Elevated levels of tumor necrosis factor-alpha (TNF-alpha) and interleukin-6 (IL-6) activities in the sera and milk of cows with naturally occurring coliform mastitis

The presence of tumor necrosis factor-alpha (TNF-alpha) and interleukin-6 (IL-6) activities was determined in milk and serum of cows with naturally occurring coliform mastitis (CFM). TNF-alpha was detected in the sera from 26 of 32 cows with CFM. TNF-alpha levels were higher in the sera than in the milk. IL-6 was high in the sera of surviving CFM animals, but was low in animals that died and in healthy controls. Furthermore, the mean level of IL-6 was 20-fold higher in the milk than in the sera of mastitic cows. The level of IL-6 in the serum was correlated to that in the milk in individual animals. The presence of IL-6 and TNF-alpha in the sera appears to relate to severe clinical condition of CFM, in the milk whereas they may play a role in generating inflammation of the mammary gland.

Differential distributions in tissues and efficacies of aztreonam and ceftazidime and in vivo bacterial morphological changes following treatment

The differential tissue distributions of aztreonam and ceftazidime within fibrin clots infected with Pseudomonas aeruginosa, Enterobacter cloacae, and Serratia marcescens, their efficacies, and the in vivo bacterial morphological changes induced by these drugs were evaluated. Rabbits were given intravenously a single dose of 100 mg of either agents/kg of body weight. In the cores of the clots, the peak levels of both drugs were much lower than those observed in the peripheries and in serum. Aztreonam's half-lives within the peripheries and in the cores of the fibrin clots were up to six times higher than observed in serum, while ceftazidime's half-lives in clots were twice that observed in serum. This resulted in a much greater penetration ratio for aztreonam than for ceftazidime. Both drugs controlled the growth of P. aeruginosa in vivo, but E. cloacae and S. marcescens responded better to ceftazidime. Morphological changes were more abundant in the peripheries than in the cores of the clots. In the control group, P. aeruginosa's morphology in the cores was different than that in the peripheries of the clots. Against P. aeruginosa, aztreonam did induce morphological changes in the cores while ceftazidime did not. Electron microscopic studies revealed that morphological changes associated with aztreonam seemed different than those of ceftazidime. Along with elongation of bacteria, more bow tie and herniated bacteria were observed with aztreonam. Though both agents selectively affect PBP 3, as manifested by elongated bacteria, they induce in the peripheries of the clots thickening, breaks, and detachment in bacterial cell walls, alterations which are generally associated with antibiotics affecting PBP 1a and 1b.

Equine herpesvirus type 2: prevalence and seroepidemiology in foals

Whole blood and serum were collected from foals to determine the prevalence of Equine herpesvirus type 2 (EHV 2) infection in foals, age at which infection can first be identified and serological responses to infection. Equine herpesvirus type 2 was isolated from peripheral blood mononuclear cells (PBMC) from 68 of 69 foals, 1-8-months-old, sampled once. Virus isolation was performed twice at intervals of 2-7 months on PBMCs from 33 foals and EHV2 was isolated on both occasions in all but one foal (negative, then positive). Regression analysis of log2-transformed reciprocal serum EHV2 virus neutralising (VN) titres revealed that in foals age 1-7 months, EHV2 VN antibody titre was positively correlated with age (r = 0.94). Paired serum samples were obtained from 58 foals, with the first samples collected age 1-6 months and the second samples collected 2-4 months later. There were significant (P < 0.05) increases in mean VN titres to EHV2 in foals sampled initially at age 1-4. Eight foals had blood sampled prior to sucking and at age 7, 20, 30 and 45 days. Each foal was negative for EHV2 in PBMC and each foal had a negative serum EHV2 VN titre immediately after birth. Each foal was positive for EHV2 in PBMC by age 45 days, with the earliest isolation at 25 days. Tracheal aspirate fluid and peripheral blood were collected from 20 foals without clinical signs of respiratory disease and from 30 foals with clinical signs of lower respiratory disease. In 20 foals without clinical signs of respiratory disease, EHV2 was isolated from tracheal aspirates (1/20 foals) and PBMC (20/20 foals) and in 30 foals with such clinical signs, from trachea aspirates (20/30 foals: P < 0.01) and from PBMC (30/30 foals). In one 6-month-old foal, EHV1, but not EHV2, was isolated from the tracheal aspirate, 3 months after EHV2 had been isolated from a tracheal aspirate. These results demonstrate a greater prevalence of EHV2 in lower respiratory secretions in foals with clinically apparent lower respiratory disease, but a cause and effect relationship between the virus and lower respiratory disease remains to be elucidated. It is noteworthy, however, that of virus isolations performed on 50 tracheal aspirates, a virus (EHV1) other than EHV2 was isolated only once.

