Sensitive and specific phenotypic assay for metallo-beta-lactamase detection in Enterobacteria by use of a moxalactam disk supplemented with EDTA.

Moxalactam is highly hydrolyzed by plasmid-mediated metallo-ß-lactamases (MBLs), whereas it is poorly inactivated by serine-active carbapenemases. This study demonstrated that moxalactam resistance constituted an effective screen for MBL expression in enterobacteria, which could be confirmed, even in low-MBL-producing isolates, by a disk potentiation test using moxalactam and EDTA.

Lysis-deficient bacteriophage therapy decreases endotoxin and inflammatory mediator release and improves survival in a murine peritonitis model.

BACKGROUND: Lysis-deficient (LyD) bacteriophages (phages) kill bacteria without endotoxin (Et) release. This may minimize systemic cytokine responses and limit inflammation in bacterial sepsis. We determined the effects of t amber A3 T4 LyD and virulent wild-type (WT) phages on mouse bacterial peritonitis. METHODS: Balb/c mice were injected with B40sul Escherichia coli, treated intraperitoneally with LyD, WT, or a beta-lactam antibiotic [latamoxef sodium (LMOX)], and followed for survival. We measured Et release, tumor necrosis factor (TNF)-alpha and interleukin (IL)-6, as well as bacterial counts and peritoneal exudative cells (PECs) in peritoneal lavage fluid at 6 and 12 hours after infection. RESULTS: LyD mice showed significantly greater survival compared with other groups. Et levels were significantly lower in the LyD mice at 6 and 12 hours after infection. TNF-alpha and IL-6 levels were lower in LyD mice compared with control (untreated) mice at 12 hours. Compared with controls, bacteria counts in peritoneal lavage fluid were lower in all treatment groups (LyD, WT, or LMOX) at 6 and 12 hours. PEC counts were highest in LyD mice at 6 hours but significantly lower than that in WT phage- and LMOX-treated mice at 12 hours. CONCLUSIONS: LyD phage therapy significantly improves survival and attenuates the systemic effects of bacterial sepsis by minimizing Et release and pro-inflammatory mediators in murine bacterial peritonitis. Further studies may find phage therapy useful in treating peritonitis and multidrug-resistant bacterial infections.

Improvement of the rectal bioavailability of latamoxef sodium by adjuvants following administration of a suppository.

The absorption of an antibiotic, latamoxef sodium (LMOX), following the rectal administration of a suppository containing adjuvants was investigated. A lipophilic base (Witepsol H15) was used. The rectal absorption of LMOX following the administration of a suppository without adjuvants was very low. Diclofenac sodium (DF) was used as an absorption promoter; it enhances rectal membrane permeability. The blood level of LMOX following the addition of DF(10 mg) to the base was increased only about 1.3-fold compared with that achieved with LMOX alone (difference not significant); even with a higher dose of DF, the absorption of LMOX was not sufficient. The release rate of LMOX from the base was slow. When Tween 80, a non-ionic surfactant, was added to improve the release rate of LMOX, the rate was sufficiently increased. The rectal absorption of LMOX on the addition of both Tween 80 and DF was markedly increased compared to that achieved with LMOX alone or with DF. These results indicate that the rectal absorption of LMOX after administration by a suppository was sufficiently improved by enhancing both the release rate from the base and the membrane permeability of the rectum. Lymphatic uptake and blood levels of LMOX were also investigated after the rectal administration of the LMOX preparation containing both Tween 80 and DF; the lymphatic uptake of LMOX was significantly enhanced compared with the LMOX preparation in which only DF was used as an adjuvant. The mechanism whereby adjuvants lead to the absorption of a non-absorbable drug, and the subsequent drug transportation routes through the membrane are discussed.

Therapeutic studies of cefepime (BMY 28142) in murine meningitis and pharmacokinetics in neonatal rats.

