Resistant Bacilli Research Articles

Application progress of polymyxin in bloodstream infection of drug-resistant Acinetobacter baumannii

In recent years, the bloodstream infection rate of Gram-negative bacilli has continued to increase. Among them, drug-resistant bacteria have a higher mortality rate and longer hospital stay, especially the bloodstream infection of carbapenem-resistant Acinetobacter baumannii (CRAB). Polymyxin began to be used clinically in the 1950s and has antibacterial activity against multidrug resistant and poly drug-resistant Gram-negative bacilli. It can also be used as an effective permeation agent for the cell envelope of Gram-negative bacilli. Polymyxin is reserved for microbiologically clear drug-resistant Gram-negative bacilli infections. The World Health Organization classifies polymyxin as an antimicrobial drug with clinical significance for human infections and can be used to treat drug-resistant Acinetobacter baumannii infection. This article reviews the clinical treatment of polymyxin in bloodstream infections of drug-resistant Acinetobacter baumannii, to provide reference for clinical medication.

Efficacy Assessment of High Dose Colistin against Carbapenem-Resistant Gram-Negative Bacteria (CR-GNB) in Critically Ill Patients: A Retrospective Non-Inferiority Trial

Background: Colistin is an effective treatment option, recommended for carbapenem resistant gram-negative bacilli (CR-GNB) in critically ill patients. Due to high nephrotoxicity, dose management of Colistin is a tough decision to make. At standard dosage the efficacy of Colistin is not well defined. Consequently, strategies involving higher dosages were suggested. Objective: To evaluate the high dose of Colistin as non-inferior to standard dose in the treatment of CR-GNB in critically ill patients. Study Design: Retrospective comparative study Place and Duration of Study: Intensive Care Unit, King Saud Medical City Riyadh, Saudi Arabia from 1st January 2015 to 31st December 2017. Methodology: One hundred and ninety two patients that met the inclusion criteria from all participants were further divided into two groups. Group H (High dose) given the high dose of Colistin (9 million units intravenously (IV) loading dose, and then 9 million units/day in 2 or three divided doses) whereas group S was administered with standard dose (no loading dose, 6 million units/day). The primary endpoint of the study was the assessment of nephrotoxicity after the start of Colistin and secondary endpoints were the mortality within 14 days of commencing Colistin along with clinical effects and microbial clearance upon completion of treatment. Results: The results of the study established the non-inferiority of high dose of Colistin for the renal safety and also showed significant improvement in microbial clearance and length of ICU stay as compared to the standard dose. The other secondary end points such as mortality (p = 0.99), length of hospital stay (p = 0.39), and global improvement (p value of 0.06) revealed no significant difference between the two groups. Conclusion: The high dose of Colistin for the treatment of carbapenem resistance gram negative bacilli (CRGNB) was as safe as the standard dose for renal safety. But we also found that it also accelerates microbial clearance and reduces the time spent in the intensive care unit. Key words: Colistin, Colestimethate sodium, Gram negative bacteraemia, Sepsis, Multi-drug resistant organisms, Acute kidney injury

Carbapenemases produced in Klebsiella spp., and Pseudomonas aeruginosa in six hospitals in Bogotá - Colombia

In the last decades, the prevalence of infections by carbapenem resistant gram-negative bacilli has been increased. To determine types and frequency of the different carbapenemases in Klebsiella spp. and Pseudomonas aeruginosa, in six hospitals in Bogotá-Colombia. Descriptive and observational study, in six hospitals in the city of Bogotá, in the period ftom January 2017 to August 2018. PCR were performed for KPC, GES, VIM, NDM, IMP and OXA-48 genes, in carbapenem resistant Klebsiella spp. and P aeruginosa. 52 P aeruginosa isolates amplified a carbapenemase gene, of which 39 (75%) were positive for KPC, 11 (21%) for VIM and two co-productions of KPC and VIM. Regarding Klebsiella spp. 165 strains amplified at least one carbapenemase gene, 98% expressed KPC and four isolates had co-productions of metallo-P-lactamases and KPC. This study provides valuable information, such as the increased production of KPC in P. aeruginosa información valiosa, como el incremento de producción de KPC en P. aeruginosa and the co-production of KPC plus metallobetalactamases, which has an implication both in treatment selection, isolation precautions and patient prognosisy.

