Antimicrobial prophylaxis: a critique of recent trials

Quantitative determination of unbound cefoperazone in rat bile using microdialysis and liquid chromatography

Cefoperazone is a third generation cephalosporin antibiotic with a broad spectrum against gram-positive and gram-negative bacteria. It is clinically effective in the treatment of the biliary tract infections. In the present study, we utilized microdialysis sampling technique with shunt linear probe for continuous monitoring levels of cefoperazone from rat biliary ducts. The effects of berberine (a potential P-glycoprotein enhancer) pretreatment were also evaluated. Analysis of cefoperazone in the dialysates was achieved using a reversed phase RP-18 column (250 mm x 4.6 mm i.d.; particle size 5 microm) maintained at ambient temperature. The mobile phase comprised 100 mM monosodium phosphate (pH 5.5)-methanol (70:30, v/v), and the flow rate of the mobile phase was 1 ml/min. The UV detector wavelength was set at 254 nm. The area under the concentration-time curve and elimination half-life of cefoperazone were about 242.3+/-13.4 min mg/ml and 64.1+/-28.2 min, respectively. No significant effect was showed on the pharmacokinetics of cefoperazone with berberine pretreatment. This study represents a successful application of biliary microdialysis sampling technique, which is feasible for pharmacokinetic and biliary drug excretion studies.

Evolution of antimicrobial prophylaxis in cardiovascular surgery

OBJECTIVE

To examine the optimal duration of antibiotic prophylaxis in major cardiovascular surgery. MTHODSs: In the past 15 years, four prospective randomized, controlled studies, conducted by the same group of authors, compared seven prophylactic antimicrobial regimens in 2970 patients undergoing major cardiovascular surgery. In 1980/81, a 4-day cefazolin (CFZ) prophylaxis was compared with a 2-day cefuroxime (CFX) administration (n=566). In 1982/83, a 2-day CFX prophylaxis was compared with a two shot ceftriaxone (CRO) prophylaxis (n=512). In 1984/87, a 1-day CFZ prophylaxis was compared with a single shot prophylaxis of CRO (n=883). In 1994/1995, a 4 day combination of amoxicillin (AM) and netilmicin (NET) prophylaxis was compared with a single shot prophylaxis of CFX (n=1009).

RESULTS

Total infection rate varied between 4.5 and 5.7%, despite different antimicrobial regimen used and their varying duration. Wound infection rate was 1.1% (range 0.4-2.5%), sepsis rate was 0.8% (range 0.4-1.6%), pneumonia rate 2% (0.7-2.9%), urinary tract infection rate 0.4% (range 0-1.4%), and central venous catheter-related infection rate was 0.4% (0-1%). The 30-day mortality rate was 1.3% (range 0.4-2%). All these differences were not statistically significant.

CONCLUSIONS

A low infection rate (range 4.5-5.7%) occurred despite changes in duration of various prophylactic antibiotic regimen with cephalosporins of first, second or third generation. As a single shot prophylaxis could nowadays successfully be used in cardiovascular surgery, no postoperative antibiotics should be used, unless an intraoperative or a postoperative infection is documented or in presence of major perioperative complications.

Practice Management Guidelines for Prophylactic Antibiotic Use in Tube Thoracostomy for Traumatic Hemopneumothorax: the EAST Practice Management Guidelines Work Group. Eastern Association for Trauma

Multiple factors contribute to the development of posttraumatic empyema. These factors include the conditions under which the tube is inserted (emergent or urgent), the mechanism of injury, retained hemothorax, and ventilator care. The incidence of empyema in placebo groups ranges between 0 and 18%. The administration of antibiotics for longer than 24 hours did not seem to significantly reduce this risk compared with a shorter duration, although the numbers in each series were small. Most reports found a significant reduction in pneumonitis when patients received prolonged prophylactic antibiotics. This use of antibiotics might possibly be better described as presumptive therapy rather than prophylactic.

Antimicrobial prophylaxis in dermatology

Few circumstances in dermatology warrant antimicrobial prophylaxis. In cutaneous surgery postoperative infections are too infrequent and insufficiently severe to justify preventive antibiotics, except rarely. Petrolatum is as effective as, and cheaper than, topical antibiotic ointment to cover surgical wounds. In patients with numerous staphylococcal skin infections, oral clindamycin 150 mg every day for 3 months safely reduces further episodes. For recurrent cellulitis, oral penicillin or erythromycin 250 mg twice daily or monthly intramuscular benzathine penicillin decreases subsequent attacks. In patients with frequent episodes of genital or labial herpes simplex an antiviral agent such as valacyclovir 500 mg to 1 g every day is effective as a suppressant.

Prevention of sepsis in total joint arthroplasty

Because of the adoption of effective prophylactic measures such as improved operating room techniques and systemic antibiotics, the prosthetic infection rate for artificial joint procedures has been reduced to 1-2%. However, because of the devastating results and large number of prosthetic procedures, prosthetic infection remains a major challenge. Common pathogens and mechanisms of infection, methods of preventing bacterial adherence to biomaterial surfaces, and clinical preventive strategies for prosthetic infections are discussed.

