Perinatal listeriosis--a review of twelve patients

Listeriosis in infants: Prospective surveillance studies in Canada and Switzerland

Objectives

International data on listeriosis during infancy from large populations are essential to guide evidence-based empiric antibiotic guidelines for sepsis in infancy. We aimed to determine the incidence, clinical manifestations, and outcome of listeriosis in infants <6 months of age in Canada and Switzerland.

Methods

Prospective, active surveillance of listeriosis in infants <6 months of age was conducted through the Canadian Paediatric Surveillance Program (May 2015 to April 2017) and the Swiss Paediatric Surveillance Unit (April 2017 to March 2018). Confirmed and probable cases were included.

Results

In Canada, eight sporadic listeriosis cases were reported (incidence, 1.1/100,000 live births/year). In Switzerland, four cases were reported (incidence, 4.5/100,000 live births/year) of which three were part of a confirmed outbreak with an unclear source. In the two countries, eight of the 12 cases (66.6%) presented as early-onset disease (within the first 7 days of life) and none presented after 28 days life.

Conclusions

Neonatal listeriosis is rare. Infants presenting with sepsis, especially after 4 weeks of life, may not routinely require empiric antibiotic coverage for listeriosis. Outbreak-related cases still occur. Continued surveillance is important.

Placental Lesions in Meconium Aspiration Syndrome

Background

Meconium aspiration syndrome (MAS) is defined by respiratory distress requiring supplemental oxygen in a meconium-stained neonate. MAS is clinically subclassified as mild, moderate, and severe according to the oxygen requirement. The aims of this study were to compare the histological findings in the placentas of MAS neonates with those of meconium-stained but non-MAS neonates and to analyze the correlation between the severity of MAS and the grade of its histological parameters.

Methods

We collected 160 singleton term placentas from neonates with meconium staining at birth from a tertiary medical center, Seoul, Republic of Korea. We reviewed hematoxylin and eosin sections of tissue samples (full-thickness placental disc, chorioamniotic membranes, and umbilical cord).

Results

Funisitis was present more frequently in MAS than in non-MAS (p < .01), of which the stage was correlated with the severity of MAS (p < .001). The histological findings consistent with maternal underperfusion and chronic deciduitis were more frequent in MAS than in non-MAS (p < .05). There was a correlation between the degree of chorionic vascular muscle necrosis and the severity of MAS (p < .05).

Conclusions

Our results suggest that fetal inflammatory response evidenced by funisitis occurs prenatally in MAS and that the stage of funisitis and of chorionic vascular muscle necrosis may be a predictive marker of the severity of MAS.

Meconium aspiration syndrome: a role for fetal systemic inflammation

BACKGROUND

Meconium aspiration syndrome (MAS) is a leading cause of morbidity and mortality in term infants. Meconium-stained amniotic fluid (MSAF) occurs in approximately 1 of every 7 pregnancies, but only 5% of neonates exposed to MSAF develop MAS. Why some infants exposed to meconium develop MAS while others do not is a fundamental question. Patients with MSAF have a higher frequency of intraamniotic inflammation/infection than those with clear fluid. We propose that fetal systemic inflammation is a risk factor for the development of MAS in patients with MSAF.

OBJECTIVE

We sought to investigate whether intraamniotic inflammation and funisitis, the histopathologic landmark of a fetal inflammatory response, predispose to MAS.

STUDY DESIGN

A prospective cohort study was conducted from 1995 through 2009. Amniotic fluid (AF) samples (n = 1281) were collected at the time of cesarean delivery from women who delivered singleton newborns at term (gestational age ≥38 weeks). Intraamniotic inflammation was diagnosed if the AF concentration of matrix metalloproteinase-8 was >23 ng/mL. Funisitis was diagnosed by histologic examination if inflammation was present in the umbilical cord.

