Investigation of Colistin Heteroresistance Among Acinetobacter baumannii Isolates

Abstract

Colistin heteroresistance is a step for the development of full colistin resistance. Recently, heteroresistance and resistance to colistin have been reported for carbapenem-resistant Acinetobacter baumannii (CRAB) isolates in different countries. In this study, we aimed to investigate colistin heteroresistance profiles of CRAB strains isolated from various units of a secondary care hospital in our city. Forty-seven colistin susceptible CRAB isolates stored in our University Hospital Medical Microbiology Department collection and previously collected from secondary care hospital between June 2016 and June 2017 were included in the study. Identification and antibiograms of the isolates were performed by the automated system (Phoenix, Becton-Dickinson, USA). Colistin MICs were confirmed by broth microdilution test for the stored bacteria. Mueller-Hinton agar (MHA) plates containing colistin at concentration of 4 µg/ml were prepared for detection of heteroresistant subpopulations. The plates were inoculated with 100 microliters amount from CRAB bacterial suspensions (108 CFU/ml). Colonies which were able to grow on MHA plates after 48 hours incubation were defined as heteroresistant and counted manually. All isolates were susceptible to colistin and resistant to carbapenems. Among 47 CRAB isolates, 16 isolates (34 %) were found heteroresistant to colistin. The rates of heteroresistance for these isolates were between 10-7 and 10-4. In our study, we detected a significant rate of heteroresistance (34 %) to colistin. In our country, there are limited numbers of studies about heteroresistance to colistin. This study may be one of the first researches reporting the existence of colistin heteroresistance among CRAB isolates in our country. New and larger studies are necessary to evaluate the real rate and clinical importance of colistin heteroresistance.

Keywords

• A.baumannii
• carbapenem
• colistin
• heteroresistance

Acinetobacter baumannii İzolatlarında Kolistin Heterodirencinin Araştırılması

Abstract

Heterodirenç, kolistin direncinin gelişimi için bir adım kabul edilmektedir. Son yıllarda, farklı ülkelerden karbapenem dirençli A.baumannii (KDAB) izolatlarında kolistine karşı heterodirenç ve direnç gelişimi bildirilmiştir. Bu çalışmada, ilimizde ikinci basamak bir hastanenin çeşitli birimlerinden izole edilen KDAB izolatlarının kolistine karşı heterodirenç profillerinin araştırılması amaçlanmıştır. Haziran 2016 ve Haziran 2017 tarihleri arasında ikinci basamak hastaneden toplanan ve Üniversite Hastanemizin Tıbbi Mikrobiyoloji Anabilim Dalı arşivinde saklanan, kolistine duyarlı 47 KDAB izolatı çalışmaya dahil edilmiştir. İzolatların tanımlanması ve antibiyogramları otomatize sistem (Phoenix, BectonDickinson, ABD) ile yapılmıştır. Stoklanan bakterilerin kolistin minimum inhibisyon konsantrasyonları sıvı mikrodilüsyon yöntemi ile doğrulanmıştır. Heterodirençli alt popülasyonların tespiti için 4 µg/ml kolistin içeren Mueller-Hinton agar (MHA) petri plakları hazırlanmıştır. Plaklara, 100 mikrolitre KDAB bakteri süspansiyonu (108 CFU/ml) ilave edilmiştir. 24 saat inkübasyonun ardından MHA ’da üreme gösteren koloniler, heterodirençli olarak tanımlanmış ve manüel olarak koloni sayımı yapılmıştır. Toplanan tüm izolatlar kolistine karşı duyarlı ve karbapenemlere karşı dirençli bulunmuştur. İzolatların % 34’ünde (16/47 izolat) kolistine karşı heterodirenç tespit edilmiştir. Bu suşlarda heterodirenç oranları 10-7 ile 10-4 arasında gözlemlenmiştir. Çalışmamızda izolatlarda önemli oranda (% 34) heterodirenç saptanmıştır. Ülkemizde, kolistin heterodirenci ile ilgili çalışmalar sınırlı sayıdadır. Bu çalışmamız ülkemizde KDAB izolatlarında kolistin heterodirencinin raporlandığı ilk araştırmalardan biridir. Bununla beraber, kolistin heterodirencinin gerçek oranını ve klinik önemini ortaya koymak için yeni ve daha geniş çalışmalar gereklidir.

