Carbapenem resistant Gram-negative bacteremia in an Indian intensive care unit: A review of the clinical profile and treatment outcome of 50 patients

Clinical Utility of Blood Culture Identification 2 Panel in Flagged Blood Culture Samples from the Intensive Care Unit of a Tertiary Care Hospital

Background

The availability of rapid diagnostic platforms for positive blood cultures has accelerated the speed at which the clinical microbiology laboratory can identify the causative organism and facilitate early appropriate antimicrobial therapy. There is a paucity of data regarding the clinical utility of the blood culture identification 2 (BCID2) panel test and its correlation with phenotypic drug susceptibility testing (DST) in flagged blood culture bottles from intensive care units (ICUs) in countries such as India, which have high rates of multidrug-resistant gram-negative bacteria (MDR-GNB).

Materials and methods

We conducted a retrospective observational study in a tertiary care ICU on 200 patients above 18 years of age in whom a BCID2 test was ordered when blood cultures flagged positive.

Results

We found 99% concordance between BCID2 and cultures in the identification of bacteria and yeasts and 96.5% concordance between phenotypic and genotypic DST. Furthermore, BCID2 was available about 1.5 days earlier than conventional ID and DST and played a key role in tailoring antimicrobials in 82.5% of the patients. Polymyxin-based therapy was discontinued earlier after an empiric dose in 138 patients (69%) based on BCID2 reports.

Conclusion

In critically ill patients with monomicrobial bacteremia, BCID2 rapidly identifies bacteria and antimicrobial resistance (AMR) genes and is significantly faster than conventional culture and sensitivity testing. Antibiotics were escalated in more than a third of patients and de-escalated in almost a fifth on the same day. We recommend that all ICUs routinely incorporate the test in their antibiotic decision-making process and in antimicrobial stewardship.

How to cite this article

Vineeth VK, Nambi PS, Gopalakrishnan R, Sethuraman N, Ramanathan Y, Chandran C, et al. Clinical Utility of Blood Culture Identification 2 Panel in Flagged Blood Culture Samples from the Intensive Care Unit of a Tertiary Care Hospital. Indian J Crit Care Med 2024;28(5):461-466.

Polymyxin combination therapy for multidrug-resistant, extensively-drug resistant, and difficult-to-treat drug-resistant gram-negative infections: is it superior to polymyxin monotherapy?

INTRODUCTION

The increasing prevalence of infections with multidrug-resistant (MDR), extensively-drug resistant (XDR) or difficult-to-treat drug resistant (DTR) Gram-negative bacilli (GNB), including Pseudomonas aeruginosa, Acinetobacter baumannii, Klebsiella pneumoniae, Enterobacter species, and Escherichia coli poses a severe challenge.

AREAS COVERED

The rapid growing of multi-resistant GNB as well as the considerable deceleration in development of new anti-infective agents have made polymyxins (e.g. polymyxin B and colistin) a mainstay in clinical practices as either monotherapy or combination therapy. However, whether the polymyxin-based combinations lead to better outcomes remains unknown. This review mainly focuses on the effect of polymyxin combination therapy versus monotherapy on treating GNB-related infections. We also provide several factors in designing studies and their impact on optimizing polymyxin combinations.

EXPERT OPINION

An abundance of recent in vitro and preclinical in vivo data suggest clinical benefit for polymyxin-drug combination therapies, especially colistin plus meropenem and colistin plus rifampicin, with synergistic killing against MDR, XDR, and DTR P. aeruginosa, K. pneumoniae and A. baumannii. The beneficial effects of polymyxin-drug combinations (e.g. colistin or polymyxin B + carbapenem against carbapenem-resistant K. pneumoniae and carbapenem-resistant A. baumannii, polymyxin B + carbapenem + rifampin against carbapenem-resistant K. pneumoniae, and colistin + ceftolozan/tazobactam + rifampin against PDR-P. aeruginosa) have often been shown in clinical setting by retrospective studies. However, high-certainty evidence from large randomized controlled trials is necessary. These clinical trials should incorporate careful attention to patient's sample size, characteristics of patient's groups, PK/PD relationships and dosing, rapid detection of resistance, MIC determinations, and therapeutic drug monitoring.

