Among 152, 103 (68%) isolates were resistant to Meropenem and 95 (63%) isolates were resistant to
imipenem. It was observed that Klebsiella pneumoniae 39 (26%), Pseudomonas aeruginosa 29 (19%) and Escherichia coli 21 (14%) were predominant carbapenem-resistant isolates followed by Serratia marcescens 3 (3%), Klebsiella oxytoca 2 (1%) and Enterobacter agglomerans 2 (1%) as shown in Figure 2.
Also, the minimum inhibitory concentration (MIC) value of
imipenem for clinical isolates of K.
All carbapenemase positive strains, including MBL and CHDL were found to be resistant or intermediately susceptible to carbapenems with MICs of
imipenem and meropenem ranging from 8 to >128 mg/L.
coli isolates showed more sensitivity to Amikacin 57(76%) followed by
Imipenem 57(66.67%), Ofloxacin 48(64%), Ciprofloxacin 44(58.67%), Norfloxacin 42(56%) and 75(100%) were resistant to Penicillin, Ceftriaxone, Ceftazidime and Cefotaxime (Table-2 and Figure-2).
Staphylococcus aureus isolates showed least resistance to
imipenem (2.6%) followed by linezolid.
Antibiotic susceptibility testing was determined for this isolates to routinely used antibiotics such as to piperacillintazobactam, cefotaxime, ceftazidime, tetracycline, cotrimoxazole, aztreonam, gentamicin, and
imipenem by Kirby Bauer disc diffusion method as per CLSI guideline.
Resistance by disk diffusion technique noted in Salmonella Paratyphi A was ampicillin 60%, chloramphenicol 40%, cotrimoxazole 38%, ceftriaxone 7.9%, ciprofloxacin 8%, cefpodoxime 7.9%,
imipenem and ertapenem 2.6%, aztreonam 1.3%, moxifloxacin 6.6%, and gatifloxacin 1.3%.
This situation is alarming as not only the prevalence of the non-fermenter, Acinetobacter species increasing so is the
imipenem resistance which has increased from 60.6% to 74% within two years.
Few Genetic Mutations Observed in Two Clonally Related Carbapenem-Heteroresistant Strains after Lethal
Imipenem Exposure.