New Delhi Metallo-ß-lactamase and other mechanisms of carbapenemases among Enterobacteriaceae in rural South India.

OBJECTIVES: The emergence and dissemination of carbapenem-resistant Enterobacteriaceae (CRE) is an important public health problem. This study aimed to understand the prevalence and mechanisms of carbapenem resistance in clinically important members of Enterobacteriaceae in rural South India. METHODS: Routine clinical isolates of Escherichia coli and Klebsiella spp. were tested for Ertapenem (ETP) non-susceptibility by the disk diffusion method over a 3-year period (2012-2014). The ETP non-susceptible isolates were preserved, and tested for the MIC of carbapenems and the carriage of major carbapenemase-encoding genes. Representative genes were sequenced and selective isolates were tested for the production of carbapenemase by carbapenem inactivation method. RESULTS: A total of 444 ETP non-susceptible isolates were identified in increasing incidence over the study period. Among them, MIC50 and MIC90 of carbapenems (excluding ETP) were 0.25-0.5µg/mL and 8-16µg/mL, respectively, and the prevalence of non-ETP carbapenem resistance was estimated as 3%. Among the 177 tested isolates, 65 (37%) had one or more carbapenemase-encoding genes with a predominance of New Delhi Metallo-ß-lactamase (NDM; 32 of 65; 49.2%). CONCLUSIONS: This study documented the MIC range for carbapenems, prevalence and mechanisms of carbapenem resistance among Enterobacteriaceae in rural South India. It substantiated NDM as a leading mechanism of carbapenem resistance and highlighted the importance of MIC testing in patient management.

Validation of novel cost-effective antimicrobial gradient strips for the determination of carbapenem susceptibility in Enterobacteriaceae.

OBJECTIVES: The aim of this study was to validate the use of LML antimicrobial gradient strips for quantitative determination of carbapenem susceptibility in Enterobacteriaceae. METHODS: A total of 95 non-redundant Enterobacteriaceae strains isolated during 2012-2014 were used for this validation study. Initially, LML antimicrobial gradient strips were validated for their performance in comparison with the agar dilution method. The test strip was then validated in comparison with broth microdilution (BMD) and Etest with 24 selected strains using the same inocula and other laboratory parameters. RESULTS: The LML strip showed 83%, 68% and 86% essential agreement (within ±1 log2 dilution) with the reference methods of agar dilution, BMD and Etest, respectively; furthermore, essential agreement was >90% within ±2 log2 dilution. Categorical agreement was ≥87% with all reference methods according to Clinical and Laboratory Standards Institute (CLSI) and European Committee on Antimicrobial Susceptibility Testing (EUCAST) breakpoints. However, the meropenem strip requires performance improvements to fulfil US Food and Drug Administration (FDA) and International Organization for Standardization (ISO) requirements for an antimicrobial susceptibility test device. CONCLUSIONS: In LML antimicrobial gradient strip minimum inhibitory concentrations (MICs) were comparable with Etest MICs and it might serve as a reasonable, cost-effective alternative to Etest for quantitative determination of carbapenem susceptibility in Enterobacteriaceae.

Prevalence of antimicrobial resistance in Escherichia coli and Klebsiella spp. in rural South India.

The emergence and dissemination of antimicrobial resistance (AMR) is an important public health problem as resistant organisms cause difficult-to-treat infections. In this study, the prevalence of AMR in Escherichia coli and Klebsiella spp. in rural South India was examined in order to aid empirical therapy. A cross-sectional prospective study was conducted during the period from January 2012 to December 2014. Routine clinical isolates of E. coli and Klebsiella spp. were tested for antimicrobial susceptibility to ß-lactams, aminoglycosides, fluoroquinolones, tetracyclines, colistin and nitrofurantoin by the Kirby-Bauer disk diffusion method and the data were documented and analyzed with one per patient analysis using WHONET software. A total of 2292 non-duplicate clinical isolates were recovered during the study period, including 1338 E. coli and 954 Klebsiella spp. The prevalence of AMR in the total isolates was as follows: amikacin, 17.3%; ertapenem, 14.4%; doripenem, 4.5%; colistin, 13.2%; and tigecycline, 4.1%. The study results indicate a high prevalence of carbapenem resistance in Klebsiella spp. especially from pus and urinary isolates, whilst the prevalence of aztreonam and fluoroquinolone resistance was very high in E. coli.

Recent trends in HIV prevalence in a remote setting of southern India: insights into arranging HIV control policies.

INTRODUCTION: Constant vigilance of the dynamics of HIV prevalence is important in estimating, regulating, and implementing prevention programs. The objective of this study was to investigate the trend in the prevalence of HIV infection over six years among specific demographic groups in the remote district of southern India. METHODOLOGY: All high-risk attendees of the Integrated Counseling and Testing Centre, Government Theni Medical College between April 2005 and December 2010 were included in this study. Characteristics including age, sex, place of residence, literacy, and HIV sero-status were collected as per the guidelines of the National AIDS Control Organization. RESULTS: A total of 50,043 data sets were analyzed; 3,282 (6.6%) tested positive for HIV infection. The prevalence of HIV infection among the ≤ 25 age group was significantly lower as compared to the elderly (4.4% vs. 6.9%; odds ratio 0.62; 95% confidence interval 0.55-0.71; p < 0.01). There was a decline in HIV prevalence among both age groups (P(trend) < 0.01 for ≤ 25 year-old; -82.3% and P(trend) < 0.01 for > 25-year old, -14.2%), males (P(trend) < 0.01; -50.9%), the urban population (P(trend) < 0.01; -45.9%), and illiterates (P(trend) < 0.01; -68%). The trend of HIV prevalence among females (P(trend) = 0.48; +9.1%), the rural population (P(trend) = 0.95; -7.1%), and literate population (P(trend) = 0.44; +28%) was statistically insignificant. CONCLUSION: HIV prevalence is stable in the female population, while it is decreasing in male population, indicating that current interventions must be strengthened to reduce HIV prevalence among females.