Evaluation of in-vitro colistin susceptibility and clinical profile of carbapenem resistant Enterobacteriaceae related invasive infections

PURPOSE

To determine the colistin susceptibility. To compare E-test vs broth-microdilution (BMD) method for invasive carbapenem resistant Enterobacteriaceae (CRE) infections. To study treatment options for the CRE. To analyze the clinical profile and outcome of CRE infections.

METHODS

Antimicrobial susceptibility testing was performed for 100 invasive CRE isolates. Gradient diffusion and BMD methods were performed to determine colistin MICs. Essential agreement (EA), categorical agreement (CA), very major error (VME), and major error (ME) were worked out between BMD method and E-test. The clinical profile of patients was analyzed.

RESULTS

The majority of the patients suffered from bacteremia [47(47%)]. Klebsiella pneumoniae was the most common organism isolated overall as well as among bacteremic isolates. 9(9%) CRE isolates were colistin resistant by BMD of which six were Klebsiella pneumoniae. There was 97% CA between E-test and BMD. EA was 68%. VME was found in three out of nine colistin resistant isolates. No ME was found. Among the other antibiotics tested for CRE isolates, the highest susceptibility was seen to tigecycline [43(43%)] followed by amikacin [19 (19%)]. The most common underlying condition was post solid organ transplantation [36(36%)]. A higher survival rate was seen among non-bacteremic CRE infections (58.49%) than bacteremic CRE infections (42.6%). Four out of nine patients with colistin resistant CRE infections survived and had a satisfactory outcome.

CONCLUSION

Klebsiella pneumoniae was the most common organism causing invasive infection. Survival rates were higher in non-bacteremic CRE infections than bacteremic infections. Good CA was seen between E-test and BMD for colistin susceptibility, but the EA was poor. VME was more common than ME when E-tests were used for colistin susceptibility testing resulting in false susceptibility. Tigecycline and aminoglycosides are possible adjunct drugs for the treatment of invasive CRE infections.

Prevalence of polymyxin-induced nephrotoxicity and its predictors in critically ill adult patients: A meta-analysis

BACKGROUND

Polymyxin-induced nephrotoxicity is a major safety concern in clinical practice due to long-term adverse outcomes and high mortality.

AIM

To conducted a systematic review and meta-analysis of the prevalence and potential predictors of polymyxin-induced nephrotoxicity in adult intensive care unit (ICU) patients.

METHODS

PubMed, EMBASE, the Cochrane Library and Reference Citation Analysis database were searched for relevant studies from inception through May 30, 2022. The pooled prevalence of polymyxin-induced nephrotoxicity and pooled risk ratios of associated factors were analysed using a random-effects or fixed-effects model by Stata SE ver. 12.1. Additionally, subgroup analyses and meta-regression were conducted to assess heterogeneity.

RESULTS

A total of 89 studies involving 12234 critically ill adult patients were included in the meta-analysis. The overall pooled incidence of polymyxin-induced nephrotoxicity was 34.8%. The pooled prevalence of colistin-induced nephrotoxicity was not higher than that of polymyxin B (PMB)-induced nephrotoxicity. The subgroup analyses showed that nephrotoxicity was significantly associated with dosing interval, nephrotoxicity criteria, age, publication year, study quality and sample size, which were confirmed in the univariable meta-regression analysis. Nephrotoxicity was significantly increased when the total daily dose was divided into 2 doses but not 3 or 4 doses. Furthermore, older age, the presence of sepsis or septic shock, hypoalbuminemia, and concomitant vancomycin or vasopressor use were independent risk factors for polymyxin-induced nephrotoxicity, while an elevated baseline glomerular filtration rate was a protective factor against colistin-induced nephrotoxicity.

