Septicemia in children with leukemia.

A review of the hospital records of 164 children with leukemia diagnosed between January 1969 and December 1975 disclosed 51 episodes of septicemia in 43 patients; 57 infectious agents were isolated. Gram-positive bacteria were isolated as frequently as gram-negative bacteria, each type accounting for 45.6% of all the agents isolated. Only 2 of the 24 episodes of exclusively gram-positive septicemia were fatal, whereas 9 of the 23 episodes of exclusively gram-negative septicemia were fatal. The mean duration of neutropenia was 5.6 days in patients with gram-positive septicemia and 19.5 days in patients with gram-negative septicemia, a significant difference (P less than 0.01). Gram-positive septicemia was diagnosed after a mean of 5.9 days of hospitalization and gram-negative septicemia after a mean of 29.0 days, also a significant difference (P less than 0.001). In this exclusively pediatric population of leukemic patients gram-positive agents have to be considered as potential pathogens, and initial antibiotic therapy must be selected with this fact in mind.     

Gram-negative septicemia in American alligators (Alligator mississippiensis)

Six species of bacteria (family Enterobacteriaceae) not commonly reported as associated with disease in American alligators (Alligator mississippiensis) were documented, suggesting that Aeromonas is not the only bacterium responsible for septicemia in crocodilians. These included Citrobacter freundii, Enterobacter agglomerans, Proteus sp., Morganella morganii, Serratia marcescens, and Klebsiella oxytoca. Clinical signs of disease included intensive basking, anorexia, lethargy, flaccid limb paralysis, stomatitis, and dermatitis. Our data indicated that early treatment with broad-spectrum antibiotics was preferable to waiting for sensitivity results.     

Epidemiology and pathogenesis of Vibrio vulnificus

Vibrio vulnificus is capable of causing severe and often fatal infections in susceptible individuals. It causes two distinct disease syndromes, a primary septicemia and necrotizing wound infections. This review discusses the interaction of environmental conditions, host factors, and bacterial virulence determinants that contribute to the epidemiology and pathogenesis of V. vulnificus.     

Klebsiella pneumoniae as a cause of pneumonia and septicemia in a civet kitten (Civettictis civetta) in the Jos Zoo, Nigeria

A fatal case of acute pneumonia and septicemia that occurred in a captive civet kitten (Civettictis civetta) in the Jos Zoo, Nigeria is reported. Diagnosis was based on clinical signs, necropsy findings, and the isolation of Klebsiella pneumoniae from the lung, intestine, liver and heart blood of the animal. This is the first report of clinical K. pneumoniae infection in a wild or captive animal in Nigeria.     

The syndrome of pneumococcemia,disseminated intravascular coagulation and asplenia.

A 58-year-old man who survived an episode of fulminant pneumococcal septicemia with disseminated intravascular coagulation had undergone splenectomy 23 years previously. In the literature there are 25 reported cases of fulminant septicemia and disseminated intravascular coagulation associated with asplenia in adults (excluding cases in which corticosteroid or immunosuppressive therapy was given). The pneumococcus was responsible for all of these cases as well. The mortality in this series was more than 90%, and death occurred within 24 hours of presentation at hospital in almost 70% of the fatal cases and was associated with high-density bacteremia and adrenal hemorrhage. Gram-staining of the buffy coat of the peripheral blood or the exudate from purpuric skin lesions was carried out in only 6 of the 26 cases but yielded positive results in all but 1. It is concluded that a diagnosis of septicemia in asplenic adults can be established within a short time of presentation on the basis of statistical probability and the results of Gram-staining of the peripheral blood and exudate from the skin lesions. Prevention appears to be the cornerstone of management because of the variable interval from splenectomy to the onset of the syndrome and the high mortality.     

Fatal septicemia due to Clostridium hathewayi and Campylobacter hominis

Clostridium hathewayi and Campylobacter hominis have not been previously reported in infection. We report a fatal case of septicemia, massive intravascular hemolysis, shock, and disseminated intravascular coagulation; both of these organisms were recovered on blood culture, although it seems likely that the C. hathewayi was responsible for the clinical picture and that the C. hominis was an incidental finding.     

Genetic regulation of variable Vi antigen expression in a strain of Citrobacter freundii.

