Efficacy of oral ofloxacin for single-dose perioperative prophylaxis in general surgery--a controlled randomized clinical study

BACKGROUND

Perioperative antibiotic prophylaxis surely reduces surgical infection rate. Pharmacokinetic data of oral ofloxacin in combination with its antibacterial spectrum suggest effective protection against perioperative infection. In addition, costs, adverse effects, and induction of microbial resistance are low. Therefore we performed a controlled randomized study comparing oral and intravenous single dose prophylaxis.

METHODS

A total of 61 patients undergoing colonic or pancreatic resection randomly received either a single dose standard intravenous prophylaxis or ofloxacin 400 mg and metronidazole 500 mg orally 2 h before surgery. Postoperative infections were recorded for 3 weeks.

RESULTS

Groups were very well comparable regarding age, overweight, concomitant disease, type and duration of surgery, blood loss, and volume support. Infectious complications occurred in 14.8% after parenteral and 3.3% after enteral antibiotic prophylaxis. There was no difference in post-operative hospital stay.

CONCLUSION

The data demonstrate that single-dose oral ofloxacin is at least as effective as a standard intravenous prophylaxis in patients with colonic or pancreatic resection. It offers significant advantages regarding costs and ease of administration.

A prospective randomized trial of ceftazidime versus netilmicin plus mezlocillin in the empirical therapy of presumed sepsis in cirrhotic patients

Aminoglycosides are frequently used to treat sepsis in patients with liver disease. However, it has been suggested that cirrhotic patients are particularly sensitive to aminoglycoside-induced renal dysfunction. We investigated the efficacy and incidence of renal impairment with netilmicin plus mezlocillin compared with ceftazidime in 128 cirrhotic patients who required empirical treatment for sepsis. Renal impairment developed in 8 of 63 (13%) patients receiving netilmicin compared with 2 of 65 (3%) patients receiving ceftazidime (P < .05); it occurred despite regular monitoring of trough netilmicin levels. Renal impairment was present at the time of death in 1 of 13 (8%) patients treated with ceftazidime compared with 5 of 9 (56%) of the netilmicin patients (P < .05). Mortality rates were similar in the two groups (ceftazidime 20%, aminoglycoside 14%; P = NS). Renal dysfunction is significantly more frequent in cirrhotic patients treated with netilmicin but with careful attention to dosage and fluid management the clinical effect is likely to be relatively modest.

[Surgical revision of the pilonidal sinus with single shot antibiosis]

For a therapy of the pilonidal sinus there are different surgical and non-surgical methods to be found in literature. In our surgical wing 140 male patients have been operated on this disease from September 1990 to July 1992. 16 cases out of these 140 were re-operations. Using a special surgical technique we applied the excision with a primary closure under single-shot antibiosis in 139 cases. By modifying this antibiosis prophylaxis we could reach a primary success healing rate of up to 96%. A retrospective study among our patients showed a recurrence rate of 5%.

Cervicofacial actinomycosis (a case report)

Actinomycosis is now a very uncommonly diagnosed human disease. Major medical centers report approximately one case a year. The pathogenesis of actinomycosis is unclear, but trauma provides a portal of entry. The cervicofacial form is the most common and usually appears as a chronic swelling with one or more draining sinus tracts. For treatment, penicillin in high doses is suggested. This case report presents a case of cervicofacial actinomycosis in a 14 year old boy which was misdiagnosed for a long time and the treatment of the disease with mezlocillin, a new antibiotic in the treatment of actinomycosis.

Single-dose antibiotic prophylaxis in maxillofacial surgery

The clinical efficacy of short-term antimicrobial prophylaxis with either one shot of ceftriaxone (1 g) or a course of 3 injections of a fixed combination of mezlocillin (2 g) and oxacillin (1 g) administered over 24 h was studied in a prospective randomized clinical study of 100 patients undergoing elective maxillofacial surgery. Tissue and plasma concentrations of the antibiotics were determined by high-pressure liquid chromatography in 6 tumor surgery patients from each treatment group. Statistical analysis showed the treatment group to be comparable both demographically and with respect to the types of surgery performed and the durations of the procedures. Only 1 patient in each group developed a postoperative wound infection. It is concluded that 1 g ceftriaxone given 30 min preoperatively meets the pharmacokinetic requirements for perioperative antimicrobial prophylaxis in maxillofacial surgery.

[Ultrasound-controlled percutaneous drainage of subhepatic liver abscess after conventional cholecystectomy]

From February 1984 to August 1991 subhepatic abscesses were detected by ultrasound in 7 patients with fever following conventional cholecystectomy. Cholecystectomy had been performed in all these patients 6 to 27 days previously. All patients had received antibiotic prophylaxis at the time of cholecystectomy. Three of the 7 patients were at first afebrile, later on again febrile. In the remaining 4 of the 7 patients antibiotic treatment was continued in the face of persistent fever. Percutaneous catheter drainage was performed in all patients. In all of the 7 cases the subhepatic abscesses resolved completely within 10 days to 7 weeks.

[Bile composition and antibiotic excretion. Observations with T-drainage]

Patients comparable in disease, therapy and serum bilirubin concentration were either treated with mezlocillin intravenously or not at all. The bile of each patient was collected either from a T-drainage or from a percutaneously placed drainage into the bile ducts. The concentrations of GGT and AP, which were liberated by destroyed liver cells, and of bilirubin and mezlocillin, which were secreted actively, were analysed. Those patients who had normal serum bilirubin concentrations had a significantly higher biliary bilirubin excretion than those with high serum bilirubin level. The maximum excretion was after 4 hours. While the biliary concentration of bilirubin decreased, the concentration of secreted mezlocillin increased. Due to destroyed liver cells those patients with pathologically elevated blood bilirubin levels had a 50-fold lower mezlocillin excretion than those with normal blood values.