Subinhibitory Levels of Oxytetracycline in Earthworm Meal Significantly Boost Resistance-Mutation Rates in Bacillus spp. within the Gut of Eisenia fetida

Aims: To estimate changes in the number of oxytetracycline -resistant strains, a dynamic population of Bacillus in the gut of Eisenia fetida cultured in processed-cow-dung (PrCD) supplemented with subinhibitory amounts of oxytetracycline, was studied.
 Study Design: Sterile water containing oxytetracycline was sprayed over PrCD at concentration of 0.012 µg per mg dehydrated PrCD per spraying. The number of oxytetracycline-resistant Bacillus spp. microbiota of E. fetida’s gut was compared to the number of oxytetracycline-resistant Bacillus spp. in its feed (PrCD). For this purpose, Luria Agar (LA) and Bacillus Agar (BA) plates amended with or without oxytetracycline were used.
 Place and Duration of Study: The study was carried out in the Omics Laboratory of Department of Biotechnology, University of North Bengal situated in Darjeeling district of West Bengal, India during 2017-18.
 Methodology: E. fetida gut content and PrCD samples were collected on different days of the experiment for bacteriological analysis. Dilution plating on LA yielded the total number of cultivable heterotrophic bacteria. LA plates amended with oxytetracycline (15 µg/ml) were used to acquire the fraction of heterotrophic bacteria resistant to oxytetracycline. BA plates were also utilized to obtain the fraction of resistant Bacillus spp. population. The frequency of mutation was determined using a conventional formula.
 Results: In the gut of E. fetida reared in PrCD supplemented with sub-inhibitory concentration of oxytetracycline, a rise in the oxytetracycline-resistant Bacillus population was observed. On day 1, the frequency of oxytetracycline-resistant Bacillus spp. (5×10-8) matched the spontaneous mutation frequency, however higher frequencies on days 2 and 7 (1.6×10-4 and 3.5 x 10-6 respectively) suggested significant dissemination of oxytetracycline resistance in the gut environment.
 Conclusion: Subinhibitory oxytetracycline concentrations in earthworm diet had a significant effect on mutation rates, showing that evolutionary forces on the gut microbiota may be determining their responses to antibiotic stress.

METTL3-mediated M6A methylation modification is involved in colistin-induced nephrotoxicity through apoptosis mediated by Keap1/Nrf2 signaling pathway

Colistin is a cationic polypeptide antibiotic. Despite its nephrotoxicity, it is still widely used as a last-line antibiotic against infection worldwide with the emergence of multi-drug resistant Gram-negative bacilli. N-methyladenosine (m6A) methylation-mediated degradation of RNA is essential for kidney development. However, m6A methylation impacts not only RNA stability, but also other RNA metabolism processes. How RNA decay affects the nephrotoxicity of colistin is largely unknown. Therefore, in this study, we verified that colistin could induce mouse kidney apoptosis through some apoptotic indicators, and confirmed the relationship between methylation and apoptosis through the detection of m6A methylation, thus elucidating the potential mechanism of colistin nephrotoxicity. The results showed that the renal tubule dilation and tubular structure were observed in the colistin group, and the oxidative stress index and ATPase activities were significantly different from those in the control group. Under electron microscope, the kidney in colistin group showed typical apoptotic morphological changes such as nuclear pyknosis, chromatin edge aggregation, and intact nuclear membrane, accompanied by significant changes in apoptosis-related genes. The level of m6A in the colistin group was significantly decreased, accompanied by downregulation of METTL3 mRNA and protein levels, and METTL3 was significantly correlated with apoptotic gene proteins. Data from this study suggested that m6A methylation was involved in oxidative stress-mediated apoptosis in the mechanism of colistin nephrotoxicity.

Meropenem Resistance among Acinetobacter Positive Clinical Samples in a Tertiary Care Centre in Nepal: A Descriptive Cross-sectional Study.

