COVID-19 and Fatal Sepsis Caused by Hypervirulent Klebsiella pneumoniae, Japan, 2020

Screening of Klebsiella pneumoniae subsp. pneumoniae Strains with Multi-Drug Resistance and Virulence Profiles Isolated from an Italian Hospital between 2020 and 2023

Klebsiella pneumoniae strains that are resistant to multiple drugs (KPMDRs), which are often acquired in hospital settings and lead to healthcare-associated infections, pose a serious public health threat, as does hypervirulent K. pneumoniae (hvKp), which can also cause serious infections in otherwise healthy individuals. The widespread and often unnecessary use of antibiotics seen during the recent COVID-19 pandemic has exacerbated the challenges posed by antibiotic resistance in clinical settings. There is growing concern that hypervirulent (hvKp) strains may acquire genes that confer antimicrobial resistance, thus combining an MDR profile with their increased ability to spread to multiple body sites, causing difficult-to-treat infections. This study aimed to compare resistance and virulence profiles in KPC-3-producing K. pneumoniae isolates collected over four years (2020-2023). A genome-based surveillance of all MDR CRE-K. pneumoniae was used to identify genetic differences and to characterize the virulence and resistance profiles. Our results provide a picture of the evolution of resistance and virulence genes and contribute to avoiding the possible spread of isolates with characteristics of multi-drug resistance and increased virulence, which are thought to be one of the main global challenges to public health, within our hospital.

A Sequent of Gram-Negative Co-Infectome-Induced Acute Respiratory Distress Syndrome Are Potentially Subtle Aggravators Associated to the SARS-CoV-2 Evolution of Virulence

Acute respiratory distress syndrome (ARDS) is one of the major problems in COVID-19 that is not well understood. ARDS is usually complicated by co-infections in hospitals. Although ARDS is inherited by Europeans and Africans, this is not clear for those from the Middle East. There are severe limitations in correlations made between COVID-19, ARDS, co-infectome, and patient demographics. We investigated 298 patients for associations of ARDS, coinfections, and patient demographics on COVID-19 patients' outcomes. Of the 149 patients examined for ARDS during COVID-19, 16 had an incidence with a higher case fatality rate (CFR) of 75.0% compared to those without ARDS (27.0%) (p value = 0.0001). The co-infectome association showed a CFR of 31.3% in co-infected patients; meanwhile, only 4.8% of those without co-infections (p value = 0.01) died. The major bacteria were Acinetobacter baumannii and Escherichia coli, either alone or in a mixed infection with Klebsiella pneumoniae. Kaplan-Meier survival analysis of COVID-19 patients with and without ARDS revealed a significant difference in the survival time of patients with ARDS (58.8 +/- 2.7 days) and without ARDS (41.9 +/- 1.8 days) (p value = 0.0002). These findings prove that increased hospital time was risky for co-infectome-induced SDRS later on. This also explained that while empiric therapy and lethal ventilations delayed the mortality in 75% of patients, they potentially did not help those without co-infection or ARDS who stayed for shorter times. In addition, the age of patients (n = 298) was significantly associated with ARDS (72.9 +/- 8.9) compared to those without it (56.2 +/- 15.1) and was irrespective of gender. However, there were no significant differences neither in the age of admitted patients before COVID-19 (58.5 +/- 15.3) and during COVID-19 (57.2 +/- 15.5) nor in the gender and COVID-19 fatality (p value 0.546). Thus, Gram-negative co-infectome potentially induced fatal ARDS, aggravating the COVID-19 outcome. These findings are important for the specific differential diagnosis of patients with and without ARDS and co-infections. Future vertical investigations on mechanisms of Gram-negative-induced ARDS are imperative since hypervirulent strains are rapidly circulating. This study was limited as it was a single-center study confined to Ha'il hospitals; a large-scale investigation in major national hospitals would gain more insights.

High Prevalence of Respiratory Co-Infections and Risk Factors in COVID-19 Patients at Hospital Admission During an Epidemic Peak in China

Background

Recent research highlights the contribution of co-infections to elevated disease severity and mortality among COVID-19 patients. Given China's decision to ease epidemic prevention policies in December 2022, a comprehensive exploration of the risks and characteristics of co-infections with respiratory pathogens becomes imperative.

Methods

We conducted a retrospective analysis of 716 COVID-19 patients admitted to a primary hospital in China. The detection of twelve respiratory pathogens was conducted using qPCR, and the potential risk factors were analyzed through Cox regression analysis.