Concordance of endotoxemia with gram-negative bacteremia in patients with gram-negative sepsis: a meta-analysis

The Limulus amebocyte lysate (LAL) assay is a sensitive method for detecting endotoxin. Using gram-negative (GN) bacteremia as the basis for comparison, concordance with endotoxemia in 45 studies could be expressed as an odds ratio. Calculation of summary odds ratios by the Mantel-Haenszel-Peto method indicated that the concordance of the results was no higher by the chromogenic LAL assay than by the gelation version, and the sensitivity was improved by only 11% (62 versus 51%). Endotoxemia was detected in 77 (68%) of 114 patients with bacteremia caused by an organism that was not a member of the family Enterobacteriaceae, whereas endotoxemia was detected in only 120 (45%) of 269 patients with bacteremia caused by a member of the family Enterobacteriaceae or an anaerobe (P < 0.001). This difference was also apparent for patients with GN bacteremia for whom a fatal outcome had been recorded. The prevalence of GN bacteremia in the tested population and the type of etiological agent are critical and previously unrecognized variables which affect the interpretation of the LAL test in patients with suspected sepsis.

Novel automated microbial screening of platelet concentrates

The recovery of bacteria and the speed of detection of microbial growth in platelet concentrates (PC) were studied, comparing a novel automated blood culture system (BacT/Alert) with two traditional methods. Full-scale experiments were performed with a total of 33 units of PC (average content 320 x 10(9) platelets per unit) obtained from pooled buffy coats. Six strains known as possible PC contaminants were tested: S. epidermidis, S. aureus, P. aeruginosa, B. cereus, E. aerogenes, and S. sanguis. Using an inoculum of 50-98 bacteria/ml, bacterial contamination was detected in all of 11 PCs on 132 sampling occasions. With a small inoculum (0.3-9 bacteria/ml), the bacterial contamination was detected in all PCs in which abundant growth appeared, but failed to be detected in some instances where the bacterial content was very small. All of 11 uninoculated PC controls were negative. With the automated method the time for detection of a culture-positive PC was 6-16 h, clearly shorter than with the two manual-visual systems. The new system provides a rapid, reliable, and labour-saving method for screening of bacterial contamination in PCs. This would increase safety particularly if the present 5-day shelf life were extended.

Female genital tract abscess formation in the rat. Use of pathogens including enterococci

Previous animal experiments utilizing bowel flora have demonstrated synergy between various aerobes and anaerobes in the formation of intraabdominal abscesses. In these experiments, human female genital tract isolates were inserted into the abdominal and pelvic cavities of 151 female Sprague-Dawley rats. Inoculation with any single species of organism--Streptococcus faecalis, Enterobacter cloacae or Bacteroides bivius or a combination of two facultative organisms (S faecalis plus E cloacae)--did not result in a significant increase in abscess formation. Combination of a facultative organism or organisms with the anaerobe B bivius or S faecalis plus B bivius plus E cloacae resulted in 55% (P < .01) and 74% (P < .0005) rates of abscess formation, respectively, as compared with controls. Combinations including B fragilis demonstrated similar results. Thus, female genital tract facultative organisms demonstrate synergy in the presence of anaerobic organisms in the development of abscesses.

Multicenter clinical evaluation of a continuous monitoring blood culture system using fluorescent-sensor technology (BACTEC 9240)

