NDM-producing Enterobacterales prevalence associated to COVID-19 in a tertiary hospital.

Colonizations/Infections caused by carbapenem-resistant Enterobacterales are of great clinical and epidemiological importance due to their rapid dissemination and high mortality rates. In this scenario, the use of antibiotics intensified by the COVID-19 pandemic has brought about a great warning on the real impact that this pandemic could have on antimicrobial management programs and long-term antimicrobial resistance rates. The objective of this study was to evaluate the increase of New Delhi Metallo ß-Lactamase (NDM)-producing Enterobacterales cases in COVID-19 units of a complex Brazilian tertiary hospital. This retrospective observational study included all patients admitted to the hospital identified as colonized or infected by NDM-producing Gram negative bacilli (GNB), from January 2017 to April 2021. Forty-two NDM-producing Enterobacterales were identified in 39 patients. The rate of NDM cases per total surveillance cultures increased progressively between 2017 and 2021 (chi-2 for trend, p < 0.0001) and was associated with a higher occurrence specifically in COVID units (Fisher exact, p < 0.0001). The molecular investigation of the NDM-producing Klebsiella pneumoniae strains revealed the emergence of diverse clones during the COVID-19 period, also with possible evidence of horizontal transmission among patients within COVID units. NDM-producing Enterobacterales with multiple and different clonalities in the COVID-19 units also raised questions about the importance of other factors besides horizontal clonal transfer, including the increase of antimicrobial consumption by these patients.

NDM-producing Enterobacterales prevalence associated to COVID-19 in a tertiary hospital

Abstract Colonizations/Infections caused by carbapenem-resistant Enterobacterales are of great clinical and epidemiological importance due to their rapid dissemination and high mortality rates. In this scenario, the use of antibiotics intensified by the COVID-19 pandemic has brought about a great warning on the real impact that this pandemic could have on antimicrobial management programs and long-term antimicrobial resistance rates. The objective of this study was to evaluate the increase of New Delhi Metallo β-Lactamase (NDM)-producing Enterobacterales cases in COVID-19 units of a complex Brazilian tertiary hospital. This retrospective observational study included all patients admitted to the hospital identified as colonized or infected by NDM-producing Gram negative bacilli (GNB), from January 2017 to April 2021. Forty-two NDM-producing Enterobacterales were identified in 39 patients. The rate of NDM cases per total surveillance cultures increased progressively between 2017 and 2021 (chi-2 for trend, p < 0.0001) and was associated with a higher occurrence specifically in COVID units (Fisher exact, p < 0.0001). The molecular investigation of the NDM-producing Klebsiella pneumoniae strains revealed the emergence of diverse clones during the COVID-19 period, also with possible evidence of horizontal transmission among patients within COVID units. NDM-producing Enterobacterales with multiple and different clonalities in the COVID-19 units also raised questions about the importance of other factors besides horizontal clonal transfer, including the increase of antimicrobial consumption by these patients.

NDM-producing enterobacterales prevalence associated to COVID-19 in a tertiary hospital

Colonizations/Infections caused by carbapenem-resistant Enterobacterales are of great clinical and epidemiological importance due to their rapid dissemination and high mortality rates. In this scenario, the use of antibiotics intensified by the COVID-19 pandemic has brought about a great warning on the real impact that this pandemic could have on antimicrobial management programs and long-term antimicrobial resistance rates. The objective of this study was to evaluate the increase of New Delhi Metallo b-Lactamase (NDM)-producing Enterobacterales cases in COVID-19 units of a complex Brazilian tertiary hospital. This retrospective observational study included all patients admitted to the hospital identified as colonized or infected by NDM-producing Gram negative bacilli (GNB), from January 2017 to April 2021. Forty-two NDM-producing Enterobacterales were identified in 39 patients. The rate of NDM cases per total surveillance cultures increased progressively between 2017 and 2021 (chi-2 for trend, p < 0.0001) and was associated with a higher occurrence specifically in COVID units (Fisher exact, p < 0.0001). The molecular investigation of the NDM-producing Klebsiella pneumoniae strains revealed the emergence of diverse clones during the COVID-19 period, also with possible evidence of horizontal transmission among patients within COVID units. NDM-producing Enterobacterales with multiple and different clonalities in the COVID-19 units also raised questions about the importance of other factors besides horizontal clonal transfer, including the increase of antimicrobial consumption by these patients.