Results

Within this cohort, 76.82% of cases exhibited co-infection involving eleven distinct pathogens. Among these, bacterial co-infections were observed in 74% of cases, with Streptococcus pneumoniae and Haemophilus influenzae emerging as the most prevalent bacterial co-infection agents. Additionally, 15% of cases presented with viral co-infections, predominantly involving influenza A virus and respiratory syncytial virus. Nevertheless, our investigation suggested that there might be some inappropriate antibiotic use in treatments. Furthermore, risk analysis unveiled dyspnea, hypoproteinemia, low lymphocyte counts, and co-infection with Mycoplasma pneumoniae as prominent risk factors for COVID-19 inpatients.

Conclusion

Our findings underscore a significant occurrence of co-infections among COVID-19 patients during the epidemic, emphasizing the need for enhanced antibiotic stewardship. Effective management strategies should encompass respiratory status, nutritional aspects, and vigilance towards co-infections involving M. pneumoniae during COVID-19 treatment. This study underscores the significance of comprehensive management protocols to address the multifaceted challenges presented by co-infections in COVID-19 patients.

Antibiotic-Resistant ESKAPE Pathogens and COVID-19: The Pandemic beyond the Pandemic

Antibacterial resistance is a renewed public health plague in modern times, and the COVID-19 pandemic has rekindled this problem. Changes in antibiotic prescribing behavior, misinformation, financial hardship, environmental impact, and governance gaps have generally enhanced the misuse and improper access to antibiotics during the COVID-19 pandemic. These determinants, intersected with antibacterial resistance in the current pandemic, may amplify the potential for a future antibacterial resistance pandemic. The occurrence of infections with multidrug-resistant (MDR), extensively drug-resistant (XDR), difficult-to-treat drug-resistant (DTR), carbapenem-resistant (CR), and pan-drug-resistant (PDR) bacteria is still increasing. The aim of this review is to highlight the state of the art of antibacterial resistance worldwide, focusing on the most important pathogens, namely Enterobacterales, Acinetobacter baumannii, and Klebsiella pneumoniae, and their resistance to the most common antibiotics.

Klebsiella pneumoniae C o-infection Leads to Fatal Pneumonia in SARS-CoV-2-infected Mice

SARS-CoV-2 patients have been reported to have high rates of secondary Klebsiella pneumoniae infections. Klebsiella pneumoniae is a commensal that is typically found in the respiratory and gastrointestinal tracts. However, it can cause severe disease when a person's immune system is compromised. Despite a high number of K. pneumoniae cases reported in SARS-CoV-2 patients, a co-infection animal model evaluating the pathogenesis is not available. We describe a mouse model to study disease pathogenesis of SARS-CoV-2 and K. pneumoniae co-infection. BALB/cJ mice were inoculated with mouse-adapted SARS-CoV-2 followed by a challenge with K. pneumoniae . Mice were monitored for body weight change, clinical signs, and survival during infection. The bacterial load, viral titers, immune cell accumulation and phenotype, and histopathology were evaluated in the lungs. The co-infected mice showed severe clinical disease and a higher mortality rate within 48 h of K. pneumoniae infection. The co-infected mice had significantly elevated bacterial load in the lungs, however, viral loads were similar between co-infected and single-infected mice. Histopathology of co-infected mice showed severe bronchointerstitial pneumonia with copious intralesional bacteria. Flow cytometry analysis showed significantly higher numbers of neutrophils and macrophages in the lungs. Collectively, our results demonstrated that co-infection of SARS-CoV-2 with K. pneumoniae causes severe disease with increased mortality in mice.

Characterization of aminoglycoside resistance genes in multidrug-resistant Klebsiella pneumoniae collected from tertiary hospitals during the COVID-19 pandemic

Since the peak of the coronavirus disease 2019 (COVID-19) pandemic, concerns around multidrug-resistant (MDR) bacterial pathogens have increased. This study aimed to characterize aminoglycoside resistance genes in MDR Klebsiella pneumoniae (K. pneumoniae) collected during the COVID-19 pandemic. A total of 220 clinical isolates of gram-negative bacteria were collected from tertiary hospitals in Makkah, Saudi Arabia, between April 2020 and January 2021. The prevalence of K. pneumoniae was 40.5%; of the 89 K. pneumoniae isolates, MDR patterns were found among 51 (57.3%) strains. The MDR isolates showed elevated resistance rates to aminoglycoside agents, including amikacin (100%), gentamicin (98%), and tobramycin (98%). PCR assays detected one or more aminoglycoside genes in 42 (82.3%) MDR K. pneumoniae strains. The rmtD gene was the most predominant gene (66.7%; 34/51), followed by aac(6')-Ib and aph(3')-Ia (45.1%; 23/51). The aac(3)-II gene was the least frequent gene (7.8%; 4/51) produced by our isolates. The rmtC gene was not detected in the studied isolates. Our findings indicated a high risk of MDR bacterial infections through the COVID-19 outbreak. Therefore, there is a need for continuous implementation of effective infection prevention control (IPC) measures to monitor the occurrence of MDR pathogens and the emergence of MDR bacterial infections through the COVID-19 outbreak.

