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Year : 2014  |  Volume : 32  |  Issue : 1  |  Page : 97--98

Multidrug resistant Gram-negative bacilli from neonatal septicaemia at a tertiary care centre in North India: A phenotypic and genotypic study

R Srivastava1, J Agarwal1, S Srivastava1, M Kumar1, M Singh2,  
1 Department of Microbiology, King George's Medical University, Lucknow, Uttar Pradesh, India
2 Department of Pediatrics, King George's Medical University, Lucknow, Uttar Pradesh, India

Correspondence Address:
J Agarwal
Department of Microbiology, King George«SQ»s Medical University, Lucknow, Uttar Pradesh

How to cite this article:
Srivastava R, Agarwal J, Srivastava S, Kumar M, Singh M. Multidrug resistant Gram-negative bacilli from neonatal septicaemia at a tertiary care centre in North India: A phenotypic and genotypic study.Indian J Med Microbiol 2014;32:97-98

How to cite this URL:
Srivastava R, Agarwal J, Srivastava S, Kumar M, Singh M. Multidrug resistant Gram-negative bacilli from neonatal septicaemia at a tertiary care centre in North India: A phenotypic and genotypic study. Indian J Med Microbiol [serial online] 2014 [cited 2020 Jul 16 ];32:97-98
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Dear Editor,

Neonatal septicaemia is a leading cause of morbidity and mortality in developing countries. Prompt treatment with appropriate antibiotics is necessary to reduce mortality and complications. [1] In an attempt to know the antibiotic resistance and prevalent mechanisms amongst Gram-negative bacilli (GNB) associated with neonatal septicaemia, 1474 (non-repetitive) blood culture samples from Neonatal Unit and Neonatal Intensive Care Unit collected between July 2011 and June 2012 were prospectively analysed. Antimicrobial susceptibility and screening/confirmatory tests for extended spectrum β-lactamase (ESBL) were performed as per Clinical Laboratory Standards Institute guidelines. [2] Metallo β-lactamase (MBL) production by ethylenediaminetetraacetic acid disc synergy test (EDST), [3] minimum inhibitory concentration (MIC) for meropenem and colistin, [2] phenotypic tests for AmpC production (by cefoxitin disc, [3] disc antagonism test, [3] boronic acid inhibition test [4] and ceftazidime-imipenem antagonism test) [5] and test for presence of efflux pump were performed. [6] Multiplex polymerase chain reaction (PCR) for CTX-M gene 1, 2, 8, 9 and 25 [7] and bla IMP-1 , bla IMP-2 , bla VIM-1 and bla VIM-2 of carbapenemases genes were done. [6]

A total of 273 (non-repetitive) bacterial isolates were obtained; comprising coagulase negative staphylococci (38.4%), Acinetobacter baumannii (16.4%), Staphylococcus aureus (15.7%), Klebsiella pneumoniae (9.1%), Candida sp. (6.2%), Pseudomonas aeruginosa (6.5%), Escherichia coli (4.7%), Citrobacter freundii (1.8%) and Enterobacter cloacae (0.73%). From amongst 108 GNB isolated, quarter were multidrug resistant (MDR; resistance to >3 groups of antibiotics). 48/108 GNB (44.4%) were meropenem resistant, MIC for these ranged between 4 and 28 μg/ml; isolates with higher MIC showed the presence of efflux pump. There were 33 ESBL producers and 34 were positive by EDST; 12 were both ESBL and MBL producers. Only one P. aeruginosa isolate produced AmpC (boronic acid inhibition test). Five P. aeruginosa (MIC ≥ 8 μg/ml) and 10 A. baumanii (MIC ≥ 4 μg/ml) were resistant to colistin. CTX-M-Group 1 was present in 17 GNB isolates, bla IMP-1 and bla VIM-2 in 9 and 2 isolates respectively, with one isolate carrying both the genes. In our study, EDST failed to detect all MBL producers as shown by PCR [Table 1].{Table 1}

Reports from developing countries show GNB to be the major etiological agents (~60%) of neonatal sepsis with K. pneumoniae being most common. [1] In our study however, A. baumannii was the most common GNB (45/108; 41.6%) with Gram-positive cocci in overall majority. Coexistence of various resistance mechanism including production of ESBL, MBL and AmpC β-lactamases and efflux pumps have led to MDR status amongst bacteria. [8] In the present study, one-fourth of the GNB isolated were MDR and ESBL prevalence was 30.5%, studies however have reported up to 72% ESBL producers in amongst GNB causing neonatal sepsis from India. [9] AmpC β-lactamase does not seem to be a major resistance mechanism in our setting. Colistin resistance seems to be higher amongst P. aeruginosa and A. baumannii at our centre. 31.5% GNB were MBL producers; much higher than what has been reported earlier. [8] In the present study, more than half of the ESBL producers carried CTX-M Group 1. The three C. freundii isolates were all MDR and carried CTX-M gene, a finding reported from other countries as well in recent years. [10]

In conclusion, we have highlighted changes in the bacterial aetiology of neonatal septicaemia, with non-fermenters emerging as important pathogens. Overall, prevalence of β-lactamases was low in our setting but closely linked to MDR status. It is important to understand local epidemiology for better implementation of infection control policies.


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