Acinetobacter Isolates Research Articles

A STUDY OF PREVALENCE AND ANTIMICROBIAL SUSCEPTIBILITY PATTERN OF NON FERMENTER GRAM NEGATIVE BACILLI ISOLATED FROM VARIOUS CLINICAL SAMPLES AT A TERTIARY CARE CENTER, JAIPUR

Introduction: Non-fermentative Gram-negative bacilli (NFGNB) are occasionally involved in infectious diseases pathology, but have shown resistance to multiple antibiotics and the capability to gain new resistance factors in the hospital environment. The present study was aimed to investigate the prevalence of Metallo-beta-lactamase (MBL) producing non-fermenters among the carbapenem-resistant isolates. AMethods: total of 200 NFGNB isolates from various clinical samples were analyzed by using different standard microbiological techniques and antimicrobial susceptibility using Kirby-Bauer method. MBL detection was performed by Modied Hodge test (MHT), imipenem-EDTA combined disc test, and modied Carbapenemase inactivation method (mCIM). In our study, 200 NFGNB isolates recovered from various clinical samples.Results: Pseudomonas aeruginosa was the most common NFGNB, accounting 112 (56%), followed by Acinetobacter baumannii 56 (28%), Burkholderia species 26 (13%) and other rare nonfermenter Gram negative bacilli 6 (3%). NFGNB isolates were maximally isolated from blood samples 73 (36.5%) followed by respiratory samples 46 (23%), urine 40 (20%), pus 37 (18.5%) and CSF 4 (2%). All the NFGNB isolates were susceptible to polymyxin B, colistin (100%), and cefoperazone + sulbactam (45.53%). Out of 112 Pseudomonas isolates, 77(68.75%) were imipenem resistant and of 56 Acinetobacter isolates, 35(62.5%) were imipenem resistant. Out of 77 imipenem resistant Pseudomonas 70 (90.9%) were MBL producers and out of 35 imipinem resistant Acinetobacter spp 32 (91.42%) were MBL producers. NFGNB are now emerging asConclusion: organisms of nosocomial infections. The use of broad-spectrum antibiotics should be avoided and quick detection and efcient infection control measures are essential to prevent the further spread of MBLs to other Gram-negative bacilli. Detection of MBL production and rationale antibiotic usage are the most important factors which control the gradually increasing NFGNB related infections

The susceptibility pattern and distribution of blaOXA-23 genes of clinical isolate Acinetobacter baumannii in a tertiary hospital, Indonesia.

Acinetobacter baumannii, a pathogen of concern in hospitals worldwide, has diverse antimicrobial resistance mechanisms leading to limiting the antibiotic options and carbapenemase enzyme production is one of the common mechanisms in carbapenem resistance. The epidemiology and resistance pattern of clinical isolates are critical in developing a prevention and treatment strategy. The aim of this was to determine the prevalence and resistance pattern of carbapenem non-susceptible strains (CNS) A. baumannii at Arifin Achmad General Hospital, Pekanbaru, Indonesia. Data were retrieved from the culture and susceptibility test results from various clinical specimens from January 2015 to December 2019. A susceptibility test was conducted using Vitek 2 Compact following the manufacturer's protocol. To explore the genetic profile of CNS A. baumannii, we amplified the blaOXA-23 and blaOXA-51 genes, carbapenemase producing genes, using a duplex polymerase chain reaction (PCR) among 24 isolates Chi-squared was used to assess the factors associated with the presence of CNS A. baumannii. Between 2015-2019, 1.263 A. baumannii isolates were tested and the prevalence of CNS A. baumannii was 50%. The trend decreased from 53% in 2016 to 45% in 2019. The proportion of CNS A. baumannii was higher among samples from patients treated in the Intensive Care Unit (ICU) compared to non-ICU (p < 0.001). The CNS A. baumannii was also more frequently detected from sputum than from non-sputum samples (p = 0.009). CNS A. baumannii were highly resistant to almost all antibiotics and the highest susceptibility was to amikacin, tigecycline, and trimethoprim/sulfamethoxazole with 64%, 53%, and 43%, respectively. The blaOXA-23 gene was detected in 92% of tested CNS A. baumannii isolates. The prevalence of CNS A. baumannii is high at Arifin Achmad Hospital Riau, Indonesia. This is also supported by the high prevalence of the blaOXA-23 gene among tested isolates. Based on the antibiotic susceptibility pattern there are limited antibiotic choices for CNS A. baummannii urging the strengthening of antimicrobial stewardship programs in the country.

