Prevalence and risk factors of Gram-negative bacilli causing blood stream infection in patients with malignancy

Bloodstream gram-negative bacterial infections in adult patients with leukemia: A retrospective review of medical records in a tertiary care hospital in Western Saudi Arabia

BACKGROUND

Patients with neutropenic cancers are at high risk of acquiring infections, especially if on chemotherapy. Gram-negative bacterial infections are associated with high mortality. This study aimed to assess clinical characteristics, outcomes, and epidemiology of gram-negative bacterial (GNB) bloodstream infections (BSI) in adult patients with leukemia.

METHODS

This single-center, retrospective study included 102 adult patients diagnosed with leukemia between 2017 and 2019. The patients' demographics, infection diagnosis, leukemia diagnosis, comorbidities, and infection outcomes were collected from electronic medical records.

RESULTS

The most common GNB were Klebsiella pneumoniae (33.3 %), Pseudomonas aeruginosa (23.5 %), and Escherichia coli (17.6 %). Additionally, 36.7 % of infections were multidrug resistant. The most common comorbidities were cardiovascular diseases (36.7 %), diabetes mellitus (33.3 %), and liver diseases (24.1 %). GNB-infected patients had a higher mortality than noninfected patients (35.3 % and 11.8 %, respectively, p = 0.005). In a multivariable analysis, patients with acute myeloid leukemia and acute lymphoid leukemia were significantly more likely to acquire GNB BSI (p = 0.01), while patients with chronic myelogenous leukemia and chronic lymphocytic leukemia had a lower likelihood of developing GNB BSI. In addition, low hemoglobin level was an independent risk factor of GNB BSI (p = 0.001). Chemotherapeutic agents showed an association with increased risk of GNB BSI.

CONCLUSIONS

Patients with acute leukemia and low hemoglobin levels have increased risk of GNB BSI, which was associated with increased mortality. Prospective studies are needed to further assess the effect of co-morbidities and chemotherapy medications on the occurrence of GNB BSI according to the type of leukemia.

High Prevalence of GES-5 Variant and Co-Expression of VIM-2 and GES-45 among Clinical Pseudomonas aeruginosa Strains in Tunisia

Carbapenem-resistant Pseudomonas aeruginosa (CRPA) are a global health concern. The antimicrobial resistance, virulence, and molecular typing of 57 CRPA isolated from 43 patients who attended a specific Tunisian hospital from September 2018 to July 2019 were analyzed. All but one were multidrug-resistant CRPA, and 77% were difficult-to-treat-resistant (DTR) isolates. The blaVIM-2 gene was detected in four strains (6.9%), and among the 36 blaGES-positive CRPA (62%), the blaGES-5 gene was the predominant variant (86%). Three strains co-harbored the blaVIM-2 and blaGES-45 genes, and seven CRPA carried the blaSHV-2a gene (14%). OprD alterations, including truncations by insertion sequences, were observed in 18 strains. Regarding the 46 class 1 integron-positive CRPA (81%), the blaGES-5 gene was located in integron In717, while the blaGES-29 and blaGES-45 genes were found in two new integrons (In2122 and In4879), and the blaVIM-2 gene was found in In1183 and the new integron In2142. Twenty-four PFGE patterns and thirteen sequence types (three new ones) were identified. The predominant serotype O:11 and exoU (81%) were mostly associated with ST235 and the new ST3385 clones. The seven blaSHV-2a-CRPA from different patients belonged to ST3385 and the same PFGE pattern. The blaGES-5- and blaVIM-2 + blaGES-45-positive CRPA recovered mostly from ICU patients belonged to the high-risk clone ST235. Our results highlight the alarming prevalence of blaGES-5- and ST235-CRPA, the co-existence of blaGES-45 and blaVIM-2, and their location within integrons favoring their dissemination.

Clinical characteristics of bloodstream infections in adult patients with solid tumours and a nomogram for mortality prediction: a 5-year case-controlled retrospective study in a tertiary-level hospital

Background

Bloodstream infections (BSIs) are one of the leading causes of death in cancer patients. Nevertheless, the risk factors of BSIs in solid tumors have rarely been ascertained adequately.

Methods

We conducted a single-center case-controlled retrospective study from 2017 to 2021 among adults with solid tumors in a tertiary-level hospital. The BSIs and control group were matched by the propensity score matching method. We found independent risk factors of occurrence and death of BSIs using univariate and multivariate regression analysis. Additionally, a nomogram was constructed to predict the risk of mortality in BSIs.

Results

Of 602 patients with solid tumors in the study period, 186 had BSIs and 416 had non-BSIs. The incidence of BSIs was 2.0/1,000 admissions (206/102,704), and the 30-day mortality rate was 18.8% (35/186). Compared to the control group, the BSIs had longer hospital stays (24.5 days vs. 20.0 days), and higher frequency complicating with organ failure (10.5% vs. 2.4%), nephropathy (19.6% vs. 3.8%), comorbidities≥3 (35.5% vs. 20.0%), and liver-biliary-pancreatic infections (15.6% vs. 5.3%) (all P<0.001). Among the 186 patients with BSIs, 35 died within 30 days after BSIs. Gram-negative bacteria were the most frequent microorganisms (124/192, 64.6%). Liver cancer, organ failure, a high level of lactate dehydrogenase and septic shock were the independent hazardous factors for death of BSIs. What's more, a nomogram was constructed to predict the 30-day survival rate of BSIs, which was proved to have good accuracy (AUC: 0.854; 95% confidence interval: 0.785~0923) and consistency.

Conclusion

Being aware of the risk factors of BSIs redounds to take preventive measures to reduce the incidence and death of BSIs.