[Prospective study of the clinical value of C-reactive protein in amniotic infection syndrome]

In an open prospective investigation the median levels of C-reactive protein were determined in annormal collective. The median lies at 0.8 mg/dl in maternal serum withdrawn sub partu and in umbilical vein blood, and at 1.45 mg/dl immediately after ligation of the cord. Hopes on finding a biochemical parameter that could supply reliable information already during labour on a possible inflammatory infection in mother and child, did not materialize from the data found. Prediction of an infection of the newborn using CPR is only minimal. The most important practical information is given by the negative CRP in the umbilical vein blood. In this case the probability of an infection of the newborn is very slight. A high temperature during labour was the best predictor of the probability of endometritis puerperalis. This clinical finding, due to its specificity, is superior to CRP and the other parameters investigated.

Infected bullae: a recognizable entity

Infected bullae are seldom diagnosed. They are frequently confused with pulmonary abscess. We present a case with a characteristic evolution. Bullae were identified previous to the infection. The illness developed gradually with scanty sputum, pleuritic pain and finally a febrile illness. Fever abated 48 hours after initiating two weeks of therapy with intravenous Clindamycin and Amikacin. As it is commonly seen, radiographic resolution was slow but it was complete in 8 weeks. Recognition of infected bullae is important to avoid inappropriate diagnostic or therapeutic interventions.

[Sulbactam in combination with mezlocillin, piperacillin or cefotaxime. Clinical and bacteriological results in the treatment of severe bacterial infections]

An open multicenter study on inpatients of 12 german hospitals was performed to investigate efficacy and safety of sulbactam in combination with mezlocillin, piperacillin or cefotaxim in severe bacterial infections. In total 155 patients were enrolled. The following infections were diagnosed: 48 lower respiratory tract infections, 66 intraabdominal infections, 34 skin/soft tissue infections including post operative wound infections and 5 complicated urinary tract infections. 55 patients received 3 daily doses of 4 g mezlocillin + 1 g sulbactam, 52 patients received 3 daily doses of 4 g piperacillin + 1 g sulbactam and 48 patients received 3 daily doses of 2 g cefotaxim + 1 g sulbactam. Antibiotics and sulbactam were administered concomitantly via intravenous short infusion. Mean duration of therapy was 8 days. Endpoints for assessment of therapeutic efficacy were cure (complete resolution of pretreatment signs and symptoms of the infection) or improvement (marked reduction or partial disappearance or pretreatment signs and symptoms, no further antibiotic therapy required) as well as eradication of pretreatment pathogens. 141 (92%) of 153 evaluable patients were successfully treated (98 cures and 43 improvements), therapy failed in 12 patients (7.8%). Success rates of the 3 sulbactam combinations were almost identical: 91% for mezlocillin/sulbactam, 92% for piperacillin/sulbactam and 93% for cefotaxim/sulbactam. 106 patients (68.4%) were also bacteriologically evaluable. In these patients 192 bacterial pathogens were isolated prior to study therapy, 55 patients had mixed infections. In 96 patients (90%) pretreatment pathogens were eradicated (180 strains = 94%).(ABSTRACT TRUNCATED AT 250 WORDS)

[Excretion of beta-lactam antibiotics in human parotid saliva]

We investigated the penetration of beta-lactam antibiotics into parotid saliva after intravenous administration. Neither mezlocillin nor oxacillin could be detected in parotid saliva, but cefotaxime (CTX) and cefotiam (CTM) penetrated parotid saliva very well. While salivary CTM concentrations reached peak values (9.52 +/- 3.4 mg/l) within 30 min of the end of infusion, the highest CTX concentrations in parotid saliva (5.84 +/- 2.6 mg/l) were observed after 90 min. After 300 min the salivary CTM levels were below the limit of detection, while the mean CTX concentration even 360 min after the end of infusion was 2.27 +/- 1.23 mg/l. Both CTX and CTM achieve salivary concentrations that are inhibitory against the prevailing pathogens causing suppurative parotitis, and thus promise to be effective for the treatment of this disease. Furthermore, the excretion of comparatively high concentrations of both drugs into the mouth achieves a selective decontamination of the mucosal surfaces of the upper aerodigestive tract so that they are suitable for perioperative prophylaxis in head and neck surgery.

[Perioperative preventive use of antibiotics in neurosurgery. Experience with a fixed antibiotic combination of mezlocillin and oxacillin (optocillin)]

We report a retrospective account of 200 patients who have been surveyed after having undergone neurosurgical intervention. They received as perioperative antibiotic prophylaxis a combination of Mezlocillin and Oxacillin in a ratio of 2:1 (Optocillin) in their management. The clinical and bacteriological efficacy including the side effects was examined with standardisation of sterility measures in the operating theatre, careful standardised operative procedures and ward after care. No problems in wound healing were found. There was no certain evidence of side effects.

Adverse reactions to prolonged treatment with high doses of carbenicillin and ureidopenicillins

Charts were reviewed for 63 patients whose chronic pseudomonas osteomyelitis was treated with high doses of extended-spectrum penicillins for prolonged periods. The incidence of untoward drug reactions was significantly higher than expected. Carbenicillin evoked adverse reactions in 22.8% of patients. However, most of these reactions were mild, and a change of drug was required in only 5.7% of cases. No adverse drug reactions were observed with cumulative doses of less than 750 g. In contrast to carbenicillin, the ureidopenicillins were associated with adverse reactions in 67.7% of patients; most reactions were moderate to severe in intensity; a cumulative dose of greater than 250 g produced adverse reactions; and discontinuation or change of therapy was required in 51.6% of cases. The main adverse reactions to both carbenicillin and the ureidopenicillins included rash, drug fever, leukopenia, eosinophilia, thrombocytopenia, and hepatic damage.

