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Assessment of combination therapy in BALB/c mice injected with carbapenem-resistant Enterobacteriaceae strains.

Salloum NA, Kissoyan KA, Fadlallah S, Cheaito K, Araj GF, Wakim R, Kanj S, Kanafani Z, Dbaibo G, Matar GM - Front Microbiol (2015)

Bottom Line: As such, the qRT-PCR revealed a significant decrease of transcript levels in all isolates upon using rifampicin or tigecycline, singly or in combination with colistin.In vivo assessment showed that all combinations used were effective against isolates harboring bla CTXM-15, bla OXA-48, and bla NDM-1.Conversely, the most significant combination against the isolate harboring bla KPC-2 gene was colistin with either carbapenem, fosfomycin, or kanamycin.

View Article: PubMed Central - PubMed

Affiliation: Department of Experimental Pathology, Immunology and Microbiology, Center for Infectious Diseases Research, Faculty of Medicine, American University of Beirut Beirut, Lebanon.

ABSTRACT
Monotherapeutic options for carbapenem resistant infections are limited. Studies suggest that combination therapy may be associated with better outcomes than monotherapies. However, this is still controversial. This study assessed, the efficacy of combination therapy against carbapenem resistant Enterobacteriaceae harboring singly various extended spectrum beta lactamase or carbapenemase encoding genes. Thus, four isolates harboring either bla CTXM-15, bla CTXM-15 and bla OXA-48, bla NDM-1, or bla KPC-2 genes were selected for testing. Minimal inhibitory concentration was determined by broth dilution method. Gene transcript levels on single and combined treatments were done in vitro and in vivo by qRT-PCR. Assessment of treatments was done in BALB/c mice according to a specific protocol. As such, the qRT-PCR revealed a significant decrease of transcript levels in all isolates upon using rifampicin or tigecycline, singly or in combination with colistin. However, variable levels were obtained using colistin singly or in combination with meropenem or fosfomycin. In vivo assessment showed that all combinations used were effective against isolates harboring bla CTXM-15, bla OXA-48, and bla NDM-1. Conversely, the most significant combination against the isolate harboring bla KPC-2 gene was colistin with either carbapenem, fosfomycin, or kanamycin. As a conclusion, combination therapy selected based on the type of carbapenemase produced, appeared to be non-toxic and might be effective in BALB/c mice. Therefore, the use of a rationally optimized combination therapy might lead to better results than monotherapy, however, clinical trials are needed for human consumption.

No MeSH data available.


Related in: MedlinePlus

Gene transcript levels in vivo for the genes blaCTX-M-15, blaCTX-M-15 and blaOXA-48, blaNDM-1, blaKPC-2 in their respective isolates IMP33, IMP53, IMP216, and KPC treated with Colistin, Colistin+Meropenem, or Colistin+Fosfomycin at the MIC levels. IMP33: colistin: 5.40 (p = 0.053), colistin and meropenem: 1.38 (p = 0.038), colistin and fosfomycin: 0.19 (p = 0.024). IMP53 (CTX-M-15): colistin: 0.04 (p = 0.038), colistin and meropenem: 0.41 (p = 0.029), colistin and fosfomycin: 0.19 (p = 0.096). IMP53 (OXA-48): colistin: 3.53 (p = 0.221), colistin and meropenem: 0 (p = 0.041), colistin and fosfomycin: 0 (p = 0.049). IMP216: colistin: 2.22 (p = 0.043), colistin and meropenem: 3.10 (p = 0.021), colistin and fosfomycin: 1.44 (p = 0.052). KPC: colistin: 0.53 (p = 0.026), colistin and meropenem: 1.49 (p = 0.980), colistin and fosfomycin: 0.75 (p = 0.042). PC, positive control; Col, colistin; Mer, meropenem; Fos, fosfomycin.
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Figure 2: Gene transcript levels in vivo for the genes blaCTX-M-15, blaCTX-M-15 and blaOXA-48, blaNDM-1, blaKPC-2 in their respective isolates IMP33, IMP53, IMP216, and KPC treated with Colistin, Colistin+Meropenem, or Colistin+Fosfomycin at the MIC levels. IMP33: colistin: 5.40 (p = 0.053), colistin and meropenem: 1.38 (p = 0.038), colistin and fosfomycin: 0.19 (p = 0.024). IMP53 (CTX-M-15): colistin: 0.04 (p = 0.038), colistin and meropenem: 0.41 (p = 0.029), colistin and fosfomycin: 0.19 (p = 0.096). IMP53 (OXA-48): colistin: 3.53 (p = 0.221), colistin and meropenem: 0 (p = 0.041), colistin and fosfomycin: 0 (p = 0.049). IMP216: colistin: 2.22 (p = 0.043), colistin and meropenem: 3.10 (p = 0.021), colistin and fosfomycin: 1.44 (p = 0.052). KPC: colistin: 0.53 (p = 0.026), colistin and meropenem: 1.49 (p = 0.980), colistin and fosfomycin: 0.75 (p = 0.042). PC, positive control; Col, colistin; Mer, meropenem; Fos, fosfomycin.

Mentions: The in vivo assessment of the effect of combination therapy on gene transcript levels by qRT-PCR revealed, in most of the isolates, different responses when compared to their respective in vitro responses. Moreover, when colistin was used singly or in combination with meropenem or fosfomycin in vivo, the qRT-PCR showed variable gene transcript levels for the respective ESBL and carbapenemase encoding genes within the in vivo samples. The transcript levels of the ESBL and carbapenemase encoding genes, for the respective isolates harboring the various genes are shown in Figure 2.


