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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

(A) Percentage of survivals of Group I injected with isolate IMP33, harboring blaCTX-M-15 gene, during the monitoring period (p-value = 0.049). The concentration of the bacteria injected (3xLD50) = 1.68 × 106 CFU/μl. Concentration of the antimicrobial agents added: COL: 6.744 μg/μl, ETP: 6.744 μg/μl, IMP: 6.744 μg/μl, MER: 0.4215 μg/μl, RIF: 107.904 μg/μl, FOS: 13811.712 μg/μl, KAN: 215.808 μg/μl, TIG: 26.976 μg/μl. (B) Percentage of survivals of Group II injected with isolate IMP53, harboring both blaCTX-M-15 and blaOXA-48 genes, during the monitoring period (p-value = 0.031). The concentration of the bacteria injected (3x LD50) = 3 × 107 CFU/μl. Concentration of the antimicrobial agents added: COL: 120, ETP: 1920 μg/μl, IMP: 480 μg/μl, MER: 240 μg/μl, RIF: 480 μg/μl, FOS: 30720 μg/μl, KAN: 7680 μg/μl, TIG: 30 μg/μl. (C) Percentage of survivals of Group III injected with isolate IMP216, harboring blaNDM-1 gene, during the monitoring period (p-value = 0.029). The concentration of the bacteria injected (3x LD50) = 6.48 × 106 CFU/μl. Concentration of the antimicrobial agents added: COL: 11289.6 μg/μl, ETP: 45158.4 μg/μl, IMP: 90316.8 μg/μl, MER: 5644.8 μg/μl, RIF: 11289.6 μg/μl, FOS: 90316.8 μg/μl, KAN: 1445069 μg/μl, TIG: 352.8 μg/μl. (D) Percentage of survivals of Group IV injected with isolate KPC, harboring the blaKPC-2 gene, during the monitoring period (p-value = 0.043). The concentration of the bacteria injected (3x LD50) = 3 × 108 CFU/μl. Concentration of the antimicrobial agents added: COL: 1200 μg/μl, ETP: 2400 μg/μl, IMP: 2400 μg/μl, MER: 2400 μg/μl, RIF: 4800 μg/μl, FOS: 4800 μg/μl, KAN: 19200 μg/μl, TIG: 300 μg/μl. TSB, Tryptic Soy Broth; COL, colistin; CAZ, ceftazidime; ETP, ertapenem; IMP, imipenem; MER, meropenem; KAN, kanamycin; FOS, fosfomycin; and TIG, tigecycline.
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Figure 3: (A) Percentage of survivals of Group I injected with isolate IMP33, harboring blaCTX-M-15 gene, during the monitoring period (p-value = 0.049). The concentration of the bacteria injected (3xLD50) = 1.68 × 106 CFU/μl. Concentration of the antimicrobial agents added: COL: 6.744 μg/μl, ETP: 6.744 μg/μl, IMP: 6.744 μg/μl, MER: 0.4215 μg/μl, RIF: 107.904 μg/μl, FOS: 13811.712 μg/μl, KAN: 215.808 μg/μl, TIG: 26.976 μg/μl. (B) Percentage of survivals of Group II injected with isolate IMP53, harboring both blaCTX-M-15 and blaOXA-48 genes, during the monitoring period (p-value = 0.031). The concentration of the bacteria injected (3x LD50) = 3 × 107 CFU/μl. Concentration of the antimicrobial agents added: COL: 120, ETP: 1920 μg/μl, IMP: 480 μg/μl, MER: 240 μg/μl, RIF: 480 μg/μl, FOS: 30720 μg/μl, KAN: 7680 μg/μl, TIG: 30 μg/μl. (C) Percentage of survivals of Group III injected with isolate IMP216, harboring blaNDM-1 gene, during the monitoring period (p-value = 0.029). The concentration of the bacteria injected (3x LD50) = 6.48 × 106 CFU/μl. Concentration of the antimicrobial agents added: COL: 11289.6 μg/μl, ETP: 45158.4 μg/μl, IMP: 90316.8 μg/μl, MER: 5644.8 μg/μl, RIF: 11289.6 μg/μl, FOS: 90316.8 μg/μl, KAN: 1445069 μg/μl, TIG: 352.8 μg/μl. (D) Percentage of survivals of Group IV injected with isolate KPC, harboring the blaKPC-2 gene, during the monitoring period (p-value = 0.043). The concentration of the bacteria injected (3x LD50) = 3 × 108 CFU/μl. Concentration of the antimicrobial agents added: COL: 1200 μg/μl, ETP: 2400 μg/μl, IMP: 2400 μg/μl, MER: 2400 μg/μl, RIF: 4800 μg/μl, FOS: 4800 μg/μl, KAN: 19200 μg/μl, TIG: 300 μg/μl. TSB, Tryptic Soy Broth; COL, colistin; CAZ, ceftazidime; ETP, ertapenem; IMP, imipenem; MER, meropenem; KAN, kanamycin; FOS, fosfomycin; and TIG, tigecycline.

Mentions: As for the sub-groups (3–12) in both Groups I and III, injected with isolates IMP33 (blaCTX-M-15) and IMP216 (blaNDM-1) respectively, which received an injection of antimicrobial agents singly or in combination, a 100% survival rate was observed. On the other hand, the sub-groups (3–12) in Group II, injected with isolate IMP53 (blaCTXM-15 and blaOXA-48) was 80%. While the lowest survival rate of 66% was observed in sub-groups (3–12), in Group IV, injected with isolate KPC (blaKPC-2). The survival rates according to the treatments for each of the four isolates are shown in Figures 3A–D.


