An observational study on the epidemiology of respiratory tract bacterial pathogens and their susceptibility to four injectable beta-lactam antibiotics: piperacillin, piperacillin/tazobactam, ceftazidime and ceftriaxone

Evaluating the best empirical antibiotic therapy in patients with acute-on-chronic liver failure and spontaneous bacterial peritonitis

BACKGROUND/AIMS

Spontaneous bacterial peritonitis (SBP) is a life-threatening complication of advanced cirrhosis. By studying the susceptibility of isolated organisms and analyzing empirical antibiotic therapy combined with clinical outcomes, we aimed to find an improved empirical antibiotic therapy by considering the individual acute-on-chronic liver failure (ACLF) grade for patients with or without sepsis.

METHODS

Clinical outcomes of 182 patients were assessed retrospectively with multivariable regression analysis. Each of the 223 isolates was individually evaluated regarding susceptibility results and intrinsic resistances.

RESULTS

Piperacillin/tazobactam had the highest antimicrobial susceptibility among monotherapies/fixed combinations, which was significantly lower than combination therapies such as meropenem-linezolid (75.3% vs. 98.5%, P < 0.001). The sensitivity of pathogens to empirical antibiotic therapy correlated with significantly lower inpatient mortality (18.9% vs. 37.0%, P = 0.018), shorter inpatient stay (16.3 ± 10.2 vs. 26.4 ± 21.0 days, P = 0.053) and shorter intensive care treatment (2.1 ± 4.5 vs. 7.9 ± 15.4 days, P = 0.016). The largest difference of mortality was observed in patients with ACLF grade 3 (54.5% vs. 73.1% [sensitive vs. non-sensitive]).

CONCLUSION

All SBP patients benefited from efficient empirical antibiotic therapy, regarding the reduced inpatient mortality and complications. For SBP patients with ACLF grade 3 without sepsis, the combination therapy with meropenem-linezolid may be suitable considering the susceptibility results and the concentration in the peritoneal cavity.

The study of prevalence and antimicrobial susceptibility of tracheal bacterial strains isolated from pediatric patients

The aim of this study was to investigate the prevalence and antimicrobial susceptibility of bacterial strains isolated from tracheal specimens obtained from pediatric patients admitted to a major children hospital in Tehran, in 2007. Tracheal specimens were cultured on the appropriate bacteriological media. Bacterial isolates were identified by standard biochemical and serological tests. Antimicrobial susceptibility testing was performed according to Clinical and Laboratory Standards Institute (CLSI) guidelines. Pseudomonas spp. was identified as the most prevalent bacterial isolate (32%) followed by Staphylococcus aureus (27.6%). Thirty strains (16%) were identified as Klebsiella spp., 18 (9.6%) as Enterobacter spp. and the rest belonged to coagolase negative Staphylococci, Streptococcus viridans, Acinetobacter spp., Escherichia coli and Neisseria spp. All Pseudomonas spp. were resistant to ampicllin, kanamycin and ceftizoxime. Staphylococcus and Klebsiella spp. showed high degree of resistance to 40% of examined antibiotics.

Bacterial susceptibilities to piperacillin/tazobactam in a tertiary care hospital: 5-year review

Several factors influence the speed of development of antibacterial resistance, among which is the amount of antibiotic consumption. During the 3-year period 1998-2000, the consumption of piperacillin/tazobactam (pip/tazo) increased by 85% in our hospital. Five years ago we conducted a comparative in vitro study to evaluate susceptibilities of microorganisms to pip/tazo. The objective of the present study was to re-evaluate in vitro susceptibilities to pip/tazo, compared to other beta-lactams, and the potential impact its increased consumption might have on its susceptibility patterns. The study was performed between November 2000 and April 2001. As in 1996, of the beta-lactams studied, pip/tazo and imipenem had the highest susceptibility rates against selected pathogens (>90% susceptibility rates). P. aeruginosa susceptibilities to both imipenem and pip/tazo were high (97% for both). P. aeruginosa susceptibilities to cefepime were lower. Despite its increased use, pip/tazo retained its initially observed high susceptibility rates for the study pathogens.