4 DISCUSSION
The World Health Organization has suggested that breast milk culture and
sensitivity testing should not be routinely performed and should be
performed if there is any of the following situations: (1) no response
or poor response to the antibiotic within 2 days; (2) the mastitis
recurs; (3) hospital-acquired mastitis; (4) allergic to the usual
therapeutic antibiotic; and (5) in severe or unusual cases. Therefore,
in clinical practice, antibiotic use for acute mastitis has always been
empirical worldwide, and even in developed countries such as
Australia,1,12 Spain13 and the
USA,14,15 as high as 77-97% patients with
breastfeeding mastitis are prescribed wih toral or intravenous
antibiotics without direct evidence of bacterial infection. Indeed, in
China mainland, antibiotic use is usually based on the level of SLCs and
the severity of symptoms and signs, but not on the results of
bacteriological analyses, although the latter has been helpful in
determining the presence of pathogenic bacteria.
A previous study found that higher SLCs were associated with the
existence of potentially pathogenic bacteria.10 Higher
SLCs may indicate a higher chance of infection, which is useful in
certain clinical conditions. For patient who is unwilling to undergo
bacterial cultivation of breast milk or in the most of medical agencies
where bacterial cultivation is not a routine practice, antibiotic use
based on the SLCs seems to be a practical choice. SLC is routinely
obtained in the work-up of patients with acute mastitis in China. If SLC
is above the normal level, antibiotics are often recommended by
attending physicians in the emergency department; otherwise, antibiotics
are not advised. To the best of our knowledge, the study is the first to
explore the value of SLCs for initial antibiotic use in breastfeeding
mastitis.
In our study, the majority of (98.1%) patients with MELCs were
prescribed an initial antibiotic, so we could not assess the necessity
of initial antibiotic use effectively. However, we found a great
difference in patients with MELCs; 5.5% (9/153) versus 100.0% (3/3)
patients with MELCs had a disease progression when the antibiotic was or
not given at their first presentation to the hospital. The result
indicates that initial antibiotic use is still essential for acute
mastitis with MELCs.
Our study also showed that there was a better clinical outcome in
patients with SELCs when antibiotic was given initially. There should be
two possibilities for mastitis: the presence of both inflammation and
infection in the breast, or the presence of only inflammation but no
infection in the breast. However, we could not distinguish these two
situations clearly without the evidence of bacterial cultivation. Even
so, for patients with SELCs, there was an absolute difference of 23.3%
on the rate of treatment failure between patients with antibiotic use
and without antibiotic use, which demonstrated that appropriate
antibiotics should also be recommended for patients with SELCs.
In the current study, the rate of breast abscess was 7.1%, which was
higher than that in the large Australian study which found that 3% of
breastfeeding women with mastitis developed breast
abscess.16 The difference in race and characteristics
of patients in two studied may contribute to the different rate of
breast abscess.
The limitations also should be acknowledged. First and most important,
the present study was a single-institution, observational, retrospective
study, which decreases the external validity of our work. Second, the
level of SLCs in acute mastitis was always elevated, and acute mastitis
patients with normal SLCs in clinical practice were rare; thus, the
present study did not include such patients. Thus, the value of SLCs for
antibiotic use in such patients could not be explored in the study.
Third, in our study, milk cultivation and bacteriological analysis were
not routinely performed, and antibiotics were initially used to targetS. aureus , which was found to be the most pathogenic bacteria in
previous studies.17-20
In this study, we found that there was a better clinical outcome for
patients with SELCs when antibiotic was given compared to when an
antibiotic was not given. In addition, there was a good clinical outcome
for patients with MELCs when antibiotic was given initially. These
results suggest that, in China mainland, SLCs may have a reference value
for antibiotic use in breastfeeding women with acute mastitis, and those
sufferering from acute mastitis with elevated SLCs should be prescribed
with antibiotic their first presentation to hospital. Of course,
large-scaled, randomized controlled trials (RCTs) of higher quality are
still required to confirm our findings.