Long-term clinical and economic benefits associated with the management of a nosocomial outbreak resulting from extended-spectrum beta-lactamase-producing Klebsiella pneumoniae:

The inhibition mechanism of co-cultured probiotics on biofilm formation of Klebsiella pneumoniae

AIMS

Klebsiella pneumoniae, an important opportunistic pathogen of nosocomial inflection, is known for its ability to form biofilm. The purpose of the current study is to assess how co- or mono-cultured probiotics affect K. pneumoniae's ability to produce biofilms and investigate the potential mechanisms by using a polyester nonwoven chemostat and a Caco-2 cell line.

METHODS AND RESULTS

Compared with pure cultures of Lactobacillus rhamnosus and Lactobacillus sake, the formation of K. pneumoniae biofilm was remarkably inhibited by the mixture of L. rhamnosus, L. sake, and Bacillus subtilis at a ratio of 5:5:1 by means of qPCR and FISH assays. In addition, Lactobacillus in combination with B. subtilis could considerably reduce the adherence of K. pneumoniae to Caco-2 cells by using inhibition, competition, and displacement assays. According to the RT-PCR assay, the adsorption of K. pneumoniae to Caco-2 cells was effectively inhibited by the co-cultured probiotics, leading to significant reduction in the expression of proinflammatory cytokines induced by K. pneumoniae. Furthermore, the HPLC and RT-PCR analyses showed that the co-cultured probiotics were able to successfully prevent the expression of the biofilm-related genes of K. pneumoniae by secreting plenty of organic acids as well as the second signal molecule (c-di-GMP), resulting in inhibition on biofilm formation.

CONCLUSION

Co-culture of L. sake, L. rhamnosus, and B. subtilis at a ratio of 5:5:1 could exert an antagonistic effect on the colonization of pathogenic K. pneumoniae by down-regulating the expression of biofilm-related genes. At the same time, the co-cultured probiotics could effectively inhibit the adhesion of K. pneumoniae to Caco-2 cells and block the expression of proinflammatory cytokines induced by K. pneumoniae.

Ten years of hand hygiene excellence: a summary of outcomes, and a comparison of indicators, from award-winning hospitals worldwide

BACKGROUND

Hand hygiene is a crucial measure for the prevention of healthcare-associated infections (HAIs). The Hand Hygiene Excellence Award (HHEA) is an international programme acknowledging healthcare facilities for their leadership in implementing hand hygiene improvement programmes, including the World Health Organisation's Multimodal Improvement Strategy. This study aimed at summarising the results of the HHEA campaign between 2010 and 2021 and investigating the relationship between different hand hygiene parameters based on data from participating healthcare facilities.

METHODS

A retrospective analysis was performed on datasets from HHEA forms, including data on hand hygiene compliance, alcohol-based handrub (ABHR) consumption, and Hand Hygiene Self-Assessment Framework (HHSAF) scores. Descriptive statistics were reported for each variable. The correlation between variables was inspected through Kendall's test, while possible non-linear relationships between hand hygiene compliance, ABHR consumption and HHSAF scores were sought through the Locally Estimated Scatterplot Smoothing or logistic regression models. A tree-structured partitioning model was developed to further confirm the obtained findings.

RESULTS

Ninety-seven healthcare facilities from 28 countries in three world regions (Asia-Pacific, Europe, Latin America) were awarded the HHEA and thus included in the analysis. HHSAF scores indicated an advanced hand hygiene promotion level (median 445 points, IQR 395-480). System change (100 [95-100] points) and institutional safety climate (85 [70-95] points) showed the highest and lowest score, respectively. In most cases, hand hygiene compliance was above 70%, with heterogeneity between countries. ABHR consumption above 20 millilitres per patient-day (ml/PD) was widely reported, with overall increasing trends. HHSAF scores were positively correlated with hand hygiene compliance (τ = 0.211, p = 0.007). We observed a positive correlation between compliance rates and ABHR consumption (τ = 0.193, p < 0.001), although the average predicted consumption was stable around 55-60 ml/PD for compliance rates above 80-85%. Logistic regression and partitioning tree analyses revealed that higher HHSAF scores were more likely in the high-ABHR consumption group at cut-offs around 57-59 ml/PD.