Antimicrobial-resistant Acinetobacter species are implicated in a variety of infections including nosocomial bacteraemia, secondary meningitis, and urinary tract infections. Carbapenem including meropenem-resistant Acinetobacter is recognized as one of the most difficult antimicrobial resistant gram-negative bacilli to control and treat. It was classified as an urgent threat by Centers for Disease Control and Prevention in 2019 Antibiotic Resistance Threats Report. This study was carried out to determine the prevalence of meropenem resistance among acinetobacter positive clinical samples in a tertiary care centre. A descriptive cross-sectional study was carried out in microbiology department of Clinical Laboratory Services among Acinetobacter positive clinical samples of a tertiary care center in Nepal. The culture and sensitivity reports of various clinical samples from April 2018 to April 2020 which were positive for Acinetobacter species were taken from hospital records section. Convenience sampling was done. Meropenem-resistant Acinetobacter samples were studied. Ethical approval was received from Institutional Review Committee (Ref No. 076/77/40). Analysis of data was done using Statistical Package for the Social Sciences version 26. Point estimate at 95% Confidence Interval calculated with frequency. Out of 121 Acinetobacter isolates, prevalence of meropenem-resistant Acinetobacter was reported in 93 (76.9%) at 95% Confidence Interval (69.39-84.40). Among the meropenem-resistant Acinetobacter samples, most of the samples were collected from the sputum 70 (75.2%) followed by blood 8 (8.6%). High prevalence of meropenem-resistant Acinetobacter species in our hospital setting is alarming. In addition, there is emergence of resistance against even the last resort drugs which is creating a treatment crisis.

Impact of broad-spectrum antibiotic exposures and multidrug-resistant gram-negative bacteremia on hematopoietic cell transplantation outcomes.

There is a close association between the use of broad-spectrum antibiotics, gut microbiome alteration, multidrug resistant (MDR) gram-negative bacilli (GNB) bacteremia, graft versus host disease (GVHD), and mortality post-allogeneic hematopoietic cell transplantation (allo-HCT). This study reports the impact of the high use of carbapenems and colistin and MDR bacteremia pre- and post-HCT on HCT outcomes. This was a single-center, partial retrospective, and prospective study from 2016 to 2020. Both pre- and post-HCT antibiotic exposures and blood culture/sensitivity were recorded. MDR GNB was defined as either non-susceptibility to third-generation cephalosporin or carbapenems. In the absence of positive cultures, the treating physician escalated antibiotics from third-generation cephalosporins to carbapenem and/or colistin as per clinical discretion. De-escalation policy was not strictly enforced. MDR GNB bacteremia was seen in 29 of 76 (38%) of patients peri-HCT. The utilization rates for carbapenems and colistin was significantly higher in the cohort with MDR GNB bacteremia pre-HCT (70%vs. 32%, p=0.002 and 31%vs. 6.4%, p=0.007, respectively) and post-HCT (100%vs. 74.5%, p=0.002, and 55.2%vs. 8.5%, p<0.0001, respectively). The cohort with MDR GNB bacteremia had significantly more severe acute GVHD at day+100 (45%vs. 17.5%, p=0.009). The median survival was 204 days compared to not reached in the cohort without any MDR GNB bacteremia (p=0.005). This study shows pre- and post-HCT MDR GNB bacteremia is associated with an increased risk of severe acute GVHD and mortality. Patients with MDR GNB bacteremia had higher exposure to pre- and post-HCT carbapenems and colistin.

Combined application of two Bacillus species enhance phytoremediation potential of Brassica napus in an industrial metal-contaminated soil