Outbreak of Pan-resistant Acinetobacter Species in Intensive Care Units of a tertiary care hospital

Background: Acinetobacter has gained significant importance in the medical literature due to the steady development of drug resistance since1980s. Aim: To investigate various patterns and susceptibility trends of the Acinetobacter bacteria isolated from the patients of Intensive Care Units in Holy Family Hospital, Rawalpindi. Methods: It was a cross sectional study carried out at Holy Family Hospital, Rawalpindi from January-July 2019 including case data from intensive care units of medical, surgical, burn and pediatric departments. Acinetobacter isolates were cultured from intensive care units. Antibiotic susceptibility testing was performed using disc diffusion method. Atotal 204 cases of Acinetobacter infection were isolated, of these 102 isolates were from intensive care unit. Majority of the cases were males (56.9%). Results: Our results validate that intensive care units are the main source of overall hospital acquired infections such as Acinetobacter baumanni as half of our cases were isolated in ICUs compared to half in all other general departments. Acinetobacterwas the most common bacterial pathogen 141 (69.1%) isolated in this study followed by klebsiella spp. 32 (15.7%) and e-coli 15 (7.4%). Acinobacter was found to be pan-resistant in more than 80% of the cases. Campylobacter showed frequent resistance to the drug TZP (85%) followed by CAZ (67.6%), SCF (66.2%) and CRO (60.3%). Conclusion: Pan-resistance to Acinetobacter can be associated to the misuse of antibiotics and environmental contamination of hospital equipment and hence it can be implied that these factors play a major role in the outbreaks of Acinetobacter spp. Keywords: Pan-resistance, Acinetobacter, Intensive Care Unit, Hospital Acquired Infections

Catheter-associated urinary tract infections in adult intensive care units at a selected tertiary hospital, Addis Ababa, Ethiopia.

BackgroundCatheter-associated urinary tract infection is the leading cause of hospital-acquired infections. They remain the second most common healthcare-associated infection in critically sick patients.ObjectiveTo determine the prevalence of catheter-associated urinary tract infection, the spectrum of etiological agents, antibiotic sensitivity profile of bacterial pathogens among adult patients admitted to intensive care units.Materials and methodsPatients admitted to the intensive care unit of hospitals in Addis Ababa who were on urethral indwelling catheters for >48 hours from October 2020 to September 2021 were included in the study. Urine specimens were aseptically collected and processed as per standard protocols. Microorganisms were isolated, identified, and subjected to antibiotic susceptibility testing.ResultsIn all 220 pateints included in the study development of significant bacteriuria/candiduria was not affected by sex, age, and prior antibiotic therapy. However, the length of stay in the intensive care unit was significantly associated with bacteriuria /candiduria (P-value < 0.001). The overall prevalence of bacteriuria/candiduria was 51.4% among which 21.0%, 19.1%, and 11.4% were bacteriuria, candiduria, and polymicrobial infections, respectively. About 138 organisms were recovered of which 79 (57.25%) were bacteria and 59 (42.75%) were yeast isolates. Acinetobacter species, Pseudomonas species, Klebsiella species E. coli, and Enterococcus species were the dominant bacterial isolates. Candida. albicans, Candida. krusei and Candida. tropicalis were the commonest yeasts. Many gram-negative bacterial isolates were resistant to ceftriaxone 36(94.7%), ampicillin 21(91.3%) followed by cefotaxime34(89.5%), amikacin (16.0%), nitrofurantoin (17.4%), meropenem (20.0%) and imipenem (20.0%). Out of 79 bacterial pathogens, 52(65.8%) were multiple antibiotic resistant of which 37(71.0%) were Gram-negative bacteria and 15(29%%) were Gram-positive bacteria. About 13(86.7%) isolates of Acinetobacter, all isolates of Klebsiella species (100%) and E. coli (100%) were multiple antibiotic-resistant. Out Of 18,10(55.56%), isolates of Enterococcus were multiple antibiotic-resistant.ConclusionsA very high prevalence of bacteriuria/ candiduria was demonstrated in this study. This warrants the establishment of multidimensional infection control approach on catheter associated urinary tract infection in ICU. In addition to high prevalence of candiduria, recovery of non-albicans candida species almost in equal proportion with candida albicans in the present study was an important finding as non-albicans candida species distinct to C. albicans are intrinsically resistant to the commonly used azole antifungal drugs in Ethiopia. The prevalence of rate MDR bacteria in our ICU particularly of E. coli, Klebsiella spp, Pseudomonas and Acetobacter spp was very high. In order to combat this problem, proper antibiotic policies should be formulated.

