A simultaneous outbreak on a neonatal unit of two strains of multiply antibiotic resistant Klebsiella pneumoniae controllable only by ward closure

Reservoirs of Nosocomial Pathogens in Intensive Care Units: A Systematic Review

Background

Nosocomial pathogens are known to exacerbate morbidity and mortality in contemporary critical healthcare. Hospital fomites, which include inanimate surfaces, have been identified as "breeding grounds" for pathogens that cause nosocomial infections. This systematic review aimed to deliver incisive insights on nosocomial pathogens in intensive care units (ICUs) and the role of fomites as potential reservoirs for their transmission.

Method

An extensive exploration of electronic databases, including PubMed and Scopus, from 1990 to 2023, was carried out between 25th and 29th May 2023, per standard PRISMA guidelines. Information were extracted from articles that reported on fomites in the ICU. Studies that did not quantitatively report the fomite contamination, and those that exclusively took samples from patients in the ICU were excluded from the analysis.

Results

About 40% of the total samples collected on fomites from all the studies yielded microbial growth, with species of Staphylococcus being the most predominant. Other prevalent microbes were Acinetobacter baumannii, Escherichia coli, Klebsiella pneumoniae, Candida spp., Enterococcus sp., and Enterobacter sp. The neonatal intensive care unit (NICU) had the highest proportion of contaminated fomites. Among known fomites, the sphygmomanometer exhibited a 100% detection rate of nosocomial pathogens. This included E. aerogenes, Staphylococcus aureus, coagulase-negative Staphylococci (CoNS), E. coli, and K. pneumoniae. Multidrug-resistant (MDR) bacteria, such as methicillin-resistant S. aureus (MRSA), vancomycin-resistant Enterococci (VRE), extended-spectrum beta-lactamase (ESBL)-producing E. coli, and MDR Pseudomonas aeruginosa were commonly isolated on fomites in the ICUs.

Conclusion

Many fomites that are readily used in patient care in the ICU harbour nosocomial pathogens. The most common fomite appeared to be mobile phones, sphygmomanometers, and stethoscopes, with Staphylococcus being the most common contaminant. Consequently, the need for rigorous disinfection and sterilization protocols on fomites in the ICU cannot be overemphasized. Additionally, heightened awareness on the subject among health professionals is crucial to mitigating the risk and burden of nosocomial infections caused by drug-resistant bacteria.

The efficiency of cleaning in intensive care units: A systematic review

OBJECTIVES

This review aims to analyze the studies on cleaning practices and the efficiency of the cleaning carried out in environments that have a great risk of resistant microorganism infection, such as intensive care units.

METHODS

In this study, a retrospective literature review was undertaken of the relevant publications between the years 2005 and 2020, using the keywords "Cross Infection, Infection Control, Multidrug-Resistant Bacteria, Intensive Care, Room Cleaning, Environmental Cleaning, Hospital-Associated Infection"; using the international databases Pubmed, CINAHL and EBSCO and domestic database ULAKBIM on search engines. Titles and abstracts of all relevant articles found on electronic searches were reviewed by the researchers independently. The Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols guideline and Patient, Intervention, Comparison, Outcomes, Study design model were used in analysing the studies.

RESULTS

The selected studies were reviewed in four main categories: Materials used in cleaning, the period between taking environmental samples, cleaning methods, and the efficiency of cleaning. Among the studies included herein, eight were randomized controlled trials, three were retrospective intervention studies, two were case-control studies and one was a retrospective cohort study.

CONCLUSIONS

Today, the assessment of cleaning in environments can be evaluated by different methods, but there are advantages and disadvantages of these methods. Therefore, in the relevant literature, it is suggested that cleaning must be evaluated by several methods, not only one. Also, training the staff that carries out the cleaning and rewarding correct behavior by giving feedback are important approaches to increase the efficiency of cleaning. It is suggested that cleaning must be carried out every day, regularly with effective methods and equipment; frequency of cleaning during epidemics must be increased, institutions must prepare cleaning manuals according to evidence-based guidelines that are recognized at an international level.

The characteristics and roles of antimicrobial peptides as potential treatment for antibiotic-resistant pathogens: a review

The emergence of antibiotic-resistant bacteria has become a significant and ever-increasing threat to global public health, increasing both morbidity and mortality rates, and the financial burden on health services. Infection by drug-resistant bacteria is anticipated to contribute to the demise of almost 10 million people by the year 2050 unless a competent and effective response is devised to engage with this issue. The emergence and spread of resistance are commonly caused by the excessive or inappropriate use of antibiotics and substandard pharmaceuticals. It arises when pathogens adapt to different conditions and develop self-defence mechanisms. Currently, novel antimicrobial peptides (AMPs) have been reported to be the sole cure for some clinical cases of infectious diseases such as sepsis and skin infections, although these agents may, on occasion, require administration together with an adjunctive low-dose antibiotic. Although AMPs are a promising alternative form of anti-microbial therapy and easily applied in the medical sector, they still have limitations that should not be taken lightly. Hence, this review explores the characteristics, advantages and disadvantages of AMPs for their potential in treating antibiotic-resistant pathogens.

The efficiency of cleaning in intensive care units: A systematic review

OBJECTIVES

This review aims to analyze the studies on cleaning practices and the efficiency of the cleaning carried out in environments that have a great risk of resistant microorganism infection, such as intensive care units.

METHODS

In this study, a retrospective literature review was undertaken of the relevant publications between the years 2005 and 2020, using the keywords "Cross Infection, Infection Control, Multidrug-Resistant Bacteria, Intensive Care, Room Cleaning, Environmental Cleaning, Hospital-Associated Infection"; using the international databases Pubmed, CINAHL and EBSCO and domestic database ULAKBIM on search engines. Titles and abstracts of all relevant articles found on electronic searches were reviewed by the researchers independently. The Preferred Reporting Items for Systematic Review and Meta-Analysis Protocols guideline and Patient, Intervention, Comparison, Outcomes, Study design model were used in analysing the studies.

