Abstract:
Resistance to colistin, mediated by chromosomal mutations and more recently, by
plasmid-borne
mcr genes, is increasingly being reported in bacterial isolates taken
from humans, animals, farms, foods, and the environment. To easily identify and contain
this quickly spreading menace, efficient diagnostics that are cheaper, faster, simpler,
sensitive, and specific have become indispensable and urgently necessary. A
thorough and systematic review of the literature available at Pubmed, ScienceDirect
and Web of Science was thus undertaken to identify articles describing novel and
efficient colistin resistance-and
mcr gene-detecting
methods. From the final 23
studies included in this review, both phenotypic and molecular tests were found. The
phenotypic tests consisted of novel culture media viz., SuperPolymyxin™, CHROMagar
COL-APSE
and LBJMR media, commercial automated MIC-determining
instruments
such as MICRONAUT-S,
Vitek 2, BD Phoenix, Sensititre and MicroScan, and novel
assays such as Colistin MAC test, Colispot, rapid polymxin NP test (RPNP), alteration
of Zeta potential, modified RPNP test, MICRONAUT-MIC
Strip, MIC Test Strip, UMIC
System, and Sensitest™ Colistin. Molecular diagnostics consisted of the CT103XL
microarray, eazyplex® SuperBug kit, and Taqman®/SYBR Green® real-time
PCR assays,
with 100% sensitivity and specificity plus a shorter turnaround time (<3 hr).
Based on the sensitivity, specificity, cost, required skill and turnaround time, the
RPNP test and/or novel culture media is recommended for under-resourced
laboratories
while the Multiplex PCR or Taqman®/SYBR Green® real-time
PCR assay alongside
the RPNP or novel culture media is suggested for well-resourced
ones.
