Isolates Of Acinetobacter Species Research Articles

Detection of Metallo β-Lactamase in Acinetobacter Species Using Phenotypic Methods with their Antibiotic Resistance Profile in Tertiary Care Hospital

Background: Acinetobacter species are commonly found in nature, in water, and in soil, and also, and they have been isolated from humans and animals. In the hospital setting, Acinetobacter species has emerged as a major opportunistic pathogen, being able to colonize and develop infections in patients. In Acinetobacter species, β-lactamases and outer membrane alterations are likely to function together to impart resistance. Understanding the epidemiology, and resistance mechanism, and for infection management and preventing a potential global health crisis, techniques for identifying Carbapenem-Resistant-Acinetobacter species are essential. Aim: To detect Metallo β-Lactamase (MBL) in Acinetobacter species with their antimicrobial susceptibility pattern. Material and Methods: 100 Acinetobacter species isolates from various clinical samples such as blood, cerebrospinal fluid, sputum, bronchoalveolar lavage, pus, urine, wound swab, and body fluids were included in the study. Phenotypic tests such as, Disc Potentiation test & Modified Hodge test were used to detect the presence of Metallo β-lactamase in imipenem & meropenem-resistant isolates. Results: The highest prevalence of Acinetobacter was found in blood (37%), followed by sputum (31%) and others [pus, urine, ascitic fluid, cerebrospinal fluid (CSF), bronchoalveolar Lavage (BAL), and pleural fluid]. A maximum number of Acinetobacter were isolated from MICU followed by medicine and surgery. The Modified Hodge test yielded the largest percentage of MBL-positive Acinetobacter isolates (67.26%) when compared to the Disc Potentiation test method (50.45%). Conclusion: Early detection of Metallo β-lactamase production is essential for planning appropriate treatment according to the resistance mechanisms of the multi-drug resistant strains, as well as for efficient infection control procedures to prevent the spread of infection.

The Distribution of Carbapenem-Resistant Acinetobacter Species and High Prevalence of CC92 OXA-23-Producing Acinetobacter Baumannii in Community Hospitals in South Korea.

Clinical isolates of Acinetobacter species in South Korea are continuously exhibiting high rates of antimicrobial resistance to carbapenems, indicating that there are public health concerns among both healthcare-associated infections and community-associated infections. The aim of this study was to describe the prevalence and characteristics of carbapenem-resistant Acinetobacter isolates originating from community hospitals. A total of 817 non-duplicated Acinetobacter species were isolated from December 2022 to July 2023 at long-term care facilities and general hospitals in 16 regions geographically distributed throughout South Korea. Bacterial identification and antimicrobial susceptibility testing were performed using the VITEK-2 system. The bacteria were identified as Acinetobacter baumannii by blaOXA-51 PCR and as non-baumannii Acinetobacter species by rpoB sequence analysis. The carbapenem resistance genes (OXA-23, OXA-48, OXA-58, IMP, VIM, NDM, GES, and KPC) were identified via PCR and sequencing. The genetic relatedness of carbapenem-resistant A. baumannii (CRAB) isolates was assessed by multilocus sequence typing. A total of 659 A. baumannii and 158 non-baumannii Acinetobacter isolates, comprising 19 different species, were identified in all 16 regions. The carbapenem resistance rate was 87.4% (n=576) for the A. baumannii isolates, and all the strains produced blaOXA-23. For non-baumannii Acinetobacter, the rate of carbapenem resistance was 8.9% (n=14); this resistance was primarily caused by blaOXA-23 (n=9), followed by blaNDM-1 (n=3) and blaVIM-2 (n=2). Of the 576 CRAB isolates, clonal complex 92 (CC92) was the predominant genotypes, followed by sequence type 229 (ST229), ST373, ST397, ST447, and ST620. Our results showed the distribution of Acinetobacter species and showed that CC92 CRAB clinical isolates with widespread production of blaOXA-23 were predominant in community hospitals. Our findings suggest that there is a need for urgent and effective methods to reduce carbapenem resistance in A. baumannii in South Korea.