The influence of culture-dependent native microbiota in Zika virus infection in Aedes aegypti

BackgroundEmerging and re-emerging vector-borne diseases (VBDs) pose a recurring threat to tropical countries, mainly due to the abundance and distribution of the Aedes aegypti mosquito, which is a vector of the Zika, dengue, chikungunya, and yellow fever arboviruses.MethodsFemale 3–5 day-old Ae. aegypti were distributed into two experimental groups: group I—survey of cultivable bacteria; sucrose group: fed only on sucrose, i.e., non-blood-fed (UF); blood-fed group: (i) fed with non-infected blood (BF); (ii) fed with blood infected with the Zika virus (BZIKV); (iii) pretreated with penicillin/streptomycin (pen/strep), and fed with non-infected blood (TBF); (iv) pretreated with pen/strep and fed blood infected with ZIKV, i.e., gravid with developed ovaries, (TGZIKV); group II—experimental co-infections: bacteria genera isolated from the group fed on sucrose, i.e., non-blood-fed (UF).ResultsUsing the cultivable method and the same mosquito colony and ZIKV strain described by in a previous work, our results reveled 11 isolates (Acinetobacter, Aeromonas, Cedecea, Cellulosimicrobium, Elizabethkingia, Enterobacter, Lysinibacillus, Pantoea, Pseudomonas, Serratia, and Staphylococcus). Enterobacter was present in all evaluated groups (i.e., UF, BF, BZIKV, TBF, and TGZIKV), whereas Elizabethkingia was present in the UF, BZIKV, and TBF groups. Pseudomonas was present in the BZIKV and TBF groups, whereas Staphylococcus was present in the TBF and TGZIKV groups. The only genera of bacteria that were found to be present in only one group were Aeromonas, Lysinibacillus, and Serratia (UF); Cedacea, Pantoea and Acinetobacter (BF); and Cellulosimicrobium (BZIKV). The mosquitoes co-infected with ZIKV plus the isolates group fed on sucrose (UF) showed interference in the outcome of infection.ConclusionsWe demonstrate that the distinct feeding aspects assessed herein influence the composition of bacterial diversity. In the co-infection, among ZIKV, Ae. aegypti and the bacterial isolates, the ZIKV/Lysinibacillus–Ae. aegypti had the lowest number of viral copies in the head-SG, which means that it negatively affects vector competence. However, when the saliva was analyzed after forced feeding, no virus was detected in the mosquito groups ZIKV/Lysinibacillus–Lu. longipalpis and Ae. aegypti; the combination of ZIKV/Serratia may interfere in salivation. This indicates that the combinations do not produce viable viruses and may have great potential as a method of biological control.Graphical

Characterization of carbapenem resistance in environmental samples and Acinetobacter spp. isolates from wastewater and river water in Poland

The aim of this study was to analyze the prevalence of carbapenem resistance genes in Acinetobacter spp. isolated from wastewater in a municipal WWTP and to determine their spread from treated wastewater to river water with the use of conventional and molecular microbiology methods (qualitative and quantitative PCR and metagenomic analysis). Samples of untreated and treated wastewater and samples of river water obtained upstream and downstream from the wastewater discharge point were collected in 3 seasons (February, June, and September) of 2019. Acinetobacter spp. isolates were obtained by the culture method on the CHROMagar™ Acinetobacter medium. Additionally, environmental DNA was extracted from the samples for metagenomic and qPCR analyses. The presence of beta-lactam resistance genes (Ambler class B and D), insertion sequence ISAba1, and class I, II, and III integron-integrase genes was determined, and the bacterial taxonomic structure and wastewater and river samples was analyzed. Out of the 301 isolates obtained on the CHROMagar™ Acinetobacter medium, 258 belonged to the genus Acinetobacter, including 21 isolates that were identified as Acinetobacter baumannii. The highest number of Acinetobacter spp. and A. baumannii isolates were obtained from wastewater and river water samples collected in June and September. The ISAba1/blaOXA-51 complex was identified in 13 isolates, which confirms the occurrence of carbapenem-resistance isolates in the analyzed samples. The number of Acinetobacter isolates carrying antibiotic resistance genes (ARGs) increased in river water samples collected downstream from the wastewater discharge point (48 out of 258 isolates – 18.6%) compared to river water samples collected upstream from the wastewater discharge point (34 out of 258 isolates – 13.2%), which suggests that WWTP is a source of pollution in the natural environment. The conducted research provides evidence that bacteria of the genus Acinetobacter may spread alarming beta-lactam resistance in the environment and, therefore, pose a serious epidemiological threat.

