Legionellosis
in Children
with Leukemia
in
Relapse
Anthony
L. Kovatch,
MD,
David
S. Jardine,
MD, John
N. Dowling,
MD,
Robert
B.
Yee,
PhD,
and A. William
Pasculle,
ScD
From the Division of Infectious Diseases, Department of Pediatrics, Children’s Hospital of Pittsburgh; Departments of Medicine and Pathology, Presbyterian University Hospital and School of Medicine; and Graduate School of Public Health,
University of Pittsburgh, Pittsburgh
ABSTRACT. Two children with legionellosis
complicat-ing a relapse of acute lymphoblastic leukemia are
re-ported. A 5-year-old boy with pneumonia had Legionella pneumophila cultured from a tracheal aspirate following a rapid deterioration in his respiratory status and intu-bation. This child had severe and irreversible granulocy-topenia and died in spite of therapy with erythromycin
and rifampin added five days later. Combination
anti-microbial therapy is suggested for immunosuppressed children with legionellosis if resolution of neutropenia is
not readily anticipated. Culture of Legionelki sp from
respiratory tract secretions or sputum, as reported for the
first time in the pediatric literature, should be attempted
in all children in whom this infection is suspected. A
13-year-old boy with pneumonia recovered in spite of
ther-apy with antimicrobial agents not proven to be effective
against the legionellae. Clinical improvement coincided
with increase in absolute granulocyte count. A retrospec-tive diagnosis was made when seroconversion to Legion-ella micdadei (<1:16 to 1:1,024) was determined during a
survey of unselected sera from 255 hospitalized children.
This is the first documented case of Pittsburgh
pneu-monia described in a child. Pediatrics 1984;73:811-815; Legionellosis, Legionella pneumophila, Legionella mic-dadei, leukemia.
There is increasing evidence that organisms of the genus Legionella infect children. Cases of Le-gionella pneumophila pneumonia (Legionnaires’
disease) have been documented either by serologic methods or by direct fluorescent antibody staining of respiratory secretions in both healthy’ and immunocompromised2 children, including infants.3 Fatal nosocomial disease in a child has been
re-Received for publication April 15, 1983; accepted July 8, 1983.
Reprint requests to (A.L.K.) Allegheny General Hospital, 320 E
North Aye, Pittsburgh, PA 15212.
PEDIATRICS (ISSN 0031 4005). Copyright © 1984 by the
American Academy of Pediatrics.
ported.4 Although not previously reported,
legionel-bosis due to Legionella sp other than pneumophila
almost certainly also occur in children.
Immunosuppression is known to be a risk factor for the acquisition of Legionnaires’ disease in adults5 and the same may be true for children. We report two cases of legionelbosis occurring in chil-dren with acute leukemia in relapse. In one case, the diagnosis was promptly confirmed when L pneumophila, serogroup 1, was cultured from a tra-cheal aspirate. In the other case, a retrospective
diagnosis of L micdadei pneumonia (Pittsburgh pneumonia) was confirmed for the first time in a child when seroconversion was identified during a
survey of unselected serum samples from 255
hos-pitalized children.
MATERIALS
AND
METHODS
Specimens of pulmonary secretions were ob-tamed by aspiration with a No. 10 French suction catheter through an endotracheal tube after lavage with nonbacteriostatic normal saline. They were inoculated onto sheep blood, chocolate,
Mac-Conkey’s, and Columbia CNA agar plates and into
Brewer’s thioglycollate broth. The plates were in-cubated at 35#{176}Cto 37#{176}Cin 5% to 10% CO2 and examined at 24 and 48 hours. The specimen was
also plated on buffered charcoal yeast extract agar6
for the isolation of Legionella sp. Legionellae were identified by their colonial morphology on buffered charcoal yeast extract and failure to grow on blood agar, and were speciated and serogrouped by direct fluorescent antibody testing.
pneumophila serogroups and L micdadei were ob-tamed from the Centers for Disease Control (CDC), Atlanta.