Certain strains of the genus Citrobacter exhibit a variable expression of the Vi surface antigen that appears to involve a special mechanism for regulation of gene expression. Two nonlinked chromosomal loci, viaA and viaB, are known to determine nonvariable Vi antigen expression in strains of Salmonella. To confirm the presence of analogous loci in Citrobacter and to ascertain whether either of them is involved in variable Vi antigen expression in this organism, donor strains were constructed from Citrobacter freundii WR7004 and used to transfer their Vi antigen-determining genes to ViaA- and ViaB- Salmonella typhi recipient strains. Vi antigen expression in C. freundii was found to be controlled by loci analogous to the Salmonella via genes. S. typhi recipients of the C. freundii viaA+ genes were restored to the full, continuous expression of the Vi antigen normally seen in S. typhi. Thus, the C. freundii viaA genes appeared to play no role in the variable expression of the Vi antigen. In contrast, S. typhi recipients of the C. freundii viaB+ genes exhibited the rapid, reversible alternation between full Vi antigen expression and markedly reduced Vi antigen expression that was seen to occur in the C. freundii parent. The C. freundii viaB locus was thus identified as the one whose genes are regulated so as to produce variable Vi antigen expression. Genes determining another C. freundii surface antigen, the synthesis of which is not affected by the mechanism regulating Vi expression, were coinherited with the C. freundii viaB+ genes. An invertible, insertion sequence element located within the C. freundii viaB locus is proposed to account for the regulation of variable Vi antigen expression.     

弗劳地枸橼酸盐杆菌基因种与小儿腹泻关系、耐药性的研究

从１４５７例腹泻患儿大便中分离出１６４株弗劳地枸橼酸盐杆菌复合群的菌株,而对照组中分离率仅４．２６％,具统计学差异。为探讨其致病性,采用不耐热性肠毒素,耐热性肠毒素基因探针,菌液直接ＬＴ－ＰＣＲ,家兔肠袢结扎和刚果红结合试验检测细胞的腹泻毒力因子,证实４７．１％的菌株产生ＬＴ,系腹泻重要毒力因子,不具侵袭性因子。     

Production of methionine γ- lyase in recombinant Citrobacter freundii bearing the hemoglobin gene

The production of antileukemic enzyme methionine γ-lyase (MGL) in distinctly related bacteria, Citrobacter freundii and in their recombinants expressing the Vitresocilla hemoglobin (VHb) has been studied. This study concerns the potential of Citrobacter freundii expressing the Vitreoscilla hemoglobin gene (vgb) for the methionine γ- liyase production. Methionine γ- liyase production by Citrobacter freundii and its vgb(-) and vgb(+) bearing recombinant strain was studied in shake-flasks under 200 rpm agitation, culture medium and 30 °C in a time-course manner. The vgb(+) and especially the carbon type had a dramatic effect on methionine γ- liyase production. The vgb(+) strain of C. freundii had about 2-fold and 3.1-fold higher levels of MGL than the host and vgb(-) strain, respectively.     

Characterization of the Citrobacter freundii phoE gene and development of C. freundii-specific oligonucleotides

The phoE gene of Citrobacter freundii, encoding a pore-forming outer membrane protein, was cloned and its nucleotide sequence was determined. The homologies in terms of identical amino acids between the C. freundii PhoE protein and those of Escherichia coli, E. cloacae and Klebsiella pneumoniae were 90%, 86% and 84%, respectively. Two synthetic oligonucleotides, corresponding to hypervariable, cell surface-exposed regions of the protein, were tested for their specificity in polymerase chain reactions. They were specific for the species C. freundii, i.e., no reaction was detected with 35 non-C. freundii strains tested, including 17 Salmonella, two C. amalonaticus and three C. diversus strains, whereas all five C. freundii strains tested were correctly recognized.     

Cloning of a haemolysin from Citrobacter freundii and its expression in phylogenetically related bacteria

Abstract The determinants for a haemolysin from an extraintestinal isolate of Citrobacter freundii have been cloned and expressed in both Escherichia coli K12 and phylogenetically related bacteria. Compared with E. coli , where the haemolytic determinants are encoded in 7.5 kb, the hemolysin determinants of C. freundii are located on a 2.5-kb Hin dIII fragment in the recombinant plasmid PJP71. Chicken embryo tests indicate that this haemolysin does contribute to the pathogenicity of C. freundii .     

Infectious disease mortality in the USSR

In recent decades infectious and parasitic diseases (class 1 according to the International Classification of Diseases-9) constitute 2-3% of causes in the total morbidity structures in the USSR. The main causes of death among diseases of class 1 are tuberculosis (37%), acute enteric infections (30%), septicemia (11%), viral hepatitides (11%), meningococcal infection (4%), measles (2%). The main groups are children aged up to 2 years (48% of fatal cases of diseases belonging to class 1). The territorial irregularity of mortality indices has been revealed.     