Cefepime (BMY 28142) was compared with ceftazidime, cefotaxime, and moxalactam for efficacy in treating experimental meningitis in mice and neonatal rats. Mice were infected intracranially with Streptococcus pneumoniae, S. agalactiae, Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa and treated intramuscularly. Five- to eight-day-old neonatal rats were injected intracisternally with Haemophilus influenzae, S. pneumoniae, and S. agalactiae and treated intraperitoneally. Cefepime was found to be the most active compound against induced meningitis in mice infected with S. agalactiae. Cefepime was as active as cefotaxime against Staphylococcus aureus meningitis, slightly more active than cefotaxime against S. pneumoniae and E. coli, and as active as ceftazidime against K. pneumoniae and P. aeruginosa meningitis. Cefepime was found to be the most active compound against S. pneumoniae and S. agalactiae meningitis in neonatal rats. Against H. influenzae, cefepime was as active as moxalactam and cefotaxime. Ceftazidime was the least active compound. The pharmacokinetics of cefepime in neonatal rats were similar to those of ceftazidime. Both compounds penetrated well into cerebrospinal fluid and brain tissues of uninfected neonatal rats. Relative concentrations were twice as high as those of cefotaxime and moxalactam.

Antibiotic-induced vitamin K deficiency and the role of the presence of intestinal flora.

Cephalosporin antibiotics with N-methyl-thio-tetrazole (NMTT) side chains have been known to be associated with the development of hypoprothrombinemia. However, it has not been fully established whether these symptoms are induced by an inhibition of vitamin K production by intestinal microorganisms or by an inhibitory action of these antibiotics on endogenous vitamin K metabolism. Therefore, an attempt has been made to clarify the above-mentioned ambiguity by using germfree mice in which primary vitamin K deficiency can be established within a short experimental period. Germfree (GF) and conventional (CV) ICR male mice, 8-13 weeks old were used in this experiment. Vitamin K deficient (Def) and menaquinone-4 supplemented diet (MK-4) were fed to the mice in both rearing conditions. In the antibiotic-treated group, sodium latamoxef (LMOX, 300 mg/kg B.W./day) was intraperitoneally administered once a day, and in the control group the same volume of saline (Saline) was administered. Severe vitamin K deficient symptoms were observed in the GF-K-Def-LMOX group, and both prothrombin time (PT) and activated-partial thromboplastin time (APTT) values were prolonged on the 8th day of the experimental period compared with the GF-K-Def-Saline group. Furthermore the mortality rate of GF-K-Def-LMOX group was comparatively higher than that of the Saline group. This study has provided evidence that vitamin K deficiency is amplified by an administration of LMOX even in the absence of intestinal flora.

Quantitative relationship between sensitivity to beta-lactam antibiotics and beta-lactamase production in gram-negative bacteria--II. Non-steady-state treatment and progress curves.

A non-steady-state model is discussed for the study of the interplay between beta-lactamase activity and outer membrane permeability with slowly hydrolysed beta-lactams. The analysis shows: (1) that the simple, steady-state model presented in the accompanying paper remains valid as long as kcat (i.e. k3 with chromosome-encoded class C beta-lactamases) is larger than 10(-3)/sec (generation time = 20 min or more); (2) that among the beta-lactam antibiotics studied here, the complete, non-steady-state model needs only be used in the case of aztreonam; (3) that the term "trapping" should be replaced by "formation of a covalent acyl-enzyme" and that such a phenomenon only contributes significantly to the resistance when penetration and hydrolysis are very slow and the periplasmic beta-lactamase concentration is very high. Aztreonam seems to be the only compound which fulfils the first two conditions.

Effect of cefotaxime, ceftriaxone and latamoxef on blood coagulation in patients on parenteral nutrition.

Plasmatic coagulation parameters were studied in patients on parenteral cephalosporins with different hepatic pharmacokinetics. Sixty patients received either cefotaxime (4 g/day), ceftriaxone (2 g/day) or latamoxef (4 g/day) pre- and postoperatively for at least 5 days at random. They received parenteral nutrition without vitamin K supply and had no oral intake. A significant drop (p less than 0.05) in vitamin-K-dependent coagulation factors was recorded in patients treated with latamoxef, while patients receiving ceftriaxone and cefotaxime did not exhibit a significant change in their plasmatic coagulation parameters. Interference of some cephalosporins with the vitamin-K-dependent hepatic metabolism of clotting factors seems to be likely, rather than a suppression of intestinal vitamin K production by the intestinal microflora.

