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

Carbapenem Resistance in Acinetobacter calcoaceticus-baumannii Complex Isolates From Kathmandu Model Hospital, Nepal, Is Attributed to the Presence of bla OXA-23-like and bla NDM-1 Genes

The Acinetobacter calcoaceticus-baumannii (ACB) complex, also known as ACB complex, consists of four bacterial species that can cause opportunistic infections in humans, especially in hospital settings. Conventional therapies for susceptible strains of the ACB complex include broad-spectrum cephalosporins, β-lactam/β-lactamase inhibitors, and carbapenems. Unfortunately, the effectiveness of these antibiotics has declined due to increasing rates of resistance. The predominant resistance mechanisms identified in the ACB complex involve carbapenem-resistant (CR) oxacillinases and metallo-β-lactamases (MBLs). This research, conducted at Kathmandu Model Hospital in Nepal, sought to identify genes associated with CR, specifically blaNDM-1, blaOXA-23-like, and blaOXA-24-like genes in carbapenem-resistant Acinetobacter calcoaceticus-baumannii (CR-ACB) complex. Additionally, the study is aimed at identifying the ACB complex through the sequencing of the 16s rRNA gene. Among the 992 samples collected from hospitalized patients, 43 (approximately 4.334%) tested positive for the ACB complex. These positive samples were mainly obtained from different hospital units, including intensive care units (ICUs); cabins; and neonatal, general, and maternity wards. The prevalence of infection was higher among males (58.14%) than females (41.86%), with the 40-50 age group showing the highest infection rate. In susceptibility testing, colistin and polymyxin B exhibited a susceptibility rate of 100%, whereas all samples showed resistance to third-generation cephalosporins. After polymyxins, gentamicin (30.23%) and amikacin (34.88%) demonstrated the highest susceptibility. A substantial majority (81.45%) of ACB complex isolates displayed resistance to carbapenems, with respiratory and pus specimens being the primary sources. Polymerase chain reaction (PCR) revealed that the primary CR gene within the ACB complex at this hospital was bla OXA-23-like, followed by bla NDM-1. To ensure the accuracy of the phenotypic assessment, 12 samples were chosen for 16s rRNA sequencing using Illumina MiSeq™ to confirm that they are Acinetobacter species. QIIME 2.0 analysis confirmed all 12 isolates to be Acinetobacter species. In the hospital setting, a substantial portion of the ACB complex carries CR genes, rendering carbapenem ineffective for treatment.

Metallo-β-lactamase-producing Pseudomonas aeruginosa Isolates from Two Tertiary Care Centres in a District of Nepal: A Descriptive Cross-sectional Study

INTRODUCTION

Pseudomonas aeruginosa isolates producing metallo-β-lactamase have caused nosocomial outbreaks, severe infections, and ineffective carbapenem therapy worldwide since 1991. Due to their prevalence, hospital infection control techniques are difficult. This study aimed to find out the prevalence of metallo-β-lactamase among P. aeruginosa isolates from two tertiary care hospitals in Kathmandu.

METHODS

A descriptive cross-sectional study was conducted at the Department of Microbiology and Department of Pathology of two tertiary care centres in Kathmandu from 7 December 2021 to 6 April 2023, after receiving ethical approval from the Ethical Review Board. Isolated strains were identified and tested for antibiotic susceptibility by modified Kirby-Bauer Methods. Metallo-β-lactamase presence was confirmed using an imipenem-imipenem/ ethylenediaminetetraacetic acid disc. A convenience sampling method was used. The point estimate was calculated at 95% Confidence Interval.

RESULTS

Among 255, Pseudomanas aeruginosa isolates, the distribution of metallo-β-lactamase-producing Pseudomanas aeruginosa was 103 (40.39%) (34.32-46.69 at 95% Confidence Interval). Multidrug resistance categories included multidrug resistance 74 (71.80%), extensively drug resistance 32 (31.10%), P. aeruginosa difficult-to-treat 16 (15.53%) and carbapenem-resistant P. aeruginosa was determined to be 82 (79.60%).