Comparison of cefotaxime plus metronidazole versus cefoxitin for prevention of wound infection after abdominal surgery

In a randomized prospective stratified trial consisting of 1010 patients undergoing abdominal surgery involving the viscera, the efficacy of cefotaxime plus metronidazole was compared to cefoxitin for preventing wound infection. The efficacy of a single dose of antibiotics versus three doses over 24 hours was also evaluated. This study demonstrated that a single-dose antibiotic regimen was as effective as a multiple-dose regimen in the prophylaxis of wound infections following abdominal surgery. In addition it demonstrated that the cefotaxime plus metronidazole regimen is comparable to that of cefoxitin and is more cost-effective. It is concluded that a single dose of cefotaxime plus metronidazole provides effective prophylaxis against postoperative wound infections following abdominal surgery.

Treatment of open fractures of the foot and ankle: a preliminary report

A retrospective study was performed on 33 patients who sustained isolated open-fracture injuries to the foot and ankle. A wide variety of open-fracture injuries of the foot and ankle are documented. Of the 33 cases, only 2 became clinically infected, translating into an infection rate of 6.06%. A literature review of open-fracture injuries is presented along with the preliminary results of the retrospective study.

Antimicrobial prophylaxis for ophthalmic surgery

Preoperative, intraoperative, and postoperative antibiotic agents have been used by ophthalmic surgeons routinely as prophylaxis for postoperative endophthalmitis. The rationale for such prophylaxis and the evidence which supports its efficacy are well founded. The optimal choice of antibiotic agent--from the standpoint of efficacy, route of delivery, adverse reactions, and cost--is far less established. This review considers these issues, as well as the role of topical disinfectants, including povidone-iodine, in preoperative prophylaxis.

Bacterial wound colonization after broad-spectrum versus narrow-spectrum antibiotics

Broad-spectrum versus narrow-spectrum antibiotic prophylaxis for patients who undergo cardiac operations is variously advocated to reduce the incidence of all infections or, conversely, to prevent resistant superinfections. Previous studies of prophylaxis have shown a reduction in the incidence of staphylococcal infections with some increased resistance. We studied preoperative and postoperative wound colonization as a surrogate for infection. Among 78 patients undergoing cardiac procedures, the type of prophylaxis was allocated as follows: narrow-spectrum (nafcillin), 24 patients; midspectrum (cephapirin), 26 patients; and broad-spectrum (ceftriaxone), 28 patients. Seventeen patients who underwent other procedures received no antibiotics and served as controls. Cultures of the operative site were done preoperatively, and 3 and 6 days postoperatively. The incidence of preoperative skin colonization with staphylococci was identical (95%) in all groups. Postoperatively, more patients receiving nafcillin (48%) were culture-negative for all organisms than were either of the other groups receiving antibiotics (27% and 22%) (p < 0.05). Gram-negative bacilli were infrequent colonizers and neither did the incidence of infection with these organisms increase nor did resistance develop in any group. The infection rates were not different among the treatment groups. Thus, a narrow-spectrum antistaphylococcal penicillin may offer an advantage in terms of both prophylaxis for cardiac operations and hospital costs.

[Antibiotic prophylaxis in gynecologic surgery]

Hysterectomies are contaminated procedures; surgical wound related sepsis ranges from 10 to 25%. Several randomised controlled studies demonstrated a significant benefit with prophylactic antibiotics. The study results were more controversial for abdominal hysterectomies. Ureidopenicillins, cephamycins and other antibacterial agents active on Gram negative rods and anaerobes can be recommended as a preoperative flash at anaesthesia induction, followed by a second injection whenever the procedure duration exceeds 3 hours. In case of extended hysterectomy for cancer, broad spectrum antibiotic prophylaxis is usual; some recent studies demonstrated the efficacy of a short duration antibacterial agent use. Mastectomies are at low risk for postoperative infection. Antibacterial prophylaxis is common, especially in plastic surgery.

[Pharmacokinetic criteria of the choice of antibiotic for antibiotic prophylaxis in surgery]

The prevention of surgical infections with perioperative prophylactic antibiotics is experimentally and clinically well founded in both principle and practice. The evaluation of the role of antimicrobial agents in the success of failure of infection prophylaxis in surgery involves a discussion of both the pharmacokinetic and the pharmacodynamic properties of particular agents. A main concern in surgical prophylaxis is the relation between the respective time course of antibiotic concentrations in serum and in the tissue (wound). Several problems arise in both the measurement and the interpretation of drug concentrations in tissues and the results of this approach are still controversial. However, the knowledge of the numerous factors influencing the penetration into a tissue and the characteristics of the relative distribution of the antibiotic between the compartments inside the tissue, i.e. the vascular, interstitial and intracellular spaces, could allow a valuable approach to this problem. The concentrations of free drugs in serum are valuable predictors of the time course of unbound drug in interstitial fluid, where the bacteria are generally located. An increase in protein binding does not reduce the area under the curve (AUC) of free drug for beta lactam agents eliminated predominantly by glomerular filtration, but prolongs their elimination half life. Timing and route of administration are also important factors to consider in relation with the pharmacokinetic profile of the drug. Pharmacodynamic studies of persistent growth suppression and bactericidal activity predict that the period during which the free drug concentration exceeds the MIC is an important parameter of the efficacy of beta lactam antibiotics. In the opposite, the Cmax and/or the AUC are the major parameters of the efficacy of aminoglycosides and quinolones against Gram negative bacteria. Thus, the goal of prophylaxis with beta lactams could be to provide levels of free drug above the MIC for the whole surgical period, while the obtention of a high Cmax with a one-day therapy should be required for aminoglycosides. Further clinical trials are warranted to assess this approach.

