Diarrhea, common bacteria to produce Extended-spectrum ?-lactamases (ESBL) and

Diarrhea, Pneumonia, and other infectious diseases are leading causes of death among children younger than five years in low and middle -income countries and also in India (Black et al. 2003 and Bassani et al. 2010). However, little is known about the causes of death in children after age five years. The Global Burden of Disease and Risk Factors (GBD) estimates that in 2004 there were approximately 69,000 deaths from pneumonia and 1000 deaths from diarrheal diseases among children aged 5-14 years in India, (Lopez AD et al. 2006).

The vast majority of deaths due to pneumonia and diarrhea occur in the poorest regions–nearly 90 percent of them in sub-Saharan Africa and South Asia. About half the world’s deaths due to pneumonia and diarrhea occur in just five mostly poor and populous countries: India, Nigeria, the Democratic Republic of the Congo, Pakistan, and Ethiopia (Liu et al. 2012).

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Deaths among children under age 5 due to pneumonia and diarrhea are high in India. In 2005, 2.35 million deaths (Mortality Rate-85.8) were found. In North India, there is also high mortality rate. In 2005, 65.6 mortality rates were reported (Black et al. 2003 and Bassani et al. 2010).

Escherichia coli and Klebsiella pneumonia are two of the main causative agents of  most of the infectious diseases. These are common bacteria to produce Extended-spectrum ?-lactamases (ESBL) and plasmid-mediated quinolone resistance (PMQR), which of the main factor that confers resistance to these bacteria against beta-lactam and quinolone. And these resistance species are emerging clinical challenge for us.                     

 

                                     

                  Fig. 1: Causes of deaths in children under 5 years in India, 2005

Extended-spectrum ?-lactamases (ESBLs) have become widespread in a significant percentage of Gram- negative bacteria, especially in Enterobacteriaceae throughout the world (Bradford, 2001). Generally, the ESBLs are enzymes that arise by mutations in genes for common plasmid- mediated ?-lactamases, such as TEM-1, SHV-1, and OXA – 10, or may be distantly related to a native enzyme, as in the case of CTX-M ?-lactamases (Smet et al., 2009).

Usually, ESBLs are encoded by blaTEM, blaSHV or blaCTX-M genes in Enterobacteriaceae and other Gram-negative bacteria (Monstein et al., 2007). At the same time, plasmid-mediated quinolone resistance (PMQR) is also a threat to the veterinary clinical therapy and human public health. Fluoroquinolones are among the most commonly prescribed antimicrobials because of their broad-spectrum antimicrobial activity, and fluoroquinolone-resistant gram-negative pathogens have emerged worldwide. Quinolone resistance is traditionally mediated by the mutation of chromosomal genes encoding DNA gyrase and/or topoisomerase IV or by the mutation of genes regulating the expression of efflux pumps (Hooper, D. C. 1999, Hooper, D. C. 2000). To date, at least three types of PMQR determinants, including qnr families (qnrA, qnrB, qnrS, qnrC and qnrD), aac (60)-Ib-cr and quinolone efflux pump (qepA and oqxAB) have been extensively reported (Strahilevitz et al., 2009). Moreover, qnr genes have been commonly detected among isolates producing ESBLs (Robicsek et al., 2006) which raises the risk for transfer of multidrug-resistant Escherichia coli to humans.

It was thought that quinolone resistance could be acquired only by chromosomal mutations until plasmid-mediated resistance to quinolones was described in a clinical isolate of Klebsiella pneumonia in 1998 (Martinez-Martinez, L., A. Pascual, and G. A.