The Prevalence of Multidrug-Resistant Acinetobacter baumannii and Its Vaccination Status among Healthcare Providers

There is growing concern among healthcare providers worldwide regarding the prevalence of multidrug-resistant Acinetobacter baumannii (A. baumannii). Some of the worst hospital-acquired infections, often in intensive care units (ICUs), are caused by this bacterial pathogen. In recent years, the rise in multidrug-resistant A. baumannii has been linked to the overuse of antimicrobial drugs and the lack of adequate infection control measures. Infections caused by this bacterial pathogen are the result of prolonged hospitalization and ICU stays, and they are associated with increased morbidity and mortality. This review outlines the epidemiology, risk factors, and antimicrobial resistance associated with A. baumannii in various countries, with a special focus on the Kingdom of Saudi Arabia. In response to the growing concern regarding this drug-resistant bacteria, fundamental information about its pathology has been incorporated into the development of vaccines. Although these vaccines have been successful in animal models, their effectiveness in humans remains unproven. The review will discuss the development of A. baumannii vaccines, potential related obstacles, and efforts to find an effective strategy against this pathogen.

Clinical application value of metagenomic second-generation sequencing technology in hematologic diseases with and without transplantation

Introduction

Hematological patients are at risk of infections. It is unknown whether the pathogenic microbial spectrum differs between HSCT and non-HSCT patients, and whether metagenomic next-generation sequencing (mNGS) of peripheral blood can be used as a substitute test specimen such as alveolar lavage.

Methods

A retrospective study was conducted to evaluate the clinical application value of mNGS in hematological patients with and without HSCT.

Results

Viruses were prevalent pathogens in both non-HSCT (44%) and HSCT (45%) patients, chiefly human cytomegalovirus and Epstein-Barr virus. In non-HSCT patients, Gram-negative bacilli accounted for 33% (predominantly Klebsiella pneumonia), and Gram-positive cocci accounted for 7% (predominantly Enterococcus faecium) of pathogens. However, in HSCT patients, Gram-negative bacilli accounted for 13% (predominantly Stenotrophomonas maltophilia), and Gram-positive cocci accounted for 24% (predominantly Streptococcus pneumonia) of pathogens. Mucor was the most common fungu s in two groups. The positive rate of pathogens by mNGS was 85.82%, higher than conventional detection (20.47%, P < 0.05). Mixed infection accounted for 67.00%, among which the mixed infection of bacteria and virus (25.99%) was the most common. 78 cases had pulmonary infection, the positive rate of traditional laboratory tests was 42.31% (33/78), and of mNGS in peripheral blood was 73.08% (57/78), showing a statistical difference (P = 0.000). The non-HSCT patients had a higher frequency of Klebsiella pneumonia (OR=0.777, 95% CI, 0.697-0.866, P = 0.01) and Torque teno virus (OR=0.883, 95% CI, 0.820-0.950, P = 0.031) infections than HSCT patients, while the rates of Streptococcus pneumonia (OR=12.828, 95% CI, 1.378-119.367, P = 0.016), Candida pseudosmooth (OR=1.100, 95% CI, 0.987-1.225, P = 0.016), human betaherpesvirus 6B (OR=6.345, 95% CI, 1.105-36.437, P = 0.039) and human polyomavirus 1 (OR=1.100, 95% CI, 0.987-1.225, P = 0.016) infections were lower. Leishmania could be detected by mNGS.

Conclusion

mNGS of peripheral blood can be used as a substitute test method for hematological patients with pulmonary infection, the detection rate of mixed infections by mNGS was high, and mNGS has high clinical recognition rate and sensitivity in pathogen detection, and provides a basis for guiding the anti-infective treatment in hematological diseases with symptoms such as fever.

Risk Factors for Infection With Multidrug-Resistant Gram-Negative Bacteria in a Tertiary Care Hospital in Saudi Arabia: A Case-Control Study

Background The increase in the incidence of multidrug-resistant (MDR) organisms especially Gram-negative bacteria (GNB) in healthcare facilities is a serious cause of concern. This study identified risk factors for the infection with these MDR GNB, such as Acinetobacter baumannii, Klebsiella pneumoniae, Pseudomonas aeruginosa, and Escherichia coli to inform healthcare workers about strategies for their containment. Methods A case-control study was carried out at a tertiary care hospital where 100 patients with healthcare-associated infections (infections arising 48 hours after admission) caused by MDR GNB were compared with two control groups, i.e., 100 patients with healthcare-associated infections caused by non-MDR GNB (not meeting the criteria of MDR) and 100 patients without infection caused by GNB. MDR bacteria were defined as the ones that were non-susceptible to at least one antibiotic in three or more classes of antibiotics. The data were analyzed using descriptive statistics (frequency and percentage of categorical variables). Multivariate regression analysis was undertaken to identify significant predictors of MDR GNB. Odds ratios with 95% confidence intervals were calculated, and the level of significance was determined at p-value < 0.05. Results A total of 388 organisms were isolated during four months (January-April 2015) from 332 patients. Fifty-six (17%) of the patients were infected with more than one organism. Among the MDR bacteria, the most dominant MDR organism was A. baumannii (38%), followed by K. pneumoniae (31%), P. aeruginosa (20%), and E. coli (11%). Among the non-MDR organisms, the most dominant was P. aeruginosa (47%), followed by E. coli (32%), K. pneumoniae (18%), and A. baumannii (3%). Patients with MDR organisms compared with the first control group (patients with non-MDR organisms) showed that prior antibiotic use (p-value: 0.001), intensive care unit (ICU) admission (p-value: 0.001), and indwelling medical devices (p-value: 0.005) were significant risk factors for MDR infections. It was also found that the risk factors for MDR GNB infection were the same in the second control group (patients without infection): prior antibiotic use (p-value: 0.002), ICU admission (p-value: 0.001), and indwelling medical devices (p-value: 0.03). Based on the comparison of the two control groups, prolonged hospital stays of more than five days (p-value: 0.001), immunosuppressive therapy (p-value: 0.02), and over 60 years of age (p-value: 0.02) were significant risk factors for non-MDR infection. Conclusion  The risk factors identified in our study provide guidance to healthcare workers for the prevention and containment of MDR GNB.