Epidemiological characteristics of SHV, cmlv, and FosA6-producing carbapenem-resistant Klebsiella pneumoniae based on whole genome sequences in Jiangsu, China

Carbapenem-resistant Klebsiella pneumoniae (CRKP), particularly those with high virulence, cause invasive disease in clinical settings. An epidemiological investigation was conducted on the evolution, virulence, and antimicrobial resistance of CRKP isolates in two tertiary teaching hospitals in Jiangsu, China from November 2020 to December 2021. There were 31 different CRKP strains discovered. We performed whole genome sequencing (WGS) on 13 SHV, cmlv, and FosA6-producing CRKP to reveal molecular characteristics. Five ST15/ST11 isolates had CRISPR-Cas systems. By conjugation tests, KPC-2 can be transmitted horizontally to E. coil. A conjugative pHN7A8-related multi-resistance plasmid (KPC-2, blaCTX-M-65, blaTEM-1, fosA3, catII, and rmtB) was first discovered in CRKP clinical isolates. Using bacteriological testing, a serum killing assay, and an infection model with Galleria mellonella, three ST11-K64 KPC-2 generating carbapenem-resistant hypervirulent Klebsiella pneumoniae (CR-hvKP) were identified. These strains harbored a virulent plasmid and an IncFII-family pKPC/pHN7A8 conjugative plasmid, which led to hypervirulence and resistance. One of these CR-hvKPs, which co-harbored KPC-2, NDM-6, SHV-182, SHV-64, and blaCTX-M-122 genes, was first discovered. Importantly, this CR-hvKP strain also produced biofilm and had non-inferior fitness. The widespread use of ceftazidime/avibactam might provide this CR-hvKP with a selective advantage; hence, immediate action is required to stop its dissemination. Another important finding is the novel ST6136 in K. pneumoniae. Finally, the sterilization efficiency rates of Fe2C nanoparticles in CRKP were more than 98%. Furthermore, our novel antibacterial Fe2C nanoparticles may also provide a therapeutic strategy for infections.

A case report of fatal COVID-19 complicated by rapidly progressive sepsis caused by Klebsiella variicola

BACKGROUND

There is a growing interest in Klebsiella variicola as a causative pathogen in humans, though its clinical features and the impact of co-infection or secondary infection with COVID-19 remain unknown.

CASE PRESENTATION

A 71-year-old man presented with fever, altered mental status and generalized weakness and was admitted to ICU due to severe COVID-19 pneumonia. He was newly diagnosed with type II diabetes mellitus upon admission. On hospital day 3, his respiratory status deteriorated, requiring invasive mechanical ventilation. On hospital day 10, superimposed bacterial pneumonia was suspected and subsequently, broad-spectrum antibiotics were administered for the associated bloodstream infection. On hospital day 13, despite administration of active antibiotics and appropriate source control, he decompensated and died. The causative organism isolated from blood cultures was initially reported as K. pneumoniae, but it was identified as K. variicola by a genetic analysis. A representative isolate (FUJ01370) had a novel multilocus sequence typing allelic profile (gapA-infB-mdh-pgi-phoE-rpoB-tonB: 16-24-21-27-52-17-152), to which sequence type 5794 was assigned (GenBank assembly accession: GCA_019042755.1).

CONCLUSIONS

We report a fatal case of respiratory and bloodstream infection due to K. variicola complicating severe COVID-19. Co-infection or secondary infection of K. variicola in COVID-19 is likely under-recognized and can be fulminant as in this case.

Assessing and Reassessing the Association of Comorbidities and Coinfections in COVID-19 Patients

Coronavirus disease 2019 (COVID-19) has posed an enormous global health and economic burden. To date, 324 million confirmed cases and over 5.5 million deaths have been reported. Several studies have reported comorbidities and coinfections associated with complicated and serious COVID-19 infections. Data from retrospective, prospective, case series, and case reports from various geographical locations were assessed, which included ~ 2300 COVID-19 patients with varying comorbidities and coinfection. We report that Enterobacterales with Staphylococcus aureus was the most while Mycoplasma pneumoniae was the least prevalent coinfection in COVID-19 patients with a comorbidity. In this order, hypertension, diabetes, cardiovascular disease, and pulmonary disease were the prevalent comorbidities observed in COVID-19 patients. There was a statistically significant difference in the prevalent comorbidities observed in patients coinfected with Staphylococcus aureus and COVID-19 and a statistically non-significant difference in the prevalent comorbidities in patients coinfected with Mycoplasma pneumoniae and COVID-19 as compared to similar infections in non-COVID-19 coinfection. We report a significant difference in the prevalent comorbidities recorded in COVID-19 patients with varying coinfections and varying geographic study regions. Our study provides informative data on the prevalence of comorbidities and coinfections in COVID-19 patients to aid in evidence-based patient management and care.