Jacoby. 1998). Since then, four major groups of qnr determinants, qnrA, qnrB, qnrC, and qnrS, have been identified (Jacoby, G., V. Cattoir, D. Hooper, L. Mart?´nez-Mart?´nez, P. Nordmann, A. Pascual, L. Poirel, and M. Wang. 2008, Wang, M., X. Xu, and S. Wu. 2008), and two additional plasmid-mediated quinolone resistance (PMQR) genes have been described— aac(6_)-Ib-cr, which encodes a variant aminoglycoside acetyltransferase that modifies ciprofloxacin (Robicsek, A., J. Strahilevitz, G. A. Jacoby, M. Macielag, D. Abbanat, K. Bush, and D. C. Hooper. 2006), and qepA, which encodes an efflux pump belonging to the major facilitator subfamily (Pe’richon, B., P. Courvalin, and M. Galimand. 2007). These PMQR determinants are increasingly being identified worldwide in clinical isolates of Enterobacteriaceae (Gay, K., A. Robicsek, J. Strahilevitz, C. H. Park, G. Jacoby, T. J. Barrett, F. Medalla, T. M. Chiller, and D. C. Hooper. 2006) and in clinical and environmental Aeromonas species isolates (Cattoir, V., L. Poirel, C. Aubert, C. J. Soussy, and P. Nordmann. 2008). The global occurrence of antibiotic resistance genes in bacteria found in aquatic environments is an increasing concern. Microorganisms that carry genes encoding resistance to a broad range of antibiotics have been found in hospital wastewater and excreted animal product as well as in sewage, surface water, river water, groundwater and drinking water (Zhang X et al., 2009). Aquatic environments are described as natural reservoirs of antibiotic-resistant bacteria (Ferreira et al., 2007).In addition, the presence of antibiotics and their metabolites in sewage may promote both the selection of resistant strains, and the horizontal transfer of antibiotic resistance genes (Andersen SR et al., 1993). All natural waters support and contain a variety of organisms, both plants, and animals as the natural flora and fauna.

Almost all the world’s water (97%) is located in the oceans, but as might be expected, the high concentration of salts renders the sea water  virtually unusable. 1.74% of water is present as glaciers and permanent snow and 0.3% is present as groundwater, stored in the aquifer both as confined and unconfined and is perched aquifers. The available freshwater content in terms of direct use is only thus limited to 1%. India is a developing nation facing a serious problem of natural resource scarcity, especially that of water in view of rapidly population growth and economic development. In India, water bodies are increasingly getting contaminated with sewage, domestic waste, industrial wastes;  and due to sociocultural activities. The bacteria causing cholera, typhoid fever and bacillary dysentery may be present in sewage water or polluted water. Polluted water also contains several pathogenic viruses, out of which the prominent one is the one causing infections such as hepatitis (jaundice) and poliomyelitis, etc. One should always keep a check on the presence of biological as well as chemical pollutants present in water. Municipal water and food products are routinely monitored for the presence of pathogens, but there are many challenges in doing so. Even non-pathogenic bacteria, if present in large enough numbers can cause deterioration of food products and water. The alternative for the testing of many different types of pathogens is to test for those bacteria that indicate the presence of pathogens. The most common source of pathogens in food and water is fecal contamination, of either animal or human origin. Feces also contain innumerable non-pathogenic bacteria, and the presence of these other bacteria in food or water indicates that fecal contamination has occurred and hence the presence of pathogens. Microbes are susceptible to antibiotics and most of the diseases of bacterial origin are treated with these antibiotics. But of late these pathogenic bacteria upon indiscriminate exposure to the antibiotics have started developing resistance towards them and thus posing an alarming scenario in the world of medical sciences. The presence of ESBL and PMQR in bacteria are yet other elements to the development and acquisition of antibiotic resistance among the pathogens. In this study, therefore I studied and investigated the occurrence of genetic elements responsible for the ESBL and PMQR in the fresh water bodies, and the river Yamuna in and around Delhi region to assess and predict the danger posed by the ESBL and PMQR pathogens particularly in E. coli and K pneumonia.

 

 

 

           Objectives:                      

·         Isolation and identification of E.coli and K. pneumonia from Yamuna water as well as sewage water in Delhi.

·         Antimicrobial susceptibility testing, and phenotypic detection of ESBL and PMQR.

·         To study the protein expression at different environmental stress condition.

·         To investigate the occurrence of ESBL and PMQR genes in above-selected isolates to reveal genetic variation among ESBL and PMQR.