Moxalactam for obstetric and gynecologic infections. In vitro and dose-finding studies

Use of third-generation cephalosporins. Anaerobes

The third-generation cephalosporins have an increased spectrum of activity against gram-negative bacteria, moderate activity against anaerobic bacteria, and reduced anti-gram-positive activity as compared with earlier cephalosporins. This spectrum allows the drugs to be considered as monotherapy for the treatment of mixed aerobic-anaerobic infections and as prophylaxis in patients in whom such mixed flora are expected. In vitro testing of anaerobes with the third-generation cephalosporins shows susceptibility to be method dependent, with regional differences also observed. The microtube broth dilution method shows the best relationship to in vivo results. Moreover, the apparent in vitro susceptibility or resistance does not always correlate with clinical efficacy. Clinical studies indicate that the expanded-spectrum third-generation cephalosporins may be used in place of combination therapy in patients with polymicrobial infection or as prophylaxis when mixed microflora are expected.

Single-agent therapy for women with acute polymicrobial pelvic infections

Pathogens that cause acute polymicrobial female pelvic infections usually do not differ from those that compose the normal flora of the lower reproductive tract. Accurate identification of these bacteria is difficult because cultures obtained via the lower tract can easily be contaminated. Although use of a double-lumen catheter-protected brush culture cannot completely eliminate the risk of contamination, it is the least invasive method for obtaining culture material from the upper reproductive tract. Compounding the problem of accurately identifying pathogens that cause acute upper tract infections is the fact that bacteria appear to be present in the upper tracts of asymptomatic women with normal examinations. Because of these problems and because of the polymicrobial nature of these infections, empiric therapy frequently includes more than one antimicrobial agent. Newer, semisynthetic penicillins and cephalosporins have expanded spectrums of in vitro activity against most of the bacteria frequently recovered from pelvic infection sites. Comparative clinical trials have shown these agents to be as effective when used alone as is combination therapy. With few exceptions, empiric monotherapy with one of these newer antimicrobials will be curative for women with acute upper tract infection, will have less potential toxicity, will require less space, materials, and manpower to administer, and will be less expensive.

Third generation cephalosporin antibiotics in surgical practice

The new third generation cephalosporins have a significantly greater spectrum of action against gram-negative bacteria likely to be encountered in surgical infections. This expanded spectrum may permit these drugs to be used in place of combination therapy in patients with polymicrobial infections; however, current evidence does not indicate superior results with these agents over earlier generation choices for surgical prophylaxis. The toxicity profile of these drugs warrants close monitoring for serious complications.

Comparative clinical evaluation of ticarcillin plus clavulanic acid versus clindamycin plus gentamicin in treatment of post-cesarean endomyometritis

A new single-antibiotic combination of ticarcillin and clavulanic acid was compared with the standard two-drug regimen of clindamycin and gentamicin in the treatment of post-cesarean endomyometritis. The regimens were as follows: 3 g of ticarcillin plus 100 mg of clavulanic acid intravenously every four hours; or 600 mg of clindamycin intravenously every six hours plus 3 to 5 mg/kg per day of gentamicin intramuscularly. The prospective randomized schedule was calculated such that half the patients were assigned to each treatment group. The diagnosis of endomyometritis was based upon an elevated oral temperature of 100.4 degrees F or higher on any two occasions, excluding the first 24 hours after delivery, uterine tenderness, and the absence of other foci of infection. Lochial discharge was foul in most cases. Forty-seven patients were treated. Treatment was successful in all patients who received clindamycin and gentamicin; ticarcillin plus clavulanic acid failed in two of 23 (9 percent) patients. Patients in whom treatment failed did not appear to be different from those in whom treatment was successful on demographic variables or in terms of risk factors for endomyometritis. The difference between the treatment failure rates was not statistically significant. This study suggests that the single-drug combination of ticarcillin plus clavulanic acid is effective in the treatment of post-cesarean endomyometritis when compared with the standard regimen of clindamycin and gentamicin.

In vitro activity of cefbuperazone and other antimicrobial agents against isolates from the female genital tract

Cefbuperazone (BMY 25182), a new cephamycin, showed activity similar to those of moxalactam and other cephalosporin-cephamycins against aerobic and anaerobic bacteria from female genital tract infections. MICs of the antimicrobial agents were less than or equal to 16 micrograms/ml for greater than 97% of organisms tested. All of the anaerobic bacteria tested were susceptible to clindamycin, metronidazole, and chloramphenicol.