Antibody to the legionel!ae was measured by the indirect immunofluorescence method,8 using both polyvalent and monovalent antigen suspensions of
L pneumophila, serogroups 1 to 4, obtained from
the CDC. Antigen suspensions of L pneumophila, serogroups 5 and 6, and ofL micdadei were prepared in our laboratory.8 Fluorescein-conjugated goat an-tihuman immunogbobulin (G, M, and A) sera were obtained from Meloy Laboratory (Springfield, VA). The high convalescent serum antibody titer from patient 2 was discovered during a study to deter-mine the prevalence of antibody against L micdadei
in hospitalized children. Unselected sera from 255 inpatients at the Children’s Hospital of Pittsburgh, ranging in age from 1 month to 21 years, were tested for antibody to this organism. Of the 255, the serum from patient 2 was the only one with a
titer >1:128 against L micdadei. When this result was obtained, the other sera from patient 2 were located and examined for antibody to L
pneumo-phila, 1 to 4, 5, and 6 and L micdadei.
CASE REPORTS
Case 1
This 5’%2-year-old boy with acute lymphoblastic leu-kemia was undergoing reinduction with daunomycin and cytosine arabinoside for his second bone marrow relapse.
On the seventh day of chemotherapy, he suddenly devel-oped fever (40.0#{176}C)and began to vomit repeatedly. There had been no cough or prodromal symptoms.
Upon admission to Children’s Hospital of Pittsburgh,
his physical examination revealed a toxic-appearing and
very pale white boy with alopecia. His respiratory rate was 36 breaths per minute. Respirations were rapid and shallow but unlabored. There were diminished breath sounds over the left hemithorax, but no adventitious
sounds and no signs of consolidation. A soft liver edge
was palpable 3 cm below the right costa! margin and the
spleen tip was felt just under the left costa! margin. There
were no changes in sensorium.
The patient’s WBC count at the time of admission was
only 400/sL with a differential of 12% neutrophils, 80%
lymphocytes, and 8% monocytes. His hemoglobin level
was 5.8 g/dL, and his hematocrit was 16.0%. The platelet count was 36,000/L. Chest roentgenograms revealed consolidation of the left upper lobe and some minimal
increase in density in the left lower lobe. Arterial blood
gases with the patient breathing room air showed Po, 45
mm Hg with a partially compensated respiratory
alka-losis.
After cultures of blood, urine, and throat were
ob-tamed, the patient began receiving intravenous
carbeni-cillin, gentamicin, and cefamandole. Two units of packed
RBCs were transfused, and oxygen was delivered by face mask at Fi02 50%. However, over the next six hours, the
child developed increasing respiratory distress and hy-poxemia, which necessitated transfer to the intensive care
unit and intubation. This deterioration was accompanied by the development of abdominal distension and watery, nonbloody diarrhea. Findings from a chest
roentgeno-gram taken prior to intubation showed opacification of
the entire left hemithorax (Figure, top).
Following intubation, a tracheal aspirate was obtained and submitted for culture and direct fluorescent antibody
testing for Legioneila sp. Two hours later it was learned
that findings from the specimen were positive by direct
fluorescent antibody staining with polyvalent L pneu-mophila (serogroups 1 to 4) antibody. The patient was
immediately given intravenous erythromycin, 50 mg/kg! d, and the cefamandole treatment was discontinued. On
the following day, the culture of the tracheal aspirate showed a moderate growth of L pneumophila, which was subsequently identified as serogroup 1. Findings from a
tracheal aspirate obtained 24 hours after the initiation of
erythromycin therapy were positive for L pneumophila, serogroup 1, by direct fluorescent antibody staining and
by culture with light growth. Findings from routine
bac-terial and fungal cultures of blood, urine, and tracheal
aspirate were negative.
The patient remained febrile with minimal clinical
improvement, and on the fourth day of hospitalization, he developed a left pleural effusion. Thorocentesis yielded
30 mL of serosanguinous fluid which had the character-istics of a transudate. Findings from both direct
fluores-cent antibody staining and culture for Legioneila sp were
negative. At this time, after 5 days of erythromycin
therapy with minimal response, rifampin at a dose of 30 mg/kg/d via nasogastric tube was added to the
antimi-crobial regimen.
The patient was gradually weaned off the respirator and extubated, but there was no resolution. of his high fever or profound neutropenia, and there was no clearing of the consolidation showed on chest roentgenogram. A bone marrow aspirate performed after completion of a
course of daunomycin and cytosine arabinoside showed
complete replacement by lymphoblasts, and a second course of these chemotherapeutic agents was given.
