β -Lactamase-Producing Multidrug-Resistant Bacterial Pathogens from Tracheal Aspirates of Intensive Care Unit Patients at National Institute of Neurological and Allied Sciences, Nepal

Inhibition and Reduction of Biofilm Production along with Their Antibiogram Pattern among Gram-Negative Clinical Isolates

Background

Bacterial biofilm is a significant virulence factor threatening patients, leading to chronic infections and economic burdens. Therefore, it is crucial to identify biofilm production, its inhibition, and reduction. In this study, we investigated biofilm production among Gram-negative isolates and assessed the inhibitory and reduction potential of ethylene diamine tetra acetic acid (EDTA) and dimethyl sulfoxide (DMSO) towards them. In addition, we studied the antimicrobial resistance pattern of the Gram-negative isolates.

Methods

Bacterial isolation and identification was done using standard microbiological techniques, following the Clinical and Laboratory Standards Institute (CLSI) guideline, 28th edition. The Kirby-Bauer disk diffusion method was used to determine the antibiotic susceptibility pattern of the isolates, and β-lactamase production was tested via the combination disk method. Biofilm formation was detected through the tissue culture plate (TCP) method. Different concentrations of EDTA and DMSO were used to determine their inhibitory and reduction properties against the biofilm. Both inhibition and reduction by the various concentrations of EDTA and DMSO were analyzed using paired t-tests.

Results

Among the 110 clinical isolates, 61.8% (68) were found to be multidrug resistant (MDR). 30% (33/110) of the isolates were extended-spectrum β-lactamase (ESBL) producers, 14.5% (16/110) were metallo-β-lactamase (MBL), and 8% (9/110) were Klebsiella pneumoniae carbapenemase (KPC) producers. Biofilm formation was detected in 35.4% of the isolates. Biofilm-producing organisms showed the highest resistance to antibiotics such as cephalosporins, chloramphenicol, gentamicin, and carbapenem. The inhibition and reduction of biofilm were significantly lower (p < 0.05) for 1 mM of EDTA and 2% of DMSO.

Conclusion

Isolates forming biofilm had a higher resistance rate and β-lactamase production compared to biofilm nonproducers. EDTA and DMSO were found to be potential antibiofilm agents. Hence, EDTA and DMSO might be an effective antibiofilm agent to control biofilm-associated infections.

Systematic Review and Meta-analysis on Extended-Spectrum β-lactamases Producing Klebsiella pneumoniae in Nepal

Objective

This systematic review and meta-analysis aimed to assess the pool estimates of extended-spectrum β-lactamases producing K. pneumoniae (ESBL-KP) and study their drug resistance profile by evaluating the studies from Nepal.

Methods

A literature search was carried out in PubMed, Google Scholar, and NepJOL to screen all articles on ESBL-KP published between 2011 and 2021 from Nepal. This review was conducted following Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines. Relevant data were extracted, and R language 4.2.0 software was used for statistical analysis.

Results

The pooled prevalence of K. pneumoniae was 5%, while the pooled prevalence of ESBL and multidrug resistance (MDR) in K. pneumoniae were 23% and 55%, respectively. Imipenem was the drug of choice (in vitro) against ESBL-KP infection.

Conclusion

Our analyses showed a high prevalence of ESBL-KP and their high resistance toward commonly used drugs. This study highlights the need for the development of new antibiotics for the management of ESBL-KP infections.

Pseudomonas aeruginosa Isolates among Clinical Samples showing Growth in a Tertiary Care Centre: A Descriptive Cross-sectional Study

Introduction

Carbapenems resistance due to metallo-beta-lactamase production in Pseudomonas aeruginosa is a major concern which is increasing globally resulting in limited therapeutic choices. This study aimed to find out the prevalence of Pseudomonas aeruginosa isolates among clinical samples showing growth of a tertiary care centre.

Methods

A descriptive cross-sectional study was conducted on various clinical samples which showed growth in the Department of Microbiology of a tertiary care centre between 1 September 2020 to 28 February 2021 after receiving ethical approval from the Institutional Review Committee (Reference number: 03-G/020). Convenience sampling was done. All timely received clinical specimens were inoculated and incubated at 37°C for 48 hours and identified by standard microbiological techniques. Point estimate and 95% Confidence Interval were calculated.

Results

Among 1049 clinical samples showing growth, 68 (6.48%) (4.99-7.97, 95% Confidence Interval) Pseudomonas aeruginosa were isolated. Among them, 6 (8.82%) were found to be metallo-beta-lactamase positive.

Conclusions

The prevalence of Pseudomonas aeruginosa was similar to the studies done in similar settings. As metallo-beta-lactamase production was detected among isolated species which can be spread very rapidly and may develop a problematic scenario in treatment procedures, regular surveillance along with judicious use of carbapenems should precede.

