OBJECTIVENeonatal listeriosis is a relatively rare but serious disease with a high mortality rate. This study was conducted to analyze the clinical features, treatment, and outcome of 6 cases with Listeria monocytogenes septicemia confirmed by positive blood cultures.

METHODSTotally 12,538 live births delivered in the hospital from January 1, 2004 to June 30, 2006 were investigated. Differences in the time of onset of the disease, clinical presentation, illness severity, laboratory data, management, and prognosis were compared between preterm and full-term infants.

RESULTSThe incidence of neonatal listeriosis was 4.8% in this study. All the cases with listeriosis were found to have early onset and the disease was transmitted from the mother to the fetus, 4 of the cases were delivered via cesarean section, 2 were born via normal spontaneous vaginal delivery. Maternal infection before parturition presented with fever in 4, diarrhea in 1; 5 had abnormal white blood cell counts and total neutrophil counts; 1 had positive result of Listeria monocytogenes in intrauterine contents culture. Three premature infants showed signs and symptoms of severe bacterial septicemia at birth, such as reduced activity, respiratory distress, poor skin color and poor peripheral perfusion; the enlarged liver was palpable 2 - 3 cm below the right costal margin and 5 cm below the xiphoid in one; congestive rashes over the body and muscular hypotonia. Abnormal results of laboratory tests included peripheral blood white cell count (21.6 - 33.8 x 10(9))/L, total neutrophil count 0.77 - 0.83; platelet count (102 - 59 x 10(9))/L; C-reactive protein (CRP) > (160 - 118) mg/L(24 - 72 h after birth). Three preterm infants who received intensive care, accompanied by pathological changes of lungs indicated by chest X ray required assisted mechanical ventilation and 2 of them survived without sequelae but the other one died at 51 h of life. The initial clinical signs of septicemia in 3 full-term infants appeared later than preterm newborn within 62 h, 63 h and 165 h, respectively after birth. They only had fever, T 38 - 39 degrees C, with lower activity in contrast to normal newborn and without other signs and symptoms of septicemia. Accurate diagnosis of listeriosis was established by positive bacterial blood cultures. Intravenous treatment of neonatal listeriosis with ampicillin or penicillins for 1 - 2 weeks was more effective, but cephalosporins were not effective.

CONCLUSIONSThere are sporadic cases with Listeria monocytogenes infection among pregnant women in this country, resulting in severe illness of their newborn infants. Early differential diagnosis, early detection of causative organisms, especially in newborn infants infected with Listeria monocytogenes, early treatment with sensitive antibiotics can decrease the mortality rate and improve neonatal outcome. It is necessary to enhance nationwide surveillance for listeriosis.

Female ; Humans ; Infant ; Infant, Newborn ; Infant, Newborn, Diseases ; diagnosis ; microbiology ; Listeria monocytogenes ; isolation & purification ; Listeriosis ; microbiology ; Male ; Sepsis ; diagnosis ; microbiology

This study aimed to investigate the prevalence and molecular characteristics of Listeria monocytogenes in cooked products in Zigong City, China. The overall occurrence of the L. monocytogenes in the ready-to-eat (RTE) shops and mutton restaurants surveyed was 16.2% (141/873). An occurrence of 13.5% was observed in RTE pork, 6.5% in RTE vegetables, and more than 24.0% in either cooked mutton or cooked haggis. Serotype 1/2b (45.4%), 1/2a (33.3%), and 1/2c (14.2%) were the predominant types. By comparing the clonal complexes (CCs) based on multilocus sequence typing (MLST) of the L. monocytogenes from cooked foods in Zigong City and 33 listeriosis cases from different districts of China, CC87, CC9, CC8, and CC3 were showed to be prevalent in cooked products and CC87 and CC3 were the first two frequent types in the 33 clinic-source strains. All CC87 stains harbored the newly reported Listeria pathogenicity island 4 (LIPI-4) gene fragment ptsA, and all CC3 strains possessed the Listeria pathogenicity island 3 (LIPI-3) gene fragment llsX. These may increase the occurrence of the strains belonging to CC87 and CC3 in listeriosis cases in China and also underline the risk of infection owing to the consumption of the cooked products from Zigong. ST619 (serotype 1/2b) harbored both llsX and ptsA, indicating a potential hypervirulent sequence type in Zigong.
China ; epidemiology ; Cooking ; Fast Foods ; microbiology ; Food Contamination ; Food Microbiology ; Humans ; Listeria monocytogenes ; genetics ; pathogenicity ; Listeriosis ; epidemiology ; microbiology ; Meat ; microbiology ; Multilocus Sequence Typing ; Prevalence ; Seasons

