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Analysis of β-lactamase phenotypes and carriage of selected β-lactamase genes among Escherichia coli strains obtained from Kenyan patients during an 18-year period

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Abstract
Background: Although beta-lactam antibiotics are heavily used in many developing countries, the diversity of beta-lactamase genes (bla) is poorly understood. We screened for major beta-lactamase phenotypes and diversity of bla genes among 912 E. coli strains isolated from clinical samples obtained between 1992 and 2010 from hospitalized and non-hospitalized patients. Results: None of the isolates was resistant to carbapenems but 30% of all isolates were susceptible to cefepime, cephamycins and piperacillin-tazobactam. Narrow spectrum beta-lactamase (NSBL) phenotype was observed in 278 (30%) isolates that contained bla(TEM-1) (54%) or bla(SHV-1) (35%) or both (11%). Extended Spectrum beta-lactamase (ESBL) phenotype was detected in 247 (27%) isolates which carried bla(CTX-M-14) (29%), bla(CTX-M-15) (24%), bla(CTX-M-9) (2%), bla(CTX-M-8) (4%), bla(CTX-M-3) (11%), bla(CTX-M-1) (6%), bla(SHV-5) (3%), bla(SHV-12) (5%), and bla(TEM-52) (16%). Complex Mutant TEM-like (CMT) phenotype was detected in 220 (24%) isolates which carried bla(TEM-125) (29%), while bla(TEM-50), bla(TEM-78), bla(TEM-109), bla(TEM -152) and bla(TEM-158) were detected in lower frequencies of between 7% and 11%. Majority of isolates producing a combination of CTX-M-15+OXA-1+TEM-1 exhibited resistance phenotypes barely indistinguishable from those of CMT-producers. Although 73 (8%) isolates exhibited Inhibitor Resistant TEM-like (IRT) phenotype, bla(TEM-103) was the only true IRT-encoding gene identified in 18 (25%) of strains with this phenotype while the rest produced a combination of TEM-1 + OXA-1. The pAmpCs-like phenotype was observed in 94 (10%) isolates of which 77 (82%) carried bla(CMY-2) while 18% contained bla(CMY-1). Isolates from urine accounted for 53%, 53%, 74% and 72% of strains exhibiting complex phenotypes such as IRT, ESBL, CMT or pAmpC respectively. On the contrary, 55% isolates from stool exhibited the relatively more susceptible NSBL-like phenotype. All the phenotypes, and majority of the bla genes, were detected both in isolates from hospitalized and non-hospitalized patients but complex phenotypes were particularly common among strains obtained between 2000 and 2010 from urine of hospitalized patients. Conclusions: The phenotypes and diversity of bla genes in E. coli strains implicated in clinical infections in non-hospitalized and hospitalized patients in Kenya is worryingly high. In order to preserve the efficacy of beta-lactam antibiotics, culture and susceptibility data should guide therapy and surveillance studies for beta-lactamase-producers in developing countries should be launched.
Keywords
KLEBSIELLA-PNEUMONIAE, CTX-M, EXTENDED-SPECTRUM, MOLECULAR CHARACTERIZATION, BLA(CTX-M) GENES, BLA(TEM) GENES, RESISTANCE, SALMONELLA, ENTEROBACTERIACEAE, PLASMID