CONCLUSION

Our findings indicated that the incidence of polymyxin-induced nephrotoxicity among ICU patients was high. It emphasizes the importance of additional efforts to manage ICU patients receiving polymyxins to decrease the risk of adverse outcomes.

Optimal dosing interval of intravenous Colistin monotherapy versus combination therapy: A systematic review and meta-analysis

We aimed to maximize the clinical response and effectiveness of colistin antibiotics in patients with multi-drug (MDR) and extensively drug-resistant (XDR) Gram-negative bacteria, there is an increasing interest in colistin combination therapy with other antibiotics and extended interval dosing regimens. This systematic review and meta-analysis aim is to evaluate if the combination therapy is superior to monotherapy with colistin regarding increased survival and also which dose interval is the most effective to utilize. English language, peer-reviewed journal publications from the first date available to 25 January 2022 were identified by searching the PubMed and Web of Science databases. Forest plots for overall and subgroups and funnel plots were graphed. 42 studies were included in the study. Among them, 38 studies were on combination therapy, and four on dose interval. The overall pooled odds ratio is 0.77 (CI: 0.62; 0.95) (p value < 0.017). The I^2 value was 43% (p value < 0.01). The Begg correlation test of funnel plot asymmetry showed no significant publication bias (0.064). The overall pooled odds ratio for Carbapenem is 0.74 (CI: 0.48; 1.13). A prospective randomized controlled trials (RCT) on 40 adults intensive care unit (ICU) patients with ventilator-associated pneumonia (VAP), comparing the mortality and ICU length of stay of 8- or 24- hour intervals regimens, showed that the ICU length of stay and ICU mortality were; 31.31, 35.3 days, and 32.06, 22.2% in groups 24-h interval and 8- hour interval (p value: 0.39, 0.87), respectively. It seems that combination therapy is associated with drug synergism and increased survival. The extended interval colistin administration may result in higher peak concentration and bacterial eradication. In both cases, we face a dearth of literature.

Impact of Adding Rapid Polymerase Chain Reaction-based Blood Culture Identification Panel to Antimicrobial Stewardship Program: Initial Experience

How to cite this article: Arjun R, Niyas VKM, John KE, Nair A, Hussain F. Impact of Adding Rapid Polymerase Chain Reaction-based Blood Culture Identification Panel to Antimicrobial Stewardship Program: Initial Experience. Indian J Crit Care Med 2022;26(10):1155-1157.

Molecular Detection of Carbapenemase Enzymes Directly from Positive Blood Cultures Using Xpert Carba-R

Objective  The performance of Xpert Carba-R assay for the direct identification of carbapenemases directly from positive blood culture vials was evaluated.

Materials and Methods  In total, 176 positively flagged blood culture vials, yielding carbapenem-resistant GNB (CR-GNB), were enrolled for the detection and differentiation of blaKPC, blaNDM, blaVIM, blaOXA-48, and blaIMP using Xpert Carba-R.

Results   Klebsiella pneumoniae (76/176, 43.1%), Acinetobacter baumannii complex (67/176, 38%), and Escherichia coli (29/176,16.4%) were the predominant isolates. Overall, NDM production was the commonest (61/176, 34.6%), followed by the co-production of NDM + OXA-48 and the absence of any CR gene (44/176, 25%), followed by OXA-48 (27/176, 15.3%). In CR K. pneumoniae , the co-production of NDM + OXA-48 was most frequent (34/76, 44.7%), whereas in the A. baumannii complex , no CR gene was detected in the majority of isolates (38/67, 56.7%). bla NDM was the commonest gene in E. coli (18/29, 62%) and A. baumannii complex (26/67, 38.8%).

Conclusion  Xpert Carba-R can identify the molecular mechanism of CR within hours after a blood culture turns positive and, thus, has the potential for optimization of antimicrobial therapy, choosing appropriate novel β-lactam combination agents, as well as infection control interventions.

