Analysis of two sequential SARS-CoV-2 outbreaks on a haematology-oncology ward and the role of infection prevention.

Two SARS-CoV-2 nosocomial outbreaks occurred on the haematology ward of our hospital. Patients on the ward were at high risk for severe infection because of their immunocompromised status. Whole Genome Sequencing proved transmission of a particular SARS-CoV-2 variant in each outbreak. The first outbreak (20 patients/31 healthcare workers (HCW)) occurred in November 2020 and was caused by a variant belonging to lineage B.1.221. At that time, there were still uncertainties on mode of transmission of SARS-CoV-2, and vaccines nor therapy were available. Despite HCW wearing II-R masks in all patient contacts and FFP-2 masks during aerosol generating procedures (AGP), the outbreak continued. Therefore, extra measures were introduced. Firstly, regular PCR-screening of asymptomatic patients and HCW; positive patients were isolated and positive HCW were excluded from work as a rule and they were only allowed to resume their work if a follow-up PCR CT-value was ≥30 and were asymptomatic or having only mild symptoms. Secondly, the use of FFP-2 masks was expanded to some long-lasting, close-contact, non-AGPs. After implementing these measures, the incidence of new cases declined gradually. Thirty-seven percent of patients died due to COVID-19. The second outbreak (10 patients/2 HCW) was caused by the highly transmissible omicron BA.1 variant and occurred in February 2022, where transmission occurred on shared rooms despite the extra infection control measures. It was controlled much faster, and the clinical impact was low as the majority of patients was vaccinated; no patients died and symptoms were relatively mild in both patients and HCW.

Role of the environment in transmission of Gram-negative bacteria in two consecutive outbreaks in a haematology-oncology department.

In 2019-2020, two subsequent outbreaks caused by phenotypically identical ESBL-producing Enterobacter cloacae and multi-drug-resistant (MDR) Pseudomonas putida were detected in respectively 15 and 9 patients of the haematology-oncology department. Both bacterial species were resistant to piperacillin-tazobactam, used empirically in (neutropenic) sepsis in our hospital, and ciprofloxacin, used prophylactically in selective digestive decontamination for haematology patients. The E. cloacae outbreak was identified in clinical cultures of blood and urine. Despite intensified infection control measures, new cases were found in weekly point-prevalence screening cultures. Environmental samples of sinks and shower drains appeared positive in 18.1%. To diminish the environmental contamination burden, all siphons of sinks were replaced, and disinfection of sinks and shower drains was intensified using chlorine and soda on a daily basis. Replacement of shower drains was not possible. The outbreak of P. putida remained limited to rectal cultures only, and disappeared spontaneously without interventions. During both outbreaks, multiple strains of the incriminated bacterium were found simultaneously (demonstrated by Amplified-Fragment Length Polymorphism and/or Whole-Genome Multi-locus Sequencing Typing) in patients as well as the environment. It was experimentally shown that a biofilm on the toilet edge may act as a source for nosocomial transmission of Gram-negative bacteria. In conclusion, the drainage system of the hospital is an important reservoir of MDR bacteria, threatening the admitted patients. In existing hospitals, biofilms in the drainage systems cannot be removed. Therefore, it is important that in (re)building plans for hospitals a plan for prevention of nosocomial transmission from environment to patients is incorporated.

The sink as a correctable source of extended-spectrum ß-lactamase contamination for patients in the intensive care unit.

Between December 2010 and April 2012, intensive care unit (ICU) patients in our hospital were infrequently colonized with extended-spectrum ß-lactamase-positive bacteria (ESBLs). We hypothesized that these ESBLs originated from patients' room sinks, and this was prospectively investigated by weekly culturing of patients and sinks during a 20-week period. ESBLs were isolated from all 13 sinks. Four patients became colonized with ESBLs that were genetically identical to ESBLs that had previously been isolated from the sink. One of these patients died of pneumonia caused by the ESBL. Transmission from sinks to patients was stopped by integrating self-disinfecting siphons to all sinks on the ICU.

