|Year : 2015 | Volume
| Issue : 1 | Page : 191-192
CTX-M and PER-1 group extended spectrum β-lactamases-producing Pseudomonas aeruginosa from the patients of lower respiratory tract infection
S Saxena1, G Banerjee2, R Garg1, M Singh2
1 Department of Pulmonary Medicine , King George Medical University, Lucknow, Uttar P, India
2 Department of Microbiology , King George Medical University, Lucknow, Uttar Pradesh, India
|Date of Submission||28-Nov-2013|
|Date of Acceptance||13-Feb-2014|
|Date of Web Publication||5-Jan-2015|
Department of Microbiology , King George Medical University, Lucknow, Uttar Pradesh
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Saxena S, Banerjee G, Garg R, Singh M. CTX-M and PER-1 group extended spectrum β-lactamases-producing Pseudomonas aeruginosa from the patients of lower respiratory tract infection. Indian J Med Microbiol 2015;33:191-2
|How to cite this URL:|
Saxena S, Banerjee G, Garg R, Singh M. CTX-M and PER-1 group extended spectrum β-lactamases-producing Pseudomonas aeruginosa from the patients of lower respiratory tract infection. Indian J Med Microbiol [serial online] 2015 [cited 2020 Jul 6];33:191-2. Available from: http://www.ijmm.org/text.asp?2015/33/1/191/148444
Pseudomonas aeruginosa is reported to be among the leading causes of nosocomial infections. It is known to exhibit intrinsic resistance to several antimicrobial agents.  extended-spectrum β-lactamases (ESBLs) are an important cause of bacterial resistance throughout the world.  PER-1 (Pseudomonas-extended resistant) ESBL is an Ambler class A β-lactamase that was first described in France in 1991 in a P. aeruginosa-isolate recovered from a Turkish patient.  and CTX-M-1-producing P. aeruginosa isolate has been reported from the Netherlands  as well as CTX-M-2-positive P. aeruginosa isolates in Bolivia. 
In this study period, we describe the presence of ESBL genes in sputum isolates of P. aeruginosa between May 2012 and December 2012. We obtained a total of 100 samples from LRTI patients. LRTI patients of ≥18-years age with symptoms suggestive of LRTI (i.e., two or more of the following symptoms: cough, sputum production, shortness of breath, wheeze, fever during this illness, chest pain), who gave written informed consent for participation and a sputum sample for examination were enrolled for the study.
Antimicrobial susceptibility and screening/confirmatory tests for extended spectrum β-lactamase were done as per CLSI guidelines.  Minimum inhibitory concentration (MIC) for all ceftazidime-resistant strains were performed.  Multiplex PCR for CTX-M gene 1, 2, 9  and blaPER genes was done by PCR. 
Out of 100 sputum samples which were cultured, 47 yielded the pure growth of P. aeruginosa were tested for ESBL production. Thirty-five strains showed resistance to ceftazidime, of which 24 (51.06%) were found to be ESBL producers. Among the 35 (74.5%) ceftazidime-resistant P. aeruginosa, 15 (42.8%) were ESBL producers by CDT and only 9 (25.7%) were positive by DDAT.
Out of 24 isolates were confirmed as ESBL producers, seven were positive for the blaCTX genes and four isolates tested were positive for the PER gene by PCR. blaCTX M-2 was detected in five isolates, blaCTX-M-1 was detected in two and, bla CTX-M-9 genes were not detected [Table 1].
|Table 1: Characteristics of multidrug - resistant Pseudomonas aeruginosa utum isolates |
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ESBL detection methods for P. aeruginosa are unreliable, and generally low because of mutational derepression of the chromosomally mediated AmpC enzyme, up-regulation of efflux systems and decreased outer membrane permeability. 
In our study, the antibiogram of the 47 isolates of P. aeruginosa showed that more resistance against ceftazidime (74.5%), which was similar to the observations which were by Ibukun et al., who reported a higher susceptibility for ceftazidime of 79.4%. 
The first description of the presence of CTX-M ESBLs in P. aeruginosa and Stenotrophomonas maltophili reported by Al Naiemi et al. In this study, the presence of CTX-M-1β- lactamase in seven sputum isolates of P. aeruginosa. ESBL-producing strains are usually found in those areas of hospitals where antibiotic use is frequent and the patient's condition is critical. Among ESBL producers, blaCTX-2 was the most common gene (20.8%) identified.
These resistant organisms are clinically important because they result in increased morbidity and mortality. The association of CTX-M β-lactamase-encoding genes with mobile elements such as the ISEcp1 insertion element and integrons may facilitate the spread of blaCTX-M genes among bacteria. 
The high frequency of ESBLs production in our work indicates the necessity for monitoring ESBL-producing strains of P. aeruginosa. This finding is important to understand local epidemiology for better implementation of infection control measures.
| ~ Acknowledgments|| |
This work was supported by Indian council of medical research (ICMR), 80/712/11-ECDI-Delhi.
| ~ References|| |
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