Keywords

• A.baumannii
• heterodirenç
• karbapenem
• kolistin

References

1. Ahmed SS, Alp E, Hopman J, Voss A. Global Epidemiology on Colistin Resistant Acinetobacter baumannii. J Infect Dis Ther. 2016;4(4):287. https://doi.org/10.4172/2332-0877.1000287
2. Al-Sweih NA, Al-Hubail MA, Rotimi VO. Emergence of tigecycline and colistin resistance in Acinetobacter species isolated from patients in Kuwait hospitals. J Chemother. 2011;23(1):13-6. https://doi.org/10.1179/joc.2011.23.1.13
3. Beceiro A, Llobet E, Aranda J, et al. Phosphoethanolamine modification of lipid A in colistin-resistant variants of Acinetobacter baumannii mediated by the pmrAB two component regulatory system. Antimicrob Agents Chemother. 2011;55(7): 3370-9. https://doi.org/10.1128/AAC.00079-11
4. Cikman A, Gulhan B, Aydin M, et al. In vitro activity of colistin in combination with tigecycline against carbapenem-resistant Acinetobacter baumannii strains isolated from patients with ventilatorassociated pneumonia. Int J Med Sci. 2015;12(9):695-700. https://doi.org/10.7150/ijms.11988
5. Çağlan E, Nigiz Ş, Sancak B, Gür D. Resistance and heteroresistance to colistin among clinical isolates of Acinetobacter baumannii. Acta Microbiol Immunol Hung. 2019;9:1-5. https://doi.org/10.1556/030.66.2019.021
6. CLSI Performance Standards for Antimicrobial Susceptibility Testing, CLSI supplement M100. 27th ed. Philadelphia: Clinical and Laboratory Standards Institute; (2017).
7. Drlica K, Shopsin B, Zhao X. Heteroresistance: A Harbinger of Future Resistance, “Fong I.W, Shlaes D, Drlica K (eds): Antimicrobial Resistance in the 21st Century” kitabında s.269-296, Springer, Cham (2018). https://doi.org/10.1007/978-3-319-78538-7_9
8. Eser Ö, Ergin A, Hasçelik G. Acinetobacter türlerinde antimikrobiyal direnç ve metallo-beta-laktamaz varlığı. Mikrobiyoloji Bul. 2009;43(43):383-90.