This study aimed to assess the impact of individual as well as combined application of Lysinibacillus macroides and Bacillus safensis in phytoremediation potential of Brassica napus grown in soil contaminated by industrial effluents. In response to five metals; copper, chromium, nickel, lead, and cadmium, results revealed that germination percentage, fresh and dry weights, and photosynthetic pigments of B. napus decreased under contaminated soil. On the other hand, electrolyte leakage due to cellular injury, metabolites (proline and glycine betaine), antioxidant enzymes (superoxide dismutase, catalase, peroxidase, ascorbate peroxidase), accumulation of hydrogen peroxide and metals in plant’s roots, shoots and leaves increased. Inoculation significantly reduced these effects as proved by the enhancement of germination percentage, fresh and dry biomass, and photosynthetic pigments. Simultaneously, the antioxidant enzymes, metabolites contents (proline and glycine betaine) and metal concentrations in plant’s roots, shoots and leaves decreased. Combined application of both Bacilli strains was found more effective as compared to individual inoculation. It was concluded that metal resistant Bacillus species in combination had growth effects on B. napus and enhanced its phytoremediation efficiency in contaminated soil. Novelty statement Brassica napus; a hyper-accumulator of metals, loses phytoremediation potential with the passage of growth. Two Bacillus species (Lysinibacillus macroides and Bacillus safensis) having known bioremediation abilities were employed individually as well as in combination under metals contaminated soil to increase phytoremediation efficiency of B. napus. The metals containing soil used is a unique aspect in this study because selected soil, contaminated by industrial effluents, has not been evaluated or reported earlier. Combined application of Bacilli improved phytoremediation potential of B. napus more as compared to application of individual Bacillus strain which is yet another unique aspect of this investigation.

Effectiveness of a Multicomponent Intervention to Reduce Multidrug-Resistant Organisms in Nursing Homes

Multidrug-resistant organisms (MDROs) can cause significant morbidity and mortality. Preventing MDROs can reduce the risk of subsequent transmission and infection. To determine whether a multicomponent infection prevention intervention can reduce MDRO prevalence in nursing homes (NHs). This cluster randomized clinical trial of a multicomponent intervention was conducted in 6 NHs in Michigan from September 2016 to August 2018. Three NHs adopted a multicomponent intervention, while 3 control NHs continued without investigator intervention. Study visits were conducted at baseline; days 7, 14, 21, and 30; and monthly thereafter for up to 6 months or discharge. Visits included clinical data collection and MDRO surveillance culturing of multiple body sites and high-touch surfaces in patient rooms. Any patients who provided informed consent within 14 days of admission to the NH were enrolled in this study. Non-English speakers and patients receiving hospice care were ineligible. Analysis was performed from November 2018 to February 2020. Intervention NHs adopted a multicomponent intervention that included enhanced barrier precautions, chlorhexidine bathing, MDRO surveillance, environmental cleaning education and feedback, hand hygiene promotion, and health care worker education and feedback. Control nursing homes continued standard care practices. The primary outcome, presence of MDROs, was measured longitudinally in the patient and room environment and was evaluated using generalized mixed effect models. The secondary outcome, time to new MDRO acquisition, was assessed using Cox proportional hazard models. A total of 6 NHs were included, with 245 patients (mean [SD] age, 72.5 [13.6] years; 134 [54.7%] women) enrolled; 3 NHs with 113 patients (46.1%) were randomized to the intervention group and 3 NHs with 132 patients (53.9%) were randomized to the control group. A total of 132 patients (53.9%) were White, and 235 patients (95.9%) were receiving postacute care. Over 808 study visits, 3654 patient cultures and 5606 environmental cultures were obtained. The intervention reduced the odds of MDRO prevalence in patients' environment by 43% (aOR, 0.57; 95% CI, 0.35-0.94), but there was no statistically significant difference on the patient level before or after adjustment (aOR, 0.57; 95% CI, 0.29-1.14). There were no significant reductions in time to new acquisition for methicillin-resistant Staphylococcus aureus (hazard ratio [HR], 0.20; 95% CI, 0.04-1.09), vancomycin-resistant enterococci (HR, 0.84; 95% CI, 0.46-1.53), or resistant gram-negative bacilli (HR, 1.14; 95% CI, 0.73-1.78). This cluster randomized clinical trial found that the multicomponent intervention reduced the prevalence of MDROs in the environment of NH patients. Our findings highlight the potential for multicomponent interventions to directly and indirectly reduce MDRO prevalence in NHs. ClinicalTrials.gov Identifier: NCT02909946.