CONCLUSIONS

The study found a high prevalence of metallo-β-lactamase-producing Pseudomanas aeruginosa isolates, requiring early identification, infection control measures, and an all-inclusive antimicrobial therapy protocol to reduce their spread in medical settings.

Phenotypic and genotypic detection of resistance mechanisms in carbapenem-resistant gram-negative bacteria isolated from Egyptian ICU patients with first emergence of NDM-1 producing Klebsiella oxytoca

Background and Objectives

Carbapenems are considered the last resort to treat several infections, particularly in intensive care units (ICUs). However, increasing carbapenem resistance is problematic because it leads to high morbidity and mortality rates. This study aimed to determine the rate of carbapenem resistance among Gram-negative bacteria collected from patients in ICUs and to identify their resistance mechanisms using phenotypic and genotypic methods.

Materials and Methods

Antimicrobial susceptibility testing was carried out using the disc diffusion method among 180 Gram-negative bacterial isolates. Productions of carbapenemases, metallo-beta-lactamases (MBLs) and the harboring of carbapenemase-encoding genes, were detected in 40 selected carbapenem-resistant Gram-negative bacteria (CR-GNB).

Results

Of 40 selected CR-GNB isolates, 28 (70%), and 20 (50%) isolates were phenotypically positive for carbapenemase, and MBL production, respectively. Furthermore, 22 (55%) showed amplification of one or more of the carbapenemase-encoding genes, including bla _NDM-1, bla _VIM-2, and bla _OXA-48. This study described the first emergence of NDM-1 producing Klebsiella oxytoca in Egyptian ICUs.

Conclusion

High incidence of CR-GNB detected in the ICUs in our study area may be attributed to the overuse of antibiotics, including carbapenems, and improper application of infection control measures. These findings confirm the need for the application of a strict antibiotic stewardship program.

Prevalence of metallo-β-lactamases as a correlate of multidrug resistance among clinical Pseudomonas aeruginosa isolates in Nepal

Pseudomonas aeruginosa is an opportunistic human pathogen that has developed antibiotic resistance (AR) and causes a range of illnesses, including respiratory pneumonia, gastrointestinal infections, keratitis, otitis media and bacteremia in patients with compromised immune system. The production of metallo-β-lactamases (MBLs) is one of the major mechanisms of AR in this bacterium with ensuing infections difficult to treat. The main goal of this study was to provide a quantitative estimate of MBLs producing clinical P. aeruginosa isolates among the Nepalese patients and determine if MBL correlates with multi-drug resistance (MDR). Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guideline was followed for meta-analysis of relevant literature using PubMed, Research4Life, and Google Scholar. The prevalence of MBLs in P. aeruginosa from clinical samples was determined using R 4.1.2 for data pooled from studies published until 2021. The meta-analysis of a total of 19 studies selected (of 6038 studies for which titles and abstracts were reviewed) revealed the prevalence of MBLs producing P. aeruginosa (MBL-PA) was 14 % (95 % CI: 0.10-0.19) while MDR isolates among P. aeruginosa was 42 % (95 % CI: 0.30-0.55) in Nepal. Combined Disc Test was predominantly used phenotypic method for confirming MBLs phenotypes among the studies. Sputum was the most common specimen from which MBL-PA was recovered. A significant positive correlation was observed between MDR and MBL production in P. aeruginosa. We conclude that MBL producing strains are widespread among the clinical isolates of P. aeruginosa in Nepal and responsible for emerging MDR strains. It is paramount that antibiotics prescription against the bacterium should be monitored closely and alternative therapeutic modalities against MBL-PA explored.

Pseudomonas aeruginosa in Nepali hospitals: poor outcomes amid 10 years of increasing antimicrobial resistance

OBJECTIVE

To determine antimicrobial resistance patterns and prevalence of multi- (MDR, i.e., resistant to ⩾3 classes of antimicrobial agents) and extensively (XDR, i.e., resistant to ⩾3, susceptible to ⩽2 groups of antibiotics) drug-resistant strains of Pseudomonas aeruginosa.

