Metallo-β-lactamase-producing clinical isolates from patients of a tertiary care hospital

Phenotypic identification of Metallo-ß- lactamase resistance Gram negative bacteria from a clinical specimen in Sidama, Ethiopia

BACKGROUND

Metallo-beta lactamase resistance is one of the carbapenem resistances that worsen the world nowadays. A new variant of carbapenem-resistant has only limited reports from Africa including Ethiopia. This study aimed to determine Metallo -ß- lactamase resistance Gram-negative bacteria in Hawassa University Comprehensive Specialized Hospital January-June 2023.

METHOD

A cross-sectional study was conducted in which consecutive patients infected with Gram-negative bacteria were included in the study. A structured questionnaire was used to collect the data with oriented nurses if the patients/or caregivers gave consent to participate in the study. Clinical specimens are processed based on the standard operating procedure of the Microbiology laboratory and Clinical laboratory standard institute guidelines. Culture and sensitivity testing was used to isolate the bacteria. Gram staining and biochemical tests was used to identify the bacteria to genus and species. Kirby disc diffusion technique was used to determine the susceptibility of antibiotics. Statistical Software for Social Science (SPSS) version 21 is used for data entry and analysis. Descriptive statistics and logistic regression were used to interpret the data. The odds ratio at 95% confidence interval (CI) and p-value < 0.05 were taken as a statistically significant association.

RESULT

Our study included 153 isolates from different specimens, 83 (54.2%) were from male patients and 70 (45.8%) were from females. Klebsiella pneumonia was the predominant 43, followed by Escherichia coli 32, Acinetobacter spp 25, Pseudomonas spp 15, Enterobacter agglomerus 9, Klebsiella ozaenae 6, Enterobacter cloacae 5, Klebsiella oxytoca 4, (Klebsiella rhinoscleromatis, Proteus mirabilis and Morganella morganii) 3, Providencia stuartii 2 and (Citrobacter spp & Proteus vulgaris) 1. The rates of multi, extensive and pan-drug resistance bacteria accounted for 128/153 (83.7%), 77 /153(50.3%), and 26/153 (17.0%), respectively. Carbapenem resistance was 21 (13.7%), of this 7.2% were Enterobacteriaceae, 5.2% were Acetinobacter spp. and 1.3% Pseudomonas spp. Metallo-beta-lactamase was 17 (11.1%), of this, Enterobacteriaceae were 9(5.9%), Acetinobacter spp. 7(4.6%), and Pseudomonas spp. 1(0.7%). There were no variables statistically significantly associated with metallo-beta-lactamase-resistant.

CONCLUSION

Our study revealed that Metallo-beta-lactamase resistance was circulating in the study area. There was a high rate of carbapenem resistance, multi, extensive and pan-drug resistance. Therefore, a measure should be taken to alleviate the emerging threat that leaves the patients without the option of treatment.

Antimicrobial and Diagnostic Stewardship of the Novel β-Lactam/β-Lactamase Inhibitors for Infections Due to Carbapenem-Resistant Enterobacterales Species and Pseudomonas aeruginosa

Carbapenem-resistant Gram-negative bacterial infections are a major public health threat due to the limited therapeutic options available. The introduction of the new β-lactam/β-lactamase inhibitors (BL/BLIs) has, however, altered the treatment options for such pathogens. Thus, four new BL/BLI combinations-namely, ceftazidime/avibactam, meropenem/vaborbactam, imipenem/relebactam, and ceftolozane/tazobactam-have been approved for infections attributed to carbapenem-resistant Enterobacterales species and Pseudomonas aeruginosa. Nevertheless, although these antimicrobials are increasingly being used in place of other drugs such as polymyxins, their optimal clinical use is still challenging. Furthermore, there is evidence that resistance to these agents might be increasing, so urgent measures should be taken to ensure their continued effectiveness. Therefore, clinical laboratories play an important role in the judicious use of these new antimicrobial combinations by detecting and characterizing carbapenem resistance, resolving the presence and type of carbapenemase production, and accurately determining the minimum inhibitor concentrations (MICs) for BL/BLIs. These three targets must be met to ensure optimal BL/BLIs use and prevent unnecessary exposure that could lead to the development of resistance. At the same time, laboratories must ensure that results are interpreted in a timely manner to avoid delays in appropriate treatment that might be detrimental to patient safety. Thus, we herein present an overview of the indications and current applications of the new antimicrobial combinations and explore the diagnostic limitations regarding both carbapenem resistance detection and the interpretation of MIC results. Moreover, we suggest the use of alternative narrower-spectrum antibiotics based on susceptibility testing and present data regarding the effect of synergies between BL/BLIs and other antimicrobials. Finally, in order to address the absence of a standardized approach to using the novel BL/BLIs, we propose a diagnostic and therapeutic algorithm, which can be modified based on local epidemiological criteria. This framework could also be expanded to incorporate other new antimicrobials, such as cefiderocol, or currently unavailable BL/BLIs such as aztreonam/avibactam and cefepime/taniborbactam.