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Chicago
Kiiru, John, Samuel Kariuki, Bruno Goddeeris, and Patrick Butaye. 2012. “Analysis of Β-lactamase Phenotypes and Carriage of Selected Β-lactamase Genes Among Escherichia Coli Strains Obtained from Kenyan Patients During an 18-year Period.” Bmc Microbiology 12.
APA
Kiiru, J., Kariuki, S., Goddeeris, B., & Butaye, P. (2012). Analysis of β-lactamase phenotypes and carriage of selected β-lactamase genes among Escherichia coli strains obtained from Kenyan patients during an 18-year period. BMC MICROBIOLOGY, 12.
Vancouver
1.
Kiiru J, Kariuki S, Goddeeris B, Butaye P. Analysis of β-lactamase phenotypes and carriage of selected β-lactamase genes among Escherichia coli strains obtained from Kenyan patients during an 18-year period. BMC MICROBIOLOGY. 2012;12.
MLA
Kiiru, John, Samuel Kariuki, Bruno Goddeeris, et al. “Analysis of Β-lactamase Phenotypes and Carriage of Selected Β-lactamase Genes Among Escherichia Coli Strains Obtained from Kenyan Patients During an 18-year Period.” BMC MICROBIOLOGY 12 (2012): n. pag. Print.
@article{3116935,
  abstract     = {Background: Although beta-lactam antibiotics are heavily used in many developing countries, the diversity of beta-lactamase genes (bla) is poorly understood. We screened for major beta-lactamase phenotypes and diversity of bla genes among 912 E. coli strains isolated from clinical samples obtained between 1992 and 2010 from hospitalized and non-hospitalized patients.
Results: None of the isolates was resistant to carbapenems but 30\% of all isolates were susceptible to cefepime, cephamycins and piperacillin-tazobactam. Narrow spectrum beta-lactamase (NSBL) phenotype was observed in 278 (30\%) isolates that contained bla(TEM-1) (54\%) or bla(SHV-1) (35\%) or both (11\%). Extended Spectrum beta-lactamase (ESBL) phenotype was detected in 247 (27\%) isolates which carried bla(CTX-M-14) (29\%), bla(CTX-M-15) (24\%), bla(CTX-M-9) (2\%), bla(CTX-M-8) (4\%), bla(CTX-M-3) (11\%), bla(CTX-M-1) (6\%), bla(SHV-5) (3\%), bla(SHV-12) (5\%), and bla(TEM-52) (16\%). Complex Mutant TEM-like (CMT) phenotype was detected in 220 (24\%) isolates which carried bla(TEM-125) (29\%), while bla(TEM-50), bla(TEM-78), bla(TEM-109), bla(TEM -152) and bla(TEM-158) were detected in lower frequencies of between 7\% and 11\%. Majority of isolates producing a combination of CTX-M-15+OXA-1+TEM-1 exhibited resistance phenotypes barely indistinguishable from those of CMT-producers. Although 73 (8\%) isolates exhibited Inhibitor Resistant TEM-like (IRT) phenotype, bla(TEM-103) was the only true IRT-encoding gene identified in 18 (25\%) of strains with this phenotype while the rest produced a combination of TEM-1 + OXA-1. The pAmpCs-like phenotype was observed in 94 (10\%) isolates of which 77 (82\%) carried bla(CMY-2) while 18\% contained bla(CMY-1).
Isolates from urine accounted for 53\%, 53\%, 74\% and 72\% of strains exhibiting complex phenotypes such as IRT, ESBL, CMT or pAmpC respectively. On the contrary, 55\% isolates from stool exhibited the relatively more susceptible NSBL-like phenotype. All the phenotypes, and majority of the bla genes, were detected both in isolates from hospitalized and non-hospitalized patients but complex phenotypes were particularly common among strains obtained between 2000 and 2010 from urine of hospitalized patients.
Conclusions: The phenotypes and diversity of bla genes in E. coli strains implicated in clinical infections in non-hospitalized and hospitalized patients in Kenya is worryingly high. In order to preserve the efficacy of beta-lactam antibiotics, culture and susceptibility data should guide therapy and surveillance studies for beta-lactamase-producers in developing countries should be launched.},
  articleno    = {155},
  author       = {Kiiru, John and Kariuki, Samuel and Goddeeris, Bruno and Butaye, Patrick},
  issn         = {1471-2180},
  journal      = {BMC MICROBIOLOGY},
  language     = {eng},
  pages        = {11},
  title        = {Analysis of \ensuremath{\beta}-lactamase phenotypes and carriage of selected \ensuremath{\beta}-lactamase genes among Escherichia coli strains obtained from Kenyan patients during an 18-year period},
  url          = {http://dx.doi.org/10.1186/1471-2180-12-155},
  volume       = {12},
  year         = {2012},
}

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