Bacterial Infections among Patients with Chronic Diseases at a Tertiary Care Hospital in Saudi Arabia

Infections caused by multi-drug-resistant bacteria in patients with chronic diseases have been associated with high mortality and morbidity. While few reports have evaluated bacterial infections in multiple chronic disease patients, the focus of the current study was to investigate the prevalence of bacterial infections and the susceptibility profiles of causative strains among various groups of patients suffering from chronic diseases. Microbiological reports of patients suffering from cancer, diabetes mellitus, cardiovascular diseases, kidney diseases, and skin burns were retrospectively collected from a tertiary hospital in Saudi Arabia. Approximately 54.2% of recruited patients were males, and positive urine was the most prevalent specimen associated with kidney disease patients (25%). Escherichia coli isolates were predominant among cardiovascular, kidney, and cancer patients. Staphylococcus aureus was commonly detected in diabetics and those with burns. Although resistance patterns varied based on the type of specimens and underlying diseases, Escherichia coli showed limited resistance to colistin, carbapenems, and tigecycline, while S. aureus demonstrated susceptibility to ciprofloxacin, gentamicin, and rifampin. These observations are crucial for clinicians and policymakers to ensure effective treatment plans and improve outcomes in these patients with comorbidity.

A novel prognostic model for malignant patients with Gram-negative bacteremia based on real-world research

Gram-negative bacteremia (GNB) is a common complication in malignant patients. Identifying risk factors and developing a prognostic model for GNB might improve the survival rate. In this observational and real-world study, we retrospectively analyzed the risk factors and outcomes of GNB in malignant patients. Multivariable regression was used to identify risk factors for the incidence of GNB, while Cox regression analysis was performed to identify significant prognostic factors. A prognostic model was constructed based on Cox regression analysis and presented on a nomogram. ROC curves, calibration plots, and Kaplan–Meier analysis were used to estimate the model. It comprised 1004 malignant patients with Bloodstream infection (BSI) in the study cohort, 65.7% (N = 660) acquired GNB. Multivariate analysis showed gynecologic cancer, hepatobiliary cancer, and genitourinary cancer were independent risk factors related to the incidence of GNB. Cox regression analysis raised that shock, admission to ICU before infection, pulmonary infection, higher lymphocyte counts, and lower platelet counts were independent risk factors for overall survival (OS). The OS was significantly different between the two groups classified by optimal cut-off value (log-rank, p < 0.001). Above all, a nomogram was created based on the prognostic model, which was presented on a website freely. This real-world study was concentrated on the malignant patients with GNB and proved that shock, admission to ICU before infection, pulmonary infection, higher lymphocyte counts, and lower platelet counts were related to the death of these patients. And a prognostic model was constructed to estimate the risk score of mortality, further to reduce the risk of death.

Clinical factors predictive of Gram-negative bloodstream infection at the Emergency Department

Introduction

Bloodstream infection is a common condition at the Emergency Department (ED). Appropriate antibiotic therapy is also crucial for patients with bloodstream infection particularly at the ED. This study therefore aimed to find clinical factors predictive of types of bacterial pathogens in bloodstream infection patients presenting at the ED focused on Gram-negative bacterial infections.

Methods

This was a retrospective study. The inclusion criteria were adult patients who were suspected for bloodstream infection defined by blood culture collection presenting at the ED and intravenous antibiotics were initiated during the ED visits. The study period was between January 1^st, 2016 and December 31^st, 2018. Clinical data of the eligible patients were retrieved from the ED database. Factors associated with Gram-negative infection were calculated by logistic regression analysis.

Results

There were 727 patients at the ED who had positive blood culture for bacteria. Of those, 504 patients (69.33%) had positive blood culture for Gram-negative bacteria. There were three independent factors for Gram-negative infection including sex, solid organ malignancy, and body temperature. The highest adjusted odds ratio (95% confidence interval) was 2.004 (1.330, 3.020) for solid organ malignancy.

Conclusions

Gram-negative bacterial infection was more prominent than Gram-positive bacterial infection in patients presenting at the ED (69.33%). Solid organ malignancy, being female, and a high body temperature were independent factors of Gram-negative bacterial infection.

Factors Associated with Gram-Negative Bacteremia and Mortality in Neutropenic Patients with Hematologic Malignancies in a High-Resistance Setting

Objective

Patients with hematological malignancies (HMs) have a substantial incidence of febrile neutropenic episodes. Gram-negative bacteremia (GNB) is still the major cause of these episodes. We evaluated the factors associated with GNB and mortality of bacteremic patients with HMs in a high-resistance setting.

Materials and Methods

We conducted a prospective cohort study from March 2018 to June 2019 with 66 bacteremic and 132 non-bacteremic patients. Regression analyses were used to identify factors associated with GNB and 30-day mortality.

Results

The mean age was 53.83±15.21 years, and 129 (65.2%) of the patients were male. In multivariable analysis, factors independently associated with GNB were male gender, duration of hospitalization and neutropenia before the febrile neutropenic episode, leukemias and allogeneic transplant recipients, radiotherapy, receiving glucocorticosteroids, colonization with resistant microorganisms. All-cause mortality and 30-day mortality were 47.0% and 30.3% in cases of GNB, compared to non-bacteremic controls 25.0% and 10.6%, respectively. Sepsis, duration of hospitalization before the febrile neutropenic episode, carbapenem-resistant GNB, and inappropriate empirical antibiotic treatment was found as factors associated with 30-day mortality. Prior antibiotic exposure particularly beta-lactamase inhibitor combinations and carbapenems during the past 30 days was more frequent in the bacteremic group. An increasing trend was observed in multidrug-resistant (MDR) bacteria (p=0.03) and carbapenem-resistant Enterobacterales (p=0.02) over the years.

Conclusion

By considering the risk factors associated with GNB and 30-day mortality that we detected in our study among neutropenic patients, a personalized approach for the management of febrile neutropenic patients can be designed by means of an effective antimicrobial stewardship program including the appropriate use of broad-spectrum antibiotics.

Microbial spectrum and drug resistance profile in solid malignancies in a large tertiary hospital from Palestine

BACKGROUND

Since the available data for bloodstream infections in solid malignancy tumors are somewhat limited in Palestine, prevention of infection before the occurrence, controlling it when it occurs, and implementing stewardship programs are important ways in the whole therapy of solid tumor patients, which is becoming challenging recently with the evolution of more antimicrobial drug-resistant pathogens. Therefore, our study aims to assess the microbial spectrum and antimicrobial sensitivity and the overall outcome related to many clinical risk factors in patients with solid tumor patients seeking care in a referral hospital as an experience from a developing country.