Human intestinal tissue antibiotic concentrations. Clindamycin, gentamicin, and mezlocillin

An antibiotic, to be effective for prophylaxis in abdominal trauma, should quickly achieve high concentrations in the intestinal wall and at enough inhibitory levels to kill most aerobic and anaerobic bacteria that are potential contaminants at the site of surgical incision. Therefore, we studied the intestinal tissue levels of clindamycin, gentamicin, and mezlocillin to see whether the tissue levels achieved by these antibiotics in the intestinal tissue were adequate. A single dose of mezlocillin, 4 grams; clindamycin, 600 mg and gentamicin, 80 mg; quickly reached the desired concentrations, i.e., 52.3, 9.69 and 6.1 micrograms/gram of intestinal tissue respectively. These levels were high enough to inhibit the growth of most isolates of E. coli and B. fragilis, common pathogens involved in intra-abdominal abscess.

Antibiotic therapy in preterm premature rupture of membranes: a randomized, prospective, double-blind trial

The use of antibiotics in the management of preterm, premature rupture of membranes remains controversial. By use of a prospective randomized double-blind design we investigated the maternal-fetal benefits associated with antibiotic therapy in 85 women with premature rupture of membranes at 34 weeks' estimated gestational age. In the treatment group 40 patients received intravenous mezlocillin for 48 hours followed by oral ampicillin until delivery. In the control group 45 patients received intravenous and oral placebo. Patients who received antibiotics had chorioamnionitis and endometritis less frequently than the control group (p less than 0.01 and p less than 0.05). Pathologic examination of the placentas showed a lower incidence of chorioamnionitis in the treatment group (p less than 0.05). The period from premature rupture of membranes to delivery (latency) was prolonged with antibiotics (p less than 0.05) and resulted in significant weight gain in the infants in the antibiotic group (p less than 0.0001). These infants also had higher 1- and 5-minute Apgar scores. Clinically suspected sepsis, respiratory distress syndrome, intraventricular hemorrhage, perinatal death rate, and prolonged hospitalization (greater than 30 days) were also increased in the control group.

[Infections in obstetric-gynecologic surgery: chemo-antibiotic prophylaxis and therapy. A bibliographic review]

The Authors review, on the basis of their experience, the literature data concerning chemo-antibiotic prophylaxis in gynaecological surgery. Prophylaxis is widely employed although some important aspects are still under evaluation: bacterial selection and resistance, benefit in case of abdominal hysterectomy or elective Cesarean section, risk of pseudomembranous colitis. The most effective drugs are Piperacillin/Mezlocillin given in a single dose preoperatively. The same drugs are useful in the treatment of postsurgical infections.

Prophylactic mezlocillin-netilmicin combination in permanent transvenous cardiac pacemaker implantation: a single-center, prospective, randomized study

A prospective, randomized study was carried out in order to assess the efficacy and safety of the mezlocillin-netilmicin combination in the prophylaxis of first permanent transvenous cardiac pacemaker implantation. Five hundred and fifty-two consecutive patients were randomly administered either 2 g mezlocillin and 200 mg netilmicin both as an i.v. bolus before implantation or 2g mezlocillin before and then 6 and 12 hours after surgery and 200 mg netilmicin before and then 12 hours after implantation. No adverse events were seen. Neither pocket nor electrode infections were observed in the 457 subjects still alive (mean follow-up: 29.2 months) or in patients who died after 1 year of follow-up (mean follow-up: 20.1 months) or before this time (mean follow-up: 4.7 months). The serum and pocket concentrations of mezlocillin and netilmicin at the end of surgery were found to be adequate to cover microorganisms that most often cause infections, including methicillin-resistant staphylococci.

Medical management of chronic suppurative otitis media without cholesteatoma in children

To determine whether systemic administration of antibiotics may eliminate or reduce the need for tympanomastoid surgery in chronic suppurative otitis media without cholesteatoma, we undertook a randomized, prospective study comparing three regimens: (1) daily suction and débridement, with intravenous administration of mezlocillin until 3 days after the discharge stopped, (2) daily suction and débridement, with intravenous use of ceftazidime until 3 days after the discharge stopped, and (3) daily suction and débridement without antibiotics. No topical antimicrobial agents were used during the study. Fifty-one patients were included, and 48 children completed the study. The duration of discharge from the ear before treatment was 2 to 123 months (median 20 months). In 26 patients (51%), the disease was bilateral. Aerobic cultures, obtained with the Alden-Senturia middle ear aspirator, yielded Pseudomonas aeruginosa in 98%, enteric gram-negative bacilli in 33%, staphylococci in 25%, and Haemophilus influenzae in 12%. The first 33 patients were randomly assigned to one of the three regimens. In the 21 patients treated with suction and antibiotics (either mezlocillin or ceftazidime), the discharge stopped completely, versus in only 1 (8%) of 12 patients in the suction-only regimen (p less than 0.01). Therefore the following 18 patients were randomly assigned to one of only two groups, which included the two suction-and-antibiotic regimens. In all patients treated initially with antibiotics, discharge stopped after 4 to 18 days (mean 12.0 days), but 25% needed treatment for greater than 14 days. Amoxicillin prophylaxis was administered to 27 (56%) of the patients after completion of therapy. All patients were followed for 6 months. Drainage recurred in 12 (25%) patients during the first 3 months after the study. The recurrence rate was not affected by the antibiotic regimen, the patient's age, the duration of drainage before initiation of antibiotic therapy, or prophylaxis. We conclude that intravenous wide-spectrum antibiotic therapy in conjunction with daily suction and débridement is efficacious for the treatment of chronic suppurative otitis media without cholesteatoma.