RESULTS

The selected studies were reviewed in four main categories: Materials used in cleaning, the period between taking environmental samples, cleaning methods, and the efficiency of cleaning. Among the studies included herein, eight were randomized controlled trials, three were retrospective intervention studies, two were case-control studies and one was a retrospective cohort study.

CONCLUSIONS

Today, the assessment of cleaning in environments can be evaluated by different methods, but there are advantages and disadvantages of these methods. Therefore, in the relevant literature, it is suggested that cleaning must be evaluated by several methods, not only one. Also, training the staff that carries out the cleaning and rewarding correct behavior by giving feedback are important approaches to increase the efficiency of cleaning. It is suggested that cleaning must be carried out every day, regularly with effective methods and equipment; frequency of cleaning during epidemics must be increased, institutions must prepare cleaning manuals according to evidence-based guidelines that are recognized at an international level.

Genetic relatedness of Gram-negative bacteria colonizing gut and skin of neonates and mother's own milk

OBJECTIVE

We described colonization of mother's own milk with Gram-negative bacteria and its relationship with neonatal colonization.

STUDY DESIGN

Gram-negative bacteria isolated from weekly collected stool, skin and mother's own milk of hospitalized preterm (n = 49) and healthy term neonates (n = 20) were genotyped. Colonization-related factors were determined by logistic regression.

RESULTS

Gram-negative bacteria were isolated from mother's own milk of 22.4% (n = 11) and 15% (n = 3) of mothers of preterm and term neonates, respectively. According to pulsed-field gel electrophoresis genetically similar strains were present in mother's own milk and gut of 8.2% (n = 4) of mother-preterm neonate, but none of mother-term neonate pairs. In three of four late-onset sepsis caused by Gram-negative bacteria, colonization of gut, but not mother's own milk, with invasive species preceded late-onset sepsis.

CONCLUSIONS

Colonization of mother's own milk with Gram-negative bacteria is uncommon and transmission to neonatal gut may occur in less than one-tenth of neonate-mother pairs.

The Role of Patient Care Items as a Fomite in Healthcare-Associated Outbreaks and Infection Prevention

Patient-care items can serve as a source or reservoir for healthcare-associated pathogens in hospitals. We reviewed healthcare- associated outbreaks from medical equipment and provide infection prevention recommendations. Multiple healthcare-associated outbreaks via a contaminated patient-care item were identified, including infections with multidrug-resistant organisms. The type of patient care items implicated as a fomite causing healthcare-associated infections (HAIs) has changed over time. Patient populations at risk were most commonly critically ill patients in adult and neonatal intensive care units. Most fomite related healthcare-associated outbreaks were due to inappropriate disinfection practices. Repeated healthcare-associated outbreaks via medical equipment highlight the need for infectious disease professionals to understand that fomites/medical devices may be a source of HAIs. The introduction of new and more complex medical devices will likely increase the risk that such devices serve as a source of HAIs. Assuring appropriate cleaning and disinfection or sterilization of medical equipment is necessary to prevent future fomite-associated outbreaks.

When are pathogen genome sequences informative of transmission events?

Recent years have seen the development of numerous methodologies for reconstructing transmission trees in infectious disease outbreaks from densely sampled whole genome sequence data. However, a fundamental and as of yet poorly addressed limitation of such approaches is the requirement for genetic diversity to arise on epidemiological timescales. Specifically, the position of infected individuals in a transmission tree can only be resolved by genetic data if mutations have accumulated between the sampled pathogen genomes. To quantify and compare the useful genetic diversity expected from genetic data in different pathogen outbreaks, we introduce here the concept of ‘transmission divergence’, defined as the number of mutations separating whole genome sequences sampled from transmission pairs. Using parameter values obtained by literature review, we simulate outbreak scenarios alongside sequence evolution using two models described in the literature to describe transmission divergence of ten major outbreak-causing pathogens. We find that while mean values vary significantly between the pathogens considered, their transmission divergence is generally very low, with many outbreaks characterised by large numbers of genetically identical transmission pairs. We describe the impact of transmission divergence on our ability to reconstruct outbreaks using two outbreak reconstruction tools, the R packages outbreaker and phybreak, and demonstrate that, in agreement with previous observations, genetic sequence data of rapidly evolving pathogens such as RNA viruses can provide valuable information on individual transmission events. Conversely, sequence data of pathogens with lower mean transmission divergence, including Streptococcus pneumoniae, Shigella sonnei and Clostridium difficile, provide little to no information about individual transmission events. Our results highlight the informational limitations of genetic sequence data in certain outbreak scenarios, and demonstrate the need to expand the toolkit of outbreak reconstruction tools to integrate other types of epidemiological data.

The increasing availability of genetic sequence data has sparked an interest in using pathogen whole genome sequences to reconstruct the history of individual transmission events in an infectious disease outbreak. However, such methodologies rely on pathogen genomes mutating rapidly enough to discriminate between infected individuals, an assumption that remains to be investigated. To determine pathogen outbreaks for which genetic data is expected to be informative of transmission events, we introduce here the concept of ‘transmission divergence’, defined as the number of mutations separating pathogen genome sequences sampled from transmission pairs. We characterise transmission divergence of ten major outbreak causing pathogens using simulations and find significant variation between diseases, with viral outbreaks generally exhibiting higher transmission divergence than bacterial ones. We reconstruct these outbreaks using the R-packages outbreaker and phybreak and find that genetic sequence data, though useful for rapidly evolving pathogens, provides little to no information about outbreaks with low transmission divergence, such as Streptococcus pneumoniae and Shigella sonnei. Our results demonstrate the need to incorporate other sources of outbreak data, such as contact tracing data and spatial location data, into outbreak reconstruction tools.