Keywords

beta-lactamase; multidrug resistant; Pseudomonas aeruginosa.

Biofilm Formation and Phenotypic Detection of ESBL, MBL, KPC and AmpC Enzymes and Their Coexistence in Klebsiella spp. Isolated at the National Reference Laboratory, Kathmandu, Nepal

Klebsiella spp. are associated with several nosocomial and opportunistic infections. Increasing antimicrobial resistance of Klebsiella species is aggravated by a number of intrinsic and extrinsic factors. The main aim of this study is to determine antimicrobial resistance due to production of β-lactamase enzymes, extended spectrum beta-lactamase (ESBL), metallo-beta-lactamase (MBL) and AmpC and Klebsiella pneumoniae carbapenemase (KPC) and biofilm formation in Klebsiella isolates. A total of 2197 non-duplicate specimens of urine, sputum and pus were obtained from the National Public Health Laboratory (NPHL), Kathmandu, Nepal, between February and August 2019. Klebsiella species were isolated, identified and screened for antimicrobial susceptibility testing with the disk diffusion method. Phenotypic detection of ESBL, MBL, KPC and AmpC production was observed and biofilm production was detected by the microtiter plate method. Out of a total of 2197 clinical specimens, bacterial growth was detected in 8% (175/2197) of the specimens. Of the total isolates, 86.3% (151/175) were Gram-negative bacteria and 37.7% (57/151) were Klebsiella spp. Of the total Klebsiella spp., 56% (32/57) were multi drug resistant (MDR), 16% (9/57) were ESBL, 26% (15/57) were MBL, 4% (2/57) were KPC (class A carbapenemase), 16% (9/57) were AmpC producers and 95% (54/57) were biofilm producers. Gentamicin was the most effective antibiotic, followed by cotrimoxazole, as 68% (39/57) and 47% (27/57) of the Klebsiella isolates were susceptible towards these drugs, respectively. The study results show evidence of β-lactamase production, high prevalence of MDR and biofilm producing Klebsiella species. Integrating the test parameters for phenotypic confirmation of ESBL, MBL, AmpC β lactamase and KPC in routine diagnostic procedures can help in the early detection and management of these resistant strains.

Biofilm Formation by Pathogens Causing Ventilator-Associated Pneumonia at Intensive Care Units in a Tertiary Care Hospital: An Armor for Refuge

Background

Emerging threat of drug resistance among pathogens causing ventilator-associated pneumonia (VAP) has resulted in higher hospital costs, longer hospital stays, and increased hospital mortality. Biofilms in the endotracheal tube of ventilated patients act as protective shield from host immunity. They induce chronic and recurrent infections that defy common antibiotics. This study intended to determine the biofilm produced by pathogens causing VAP and their relation with drug resistance.

Methods

Bronchoalveolar lavage and deep tracheal aspirates (n = 70) were obtained from the patients mechanically ventilated for more than 48 hours in the intensive care units of Tribhuvan University Teaching Hospital, Kathmandu, and processed according to the protocol of the American Society for Microbiology (ASM). Antibiotic susceptibility testing was done following Clinical and Laboratory Standards Institute (CLSI) 2017 guidelines. Biofilm formation was determined using the microtiter plate method described by Christensen and modified by Stepanovoic et al.

Results

Significant microbial growth was seen in 78.6% of the total samples with 52.7% monomicrobial, 45.5% polymicrobial, and 1.8% fungal infection. Among the 71 isolates obtained, bulk was gram-negative (n = 64, 90.1%). Pseudomonas aeruginosa (31.0%) was the predominant isolate followed by Acinetobacter calcoaceticus baumannii complex (16.9%), Klebsiella pneumoniae (16.9%), Citrobacter freundii (15.5%), Staphylococcus aureus (7.0%), Escherichia coli (5.6%), Citrobacter koseri (2.8%), Enterococcus faecalis (1.4%), Burkholderia cepacia complex (1.4%), and Candida albicans (1.4%). Of the total isolates, 56.3% were biofilm producers. Multidrug-resistant (MDR) organisms, extended-spectrum β-lactamase (ESBL), and metallo-β-lactamase (MBL) producers were preeminent among the biofilm producers. The highest producer of biofilm was P. aeruginosa (19.7%). Among gram-negative biofilm producers, 42.2% were MDR, 21.9% were ESBL producers, and 7.8% were MBL producers.

Conclusion

Gram-negative nonfermenter bacteria account for the bulk of nosocomial pneumonia. MDR, ESBL, and MBL production was preponderant among the biofilm producers. The rampant spread of drug resistance among biofilm producers is summoning novel interventions to combat multidrug resistance.

