Regional variations in antimicrobial susceptibility of community-acquired uropathogenic Escherichia coli in India: Findings of a multicentric study highlighting the importance of local antibiograms.

Objectives: Evidence-based prescribing is essential to optimize patient outcomes in cystitis. This requires knowledge of local antibiotic resistance rates. Diagnostic and Antimicrobial Stewardship (DASH) to Protect Antibiotics (https://dashuti.com/) is a multicentric mentorship program guiding centers in preparing, analyzing and disseminating local antibiograms to promote antimicrobial stewardship in community urinary tract infection. Here, we mapped the susceptibility profile of Escherichia coli from 22 Indian centers. Methods: These centers spanned 10 Indian states and three union territories. Antibiograms for urinary E. coli from the outpatient departments were collated. Standardization was achieved by regional online training; anomalies were resolved via consultation with study experts. Data were collated and analyzed. Results: Nationally, fosfomycin, with 94% susceptibility (inter-center range 83-97%), and nitrofurantoin, with 85% susceptibility (61-97%), retained the widest activity. The susceptibility rates were lower for co-trimoxazole (49%), fluoroquinolones (31%), and oral cephalosporins (26%). The rates for third- and fourth-generation cephalosporins were 46% and 52%, respectively, with 54% (33-58%) extended-spectrum ß-lactamase prevalence. Piperacillin-tazobactam (81%), amikacin (88%), and meropenem (88%) retained better activity; however, one center in Delhi recorded only 42% meropenem susceptibility. Susceptibility rates were mostly higher in South, West, and Northeast India; centers in the heavily populated Gangetic plains, across north and northwest India, had greater resistance. These findings highlight the importance of local antibiograms in guiding appropriate antimicrobial choices. Conclusions: Fosfomycin and nitrofurantoin are the preferred oral empirical choices for uncomplicated E. coli cystitis in India, although elevated resistance in some areas is concerning. Empiric use of fluoroquinolones and third-generation cephalosporins is discouraged, whereas piperacillin/tazobactam and aminoglycosides remain carbapenem-sparing parenteral agents.

Bacterial abundance and antimicrobial resistance patterns of uropathogens among pregnant women with asymptomatic bacteriuria: Association with glycemic status.

Objectives: Antimicrobial resistance (AMR), a growing global menace, poses a significant threat to maternal and fetal health. Gestational diabetes mellitus (GDM) causes double trouble in pregnancy, increasing the risk of a variety of infectious morbidities while also raising the possible association with AMR. Asymptomatic bacteriuria (ASB) is a common problem in pregnancy, but little research has been done to date explicitly examining the relationship between GDM and ASB and yielded conflicting results. Even fewer studies have specifically examined the relationship between GDM and AMR in women with ASB. Retrieving the most recent information on the disease burden, the range of causative pathogens, their patterns of AMR, and associated risk factors in pregnant women is crucial to stop the exponential rise in AMR in pregnancy and improve maternal and neonatal outcomes of infectious morbidities. Hence, this study was planned to investigate the association between glycemic status and the contemporary bacterial profile, antimicrobial resistance(AMR), and associated variables among pregnant women with ASB. Study design: This prospective, hospital-based, cross-sectional study was conducted among 320 pregnant women; divided into two groups, GDM and non-GDM. Data regarding sociodemographic and clinical characteristics were collected using a structured questionnaire. Clean-catch midstream urine samples were investigated for the presence of significant bacterial uropathogens and their AMR pattern was determined using recommended culture methods. Results: We found ASB in 46.25% of study participants with significantly higher occurrence in the GDM group. Dominant isolates were Escherichia coli followed by Klebsiella pneumoniae. AMR was noted in 51.35% and multidrug resistance(MDR) in 23.65% of isolates. Overall AMR, MDR and higher degrees of AMR were higher among uropathogens isolated from the GDM group as compared to the non GDM group, although the difference was not statistically significant. Conclusion: The high occurrence of ASB in pregnancy along with substantially high AMR in this study suggests the need for effective infection control and stewardship programmes. By defining the association of ASB and AMR with hyperglycemia, our study calls for the exploitation of this potential association in halting the pandemic of AMR and in improving the management of infectious morbidities, thus in-turn alleviating their undesired maternal and infant outcomes.