Pharmacodynamic and immunomodulatory effects of polymyxin B in combination with fosfomycin against KPC-2-producing klebsiella pneumoniae

Abstract Determining the role of the immune response in preventing antimicrobial resistance and optimizing antibiotic regimens against carbapenemase-producing Klebsiella pneumoniae (KPC) is a research gap that exists and needs to be further explored. The objective of this study was to determine the pharmacodynamics and immunomodulatory effects of fosfomycin alone and in combination with polymyxin B against KPC-2-producing K. pneumoniae clinical isolates. Six K. pneumoniae isolates were selected (polymyxin B_MIC: 0.5-64 mg/L; Fosfomycin MIC: 16-128 mg/L) to evaluate the pharmacodynamics of mono- and combination therapies in static time-kill studies. A mechanism based model was used to characterize the joint activity of polymyxin B and fosfomycin. A549 human airway epithelial cells were infected with four isolates to evaluate the immunomodulatory effects of treatment. Our mechanism-based model indicated greater bacterial killing efficacy of fosfomycin with polymyxin B compared to monotherapy. In combination, polymyxin B was assumed to exert an outer membrane effect which resulted in an increase in fosfomycin's ability to reach its target site. The mechanism based model described the data well across all six strains with R2 values ranging from 0.705 to 0.935. The combination reduced K. pneumoniae-induced IL-6 and IL-8 but not TNF-α expression. The reduction in cytokine expression was greater with polymyxin B than fosfomycin alone, and combinations showed significantly greater reductions compared to monotherapies. Our findings suggest that further research is needed to understand immune-mediated killing to identify a strategy which harnesses the power of the immune response against these hard to treat bacteria in an in vivo system.

Pharmacodynamic and immunomodulatory effects of polymyxin B in combination with fosfomycin against KPC-2-producing Klebsiella pneumoniae.

Determining the role of the immune response in preventing antimicrobial resistance and optimising antibiotic regimens against carbapenemase-producing Klebsiella pneumoniae is a research gap that exists and needs to be further explored. The objective of this study was to determine the pharmacodynamic and immunomodulatory effects of fosfomycin alone and in combination with polymyxin B against KPC-2-producing K. pneumoniae clinical isolates. Six K. pneumoniae isolates were selected (polymyxin B MIC, 0.5-64 mg/L; fosfomycin MIC, 16-128 mg/L) to evaluate the pharmacodynamics of monotherapy and combination therapies in static time-kill studies. A mechanism-based model was used to characterise the joint activity of polymyxin B and fosfomycin. A549 human airway epithelial cells were infected with four isolates to evaluate the immunomodulatory effects of treatment. Our mechanism-based model indicated greater bacterial killing efficacy of fosfomycin with polymyxin B compared with monotherapy. In combination, polymyxin B was assumed to exert an outer membrane effect that resulted in an increase in the ability of fosfomycin to reach its target site. The mechanism-based model described the data well across all six strains, with R2 values ranging from 0.705-0.935. Combination therapy reduced K. pneumoniae-induced IL-6 and IL-8 but not TNFα expression. The reduction in cytokine expression was greater with polymyxin B than fosfomycin alone; combination therapy showed significantly greater reduction compared to either monotherapy. Our findings suggest that further research is needed to better understand immune-mediated killing in order to identify a strategy which harnesses the power of the immune response against these hard-to-treat bacteria.

Serological Testing for COVID-19, Immunological Surveillance, and Exploration of Protective Antibodies.

Serological testing is a powerful tool in epidemiological studies for understanding viral circulation and assessing the effectiveness of virus control measures, as is the case of SARS-CoV-2, the pathogenic agent of COVID-19. Immunoassays can quantitatively reveal the concentration of antiviral antibodies. The assessment of antiviral antibody titers may provide information on virus exposure, and changes in IgG levels are also indicative of a reduction in viral circulation. In this work, we describe a serological study for the evaluation of antiviral IgG and IgM antibodies and their correlation with antiviral activity. The serological assay for IgG detection used two SARS-CoV-2 proteins as antigens, the nucleocapsid N protein and the 3CL protease. Cross-reactivity tests in animals have shown high selectivity for detection of antiviral antibodies, using both the N and 3CL antigens. Using samples of human serum from individuals previously diagnosed by PCR for COVID-19, we observed high sensitivity of the ELISA assay. Serological results with human samples also suggest that the combination of higher titers of antiviral IgG antibodies to different antigen targets may be associated with greater neutralization activity, which can be enhanced in the presence of antiviral IgM antibodies.