[Antibiotic prophylaxis in vascular surgery]

Vascular surgery includes various surgical procedures and sites. Infectious risk is low but with a high functional risk and a high mortality rate. Infection risk factors are numerous. Among them the incision in the Scarpa's triangle is at the first place. Antimicrobial prophylaxis in vascular surgery has shown its efficacy whatever the agent. The second generation cephalosporins are the most logical, with a duration of administration of less than 24 hours. In case of re-operation glycopeptides have shown their efficacy.

The source of organisms in the post-prostatectomy bacteriuria of patients with pre-operative sterile urine

Ninety patients undergoing prostatectomy for benign prostatic hyperplasia (BPH) with sterile urine pre-operatively were prospectively studied for post-prostatectomy bacteriuria; 26 of 90 patients (29%) developed bacteriuria (18 of 64 after transurethral resection (TUR) and 8 of 26 after open prostatectomy), of whom 15 had pre-operative indwelling urethral catheters. The correlation of bacteriuria with several factors was studied, namely the presence of a histological inflammatory reaction within the prostatic adenoma, prostatic culture, intra-operative outgoing irrigation fluid culture, intra-operative blood culture and post-operative external meatal swab culture. The only significant correlation was between bacteriuria and meatal cultures. It was concluded that post-prostatectomy bacteriuria is probably caused by post-operative ascending infection along urethral catheters. There was not enough evidence to ascribe bacteriuria to pre-existing septic foci within the adenoma. Intra-operative contamination and infection from distant foci were also unlikely causes.

Randomized controlled study of chemoprophylaxis in transurethral prostatectomy

We studied 599 evaluable patients with benign prostatic hypertrophy at 7 urological units. Before transurethral prostatectomy the patients were randomized into 3 groups: group 1--197 patients given single-dose ceftriaxone (2 gm.), group 2--203 patients given 160/800 mg. trimethoprimsulfamethoxazole and group 3--199 controls given no antimicrobial prophylaxis. Patients with a preoperative indwelling catheter, positive urine culture, signs of active infection or preoperative antibiotic treatment were excluded. Postoperative infectious complications were demonstrated in 15 of 197 (7.6%), 25 of 203 (12.3%) and 43 of 199 (21.6%) patients in the study groups, respectively. The difference in infectious complications between groups 1 and 3 was statistically highly significant (p < 0.01) and between groups 2 and 3 it was significant (p < 0.05). Single-dose antibiotic prophylaxis proved to be useful in the prevention of serious infectious complications after transurethral prostatectomy.

Piperacillin versus cefotetan as single-dose prophylaxis in abdominal hysterectomy: a prospective, randomized, multicenter study

Five hundred and sixty-six women, consecutively admitted to nine different hospitals for elective abdominal hysterectomy, were randomized to receive a single 2 g i.v. dose of either cefotetan or piperacillin at induction of anesthesia. Five patients were excluded and 561 (287 given cefotetan and 274 given piperacillin) could be evaluated. In 10 patients (5 for each drug) the concentrations of either cefotetan or piperacillin in serum and subcutaneous tissue at the beginning and at the end of surgery and in uterus, salpinx and ovary samples, were microbiologically assessed. No significant differences could be found between cefotetan and piperacillin groups for any of the considered infectious complications (bacteremia, wound or vaginal cuff infection, pelvic cellulitis and febrile morbidity) nor for the pooled data (cefotetan group: 4.9%, piperacillin group: 5.8%, p:NS). As for the concentrations of prophylactic drugs, serum levels throughout surgery were found to be adequate.

Infection after radical abdominal hysterectomy and pelvic lymphadenectomy: prevention of infection with a two-dose peri-operative antibiotic prophylaxis

Surgical site-related infections occurred in 21% of 87 consecutive patients undergoing radical hysterectomy with pelvic lymphadenectomy (RHPL) without planned peri-operative prophylaxis. A prospective, randomized double-blind, placebo-controlled study was conducted in 68 consecutive RHPL patients. In the 32 available patients with two-dose cefuroxime and metronidazole prophylaxis no surgical site-related infections developed as opposed to a rate of 14% in the 28 patients in the placebo group (P < 0.05). In a prospective, randomized double-blind study two two-dose antibiotic prophylactic regimens were compared in 105 consecutive patients. Surgical site-related infections developed in one (2%) patient in the cefuroxime plus metronidazole group, and in six (12%) patients in the moxalactam group. This difference did not achieve statistical significance. The mean length of the postoperative hospital stay of the patients with scheduled surgical prophylaxis was significantly shorter (P < 0.01) than that of the patients operated on without surgical prophylaxis. A two-dose antibiotic regimen is recommended, because levels of antibiotics assayed in samples collected during the course of the operation indicated a rapid clearance of the antibiotics from the operative site, most likely due to the high volume of peri-operative blood loss.