Single-dose antibiotic prophylaxis in patients at high risk for infection in biliary surgery: a prospective and randomized study comparing cefonicid with mezlocillin

The usefulness of antibiotic prophylaxis in biliary surgery is well established. When antibiotic prophylaxis is not used, wound infection rates after biliary surgery range from 10% to 25%. With antibiotic prophylaxis, the rates can be reduced to less than 5%. Three questions are still controversial: Do all patients undergoing biliary surgery require antibiotic prophylaxis? What is the ideal antibiotic for use in biliary surgery? What should be the duration of antibiotic prophylaxis? In this study we prospectively evaluated the efficacy of a single dose of antibiotic prophylaxis in biliary surgery, administered to patients at high risk for infection, in a trial comparing cefonicid (a cephalosporin with a long half-life) with mezlocillin (a broad-spectrum ureidopenicillin).

[Perioperative preventive use of antibiotics in thoracic surgery--results of a controlled randomized study with optocillin]

There seems to be general agreement that antibiotic prophylaxis should be provided for patients undergoing resections of the lung. In order to obtain further information about the extent of resection beyond which this is necessary, and also to establish the type of prophylaxis that is meaningful over the long term, we carried out a controlled study involving two groups of 100 patients each. In the first group, who received minor resections, ultrashort-term prophylaxis was compared with an 0 group. We were able to show that in high-risk patients with prior pulmonary diseases, prophylaxis is indeed meaningful. In the second group of patients undergoing major resections, antibiotic prophylaxis must be provided; a one-day administration suffices, and long-term administration fails to offer any further advantages.

[Early complications following stapedectomy--surgical or conservative treatment?]

The incidence of sensorineural hearing loss after stapedectomy ranges from 0.6% to 5%. There is evidence that reparative granuloma is a major cause: most authors report that it requires urgent surgery, but this view is not universally accepted. This study analyses 14 stapedectomies that resulted in a sudden or gradual sensorineural hearing loss, often combined with vertigo, and presenting between 1 and 6 weeks after an initial hearing improvement. All patients were treated immediately with a combined infusion of an antibiotic, a corticosteroid and a plasma expander. The sensorineural hearing loss began to improve compared with pre-operative values 9 days later. Thus drug therapy might be sufficient in most cases of sensorineural hearing loss early after stapedectomy, and surgery can be restricted to patients with perilymph fistulae.

A comparison of single-dose systemic Timentin with mezlocillin for prophylaxis of wound infection in elective colorectal surgery. University of Melbourne Colorectal Group

A prospective, randomized, single-blind, controlled clinical trial was undertaken to compare two different prophylactic antibiotic single-dose regimens in patients undergoing elective colorectal surgery. Timentin, a combination of ticarcillin and clavulanic acid, was administered intravenously (3.1 g) to 87 patients. Mezlocillin, a semisynthetic penicillin was given intravenously (2.0 g) to 98 patients. The wound infection rate was 10.6 percent in patients receiving Timentin and 9.7 percent in those receiving mezlocillin (P greater than .05). Multivariate analysis of factors possibly affecting the wound infection rate showed that the presence of a colostomy preoperatively, fecal contamination at surgery, and the surgical group were the only factors that independently achieved a statistically significant association with the development of a postoperative wound infection in this trial (P less than .0001).

[Duration of the preventive use of antibiotics in colorectal surgery--single administration versus short-term prevention]

The effect of a combination of 4 g mezlocillin and 0.5 g metronidazole for the prophylaxis against infections in a one-shot dose immediately preoperatively compared to a short-time dose of 2 days given to 90 patients with resection of colorectal carcinoma was investigated in a prospective and randomized study. 6 patients developed a wound infection in the early postoperative phase; 4 of these infections (3 were severe, 1 was mild) occurred in the one-shot group and 2 in the short-time prophylaxis group. After more than 20 days postoperatively 3 late infections were observed which had a mild course (2 cases in the one-shot group, 1 case in the short-time prophylaxis group). All infections were localized in the sacral wound region in patients with abdominoperineal resection. The abdominal wounds healed per primam in each case. Besides those, 26 infections of the urinary tract were observed, which occurred significantly more often after the one-shot dose (40.9%) than with the short-time prophylaxis (18.6%). Intraoperative smears of the lumen of the bowels showed a remaining bacterial settlement. Besides Bacteroides species, especially Escherichia coli were found among the isolates. Moreover in some cases Clostridium, Klebsiella, Proteus and Pseudomonas could be identified. Smears of the site of operation (sacral/peritoneal cavity) were contaminated in over 50%, above all by Bacteroides species; besides those, E. coli were found most often. The subcutaneous smears showed a growth of the germs only in a few cases. Aerobic bacteria in 93.8%, anaerobic bacteria except for thetaiotaomicron and B. asaccharolyticus in 85.1%.(ABSTRACT TRUNCATED AT 250 WORDS)

Presumptive antibiotics for penetrating abdominal wounds

The optimal antimicrobial agent or agents for penetrating abdominal injuries remains undetermined. During the three year period ending August 1987, 317 consecutive patients undergoing celiotomy for penetrating abdominal trauma were prospectively randomized to receive either mezlocillin, 4 grams every six hours, or clindamycin, 600 milligrams every six hours, and gentamicin, loading dose of 2.0 milligrams per kilogram, then 1.5 kilograms every eight hours. Antibiotics were begun in the emergency department with duration of coverage based on the pattern of injury: the colon, five days; other hollow visceral injury, two days, and all others, one day. Twenty-three patients were excluded because of breach of protocol and 16 others died within 72 hours of presentation. The two study groups, 136 patients receiving mezlocillin and 142 patients receiving gentamicin and clindamycin, were comparable with respect to age, sex, mechanism of injury, shock, intraoperative replacement of blood, abdominal trauma index and distribution of hollow visceral injuries. The over-all incidence of septic morbidity was similar: infections developed in 21 (15 per cent) of the patients receiving mezlocillin compared with 19 (13 per cent) of patients receiving gentamicin and clindamycin. There was no significant difference in major infections (lobar pneumonia and intra-abdominal abscess), with 13 per cent in each group. The offending pathogens were similar. The most common isolates in intra-abdominal abscess were Escherichia coli, Klebsiella and Enterococcus species and anaerobic Bacteroides species. Mezlocillin, an extended spectrum penicillin, achieved similar results, compared with the expensive and potentially toxic combination regimen in patients with penetrating abdominal injuries.