Sulbactam and Colistin Susceptibility Pattern Among Multidrug-Resistant Acinetobacter Isolates From Respiratory Samples

BackgroundAcinetobacter species are known to be important hospital-acquired pathogens. Unfortunately, multidrug-resistant Acinetobacter spp. has very limited options for an effective treatment.AimTo identify the common pathogens causing lower respiratory tract infections (LRTI), their antimicrobial susceptibility pattern, and determine the minimum inhibitory concentration (MIC) of sulbactam and colistin for Acinetobacter spp.Materials and methodsA prospective study was done for a period of six months in a tertiary care hospital in Eastern India. The organisms causing LRTI were identified by conventional biochemical techniques and VITEK 2 Compact System (bioMérieux Inc., France). Antimicrobial susceptibility testing was performed using the Kirby‑Bauer disc diffusion method. MIC was also measured for Acinetobacter spp. to confirm certain antimicrobial agents using E-strips and micro broth dilution techniques.ResultsA total of 542 sputum and endotracheal tube aspirate (ETA) samples were examined during the study period. Among these, 109 samples showed growth of significant colony count of one or two organisms, yielding a sum of 115 isolates. Among these, there were 51 (44.35%) isolates of Klebsiella pneumoniae, 32 (27.83%) isolates of Pseudomonas spp., 30 (26.09%) isolates of Acinetobacter spp., and two (1.74%) isolates of Stenotrophomonas maltophilia. Although they were susceptible to colistin, Acinetobacter spp. was highly resistant to sulbactam.ConclusionAlthough colistin susceptibility was noted, the common pathogens causing LRTI were highly resistant to most drugs. Therefore, the causative organisms of LRTI and their susceptibility pattern should be determined to manage these cases effectively.

Clinical Isolates of Acinetobacter spp. Are Highly Serum Resistant Despite Efficient Recognition by the Complement System.

Gram-negative bacteria from the genus Acinetobacter are responsible for life-threating hospital-related infections such as pneumonia, septicemia, and meningitis, especially in immunocompromised patients. Worryingly, Acinetobacter have become multi- and extensively drug resistant (MDR/XDR) over the last few decades. The complement system is the first line of defense against microbes, thus it is highly important to increase our understanding of evasion mechanisms used by Acinetobacter spp. Here, we studied clinical isolates of Acinetobacter spp. (n=50), aiming to characterize their recognition by the complement system. Most isolates tested survived 1 h incubation in 30% serum, and only 8 isolates had a lower survival rate, yet none of those isolates were fully killed. Intriguingly, four isolates survived in human whole blood containing all cell component. Their survival was, however, significantly reduced. Flow cytometry analyses revealed that most of the isolates were detected by human IgG and IgM. Interestingly, we could not detect any significant concentration of deposited C1q, despite observing C4b deposition that was abolished in C1q-deficient serum, indicating transient binding of C1q to bacteria. Moreover, several isolates were recognized by MBL, with C4b deposition abolished in MBL-deficient serum. C3b was deposited on most isolates, but this was not, however, seen with respect to C5b and formation of the membrane attack complex (MAC), indicating that many isolates could avoid complement-mediated lysis. India ink staining showed that isolates were capsulated, and capsule thickness varied significantly between isolates. Studies performed on a wild-type strain and capsule mutant strains, demonstrated that the production of a capsular polysaccharide is one mechanism that mediates resistance to complement-mediated bactericidal activity by preventing MAC deposition and lysis. Our data showed that most clinical Acinetobacter spp. isolates are highly serum resistant despite being efficiently recognized by the complement system.

Determination of In vitro Antimicrobial activity of copper on the clinical isolates of Acinetobacter spp

Background: Acinetobacter spp., emerging pathogens equipped with the competence to establish multitudinous severe infections in immunocompromised hosts, are grievous threats to human health. To tackle the enormous burden of disease caused by Acinetobacter spp., the headlong discovery and the advancement of novel therapies are of the essence at this juncture. The present study attempted to determine the antimicrobial effects of copper on the clinical isolates of Acinetobacter spp. (Iso-03 and Iso-04). Methods: The potential deployment of copper-based antibacterial strategies against Acinetobacter spp. was assessed by exposing the isolates to the increasing concentrations of CuSO4 (from 2.5 to 1.5 mM) in liquid culture (M9 minimal medium) for 6 h and also through the exposure of them on solid metal surfaces (stainless steel and copper coupons) for 75 min, wherein the copper sensitivity and resistance of the clinical isolates of Acinetobacter spp. were determined. Results: There was no interference with the growth of the isolates at the low concentrations, whereas the bacterial growth was affected by the high concentrations of CuSO4 at different levels. During the exposure on the solid metal coupons, no loss of viability of isolates was observed on stainless steel, however, the rapid death of isolates was discernible on copper surface, leading to a dramatic decrease in the number of colony-forming units (CFUs), eventually to the limit of detection (3 CFUs per coupon). Conclusion: This study substantiated that copper possesses antimicrobial properties which can be deployed in novel therapies for the prevention of the infections caused by Acinetobacter spp. and other emerging pathogens. Further studies on the sensitivity and resistance of Acinetobacter spp. to copper at the molecular genetics levels can open the door to better exploitation of this metal for the inhibition of the vigorous growth of drug-resistant Acinetobacter spp.