Network meta-analysis of antibiotic resistance patterns in gram-negative bacterial infections: a comparative study of carbapenems, fluoroquinolones, and aminoglycosides

Introduction

Antimicrobial resistance poses a grave global threat, particularly with the emergence of multidrug-resistant gram-negative bacterial infections, which severely limit treatment options. The increasing global threat of antimicrobial resistance demands rigorous investigation, particularly concerning multidrug-resistant gram-negative bacterial infections that present limited therapeutic options. This study employed a network meta-analysis, a powerful tool for comparative effectiveness assessment of diverse antibiotics. The primary aim of this study was to comprehensively evaluate and compare resistance patterns among widely used antibiotic classes, namely carbapenems, fluoroquinolones, and aminoglycosides, for combating gram-negative pathogens.

Methods

We searched PubMed, Web of Sciences, Scopus, Scholarly, Medline, Embase, and Cochrane databases up to August 27, 2023. Studies showing antibiotic resistance in clinical isolates of Enterobacteriaceae, Pseudomonas aeruginosa, and Acinetobacter baumannii exposed to carbapenems, fluoroquinolones, and aminoglycosides were included. This study determined treatment-specific resistance percentages and ranked these treatments based on resistance using a random-effects network meta-analysis technique. To investigate the impact of the study and pathogen features, subgroup and meta-regression analyses were performed. Risk ratios and 95% confidence intervals (CIs) were calculated using a network meta-analysis (NMA) incorporating both direct and indirect evidence. Clinical improvement, cure, microbiological eradication, and death from any cause were the primary outcomes. Nephrotoxicity was a secondary result.

Results

The analysis included 202 publications and 365,782 gram-negative isolates. The NMA included data from 20 studies and 4,835 patients. Carbapenems had the lowest resistance rates throughout the pathogen spectrum, with resistance percentages of 17.1, 22.4, and 33.5% for Enterobacteriaceae, P. aeruginosa, and A. baumannii, respectively. For the same infections, aminoglycosides showed resistance rates of 28.2, 39.1, and 50.2%, respectively. Fluoroquinolones had the highest resistance rates at 43.1, 57.3, and 65.7%, respectively. Unexpectedly, resistance to all three antibiotic classes has increased over time, with multidrug resistance being the most prevalent.

Conclusion

This extensive network meta-analysis provides an overview of the patterns of resistance throughout the world and how they are changing. The most effective choice is still carbapenems, but the increasing resistance highlights the critical need for multimodal therapies to protect antibiotic effectiveness against these powerful gram-negative infections.

Pathogen Burden Among ICU Patients in a Tertiary Care Hospital in Hail Saudi Arabia with Particular Reference to β-Lactamases Profile

Purpose

Ventilator-associated pneumonia (VAP) is associated with a higher mortality risk for critical patients in the intensive care unit (ICU). Several strategies, including using β-lactam antibiotics, have been employed to prevent VAP in the ICU. However, the lack of a gold-standard method for VAP diagnosis and a rise in antibiotic-resistant microorganisms have posed challenges in managing VAP. The present study is designed to identify, characterize, and perform antimicrobial susceptibility of the microorganisms from different clinical types of infections in ICU patients with emphasis on VAP patients to understand the frequency of the latter, among others.

Patients and Methods

A 1-year prospective study was carried out on patients in the ICU unit at a tertiary care hospital, Hail, Saudi Arabia.