Hepatic intraarterial antibiotic therapy for resistant hepatic abscesses

Liver abscesses present a severe problematic medical entity. The traditional treatment modality consists of surgical drainage, which cannot be accomplished in all circumstances. Other modes of therapy include systemic antibiotics or percutaneous catheter drainage under ultrasonography or computerized tomography. Despite new treatment regimes liver abscesses, to date, are a potentially lethal disease, with a mortality rate of about 50%. We report an innovative approach of high dosage intrahepatic arterial antibiotic infusion for the therapy of hepatic abscesses, which are resistant to conventional treatments. A patient who underwent mastectomy for breast carcinoma, developed liver metastases one year later. She was prescribed systemic chemotherapy for one year, but no antitumor response was evident. Since ther was no evidence for extra-hepatic metastases, intraarterial hepatic chemotherapy was instituted, using an Infusaid (Mi-400) implantable pump. Marked regression of liver metastases was observed. Therapy was withheld after 19 months because of biliary sclerosis development. At this stage, the patient developed liver abscesses, which were resistant to systemic antibiotic therapy. Intraarterial antibiotic therapy, using the implantable pump, was initiated. Following the treatment, a marked improvement in the patients' clinical condition was recorded and shrinkage of the abscesses was evident by ultrasonography. The patient was free of symptoms for three months, when she was readmitted with evidence of terminal metastatic disease and sepsis. It is suggested that intrahepatic arterial antibiotic therapy is an additional mode of treatment for patients with persistent liver abscesses which fail to respond to conventional treatment.

Role of parenteral antibiotherapy in gastrointestinal tract flora suppression. A study in children treated with high-dose chemotherapy and autologous bone marrow transplantation

In order to determine the effect of parenteral antibiotherapy on the fecal flora in patients with profound and prolonged granulocytopenia, we initiated a prospective study of 62 cases of autologous bone marrow transplantation following high-dose chemotherapy. All patients were children from 2 to 18 years old, isolated in a protective environment, receiving a diet low in viable microbial content but no oral non-absorbable prophylactic antibiotics to decontaminate the gastrointestinal tract. Bacteriological analysis of fecal flora was conducted at least once a week before and during parenteral antibiotherapy, administered at the first greater than 38 degrees C febrile episode in these granulocytopenic patients (granulocyte count less than 0.5 X 10(9)/l). The 58 evaluable patients fell into three groups with regard to the systemic antibiotherapy: group A (n = 16): moxalactam + mezlocillin; group B (n = 15): moxalactam + tobramycin; and group C (n = 27): cefotaxime plus gentamicin. Fecal flora suppression was observed in 51/58 cases (88%) (group A: 15/16, group B: 13/15, group C: 23/27). It always occurred within 5 days of initiating parenteral antibiotherapy and persisted in 88% of the 51 patients over the whole period of systemic antibiotherapy. During the latter, fecal recolonization was observed in seven cases (12%), always by Enterobacteriaceae sensitive to the prescribed systemic antibiotherapy, never responsible for septicemia. Since parenteral antibiotherapy alone was able to suppress the gastrointestinal tract flora, the effects of this treatment should be considered in all trials of digestive tract decontamination.

Dose-dependent pharmacokinetics of mezlocillin in rats

The pharmacokinetics of mezlocillin were examined in rats following bolus intravenous doses of 20 or 200 mg/kg. Mezlocillin exhibited bi- or triexponential disposition profiles, and the area under the concentration-time curve increased nonproportionally with dose similar to reported findings in humans. Apparent total, renal, and nonrenal clearances and the volume of distribution at steady-state all decreased by 45 to 50% with the higher dose, and the elimination half-life was longer (8 +/- 2 versus 15 +/- 3 min). Mezlocillin exhibits low saturable binding in rat serum, ranging from 20 to 40% bound. Pharmacokinetic parameters based on free drug demonstrated dose-dependent characteristics similar to those with total drug. Use of the volume of distribution from the low dose allowed calculation of the true mean residence time. The linear relationship between dose and mean residence time from free concentrations yielded pooled Michaelis-Menten parameters. These were used as initial estimates in the simultaneous nonlinear fitting of the low- and high-dose mean free concentrations to a three-compartment model with sequential distribution and Michaelis-Menten elimination to describe the nonlinearity of mezlocillin disposition further.