Therapeutic Options for the Treatment of Carbapenem-resistant Enterobacteriaceae Infections: Hope in the Times of Hype and Despair

How to cite this article: Ansari AS. Therapeutic Options for the Treatment of Carbapenem-resistant Enterobacteriaceae Infections: Hope in the Times of Hype and Despair. Indian J Crit Care Med 2021;25(7):752-753.

Treatment outcome and adverse effects of colistin in adult patients with carbapenem-resistant gram-negative bacteremia from Pakistan

BACKGROUND

Polymyxins (colistin) have emerged for the treatment of carbapenem resistant (CR) gram-negative infections. There is a paucity of data on treatment outcomes and adverse effects of high-dose colistin treatment in Pakistan. The aim of this study was to determine the efficacy and toxicity of colistin in CR bacteremia, including patients with renal failure and on hemodialysis, and to determine patient outcomes.

METHODS

This prospective cohort study was performed from May to December 2017 at Sindh Institute of Urology and Transplantation, Karachi, Pakistan. Patients aged >18 years with documented gram-negative bacteremia were included. Data were compared between those who received colistin and those who did not, including risk factors for CR bacteremia, bacterial clearance, adverse effects, and all-cause mortality up to 14 days of follow-up.

RESULTS

The study included 137 patients, 73 (53.3%) in the colistin group and 64 (46.7%) in the non-colistin group. Patients in the colistin group were 1.47 times more likely to have died by day 14 of follow-up as compared to those in the non-colistin group (19.2% vs 7.8%; relative risk 1.47, p= 0.05). Patients in both groups achieved more than 80% bacteriological clearance. The colistin group patients were less likely to have received appropriate empirical antibiotics as compared to the non-colistin group patients (4.1% vs 62.5%; relative risk 0.09, p< 0.001). Factors significantly associated with mortality were inappropriate empirical antibiotics and acute renal failure. Of the 73 patients in the colistin group, 27 (37.0%) developed reversible neurological adverse effects. Patients with renal insufficiency, not on hemodialysis, were evaluated for colistin nephrotoxicity. Creatinine decreased from 8.08 mg/dl at baseline to 4.85 mg/dl on day 7 in the colistin group, and from 6.5 mg/dl to 3.9 mg/dl in the non-colistin group. Patients with normal renal function had no significant rise in serum creatinine.

CONCLUSIONS

Colistin is efficacious in clearing bacteremia even in patients with impaired renal function. The adverse effects were found to be minimal and reversible. We recommend the use of colistin in combination with carbapenems for CR gram-negative bacteria in renal failure. Most importantly, however, this study highlights the role of empirical colistin treatment in patients with risk factors for CR bacteremia.

Polymyxin Monotherapy vs. Combination Therapy for the Treatment of Multidrug-resistant Infections: A Systematic Review and Meta-analysis

Objectives

The objective of this review was to compare the effectiveness of Colistin monotherapy and combination therapy for the treatment of multidrug-resistant gram-negative bacterial infections.

Data sources

PubMed, Cochrane Library.

Study eligibility interventions and exclusions

In this systematic review, we included all retrospective and prospective studies and randomized controlled trials (RCTs) that compared intravenous polymyxin monotherapy and combination therapy with any other antibiotic for treating multidrug-resistant infections. Studies using inhaled polymyxins with 5 or less than 5 patients were excluded. The primary outcome was 30-day all-cause mortality and if not reported at day 30 we extracted and documented the closest time point. Both crude outcome rates and adjusted effect estimates were extracted for mortality.

Study appraisal data extraction and synthesis

Search string used was "(Colistin OR polymyxin) AND (Enterobacteriaceae OR Klebsiella OR Acinetobacter OR Escherichia coli OR Pseudomonas) AND (random OR prospective OR retrospective OR cohort OR observational OR blind)." Thirty-nine studies were included in our analysis; out of which 6 RCTs were included and 9 studies used carbapenem as the adjunctive antibiotic. Each study was screened and reviewed for eligibility independently by two authors and data extrapolated on an Excel sheet.