Results

A total of 591 clinically suspected hospital-acquired infections (HAI) were investigated, and a total of 163 bacterial isolates were obtained from different clinical specimens with a high proportion of bacteria found associated with VAP (70, 43%), followed by CAUTI (39, 24%), CLABSI (25, 15%), and SSI (14, 8.6%). Klebsiella pneumoniae was the most common isolate 39 (24%), followed by Acinetobacter baumannii 35 (21.5%), Pseudomonas aeruginosa 25 (15.3%), and Proteus spp 23 (14%). Among the highly prevalent bacterial isolates, extended-spectrum beta-lactamase was predominant 42 (42.4%).

Conclusion

Proper use of antibiotics, continuous monitoring of drug sensitivity patterns, and taking all precautionary measures to prevent beta-lactamase-producing organisms in clinical settings are crucial and significant factors in fending off life-threatening infections for a better outcome.

Beta-Lactamase-Producing Gram-Negative Bacterial Isolates Among the Patients Attending a Tertiary Care Hospital, Kathmandu, Nepal

Over the times, carbapenems have been the choice of drug for treating multidrug-resistant (MDR) and extended spectrum beta-lactamase (ESBL)-producing organisms. The current study aimed at determining the occurrence of metallo beta-lactamase (MBL) and AmpC beta-lactamase (ABL) in gram negative bacteria isolated from clinical samples. A cross-sectional study was conducted amongst the patients visiting Manmohan Memorial Medical College and Teaching Hospital (MMTH), Kathmandu, Nepal from August 2017 to January 2018. A total of 4351 samples including urine, pus, wound swab, endotracheal tip, catheter tip, and blood were collected from the patients and processed by standard conventional microbiological methods. Antibiotic susceptibility testing (AST) of the isolates was performed by Kirby-Bauer disk diffusion method. Double disc synergy test was performed on carbapenem resistant organisms to detect production of MBL and inhibitor-based test was used for the detection of ABL production. Of the 4351 samples, 421 bacterial isolates belonging to 16 different genera were recovered, of which 303 (71.97%) were Gram negative bacilli (GNB). E. coli (189/303) and S. aureus (80/118) were the most prevalent among gram negatives and gram positives, respectively. Bacterial incidence was found significantly associated with gender, specimen type, and the department where the patients were enrolled. Colistin-sulfate and polymycin-B were the most effective drug against GNB, whereas imipenem against gram positives. Prevalence of MDR and methicillin-resistant S. aureus (MRSA) was 35.15% and 60%, respectively. The prevalence of MBL and ABL-producing isolate was 11(3.6%) and 13(4.3%), respectively. Pseudomonas aeruginosa (5/11) and E. coli (9/13) were the major MBL and ABL producers, respectively. MBL and ABL production was found to be significantly associated with the age of the patient and the specimen type. A regular antibiotic surveillance activity with screening for MBL and ABL-producing bacterial isolates in the hospital settings to curb the incidence and transmission of such difficult-to-treat pathogens.

Identification and characterization of a novel metallo β-lactamase, SZM-1, in Shenzhen Bay, South China

Metallo β-Lactamases (MBLs) degrade most clinical β-lactam antibiotics, especially Carbapenem, posing a huge threat to global health. Studies on environmental MBLs are important for risk assessment of the MBLs transmission among connected habitats, and between environment and human. Here, we described a novel metallo β-Lactamases, named SZM-1 (Shenzhen metallo-β-lactamase), from an Arenimonas metagenome-assembled genome recovered from the river sediment in the Shenzhen Bay area, south China. Phylogenetic analysis, primary sequence comparison, structural modeling suggested that the SZM-1 belongs to B1 MBL family, likely harboring a typical di-zinc catalytic center. Furthermore, the gene encoding the MBLs was cloned into Escherichia coli TOP10 for Carba NP test and antimicrobial susceptibility test. The results indicated that the SZM-1 had carbapenemase activity, and conferred the carrier to increased resistance toward carbapenems. Taken together, our results raise alarms about the emergence and spread of the SZM-1, and suggest further surveillance, especially in hospital settings and clinical isolates, to determine whether bla_SZM–1 is a mobilizable antibiotic resistance.