Influence of coadministration on the pharmacokinetics of mezlocillin and cefotaxime in healthy volunteers and in patients with renal failure

The pharmacokinetic disposition of cefotaxime, desacetyl cefotaxime, and mezlocillin after the administration of each drug singly and in combination was examined in eight healthy volunteers and in five anuric patients with end-stage renal disease (ESRD). In the presence of ESRD, the total body clearance of cefotaxime decreased from 256.7 +/- 41.5 to 65.4 +/- 42.0 ml/min, and its elimination half-life (t1/2) increased from 1.1 to 3.6 hours as compared with healthy volunteers. Concomitant administration of mezlocillin in healthy volunteers decreased the total body clearance of cefotaxime by 42% and increased its steady-state volume of distribution. This reduction in clearance was reflected by a decrease in both renal and nonrenal clearances. In the presence of ESRD, coadministration of mezlocillin increased the t1/2 of cefotaxime to 5.8 hours. Desacetyl cefotaxime accumulated in ESRD with a prolongation of its elimination t1/2 to 18.7 hours from 1.7 hours in healthy volunteers. Desacetyl cefotaxime peak plasma concentrations occurred later with the combination regimen in the presence of ESRD. The clearance of mezlocillin was reduced and t1/2 prolonged in ESRD from 194.6 +/- 31.9 to 76.4 +/- 38.8 ml/min and 1.4 to 2.3 hours, respectively. Concomitant administration of cefotaxime did not alter the pharmacokinetics of mezlocillin. These data suggest that in the presence of normal renal function, lower doses of cefotaxime may be adequate to maintain similar cefotaxime plasma concentrations when mezlocillin is coadministered compared to when cefotaxime is given alone. Additional pharmacodynamic and clinical studies with this combination are warranted to further elucidate the clinical impact of this pharmacokinetic interaction.

A comparative analysis of aztreonam + clindamycin versus tobramycin + clindamycin or amikacin + mezlocillin in the treatment of gram-negative lower respiratory tract infections

One hundred ten patients were randomized to receive one of the following antibiotic combinations: aztreonam + clindamycin, tobramycin + clindamycin, or amikacin + mezlocillin for the treatment of lower respiratory tract infections (LRTI) caused by gram-negative bacilli. Of the 68 patients who received aztreonam + clindamycin, 60 were clinically evaluable and 50 were bacteriologically evaluable. Of the 60 clinically evaluable patients, 54 were cured and 5 were treatment failures or died during the study period. Of the 50 bacteriologically evaluable patients, 46 were cured and 3 failed to respond to therapy. Of the 26 clinically evaluable patients in the tobramycin + clindamycin group, 22 were cured and 4 either failed to respond or died during the study period. Of 18 bacteriologically evaluable patients in this group, 16 were cured and 2 failed to respond. In the amikacin + mezlocillin group, 14 of the 15 clinically and bacteriologically evaluable patients were cured, and 1 failed to respond. The most commonly isolated pathogens were Klebsiella pneumoniae, Escherichia coli, and Pseudomonas aeruginosa. The very few adverse drug reactions that were seen were transient and comparable in all three groups except for renal function parameters, which deteriorated in 6-8% of patients receiving the aminoglycoside combination. All three antibiotic combinations were similar in effectiveness and safety.

A prospective randomized trial to compare triple dose mezlocillin with triple dose cefuroxime plus metronidazole as prophylaxis in colorectal surgery

The results of a prospective randomized clinical trial to compare three dose regimens of mezlocillin with cefuroxime plus metronidazole for prophylaxis in emergency and elective colorectal surgery are reported. Severe wound infection occurred in five patients (10%) receiving mezlocillin and in four patients (7%) receiving cefuroxime and metronidazole. There were two episodes of septicaemia, each in the mezlocillin group. The total number of surgically related infections was less with cefuroxime plus metronidazole (n = 10) compared with mezlocillin (n = 17), but this was not statistically significant (P greater than 0.1).

Cefoperazone plus piperacillin versus mezlocillin plus tobramycin as empiric therapy for febrile episodes in neutropenic patients

The double beta-lactam combination of cefoperazone plus piperacillin was compared with an aminoglycoside-containing regimen of mezlocillin plus tobramycin in a prospective, randomized trial of empiric therapy for febrile neutropenic patients (neutrophils no more than 1,000/mm3). Thirty febrile episodes were treated with cefoperazone plus piperacillin and mezlocillin plus tobramycin, respectively. There was no significant difference between the two groups with respect to age, sex, pretherapy neutrophil count, and mean duration of therapy. The majority of patients had neutrophil counts of no more than 200/mm3 at the initiation of therapy. Only microbiologically and clinically documented infections were evaluated for efficacy. The cefoperazone plus piperacillin regimen appeared to have a comparable response rate with the mezlocillin plus tobramycin regimen (20 of 24 patients [83 percent] versus 16 of 23 patients [70 percent]). Gram-positive micro-organisms were seen predominantly in this study, with the cefoperazone plus piperacillin regimen achieving a bacteriologic response in 84 percent, as opposed to 60 percent for those organisms treated with the mezlocillin plus tobramycin regimen. Neither regimen was totally effective against coagulase-negative staphylococci. Eight superinfections occurred in the cefoperazone plus piperacillin arm, whereas 11 superinfections occurred in the mezlocillin plus tobramycin arm. Although fungal superinfections were most common, the number of gram-positive superinfections in the mezlocillin plus tobramycin arm exceeded those seen in the cefoperazone plus piperacillin arm. The incidence of antibiotic-related side effects was similar in the two groups. Hypokalemia was most frequently seen. Both skin rashes and nephrotoxicity were more common with mezlocillin plus tobramycin. Cefoperazone plus piperacillin was found to be effective empiric therapy in febrile neutropenic patients. This double beta-lactam combination may be particularly useful for patients who have or are at high risk for the development of renal insufficiency.