CONCLUSION

Ten years after its inception, the HHEA proves to be a valuable hand hygiene improvement programme in healthcare facilities worldwide. Consistent results were provided by the different hand hygiene indicators and the HHSAF score represents a valuable proxy measure of hand hygiene compliance.

Escalating antimicrobial resistance among Enterobacteriaceae: focus on carbapenemases

Introduction: Over the past few decades, antimicrobial resistance (AMR) has skyrocketed globally among bacteria within the Family Enterobacteriaceae (i.e. Enterobacter spp, Klebsiella spp, Escherichia coli, Proteus spp, Serratia marcescens, Citrobacter spp, and others). Enterobacteriaceae are intestinal flora and are important pathogens in nosocomial and community settings. Enterobacteriaceae spread easily between humans and may acquire AMR via plasmids or other mobile resistance elements. The emergence and spread of multidrug resistant (MDR) clones have greatly limited therapeutic options. Some infections are untreatable with existing antimicrobials.Areas covered: The authors discuss the escalation of CRE globally, the epidemiology and outcomes of CRE infections, the optimal therapy, and the potential role of several new antimicrobials to combat MDR organisms. An exhaustive search for literature related to Enterobacteriaceae was performed using PubMed, using the following key words: antimicrobial resistance; carbapenemases; Enterobacterales; Enterobacteriaceae; Klebsiella pneumoniae; Escherichia coli; global epidemiology; metallo-β-lactamases; multidrug resistance; New Delhi Metalloproteinase-1 (NDM-1); plasmidsExpert opinion: Innovation and development of new classes of antibacterial agents are critical to expand effective therapeutic options. The authors encourage the judicious use of antibiotics and aggressive infection-control measures are essential to minimize the spread of AMR.

Emergence of two distinct subpopulations from Klebsiella pneumoniae grown in the stimulated microgravity environment

Aim: To isolate and characterize the two phenotypically distinct subpopulations from Klebsiella pneumoniae clonal cultures grown in the simulate microgravity environment. Materials & methods: Here clonal culture of K. pneumoniae strain ATCC BAA-1705 was grown within a vertically rotating wall vessel bioreactor. Microscopic, colony staining, biofilm assays and quantitative proteomics were used to define the features of subpopulations. Results: Two subpopulations were isolated based on colony appearance and bacterial morphology and indicated the different capability of biofilm formation and antibiotics resistance. Conclusion: These findings would raise a possibility of understanding the adaptive roles of bacterial subpopulations formed under certain conditions from the viewpoint of population variation.

Cost-Analysis of Seven Nosocomial Outbreaks in an Academic Hospital

OBJECTIVES

Nosocomial outbreaks, especially with (multi-)resistant microorganisms, are a major problem for health care institutions. They can cause morbidity and mortality for patients and controlling these costs substantial amounts of funds and resources. However, how much is unclear. This study sets out to provide a comparable overview of the costs of multiple outbreaks in a single academic hospital in the Netherlands.

METHODS

Based on interviews with the involved staff, multiple databases and stored records from the Infection Prevention Division all actions undertaken, extra staff employment, use of resources, bed-occupancy rates, and other miscellaneous cost drivers during different outbreaks were scored and quantified into Euros. This led to total costs per outbreak and an estimated average cost per positive patient per outbreak day.

RESULTS

Seven outbreaks that occurred between 2012 and 2014 in the hospital were evaluated. Total costs for the hospital ranged between €10,778 and €356,754. Costs per positive patient per outbreak day, ranged between €10 and €1,369 (95% CI: €49-€1,042), with a mean of €546 and a median of €519. Majority of the costs (50%) were made because of closed beds.