METHODS

This was a cross-sectional study conducted in Nepal Mediciti Hospital, Lalitpur, Nepal, using standard microbiological methods with Kirby Bauer disc diffusion to identify antimicrobial susceptibility.

RESULTS

P. aeruginosa (n = 447) were most frequently isolated in respiratory (n = 203, 45.4%) and urinary samples (n = 120, 26.8%). AWaRe Access antibiotics showed 25-30% resistance, Watch antibiotics 30-55%. Susceptibility to AWaRe Reserve antibiotics remains high; however, 32.8% were resistant to aztreonam. Overall, 190 (42.5%) were MDR and 99 (22.1%) XDR (first Nepali report) based on mainly non-respiratory samples. The majority of infected patients were >40 years (n = 229, 63.2%) or inpatients (n = 181, 50.0%); 36 (15.2%) had an unfavourable outcome, including death (n = 25, 10.5%). Our larger study showed a failure of improvement over eight previous studies covering 10 years.

CONCLUSION

Antibiotic resistance in P. aeruginosa occurred to all 19 AWaRe group antibiotics tested. Vulnerable patients are at significant risk from such resistant strains, with a high death rate. Sustainable and acceptable antibiotic surveillance and control are urgently needed across Nepal, as antimicrobial resistance has deteriorated over the last decade.

High prevalence of multidrug-resistant non-fermentative Gram-negative bacilli harboring bla IMP-1 and bla VIM-1 metallo-beta-lactamase genes in Birjand, south-east Iran

Background and Objectives:

Non-fermentative Gram-negative Bacilli (NFGNB) is known as a major cause of healthcare-associated infections with high levels of antibiotic resistance. The aim of this study was to investigate the antibiotic resistance profiles and molecular characteristics of metallo-beta-lactamase (MBL)-producing NFGNB.

Materials and Methods:

In this cross-sectional study, the antibiotic resistance profile of 122 clinical NFGNB isolates was determined by the Kirby-Bauer disk diffusion and microdilution broth methods. Bacterial isolates were investigated for the detection of MBLs production using the combination disk diffusion Test (CDDT). The existence of bla_IMP, bla_VIM, and bla_NDM genes in all carbapenem-resistant isolates was determined employing polymerase chain reaction (PCR) assays.

Results:

High resistance in Pseudomonas aeruginosa was reported to cefotaxime and minocycline, whereas Acinetobacter baumannii isolates were highly resistant to all antibiotics except colistin. Multidrug resistance (MDR)-NFGNB (66% vs. 12.5%, P=0.0004) and extensively drug resistant (XDR)-NFGNB (55.7% vs. 12.5%, P=0.001) isolates were significantly more common in hospitalized patients than in outpatients. The production of MBL was seen in 40% of P. aeruginosa and 93.3% of A. baumannii isolates. It was found that 33.3% and 46.7% of carbapenem-resistant P. aeruginosa isolates, and 13.3% and 28.9% of carbapenem-resistant A. baumannii isolates were harboring bla_IMP-1 and bla_VIM-1 genes, respectively. The incidence of MDR (98.2% vs. 28.3%, P<0.001) and XDR (96.4% vs. 11.7%, P<0.001) in MBL-producing NFGNB isolates was significantly higher than non-MBL-producing isolates.

Conclusion:

This study demonstrated a higher rate of resistance among NFGNB isolates with an additional burden of MBL production within them, warranting a need for robust microbiological surveillance and accurate detection of MBL producers among the NFGNB.

Prevalence of multidrug-resistance and bla VIM and bla IMP genes among gram-negative clinical isolates in tertiary care hospital, Kathmandu, Nepal

Background and Objectives

Carbapenems have been the choice of antibiotics for the treatment of infections caused by multidrug-resistant bacteria. The main objective of this study was to determine the prevalence of carbapenemase (bla _VIM and bla _IMP ) producing isolates among Enterobacteriaceae, Pseudomonas aeruginosa, and Acinetobacter baumannii.