On the 16th day of hospitalization, a right perihilar infiltrate was noted on the patient’s chest roentgenogram. At the same time, Candida parapsilosis was isolated from
a culture of urine and Candida albicane was recovered
from a stool culture. No sputum specimen could be ob-tamed. Intravenous amphotericin B therapy was started.
However, the patient’s condition deteriorated steadily, and he died on the 28th day of hospitalization. Permission
for an autopsy was not granted.
Acute and convalescent serology demonstrated a sig-nificant increase in titer to L pneumophila, serogroup 1,
and cross-reactivity with the other serogroups of L pneu-mophila and with L micdadei (Table).
Case 2
This 13’/2-year-old boy with acute lymphoblastic
leu-kemia, T-cell type, was undergoing reinduction with
pred-nisone, vincristine, methotrexate, and L-asparaginase for
his second bone marrow relapse. He had been receiving
Figure. Chest roentgenograms of two neutropenic children with legionellosis: top (case
1), rapid progression of findings resulting in opacification of entire left hemithorax; bottom
(case 2), infiltrate remained fairly localized.
TABLE. Reciprocal Antibody Titers to Legionella
Antigen Ca
Acute se 1
3 wk Acute
Case 2
3 wk 5 wk
Legioneila pneumophila
Serogroup 1 <16 1,024
Serogroup 2 16 128
Serogroup 3 <16 64
Serogroup 4 <16 1,024
Polyvalent 1 to 4 <16 32 16
Serogroup 5 <16 512 <16 <16 <16
Serogroup 6 <16 256 <16 <16 <16
Legioneila micdadei <16 64 <16 1,024 256
maintenance chemotherapy for 2 months prior to the
present relapse. The patient was admitted to Children’s
Hospital of Pittsburgh because of symptoms of fever and
severe stomatitis attributed to methotrexate toxicity. His
physical examination revealed a nontoxic, white
adoles-cent with cushingoid features and alopecia partialis. His
oral temperature was 38.3#{176}C,the oral mucosa was in-flamed and ulcerated, and the spleen tip was palpable. The chest was clear to auscultation at that time.
The WBC count was only 500/L with a differential
of 38% neutrophils, 4% band forms, and 56%
carbenicillin, and gentamicin.
The following morning, the patient complained of right
anterior pleuritic chest pain. A chest roentgenogram showed increased density at the right cardiophrenic an-gle. By the third day of hospitalization, this density had
progressed to a large area of consolidation of the right
lower lobe (Figure, bottom). No sputum could be
expec-torated. Findings from cultures obtained prior to
anti-biotic therapy were negative.
Fevers spiked progressively higher until the fourth day of hospitalization. Clinical improvement was coincident with gradual increase in the absolute granubocyte count.
Defervescence occurred on the sixth day of
hospitaliza-tion, and the patient was discharged after completing a ten-day course of antibiotic therapy.
A comparison of antibody titers to Legionella sp deter-mined on serum samples obtained 3 weeks before adinis-sion (acute) and 3 weeks after the onset of illness,
re-spectively, demonstrated that a seroconversion to L
mic-dadei had occurred (Table). Cross-reactivity with L
pneu-mophila, polyvalent 1 to 4, was also noted.
DISCUSSION
Our patient (case 1) with L pneumophila, sero-group 1, pneumonitis is the third reported among children with cancer; this patient is the first
re-ported in the pediatric literature to have had the
organism cultured from respiratory tract secretions. The two children previously reported2’9 with sero-logic evidence of Legionnaires’ disease complicating leukemia were in a remission and induction period of disease, respectively, had granulocytes present in their blood at some time during the period of antibiotic therapy, and both had a favorable out-come. The contribution of L pneumophila infection to the demise of our patient in irreversible relapse of his leukemia can only be speculative in the absence of a postmortem examination.