CONCLUSIONS

This analysis is the first to give a comparable overview of various outbreaks, caused by different microorganisms, in the same hospital and all analyzed with the same method. It shows a large variation within the average costs due to different factors (e.g. closure of wards, type of ward). All outbreaks however cost considerable amounts of efforts and money (up to €356,754), including missed revenue and control measures.

Economic Evaluation of Interventions for Prevention of Hospital Acquired Infections: A Systematic Review

Objective

This systematic review sought to assess the costs and benefits of interventions preventing hospital-acquired infections and to evaluate methodological and reporting quality.

Methods

We systematically searched Medline via PubMed and the National Health Service Economic Evaluation Database from 2009 to 2014. We included quasi-experimental and randomized trails published in English or German evaluating the economic impact of interventions preventing the four most frequent hospital-acquired infections (urinary tract infections, surgical wound infections, pneumonia, and primary bloodstream infections). Characteristics and results of the included articles were extracted using a standardized data collection form. Study and reporting quality were evaluated using SIGN and CHEERS checklists. All costs were adjusted to 2013 US$. Savings-to-cost ratios and difference values with interquartile ranges (IQRs) per month were calculated, and the effects of study characteristics on the cost-benefit results were analyzed.

Results

Our search returned 2067 articles, of which 27 met the inclusion criteria. The median savings-to-cost ratio across all studies reporting both costs and savings values was US $7.0 (IQR 4.2–30.9), and the median net global saving was US $13,179 (IQR 5,106–65,850) per month. The studies’ reporting quality was low. Only 14 articles reported more than half of CHEERS items appropriately. Similarly, an assessment of methodological quality found that only four studies (14.8%) were considered high quality.

Conclusions

Prevention programs for hospital acquired infections have very positive cost-benefit ratios. Improved reporting quality in health economics publications is required.

Infection control implications of heterogeneous resistance mechanisms in carbapenem-resistant Enterobacteriaceae (CRE)

The Centers for Disease Control and Prevention (CDC) defines carbapenem-resistant Enterobacteriaceae (CRE) based upon a phenotypic demonstration of carbapenem resistance. However, considerable heterogeneity exists within this definitional umbrella. CRE may mechanistically differ by whether they do or do not produce carbapenemases. Moreover, patients can acquire CRE through multiple pathways: endogenously through antibiotic selective pressure on intestinal microbiota, exogenously through horizontal transmission or through a combination of these factors. Some evidence suggests that non-carbapenemase-producing CRE may be more frequently acquired by antibiotic exposure and carbapenemase-producing CRE via horizontal transmission, but definitive data are lacking. This review examines types of CRE resistance mechanisms, antibiotic exposure and horizontal transmission pathways of CRE acquisition, and the implications of these heterogeneities to the development of evidence-based CRE healthcare epidemiology policies. In our Expert Commentary & Five-Year View, we outline specific nosocomial CRE knowledge gaps and potential methodological approaches for their resolution.

Differential impact of infection control strategies on rates of resistant hospital-acquired pathogens in critically ill surgical patients

BACKGROUND

There were two major outbreaks of multi-drug resistant Acinetobacter baumannii (MDRA) in our general surgery and trauma intensive care units (ICUs) in 2004 and 2011. Both required aggressive multi-faceted interventions to control. We hypothesized that the infection control response may have had a secondary benefit of reducing rates of methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant Enterococcus (VRE), and Clostridium difficile (C. diff).

METHODS

We analyzed data retrospectively from a prospective infection control database at a major university hospital and calculated the incidence rates of nosocomial MRSA, VRE, and C. diff before and after the two MDRA outbreaks (2004 and 2011) in the general surgery and trauma ICUs, and two unaffected control ICUs: thoracic surgery ICU and medical ICU. We tracked incidence rates in 6 mos segments for 24 mos per outbreak and created a composite variable of "any resistant pathogen" for comparison.