RESULTS

The prevalence of MSAF was 9.2% (118/1281), and 10.2% (12/118) of neonates exposed to MSAF developed MAS. There were no significant differences in the median gestational age or umbilical cord arterial pH at birth between neonates who developed MAS and those who did not (each P > .1). Mothers whose newborns developed MAS had a higher median of AF matrix metalloproteinase-8 (456.8 vs 157.2 ng/mL, P < .05). Newborns exposed to intraamniotic inflammation had a higher rate of MAS than those who were not exposed to intraamniotic inflammation [13.0% (10/77) vs 0% (0/32), P = .03], as did those exposed to funisitis [31.3% (5/16) vs 7.3% (6/82); relative risk, 4.3; 95% confidence interval, 1.5-12.3]. Among the 89 newborns for whom both AF and placental histology were available, MAS was more common in patients with both intraamniotic inflammation and funisitis than in those without intraamniotic inflammation and funisitis [28.6% (4/14) vs 0% (0/28), P = .009], while the rate of MAS did not show a significant difference between patients with intraamniotic inflammation alone (without funisitis) and those without intraamniotic inflammation and funisitis [10.9% (5/46) vs 0% (0/28)].

CONCLUSION

The combination of intraamniotic inflammation with fetal systemic inflammation is an important antecedent of MAS. This concept has implications for the understanding of the mechanisms of disease responsible for MAS and for the development of prognostic models and therapeutic interventions for this disorder.

Bacteria and endotoxin in meconium-stained amniotic fluid at term: could intra-amniotic infection cause meconium passage?

BACKGROUND

Meconium-stained amniotic fluid (MSAF) is a common occurrence among women in spontaneous labor at term, and has been associated with adverse outcomes in both mother and neonate. MSAF is a risk factor for microbial invasion of the amniotic cavity (MIAC) and preterm birth among women with preterm labor and intact membranes. We now report the frequency of MIAC and the presence of bacterial endotoxin in the amniotic fluid of patients with MSAF at term.

MATERIALS AND METHODS

We conducted a cross-sectional study including women in presumed preterm labor because of uncertain dates who underwent amniocentesis, and were later determined to be at term (n = 108). Patients were allocated into two groups: (1) MSAF (n = 66) and (2) clear amniotic fluid (n = 42). The presence of bacteria was determined by microbiologic techniques, and endotoxin was detected using the Limulus amebocyte lysate (LAL) gel clot assay. Statistical analyses were performed to test for normality and bivariate comparisons.

RESULTS

Bacteria were more frequently present in patients with MSAF compared to those with clear amniotic fluid [19.6% (13/66) versus 4.7% (2/42); p < 0.05]. The microorganisms were Gram-negative rods (n = 7), Ureaplasma urealyticum (n = 4), Gram-positive rods (n = 2) and Mycoplasma hominis (n = 1). The LAL gel clot assay was positive in 46.9% (31/66) of patients with MSAF, and in 4.7% (2/42) of those with clear amniotic fluid (p < 0.001). After heat treatment, the frequency of a positive LAL gel clot assay remained higher in the MSAF group [18.1% (12/66) versus 2.3% (1/42), p < 0.05]. Median amniotic fluid IL-6 concentration (ng/mL) was higher [1.3 (0.7-1.9) versus 0.6 (0.3-1.2), p = 0.04], and median amniotic fluid glucose concentration (mg/dL) was lower [6 (0-8.9) versus 9 (7.4-12.6), p < 0.001] in the MSAF group, than in those with clear amniotic fluid.

CONCLUSION

MSAF at term was associated with an increased incidence of MIAC. The index of suspicion for an infection-related process in postpartum women and their neonates should be increased in the presence of MSAF.

Listeriosis in human pregnancy: a systematic review

Listeria is commonly found in processed and prepared foods and listeriosis is associated with high morbidity and mortality. Preventative measures are well prescribed and monitoring and voluntary recall of contaminated products has resulted in a 44% reduction in the prevalence of perinatal listeriosis in the USA. Pregnant women are at high risk for listeriosis, but symptoms are non-specific and diagnosis is difficult. The intracellular life-cycle of Listeria protects the bacterium from host innate and adaptive immune responses. Antibiotic treatment requires agents able to penetrate, distribute, and remain stable within host cells. Prolonged use of high-dose ampicillin can significantly improve neonatal outcome.

Incidence of chorioamnionitis in patients with meconium-stained amniotic fluid

Objective: The goal of this study was to determine if meconium staining of the amniotic fluid (MSAF) is a marker for chorioamnionitis.