Statistical optimization of lipase production from oil mill effluent by Acinetobacter sp. KSPE71

The present study investigated the valorisation of oil-rich residues of coconut oil mill effluent (COME) as a potential growth medium for the microbial production of extracellular lipase. The bacterial species isolated from oil mill effluent, Acinetobacter sp. KSPE71 was tested for its efficiency to grow and produce lipase in undiluted COME and 0.2 % yeast extract and 0.2 % NH4Cl supplemented COME. In this connection, the process parameters such as pH, temperature, agitation speed, and inoculum size were optimized to maximize the production using a central composite design in the Response surface methodology. At the optimized state of pH 7.5, 35?C, 150 rpm with 0.6 % inoculum size, a maximum of 3.95 U mL-1 activity was obtained, four-fold higher than the basal condition. At this stage, 73 % of the lipid content was degraded. The present work results imply that the oil mill effluent can be used as a cheaper production medium for lipase and the new isolate Acinetobacter sp. KSPE71 as a potential lipase producer. The degradation of oil waste along with the production of the valuable product has multiple advantages of cost reduction of lipase and environmental concern.

Antibiotic Resistance Pattern and Prevalence of blaOXA-51, blaNDM, blaVIM, blaPER, blaVEB, blaCTX, tetA and tetB Genes in Acinetobacter baumannii Isolated from Clinical Specimens of Hospitals in Tabriz city, Iran

Background: Nowadays, the resistance of pathogenic bacteria to antibiotics has become a global problem. Acinetobacter baumannii is an important opportunistic nosocomial pathogen. Acinetobacter baumannii plays a significant role in antibiotic resistance. Objectives: The purpose of this study was to investigate the prevalence of the blaOXA-51, blaNDM, blaVIM, blaPER, blaVEB, blaCTX-M, tetA and tetB genes and antibiotic resistance pattern of A. baumannii isolated from hospitals in Tabriz city, Iran. Methods: This study was descriptive cross-sectional research, performed on 129 isolates of Acinetobacter from different clinical specimens. The Isolates were identified using standard laboratory methods and culture in selective mediums. The antibiotic resistance pattern of isolates was also determined by the Kirby-Bauer disk diffusion susceptibility test. Phenotypic and genotypic detection of blaOXA-51, blaNDM, blaVIM, blaPER, blaVEB, blaCTX-M, tetA and tetB genes in the isolates was carried out by a combined disk test (CDT) and polymerase chain reaction (PCR), respectively. Results: The highest resistance of isolates was determined to cefotaxime (100%) and ceftazidime (100%). The results of CDT showed that 14 (12.96%) isolates could produce extended-spectrum Beta-lactamases (ESBLs). However, the PCR results blaOXA-51, blaNDM, blaVIM, blaPER, blaVEB, blaCTX-M, tetA and tetB genes showed that these genes were in 100%, 18.51%, 16.66%, 32.40%, 16.66%, 31.48%, 32.40% and 21.29% of isolates, respectively. Conclusions: Due to the high prevalence of antimicrobial resistance in strains, rapid and timely detection of antibiotic-resistant A. baumannii strains is necessary for the selection of an appropriate therapeutic approach and prevention of their prevalence.

Antimicrobial and Anti-Biofilm Activity of Polymyxin E Alone and in Combination with Probiotic Strains of Bacillus subtilis KATMIRA1933 and Bacillus amyloliquefaciens B-1895 against Clinical Isolates of Selected Acinetobacter spp.: A Preliminary Study.