An insight into genes responsible for fosfomycin resistance among uropathogens of asymptomatic bacteriuria during pregnancy: A North Indian study.

Purpose: Asymptomatic bacteriuria (ASB) is a common finding during pregnancy. Effective antibiotic treatment could reduce its adverse effects on both mother and fetus. However, emerging antimicrobial resistance limits the treatment options. Fosfomycin might be a promising drug in this regard, as its resistance is still low. The aim of the study was to determine the antimicrobial susceptibility pattern of fosfomycin in isolates causing ASB by disc diffusion and agar dilution (in selected isolates), determine minimum inhibitory contribution (MIC) by agar dilution in isolates resistant by disc diffusion and detect the genes responsible for fosfomycin resistance. Methods: This was a 2-year study carried in the Department of Microbiology, Jawaharlal Nehru Medical College and Hospital (JNMCH), Aligarh Muslim University (AMU), Aligarh. A total of 10 252 urine samples from asymptomatic pregnant females (18-45 years) attending the antenatal care (ANC) outpatient department (OPD) were submitted. Identification of pathogen and antimicrobial susceptibility testing (AST) was carried out as per standard methods of CLSI. There was phenotypic detection of methicillin-resistant Staphylococcus aureus (MRSA) and other Staphylococcus species (MRSS), high-level aminoglycoside resistance (HLAR), vancomycin resistant Enterococci (VRE) and S. aureus (VRSA), extended spectrum ß-lactamase (ESBL) and carbapenem-resistant Enterobacterales (CRE). All the fosfomycin-resistant isolates (by disk diffusion) were tested by agar dilution. Conventional PCR was performed for murA, fosA, uhpT and glpT genes on all resistant isolates. Result: In this study, the prevalence of ASB among pregnant females was 1173(11.4 %), in which Escherichia coli 495(42 %) was the predominant organism. The overall sensitivity of fosfomycin among Gram-positive cocci (GPC) and Gram-negative bacilli (GNB) was 99 % and 97.6 %, respectively. MRSA and MRSS accounted for 50 (66.6 %) and 71 (76 %), respectively. The highest rates of MIC >2048 µg ml-1 were shown by most isolates (mainly E. coli ) on agar dilution. PCR studies revealed four E. coli strains possessed both murA (also present in one K. pneumoniae strain) and glpT genes. While only one isolate ( E. faecalis ) was positive for fosA gene. But none of the strain possessed the uhpT gene. Conclusion: According to this study, murA and glpT genes were more frequent than fosA. We cannot comment on the prevalence and regional distribution of fosfomycin-resistant genes based on this preliminary study. Therefore, more Indian studies should be carried out to create awareness about the presence of genes in a particular area.

Bacteriological and Antibiotic Sensitivity Profile of Cholesteatomatous Otitis Media in Pediatric and Adult Population: Prevailing Scenario in Northern India.

The bacteriological and antimicrobial sensitivity profile of chronic otitis media (COM) varies from region to region and from time to time and may vary among different age group as well. It was against this backdrop of the changing bacteriological profile and sensitivity pattern together with the paucity of categorically separated data of pediatric and adult population, that the present study was undertaken. A total of 193 patients of clinical diagnosis of cholesteatomatous COM with ear discharge and positive culture results were included in the study. Pus sample was collected under aseptic conditions and cultured on solid media and broth. Isolates were identified via standard biochemical tests and sensitivity patterns analysed. Chi square (χ2) test was used to analyse the significance. Pseudomonas was the most common isolate in both the pediatric (37.80%) and adult (51.46%) population. Methicillin sensitive staph aureus (MSSA) was found exclusively in pediatric population (p = 0.003).Piperacillin-Tazobactam combination was the single most effective drug regimen overall. 75% of pseudomonas isolates in pediatric and 87.5% in adults were sensitive to this regimen in vitro. Amikacin was the next most effective drug with 56.69% sensitivity in pediatric and 64.08% sensitivity in adult population. The present study finds piperacillin-tazobactam as the most effective therapy and pseudomonas as the most common isolate in the study population.In order to address the varying and changing bacteriological and sensitivity profile of chronic otitis media occurring among different geographical regions and also within a region over time, the authors recommend its periodic evaluation.

