Case-control analysis of endemic Acinetobacter baumannii bacteremia in the neonatal intensive care unit

Prevalence of biofilm producing Acinetobacter baumannii clinical isolates: A systematic review and meta-analysis

BACKGROUND

Acinetobacter baumannii, the first human pathogen to be designated as a "red-alert" pathogen, is on the critical priority list of pathogens requiring new antibiotics. Biofilm-associated diseases are the most common infections caused by the antibiotic-resistant bacteria A. baumannii. Multidrug-resistant strains are more easily transmitted around the world due to A. baumannii's ability to produce biofilms, which allows it to develop antibiotic resistance mechanisms and thrive in healthcare environments. As a result, A. baumannii infections are becoming increasingly common in hospital settings allover the world. As a result, a comprehensive systematic review and meta-analysis were carried out to determine the global prevalence of biofilm-producing A. baumannii clinical isolates.

METHODS

Articles were extensively searched in bibliographic databases and grey literatures using entry terms or phrases. Studies meeting eligibility criteria were extracted in MS Excel and exported into STATA version 12 software for statistical analysis. A random-effects model was used to compute the pooled prevalence of biofilm-producing A. baumannii clinical isolates. The heterogeneity was quantified by using the I2 value. Publication bias was assessed using a funnel plot and Egger's test. Sensitivity analysis was done to assess the impact of a single study on pooled effect size.

RESULT

Of the 862 studies identified, 26 studies consisted of 2123 A.baumannii clinical isolates of which 1456 were biofilm-producing. The pooled prevalence of biofilm-producing A.baumannii clinical isolates was 65.63% (95% CI = 56.70%-74.56%). There was substantial heterogeneity with an I2 value of 98.1%. Moreover, 41.34%, 33.57%, and 27.63% of isolates of strong, mild, and weak producers of biofilm. Higher prevalence was found in studies published after 2014 (66.31%); Western Pacific region (76.17%); and Asia (66.22%) followed by the African continent (57.29%).

CONCLUSION

The pooled prevalence of biofilm-producing A. baumannii clinical isolates has risen alarmingly, posing a public health risk. This indicates the burden of biofilm-producing A. baumannii infections urges routine screening and appropriate treatment for better management of hospitalized patients, as well as effective controlling of the emergence of drug resistance. Furthermore, this finding is an alert call for the stakeholders to develop strong infection prevention and antibiotics stewardship programs for the prevention and control of biofilm-producing bacterial infections.

Risk Factors for 30-Day Mortality in Neonates With Carbapenem-resistant A. baumannii Sepsis

BACKGROUND

Carbapenem-resistant Acinetobacter baumannii (CRAB) sepsis is becoming an extreme threat caused by high-case fatality rates and poor prevention and control in ICUs worldwide. However, the risk of mortality among neonatal CRAB sepsis is still unclear.

METHODS

A retrospective medical records review study, which aimed to identify the risk factors of mortality in neonates with CRAB sepsis (including both bacteremia and/or meningitis) in Thailand from 1996 to 2019. All cases featuring positive blood and cerebrospinal fluid cultures for CRAB were reviewed. A multivariable logistic regression model was analyzed for nonsurvivors and survivors of neonatal CRAB sepsis.

RESULTS

In a 24-year period, 47 of these were identified with CRAB sepsis. The median (interquartile range) gestational age and birth weight were 30 (28-35) weeks and 1500 (933-2482) g, respectively. The 30-day case fatality rate was 55% (26/47). In multivariable analysis, nonsurvivors of neonatal CRAB sepsis were associated with congenital heart disease (adjusted odds ratio [OR] = 1.33; 95% CI 1.06-1.66, P = 0.02), CRIB II score ≥9 (adjusted OR = 1.65; 95% CI: 1.20-2.27, P = 0.004), severe thrombocytopenia (adjusted OR = 1.45; 95% CI: 1.09-1.94, P = 0.02), and septic shock (adjusted OR = 1.62; 95% CI: 1.33-1.99, P <0.001).

CONCLUSION

The risk factors of mortality in neonates with CRAB sepsis are associated with congenital heart disease, CRIB II score ≥9, shock, and severe thrombocytopenia.

Relationship Between COVID-19 Lockdown and Epidemiology of Neonatal Sepsis

BACKGROUND

We compared the hospital-based epidemiology of neonatal sepsis after the coronavirus disease 2019 lockdown (LD) versus historical epochs and the LD period versus phases of unlocking.

METHODS

This retrospective cohort study was conducted in a level 3 neonatal unit. We compared neonates born in three 24-week periods-Group LD: 22 March 2020 to 5 September 2020-the reference group, Group pre-LD: 29 September 2019 to 14 March 2020 and Group temporally corresponding to LD in 2019 (corres-LD): 24 March 2019 to 7 September 2019. We also studied linear trends from LD phase 1.0 until Unlock 4.0. The key outcome was culture-positive sepsis.