A high prevalence of multi-drug resistant Gram-negative bacilli in a Nepali tertiary care hospital and associated widespread distribution of Extended-Spectrum Beta-Lactamase (ESBL) and carbapenemase-encoding genes

BACKGROUND

Multi-drug resistance (MDR) and extensive-drug resistance (XDR) associated with extended-spectrum beta-lactamases (ESBLs) and carbapenemases in Gram-negative bacteria are global public health concerns. Data on circulating antimicrobial resistance (AMR) genes in Gram-negative bacteria and their correlation with MDR and ESBL phenotypes from Nepal is scarce.

METHODS

A retrospective study was performed investigating the distribution of ESBL and carbapenemase genes and their potential association with ESBL and MDR phenotypes in E. coli, Klebsiella spp., Enterobacter spp. and Acinetobacter spp. isolated in a major tertiary hospital in Kathmandu, Nepal, between 2012 and 2018.

RESULTS

During this period, the hospital isolated 719 E. coli, 532 Klebsiella spp., 520 Enterobacter spp. and 382 Acinetobacter spp.; 1955/2153 (90.1%) of isolates were MDR and half (1080/2153) were ESBL producers. Upon PCR amplification, bla_TEM (1281/1771; 72%), bla_CTXM-1 (930/1771; 53%) and bla_CTXM-8 (419/1771; 24%) were the most prevalent ESBL genes in the enteric bacilli. Bla_OXA and bla_OXA-51 were the most common bla_OXA family genes in the enteric bacilli (918/1771; 25%) and Acinetobacter spp. (218/382; 57%) respectively. Sixteen percent (342/2153) of all isolates and 20% (357/1771) of enteric bacilli harboured bla_NDM-1 and bla_KPC carbapenemase genes respectively. Of enteric bacilli, Enterobacter spp. was the most frequently positive for bla_KPC gene (201/337; 60%). The presence of each bla_CTX-M and bla_OXA were significantly associated with non-susceptibility to third generation cephalosporins (OR 14.7, p < 0.001 and OR 2.3, p < 0.05, respectively).The presence of each bla_TEM, bla_CTXM and bla_OXA family genes were significantly associated with ESBL positivity (OR 2.96, p < 0.001; OR 14.2, p < 0.001 and OR 1.3, p < 0.05 respectively) and being MDR (OR 1.96, p < 0.001; OR 5.9, p < 0.001 and OR 2.3, p < 0.001 respectively).

CONCLUSIONS

This study documents an alarming level of AMR with high prevalence of MDR ESBL- and carbapenemase-positive ESKAPE microorganisms in our clinical setting. These data suggest a scenario where the clinical management of infected patients is increasingly difficult and requires the use of last-resort antimicrobials, which in turn is likely to intensify the magnitude of global AMR crisis.

Detection of bla NDM-1 Encoding Imepenemase among the Imipenem-Resistant Gram-Negative Bacilli Isolated from Various Clinical Samples at a Tertiary Care Hospital of Eastern Nepal: A Descriptive Cross-Sectional Study

Background

Carbapenem resistance among Gram-negative isolates caused by the production of the metallo-β-lactamase (MBL) enzyme is being increasingly reported worldwide. One of the newly emerged metallo-β-lactamases is New Delhi metallo-β-lactamase. Data regarding its occurrence in hospital setting and percentage prevalence among different Gram-negative bacterial isolates are lacking in our part. This study has been undertaken for determining the presence of the bla NDM-1 gene among the clinical isolates of imipenem-resistant Gram-negative bacteria in a tertiary care center in Dharan, Nepal.

Methods

A total of 75 imipenem-resistant Gram-negative isolates were studied. These were screened for metallo-β-lactamase (MBL) production by phenotypic assays such as double-disc synergy test (DDST) and combined disc diffusion test (CDDT). PCR was performed for the molecular detection of gene NDM-1. Ten-disc method was performed to detect the presence of ESBL, AmpC, carbapenamase, and K1 β-lactamase production.

Results

Using the molecular method, bla NDM-1 was detected in 36% of the isolates. Phenotypically, double-disc synergy test (DDST) and combined disc diffusion test (CDST) detected MBL production in 38.7% and 37.3% of the isolates, respectively. Ten-disc method detected ESBL in 26.6% of the isolates, but none of the isolates was found to be AmpC, carbapenamase, and K1 β-lactamase producers.

Conclusion

A high percentage of the NDM-1 producer was noted among imipenem-resistant GNB. Apart from performing only antimicrobial sensitivity test, phenotypic and molecular screening should be employed to find out the actual number of metallo-β-lactamase producers and the existence of the resistance gene.

