Hypervirulent Klebsiella pneumoniae-related bacteremia in intensive care unit: A retrospective cohort study

INTRODUCTION

Hypervirulent Klebsiella pneumoniae (hvKP) bloodstream infections (BSI) have rarely been reported in critically ill patients.

METHODS

We conducted a retrospective study of KP-BSI between January 2016 and December 2020 in an adult medical intensive care unit (ICU) of our tertiary care hospital. Hypervirulent phenotype was defined by the detection of both rmpA and iutA.

RESULTS

Seventy patients diagnosed with K. pneumonia BSI were included, of whom 9 (13 %) had hvKP infection. Pneumonia accounted for 56 % of hvKP-BSI and for 28 % of those with cKP. Fifty-six percent of patients with hvKP-BSI were homeless, versus 2 % of those with cKP-BSI (p < 0.001). The 30-day mortality rate reached 44 % for hvKP-BSI and 34 % for cKP-BSI (p = 0.7) and did not appear related to the hypervirulent phenotype in multivariable analysis.

DISCUSSION

We here evidenced a new clinical entity of hvKP-BSI associated with pulmonary infection in homeless patients, which exhibits high mortality.

Antimicrobial resistance pattern of Klebsiella isolated from various clinical samples in Ethiopia: a systematic review and meta-analysis

BACKGROUND

The burden of Klebsiella drug resistance to antimicrobials is a major public health concern worldwide; particularly the problem is severe in developing countries including Ethiopia. Therefore, the aim of this systematic review and meta-analysis is to establish the pooled estimate of Klebsiella drug resistance; and antimicrobial-specific resistance pattern among Klebsiella clinical isoaltes in Ethiopia.

METHODS

Articles were searched from PubMed, Google Scholar, and Science direct and grey literature from 2009 to 2019. Four authors have independently extracted data on the prevalence and antimicrobial resistance pattern of the isolates. Statistical analysis was conducted by using Open meta-analyst (version 3.13) and Comprehensive meta-analysis (version 3.3). The main outcome measures were the overall Klebsiella resistance; and drug-specific resistance patterns. A random-effects model was used to determine the pooled resistance prevalence with 95% confidence interval (CI), and significant heterogeneity was considered at p < 0.1; and I2 > 50% using DerSimonian and Laird method. In addition, subgroup analyses were conducted to improve the outcome.

RESULT

We obtained 174 potentially relevant studies through searching electronic databases, and finally, 35 eligible studies were included for meta-analysis. A total of 13,269 study samples participated, from which 1017 Klebsiella species were isolated. The overall Klebsiella resistance in Ethiopia was found to stand at 53.75% (95% CI: 48.35-58.94%). Based on the subgroup analyses; the highest (64.39%); and lowest (46.16%) values were seen in Southern Nations, Nationalities, and Peoples of Ethiopia; and Tigray regions respectively; and the highest Klebsiella resistance was reported to ampicillin (90.56%), followed by amoxicillin (76.01%) and trimethoprim-sulfamethoxazole (66.91%). A relatively low level of resistance rate was observed to amikacin (16.74%) and cefoxitin (29.73%).

CONCLUSION

The pooled Klebsiella resistance was found to be considerably high (53.75%) to most of the essential antibiotics in Ethiopia. Klebsiella was highly resistant to ampicillin and amoxicillin but relatively lower to amikacin. Therefore, appropriate interventional strategies need to be taken to address the emerging resistance of Klebsiella species.

Klebsiella pneumoniae invasion syndrome: a case of liver abscess combined with lung abscess, endophthalmitis, and brain abscess

Klebsiella pneumoniae invasion syndrome (KPIS) is a critical multi-site infection that is usually caused by highly virulent Klebsiella pneumonia. It is relatively common in Asian patients with diabetes and leads to sepsis, which has a high mortality rate. We report the case of a man in his early 40s who presented to the hospital with blurred vision in his left eye of 7 days’ duration and fever of 1 day’s duration. After a complete examination, he was diagnosed with KPIS on the basis of his liver abscessation, lung abscessation, endophthalmitis of the left eye and brain abscessation. After needle puncture and drainage of the left eye and liver abscess and anti-bacterial treatment with meropenem, the patient recovered well. When KPIS is suspected, attention should be paid to the sites of infection and the selection of the most appropriate antibiotics, but the most important aim should be to drain the lesions in a timely manner to improve the patient’s prognosis.