The BACTEC 9240 (Becton Dickinson Diagnostic Instrument Systems, Sparks, Md.) is a new continuous-monitoring blood culture system that uses internal, fluorescent-CO2 sensors. In a multicenter clinical trial, organism yield and times to detection with the prototype BACTEC 9240 system were compared with those of the BACTEC NR 660 system. Equal volumes of blood were inoculated into the bottles included in the study blood culture sets (aerobic and anaerobic 9240 and NR6A and NR7A bottles). A total of 9,391 aerobic and 8,951 anaerobic bottle pairs were inoculated with 9,801 blood specimens. A total of 587 clinically significant positive blood cultures and 415 cases of sepsis were studied. The standard 9240 aerobic bottle detected significantly more Staphylococcus aureus (P < 0.05), coagulase-negative staphylococci (P < 0.01), and total microorganisms (P < 0.001) than the NR6A bottle. The standard 9240 anaerobic bottle detected significantly more coagulase-negative staphylococci (P < 0.001), members of the family Enterobacteriaceae (P < 0.01), and total microorganisms (P < 0.001) than the NR7A bottle. A total of 420 positive cultures were detected in both systems; for 284, the time to detection was equivalent with both systems (within 12 h); for 123, the 9240 system was faster; and for 13, the NR 660 system was faster (P < 0.001). The average times to detection for the 9240 and the NR 660 systems were 20.2 and 27.5 h, respectively. Ninety-nine cultures were positive only in the 9240 system, and 68 cultures were positive only in the NR 660 system (P < 0.02). The 9240 system also detected significantly more episodes of bacteremia (P < 0.001). The false-positive rates for the 9240 and NR 660 systems were 2.2 and 2.3%, respectively. The false-negative rates for the two systems after 5 days of incubation did not differ significantly. The contamination rates for the 9240 and NR 660 systems were 1.9 and 1.5%, respectively (P < 0.05). In conclusion, the prototype 9240 system detected more clinically significant positive blood cultures and did so sooner than the NR 660 system, with the additional advantages of full automation, continuous monitoring, and noninvasive sampling.

Use of ciprofloxacin in an infant with ventriculitis

Ciprofloxacin was used successfully in a neonate with ventriculitis caused by a multiply resistant strain of Enterobacter cloacae. Limited pharmacokinetic data indicated that adequate concentrations of drug could be attained in cerebrospinal fluid.

Interleukin-6 (IL-6) and acute-phase proteins in rats with biliary sepsis

We measured serum interleukin-6 (IL-6) and acute-phase proteins, alpha 1-acid glycoprotein (AGP) and alpha 2-macroglobulin (alpha 2M), after a retrograde intrabiliary bacterial infection in rats with biliary obstruction. Maximum serum IL-6 was obtained at 6 h in rats following inoculation of bacteria (10(6) CFU/ml E. Coli) in the bile duct and it was higher than that observed in rats undergoing a bile duct ligation or a laparotomy. There was a strict relationship between the level of IL-6 at 6 h and the modified levels of AGP and alpha 2M at 48 h. AGP and alpha 2M levels were the highest in sera of rats with bile duct infection as compared with those found in sera of rats with bile duct ligation or laparotomy. After inoculation of E. Coli or E. Fecalis, blood IL-6 level was always higher at 6 h in inferior vena cava as compared with that found in the supra hepatic vein. These results indicate that IL-6 is synthesized after a biliary sepsis and that its blood level is higher in the systemic circulation than in the local circulation.

[Evaluation of the risk of exposure to unfavorable environmental based on the results of sanitary, microbiological and clinical studies]

It has been established as result of studies with the use of complex sanitary-hygienic, microbiological, clinical and statistical methods, that the increasing antropogenic stress causes changes in microbiocenosis of water objects of the environment and of blood serum, which may produce unfavourable human health effects. The necessity to use integral complex indexes of the state of man and water medium for the assessment of the degree of risk of ++eco-technogenic effects has been found out.

Enterobacter hormaechei, a new species of the family Enterobacteriaceae formerly known as enteric group 75