Cefotaxime treatment for women with community-acquired pelvic abscesses

Forty-one women with pelvic abscesses complicating salpingitis were treated with parenteral cefotaxime, a newer cephalosporin. Abscesses ranged in size from 4 by 4 to 13 by 15 cm, and in 10 women (24%) they were greater than or equal to 10 cm. Neisseria gonorrhoeae was recovered from the endocervix in 17 women (41%). A mean of 26.7 gm of cefotaxime was given over a mean of 6.5 days, and operation was not required during initial therapy. Only two women (5%) required the addition of another antimicrobial. Chronic pelvic pain and recurrent infection were infrequent during the 31- to 43-month follow-up period. Five women (12%) were readmitted for elective surgical therapy because of persistent or recurrent adnexal mass 1 to 33 months following study entry. Six (15%) women became pregnant and were delivered of their infants a mean of 25 months following cefotaxime therapy.

Comparison of moxalactam and cefazolin as prophylactic antibiotics during cesarean section

Prophylactic antibiotics have been shown to be effective in decreasing the incidence of febrile morbidity associated with cesarean section after labor. However, the relative effectiveness of different single antibiotics has been studied infrequently, and these investigations have been limited by small patient samples. Several new, broad-spectrum antibiotics are now available, and any further benefit from more traditional antibiotics for surgical prophylaxis remains untested. A randomized prospective double-blind therapeutic trial was therefore undertaken to compare the value of a first-generation cephalosporin (cefazolin) with a new third-generation cephalosporin (moxalactam). Between July 1981 and June 1983, 254 qualifying women who underwent primary cesarean section after labor were randomly chosen for either of the two treatment groups. Although not statistically significant, the rates of febrile morbidity, wound infection, and endometritis were less for those treated with cefazolin (4.0, 3.2, and 0.8%, respectively) than for those treated with moxalactam (9.2, 7.7, and 1.6%, respectively). No serious adverse effects were apparent in the mother and newborn infant from short-term exposure to either drug. Although the newer, more expensive, and broader-spectrum cephalosporin, moxalactam, was associated with a low postoperative febrile morbidity rate and short postpartum hospitalization, it was no more beneficial than cefazolin.

The cephalosporin antibiotic agents--III. Third-generation cephalosporins

The third-“generation” cephalosporin antibiotics (Table 1) represent a class of agents with an expanded gram-negative spectrum of activity beyond that of the first- and second-“generation” cephalosporins. Greater stability to beta-lactamases produced by gram-negative organisms confers to these agents a greater bactericidal action against the Enterobacteriaceae. Large bacterial inocula (105/ml) in vitro significantly increase the minimum inhibitory and bactericidal concentrations (MIC and MBC) explaining treatment failures with these agents in infections associated with large numbers of organisms. The pharmacokinetic features of some of the agents allow prolongation of dosing intervals, and enhanced tissue penetration amplifies their clinical utility in infections distant from the bloodstream (eg, meningitis).

Patient costs in the prevention and treatment of post-cesarean section infection

The total cost to the patient is an important consideration in the selection of antimicrobials for prevention and treatment of post-cesarean section endomyometritis. We compared the cost to the patient of commonly used therapeutic and prophylactic agents in a theoretical model population of 450 women who were delivered by cesarean section. Cost of the drug alone on a per gram, per dose, or per day of therapy basis is not an accurate way of estimating the cost eventually paid by the patient. The therapeutic efficacy, frequency of administration, and need for ancillary services for each treatment regimen affect significantly the patient's costs.

Moxalactam versus cefazolin prophylaxis for vaginal hysterectomy

Moxalactam is a newer beta-lactam antibiotic with increased activity and an extended antimicrobial spectrum. Three 1 gm doses were given to women scheduled for elective vaginal hysterectomy. This perioperative regimen was prospectively compared to identical doses of cefazolin, a first-generation cephalosporin of proved efficacy. The overall incidence of major postoperative infection in 193 women was less than 5% and there were no significant interregimen differences. The incidence of major infection was directly related to the type of procedure performed.