Prevalence and Molecular Characterization of Metallo β-Lactamase Producing Gram-Negative Pathogens Causing Eye Infections

Purpose:

Metallo β-lactamases (MβL) production is a worldwide problem, particularly in gram-negative bacteria. As scanty data is available on the prevalence of MBL, the present study is being undertaken to determine the prevalence, antibacterial sensitivity patterns, and molecular characterization of MβL associated resistant genes in gram-negative bacteria isolated from ocular infections.

Material and Methods

At a tertiary eye care center in south India, 359 gram-negative pathogens, 200 isolates from eye infections, and 159 isolates from normal flora of the eye were studied. A gold standard microbiology method was used to identify the isolates. An antibiotic double disc synergy test and a combination disc test were used to detect MβL production. Multiplex PCR was used to investigate the molecular characteristics of the MβL encoding genes blaVIM, blaIMP, and blaNDM.

Results

Of the 359 gram-negative bacterial pathogens, Pseudomonas aeruginosa 108 (30.1%) and Enterobacter agglomerans 46 (12.8%) were commonly isolated. High prevalence of P. aeruginosa 81% (17 strains) was detected as an MβL producer and it shows 100% resistance to 2nd and 3rd generation cephalosporins and meropenem. Multiplex PCR detected only the blaVIM gene in 56 (28%) of various eye infections and 27 (17%) of normal flora of the gram-negative bacteria (GNB). The blaVIM gene is detected predominantly in 51.8% of keratitis and 21.4% of postoperative endophthalmitis. High prevalence of the gene was detected in P. aeruginosa 42.9% (24 of 56) and Alcaligens denitrificans 10.7% (6 of 56) from eye infections. Whereas, in the control group, P. aeruginosa and E. coli each had 14.8% (4 of 27) that were shown positive.

Conclusion

The emerging MβLs mediated resistance among P. aeruginosa is a challenging task for ophthalmologists, especially in patients with endophthalmitis and bacterial keratitis. This local knowledge will aid in advising appropriate antibiotic use and avoiding unnecessary antibiotic prescriptions, which are highly warranted.

Identification of extended spectrum beta lactamases, AmpC and carbapenemase production among isolates of Escherichia coli in North Indian tertiary care centre

Introduction:

Identification of Extended spectrum beta lactamases (ESBL), AmpC production and carbapenemase production among isolates of Escherichia coli, helps clinician to rationalize the choice of antibiotics. However, there is a lack of simple and effective method for simultaneous identification of these beta lactamases.

Aim:

To determine the concurrent production of beta lactamases using twelve disc method on E. coli isolates.

Materials and Methods:

A total of 200 multidrug resistant E. coli were screened using twelve disc method. The isolates of ESBL were confirmed by ceftazidime/clavulanic acid and cefotaxime/clavulanic acid method. Metallo-beta-lactamases (MBL) were confirmed by imipenem EDTA combined disc method.

Results:

Among the 200 isolates, 42.5% were ESBL producers, 9% were MBL and 6.5% were Klebsiella pneumoniae carbapenemase (KPC) and AmpC each respectively. Coproduction was seen in 54 (27%). A significant difference in sensitivity was seen in cefuroxime, aztreonam, cefoxitin and ceftriaxone among inpatient and outpatients.

Conclusion:

The present study highlights burden of ESBL, AmpC, KPC and MBL along with their coproduction in a tertiary care hospital. In-house antibiotic policy, infection control and epidemiological surveys will help us in controlling these resistant bugs. We believe, the twelve disc method is a simple, inexpensive screening method for beta lactamase production.

Antibiotic resistance and sensitivity pattern of Metallo-β-Lactamase Producing Gram-Negative Bacilli in ventilator-associated pneumonia in the intensive care unit of a public medical school hospital in Bangladesh

BACKGROUND

Ventilator-associated pneumonia (VAP) is the most common nosocomial infection in intensive care units (ICU), accounting for 25% of all ICU infections. Antimicrobial resistance is increasing and becoming a significant health problem worldwide, increasing hospital length of stay, mortality and costs. Identifying antibiotic resistance patterns in VAP is important as this can cause outbreaks in ICUs. To date, there have been limited studies assessing this in Bangladesh. Consequently, the primary objective of this research was to study the species of bacterial growth and to determine the antibiotic resistance patterns of Metallo-β-Lactamase (MBL) producing gram-negative bacilli among ICU patients with VAP in a public medical school hospital, Bangladesh. In addition, identify the factors associated with a positive culture to provide future guidance.