Comparison of cefoperazone and mezlocillin with imipenem as empiric therapy in febrile neutropenic cancer patients

Seventy-eight patients with cancer experienced 88 episodes of fever while neutropenic and were randomly assigned to receive empiric antibiotic therapy with cefoperazone 2 g intravenously every 12 hours and mezlocillin 4 g intravenously every six hours or imipenem/cilastatin 500 mg intravenously over 30 to 60 minutes every six hours. Within 96 hours of starting antibiotic treatment, 24 patients (57 percent) treated with cefoperazone and mezlocillin and 34 patients (74 percent) receiving imipenem/cilastatin became afebrile. One half of the patients in each arm required changes in the antibiotic regimen because of side effects, persistent fever with a site suspicious for infection, resistant organisms, or breakthrough bacteremias. Forty patients (95 percent) receiving cefoperazone and mezlocillin and 43 patients (93 percent) receiving imipenem/cilastatin recovered from the neutropenic episode. Two patients in each regimen group died of their underlying disease. One patient in the imipenem/cilastatin arm died of Pseudomonas aeruginosa sepsis. Although the two regimens are comparable in efficacy, the incidence of side effects favored the cefoperazone and mezlocillin group. No seizures or bleeding were seen in either arm; however, 19 patients (41 percent) receiving imipenem/cilastatin required pretreatment antiemetic drugs for nausea.

Cefoperazone plus mezlocillin for empiric therapy of febrile cancer patients

Two dosing regimens of cefoperazone plus mezlocillin were compared in a prospective, randomized trial for therapy of febrile cancer patients. The two regimens were 5 g mezlocillin plus 2 g cefoperazone intravenously every four hours (higher dose) or 3 g mezlocillin plus 1 g cefoperazone intravenously every four hours (lower dose). Although the overall response rate was higher with the higher dose regimen (78 percent versus 66 percent, p = 0.04), the two regimens were comparable in patients with documented infections (72 percent versus 68 percent). Likewise, the two regimens were equally effective against those infections in which the pathogen could be determined (82 percent versus 82 percent). Serum bactericidal titers of at least 1:32 against a known pathogen were associated with a higher response rate than were titers of less than 1:32, but the higher dose regimen did not result in higher serum bactericidal titers. Hypoprothrombinemia was a side effect, especially with the higher dose regimen, before prophylactic vitamin K was routinely administered to patients. Since there were no major benefits with the use of the higher dose regimen of mezlocillin plus cefoperazone, the lower dose regimen is more appropriate for routine usage.

Single, large, daily dosing versus intermittent dosing of tobramycin for treating experimental pseudomonas pneumonia

Single, large, daily aminoglycoside doses in animals are less toxic than conventional dosing, and higher drug concentrations in vitro produce more-rapid bacterial killing. Thus, we compared various aminoglycoside dosing schedules in neutropenic (n = 153) and nonneutropenic (n = 192) guinea pigs with Pseudomonas aeruginosa pneumonia. Equivalent tobramycin dosages were given: 5 mg/kg every 4 h or 30 mg/kg every 24 h. Animals were serially killed during therapy, and quantitative lung cultures were performed. Bacterial titers in lungs dropped rapidly in all tobramycin-treated animals, both neutropenic and nonneutropenic, during the initial 16 h of therapy. In nonneutropenic guinea pigs, lung titers remained constant despite continued 4-h dosing. With subsequent 24-h dosing, titers continued to drop, and by 72 h there were a significant number of animals with sterile lungs (P less than .01). In neutropenic guinea pigs given tobramycin every 24 h, bacterial regrowth occurred; thus, therapy was ineffective. Adding mezlocillin, however, suppressed regrowth; thus, combination therapy was superior (P less than .05).

Pharmacokinetics of two multiple-dose mezlocillin regimens

The pharmacokinetics of mezlocillin at two dosages were studied over the course of therapy in 12 patients receiving the drug for the treatment of infections. Patients received an initial dosing regimen of 4 g every 6 h or 5 g every 8 h, which was switched to the alternative regimen after 5 days of treatment. Both drug regimens demonstrated similar pharmacokinetic characteristics, which suggests that the reported dose-dependent elimination of mezlocillin is not an important factor in the clinical use of mezlocillin at the dosages currently used.

Multidisciplinary cost-containment program promoting less frequent administration of injectable mezlocillin

A multidisciplinary cost-containment program for promoting less frequent administration of mezlocillin injection is described. The pharmacy department and the division of infectious diseases at Hartford Hospital implemented a program through which regimens of mezlocillin 5 g every eight hours would automatically be substituted for the frequently prescribed regimen of mezlocillin 3 g every four hours. Patients with urinary-tract infections or renal insufficiency and febrile neutropenic cancer patients also received various modified regimens. Use of the modified regimens was promoted through inservice education programs and distribution of newsletters and pocket-size brochures describing the dose-dependent pharmacokinetics of mezlocillin to medical staff. The pharmacy and therapeutics committee supported the program by endorsing the use of the modified regimens and distributing periodic progress reports. Pharmacists on the nursing units were responsible for enforcing the program stipulations regarding modified dosage regimens and for reporting adverse reactions and unexpected therapeutic failures. Ten months after implementation of the program, there was better than 99% compliance with the appropriately modified mezlocillin dosage regimens. Theoretical annual cost savings based on less frequent administration of mezlocillin injection amount to more than $33,000. The multidisciplinary program described here was successful in promoting the use of modified mezlocillin dosage regimens.

Mezlocillin in pleural effusions--analysis by HPLC

Mezlocillin concentrations in the pleural fluid of six patients (42-76 years of age, suffering from cytologically confirmed malignant pleural effusions) were determined after intravenous infusion of 10 g mezlocillin. Serum and pleural fluid samples were withdrawn 15, 30, 45, 60 min, 2, 4, and 8 h post infusion. Detection of mezlocillin and its metabolites penicilloic acid and penilloic acid was carried out by means of high performance liquid chromatography (HPLC). Mezlocillin concentrations in serum increased up to 778 +/- 270 micrograms/ml after 15 min, steadily decreasing to 55 +/- 50 micrograms/ml (8 hours post infusion) comparable to the known pharmacokinetic behaviour of mezlocillin; in the pleural effusions mezlocillin levels increased up to 100 +/- 38 micrograms/ml after 1 h. This concentration was maintained throughout the following 7 h. Penicilloic levels ranged about 2-4% within serum, whereas levels below 1% were measured in the pleural fluid.