Prevalence of Extended-spectrum Beta-lactamase (ESBL), Metallo Beta-lactamase (MBL) and Carbapenemase Producing Acinetobacter Species Isolated from Various Clinical Samples in Tertiary Care Hospital

Acinetobacter is an important nosocomial pathogen causing health care associated infections. It is highly antibiotic resistant gram-negative bacilli. The study was done to determine the prevalence of Acinetobacter species isolated from various clinical samples with their antibiotic susceptibility pattern. To determine the antimicrobial susceptibility pattern of the isolated Acinetobacter species and also the multidrug resistant mechanisms by phenotypic characterization. The retrospective study was carried out in patients diagnosed with Acinetobacter infection in the Microbiology Department, Krishna Institute of Medical Sciences, Krishna Vishwa Vidyapeeth, Deemed To Be University, Karad, a tertiary care hospital, including the clinical departments, during the period of two years from November 2020 till November 2022. Organism identification, biochemical test, antibiotic resistance pattern and phenotypic tests such as ESBL, MBL and Carbapenemase production were performed as per the Clinical and Laboratory Standards Institute (CLSI). The Modified Hodge test (MHT) was performed for Carbapenemase production detection in Acinetobacter species. A total of 150 Acinetobacter species were isolated from clinical samples. Acinetobacter baumannii was the most prevalent species 138 (92%), followed by Acinetobacter lwoffii 10 (7%) and Acinetobacter hemolyticus 2 (1%). The isolates showed highest resistance to Ampicillin 130 (87%) and sensitive to Colistin 113 (75.3%). Most of the isolates of of Acinetobacter baumannii showed maximum ESBL 21(14%) and MBL 75 (93%) production. Modified Hodge test showed positive results in Acinetobacter baumannii, only 11 (7%). The study showed that Acinetobacter baumannii was the most prevalent species showing drug resistance by phenotypic detection methods. At present Acinetobacter is a frequent pathogen in hospital acquired infections in critically ill patients admitted to ICU. The isolates of Acinetobacter species in our study showed resistant to most commonly used antibiotics. The study showed that ESBL production in Acinetobacter was 22 (15%) and MBL 80 (53%). Most Acinetobacter isolates were Multi Drug Resistant (MDR). MDR Acinetobacter is widely increasing due to inappropriate use of antibiotics in healthcare hospital. In our study, detection of carbapenemase by Modified Hodge test was positive in 11 (7%) isolates.

Isolation and Speciation of Acinetobacter Species with Special Reference to Antibiotic Resistance in Tertiary Care Hospital

Acinetobacter can survive longer in the environment and is also known for developing resistance against agents like disinfectants and nutritional deprivation. Very restricted information about Acinetobacter is available because of their confused taxonomic status. The isolation and identification of resistance pattern help in the selection and search for new antibiotics, reducing the morbidity and mortality of patients. The present study was conducted to find the different types of resistant mechanisms in Acinetobacter species and their antimicrobial susceptibility pattern from various clinical samples. Gram's stain and biochemical reactions identified Acinetobacter isolated from various clinical samples. Antibiotic susceptibility testing was done, and their resistant pattern was observed. Phenotypic methods for drug resistance were carried out -Detection of Extended Spectrum Beta Lactamase (ESBL) by Double disc synergy test (DDST), detection of Metallo Beta Lactamase (MBL) by Imipenem with EDTA, and detection of Carbapenemase production by Modified Hodge test (MHT). The results showed that out of 150 isolates of Acinetobacter species, Acinetobacter baumannii 138 (92%) was the most common species isolated, followed by Acinetobacter lwoffii 10 (7%) and Acinetobacter hemolytic 2 (1%). Of these, 22 (15%) isolates showed ESBL production by Double disc synergy test, 80 (53%) isolates were MBL producers, and 11 (7%) were Carbapenemase producers by Modified Hodge test. The study observed that ESBL production in Acinetobacter was 22(15%) and MBL 80(53%). It demonstrated that most of the Acinetobacter isolated were found to be Multi-Drug Resistant (95%). It brings out the need for active surveillance combined to eradicate the curtail of this organism in hospital settings.

Role of Matrix-Assisted Laser Desorption Ionization-Time-of-Flight Mass Spectrometry for Species Identification of Acinetobacter Strains.