#3: Gram-Negative Antibacterial Resistance Prevalence at a Tertiary Care Hospital in Central America

Abstract Background Latin America has some of the highest rates of multi-drug resistant gram-negative bacteria worldwide. However, local surveillance registries to compare rates of resistance among countries are lacking, particularly in Central America. Awareness of local resistance patterns in this region is critical to improve antibiotic use and patient outcomes. We sought to measure the prevalence of resistant gram-negative bacilli (GNB) at a tertiary hospital in Guatemala. Methods We retrospectively conducted a single-center study to measure the percentage of GNB that were non-susceptible to various antibiotics between April and October of 2017. All cultures (blood, urine, cerebrospinal fluid, and other body fluids) were collected as part of routine clinical care during the study period. Duplicate isolates, defined as multiple specimens with the same organism from the same patient, were excluded. Antibiotic susceptibility testing was performed by disk diffusion method. Bacterial isolates were categorized as susceptible, intermediate, or resistant based upon the Clinical Laboratory Standard Institute 27th edition per guidance from the National Laboratory of Guatemala. Results A total of 969 unique gram-negative isolates from 818 patients were included. Urine was the most common culture type. The most frequently isolated bacteria were Escherichia coli and Klebsiella species. The percentage of GNB which were non-susceptible to individual antibiotics are detailed in Table 1. Of the isolates tested, 12 – 66% of GNB were non-susceptible to cephalosporins, 7 – 31% were non-susceptible to carbapenems, and 14 – 44% were non-susceptible to fluroquinolones. Conclusions The prevalence of multi-drug resistant GNB is high in Escuintla, Guatemala. Continued surveillance is vital to guide judicious and appropriate empiric antibiotic use in the setting of rising rates of antibiotic resistance. Local and regional resistance rates are known to vary, underlying the importance of developing more regional and national antibiotic resistance surveillance networks within Guatemala and other countries in Central America where there is a paucity of data.

Silver carboxylate and titanium dioxide-polydimethylsiloxane coating decreases adherence of multi-drug resistant Serratia marcescens on spinal implant materials.

The opportunistic multi-drug resistant nosocomial gram negative bacilli Serratia marcescens (S. marcescens) is a rising contributor to spinal implant infections (Iguchi et al., Genome Biol Evol 6:2096-2110, 2014; Teresa et al., J Clin Microbiol 55:2334-2347; Dante et al., J Clin Microbiol 54:120-126). This study investigates the most effective matrix ratio of an antibiotic-independent, silver carboxylate-doped titanium dioxide (TiO2)-polydimethylsiloxane (PDMS) coating in preventing adherence of multidrug resistant pathogen S. marcescens to spinal implant materials. This project examined an antibiotic-independent, silver carboxylate-doped titanium dioxide (TiO2)-polydimethylsiloxane (PDMS) coating on three common spinal implant materials, polyetheretherketone (PEEK), stainless steel (SS), and titanium (Ti), which previously were found to be prone to bacterial adhesion (Garcia et al., Spine Deform 8:351-359). After generation of dose response curves to find the optimal silver carboxylate concentration, 95% TiO2-5% PDMS was combined with 10× silver carboxylate and compared to 100% silver carboxylate and uncoated implants. Implants were imaged using scanning electron microscopy and confocal laser scanning microscopy to detect adherent S. marcescens. Ninety-five percent TiO2-5% PDMS and 10× silver carboxylate coating decreased adherence of S. marcescens on PEEK by 99.61% (p = 0.001), on titanium by 98.77% (p = 0.001), and on stainless steel by 88.10% (p = 0.001) after 24h. The average decrease in bacterial adherence was 95.49% compared to uncoated implants. A coating composition comprised of 95% TiO2-5% PDMS matrix and 10× silver carboxylate most effectively decreases adherence of S. marcescens on spinal implants. These results suggest that the application of a non-antibiotic, bactericidal coating prior to spinal surgery may prevent the adherence and proliferation of MDR S. marcescens and decrease the incidence of spinal SSI.