Results

The meta-analysis of polymyxin monotherapy vs. combination therapy in multidrug-resistant infections yielded an odds ratio (OR) of 0.81 (95% confidence interval [CI]: 0.65-1.01) with minimal heterogeneity (I ² = 40%), whereas pooled analysis of this comparison in studies that included carbapenem as combination therapy yielded an OR of 0.64 (CI: 0.40-1.03; I ² = 62%). Likewise, the pooled analysis of the RCTs yielded an OR of 0.82 (95% CI: 0.58-1.16, I ² = 22%). All these showed no statistical significance. However, it was seen that polymyxin combination therapy was more effective in multidrug-resistant infections compared to polymyxin monotherapy. The effectiveness was more glaring when carbapenems were used as the combination drug instead of any other antibiotic and more so in many in vitro studies that used polymyxin combination therapy.

Conclusion

Although statistically insignificant, it would be prudent to use polymyxin combination therapy to treat multidrug-resistant gram-negative bacilli (GNB) infection over monotherapy with preference to use carbapenem as the adjunct alongside polymyxins.

How to cite this article

Samal S, Mishra SB, Patra SK, Rath A, Dash A, Nayak B, et al. Polymyxin Monotherapy vs. Combination Therapy for the Treatment of Multidrug-resistant Infections: A Systematic Review and Meta-analysis. Indian J Crit Care Med 2021;25(2):199-206.

A Study of Multidrug-Resistant, Colistin-Only-Sensitive Infections in Intubated and Mechanically Ventilated Patients Over 2 Years

Background and Aims

Multidrug-resistant, Gram-negative infections are increasingly common in the intensive care unit (ICU). This study compares the occurrence and outcome of colistin-only-sensitive (COS) infections among mechanically ventilated patients at a tertiary hospital ICU.

Methods

The study included adult patients admitted over a period of 2 years, who were intubated and mechanically ventilated for more than 48 h. They were divided into two groups, those with COS infections and those without, and their GCS and Acute Physiology and Chronic Health Evaluation II (APACHE II) scores, ICU length of stay, leukocyte count, and mortality were compared. COS patients were divided into neurosurgery, neurology, respiratory, and sepsis with bacteremia groups. The COS organisms in each group, their sources, ICU length of stay, ventilator-free days, and mortality were analyzed.

Results

Three hundred and one patients were selected, of whom 41 (13.6%) had COS infections. COS patients had a longer ICU length of stay than non-COS patients (P = 0.001) but comparable APACHE II and GCS scores, leukocyte count, and mortality. The sepsis group accounted for 8 out of 15 (53%) deaths among COS patients (P = 0.03). Acinetobacter baumannii accounted for 61% of the COS infections, Klebsiella pneumonia: 24.4%, Pseudomonas aeruginosa: 12.2%, and Escherichia coli: 2.4%. Endotracheal secretion cultures accounted for 65.8% of COS isolates, urine cultures 17%, pus cultures 7.3%, and blood cultures 4.9%. ICU length of stay, ventilator-free days, and mortality were similar between each COS organism.

Conclusion

Intubated patients with multidrug-resistant, COS infections have a longer stay in ICU than non-COS patients. COS infections associated with bacteremia have high mortality.

Comparative Study of CDST & Multiplex PCR to Detect MBL Producing Gram-Negative Bacilli among VAP Patients Admitted in a Public Medical College Hospital of Bangladesh