METHODS

From the onset of 2018 to the end of 2020, a total of 116 episodes with positive blood cultures were retrospectively studied and analyzed in 96 patients who had solid tumors in a referral hospital in Palestine.

RESULTS

We identified 116 positive blood cultures in 96 patients with a male to female ratio of 1:1. The mean age was 58 years. Breast cancer was the tumor most frequently recorded (13.5%), followed by urinary tract tumors (10.4%). The most common source of episodes with positive blood culture was catheter-related. Gram-positive bacteria accounted for 52.6% of blood cultures with the predomination of Staphylococcus species. On the contrary, Gram-negative bacteria were documented in 39.7% of the cultures, with E. coli being the most frequent bacteria. Regarding fungi that were only Candida species, it was isolated in 15.5% of the cultures.28.4% of patients started on a single antimicrobial as an initial regimen, the remaining started combination antimicrobial therapy. The initial antimicrobials used most frequently were aminoglycosides in 29.3% of the episodes. All species of Staphylococcus were sensitive to vancomycin. Enterococcus species were fully resistant to ciprofloxacin. In the case of E. coli, the isolates were 100% sensitive to imipenem, meropenem, and amikacin and were mostly resistant to ampicillin, where the sensitivity was only about 19.5%. P.aeruginosa was sensitive in 83.3% of cultures to both piperacillin-tazobactam and gentamicin, but highly resistant to imipenem, in which sensitivity decreased to 50%. The isolates of Klebsiella species were 72.2% sensitive to gentamicin, meropenem, and imipenem and 100% resistant to ampicillin. A. baumannii was 50% sensitive to trimethoprim-sulfamethoxazole. Candida species showed high sensitivity to both caspofungin and flucytosine (83.3%), followed by 77.8% sensitivity to voriconazole. Death was reported in 27.6% of the episodes and there was a significant relationship between shock at presentation and death (p = 0.010).

CONCLUSIONS

The findings of this investigation confirm the prevalent BSI seen in patients with solid malignancies and demonstrate a significant percentage of antibiotic resistance. Therefore, stewardship programs that dig deep before using any type of antimicrobials will help reduce the risk of resistance to antibiotics. In addition, the implementation of infection control surveillance plays an important role in decreasing the risk of contamination.

Occurrence and Resistance Pattern of Gram-Negative Bacteremia and Sepsis in A Tertiary Care Hospital - A Four-Year Study

The rise in antibiotic resistance has been a major source of public health concern. As a result, mortality and morbidity rates have risen significantly. This study was done to identify gram-negative organisms causing bacteremia/sepsis, study their prevalence rates, and antimicrobial resistance patterns, as evidence-based knowledge of gram-negative organisms causing sepsis and their resistance profiles is essential for effective hospital control and better management of infections caused by resistant bacteria. A retrospective study, conducted from January 2016 to December 2019, blood samples were collected using aseptic guidelines and cultured using automated blood culture methods. Biochemical tests were done according to microbiology standard procedures, while antimicrobial testing was done according to CLSI guidelines. A total of 13,808 blood samples were received within the study period of four years. Of the total, 2079 showed significant growth, with 765 being GNB isolates. The most common isolates were Escherichia coli (35.42%), Klebsiella pneumonia (19.74%), Acinetobacter species (9.67%), and other non-fermenting gram-negative bacilli (11.76%). Escherichia coli showed yearly resistance to aminoglycosides, cephalosporins, penicillin, fluoroquinolones, and B-lactam combination agents. Routine surveillance and awareness of the prevalence, etiological agents, and antibiotic resistance of gram-negative bacteria causing bacteremia/sepsis is critical for individual therapy, hospital control, and the effectiveness of preventive interventions.

Bloodstream Infections in Patients with Hematologic Diseases: Causative Organisms and Factors Associated with Resistance

Background

Materials and Methods

Results

Conclusion

Bacteriological Profile in Septicaemic Patients with Elevated C-reactive Protein in Intensive Care Units at A Tertiary Care Hospital

Sepsis, the second leading cause of death is due to infections. Intensive care units (ICUs) are having the highest burden of treating the patients with sepsis and nosocomial infections compared to other areas of hospitals. Our objective was to identify the bacteriological profile and their antibiogram of sepsis cases in all ICUs. A sum of 102 blood samples were collected from patients with clinically suspected sepsis with elevated CRP. Processed by an automated method using Bact/Alert & growth were identified by Standard guidelines. Out of 102 samples, 54 (53%) were shown positive by culture. Gram-negative bacilli were the predominant and their number were 33 (61.1% ) and the commonest organisms were from the Enterobacteriaceae family. Escherichia coli was the highest number with 15 (27.7%) followed by Klebsiella pneumoniae 10 (18.51%), & the rest were single isolates of Salmonella typhi, Proteus mirabilis and Citrobacter koseri. Nonfermenter isolated were Acinetobacter baumanii 3 (5.6%), Pseudomonas aeruginosa 2 (3.7%). The Gram-positive cocci were 17 & 32.4% of culture positivity. Coagulase-negative Staphylococcus was the highest isolated accounting for 9 (16.6%) followed by Staphylococcus aureus 6 (11.1%) and Enterococcus faecalis (3.7%). Culture positivity will be more when CRP is also included in the selection of samples for sepsis and Gram-negative bacilli are the leading cause in septicemia and organisms belonging to the Enterobacteriaceae family still dominate in septicemia infections in ICUs and a real challenge for treatment are MDRs which needs to be detected regularly by using screening tests.

Secondary Infections After Diagnosis of Severe Radiation Pneumonitis (SRP) Among Patients With Non-small Cell Lung Cancer: Pathogen Distributions, Choice of Empirical Antibiotics, and the Value of Empirical Antifungal Treatment

PURPOSE

This study aimed to assess pathogen distributions and antimicrobial sensitivity characteristics in patients with non-small cell lung cancer (NSCLC) with severe radiation pneumonitis (SRP) and secondary infections.

