Detection of magA Gene in Klebsiella spp. Isolated from Clinical Samples

Document Type : Original Article


1 Department of Immunology, School of Medicine, Hamadan University of Medical Sciences, Hamadan, Iran

2 Department of Medical Microbiology, School of Medicine, Hamadan University of Medical Sciences, Hamadan, Iran


Objective(s): Klebsiella infections are caused mainly by K. pneumoniae and K. oxytoca. In the last two decades, a new type of invasive Klebsiella pneumoniae which contains mucoviscosity-associated gene (magA) has emerged. The aim of this study was to investigate the prevalence of magA gene and to detect antimicrobial susceptibility patterns of Klebsiella
spp. isolated from clinical samples.
Materials and Methods:
Klebsiella isolates were collected from patients admitted to referral hospitals of Hamadan, Iran, during a 12-month period from 2007 to 2008. The samples were analyzed by conventional microbiological methods and polymerase chain reaction (PCR). The hypermucoviscosity (HV) phenotype of Klebsiella
isolates was characterized by formation of viscous strings >5 mm as a positive test. The susceptibility of isolates to routine antibiotics was assessed by agar disk diffusion method.
Out of 105 Klebsiella isolates, 96.2% was identified as K. pneumoniae and 3.8% as K. oxytoca by PCR. magA gene was detected in 4 (3.8%) isolates of K. pneumoniae. The isolates of K. oxytoca contained no magA gene. From 4 isolates with positive magA gene, two of them were HV+ and two were HV- phenotype. Overall, sixty-four isolates (60.95%) of K. pneumoniae
showed an HV positive phenotype and all isolates of K. oxytoca were HV-phenotype. The most effective antibiotics against the isolates were tobramycin (79.05%), ceftazidime (79.05%), ceftizoxime (78.09%), ciprofloxacin (76.19%), ceftriaxone (76.24%) and amikacin (74.29%).
The results suggest that there is also magA associated serotype of the K. pneumoniae in this region. In addition, the presence of HV+ phenotype may not be associated with magA