Prevalence of Common Nosocomial Infections and Evaluation of Antibiotic Resistance Patterns in Patients with Secondary Infections in Hamadan, Iran

Introduction

The prevalence of nosocomial infections in patients hospitalized to three hospitals of Shahid Beheshti, Farshchian, and Be’ saat in Hamadan was investigated for 2 years (2018 to 2020).

Materials and Methods

The samples were cultured and characterized using morphological and diagnostic biochemical tests. The analysis of the frequency of the isolates and their antibiotic resistance were calculated using SPSS (version 22) at a significant level of P-value < 0.05.

Results

Bacterial isolates were collected from the 1194 clinical specimens, of which 1394 were isolated from urine, 16 from CSF, and 588 from tracheal aspiration. Also, 654 (54.8%) isolates were obtained from females and 540 (45.2%) from males with the age range 15–73 years (P> 0.05). The results showed that 22.1% were gram-positive and 77.9% were gram-negative. In our study, the frequency of Klebsiella pneumoniae bacteria was higher than in some studies, and this indicates the genetic changes and resistance of this bacterium to many antibiotics.

Conclusion

To prevent further spread of resistance, increase the effectiveness of antibiotics and prevent multidrug resistance, it is essential to establish a precise schedule for the use of antibiotics and assess the resistance pattern periodically in each region based on the antibiotic resistance pattern.

The spectrum of bacteria and mechanisms of resistance identified from the casualties treated in the Israeli field hospital after the earthquake in Nepal, 2015: A retrospective analysis

BACKGROUND

On the April 25, 2015, a 7.8 magnitude earthquake struck Nepal. Soon-after, the Israel Defense Force (IDF) dispatched a tertiary field-hospital to Kathmandu. The field-hospital was equipped with a clinical laboratory with microbiology capabilities. Limited data exists regarding the spectrum of bacteria isolated from earthquake casualties. We aimed to identify the spectrum of bacteria and their mechanisms of resistance in-order to allow preparedness of antibiotic treatment protocols for future disaster scenarios.

METHODS

- The field-laboratory phenotypically processed cultures from sterile and non-sterile sites as needed clinically. Later-on, the isolates were brought to Israel for quality control, definite identification and molecular characterization including mechanisms of resistance.

RESULTS

A total of 82 clinical pathogens were isolated from 56 patients; 68% of them were Gram negative bacilli. The most common isolates were Enterobacteriaceae (55%) -36% carried bla-_NDM and 33% produced Extended-spectrum beta-lactamase (ESBL), mostly bla_CTX-M-15. Enterococcus spp were the main Gram positive bacteria isolated (22 isolates), yet, none were vancomycin resistant. The overall level of resistance was 27% MDR and 23% extensively drug resistant (XDR) bacteria.

CONCLUSIONS

- Gram negative bacteria were the predominant organism cultured from the casualties, of them 77% were MDR or XDR. NDM was the most common resistance mechanism. The Antibiotic inventory of a field-hospital should be set to cover a wide and unexpected spectrum of bacteria, including resistant organisms. This report adds important information to the scarce reports of bacterial resistance in Nepal.

Incidence and outcomes of multidrug-resistant gram-negative bacteria infections in intensive care unit from Nepal- a prospective cohort study

Background

Infections caused by multi-drug resistant gram-negative bacterial infections are the principle threats to the critically ill patients of intensive care units. Increasing reports of these infections from the Nepalese intensive care unit underline the clinical importance of these pathogens. However, the impact of these infections on the patient’s clinical outcome has not yet been clearly evaluated. The objective of our study was to determine the incidence and associated clinical outcome of multi-drug resistant gram-negative bacterial infections in intensive care unit from a tertiary care center of Nepal.

Methods

A prospective cohort study was conducted among adult patients admitted in intensive care unit of B. P Koirala Institute of Health Sciences from July to December 2017. Patients infected with multi-drug resistant gram-negative bacteria, non-multi-drug resistant gram-negative bacteria and those without infection were included. Identification of gram-negative bacteria and their antibiotic susceptibility pattern was performed with standard microbiological methods. Demographic, clinical profiles and outcomes (in-hospital-mortality, intensive care unit and hospital length of stay) were documented.