Antimicrobial prophylaxis in surgery: mechanisms, misconceptions, and mischief

There is a major misconception among many surgeons about need for prolonged postoperative use of antimicrobial prophylaxis in preventing operative site infections. For example, among community hospital members of the Florida Consortium for Infection Control there is a mean duration of four days' use of intravenous antimicrobials in uninfected patients immediately following elective large bowel operations (Ehrenkranz NJ, unpublished data). Historically, much of the early work demonstrating antimicrobial prophylactic efficacy in large bowel operations was done at Jackson Memorial Hospital in Miami by Hiram Polk more than 20 years ago. A number of then surgical residents who took part in these studies, writing orders for only three doses of prophylactic drug, are now senior surgeons in active practice in Florida. Some of these surgeons currently prescribe prolonged postoperative courses of antimicrobials following large bowel surgery in uninfected patients. This is both mystifying and disconcerting.

[Perioperative antibiotic prophylaxis in maxillofacial surgery]

In surgical interventions in the maxillofacial area the intraoral approach often is chosen for technical and esthetic reasons. Because of the inevitable contamination of the surgical wounds with the facultative pathogenic mixed flora of the oral cavity, these operations are exposed to an increased risk of postoperative wound infections. Therefore, a perioperative antibiotic prophylaxis is justified. In a prospective, controlled open study in 112 patients the effect of a preoperative one-shot prophylaxis with cefuroxime was compared with that of a short-term prophylaxis for 48 hours. The low rates of postoperative infectious complications in both groups (3.5 resp. 4.5%) verify the efficacy of the perioperative antibiotic prophylaxis in head and neck surgery. For microbiological, practical and economic aspects however, the one-shot-prophylaxis should be preferred.

["Single-shot" antibiotic prophylaxis in thoracic surgery; reduction of the postoperative infection rate]

A prospective, controlled and randomised trial was started to detect the effectivity of a "single-shot" antibiotic prophylaxis in thoracic surgery using cefuroxime. Therefore 200 unselected patients, consecutively scheduled for major thoracic surgery except endoscopic procedures or mediastinoscopy were enrolled in this study and randomized into either the control group (no antibiotics perioperatively; n = 100) or the prophylaxis group (one dose of 1.5 g cefuroxime i.v. at induction of anaesthesia; n = 100). Clinical signs correlated with infection, radiological findings and the results of repeated microbiological examinations were recorded and a comparative statistical analysis was done. Compared to controls the prophylaxis group had fewer (not significant) infections of the wound, the pleural cavity and the urinary tract and fewer patients of this group showed "pronounced infiltration" in daily taken chest roentgenograms (significant), clinical signs for pneumonia and pathologic sputum findings, or new bacterial colonisation of sputum specimens on the first postoperative day, whereas bacteria, isolated from tracheal aspirates, immediately taken after intubation disappeared more often. Specimens of pleural fluid taken postoperatively were less often positive for bacteria. Fewer patients were treated with antibiotics in the postoperative course and the courses were shorter in the prophylaxis group compared to controls. Considering the risk factor "positive microbiological culture" in preoperative tracheal aspirates, patients of the prophylaxis group showed much more seldom new radiological "infiltration" (statistically highly significant) and, in addition, had lower white blood cell counts (significant) and lower mean maximal body temperatures. The results of our trial confirm the preventive effect of "single-shot" antibiotic prophylaxis in thoracic surgery against infections.

A prospective randomized double-blind trial of ceftriaxone versus no treatment for abdominal hysterectomy

The value of preoperative prophylactic parenteral treatment with ceftriaxone at elective abdominal hysterectomy was investigated in a prospective, randomized, double-blind study, in which 157 women participated, 77 in the antibiotic group and 80 in the control group. Increased febrile morbidity and a significant preponderance of women with urinary tract infections were observed in the untreated group, whereas there was no significant difference between the two groups regarding wound infections or infiltration at the top of the vagina. We find no indication for routine prophylactic use of antibiotics at elective abdominal hysterectomy.