Evaluation Strategies for Triple-Drug Combinations against Carbapenemase-Producing Klebsiella Pneumoniae in an In Vitro Hollow-Fiber Infection Model

Mounting antimicrobial resistance to carbapenemase-producing Klebsiella pneumoniae (CPKP) highlights the need to optimize currently available treatment options. The objective of this study was to explore alternative dosing strategies that limit the emergence of resistance to preserve the utility of last-line antibiotics by: (i) evaluating the pharmacodynamic (PD) killing activity of simulated humanized exposures to monotherapy and two-drug and three-drug combinations against CPKP bacterial isolates with different resistance mechanisms; and (ii) optimizing polymyxin B (PMB) exposure simulated in the three-drug combination regimens to maximize the killing activity. Two CPKP clinical isolates (BAA2146 (NDM-1) and BRKP76 (KPC-2)) were evaluated over 168 hours using a hollow-fiber infection model simulating clinically relevant PMB, fosfomycin, and meropenem dosing regimens. PMB-based three-drug combinations were further optimized by varying the initial exposure (0­24 hours) or maintenance dose received over the duration of treatment. The area under the bacterial load-versus-time curve (AUCFU) was used to determine PD activity. Overall reductions in PMB exposure ranged from 2 to 84%. BAA2146 and BRKP76 had median (range) AUCFUs of 11.0 (10.6­11.6) log10 CFU hour/mL and 7.08 (7.04­11.9) log10 CFU hour/mL, respectively. The PMB "front loaded" 2.5 mg/ kg/day + 0.5 mg/kg maintenance dose in combination with meropenem and fosfomycin was a promising regimen against BRKP76, with an overall reduction in PMB exposure of 56% while still eradicating the bacteria. Tailored triple combination therapy allows for the optimization of dose and treatment duration of last-line agents like PMB to achieve adequate drug exposure and appropriate PD activity while minimizing the emergence of resistance.

Evaluation Strategies for Triple-Drug Combinations against Carbapenemase-Producing Klebsiella Pneumoniae in an In Vitro Hollow-Fiber Infection Model.

Mounting antimicrobial resistance to carbapenemase-producing Klebsiella pneumoniae (CPKP) highlights the need to optimize currently available treatment options. The objective of this study was to explore alternative dosing strategies that limit the emergence of resistance to preserve the utility of last-line antibiotics by: (i) evaluating the pharmacodynamic (PD) killing activity of simulated humanized exposures to monotherapy and two-drug and three-drug combinations against CPKP bacterial isolates with different resistance mechanisms; and (ii) optimizing polymyxin B (PMB) exposure simulated in the three-drug combination regimens to maximize the killing activity. Two CPKP clinical isolates (BAA2146 (NDM-1) and BRKP76 (KPC-2)) were evaluated over 168 hours using a hollow-fiber infection model simulating clinically relevant PMB, fosfomycin, and meropenem dosing regimens. PMB-based three-drug combinations were further optimized by varying the initial exposure (0-24 hours) or maintenance dose received over the duration of treatment. The area under the bacterial load-versus-time curve (AUCFU) was used to determine PD activity. Overall reductions in PMB exposure ranged from 2 to 84%. BAA2146 and BRKP76 had median (range) AUCFUs of 11.0 (10.6-11.6) log10  CFU hour/mL and 7.08 (7.04-11.9) log10 CFU hour/mL, respectively. The PMB "front loaded" 2.5 mg/kg/day + 0.5 mg/kg maintenance dose in combination with meropenem and fosfomycin was a promising regimen against BRKP76, with an overall reduction in PMB exposure of 56% while still eradicating the bacteria. Tailored triple-combination therapy allows for the optimization of dose and treatment duration of last-line agents like PMB to achieve adequate drug exposure and appropriate PD activity while minimizing the emergence of resistance.

Is it cost effective to use a 2% chlorhexidine wipes bath to reduce central-line associated blood stream infection? A quasi-experimental study.