Results

The incidence rate of multi-drug resistant gram-negative bacteria infections was 47 per 100 admitted patients (64/137) with 128 episodes. Acinetobacter species (41%, 52/128) was the commonest followed by Klebsiella pneumoniae (28%, 36/128) and Pseudomonas spp (21%, 27/128). Patients with multi-drug resistant gram-negative bacteria in comparison to non-multi-drug resistant gram-negative bacteria had high healthcare-associated infections (95%, 61/64 versus 20%, 2/10; p = < 0.001). In-hospital-mortality was 38% (24/64), 20% (2/10) and 10% (4/41) in multi-drug resistant, non-multi-drug resistant and uninfected group respectively (p = 0.007). After adjustment for independent risk factors, compared to uninfected patients, the odds ratio (CI) for in-hospital-mortality in multi-drug resistant and non-multi-drug resistant group was (4.7[1.4–15.5], p = 0.01) and 2.60 [0.38–17.8], p = 0.32) respectively. Multi-drug resistant patients also had longer intensive care unit and hospital stay, however, it was statistically insignificant.

Conclusion

The incidence of multi-drug resistant gram-negative bacterial infections was remarkably high in our intensive care unit and showed a significant association with healthcare-associated infections and in-hospital-mortality.

A hospital based surveillance of metallo-beta-lactamase producing gram negative bacteria in Nepal by imipenem-EDTA disk method

BACKGROUND

A rising threat of the rapid spread of acquired metallo-beta-lactamases (MBLs) among major Gram-negative pathogens is a matter of public health concern worldwide. Hence, for a low income nation like Nepal, surveillance data on MBL producing clinical isolates via a cost effective technique is necessary to prevent their dissemination as well as formulation and regulation of antimicrobial stewardship policy.

METHODS

The prospective study was conducted at Nepal Medical College, Kathmandu from May to October, 2014 to assess the prevalence of MBL production among ceftazidime-resistant Gram-negative rods (GNRs) isolates. The samples were processed according to standard microbiological procedure following the Manual of clinical Microbiology. Isolated GNRs were subjected to susceptibility testing against the selected panel of antibiotics by Kirby- Bauer disc diffusion method and interpretation made in conformity with the Clinical and Laboratory Standards Institute (CLSI) guidelines. Ceftazidime-resistant isolates were subjected to the detection of MBL production by imipenem-EDTA combined disc (CD) method.

RESULTS

Among the Gram-negative isolates, 5.80% (21/362) were found to be MBL positive with Acinetobacter spp. showing the highest prevalence i.e. 85.71% (18/21), followed by P. aeruginosa i.e. 14.29% (3/21). None of the other cefazidime resistant gram negative bacteria tested were found to be positive for MBL production with all the positive isolates determined to be Multidrug resistant (MDR) strains.

CONCLUSION

This study demonstrated a higher rate of resistance among P. aeruginosa and Acinetobacter spp. to a wide variety of antibiotic categories with an additional burden of MBL production within them, warranting a need for strict surveillance and rapid detection of MBL production among the GNRs.

High burden of antimicrobial resistance among gram negative bacteria causing healthcare associated infections in a critical care unit of Nepal

Background

Healthcare associated infections (HCAI) and antimicrobial resistance are principal threats to the patients of intensive care units and are the major determining factors for patient outcome. They are associated with increased morbidity, mortality, excess hospitalization and financial costs. The present study is an attempt to investigate the spectrum and antimicrobial resistance of bacterial isolates involved in healthcare associated infections (HCAI) in the patients of a critical care unit at a tertiary care university hospital in Kathmandu, Nepal.

Methods

A laboratory based study was conducted over the period of 15 months (January 2014 to March 2015) among the patients of intensive care unit of Tribhuvan University Teaching Hospital, Kathmandu, Nepal. Clinical specimens from patients with suspected healthcare-associated infection were processed and bacterial isolates were identified with standard microbiological methods. Antimicrobial susceptibilities of the isolated strains were determined according to the CLSI guidelines and β-lactamases (ESBL, AmpC, MBL and KPC) were detected by various phenotypic tests.

Results

One hundred and forty nine clinical specimens received from 135 patients suspected of HCAI (out of 491 patients) were found with significant bacterial growth. Specimens were from patients suspected of hospital-acquired pneumonia (16%, 79/491), bloodstream infections (5.7%, 28/491), surgical site infections (4.7%, 23/491), and urinary tract infections (3.9%, 19/491). Acinetobacter spp., Klebsiella spp., Escherichia coli and Burkholderia cepacia were the leading bacterial pathogens. Extremely high level of drug resistance (95.8%) along with the production of β-lactamases (ESBL; 43.7%, AmpC; 27.5%), MBL; 50.2% and KPC; 4.2%) was observed among Gram negative bacterial isolates.

Conclusion

Healthcare associated infections are very common in our ICU. Gram negative bacterial pathogens are major culprits associated with these infections and there is alarming state of drug resistance among these isolates. Continuous surveillance and establishment of preventive and control measures of healthcare associated infections are urgently needed in our setting.

