Prevalence of CTX-M Extended Spectrum β-lactamase-producing Enterobacteriaceae at a Private Tertiary Hospital in Southern Philippines


Mary Ann H. Lucena1,2, Ephrime B. Metillo2, and Jose M. Oclarit3

1Laboratory Department, Mindanao Sanitarium and Hospital, Iligan City, Philippines
2Department of Biological Sciences, Mindanao State University-
Iligan Institute of Technology, Iligan City, Philippines
3Center for Biomolecular Sciences, Laboratory of Applied Biochemistry &
Molecular Biology, Mountain View College, Valencia City, Philippines

corresponding author: This email address is being protected from spambots. You need JavaScript enabled to view it.



The emergence of extended spectrum β-lactamase (ESBL)-producing Enterobacteriaceae is one of the growing healthcare concerns worldwide. ESBLs are plasmid encoded enzymes that confer resistance to broad-spectrum cephalosporins and monobactams. Plasmids that carry genes that code for ESBLs often carry other resistance determinants and because of these, infections caused by ESBL-producing Enterobacteriaceae are difficult to treat contributing to the problem of nosocomial infection. To evaluate the prevalence of ESBL-producing Enterobacteriaceae at Mindanao Sanitarium and Hospital in southern Philippines, Escherichia coli, Klebsiella species, and Enterobacter species isolated from clinical samples, were screened and confirmed for the presence of ESBLs. Specific primers for CTX-M, TEM and SHV ESBL enzymes were used. From a total of 583 isolates collected from September 2005 to September 2008, thirty (5.1%) were confirmed as ESBL-producers; the majority (60%) of which produce CTX-M type ESBLs. Most (89%) ESBL producers co-express resistance to quinolones, 61% are susceptible to aminoglycosides and all remained susceptible to carbapenems.



Extended spectrum β-lactamases (ESBLs) are plasmid encoded enzymes that confer resistance to broad-spectrum cephalosporins and monobactams (Bradford 2001). They are commonly produced by Escherichia coli and Klebsiella species, but they are also found in other bacteria (Paterson & Bomono 2005). The presence of ESBLs poses as a threat in clinical settings because the ESBL genes are located in plasmids which can be easily transferred to non-ESBL isolates. . . . . . . . . . . . . . . .





BOMASANG ES, MENDOZA MT. 2003. Prevalence and risk factors associated with extended spectrum β-lactamase production among selected Enterobacteriaceae isolates at the Philippine General Hospital. Phil J Microbiol Infect Dis 32(4): 151-158.

BONNET R, SAMPAIO JLM, LABIA R, DE CHAMPS C, SIROT D, CHANAL C, SIROT J. 2000. A Novel CTX-M β-Lactamase (CTX-M-8) in cefotaxime-resistant Enterobacteriaceae isolated in Brazil. Antimicrob Agents Chemother 44(7): 1936-42.

BRADFORD PA. 2001. Extended-spectrum β-lactamases in the 21st Century: characterization, epidemiology, and detection of this important resistance threat. Clin Microbiol Rev 14: 933-51.

CABRERA EC, RODRIGUEZ RD. 2009. First report on the occurrence of SHV-12 extended-spectrum β-lactamase-producing Enterobacteriaceae in the Philippines. J Microbiol Immunol infect 42(1): 74-85.

[CLSI] Clinical and Laboratory Standards Institute. 2009. Performance Standards for Antimicrobial Disk Susceptibility Tests; Approved Standard. 9th ed. Pennsylvania, USA: Clinical and Laboratory Standard Institute. M2-A9, Vol. 26 no. 1. 53p.

GNIADKOWSKI M, PA A, UCHA, PAWE, GRZESIOWSKI, HRYNIEWICZ W. 1998. Outbreak of ceftazidime-resistant Klebsiella pneumoniae in a pediatric hospital in Warsaw, Poland: clonal spread of the TEM-47 extended-spectrum β-Lactamase (ESBL)- producing strain and transfer of a plasmid carrying the SHV-5-Like ESBL-encoding gene. Amtimicrob Agents Chemother 42(12): 3079-85.

HAWKEY PM. 2008. Prevalence and clonality of extended-spectrum β-lactamases in Asia. Clin Microbiol Infect 14: 159-165 (Suppl. 1).

HIRAKATA Y, MATSUDA J, MIYAZAKI Y, KAMIHIRA S, KAWAKAMI S, MIYAZAWA Y, ONO Y, NAKAZAKI N, HIRATA Y, INOUE M, TURNIDGE JD, BELL JM, JONES RN, KOHNO S. 2005. Regional variation in the prevalence of extendedspectrum β-lactamase-producing clinical isolates in the Asia-Pacific Region (SENTRY 1998–2002). Diagn Microbiol Infect Dis 52: 323-329.

JACOBY GA, MARTINEZ-MARTINEZ L. 1998. Quinolone resistance from a transferable plasmid. Lancet 351: 797-799.

LAUTENBACH E, STROM BL, BILKER WB, PATEL JB, EDELSTEIN PH, FISHMAN NO. 2001. Epidemiological investigation of fluoroquinolone resistance in infections due to extended-spectrum β-lactamase–producing Escherichia coli and Klebsiella pneumoniae. Clin Infect Dis 33: 1288-94.

PATERSON DL, BONOMO RA. 2005. Extended spectrum β-lactamases: a clinical update. Clin Microbiol Rev 18: 657-86.

PITOUT JD, HANSON ND, CHURCH DL, LAUPLAND KB. 2004. Population-based laboratory surveillance for Escherichia coli-producing extended-spectrum β-lactamases: importance of community isolates with blaCTX-M genes. Clin Infect Dis 38: 1736-41.

RASHEED JK, ANDERSON GJ, YIGIT H, QUEENAN AM, DOMÉNECH-SÁNCHEZ A, SWENSON JM, BIDDLE JW, FERRARO MJ, JACOBY GA, TENOVER FC. 2000. Characterization of the extended-spectrum β-Lactamase reference strain, Klebsiella pneumoniae K6 (ATCC 700603), which produces the novel enzyme SHV-18. Antimicrob Agents Chemother 44 (9): 2382-88.

ROSSOLINI GM, D’ANDREA MM, AND MUGNAIOLI C. 2008. The spread of CTX-M-type extendedspectrum β-lactamases. Clin Microbiol Infect 14 (Suppl. 1): 33-41.

THOMSON KS, SANDERS CC. 1992. Detection of extended-spectrum β-lactamases in members of the family Enterobacteriaceae: comparison of the doubledisk and three-dimensional tests. Antimicrob Agents Chemother 36: 1877-82.

VILLANUEVA FD, TUPASI TE, ABIAD HG, BAELLO BQ, CARDAÑO RC. 2003 Extended-spectrum β-lactamase production among Escherichia coli and Klebsiella spp. at the Makati Medical Center: tentative solutions. Phil J Microbiol Infect Dis 32(3): 103-108.