Background: Ventilator-associated pneumonia (VAP) is the most common nosocomial infection in intensive care units (ICU), which accounts for 25% of all ICU infection. Documenting carbapenem-resistant gram-negative bacilli is very important as these strains may often cause outbreaks in the ICU setting and are responsible for the increased mortality and morbidity or limiting therapeutic options. The classical phenotypic method cannot provide an efficient means of diagnosis of the metallo-β-lactamases (MBLs) producer. Polymerase chain reaction (PCR) assays have lessened the importance of the phenotypic approach by detecting metallo-β-lactamase resistance genes such as New Delhi metallo-β-lactamase (NDM), Imipenemase (IMP), Verona integron-encoded metallo-β-lactamase (VIM), Sao Paulo metallo-β-lactamase (SPM), Germany Imipenemase (GIM). Objective: To compare the results of the Combined Disc Synergy Test (CDST) with that of the multiplex PCR to detect MBL-producing gram-negative bacilli. Materials and Method: A total of 105 endotracheal aspirates (ETA) samples were collected from the ICU of a public school in Bangladesh. This cross-sectional study was carried out in the Department of Microbiology, Chittagong for quantitative culture, CDST test, and multiplex PCR for bla_IMP, bla_VIM, bla_NDM genes of MBL producers. Results: Among the 105 clinically suspected VAP cases, the quantitative culture was positive in 95 (90%) and among 95 g-negative bacilli isolated from VAP patients, 46 (48.42%) were imipenem resistant, 30 (65.22%) were MBL producers by CDST, 21 (45.65%) were identified as MBL producers by multiplex PCR. Conclusion: PCR was highly sensitive and specific for the detection of MBL producers.

Indian consensus on the management of CRE infection in critically ill patients (ICONIC) - India

Background: The increasing burden of carbapenem-resistant Enterobacteriaceae (CRE) carriage and infection in different patient settings in India has created an acute need for guidance for clinicians regarding optimal strategies for the management of CRE infection in critically ill patients. Research design and methods: A multidisciplinary panel of 11 Indian experts in CRE infection assembled for comprehensive discussion and consensus development. The experts developed clinical statements through a systematic review of key literature. Main outcome measures: The panel voted anonymously on 60 clinically relevant questions, through a modified Delphi process. Results: Forty-six key clinical consensus statements (CCS) were proposed. The panel reached a consensus on several important issues, providing recommendations on surveillance, diagnosis, prevention, pharmacokinetic challenges, combination therapy, and cornerstone molecules in CRE infections. The panel also proposed a treatment algorithm for NDM-prevalent settings. Conclusion: These consensus statements may offer clinicians expert guidance on the management of CRE infections. There is a dearth of high-/moderate-level evidence on managing CRE infections; the recommendations presented herein are based on expert opinion.

Molecular typing of a large nosocomial outbreak of KPC-producing bacteria in the biggest tertiary-care hospital of Quito, Ecuador

OBJECTIVES

Klebsiella pneumoniae is an opportunistic pathogen associated with nosocomial infections worldwide. Isolates with a K. pneumoniae carbapenemase (KPC)-producing phenotype show reduced susceptibility to first-choice antibiotics. Between 2012-2013, the largest public tertiary-care hospital in Quito (Ecuador) reported an outbreak of KPC-producing bacteria with more than 800 cases. We developed a molecular epidemiological approach to analyse the clonality of K. pneumoniae isolates recovered from selected hospital services and patient samples.

METHODS

A retrospective cohort study was performed based on microbial isolates and their corresponding records from the hospital and referred to Instituto Nacional de Investigación en Salud Pública (INSPI). From 800 isolates that were collected between 2012-2013, a total of 100 isolates were randomly selected for this study. Antimicrobial susceptibility testing was performed according to Clinical and Laboratory Standards Institute (CLSI) guidelines. Genotypic detection and phylogenetic relationship analysis were performed by multilocus sequence typing (MLST). The bla_KPC carbapenemase gene was also amplified by PCR and was sequenced using Sanger sequencing.

RESULTS

Molecular analysis showed that the outbreak had a polyclonal origin with two predominant genotypes, comprising sequence types ST25 and ST258, present in 38 and 36 cases, respectively. These genotypes were found in all studied hospital services including general surgery, intensive care unit and emergency. Thebla_KPC-5 gene was the most prevalent bla_KPC variant in this study.

CONCLUSION

These data indicate that KPC-producing polyclonal K. pneumoniae are frequent causes of nosocomial hospital outbreaks in South America. Similar genotypes have been reported in Colombia, Argentina, Brazil, North America and Asia.