RESULTS

There were 1622, 2744 and 2700 subjects in groups LD, pre-LD and corres-LD, respectively. The incidence of any culture-positive sepsis in pre-LD was higher than LD [odds ratio (95% CI) = 1.61 (1.02-2.56)]. This was mainly due to a statistically significant reduction in Acinetobacter baumannii sepsis, with incidence rate differences of pre-LD versus LD [0.67 (95% CI: 0.37-0.97), P = 0.0001] and corres-LD versus LD [0.40 (95% CI: 0.16-0.64), P = 0.0024]. Groups pre-LD and corres-LD had higher proportion of multi-drug resistant (MDR)/extreme drug resistance/pan drug resistance sepsis than LD [77%, 77% and 44%, respectively (P values of both groups vs. LD = 0.01)]. From LD 1.0 to unlock 4.0, there were fewer episodes of MDR sepsis (Plinear trends = 0.047). On multivariable analysis, group pre-LD (vs. reference group LD), male sex, birth weight and Apgar score independently predicted culture-positive sepsis.

CONCLUSIONS

LD favorably impacted the epidemiology of neonatal sepsis in a hospital setting, with less A. baumannii and MDR sepsis, which persisted during unlocking.

Infections Due to Acinetobacter baumannii-calcoaceticus Complex: Escalation of Antimicrobial Resistance and Evolving Treatment Options

Bacteria within the genus Acinetobacter (principally A. baumannii-calcoaceticus complex [ABC]) are gram-negative coccobacilli that most often cause infections in nosocomial settings. Community-acquired infections are rare, but may occur in patients with comorbidities, advanced age, diabetes mellitus, chronic lung or renal disease, malignancy, or impaired immunity. Most common sites of infections include blood stream, skin/soft-tissue/surgical wounds, ventilator-associated pneumonia, orthopaedic or neurosurgical procedures, and urinary tract. Acinetobacter species are intrinsically resistant to multiple antimicrobials, and have a remarkable ability to acquire new resistance determinants via plasmids, transposons, integrons, and resistance islands. Since the 1990s, antimicrobial resistance (AMR) has escalated dramatically among ABC. Global spread of multidrug-resistant (MDR)-ABC strains reflects dissemination of a few clones between hospitals, geographic regions, and continents; excessive antibiotic use amplifies this spread. Many isolates are resistant to all antimicrobials except colistimethate sodium and tetracyclines (minocycline or tigecycline); some infections are untreatable with existing antimicrobial agents. AMR poses a serious threat to effectively treat or prevent ABC infections. Strategies to curtail environmental colonization with MDR-ABC require aggressive infection-control efforts and cohorting of infected patients. Thoughtful antibiotic strategies are essential to limit the spread of MDR-ABC. Optimal therapy will likely require combination antimicrobial therapy with existing antibiotics as well as development of novel antibiotic classes.

Nonfermenting, Gram-Negative Bacilli Causing Neonatal Sepsis in Odisha, India: Four-Year Surveillance

Introduction

In India, blood culture-positive sepsis results in mortality in 33%-35% of affected neonates. Nonfermenting Gram-negative bacilli (NFGNB), particularly Acinetobacter baumannii and Burkholderia cepacia commonly cause hospital-acquired infection.

Materials and methods

We performed a subgroup analysis as part of a prospective study conducted in a neonatal intensive care unit in a tertiary care hospital in Odisha, India, between January 2017 and December 2020. Neonates with blood culture-positive sepsis caused by NFGNB were enrolled in this study. Demographic characteristics of the neonates, clinical features of sepsis, complications, need for supportive care, and blood culture sensitivity patterns were recorded and analyzed.

Results

A total of 168 organisms were isolated in blood cultures during our study period, of which 48 (29%) were NFGNB species. Among these 48 species, A. baumannii (37.5%) and B. cepacia (33.3%) were the most common NFGNB in our study. Neonates with sepsis commonly exhibited feeding intolerance (64.5%), circulatory insufficiency that necessitated vasopressor treatment (54.1%), disseminated intravascular coagulopathy (35.4%), seizures (33.3%), and the need for respiratory support (56.2%). NFGNB were multidrug-resistant (MDR) in 70.8% of cases, and 93.7% of B. cepacia and 55.5% of A. baumannii were MDR.

Conclusions

A. baumannii and B. cepacia are NFGNB commonly isolated in neonatal cases of blood culture-positive sepsis. The prevalence of MDR NFGNB sepsis is gradually increasing, which poses a threat to neonates. Strict aseptic precautions and antibiotic stewardship are thus mandatory in perinatal practice.

