Neonatal listeriosis: Uncommon or misdiagnosed?

Clinical features and antibiotic treatment of early-onset neonatal listeriosis

OBJECTIVE

To analyze the clinical features, efficacy of antibiotic treatment, and outcome of neonatal listeriosis.

METHODS

This was a retrospective study that included all neonates diagnosed with listeriosis between January 2010 and December 2021.

RESULTS

Nine male patients and five female patients were analyzed, including 11 preterm and 3 term infants. The mean gestational age was 34 ± 2.6 weeks (29 + 2-40 + 2 weeks), and the mean birth weight was 2392 ± 603 g (1370-3580 g). The maternal clinical manifestations included fever (13/14 [92.9%]), meconium-stained amniotic fluid (12/14 [85.7%]), and intrauterine fetal distress (11/14 [78.6%]). The neonates presented with fever (14/14 [100%]), generalized maculopapular rash (7/14 [50%]), and convulsions (8/14 [57.1%]). Laboratory tests showed leukocytosis (11/14 [78.6%]), monocytosis (9/14 [64.3%]), elevated C-reactive protein levels (13/14 [92.9%]), and thrombocytopenia (6/14 [42.9%]). Eight patients had central nervous system involvement, and Listeria monocytogenes was isolated from the blood in all cases. Empiric antibiotic therapy consisted of a combination of third-generation cephalosporins and penicillin or vancomycin. Four patients died, and 10 patients were cured.

CONCLUSIONS

Preterm infants were more susceptible to listeria infection than term infants, with most having multiple organ injuries. Combined antibiotic application improved the effectiveness of treatment.

Genomic Characterization of Clinical Listeria monocytogenes Isolates in Beijing, China

Listeria monocytogenes is a foodborne human pathogen that affects public health worldwide. Whole-genome sequencing (WGS) can classify L. monocytogenes isolates and identify virulence islands and resistance genes potentially influencing infectivity. Herein, WGS was used to assess 151 L. monocytogenes isolates from 120 cases of clinical infection in Beijing, China, between 2014 and 2018. Most isolates were either serogroup 1/2a,3a or serogroup 1/2b,3b,7, with 25 multilocus sequence typing (MLST) types (STs) represented, of which ST8, ST87, and ST5 were the most common. Core-genome MLST (cgMLST) grouped the 151 isolates into 116 cgMLST types. The discriminatory power of cgMLST was greater than other subtypes, revealing that isolates from the same patient were highly related (only differing at one allele). Eighty-six isolates formed 30 complexes with ≤ 7 cgMLST alleles between neighboring isolates, suggesting possible outbreaks. Compared with isolates in the United States, ST8, ST121, ST619, ST87, and ST155 isolates were grouped into unified clades. All 151 isolates were positive for common virulence-associated loci, and 26 lineage I isolates harbored the pathogenicity island 3 (LIPI-3) locus, while 42 lineage I isolates harbored the complete LIPI-4 locus. Eleven ST619 isolates had both LIPI-3 and LIPI-4. Among the 151 isolates, 13 were resistant to at least one antibiotic, and no multidrug-resistant isolates were identified. Resistance phenotypes correlated with genotypes, apart from two meropenem resistance isolates. The findings provided insight into the nature of L. monocytogenes strains currently causing clinical disease in Beijing, and WGS analysis indicated possible outbreaks.

Listeriosis Cases and Genetic Diversity of Their L. monocytogenes Isolates in China, 2008-2019

Listeriosis, caused by Listeria monocytogenes, is a severe food-borne infection. The nationwide surveillance in China concerning listeriosis is urgently needed. In the present study, 144 L. monocytogenes isolates were collected from the samples of blood, cerebrospinal fluid (CSF), and fetal membrane/placenta in China for 12 years from 2008 to 2019. We summarized these listeriosis patients’ demographical and clinical features and outcomes. The susceptibility profile for 12 antibiotics was also determined by the broth microdilution method. Multilocus sequence typing (MLST) and serogroups of these listeria isolates were analyzed to designate epidemiological types. We enrolled 144 cases from 29 healthcare centers, including 96 maternal-neonatal infections, 33 cases of bacteremia, 13 cases of neurolisteriosis, and two cutaneous listeriosis. There were 31 (59.6%) fetal loss in 52 pregnant women and four (9.8%) neonatal death in 41 newborns. Among the 48 nonmaternal-neonatal cases, 12.5% (6/48) died, 41.7% (20/48) were female, and 64.6% (31/48) occurred in those with significant comorbidities. By MLST, the strains were distinguished into 23 individual sequence types (STs). The most prevalent ST was ST87 (49 isolates, 34.0%), followed by ST1 (18, 12.5%), ST8 (10, 6.9%), ST619 (9, 6.3%), ST7 (7, 4.9%) and ST3 (7, 4.9%). Furthermore, all L. monocytogenes isolates were uniformly susceptible to penicillin, ampicillin, and meropenem. In summary, our study highlights a high genotypic diversity of L. monocytogenes strains causing clinical listeriosis in China. Furthermore, a high prevalence of ST87 and ST1 in the listeriosis should be noted.

