Environmental Drivers of Bacillus-Positive Blood Cultures in a Cancer Hospital, Sapporo, Japan.

The Bacillus species is a well-documented causative pathogen of nosocomial bloodstream infection. The present study aimed to identify climatological variables that are associated with Bacillus-positive blood culture in Sapporo, Japan. All cases with Bacillus-positive blood cultures from January 2011 to December 2016 were retrospectively analysed. Climatological data from 2011 to 2016, including daily mean temperature and absolute humidity, were retrieved from the Japan Meteorological Agency. Employing a hazard-based statistical model to describe the non-homogeneous counting process in which temperature and absolute humidity act as explanatory variables, we computed all possible models with variable lengths of time lag. Akaike Information Criterion was computed to identify the best fitted model. High wavelet power at 12 months was identified for the period from 2013 onwards, which coincided with the time period in which sampling multiple sets of blood culture has been recommended. The temperature-only model with a lag of six days yielded a high sensitivity value (72.1%) and appeared to be the optimal model to predict Bacillus-positive blood culture with the highest area under the receiver operating characteristic curve value. Temperature was identified as a climatological driver of Bacillus-positive blood culture. Our statistical modelling exercise offers an important message for infection control practices to improve awareness among healthcare workers of the identified association and mechanically controlled in-room temperature.

Seasonal Outbreak of Bacillus Bacteremia Associated With Contaminated Linen in Hong Kong.

BACKGROUND: A high seasonal incidence of Bacillus bacteremia was associated with the use of contaminated hospital linens. METHODS: An outbreak investigation was conducted to study the incidence and source of Bacillus bacteremia during the baseline, outbreak, and postoutbreak period from 1 January 2012 through 31 July 2016 at a university-affiliated teaching hospital in Hong Kong. Replicate organism detection and counting plates were used for microbial screening of linen samples. The Bacillus species isolated from patient and linen samples were identified by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and were phylogenetically analyzed. RESULTS: During the study period, a total of 113 207 blood cultures were collected from 43 271 patients, of which 978 (0.86%) specimens from 744 (1.72%) patients were identified as Bacillus species. The incidence of Bacillus bacteremia per 10 000 patient admissions and per 10 000 patient-days was significantly higher during the summer outbreak as compared with baseline and 1 year postoutbreak after cessation of the linen supply from the designated laundry and change of laundry protocol (39.97 vs 18.21 vs 2.27; 13.36 vs 5.61 vs 0.73; P < .001). The mean total aerobic bacterial count per 100 cm2 was significantly higher among the 99 linen samples screened during the outbreak period compared to the 100 screened in the postoutbreak period (916.0 ± 641.6 vs 0.6 ± 1.6; P < .001). Blood culture isolates of Bacillus cereus group in 14 of 87 (16.1%) patients were phylogenetically associated with 9 linen sample isolates. CONCLUSIONS: Suboptimal conditions of hospital laundry contributed to the seasonal outbreak of Bacillus bacteremia.

Possible contamination of organ preservation fluid with Bacillus cereus: the United Kingdom response.

We describe here the United Kingdom (UK) response following the recent international recall of an organ preservation fluid owing to potential Bacillus cereus contamination. This fluid is used for the transport of solid organs and pancreatic islet cells for transplant. We detail the response mechanisms, including the initial risk stratification, investigatory approaches, isolate analysis and communications to professional bodies. This report further lays out the potential need for enhanced surveillance in UK transplant patients.

Bacillus cereus from blood cultures: virulence genes, antimicrobial susceptibility and risk factors for blood stream infection.

We characterized the profiles of virulence genes and antimicrobial susceptibility of Bacillus cereus isolates from blood cultures as well as the risk factors for blood stream infections (BSIs). The diversity of virulence gene patterns was found to be wide among 15 B. cereus isolates from BSIs and also among 11 isolates from contaminated blood cultures. The MicroScan broth microdilution method yielded results corresponding with those of the agar dilution (reference) method for levofloxacin, linezolid, and vancomycin, while the Etest results were consistent with the reference results for clindamycin, gentamicin, imipenem, levofloxacin, and linezolid. Compared with the reference values, however, some isolates showed marked differences of the minimum inhibitory concentrations (MICs) for ampicillin and clindamycin when determined using the MicroScan method, or the MICs for ampicillin, meropenem, and vancomycin when determined using the Etest method. Significantly more patients were treated with antimicrobials for more than 3 days during the 3-month period before isolation in the BSI group. Prior antimicrobial therapy may be a risk factor for BSIs due to B. cereus.

Food poisoning associated with emetic-type of Bacillus cereus in Korea.

Bacillus cereus can cause diarrheal and emetic types of food poisoning but little study has been done on emetic type of food poisoning in Korea. The objective of this study was to report on the emetic type of food poisoning associated with B. cereus in Korea. The toxin gene profile, toxin production, and antibiotic resistance of B. cereus isolates were investigated in this study. B. cereus was detected in three out of four samples, while the other food poisoning bacteria were not detected. All isolates (KUGH 10, 11, and 12) presented nhe A, B, and C diarrheal toxin genes (755, 743, and 683 bp), detected using NHA, NHB, and NHC primers, and ces emetic toxin gene (1271 bp), detected using CES primer, and produced nonhemolytic enterotoxin and emetic toxin (cereulide), detected using immunochemical assay and high performance liquid chromotography/mass spectrometry (HPLC/MS) analysis. All emetic-associated isolates were resistant to beta-lactam antibiotics. Most important finding in this study was that the risk of emetic-type B. cereus food poisoning has existed in Korea. This suggested that the food poisoning caused by B. cereus producing emetic and diarrheal toxins should be constantly evaluated to prevent misdiagnosis between emetic and diarrheal types of food poisoning.