Oral prophylaxis with fosfomycin trometamol in transurethral prostatectomy and urological maneuvers: literature review and personal experience

In the literature there are three comparative and two open studies in which 1,395 patients received 3 g of fosfomycin trometamol per os 12 or three hours before and 24 hours after surgery: 625 patients received control substances or placebo. In the comparative studies the incidence of postoperative bacteriuria in patients treated with fosfomycin trometamol ranged from 2.9 to 7.6% at one week and from 1.2 to 3.2% at two to four weeks follow-up, and was lower than in patients treated with reference drugs or placebo. In the open study, postoperative bacteriuria ranged from 2.9 to 6.0% at one week follow-up. In our open study, 70 patients were evaluable. Four out of 70 (5.7%) developed fever > or = 38 degrees C, with positive urine culture, during the first three postoperative days. At two weeks follow-up another 5.7% showed a symptomatic urinary tract infection with a cumulative infection rate of 11.4%. In all cases, the bacteria were resistant to fosfomycin trometamol. A low incidence, 4.2%, of side effects, mainly related to the gastrointestinal tract, was observed. Fosfomycin trometamol proved to be effective with the advantage of no risk of cross resistance, practical pharmaceutical formulation with good patient compliance, good safety profile with few side effects and a satisfactory cost/benefit ratio.

Prophylactic use of antimicrobial agents in adult patients

The prophylactic use of antimicrobial agents is recommended for prevention of numerous infections, including tuberculosis, endocarditis, rheumatic fever, recurrent cellulitis and lymphangitis in patients with lymphedema, meningococcal meningitis, and bite wounds. In addition, the prophylactic use of antimicrobial agents has proved effective in certain surgical procedures such as various abdominal operations, hysterectomy, and major operations that involve the head and neck. Except for oral bowel preparations, antimicrobial prophylaxis should be limited, in general, to the operative period. Prolonged perioperative prophylaxis has not been shown to enhance effectiveness and may result in increased toxicity, resistant superinfections, and inflated costs. The investigation of antimicrobial prophylaxis necessitates adequate evaluation of the potential advantages and disadvantages in a prospective, double-blind fashion.

Potential inroads to reducing hospital-acquired staphylococcal infection and its cost

Staphylococci are still the most common agents implicated in hospital-acquired infections. In addition to Staphylococcus aureus, coagulase-negative staphylococci have attracted widespread interest, since they have emerged as the most frequent pathogen in foreign-body related infections. The emergence of methicillin-resistant S. aureus has resulted in increasing use of potentially toxic and extremely expensive antibiotics. To prevent hospital-acquired staphylococcal infections only control measures proven to be effective should be implemented and the cost of infection control procedures should always be considered. Handwashing as the simplest, cheapest, and still the most effective measure should constantly be stressed. In this article, effective procedures for the prevention of hospital-acquired staphylococcal infections are summarized, with special emphasis on cost-saving measures.

Role of quinolones in surgical prophylaxis

The general principles involved in the use of chemoprophylaxis in surgery, the selection of patients at risk, and the choice of antibiotic agents are reasonably well established. While a good deal of data exist regarding commonly used prophylactic regimens, very little data are available on the role of quinolones in surgical prophylaxis. The literature dealing with this area is reviewed, and studies on the use of quinolones in biliary, colorectal, urologic, orthopedic and vascular surgery are discussed. The data suggest that generally the quinolones are as efficacious as the other antibiotics with which they were compared, and in the case of urologic surgery the results using quinolones were better than those in non-treated controls. Single-dose prophylaxis was regularly shown to be as effective as multiple dose regimens. Further clinical trial data are necessary before any firm conclusions can be drawn regarding the role of quinolones in surgical prophylaxis.

Antibiotic prophylaxis in non-cardiac thoracic surgery. A double-blind study of penicillin vs. cefuroxime

Patients referred for elective pulmonary surgery were enrolled in a prospective, randomized, double-blind study comparing the prophylactic efficacy of four-dose regimens of penicillin-G 5 million IU and cefuroxime 1.5 g. the first dose given immediately preoperatively. The treatment groups were comparable preoperatively with regard to all tested demographic factors. No significant intergroup difference was found concerning postoperative empyema, wound infection, septicaemia, pneumonia or fever of unknown origin, or any other complication or parameter tested in connection with pulmonary surgery. No side effects were observed, and no effects on the patients normal bacterial flora. Penicillin is recommended as prophylaxis in this type of surgery.

Meta-analysis of randomized controlled trials of antibiotic prophylaxis in abdominal hysterectomy

The value of antibiotic prophylaxis in abdominal hysterectomy was reviewed by meta-analysis. Two independent literature searches (1986-1988) yielded 150 relevant papers, however, only 17 (11.3%) papers met our inclusion criteria. The selected papers described prospective, randomized, blinded, placebo-controlled studies of patients undergoing elective abdominal hysterectomy. In 14 of 17 (82%) trials, first- or second-generation cephalosporins were used. Results pooled confirm that antibiotic prophylaxis will reduce infectious morbidity following elective abdominal hysterectomy. Hospital stay is little affected and significant levels of infectious morbidity remain.