BACKGROUND: Bathing with 2% chlorhexidine (CHG) wipes is an important measure regarding infection prevention in critically ill patients. The aim of this study was to evaluate the impact of CHG wipes bath to prevent central-line associated bloodstream infection (CLABSI) in critically ill patients and determine if such measure is cost-saving. METHODS: a quasi-experimental study, conducted from July 2017 to April 2019. Daily bath with 2% CHG was used in all patients at the unit in the intervention period. The following were evaluated: CLABSI incidence density in both periods, 30- day mortality, guided antimicrobials used to treat CLABSI and 2% CHG costs. RESULTS: CLABSI incidence density dropped from 8.69 to 1.83 per 1.000 central line-days (p = 0.001), mainly by Klebsiella pneumoniae Carbapenen Resistant (Kp-KPC) (p = 0.05). Costs with guided antimicrobials for the treatment in pre-intervention were US$ 46,114.36, and in the intervention period, US$ 4,177.50. The 2% CHG monthly cost was US$ 2,698.00, achieving 30% savings when comparing both periods. DISCUSSION: An expressive reduction of 79% in CLABSI incidence density was observed, mainly due to Kp-KPC infection and also a reduction in guided antimicrobial costs. CONCLUSIONS: Bathing with 2% CHG led to evident CLABSI reduction.

Coronary artery bypass surgery in patients with COVID-19: What have we learned ?

COVID-19 caused by the novel coronavirus SARS-CoV-2 led to the pandemic, causing unprecedented health and social crisis worldwide. Acute coronary syndromes patients, especially when coronary artery bypass graft (CABG) surgery is needed, may present with higher severity risk if affected by COVID-19. Extracorporeal circulation leads to activation of endothelium and microcirculatory network, which activates the coagulation, platelet aggregation and inflammation 1. COVID-19 may also course with severe inflammation, massive secretion of inflammatory cytokines, plaque rupture and a procoagulant state 2. Therefore, it is advisable to postpone surgeries interventions when possible. However, our institution is a public tertiary referral hospital for high-risk cardiovascular patients even in SARS-CoV-2 pandemic. We describe a series of thirteen high risk coronary artery disease patients submitted to CABG and who had COVID-19 infection during the same hospitalization, six patients had COVID-19 before surgery, three patients were operated with active infection and four patients were infected after surgery…

Is it cost effective to use a 2% chlorhexidine wipes bath to reduce central-line associated blood stream infection? A quasi-experimental study

BACKGROUND: Bathing with 2% chlorhexidine (CHG) wipes is an important measure regarding infection prevention in critically ill patients. The aim of this study was to evaluate the impact of CHG wipes bath to prevent central-line associated bloodstream infection (CLABSI) in critically ill patients and determine if such measure is cost-saving. METHODS: a quasi-experimental study, conducted from July 2017 to April 2019. Daily bath with 2% CHG was used in all patients at the unit in the intervention period. The following were evaluated: CLABSI incidence density in both periods, 30- day mortality, guided antimicrobials used to treat CLABSI and 2% CHG costs. RESULTS: CLABSI incidence density dropped from 8.69 to 1.83 per 1.000 central line-days (p = 0.001), mainly by Klebsiella pneumoniae Carbapenen Resistant (Kp-KPC) (p = 0.05). Costs with guided antimicrobials for the treatment in pre-intervention were US$ 46,114.36, and in the intervention period, US$ 4,177.50. The 2% CHG monthly cost was US$ 2,698.00, achieving 30% savings when comparing both periods. DISCUSSION: An expressive reduction of 79% in CLABSI incidence density was observed, mainly due to Kp-KPC infection and also a reduction in guided antimicrobial costs. CONCLUSIONS: Bathing with 2% CHG led to evident CLABSI reduction.