[Effect of continuous mechanical hemofiltration on the pharmacokinetics of antibiotics exemplified by mezlocillin]

Pharmacokinetics of mezlocillin (70 mg/kg as an infusion) were investigated in 8 patients with multiorgan failure undergoing continuous veno-venous haemofiltration (CVVH) due to acute renal failure (HF-group) in comparison to 8 intensive care patients with an uneffected renal system (control group). Mezlocillin concentration were studied in blood, ultrafiltrate and urine (control group). Elimination of mezlocillin was prolonged in the HF-group with a t1/2 of 170 min in comparison to 109 min in the control patients. No relevant absorption at the haemofilter membrane could be observed. With regard to our results a dose reduction and intermittend application of mezlocillin is suggested; in addition, monitoring of drug levels in critically ill patients becomes of increasing interest, especially during haemofiltration.

Azlocillin and mezlocillin concentration in human prostatic tissue

The concentrations of azlocillin and mezlocillin in human prostatic tissue obtained by transurethral resection or enucleation were measured after two 2.0-gram doses of either drug. The average plasma concentration of azlocillin and mezlocillin at time of tissue sampling was 64.9 and 36.3 micrograms/ml, respectively, and tissue concentration at the time of sampling was 22.9 micrograms/g for azlocillin and 9.4 micrograms/g for mezlocillin. The plasma/tissue concentration ratio for mezlocillin was 0.25 and for azlocillin 0.35. Concentrations of mezlocillin in tissue obtained by transurethral resection were similar to those obtained by enucleation. Azlocillin and mezlocillin in appropriate doses achieve a concentration in human prostatic tissue above the inhibitory concentration for common bacterial pathogens.

Interactions of ciprofloxacin with clindamycin, metronidazole, cefoxitin, cefotaxime, and mezlocillin against gram-positive and gram-negative anaerobic bacteria

A total of 598 clinical isolates of anaerobic bacteria were tested against ciprofloxacin by the agar dilution technique with 10(5) CFU on Wilkins-Chalgren medium. Selected strains representative of the six major genera of anaerobes relatively resistant to the quinolones were tested for interactions with ciprofloxacin in combination with clindamycin, metronidazole, cefoxitin, cefotaxime, or mezlocillin by using a checkerboard agar dilution technique. Cefotaxime-ciprofloxacin and clindamycin-ciprofloxacin were the most effective combinations, with 16% of all isolates and 44% of the Bacteroides fragilis group isolates responding synergistically to the former combination and 9% of all isolates and 37% of Peptostreptococcus isolates responding synergistically to the latter. Occasional synergy was seen with all other antibiotic combinations except for metronidazole-ciprofloxacin. Likewise, synergism was seen with all groups of anaerobes except for Fusobacterium species. Antagonistic interactions were observed only with a Peptostreptococcus intermedius strain tested against clindamycin-ciprofloxacin. These data suggest that combinations of ciprofloxacin with these agents may be useful for certain resistant anaerobic infections.

Effect of dose on pharmacokinetics and serum bactericidal activity of mezlocillin

Mezlocillin is subject to dose-dependent pharmacokinetics. Previous studies have examined the pharmacokinetic but not the pharmacodynamic aspects of this effect. The pharmacokinetic disposition of mezlocillin was determined in eight healthy volunteers in a randomized, crossover fashion after single infusions of 50 and 80 mg of mezlocillin per kg of body weight. Plasma and urine were assayed with a specific high-pressure liquid chromatography assay and analyzed by noncompartmental methods. Pharmacodynamic (bactericidal) effects were evaluated from serial serum bactericidal titers obtained after each dose by using the area under the bactericidal activity curve method. The mean mezlocillin total body clearance decreased from 203.6 +/- 36.2 ml/min after the 50-mg/kg dose to 171.7 +/- 42.1 ml/min after the 80-mg/kg dose (P, 0.01). The decreased clearance was reflected by a decrease in nonrenal clearance only (108.9 +/- 20.0 to 77.9 +/- 23.5 ml/min, respectively; P, 0.001). Mean areas under the curve for concentration in plasma versus time normalized to the 50-mg/kg dose were 314 +/- 73 and 375 +/- 64 micrograms X h/ml for the low and high doses, respectively (P, 0.01). No significant changes were observed in the steady-state volume of distribution or elimination half-life. Mean areas under the bactericidal activity curve were 100 +/- 77 and 244 +/- 143 for the 50- and 80-mg/kg doses, respectively. The decrease in mezlocillin clearance and the disproportionate increase in the area under the curve for concentration in plasma versus time, coupled with the observed prolonged bactericidal effects of the 80-mg/kg dose, lend support for administration of mezlocillin at a higher dose less frequently (e.g., 5 g every 8 h). Clinical trials with the higher-dose regimen are warranted to validate these observations.

Single dose mezlocillin versus three dose cefuroxime plus metronidazole for the prophylaxis of wound infection after large bowel surgery

A prospective, randomized, controlled trial was conducted in 116 consecutive patients undergoing colorectal surgery to compare single dose prophylaxis with mezlocillin to cefuroxime plus metronidazole in three doses. Patients were randomized to receive either a single dose of iv mezlocillin (5.0 g) or three doses of iv cefuroxime plus metronidazole at 8-hourly intervals. The first dose was given on the operating table. The overall wound infection rate in the mezlocillin treated patients (n = 54) was 30% and in the patients treated with cefuroxime plus metronidazole (n = 56) 25%. This difference is not statistically significant. When trivial wound infections were disregarded the wound infection rates were 11% and 16% respectively, which again was not statistically significant.