Intravenous colistin combination antimicrobial treatment vs. monotherapy: a systematic review and meta-analysis

BACKGROUND

To evaluate whether intravenous colistin in combination with other antibiotics (IVCC) is associated with lower mortality compared with intravenous colistin monotherapy (IVCM), and to identify factors influencing study outcomes.

METHODS

PubMed and Scopus were searched up to November 2016. Studies were included if they evaluated adult patients with multi-drug-resistant (MDR) or extensively-drug-resistant Gram-negative infections, and reported comparative mortality data (adjusted and unadjusted) for patients receiving IVCC vs. IVCM. Random effects meta-analyses were performed.

FINDINGS

Thirty-two studies (29 observational, three randomized) were included. The overall quality of data was low to very low, and studies were characterized by the lack of adjusted data. The majority of studies were not designed to evaluate the outcome of the meta-analysis, and focused mainly on infections due to Acinetobacter baumannii and Klebsiella pneumoniae. Colistin was administered at variable doses, with or without a loading dose, and in combination with several antibiotics. Overall, IVCC was not associated with lower mortality than IVCM [32 studies, 2328 patients, risk ratio (RR) 0.91, 95% confidence interval (CI) 0.81-1.02, I2 8%]. A significant difference was observed in favour of IVCC when high-dose (>6 million international units) colistin was used (RR 0.80, 95% CI 0.69-0.93), in studies conducted in Asia (RR 0.82, 95% CI 0.71-0.95), in patients with bacteraemia (RR 0.75, 95% CI 0.57-0.98) and in patients with acinetobacter infections (RR 0.88, 95% CI 0.78-1.00).

INTERPRETATION

Overall, low-quality data suggest that IVCC did not lower mortality in patients with MDR Gram-negative infections. However, there is some evidence for a benefit observed with high intravenous doses of colistin.

Epidemiological Analysis of Extended-Spectrum Beta-Lactamase-Producing Bacterial Infections in Adult Live Donor Liver Transplant Patients

Introduction:

Bacterial infections are a leading cause of morbidity and mortality in patients receiving solid-organ transplants. Extended-spectrum beta-lactamases (ESBL) pathogens are the most important pathogenic bacteria infecting these patients.

Aim:

This study aims to evaluate for the incidence and characteristics of ESBL-positive organism, to look for the clinical outcomes in ESBL-positive infected cases, and to evaluate and draft the antibiotic policy in posttransplant patients during the first 28 days posttransplant.

Materials and Methods:

This is a retrospective data analysis of liver transplant recipients infected with ESBL culture-positive infections. All the culture sites such as blood, urine, and endotracheal tube aspirates were screened for the first ESBL infection they had and noted. This data were collected till day 28 posttransplant. The antibiotic susceptibility pattern and the most common organism were also noted.

Results:

A total of 484 patients was screened and 116 patients had ESBL-positive cultures. Out of these, 54 patients had infections and 62 patients were ESBL colonizers. The primary infection site was abdominal fluid (40.7%), with Klebsiella accounting for most of the ESBL infections. Colistin was the most sensitive antibiotic followed by tigecycline. The overall mortality was 11.4% and 31 out of 54 ESBL-infected patients died.

Conclusions:

Infections with ESBL-producing organism in liver transplant recipients has a high mortality and very limited therapeutic options.

Monotherapy versus Combination Therapy against Nonbacteremic Carbapenem-resistant Gram-negative Infections: A Retrospective Observational Study

Background:

Superiority of colistin–carbapenem combination therapy (CCCT) over colistin monotherapy (CMT) against carbapenem-resistant Gram-negative bacterial (CRGNB) infections is not conclusively proven.

Aim:

The aim of the current study was to analyze the effectiveness of both strategies against CRGNB nonbacteremic infections.

Design:

This was a retrospective observational cohort study.

Subjects and Methods:

Case record analysis of patients who had CRGNB nonbacteremic infections identified over a period of 4 years (January 2012–December 2015) was done by medical record review at a tertiary care center in India.