Multidrug-resistant Acinetobacter baumannii outbreaks: a global problem in healthcare settings

INTRODUCTION

The increase in the prevalence of multidrug-resistant Acinetobacter baumannii infections in hospital settings has rapidly emerged worldwide as a serious health problem.

METHODS

This review synthetizes the epidemiology of multidrug-resistant A. baumannii, highlighting resistance mechanisms.

CONCLUSIONS

Understanding the genetic mechanisms of resistance as well as the associated risk factors is critical to develop and implement adequate measures to control and prevent acquisition of nosocomial infections, especially in an intensive care unit setting.

Potential of Minimally Invasive Tissue Sampling for Attributing Specific Causes of Childhood Deaths in South Africa: A Pilot, Epidemiological Study

BACKGROUND

Current estimates for causes of childhood deaths are mainly premised on modeling of vital registration and limited verbal autopsy data and generally only characterize the underlying cause of death (CoD). We investigated the potential of minimally invasive tissue sampling (MITS) for ascertaining the underlying and immediate CoD in children 1 month to 14 years of age.

METHODS

MITS included postmortem tissue biopsies of brain, liver, and lung for histopathology examination; microbial culture of blood, cerebrospinal fluid (CSF), liver, and lung samples; and molecular microbial testing on blood, CSF, lung, and rectal swabs. Each case was individually adjudicated for underlying, antecedent, and immediate CoD by an international multidisciplinary team of medical experts and coded using the International Classification of Diseases, Tenth Revision (ICD-10).

RESULTS

An underlying CoD was determined for 99% of 127 cases, leading causes being congenital malformations (18.9%), complications of prematurity (14.2%), human immunodeficiency virus/AIDS (12.6%), diarrheal disease (8.7%), acute respiratory infections (7.9%), injuries (7.9%), and malignancies (7.1%). The main immediate CoD was pneumonia, sepsis, and diarrhea in 33.9%, 19.7%, and 10.2% of cases, respectively. Infection-related deaths were either an underlying or immediate CoD in 78.0% of cases. Community-acquired pneumonia deaths (n = 32) were attributed to respiratory syncytial virus (21.9%), Pneumocystis jirovecii (18.8%), cytomegalovirus (15.6%), Klebsiella pneumoniae (15.6%), and Streptococcus pneumoniae (12.5%). Seventy-one percent of 24 sepsis deaths were hospital-acquired, mainly due to Acinetobacter baumannii (47.1%) and K. pneumoniae (35.3%). Sixty-two percent of cases were malnourished.

CONCLUSIONS

MITS, coupled with antemortem clinical information, provides detailed insight into causes of childhood deaths that could be informative for prioritization of strategies aimed at reducing under-5 mortality.

Emergence of antimicrobial resistance among Acinetobacter species: a global threat

PURPOSE OF REVIEW

Bacteria within the genus Acinetobacter [principally Acinetobacter baumannii-calcoaceticus complex (ABC)] are Gram-negative coccobacilli that may cause serious nosocomial infections (particularly ventilator-associated pneumonia and infections of the bloodstream, urinary tract, and wounds) as well as community-acquired infections (often skin/soft tissue infections in the context of trauma). Within the past two decades, Acinetobacter spp. have been responsible for an increasing number of infections in intensive care units (ICUs) globally. Treatment of Acinetobacter infections is difficult, as Acinetobacter spp. are intrinsically resistant to multiple antimicrobial agents, and have a remarkable ability to acquire new resistance determinants via multiple mechanisms.

RECENT FINDINGS

Since the 1990s, global resistance to antimicrobials has escalated dramatically among ABC. Global spread of multidrug-resistant (MDR) A. baumannii strains reflects dissemination of a few clones between hospitals, geographic regions, and continents; this spread is amplified by excessive use of antibiotics. Many isolates are resistant to all antimicrobials except colistin (polymyxin E), and some infections are untreatable with existing antimicrobial agents.

SUMMARY

Antimicrobial resistance poses a serious threat to control infections due to ABC. Strategies to curtail environmental colonization with MDR-ABD will require aggressive infection control efforts and cohorting of infected patients. Thoughtful antibiotic strategies are essential to limit the consequences and spread of MDR-ABC. Optimal therapy will likely require combination antimicrobial therapy of existing antibiotics as well as development of novel antibiotic classes.

Risk factors and molecular epidemiology of Acinetobacter baumannii bacteremia in neonates

BACKGROUND

Acinetobacter baumannii infections in neonates are not uncommon but rarely studied.

METHODS

Clinical and molecular epidemiology of 40 patients with A. baumannii bacteremia in the neonatal intensive care units (NICUs) of a medical center from 2004 to 2014 was analyzed.