Podschun R, Ullmann U. Klebsiella spp. as nosocomial patho
gens: epidemiology, taxonomy, typing methods, and pathogenicity factors. Clin Microbiol Rev 1998; 11:589-603.
2. Kang CI, Kim SH, Bang JW, Kim HB, Kim NJ, Kim EC,
et al. Community-acquired versus nosocomial Klebsiella pneumoniae
bacteremia: clinical features, treatment outcomes, and clinical implication of antimicrobial resistance. J Korean Med Sci 2006; 21:816-822.
3. Yu WL, Ko WC, Cheng KC, Lee CC, Lai CC, Chuang YC. Comparison of prevalence of virulence factors for
Klebsiella pneumoniae
liver abscesses between isolates with capsular K1/K2 and non-K1/K2 serotypes. Diagn Microbiol Infect Dis 2008; 62:1-6.
4. Wang JH, Liu YC, Lee SS, Yen MY, Chen YS, Wang JH,
et al. Primary liver abscess due to Klebsiella pneumoniae
in Taiwan. Clin Infect Dis 1998; 26:1434-1438.
5. Liu YC, Cheng DL, Lin CL.
Klebsiella pneumoniae
liver abscess associated with septic endophthalmitis. Arch Int Med 1986; 146:1913- 1916.
6. Chung DR, Lee SS, Lee HR, Kim HB, Choi HJ, Eom JS,
et al. Emerging invasive liver abscess caused by K1 serotype Klebsiella pneumoniae
in Korea. J Infect 2007; 54:578-583.
7. Lederman ER, Crum NF. Pyogenic liver abscess with a focus on
Klebsiella pneumoniae
as a primary pathogen: an emerging disease with unique clinical characteristics. Am J Gastroenterol 2005; 100:322-331.
8. Ohmori S, Shiraki K, Ito K, Inoue H, Ito T, Sakai T,
et al. Septic endophthalmitis and meningitis associated with Klebsiella pneumoniae
liver abscess. Hepatol Res 2002; 22:307-312.
9. Fang CT, Chuang YP, Shun CT, Chang SC, Wang JT. A novel virulence gene in
Klebsiella pneumoniae
strains causing primary liver abscess and septic metastatic complications. J Exp Med 2004; 199:697-705.
10. Lee HC, Chuang YC, Yu WL, Lee NY, Chang CM, Ko NY,
et al. Clinical implications of hypermucoviscosity phenotype in Klebsiella pneumoniae
isolates: association with invasive syndrome in patients with community-acquired bacteraemia. J Int Med 2006; 259:606-614.
11. Blahova J, Kralikova K, Krcmery V, Sr., Babalova M, Menkyna R, Glosova L,
et al.
Four years of monitoring antibiotic resistance in microorganisms from bacteremic patients. J Chemother (Florence, Italy). 2007; 19:665-669.
12. Biedenbach DJ, Moet GJ, Jones RN. Occurrence and antimicrobial resistance pattern comparisons among bloodstream infection isolates from the SENTRY Antimicrobial Surveillance Program (1997-2002). Diagn Microbiol Infect Dis 2004; 50:59-69.
13. Ivanov DV, Egorov AM. [Spreading and mechanisms of antibiotic resistance of microorganisms, producing beta-lactamases. Molecular mechanisms of resistance to beta-lactams of Klebsiella spp. strains, isolated in cases of nosocomial infections]. Biomed khim 2008; 54:104-113.
14. Lagamayo EN. Antimicrobial resistance in major pathogens of hospital-acquired pneumonia in Asian countries. Am J Infect Control 2008; 36:S101-108.
15. Forbes BA, Sahm DF, Weissfeld AS. Bailey & Scott’s Diagnostic Microbiology. UK: Mosby; 2007.
16. Zamani A, Sadeghian S, Ghaderkhani J, Alikhani MY, Najafimosleh M, Goodarzi MT,
et al.
Detection of methicillin-resistance (mec-A) gene in Staphylococcus aureus strains by PCR and determination of antibiotic susceptibility. Ann Microbiol 2007; 57:273-276.
17. Fang FC, Sandler N, Libby SJ. Liver abscess caused by
magA+ Klebsiella pneumoniae
in North America. J Clin Microbiol 2005; 43:991-992.
18. Kurupati P, Chow C, Kumarasinghe G, Poh CL. Rapid detection of
Klebsiella pneumoniae
from blood culture bottles by real-time PCR. J Clin Microbiol 2004; 42:1337-1340.
19. Kovtunovych G, Lytvynenko T, Negrutska V, Lar O, Brisse S, Kozyrovska N. Identification of
Klebsiella oxytoca using a specific PCR assay targeting the polygalacturonase pehX
gene. Res Microbiol 2003; 154:587-592.
20. Mashouf RY, Zamani A, Farahani HS. Diagnostic multiplex polymerase chain reaction assay for the identification of Pseudomonas aeruginosa from the skin biopsy specimens in burn wound infections and detection of antibiotic susceptibility. Saudi Med J 2008; 29:1109-1114.
21. Clinical and Laboratory Standards Institute. Performance standards for antimicrobial susceptibility testing, 17th informational supplement. M100-S17. Clinical and Laboratory Standards Institute, Wayne: PA;2007.
22. Struve C, Krogfelt KA. Role of capsule in
Klebsiella pneumoniae virulence: lack of correlation between in vitro and in vivo
studies. FEMS Microbiol lett 2003; 218:149-154.
23. Yeh KM, Kurup A, Siu LK, Koh YL, Fung CP, Lin JC,
et al. Capsular serotype K1 or K2, rather than magA and rmpA, is a major virulence determinant for Klebsiella pneumoniae
liver abscess in Singapore and Taiwan. J Clin Microbiol 2007; 45:466-471.
24. Fung CP, Chang FY, Lee SC, Hu BS, Kuo BI, Liu CY,
et al. A global emerging disease of Klebsiella pneumoniae
liver abscess: is serotype K1 an important factor for complicated endophthalmitis? Gut 2002; 50:420-424.
25. Struve C, Bojer M, Nielsen EM, Hansen DS, Krogfelt KA. Investigation of the putative virulence gene
magA in a worldwide collection of 495 Klebsiella isolates: magA is restricted to the gene cluster of Klebsiella pneumoniae
capsule serotype K1. J Med Microbiol 2005; 54:1111-1113.
26. Kuo LC, Yu CJ, Kuo ML, Chen WN, Chang CK, Lin HI,
et al.
Antimicrobial resistance of bacterial isolates from respiratory care wards in Taiwan: a horizontal surveillance study. Int J Antimicrobial Agents 2008; 31:420-426.