Indian Journal of Medical Microbiology Home 

CORRESPONDENCE
[Download PDF]
Year : 2013  |  Volume : 31  |  Issue : 2  |  Page : 209--210

Efficacy of disinfectants on clinical isolates of Acinetobacter species

G Prakasam, L Priya, SS Ramesh 
 Department of Microbiology, Dr. ALM Post Graduate Institute of Basic Medical Sciences, University of Madras, Taramani, Chennai, Tamil Nadu, India

Correspondence Address:
S S Ramesh
Department of Microbiology, Dr. ALM Post Graduate Institute of Basic Medical Sciences, University of Madras, Taramani, Chennai, Tamil Nadu
India

How to cite this article:
Prakasam G, Priya L, Ramesh S S. Efficacy of disinfectants on clinical isolates of Acinetobacter species.Indian J Med Microbiol 2013;31:209-210

How to cite this URL:
Prakasam G, Priya L, Ramesh S S. Efficacy of disinfectants on clinical isolates of Acinetobacter species. Indian J Med Microbiol [serial online] 2013 [cited 2020 Apr 2 ];31:209-210
Available from: http://www.ijmm.org/text.asp?2013/31/2/209/115245

Full Text

Dear Editor,

Outbreaks of nosocomial infections have become an important health problem in several countries. This creates a significant burden for both patients and physicians. [1] Different microbial flora survives in the inanimate objects or environments of hospitals and potentially transferred between patients within health-care facilities. [2] Disinfectants have been extensively used in hospital environments and other health-care facilities. [3] Acinetobacter baumannii has the ability to survive for longer duration in hospital environment in spite of disinfection. [4] We have tested a total of 133 clinical isolates of Acinetobacter species, which includes 108 A. baumannii, 13 A. lwoffii, 7 A. junii and 5 A. johnsonii. They were obtained from various clinical specimens such as 46 endotracheal aspirates, 26 blood, 16 pus, 11 urine, 10 broncho alveolar lavage, 10 sputum, 6 wound swabs, 3 oropharyngeal swabs, 3 nasopharyngeal swabs, 1 central vein tip and I diabetic foot ulcer. Minimum inhibitory concentration (MIC) of the following disinfectants such as chloroxylenol, benzalkonium chloride, sodium hypochlorite and phenyl were performed in two fold dilutions by agar dilution method. Time kill assay was also carried out for the isolates at their appropriate break point in different interval time periods such as 0 min, 10 min, 30 min, 60 min and 120 min. [5] The MIC dilutions were ranging from 1:20 to 1:1280. Overnight culture suspensions of Acinetobacter isolates were adjusted to 0.5 McFarland standard for turbidity and 10 μL of suspension was spot inoculated onto plates with above mentioned concentrations of disinfectants. Inoculated plates were incubated at 37°C for 24 h and MIC was determined. The lowest concentration of disinfectants that inhibited the growth of Acinetobacter isolates were considered as MIC. For chloroxylenol, 104/133 (78.1%) isolates were inhibited at a dilution of 1:20, 11/133 (8.2%) were inhibited at 1:160 dilution, 13/133 (9.7%) and 5/133 (3.7%) were inhibited at 1:320 and 1:1280 dilutions respectively. Time kill assay of chloroxylenol showed inhibition at 10 min for 130/133 (97.7%) isolates and 30 min for 3/133 (2.2%) isolates. For benzalkonium chloride, 117/133 (87.9%) isolates were inhibited at a dilution of 1:20, 7/133 (5.2%) were at 1:320, 9/133 (6.7%) were at 1:1280 dilution. In time kill assay for benzalkonium chloride 130/133 (97.7%) and 3/133 (2.2%) isolates were inhibited at a time interval of 10 min and 30 min respectively. For sodium hypochlorite, 14/133 (10.5%) isolates were inhibited at 1:40 dilution, 119/13 3 (89.4%) were at 1:20 dilution. All 133/133 (100%) isolates were inhibited at a time interval of 10 min by time kill assay for sodium hypochlorite. Phenyl compound was ineffective on these isolates as they were not susceptible even in first dilution 1:20. We have observed a varied susceptibility pattern of disinfectants to Acinetobacter species. 97.7% of isolates were inhibited at 10 min exposure time, only 2.2% of isolates were inhibited after 30 min exposure time of chloroxylenol and benzalkonium chloride. Only 10 min was required for sodium hypochlorite to inhibit these isolates. No effect was seen for phenyl compound on these isolates. The appropriate choice of disinfectants and rational practice in disinfection procedures may possibly reduce the burden of Acinetobacter infections among hospitalized individuals by reducing cross transmission.

References

1Falagas ME, Kopterides P, Siempos II. Attributable mortality of Acinetobacter baumannii infection among critically ill patients. Clin Infect Dis 2006;43:389.
2Kramer A, Schwebke I, Kampf G. How long do nosocomial pathogens persist on inanimate surfaces? A systematic review. BMC Infect Dis 2006;6:130.
3Kawamura-Sato K, Wachino J, Kondo T, Ito H, Arakawa Y. Correlation between reduced susceptibility to disinfectants and multidrug resistance among clinical isolates of Acinetobacter species. J Antimicrob Chemother 2010; 65:1975-83.
4Lewis K. Riddle of biofilm resistance. Antimicrob Agents Chemother 2001;45:999-1007.
5Kawamura-Sato K, Wachino J, Kondo T, Ito H, Arakawa Y. Reduction of disinfectant bactericidal activities in clinically isolated Acinetobacter species in the presence of organic material. J Antimicrob Chemother 2008;61:568-76.