Introduction Acinetobacter species has become a leading cause of nosocomial infections in recent years. Objectives The aim of the study was to establish the usefulness of matrix-assisted laser desorption ionization-time-of-flight (MALDI-TOF) mass spectrometry (MS) for the identification of Acinetobacter species with respect to conventional biochemical methods and MicroScan WalkAway 96 Plus system and to compare the antibiotic susceptibility test results Kirby-Bauer disk diffusion method with MicroScan WalkAway 96 Plus automated identification and antimicrobial susceptibility testing system. Materials and Methods The study sample comprised 100 clinical isolates of Acinetobacter species. They were all identified using MALDI-TOF MS and compared with other two identification systems. Statistical Analysis Comparison of categorical variables by Fisher's exact test or Pearson's chi-square test was done. All statistical tools were two tailed, and a significant level p < 0.05 was used. All statistical tests were performed using SPSS v22.0 (Armonk IBM Corp., New York, United States). Cohen's kappa coefficients were also calculated and used as applicable. Results MALDI-TOF MS revealed 92 A. baumannii , 2 Acinetobacter nosocomialis , 3 Acinetobacter lwoffii , and 1 each was identified as Acinetobacter junii , Acinetobacter johnsonii , and Acinetobacter tandoii . There was moderate agreement between identification by MicroScan WalkAway and MALDI-TOF, and substantial agreement between conventional biochemical tests and MALDI-TOF. We found that there was a 100% categorical agreement with respect to susceptibility of aminoglycosides (amikacin, gentamicin, tobramycin) and cephalosporins (ceftazidime, cefepime, cefotaxime) between disk diffusion method and MicroScan WalkAway 96 Plus system. Total of 16 errors were observed. Conclusion Although MALDI-TOF MS could be useful to identify A. baumannii but not other species in the genus, it is a rapid, reliable method and can be routinely used in clinical laboratories.

PHENOTYPIC DETECTION OF METALLO BETA LACTAMASE IN CARBAPENEM RESISTANT ACINETOBACTER SPECIES IN INTENSIVE CARE UNIT IN A TERTIARY CARE HOSPITAL

Introduction: Acinetobacter causes a wide range of illness in debilitated and hospitalized patients. Carbapenem resistance in Acinetobacter species is an emerging problem and is a cause of concern as many nosocomial infections with Acinetobacter species are resistant to most other antibiotics. The present study was aimed to study metallo-β-lactamase (MBL) production in Acinetobacter species. Data Material and Methods: was collected retrospectively from October 2021 to March 2022. Out of all the clinical samples obtained (respiratory secretions, pus, blood &amp; urine), all Carbapenem resistant isolates of Acinetobacter species were included. Antimicrobial susceptibility testing was done by standard Kirby Bauer disk diffusion method. MBL detection was done by imipenem-EDTA combined disk method and Modied Hodge test. Out of total Results: 325 Acinobacter isolates isolated from intensive care unit (ICU), 228 were found to be carbapenem (Imipenem &amp; Meropenem) resistant and these were further processed for MBL production. Out of 228 Carbapenem resistant Acinetobacter isolates 198 (86.84%) and 170 (74.56%) were found MBL producer by Combined Disc test and Modied Hodge Test respectively. This Conclusion: study demonstrated that multidrug resistant strains of Acinetobacter are common in ICU of tertiary care hospitals. Unwarranted and unrestricted usage of antibiotics and production of MBL is associated with emergence of resistance in nosocomial pathogens. Regular monitoring and documentation of carbapenem resistant is crucial in developing strategies to control infection due to these bacteria.

Isolation of Acinetobacter Species from Wound Infection and Their Antimicrobial Resistance Pattern in a Tertiary Care Hospital in Rajshahi, Bangladesh

Background: Acinetobacter species has emerged as an important pathogen globally in various infections especially in hospital acquired infections. Objectives: This study was conducted to determine the antibiotic resistance pattern of Acinetobacter species from wound swab samples. Materials and Methods: A Cross sectional study was undertaken in Department of Microbiology, Rajshahi Medical College (RMC), Rajshahi, Bangladesh from period January 2014 to December 2014. A total 13 Acinetobacter were collected from 292 wound infection patients of surgery word and its allied brances in Rajshahi medical college hospital (RMCH). Isolation, Identification and sensitivity of Acinetobacter species were performed by manual method. Results: Out of 292 patients 13(4.4%) patients showed growth of Acinetobacter species. Resistance observed to Meropenem was 38.46%, Piperacillin -Tazobactum 61.53%, Amikacin 53.84%, Ceftazidime 76.92%, Gentamicin 61.53% and Levoflaxacin 67.23%. This data suggest that Acinetobacter isolated from hospital exhibits resistanace to multiple antimicrobial drugs. Conclusion: The study will help to implement better infection control strategies and improve the knowledge of antibiotic resistance patterns of Acinetobacter species in our region.