Characterization of a Lytic Bacteriophage and Demonstration of Its Combined Lytic Effect with a K2 Depolymerase on the Hypervirulent Klebsiella pneumoniae Strain 52145

Klebsiella pneumoniae is a nosocomial pathogen. Among its virulence factors is the capsule with a prominent role in defense and biofilm formation. Bacteriophages (phages) can evoke the lysis of bacterial cells. Due to the mode of action of their polysaccharide depolymerase enzymes, phages are typically specific for one bacterial strain and its capsule type. In this study, we characterized a bacteriophage against the capsule-defective mutant of the nosocomial K. pneumoniae 52145 strain, which lacks K2 capsule. The phage showed a relatively narrow host range but evoked lysis on a few strains with capsular serotypes K33, K21, and K24. Phylogenetic analysis showed that the newly isolated Klebsiella phage 731 belongs to the Webervirus genus in the Drexlerviridae family; it has a 31.084 MDa double-stranded, linear DNA with a length of 50,306 base pairs and a G + C content of 50.9%. Out of the 79 open reading frames (ORFs), we performed the identification of orf22, coding for a trimeric tail fiber protein with putative capsule depolymerase activity, along with the mapping of other putative depolymerases of phage 731 and homologous phages. Efficacy of a previously described recombinant K2 depolymerase (B1dep) was tested by co-spotting phage 731 on K. pneumoniae strains, and it was demonstrated that the B1dep-phage 731 combination allows the lysis of the wild type 52145 strain, originally resistant to the phage 731. With phage 731, we showed that B1dep is a promising candidate for use as a possible antimicrobial agent, as it renders the virulent strain defenseless against other phages. Phage 731 alone is also important due to its efficacy on K. pneumoniae strains possessing epidemiologically important serotypes.

SARS-CoV-2 Related Viral Respiratory Co-Infections: A Narrative Review

Background

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) is the new coronavirus originating from Wuhan, China, responsible for the illness known as coronavirus disease 2019 (COVID-19). Early experience and the recent literature have shown that co-infection of SARS-CoV-2 with another respiratory virus might occur. Similar symptoms of acute respiratory infections (ARIs) and COVID-19 represent a challenge for diagnostic and therapeutic efficacy and may modify COVID-19 outcomes.

Materials and Methods

We reviewed the literature on the epidemic pattern and major learning points on important aspects of SARS-CoV-2-related viral respiratory co-infections during the COVID-19 pandemic. Databases such as PubMed, Scopus, Science Direct, and Google Scholar were used to conduct a comprehensive search.

Results

The circulation of respiratory viruses changed as the COVID-19 epidemic continues. Phenomena like viral interference, resource competition, and differences in virus-host range might explain why simultaneous viral respiratory infections have seemed to vanish with the spread of SARS-CoV-2.

Conclusion

Key research to be conducted during this pandemic should include the simultaneous screening of other respiratory pathogens with many available commercial platforms for transmission containment and appropriate clinical management.

New advances in management and treatment of multidrug-resistant Klebsiella pneumoniae

INTRODUCTION

The management of multidrug-resistant (MDR) Klebsiella pneumoniae (KP) represents a major challenge in the field of infectious diseases. It is associated with a high rate of nosocomial infections with a mortality rate that reaches approximately 50%, even when using an effective antimicrobial therapy. Therefore, combined actions addressing infection control and antibiotic stewardship are required to delay the emergence of resistance. Since new antimicrobial agents targeting MDR-GNB bacteria have been produced during the last years and are now available for physicians to treat MDR, it is fundamental to choose appropriate antimicrobial therapy for K. pneumoniae infection.

AREAS COVERED

The PubMed database was searched to review the most significant recent literature on the topic, including data from articles coming from endemic areas and from the current European and American Guidelines.

EXPERT OPINION

We explore the most effective strategies for prevention of MDR-KP spread and the currently available treatment options, focusing on comparing old strategies and new compounds. We reviewed data concerning newly developed drugs that could play an important role in the future; we also propose a treatment algorithm that could be useful for physicians in daily clinical practice.