Acinetobacter spp., the nosocomial pathogen, forms strong biofilms and is resistant to numerous antibiotics, causing persistent infections. This study investigates the antibacterial and anti-biofilm activity of polymyxin E alone and in combination with the cell-free supernatants (CFS) of the tested probiotic bacilli, Bacillus subtilis KATMIRA1933 and Bacillus amyloliquefaciens B-1895 against the selected Acinetobacter spp. starins. Three isolates of Acinetobacter spp., designated as Acinetobacter spp. isolate 1; Acinetobacter spp. isolate 2, and Acinetobacter spp. isolate 3, were collected from patients with burns, wounds, and blood infections, respectively. Bacterial identification and antibiotic susceptibility testing were conducted using the VITEK2 system. Auto-aggregation and coaggregation of the tested bacilli strains with the selected Acinetobacter spp. isolates were evaluated. A disk diffusion assay was used to identify the microorganism’s susceptibility to the selected antibiotics, alone and in combination with the CFS of the bacilli. The MIC and MBIC (minimum inhibitory and minimum biofilm inhibitory concentrations) of polymyxin E combined with bacilli CFS were determined. Acinetobacter spp. isolates were (i) sensitive to polymyxin E, (ii) able to form a strong biofilm, and (iii) resistant to the tested antibiotics and the CFS of tested bacilli. Significant inhibition of biofilm formation was noticed when CFS of the tested bacilli were combined with polymyxin E. The bacilli CFS showed synergy with polymyxin E against planktonic cells and biofilms of the isolated pathogens.

HOSPITAL-ACQUIRED MRSA SEPSIS IN BURN CARE UNIT OF A TERTIARY CARE CENTER IN NORTH INDIA.

INTRODUCTION: Bloodstream infection and the subsequent development of sepsis are among the most common infection complications occurring in burn patients. Hospital-Acquired transmission of microorganisms are associated with the emergence of antimicrobial resistance among a variety of bacterial and fungal burn wound pathogens which limits the therapeutic options for the treatment of infections associated with burns. Over the last several decades, antibiotic resistant organisms have resulted in increased mortality in burns patients. MATERIAL AND METHODS: This prospective study was conducted in the Department of Microbiology, Government Medical College, over a period of 1 year The patients admitted to burn care unit with the following criteria were included in the study: No infection at the time of admission and up to 48 hrs (cultures negative); Length of stay in the hospital more than 48 hrs; Signs and symptoms suggestive of infection. Patients referred from other hospitals were excluded. Samples from patients falling under the inclusion criteria of the study and manifesting any symptoms and signs of Hospital-Acquired infection during the management of burns were included in the study H. ospital-Acquired infections were dened based on CDC criteria as described below: Blood samples for culture were collected from patients with burn wounds showing signs of infection as dened by CDC. Positive Isolates were conrmed by conventional biochemical tests. Isolates exhibiting ambiguous taxonomic classication were conrmed by Vitek-2 Compact Automated Identication System following the manufacturer's instructions. Antimicrobial susceptibility testing were performed using the Kirby-Bauer disk diffusion method according to Clinical and Laboratory Standards Institute (CLSI). OBSERVATIONS AND RESULTS: A total 71 patients developed Hospital-Acquired infections out of these 20 % developed blood stream infection. Most common age group in our study was between 31-40 years (33.80%) Most frequent organisms isolated from blood culture were MRSA (20%) followed by pseudomonas aeruginosa (15%) and Acinetobacter spp (10%).Candida spp was isolated from 10% of cultures. All isolates of stayphlococcus aureus were Methicillin resistant however all ve isolates were sensitive to vancomycin, clindamycin and linezolid. All isolates of Pseudomonas were sensitive to polymyxin-b,while as 33% were sensitive to Gentamicin. All isolates of Acinetobacter were sensitive to Gentamicin and Tobramycin while as only 50% were sensitive to Ooxacin. Further burn units are CONCLUSION: ideal for outbreaks of MDR pathogens which can affect other patients, so adequate infection control measures need to be in place. Culture and antimicrobial susceptibility testing should be performed routinely, including MRSA and ESBL screening, whenever burn wound and blood stream infections are suspected. Antimicrobial sensitivity test results should be used to guide the choice of antibiotics. Also we need to conduct molecular studies on the isolates to determine their resistance genes and strains typing to determine which strains are implicated in these hospital acquired infections.