Comparison of Colistin MIC by Microbroth Dilution, E-Test and Vitek-2, in Isolates of Acinetobacter spp. Isolated from Bloodstream Infections

Background: Acinetobacter species are leading cause of nosocomial infections, causing significant morbidity and mortality globally including India. Being persistent in the hospital environment and rapidly developing resistance to a wide variety of antibiotics are the most important features of this pathogen. The present study aimed to compare Colistin MIC of Acinetobacter species isolated from the blood samples by E test and Vitek 2 to the standard broth micro dilution test. Methodology: Two antibiotic susceptibility test methods, The Vitek-2 and the E test, against the reference broth micro dilution method in terms of the various parameters such as Reproducibility, reliability, cost and time effectiveness. Data obtained from the current study regarding antimicrobial resistance of Acinetobacter species recovered from clinical specimens referred to microbiology laboratory of SKIMS and was analyzed by using SPSS20.0. Results: Out of 100 isolates of Acinetobacter species analyzed from blood specimens the distribution of Acinetobacter species according to different clinical diagnosis of patients 89% were A. baumannii and 11% were A. lwoffii. Seventy three percent of them were from males and 27% of them were from females with a mean age of 39.6 (SD±27.46). Regarding the specimen and isolate sources, the majority were from ICU (54%), Surgical ward (26%), Medical ward (16%) and 4% from Outpatient department of SKIMS. Significant descending trends of antimicrobial resistance was shown for Amoxicillin/Clavulanic acid, Cefoperazone/ Sulbactam combination, Cotrimoxazole (100%), Levofloxacin (92%) Piperacillin/Tazobactam, Ciprofloxacin (90%), Cephalosporins (&gt;80%), Imipenem and Meropenem (76%), Amikacin (68%), Gentamycin (67%), Tigecycline (11%) and 0% for Colistin respectively. Conclusion: from the study it could be concluded that the best reference method for testing susceptibility to the Polymyxins still remains to be defined. However, in routine clinical practice in most regions worldwide, where a reference method can hardly be implemented, the interpretation of Colistin susceptibility should preferably be based on results of automated systems such as Vitek-2 or the E test. The micro broth Dilution method remains the most reliable and reproducible, however most tedious and time-consuming method. Colistin remains a very effective, least resisted drug for MDR Acinetobacter species as compared by all the three methods. Keywords: Acinetobacter species; Antimicrobial resistance; Colistin; E test and Vitek 2.

Microbiological, Phenotypic Characteristics, Antimicrobial Resistance Profile and Molecular Identification of Acinetobacter species Isolated from Meat of Different Sources in Egypt

Although food is very important for the human life, it may be life threatening. Foodborne diseases are spreading worldwide through the increasing rate of fresh and undercooked food consumption. Foodborne pathogens include many types of bacterial species. This study was conducted to determine the prevalence of Acinetobacter species isolated from meat samples, as well as their phenotypic characteristics, antimicrobial resistance profiles; and genotypic characteristics. A total of 110 samples, collected from chickens (n=50), beef (n=44), rabbits (n=10), and mutton (n=6), were examined bacteriologically. The suspected colonies were identified biochemically and then tested for their antimicrobial resistance, biofilm formation, and hemolytic activity, Identification was confirmed by Polymerase Chain Reaction (PCR) for the genes; rpoB, tarT, fimH, and espA. Nine Acinetobacter species isolates (8.2%) were recovered. Fifty five samples resulted in the isolation of non-lactose fermenters with an incidence of 50%, 29 produced late lactose fermenters with an incidence of 26% while, the rest of samples showed no growth or non-lactose fermenters. On antibiogram, the isolates showed high resistance to ceftriaxone, imipenem, ceftazidime and ticarcillin/clavulanic acid in percentages of 89%, 77.8%, 66.7% and 66.7 %, respectively. While, low resistance was found to sulfamethazole/trimethoprim, doxycycline and amikacin in percentages of 44.4%, 33.3% and 11.1%, respectively. However, the isolates showed no resistance to ciprofloxacin. All the isolates were MDR with MDRindex (more than 0.5), only one isolate was weak biofilm producer but, no isolates produced hemolysis of the sheep RBCS. Genetically, 88.9% of the isolates expressed tarT and fimH genes while only 5.6% of the isolates expressed espA gene. It can be concluded that Acinetobacter species are to be considered when inspecting meat samples of different sources.