Clinical and genomic characterization of hypervirulent Klebsiella pneumoniae (hvKp) infections via passive surveillance in Southern California, 2020–2022

Hypervirulent Klebsiella pneumoniae (hvKp) is more invasive and virulent than classical K. pneumoniae, and requires specialized treatment. To raise clinical awareness, this study determined the prevalence, clinical characteristics, and genomic epidemiology of hvKp infections in Southern California (SoCal) by conducting a passive surveillance in a single large academic medical center. We report here that hvKp infections were more common than expected, accounting for 2.6% of invasive K. pneumoniae infections, and presented with a wide disease spectrum, occasionally mimicking tumors, even co-infecting a COVID-19 patient. Most infections were community acquired with no recent international travel, suggesting hvKp strains are circulating in the community. Genomic analysis revealed genetic diversity, with the K1-ST23 lineage predominating but not clonal, and multiple sequence types of K2 including a SoCal unique K2-ST66 sublineage that had been unrecognized. Our findings highlight the urgency of heightened awareness of hvKp infection in the US, the need for rapid diagnosis of hvKp, and the necessity of implementing robust surveillance programs for hvKp at the institutional or local level.

Successful treatment of acute respiratory distress syndrome caused by hypervirulent Klebsiella pneumoniae with extracorporeal membrane oxygenation and continuous renal replacement therapy: A case report and literature review

Hypervirulent Klebsiella pneumoniae (hvKP) causes invasive infections and leads to high morbidity and mortality rates. Here, we report the case of a Chinese man with diabetes mellitus who developed acute respiratory distress syndrome and septic shock due to hvKP belonging to the K1 strain. The patient was treated with venovenous extracorporeal membrane oxygenation and continuous renal replacement therapy, in combination with antibiotics and recovered well. Clinicians should be aware of fatal infections caused by hvKP and investigate the best treatment options for patients at various stages of infection.

COVID-19 Clinical Profiles and Fatality Rates in Hospitalized Patients Reveal Case Aggravation and Selective Co-Infection by Limited Gram-Negative Bacteria

Bacterial co-infections may aggravate COVID-19 disease, and therefore being cognizant of other pathogens is imperative. We studied the types, frequency, antibiogram, case fatality rates (CFR), and clinical profiles of co-infecting-pathogens in 301 COVID-19 patients. Co-infection was 36% (n = 109), while CFR was 31.2% compared to 9.9% in non-co-infected patients (z-value = 3.1). Four bacterial species dominated, namely, multidrug-resistant Klebsiella pneumoniae (37%, n = 48), extremely drug-resistant Acinetobacter baumannii (26%, n = 34), multidrug-resistant Eschericia. coli (18.6%, n = 24), and extremely drug-resistant Pseudomonas aeruginosa (8.5%, n = 11), in addition to other bacterial species (9.3%, n = 12). Increased co-infection of K. pneumoniae and A. baumannii was associated with increased death rates of 29% (n = 14) and 32% (n = 11), respectively. Klebsiella pneumoniae was equally frequent in respiratory and urinary tract infections (UTI), while E. coli mostly caused UTI (67%), and A. baumannii and P. aeruginosa dominated respiratory infections (38% and 45%, respectively). Co-infections correlated with advance in age: seniors ≥ 50 years (71%), young adults 21–49 years (25.6%), and children 0–20 years (3%). These findings have significant clinical implications in the successful COVID-19 therapies, particularly in geriatric management. Future studies would reveal insights into the potential selective mechanism(s) of Gram-negative bacterial co-infection in COVID-19 patients.

Molecular Epidemiology of Hypervirulent K. pneumoniae and Problems of Health-Care Associated Infections

The review describes virulence factors of hypervirulent K. pneumoniae (hvKp) including genes determining its virulence and discusses their role in the development of health-care associated infections. The contribution of individual virulence factors and their combination to the development of the hypervirulence and the prospects of using these factors as biomarkers and therapeutic targets are described. Virulence factors of hvKp and “classical” K. pneumoniae strains (cKp) with no hypervirulence genes were compared. The mechanisms of biofilm formation by hvKp and high incidence of its antibiotic resistance are of particular importance for in health care institutions. Therefore, the development of methods for hvKp identification allowing early prevention of severe hvKp infection and novel approaches to abrogate its spreading are new challenges for epidemiology, infection diseases, and critical care medicine. New technologies including bacteriological and molecular studies make it possible to develop innovative strategies to diagnose and treat infection caused by hvKp. These include monitoring of both genetic biomarkers of hvKp and resistance plasmid that carry of virulence genes and antibiotic resistance genes, creation of immunological agents for the prevention and therapy of hvKp (vaccines, monoclonal antibodies) as well as personalized hvKp-specific phage therapies and pharmaceuticals enhancing the effect of antibiotics. A variety of approaches can reliably prepare our medicine for a new challenge: spreading of life-threatening health-care associated infections caused by antibiotic-resistant hvKp strains.