We aimed to investigate the potential pathogenic profile and antibiotic resistance of Listeria monocytogenes isolated from ready-to-eat food in China. Antimicrobial resistance was determined by broth microdilution following the Clinical and Laboratory Standards Institute protocol. Molecular serotyping, virulence, and resistance genes were identified using PCR. Multi-locus sequence typing was performed on resistant strains. A total of 11.53% (113/980) isolates were resistant, from which 82.3% (93/113) harbored all the virulence genes tested. The resistant strains were subtyped into 18 sequence types (STs), from which ST2, ST5, ST8, and ST9 were involved in listeriosis. This study indicated that several L. monocytogenes isolates from ready-to-eat foods in China have pathogenic potential and are resistant to antibiotics, including antibiotics used as medicines by humans for listeriosis treatment.
Anti-Bacterial Agents ; pharmacology ; China ; epidemiology ; Drug Resistance, Multiple, Bacterial ; Fast Foods ; microbiology ; Food Microbiology ; Listeria monocytogenes ; genetics ; isolation & purification ; pathogenicity ; Listeriosis ; epidemiology ; microbiology ; Multilocus Sequence Typing ; Virulence

OBJECTIVETo study the virulent gene prevalence of foodborne Listeria monocytogenes (LM) isolated from China.

METHODS78 LM isolates derived from raw meat, cooked food, aquatic products and vegetables of 13 provinces and cities.LM isolates were investigated for prevalence of virulence genes (LIPI-1 (prfA, plcA, hly, mpl, actA, plcB); LIPI-2 (inlA, inlB), and iap) by PCR method.

RESULTS87.2% (68/78) of the isolates were prfA positive, 98.7% (77/78) of the isolates were plcA, actA and plcB positive, 97.4% (76/78) of the isolates were hly positive, 87.2% (68/78) of the isolates were mpl positive, 92.3% (72/78) of the isolates were inlA positive, 100% (78/78) of the isolates were inlB positive, 98.7% (77/78) of the isolates were iap positive. Among 21 virulent gene negative isolates, there was 7 isolates lack of two or more virulence genes. The rate of virulence genes deletion isolates from cooked meat was 31.3% (10/32), the rate of virulence genes deletion isolates from raw meat was 16.1% (5/31), the rate of virulence genes deletion isolates from vegetables was 36.4% (4/11) and rate of virulence genes deletion isolates from seafood was 50% (2/4). No significant difference was found (χ(2) = 3.721, P > 0.05). The virulence gene array-1 strains were dominant among these isolates.

CONCLUSIONAmong 78 LM isolates, prevalent of virulent genes were different except inlB, virulence genes of LIP-1 were deleted prevalently among isolates, virulence gene deletion patterns were diverse.

China ; epidemiology ; Food Contamination ; analysis ; Food Microbiology ; Foodborne Diseases ; epidemiology ; microbiology ; Listeria monocytogenes ; genetics ; isolation & purification ; pathogenicity ; Listeriosis ; epidemiology ; microbiology ; Virulence Factors ; genetics

Spontaneous bacterial peritonitis (SBP) is a life-threatening complication in patients with ascites caused by advanced liver disease. While gram negative bacteria, such as Escherichia coli and Klebsiella pneumonia are the common pathogens, Listeria monocytogenes has been recognized as a very rare pathogen. Empirical treatment with third generation cephalosporins does not provide adequate antibiotics coverage against L. monocytogenes. Diagnosis is often delayed as it requires confirmation from ascitic fluid culture. Herein, we describe the first case of SBP caused by L. monocytogenes in a patient with advanced alcoholic liver cirrhosis in Korea. Clinicians should be aware of the atypical pathogens, especially in patients with inadequate response to empirical antibiotics.
Ampicillin/therapeutic use ; Anti-Bacterial Agents/therapeutic use ; Ascites/microbiology ; Humans ; Listeria monocytogenes/*physiology ; Listeriosis/*diagnosis/drug therapy ; Liver Cirrhosis, Alcoholic/*diagnosis ; Male ; Middle Aged ; Peritonitis/*diagnosis/*microbiology

OBJECTIVETo test the effect of the c-Met inhibitor cabozantinib in inhibiting infections by Listeria monocytogenes (LM) in mice.

METHODSC57BL/6 mice at 6 weeks of age were subjected to intraperitoneal injection of LM and randomized into 4 groups for treatment with intraperitoneal injection of PBS, intragastric administration of cabozantinib (20 µg/g), intraperitoneal injection of ampicillin (Amp, 20 µg/g), or cabozantinib plus Amp. The survival curves were drawn for each group, and the number of bacteria in the blood and brain tissues was determined; serum IL-10 level and NF-κB p65 level in the cerebrospinal fluid (CSF) were assayed, and Evans Blue (EB) content and pathological changes in brain were examined.