Methods: In a retrospective, case-control investigation, we studied 100 patients with MSAF. Each patient was matched with a control who delivered during the same period but did not have MSAF. Subjects and controls were matched for age, parity, gestational age, mode of delivery, duration of rupture of membranes (ROM), length of internal monitoring, and number of examinations before and after ROM. The incidence of chorioamnionitis in controls and study patients was compared. The diagnosis of chorioamnionitis was based on clinical examination.

Results: Thirteen of the 200 patients [6.5%, 95% confidence interval (CI), 2.5–10.5%] developed chorioamnionitis. Of the 100 women with MSAF, 10 (10%, 95% CI, 4–16) were infected compared with only 3 controls (3%, 95% CI, 0–6, P = 0.04). The odds ratio (OR) for this comparison was 3.3, and the 95% CI was 1.02–10.63.

Conclusions: MSAF is associated with an increased frequency of chorioamnionitis. Several factors could explain this association. Infection may cause fetal stress, leading to the release of meconium. MSAF may enhance the growth of bacteria by providing a rich medium of essential nutrients or growth stimulants. MSAF also may impair the host immune system so that chemotaxis or phagocytosis is diminished, thus allowing accelerated growth of microorganisms.

Meconium in the amniotic fluid of pregnancies complicated by preterm premature rupture of membranes is associated with early onset neonatal sepsis

OBJECTIVE

This study was to determine the significance of meconium in the amniotic fluid of pregnancies complicated by preterm premature rupture of membranes (PPROM) without labor.

METHODS

A case-control study of 31 pregnancies complicated by PPROM at 27-36 weeks gestation with meconium present (study group) and 93 pregnancies complicated by PPROM but without meconium was performed. The patients were matched for year of delivery, gestational age, race, and parity. Pregnancy and neonatal outcome variables of the 2 groups were compared.

RESULTS

The incidence of early onset neonatal sepsis was significantly increased in the study group (16.1% vs. 1.1%; P < 0.001). Similarly, chorioamnionitis (48.3% vs. 22.5%; P < 0.01), cesarean delivery for a nonreassuring fetal heart rate pattern (19.4% vs. 3.2%; P < 0.01), a 5-min Apgar score < 7 (22.5% vs. 8.6%; P < 0.05), and fetal growth retardation (FGR) (12.9% vs. 2.2%; P < 0.05) were also more common in pregnancies complicated by PPROM with meconium. The mean umbilical cord arterial pH was significantly lower in these pregnancies (7.18 +/- 0.07 vs. 7.28 +/- 0.08; P < 0.001). After controlling for confounding variables with multiple logistic regression analysis, we found that meconium in the amniotic fluid remained associated with early onset neonatal sepsis.

CONCLUSIONS

The presence of meconium in the amniotic fluid of pregnancies complicated by PPROM is associated with an increased incidence of early onset neonatal group B beta-hemolytic streptococcus (GBBS) sepsis.

Preterm meconium staining of the amniotic fluid: associated findings and risk of adverse clinical outcome

BACKGROUND

The incidence of preterm meconium staining of the amniotic fluid (MSAF) is uncertain. It may be an indicator of possible listeriosis. It is unclear how great this risk is or whether preterm MSAF is a risk factor for adverse neonatal outcome.

OBJECTIVE

To investigate the incidence of preterm MSAF, the incidence of associated maternal and neonatal infection, and the outcomes of the infants at discharge.

DESIGN

Retrospective case-control study.

METHODS

Infants < 33 weeks gestation with preterm MSAF born in the Simpson Memorial Maternity Pavilion, Edinburgh between 1 January 1994 and 2 January 2001 were matched with the next infant of the same sex and gestation with clear liquor. Maternal and infant characteristics, culture results, placental histology, and clinical outcomes were compared.

RESULTS

Preterm MSAF was observed in 45/1054 (4.3%) infants below 33 weeks gestation. No maternal or infant listeriosis was identified in cases or controls. There was no significant difference in birth weight, Apgar score, or first pH between cases and controls. Preterm MSAF was associated with prolonged rupture of the membranes (odds ratio (OR) 3.34, 95% confidence interval (CI) 1.07 to 10.49), but not maternal hypertension, sepsis, or chorioamnionitis. Severe (grade 3/4) intraventricular haemorrhage was significantly more common in infants with preterm MSAF (OR 2.03, 95% CI 1.62 to 2.53). There was no significant difference in mortality. Early onset sepsis was observed in two cases and three controls.

