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Journal of Clinical Microbiology, May 2009, p. 1605-1606, Vol. 47, No. 5
0095-1137/09/$08.00+0 doi:10.1128/JCM.02337-08
Copyright © 2009, American Society for Microbiology. All Rights Reserved.
First Case Report of Sepsis Due to Rothia aeria in a Neonate
Ayaka Monju,1,2*
Naomasa Shimizu,1
Masahiro Yamamoto,1
Keiko Oda,2
Yutaka Kawamoto,1 and
Kiyofumi Ohkusu3
Departments of Neonatology,1
Pediatrics, Kawasaki Medical School, Okayama, Japan,2
Department of Microbiology, Gifu University Graduate School of Medicine, Gifu, Japan3
Received 5 December 2008/
Returned for modification 22 January 2009/
Accepted 23 February 2009

ABSTRACT
Rothia aeria, a gram-positive coccoid- to rod-shaped bacterium
with irregular morphology, is an extremely rare causative organism
of infections in humans. We report the first case of
R. aeria sepsis clinically manifested in a female neonate soon after
birth.

CASE REPORT
A female neonate, weighing 3,152 g, was born to a 30-year-old
healthy mother, gravida 1, para 1, at full term by spontaneous
vaginal delivery with Apgar scores of 9 and 10 at 1 and 5 min,
respectively. She had no history of intrauterine device use.
Aside from 4 days prior to delivery, when she underwent a decayed
tooth extraction with no following antibiotic treatment, the
pregnancy was uneventful. Routine vaginal cultures at 30 gestational
weeks were not significant. One hour prior to delivery, artificial
rupture of her amniotic membrane released clear amniotic fluid,
and intrapartum monitoring revealed no evidence of fetal distress.
Soon after birth, mild tachypnea, retraction, and grunting were
noticed in the neonate. At 3 h after birth, the neonate was
transferred to our hospital as symptoms worsened. At admission,
we detected moderate restlessness and irritability with mild
cyanosis even under 30% inspired oxygen, a temperature of 37.8°C,
a pulse rate of 150 beats per minute, and a respiratory rate
of 100 breaths per minute. A chest radiograph revealed diffuse
bilateral infiltrates and some pleural effusion in the lung
fields despite the absence of pleocytosis in the cerebrospinal
fluid. Laboratory findings for the peripheral venous blood on
admission are displayed in Table
1. Following a sepsis work-up,
the neonate was treated with respiratory treatment of nasal
directional positive airway pressure with 30% inspired oxygen
and with combination chemotherapy of ampicillin (200 mg/kg/day)
and cefotaxime (150 mg/kg/day). At 2 days after birth, the respiratory
symptoms decreased dramatically, and the inspired oxygen concentration
was weaned to room air despite the persistent presence of mild
emphysematous findings in the lung fields on a chest radiograph.
Blood work results thereafter regarding the inflammation are
displayed in Table
2. The venous blood specimen collected in
a Bactec Peds Plus/F bottle (Becton Dickinson Diagnostic Instrument
Systems) at admission was registered positive for a gram-positive
bacillus after 4 days of incubation in an automated blood culture
system (Bactec 9240; BD Diagnostics Systems). The isolate was
eventually identified as
Rothia aeria at 10 days after birth.
Each culture taken from the throat, body surface, rectum, and
cerebrospinal fluid was negative. The placenta was not available
for pathological and bacteriological analyses, as it was discarded
soon after delivery. At 13 days after birth, the neonate was
discharged in good health after an 11-day course of intensive
antibiotic chemotherapy.
Discussion.
To the best of our knowledge, this is the first report of a
Rothia aeria culture in human blood.
R. aeria, isolated for
the first time from the air and condensation water sampled in
the Russian space station Mir in 1997, is an aerobic, gram-positive,
coccoid, coccobacillary or filamentous bacterium (
6).
Common biochemical characteristics and antibiotic sensitivities of R. aeria are displayed in Tables 3 and 4, respectively. The antimicrobial susceptibility of the organism was assessed using the disk diffusion method. Because there are no Clinical and Laboratory Standards Institute (CLSI) criteria for Rothia spp., categorical interpretations (susceptible, intermediate, or resistant) for disk diffusion tests were the CLSI interpretative criteria for staphylococci (3).
In Similarity to
Actinomyces species,
Rothia species are considered
to be normal inhabitants of the oral cavities of humans (
1)
and rarely cause serious infections (e.g., endocarditis [
2],
sepsis [
11], dialysis-related peritonitis [
9], endophthalmitis
[
8], arthritis [
7], and pneumonia [
10]). A recent report documented
a case of intrauterine fetal death at full term with a possible
association to
R. dentocariosa (
5). However, we were unable
to find any reported case of infections aside from sepsis due
to
R. aeria, although there was a report of
R. aeria colonization
on the tongue of a healthy adult (
4).
In the present case, the identification of the organism was confirmed by sequencing the 16S rRNA gene, and DNA sequences were compared to published sequences retrieved from the GenBank database (National Center for Biotechnology Information, National Library of Medicine, Bethesda, MD).
Given the early onset of symptoms after birth and the absence of the organism in cultures other than blood upon admission, we suspect that direct hematogenous placental infection through the maternal blood supply or infectious placental contiguity from the uterine wall lesion was the more likely route of bacterial entry, as opposed to birth canal exposure at delivery or antecedent amniotic fluid infection. Actinomycetales species, part of the normal vaginal flora, have been isolated with increasing frequency from females with intrauterine device-related pelvic infections, but given the mother's good health and the lack of intrauterine device use, it is unlikely that a preceding maternal uterine wall infectious lesion was present. The most likely explanation may be that the organism originated in the socket of the decayed tooth extracted 4 days prior to delivery and then traveled through the maternal bloodstream to cause placental infection and neonatal sepsis soon after birth. We were unable to validate the origin of the organism, as the mother did not agree to submit an additional vaginal or oral swab for cultures after the sepsis diagnosis was confirmed.

FOOTNOTES
* Corresponding author. Mailing address: Department of Pediatrics, Kawasaki Medical School, Matsushima 577, Kurashiki 701-0192, Japan. Phone: 86-462-1111. Fax: 86-464-1067. E-mail:
a.monju{at}med.kawasaki-m.ac.jp 
Published ahead of print on 4 March 2009. 

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Journal of Clinical Microbiology, May 2009, p. 1605-1606, Vol. 47, No. 5
0095-1137/09/$08.00+0 doi:10.1128/JCM.02337-08
Copyright © 2009, American Society for Microbiology. All Rights Reserved.