RESULTS

The incidence rates of "any resistant pathogen" were significantly lower in the general surgery ICU after both outbreaks (24 to 11 cases per 1000 patient days in 2004, p=0.045 and 7.7 ->4.0 cases per 1000 patient days in 2011, p=0.04). This did not persist after 6 mos. The trauma ICU's rate of "any resistant pathogen" did not change after either outbreak (16 ->16.5 cases per 1000 patient days in 2004, p=0.44 and 4.6 ->1.9 cases per 1000 patient days in 2011, p=0.41). The rates in the control ICUs were unchanged during the study periods.

CONCLUSIONS

Rates of resistant pathogens were lower in the general surgery ICU after response to MDRA outbreaks in both 2004 and 2011 although the rates increased again with time. There were no changes in rates of resistant pathogens in the trauma ICU after MDRA outbreaks in 2004 and 2011. Outbreak responses may have a differential impact in general surgery ICU versus trauma ICUs.

Prevalence and characteristics of extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae isolated from rural well water in Taian, China, 2014

The production of extended-spectrum beta-lactamase (ESBL) is one of the major antimicrobial resistance mechanisms in Enterobacteriaceae, and the increasing number of ESBL-producing Enterobacteriaceae isolated from water environments has posed a serious threat to the public health. The study aimed to analyze prevalence and characterization of ESBL-producing Enterobacteriaceae from rural well waters in Taian, China. A total of 10 isolates expressing an ESBL phenotype, including 9 Escherichia coli (E. coli) and 1 Klebsiella pneumoniae (K. pneumoniae) was obtained from 4 (4%) out of the 100 sampled wells. ESBL genotype revealed that 9 expressed CTX-M-15 and 1 produced CTX-M-27. Five out of 8 ESBL-producing E. coli expressing CTX-M-15 belonged to ST10, which are mostly detected from human feces in China. Importantly, the only strain of CTX-M-27-producing E. coli belonged to multi-locus sequence type B2:131 (ST131), which may be related with severe infection in humans and animals.

Antimicrobial resistance in hospital-acquired gram-negative bacterial infections

Aerobic gram-negative bacilli, including the family of Enterobacteriaceae and non-lactose fermenting bacteria such as Pseudomonas and Acinetobacter species, are major causes of hospital-acquired infections. The rate of antibiotic resistance among these pathogens has accelerated dramatically in recent years and has reached pandemic scale. It is no longer uncommon to encounter gram-negative infections that are untreatable using conventional antibiotics in hospitalized patients. In this review, we provide a summary of the major classes of gram-negative bacilli and their key mechanisms of antimicrobial resistance, discuss approaches to the treatment of these difficult infections, and outline methods to slow the further spread of resistance mechanisms.

Multidrug resistance found in extended-spectrum beta-lactamase-producing Enterobacteriaceae from rural water reservoirs in Guantao, China

Extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae have been isolated from humans and animals across the world. However, data on prevalence of ESBL-producing Enterobacteriaceae from rural water reservoirs is limited. This study aimed to isolate and characterize ESBL-producing Enterobacteriaceae in rural water reservoirs in Guantao, China. ESBL-producing Enterobacteriaceae were found in 5 (16.7%) of 30 sampled rural water reservoirs. Sixty-six individual isolates expressing an ESBL phenotype were obtained in the present study. Species identification showed that 42 representatives of Escherichia coli, 17 Klebsiella pneumoniae, 4 Raoultella planticola, and 3 Enterobacter cloacae. Twenty isolates contained a single bla gene, including CTX-M (17 strains), TEM (2 strains), and SHV (1 strain). Forty-six isolates contained more than one type of beta-lactamase genes. ESBL-producing Enterobacteriaceae isolated in this study were all multidrug resistant. These findings indicated that the serious contamination of ESBL-producing Enterobacteriaceae in rural water reservoirs existed in Guantao, China.