The name Enterobacter hormaechei is proposed for a new species of the family Enterobacteriaceae, formerly called Enteric Group 75, which consists of 23 strains, 22 of which were isolated from humans. DNAs from 12 E. hormaechei strains tested were highly related to the type strain (ATCC 49162) by DNA hybridization, using the hydroxyapatite method (80 to 97% in 60 degrees C reactions; 80 to 90% in 75 degrees C reactions). The strains were most closely related (50 to 63%) to Enterobacter cloacae, Enterobacter dissolvens, Enterobacter taylorae, and Enterobacter nimipressuralis. E. hormaechei strains were positive within 48 h for the following: Voges-Proskauer test; citrate utilization (Simmons and Christensen); urea hydrolysis (87%); ornithine decarboxylase; growth in potassium cyanide (KCN); malonate utilization; production of acid from D-glucose, L-arabinose, cellobiose, dulcitol (87%), D-galactose, maltose, D-mannitol, D-mannose, L-rhamnose, sucrose, trehalose, and D-xylose; acid production from mucate; nitrate reduction; and o-nitrophenyl-beta-D-galactopyranoside. Delayed positive reactions were seen in tests for arginine dihydrolase, gas from D-glucose, acid from alpha-methyl-D-glucoside, and acetate utilization. E. hormaechei was negative in tests for indole production; H2S production; phenylalanine deaminase; lysine decarboxylase; gelatin hydrolysis; acid production from D-adonitol, D-arabitol, erythritol, glycerol, i(myo)-inositol, melibiose, raffinose, and D-sorbitol; esculin hydrolysis; DNase; lipase; and tyrosine clearing. Variable reactions occurred in tests for methyl red, motility, and tartrate. All strains tested were susceptible or moderately susceptible to amikacin, azlocillin, cefotaxime, ceftazidime, ceftriaxone, chloramphenicol, gentamicin, mezlocillin, moxalactam, piperacillin, trimethoprim-sulfamethoxazole, sulfisoxazole, thienamycin, tobramycin, and trimethoprim. All strains tested were resistant to nitrofurantoin; the majority were resistant to ampicillin, cefoxitin, and cephalothin. Four isolates were from blood; most other isolates were from wounds or sputum.

Anti-K1 of the IgA class associated with Morganella morganii infection

An anti-K1 alloantibody developed in a patient infected with Morganella morganii. The serologic behavior and response to dithiothreitol initially suggested that the alloantibody was an IgM. However, flow cytometry and the separation of immunoglobulin classes by serum chromatography revealed that the anti-K1 was constituted solely of IgA. These data suggest that bacteria-induced red cell antibodies might be of the IgA class.

[Clinical and pharmacokinetic study of imipenem/cilastatin in children and newborn infants]

Imipenem, a new carbapenem (thienamycin) beta lactam antibiotic which is clinically used in a 1:1 combination with cilastatin, an inhibitor or renal metabolism of imipenem, was evaluated in 25 patients; 11 children and 14 neonates. A mean daily dose of 60 mg/kg was given to children and the dose in neonates was 50 mg/kg. Clinically, 21 patients were cured, two failed to respond to treatment and two were not evaluable. Pharmacokinetic studies were performed in the 11 children and in 10 of the neonates. The mean elimination half-life of imipenem was 0.87 h in children and 2.1 h in neonates. The mean cilastatin elimination half-life was 0.73 h in children and 5.1 h in neonates. This difference in half-life between children and neonates is similar to the one noted between healthy adults and adults with renal insufficiency. No accumulation of imipenem was seen in neonates studied on the first and fifth days of treatment.

Acute interstitial nephritis following enterobacteriaceae sepsis

A 52-year-old male developed acute renal failure (ARF) following enterobacteriaceae sepsis. The cause of renal failure was remarkable for prolonged, slow, and incomplete recovery. Recurrence of enterobacteriaceae infection was associated with fever, cutaneous rash, eosinophilia, and elevated IgE level. Renal biopsy and gallium scan studies confirmed the diagnosis of acute interstitial nephritis. The temporal relationship between the first episode of sepsis and the precipitation of ARF and the development of rash, eosinophilia, and elevated IgE level in association with recurrence of infection indicated the role of bacterial antigen in the induction of immune-mediated injury.

Influence of imipenem on the serum resistance of enterobacteriaceae

Following growth in a subinhibitory concentration of imipenem and additional incubation in a 20% dilution of normal human serum (NHS) for 90 minutes, five of 12 serum-resistant strains of enterobacteriaceae showed a decrease in colony-forming units of two or more logs of growth compared with the control. Two strains (of Escherichia coli and Enterobacter aerogenes) showed this phenomenon even with incubation in 5% NHS. Treatment with imipenem did not change the serum resistance of the other seven strains (two strains each of Enterobacter cloacae, Klebsiella pneumonia, and Serratia marcescens, and one strain of Proteus morganii). The phenomenon of induced serum susceptibility is dose dependent and reversible. Other beta-lactam antibiotics either caused only a slight decrease of resistance (cefsulodin, cefoxitin, cefuroxime, cefodizime-HR221) or did not influence the serum resistance at all (cefotaxime, mecillinam). Killing of the induced serum-sensitive strains appeared to be antibody dependent.