A randomised trial of honey barrier cream versus zinc oxide ointment.

In this single-blind multicentre, intervention study, 31 patients with symmetrical intertrigo in large skin folds were included to study the clinical effect of two topical treatments, i.e. standard therapy with zinc oxide ointment versus honey barrier cream. Patients were treated twice daily for 21 days, and the severity of intertrigo was scored in an observation period of 21 days. Patients were used as their own controls by treating symmetrical skin folds, on the left and right side. There was no significant difference in treatment effect between intervention groups. For the majority of patients, both treatments were effective. However, the use of honey barrier cream showed lower pruritus complaints (12.9% versus 29.0%). Honey barrier cream is a suitable alternative in the treatment of intertrigo, and promotes patient comfort.

Application of the forensic Luminol for blood in infection control.

Transmission of hepatitis C virus occurs frequently in haemodialysis units. A possible route of transmission is indirectly via the hospital environment although this has never been recorded. We investigated the haemodialysis unit in Deventer Hospital, Deventer, The Netherlands, with the forensic Luminol test. With this test, invisible traces of blood can be visualised based on the principle of biochemiluminescence. We demonstrated extensive contamination of the environment with traces of blood. The aim of this article is to introduce this method to infection control professionals, so it can be used to monitor cleaning and disinfection procedures, and alert healthcare workers to the possibility of contamination of the hospital environment with blood.

Mannose-binding lectin (MBL) genotype in relation to risk of nosocomial infection in pre-term neonates in the neonatal intensive care unit.

Mannose-binding lectin (MBL) plays an important role in the innate immune response. Three alleles in the MBL gene, and one allele of the promoter, independently cause low serum MBL levels as compared with the wild-type. This study investigated the relationship between MBL genotype and the occurrence of nosocomial infection among neonates in a neonatal intensive care unit (NICU). Prospectively gathered information concerning nosocomial infection was available for 742 neonates from a recently performed surveillance study in an NICU. DNA was isolated from Guthriecards for a subgroup of 204 neonates who stayed in the NICU for > or =4 days. After a pre-PCR for the MBL gene in blood spots on Guthriecards, mutations were analysed by real-time PCR to detect six mutations in the MBL gene. An MBL genotype could be determined for 186 neonates. As compared to term neonates, genotypes encoding MBL-deficient haplotypes were significantly more prevalent among pre-term neonates. Forty-one of these neonates developed sepsis, with blood cultures yielding coagulase-negative staphylococci in 25 cases. Pneumonia occurred in 30 cases, with various causative organisms. No relationship was found between MBL genotype and the risk of nosocomial sepsis or pneumonia, even after correction for birth-weight, perhaps because of an insufficient correlation between genotype and the concentration of functional MBL. In addition, most bloodstream infections in the NICU were caused by coagulase-negative staphylococci, to which MBL binds poorly.

Treatment of grade 2 and 3 hemorrhoids with Doppler-guided hemorrhoidal artery ligation.

AIM: We evaluated the results of the Doppler-guided hemorrhoidal arterial ligation (DG-HAL) method in the management of symptomatic grade 2 and 3 hemorrhoids. PATIENTS AND METHODS: Between June 2005 and March 2006, 110 consecutive patients with symptomatic grade 2 and 3 hemorrhoids according to the DG-HAL method were treated. All procedures were performed in daycare under spinal anesthesia. The primary objective was the reduction in hemorrhoidal gradation as determined by proctoscopy; the secondary was patient satisfaction. This was measured by interviewing patients over the telephone. RESULTS: The average age was 47.6 years. 42 patients had grade 2 hemorrhoids, 68 grade 3. An average of 7.3 ligations were placed. Proctoscopy showed that, after 6 weeks, 97 (88%) patients had a significant improvement in their hemorrhoidal gradation. After an average follow-up of 37 weeks, 93 of the 110 (84.5%) patients were satisfied with the postoperative result. Mortality was 0% and morbidity 3%. CONCLUSION: DG-HAL is a safe and effective treatment in the management of symptomatic grade 2 and 3 hemorrhoids.