L micdadei, a more recently recognized species of the genus Legionella, was first implicated as the cause of Pittsburgh pneumonia by Myerowitz et a!
in 1979.10 Despite similarities to L pneumophikz in
growth requirements and fatty acid composition,”
L micdo,dei differs in several ways. Ultrastruc-turally, it shows a thick mucopeptide layer in the periplasmic space not seen in L pneumophikz.’2
Fluorescein-conjugated antibody against L mic-dadei stains the flagella, but not the cell body, of L pneumophikt.’3 Although serologic cross-reactivity
may occur,’4 DNA hybridization studies show less than 20% genetic relatedness between the two spe-cies.’3 In a bacteriology laboratory, L micdadei can be simply distinguished from L pneumophikz by its inability to produce 3-lactamase.1’
Other than being diagnosed almost exclusively in severely immunocompromised hosts, the clinical features of Pittsburgh pneumonia are similar to those of Legionnaires’ djsease.’5 As with our
pa-tient, most adults affected with Pittsburgh pneu-monia had been receiving steroid therapy, usually in high doses.’#{176}Although infection with L micdadei
and L pneumophila cannot be differentiated at the time of clinical presentation, this represents no therapeutic dilemma because the antibiotics eryth-romycin and rifampin appear to be equally effica-cious in both illnesses.’5
Several of the antimicrobial agents routinely used in the treatment of granubocytopenic
patients-carbenicillin and the aminoglycosides-have been
demonstrated to have good in vitro activity against both L pneumophila’6 and L micdadei.’7 However, fl-lactam and aminoglycoside antibiotics did not appear to be effective therapy for Legionelki sp
infections in guinea pigs’8”9 or in humans.’#{176}’2#{176}Thus, the favorable outcome of our patient with Pitts-burgh pneumonia is probably best interpreted as recovery unrelated to the therapy employed, rather than as evidence that antibiotics other than eryth-romycin and rifampin are efficacious.
The literature on adult patients has suggested that Legionnaires’ disease may run a more severe course in the compromised host,5 and an association with cavitation and abscess formation has been noted.2’ The combination of rifampin and erythro-mycin has been found to be at least additive, and possibly even synergistic, against L pneumophikz in vitro.’8 Furthermore, the addition of rifampin may have hastened clinical improvement in two immu-nocompromised patients,5 and the empiric addition of this antibiotic has been recommended for any patient who is not responding or who develops a complication such as lung abscess while receiving initial therapy with erythromycin.22 In view of re-cent data23 suggesting that synergistic or additive combinations of antibiotic medications may im-prove response rates in profoundly granubocyto-penic patients with Gram-negative bacteremias, it seems prudent to recommend erythromycin plus rifampin as initial therapy for neutropenic children with documented legionelbosis, especially when res-olution of the neutropenia is not anticipated for several days.
Because of these therapeutic implications, a fast, accurate diagnosis of Legionella sp infection in
im-munocompromised children is essential. Serology offers only a retrospective diagnosis. It now ap-pears, at least with L pneumophila, that subclinical or minor infection is a rather common event in the early years of life, as antibody levels are elevated in a substantial percentage of school-aged children.24 Consequently, single serum determinations are nondiagnostic. Even when seroconversion occurs, cross-reactivity with different genera of
immunosup-pressed patients may not generate an adequate antibody response to this organism to fulfill the criteria for diagnosis.2”26
Rapid diagnosis by direct fluorescent antibody
staining of respiratory tract secretions27 has been a
major advancement; however, this technique merits
further critical evaluation in view of recent data questioning its sensitivity. Using a positive culture
to define respiratory infection with L pneumophikz,
Edelstein et al found the sensitivity of direct
immunofluorescence to be only 62%, whereas that
of indirect immunofluorescence serologic studies was 75%. The specificity of direct
immunofluores-cence staining was found to be 94% when performed by experienced observers. This technique requires considerable expertise, and false-positive reactions
with other Gram-negative bacilli present in the sputum may be a problem. Culture of sputum or tracheal aspirate appears to be the only definitive
way to make a prompt diagnosis of begione!losis and
should be considered in all immunocompromised
children with pneumonia.
ACKNOWLEDGMENTS
This study was supported, in part, by Public Health
Service grant Al 17047 from the National Institute of Allergy and Infectious Diseases.
We thank Katherine Zaphyr for technical assistance and Helen Schorner for help in preparation of the man-uscript.
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