CONCLUSIONS

Preterm meconium staining of the amniotic fluid may be associated with increased risk of intraventricular haemorrhage. It does not appear to be a useful indicator of listeriosis.

The infectious origins of stillbirth

OBJECTIVE

Our objective was to determine the relationship between various types of perinatal infections and stillbirths.

STUDY DESIGN

By use of various textbooks on perinatal infections, multiple MEDLINE searches, and the reference list of all appropriate manuscripts, the appropriate English language literature was reviewed to define the relationship between various perinatal infections and stillbirths.

RESULTS

Infection may cause stillbirth by a number of mechanisms, including direct infection, placental damage, and severe maternal illness. A large variety of organisms have been associated with stillbirth, including many bacteria, viruses, and protozoa. In developed countries, between 10% and 25% of stillbirths may be caused by an infection, whereas in developing countries, which often have much higher stillbirth rates, the contribution of infection is much greater. Ascending bacterial infection, both before and after membrane rupture, with organisms such as Escherichia coli, group B streptococci, and Ureaplasma urealyticum is usually the most common infectious cause of stillbirth. However, in areas where syphilis is very prevalent, up to half of all stillbirths may be caused by this infection alone. Malaria may be an important cause of stillbirth in women infected for the first time in pregnancy. The two most important viral causes of stillbirth are parvovirus and Coxsackie virus, although a number of other viral infections appear to be causal. Toxoplasma gondii, leptospirosis, Listeria monocytogenes, and the organisms that cause leptospirosis, Q fever, and Lyme disease have all been implicated as etiologic for stillbirth.

CONCLUSION

Because infection-related stillbirth is relatively rare in developed countries, and those that do occur are caused by a wide variety of organisms, reducing this etiologic component of stillbirth much further will be difficult. However, in certain developing countries, the stillbirth rate is so high and the infection-related component so great that achieving a substantial reduction in stillbirth should be possible simply by reducing maternal infections.

Listeriosis during pregnancy

Listeriosis is an uncommon infection that has a unique predilection for pregnant women and may result in pregnancy loss. Contaminated food is the usual source of infection, and increased federal surveillance of foodstuffs is the most effective strategy for prevention of disease. Although dramatic epidemics have received the most publicity, more cases of perinatal listeriosis are isolated. If Listeria chorioamnionitis is diagnosed preterm, in contrast to other types of chorioamnionitis, in utero therapy with high-dose penicillin or trimethoprim-sulfamethoxazole is possible, and preterm delivery may be avoided. The clinical characteristics of neonatal listeriosis are similar to neonatal Group B Streptococcus sepsis, with early and late onset forms of disease. The epidemiology, diagnosis, and management of Listeria infection in pregnancy are reviewed.

Pathophysiology, diagnosis, and management of intraamniotic infection

Intraamniotic infection (IAI) is a term used to describe a clinically diagnosed infection of the contents of the uterus. It is found most often after rupture of the membranes. The most useful diagnostic tests are physical examination, amniotic fluid glucose determination, and amniotic fluid Gram's stain. There is no clearly established means for the prevention of IAI, but cervical examinations and cervical manipulation can increase the risk, so caution with their use is still warranted. Treatment for this infection should be initiated when the diagnosis is made to provide the lowest risk of neonatal and maternal complications. Ampicillin or penicillin plus gentamicin are the most extensively tested antibiotics for treatment before delivery. Clindamycin or metronidazole should be added if a cesarean section is performed. As a general rule, antibiotics should be continued postpartum until the patient has been afebrile and asymptomatic for a minimum of 24 hours. Neonatal complications of IAI may be substantial especially for the premature fetus. Women with this infection have a greater risk for dysfunctional labor and cesarean section.