Rectal carcinoma treated with short-term preoperative radiotherapy followed by abdominoperineal resection. Significantly more presacral abscesses with absence of local recurrence.

BACKGROUND: Treatment of choice for rectal carcinoma is short-term preoperative radiotherapy (5 x 5 Gy) followed by a total mesorectal excision (TME) of the rectum. This treatment has led to a reduction in local recurrence 2 years after surgery from 8.2 to 2.4%. Side effects of this treatment seem to be marginal and of no consequence. After introduction of short-term preoperative radiotherapy we noticed a rise in the postoperative presacral abscess formation which is difficult to treat and results in readmissions and prolonged hospital stay. Research was needed to investigate whether short-term preoperative radiotherapy can be held accountable for the presumed rise in presacral abscess formation in the treatment of rectal carcinoma. METHODS: A retrospective study was performed over the period January 2000-October 2004. Two groups were formed. Group 1 existed of 30 patients who underwent a TME of the rectum without short-term preoperative radiotherapy. Group two existed of 35 patients who underwent a TME of the rectum with short-term preoperative radiotherapy. RESULTS: Statistical analysis showed a significant increase in presacral abscess formation (13 vs. 40%) after introduction of short-term preoperative radiotherapy. Radiotherapy proved to be an important risk factor. Reduction in incidence of local recurrence was not evident. CONCLUSION: We found a significant increase in presacral abscess formation strongly suggestive due to the introduction of short-term preoperative radiotherapy in the treatment of rectal carcinoma. We noticed no reduction in incidence of local recurrence. We advocate that additional research is needed in order to formulate extra patient selection criteria for the use of preoperative radiotherapy in the treatment of rectal cancer.

[Outbreak of multi-resistant Escherichia coli on a surgical ward: course, measures and consequences for future admissions of contaminated patients]. / Multiresistente Escherichia coli-epidemie op een chirurgische afdeling: verloop, maatregelen en consequenties voor toekomstige opnamen van besmette patiënten.

In the period July-September 2003, a multi-resistant Escherichia coli strain caused an outbreak on a surgical ward in the Deventer Hospital, the Netherlands. This strain produced a beta-lactamase with an extended spectrum, making it resistant to third generation cephalosporins. Furthermore, the strain was resistant to trimethoprim-sulphamethoxazole (co-trimoxazole), gentamicin and quinolones, so that only treatment with carbapenems was possible. 8 patients were colonised. Genotyping of the strains by means of amplified fragment length polymorphism indicated the spread of a single strain. A multidisciplinary crisis team coordinated the infection control measures and the communication to involved persons and the press. Control measures consisted of contact isolation of colonised patients and extra attention to hand hygiene. After this proved to be ineffective, all patients on the ward were screened and the ward was closed for several days. The outbreak was stopped by strict cohorting ofthe colonised patients. There were no indications for transmission of resistance genes by plasmids. Several months later, on visiting the outpatient clinic, 3 other patients appeared to have been colonised by the epidemic E. coli strain during their admission. They had not been screened because they had already been discharged when all patients on the ward were screened for colonisation. In a follow-up study 9 months after the outbreak, 3 of the 6 investigated patients, who had in the meantime returned home, were still found to be colonised. Such patients constitute a risk for the re-introduction of multi-resistant bacteria into the hospital and should be preventively screened and isolated on admission.

Nosocomial infections in a Dutch neonatal intensive care unit: surveillance study with definitions for infection specifically adapted for neonates.