Lipid-based signaling modulates DNA repair response and survival against Klebsiella pneumoniae infection in host cells and in mice

Klebsiella pneumoniae causes serious infections in the urinary tract, respiratory tract, and blood. Lipid rafts, also known as membrane microdomains, have been linked to the pathogenesis of bacterial infection. However, whether lipid rafts affect K. pneumoniae internalization into host cells remains unknown. Here, we show for the first time that K. pneumoniae was internalized into lung cells by activating lipid rafts. Disrupting lipid rafts by methyl-β-cyclodextrin inhibited pathogen internalization, impairing host defense. A deficient mutant of capsule polysaccharide (CPS) showed a higher internalization rate than a wild-type strain, indicating that CPS may inhibit bacterial entry to host cells. Furthermore, lipid rafts may affect the function of extracellular regulated kinase (ERK)-1/2, and knocking down ERK1/2 via short, interfering RNA increased apoptosis in both alveolar macrophages and epithelial cells after infection. To gain insights into bacterial pathogenesis, we evaluated the impact of lipid rafts on DNA integrity, and showed that raft aggregates also affect DNA damage and DNA repair responses (i.e., 8-oxoguanine DNA glycosylase [Ogg1]) through the regulation of reactive oxygen species. Importantly, cells overexpressing Ogg1 demonstrated reduced cytotoxicity during bacterial infection. Taken together, these results suggest that lipid rafts may modulate bacterial internalization, thereby affecting DNA damage and repair, which is critical to host defense against K. pneumoniae.

Prompt control of an outbreak caused by extended-spectrum β-lactamase-producing Klebsiella pneumoniae in a neonatal intensive care unit

OBJECTIVES

To assess the effectiveness of a set of multidisciplinary interventions aimed at limiting patient-to-patient transmission of extended-spectrum β-lactamase-producing Klebsiella pneumoniae (ESBL-KP) during a neonatal intensive care unit (NICU) outbreak, and to identify risk factors associated with ESBL-KP colonization and disease in this setting.

STUDY DESIGN

A 61-infant cohort present in the NICU during an outbreak of ESBL-KP from April 26, 2011, to May 16, 2011, was studied. Clinical characteristics were compared in infected/colonized infants and unaffected infants. A multidisciplinary team formulated an outbreak control plan that included (1) staff reeducation on recommended infection prevention measures; (2) auditing of hand hygiene and environmental services practices; (3) contact precautions; (4) cohorting of infants and staff; (5) alleviation of overcrowding; and (6) frequent NICU-wide screening cultures. Neither closure of the NICU nor culturing of health care personnel was instituted.

RESULTS

Eleven infants in this level III NICU were infected/colonized with ESBL-KP. The index case was an 18-day-old infant born at 25 weeks' gestation who developed septicemia from ESBL-KP. Two other infants in the same room developed sepsis from ESBL-KP within 48 hours; both expired. Implementation of various infection prevention strategies resulted in prompt control of the outbreak within 3 weeks. The ESBL-KP isolates presented a single clone that was distinct from ESBL-KP identified previously in other units. Being housed in the same room as the index infant was the only risk factor identified by logistic regression analysis (P = .002).

CONCLUSION

This outbreak of ESBL-KP affected 11 infants and was associated with 2 deaths. Prompt control with eradication of the infecting strain from the NICU was achieved with multidisciplinary interventions based on standard infection prevention practices.

One-day point prevalence of emerging bacterial pathogens in a nationwide sample of 62 German hospitals in 2012 and comparison with the results of the one-day point prevalence of 2010

BACKGROUND

Antibiotic resistance of bacterial pathogens is an emerging problem worldwide. To combat multidrug resistant organisms (MRDOs) networks of care providers have been established in all states in Germany. The HICARE-network, a project to combat MRDOs, founded by the Federal Ministry of Education and Research, has published data from 2010 of a voluntary, German-wide, multicenter point-prevalence survey in 2011 conducted in collaboration with the German Society of Hospital Hygiene. The aim of the present survey was the re-evaluation of the situation in 2012.