Emergence of polymyxin B-heteroresistant hypervirulent Klebsiella pneumoniae from an individual in the community with asymptomatic bacteriuria

Background

The heteroresistance of polymyxin B, a last-resort antibiotic used to treat many serious bacterial infections, may lead to antibiotic treatment failure. However, polymyxin B-heteroresistant isolates are rare in individuals living in the community. We report a polymyxin B-heteroresistant hypervirulent Klebsiella pneumoniae (hvKP) isolate from an individual in the community with asymptomatic bacteriuria.

Results

The NYTJ35 isolate had multiple virulence genes that encoded a mucoid phenotype regulator (rmpA), aerobactin (iucABCD-iutA), salmochelin (iroBCDN), yersiniabactin (irp1–2 and ybtAEPQSTUX), and a truncated rmpA2. Infection of galleria mellonella larvae indicated the isolate was hypervirulent. Antimicrobial susceptibility testing showed it was susceptible to all tested antibiotics except polymyxin B. The proportion of surviving bacteria was 1.2 × 10^− 7 based on the population analysis profile (PAP) method, suggesting the presence of polymyxin B heteroresistance. The isolate was not hypermucoviscous, but it was a strong biofilm producer. It had capsular serotype K1 and belonged to sequence type 23 (ST23). The isolate also had the D150G substitution in phoQ, which is known to confer polymyxin B resistance.

Conclusions

We identified the co-occurrence of hypervirulence and polymyxin B heteroresistance in a K. pneumoniae isolate from an individual with asymptomatic bacteriuria. We suggest the use of increased screening for hvKP in individuals living in the community.

Spread of hypervirulent multidrug-resistant ST147 Klebsiella pneumoniae in patients with severe COVID-19: an observational study from Italy, 2020-21

Objectives

To report an outbreak of hypervirulent Klebsiella pneumoniae (hvKp) in COVID-19 patients.

Methods

Prospective, observational study including consecutive COVID-19 patients with hvKp infections admitted to the University Hospital of Pisa (Italy). Clinical data and outcome of patients were collected. All patients were followed-up to 30 days from the diagnosis of infection. Mortality within 30 days of the diagnosis of hvKp infection was reported. The hypermucoviscous phenotype was determined by the ‘string test’. Molecular typing was performed on three strains collected during different periods of the outbreak. The strains underwent whole genome sequencing using the Illumina MiSeq instrument. The complete circular assemblies were also obtained for the chromosome and a large plasmid using the Unicycler tool.

Results

From November 2020 to March 2021, hvKp has been isolated from 36 COVID-19 patients: 29/36 (80.6%) had infections (15 bloodstream infections, 8 ventilator-associated pneumonias and 6 complicated urinary tract infections), while 7/36 (19.4%) had colonization (3 urine, 2 rectal and 2 skin). The isolates belonged to ST147 and their plasmid carried three replicons of the IncFIB (Mar), IncR and IncHI1B types and several resistance genes, including the rmpADC genes encoding enhancers of capsular synthesis. The hvKp isolates displayed an ESBL phenotype, with resistance to piperacillin/tazobactam and ceftolozane/tazobactam and susceptibility only to meropenem and ceftazidime/avibactam. The majority of patients were treated with meropenem alone or in combination with fosfomycin. Thirty-day mortality was 48.3% (14/29).

Conclusions

ST147 ESBL-producing hvKp is associated with high mortality in COVID-19 patients. Strict microbiological surveillance and infection control measures are needed in this population.

Coinfections with Other Respiratory Pathogens among Patients with COVID-19

Emerging evidence indicates that severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-infected individuals are at an increased risk for coinfections; therefore, physicians need to be cognizant about excluding other treatable respiratory pathogens. Here, we report coinfection with SARS-CoV-2 and other respiratory pathogens in patients admitted to the coronavirus disease (COVID) care facilities of an Indian tertiary care hospital. From June 2020 through January 2021, we tested 191 patients with SARS-CoV-2 for 33 other respiratory pathogens using an fast track diagnostics respiratory pathogen 33 (FTD-33) assay. Additionally, information regarding other relevant respiratory pathogens was collected by reviewing their laboratory data. Overall, 13 pathogens were identified among patients infected with SARS-CoV-2, and 46.6% (89/191) of patients had coinfection with one or more additional pathogens. Bacterial coinfections (41.4% [79/191]) were frequent, with Staphylococcus aureus being the most common, followed by Klebsiella pneumoniae. Coinfections with SARS-CoV-2 and Pneumocystis jirovecii or Legionella pneumophila were also identified. The viral coinfection rate was 7.3%, with human adenovirus and human rhinovirus being the most common. Five patients in our cohort had positive cultures for Acinetobacter baumannii and K. pneumoniae, and two patients had active Mycobacterium tuberculosis infection. In total, 47.1% (90/191) of patients with coinfections were identified. The higher proportion of patients with coinfections in our cohort supports the systemic use of antibiotics in patients with severe SARS-CoV-2 pneumonia with rapid de-escalation based on respiratory PCR/culture results. The timely and simultaneous identification of coinfections can contribute to improved health of COVID-19 patients and enhanced antibiotic stewardship during the pandemic. IMPORTANCE Coinfections in COVID-19 patients may worsen disease outcomes and need further investigation. We found that a higher proportion of patients with COVID-19 were coinfected with one or more additional pathogens. A better understanding of the prevalence of coinfection with other respiratory pathogens in COVID-19 patients and the profile of pathogens can contribute to effective patient management and antibiotic stewardship during the current pandemic.

