Editorial: enterococcus in perspective

Topical Kanamycin: an Effective Therapeutic Option in Aerobic Vaginitis

Eighty-one patients with clinical diagnosis of aerobic vaginitis (AV) were included in the study. The patients were randomized for treatment, 45 with kanamycin (100 mg vaginal ovules for 6 days, consecutively) and 36 with meclocycline (35 mg vaginal ovules for 6 days, consecutively). The patients were examined before starting the study, 1-2 days after treatment and 30 days after the end of the study. At the first follow-up the patients showed different levels of symptom reduction. Reduction in the presence of leukocytes, vaginal mucosa burning and itching were statistically significant in the group treated with kanamycin with respect to the group treated with meclocycline. Moreover, there was also reduced isolation of Enterobacteriaeae (97%) in the group treated with kanamycin versus those treated with meclocycline (76%). At the second follow-up, vaginal homeostasis (normalization of pH and presence of lactobacilli) was more evident in the kanamycin-treated group. In conclusion, our data suggest that the topical use of kanamycin could be considered a specific antibiotic for the therapy of this new pathology.

Ertapenem versus piperacillin/tazobactam for the treatment of complicated infections: a meta-analysis of randomized controlled trials

Background

Ertapenem, a new carbapenem with a favorable pharmacokinetic profile, has been approved for the treatment of complicated intra-abdominal Infections (cIAIs), acute pelvic infections (APIs) and complicated skin and skin-structure infections (cSSSIs). The aim of this study is to compare the efficacy and safety of ertapenem with piperacillin/tazobactam, which has been reported to possess good efficacy for the treatment of these complicated infections.

Methods

We performed a meta-analysis of randomized controlled trials identified in PubMed, Cochrane library and Embase that compared the efficacy and safety of ertapenem with piperacillin/tazobactam for the treatment of complicated infections including cIAIs, APIs, cSSSIs. The primary efficacy outcome was clinical treatment success assessed at the test-of-cure visit. The primary safety outcome was drug related clinical and laboratory adverse events occurred during the treatment and the post-treatment period.

Result

Six RCTs, involving 3161 patients, were included in our meta-analysis. Ertapenem was associated similar clinical treatment success with piperacillin/tazobactam for complicated infections treatment (clinically evaluable population, 1937 patients, odds ratios: 1.15, 95% confidence intervals: 0.89-1.49; modified intention to treat population, 2855 patients, odds ratios: 1.03, 95% confidence intervals: 0.87-1.22). All of secondary efficacy outcomes analysis obtained similar findings with clinical treatment success. No difference was found about the incidence of drug related adverse events between ertapenem and piperacillin/tazobactam groups.

Conclusion

This meta-analysis provides evidence that ertapenem 1 g once a day can be used as effectively and safely as recommended dose of piperacillin/tazobactam, for the treatment of complicated infections, particularly of mild to moderate severity. It is an appealing option for the treatment of these complicated infections.

Wound erysipelas following appendectomy caused by group B beta-hemolytic Streptococcus (Streptococcus agalactiae)

BACKGROUND

Case description of a patient who developed erysipelas of the surgical wound following appendectomy for acute appendicitis, and literature review of invasive group B streptococcal infections.

METHODS

A 65-year-old man with perforated appendicitis underwent urgent appendectomy and drainage. Antibiotic prophylaxis with tobramycin (100 mg) and metronidazole (500 mg) was administered. At surgery, a phlegmon was identified with free perforation of the appendix and purulent peritoneal fluid. Appendectomy, irrigation with 0.9% NaCl solution, and drainage with a Silastic closed-suction drain was performed. A literature search in all languages was performed using MEDLINE, using the search terms surgical site infection, wound infection, group B streptococcus, Streptococcus agalactiae, necrotizing fasciitis, and postoperative infection.

RESULTS

Erysipelas of the surgical wound developed on the fourth postoperative day. Intravenous penicillin and amoxicillin/clavulanic acid were administered empirically. Culture of the wound drainage identified Streptococcus agalactiae and a few colonies of Escherichia coli. The broad-spectrum antibiotic was discontinued, and a 10-day course of penicillin was completed.

CONCLUSIONS

Erysipelas of the surgical wound is unusual, and infection with group B streptococci is rare compared with infection by group A streptococci. Streptococcus agalactiae is recognized to be increasingly virulent, with an increasing predilection for bacteremic infections in healthy hosts. Although Streptococcus agalactiae remains highly susceptible to antimicrobial agents effective against gram-positive cocci, the changing epidemiology and potentially invasive nature of these infections should have clinicians alert to the possibility of infection caused by group B streptococci.

Surgical infections with enterococcus: outcome in patients treated with ertapenem versus piperacillin-tazobactam

BACKGROUND

The pathogenicity of Enterococcus in polymicrobial surgical infections is controversial. The objective of this analysis was two-fold. The impact of Enterococcus on clinical outcome was assessed in adults with complicated intra-abdominal (IAI), complicated skin and skin structure (CSSSI), or acute pelvic (PI) infection treated with ertapenem or piperacillin-tazobactam, which is more active in vitro against enterococci than ertapenem. Baseline characteristics were identified that were associated with Enterococcus infection and with treatment failure.

METHODS

This analysis included 1,558 patients treated in three randomized, triple-blind studies. Of these patients, 223 had Enterococcus in initial cultures: 125 of 623 (20%) with IAI, 28 of 529 (5%) with CSSSI, and 70 of 406 (17%) with PI. Logistic regression models were fit to assess each objective.