Changing surgical antimicrobial prophylaxis practices through education targeted at senior department leaders

Prescribing antibiotics for perioperative prophylaxis in common surgical procedures presents an ideal target for educational intervention. In this situation, antibiotics are often used inappropriately, with consequent excess expense and risk of morbidity. We developed an educational intervention aimed at the choice and appropriate dosing of antibiotics for the prophylaxis of cesarean sections. Person-to-person educational messages targeted at authoritative senior department members were supplemented by brief reminders on a structured antibiotic order form. Time-series analyses were conducted on 34 months of antibiotic use data for 2,783 cesarean sections to estimate the trend of magnitude and significance of discontinuities associated with the start of the program. Prior to the intervention, 95% of sections receiving prophylaxis were given cefoxitin and 3% were given cefazolin. After the intervention, these proportions were reversed, with the shift in use occurring immediately after the intervention (p less than .001). Two years after the intervention, virtually all patients undergoing cesarean sections who receive antibiotic prophylaxis are given cefazolin. Savings from this change alone accounted for over $26,000 each year, or $47.36 per patient-day of prophylaxis. Substantial changes in prescribing practices for routine procedures can be accomplished through the implementation of a coordinated educational program that enlists influential senior staff members in a department in which policy-making is highly centralized, coupled with a structured educational ordering system. Lasting improvements in clinical practices may be brought about by means that are noncoercive, inexpensive and well-accepted by medical staff.

Antimicrobial prophylaxis for open heart operations

Between 1986 and 1988, 450 adults undergoing coronary artery bypass, cardiac valve replacement, or both were enrolled into a prospective, randomized, comparative trial of cephalothin versus cefamandole as perioperative prophylaxis. They were assessed during their hospitalization and at 6 weeks and 6 months after discharge for postoperative infectious complications. Eleven patients had major postoperative infections including 5 with sternal wound infections (three bacteremic), 6 with bacteremia, 1 with prosthetic valve endocarditis, and 3 with severe venous donor graft site infections. Eight major infections occurred in patients receiving cephalothin prophylaxis and three in patients receiving cefamandole, with all five sternal wound infections occurring in the cephalothin group. Postoperative pathogens responsible for the major infections included gram-negative aerobes in 5 patients, Staphylococcus aureus in 4, and Staphylococcus epidermidis in 2. Preoperative colonizing staphylococcal isolates were not predictive of postoperative staphylococcal pathogens. Although there was no statistically significant difference in rate of major postoperative infectious complications using either cephalothin or cefamandole prophylaxis, there was a trend in favor of cefamandole. Gram-negative aerobes are becoming increasingly important pathogens in this setting.

Inoculum effect on growth-delay time of oxacillin-resistant strains of Staphylococcus aureus and Staphylococcus epidermidis exposed to cefamandole, cefazolin, and cefuroxime

Cephalosporins have been recommended as prophylactic antibiotics in patients undergoing cardiovascular surgery. The major function of these antibiotics is to protect patients against Staphylococcus aureus and Staphylococcus epidermidis infections. The lowest inoculum amount responsible for infection during surgery is unknown but is probably low. To determine the comparative activities of cefazolin, cefuroxime, and cefamandole against S. aureus and S. epidermidis for prophylactic purposes, we selected five strains of S. aureus and S. epidermidis that presented homogeneous resistances to oxacillin. A continuously monitored turbidimetric method was used to evaluate cultures with variable inoculum sizes ranging from 10(6) to 1 CFU/ml and exposed to cefazolin, cefuroxime, and cefamandole at concentrations of 0.5, 1, 2, 4, 8, 16, and 32 micrograms/ml. Growth was defined as an increase of 0.1 optical density unit. The relationship between the time required for growth, the antibiotic concentration, and the initial bacterial density showed that cefamandole was more active than cefazolin, which, in turn, was revealed to be more active than cefuroxime against S. aureus and S. epidermidis.

Prophylactic chemotherapy with fosfomycin trometamol versus placebo during transurethral prostatic resection

A prospective randomized controlled double-blind study was performed on 61 patients undergoing transurethral resection of the prostate. The first group of 31 patients received 3 g fosfomycin trometamol p.o. each on the evening before and after the operation; the second group of 30 patients received a placebo. Urine samples were taken by catheter puncture 24 and 48 h postoperative. After removal of the catheter (day 5) the first midstream urine was collected for culture, and from that moment on all patients were treated with a nitrofurantoin derivative for two weeks. Although the same strict antiseptic measures were standard practice for both groups, the incidence of early postoperative urinary tract infections was significantly lower for the fosfomycin trometamol group (0/31 versus 6/30 in placebo recipients). None of the patients suffered from a major symptomatic or complicated infection. There were no side effects registered.