A gene encoding L-methionine gamma-lyase is present in Enterobacteriaceae family genomes: identification and characterization of Citrobacter freundii L-methionine gamma-lyase

Citrobacter freundii cells produce L-methionine gamma-lyase when grown on a medium containing L-methionine. The nucleotide sequence of the hybrid plasmid with a C. freundii EcoRI insert of about 3.0 kbp contained two open reading frames, consisting of 1,194 nucleotides and 1,296 nucleotides, respectively. The first one (denoted megL) encoded L-methionine gamma-lyase. The enzyme was overexpressed in Escherichia coli and purified. The second frame encoded a protein belonging to the family of permeases. Regions of high sequence identity with the 3'-terminal part of the C. freundii megL gene located in the same regions of Salmonella enterica serovar Typhimurium, Shigella flexneri, E. coli, and Citrobacter rodentium genomes were found.     

Type III secretion system cluster 3 is required for maximal virulence of Burkholderia pseudomallei in a hamster infection model

Burkholderia pseudomallei, the etiological agent of melioidosis, is an animal pathogen capable of inducing a highly fatal septicemia. B. pseudomallei possesses three type III secretion system (TTSS) clusters, two of which (TTSS1 and TTSS2) are homologous to the TTSS of the plant pathogen Ralstonia solanacearum, and one (TTSS3) is homologous to the Salmonella SPI-1 mammalian pathogenicity island. We have demonstrated that TTSS3 is required for the full virulence of B. pseudomallei in a hamster model of infection. We have also examined the virulence of B. pseudomallei mutants deficient in several putative TTSS3 effector molecules, and found no significant attenuation of B. pseudomallei virulence in the hamster model.     

Listeria Monocytogenes Infections in Metropolitan Toronto: A Clinicopathological Study

The clinical and laboratory findings in 21 patients with listeriosis are described and the subject is reviewed. Eleven of the infections were septicemias of newborns, eight were meningitis in infants or adults, and two other children had unusual manifestations.Neonatal septicemia was rapidly fatal; one of 11 infants survived. The disease often seemed traceable to mild maternal infection during the third trimester usually leading to premature delivery of critically ill babies. Only awareness of the possible presence of listeriosis and early antibiotic therapy seem capable of reducing this high mortality.Tissues from autopsies showed characteristic microscopic necrotic foci with mononuclear infiltration progressing to microabscesses containing small Gram-positive rods. Lesions were found in the one placenta examined.Five infants with meningitis recovered, and one of three affected adults. Specific diagnosis depends on demonstrating Listeria monocytogenes; differentiation from other forms of acute meningitis cannot be made clinically.One older child had septicemia and another had listerial pharyngitis. Both recovered.     

Proinflammatory cytokine profile in Vibrio vulnificus septicemic patients' sera

Vibrio vulnificus causes a fulminant and frequently fatal septicemia in susceptible hosts. The present study was designed to evaluate the proinflammatory cytokine profile in V. vulnificus septicemia patients' sera and the effect of doxycycline therapy on the levels of proinflammatory cytokines. Levels of proinflammatory cytokines, tumor necrosis factor (TNF)-alpha, interleukin (IL)-1beta and IL-6, were measured in the sera of V. vulnificus septicemic patients and normal healthy volunteers using colorimetric sandwich ELISA. The mean values of TNF-alpha, IL-1beta and IL-6 in the sera of V. vulnificus patients (n=33) increased by 210-, 232- and 40-fold in comparison with those of normal healthy volunteers (n=5), but only the IL-6 level showed a statistically significant difference (P<0.05) between the two groups. Sera from the cases for which doxycycline treatment histories were obvious were designated 'before-treatment' (TX). All the others were included in the after-TX group. In the before-TX group (n=5), the levels of TNF-alpha and IL-1beta significantly increased (P<0.05) in comparison with the after-TX group (n=5). IL-6 levels in the two groups showed no difference. In conclusion, the levels of the well known proinflammatory cytokines TNF-alpha, IL-1beta and IL-6 increased in the V. vulnificus septicemic patients' sera, and the levels of TNF-alpha and IL-1beta decreased significantly after doxycycline treatment. These data indicate that proinflammatory cytokines might play a critical role in V. vulnificus septicemia like in other endotoxemic shocks. The use of doxycycline as an effective bactericidal agent and as an effective modulator of proinflammatory cytokines is supported.     