METHODS AND MATERIALS

Data from 1746 patients with NSCLC and SRP after thoracic radiation therapy from January 2009 to December 2020 were retrospectively analyzed. Pneumonia incidence, causative pathogens, and antibiotic resistance characteristics in patients with secondary lung infections were analyzed. Risk factors associated with mortality were identified through univariate and multivariate analyses. Antifungal drug efficacy and duration-related effects were assessed with Forest plots and receiver operating characteristic curves.

RESULTS

Overall, 44.5% of patients with NSCLC and SRP (777 of 1746 patients) were diagnosed with secondary lung infections. In total, 899 bacterial strains were isolated from these patients, with Acinetobacter baumannii (n = 206; 27%), Klebsiella pneumonia (n = 200; 26.2%), and Pseudomonas aeruginosa (n = 104; 13.6%) being the most common. Carbapenems and cefoperazone-sulbactam resistance rates of 52.7% and 32.2%, 28.8% and 26.4%, and 23.7% and 20.2% were observed for these isolates, respectively. Infection-related deaths occurred in 22.4% of patients with SRP. Independent risk factors for infection-related death included poor performance status scores, inappropriate empirical antimicrobial treatment, bacteria/fungal coinfection, and lack of empirical antifungal treatment. Receiver operating characteristic curves showed that the cutoff value of empirical antifungal treatment duration was 9 (area under the curve: 0.819).

CONCLUSIONS

For patients with SRP and secondary lung infections, appropriate empirical antimicrobial treatment could decrease infection-related mortality, and cefoperazone-sulbactam may be an appropriate antibacterial drug. Empirical antifungal treatment for a minimum of 9 days might contribute to better outcomes. Although this represents a promising treatment approach for patients with SRP and secondary lung infections before antibacterial susceptibility testing, further prospective validation is essential.

Bloodstream infections in adult patients with malignancy, epidemiology, microbiology, and risk factors associated with mortality and multi-drug resistance

Background

This study aimed to investigate the epidemiology, microbiology, and risk factors associated with mortality and multi-drug resistance bacterial bloodstream infections (BSIs) among adult cancer patients in Shiraz, Iran. We also report a four-year trend of antimicrobial resistance patterns of BSIs.

Methods

We conducted a retrospective study at a referral oncology hospital from July 2015 to August 2019, which included all adults with confirmed BSI.

Results

2393 blood cultures tested during the four-year study period; 414 positive cultures were included. The mean age of our patients was 47.57 ± 17.46 years old. Central Line-Associated BSI (CLABSI) was more common in solid tumors than patients with hematological malignancies. Gram-negative (GN) bacteria were more detected (63.3%, 262) than gram-positive bacteria (36.7%, 152). Escherichia coli was the most common gram-negative organism (123/262, 47%), followed by Pseudomonas spp. (82/262, 31%) and Klebsiella pneumoniae (38/262, 14.5%). Coagulase-negative staphylococci (CoNS) was the most frequently isolated pathogen among gram-positive bacteria (83/152, 54.6%). Acinetobacter spp., Pseudomonas spp., E. coli, and K. pneumoniae were the most common Extended-Spectrum Beta-Lactamase (ESBL) producers (100, 96.2, 66.7%, and 60.7, respectively). Acinetobacter spp., Pseudomonas spp., Enterobacter spp., E. coli, and K. pneumoniae were the most common carbapenem-resistant (CR) isolates (77.8, 70.7, 33.3, 24.4, and 13.2%, respectively). Out of 257 Enterobacterales and non-fermenter gram-negative BSIs, 39.3% (101/257) were carbapenem-resistant. Although the incidence of multi-drug resistance (MDR) gram-negative BSI increased annually during 2015–2018, the mortality rate of gram-negative BSI remains unchanged at about 20% (p-value = 0.55); however, the mortality rate was significantly greater (35.4%) in those with resistant gram-positive BSI (p-value = 0.001). The overall mortality rate was 21.5%. Early (7-day mortality) and late mortality rate (30-day mortality) were 10 and 3.4%, respectively.

Conclusions

The emergence of MDR gram-negative BSI is a significant healthcare problem in oncology centers. The high proportion of the most frequently isolated pathogens were CR and ESBL-producing Enterobacterales and Pseudomonas spp. We have few effective choices against MDRGN BSI, especially in high-risk cancer patients, which necessitate newer treatment options.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12879-021-06243-z.

Investigation of Gram-Negative Bacilli Bacteraemia in a Tertiary Hospital in Nigeria: Epidemiology and Antimicrobial Susceptibility Pattern

Background: The re-emergence of gram-negative bacilli (GNB) as the predominant cause of bacteraemia remains a major concern, given the increasing trend of antimicrobial resistance among this group of organisms. Prompt and effective empirical antibiotic treatment is vital for preventing adverse outcomes; therefore, a good knowledge of the local bacteria profile is required. Objective: This study was designed to aid the establishment of local antibiogram and empirical treatment for GNB bacteremia in patients referred to the University of Port Harcourt Teaching Hospital (UPTH), Nigeria. Materials and Methods: A total of 230 blood samples were obtained from inpatients in different units/departments from December 2017 to November 2018. The blood cultures were processed using BACTEC 9060 automated blood culture system, and the isolates were identified using MICROBACT 12E identification kits (Oxoid, UK) at the microbiology laboratory of UPTH. Susceptibility and resistance tests were done according to CLSI guidelines. Relevant information was obtained from the laboratory request forms and patients’ clinical files. Results: The prevalence of GNB in the study was 28.9% (71/246). The distribution of GNB bacteraemia was as follows: surgical unit (26.8%), special care baby unit (SCBU) (23.9%), intensive care unit (ICU) (21.1%), and paediatric ward (8.5%). The most common source of bacteraemia was pneumonia (35.2%) followed by puerperal sepsis (15.1%) and urinary tract infection (UTI) (15.1%). Klebsiella pneumoniae was the most frequently isolated gram-negative bacillus (26.6%). The overall resistance rate of extended spectrum lactamase producing Enterobacteriaceae (ESBL) producers, carbapenemase producers, and multi-drug resistant (MDR) organisms was 32.4%, with Acinetobacter baumannii (50%) and Pseudomonas aeruginosa (27.3%) exhibiting the highest level of resistance to carbapenems. Conclusion: This study showed a high MDR rate among GNB causing bacteraemia in patients at UPTH. An urgent review of the current antimicrobial prescription policy and infection control measures is recommended.