Microbiological Assessment of Chronic Otitis Media: Aerobic Culture Isolates and Their Antimicrobial Susceptibility Patterns.

As there are changing trends in the microbiology of chronic otitis media, this study was carried out to look for the current aerobic microbes and their antimicrobial susceptibilities in patients of chronic otitis media from north Indian region. A total of 322 patients who met the inclusion criteria were studied and aerobic ear swab culture was done under aseptic conditions. Gram staining was performed and antibiotic susceptibility testing was done using Kirby-Bauer disc diffusion method on Mueller-Hinton Agar. A total of 341 culture positive results were obtained from 322 patients. The culture results revealed 10 different aerobic microbes. Gram-positive floras were seen in 152 (44.57%), and Gram-negative in 189(55.43%) isolates. Staphylococcus aureus was the most common isolate present in 131 samples (38.41%), followed by pseudomonas aeruginosa in 101 (29.62%) and proteus in 36 (10.56%). In overall susceptibility of antibiotics against Gram-positive culture isolates, Vancomycin was most effective (97.37%). For Gram-negative microbes, Piperacillin-Tazobactum combination was most effective with overall susceptibility of 79.37% susceptibility. Microbiological assessment of Chronic Otitis Media should be carried out in an area on regular intervals because of the changing patterns of bacteriology and their antimicrobial susceptibilities.

Reliability of carbapenem inactivation method (CIM) and modified carbapenem inactivation method (mCIM) for detection of OXA-48-like and NDM-1.

PURPOSE: Carbapenem inactivation method (CIM) and modified carbapenem inactivation method (mCIM) were recently developed for rapid detection of carbapenemase producing Gram negative bacilli (CP-GNB). In this study we compared the ability of modified Hodge test (MHT), CIM and mCIM to identify CP-GNB in Oman and India. METHODS: Fifty fully characterized and genotyped CP-GNB (26 OXA-48-like, 2 NDM-1 from Oman and 22 NDM-1 from India) and 8 AmpC as controls in India were subjected to MHT, CIM, mCIM and mCIM with in-house modifications. Wilcoxon paired test and receiver operating characteristics (ROC) were utilised for statistical analysis. RESULTS: Isolates were predominantly OXA-48-like genes producing Klebsiella pneumoniae from Oman and NDM-1 producing Escherichia coli from India. MHT was positive in all except one OXA-48-like producers and in 70.8 â€‹% of the NDM-1 isolates. The sensitivity of CIM in detecting 0XA-48 like and NDM-1 carbapenemases were 39.2% and 87.5% respectively. mCIM at 4 â€‹h detected 92.3 â€‹% and 79.1% of 0XA-48 and NDM-1 respectively. Using receiver operative characteristics (ROC), highest sensitivity and specificity for detection of OXA-48-like was obtained by mCIM at 4 â€‹h at cut off 17 â€‹mm while for NDM-1 CIM was the test of choice at 16 â€‹mm. CONCLUSION: CIM and mCIM are simple, cheap and easy tests to perform. CIM gave excellent results with NDM1 strains while it was quite poor in predicting OXA-48-like. We recommend CIM and eCIM for rapid identification of NDM-1 producers and mCIM at 4 â€‹h and MHT for detection of OXA-48-like. No one method can correctly detect both genotypes. As determined by ROC curves a zone of inhibition of 17 â€‹mm was considered adequate for detection of OXA-48-like and 16 â€‹mm of NDM-1 by mCIM at 4 â€‹h and CIM respectively.