An outbreak of pseudobacteremia caused by Enterobacter cloacae from a phlebotomist's vial of thrombin

In a 15-day period, seven patients in a small hospital each had one blood culture positive for Enterobacter cloacae. None of the seven patients was septic. All seven positive culture specimens had been obtained by phlebotomist A, who also had obtained 13 negative culture specimens in the same period. Seven other phlebotomists had drawn 69 blood samples for culture during the same period; none had yielded any microorganism (p = 0.00001). Vials of thrombin, routinely used to coagulate blood specimens for chemical analysis, had been carried on the phlebotomy trays. We observed that phlebotomist A occasionally spilled drops of the viscous thrombin on her finger during the procedures. Culture of the thrombin on her tray yielded E. cloacae. No further cases of E. cloacae bacteremia occurred after she stopped drawing blood for culture and the thrombin on her tray was removed from use.

Protective effect of polymyxin B sulfate in experimental enterobacterial infection in mice

The mouse model of intraperitoneal enterobacterial sepsis was used to evaluate the anti-endotoxic effect of polymyxin B sulfate. Single or multiple therapeutic doses of polymyxin, administered either before or after lethal challenge with Serratia marcescens, produced statistically and clinically significant protective effects.

Antibiotic concentrations in ascitic fluid of patients with ascites and bacterial peritonitis

Thirty-six paired specimens of serum and ascitic fluid from 21 patients with peritonitis and ascites, most with sponetaneous bacterial peritonitis and alcoholic cirrhosis, were assayed for antibiotic content. Antibiotics assayed and number of determinations were gentamicin, 14; tobramycin, 7; ampicillin, 5; clindamycin, 3; penicillin G, 2; cephalothin, 2; chloramphenico, 2; and cefazolin, 1. In 31 pared specimens the ascitic fluid antibiotic concentration was about one half or more of the simultaneous serum level and in 17 assays exceeded 90% of the serum level. All antibiotics studied penetrated ascitic fluid equally well. Clinical response to antibiotic therapy was good in 12 of 16 patients with culture-proven bacterial peritonitis. Antibiotic levels in ascitic fluid exceeded the minimal inhibitory concentration of the infecting organisms in all but one patient who responded. Direct intraperitoneal instillation of antibiotics does not appear to be necessary routinely; however, there may be an initial lag of several hours before antibiotic concentrations is ascites achieve therapeutic levels.

Bacteraemia in a London teaching hospital 1966-75

Analysis of blood-cultures done at St. Bartholomew's Hospital over the decade 1966-75 has revealed a five-fold increase in the incidence of bacteraemia. This increase was particularly prominent in patients with non-malignant disease. The predominance of bacteraemia caused by gram-negative organisms declined in recent years, whereas bacteraemia due to gram-positive organisms, anaerobes, and Candida spp. increased. A recent increase in the number of blood-cultures performed was associated with the introduction of commercially prepared bottles. This led to a higher rate of investigation of patients who ultimately proved to have negative results, and also to a higher incidence of contamination which exceeded the positivity-rate.

Impaired glucose flow in burned patients with gram-negative sepsis

Fifteen thermally injured patients with positive blood stream cultures for gram-negative organisms demonstrated a decreased mass flow of glucose through the glucose space when compared with 17 patients without sepsis studied at a comparable time after injury. Amino acid concentrations determined in ten burned patients with sepsis and nine burned patients without sepsis revealed an increase in the gluconeogenic precursors alanine, glycine, methionine and phenylalanine in those patients with sepsis. The administration of alanine consistently increased serum glucose in seven patients without sepsis but exerted no effect on glucose concentrations in six person with sepsis. These data, taken together, indicate that gram-negative sepsis in burned patients impairs the increased rate of glucose production and flow to peripheral tissue which characteristically occurs after thermal injury.

Amikacin for treatment of infections in patients with malignant diseases

Amikacin was evaluated in patients with malignant diseases during 134 episodes of identified infection, most of which were cases of pneumonia and septicemia. The overall rate of response of the identified infections was 63%. The majority of infections were caused by Escherichia coli, the Klebsiella-Enterobacter-Serratia group, and Pseudomonas aeruginosa. The response rate for infections caused by these organisms was 80%. Five of eight infections caused by organisms resistant to gentamicin responded to therapy with amikacin. Nephrotoxicity was observed in 13% of patients who had normal renal function initially.