Emergence of an XDR and carbapenemase-producing hypervirulent Klebsiella pneumoniae strain in Taiwan

Background

Carbapenemase-producing Klebsiella pneumoniae causes high mortality owing to the limited therapeutic options available. Here, we investigated an emergent carbapenem-resistant K. pneumoniae strain with hypervirulence found among KPC-2-producing strains in Taiwan.

Methods

KPC-producing K. pneumoniae strains were collected consecutively from clinical specimens at the Taipei Veterans General Hospital between January 2012 and December 2014. Capsular types and the presence of rmpA/rmpA2 were analysed, and PFGE and MLST performed using these strains. The strain positive for rmpA/rmpA2 was tested in an in vivo mouse lethality study to verify its virulence and subjected to WGS to delineate its genomic features.

Results

A total of 62 KPC-2-producing K. pneumoniae strains were identified; all of these belonged to ST11 and capsular genotype K47. One strain isolated from a fatal case with intra-abdominal abscess (TVGHCRE225) harboured rmpA and rmpA2 genes. This strain was resistant to tigecycline and colistin, in addition to carbapenems, and did not belong to the major cluster in PFGE. TVGHCRE225 exhibited high in vivo virulence in the mouse lethality experiment. WGS showed that TVGHCRE225 acquired a novel hybrid virulence plasmid harbouring a set of virulence genes (iroBCDN, iucABCD, rmpA and rmpA2, and iutA) compared with the classic ST11 KPC-2-producing strain.

Conclusions

We identified an XDR ST11 KPC-2-producing K. pneumoniae strain carrying a hybrid virulent plasmid in Taiwan. Active surveillance focusing on carbapenem-resistant hypervirulent K. pneumoniae strains is necessary, as the threat to human health is imminent.

High mortality among patients infected with hypervirulent antimicrobial-resistant capsular type K1 Klebsiella pneumoniae strains in Taiwan

Capsular type K1 Klebsiella pneumoniae, highly virulent strains which are common in Asian countries, can cause pyogenic infections. These hypervirulent strains are usually susceptible to most antimicrobials, except for ampicillin. Little is known regarding the clinical and molecular characteristics of antimicrobial-resistant K1 K. pneumoniae strains. This retrospective study evaluated patients infected with capsular type K1 K. pneumoniae strains in a Taiwanese medical centre between April 2013 and March 2016. Antimicrobial-resistant strains were defined based on non-susceptibility to antimicrobial agents except ampicillin. We compared the clinical outcome of patients infected with and without antimicrobial-resistant strains. The in vivo virulence, genetic relatedness, and resistance mechanisms of these hypervirulent antimicrobial-resistant strains were also investigated. A total of 182 capsular type K1 K. pneumoniae strains were identified, including 18 antimicrobial-resistant strains. The 28-day mortality rate among the 18 cases caused by antimicrobial-resistant strains was significantly higher than that among 164 cases caused by antimicrobial-sensitive strains (50% vs. 10.4%, P < 0.001). Infection with antimicrobial-resistant strain independently increased the 28-day mortality risk. Most antimicrobial-resistant strains were not clonally related, and they exhibited high in vivo virulence in a mouse lethality experiment. The major resistance mechanisms involved the presence of β-lactamases and the overexpression of efflux pumps. In conclusion, hypervirulent antimicrobial-resistant capsular type K1 K. pneumoniae strains can predispose to a fatal outcome. These strains may represent an emerging threat to public health in Taiwan.

Risk factors and clinical outcomes of hypervirulent Klebsiella pneumoniae induced bloodstream infections

The prevalence of hypervirulent Klebsiella pneumoniae (hvKP) is high in China, but clinical characteristics and outcomes of hvKP induced bloodstream infections (BSIs) are not clear. The purpose of the present study was to determine the risk factors and clinical outcomes of hvKP-BSIs in populations admitted in a teaching hospital of Nanjing, China. The genetic characteristics and antibiotic resistance patterns of the hvKP strains were further analyzed. A retrospective study was conducted in 143 patients with K. pneumoniae BSIs at Jinling Hospital in China from September 2015 to December 2016. A positive polymerase chain reaction (PCR) amplification of the plasmid-borne rmpA (p-rmpA) and aerobactin (iucA) was identified as hvKP. Overall, 24.5% (35/143) of K. pneumoniae isolates were hvKP. Multivariate analysis implicated diabetes mellitus (OR = 3.356) and community-acquired BSIs (OR = 4.898) as independent risk factors for hvKP-BSIs. The 30-day mortality rate of the hvKP-BSIs group was 37.1% (13/35) compared with 40.7% (44/108) in the cKP-BSIs control group (P = 0.706). The KPC-producing isolates (OR = 2.851), underlying disease with gastrointestinal fistula (OR = 3.054), APACHE II score ≥ 15 (OR = 6.694) and Pitt bacteremia score ≥ 2 (OR = 6.232) at infection onset were independent predictors for 30-day mortality of K. pneumoniae bacteremia patients. A high percentage (57.1%, 20/35) of KPC-producing isolates was observed among hvKP strains and ST11 was dominant in hvKP strains (17/35, 48.6%). KPC-producing hvKP is emerging, indicating the importance of epidemiologic surveillance and clinical awareness of this pathogen.