Emerging Perils of Extended Spectrum β-Lactamase Producing Enterobacteriaceae Clinical Isolates in a Teaching Hospital of Nepal

Introduction. Infections due to extended spectrum β-lactamase producing Enterobacteriaceae are on the rise. They pose serious public health problems due to their resistance to large number of antibiotics. However, little is known about the genotypes of ESBL from Nepal. Therefore, the study presents results of phenotypic and molecular characterization of ESBL producing Escherichia coli and Klebsiella spp. isolated from various clinical specimens in a tertiary care teaching hospital of Nepal. Methods. A total of 172 Enterobacteriaceae clinical isolates recovered from various clinical specimens were analyzed for their antibiotic susceptibility test. Detection of ESBLs was carried out using combination disk test and multiplex PCR for their genotypes (CTX-M, SHV, and TEM). Results. Out of 172 clinical isolates, 70 (40.6%) of them were found ESBL producers. The major source of ESBL producers was urinary tract samples and the highest ESBL production was observed in Escherichia coli (46.5%). Among ESBL genotypes, CTX-M (91.4%) was most predominant, followed by TEM (65.7%) and SHV (11.4%) in both of the isolates. Conclusions. High level of drug resistance and ESBL production was observed among the clinical isolates. There is a need for longitudinal and nationwide surveillance for drug resistance in clinical isolates and antimicrobial stewardship is necessary to guide the appropriate and judicious antibiotic use.

Growing Menace of Antibacterial Resistance in Clinical Isolates of Pseudomonas aeruginosa in Nepal: An Insight of Beta-Lactamase Production

Introduction. Pseudomonas aeruginosa is the most frequently isolated organism as it acts as the opportunistic pathogen and can cause infections in immunosuppressed patients. The production of different types of beta-lactamases renders this organism resistant to many commonly used antimicrobials. Therefore, the aim of this study was to document the antibiotic resistance rate in Pseudomonas aeruginosa isolated from different clinical specimens. Methods. Pseudomonas aeruginosa recovered was identified by standard microbiological methods. Antibiotic susceptibility testing was performed by modified Kirby-Bauer disc diffusion method following Clinical and Laboratory Standard Institute (CLSI) guidelines and all the suspected isolates were tested for the production of ESBLs, MBLs, and AmpC. Results. Out of total (178) isolates, 83.1% were recovered from the inpatient department (IPD). Majority of the isolates mediated resistance towards the beta-lactam antibiotics, while nearly half of the isolates were resistant to ciprofloxacin. Most of the aminoglycosides used showed resistance rate up to 75% but amikacin proved to be better option. No resistance to polymyxin was observed. ESBLs, MBLs, and AmpC mediated resistance was seen in 33.1%, 30.9%, and 15.7% isolates, respectively. Conclusions. Antibiotic resistance rate and beta-lactamase mediated resistance were high. Thus, regular surveillance of drug resistance is of utmost importance.

Presence of metallo-beta-lactamases (MBL), extended-spectrum beta-lactamase (ESBL) & AmpC positive non-fermenting Gram-negative bacilli among Intensive Care Unit patients with special reference to molecular detection of blaCTX-M & blaAmpC genes

BACKGROUND & OBJECTIVES

Non-fermenting Gram-negative bacilli (NFGNB) including Pseudomonas aeruginosa and Acinetobacter baumannii have been implicated in a variety of infections, particularly in the Intensive Care Units (ICUs). This study was aimed to overview the burden of multidrug-resistant NFGNB causing infections in ICU and also to assess the occurrence of extended-spectrum beta-lactamases (ESBLs), AmpC and metallo-beta-lactamases (MBLs) among these isolates.

METHODS

Bacterial culture, identification and antibiotic susceptibility were carried out. ESBLs and AmpC were detected both phenotypically and genotypically. MBL was detected by modified Hodge and imipenem-ethylenediaminetetraacetic acid double-disc synergy test.

RESULTS

NFGNB represented 45 (37%) of total 121 Gram negative isolates. Multidrug resistance was observed in 66.9 per cent and 72.5 per cent isolates of P. aeruginosa and A. baumannii, respectively. Detection by phenotypic methods showed presence of ESBL, AmpC and MBL in 21.4, 51.1 and 21.4 per cent isolates, respectively. When detected genotypically by polymerase chain reaction, ESBL and AmpC were detected in 21.4 and 41.4 per cent of NFGNB isolates, respectively. BlaCTX-M (21.4%) was the most prevalent gene responsible for ESBL production.

INTERPRETATION & CONCLUSIONS

Most of the NFGNB isolated from ICU patients were multidrug-resistant and producers of ESBL, AmpC and MBL. A regular surveillance is required to detect ESBL, AmpC and MBL producers, especially in ICU patients.