Impact of single room design on the spread of multi-drug resistant bacteria in an intensive care unit

Background

Cross-transmission of nosocomial pathogens occurs frequently in intensive care units (ICU). The aim of this study was to investigate whether the introduction of a single room policy resulted in a decrease in transmission of multidrug-resistant (MDR) bacteria in an ICU.

Methods

We performed a retrospective study covering two periods: between January 2002 and April 2009 (old-ICU) and between May 2009 and March 2013 (new-ICU, single-room). These periods were compared with respect to the occurrence of representative MDR Gram-negative bacteria. Routine microbiological screening, was performed on all patients on admission to the ICU and then twice a week. Multi-drug resistance was defined according to a national guideline. The first isolates per patient that met the MDR-criteria, detected during the ICU admission were included in the analysis. To investigate the clonality, isolates were genotyped by DiversiLab (bioMérieux, France) or Amplified Fragment Length Polymorphism (AFLP). To guarantee the comparability of the two periods, the ‘before’ and ‘after’ periods were chosen such that they were approximately identical with respect to the following factors: number of admissions, number of beds, bed occupancy rate, per year and month.

Results

Despite infection prevention efforts, high prevalence of MRD bacteria continue to occur in the original facility. A marked and sustained decrease in the prevalence of MDR-GN bacteria was observed after the migration to the new ICU, while there appear to be no significant changes in the other variables including bed occupancy and numbers of patient admissions.

Conclusion

Single room ICU design contributes significantly to the reduction of cross transmission of MRD-bacteria.

Emerging extended-spectrum β-lactamase-producing Klebsiella pneumoniae causing community-onset urinary tract infections: a case-control-control study

The aim of this study was to determine the epidemiology and risk factors associated with community-onset urinary tract infections (CO-UTIs) due to extended-spectrum β-lactamase-producing Klebsiella pneumoniae (ESBL-Kp). A cohort study including all consecutive patients with K. pneumoniae CO-UTI identified from January 2010 to December 2014 was conducted. Patients with CO-UTI due to ESBL-Kp were then included as cases in a retrospective case-control-control study; controls were outpatients with CO-UTI caused by non-ESBL-producing Escherichia coli and K. pneumoniae (non-ESBL-Ec and non-ESBL-Kp, respectively). Each control was matched in a 2:1 ratio according to patient age, sex and year of isolation. Genotyping confirming ESBL was performed by multiplex PCR and sequencing. The prevalence of ESBL-Kp CO-UTIs, calculated among all K. pneumoniae CO-UTIs, increased from 2.4% in 2010 to 10.3% in 2014 (P = 0.01). Among cases, 63.8% were truly community-acquired, and CTX-M-15 was the predominant β-lactamase enzyme type (79.3%). A total of 83 cases and 319 controls were studied. Being a nursing home resident [odds ratio (OR) = 8.8, 95% confidence interval (CI) 2.6-29.4] and previous cephalosporin use (OR = 4.01, 95% CI 1.8-9.2) were risk factors independently associated with CO-UTI due to ESBL-Kp. In conclusion, the prevalence of CO-UTIs due to ESBL-Kp is increasing. In most cases, ESBL-Kp CO-UTIs are community-acquired and produce CTX-M-15 β-lactamase. Exposure to cephalosporins and being a nursing home resident were risk factors associated with ESBL-Kp CO-UTIs. CTX-M-15-producing K. pneumoniae isolates are emerging in the community.

The emergence of carbapenem resistant Klebsiella pneumoniae in Malaysia: correlation between microbiological trends with host characteristics and clinical factors

Background

Carbapenem resistant Enterobacteriaceae is a growing concern worldwide including Malaysia. The emergence of this pathogen is worrying because carbapenem is one of the 'last-line' antibiotics. The main objective of this study was to determine the prevalence of genetic mechanisms and clinical risk factors of carbapenem resistant Klebsiella pneumoniae (K. pneumoniae) in Malaysia.

Methods

In this study, seventeen carbapenem resistant K. pneumoniae strains isolated from a tertiary teaching hospital in 2013 were studied. Minimal inhibitory concentration (MIC) of the bacterial strains was determined and genes associated with carbapenemases and extended-spectrum-beta-lactamases (ESBLs) were sequenced and compared with the closest representatives published in public domains. All strains were also sub-typed using pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST). Statistical analyses were performed to determine the correlation between risk factors for acquiring carbapenem resistant K. pneumoniae and in-hospital mortality.

Results

The predominant carbapenemase was bla_OXA-48, detected in 12 strains (70.59%). Other carbapenemases detected in this study were bla_KPC-2, bla_IMP-8, bla_NMC-A and bla_NDM-1. Nine different pulsotypes were identified and nine strains which were affiliated with ST101, the predominant sequence type had similar PFGE patterns (similarity index of 85%). Based on univariate statistical analysis, resistance to imipenem and usage of mechanical ventilation showed a statistically significant effect separately to in-hospital mortality.

Conclusion

The diverse genetic mechanisms harbored by these carbapenem resistant K. pneumoniae facilitates its spread and complicates its detection. Thus, correlation between microbiological trends with host characteristics and clinical factors will provide a better insight of rational treatment strategies and pathogen control.

Outbreak of multidrug-resistant Escherichia coli sequence type 131 in a neonatal intensive care unit: efficient active surveillance prevented fatal outcome

BACKGROUND

Outbreaks of infections with multidrug-resistant bacteria in neonatal intensive care units (NICUs) pose a major threat, especially to extremely preterm infants. This study describes a 35-day outbreak of multidrug-resistant Escherichia coli (E. coli) in a tertiary-level NICU in Germany.

AIM

To underline the importance of surveillance policies in the particularly vulnerable cohort of preterm infants and to describe the efficacy of outbreak control strategies.

METHODS

Data were collected retrospectively from medical reports. Infants and environment were tested for E. coli.