Serological Testing for COVID-19, Immunological Surveillance, and Exploration of Protective Antibodies

Serological testing is a powerful tool in epidemiological studies for understanding viral circulation and assessing the effectiveness of virus control measures, as is the case of SARS-CoV-2, the pathogenic agent of COVID-19. Immunoassays can quantitatively reveal the concentration of antiviral antibodies. The assessment of antiviral antibody titers may provide information on virus exposure, and changes in IgG levels are also indicative of a reduction in viral circulation. In this work, we describe a serological study for the evaluation of antiviral IgG and IgM antibodies and their correlation with antiviral activity. The serological assay for IgG detection used two SARS-CoV-2 proteins as antigens, the nucleocapsid N protein and the 3CL protease. Cross-reactivity tests in animals have shown high selectivity for detection of antiviral antibodies, using both the N and 3CL antigens. Using samples of human serum from individuals previously diagnosed by PCR for COVID-19, we observed high sensitivity of the ELISA assay. Serological results with human samples also suggest that the combination of higher titers of antiviral IgG antibodies to different antigen targets may be associated with greater neutralization activity, which can be enhanced in the presence of antiviral IgM antibodies.

Late ascending aortic prosthesis infection by porphyromonas pogonae: An unexpected infectious complication

Late complications in ascending aortic surgeries are uncommon and may occur by infectious processes, usually caused by gram positive bacteria. We report a case of aortic prosthesis infection by Porphyromonas pogonae, an anaerobic gram-negative coccobacillus that can grow under microaerobic conditions, three years after ascending aortic reconstruction surgery. (AU)

Late ascending aortic prosthesis infection by Porphyromonas pogonae: An unexpected infectious complication.

Late complications in ascending aortic surgeries are uncommon and may occur by infectious processes, usually caused by gram positive bacteria. We report a case of aortic prosthesis infection by Porphyromonas pogonae, an anaerobic gram-negative coccobacillus that can grow under microaerobic conditions, three years after ascending aortic reconstruction surgery.

Multifactorial chromosomal variants regulate polymyxin resistance in extensively drug-resistant Klebsiella pneumoniae.

Extensively drug-resistant Klebsiella pneumoniae (XDR-KP) infections cause high mortality and are disseminating globally. Identifying the genetic basis underpinning resistance allows for rapid diagnosis and treatment. XDR isolates sourced from Greece and Brazil, including 19 polymyxin-resistant and five polymyxin-susceptible strains, were subjected to whole genome sequencing. Seventeen of the 19 polymyxin-resistant isolates harboured variations upstream or within mgrB. The most common mutation identified was an insertion at nucleotide position 75 in mgrB via an ISKpn26-like element in the ST258 lineage and ISKpn13 in one ST11 isolate. Three strains acquired an IS1 element upstream of mgrB and another strain had an ISKpn25 insertion at 133 bp. Other isolates had truncations (C28STOP, Q30STOP) or a missense mutation (D29E) affecting mgrB. Complementation assays revealed all mgrB perturbations contributed to resistance. Missense mutations in phoQ (T281M, G385C) were also found to facilitate resistance. Several variants in phoPQ co-segregating with the ISKpn26-like insertion were identified as potential partial suppressor mutations. Three ST258 samples were found to contain subpopulations with different resistance-conferring mutations, including the ISKpn26-like insertion colonizing with a novel mutation in pmrB (P158R), both confirmed via complementation assays. These findings highlight the broad spectrum of chromosomal modifications which can facilitate and regulate resistance against polymyxins in K. pneumoniae.

Evaluation of Activity and Emergence of Resistance of Polymyxin B and ZTI-01 (Fosfomycin for Injection) against KPC-Producing Klebsiella pneumoniae.

ZTI-01 (fosfomycin for injection) is a broad-spectrum antibiotic with a novel mechanism of action and is currently under development in the United States for treatment of complicated urinary tract infections. Globally, fosfomycin and polymyxin B are increasingly being used to treat multidrug-resistant Gram-negative infections. The objectives were to evaluate the pharmacodynamic activity of polymyxin B and fosfomycin alone and in combination against KPC-producing Klebsiella pneumoniae and to assess the rate and extent of emergence of resistance to different antibiotic regimens. Two clinical isolates, BRKP26 (MIC of polymyxin B[MICPMB], 0.5 mg/liter; MIC of fosfomycin [MICFOF], 32 mg/liter) and BRKP67 (MICPMB, 8 mg/liter; MICFOF, 32 mg/liter) at an initial inoculum of 107 CFU/ml, were evaluated over 168 h in a hollow-fiber infection model simulating clinically relevant polymyxin B (2.5-mg/kg loading dose as a 2 h-infusion followed by 1.5-mg/kg dose every 12 h [q12h] as a 1-h infusion) and fosfomycin (6 g q6h as a 1-h or 3-h infusion) regimens alone and in combination. Population analysis profiles (PAPs) and MIC testing were performed to assess emergence of resistance. Polymyxin B or fosfomycin monotherapy was ineffective and selected for resistance by 24 h. Polymyxin B plus a fosfomycin 1-h infusion demonstrated sustained bactericidal activity by 4 h, with undetectable colony counts beyond 144 h. Polymyxin B plus a fosfomycin 3-h infusion demonstrated bactericidal activity at 4 h, followed by regrowth similar to that of the control by 144 h. PAPs revealed resistant subpopulations by 120 h. The combination of polymyxin B and a fosfomycin 1-h infusion is a promising treatment option for KPC-producing K. pneumoniae and suppresses the emergence of resistance. Further evaluation of novel dosing strategies is warranted to optimize therapy.