Comparison of single-dose moxalactam and a three-dose regimen of cefoxitin for prophylaxis in vaginal hysterectomy.

In patients undergoing vaginal hysterectomy, prophylactic use of a single dose of moxalactam was compared with use of a standard three-dose regimen of cefoxitin for efficacy and for rate of postoperative colonization of the vaginal cuff with resistant bacteria. In a prospective, randomized study, patients hospitalized for vaginal hysterectomy received either cefoxitin sodium 2 g intramuscularly on call to the operating room followed by 2 g intravenously every six hours for two additional doses or a single dose of moxalactam disodium 2 g intramuscularly on call. Cultures of the meatal area and of urine were obtained preoperatively; postoperatively, cultures of urine, of the vaginal cuff, and of any site or fluid presumed to be infected were obtained. Data were evaluated for 38 patients in the moxalactam group and 40 patients in the cefoxitin group. There was no significant difference in the incidence of infectious morbidity (7.5% of cefoxitin-treated patients and 10.5% of moxalactam-treated patients). Infectious morbidity was not related to age, length of surgery, or estimated blood loss. The incidence of febrile morbidity was not significantly different (7.5% of the cefoxitin group and 13.2% of the moxalactam group). Colonization of the vaginal cuff with resistant organisms occurred in 70% of cefoxitin patients and 71% of moxalactam patients and was a poor predictor of infectious morbidity. In these 78 women undergoing vaginal hysterectomy, single-dose moxalactam and a three-dose regimen of cefoxitin were equally effective for surgical prophylaxis.

A double beta-lactam combination versus an aminoglycoside-containing regimen as empiric antibiotic therapy for febrile granulocytopenic cancer patients.

The double beta-lactam combination of moxalactam plus piperacillin was compared with the aminoglycoside-containing regimen of moxalactam plus amikacin in a prospective, randomized trial of empiric therapy for 302 febrile episodes in granulocytopenic cancer patients. The moxalactam/piperacillin regimen was found to be as effective as the moxalactam/amikacin regimen (70 percent overall responses); responses with moxalactam/piperacillin and moxalactam/amikacin were similar for microbiologically documented infections (24 of 37, 65 percent, versus 20 of 35, 57 percent), for the subgroup with bacteremias (19 of 32 versus 14 of 28), and for clinically documented infections (41 of 58, 71 percent, versus 40 of 48, 83 percent). Responses were similar also for bacteremia in patients with persistent, profound (less than 100/microliter) granulocytopenia. Among profoundly (less than 100/microliter) granulocytopenic patients with gram-negative bacteremia, an increase in the granulocyte count to more than 100/microliter during therapy and a peak bactericidal activity of 1:16 or more (the latter noted in seven of nine moxalactam/piperacillin trials and six of nine moxalactam/amikacin trials) correlated with a favorable clinical response in 85 percent (p less than or equal to 0.00003) and 92 percent (p less than or equal to 0.044), respectively. Although serious side effects were minimal with either regimen, the double beta-lactam combination was associated with significantly less frequent nephrotoxicity (two of 145 versus 12 of 130; p less than or equal to 0.003) and ototoxicity (none of 34 versus seven of 34; p less than or equal to 0.006). The double beta-lactam combination of moxalactam plus piperacillin was found to be as effective as moxalactam plus amikacin but to have significantly less nephro- and ototoxicity.

Cefotetan in the treatment of obstetric and gynecologic infections.

The efficacy, tolerance, and safety of cefotetan--a new 7-alpha-methoxy cephalosporin--was assessed in controlled and uncontrolled evaluations involving 131 evaluable patients hospitalized with obstetric and gynecologic infections. The 99% satisfactory clinical response rate obtained with this drug was equivalent to that obtained with either moxalactam or cefoxitin, yet the mean amount of cefotetan given was lower than that of the other two drugs. Cefotetan was well tolerated and produced no major adverse reactions. In this era of Diagnosis Related Groups and cost containment, the twice-daily dosage schedule of cefotetan is a decided cost benefit.