RESULTS

The cure rates for the two treatment groups were similar in each of the three studies, regardless of the presence or absence of Enterococcus. Cure rates for both treatment groups combined were significantly lower in patients with Enterococcus than without Enterococcus for IAI (76% [69/91] versus 87% [264/305], OR 2.3 [95% CI, 1.2-4.1], P = 0.009) and CSSSI (58% [11/19] versus 84% [241/287], OR 3.8 [95% CI, 1.5-10.0], P = 0.010); but for PI, rates were similar (96% [50/52] versus 92% [188/205], OR 0.4 [95% CI, 0.1-1.9], P = 0.220). Characteristics predictive of the presence of Enterococcus were Pseudomonas aeruginosa as a baseline pathogen for IAI, older age, and the presence of a complicating underlying disease for CSSSI, and infection severity rated moderate rather than severe for PI. The strongest predictors of treatment failure were >2 days postoperative infection at study entry for patients with IAI and older age for patients with CSSSI.

CONCLUSION

Choice of antimicrobial therapy did not affect cure rates in patients with or without Enterococcus. The strongest predictors of failure were postoperative infection at study entry in patients with IAI and older age in patients with CSSSI.

In vitro activity of ertapenem against common clinical isolates in relation to human pharmacokinetics

The in vitro activity of ertapenem against bacterial pathogens isolated from patients with moderate to severe complicated intra-abdominal, complicated skin/skin structure, acute pelvic, or complicated urinary tract infection or community acquired pneumonia was compared to ceftriaxone and piperacillin-tazobactam and related to known plasma concentrations of the three agents. Ertapenem was more potent against methicillin-susceptible Staphylococcus aureus (MSSA) than ceftriaxone and piperacillin-tazobactam and was more potent and more active than both of these agents against Enterobacteriaceae and anaerobes. Piperacillin-tazobactam was the most active agent against enterococci and Pseudomonas aeruginosa. All isolates of Enterobacteriaceae (n=1088), Streptococcus pyogenes (n=37), Streptococcus agalactiae (n=48), MSSA (n=187), Haemophilus influenzae (n=59), and Moraxella catarrhalis (n=9) were susceptible to ertapenem; < 1% of 1284 anaerobes and only 1 of 113 Streptococcus pneumoniae (a penicillin-resistant isolate) were resistant to ertapenem. The MIC value at which 90% of all Enterobacteriaceae, streptococci, MSSA, H. influenzae, M. catarrhalis, and anaerobes were inhibited (MIC90) was < or = 1 microg/ml and below the mean plasma concentration of total ertapenem following a 1 g intravenous infusion for at least 24 hours, i.e., the entire recommended dosing interval, and below the free drug concentration for at least 8 h.

Ertapenem monotherapy versus combination therapy with ceftriaxone plus metronidazole for treatment of complicated intra-abdominal infections in adults

The efficacy and safety of intravenous (IV) ertapenem, 1 and 1.5 g once a day, for treatment of adults with complicated intra-abdominal infection were compared with those of IV ceftriaxone 2 g once a day plus IV metronidazole 500 mg every 8 h. After at least 3 days of IV therapy and satisfactory clinical response, patients could be switched to oral ciprofloxacin plus metronidazole. Fifty-nine patients were randomized to receive ertapenem 1 g and 51 to receive ertapenem 1.5 g; 55 patients were randomized to each comparator group. At the test of cure, 4-6 weeks post therapy, in the 1 g cohort, 84% (26/31) of patients treated with ertapenem and 85% (35/41) with comparator therapy had a favourable clinical and microbiological assessment. Success rates in the 1.5 g cohort were 83% (22/29) and 77% (24/31) in the ertapenem and comparator groups, respectively. Drug-related adverse events were generally similar in both treatment groups. Ertapenem 1 or 1.5 g once a day followed by optional oral therapy appeared similar to combined therapy with ceftriaxone plus metronidazole with the same optional oral switch for treatment of complicated intra-abdominal infections in adults. Although not compared directly in a randomized fashion, the efficacy and safety profiles of ertapenem 1 and 1.5 g appeared comparable. Ertapenem was generally well tolerated and had an overall safety profile similar to ceftriaxone plus metronidazole.

Comparative in-vitro activities of ertapenem against aerobic bacterial pathogens isolated from patients with complicated intra-abdominal infections

The in vitro activities of ertapenem, ceftriaxone, amoxicillin-clavulanate, ampicillin-sulbactam, and piperacillin-tazobactam were compared against 1018 aerobic bacterial pathogens isolated from 531 patients with complicated intra-abdominal infection. Enterobacteriaceae accounted for 66.3% of the aerobic bacteria; Escherichia coli was the most common isolate. The ertapenem minimal inhibitory concentration was < or = 2 microg/mL for 74.6% of isolates and > or = 8 microg/mL for 21.9% (including isolates of enterococci, methicillin-resistant Staphylococcus aureus, Acinetobacter baumannii, and Pseudomonas aeruginosa). Against Enterobacteriaceae, ertapenem was the most potent and the most active drug evaluated (100% susceptible), followed by ceftriaxone (98% susceptible), piperacillin-tazobactam (96% susceptible), amoxicillin-clavulanate (80% susceptible), and ampicillin-sulbactam (64% susceptible). Piperacillin-tazobactam was the only drug evaluated with clinically useful activity against P. aeruginosa. In summary, ertapenem was highly active in vitro against many clinically important aerobic intra-abdominal bacterial pathogens, especially Enterobacteriaceae.