Multifactorial chromosomal variants regulate polymyxin resistance in extensively drug-resistant Klebsiella pneumoniae

Extensively drug-resistant Klebsiella pneumoniae (XDR-KP) infections cause high mortality and are disseminating globally. Identifying the genetic basis underpinning resistance allows for rapid diagnosis and treatment. XDR isolates sourced fromGreece and Brazil, including 19 polymyxin-resistant and five polymyxin-susceptible strains, were subjected to whole genomesequencing. Seventeen of the 19 polymyxin-resistant isolates harboured variations upstream or within mgrB. The mostcommon mutation identified was an insertion at nucleotide position 75 in mgrB via an ISKpn26-like element in the ST258lineage and ISKpn13 in one ST11 isolate. Three strains acquired an IS1 element upstream of mgrB and another strain had anISKpn25 insertion at 133 bp...

Successful use of gentamycin as an antibiotic prophylaxis regimen to reduce the rate of healthcare-associated infections after renal transplantation.

At our institution, we observed an increase in the incidence of healthcare-associated infections (HAI) due to Gram-negative bacilli, including three cases of carbapenem-resistant Klebsiella pneumoniae, among patients who underwent renal transplantation. In addition to strengthening infection control measures, we chose to add gentamycin to the antibiotic prophylaxis regimen of patients undergoing renal transplantation. We assessed the number of HAI occurring within 30 days of renal transplantation during two time periods: (1) the pre-intervention period, between September 2009 and June 2010, and (2) the post-intervention period, between July 2010 and April 2011. The intervention consisted of the addition of gentamycin to the surgical antibiotic prophylaxis regimen. The percentage of patients with HAIs was 31% lower during the post-intervention period (p=0.03), with the greatest reductions observed for urinary tract infections (p=0.024). Carbapenem-resistant K. pneumoniae was not isolated during this period. The investigated patients did not exhibit worsening renal function. Further studies are needed to assess antibiotic prophylaxis in renal transplantation patients at institutions where there is a high prevalence of multidrug-resistant Gram-negative bacteria.

Successful use of gentamycin as an antibiotic prophylaxisregimen to reduce the rate of healthcare-associatedinfections after renal transplantation / Successful use of gentamycin as an antibiotic prophylaxis regimen to reduce the rate of healthcare-associated infections after renal transplantation

At our institution, we observed an increase in the incidence of healthcare-associated infections(HAI) due to Gram-negative bacilli, including three cases of carbapenem-resistantKlebsiella pneumoniae, among patients who underwent renal transplantation. In additionto strengthening infection control measures, we chose to add gentamycin to the antibioticprophylaxis regimen of patients undergoing renal transplantation. We assessed the numberof HAI occurring within 30 days of renal transplantation during two time periods: (1) the preinterventionperiod, between September 2009 and June 2010, and (2) the post-interventionperiod, between July 2010 and April 2011. The intervention consisted of the addition of gentamycinto the surgical antibiotic prophylaxis regimen. The percentage of patients withHAIs was 31% lower during the post-intervention period (p = 0.03), with the greatest reductionsobserved for urinary tract infections (p = 0.024). Carbapenem-resistant K. pneumoniaewas not isolated during this period. The investigated patients did not exhibit worseningrenal function. Further studies are needed to assess antibiotic prophylaxis in renal transplantationpatients at institutions where there is a high prevalence of multidrug-resistantGram-negative bacteria.