Materials and Methods

A total of 1,151 clinical samples were collected from the patients visiting Annapurna Neurological Institute and Allied Science and Annapurna Research Centre, Kathmandu, between June 2017 and January 2018. Antibiotic susceptibility testing (AST) was performed on the Enterobacteriaceae, P. aeruginosa and A. baumannii isolates using the Kirby-Bauer disk diffusion method. The modified Hodge test (MHT) was performed on the carbapenem-resistant isolates to confirm carbapenemase production. DNA was extracted and then screened for bla _VIM and bla _IMP genes by multiplex PCR.

Results

Of the total 1,151 clinical samples, 253 (22.0%) showed positive growth. Of them, 226 (89.3%) were identified as Enterobacteriaceae, P. aeruginosa, and A. baumannii. Among the 226 isolates, 106 (46.9%) were multidrug-resistant. Out of the 106, 97 (91.5%) isolates showed resistance to at least one of the carbapenem used. Among the 97 carbapenem-resistant isolates, 67 (69.1%) showed the modified Hodge test (MHT) positive results. bla _VIM and bla _IMP were detected in 40 and 38 isolates respectively using multiplex PCR assay.

Conclusion

This study determined a high prevalence of MDR and carbapenem resistance among Enterobacteriaceae, P. aeruginosa, and A. baumannii as detected by the presence of bla _VIM and bla _IMP genes. This study recommends the use of rapid and advanced diagnostic tools along with conventional phenotypic detection methods in the clinical settings for early detection and management of drug-resistant pathogens to improve treatment strategies.

Bacterial etiology of sputum from tuberculosis suspected patients and antibiogram of the isolates

OBJECTIVE

The current study aims to explore the bacteriology of sputum of tuberculosis (TB) suspected patients. A cross-sectional study was carried out in the sputum samples of 150 TB suspected patients visiting District Public Health Office, Bharatpur, Nepal. The samples were subjected to cultural, microscopic and biochemical analyses for the identification of the isolates. In addition, antibiotic susceptibility tests were carried out with a special focus on ESBL and MBL production following Clinical and Laboratory Standard Institute guidelines.

RESULTS

Bacterial growth was recovered in 47% (71/150) of the TB suspected patients of which 12.66% (19/150) had pulmonary TB infection. Streptococcus spp. (9%) and Pseudomonas aeruginosa (9%) were the most frequently isolated bacteria. Enterobacteriaceae accounted for 35% of the total isolates. Occurrence of bacterial pathogens was more in males (69%) than in females (31%).The incidence of bacterial pathogen was seen associated with gender of the patients and with the TB infection (p < 0.05) but independent with age of the patients and HIV infection (p > 0.05). Tetracycline was effective against Streptococcus spp. whereas gentamicin was effective against Bacillus species. Imipenem and co-trimoxazole were effective drugs for Gram-negative isolates. Among 83 isolates, 35 were multi-drug resistant, 9 were ESBL producers and 4 were MBL producers.

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.

A matched case-control study to assess the carbapenem-resistant Enterobacteriaceae infections among hospitalized children at King Fahad Medical City, Riyadh, Saudi Arabia

OBJECTIVES

To identify risk factors associated with carbapenem-resistant Enterobacteriaceae (CRE) infections among hospitalized children at King Fahad Medical City, Riyadh, Saudi Arabia.

METHODS

A retrospective matched case-control study was conducted in pediatric patients with CRE infection at King Fahad Medical City, Riyadh, Saudi Arabia between January 2016-2017.

RESULTS

During the study period, 19 CRE cases and 37 controls were identified for analysis. Children  ≤17 years (mean age±SD for cases was 43.9±46 months and controls was 29.2±52.2 months) were included in the study. Several factors associated with CRE infections were identified, which included, central venous catheter (CVC) line placement (p=0.023; confidence interval [CI]: 0.97-85.77), recent surgical procedures (p=0.006; CI: 1.30-9.28), invasive procedures (p greater than 0.001; CI: 1.98-21.18), use of prior antibiotics (p=0.008; CI: 1.38-24.62), and carbapenem exposure in the past 3 months (p=0.004; CI: 1.09-12.20). Among the cases, Klebsiella pneumonia was the most commonly identified (47%) followed by Escherichia coli (31%). Carbapenem-resistant Enterobacteriaceae was associated with increased comorbidities and prolonged hospitalization however, no mortalities were reported.