FINDINGS

The outbreak affected a total of 13 infants between 25(+1) and 35(+0) weeks of gestation with seven infants showing signs of infection. The outbreak strain was identified as E. coli sequence type 131. Environmental screening provided no evidence for an environmental source. Through colonization surveillance and immediate and adequate treatment of potentially infected preterm infants, no fatalities occurred. Outbreak control was achieved by strict contact precautions, enhanced screening and temporary relocation of the NICU. Relocation and reconstruction improved the NICU's structural layout, focusing on isolation capacities. Follow-up indicated carriage for several months in some infants.

CONCLUSION

Routine surveillance allowed early detection of the outbreak. The identification of carriers of the outbreak strain was successfully used to direct antibiotic treatment in case of infection. Enhanced hygienic measures and ward relocation were instrumental in controlling the outbreak.

Outbreaks of extended spectrum beta-lactamase-producing Enterobacteriaceae in neonatal intensive care units: a systematic review

OBJECTIVE

To establish the number of outbreaks of extended spectrum beta-lactamase (ESBL) producing organisms in neonatal intensive care units (NICUs), to determine causes, mortality rates, proportions of infants colonised and infected and the interventions that terminated outbreaks.

METHODS

A systematic review of the literature in English, Spanish and French was undertaken with searches in four databases. The review conformed to the PRISMA guidelines, and the data extraction was modelled on the ORION criteria for studies of nosocomial infection.

RESULTS

75 studies fulfilled the inclusion criteria. There were 1185 cases of colonisation, 860 infections and 139 deaths. The median outbreak duration was 6.2 months (IQR 2.0-7.5 months). Klebsiella pneumoniae was the most frequently implicated pathogen. Understaffing was the most frequent risk factor for outbreaks. The most commonly identified source was admission of an ESBL-colonised infant with subsequent horizontal dissemination. The main interventions described were improved infection-control procedures and screening of staff and the environment. 26 studies were included in the quantitative analysis. Random effects meta-analysis indicated high mortality rates in infants who developed infection (31%, 95% CI 20% to 43%).

CONCLUSION

ESBL outbreaks in NICUs are associated with significant mortality and prolonged disruption. Understaffing is a major risk factor, but is infrequently addressed by interventions. Poor infection-control procedures are frequently implicated as contributing to ESBL spread. Better reporting of outbreaks may help clarify the role for routine ESBL screening in NICUs.

The negative impact of antibiotic resistance

Antibacterial therapy is one of the most important medical developments of the twentieth century; however, the spread of resistance in healthcare settings and in the community threatens the enormous gains made by the availability of antibiotic therapy. Infections caused by resistant bacteria lead to up to two-fold higher rates of adverse outcomes compared with similar infections caused by susceptible strains. These adverse outcomes may be clinical or economic and reflect primarily the failure or delay of antibiotic treatment. The magnitude of these adverse outcomes will be more pronounced as disease severity, strain virulence, or host vulnerability increases. The negative impacts of antibacterial resistance can be measured at the patient level by increased morbidity and mortality, at the healthcare level by increased resource utilization, higher costs and reduced hospital activity and at the society level by antibiotic treatment guidelines favouring increasingly broad-spectrum empiric therapy. In this review we will discuss the negative impact of antibiotic resistance on patients, the healthcare system and society.

Use of ward closure to control outbreaks among hospitalized patients in acute care settings: a systematic review

BACKGROUND

Though often used to control outbreaks, the efficacy of ward closure is unclear. This systematic review sought to identify studies defining and describing ward closure in outbreak control and to determine impact of ward closure as an intervention on outbreak containment.

METHODS

We searched these databases with no language restrictions: MEDLINE, 1946 to 7 July 2014; EMBASE, 1974 to 7 July 2014; CINAHL, 1937 to 8 July 2014; and Cochrane Database of Systematic Reviews, 2005 to May 2014. We also searched the following: IndMED; LILACS; reference lists from retrieved articles; conference proceedings; and websites of the CDCP, the ICID, and the WHO. We included studies of patients hospitalized in acute care facilities; used ward closure as a control measure; used other control measures; and discussed control of the outbreak(s) under investigation. A component approach was used to assess study quality.

RESULTS

We included 97 English and non-English observational studies. None included a controlled comparison between ward closure and other interventions. We found that ward closure was often used as part of a bundle of interventions but could not determine its direct impact separate from all the other interventions whether used in parallel or in sequence with other interventions. We also found no universal definition of ward closure which was widely accepted.

CONCLUSIONS

With no published controlled studies identified, ward closure for control of outbreaks remains an intervention that is not evidence based and healthcare personnel will need to continue to balance the competing risks associated with its use, taking into consideration the nature of the outbreak, the type of pathogen and its virulence, mode of transmission, and the setting in which it occurs. Our review has identified a major research gap in this area.

Clinical and Molecular Epidemiology of Extended-Spectrum Beta-Lactamase-Producing Klebsiella spp.: A Systematic Review and Meta-Analyses

Healthcare-related infections caused by extended-spectrum beta-lactamase (ESBL)-producing Klebsiella spp. are of major concern. To control transmission, deep understanding of the transmission mechanisms is needed. This systematic review aimed to identify risk factors and sources, clonal relatedness using molecular techniques, and the most effective control strategies for ESBL-producing Klebsiella spp. A systematic search of PubMed, Embase, and Outbreak Database was performed. We identified 2771 articles from November 25th, 1960 until April 7th, 2014 of which 148 were included in the systematic review and 23 in a random-effects meta-analysis study. The random-effects meta-analyses showed that underlying disease or condition (odds ratio [OR] = 6.25; 95% confidence interval [CI] = 2.85 to 13.66) generated the highest pooled estimate. ESBL-producing Klebsiella spp. were spread through person-to-person contact and via sources in the environment; we identified both monoclonal and polyclonal presence. Multi-faceted interventions are needed to prevent transmission of ESBL-producing Klebsiella spp.