Biliary diseases as main causes of pyogenic liver abscess caused by extended-spectrum beta-lactamase-producing Enterobacteriaceae

BACKGROUND & AIMS

Little is known about aetiology and morbidity and clinical characteristics of pyogenic liver abscess caused by extended-spectrum beta-lactamase-producing Enterobacteriaceae.

METHODS

An analysis between pyogenic liver abscess patients caused by extended-spectrum beta-lactamase-producing Enterobacteriaceae isolates and those caused by non-extended-spectrum beta-lactamase-producing Enterobacteriaceae was performed.

RESULTS

Among 817 pyogenic liver abscess patients, there were 176 patients (21.5%) with pyogenic liver abscess of biliary origin, and 67 pyogenic liver abscess patients (8.2%) caused by extended-spectrum beta-lactamase-producing Enterobacteriaceae isolates (mainly Escherichia coli and Klebsiella pneumoniae). Of 176 pyogenic liver abscess patients related to biliary disorders, there were 48 pyogenic liver abscess patients (27.3%) caused by extended-spectrum beta-lactamase-producing Enterobacteriaceae. Within 67 pyogenic liver abscess patients caused by Enterobacteriaceae expressing extended-spectrum beta-lactamases, the occurrences of 48 pyogenic liver abscess patients (71.6%) were associated with biliary disorders. When compared with pyogenic liver abscess patients caused by non-extended-spectrum beta-lactamase-producing Enterobacteriaceae, there were significantly greater incidences of polymicrobial infections, bacteremia, pulmonary infection, recurrence and death in pyogenic liver abscess patients caused by extended-spectrum beta-lactamase-producing Enterobacteriaceae. Carbapenems remain mainstay drugs against extended-spectrum beta-lactamase-producing E. coli and K. pneumoniae. Independent risk factors for occurrence of pyogenic liver abscess caused by extended-spectrum beta-lactamase-producing Enterobacteriaceae were biliary disorders including extra- and intrahepatic cholangiolithiasis and an abnormal bilioenteric communication between bile and gut, a treatment history of malignancy such as operation and chemotherapy, pulmonary infection, and diabetes mellitus.

CONCLUSIONS

Pyogenic liver abscess caused by extended-spectrum beta-lactamase-producing Enterobacteriaceae isolates mainly occurs in patients with biliary disorders or with a treatment history of malignancy. The mainstay of treatment remains carbapenems in combination with adequate aspiration or drainage.

Rapid Detection of K1 Hypervirulent Klebsiella pneumoniae by MALDI-TOF MS

Hypervirulent strains of Klebsiella pneumoniae (hvKP) are genetic variants of K. pneumoniae which can cause life-threatening community-acquired infection in healthy individuals. Currently, methods for efficient differentiation between classic K. pneumoniae (cKP) and hvKP strains are not available, often causing delay in diagnosis and treatment of hvKP infections. To address this issue, we devised a Matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry (MS) approach for rapid identification of K1 hvKP strains. Four standard algorithms, genetic algorithm (GA), support vector machine (SVM), supervised neural network (SNN), and quick classifier (QC), were tested for their power to differentiate between K1 and non-K1 strains, among which SVM was the most reliable algorithm. Analysis of the receiver operating characteristic curves of the interest peaks generated by the SVM model was found to confer highly accurate detection sensitivity and specificity, consistently producing distinguishable profiles for K1 hvKP and non-K1 strains. Of the 43 K. pneumoniae modeling strains tested by this approach, all were correctly identified as K1 hvKP and non-K1 capsule type. Of the 20 non-K1 and 17 K1 hvKP validation isolates, the accuracy of K1 hvKP and non-K1 identification was 94.1 and 90.0%, respectively, according to the SVM model. In summary, the MALDI-TOF MS approach can be applied alongside the conventional genotyping techniques to provide rapid and accurate diagnosis, and hence prompt treatment of infections caused by hvKP.