Assessment of combination therapy in BALB/c mice injected with carbapenem-resistant Enterobacteriaceae strains.

Salloum NA, Kissoyan KA, Fadlallah S, Cheaito K, Araj GF, Wakim R, Kanj S, Kanafani Z, Dbaibo G, Matar GM - Front Microbiol (2015)

Gene transcript levels in vivo for the genes blaCTX-M-15, blaCTX-M-15 and blaOXA-48, blaNDM-1, blaKPC-2 in their respective isolates IMP33, IMP53, IMP216, and KPC treated with Colistin, Colistin+Meropenem, or Colistin+Fosfomycin at the MIC levels. IMP33: colistin: 5.40 (p = 0.053), colistin and meropenem: 1.38 (p = 0.038), colistin and fosfomycin: 0.19 (p = 0.024). IMP53 (CTX-M-15): colistin: 0.04 (p = 0.038), colistin and meropenem: 0.41 (p = 0.029), colistin and fosfomycin: 0.19 (p = 0.096). IMP53 (OXA-48): colistin: 3.53 (p = 0.221), colistin and meropenem: 0 (p = 0.041), colistin and fosfomycin: 0 (p = 0.049). IMP216: colistin: 2.22 (p = 0.043), colistin and meropenem: 3.10 (p = 0.021), colistin and fosfomycin: 1.44 (p = 0.052). KPC: colistin: 0.53 (p = 0.026), colistin and meropenem: 1.49 (p = 0.980), colistin and fosfomycin: 0.75 (p = 0.042). PC, positive control; Col, colistin; Mer, meropenem; Fos, fosfomycin.
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Figure 2: Gene transcript levels in vivo for the genes blaCTX-M-15, blaCTX-M-15 and blaOXA-48, blaNDM-1, blaKPC-2 in their respective isolates IMP33, IMP53, IMP216, and KPC treated with Colistin, Colistin+Meropenem, or Colistin+Fosfomycin at the MIC levels. IMP33: colistin: 5.40 (p = 0.053), colistin and meropenem: 1.38 (p = 0.038), colistin and fosfomycin: 0.19 (p = 0.024). IMP53 (CTX-M-15): colistin: 0.04 (p = 0.038), colistin and meropenem: 0.41 (p = 0.029), colistin and fosfomycin: 0.19 (p = 0.096). IMP53 (OXA-48): colistin: 3.53 (p = 0.221), colistin and meropenem: 0 (p = 0.041), colistin and fosfomycin: 0 (p = 0.049). IMP216: colistin: 2.22 (p = 0.043), colistin and meropenem: 3.10 (p = 0.021), colistin and fosfomycin: 1.44 (p = 0.052). KPC: colistin: 0.53 (p = 0.026), colistin and meropenem: 1.49 (p = 0.980), colistin and fosfomycin: 0.75 (p = 0.042). PC, positive control; Col, colistin; Mer, meropenem; Fos, fosfomycin.
Mentions: The in vivo assessment of the effect of combination therapy on gene transcript levels by qRT-PCR revealed, in most of the isolates, different responses when compared to their respective in vitro responses. Moreover, when colistin was used singly or in combination with meropenem or fosfomycin in vivo, the qRT-PCR showed variable gene transcript levels for the respective ESBL and carbapenemase encoding genes within the in vivo samples. The transcript levels of the ESBL and carbapenemase encoding genes, for the respective isolates harboring the various genes are shown in Figure 2.

Bottom Line: As such, the qRT-PCR revealed a significant decrease of transcript levels in all isolates upon using rifampicin or tigecycline, singly or in combination with colistin.In vivo assessment showed that all combinations used were effective against isolates harboring bla CTXM-15, bla OXA-48, and bla NDM-1.Conversely, the most significant combination against the isolate harboring bla KPC-2 gene was colistin with either carbapenem, fosfomycin, or kanamycin.

View Article: PubMed Central - PubMed

Affiliation: Department of Experimental Pathology, Immunology and Microbiology, Center for Infectious Diseases Research, Faculty of Medicine, American University of Beirut Beirut, Lebanon.

ABSTRACT
Monotherapeutic options for carbapenem resistant infections are limited. Studies suggest that combination therapy may be associated with better outcomes than monotherapies. However, this is still controversial. This study assessed, the efficacy of combination therapy against carbapenem resistant Enterobacteriaceae harboring singly various extended spectrum beta lactamase or carbapenemase encoding genes. Thus, four isolates harboring either bla CTXM-15, bla CTXM-15 and bla OXA-48, bla NDM-1, or bla KPC-2 genes were selected for testing. Minimal inhibitory concentration was determined by broth dilution method. Gene transcript levels on single and combined treatments were done in vitro and in vivo by qRT-PCR. Assessment of treatments was done in BALB/c mice according to a specific protocol. As such, the qRT-PCR revealed a significant decrease of transcript levels in all isolates upon using rifampicin or tigecycline, singly or in combination with colistin. However, variable levels were obtained using colistin singly or in combination with meropenem or fosfomycin. In vivo assessment showed that all combinations used were effective against isolates harboring bla CTXM-15, bla OXA-48, and bla NDM-1. Conversely, the most significant combination against the isolate harboring bla KPC-2 gene was colistin with either carbapenem, fosfomycin, or kanamycin. As a conclusion, combination therapy selected based on the type of carbapenemase produced, appeared to be non-toxic and might be effective in BALB/c mice. Therefore, the use of a rationally optimized combination therapy might lead to better results than monotherapy, however, clinical trials are needed for human consumption.

No MeSH data available.


Related in: MedlinePlus