A double-blind, randomized comparison of moxalactam versus clindamycin-gentamicin in treatment of endomyometritis after cesarean section delivery

A double-blind comparison of clindamycin plus gentamicin versus moxalactam plus placebo was performed for the treatment of endomyometritis after cesarean section delivery. Entry criteria were uterine tenderness, temperature greater than or equal to 101 degrees F, and leukocytosis. Uterine specimens were obtained for culture via a single-lumen transcervical catheter. Bacteremia occurred in 10% of patients. Among the 57 patients treated with clindamycin plus gentamicin, there were two clinical failures and four side effect failures (diarrhea in two, allergic reaction in two). Among the 56 patients in the moxalactam group, there were four clinical failures and one side effect failure (diarrhea). Both regimens had good cure rates, with no significant differences in cures or postoperative hospital stay.

Pharmacokinetics of cefoxitin in patients at term gestation: lavage versus intravenous administration

Despite the increasing popularity of antibiotic prophylaxis to reduce febrile morbidity in patients who undergo cesarean delivery, little is known of the pharmacokinetics of antibiotics in the patient at term gestation. This study was designed to elucidate the pharmacokinetics of cefoxitin when administered intravenously or by uterine and peritoneal lavage at cesarean section. Significant differences were found in the values for total body clearance area under the serum concentration-time curve (AUC), and K21 of cefoxitin administered intravenously to pregnant patients at term gestation compared to values for these parameters observed in nonpregnant patients. The concentration of cefoxitin in decidual tissue after uterine and peritoneal lavage with the antibiotic was 92.5 +/- 10.1 micrograms/gm (mean +/- SEM), whereas the concentration of cefoxitin in decidual tissue after intravenous administration of the antibiotic was 36.9 +/- 10.5 micrograms/gm (mean +/- SEM). This difference is statistically significant (p less than 0.05). We conclude that the pharmacokinetics of cefoxitin are altered in the pregnant patient as evidenced by the increased rapidity of clearance of the antibiotic (total body clearance for cefoxitin in pregnant patients, 20.41 L/hr). Moreover, uterine and peritoneal lavage results in significant tissue concentrations of antibiotic, which is of potential importance since the decidua is a presumed site of initiation of bacterial infection after cesarean section.

Comparative study of piperacillin versus cefoxitin in the treatment of obstetric and gynecologic infections

Piperacillin sodium (Pipracil, Lederle Laboratories, Wayne, New Jersey), a new semisynthetic penicillin, demonstrated in vitro activity against a broad spectrum of clinical pathogens. It is active against most strains of the clinically important gram-negative aerobic or facultative bacteria and against virtually all the clinically important anaerobic organisms, including Bacteroides fragilis and Bacteroides bivius. This broad antibacterial spectrum suggested that piperacillin might be an effective single antimicrobial agent for the treatment of mixed aerobic/anaerobic infections in obstetric and gynecologic patients. In this study, the clinical efficacy and safety of piperacillin was compared with that of cefoxitin in the management of pelvic infections. There were 23 patients in the piperacillin group (acute salpingitis, 12; endomyometritis, 7; pelvic cellulitis, 2; tuboovarian abscess, 2) and 25 patients in the cefoxitin group (acute salpingitis, 13; endomyometritis, 10; tuboovarian abscess, 2). An average of six bacteria were isolated from each patient. Aerobic bacteria only were recovered from 12.5%, anaerobic bacteria only in 6.5%, and both aerobic and anaerobic bacteria were present in 82.5% of patients. Overall, 21 of 23 (91%) of the piperacillin treatment group and 23 of 25 (92%) of the cefoxitin group responded to therapy with antimicrobial agents alone. The major cause of failure was the presence of an abscess. Piperacillin was shown to be an effective single agent for the management of pelvic infections caused by mixed aerobic and anaerobic bacteria. In addition, piperacillin proved to be safe and well tolerated.