Re-thinking treatment strategies for febrile neutropenia in paediatric oncology population: the perspective from a developing country

BackgroundThis study was conducted to evaluate the microbiological profile of bacterial isolates in febrile neutropenia in a pediatric oncology unit, thereby, reviewing the use of restricted antibiotics and need for aggressive medical treatment accordingly.MethodsA prospective observational study was conducted in a paediatric haemat-oncology division of a tertiary care teaching hospital in southern India from September 2014 to August 2016. One hundred and thirty children with febrile neutropenia were enrolled in the study. Blood cultures were performed using automated system. Cultures from other sites were obtained if needed, based on the clinical profile. Standard antibiotic susceptibility testing was done. Statistical analysis was done using SPSS.ResultsOne hundred and thirty children were enrolled for the study. Two hundred and fifty episodes of febrile neutropenia were studied. Three hundred and eighty four cultures were sent and 92 (24%) cultures were positive. There were 48 (52.2%) Gram negative isolates followed by 33 (35.8%) Gram positive isolates, six (6.5%) fungal isolates and five (5.5%) poly-microbial cultures. Lactose fermenting Gram negative bacilli (20 isolates, 31.5%) were the most frequently isolated in the Gram negative group, with Escherichia coli being the most common organism (19 isolates, 20.6%). Amongst the Gram positive coagulase negative staphylococcus was the most common (twenty seven isolates, 29%). Escherichia coli and Non lactose fermenting gram negative bacteria (NFGNB) had only 36, 25% sensitivity to ceftazidime, respectively. Most Gram negative bacilli were found to have better sensitivity to amikacin (mean: 57%). There was a higher prevalence of extended spectrum beta lactamase producing organisms. Pan drug resistance, Extreme drug resistance and Multi drug resistance was found in three, twenty and thirteen Gram negative isolates respectively.Escherichia coli and Klebsiella were often drug resistant. Significantly higher mortality was associated with Gram negative isolates (eight deaths out of the thirteen deaths, 61.5%).ConclusionsOur results show the importance of surveillance, monitoring resistance frequencies and identifying risk factors specific to each region. Given that significant mortality is attributed to drug resistant Gram negative bacilli, early initiation of appropriate antibiotics to cover for drug resistance is required while formulating empirical antibiotic policies for febrile neutropenia in the oncology units in the developing world.

Can alternative anatomical sites and environmental surveillance replace perianal screening for multidrug-resistant organisms in nursing homes?

Perianal screening can be intrusive. The sensitivities of multianatomical, nonperianal surveillance were 92.3% for methicillin-resistant Staphylococcus aureus (MRSA), 58.7% for vancomycin-resistant enterococci (VRE), and 54.9% for resistant Gram-negative bacilli (R-GNB). Sensitivities improved upon adding environmental surveillance (95.5%, 82.9%, and 67.9%, respectively). Multianatomical, nonperianal screening and room environment surveillance may replace perianal screening and reduce healthy participant bias in nursing homes.

Multi-Drug Resistant (MDR) and carbapenemase co-producing Gram-negative bacilli in northwest of Iran

Carbapenemase enzymes confer clinically significant resistance to Gram-negative bacteria, only a few antibiotics with adverse side effects and/or unfavorable in vivo efficacy remains. This study sought to determine the prevalence of carbapenemase producing gram-negative organisms and also investigate the antibacterial susceptibility profile of carbapenem-resistant isolates. In this study, over a two-year period (2017–2019) a total of 140 imipenem and/or meropenem resistant gram negative bacilli were collected from various specimens sent to microbiology laboratory of university hospital. Disk diffusion antimicrobial susceptibility test was used to evaluate MDR isolates; also multiplex polymerase chain reaction and sequencing were performed for confirmation of carbapenemase production. In disk diffusion method, all isolates were resistant to cefazolin. High rate of resistance was observed against imipenem (98.6%), followed by cefotaxime (97.1%), trimethoprim-sulfamethoxazole (91.4%). Colistin was found as the most effective agent with only 5.7% of resistance, followed by amikacin. Based on PCR results and subsequent sequencing, 46.4% of the isolates were genetically recognized to be carrying at least one carbapenemase gene. Encoded carbapenemases were OXA-48-like (18.6%), VIM-2 (15%), IMP-1 (9.3%), KPC (5.7%), NDM-1 (3.6%), and AIM-1 (2.1%). All isolates were negative for SIM, BIC, SPM, GIM and DIM enzymes. Five isolates were co-harbored blaVIM-2 and blaOXA-48. Moreover, co-harbored carbapenemase genes were observed in six isolates as 6 two-genes-harbored profiles. Our results indicate a relatively high incidence of carbapenemase genes. In addition, the emergence of isolates harboring multiple carbapenemases is of great concern, since these isolates will result in a broad-spectrum antibiotic resistance. Molecular characterization of carbapenemase producers can be helpful tool to offer an effective treatment policy. The worrisome high rate of antibiotic resistance highlights the necessity of active surveillance to antibiotic prescription and\\or self-medication by patients.