RESULTSCompared with PBS-treated mice, the mice treated with cabozantinib showed a significantly higher survival rate, lower bacterial counts in the blood and brain (P<0.05 or 0.001), lower IL-10 (P<0.05) and NF-κB p65 levels (P<0.01), lower brain EB content (P<0.001), and milder pathological changes in the brain. The blood and brain bacterial counts (P<0.001), IL-10 (P<0.01) and NF-κB p65 levels (P<0.001), and brain EB content (P<0.001) were all significantly lower in mice treated with the combination of drugs than in mice treated with cabozantinib alone.

CONCLUSIONCabozantinib can inhibit LM infection in mice and has important values in developing new anti-intracellular infection drug.

Anilides ; pharmacology ; Animals ; Brain ; microbiology ; pathology ; Injections, Intraperitoneal ; Interleukin-10 ; blood ; Listeria monocytogenes ; drug effects ; Listeriosis ; drug therapy ; Mice ; Mice, Inbred C57BL ; Pyridines ; pharmacology ; Transcription Factor RelA ; cerebrospinal fluid

Listeria monocytogenes is an important zoonotic foodborne pathogen that can tolerate a number of environmental stresses. RsbR, an upstream regulator of the sigma B (SigB) factor, is thought to sense environmental challenges and trigger the SigB pathway. In Bacillus subtilis, two phosphorylation sites in RsbR are involved in activating the SigB pathway and a feedback mechanism, respectively. In this study, the role of RsbR in L. monocytogenes under mild and severe stresses was investigated. Strains with genetic deletion (ΔrsbR), complementation (C-ΔrsbR), and phosphorylation site mutations in the rsbR (RsbR-T175A, RsbR-T209A, and RsbR-T175A-T209A) were constructed to evaluate the roles of these RsbR sequences in listerial growth and survival. SigB was examined at the transcriptional and translational levels. Deletion of rsbR reduced listerial growxth and survival in response to acidic stress. Substitution of the phosphorylation residue RsbR-T175A disabled RsbR complementation, while RsbR-T209A significantly upregulated SigB expression and listerial survival. Our results provide clear evidence that two phosphorylation sites of RsbR are functional in L. monocytogenes under acidic conditions, similar to the situation in B. subtilis.
Alanine/genetics* ; Bacillus subtilis ; Bacterial Proteins/metabolism* ; Binding Sites ; Gene Deletion ; Gene Expression Regulation, Bacterial ; Genetic Complementation Test ; Homeostasis ; Hydrogen-Ion Concentration ; Listeria monocytogenes/metabolism* ; Listeriosis/microbiology* ; Mutation ; Phenotype ; Phosphoproteins/metabolism* ; Phosphorylation ; Sigma Factor/metabolism* ; Stress, Physiological

The incidence of diabetes mellitus is increasing among companion animals. This disease has similar characteristics in both humans and animals. Diabetes is frequently identified as an independent risk factor for infections associated with increased mortality. In the present study, homozygous diabetic (db/db) mice were infected with Listeria (L.) monocytogenes and then treated with the anti-diabetic drug exendin-4, a glucagon-like peptide 1 analogue. In aged db/db mice, decreased CD11b+ macrophage populations with higher lipid content and lower phagocytic activity were observed. Exendin-4 lowered high lipid levels and enhanced phagocytosis in macrophages from db/db mice infected with L. monocytogenes. Exendin-4 also ameliorated obesity and hyperglycemia, and improved ex vivo bacteria clearance by macrophages in the animals. Liver histology examined during L. monocytogenes infection indicated that abscess formation was much milder in exendin-4-treated db/db mice than in the control animals. Moreover, mechanistic studies demonstrated that expression of ATP binding cassette transporter 1, a sterol transporter, was higher in macrophages isolated from the exendin-4-treated db/db mice. Overall, our results suggest that exendin-4 decreases the risk of infection in diabetic animals by modifying the interaction between intracellular lipids and phagocytic macrophages.
ATP-Binding Cassette Transporters/metabolism ; Age Factors ; Animals ; Blood Chemical Analysis ; Cholesterol/metabolism ; Diabetes Mellitus, Type 2/*drug therapy/genetics ; Dyslipidemias/drug therapy/genetics ; Female ; Hyperglycemia/drug therapy/genetics ; Hypoglycemic Agents/*therapeutic use ; Injections, Intraperitoneal ; *Lipid Metabolism/drug effects ; Listeria monocytogenes/*drug effects/immunology ; Listeriosis/*drug therapy/immunology/microbiology ; Macrophages/drug effects/*metabolism ; Mice ; Obesity/drug therapy/genetics ; Peptides/*therapeutic use ; Phagocytosis/drug effects ; Venoms/*therapeutic use