9. Gazel D, Tatman-Otkun M. Investigation of colistin heteroresistance and some factors affecting heteroresistance in carbapenem-resistant A. baumannii strains. Mediterr J Infect Microb Antimicrob. 2017;6:1. https://doi.org/10.4274/mjima.2017.1
10. Hawley JS, Murray CK, Jorgensen JH. Colistin heteroresistance in Acinetobacter and its association with previous colistin therapy. Antimicrob Agents Chemother. 2008;52(1):351-2. https://doi.org/10.1128/AAC.00766-07
11. Herrera ME, Mobilia LN, Posse GR .Comparative evaluation of the sensitivity of Acinetobacter to colistin, using the prediffusion and minimum inhibitory concentration methods: detection of heteroresistant isolates. Rev Argent Microbiol. 2011;43(2):115-9.
12. Karabay O. Klinik örneklerden izole edilen Acinetobacter baumannii suşlarında antibiyotik direnç durumlarının belirlenmesi ve karbapenemaz direnç genlerinin araştırılması. Yüksek Lisans [tez]. Gaziantep: Gaziantep Üniversitesi; (2019).
13. Kim Y, Bae IK, Jeong SH, Yong D, Lee K. In vivo selection of pan-drug resistant Acinetobacter baumannii during antibiotic treatment. Yonsei Med J. 2015;56(4):928-34. https://doi.org/10.3349/ymj.2015.56.4.928
14. Li J, Rayner CR, Nation RL, et al. Pharmacokinetics of colistin methanesulfonate and colistin in a critically ill patient receiving continuous venovenous hemodiafiltration. Antimicrob Agents Chemother. 2005;49(11):4814-5. https://doi.org/10.1128/AAC.49.11.4814-4815.2005
15. Li J, Rayner CR, Rayner CR, et al. Heteroresistance to colistin in multidrug-resistant Acinetobacter baumannii. Antimicrob Agents Chemother. 2006;50(9):2946-50. https://doi.org/10.1128/AAC.00103-06
16. Liu YY, Wang Y, Walsh TR, et al. Emergence of plasmid-mediated colistin resistance mechanism MCR-1 in animals and human beings in China: a microbiological and molecular biological study. Lancet Infect Dis. 2016;16(2):161-8. https://doi.org/10.1016/S1473-3099(15)00424-7
17. Moffatt JH, Harper M, Harrison P, et al. Colistin resistance in Acinetobacter baumannii is mediated by complete loss of lipopolysaccharide production. Antimicrob Agents Chemother. 2010;54(12):4971-7. https://doi.org/10.1128/AAC.00834-10
18. Moosavian M, Shoja S, Nashibi R, et al. Post neurosurgical meningitis due to colistin heteroresistant Acinetobacter baumannii. Jundishapur J Microbiol. 2014;7(10):e12287. https://doi.org/10.5812/jjm.12287
19. Murray PR, Rosenthal KS, Pfaller MA. Pseudomonas and related bacteria, “Murray PR (ed). Medical microbiology, 8. baskı” kitabında s.278-9, Elsevier Inc, Philadelphia (2016).
20. Oikonomou O, Sarrou S, Papagiannitsis CC, et al. Rapid dissemination of colistin and carbapenem resistant Acinetobacter baumannii in Central Greece: mechanisms of resistance, molecular identification and epidemiological data. BMC Infect Dis. 2015;15:559. https://doi.org/10.1186/s12879-015-1297-x
21. Pournaras S, Ikonomidis A, Markogiannakis A, Maniatis AN, Tsakris A. Heteroresistance to carbapenems in Acinetobacter baumannii. J. Antimicrob. Chemother. 2005;55(6):1055-6. https://doi.org/10.1093/jac/dki115
22. Rodriguez CH, Barberis C, Nastro M, et al. Impact of heteroresistance to colistin in meningitis caused by Acinetobacter baumannii. J Infect. 2012;64(1):119-21. https://doi.org/10.1016/j.jinf.2011.10.007
23. Rodriguez CH, De Ambrosio A, Bajuk M, et al. In vitro antimicrobials activity against endemic Acinetobacter baumannii multiresistant clones. J Infect Dev Ctries. 2010;4(3):164-7. https://doi.org/10.3855/jidc.604
24. Rolain JM, Roch A, Castanier M, Papazian L, Raoult D. Acinetobacter baumannii resistant to colistin with impaired virulance: a case report from France. J Infect Dis. 2011;204(7):1146-7. https://doi.org/10.1093/infdis/jir475
25. Sievert DM, Ricks P, Edwards JR, et al. Antimicrobialresistant pathogens associated with healthcareassociated infections: summary of data reported to the National Healthcare Safety Network at the Centers for Disease Control and Prevention, 2009-2010. Infect Control Hosp Epidemiol. 2013;34(1):1-14. https://doi.org/10.1086/668770
26. Souli M, Kontopidou FV, Koratzanis E, et al. In vitro activity of tigecycline against multiple-drug-resistant, including pan-resistant, gram-negative and grampositive clinical isolates from Greek hospitals. Antimicrob Agents Chemother. 2006;50(9):3166-9. https://doi.org/10.1128/AAC.00322-06
27. Srinivas P, Hunt LN, Pouch SM, et al. Detection of colistin heteroresistance in Acinetobacter baumannii from blood and respiratory isolates. Diagn Microbiol Infect Dis. 2018;91(2):194-8. https://doi.org/10.1016/j.diagmicrobio.2018.01.028
28. Tan CH, Li J, Nation RL. Activity of colistin against heteroresistant Acinetobacter baumannii and emergence of resistance in an in vitro pharmacokinetic/pharmocodynamic model. Antimicrob Agents Chemother. 2007;51(9):3413-5. https://doi.org/10.1128/AAC.01571-06
29. Yau W, Owen RJ, Poudyal A, et al. Colistin heteroresistance in multidrug-resistant Acinetobacter baumannii clinical isolates from the Western Pacific region in the SENTRY antimicrobial surveillance programme. J Infect. 2009;58(2):138-44. https://doi.org/10.1016/j.jinf.2008.11.002