CONCLUSION

This study identified prior antibiotic exposure, recent surgery and the use of invasive procedures as significant risk factors for colonization or infection with CRE. Also, the need for public awareness, continuing education for healthcare professionals, optimum use of invasive devices, enhanced surveillance, and antimicrobial stewardship are highlighted here which can limit CRE transmission in healthcare facilities.

Prevalence of metallo-β-lactamase acquired genes among carbapenems susceptible and resistant Gram-negative clinical isolates using multiplex PCR, Khartoum hospitals, Khartoum Sudan

Background

The increased prevalence of carbapenem-resistant Gram-negative isolates caused by Metallo-β-lactamase (MBL) is worrisome in clinical settings worldwide. The mortality rate associated with infections caused by MBLs producing organisms ranging from 18 to 67%.

This study aimed to determine the prevalence of Metallo-β-lactamase genes among some Gram-negative clinical isolates (Carbapenems susceptible and resistant).

Methods

This paper describes a descriptive cross-sectional study carried out to detect MBL genes such as (blaVIM, blaIMP and blaNDM) by multiplex PCR mixture reaction among 200 Gram-negative clinical isolates (Citrobacter spp, Escherichia coli, Enterobacter spp, Klebsiella pneumoniae, Pseudomonas aeruginosa, Proteus mirabilis, Proteus valgaris). Khartoum hospitals during 2015 to 2016.

Limitation: The study organisms were not evaluated for non-MBL carbapenemases, such as KPC and OXA-48.

Results

The prevalence of MBL genes by multiplex PCR assays among 200 Gram-negative clinical isolates was 72(36.1%). MBL positive genes among 100 carbapenems sensitive and 100 resistant isolates were 27(27%) and 45(45%) respectively. There was a statistically, significant association between the antimicrobial susceptibility and the presences of MBL genes (P.value = 0.008).

E.coli was the predominant species possessing MBL genes 26(36.1%), with 22(30.7%) species having a combination of MBL genes.

Verona integron Metallo beta-lactamase (VIM) was the most frequent genes 28(38.9%) out of 72 MBL detected genes, followed by imipenemase (IMP) was 19(26.4%), and consequently, New Delhi Metallo beta lactamase was 3(4.2%).

Conclusion

This study revealed a high prevalence of MBL genes in some Gram-negative isolates from Khartoum State Hospitals which were not previously established in these hospitals.

Electronic supplementary material

The online version of this article (10.1186/s12879-018-3581-z) contains supplementary material, which is available to authorized users.

Detection of metallo-β-lactamases-encoding genes among clinical isolates of Pseudomonas aeruginosa in a tertiary care hospital, Kathmandu, Nepal

Objectives

This study was carried out to determine the prevalence of metallo-β-lactamases (MBLs) producing Pseudomonas aeruginosa in imipenem-nonsusceptible isolates and to detect MBL-encoding genes among MBLs-positive isolates.

Results

Metallo-β-lactamases production was detected in 68.6% isolates of P. aeruginosa with reduced susceptibility to imipenem. The bla_VIM-2 gene was detected in 75% isolates and bla_IMP-1 was detected in 25% isolates. All MBLs-positive isolates were multidrug resistant with a high level of resistance to imipenem (MIC 16 to ≥ 32 µg/ml), meropenem (MIC 16 to ≥ 32 µg/ml), and ceftazidime (MIC 64 to ≥ 512 µg/ml). All MBL-positive isolates were susceptible (MIC ≤ 2 µg/ml) to colistin. We found high prevalence of MBL-producing P. aeruginosa. To our knowledge this is the first report of detection of bla_VIM-2 and bla_IMP-1 in P. aeruginosa from Nepal. This indicates the need for awareness to prevent the spreading of these resistant isolates in hospital setting.