Direct DNA Sequencing-Based Analysis of Microbiota Associated with Hematological Malignancies in the Eastern Province of Saudi Arabia

Introduction

Bloodstream infections (BSI) among patients with hematological malignancies (HM) could predispose them to higher morbidity and mortality for various underlying conditions. Several microorganisms, either pathogenic or opportunistic normal human flora, could cause severe bacteremia and septicemia. While conventional methods have their own limitations, molecular methods such as next-generation sequencing (NGS) can detect these blood infections with more reliability, specificity, and sensitivity, in addition to information on microbial population landscape. Methodology. Blood samples from HM patients (n = 50) and volunteer blood donor control individuals with no HM (n = 50) were subjected to 16S rRNA gene amplification using standard PCR protocols. A metagenomic library was prepared, and NGS was run on a MiSeq (Illumina) sequencer. Sequence reads were analyzed using MiSeq Reporter, and microbial taxa were aligned using the Green Genes library.

Results

82% of the patients showed BSI with Gram-negative bacteria as the most predominant group. E. coli comprised a major chunk of the bacterial population (19.51%), followed by K. pneumoniae (17.07%). The CoNS and Viridans Streptococci groups are 17.07% and 14.63%, respectively. Other major species were S. aureus (9.75%), P. aeruginosa (7.31%), A. baumannii (4.87%), E. cloacae (4.87%), and P. mirabilis (4.87%). 34.14% of the cases among patients showed a Gram-positive infection, while 14.63% showed polymicrobial infections.

Conclusion

Most of the BSI in patients were characterized by polymicrobial infections, unlike the control samples. Molecular methods like NGS showed robust, fast, and specific identification of infectious agents in BSI in HM, indicating the possibility of its application in routine follow-up of such patients for infections.

Risk factors, antimicrobial susceptibility pattern and patient outcomes of Pseudomonas aeruginosa infection: A matched case-control study

BACKGROUND

Pseudomonas aeruginosa is a leading nosocomial Gram-negative bacteria associated with prolonged hospitalization, and increased morbidity and mortality. Limited data exist regarding P. aeruginosa infection and outcome in patients managed in intensive care units (ICUs) in the Gulf countries. We aimed to determine the risk factors, antimicrobial susceptibility pattern and patient outcomes of P. aeruginosa infection in ICU.

METHODS

In this matched case-control study, all P. aeruginosa infections that occurred >48 h after hospital admission between January 31st 2016 and December 31st 2018 at ICUs affiliated with King Abdulaziz Medical City, Riyadh were included. P. aeruginosa was identified using MALDI-TOF (Vitek-MS) by biomérieux, and the antimicrobial susceptibility testing was performed using an automated biomérieux VITEK^®️ 2 Antimicrobial Susceptibility card.

RESULTS

The study included 90 cases and 90 controls. Compared with controls, cases had significantly higher mean ICU stay and higher proportions with previous history of antimicrobial therapy, coronary artery disease, malignancy, hemodialysis, previous surgery, use of central line, urethral catheterization, nasogastric tube, and tracheostomy. In a multivariate conditional logistic regression analysis, factors independently associated with P. aeruginosa infection were ICU duration [Odds Ratio (OR) 9.05, 95%CI 2.53-32.27, p = .001], previous surgery (OR = 7.33, 95%CI 1.66-32.36, p = .009), tracheostomy (OR = 11.13, 95%CI 1.05-118.59, p = .046), urethral catheterization (OR = 7.38, 95%CI 1.21-45.11, p = .030) and use of aminoglycosides (OR = 10.59, 95%CI 1.14-98.13, p = .038). Approximately 41% of P. aeruginosa isolates were resistant to imipenem, while 36.7% were multidrug-resistant. Mortality was similar in both groups: 54(60%) cases and 51(56.7%) controls; p = .650.

CONCLUSIONS

The study identifies several potentially modifiable factors associated with P. aeruginosa infection in ICUs. Identification of these factors could facilitate case identification and enhance control measures.

Prevalence of antibiotic-resistant organisms among hospitalized patients at a tertiary care center in Lebanon, 2010-2018

BACKGROUND

Infections due to antibiotic resistant organisms (ARO) among hospitalized patients are associated with increased morbidity, mortality, and healthcare costs. Longitudinal data about antimicrobial resistance are scarce in Lebanon and the region. The objective of this study is to describe the temporal trends of resistance of selected pathogens among hospitalized patients at a tertiary care center in Lebanon.

METHODS

We conducted a retrospective review of surveillance data from 2010 until 2018. Six target organisms isolated from hospitalized patients were included: carbapenem-resistant Escherichia coli (CREC), carbapenem-resistant Klebsiella spp. (CRKP), multi-drug resistant Pseudomonas aeruginosa (MDRPA), carbapenem-resistant Acinetobacter baumannii (CRAB), methicillin-resistant Staphylococcus aureus (MRSA), and vancomycin-resistant Enterococcus spp. (VRE). Correlation analysis was performed to evaluate for temporal trends.

RESULTS

A total of 15,901 isolates were examined, most of which were obtained from urinary specimens. Among Gram-negative organisms, the highest resistance was found among CRAB (81.7%), followed by CRKP (6.5%) and CREC (3.3%). MDRPA overall prevalence was 0.8%. Among Gram-positive organisms, the prevalence of MRSA and VRE was 26.2% and 2.6%, respectively. CREC, MRSA, and VRE showed statistically significant increasing temporal trends, while CRAB decreased significantly from 2013 to 2018.