The changing epidemiology of hospital outbreaks due to ESBL-producing Klebsiella pneumoniae: the CTX-M-15 type consolidation

ABSTRACT 

Klebsiella pneumoniae is responsible for a large number of hospital outbreaks. In the 1990s, there were clonal epidemics, affecting mostly intensive care patients, which carried SHV and TEM enzyme types. With the advent of CTX-M-15 enzymes in the 2000, plasmids encoding multiple extended-spectrum β-lactamase (ESBL) types were described and, frequently, nosocomial outbreaks reported polyclonal dissemination and involved multiple Enterobacteriaceae. Worryingly, the interface between community and hospital is becoming blurred, and there is increasing evidence for the presence of ESBL-producing K. pneumoniae in the community. Furthermore, carbapenem resistance is increasingly reported in ESBL-producing K. pneumoniae strains. Infection control measures and stewardship programs are vital weapons in controlling the pandemic evolution of multidrug-resistant K. pneumoniae.

Bacteriological profile and clinical predictors of ESBL neonatal sepsis

STUDY OBJECTIVE

Bacteriologic profile and risk factors for ESBL sepsis in newborns admitted to a Level III NICU.

METHODS

This was a retrospective observational study that enrolled newborns admitted to NICU with perinatal risk factors or clinical signs of sepsis and positive blood culture from January 2013 to August 2014. Blood cultures were done by BACTEC and ESBL production was evaluated from double-disc synergy method. Maternal, perinatal and neonatal risk factors were recorded from the case records and computerized information base. Mothers received cephalosporins for PPROM but its use was restricted in newborns for both probable and culture-positive sepsis.

RESULTS

Among the infants with sepsis 24% had early-onset sepsis. The incidence of ESBL of early-onset Gram-negative sepsis (EOGNS) was 44.7% (n = 17 of 38) and it was 65% in late-onset Gram-negative sepsis (n = 84 of 129). The predominant ESBL-producing microbe responsible for neonatal sepsis was Klebsiella sp. Among newborns with EOGNS, the risk factors for the production of ESBL were preterm PROM (p = 0.004) and maternal exposure to antibiotics (p = 0.05).

CONCLUSION

ESBL Gram-negative sepsis is a substantial problem in neonatal infections. Maternal exposure to cephalosporins and maternal PPROM are important risk factors for ESBL Gram-negative EOS.

An Outbreak of Heterogeneous Glycopeptide-IntermediateStaphylococcus aureusRelated to a Device Source in an Intensive Care Unit

Objective.

The emergence ofStaphylococcus aureuswith reduced susceptibility to glycopeptides (glycopeptide-intermediateS. aureus[GISA] and heterogeneous GISA [h-GISA]) leads to intensive care unit (ICU) outbreaks that frequently result in ward closure. We investigated the role of hospital hygiene in the transmission and eradication of an h-GISA outbreak.

Design.

The study is a description of an original environmental investigation around a series of 12 cases.

Setting and Patients.

The outbreak occurred in a 20-bed polyvalent/trauma ICU in a 2,800-bed tertiary care university hospital in France.

Interventions.

Specimens were obtained for surveillance and diagnostic cultures from all patients in the unit. Surface sampling was also performed. Geographic cohorting, contact isolation, emphasis on adherence to infection control practices, and environmental cleaning were implemented.

Results.

Twelve patients with h-GISA infection (n= 5) or colonization (n= 7) were identified. The mean interval between admission and h-GISA detection was 23.6 days (range, 10–89 days), with a median of 16.5 days. Environmental investigation identified an unexpected reservoir, namely, SpO2sensors. The outbreak was controlled by a combination of measures, including eradication of this reservoir, avoiding total ward closure.

Conclusions.

Targeted surface sampling helps to secure the environment through active investigation of various reservoirs while maintaining normal activity on the ward. In our study, this method led to the detection of an unsuspected reservoir, the eradication of which helped control the h-GISA epidemic. Further applications of this original investigative procedure should allow confirmation of its relevance and efficiency.

Infect Control Hosp Epidemiol2012;33(2):167-174

Antibiotics and bacterial resistance in the 21st century

Dangerous, antibiotic resistant bacteria have been observed with increasing frequency over the past several decades. In this review the factors that have been linked to this phenomenon are addressed. Profiles of bacterial species that are deemed to be particularly concerning at the present time are illustrated. Factors including economic impact, intrinsic and acquired drug resistance, morbidity and mortality rates, and means of infection are taken into account. Synchronously with the waxing of bacterial resistance there has been waning antibiotic development. The approaches that scientists are employing in the pursuit of new antibacterial agents are briefly described. The standings of established antibiotic classes as well as potentially emerging classes are assessed with an emphasis on molecules that have been clinically approved or are in advanced stages of development. Historical perspectives, mechanisms of action and resistance, spectrum of activity, and preeminent members of each class are discussed.

Clinical relevance of the ESKAPE pathogens

In recent years, the Infectious Diseases Society of America has highlighted a faction of antibiotic-resistant bacteria (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa and Enterobacter spp.) - acronymically dubbed 'the ESKAPE pathogens' - capable of 'escaping' the biocidal action of antibiotics and mutually representing new paradigms in pathogenesis, transmission and resistance. This review aims to consolidate clinically relevant background information on the ESKAPE pathogens and provide a contemporary summary of bacterial resistance, alongside pertinent microbiological considerations necessary to face the mounting threat of antimicrobial resistance.

Outbreak of pan-susceptible Klebsiella pneumoniae in a neonatal intensive care unit

We describe the outbreak of a pan-susceptible Klebsiella pneumoniae strain in a neonatal intensive care unit. A total of 7 neonates developed bacteraemia (37% attack rate), of whom 3 died (43% case fatality rate). A birth weight < 1500 g was the only statistically significant risk factor. Despite an extensive environmental investigation, the source was not identified.