Qualitative Thematic Analysis of Knowledge and Practices of Surgical Antimicrobial Prophylaxis at a Tertiary Care Teaching Hospital.

Background: Surgical antimicrobial prophylaxis (SAP) refers to the utilization of antibiotic agents for the prevention of surgical site infections (SSI), to prevent SSI-associated morbidity and mortality, reduce duration and cost of healthcare, and cause minimal adverse drug effects. The adherence rate among surgeons for the available international and national guidelines and optimal practice remains considerably low in many hospitals, especially in developing countries. The objective of this study was to assess the knowledge and compliance rate for SAP guidelines among various surgical specialties and those involved in providing SAP. Methods: An institution-based exploratory, multi-specialty, collective, mixed method approach (qualitative and quantitative) was used to assess the knowledge and compliance rate for SAP guidelines among the consultants and residents of surgical specialties. Quantitative analysis was performed using a pre-tested questionnaire. For qualitative analysis, focus group discussions were conducted. Thematic analysis was conducted by the Theoretical Domains Framework (TDF) and the Capabilities, Opportunities, Motivation and Behaviour (COM-B) model. Results: Twenty-eight focus groups and 16 paired interviews were undertaken. On thematic analysis six significant themes were noted and mapped to the COM-B model, and subthemes mapped to the relevant TDF domains in a combined framework. Key themes recognized were: (1) solitary focus on surgical skills; (2) following the hierarchy is more important than guideline compliance; (3) doubts and overcautious attitude of surgeons hinders appropriate SAP prescribing; (4) non-availability in-hospital supply of antimicrobial agents; (5) patient characteristics and type of surgery play a role in prescribing SAP; and (6) lack of national and local guidelines. Conclusions: The knowledge and attitudes of surgeons toward appropriate SAP prescribing are crucial factors for execution of guidelines. Including them in policy making decisions can help in strong execution of the same.

Molecular characterization and phylogenetic analysis of human pathogenic Leptospira species circulating in a tertiary care hospital of Western Uttar Pradesh in India.

Leptospirosis is identified as an important reemerging zoonotic disease distributed worldwide, caused by Leptospira. This study was carried out to explore the genetic characterization and its phylogenetic analysis of circulating Leptospira species, among the Aligarh region of western Uttar Pradesh in India, utilizing secY gene-based nucleotide sequence. A total of 190 human samples were included in the study. Positive samples were identified by ELISA, MAT and PCR. MAT was carried out utilizing local circulating Leptospira serovars. Four positive samples including two MAT positive samples were subjected to DNA sequencing for further confirmation and phylogenetic tree was constructed. Out of the total of 190 samples, 24 patients were found positive by ELISA and 29 by PCR. Two samples were found reactive in MAT with L. interrogans serovars like hebdomadis and copenhageni. Phylogenetic analysis of four isolates based on partial secY gene nucleotide sequences revealed that species obtained from the Aligarh region clustered with the several published pathogenic Leptospira interrogans, while some of our isolates nucleotide sequences also clustered with the published sequence of intermediate and saprophytic Leptospira serovars like Leptospira inadai and Leptospira meyeri. This pilot study will help us to decipher the present scenario of circulating serovars of leptospira as well as to identify the nucleotide changes in secY gene, in this region.

Prevalence of scrub typhus in pyrexia of unknown origin and assessment of interleukin-8, tumor necrosis factor-alpha, and interferon-gamma levels in scrub typhus-positive patients.

