying with the idea that there may be a virulent strain epidemic in
that area. After brief detective work, I discovered that the staff was
storing the collected specimens on top of their refrigerator where the
temperature was close to 35^0C! The problem was solved when
they kept them in the refrigerator. Transport media has its
limitations.
Why do you think we have to screen sputum specimens
so stringently for acceptability? Sputum passes through the upper
respiratory tract, which is teaming with bacteria. Almost all bacterial
pneumonias are caused by aspiration of normal pharyngeal (throat) flora
down into the sterile lower respiratory tract. What is normal in
the pharyngeal mucosa (e.g., S pneumoniae, H influenzae,
S aureus, Moraxella catarrhalis) can be deadly in the lower
respiratory tract.
If we do not screen sputum specimens carefully, we
are giving out erroneous information. And if we are not selectively
reporting throat culture results, we are definitely going to contribute
to antibiotic overuse.
—Colleen K.
Gannon, MT(AMT) HEW
the “Nancy Grace” for labs
True dedication
Pat has been a med tech since the early 1950s. Her
first job was at Astra Pharmaceutical in Worcester, MA. She went on to
work at Memorial Hospital and Worcester City Hospital, where she was in
charge of the med-tech training program. In 1976, Pat moved to Falmouth
and has worked at Falmouth Hospital ever since.
Her skills, endurance, expertise, and professionalism
keep her younger co-workers on their toes. She not only works two to
three days a week in a regular part-time position as a generalist, she
is one of the first to volunteer as a substitute for sick and vacation
needs.
We at Falmouth Hospital Laboratory find Pat an
indispensable part of our lab family, if not the key member.
We wish her many more happy lab birthdays to come.