A case of congenital Listeria septicemia associated with high levels of inflammatory cytokines

A case of congenital Listeria septicemia is reported. A 2256 g male infant suffering from respiratory and circulatory failure with shock-like symptoms and high levels of inflammatory cytokines (tumor necrosis factor-alpha, interleukin-1 beta, -6, and -8), was admitted to the Morioka Red Cross Hospital. Listeria monocytogenes was cultured from cord blood, contents from the external ear canal, rectum and stomach. The infant was treated with surfactant replacement as well as conventional therapy. The high levels of interleukin-1 beta decreased with the improvement of the circulatory function, which might have been the major cause of the poor clinical state.

Perinatal infection with Listeria monocytogenes

Listeria monocytogenes has been increasingly recognized as a cause of intrauterine sepsis with associated perinatal wastage. The condition is mostly acquired through dietary intake and appropriate advice should be given to all pregnant women. The most common presentations in pregnancy include premature labour, an influenza-like illness and reduced fetal movements. In this report, we present a series of 24 cases of perinatal listeria infection presenting to either our obstetric or neonatal units and confirmed by the microbiology department of the hospital. In particular, we wish to highlight 3 cases in which antenatal diagnosis and aggressive therapy was associated with a successful outcome. Amongst the remaining 21 cases in which an antenatal diagnosis was not made, there were 5 perinatal deaths and 1 mid-trimester loss at 18 weeks. Clinicians must maintain a high index of suspicion for listeria, particularly in gravid patients who present with fever in the setting of a persistent 'flu-like' illness and premature labour. Once suspected, appropriate specimens for listeria culture should include blood, cervical swabs and midstream urine. Empirical antibiotic therapy with amoxicillin should be instituted while waiting for culture results in patients with possible Listeria monocytogenes sepsis.

Congenital listeriosis: case reports and review of literature

Four babies with congenital listeriosis were diagnosed in the Prince of Wales Hospital in Hong Kong in 1990-1991. Two died in the early neonatal period. The remaining 2 survived and recovered with no sequelae. The clinical and pathological features of these babies, together with those reported in the recent literature are highlighted so as to raise a high index of suspicion toward this disease and hopefully prompt treatment can be offered.

The epidemiology of neonatal respiratory disease

The epidemiology of many conditions affecting the newborn infant is influenced by the health of the mother, prematurity and the effects of medical and obstetric management. In this review we have considered the role of each of these factors in seven respiratory conditions presenting in the newborn infant.

Listeria monocytogenes. The role of transabdominal amniocentesis in febrile patients with preterm labor

Two women with preterm labor and intraamniotic infection with Listeria Monocytogenes are presented. In both patients, the prenatal diagnosis of Listeriosis was made by transabdominal amniocentesis. The immediate prominent observation was meconium staining of the amniotic fluid. We propose that an amniocentesis should be performed in women with premature labor and fever. If the amniotic fluid is meconium stained and the Gram stain examination reveals Gram positive rods, Listeria Monocytogenes should be suspected and the patient should be treated accordingly until the culture results are obtained.

Listeria monocytogenes, a food-borne pathogen

The gram-positive bacterium Listeria monocytogenes is an ubiquitous, intracellular pathogen which has been implicated within the past decade as the causative organism in several outbreaks of foodborne disease. Listeriosis, with a mortality rate of about 24%, is found mainly among pregnant women, their fetuses, and immunocompromised persons, with symptoms of abortion, neonatal death, septicemia, and meningitis. Epidemiological investigations can make use of strain-typing procedures such as DNA restriction enzyme analysis or electrophoretic enzyme typing. The organism has a multifactorial virulence system, with the thiol-activated hemolysin, listeriolysin O, being identified as playing a crucial role in the organism's ability to multiply within host phagocytic cells and to spread from cell to cell. The organism occurs widely in food, with the highest incidences being found in meat, poultry, and seafood products. Improved methods for detecting and enumerating the organism in foodstuffs are now available, including those based on the use of monoclonal antibodies, DNA probes, or the polymerase chain reaction. As knowledge of the molecular and applied biology of L. monocytogenes increases, progress can be made in the prevention and control of human infection.