Clinical and laboratory studies with amikacin in newborns, infants, and children

Thirty (86%) of 35 infants and older children with proven gram-negative sepsis had a complete clinical remission after treatment with amikacin. In 27 (82%) of 33 infectious episodes for which bacteriologic results were available before and after treatment, the organism was eradicated. The dosage of amikacin was either 7.5 mg/kg or 15 mg/kg given intramuscularly at 12-hr intervals. No adverse clinical effects or laboratory abnormalities were observed during treatment, which lasted from five to 14 days. All bacteria were sensitive to amikacin when tested by the disk diffusion method, and all but a single strain of Pseudomonas were sensitive when tested by the agar dilution method. Assays of serum and urine demonstrated adequate levels of amikacin after single intramuscular injections of 3.75 or 7.5 mg/kg; simultaneous assays of serum and cerebrospinal fluid in two cases demonstrated comparable concentrations of drug suggestive of a high degree of penetration into the cerebrospinal fluid in two cases demonstrated comparable concentrations of drug suggestive of a high degree of penetration into the cerebrospinal fluid during infection. Serial measurements of amikacin in serum from 0.5 to 12 hr after administration of single doses of 7.5 mg of drug/kg to six newborns revealed no significant differences in the concentrations achieved with intramuscular or intravenous administration of the drug.

Amikacin therapy for severe gram-negative sepsis: efficacy in infections involving gentamicin-resistant organisms

Thirty-eight patients with 41 serious infections due to gram-negative bacteria were treated with amikacin. Twenty of these infections involved organisms that were resistant to gentamicin. The results of therapy in 31 of the infections satisfied the criteria for bacteriologic and clinical cure. Eight patients with urinary tract infections and obstructive uropathy had a good clinical response, but routine follow-up cultures of urine at 30 days were positive. Two patients had persistent sepsis and were considered therapeutic failures. Toxicity to the eighth nerve was documented in three of 31 patients for whom routine audiometric testing was performed. These results indicate that amikacin is effective in the treatment of serious infections due to gram-negative bacilli and is particularly useful in infections involving resistant organisms.

Comparative effectiveness of combinations of amikacin with penicillin G and amikacin with carbenicillin in gram-negative septicemia: double-blind clinical trial

Preliminary results are presented for an ongoing, double-blind, clinical trial, in which the efficacy of amikacin plus penicillin G (Amik-Pen) and amikacin plus carbenicillin (Amik-Carb) is compared in treatment of severe gram-negative infections superimposed on serious underlying disease. All clinical isolates were sensitive to amikacin in vitro (minimal inhibitory concentration, less than 12 mug/ml). Results in 50 patients with cancer and documented gram-negative infection, 29 of which involved septicemia, were analyzed. In the Amik-Pen group, 40% of 15 cases of septicemia responded favorable to therapy, as compared with 86% of 14 cases of septicemia in the Amik-Carb group; this difference is statistically significant (P less than 0.02). When all patients were considered together, the outcome appeared more favorable (1) in infections caused by pathogens sensitive to both antibiotics used then in those caused by organisms sensitive to amikacin only (83% vs. 43%); (2) when the combined antibiotics demonstrated synergy in virto against the offending pathogen than when the combination was nonsynergistic (83% vs. 38%); and (3) when the peak serum antimicrobial dilution titer was larger than or equal to 1:8 than when titers were lower. The results of this study suggest that routine use of an antibiotic combination that has demonstrable in vitro synergy against the offending pathogen should be considered for the treatment of proven or suspected severe infections due to gram-negative bacilli.

Host resistance to Serratia marcescens infection: serum bactericidal activity and phagocytosis by normal blood leukocytes

Serratia marcescens strains isolated from clinical specimens can be divided into those which are sensitive or resistant to the bactericidal activity of normal human serum. Serum bactericidal activity is heat labile, cation dependent, and is absorbable by whole, serum-sensitive Serratia or ethanol-insoluble extracts of these organisms. Bacteremic Serratia infection is invariably caused by the serum-resistant strains. Serum resistant Serratia are ingested and killed by normal human leukocytes and fresh normal serum. Heating or preabsorption of serum with whole, heat-killed, or ethanol-insoluble antigen extracts of the serum-resistant Serratia diminishes opsonization and phagocytosis. Serratia opsonins in the serum of healthy individuals are type-specific IgM globulins which combine with the organism and activate complement by the alternate pathway.

