Newer Penicillins and Beta-Lactamase Inhibitors

Are We Hitting the Target?: The Effectiveness of Distinct Antibiotic Regimens in Pediatric Appendectomies

BACKGROUND

Currently, a range of different antibiotics are administered perioperatively during appendectomy surgery in the pediatric population. One reason for the lack of a uniform treatment regimen is the paucity of large studies on microbiologic data and susceptibility patterns.

METHODS

A retrospective, monocentric study on antibiotic susceptibility, including 1258 pediatric patients undergoing appendectomy from 2012 to 2020 was performed. Predictors for prolonged length of stay (LOS) and complications were determined using regression analysis, and objective criteria for broad-spectrum antibiotic regimens were identified. Simulations of the effectiveness of different antibiotic regimens against identified bacterial susceptibility results were conducted.

RESULTS

The most important predictors for prolonged LOS and an increased incidence of infectious complications are elevated preoperative C-reactive protein levels, high intraoperative severity gradings and insufficient primary antibiotic treatment. Based on our results, a simple antibiotic treatment, consisting of cefuroxime-metronidazole (C-M) or ampicillin-sulbactam (AS), is sufficient in around 85% of all patients; both options being equally efficient. In severe appendicitis, the likelihood of resistance is 31% and 32% for C-M and AS, respectively. For piperacillin-tazobactam and C-M-tobramycin, the incidence of bacterial resistance decreases to 12%. Resistance is reduced to 8% for AS-tobramycin treatment. The patient populations benefiting most from an extended antibiotic regimen are those with a high intraoperative severity grading.

CONCLUSIONS

Evidence suggests that an insufficient antibiotic regimen is associated with a prolonged LOS and a higher rate of infectious complications, justifying the expansion of a simple antibiotic regimen in cases of severe intraabdominal findings. In all other cases, a simple antibiotic treatment with AS is recommended.

Cardiac surgery in a high-risk group of patients: is prolonged postoperative antibiotic prophylaxis effective?

OBJECTIVE

In a prospective, randomized study, postoperatively prolonged antibiotic prophylaxis is evaluated in a high-risk group of patients undergoing cardiac operations. These patients had postoperative low cardiac output necessitating inotropic support and intraaortic balloon pumping.

METHODS

Between January 1991 and 1994, 53 patients were enrolled in the study (42 men, mean age 65 years). All patients received the usual perioperative (24 hours) cefazolin prophylaxis. In the study group (n = 28) a prolonged regimen of prophylaxis with ticarcillin/clavulanate was performed for 2 days and vancomycin was added in a low dose until removal of the intraaortic balloon pump. The control group (n = 25) did not receive a prolonged regimen of prophylaxis. Follow-up ended at hospital discharge.

RESULTS

Early mortality was 7 of 28 patients (25%) in the prophylaxis group and 8 of 25 patients (32%) in the control group (p = 0.397). Defined infections (pneumonia, n = 22; sepsis, n = 8; deep sternal wound infection, n = 2) occurred in 50% of the study group and 68% of the control group (p = 0.265). In all patients with septicemia, only coagulase-negative staphylococci could be isolated from the bloodstream (5 patients in the prophylaxis group vs 3 in the control group). Infectious parameters were controlled daily and did not differ significantly between groups. A total of 1158 bacteriologic tests were performed (blood cultures, n = 389; intravascular catheters, n = 208; bronchial aspirates, n = 411; intraaortic balloon pumps, n = 42; wound secretions, n = 108) showing bacterial growth in 322 (28%) without a significant difference between the groups. In the prophylaxis group, 13 intravascular catheters and intraaortic balloon pumps showed bacterial growth versus 11 in the control group. No side effects were seen.

CONCLUSIONS

In a high-risk group of patients undergoing cardiac operations, infectious outcome could not be effectively influenced by an additional and prolonged postoperative prophylaxis regimen with low-dose vancomycin and ticarcillin/clavulanate. Low-dose vancomycin did not reduce the rate of infections or colonizations of intravascular catheters with gram-positive organisms.

Efficacy of sulbactam-ampicillin for the treatment of severe diabetic foot infections

Diabetic foot infections, a frequent and serious cause of morbidity in patients with diabetes mellitus, are caused by anaerobic and aerobic bacteria. Given the fact that seriously impaired host defense factors are almost always present in these patients, bactericidal agents with a broad spectrum of antimicrobial activity are required for their treatment. Seventy-four patients with diabetic foot infections were treated with parenteral sulbactam-ampicillin (1.5 g, q.i.d.). All patients were followed-up prospectively in order to determine the efficacy and safety of sulbactam-ampicillin. The mean duration (+/- SD) of treatment in patients with osteomyelitis (n = 49) and soft tissue infections (n = 25) was 41 +/- 5 and 14 +/- 3 days, respectively. Infected limbs were amputated at various levels in 14 patients (19%). Clinical cure rates were 86% and 100% in patients with osteomyelitis and with soft tissue infection, respectively. The most frequent side effect was diarrhea and observed in 10 patients (14%). The results of the present study indicate that sulbactam-ampicillin is safe and effective in the treatment of diabetic foot infections.

Antipseudomonal penicillins

Antipseudomonal penicillins retain most of the antibacterial activity of penicillin and aminopenicillins. This group of penicillins has added activities against many gram-negative rods, including P. aeruginosa. Similar to the earlier penicillins, this group continues to be susceptible to hydrolysis by many beta-lactamases and are, therefore, not consistently active against Staphylococcus, some gram-negative rods, and certain beta-lactamase-producing gram-negative anaerobes. The ureidopenicillins, especially piperacillin, appear to have better activity against Enterococcus, Klebsiella, and P. aeruginosa than ticarcillin. The advantages over the newer cephalosporins are (1) better activity against Enterococcus, (2) more consistent activity against Clostridium, and (3) more consistent synergy with aminoglycosides. The ureidopenicillins have certain advantages over carboxypenicillins, including lower sodium load, less frequent hypokalemia, reduced platelet dysfunction, minimal dosage adjustment in patients with renal failure, and a wider spectrum of antibacterial activity, especially against Enterococcus, Pseudomonas, and Klebsiella. The utility of the antipseudomonal penicillins by themselves is limited as agents for monotherapy when the infecting organism is not known. In addition, monotherapy is not recommended in certain infections to avoid the development of resistance. When combined with a beta-lactamase inhibitor or with an aminoglycoside, however, some of the weaknesses can be overcome.

Treatment of intracranial abscesses: experience with sulbactam/ampicillin

In an open prospective study, the efficacy of sulbactam/ampicillin (50 and 100 mg/kg, respectively, qid) was evaluated in 21 patients with intracranial abscess(es). Sixteen patients had cerebral, 3 epidural, and 2 cerebellar abscesses. Multiple lesions were found in 7 patients. Sixteen patients underwent surgical intervention, others were treated with antibiotic alone. The mean duration of antibiotic therapy (+/- SD) was 48 +/- 10 days (range 26-65 days). The mean duration of follow-up after completion of therapy (+/- SD) was 6 +/- 2.4 months. All patients had at least some reduction in size of abscess(es) within 3 weeks of the initiation of therapy as monitored by computerized tomography. Seventeen patients were cured, three patients died due to causes unrelated to their infection. One patient was reoperated since no clear improvement either clinically or radiologically was observed 18 days after the first operation. Side effects of sulbactam/ampicillin were minor and transient. Results obtained in this study indicate that sulbactam/ampicillin can be used in the treatment of intracranial abscesses, alone or with surgical intervention.