UNPRECEDENTED ANTIMICROBIAL PROPERTIES OF PROSOPIS CINERARIA LEAVES

The antibacterial effect of Prosopis cineraria leaves was evaluated on multidrug resistant (MDR) strains of Bacillus subtilis (ATCC 6633), E. coli (ATCC 8739), Salmonella enterica (ATCC 14028), Staphylococcus aureus (ATCC 6538), Pseudomonas aeruginosa (ATCC 27853). Powdered leaves of the tree were treated with methanol for the extraction. Crude methanol extracts of the leaves of P. cineraria was investigated for their antibacterial activity against a wide range of bacteria (both gram-positive and gram-negative) by agar well diffusion method. Ciprofloxacin was used as standard. The methanolic leaves extracts of P. cineraria showed a remarkable inhibition of the microorganisms. The potency shown by these extracts recommends their use against multidrug resistant microorganisms. The present study suggests that the methanol extract of the leaves of P. cineraria exhibited a potential antibacterial activity against the tested microorganisms and could be a potential source of new antimicrobial agents.

Characterization of multiresistant gram-negative bacilli, isolated in patients hospitalized in health institutions in Barranquilla (Colombia)

The emergence of carbapenem resistant gramnegative bacilli has become a problem of public health worldwide, because it is associated with high mortality rates, increased levels of resistance to other antimicrobials, increased potential for dissemination transition and increase in health care costs. To characterize multiresistant gram-negative bacilli, isolated in patients hospitalized in health institutions of Barranquilla (Colombia). A descriptive study was conducted on the phenotypic and genotypic characterization of bacterial resistance in infections associated with health care, mediated by carbapenemases in bacterial isolates sent by laboratories belonging to the laboratory network of the Department of Atlántico. KPC was the most frequent carbapenemase in Enterobacterales (27.6%), predominantly in Klebsiella pneumoniae (13.1%) alone and associated with other carbapenemases. In Pseudomonas aeruginosa, VIM carbapenemase (32.8%) predominated and OXA in Acinetobacter baumannii (17.1%). A wide distribution of multi-resistant strains producing carbapenemases in Atlantic health institutions was found, which expressed the following resistance mechanisms: KPC, VIM, NDM, OXA.

Characterization of multiple metal resistant Bacillus licheniformis and its potential use in arsenic contaminated industrial wastewater

In the present study, the arsenic bioremediation ability of Bacillus licheniformis (dubbed as A6) was determined. The strain was isolated from metal polluted wastewater and was identified on the basis of 16S rRNA sequence homology with accession number of KX 785,171. The bacterium showed resistance against multiple toxic heavy metals, and MIC against arsenic was 3000 µg/ml. Resistance of the bacterium against other toxic metal ions was 3000 µg/ml (Cr), 50 µg/ml (Hg), 1000 µg/ml (Mn), 4000 µg/ml (Se), 500 µg/ml (Pb), 100 µg/ml (Co), 70 µg/ml (Cd) and 100 µg/ml (Zn). The optimum growth temperature was 37 °C while pH was 7. The strain also showed resistance against commonly used antibiotics except ceftriaxone 30 µg and amoxicillin with clavulanic acid (2:1) 3 µg. B. licheniformis could oxidize arsenite into arsenate 86 and 98% after 48 and 96 h from the medium at optimum growth conditions. Due to its high oxidation potential, B. licheniformis can be used in the biological treatment of wastewater containing arsenic.