Nitrate removal from a nitrate-rich reverse osmosis concentrate: Superior efficiency using the bioaugmentation of an Acinetobacter biofilm

Highly effective nitrate removal from a nitrate-rich reverse osmosis (RO) concentrate was achieved by the bioaugmentation of a new Acinetobacter isolate. The anoxic denitrifying capabilities of the isolate were studied in a real RO concentrate solution (containing 230 mg/L nitrate, 14,120 mg/L total dissolved solids, and 18 mg/L biological oxygen demand) obtained from a brackish, nitrate-rich groundwater desalination facility. The treatment of the real RO concentrate with a biofilm afforded a nitrate removal efficiency up to four times greater than that of a bioaugmented bacterial suspension of the Acinetobacter isolate in both batch and continuous bioreactors (nitrate removal rates: 1.34 and 1.37 kg-N/m3•d, respectively). These values are the highest rates of groundwater and groundwater RO concentrate denitrification ever reported. Additionally, the developed method provides the highest denitrification ratio (C:N = 3:1) between biological nitrate assimilation and denitrification. Lastly, both the isolate suspension and the biofilm cultures were able to consume all the organic matter supplemented to the concentrate, which is important since that the organic matter must be removed prior to chlorination and release. This bacterium, therefore, has great potential for successful nitrate removal during RO concentrate treatment.

Microbiological and Antimicrobial Pattern of Diabetic Foot Ulcers at a Tertiary Care Center in East China.

Diabetic foot infections (DFIs) are the most complex and challenging pathological state, characterized by high complexity of management, morbidity, and mortality. Empirical antimicrobial administration is needed before the identification of the causative organisms. Microbiological profile of the diabetic foot patients is the basis of the antibiotic choice for clinicians. 76 patients visiting the Diabetic Foot Center of our Hospital for having ulcers with Wagner 3 to 5 were retrospectively surveyed for the bacterium infected. Antimicrobial susceptibility testing (AST) was implemented and the results were interpreted on the basis of the Clinical and Laboratory Standards Institute (CLSI) guidelines. A total of 92 isolates were obtained, of which 47 strains of gram-negative bacilli (GNB) accounted for 51.1%, 41 strains of gram-positive cocci (GPC) accounted for 44.6%, and 4 strains of fungi accounted for 4.3%. Species of Enterobacteriaceae and Staphylococcus are the two predominant strains. The top 4 most frequently isolated strains were Staphylococcus aureus (22.8%), enterococcus faecalis (9.8%), Pseudomonas aeruginosa (9.8%), Escherichia coli (5.4%). The rate of resistance to methicillin was 33.3% for S. aureus. The rate of extended-spectrum β-lactamases (ESBLs) production among E. coli was 60%. 50% of Klebsiella pneumoniae were resistant to carbapenems. P. aeruginosa showed high sensitivity to commonly used antibiotics. There was one isolate of Acinetobacter spp. resistant to most antimicrobials except tigecycline and aminoglycosides. Enterobacteriaceae and Staphylococcus are the two predominant species. The resistance to antibiotics of S. aureus and P. aeruginosa showed optimistic results. However, the high prevalence of CRKP imposed a challenging issue for clinical physicians.

Isolation, purification and characterization of mannan degrading enzyme from a new isolate Acinetobacter baummanni

A mannan-degrading microbe was isolated from rotting porang tubers (Amorphophallus muelleri Blume). Molecular identification using 16S-rRNA sequence analysis revealed that the isolate showed 99.67% similarity with Acinetobacter baummanni. A crude enzyme from ammonium sulphate precipitation was used for preliminary characterization. The characterization results showed that the enzyme activity is optimum at 45 °C, and stable at 35-50 °C, while the optimum pH is 7, and stable at pH 5-7. The substrate with the highest relative activity was found in guar gum which was 137.512%. The enzyme activity was inhibited by Ca, Na, K ions, and increased by Mn2+ ions.

A comparative study on the performance of microbial fuel cell for the treatment of reactive orange 16 dye using mixed and pure bacterial species and its optimization using response surface methodology

The present work provides an insight on the removal of dye and energy recovery simultaneously by Acinetobacter pitii in microbial fuel cells. It focuses on decolorization of reactive orange 16 dye and electricity production in a microbial fuel cell using bacterial isolate Acinetobacter pitii. This isolate removes 92.70% of color at a fixed concentration of 500 ppm of dye within 24 h on the 20th day of operation. The maximum voltage and current density obtained from the species is found to be 0.4379 V and 0.973 A/m3 at 1000 Ω. The central composite design was used to model the process for the removal of 243 ppm of dye from the initial dye concentration of 295 ppm at pH of 7.5, time 71.27 h, with simultaneous production of 1.06 A/m3 of current density. Analytical techniques such as Chemical Oxygen Demand (COD), Fourier-transform infrared spectroscopy (FTIR), Liquid chromatography and mass spectroscopy analysis (LCMS), Scanning electron microscope (SEM), and carbon-di-oxide (CO2) determination were used to study about the nature of the removal of reactive orange 16 dye in a microbial fuel cell. The toxicity of the degraded sample was assessed using Phytotoxicity analysis.