Progress in pathogenesis and management of clinical intraamniotic infection

In the past decade, gratifying progress has been achieved in our understanding of clinical intraamniotic infection. With a usual incidence of 1% to 4%, clinical intraamniotic infection mainly develops as an ascending process after prolonged rupture of the membranes and labor, but other cases may be hematogenous in origin whereas still others complicate intrauterine procedures. The most common organisms isolated in amniotic fluid of cases of intraamniotic infections are anaerobes, genital mycoplasmas, group B streptococci, and Escherichia coli. The latter two are found most commonly in maternal or neonatal bacteremia complicating intraamniotic infection. Although the diagnosis remains largely a clinical one, laboratory tests have been suggested to confirm the diagnosis in women with symptoms. These include amniotic fluid Gram stain, gas-liquid chromatography, and leukocyte esterase measurement. Maternal treatment consists of antibiotic therapy and delivery. Studies to date have used a penicillin plus an aminoglycoside, with some authors advocating the addition of clindamycin after cesarean delivery. Other broad-spectrum regimens may be equally effective. Complications of clinical intraamniotic infections include an increase in cesarean section rate and in maternal and neonatal bacteremia. Poor neonatal outcomes in intraamniotic infection are more likely in the following cases: (1) when E. coli or group B streptococci are present in the amniotic fluid; (2) when the infant has a low birth weight; (3) when maternal antibiotic therapy is delayed until after delivery.

Meconium-stained amniotic fluid: a risk factor for microbial invasion of the amniotic cavity

The purpose of this study was to determine whether meconium-stained amniotic fluid is a marker for microbial invasion of the amniotic cavity. Amniocentesis was performed on 707 patients presenting with preterm labor and intact membranes. Meconium-stained amniotic fluid was present in 4.2% (30/707) of patients with preterm labor. The prevalence of positive amniotic fluid cultures was significantly higher in women with meconium-stained amniotic fluid than in women with clear fluid (33% [10/30] vs 11% [75/677]; p = 0.001; odds ratio = 4.01; 95% confidence interval = 1.6 to 9.4). Patients with meconium-stained amniotic fluid were also more likely to have failed tocolysis and delivered a preterm neonate more frequently than patients with clear fluid (83% [25/30] vs 38% (258/677); p = 0.0001; odds ratio = 8.1; 95% confidence interval = 2.9 to 24.4). We conclude that meconium-stained amniotic fluid is a risk factor for microbial invasion of the amniotic cavity and preterm delivery in women with preterm labor and intact membranes.

Perinatal listeriosis; more common than reported (2 case reports and revision of literature)

Listeriosis is again reported with an increasing frequency in recent literature. It is reported to be the third cause of neonatal sepsis [4,7]. Hereby we are presenting two cases of perinatal listeriosis together with a summary of literature.

Outbreak of neonatal listeriosis in a regional hospital in Kuwait

Six newborns with Listeria monocytogenes infection were admitted to the same neonatal unit between 31 October and 3 December 1985. The index case, a preterm baby, was born to a mother who was febrile with an influenza-like illness at the time of delivery. This baby presented with Listeria sepsis and pneumonia. Another child was born from whose mother L. monocytogenes was isolated from the cervix with the same serotype as that in the CSF of her newborn. In the other cases blood and cervical cultures of the mothers were negative, while Listeria was isolated from the CSF of their babies. Five out of six infants developed meningitis between 9 and 12 days after birth. All isolates were serotype 4b and indistinguishable by phage typing. All babies were successfully treated without any major sequelae. Although cross-infection was strongly suggested, the source of the outbreak could not be established. This is the first documented report of human listeriosis in Kuwait.

Neonatal listeriosis: experience in Suffolk

Four cases of neonatal infection with Listeria monocytogenes are reported. Two of them resulted in neonatal death and two in long-term healthy survival. The literature on the subject is reviewed with particular reference to epidemiology, early recognition and treatment.

Perinatal listeriosis underdiagnosed as a cause of pre-term labour?

Between April 1, 1985, and April 1, 1986, four cases of perinatal listeriosis were reported at the Maastricht Academic Hospital. All cases were of the early-onset type. All mothers were admitted for pre-term labour between 28 and 33 weeks of gestation. Pre-natal symptoms included maternal fever, non-characteristic influenza-like manifestations, leucocytosis and (pre-term) meconium-stained amniotic fluid. Two neonates died, one in utero and one due to listeriosis sepsis. Another neonate developed a hydrocephalus. Only one neonate has survived without damage up to now. Such a high incidence of listeriosis and the high perinatal morbidity and mortality rates are remarkable. Epidemiological, bacteriological and placental sequelae of Listeria monocytogenes are discussed.