CONCLUSION

These data are helpful in characterizing the epidemiology of antimicrobial resistance in Lebanon and show that controlling emerging resistance is achievable with concerted infection control and antimicrobial stewardship efforts. Caution should be exercised to contain early on the spread of CREC and of resistant Gram-positive pathogens.

Antimicrobial resistance among GLASS pathogens in conflict and non-conflict affected settings in the Middle East: a systematic review

BACKGROUND

In spite of the evident general negative effects of armed conflict on countries' health systems and populations' health outcomes, little is known about similar impacts of conflicts on the spread of antimicrobial resistances (AMR). This review was to address this evidence gap and describe: 1. Patterns of AMR in the Middle East (ME) and resistance profiles of pathogens included in the Global AMR Surveillance System (GLASS) supported by the World Health Organization; 2. Differences in proportions of AMR isolates between conflict and non-conflict countries.

METHODS

A systematic literature review was conducted following PRISMA guidelines and searching five electronic databases. Subject heading and free text were searched for "antimicrobial resistances" and "Middle East", to identify observational studies on AMR published from January 2011 to June 2018. Data were extracted from included articles on a predefined set of variables. Percentages of AMR were analysed as median and interquartile ranges. Risk of bias was assessed using the Newcastle-Ottawa Scale.

RESULTS

A total of 132 articles met the inclusion criteria. Included studies showed heterogeneity in study design, laboratory methods and standards for interpretation of results, and an overall high risk of bias. Main findings were the following: 1. High proportions of carbapenem resistance in Acinetobacter spp. (median 74.2%), and both carbapenem resistance (median 8.1 and 15.4% for E. coli and K. pneumoniae respectively) and ESBL-production (median 32.3 and 27.9% for E. coli and K. pneumoniae respectively) amongst Enterobacteriaceae. S. aureus isolates showed a median methicillin resistance percentage of 45.1%, while vancomycin resistance was almost absent. A median of 50% of the strains of S. pneumoniae showed non-susceptibility to penicillin. 2. Similar trends were observed in conflict and non-conflict affected countries.

CONCLUSIONS

There is a lack of standardization in the methodological approach to AMR research in the Middle East. The proportion of antibiotic resistances among specific GLASS pathogens is high, particularly among Acinetobacter spp.

Colonization with multi-drug-resistant organisms negatively impacts survival in patients with non-small cell lung cancer

Objectives

Multidrug-resistant organisms (MDRO) are considered an emerging threat worldwide. Data covering the clinical impact of MDRO colonization in patients with solid malignancies, however, is widely missing. We sought to determine the impact of MDRO colonization in patients who have been diagnosed with Non-small cell lung cancer (NSCLC) who are at known high-risk for invasive infections.

Materials and methods

Patients who were screened for MDRO colonization within a 90-day period after NSCLC diagnosis of all stages were included in this single-center retrospective study.

Results

Two hundred and ninety-five patients were included of whom 24 patients (8.1%) were screened positive for MDRO colonization (MDRO^pos) at first diagnosis. Enterobacterales were by far the most frequent MDRO detected with a proportion of 79.2% (19/24). MDRO colonization was present across all disease stages and more present in patients with concomitant diabetes mellitus. Median overall survival was significantly inferior in the MDRO^pos study group with a median OS of 7.8 months (95% CI, 0.0–19.9 months) compared to a median OS of 23.9 months (95% CI, 17.6–30.1 months) in the MDRO^neg group in univariate (p = 0.036) and multivariate analysis (P = 0.02). Exploratory analyses suggest a higher rate of non-cancer-related-mortality in MDRO^pos patients compared to MDRO^neg patients (p = 0.002) with an increased rate of fatal infections in MDRO^pos patients (p = 0.0002).

Conclusions

MDRO colonization is an independent risk factor for inferior OS in patients diagnosed with NSCLC due to a higher rate of fatal infections. Empirical antibiotic treatment approaches should cover formerly detected MDR commensals in cases of (suspected) invasive infections.

Management of infections caused by WHO critical priority Gram-negative pathogens in Arab countries of the Middle East: a consensus paper

Antimicrobial resistance is an important global issue that impacts the efficacy of established antimicrobial therapy. This is true globally and within the Arab countries of the Middle East, where a range of key Gram-negative pathogens pose challenges to effective therapy. There is a need to establish effective treatment recommendations for this region given specific challenges to antimicrobial therapy, including variations in the availability of antimicrobials, infrastructure and specialist expertise. This consensus provides regional recommendations for the first-line treatment of hospitalized patients with serious infections caused by World Health Organization critical priority Gram-negative pathogens Acinetobacter baumannii and Pseudomonas aeruginosa resistant to carbapenems, and Enterobacteriaceae resistant to carbapenems and third-generation cephalosporins. A working group comprising experts in infectious disease across the region was assembled to review contemporary literature and provide additional consensus on the treatment of key pathogens. Detailed therapeutic recommendations are formulated for these pathogens with a focus on bacteraemia, nosocomial pneumonia, urinary tract infections, skin and soft tissue infections, and intra-abdominal infections. First-line treatment options are provided, along with alternative agents that may be used where variations in antimicrobial availability exist or where local preferences and resistance patterns should be considered. These recommendations take into consideration the diverse social and healthcare structures of the Arab countries of the Middle East, meeting a need that is not filled by international guidelines. There is a need for these recommendations to be updated continually to reflect changes in antimicrobial resistance in the region, as well as drug availability and emerging data from clinical trials.

Impact of Catheter Management on Clinical Outcome in Adult Cancer Patients With Gram-Negative Bacteremia

Objective

Gram-negative organisms have become a major etiology of bloodstream infections. We evaluated the effect of central venous catheter management on cancer patients with gram-negative bloodstream infections.

Method

We retrospectively identified patients older than 14 years with central venous catheters who were diagnosed with gram-negative bloodstream infections to determine the effect of catheter management on outcome. Patients were divided into 3 groups: Group 1 included patients with central line-associated bloodstream infections (CLABSI) without mucosal barrier injury and those whose infection met the criteria for catheter-related bloodstream infection; group 2 included patients with CLABSI with mucosal barrier injury who did not meet the criteria for catheter-related bloodstream infection; and group 3 included patients with non-CLABSI.