Contamination of Hospital Surfaces with Bacterial Pathogens under the Current COVID-19 Outbreak

The SARS-CoV-2 pandemic remains a global health issue for several reasons, such as the low vaccination rates and a lack of developed herd immunity to the evolution of SARS-CoV-2, as well as its potential inclination to elude neutralizing antibodies. It should be noted that the severity of the COVID-19 disease is significantly affected by the presence of co-infections. Comorbid conditions are caused not only by pathogenic and opportunistic microorganisms but also by some representatives of the environmental microbiome. The presence of patients with moderate and severe forms of the disease in hospitals indicates the need for epidemiological monitoring of (1) bacterial pathogens circulating in hospitals, especially the ESKAPE group pathogens, and (2) the microbiome of various surfaces in hospitals. In our study, we used combined methods based on PCR and NGS sequencing, which are widely used for epidemiological monitoring. Through this approach, we identified the DNA of pathogenic bacteria (Klebsiella pneumoniae, Pseudomonas aeruginosa, Staphylococcus aureus, CoNS, and Achromobacter spp.) on various surfaces. We also estimated the microbiome diversity of surfaces and identified the potential reservoirs of infections using 16S rRNA profiling. Although we did not assess the viability of identified microorganisms, our results indicate the possible risks of insufficient regular disinfection of surfaces, regardless of department, at the Infectious Diseases Hospital. Controlling the transmission of nosocomial diseases is critical to the successful treatment of COVID-19 patients, the rational use of antimicrobial drugs, and timely decontamination measures.

Genomic New Insights Into Emergence and Clinical Therapy of Multidrug-Resistant Klebsiella pneumoniae in Infected Pancreatic Necrosis

Infected pancreatic necrosis (IPN) is a key risk factor in the progression of severe acute pancreatitis, and use of antibiotics is one of the main clinical actions. However, early prophylactic or unreasonable use of antibiotics promotes drug resistance in bacteria and also delays optimum treatment. To explore genomic evidence of rational antibiotic use in intensive care units, we isolated Klebsiella pneumoniae from IPN samples that showed the highest positive-culture rate in 758 patients. Based on whole-genome sequencing from eight strains, 42 antibiotic-resistant genes were identified in the chromatin and 27 in the plasmid, which included classic resistance-mechanism factors such as β-lactamases [16.67% (7/42) in the chromatin and 25.93% (7/27) in the plasmid]. The K. pneumoniae isolates were identified to be resistant to multiple antibiotics used in clinics. In vivo and in vitro, ceftazidime-avibactam (CZA) plus aztreonam (ATM) (2.5:1) showed more significant antibacterial effectiveness than CZA alone. The isolated K. pneumoniae were of three different types according to the resistance phenotypes for CZA and ATM. Those co-harboring bla _NDM-5, bla _CTX-M-15, bla _OXA-1, and bla _SHV-187 showed higher resistance to CAZ than bla _NDM-5. Those co-harboring bla _CTX-M-65, bla _SHV-182, and bla _TEM-181 were significantly less resistant to β-lactam than to other extended-spectrum β-lactamases. However, β-lactamases were inhibited by avibactam (AVI), except for NDM-5. ATM plus AVI showed a significant inhibitory effect on K. pneumoniae, and the minimum dosage of ATM was < 1 mg/L. In conclusion, we propose that ATM plus AVI could be a major therapy for complex infectious diseases caused by multidrug-resistant K. pneumoniae.