METHOD

Cross-sectional study performed in the Chattogram Medical College Hospital, Bangladesh. Mueller Hinton agar plates were used for antibiotic sensitivity testing by the Kirby-Buer disc diffusion test.

RESULTS

Among 105 clinically suspected VAP cases, qualitative cultures were positive in 95 (90%) of them. The most common bacteria identified were Acinetobacter spp. (43.2%), Klebsiella spp. (20%) and Pseudomonas spp. (18.9%). A positive culture was not associated with patients' age or gender. Among 41 isolated Acinetobacter spp., 38 (92.7%) were resistant to gentamicin followed by 36 (87.8%) to ceftriaxone. Among 24 isolated Klebsiella spp., 22 (83.3%) were resistant to ceftriaxone. Among 18 isolated Pseudomonas spp., 16 (88.8%) were resistant to ciprofloxacin, and 13 (72.2%) were resistant to ceftriaxone. Among nine isolated E. coli, all were resistant to ceftriaxone and ciprofloxacin. All four Proteus spp. (100%) isolated were resistant to ciprofloxacin. Additionally, phenotype MBL producing was 65.22% and genotype was 45.65% among imipenem resistant pathogens. Imipenem resistant pathogens were sensitive to amoxyclav, amikacin¸ azithromycin, ceftazidime, ceftriaxone, colistin and gentamycin.

CONCLUSION

A positive culture was detected in 90% of VAP patients, but it was not associated with the patients' age and gender. The most common bacteria identified were Acinetobacter spp., Klebsiella spp. and Pseudomonas spp., where the majority of these were resistant to ceftriaxone. The results are being used to provide future guidance on the empiric management of VAP in this hospital.

Plasmid Profiling and Occurrence of β-Lactamase Enzymes in Multidrug-Resistant Uropathogenic Escherichia coli in Kathmandu, Nepal

INTRODUCTION

Extended-spectrum β-lactamases (ESBL) among Gram-negative bacteria, predominantly Escherichia coli (E. coli), in Nepal, have been rising. The main objectives of this study were to determine the prevalence of uropathogenic E. coli, antibiotic resistance, ESBLs, ABLs (AmpC type β-lactamases), MBLs (metallo-β-lactamases) and KPCs (Klebsiella pneumoniae carbapenemases) and their correlation with plasmid profiling patterns among patients with urinary tract infections in a tertiary hospital in Kathmandu, Nepal.

METHODS

The mid-stream urine samples collected from patients were inoculated in cystine-lactose-electrolyte-deficient (CLED) agar plates. E. coli producing ESBLs, ABLs, MBLs/KPC were identified phenotypically using standard microbiological methods. Plasmids were extracted by alkaline lysis method from E. coli isolates and profiled using agarose gel electrophoresis.

RESULTS

Out of the total 2661 urine samples, E. coli were isolated in 64.34% (507/788), among which 170 (33.53%) were multidrug-resistant (MDR) isolates. All MDR isolates were resistant to amoxicillin and third-generation cephalosporins but were highly sensitive to imipenem (94.12%, 160/170), amikacin (92.94%, 158/170) and nitrofurantoin (86.47%, 147/170). Among 170 MDR isolates, 78.2% (133/170) were ESBLs, 46.3% (50/170) were AmpC, 11.2% (19/170) were MBL and 0.6% (1/170) were KPC producers. Coproduction of β-lactamases was detected in 24.12% (41/170) of isolates. E. coli isolates showed one plasmid (>33.5 kb), which was present in all the isolates. Overall, 44 different plasmid profile groups were identified based on molecular weight and number of plasmids. β-Lactamase producers were relatively resistant to the higher number of antibiotics tested (≤10) than non-producers (≤8), and the number of plasmids were higher in β-lactamase producers (≤7) than those in non-producers (≤5).

CONCLUSION

The higher prevalence of the ESBLs, AmpCs, KPCs and MBLs along with their coproduction in E. coli isolates highlights the importance of routine surveillance of ESBLs, AmpCs, KPCs and MBLs in microbiology laboratories using various phenotypic methods.