Maternal and fetal pharmacokinetics of moxalactam given intrapartum

Two grams of moxalactam was given intravenously to 28 women at high risk for infection following cesarean delivery. After a mean time of 48 minutes from infusion, maternal sera, cord sera, and uterine tissue obtained at delivery had concentrations of moxalactam of 62 micrograms/ml, 22.2 micrograms/ml, and 9.6 micrograms/gm, respectively. The maternal serum half-time was calculated to b e 2.1 hours. R and S epimeric distribution was determined in these sera and tissues, and the mean R/S ratios were 0.95, 0.93, and 1.22 for the three groups, respectively. The significance of these observations is discussed. A new method in which a high-pressure liquid chromatographic assay is used is described, and results are compared to those obtained with the microbiological assay. The high-pressure liquid chromatographic method was found to be quick, accurate, an reproducible.

In vitro activity of new beta-lactam antibiotics and other antimicrobial drugs against anaerobic isolates from obstetric and gynecological infections

The in vitro activities of N-formimidoyl thienamycin, clindamycin, chloramphenicol, metronidazole, cefoperazone, cefotaxime, cefoxitin, moxalactam, penicillin G, and piperacillin were determined against 158 anaerobic bacteria isolated from endometrial wash cultures of women with pelvic infections. In general, N-formimidoyl thienamycin was the most active, with all organisms inhibited by less than or equal to 0.5 microgram/ml. Chloramphenicol, clindamycin, and metronidazole inhibited all organisms by less than or equal to 8 microgram/ml. The penicillins and cephalosporins exhibited variable activity of lesser degrees.

A comparative evaluation of moxalactam: antimicrobial activity, pharmacokinetics, adverse reactions, and clinical efficacy

Although moxalactam is not, technically speaking, a cephalosporin it is chemically and microbiologically so closely related to those compounds that it can be viewed as a member of the cephalosporin family. Moxalactam has a spectrum of activity that includes both gram positive and gram negative bacteria. Its gram positive activity is less than earlier cephalosporins, but its activity against the Enterobacteriaceae is similar to that of the aminoglycoside family of antibiotics in most comparative studies. Although moxalactam is considerably less active against gram positive bacteria than cefotaxime, another third generation cephalosporin, its higher and more prolonged serum levels probably offset this disadvantage. Compared to cefoperazone, the stability of moxalactam to many types of beta lactamases produced by gram negative bacteria may be advantageous in the therapy of infections caused by hospital-acquired pathogens. Clinical studies suggest that moxalactam can be used for empiric therapy of suspected gram negative infections when Pseudomonas and other non-fermentative bacteria, such as Acinetobacter, are not suspected. Impressive improvements in the survival of patients with gram negative enteric bacillary meningitis have been reported. Although moxalactam, cefotaxime, and cefoperazone have activity against Pseudomonas aeruginosa, none of these antibiotics should be used alone as therapy for suspected or proven severe systemic infections caused by this pathogen. Cost is a major problem with all of the new cephalosporin-like antibiotics. While this high cost may be partially balanced by the use of a single agent compared to an antibiotic combination for therapy in some situations, these antibiotics are not cost effective for prophylactic use. Superinfection with fungi, such as Candida, and Streptococcus faecalis have occurred, and toxicities, such as bleeding due to vitamin K deficiency and disulfuram-like reactions, have also been reported. Reports of resistance to moxalactam and the other third generation cephalosporins are of major concern and indicate the need to closely monitor antibiotic susceptibility patterns of hospital acquired organisms if these antibiotics are to be used for empiric therapy of suspected gram negative non-pseudomonas sepsis.

New drug evaluations: moxalactam (Moxam, Eli Lilly)

Moxalactam is a new 1-oxa-beta-lactam antibiotic that is similar in many respects to the third-generation cephalosporins. Moxalactam is exceptionally stable to beta-lactamase enzymes and inhibits most gram-negative aerobic bacteria, with the frequent exception of P. aeruginosa. Moxalactam is active against most B. fragilis organisms and appears to be an effective alternative to an aminoglycoside/clindamycin combination for patients with intraabdominal infections. Moxalactam penetrates through inflamed meninges and may become the drug of choice for gram-negative bacillary meningitis due to susceptible organisms. Moxalactam would be expected to be no more effective than the third-generation cephalosporins for other gram-negative infections, and it has not been clearly shown that these agents are as effective as aminoglycoside antibiotics for most serious gram-negative infections. Because of moxalactam's high cost, its potential for misuse, and its unknown long-term effects on microbial resistance patterns, as well as the lack of comparative efficacy studies for many infections, the hospital use of moxalactam should be closely monitored.