一株弗劳地枸橼酸杆菌中检出新ampC基因

目的探讨1株耐亚胺培南弗劳地枸橼酸杆菌的耐药机制。方法采用浓度梯度法（Etest）检测对抗菌药物的最低抑菌浓度（MIC）。通过金属酶初筛试验（协同法）检测金属酶;改良Hoged试验检测碳青霉烯酶;头孢西丁三维试验检测AmpC酶;聚合酶链反应（PCR）检测耐药基因;DNA测序决定基因型;接合试验检测耐药基因的转移性。结果弗劳地枸橼酸杆菌临床分离株NC118对亚胺培南的MIC为〉16μg/ml,金属酶初筛试验阴性,Hoged表型确证试验碳青霉烯酶阳性,AmpC酶阳性,PCR扩增及测序显示含有blaKPC-2、blaAmpC基因,该菌株所产AmpC酶基因与CMY-45型AmpC酶（GenBank：ACU00152.1）比较有5个氨基酸发生了改变,该blaCMY-2-like基因为一个新型的AmpC酶基因。结论在弗劳地枸橼酸杆菌中发现一种新的ampC基因（blaCMY-49）。     

Protective effect of polygoni cuspidati radix and emodin on <Emphasis Type="Italic">Vibrio vulnificus</Emphasis> cytotoxicity and infection

Vibrio vulnificus, a good model organism of bacterial septicemia, causes fatal septicemia manifesting a fulminating course and a high mortality rate within days. In order to identify new natural substances preventing V. vulnificus infection, a plant library was screened for inhibiting cytotoxicity to host cells by using Trypan blue staining and LDH assay. We found that Polygoni Cuspidati Radix potently suppressed the acute death of HeLa and RAW264.7 cells in a dose dependent manner. Further studies revealed that Polygoni Cuspidati Radix inhibited V. vulnificus growth and survival in HI broth and seawater, respectively. We confirmed that Polygoni Cuspidati Radix contained high level of emodin by thin layer chromatography (TLC). Emodin showed direct antibacterial activity against V. vulnificus. In addition, emodin prevented the morphologic damages and acute death of HeLa cells caused from V. vulnificus. The safety of Polygoni Cuspidati Radix and emodin to host cells was confirmed by MTT assay. Polygoni Cuspidati Radix and emodin protected mice from V. vulnificus infection.     

Inactivation of the ampD gene causes semiconstitutive overproduction of the inducible Citrobacter freundii beta-lactamase.

In Citrobacter freundii and Enterobacter cloacae, synthesis of AmpC beta-lactamase is inducible by the addition of beta-lactams to the growth medium. Spontaneous mutants that constitutively overproduce the enzyme occur at a high frequency. When the C. freundii ampC beta-lactamase gene is cloned into Escherichia coli together with the regulatory gene ampR, beta-lactamase expression from the clone is inducible. Spontaneous cefotaxime-resistant mutants were selected from an E. coli strain carrying the cloned C. freundii ampC and ampR genes on a plasmid. Virtually all isolates had chromosomal mutations leading to semiconstitutive overproduction of beta-lactamase. The mutation ampD2 in one such mutant was caused by an IS1 insertion into the hitherto unknown ampD gene, located between nadC and aroP at minute 2.4 on the E. coli chromosome. The wild-type ampD allele cloned on a plasmid could fully trans-complement beta-lactamase-overproducing mutants of both E. coli and C. freundii, restoring the wild-type phenotype of highly inducible enzyme synthesis. This indicates that these E. coli and C. freundii mutants have their lesions in ampD. We hypothesize that induction of beta-lactamase synthesis is caused by blocking of the AmpD function by the beta-lactam inducer and that this leads directly or indirectly to an AmpR-mediated stimulation of ampC expression.     

L-methionine γ-lyase from Citrobacter freundii: Cloning of the gene and kinetic parameters of the enzyme

It is shown for the first time for the Enterobacteriaceae family that a gene encoding L-methionine gamma-lyase (MGL) is present in the genome of Citrobacter freundii. Homogeneous enzyme has been purified from C. freundii cells and its N-terminal sequence has been determined. The hybrid plasmid pUCmgl obtained from the C. freundii genomic library contains an EcoRI insert of about 3000 bp, which ensures the appearance of MGL activity when expressed in Escherichia coli TG1 cells. The nucleotide sequence of the EcoRI fragment contains two open reading frames. The first frame (the megL gene) encodes a protein of 398 amino acid residues that has sequence homology with MGLs from different sources. The second frame encodes a protein with sequence homology with proteins belonging to the family of permeases. To overexpress the megL gene it was cloned into pET-15b vector. Recombinant enzyme has been purified and its kinetic parameters have been determined. It is demonstrated that a presence of a hybrid plasmid pUCmgl, containing the megL gene in the E. coli K12 cells, leads to a decrease in efficiency of EcoKI-restriction. It seems likely that decomposition of L-methionine under the action of MGL leads to a decrease in the intracellular content of S-adenosylmethionine. Expression of the megL gene in the C. freundii genome occurs only upon induction by a significant amount of L-methionine.