Experience with the use of cefotaxime in the treatment of bacterial meningitis.

Information on 62 bacteriologically confirmed cases of bacterial meningitis treated with cefotaxime in this country was obtained retrospectively from infectious disease consultants. This series of cases differed markedly from the world cumulative case data thus far presented. One of the two most common organisms treated was the pneumococcus (allergy to penicillin or misdiagnosis of the Gram stain results were the major reasons given). The other organism was Klebsiella. Unanticipated bacteriologic successes were noted in two cases of staphylococcal meningitis secondary to parameningeal foci. The bacteriologic cure rate and survival rate were about 85 percent. Failure of monotherapy was seen in one case of Pseudomonas meningitis, as well as in three of five cases of Enterobacter meningitis. In addition, two cases of Escherichia coli meningitis in which moxalactam therapy inexplicably failed were cured with cefotaxime. Close analysis of killing kinetics appeared to explain the Enterobacter and E. coli failures. Thus, overall not all gram-negative species and not all isolates of any particular species that cause meningitis can be successfully treated by cephalosporins. Data obtained during the investigative trials do not appear to be entirely predicative of what occurred during the free clinical use of an antibiotic. Post-investigatory follow-up and surveillance of all newly introduced therapeutic agents are needed.

Kinetics and bactericidal effect of gentamicin and latamoxef (moxalactam) in experimental Escherichia coli endocarditis.

The pharmacokinetics of gentamicin and latamoxef (moxalactam) were examined in serum, normal heart valves, sterile cardiac vegetations and vegetations infected with Escherichia coli. Penetration of antibiotics into heart valves and vegetations was rapid; the maximum concentration was achieved in both sites at the end of a 20 min iv infusion. However, both antibiotics penetrated better into vegetations than into normal heart valves. In rabbits with left-sided endocarditis, similar antibiotic levels were found in infected vegetations after one or 22 im injections. After 11 im injections (one every 8 h) of latamoxef (15 mg/kg) the bacterial titre (cfu/g) was significantly reduced, but not nil, despite concentrations about 40 times the MBC for this antibiotic in the vegetations. Afer 22 im injections, vegetations in rabbits receiving latamoxef were sterile and were significantly reduced in those receiving gentamicin (1.5 mg/kg/im), concentrations of which in the vegetations were inferior to the MBC. Our results suggest that the in-vivo antibacterial effect depends on local antibiotic levels, kinetics of killing and duration of contact between antibiotic and bacteria.

[Neonatal meningitis: is the combination ampicillin-gentamycin obsolete?]. / Neonatale meningitis: is de combinatie ampicilline-gentamicine achterhaald?

The course of E. coli-meningitis in two infants, treated with latamoxef (moxalactam) in combination with ampicillin is described. Because of the disappointing results the potential value of latamoxef for therapy of Gram-negative enteric meningitis of infancy is discussed.

A multicenter comparative trial of tobramycin and ticarcillin vs moxalactam and ticarcillin in febrile neutropenic patients.

During a multicenter prospective randomized trial in febrile neutropenic patients (neutrophil count, less than 1,000/cu mm), 103 episodes were treated with tobramycin sulfate plus ticarcillin disodium (TT) while 117 were treated with moxalactam plus ticarcillin disodium (MT). The majority of patients had an underlying diagnosis of leukemia (60%) and most (62.8%) had granulocyte counts of less than 100/cu mm at the start of therapy. The response rates for clinically or microbiologically documented episodes were 38 of 60 (55.1%) for TT and 38 of 64 (59.4%) for MT. The MT regimen appeared to be more effective for gram-positive infections (56% vs 33%) while TT appeared more effective for gram-negative infections (64% vs 40%). Nephrotoxicity attributable to study drugs occurred in only 2.3% of cases (one on each treatment arm). Prolongation of the prothrombin time was observed in only six of 78 (7.7%) in the TT arm as compared with 39 of 103 (38%) in the MT arm. Neither regimen was adequate for the unusually high frequency of gram-positive pathogens seen during this study.