Meta-analysis of randomized, controlled clinical trials of antibiotic prophylaxis in biliary tract surgery

In this study all available clinical trials of antibiotic prophylaxis in biliary tract surgery, published from 1965 to 1988, were examined. Results of 42 randomized, controlled trials (4129 patients), in which a group of patients treated with antibiotics was compared with a group of patients not treated with antibiotics, were pooled. Wound infection rates in the control groups range from 3 to 47 per cent and are 15 per cent overall. The overall difference in infection rates is 9 per cent in favour of antibiotic treatment (95 per cent confidence interval 7-11 per cent), while the common odds ratio is 0.30 (95 per cent confidence interval 0.23-0.38). Subgroup meta-analysis showed a significant stronger protective effect in high risk patients, while the timing of wound inspection (i.e. early in hospital or late at follow-up) markedly influenced the treatment effect reported. Comparison of wound infection rates in patients treated with first generation versus second or third generation cephalosporins (11 trials, 1128 patients), as well as single-dose versus multiple-dose regimens (15 trials, 1226 patients) did not reveal any significant effect (P greater than 0.05) in each trial separately as well as in the overall comparison. The results indicate that there is evidence against further use of no-treatment controls and that the choice of treatment regimen can largely be made on the basis of cost.

Prophylactic chemotherapy with fosfomycin trometamol during transurethral surgery and urological manoeuvres. Results of a multicentre study

The aim of the present open prospective study is to evaluate the efficacy and safety profile of fosfomycin trometamol in the chemoprophylaxis of urinary tract infections following transurethral diagnostic and/or therapeutic manoeuvres. 712 patients were enrolled in 72 urological surgical centres. All the enrolled patients received an initial dose of fosfomycin trometamol (Monuril sachet containing 3 g of active drug in powder) 3 h before and a second dose 24 h after the transurethral manoeuvres. Clinical and microbiological examinations were carried out before the intervention, and then on the second and seventh days after the manoeuvres. 94 patients with positive baseline tests were excluded from the microbiological follow-up for non-compliance with the main inclusion criteria. Out of 618 patients with sterile urine or with bacteriuria less than 10(5) ml on baseline screening, 20 (3.2%) developed UTI on the second day and 22 (3.6%) on the seventh day after treatment. Clinical follow-up is in agreement with these microbiological data. Overall, a total of 24 side effects were observed (3.3%), 16 of which were associated with Monuril treatment. The results of this open study agree with the preliminary observations in the controlled studies.

Antibiotic pressure and nosocomial disease

Nosocomial infection control programs of various types have been implemented in human hospitals since the staphylococcal pandemic of the 1950s. The prevalence of hospital infections is expected to increase in veterinary medicine with the advent of sophisticated invasive monitoring techniques, lengthier patient hospital stays, and the widespread use of antimicrobial agents. In order to monitor and control nosocomial infection outbreaks, the hospital staff must make strategic measures a priority. We propose the establishment of a nosocomial infection control committee, especially at the larger teaching and referral centers, to oversee such activities as hospital and personnel hygiene protocols, patient handling, antisepsis of surgical and critical care instruments, and surveillance. We have described a hospital pharmacy antibiotic restriction policy similar to those used with success in several human hospitals. It is apparent that the careless use of antibiotics adds significantly to the emergence of resistant hospital microflora and predisposes hospitalized patients to nosocomial infections. Judicious use of antibiotics not only helps to curtail such risks and lower health costs but encourages the clinician to fully evaluate his or her therapeutic rationale. As with any new program, continued staff education is the paramount requirement for its success.

Biofilms, bacteria and bladder catheters. A clinical study

Biofilms were present on 16 of 33 urethral catheters examined. In 11 cases the catheter carried a different microbial flora from that of the bladder urine. The length of time the catheter was in situ did not influence biofilm formation, and all types of materials tested supported biofilm growth. Biofilms were seen on 2 of the 7 catheters where prophylactic antibiotics had been used.

National study on the utilization of prophylactic antibiotics in surgery, Belgium, 1986

During the last week of May 1986, a 1-week prospective study on antibiotic utilization in surgical patients was held in 104 (42%) of the 247 Belgian acute care hospitals. All surgical patients with a post-operative stay of at least 3 days were studied, involving 3112 patients. Each patient was observed for 7 days, starting from the day before surgery. Antibiotics were administered to 71.9% of all patients; 21.9% received therapeutic antibiotics and 52.9% prophylactic antibiotics; 2.9% received both. Of the 1285 patients undergoing a surgical procedure with no indication for antimicrobial prophylaxis, 50.7% nevertheless received prophylaxis; 92.8% of patients with a generally recognized indication for prophylaxis received antibiotic prophylaxis. Less than one fifth (17.1%) of all prophylactic courses were stopped on the day of the intervention whilst 26.3% were continued up to the fifth post-operative day or beyond. The most frequently prescribed drugs for this indication included first and second generation cephalosporins and nitroimidazoles. The number of different generic drugs utilized per hospital ranged from 1 to 18 (mean: 7.7).