The incidence of nosocomial infection in neonatal intensive care units (NICUs) is high compared with other wards. However, no definitions for hospital-acquired infection are available for NICUs. The aim of this study was to measure the incidence of such infections and to identify risk factors in the NICU of the VU University Medical Center, which serves as a level III regional NICU. For this purpose, a prospective surveillance was performed in 1998-2000. We designed definitions by adjusting the current definitions of the Centers for Disease Control and Prevention (CDC) for children <1 year of age. Birth weight was stratified into four categories and other baseline risk factors were dichotomized. Analysis of risk factors was performed by Cox regression with time-dependent variables. The relationship between the Clinical Risk Index for Babies (CRIB) and nosocomial infection was investigated. Furthermore, for a random sample of cases, we determined whether bloodstream infection and pneumonia would also have been identified with the CDC definitions. Seven hundred and forty-two neonates were included in the study. One hundred and ninety-one neonates developed 264 infections. Bloodstream infection (N=138, 14.9/1000 patient-days) and pneumonia (N=69, 7.5/1000 patient-days) were the most common infections. Of bloodstream infections, 59% were caused by coagulase-negative staphylococci; in 21% of neonates, blood cultures remained negative. In 25% of pneumonias, Enterobacteriaceae were the causative micro-organisms; 26% of cultures remained negative. Compared with the Nosocomial Infections Surveillance System (NNIS) of the CDC, our device utilization ratios and device-associated nosocomial infection rates were high. The main risk factors for bloodstream infection were birth weight [hazard ratio (HR) 1.79, 95% confidence interval (CI) 1.45-2.17] and parenteral feeding with hospital-pharmacy-produced, all-in-one mixture 'Minimix' (HR 3.69, 95%CI 2.03-6.69); administration of intravenous antibiotics (HR 0.39, 95%CI 0.26-0.56) was a protective risk factor. The main risk factors for pneumonia were low birth weight (HR 1.37, 95%CI 1.01-1.85) and mechanical ventilation (HR 9.69, 95%CI 4.60-20.4); intravenous antibiotics were protective (HR 0.37, 95%CI 0.21-0.64). In a subcohort of 232 very-low-birthweight neonates, the CRIB was not predictive for infection. With the CDC criteria, only 75% (21/28) of bloodstream infections and 87.5% of pneumonias (21/24) would have been identified. In conclusion, our local nosocomial infection rates are high compared with those of NICUs participating in the NNIS. This can be partially explained by: (1) the use of our definitions for nosocomial infection, which are more suitable for this patient category; and (2) the high device utilization ratios.

[Enterobacter cloacae epidemic on a neonatal intensive care unit due to the use of contaminated thermometers]. / Enterobacter cloacae-epidemie op een neonatale intensive-care-unit door gebruik van besmette thermometers.

From December 1999 to March 2000 a nosocomial outbreak of multiresistant Enterobacter cloacae occurred in the neonatal intensive care unit (NICU) at the VU Medical Center, Amsterdam, the Netherlands. Twenty-six patients were infected or colonized with this strain resistant to third generation cephalosporins and with decreased sensitivity for aminoglycosides. Three neonates experienced sepsis with E. cloacae with serious clinical symptoms and two of them died. Comparison of the Enterobacter isolates by amplified-fragment length polymorphism indicated that this outbreak was caused by the spread of a single strain. Infection control precautions were initiated in order to stop further spread; barrier precautions, enforcement of hand disinfection and cohorting of colonized patients. A multidisciplinary crisis team coordinated these infection control precautions and informed all persons involved. Analysis of antibiotic usage in 1999 showed an increase in the use of third generation cephalosporins from November onwards. Due to the resistance pattern of the epidemic strain the use of third generation cephalosporins was discontinued in February 2000. At the end of February the NICU was temporarily closed. The epidemic strain of E. cloacae was isolated from one digital rectal thermometer. Patient use of thermometers and disposable coverings for rectal thermometers were introduced to eliminate this possible means of spread. No spread of multiresistant E. cloacae was found following the introduction of these interventions. Once all the neonates had been transferred, the NICU was disinfected and reopened in March.

Outbreak of Bacillus cereus infections in a neonatal intensive care unit traced to balloons used in manual ventilation.