Statistical Analysis:

P < 0.05 was considered as significant. Multivariate analysis was performed using Cox regression.

Results:

Out of 153 patients (pneumonia 115, urinary tract infection 17, complicated skin and soft-tissue infection 18, intra-abdominal infection 1, and meningitis 2), 92 patients received CCCT and 61 received CMT. Univariate analysis revealed higher Acute Physiology and Chronic Health Evaluation II (APACHE II) score, pneumonia as the diagnosis, and Klebsiella as the causative organism to be the risk factors for higher 28-day mortality (P = 0.036, 0.006, 0.016, respectively). Combination therapy had no significant impact on mortality (odds ratio [OR] = 0.91, 95% confidence interval [CI] = 0.327–2.535, P = 0.857). Multivariate analysis revealed that higher APACHE II score and infection due to Klebsiella were found to be independent risk factors for higher mortality (OR = 3.16 and 4.9, 95% CI = 1.34–7.4 and 2.19–11.2, P = 0.008 and 0.0001, respectively).

Conclusions:

In our retrospective single-center series of CRGNB nonbacteremic infections, CCCT was not superior to CMT. Multicenter large observational studies or prospective randomized clinical trials are the need of the hour.

Emergence of Carbapenem Resistant Non-Fermenting Gram-Negative Bacilli Isolated in an ICU of a Tertiary Care Hospital

INTRODUCTION

The emergence and spread of Multi-Drug Resistant (MDR) Non-Fermenting Gram-Negative Bacilli (NFGNB) in Intensive Care Units (ICU) and their genetic potential to transmit diverse antibiotic resistance regardless of their ability to ferment glucose poses a major threat in hospitals. The complex interplay of clonal spread, persistence, transmission of resistance elements and cell-cell interaction leads to the difficulty in controlling infections caused by these multi drug-resistant strains. Among non-fermenting Gram-negative rods, the most clinically significant species Pseudomonas aeruginosa, Acinetobacter baumannii and Stenotrophomonas maltophilia are increasingly acquiring resistant to carbapenems. Carbapenems once considered as a backbone of treatment of life threatening infections appears to be broken as the resistance to carbapenems is on rise.

AIM

To document the prevalence of carbapenem resistance in non-fermenting Gram-negative bacilli isolated from patients with respiratory tract infections in the ICU of Himalayan Institute of Medical Sciences, Dehradun.

MATERIALS AND METHODS

This is a cross-sectional study conducted in ICU patients between October 2015 to March 2016. A total of 366 lower respiratory tract samples were collected from 356 patients with clinical evidence of lower respiratory tract infections in form of Endotracheal (ET) aspirate, Tracheal Tube (TT) aspirate and Bronchoalveolar Lavage (BAL) specimen. Organism identification and the susceptibility testing was done by using an automated system VITEK 2.

RESULTS

Out of 366 samples received 99 NFGNB were isolated and most common sample was ET aspirate sample 256 (64.5%). Acinetobacter baumannii was the most common NFGNB isolated 63 (63.63%) followed by Pseudomonas aeruginosa 25 (25.25%), Elizabethkingia meningoseptica seven (7.07%) and Strenotrophomonas maltophilia four (4.04%). We observed that 90.5% Acinetobacter baumannii were resistant to imipenem and 95.2% resistant to meropenem, Pseudomonas aeruginosa came out to be 52% resistant to imipenem and 56% resistant to meropenem while Stenotrophomonas maltophilia and Elizabethkingia meningoseptica were 100% resistant to carbapenems as they are intrinsically resistant to carbapenems.

CONCLUSION

The resistance rate of carbapenems for NFGNB infections is very high in our study and variable in different regions. Overall carbapenem resistance is on rise. So, the infection control team and microbiologist needs to work together to determine the risk carried by multi drug resistant non-fermenting gram-negative infections and the resistance surveillance programs are mandatory to control these bacteria in ICU settings.