Approach to Carbapenemase Detection in Klebsiella pneumoniae in Routine Diagnostic Laboratories

INTRODUCTION

Resistance to Carbapenems in Klebsiella may be due to Carbapenem hydrolysing enzymes. Accurate detection of carbapenemase must be done for patient treatment and epidemiological purposes.

AIM

To detect carbapenemase production by performing Modified Hodge Test (MHT), Combined Disk Test (CDT) for Metallo-β-Lactamases (MBL) and PCR for bla_KPC gene, to evaluate the performance of MHT using MacConkey Agar (MCA) and to access the value of MHT for carbapenemase detection.

MATERIAL AND METHODS

Using a prospective laboratory study design, 153 Extended Spectrum Beta-Lactamases (ESBL) producing Klebsiella pneumoniae from clinical samples of patients admitted in the Kasturba Medical College were collected from January 2014 to December 2015. Isolates resistant to carbapenems by disk diffusion were subjected to MHT on MCA and Mueller Hinton agar (MHA). All isolates were tested for (MBL) production by Imipenem and Imipenem-EDTA CDT and subjected to PCR for the presence of bla_KPC gene.

RESULTS

Out of 153 isolates, 54 were resistant to one of the carbapenems. Among these, 13 were positive for MHT on MHA, while 23 were positive by MHT on MCA. Number of MBL producers was 23 (42.5%), while bla_KPC was detected in 2 out of the 54 isolates.

CONCLUSION

Though detection of drug resistance gene remains the method of choice, it can be performed only in centers with adequate resources. Hence, for most laboratories in resource poor countries, the MHT performed on MCA with concomitant CDT for MBL detection seem to be a better option for detection of Carbapenem resistance.

Antibiotic prescribing in medical intensive care units--a comparison between two private sector hospitals in Central India

BACKGROUND

Inappropriate antibiotic prescribing, common in India, contributes to increased risk for development of bacterial resistance. Patients admitted to intensive care units (ICUs) are often prescribed antibiotics. Paucity of local data on antibiotic prescribing hinders development of appropriate interventions. The aim of the study was to describe and compare antibiotic prescribing in medical ICUs (MICUs) at two private sector hospitals, one teaching (TH) and one non-teaching (NTH) in Ujjain, India.

METHODS

The study was conducted prospectively for 3 years at MICUs of both hospitals. Patients were compared for demographic variables and diagnosis, prescribed antibiotics, generic name prescribing, and route of administration. Adherence to the World Health Organization list of essential medicines (WHOLEM) and the National List of Essential Medicines of India (NLEMI) was analyzed.

RESULTS

In total, 4843 of 6141 patients admitted to the MICUs stayed at least one night. More than 70% were prescribed antibiotics. Generic name prescribing was more common at the TH than at the NTH. Prescriptions at the TH had higher compliance to WHOLEM and NLEMI compared with that at the NTH (p < 0.001). Of the 1371 patients at the TH, 189 (14%) and of 3472 at the NTH, 400 (12%) patients were diagnosed with infections. More than 75% of patients at both hospitals had no infection-associated diagnoses.

CONCLUSIONS

Antibiotic prescribing was common at both hospitals. The antibiotic prescriptions at the TH had higher compliance to WHOLEM and NLEMI. However, there is a need to develop appropriate interventions to improve antibiotic prescribing at both hospitals.

Incidence of metallo-beta-lactamase producing clinical isolates of Escherichia coli and Klebsiella pneumoniae in central Nepal

Background

The increasing and rapid spread of metallo-beta-lactamase (MBL) producing Enterobacteriaceae, particularly Escherichia coli and Klebsiella pneumoniae represents an emerging public health threat. However, limited data is available on MBL production in clinical isolates of E. coli and K. pneumoniae from Nepal. We have therefore undertaken this study to ascertain the incidence of MBL production in clinical isolates of E. coli and K. pneumoniae at a tertiary care teaching hospital in central Nepal.

Methods

A total of 401 consecutive, non-duplicate isolates of E. coli (n = 216) and K. pneumoniae (n = 185) were recovered from various clinical samples between July and December, 2012. These isolates were screened for the detection of carbapenemase production on the basis of their reduced susceptibility to meropenem or ertapenem by the disc diffusion method. The screened isolates were further phenotypically studied for carbapenemase production by modified Hodge test (MHT). MBL production was detected by performing combined disc test by using imipenem discs with and without ethylenediaminetetraacetic acid (EDTA), which chelates zinc required for MBL activity.