Antimicrobial Resistance Profiling of Routine Antibiotics and Mango Kernel (Mangifera Indica L.) Ethanolic Extract on Multidrug-Resistant Acinetobacter Isolates

Multidrug-resistant (MDR) Acinetobacter species are opportunistic pathogens that are clinically important, which causes severe infection during a prolonged stay in an Intensive Care Unit (ICU) of the hospital. In the present study, we screened clinical isolates of Acinetobacter species for its MDR nature from the ICU of a tertiary care centre at Abha, Saudi Arabia during the period of 2013-2017. Confirmed MDR Acinetobacter species clinical isolates were challenged against ethanolic extracts from mango kernel (Mangifera Indica L.) by classical disc diffusion method. In total, we characterized 124 MDR Acinetobacter isolates, out of which 62 (50%) were Acinetobacter baumannii (MDR-AB), 41 (33.1%) were Acinetobacter baumannii complex (MDR-ABC), 15 (12.1%) were Acinetobacter baumannii-haemolyticus (MDR-ABH), 3 (2.4%) were Acinetobacter haemolyticus (MDR-AH) and 3 (2.4%) were Acinetobacter iwoffii (MDR-AI). We observed that MDR-AB isolates were inhibited by ethanolic extract of M. indica with minimum inhibition concentration (MIC) of 0.25 mg/ml. Concentrations of 50 mg/mL, 5 mg/mL and 0.5 mg/mL exhibited average inhibition zones of 18.74±0.09, 15.51±0.08 and 9.74±0.06 mm respectively showing a concentration dependent antagonisms (R2= 0.947). The results of M. indica were comparable to Colistin inhibition zone of 14.98±0.72 mm with 50 mg/mL and 5 mg/mL exceeded those of the positive control (p= 0.6721 and 0.1045, respectively). However, Colistin showed minor increase over M. indica at the concentration 0.5-mg/ mL (p= 0.5384). More specifically, MDR-AB strains have shown a substantial susceptibility to mango kernel extract (0.25 mg/mL) with antagonism similar to that of Colistin. Thus, the study shows that the extracts of mango kernel as a potential drug target and could be potentially used as an adjunct treatment along with the standard agents to treat Acinetobacter infections.

Carbapenem resistance in Pseudomonas aeruginosa and Acinetobacter species at a large tertiary referral hospital in Lusaka, Zambia

BackgroundPseudomonas aeruginosa (P. aeruginosa) and Acinetobacter species and are among the leading causes of hospital-acquired infections (HAI). Treating patients with HAI caused by these pathogens is usually a challenge due to intrinsic and acquired resistance to the commonly used and affordable antibiotics, which has been heightened by the emergence of metallo-β lactamases thereby exhibiting resistance to carbapenems. Currently, carbapenem resistance represents an increasing problem in the health care settings globally but there is still a paucity of data on carbapenem resistance in our setting. ObjectiveTo detect carbapenem resistance and the susceptibility to other antimicrobial agents in P. aeruginosa and Acinetobacter species isolated from blood, sputum, skin and soft tissue specimens between March, 2018 and June, 2019 at the University Teaching Hospital (UTH), Lusaka, Zambia. MethodThis was a retrospective hospital based study, involving routine blood, sputum, skin and soft tissue samples submitted to the microbiology laboratory. Conventional microbiology methods were used to identify the organisms, while Kirby-Bauer disc diffusion method was used to determine the antimicrobial susceptibility profiles of the isolates. In order to detect carbapenemase production in P. aeruginosa isolates that were resistant to imipenem by disc diffusion, the isolates were subjected to the modified carbapenem inactivation method (mCIM) method. ResultsA total of 384 samples were analyzed, of which 84 P. aeruginosa and 11 Acinetobacter species were isolated. The P. aeruginosa isolates were susceptible to imipenem (94%), piperacillin-tazobactum (95.2%), amikacin (91%), ciprofloxacin (69%), gentamicin (63.1%) and ceftazidime (51.2%). The Acinetobacter species isolates were most susceptible to amikacin (90.9%), imipenem (82.9%) and piperacillin-tazobactum (82.8%), ciprofloxacin, tetracycline and cefepime all at 27.3% each but had the lowest susceptibility at 9.1% to both gentamicin and cefotaxime. Carbapenem resistance in P. aeruginosa was 5/84 (6%) and 2/11 (18.2%) in Acinetobacter species. Carbapenemase production was confirmed in all five P. aeruginosa isolates. ConclusionCarbapenem resistance was low in both organisms demonstrating that imipenem is still an effective treatment choice for invasive infections caused by these organisms in our setting. In order to reduce HAI and improve patient outcome, there is need to strengthen antimicrobial surveillance/stewardship and infection control at the UTH.