In 1998, an outbreak of systemic infections caused by Bacillus cereus occurred in the Neonatal Intensive Care Unit of the University Hospital Vrije Universiteit, Amsterdam, The Netherlands. Three neonates developed sepsis with positive blood cultures. One neonate died, and the other two neonates recovered. An environmental survey, a prospective surveillance study of neonates, and a case control study were performed, in combination with molecular typing, in order to identify potential sources and transmission routes of infection. Genotypic fingerprinting by amplified-fragment length polymorphism (AFLP) showed that the three infections were caused by a single clonal type of B. cereus. The same strain was found in trachea aspirate specimens of 35 other neonates. The case control study showed mechanical ventilation with a Sensormedics ventilation machine to be a risk factor for colonization and/or infection (odds ratio, 9.8; 95% confidence interval, 1.1 to 88.2). Prospective surveillance showed that colonization with B. cereus occurred exclusively in the respiratory tract of mechanically ventilated neonates. The epidemic strain of B. cereus was found on the hands of nursing staff and in balloons used for manual ventilation. Sterilization of these balloons ended the outbreak. We conclude that B. cereus can cause outbreaks of severe opportunistic infection in neonates. Typing by AFLP proved very useful in the identification of the outbreak and in the analysis of strains recovered from the environment to trace the cause of the epidemic.

Nosocomial outbreak of gentamicin-resistant Klebsiella pneumoniae in a neonatal intensive care unit controlled by a change in antibiotic policy.

Between August and November 1997, a nosocomial outbreak caused by gentamicin-resistant Klebsiella pneumoniae occurred in the Neonatal Intensive Care Unit (NICU) of our hospital. Thirteen neonates became colonized and three of them became infected. Comparison of the isolates by amplified fragment length polymorphism (AFLP) revealed clonal similarity for isolates of eight neonates (homology > 90%). Cultures from environmental specimens were negative for gentamicin-resistant K. pneumoniae. A case-control study was conducted to identify risk factors associated with acquisition of gentamicin-resistant K. pneumoniae. Risk factors were low gestational age and birth weight. These neonates need more care and handling and may therefore, be more at risk of colonization. Length of stay on the NICU was significantly longer for cases, but mean time until colonization (6.3 days) was shorter than the total stay for controls (9.5 days). No single member of the medical or nursing staff was significantly more involved with cases than with controls. The outbreak was stopped by replacing gentamicin by amikacin as the antibiotic of first choice whenever the use of an aminoglycoside antibiotic was indicated.

Duplex (thermotroph-psychrotroph) quadrant plates: convenient, error-avoiding tools for monitoring of HACCP-contained food lines and for epidemiological investigations under conditions of military or other constraints.

A set of two "two-tier" (thermotroph-psychrotroph) single quadrant plates (QPs) was developed previously to allow convenient enumeration of numbers of colony-forming units of most pertinent pathogenic bacteria or marker bacteria in foods. These include Listeria monocytogenes, Staphylococcus aureus, Bacillus cereus, thermotrophic and psychrotrophic Enterobacteriaceae, Clostridium spp., and Enterococcus spp. As the QPs had given excellent results in monitoring samples of marketed food products potentially involved in food-transmitted illnesses, the approach was tested for practicability under military deployment and other constraints. Three approaches were envisaged: (i) validating lapse-free adherence to meticulously codified good military catering practices; (ii) acceptance/rejection testing of locally procured foods or meals; and (iii) employing rapid culture in support of evidence obtained by microscopy in attempts to identify foods involved in infectious or toxic disease outbreaks occurring in the field. The method was found to be elegant, avoiding confusion when larger number of specimens were to be screened, as well as easy to teach to staff with little or no training in microbiology, and it provided entirely reliable results. For use outside the laboratory, preparation of food macerates by use of shake flasks containing glass or plastic beads and peptone saline as a substitute for stomaching was found acceptable, though the shake flask technique led to slightly diminished colony counts. Results obtained with incubation times shortened to ca. 12 h could be relied on only when the results were alarmingly positive, but not when the colony counts at the 12-h point did not yet indicate a reason for concern.