Neonatal listeriosis: a report of seven cases

Seven neonates with listeriosis admitted to Farwaniya Hospital, Kuwait, are reported. Six had the meningitic type and one the septicaemic type. Serotyping showed 1/4b in all neonates. The response to 2 weeks ampicillin and amikacin was excellent with no mortality or morbidity.

Listeria monocytogenes neonatal meningitis in The Netherlands

As part of a collaborative study of the epidemiology of bacterial meningitis, the bacteriological data and some clinical features concerning neonates with Listeria monocytogenes meningitis were analysed for the period 1976-1982. In this group of 12 patients the case mortality rate was 17%. Seventeen per cent of the children weighed less than 2500 g at birth. Sixty-seven % of the cases occurred in the absence of any known risk factor. Listeria monocytogenes type IV B was isolated in 75% of the cases.

In vitro and in vivo studies of imipenem-cilastatin alone and in combination with gentamicin against Listeria monocytogenes

Imipenem was evaluated for its in vitro and in vivo activities alone and in combination with gentamicin against a clinical isolate of Listeria monocytogenes, and the results were compared with the activities of ampicillin with and without gentamicin. In vitro, the MBC of imipenem was fourfold less than that of ampicillin. Checkerboard determinations of the MBCs exhibited a synergistic response for imipenem-gentamicin but an indifferent response for ampicillin-gentamicin. In vivo studies with experimental bacteremia and meningitis due to L. monocytogenes in newborn rats revealed that both imipenem-cilastatin and ampicillin at a dose of 50 mg/kg produced excellent bactericidal titers in serum. Overall mortality rates were not significantly different among four groups of animals receiving imipenem-cilastatin, imipenem-cilastatin-gentamicin, ampicillin or ampicillin-gentamicin. However, imipenem-cilastatin alone or in combination with gentamicin was significantly less effective than ampicillin-gentamicin, as judged by the rapidity of clearance of bacteria from blood, liver, and spleen. These findings suggest that imipenem-cilastatin and imipenem-cilastatin-gentamicin may not be suitable alternatives for the treatment of listeriosis.

A study of 280 cases of neonatal meningitis in The Netherlands

Within the framework of a more extensive study of the epidemiology of bacterial meningitis in The Netherlands (1976-1982), 280 cases of neonatal meningitis were investigated retrospectively. Escherichia coli (132 cases, 47%), Streptococcus agalactiae (68 cases, 24%), Listeria monocytogenes (12 cases, 4%) were the organisms most commonly isolated. The mortality rate for these 280 cases was 27%. The male-female ratio was 1.33:1. The minimum incidence for The Netherlands was calculated to be 23 per 100 000 live births.

Listeria and gram-negative bacillary meningitis in New York City, 1972-1979. Frequent causes of meningitis in adults

In an eight year period (1972-1979), 158 cases of enteric gram-negative bacillary meningitis and 53 cases of Listeria meningitis were reported to the New York City Health Department. These two forms of bacterial meningitis were the fourth and fifth most common ones reported to the Department, respectively. The cumulative total of reported cases of gram-negative rod meningitis over this less than the reported cases due to Neisseria meningitis over this period. In contrast to most previous studies of Listeria and enteric gram-negative meningitides, the majority of cases occurred in adults. Listeria meningitis occurred more often in immunosuppressed hosts and the elderly than in the newborn; gram-negative bacillary meningitides were seen more often in elderly septic patients and in patients with traumatic skull fracture than in infants during the first months of life. The over-all mortality of Listeria meningitis was 62 percent; that of the combined gram-negative meningitides 71.3 percent. The mortality in adults with Escherichia coli and Klebsiella meningitis who were treated with chloramphenicol as the major antibiotic was 83 percent. In comparison, the only appreciable survival rates noted were in those with Listeria, Escherichia coli, Proteus mirabilis and Salmonella meningitis who were treated with ampicillin alone in whom the over-all mortality was 51 percent.