METHOD

The survey was conducted as a voluntary, anonymous, point-prevalence in May 2012 using routine data of microbiological diagnostics of the hospitals. As in the former survey of 2010 it was differentiated between primary, secondary and tertiary care hospitals and only data from intensive care units, surgical and medical wards were collected. Based on the survey form used in 2010, an updated version was used including more pathogens and corrected issues observed in the former survey. Methicillin-resistant Staphylococcus aureus (MRSA) (total as well as separated in hospital-acquired (HA), community-acquired (CA) and lifestock-associated (LA) MRSA), vancomycin resistant Staphylococcus aureus (VRSA/GRSA), vancomycin resistant Enterococcus faecalis resp. Enterococcus faecium (VR-E. faecalis resp. VR-E. faecium), extended-spectrum-beta-lactamase-building (ESBL) E. coli (ESBL-EC) and Klebsiella pneumoniae (ESBL-KP), multiresistant Acinetobacter spp. (MAB), multiresistant Pseudomonas spp. (MRP), carbapenemase-producing Enterobacteriaceae (CRE) as well as Clostridium difficile (CD) infections and severe infections requiring ICU-treatment were included in the survey along with additional data on screening strategy, the equipment with infection control staff and possible confounders.

RESULTS

Out of 1,550 hospitals asked to participate, 62 returned data (4%). Data from 56 hospitals including primary (26), secondary (20) and tertiary (10) care hospitals were analyzable (3.6%). The most frequently reported organisms were MRSA 1.53% [CI95: 1.32-1.75], followed by CDAD 1.30% [CI95: 1.11-1.50], ESBL-EC 0.97% [CI95: 0.80-1.14], and ESBL-KP 0.27% [CI95: 0.18-0.36], regardless of the level of care. Prevalence of MRDOs depended on the level of care and on the type of ward, as expected. Overall prevalence was highest on intensive care wards, and prevalences were remarkably high on medical wards compared to surgical wards. All tertiary care providers employed their own infection control nurse, while only ~70% of the secondary and primary care hospitals did. Surprisingly, in two of the ten participating tertiary care providers neither an internal nor an external infection control doctor was available.

DISCUSSION

With more than 13,000 patients in 56 hospitals distributed all over Germany, the survey included more than three times as many patients as the first survey and therefore not only adds valuable information about the epidemiology of emerging nosocomial pathogens, but also helps to raise awareness of the problem of antibacterial resistance in Germany. The prevalences reported seem to be comparable to the results of the former survey and of other surveys published. Some hospitals reported to have no infection control personnel available at all. This statement is in line with another survey published in this issue.

Klebsiella pneumoniae and type 3 fimbriae: nosocomial infection, regulation and biofilm formation

The Gram-negative opportunistic pathogen Klebsiella pneumoniae is responsible for causing a spectrum of nosocomial and community-acquired infections. Globally, K. pneumoniae is a frequently encountered hospital-acquired opportunistic pathogen that typically infects patients with indwelling medical devices. Biofilm formation on these devices is important in the pathogenesis of these bacteria, and in K. pneumoniae, type 3 fimbriae have been identified as appendages mediating the formation of biofilms on biotic and abiotic surfaces. The factors influencing the regulation of type 3 fimbrial gene expression are largely unknown but recent investigations have indicated that gene expression is regulated, at least in part, by the intracellular levels of cyclic di-GMP. In this review, we have highlighted the recent studies that have worked to elucidate the mechanism by which type 3 fimbrial expression is controlled and the studies that have established the importance of type 3 fimbriae for biofilm formation and nosocomial infection by K. pneumoniae.