Epidemiology of Multidrug Resistant Uropathogenic Escherichia coli in Iran: a Systematic Review and Meta-Analysis

Urinary tract infection (UTI) is one of the most common infections in humans. It is primarily caused by uropathogenic Escherichia coli (UPEC), which has a high multidrug resistance (MDR). In consideration of the prevalence of MDR-UPEC strains, the aims of the present study were to systematically review the published data about the prevalence rate of MDR-UPEC from different parts of Iran and to establish the overall relative frequency (RF) of these strains in Iran. We searched several databases including PubMed, ISI Web of Science, Scopus, Google Scholar, IranMedex, and Iranian Scientific Information Database by using the following keywords: "Escherichia coli", "multidrug resistant", "MDR", "urinary tract infections", "UTI", "uropathogenic". and "Iran". Articles or abstracts that reported the prevalence of MDR-UPEC were included in this review. We found 15 articles suitable for inclusion in this study. A pooled estimation of 10,247 UPEC strains showed that 49.4% (95% confidence interval = 48.0-50.7%) of the stranis were MDR positive. The RF of MDR-UPEC in different studies varied from 10.5% to 79.2% in the Kashan and Hamedan provinces, respectively. According to the results of the present study, the RF of MDR-UPEC in Iran is high. Thus, measures should be taken to keep the emergence and transmission of these strains to a minimum.

Incidence of Multidrug-Resistant Pseudomonas Spp. in ICU Patients with Special Reference to ESBL, AMPC, MBL and Biofilm Production

BACKGROUND

Multidrug-resistant (MDR) Pseudomonas spp. have been reported to be the important cause of ICU infections. The appearance of ESBL, AmpC and MBL genes and their spread among bacterial pathogens is a matter of great concern. Biofilm production also attributes to antimicrobial resistance due to close cell to cell contact that permits bacteria to more effectively transfer plasmids to one another. This study aimed at determining the incidence of ESBL, AmpC, MBL and biofilm producing Pseudomonas spp. in ICU patients.

MATERIAL AND METHODS

The clinical specimens were collected aseptically from 150 ICU patients from February 2012 to October 2013. Identification and antimicrobial susceptibility was performed according to Clinical and Laboratory Standards Institute (CLSI) guidelines. ESBLs and AmpC were detected phenotypically and genotypically. MBL was detected by modified Hodge and imipenem-EDTA double-disk synergy test.

RESULTS

Pseudomonas spp. 35(28%) were the most prevalent pathogen in ICU infections. Multidrug resistance and biofilm production was observed in 80.1% and 60.4% isolates, respectively. Prevalence of ESBL, AmpC and MBL was 22.9%, 42.8% and 14.4%, respectively. The average hospital stay was 25 days and was associated with 20% mortality.

CONCLUSIONS

A regular surveillance is required to detect ESBL, AmpC and MBL producers especially in ICU patients. Carbapenems should be judiciously used to prevent their spread. The effective antibiotics, such as fluoroquinolones and piperacillin-tazobactum should be used after sensitivity testing.

Nosocomial Isolates and Their Drug Resistant Pattern in ICU Patients at National Institute of Neurological and Allied Sciences, Nepal

Multidrug resistant organisms are increasing day by day and the cause is poorly known. This study was carried out from June 2011 to May 2012 at National Institute of Neurological and Allied Sciences Kathmandu, Nepal, with a view to determining drug resistant pathogens along with detection of extended spectrum β-lactamase (ESBL), AmpC β-lactamase (ABL), and metallo-β-lactamase (MBL) producing bacteria causing infection to ICU patients. A standard methodology was used to achieve these objectives as per recommendation of American Society for Microbiology. ESBL was detected by combined disc assay using cefotaxime and cefotaxime clavulanic acid, ABL by inhibitor based method using cefoxitin and phenylboronic acid, and MBL by imipenem-EDTA combined disk method. Two hundred and ninety-four different clinical samples such as tracheal aspirates, urine, pus, swabs, catheter tips, and blood were processed during the study. Most common bacteria were Acinetobacter spp. Of the total 58 Acinetobacter spp., 46 (79%) were MDR, and 27% were positive for ABL and 12% were for MBL. Of the 32 cases of Staphylococcus aureus, 18 (56%) were MDR. Findings of this study warrant routine β-lactamase testing in clinical isolates.

Community acquired multi-drug resistant clinical isolates of Escherichia coli in a tertiary care center of Nepal

Background

Multi-drug resistance (MDR) in Gram-negative organisms is an alarming problem in the world. MDR and extensively-drug resistance (XDR) is in increasing trend due to the production of different types of beta (β)-lactamases. Thus the aim of this study was to document the incidence of MDR and XDR in clinical isolates of Escherichia coli and also to find out the enzymatic mechanisms of β-lactam antibiotics resistance.