English

BACKGROUND Acinetobacter species are important infectious agents worldwide especially in healthcare settings. It has the ability to develop various resistance mechanisms to various antibiotics. We wanted to study the role of tigecycline and minocycline in the treatment of multidrug resistant Acinetobacter species. METHODS 254 non-repetitive isolates of Acinetobacter species from various clinical samples like exudates, blood, sputum, urine were retrospectively studied. Antibiotic susceptibility testing was done by Vitek 2 compact system. Susceptibility of the carbapenem resistant isolates towards tigecycline and minocycline were analysed. RESULTS 205 (80.7 %) isolates were resistant to either of the carbapenem drugs and 49 (19.3 %) were sensitive to all the 3 carbapenems, namely imipenem, meropenem and doripenem. 54.1 % isolates were sensitive to tigecycline while sensitivity towards minocycline was 40.5 %. The degree of sensitive concordance in the susceptibility to minocycline and tigecycline against Acinetobacter species was 31.1 %, which indicated fair agreement statistically. 21.1 % isolates were resistant / intermediate to minocycline but sensitive to tigecycline. Only 9.4 % isolates which were resistant to tigecycline were sensitive to minocycline. CONCLUSIONS The results of the present study have demonstrated that minocycline and tigecycline are effective against the carbapenem resistant Acinetobacter species. Tigecycline can be considered as a therapeutic agent for the treatment of multidrug resistant Acinetobacter which are otherwise difficult to inhibit using other antibiotics. KEY WORDS Carbapenem Resistance, Tigecycline, Minocycline, Antimicrobial Resistance

Activity of Cefiderocol and Comparators against Isolates from Cancer Patients.

Cefiderocol inhibited 97.5% of 478 Gram-negative isolates from cancer patients at ≤4 mg/liter. It had potent activity against extended-spectrum β-lactamase-positive Enterobacteriaceae, carbapenem-resistant Enterobacteriaceae (CRE), and nonfermenting Gram-negative bacilli, including Pseudomonas aeruginosa, Stenotrophomonas maltophilia, and Acinetobacter species isolates. Amikacin, ceftazidime-avibactam, and meropenem had appreciable activity against non-CRE Enterobacteriaceae No comparators were active against multidrug-resistant P. aeruginosa isolates. Only trimethoprim-sulfamethoxazole had appreciable activity against S. maltophilia isolates. Overall, cefiderocol was associated with the lowest level of resistance.

Evaluation of the NG-Test MCR-1 Lateral Flow Assay and EDTA-Colistin Broth Disk Elution Methods To Detect Plasmid-Mediated Colistin Resistance among Gram-Negative Bacterial Isolates.

Plasmid-mediated colistin resistance (PMCR) is a global public health concern, given its ease of transmissibility. The purpose of this study was to evaluate two methods for the detection of PMCR from bacterial colonies: (i) the NG-Test MCR-1 lateral flow immunoassay (LFA; NG Biotech, Guipry, France) and (ii) the EDTA-colistin broth disk elution (EDTA-CBDE) screening test method. These methods were evaluated using a cohort of contemporary, clinical Gram-negative bacillus isolates from 3 U.S. academic medical centers (126 isolates of the Enterobacterales, 50 Pseudomonas aeruginosa isolates, and 50 Acinetobacter species isolates; 1 isolate was mcr positive) and 12 mcr-positive CDC-FDA Antibiotic Resistance (AR) Isolate Bank isolates for which reference broth microdilution colistin susceptibility results were available. Eleven (4.6%) isolates were strongly positive by the MCR-1 LFA, with an additional 8 (3.4%) isolates yielding faintly positive results. The positive percent agreement (PPA) and negative percent agreement (NPA) for MCR-1 detection were 100% and 96.1%, respectively. Upon repeat testing, only a single false-positive MCR-2 producer remained, as the isolates with initially faintly positive results were negative. The EDTA-CBDE screening method had an overall PPA and NPA of 100% and 94.3%, respectively. The NPA for the EDTA-CBDE method was slightly lower at 94.2% with Enterobacterales, whereas it was 96.0% with P. aeruginosa The MCR-1 LFA and EDTA-CBDE methods are both accurate and user-friendly methods for the detection of PMCR. Despite the rarity of PMCR among clinical isolates in the United States, these methods are valuable tools that may be implemented in public health and clinical microbiology laboratories to further discern the mechanism of resistance among colistin-resistant Gram-negative isolates and to detect PMCR for infection prevention and control purposes.