Results

Out of 216 E. coli isolates, a total of 41 isolates (18.98%) and out of 185 K. pneumoniae isolates, a total of 39 isolates (21.08%) were suspected to be carbapenemase- producers on the basis of their reduced susceptibility to meropenem or ertapenem. Interestingly, all the initially suspected isolates of E. coli and K. pneumoniae for carbapenemase production were found to be positive in both MHT and combined disc test. However, few weakly positive reactions were observed in MHT. All the MBL producing isolates were multidrug-resistant (MDR). In addition, 75.60% E. coli and 71.79% of K. pneumoniae isolates producing MBL were found to be “pandrug- resistant”.

Conclusions

Our findings showed MBL production in a considerable number of E. coli and K. pneumoniae isolates with MDR and pandrug-resistant phenotypes. Combined disc method can provide a sensible choice for phenotypic detection of MBL production in clinical microbiology laboratories as detection of MBL in bacterial isolates is indispensable for establishing the effective antibiotic policies and infection control strategies in the hospital setting.

The Beta Lactam Antibiotics as an Empirical Therapy in a Developing Country: An Update on Their Current Status and Recommendations to Counter the Resistance against Them

In a developing country like India, where the patients have to bear the cost of their healthcare, the microbiological culture and the sensitivity testing of each and every infection is not feasible. Moreover, there are lacunae in the data storage, management and the sharing of knowledge with respect to the microorganisms which are prevalent in the local geographical area and with respect to the antibiotics which are effective against them. Thus, an empirical therapy for treating infections is imperative in such a setting. The beta lactam antibiotics have been widely used for the empirical treatment of infections since the the discovery of penicillin. Many generations of beta lactams have been launched with, the claims of a higher sensitivity and less resistance, but their sensitivity has drastically decreased over time. Thus, the preference for beta lactams, especially the cephalosporins, as an empirical therapy, among the prescribers was justified initially, but the current sensitivity patterns do not support their empirical use in hospital and community acquired infections. There is a need for increasing the awareness and the attitudinal change among the prescribers, screening of the antibiotic prescriptions, the strict implementation of antibiotic policies in hospital settings, restricting the hospital supplies and avoiding the prescriptions of beta lactams, a regular census of the local sensitivity patterns to formulate and update the antibiotic policies, upgradation of the laboratory facilities for a better and faster detection of the isolates, proper collection, analyses and sharing of the data and the encouragement of the research and development of newer antibiotics with novel mechanisms of action.

ESBL, MBL and Ampc β Lactamases Producing Superbugs - Havoc in the Intensive Care Units of Punjab India

BACKGROUND

An alarming rise in the rates of the antibiotic resistance has now become a serious and an increasingly common public health concern, with severe implications, especially in the intensive care units. A variety of β-lactamases which include ESBLs, AmpC β-lactamases and metallo-βlactamases, have emerged as the most worrisome mechanism of resistance among the gram negative bacteria, which pose a therapeutic challenge to the health care settings.

MATERIALS AND METHODS

The present study was aimed at knowing the prevalence of various β-lactamases in the gram negative isolates which were obtained from ICU patients. A total 273 gram negative isolates from 913 clinical samples which were received over a period of one year were processed for their identification and their antimicrobial susceptibility pattern was determined. They were then screened for the β-lactamase production.

RESULTS

Among the 273 isolates, the β-lactamase production was observed in 193 strains. 96 (35.16%) strains were ESBL producers, followed by 30 (10.98%) metallo β- lactamase (MBL) producers and 15(5.4%) AmpC producers. The major ESBL and AmpC producer was Escherichia coli, while Klebsiella pneumonia was the predominant MBL producer. The co production of the ESBL/MBL/ AmpC β- lactamases was observed in 52 (19.04%) strains and it was more common in Escherichia coli. A multidrug resistance to the fluoroquinolones and the aminoglycosides was also observed in the β- lactamase producing organisms.

CONCLUSION

The high prevalence of the β- lactamases in the ICU isolates emphasizes the need for a continuous surveillance in the ICUs to detect the resistant strains, strict guidelines for the antibiotic therapy and the implementation of infection control measures to reduce the increasing burden of antibiotic resistance.