BACKGROUND: Scrub typhus is lesser known cause of fever of unknown origin in India. Even if there have been reports documenting the prevalence of scrub typhus in different parts of India, it is still an unknown entity, and clinicians usually do not consider it as differential diagnosis. The present study was performed to document the prevalence of scrub typhus among febrile patients in western part of Uttar Pradesh and to assess the clinical profile of infected patients on the one hand and knowledge, attitude, and practices among clinicians on the other. MATERIALS AND METHODS: A total of 357 adult patients with fever of more than 5-day duration were recruited. All patients underwent complete physical examination, and detailed clinical history was elicited as per predesigned pro forma. After primary screening to rule out malaria, enteric fever, and leptospirosis infection, secondary screening for scrub typhus was done by rapid screen test and IgM ELISA. RESULTS: Scrub typhus infection was positive in 91 (25.5%) cases. The most common symptoms among the patients were fever (100%), pain in abdomen (79.1%), pedal edema 56 (61.5%), rash 44 (48.3%), headache 44 (48.3%), vomiting 42 (46.1%), constipation 33 (36.2%), cough 28 (30.7%), and lymphadenopathy 20 (21.9%). The median values of interleukin-8, interferon-gamma, and tumor necrosis factor-alpha in healthy controls were 15.54 pg/ml, 7.77 pg/ml, and 54.1 pg/ml, respectively, while the median values of these cytokines in scrub typhus-positive patients were 21.04 pg/ml, 8.74 pg/ml, and 73.8 pg/ml, respectively. CONCLUSION: Our results highlight that scrub typhus infection is an important cause of pyrexia of unknown origin, and active surveillance is necessary to assess the exact magnitude and distribution of the disease.

Increasing antimicrobial resistance among uropathogens: Is fosfomycin the answer?

INTRODUCTION: Urinary tract infection (UTI) is one of the most common infectious diseases in clinical practice. The choice of antibiotics for the treatment of UTI is limited by the rising rates of antibiotic resistance. There is an urgent need to discover new effective treatment solutions. Fosfomycin may be an interesting alternative to the currently used treatments of UTIs. MATERIALS AND METHODS: The study was conducted over 6 months period (January to June 2013) in Department of Microbiology, JNMCH, AMU, Aligarh. A total of 1840 urine samples were submitted. Culture and sensitivity was done as per standard microbiological procedures. Methicillin-resistant Staphylococcus aureus (MRSA), high-level aminoglycoside resistance (HLAR), extended spectrum beta-lactamases (ESBL), AmpC and metallo-beta-lactamases (MBL) production was detected. RESULTS: Culture was positive in 504 (27.4%) cases. Gram-negative etiology was identified in 390 (73%) cases. ESBL production was detected in 154 (37.1%) while 82 (21.6%) were Amp C. No, MBL was detected. Among Gram-positive bacteria, 68 (51.5%) were MRSA, while 4 (13.3%) were vancomycin resistant enterococci (VRE). HLAR was seen in 53.3% of enterococci. Fosfomycin was effective in 100% of MRSA, VRE, ESBL, HLAR, and overall, susceptibility to fosfomycin in AmpC producers was extremely high (99%). Norfloxacin and cotrimoxazole were not proved effective as only three isolates were sensitive to norfloxacin, while all Gram-negative isolates were resistant to cotrimoxazole. Pseudomonas species showed 65% and 75% susceptibility to colistin and polymixin B, respectively. CONCLUSION: Fosfomycin has emerged as a promising option, especially in cases involving multi-drug-resistant pathogens in which previous antibiotics have failed to cure the infection.

Prevalence of genotype D in chronic liver disease patients with occult HBV infection in northern region of India.

BACKGROUND: Etiology of nearly 30% cases of chronic viral hepatitis remains undetected. Occult HBV infection (OBI) has emerged as an important clinical entity in this scenario. Apart from prevalence and clinical outcome of OBI patients genotype was determined in northern region of India. MATERIALS AND METHODS: A total of 847 patients with chronic liver disease (CLD) were screened for common viral etiologies and others serological markers of HBV. Amplification of surface, precore and polymerase genes of HBV was performed in patients negative for other etiologies. Genotyping and sequencing of the precore region was performed for OBI cases. RESULTS: Twenty-nine (7.61%) cases of OBI were identifiedof which 9 had chronic liver disease (CHD), 11 liver cirrhosis (LC) and 9 hepatocellular carcinoma (HCC). Majority of OBI cases were detected by amplification of surface gene 26 (89.6%), followed by pre-core gene 12 (41.3%). Their liver functions tests were significantly deranged in comparison to overt HBV cases. IgG anti HBc was present in 8 (27.6%) OBI cases. Mutation was observed in 8 (32%) in pre-core region at nt. 1896 of overt HBV cases. Genotype D was the predominant genotype. IN CONCLUSION: OBI in our study was characterized by predominance of genotype D and more severe clinical and biochemical profile in comparison to overt HBV. IgG anti HBc positivity could be utilized as a marker of OBI. We recommend use of sensitive nested PCR for diagnosis of OBI, amplifying at least surface and precore gene.