Intra-abdominal versus intramuscular application of two ampicillin preparations in cows

Plasma ampicillin concentrations were determined in a cross-over trial involving five cows after single intramuscular or intra-abdominal administration of sodium ampicillin (10 mg/kg) and ampicillin anhydrate (40 mg/kg). After injection of sodium-ampicillin, high plasma concentrations were reached within 10 min; Cmax following intramuscular injection was 9.1 micrograms/ml and after intra-abdominal injection 7.5 micrograms/ml. Urine concentrations of ampicillin were low after 24 h (1-1.5 micrograms/ml). No significant changes in blood leucocyte numbers, plasma zinc, iron or fibrinogen levels occurred. After injection of ampicillin anhydrate 1 h elapsed before maximum plasma levels were obtained; Cmax was 5.4 micrograms/ml after intramuscular and 6.7 micrograms/ml after intra-abdominal administration. Urine concentrations were very high (238-303 micrograms/ml) after 24 h and stayed above 1 microgram/ml for 6 days. After administration of ampicillin anhydrate a significant increase in blood neutrophils (P less than 0.01) and a significant increase in plasma fibrinogen was measured after intramuscular and intra-abdominal injection (P less than 0.05). A significant decrease in plasma zinc concentration after intra-abdominal injection occurred (P less than 0.05). In abdominal surgery in cows in which contamination cannot be prevented, and practical objections inhibit preoperative administration, intramuscular or intra-abdominal administration during surgery of sodium ampicillin seems justified. Ampicillin anhydrate should not be used intra-abdominally.

Hemodynamic changes after nafcillin administration during coronary artery bypass surgery

The hemodynamic response to nafcillin administration was studied in 45 patients with good left ventricular function and no known history of hypersensitivity to penicillin during coronary artery bypass grafting (CABG). Group I (15 patients) received 1 gram of nafcillin in 10 mL of saline as an intravenous (IV) bolus, group II (15 patients) received 1 gram of nafcillin in 50 mL of saline as a slow IV infusion over 15 minutes, and group III (15 patients) did not receive nafcillin. Hemodynamic variables and plasma histamine and catecholamine levels were measured before and after nafcillin administration, after 500 mg of CaCl2, and after 0.1 mg of phenylephrine. Bolus nafcillin administration produced profound hypotension secondary to vasodilatation with significant increases in cardiac index and decreases in systemic and pulmonary vascular resistances. Cardiac index increased from 3.15 +/- 0.3 L/min/m2 to 5.75 +/- 0.25 L/min/m2 (P less than 0.005) one minute after nafcillin administration, and remained at 5.1 +/- 0.35 L/min/m2 after administration of CaCl2 (P less than 0.005). All hemodynamic parameters returned toward control values after administration of 0.1 mg of phenylephrine, IV. Plasma epinephrine, norepinephrine, and histamine levels increased more than 100%. In group II, cardiac index increased, while systemic and pulmonary vascular resistances and mean arterial pressure decreased. However, these changes were less significant than those found in group I.(ABSTRACT TRUNCATED AT 250 WORDS)

Antimicrobial prophylaxis of experimental endocarditis caused by Staphylococcus epidermidis

Using two different strains of Staphylococcus epidermidis in a rat model of experimental endocarditis, we examined the prophylactic efficacy of cefamandole (200 mg/kg/dose), cefazolin (200 mg/kg/dose), nafcillin (200 mg/kg/dose), and vancomycin (20 mg/kg/dose). In vitro susceptibility testing demonstrated that both test strains were resistant to methicillin and cefazolin and susceptible to cefamandole and vancomycin. A 10(6) cfu inoculum was used for both strains, an inoculum which produced endocardial infections in greater than 90% of rats. Initial doses of each antibiotic were given 45 min to 1 h prior to bacterial challenge and were followed by six additional doses of each antibiotic administered subcutaneously every 6 h. The efficacy rates of cefamandole (84.0%) and cefazolin (70.8%) were exactly the same for rats infected with either S. epidermidis strain. Similar efficacy rates were seen in rats infected with either strain and treated with vancomycin (94.4% and 86.7%). Unlike the other three drugs, the efficacy of nafcillin was quite different in rats challenged with the two strains (62.5% and 38.5%, p = 0.19). It appears that cefamandole and cefazolin may have considerable prophylactic efficacy against certain infecting strains of methicillin-resistant, coagulase-negative staphylococci when relatively large doses of cephalosporins are administered subcutaneously in this animal model.

Bladder drainage: a survey of practices among gynaecologists in the British Isles

All 2836 members and fellows of the Royal College of Obstetricians and Gynaecologists were circulated with a questionnaire concerning catheterization practices; 1229 replies were received, an overall response rate of 43%; the response rate from practitioners of consultant and senior registrar status was 67%. Practices varied considerably, some aspects of management apparently relating to the age or experience of the surgeon, some to their level of interest or surgical commitment in gynaecological urology, and some showing regional variation. Of the 960 respondents in active gynaecological practice, 84-93% (depending on the operation) drained the bladder before routine abdominal procedures, 52-54% (depending on the route) drained the bladder before incontinence surgery, and 62-70% routinely used continuous bladder drainage for periods between 1 and 12 days following these procedures. Overall, 51% of respondents preferred urethral, and 39% suprapubic catheters for postoperative bladder drainage; this showed a marked regional- and experience-related variation. Prophylactic antibiotics were used by 32% of gynaecologists overall, and a wide variety of other measures were employed in the management of catheter-associated infection, and other problems of catheter management.