Methods

Two hundred clinical isolates of Escherichia coli (E. coli) identified by standard laboratory methods were studied. Antibiotic susceptibility profile was performed for all the isolates and the suspected isolates were phenotypically tested for the production of extended spectrum β-lactamase (ESBL), metallo β-lactamase (MBL) and AmpC β-lactamase (AmpC) by recommended methods.

Results

Around three-fourth (78%) of the total isolates were multi-drug resistant. ESBL, MBL and AmpC production was found in 24%, 15% and 9% of isolates respectively. Amikacin, chloramphenicol and colistin were found to be the most effective antibiotics.

Conclusions

High percentage of MDR was observed. β-lactamase mediated resistance was also high. Thus, regular surveillance of drug resistance due to β-lactamases production and infection control policy are of utmost importance to minimize the spread of resistant strains.

Review on the Antimicrobial Resistance of Pathogens from Tracheal and Endotracheal Aspirates of Patients with Clinical Manifestations of Pneumonia in Bacolod City in 2013

Microbiological content specifically bacterial and fungal etiologies from tracheal aspirates in a tertiary hospital in Bacolod City was reviewed for baseline information. A total of 130 tracheal aspirates were subjected for culture to isolate and identify the pathogen and determine their susceptibilities to various antibiotics. Productions of certain enzymes responsible for antibiotic resistance like ESBL (Extended Spectrum Beta-Lactamase), metallo-β-lactamase, and carbapenemase were also studied. Out of 130 specimens, 69.23% were found to be positive for the presence of microorganisms. Most infections were from male patients aging 60 years and above, confined at the Intensive Care Units (ICU). Pseudomonas aeruginosa and Klebsiella pneumoniae were found to be the most frequent bacterial isolates and non-Candida albicans for fungal isolates, respectively. Among the various antibiotics tested, most isolates were found to be resistant to third generation cephalosporins and penicillins, but susceptible to aminoglycoside Amikacin. On the other hand, production of ESBL and carbapenemase was found to be common among members of Enterobacteriaceae especially K. pneumoniae.

DHA-1 plasmid-mediated AmpC β-lactamase expression and regulation of Klebsiella pnuemoniae isolates

The present study aimed to investigate the regulatory mechanism of the AmpC enzyme by analyzing the construction and function of AmpCR, AmpE and AmpG genes in the Dhahran (DHA)‑1 plasmid of Klebsiella pneumoniae (K. pneumoniae). The production of AmpC and extended‑spectrum β‑lactamase (ESBL) were determined following the cefoxitin (FOX) inducing test for AmpC, preliminary screening and confirmation tests for ESBL in 10 DHA‑1 plasmid AmpC enzymes of K. pneumoniae strains. AmpCR, AmpD, AmpE and AmpG sequences were analyzed by polymerase chain reaction. The pACYC184‑X plasmid analysis system was established and examined by regulating the pAmpC enzyme expression. The electrophoretic bands of AmpCR, AmpD, AmpE and AmpG were expressed. Numerous mutations in AmpC + AmpR (AmpCR) and in the intergenic region cistron of AmpC‑AmpR, AmpD, AmpE and AmpG were observed. The homology of AmpC and AmpR, in relation to the Morganella morganii strain, was 99%, which was determined by comparing the gene sequences of Kp1 with those of Kp17 AmpCR. The specific combination of AmpR and labeled probe demonstrated a band retarded phenomenon and established a spatial model of AmpR. All the enzyme production strains demonstrated Val93→Ala in AmpG; six transmembrane domains were found in AmpE in all strains, with the exception of Kp1 and Kp4, which had only three transmembrane segments that were caused by mutation. The DHA‑1 plasmid AmpC enzymes encoded by plasmid are similar to the inducible chromosomal AmpC enzymes, which are also regulated by AmpD, AmpE, AmpR and AmpG.

A descriptive study of nosocomial infections in an adult intensive care unit in fiji: 2011-12

Nosocomial infections in an intensive care unit (ICU) are common and associated with a high mortality but there are no published data from the Oceania region. A retrospective study in Fiji's largest ICU (2011-12) reported that 114 of a total 663 adult ICU admissions had bacteriological culture-confirmed nosocomial infection. The commonest sites of infection were respiratory and bloodstream. Gram negative bacteria were the commonest pathogens isolated, especially Klebsiella pneumoniae (extended-spectrum β-Lactamase-producing), Acinetobacter, and Pseudomonas species. Mortality for those with a known outcome was 33%. Improved surveillance and implementation of effective preventive interventions are needed.

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.