RESULTS

Multi-drug resistance was found in only 3 isolates (7.5%). Sequence types (STs) of A. baumannii defined by multilocus sequencing typing were diverse, and 72.4% identified isolates belonged to novel STs. Majority of the isolates were susceptible to antibiotics tested. Among the 3 imipenem-resistant A. baumannii (IRAB) isolates, 2 (66.7%) belonged to ST684, a novel ST. All of the 3 isolates were susceptible to tigecycline and colistin. The predominant mechanism of imipenem resistance in these neonatal isolates is ISAba1-bla_OXA-80, which has never been reported in Asia before. Most infected newborns were premature (95%), with very low birth weight (70% < 1500 g), prolonged intubation, usage of percutaneous central venous catheter (65%) and long-term usage of total parenteral nutrition or intravenous lipid (95%). IRAB infection, inappropriate initial therapy, 1-minute Apgar score and early onset infection within the first 10 days of life were found to correlate with mortality by log-rank test. Prior use of imipenem for at least 5 days and use of high frequency oscillation ventilation (HFOV) were statistically significant risk factors for acquiring IRAB infections.

CONCLUSIONS

To reduce mortality of IRAB infection, it is crucial to consider giving effective agents, such as colistin, in 2 days for high risk neonates who has been given imipenem or used HFOV.

The Increasing Challenge of Multidrug-Resistant Gram-Negative Bacilli: Results of a 5-Year Active Surveillance Program in a Neonatal Intensive Care Unit

Colonization and infection by multidrug-resistant gram-negative bacilli (MDR GNB) in neonatal intensive care units (NICUs) are increasingly reported.We conducted a 5-year prospective cohort surveillance study in a tertiary NICU of the hospital "Paolo Giaccone," Palermo, Italy. Our objectives were to describe incidence and trends of MDR GNB colonization and the characteristics of the most prevalent organisms and to identify the risk factors for colonization. Demographic, clinical, and microbiological data were prospectively collected. Active surveillance cultures (ASCs) were obtained weekly. Clusters of colonization by extended spectrum β-lactamase (ESBL) producing Escherichia coli and Klebsiella pneumoniae were analyzed by conventional and molecular epidemiological tools.During the study period, 1152 infants were enrolled in the study. Prevalences of colonization by MDR GNB, ESBL-producing GNB and multiple species/genera averaged, respectively, 28.8%, 11.7%, and 3.7%. Prevalence and incidence density of colonization by MDR GNB and ESBL-producing GNB showed an upward trend through the surveillance period. Rates of ESBL-producing E coli and K pneumoniae colonization showed wide fluctuations peaking over the last 2 years. The only independent variables associated with colonization by MDR GNB and ESBL-producing organisms and multiple colonization were, respectively, the days of NICU stay (odds ratio [OR] 1.041), the days of exposure to ampicillin-sulbactam (OR 1.040), and the days of formula feeding (OR 1.031). Most clusters of E coli and K pneumoniae colonization were associated with different lineages. Ten out of 12 clusters had an outborn infant as their index case.Our study confirms that MDR GNB are an increasing challenge to NICUs. The universal once-a-week approach allowed us to understand the epidemiology of MDR GNB, to timely detect new clones and institute contact precautions, and to assess risk factors. Collection of these data can be an important tool to optimize antimicrobials use and control the emergence and dissemination of resistances in NICU.

Multidrug-resistant Acinetobacter baumannii infection among neonates in a neonatal intensive care unit at a medical center in central Taiwan

BACKGROUND

Few studies have focused on multidrug-resistant Acinetobacter baumannii (MDRAB) infection in neonates. The aim of this study was to investigate risk factors for mortality in neonates with MDRAB infection.

METHODS

This retrospective case-series study was conducted at the Children's Hospital of China Medical University, Taichung, Taiwan. All patients hospitalized between January 2010 and December 2013 in the neonatal intensive care unit (NICU) with MDRAB infections were reviewed.

RESULTS

A total of 67 isolates from 59 neonatal patients were positive for MDRAB. Of the 67 isolates, 38 were from blood (56.72%), 16 from sputum (23.88%), seven from pus (10.45%), three from ascites (4.48%), two from cerebrospinal fluid (2.99%), and one from pleural fluid (1.49%). There were five episodes of MDRAB clusters consisting of 28 cases during the study period. The mortality rate due to MDRAB sepsis was 20.34% (12/59). The statistically significant risk factors for mortality due to MDRAB infection were being infected with MDRAB within 7 days of admission to the NICU, use of umbilical vein catheters, absolute neutrophil count < 1500/mm(3), platelet count < 100,000/mm(3), and a delay in initiating adequate antibiotic treatment.

CONCLUSION

MDRAB infection is responsible for a high mortality rate among neonates in the NICU, especially in those who have neutropenia or thrombocytopenia. Infection control and appropriateness of the initial antimicrobial agent with colistin play an important role in reducing mortality.