Quorum sensing disruption regulates hydrolytic enzyme and biofilm production in estuarine bacteria.

Biofilms of heterotrophic bacteria cover organic matter aggregates and constitute hotspots of mineralization, primarily acting through extracellular hydrolytic enzyme production. Nevertheless, regulation of both biofilm and hydrolytic enzyme synthesis remains poorly investigated, especially in estuarine ecosystems. In this study, various bioassays, mass spectrometry and genomics approaches were combined to test the possible involvement of quorum sensing (QS) in these mechanisms. QS is a bacterial cell-cell communication system that relies notably on the emission of N-acylhomoserine lactones (AHLs). In our estuarine bacterial collection, we found that 28 strains (9%), mainly Vibrio, Pseudomonas and Acinetobacter isolates, produced at least 14 different types of AHLs encoded by various luxI genes. We then inhibited the AHL QS circuits of those 28 strains using a broad-spectrum lactonase preparation and tested whether biofilm production as well as β-glucosidase and leucine-aminopeptidase activities were impacted. Interestingly, we recorded contrasted responses, as biofilm production, dissolved and cell-bound β-glucosidase and leucine-aminopeptidase activities significantly increased in 4%-68% of strains but decreased in 0%-21% of strains. These findings highlight the key role of AHL-based QS in estuarine bacterial physiology and ultimately on biogeochemical cycles. They also point out the complexity of QS regulations within natural microbial assemblages.

PHENOTYPIC DETECTION OF EFFLUX MECHANISM IN AMIKACIN-RESISTANT ACINETOBACTER ISOLATES FROM TWO DIFFERENT STATES IN SOUTH INDIA

Acinetobacter has already gained resistance to the majority of antibiotics available. Aminoglycosides are commonly used to treat invasive infections. Aminoglycoside resistance is associated with decreased drug absorption, aminoglycoside modification, and aminoglycoside efflux. The aim of this study was to detect the presence of an efflux mechanism in amikacin-resistant Acinetobacter isolated from hospital wards using Carbonyl Cyanide 3- Chlorophenylhydrazone (CCCP). One hundred isolates of Acinetobacter were isolated from tertiary care hospitals in two distinct South Indian states. Antibacterial susceptibility patterns were discovered between 2017 and 2019. Amikacin minimum inhibitory concentration (MIC) for resistant Acinetobacter isolates was determined using Clinical and Laboratory Standards Institute (CLSI) standards. The efflux system activity was determined using CCCP. Among 100 Acinetobacter baumannii isolates, 49 isolates with amikacin resistance were found. The MIC’s of Acinetobacter ranged between 2 – 1024 μg/mL for the amikacin studied. After treatment with the efflux pump inhibitor, 38.77% of isolates became less resistant to amikacin, as determined by phenotypic detection of efflux pumps, showing a decrease in antibiotic MICs of at least four fold. The data demonstrated the importance of efflux pump activity conferring amikacin resistance on Acinetobacter clinical isolates.

Biosafety assessment of Acinetobacter strains isolated from the Three Gorges Reservoir region in nematode Caenorhabditis elegans

Acinetobacter has been frequently detected in backwater areas of the Three Gorges Reservoir (TGR) region. We here employed Caenorhabditis elegans to perform biosafety assessment of Acinetobacter strains isolated from backwater area in the TGR region. Among 21 isolates and 5 reference strains of Acinetobacter, exposure to Acinetobacter strains of AC1, AC15, AC18, AC21, A. baumannii ATCC 19606T, A. junii NH88-14, and A. lwoffii DSM 2403T resulted in significant decrease in locomotion behavior and reduction in lifespan of Caenorhabditis elegans. In nematodes, exposure to Acinetobacter strains of AC1, AC15, AC18, AC21, A. baumannii, A. junii and A. lwoffii also resulted in significant reactive oxygen species (ROS) production. Moreover, exposure to Acinetobacter isolates of AC1, AC15, AC18, and AC21 led to significant increase in expressions of both SOD-3::GFP and some antimicrobial genes (lys-1, spp-12, lys-7, dod-6, spp-1, dod-22, lys-8, and/or F55G11.4) in nematodes. The Acinetobacter isolates of AC1, AC15, AC18, and AC21 had different morphological, biochemical, phylogenetical, and virulence gene properties. Our results suggested that exposure risk of some Acinetobacter strains isolated from the TGR region exists for environmental organisms and human health. In addition, C. elegans is useful to assess biosafety of Acinetobacter isolates from the environment.