Sequelae of Fetal Infection in a Non-human Primate Model of Listeriosis

Listeria monocytogenes (Lm) is a common environmental bacterium that thrives on vegetation and soil matter, but can infect humans if contaminated food products are ingested, resulting in severe disease in immunosuppressed populations, including pregnant women and newborns. To better understand how the unique immunological milieu of pregnancy increases susceptibility to infection, we study listeriosis in cynomolgus macaques, a non-human primate that closely resembles humans in placentation and in the physiology, and immunology of pregnancy. Non-human primates are naturally susceptible to Lm infection, and spontaneous abortions due to listeriosis are known to occur in outdoor macaque colonies, making them ideal models to understand the disease pathogenesis and host-pathogen relationship of listeriosis. We have previously shown that Lm infection in the first trimester has a high rate of miscarriage. This study expands on our previous findings by assessing how the quantity of Lm as well as stage of pregnancy at the time of exposure may influence disease susceptibility. In the current study we inoculated a cohort of macaques with a lower dose of Lm than our previous study and although this did not result in fetal demise, there was evidence of in utero inflammation and fetal distress. Animals that were reinfected with an equivalent or higher dose of the same strain of Lm resulted in approximately half of cases continuing to term and half ending in fetal demise. These cases had inconsistent bacterial colonization of the fetal compartment, suggesting that Lm does not need to directly infect the placenta to cause adverse pregnancy outcomes. Timed surgical collection of tissues following inoculation demonstrated that transmission from mother to fetus can occur as soon as 5 days post-inoculation. Lastly, third trimester inoculation resulted in pregnancy loss in 3 out of 4 macaques, accompanied by characteristic pathology and Lm colonization. Collectively, our studies demonstrate that common laboratory culture tests may not always recover Lm despite known maternal ingestion. Notably, we also find it is possible for maternal infection to resolve in some cases with no discernible adverse outcome; however, such cases had evidence of a sterile intrauterine inflammatory response, with unknown consequences for fetal development.

Should arboviruses be the only diagnosis hypothesis in pregnant women in endemic areas presenting with a rash?

Listeria is an unusual pathogen that causes neonatal infection with high morbidity and mortality. We present the case of a premature newborn whose mother had a rash during pregnancy; the newborn had severe early sepsis because of Listeria monocytogenes and histopathologically suggestive findings of the placenta. Obstetricians and neonatologists should suspect listeriosis in cases with compatible epidemiological history, clinical features, and examination findings of the placenta.

Listeriosis in mainland China: A systematic review

OBJECTIVE

The aim of this study was to conduct a systematic review to better understand the epidemiological and clinical characteristics of listeriosis patients in mainland China.

METHODS

The six most widely used Chinese and English language databases were searched. The records of patients with listeriosis in mainland China reported during the years 2011-2017 were extracted. The clinical data of patients and information on clinical isolates of Listeria were collected and analyzed.

RESULTS

In total, 136 records were identified, reporting 562 patients with listeriosis. The number of patients was much higher than that reported in the previous decade. The 227 non-perinatal listeriosis patients included had a mortality rate of 23.78%. Of the 231 perinatal listeriosis patients, 32.68% resulted in abortion and/or newborn death. All listeriosis cases were reported as being sporadic. The listeriosis was traced to infection via a meat product in only three patients, while 33.12% were healthcare-associated infections.

CONCLUSIONS

The number of patients with listeriosis in mainland China may have been underestimated previously. Perinatal cases in mainland China account for a much higher proportion than is usually described. Considering the high number of listeriosis patients in China, a comprehensive monitoring system for Listeria is urgently needed.

Listeriosis in two twin pregnancies after in vitro fertilization with differential outcome and literature review

PURPOSE

In vitro fertilization (IVF) has become a very common procedure in the infertility practice due to its accessibility. The study is aiming at presenting two twin pregnancy-related infections caused by Listeria monocytogenes and reviewing the reported cases of listeriosis in multiple pregnancies.

MATERIALS AND METHODS

Two listeriosis cases with twin pregnancy after IVF were described and the literature on pregnancy-associated listeriosis was reviewed.

RESULTS

The risk of listeriosis should be underscored in pregnant women after IVF, and timely diagnosis and rational treatment might result in a better outcome.

CONCLUSIONS

The current study highlights that the infections due to L. monocytogenes should be noted in multiple pregnancies after IVF.