Emergence of coryneform bacteria as pathogens in nosocomial surgical site infections in a tertiary care hospital of North India.

PURPOSE: A prospective study was conducted to assess the role of coryneform bacteria in surgical site infections among obstetric and gynecological patients undergoing surgery. MATERIALS AND METHODS: The surgery was graded according to the degree of contamination, and surgical site infections (SSIs) were classified as superficial or deep. Pus samples were collected from SSIs according to rigorous aseptic precautions, and the quality of specimens was assessed by Q-score. A detailed clinical and treatment history was elicited from all patients. The samples were processed using standard protocols. Coryneform bacteria were considered significant pathogens only if they fulfilled rigorous clinical and microbiological criteria. Antibiotic susceptibility testing was performed using the Kirby-Bauer method according to the CLSI guidelines. RESULTS: In total, 127 patients developed SSIs among 882 postoperative patients. Of these, 89 (70.1%) were culture positive: 40 (44.9%) were Gram-positive cocci, 27 (30.3%) were coryneform, and 22 (24.7%) were Gram-negative bacilli. All coryneform-infected patients had fever and post-operative wound dehiscence leading to a prolonged hospital stay. The most commonly isolated organism was Staphylococcus aureus (33.7%), followed by Corynebacterium amycolatum (11.2%), Escherichia coli (8.9%), Citrobacter spp. (7.8%) and coagulase-negative Staphylococci (6.7%). In our study, 45.5% were ESBL producers, 18.2% were Amp C producers, and 40% were MRSA. All the coryneform bacteria were multidrug resistant, and 51.8% of isolates were sensitive to only gatifloxacin and vancomycin. Symptomatic improvement was observed in all coryneform-infected patients after the administration of appropriate therapy. CONCLUSION: Coryneform bacteria appear to be emerging as significant nosocomial surgical site pathogens. The high level of multidrug resistance observed in coryneform bacteria in our study is cause for alarm.

Prevalence and assessment of role of SEN virus in acute and chronic hepatitis in India.

BACKGROUND AND AIM: SEN virus (SENV), is a recently discovered single-stranded DNA virus of Annelloviridae family and is believed may play a role in non A-E hepatitis. We conducted this study to identify the prevalence and clinical association of SENV with acute and chronic hepatitis. METHODS: 135 liver disease patients were studied. Extent of liver damage was assessed using the Model for End Stage Liver Disease (MELD) score. A-E viruses and HIV were detected by enzyme immunoassay. Nested PCR was performed for detection of SENV and its genotypes D and H. RESULTS: 34 cases (25.18%) were positive for SEN virus DNA, a statistically significant finding (p < 0.01) of which 22 (64%) had acute viral hepatitis, 4 (11.76%) had chronic viral hepatitis, 3 (8.82%) fulminant hepatic failure and 5 (14.70%) cirrhosis. Mean AST was 47.85 IU/L, ALT 51.2 IU/L and INR 1.73, mean MELD score was 18.38 (11 to 24). 17.64% had severely deranged MELD score. SENV-D genotype was detected in 13 (38%) and SENV-H in 19 (58%) cases. SENV-H occurred in both acute (53%) and chronic hepatitis (47%). SENV-D was strongly associated with acute hepatitis (85%). Cirrhotic and FHF cases were SENV-H positive. 12 (44.11%) were co-infected with HBV, 5 (14.7%) with TTV, 4(11.76%) with HEV, 2 (5.88%) with HCV and 5 (14.4%) with HIV. CONCLUSION: Significant prevalence of SENV in hepatitis patients was observed. On the basis of clinical findings and abnormal liver function tests, we conclude that SENV appears to be not only hepatotropic but also capable of liver damage. Higher prevalence of SENV-H in cirrhotics may point to its possible role in the development of cirrhosis.