Impact of Efflux Pump Inhibitor Carbonyl-Cyanide M-Chlorophenylhydrazone in Multidrug Resistant AcinetobacterSpecies Isolates from Sterile Body Fluids

Introduction: Antimicrobial resistance of Acinetobacter baumannii(A. baumannii) are rapidly emerging, becoming non-responsive to most of the commonly prescribed antibiotics and leaving us with few treatment options and galloping treatment costs. Aim: To study the effect of Efflux Pump Inhibitor (EPI) Carbonyl Cyanide 3-Chlorophenylhydrazone (CCCP) on Multidrug Resistance (MDR) A. baumannii isolates from different sterile body fluids. Materials and Methods: A total of 40 Acinetobacter species isolates from different sterile body fluids i.e., Cerebrospinal Fluid (CSF), ascitic fluid, pleural fluid, and peritoneal fluid were collected and identified by Matrix Assisted Laser Desorption/Ionisation-Time Of Flight (MALDI-TOF), Biomerieux, France. Minimum Inhibitory Concentration (MIC) of A. baumannii was determined by automated VITEK-2 Antimicrobial Susceptibility Testing (AST) system (Biomerieux, France). In addition, MIC of the isolates, grown on Mueller-Hinton Agar (MHA) plate with 15 μg/mL with EPI CCCP (Sigma Aldrich, US) was determined. For Tigecycline, MIC was determined by Broth Microdilution (BMD) method. Results: Out of 40 isolates, 34 (85%) were A. baumannii and 6 (15%) were Acinetobacter junii. Most of the Acinetobacter spps were MDR and only susceptible to few antibiotics. Most effective antibiotic was Tigecycline 25 (73.52%) followed by Co-trimoxazole 10 (29.41%). Similarly, Out of 40 isolates, 2 to 64 folds reductions in MIC was observed due to CCCP in 10 (25%) isolates for various antibiotics. Likewise, for Tigecycline, 2 to 4 folds reductions in MIC value (One strain changed from intermediate to sensitive) was observed by VITEK-2 AST which corroborated with reduction in MIC by BMD after addition of CCCP. Conclusion: MDR A. baumannii are spreading rapidly. There is the need to overcome the antimicrobial resistance by investigating resistance inhibiting substance that will help to restore antimicrobial susceptibility and bringing back the existing antibiotics in prescription.

Beta-Lactamases Production in Multi-drug Resistant Acinetobacter species Isolated from Different Clinical Specimens

Objectives: To determine the prevalence of Acinetobacter spp. from different clinical specimens and detect different types of β-lactamase enzymes.&#x0D; Methods: Different clinical samples were collected and 125 Acinetobacter spp. were isolated. Various biochemical tests were carried out to speciate the Acinetobacter spp. The antibiotic susceptibility pattern and β-lactamase enzymes like Extended spectrum β-lactamase (ESBL), Metallo β-lactamase (MBL) and AmpC β-lactamase were determined.&#x0D; Results: Of the total 125 isolates, the most predominant species was Acinetobacter calcoaceticus-A. baumannii (Acb) complex (80%). Highest rate of isolation of Acinetobacter species were from in-patients (neonates’ blood sample). Among all, 44.8% isolates were found to be MDR with the majority being resistant to aminoglycosides, carbapenems and fluoroquinolones but not to colistin. ESBL, MBL and AmpC beta-lactamase was detected in 43.2%, 15.2% and 1.6% of the isolates respectively.&#x0D; Conclusion: Acinetobacter calcoaceticus-A. baumannii complex should be considered for detection in hospitalized patients. The analysis of antibiotic susceptibility pattern and β-lactamases would be helpful to establish network surveillance in order to maintain and control the spread of these resistant strains.

In silico screening of antigenic B-cell derived T-cell epitopes and designing of a multi-epitope peptide vaccine for Acinetobacter nosocomialis

Globally, antibiotic-resistant and tolerated bacterial isolates of Acinetobacter species are imposing high financial cost on health care systems and as such, molecular targets with promising immune protection could provide substantive benefits to human healthcare. Here, we performed an in silico based proteome-wide screening for antigenic B-cell derived T-cell epitopes and their following use to design a multi-epitope peptide vaccine that can effectively engage the host immune system against Acinetobacter nosocomialis SSA3 strain. Epitopes of the fimbrial biogenesis outer membrane usher FimD protein: YQQGINNYL and YRTNYTTVG were revealed appropriate for multi-epitope peptide construct designing. This protein has no homology to the host, essential to the pathogen survival and is localized at the pathogen surface. The predicted epitopes have high affinity for the highly expressed DRB*0101 allele in humans based on the lowest IC50 value in MHCPred and have an exo-membrane topology for efficient immune system recognition. The designed multi-epitope peptide vaccine is composed of the mentioned shortlisted antigenic epitopes linked to each other through a GPGPG linker, and an EAAAK linker that joined the multi-epitope peptide to the Cholera B subunit from Vibrio cholera as an adjuvant to increase vaccine construct antigenicity. The vaccine construct was docked and simulated with a transmembrane toll-like receptor (TLR4) that revealed construct stable binding with the TLR4 through the adjuvant, allowing the epitopes exposed to the host immune system essential for generating effective innate and long-lasting adaptive immunity. The designed multi-epitope peptide vaccine may prompt the development of a vaccine to control refractory and deleterious A. nosocomialis infections.

