Indian Journal of Medical Microbiology Medknow Publications on behalf of Indian Association of Medical Microbiology ISSN: 0255-0857 EISSN: 1998-3646 Vol. 28, Num. 4, 2010, pp. 385-387

Indian Journal of Medical Microbiology, Vol. 28, No. 4, October-December, 2010, pp. 385-387

Case Report

Neonatal listeriosis: A case report from sub-Himalayas

KK Mokta¹, AK Kanga¹, RK Kaushal²

¹ Department of Microbiology, IGMC, Shimla, India
² Department of Paediatrics, IGMC, Shimla, India
Correspondence Address:
K K Mokta, Department of Microbiology, IGMC, Shimla, India
kiranmokta@yahoo.in

Date of Submission: 27-Jan-2009
Date of Acceptance: 21-Jul-2010

Code Number: mb10112

PMID: 20966576
DOI: 10.4103/0255-0857.71824

Abstract

Keywords: Listeria monocytogenes, neonatal listeriosis, perinatal listeriosis

Introduction

Listeria monocytogenes , an uncommon cause of illness in general population, is an important cause of life-threatening bacteraemia in certain groups like neonates, pregnant women, elderly people, transplant recipients and others with impaired cell-mediated immunity. ^[1] Pregnant women have 17-fold increased risk of developing listerial bacteraemia, two-third of babies born to such mothers develop clinical listeriosis. The source of infection is generally from animals through undercooked meat or chicken. ^[2] Neonates acquire infection by transplacental spread, aspiration of infected meconium or in rare instances of cross-contamination in newborn nurseries. Even with appropriate treatment, the overall mortality with listeriosis is 30%. ^[3] Listeriosis occurs as sporadic or epidemic form throughout the world, with majority of cases reported from western countries. Few cases are reported from India either due to its rarity or failure to recognize the bacterial growth on culture media. We report a rare case of neonatal listeriosis from Himachal Pradesh.

Case Report

A two-day-old male baby was admitted in a paediatric department of a tertiary-care hospital with fever, listlessness, skin rash, and non-acceptance of feed. The full term baby born to a booked fourth-gravida mother by vaginal delivery at the peripheral hospital, weighed 3 kg at birth. The baby was meconium stained and did not cry immediately after birth. After 16 h, he developed fever, irritability, excessive cry, non-acceptance of feed and skin rash. He was put on ceftriaxone with provisional diagnosis of septicaemia and next day referred to Indira Gandhi Medical College (IGMC), Shimla. On examination, he was febrile and listless with maculopapular rash on face, trunk, and thighs. The umbilicus was healthy and there was no focal neurological deficit. Heart rate and respiratory rate were 140/minute and 70/minute, respectively. Total leukocyte count was 11 000/mm ³ with 68% neutrophils and C-reactive protein was positive.

The antenatal period of mother was uneventful and there was no history of prolonged rupture of membranes or foul-smelling liquor. Her first child was 8-year-old and subsequent pregnancies ended in spontaneous abortions at 3rd and 4th month of gestation. Investigations for Toxoplasma, Rubella, H. simplex type 1 and 2 by ELISA were negative. Both husband and wife were non-reactive for syphilis by VDRL test. There was no H/O diabetes mellitus, smoking, alcohol or drug intake. Other investigations in the antenatal period were normalCerebrospinal fluid and blood samples of baby were received in microbiology department. CSF was turbid and direct microscopy revealed pleocytosis with 80% polymorphonuclear cells. Direct smear of CSF revealed gram-positive coccobacilli along with polymorphonuclear cells on Gram staining [Figure - 1]. Rapid antigen detection test done with Wellcogen antigen detection kit was negative for S. pneumoniae, group B streptococcus, N. meningitidis B/E. Coli K ₁ , N. meningitidis A/C/Y/W-135 and H. influenzae type b, the common etiological agnts of childhood bacterial meningitis. India ink and Ziehl-Neelsen staining were negative. Biochemistry of CSF was suggestive of bacterial meningitis with glucose 10 mg/dl (simultaneous blood glucose 102 mg/dl) and proteins 200 mg/dl. Centrifuged deposits of CSF were inoculated on 5% sheep blood agar, chocolate agar, nutrient agar, and MacConkey agar, and incubated at 37 ^o C with and without CO ₂ overnight. The growth revealed 1−2 mm round, convex, smooth, translucent colonies with narrow zone of beta haemolysis on 5% sheep blood agar [Figure - 2]. Colonies on nutrient agar in addition revealed bluish-tinge against transmitted light and buttermilk smell. Growth was also obtained on chocolate agar whereas no growth was seen on MacConkey agar. Gram stain of the isolate demonstrated gram-positive coccobacilli with no spore or capsule. CSF was also inoculated in brain heart infusion broth and incubated at 37, 25, and 4 ^o C later for cold enrichment. Uniform turbidity appeared in all three bottles after 48 h of incubation with gram-reaction similar to organism grown on solid media. Broths incubated at 4 and 25 ^o C demonstrated characteristic tumbling motility. The isolate was positive for methyl red and Voges Proskauer but negative for nitrate reductase and urease. It produced A/A reaction in TSI without H ₂ S. The organism fermented maltose and L-rhamnose but not D-xylose and mannitol. It was CAMP-test positive with standard strain of Staphylococcus aureus.