Increasing frequency of Aminoglycoside-Resistant Klebsiella pneumoniae during the era of pandemic COVID-19

The emergence of multidrug resistance to aminoglycosides in K. pneumoniae isolates is a growing concern, especially during pandemic Coronavirus disease 2019 (COVID-19). The study identifies antibiotic resistance in K. pneumoniae isolated from tertiary hospitals during pandemic COVID-19. Among 220 clinical isolates, the total rate of K. pneumoniae was found to be 89 (40.5%). Phenotyping results confirmed the resistance of aminoglycoside antibiotics in 51 (23.2%) of K. pneumoniae isolates. PCR results confirmed the existence of one or more aminoglycoside genes in 82.3% of the 51 isolates. The rmtD gene was the highest-detected gene (66.7%), followed by aac(6')-Ib (45.1%), aph(3')-Ia (45.1%), rmtB (29.4%), armA (21.6%), aac(3)-II (7.8%), and rmtA (3) (11.8%). Significantly, higher resistance strains showed a higher prevalence (61.5%) of aminoglycoside genes (p < 0.05). During COVID-19, there is a higher risk of acquiring MDR bacterial infections, so the monitoring of multidrug resistant bacteria must be continuously undertaken to implement effective measures in infection control and prevention.

Carbapenem-Resistant Klebsiella pneumoniae Associated with COVID-19

Infections with carbapenem-resistant Enterobacteriaceae are emerging as an important challenge in healthcare settings. Currently, carbapenem-resistant Klebsiella pneumoniae (CRKP) are the species of CRE most commonly encountered in hospitals. CRKP is resistant to almost all available antimicrobial agents, and infections with CRKP have been associated with high rates of morbidity and mortality, particularly among persons with prolonged hospitalization exposed to invasive devices. We report nine patients hospitalized in an intensive care unit (ICU) with severe coronavirus disease 2019 (COVID-19) who developed invasive infections due to carbapenemase-producing Klebsiella pneumoniae (CP-Kp), KPC and OXA-48, strains that have not been previously identified in our hospital. Despite ceftazidime/avibactam therapy, five patients died. Coinfections can contribute to a poor prognosis for patients with COVID-19, especially for high-risk populations such as elderly patients. Therefore, it is crucial to establish a rigorous program of antibiotic administration in intensive care units.

The Complexity of Co-Infections in the Era of COVID-19

The current frequency of COVID-19 in a pandemic era ensures that co-infections with a variety of co-pathogens will occur. Generally, there is a low rate of bonafide co-infections in early COVID-19 pulmonary infection as currently appreciated. Reports of high co-infection rates must be tempered by limitations in current diagnostic methods since amplification technologies do not necessarily confirm live pathogen and may be subject to considerable laboratory variation. Some laboratory methods may not exclude commensal microbes. Concurrent serodiagnoses have long been of concern for accuracy in these contexts. Presumed virus co-infections are not specific to COVID-19. The association of influenza viruses and SARS-CoV-2 in co-infection has been considerably variable during influenza season. Other respiratory virus co-infections have generally occurred in less than 10% of COVID-19 patients. Early COVID-19 disease is more commonly associated with bacterial co-pathogens that typically represent usual respiratory micro-organisms. Late infections, especially among severe clinical presentations, are more likely to be associated with nosocomial or opportunistic pathogens given the influence of treatments that can include antibiotics, antivirals, immunomodulating agents, blood products, immunotherapy, steroids, and invasive procedures. As anticipated, hospital care carries risk for multi-resistant bacteria. Overall, co-pathogen identification is linked with longer hospital stay, greater patient complexity, and adverse outcomes. As for other viral infections, a general reduction in the use of empiric antibiotic treatment is warranted. Further insight into co-infections with COVID-19 will contribute overall to effective antimicrobial therapies and disease control.

Isolation and Characterization of a Novel Lytic Bacteriophage against the K2 Capsule-Expressing Hypervirulent Klebsiella pneumoniae Strain 52145, and Identification of Its Functional Depolymerase

Klebsiella pneumoniae is among the leading bacteria that cause nosocomial infections. The capsule of this Gram-negative bacterium is a dominant virulence factor, with a prominent role in defense and biofilm formation. Bacteriophages, which are specific for one bacterial strain and its capsule type, can evoke the lysis of bacterial cells, aided by polysaccharide depolymerase enzymes. In this study, we isolated and characterized a bacteriophage against the nosocomial K. pneumoniae 52145 strain with K2 capsular serotype. The phage showed a narrow host range and stable lytic activity, even when exposed to different temperatures or detergents. Preventive effect of the phage in a nasal colonization model was investigated in vivo. Phlyogenetic analysis showed that the newly isolated Klebsiella phage B1 belongs to the Webervirus genus in Drexlerviridae family. We identified the location of the capsule depolymerase gene of the new phage, which was amplified, cloned, expressed, and purified. The efficacy of the recombinant B1dep depolymerase was tested by spotting on K. pneumoniae strains and it was confirmed that the extract lowers the thickness of the bacterium lawn as it degrades the protective capsule on bacterial cells. As K. pneumoniae strains possessing the K2 serotype have epidemiological importance, the B1 phage and its depolymerase are promising candidates for use as possible antimicrobial agents.