Risk Factors for Mortality in Hematopoietic Stem Cell Transplantation Recipients with Bloodstream Infection: Points To Be Addressed by Future Guidelines

In recent years, important epidemiologic changes have been described in hematopoietic stem cell transplantation (HSCT) recipients with bloodstream infection (BSI), with increases in gram-negative bacilli and multidrug resistant (MDR) gram-negative bacilli. These changes have been linked to a worrisome increase in mortality. We aimed to define the risk factors for mortality of HSCT patients experiencing BSI. All episodes of BSI in patients with HSCT between 2008 and 2017 were prospectively collected. Multivariate analyses were performed. A total of 402 BSI episodes were documented in 293 patients who had undergone HSCT (75.4% allogenic, 32.3% autologous, 19.3% second HSCT). The median time from HSCT to BSI was 62 days (interquartile range, 9 to 182 days). Gram-positive cocci accounted for 56.7% of the episodes; gram-negative bacilli, for 42%. The most common microorganisms were coagulase-negative staphylococci (30.6%) and Pseudomonas aeruginosa (15.9%). MDR gram-negative bacilli caused 11.9% of all episodes. Clinical characteristics, source of BSI, etiology, and outcomes changed depending on time since HSCT. Globally, 26.6% of episodes were treated with inappropriate empiric antibiotic therapy, more frequently in BSI episodes caused by P. aeruginosa, MDR P. aeruginosa, and MDR gram-negative bacilli. The 30-day mortality was 19.2%. Independent risk factors for mortality were BSI occurring ≥30 days after HSCT (odds ratio [OR], 11.21; 95% confidence interval [CI], 4.63 to 27.19), shock (OR, 7.10; 95% CI, 2.98 to 16.94), BSI caused by MDR P. aeruginosa (OR, 4.45; 95% CI, 1.12 to 17.72), and inappropriate empiric antibiotic therapy for gram-negative bacilli or Candida spp. (OR, 3.73; 95% CI, 1.27 to 10.89). HSCT recipients experiencing BSI have high mortality related to host and procedure factors, causative microorganism, and empiric antibiotic therapy. Strategies to identify HSCT recipients at risk of MDR P. aeruginosa and reducing inappropriate empiric antibiotic therapy are paramount to reduce mortality.

Characterization of a Multi-Metal Resistant Bacillus cereus Strain TWSL_5 and it’s Bioremediation Potential for Cr, Pb, Zn and Fe

Characterization of a Multi-Metal Resistant Bacillus cereus Strain TWSL_5 and it’s Bioremediation Potential for Cr, Pb, Zn and Fe

Phenotypic and Genotypic Characterization of Metallo Beta Lactamases among Gram-Negative Uropathogens from a Tertiary Care Hospital in Egypt: A Cross Sectional Study

Background: Gram Negative bacilli (GNB) are the most common causes of urinary tract infections (UTIs). There is a worrying level of antimicrobial resistance emerging in UTIs pathogens. Metallo-β-lactamases (MBLs) are rapidly spreading β-lactamases with no available FDA approved inhibitor conferring resistance to most β-lactam antibiotics including carbapenems. We aimed to determine prevalence and antimicrobial resistance patterns of Gram-negative uropathogens in our tertiary care hospital, and to characterize MBLs production among them.Methods: A hundred and forty-three urine samples were collected from the Urology Department. Uropathogens were isolated on Cystiene Lactose Electrolyte Deficient agar and Mac-Conkey’s agar. GNB were identified by conventional methods. Antimicrobial susceptibility was evaluated by disc diffusion method. Carbapenems resistant Gram-negative bacilli (CRGNB) were tested for MBLs production both phenotypically and genotypically.Results: Eighty-five GNB (75.9%) were isolated from 112 positive cultures. Escherichia coli (49.4%) was the most prevalent isolate. Most of GNB showed high resistance patterns to various antimicrobials. Twenty-nine GNB isolates were resistant to at least one carbapenem (28.2% for imipenem, 30.6% for meropenem). Twenty-three isolates (79.3%) were phenotypically positive for MBL activity by combined disc test (CDT). Twenty-two isolates (75.9%) were positive for one or more of MBL genes (blaIMP, blaVIM and/or blaNDM).Conclusions: Our study emphasized on the alarming rates of resistance to most of the common antimicrobials particularly carbapenems among GNB uropathogens, which represent a public health threat. CRGNB isolates in our hospital are phenotypically and genotypically associated with MBLs production so an effective strategy to combat these strains is mandatory.