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)

(A) Percentage of survivals of Group I injected with isolate IMP33, harboring blaCTX-M-15 gene, during the monitoring period (p-value = 0.049). The concentration of the bacteria injected (3xLD50) = 1.68 × 106 CFU/μl. Concentration of the antimicrobial agents added: COL: 6.744 μg/μl, ETP: 6.744 μg/μl, IMP: 6.744 μg/μl, MER: 0.4215 μg/μl, RIF: 107.904 μg/μl, FOS: 13811.712 μg/μl, KAN: 215.808 μg/μl, TIG: 26.976 μg/μl. (B) Percentage of survivals of Group II injected with isolate IMP53, harboring both blaCTX-M-15 and blaOXA-48 genes, during the monitoring period (p-value = 0.031). The concentration of the bacteria injected (3x LD50) = 3 × 107 CFU/μl. Concentration of the antimicrobial agents added: COL: 120, ETP: 1920 μg/μl, IMP: 480 μg/μl, MER: 240 μg/μl, RIF: 480 μg/μl, FOS: 30720 μg/μl, KAN: 7680 μg/μl, TIG: 30 μg/μl. (C) Percentage of survivals of Group III injected with isolate IMP216, harboring blaNDM-1 gene, during the monitoring period (p-value = 0.029). The concentration of the bacteria injected (3x LD50) = 6.48 × 106 CFU/μl. Concentration of the antimicrobial agents added: COL: 11289.6 μg/μl, ETP: 45158.4 μg/μl, IMP: 90316.8 μg/μl, MER: 5644.8 μg/μl, RIF: 11289.6 μg/μl, FOS: 90316.8 μg/μl, KAN: 1445069 μg/μl, TIG: 352.8 μg/μl. (D) Percentage of survivals of Group IV injected with isolate KPC, harboring the blaKPC-2 gene, during the monitoring period (p-value = 0.043). The concentration of the bacteria injected (3x LD50) = 3 × 108 CFU/μl. Concentration of the antimicrobial agents added: COL: 1200 μg/μl, ETP: 2400 μg/μl, IMP: 2400 μg/μl, MER: 2400 μg/μl, RIF: 4800 μg/μl, FOS: 4800 μg/μl, KAN: 19200 μg/μl, TIG: 300 μg/μl. TSB, Tryptic Soy Broth; COL, colistin; CAZ, ceftazidime; ETP, ertapenem; IMP, imipenem; MER, meropenem; KAN, kanamycin; FOS, fosfomycin; and TIG, tigecycline.
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Figure 3: (A) Percentage of survivals of Group I injected with isolate IMP33, harboring blaCTX-M-15 gene, during the monitoring period (p-value = 0.049). The concentration of the bacteria injected (3xLD50) = 1.68 × 106 CFU/μl. Concentration of the antimicrobial agents added: COL: 6.744 μg/μl, ETP: 6.744 μg/μl, IMP: 6.744 μg/μl, MER: 0.4215 μg/μl, RIF: 107.904 μg/μl, FOS: 13811.712 μg/μl, KAN: 215.808 μg/μl, TIG: 26.976 μg/μl. (B) Percentage of survivals of Group II injected with isolate IMP53, harboring both blaCTX-M-15 and blaOXA-48 genes, during the monitoring period (p-value = 0.031). The concentration of the bacteria injected (3x LD50) = 3 × 107 CFU/μl. Concentration of the antimicrobial agents added: COL: 120, ETP: 1920 μg/μl, IMP: 480 μg/μl, MER: 240 μg/μl, RIF: 480 μg/μl, FOS: 30720 μg/μl, KAN: 7680 μg/μl, TIG: 30 μg/μl. (C) Percentage of survivals of Group III injected with isolate IMP216, harboring blaNDM-1 gene, during the monitoring period (p-value = 0.029). The concentration of the bacteria injected (3x LD50) = 6.48 × 106 CFU/μl. Concentration of the antimicrobial agents added: COL: 11289.6 μg/μl, ETP: 45158.4 μg/μl, IMP: 90316.8 μg/μl, MER: 5644.8 μg/μl, RIF: 11289.6 μg/μl, FOS: 90316.8 μg/μl, KAN: 1445069 μg/μl, TIG: 352.8 μg/μl. (D) Percentage of survivals of Group IV injected with isolate KPC, harboring the blaKPC-2 gene, during the monitoring period (p-value = 0.043). The concentration of the bacteria injected (3x LD50) = 3 × 108 CFU/μl. Concentration of the antimicrobial agents added: COL: 1200 μg/μl, ETP: 2400 μg/μl, IMP: 2400 μg/μl, MER: 2400 μg/μl, RIF: 4800 μg/μl, FOS: 4800 μg/μl, KAN: 19200 μg/μl, TIG: 300 μg/μl. TSB, Tryptic Soy Broth; COL, colistin; CAZ, ceftazidime; ETP, ertapenem; IMP, imipenem; MER, meropenem; KAN, kanamycin; FOS, fosfomycin; and TIG, tigecycline.
Mentions: As for the sub-groups (3–12) in both Groups I and III, injected with isolates IMP33 (blaCTX-M-15) and IMP216 (blaNDM-1) respectively, which received an injection of antimicrobial agents singly or in combination, a 100% survival rate was observed. On the other hand, the sub-groups (3–12) in Group II, injected with isolate IMP53 (blaCTXM-15 and blaOXA-48) was 80%. While the lowest survival rate of 66% was observed in sub-groups (3–12), in Group IV, injected with isolate KPC (blaKPC-2). The survival rates according to the treatments for each of the four isolates are shown in Figures 3A–D.

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