Detection of the classical G2576U mutation in linezolid resistant Staphylococcus aureus along with isolation of linezolid resistant Enterococcus faecium from a patient on short-term linezolid therapy: first report from India.

PURPOSE: Linezolid is an effective drug against methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant enterococci (VRE). We describe the emergence of linezolid resistance in MRSA and VRE from India. MATERIAL AND METHODS: One MRSA and two VRE strains were isolated from a patient on linezolid therapy of one week duration. All three isolates were resistant to linezolid with minimal inhibitory concentrations (MIC) ≥4 mg/L. The 746-bp region flanking the possible G2576U mutation on the corresponding DNA from the 23S rRNA was amplified by polymerase chain reaction (PCR) and amplicons were sequenced for all the three isolates. Conjugation experiments using the linezolid resistant MRSA (LRMRSA) and linezolid resistant VRE (LRVRE) isolates as donors and wild strains of corresponding genera as recipients were performed. RESULTS: The MRSA isolate had the classical G2576U mutation. High quality value scores in the sequencing software validated the mutation. Conjugation studies did not indicate presence of transferable resistance for linezolid. Sequencing did not indicate presence of any mutation in the two LRVRE isolates. CONCLUSIONS: This is the first report from India citing resistance in Staphylococcus and Enterococcus against Linezolid.

Zinc-dependent carbapenemases in clinical isolates of family Enterobacteriaceae.

PURPOSE: The emergence and spread of zinc-dependent carbapenem resistance has become a diagnostic challenge for clinical microbiologists. The objective of the present study was to screen zinc-dependent carbapenemase activity in clinical isolates of family Enterobacteriaceae. MATERIALS AND METHODS: A total of 102 multidrug-resistant organisms (MDROs), non-repeat clinical isolates of family Enterobacteriaceae from two tertiary care centres in Delhi, were screened for carbapenemase production by a modified Hodge test (MHT) and additionally by a re-modified Hodge test, EDTA double disc synergy test, and combined disc test (or disc enhancement test) to determine zinc dependence of carbapenemases harbouring bacteria. RESULTS: Of the total 102 clinical isolates (June through November 2010), 91 were from urine and 11 were from blood specimens. The isolates were obtained from patients visiting the outpatient department (18 isolates), admitted in non-ICU inpatient care units (74 isolates) and patients admitted in ICUs (4 isolates). MHT identified 92 (90.2%) isolates as carbapenemases producers. Among those found negative for MHT (n=10), metallo-beta-lactamases (MBLs) activity was demonstrated through the EDTA disc diffusion synergy test and the combined disc test in 8 and 9 isolates respectively. A total of 63 (61.7%) isolates demonstrated MBL activity despite in vitro sensitivity to Imipenem. CONCLUSIONS: The study demonstrated that supplementing the MHT with at least one of the screening methods increases the likelihood of picking up such isolates that may be missed by the MHT. The study also demonstrates the wide-spread presence of MBLs in Enterobacteriaceae members from patients visiting hospitals in east Delhi.

Cytokine response to dietary rehabilitation with curd (Indian dahi) & leaf protein concentrate in malnourished children.

BACKGROUND & OBJECTIVE: Protein energy malnutrition (PEM), an important cause of secondary immune deficiency, is associated with several abnormalities in the immune system including cytokine production. In the present study cytokine levels (both pro- and anti-inflammatory) were evaluated in protein energy malnourished children following nutritional rehabilitation with curd (Indian dahi) and leaf protein concentrate (LPC). METHODS: Eighty moderately and severely malnourished children, 1-5 yr of age, received the WHO recommended diet for severe malnutrition, modified according to local dietary habits, containing in addition either curd or micronutrient-rich leaf protein concentrate, for a period of 15 days. Cytokine levels [tumour necrosis factor alpha (TNFalpha), interferon gamma (IFNgamma), interleukin-10 (IL-10), interleukin-4 (IL-4)] were measured before and after dietary rehabilitation. RESULTS: The baseline cytokine levels (TNFalpha, IFNgamma, IL-10 and IL-4) were high in malnourished children. Both the diets caused an increase in serum pro-inflammatory (TNFalpha, IFNgamma), and anti-inflammatory (IL-10) cytokine levels after nutritional rehabilitation. The increase in IL-10 was significant in children receiving curd. There was an insignificant fall in IL-4 levels with both the diets. The cytokine response was comparable in children with moderate and severe malnutrition, as also in children < 2 yr to those between 2-5 yr. INTERPRETATION & CONCLUSION: The study suggests that cytokines (TNFalpha, IFNgamma, IL-10 and IL-4) may serve as biological markers to assess the effect of functional foods like curd or LPC on immunity in malnutrition. Curd may help to maintain the balance in cytokine production by increasing the production of IL-10, and may be considered in place of milk in the nutritional rehabilitation of malnourished children.