Extended Spectrum Beta-Lactamase-ProducingKlebsiella pneumoniaeOutbreaks During a Third Generation Cephalosporin Restriction Policy

In spite of the adoption of third generation cephalosporin restriction policies, two independent outbreaks by Extended Spectrum Beta-Lactamase (ESBL)-producing Klebsiella pneumoniae occurred in two different wards (Neonatal Intensive Care Unit, NICU and Neurosurgery) of a teaching hospital in Rome, Italy. In the former 19 infected neonates were reported, whereas in the latter there were 10 infected patients. In both wards no differences were observed in the mortality rates in periods of outbreak and those with no outbreak. Molecular typing on a total of 19 isolated strains was carried out and restriction patterns were compared. The PFGE showed that nine isolates responsible for infection in the NICU were all included in three closely related clusters. In Neurosurgery nine strains out of ten were strictly related and part of an outbreak occurring between August-December 2003, while one isolate was temporarily (February 2003) and genetically (seven band differences) unrelated to the outbreak strains. When ESBL producing K. pneumoniae clusters from the two wards (NICU vs Neurosurgery) were compared, they appeared to be completely different both for their genotype pattern and plasmid type or presence, thus demonstrating cross transmission by two different genotypes.

Limits of patient isolation measures to control extended-spectrum beta-lactamase-producing Enterobacteriaceae: model-based analysis of clinical data in a pediatric ward

Background

Extended-spectrum beta-lactamase–producing Enterobacteriaceae (ESBL-E) are a growing concern in hospitals and the community. How to control the nosocomial ESBL-E transmission is a matter of debate. Contact isolation of patients has been recommended but evidence supporting it in non-outbreak settings has been inconclusive.

Methods

We used stochastic transmission models to analyze retrospective observational data from a two-phase intervention in a pediatric ward, successively implementing single-room isolation and patient cohorting in an isolation ward, combined with active ESBL-E screening.

Results

For both periods, model estimates suggested reduced transmission from isolated/cohorted patients. However, most of the incidence originated from sporadic sources (i.e. independent of cross-transmission), unaffected by the isolation measures. When sporadic sources are high, our model predicted that even substantial efforts to prevent transmission from carriers would have limited impact on ESBL-E rates.

Conclusions

Our results provide evidence that, considering the importance of sporadic acquisition, e.g. endogenous selection of resistant strains following antibiotic treatment, contact-isolation measures alone might not suffice to control ESBL-E. They also support the view that estimating cross-transmission extent is key to predicting the relative success of contact-isolation measures. Mathematical models could prove useful for those estimations and guide decisions concerning the most effective control strategy.

Outbreak of ampicillin/piperacillin-resistant Klebsiella pneumoniae in a neonatal intensive care unit (NICU): investigation and control measures

Klebsiella pneumoniae is a frequent cause of infectious outbreaks in Neonatal Intensive Care Units (NICUs). The aim of this paper is to describe an outbreak occurred in a 13-bed NICU and the control measures adopted in order to interrupt the chain of transmission. We described the microbiological investigations, the NICU staff compliance to the infection control measures by means of a specifically designed check-list and the control measures adopted. Six cases of primary bloodstream infections sustained by ampicillin/piperacillin-resistant Klebsiella pneumoniae were observed over a two-month period. One culture obtained from a 12% saccarose multiple-dose solution allowed the growth of Klebsiella pneumoniae. During the inspections performed by the Hospital Infection Control Team, using the check-list for the evaluation of the NICU staff compliance to the infection control measures, several breaches in the infection control policy were identified and control measures were adopted. In our case the definition of a specific check-list led to the adoption of the correct control measures. Further studies would be helpful in order to develop a standard check-list able to identify critical flows in the adhesion to the guidelines. It could be used in different NICUs and allow to obtain reproducible levels of infection control.

Preventing multidrug-resistant gram-negative organisms in surgical patients

Multidrug-resistant gram-positive infections have consumed the attention of health care organizations as well as the media, but recently multidrug-resistant gram-negative organisms (MDR-GNOs) have become more and more prevalent. Limited treatment options are available for MDR-GNO infections; thus, prevention is key. Patients who are at high risk for developing infections must be identified, and specialized prevention interventions must be developed for their care. Surgical patients are one subset of patients at high risk for developing MDR-GNOs. Advanced practice nurses must support nurses and other health care personnel in preventing MDR-GNO infections. Education should include active surveillance, contact precautions, cohorting patients and staff members, unit closures, reinforced hand hygiene practices, and environmental cleaning tailored to the care of surgical patients in regard to their preoperative, intraoperative, and postoperative care.

Quarantine, isolation, and cohorting: from cholera to Klebsiella

BACKGROUND

Isolation is defined as the separation of persons with communicable diseases from those who are healthy. This public health practice, along with quarantine, is used to limit the transmission of infectious diseases and provides the foundation of current-day cohorting.

METHODS

Review of the pertinent English-language literature.

RESULTS

Mass isolation developed during the medieval Black Death outbreaks in order to protect ports from the transmission of epidemics. In the mid-1800s, infectious disease hospitals were opened. It now is clear that isolation and cohorting of patients and staff interrupts the transmission of disease. Over the next century, with the discovery of penicillin and vaccines against many infectious agents, the contagious disease hospitals began to close. Today, we find smaller outbreaks of microorganisms that have acquired substantial resistance to antimicrobial agents. In the resource-limited hospital, a dedicated area or region of a unit may suffice to separate affected from unaffected patients.

CONCLUSION

Quarantine, or cohorting when patients are infected with the same pathogen, interrupts the spread of infections, just as the contagious disease hospitals did during the epidemics of the 18th and 19th centuries.

Extended spectrum ß-lactamase-producing Escherichia coli in neonatal care unit

An outbreak of extended-spectrum β-lactamase–producing Escherichia coli in a neonatal care unit began with transmission from a mother to her newborn twins during vaginal delivery. Subsequently, infection spread by healthcare worker contact with other neonates; a healthcare worker also was infected. Knowledge about transmission may improve infection control measures.