Results

The study included 300 patients, with 100 patients in each group. Only in group 1 was central venous catheter removal within 2 days of bloodstream infection significantly associated with a higher rate of microbiologic resolution at 4 days compared to delayed central venous catheter removal (3–5 days) or retention (98% vs 82%, P = .006) and a lower overall mortality rate at 3-month follow-up (3% vs 19%, P = .01). Both associations persisted in multivariate analyses (P = .018 and P = .016, respectively).

Conclusions

Central venous catheter removal within 2 days of the onset of gram-negative bloodstream infections significantly improved the infectious outcome and overall mortality of adult cancer patients with catheter-related bloodstream infections and CLABSI without mucosal barrier injury.

Role of outer membrane permeability, efflux mechanism, and carbapenemases in carbapenem-nonsusceptible Pseudomonas aeruginosa from Dubai hospitals: Results of the first cross-sectional survey

OBJECTIVES

Carbapenem resistance in Pseudomonas aeruginosa is growing and results from variable mechanisms. The objectives of the current study were to investigate mechanisms of carbapenem resistance and genetic relatedness of P. aeruginosa isolates recovered in Dubai hospitals.

METHODS

From June 2015 through June 2016, carbapenem-nonsusceptible P. aeruginosa were collected from 4 hospitals in Dubai, and subjected to antimicrobial susceptibility testing, molecular investigation of carbapenemases by PCR-sequencing, analysis of outer membrane porin OprD2 and multidrug efflux channel MexAB-OprM levels by qPCR, and fingerprinting by ERIC-PCR.

RESULTS

Out of 1969 P. aeruginosa isolated during the study period, 471 (23.9%) showed reduced carbapenem susceptibility. Of these, 37 were analyzed and 32% of them produced VIM-type metallo-β-lactamases, including VIM-2, VIM-30, VIM-31, and VIM-42, while GES-5 and GES-9 co-existed with VIM in 5.4% of isolates. Outer membrane impermeability was observed in 73% of isolates and 75.6% displayed overproduced MexAB-OprM. ERIC-PCR revealed one large clone including most carbapenemase-producing isolates indicating clonal dissemination.

CONCLUSION

This is the first study on carbapenem-nonsusceptible P. aeruginosa from Dubai, incriminating VIM production as well as outer membrane permeability and efflux systems as resistance mechanisms. Further studies on carbapenem-nonsusceptible P. aeruginosa in Dubai are warranted for containment of such health hazard.

Prevalence of Acinetobacter baumannii in Saudi Arabia: risk factors, antimicrobial resistance patterns and mechanisms of carbapenem resistance

Acinetobacter baumannii is an important opportunistic pathogen due to its capabilities for developing mechanisms of resistance to a wide range of antimicrobial agents including carbapenems. This review described the risk factors, antimicrobial susceptibility and mechanisms of carbapenem resistance of A. baumannii from different geographical regions of Saudi Arabia. Several factors including complexity of intensive care unit (ICU) environments, increased numbers of patients with serious diseases, wide spread gastrointestinal colonization and extensive use of antimicrobial drugs led to a wide prevalence of A. baumannii infections in hospitals in Saudi Arabia. A. baumannii has been noted to be less susceptible to antimicrobials agents, including carbapenems, over time, resulting in the evolution of multidrug-resistant (MDR) strains. Dissemination of MDR A. baumannii is attributed to the extreme use of wide-spectrum antimicrobial drugs in hospitals, cross infection between inpatients, invasive ICU procedures, and hospitalized patients with diabetic and cancer those are under frequent invasive diagnostic and therapeutic interventions. Although an increasing prevalence of colistin and tigecycline resistance has been reported in many hospitals, combinations of these agents with carbapenems or other antibiotics remain the best therapeutic choice and reasonably safe to treat patients with MDR A. baumannii infections. The wide distribution of carbapenem resistant A. baumannii (CRAB) due to several mechanisms with diverse genetic determinants has been documented. Although OXA-23 β-lactamase and OXA-51 β-lactamase are the most common genes responsible for CRAB, other novel genes such as blaVIM, PER-1-like and GES-5 have been discovered in carbapenem resistant strains. The high rates of MDR A. baumannii in Saudi hospitals indicate that extensive investigation into the molecular basis of MDR and developing new therapies of CRAB is needed. Moreover, the development of a local antibiogram database coupled with a nationwide antimicrobial stewardship and infection prevention program might help to improve our knowledge of the resistance patterns of A. baumannii, and in developing a treatment protocol for decreasing the infection burden in Saudi Arabia.

Epidemiology of common resistant bacterial pathogens in the countries of the Arab League

No uniformly organised collection of data regarding antimicrobial resistance has occurred in the countries of the Arab League. 19 countries of the Arab League have published data for antimicrobial susceptibility for the WHO priority organisms, and seven of 14 of these organisms are included in this Review (Escherichia coli, Klebsiella spp, Pseudomonas aeruginosa, Acinetobacter baumannii, Salmonella spp, Staphylococcus aureus, and Streptococcus pneumoniae). Although E coli and Klebsiella spp resistance to third-generation cephalosporins is common in all countries, with prevalence reaching more than 50% in Egypt and Syria, carbapenem resistance is emerging, albeit with a prevalence of less than 10%. Conversely, a large amount of carbapenem resistance has been reported for P aeruginosa and A baumannii across the Arab League, reaching 50% and 88% of isolates in some countries. As for Salmonella spp, the prevalence of fluoroquinolone resistance has exceeded 30% in several areas. With regards to the Gram-positive pathogens, the prevalence of meticillin resistance in S aureus is reported to be between 20% and 30% in most countries, but exceeds 60% in Egypt and Iraq. The prevalence of penicillin non-susceptibility among pneumococci has reached more than 20% in Algeria, Egypt, Morocco, Saudi Arabia, and Tunisia. These findings highlight the need for structured national plans in the region to target infection prevention and antimicrobial stewardship.