Characterization of clinical strains of MSSA, MRSA and MRSE isolated from skin and soft tissue infections and the antibacterial activity of ZnO nanoparticles.

Staphylococcus aureus, particularly methicillin-resistant S. aureus (MRSA), is an important cause of pyogenic skin and soft tissue infections (SSTIs). MRSA is an important pathogen in the healthcare sector that has neither been eliminated from the hospital nor community environment. In humans, S. aureus causes superficial lesions in the skin and localized abscesses, pyogenic meningitis/encephalitis, osteomyelitis, septic arthritis, invasive endocarditis, pneumonia, urinary tract infections and septicemia. Investigations focused in the search of other alternatives for the treatment of MRSA infections are in progress. Among the range of compounds whose bactericidal activity is being investigated, ZnO nanoparticles (ZnO-NPs) appears most promising new unconventional antibacterial agent that could be helpful to confront this and other drug-resistant bacteria. The aim of present study is to investigate the antibacterial potential of ZnO-NPs against Staphylococcus species isolated from the pus and wounds swab from the patients with skin and soft tissue infections in a tertiary care hospital of north India. ZnO-NPs (≈19.82 nm) synthesized by sol-gel process were characterized using scanning electron microscopy, X-ray diffraction , and Atomic force microscopy. The antibacterial potential was assessed using time-dependent growth inhibition assay, well diffusion test, MIC and MBC test and colony forming units methods. ZnO-NPs inhibited bacterial growth of methicillin-sensitive S. aureus (MSSA), MRSA and methicillin-resistant S. epidermidis (MRSE) strains and were effective bactericidal agents that were not affected by drug-resistant mechanisms of MRSA and MRSE.

Synthesis and characterization of the antibacterial potential of ZnO nanoparticles against extended-spectrum ß-lactamases-producing Escherichia coli and Klebsiella pneumoniae isolated from a tertiary care hospital of North India.

The reemergence of infectious diseases and the continuous development of multidrug resistance among a variety of disease-causing bacteria in clinical setting pose a serious threat to public health worldwide. Extended-spectrum ß-lactamases (ESBLs) that mediate resistance to third-generation cephalosporin are now observed all over the world in all species of Enterobacteriaceae, especially Escherichia coli and Klebsiella pneumoniae. In this work, ZnO nanoparticles (NPs) were synthesized by the sol-gel method and characterized by powder X-ray diffraction, scanning electron microscopy (SEM) and atomic force microscopy (AFM). The image of synthesized ZnO NPs appeared spherical in SEM with a diameter of ≈19 nm and as hexagonal crystal in AFM. Clinical isolates were assessed for ESBL production and shown to be sensitive to ZnO NPs by different methods such as minimal inhibitory concentration (MIC) and minimal bactericidal concentration, time-dependent growth inhibition assay, well diffusion agar methods and estimation of colony forming units (CFU) of bacteria. The lowest MIC value for E. coli and K. pneumoniae was found to be 500 µg/ml. The results showed that ZnO NPs at 1,000 µg/ml completely inhibit the bacterial growth. The antibacterial effect of ZnO nanoparticles was gradual, but time- and concentration-dependent. The maximum inhibition zone at100 µg/ml for E. coli and K. pneumoniae was 22 and 20 mm, respectively. With the increasing ZnO NP loading, there is significant reduction in the numbers of CFU. At the concentration of 1,000 µg/ml, the decline in per cent survival of E. coli and K. pneumoniae was found to be 99.3% and 98.6%, respectively.