[Description and investigation of an outbreak of extended-spectrum beta-lactamase producing Escherichia coli strain in a neonatal unit]

An outbreak of colonization and infection with an Escherichia coli strain producing extended-spectrum beta-lactamase (ESBL) occurred in a neonatal unit : a high rate of cases was observed, 27/59 neonates were colonized : one of them developed meningitis with favourable outcome and another baby developed conjunctivitis. Despite intensive efforts to control the outbreak by standard methods of hand hygiene, patients screening and isolation, the spread was uncontrolled and the unit was closed to all admission in order to stop the outbreak. The investigation was not able to identify a single outbreak's source. Emergence and spread of ESBL producing E. coli strains from community and hospital acquired infections are a significant public health problem with difficult choice of treatment for serious infections.

Meningitis caused by Escherichia coli producing TEM-52 extended-spectrum beta-lactamase within an extensive outbreak in a neonatal ward: epidemiological investigation and characterization of the strain

Outbreaks caused by Enterobacteriaceae isolates producing extended-spectrum beta-lactamases (ESBL) in neonatal wards can be difficult to control. We report here an extensive outbreak in a neonatal ward with a case of meningitis caused by an ESBL-producing Escherichia coli strain. Between 24 March and 29 April 2009, among the 59 neonates present in the ward, 26 neonates with ESBL-producing E. coli rectal colonization were detected (44%). One of the colonized neonates developed meningitis with a favorable outcome after treatment combining imipenem, gentamicin, and ciprofloxacin. Despite strict intensification of hygiene and isolation procedures for more than 1 month, ward closure to new admissions was necessary to control the outbreak. Randomly amplified polymorphic DNA and pulsed-field gel electrophoresis analysis performed on 31 isolates recovered from 26 neonates and two mother's milk samples showed a clonal strain. ESBL PCR assays indicated that the strain harbored a TEM-52 ESBL encoded by an IncI1 replicon. Phylogenetic analysis by multilocus sequence typing showed that the strain belonged to rare phylogenetic group C, which is closely related to group B1 but appears as group A by the triplex PCR phylogrouping method. The strain harbored the virulence genes fuyA, aer, and iroN and was virulent in a mouse model of septicemia. This work indicates the high potential of colonization, transmission, and virulence of some ESBL-producing E. coli clones.

Eradication of an extensive outbreak in a neonatal unit caused by two sequential Klebsiella pneumoniae clones harbouring related plasmids encoding an extended-spectrum beta-lactamase

Outbreaks caused by extended-spectrum beta-lactamase (ESBL)-producing Klebsiella pneumoniae are difficult to control and closure of an affected unit is sometimes necessary. We describe an outbreak of ESBL-producing K. pneumoniae in a 28-bed neonatal unit that began in August 2005 and lasted for seven months. Weekly rectal swabs were taken from all babies admitted throughout the study period. Review of all procedures, contact precautions, thorough environmental cleaning and restriction of cephalosporin use were implemented. ESBL production was investigated according to CLSI recommendations, and characterised by isoelectric focusing and sequencing. Typing of isolates was assessed by pulsed-field gel electrophoresis. Plasmids were also studied. During the outbreak, 32% of 503 admitted babies became colonised and nine babies developed bacteraemia; all the babies recovered. The outbreak was finally terminated in February 2006. Two distinct clones were observed, the first circulating between August and October 2005, and the second between October 2005 and February 2006. Both of these clones carried the non-ESBL SHV-11 and TEM-4 ESBL. Plasmids harbouring TEM-4 from both clones were similar and molecular analysis suggested horizontal dissemination of a single plasmid between the two clones.

How clean is clean? Proposed methods for hospital cleaning assessment

SUMMARY

Reducing infection rates in hospitals depends on a variety of factors, including environmental measures. Although microbiological standards have been proposed for surface hygiene in hospitals, standard methods for environmental sampling have not been discussed. The aim of this study was to assess the effectiveness of cleaning/disinfection in critical care units using the wipe-rinse method to detect an indicator organism and dipslides to quantitatively determine the microbial load. Frequent-hand-touch surfaces from clinical and non-clinical areas were microbiologically surveyed, targeting both meticillin-susceptible (MSSA) and meticillin-resistant (MRSA) Staphylococcus aureus. A subset of the surfaces targeted was sampled quantitatively to determine the total aerobic count. MRSA was isolated from 9 (6.9%) and MSSA was isolated from 15 (11.5%) of the 130 samples collected. Seven of 81 (8.6%) samples collected from non-clinical areas grew MRSA, compared with two (4.1%) from 49 samples collected from clinical areas. Of 116 sites screened for the total aerobic count, 9 (7.7%) showed >5 cfu/cm(2) microbial growth. Bed frames, telephones and computer keyboards were among the surfaces that yielded a high total viable count. There was no direct correlation between the findings of total aerobic count and MRSA isolation. We suggest, however, that combining both standards will give a more effective method of assessing the efficacy of cleaning/disinfection strategy. Further work is required to evaluate and refine these standards in order to assess the frequency of cleaning required for a particular area, or for changing the protocol or materials used.

Intensive care unit outbreak of extended-spectrum beta-lactamase-producing Klebsiella pneumoniae controlled by cohorting patients and reinforcing infection control measures

OBJECTIVE

To describe an outbreak of extended-spectrum beta-lactamase (ESBL)-producing Klebsiella pneumoniae in the intensive care units (ICUs) of a hospital and the impact of routine and reinforced infection control measures on interrupting nosocomial transmission.

DESIGN

Outbreak report.

SETTING

A 31-bed intensive care department (composed of 4 ICUs) in a university hospital in Belgium.

INTERVENTION

After routine infection control measures (based on biweekly surveillance cultures and contact precautions) failed to interrupt a 2-month outbreak of ESBL-producing K. pneumoniae, reinforced infection control measures were implemented. The frequency of surveillance cultures was increased to daily sampling. Colonized patients were moved to a dedicated 6-bed ICU, where they received cohorted care with the support of additional nurses. Two beds were closed to new admissions in the intensive care department. Meetings between the ICU and infection control teams were held every day. Postdischarge disinfection of rooms was enforced. Broad-spectrum antibiotic use was discouraged.