The isolate was identified as L. monocytogenes by colony characters, morphology, tumbling motility, ability to grow at 4 ^o C, and characteristic biochemical reactions. ^[4] Listeria monocytogenes was also isolated from blood sample of the neonate. Typing of the organism was not done due to non-availability of antisera. Antimicrobial sensitivity done by Kirby Bauer's method showed the organism to be sensitive to ampicillin, co-trimoxazole, ciprofloxacin, erythromycin, gentamicin, amikacin, and resistant to ceftriaxone. Amikacin was added to the treatment on admission to IGMC,Shimla. The child deteriorated and died within few hours of admission even before the appropriate antibiotics could be started.

Vaginal and cervical swabs were taken from mother to know the carriage state and determine the likely source of infection in this term baby. The swabs were inoculated on solid and liquid media similar to CSF sample. Growth on solid media revealed mixed flora but L. monocytogenes was isolated after cold enrichment in BHI broth. Blood culture of mother was sterile.

Discussion

Listeria monocytogenes has a worldwide distribution and account for about 10% of the community-acquired meningitis. However, majority of cases are reported from western countries. The incidence of neonatal listeriosis is reported 2.2% in meconium-stained babies and 0.2% in total births in a study from North India. ^[5] Very few cases of invasive listeriosis have emerged from India, which makes clinical suspicion unlikely. ^{[5],[6],[7],[8],[9],[10],[11],[12]} In the current case, presumptive diagnosis of bacterial meningitis was considered and empirical treatment with ceftriaxone and amikacin was started. By the time the isolate from CSF was identified as L. monocytogenes, the child had unfortunately succumbed to it. It is evident from this case that empirical treatment with ceftriaxone and amikacin against community-acquired meningitis at times prove fatal if causative agent is L. monocytogenes.

Listeria monocytogenes is sensitive to penicillin, chloramphenicol, aminoglycosides, tetracyclines, and erythromycin. It is uniformly resistant to cephalosporins. Treatment of choice for listeriosis is high dose of penicillin or ampicillin, preferably in combination with aminoglycoside. Listeriosis is an emerging zoonosis that constitutes a life-threatening disease of human foetuses and neonates, elderly people, and patients with certain predisposing factors. In most human cases, the mode of infection is not known, though it probably involves ingestion of contaminated animal products or contact with infected animals. ^[12] The organism from intestine spreads by haematogenous route to any organ of the body with predilection to central nervous system and placenta. Pregnancy-associated listeriosis can occur during any stage of gestation though most cases are detected during the 3 ^rd trimester. The organism establishes itself in genital tract leading to chronic infection and infects products of conception in successive pregnancies. ^[5] Investigations of mother during antenatal period for common causes of abortion were negative in the current case. We could isolate L. monocytogenes from genital tract of mother as is also reported in some studies from India. ^[6],[7],[8] She could not be given specific treatment as she did not turn up for follow-up. The term babies suffering from listerial meningitis are most likely infected by the organism present in the vagina of carrier mother at parturition. ^[1] There were no H/O pets in the family and any other animal contact. Neonatal listeriosis occurs as early-onset and late-onset disease presenting within seven days and after seven days of birth, respectively. Meningitis is most commonly associated with late-onset disease but in this case, CNS was involved in early-onset disease as was also reported in 1979 from London. ^[13]

Laboratory diagnosis requires isolation of L. monocytogenes from normally sterile clinical specimens and identification through standard microbiologic techniques. In clinical specimen, the organism may be gram-variable and look like diphtheroids, cocci or diplococci. Laboratory misidentification as diphtheroids, streptococci or enterococci is not uncommon. The isolation of gram-positive bacilli or coccobacilli from blood or CSF should not be rejected as contaminants unless Listeria is ruled out.^[14] Antibodies to Listeriolysin O have not proved useful for acute diagnosis of invasive disease. Selected biochemical tests, demonstration of tumbling motility and haemolysis, and a typical CAMP test are usually sufficient to establish presumptive identification of L. monocytogenes.^[1] At times, CSF cytology and biochemistry can be highly suggestive of listerial meningitis. It may reveal pleocytosis with polymorphs or lymphocytes predominance, lowered or raised glucose level and elevated protein level. ^[3] The current case highlights the importance of including listerial infection in differential diagnosis of any neonate presenting with sepsis or meningitis, especially infants born to mothers of bad obstetric history. Though, there is no convincing evidence that maternal listeriosis is a cause of repeated abortions in humans but genital carriage may pose a risk-of-infection to term babies at parturition and it is safe to institute a course of amoxycillin until the problem is solved.^[1],[3] We wish to emphasize the necessity of familiarity of clinicians and clinical microbiologists with infection due to L. monocytogenes to help in early diagnosis and prompt therapeutic interventions, and in prevention of fatal outcome in such cases.

References

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