Amikacin therapy of infections in neutropenic patients

Amikacin, a new aminoglycoside antibiotic, was utilized in the treatment of 49 cases of infection which occurred in 39 neutropenic cancer patients. Thirty-four patients (69 per cent) responded to this antibiotic. Pneumonia and septicemia were the most common types of infection treated and the response rates were 65 per cent and 75 per cent, respectively. Gram-negative bacili were responsible for 93 per cent of the identified infections and 74 per cent responded. E. coli, Ps. aeruginosa, and organisms of the Klebsiella-Enterobacter-Serratia group were the most common gram-negative bacilli causing infection. Responses were more frequent among patients who maintained higher serum concentrations of antibiotic, but the differences were not statistically significant. Patients with severe neutropenia (less than 100 neutrophils/mm3) had a response rate of 68 per cent. Toxicity was manifested as azotemia and hearing loss which occurred in 13 per cent and 6 per cent, respectively. However, toxicity was directly related to serum concentration and to the number of treatments with amikacin. This antibiotic is of potential importance because of its efficacy against gram-negative bacilli infections. Best results were obtained when sufficient drug was given as a continuous intravenous infusion to maintain serum concentrations of about 15 mu g/ml.

Amikacin therapy for severe gram-negative sepsis. Emphasis on infections with gentamicin-resistant organisms

Amikacin (BB-K8) is a semisynthetic derivative of kanamycin which is active in vitro against many gentamicin-resistant Gram-negative bacilli. Twenty-three patients with 25 serious Gram-negative infections were treated with this new aminoglycoside. Twelve infections involved organisms that were resistant to gentamicin. Twenty patients satisfied the criteria for bacteriological and clinical cure. This included 11 of the 12 infections involving gentamicin-resistant Gram-negative bacilli. In 4 urinary tract infections there was a good clinical response, but routine follow-up urine cultures at 30 days were positive. One patient failed on amikacin therapy. Eighth nerve toxicity was detected in two patients. These results indicate that amikacin is effective in the treatment of serious Gram-negative infections and is particularly useful in those involving resistant organisms. Further studies are indicated to evaluate ototoxic potential.

Chronic polymicrobial bacteremia

A 13-year-old girl had chronic polymicrobial bacteremia with Enterobacter hafnia and Enterobacter agglomerans in the absence of any demonstrable underlying illness, use of immunosuppressive drugs, or discovery of portal of entry of the bacteria. She was treated successfully with a prolonged course of carbenicillin and aminoglycoside antibiotics which were tolerated well. The only side effect of the therapy was a transient episode of vestibular dysfunction which was reversible following cessation of gentamicin. The principles of management of polymicrobial bacteremia are presented.

Penetration of parenterally administered gentamicin into the cerebrospinal fluid in experimental meningitis

The penetration of parenterally administered gentamicin into the CSF was examined in dogs. The experiments were carried out in three stages: (1) in healthy dogs, (2) in dogs with meningitis, and (3) during recovery from the acute inflammation. Gentamicin was found to penetrate poorly into the CSF, reaching mean peak levels of 0.7 mug/ml in healthy dogs. During the height of the meningeal inflammation the mean peak gentamicin level in the CSF was 0.9 mug/ml. The ratio of mean maximum CSF to mean maximum serum levels of gentamicin was 5.8% in healthy dogs, and 11.3% in dogs with meningitis. Thus, inflammation increases the penetration of parenterally administered gentamicin into the CSF, but therapeutically adequate levels for gram-negative bacillary meningitis are not achieved.

Coliform bacteraemia in infants

The incidence of patients with positive blood cultures from which a single species of coliform bacillus was isolated is given for the years 1962 to 67. There has been an increase during these years particularly in neonatal infants: 91 cases were recorded in babies under 6 months of age, and the bacteriological and clinical findings have been related in 85. Children born either prematurely or as a multiple birth and those with congenital malformations showed a predisposition to this form of infection. Many of the remaining cases had an associated localised infection.

Some aspects of the cause of the increase in coliform bacteraemia in babies are discussed and the severity and possible implications of the infection are emphasised.