RESULTS

Compared with a baseline rate of 0.44 cases per 1,000 patient-days for nosocomial transmission, the incidence peaked at 11.57 cases per 1,000 patient-days (October and November 2005; rate ratio for peak vs baseline, 25.46). The outbreak involved 30 patients, of whom 9 developed an infection. Bacterial genotyping disclosed that the outbreak was polyclonal, with 1 predominant genotype. Reinforced infection control measures lasted for 50 days. After the implementation of these measures, the incidence fell to 0.08 cases per 1,000 patient-days (rate ratio for after the outbreak vs during the outbreak, 0.11).

CONCLUSION

These data indicate that, in an intensive care department in which routine screening and contact precautions failed to prevent and interrupt an outbreak of ESBL-producing K. pneumoniae, reinforced infection control measures controlled the outbreak without major disruption of medical care.

Extended-spectrum beta-lactamase-producing Klebsiella spp. in a neonatal intensive care unit: risk factors for the infection and the dynamics of the molecular epidemiology

The extended-spectrum beta-lactamase (ESBL)-producing Klebsiella spp. cause worldwide problems in intensive care units. The aim of this study was to investigate the molecular epidemiology of ESBL-producing Klebsiella pneumoniae and K. oxytoca strains in a neonatal intensive care unit (NICU) in Budapest, Hungary and to determine the risk factors of the infections and the epidemiological features. Infections with Klebsiella spp. were analyzed retrospectively by reviewing the medical records between January 2001 and December 2005. Antibiotic susceptibility tests, isoelectric focusing, pulsed field gel electrophoresis, plasmid analysis, PCR for bla(TEM) and bla(SHV) and DNA sequencing analysis were performed on ESBL-producing Klebsiella isolates. A total of 45 babies were found to be infected with non-ESBL-producing Klebsiella spp. and 39 with ESBL-producing Klebsiella spp. Of the parameters analyzed, including sex, gestational age, twin pregnancy, birth weight, presence of central vascular catheter, mechanical ventilator use, parenteral nutrition, polymicrobial infection, caesarean section, transfusion and mortality, we found no statistically significant difference between the ESBL and the non-ESBL groups, or between the K. pneumoniae and K. oxytoca species. Further characterization of the ESBL-producing K. pneumoniae and K. oxytoca strains isolated between February 2001 and January 2003 revealed three distinct PFGE patterns of SHV-5-producing K. pneumoniae (A, B, E) and two distinct patterns of SHV-12-producing K. oxytoca (C,D) isolates; these had different plasmid profiles. From July to November 2005, a new SHV-5 producing K. oxytoca (F) was isolated. The molecular epidemiology of ESBL-producing organisms in a NICU over time shows substantial shifts in predominant strains. The ESBL production of the infected organisms has an impact on the survival of newborn babies with infections caused by Klebsiella spp.

Closure of medical departments during nosocomial outbreaks: data from a systematic analysis of the literature

A total closure of an affected medical department is one of the most expensive infection control measures during investigation of a nosocomial outbreak. However, until now there has been no systematic analysis of typical characteristics of outbreaks, for which closure was considered necessary. This article presents data on features of such nosocomial epidemics published during the past 40 years in the medical literature. A search of the Outbreak Database (1561 nosocomial outbreaks in file) revealed a total of 194 outbreaks that ended up with some kind of closure of the unit (median closure time: 14 days). Closure rates (CRs) were calculated and stratified for medical departments, for causative pathogens, for outbreak sources, and for the assumed mode of transmission. Data were then compared to the overall average CR of 12.4% in the entire database. Wards in geriatric patient care were closed significantly more frequently (CR: 30.3%; P < 0.001) whereas paediatric wards showed a significantly lower CR (6.1%; P = 0.03). Pathogen species with the highest CR were norovirus (44.1%; P < 0.001) and influenza/parainfluenza virus (38.5%; P < 0.001). If patients were the source of the outbreak, the CR was significantly increased (16.7%; P = 0.03). Infections of the central nervous system were most often associated with closure of the ward (24.2%; P = 001). A systematic evaluation of nosocomial outbreaks can be a valuable tool for education of staff in the absence of an outbreak, but may be even more helpful for potentially cost-intensive decisions in the acute outbreak setting on the ward.

Prevention of catheter-related bloodstream infections in the neonatal intensive care setting

Nosocomial infection causes substantial morbidity and mortality among neonates treated in the neonatal intensive care setting. Colonization and subsequent infection of central venous catheters leading to catheter-related bloodstream infection is among the most common causes of nosocomial sepsis in this patient population. Prevention of catheter-related bloodstream infection is a major challenge and numerous strategies have been attempted in this context with varying success. Given the dynamic epidemiology of nosocomial infection among neonates and the emergence of antimicrobial resistance, novel prevention strategies are urgently required.

An outbreak of Serratia marcescens on the neonatal unit: a tale of two clones

Serratia spp. are an important cause of hospital-acquired infections and outbreaks in high-risk settings. Twenty-one patients were infected or colonized over a nine-month period during 2001-2002 on a neonatal unit. Twenty-two isolates collected were examined for antibiotic susceptibility, beta-lactamase production and genotype. Random-amplified polymorphic DNA polymerase chain reaction and pulsed-field gel electrophoresis revealed that two clones were present. The first clone caused invasive clinical infection in four babies, and was subsequently replaced by a non-invasive clone that affected 14 babies. Phenotypically, the two strains also differed in their prodigiosin production; the first strain was non-pigmented whereas the second strain displayed pink-red pigmentation. Clinical features suggested a difference in their pathogenicity. No environmental source was found. The outbreak terminated following enhanced compliance with infection control measures and a change of antibiotic policy. Although S. marcescens continued to be isolated occasionally for another five months of follow-up, these were sporadic isolates with distinct molecular typing patterns.