Prevalence and Resistance Profile of Clinical Isolates of Acinetobacter Species from Karachi, Pakistan

Acinetobacter baumannii causes a variety of infections including pneumonia, urinary tract infection, bacteremia, peritonitis etc. This organism is developing resistance to a number of antibiotics due to various intrinsic and acquired antibiotic resistance genes. The aim of the present study was to determine the prevalence of antibiotic-resistant Acinetobacter species from Karachi, Pakistan. A total of 111 strains of Acinetobacter baumannii and 8 strains of non-baumannii Acinetobacter were isolated from various hospitals of Karachi from September 2013 to December 2014. Identification of the isolates was based on the standard biochemical tests and detection of OXA-51 and OXA-23. Antibiotic resistance profile of the isolates was determined by Kirby-Bauer disc diffusion method and Minimum Inhibitory Concentration (MIC) was also determined by broth macro-dilution method. Among 111 Acinetobacter baumannii isolates, 8 were pan-drug resistant (PDR) and 103 isolates were multidrug resistant (MDR) while all non-baumannii Acinetobacter were MDR. The effective antibiotics against A. baumannii were colistin, gentamicin, trimethoprim/sulfamethoxazole and ciprofloxacin with MIC50 value 1, 256, 256, 256µg/ml, respectively. These findings strongly suggest the proper detection and reporting of PDR/MDR Acinetobacter from clinical samples and also the judicious use of broad-spectrum antibiotics is necessary to prevent the further spread of resistant strains of Acinetobacter.

Biofilm Formation by Acinetobacter Spp. in association with Antibiotic Resistance in clinical samples Obtained from Tertiary Care Hospital

Acinetobacter spp., is an opportunistic, gram negative and non-fermenter organism, has occurred as one of the maximum bothersome pathogens for health care organisations worldwide. This organism generally targets the most susceptible hospitalized patients causing pneumonia mainly in patients on mechanical ventilation in ICU, having urinary tract infection, bloodstream infections, skin infections etc. It accounts for about 10% of all nosocomial infections. Its clinical significance over last 15 years has been forced by its amazing capacity to get resistant elements, making it one of the antagonistic organisms in the current antibiotic era. Most of Acinetobacter strains are resistant to all known antibiotics have been reported and they are acting in interaction with this emerging resistance profile, with this ability. Acinetobacter isolatesare able to survive for long periods throughout the hospital environment.Itrecurrently causes infections associated with medical devices, e.g. vascular catheters, cerebrospinal fluid shunts, urinary catheter or an endotracheal tube. Microbial biofilms are considered as virulence factors and is a well-known pathogenic mechanism in such infections. The ability to form biofilms on biotic or abiotic surfaces is a common trait among Acinetobacter strains. Therefore, the present study was undertaken to study antibiotic resistance patterns and association the resistance profile with bio-film production in various clinical isolates of Acinetobacter spp. A total of 35 isolates of Acinetobacter species were obtained for study from various clinical specimens like pus, urine, sputum, blood culture specimens from the patients admitted in hospital. Isolates obtained from different medical specimens were managed and confirmed by conservative microbiological procedures. The isolates of Acinetobacter are identified on the basis of certain biochemical test like catalase positive, oxidase negative, urease negative, nitrate negative, indole negative and non-motility test. A total of 35 isolates were subjected to susceptibility testing by disc diffusion method according to CLSI guidelines for 14 clinically relevant antibiotics. Screening for biofilm production was done quantitatively by micro titre plate assay method. In the present study, 75 % isolates were showing antibiotic resistance and 22.8% isolates produced bio film along with antibiotic resistance. Biofilm formers isolates showed high resistance to imipenem, cephotaxime, ceftazidime, tobramycin, ciprofloxacin as compared to non-biofilm formers. We selected to study the biofilm formation and antibiotic resistance of clinical isolates of Acinetobacter species to understand its ability to persist in the hospital environment to cause outbreaks.

Biofilm Formation and Colistin Susceptibility of Clinical Isolates of Acinetobacter Species in a Tertiary Care Hospital of Nepal

Biofilm Formation and Colistin Susceptibility of Clinical Isolates of Acinetobacter Species in a Tertiary Care Hospital of Nepal