Antimicrobial activity of doripenem tested against prevalent Gram-positive pathogens: results from a global surveillance study (2003–2007)

Activity of ceftaroline against serotyped Streptococcus pneumoniae isolates from Europe and South Africa associated with community-acquired bacterial pneumonia (2007-08)

OBJECTIVES

To determine the activity of ceftaroline (the active metabolite of the prodrug ceftaroline fosamil), a new cephalosporin recently approved in the USA for the treatment of community-acquired bacterial pneumonia, against serotyped Streptococcus pneumoniae causing community-acquired bacterial pneumonia from Europe and South Africa.

METHODS

During 2007-08, 74 centres submitted 857 isolates of S. pneumoniae from patients with community-acquired bacterial pneumonia. These were re-identified and serotyped. MICs of ceftaroline and 12 comparators were determined by CLSI broth microdilution at a central laboratory.

RESULTS

Ceftaroline was very active against all 857 S. pneumoniae isolates (MIC(90) 0.12 mg/L). The MIC(50) for South African isolates was 0.06 mg/L compared with 0.004 or 0.008 mg/L for isolates from elsewhere. Antibiotic resistance was also higher in South Africa than other countries. Serotypes 3, 1, 7 and 11 were more susceptible to ceftaroline (MIC(90) = 0.008 mg/L) and the reference antibiotics than the population as a whole. Ceftaroline showed a biphasic MIC distribution (associated with cefuroxime susceptibility), the extent of which differed between isolate populations. Nevertheless, the highest ceftaroline MIC observed was only 0.5 mg/L (two isolates: one from the UK and one from South Africa).

CONCLUSIONS

These data from a large collection of S. pneumoniae isolates during 2007-08 from Europe and South Africa with varying serotype and antibiotic susceptibility, confirm the excellent in vitro activity of ceftaroline against S. pneumoniae causing community-acquired bacterial pneumonia in both adults and children.

[Available carbapenems: Properties and differences]

Carbapenems are β-lactam antibiotics endowed with a broader spectrum, activity and resistance to β-lactamases than other β-lactams. Due to their qualities, these antibiotics are crucial in empirical therapy, in the monotherapy of several severe hospital-acquired infections -and even that of some community-acquired infections- as well as in the directed therapy of infections due to multiresistant Gram-negative bacteria. All the available carbapenems have a similar spectrum, although there are significant differences in their antimicrobial activity, which in the long run determines the clinical indications of each carbapenem. The spectrum of ertapenem does not cover eminently nosocomial pathogens such as Pseudomonas aeruginosa and Acinetobacter spp., and hence this antibiotic is indicated in community-acquired infections requiring hospital treatment. In contrast, doripenem shows greater intrinsic activity than other carbapenems in extended spectrum beta-lactamase-producing enterobacteria and AmpC P. aeruginosa, Acinetobacter spp. and other non-fermentative and anaerobic microorganisms. Additionally, like the remaining carbapenems, doripenem has adequate pharmacokinetic characteristics and a favorable safety profile.

Doripenem: a new carbapenem antibiotic

PURPOSE

The chemistry, pharmacology, antimicrobial activity, pharmacokinetics, pharmacodynamics, efficacy and safety in humans, and formulary considerations of doripenem are reviewed.

SUMMARY

Doripenem, a member of the β-lactam class of antibiotics, is the newest addition to the carbapenems. It exhibits concentration-independent bactericidal activity against gram-positive bacteria; enteric and nonenteric gram-negative bacteria, including extended-spectrum β-lactamase-producing strains; and anaerobic pathogens. Doripenem was found to be noninferior to meropenem in the treatment of complicated intraabdominal infections and noninferior to levofloxacin in the treatment of complicated urinary tract infections including pyelonephritis and was granted marketing approval by the Food and Drug Administration for these two indications. Doripenem was also found to be noninferior to imipenem in the treatment of ventilator-associated pneumonia and noninferior to piperacillin-tazobactam in the treatment of hospital-acquired pneumonia. It has a favorable safety profile, with gastrointestinal complaints and headache being the most common adverse effects and allergic reactions the most serious adverse effects. Doripenem has a relatively low potential to induce seizures. The only known clinically relevant drug interaction is that coadministration with valproic acid may result in reductions of valproic acid serum concentrations. As with most renally eliminated antibiotics, the dose of doripenem should be adjusted according to kidney function.

CONCLUSION

Doripenem is an injectable carbapenem antibiotic with a spectrum of activity comparable to that of imipenem and meropenem. Its safety is similar to that of other carbapenems.

Doripenem: The Newest Addition to Carbapenem Antibiotics

Objective:

To review the pharmacology, pharmacokinetics, microbiology, and clinical efficacy and safety data of doripenem for the management of complicated and nosocomial infections.

Data Sources:

Literature searches were conducted using MEDLINE (1996-September 2009, week 2) and EMBASE (1996–2009, week 38) with the term doripenem. References from articles obtained from the search were evaluated for other relevant citations.

Study Selection and Data Extraction:

All articles in English evaluating the efficacy, adverse effects, pharmacology, microbiologic spectrum of activity, and pharmacokinetic profile of doripenem were selected.

Data Synthesis:

Doripenem is the newest addition to the carbapenem class of antibiotics and has been studied for a variety of indications. It is approved by the FDA for the treatment of complicated urinary tract infections and complicated intraabdominal infections. The manufacturer is also seeking an indication for the treatment of nosocomial pneumonia. Efficacy studies evaluating doripenem's use for these indications were conducted as noninferiority studies comparing doripenem with standard treatment options. Results showed that doripenem is noninferior to levofloxacin in the treatment of complicated urinary tract infections, noninferior to meropenem in the treatment of complicated intraabdominal infections, and noninferior to both piperacillin/tazobactam and imipenem/cilastatin for the treatment of nosocomial pneumonia. The adverse effect profile for doripenem is similar to that of other carbapenems, with the most commonly reported effects being headache, nausea, diarrhea, rash, and phlebitis.

Conclusions:

Doripenem has been shown to be an effective and well-tolerated carbapenem antibiotic for the treatment of complicated urinary tract infections and complicated intraabdominal infections. It has also exhibited promising results in studies evaluating its use in patients with nosocomial pneumonia.

Antibiotic resistance in urinary tract bacteria in Ouagadougou

The present study aimed to ascertain for the current situation of antimicrobial resistance of major urinary tract bacteria in Saint Camille Medical Centre. During two consecutive years, 794 urine specimens were analyzed for microorganism isolation and identification. The microorganisms were identified by conventional methods used in the centre and antimicrobial assays were performed by the NCCLS agar disk diffusion. Pathogenic microorganism's isolation was attempted for 89.04% samples. Escherichia coli (32.76%) was the most frequently isolated microorganism followed by Staphylococcus aureus (22.74%) and Klebsiella pneumoniae (10.45%). The antimicrobial screenings revealed very high antimicrobial resistance, to beta-lactams. The resistance rates recorded with E. coli were 76.64, 74.01, 25 and 74.34% for ampicillin, amoxicillin amoxicillin/clavulanic acid and trimethoprime-sulfamethoxazole, respectively. Microorganisms were still susceptible to quinolones however, attention should be paid, because, the resistance rate already reached 10% for nalidixic acid and ciprofloxacin. Periodic performance of prevalence studies is a useful tool to know the current situation of microorganisms and their resistance patterns in an institution and it helps to access the emergence and the spread of antibiotic resistance.