Bacillus species sepsis in the neonatal intensive care unit.

OBJECTIVES: In 2002 there was an increase in the incidence of Bacillus species sepsis in our NICU that was almost completely resolved in 2003-2004 after the NICU was relocated. Our aims were to identify the source, the risk factors, and to characterize the clinical features of these infections. METHODS: The epidemiological investigation commenced during the outbreak and thereafter. The patient's data were collected retrospectively and a case control study was used to analyze the risk factors. RESULTS: There were eight cases of Bacillus species sepsis: five during 2002, two in 2003, and one in 2004. All infants recovered and salvaging percutaneous central venous catheter (PCVC) was successful in 4/6 of the cases. A case control study identified necrotizing enterocolitis (NEC) and PCVC as risk factors in univariate analysis but only NEC in multivariate analysis. No focal source of Bacillus bacteria was identified, but a high load of bacteria was found in the NICU's air before it was relocated. CONCLUSION: The risk factors for Bacillus species sepsis in our NICU were NEC and PCVC. The clinical course was milder than previously described, and PCVC was successfully salvaged in most cases. The increase in the incidence could be related to the construction work connected with NICU's relocation.

Prevalence of enterotoxigenic Bacillus cereus and its enterotoxins in milk and milk products in and around Nairobi.

OBJECTIVES: To determine the prevalence of enterotoxigenic Bacillus cereus (B. cereus) and enterotoxins in milk and milk products. DESIGN: A random sampling of milk products was carried out. SETTING: Market milk and milk products were collected from retail shops in Nairobi and analysed for contamination with enterotoxigenic B. cereus and its enterotoxins using reverse passive latex agglutination and TECRA ELISA immunoassay tests. SUBJECTS: Ninety six milk samples including 36 raw milk, 42 pasteurised milk, 10 yogurt and eight fermented milk samples. Forty seven Bacillus cereus isolated from milk and milk products. MAIN OUTCOME MEASURES: Isolation of enterotoxigenic B. cereus from milk and milk products and detection of B. cereus hemolytic (hemolysin BL) and non-hemolytic enterotoxins in milk. RESULTS: Fifty seven percent of the samples were contaminated with B. cereus. Eighty one percent (38 out of 47) of the isolates produced non-hemolytic enterotoxins, while 25 (53.2%) of the isolates produced hemolysin BL. Eighteen (38.3%) of the isolates produced both hemolysin BL and non-hemolytic enterotoxins. About fourteen percent (14.3%) of the pasteurised milk samples tested positive for non-hemolytic enterotoxin. CONCLUSION: Enterotoxigenic B. cereus and enterotoxins occur in market milk and their presence poses a potential risk of causing food poisoning. The risk can be reduced if milk products undergo thorough quality control checks and are always kept at below 4 degrees C till consumption. Post pastuerisation contamination which is commonly blamed for spoilage of milk products by B. cereus is not necessarily the most important source of this organism.

Amplified fragment length polymorphism (AFLP) analysis of Clostridium novyi, C. perfringens and Bacillus cereus isolated from injecting drug users during 2000.

As part of the follow-up investigations associated with an outbreak of severe illness and death among illegal injecting drug users during 2000, 43 cultures of Clostridium novyi type A, 40 C. perfringens type A and 6 isolates of Bacillus cereus were characterised by amplified fragment length polymorphism (AFLP) analysis. Among the 43 C. novyi isolates, 23 different AFLP profiles were detected. The same AFLP profile was detected in isolates from 18 drug users investigated during 2000 from Scotland, England, the Republic of Ireland and Norway and a wound from a patient in 2000 who was not identified as a drug user. Unique AFLP profiles were obtained from four drug users from England and the Republic of Ireland, 10 historical isolates from culture collections, an isolate from food (1989) and three isolates from wounds (1995, 1991, 1988). The 40 C. perfringens isolates were from 13 drug users, the contents of one syringe and two samples of heroin. Sixteen AFLP types of C. perfringens were distinguished and there was little evidence for commonality among the isolates. The AFLP types of C. perfringens from heroin differed and were unique. Six isolates of B. cereus were from four drug users and two samples of heroin. Four different AFLP patterns were distinguished. Three AFLP types were isolated from four drug users. B. cereus isolates from an aspirate and a heroin sample collected from the same drug user were identical, and were also indistinguishable from an isolate from a groin infection in a second drug user. The AFLP type of the isolate from a second and unrelated heroin sample was unique. The AFLP results showed no or very limited evidence for commonality between the different isolates of B. cereus and C. perfringens. In marked contrast, the C. novyi isolates from the majority of the drug users during 2000 were homogeneous, suggesting a common source or clonal selection of a C. novyi type, or both, which either had an adaptive advantage in spore germination, survival or growth following the drug preparation and the injection procedure, or produced a more severe clinical presentation.

Neonatal intensive care unit: reservoirs of nosocomial pathogens.

Improvement in the care and treatment of neonates had contributed to their increased survival. Nosocomial infection remains an important problem in intensive care units. Hospital wards had been shown to act as reservoirs of pathogenic microorganisms associated with infection. To assess the prevalence of pathogenic organisms in the environment of the neonatal unit, 92 swabs were randomly collected from cots, incubators and various equipments in the unit and were cultured on Blood agar and MacConkey agar plates. Air contamination was detected by exposing the same types of agar plates for 3 hours in several areas of the unit. After 48 hours incubation, isolates were identified biochemically. There is marked congestion in the unit. Ninety one percent of swabs yielded growth, with coagulase negative Staphylococcus being the predominant organism (44%), followed by Bacillus species (20%), E. coli (12.5%), and Klebsiella (8.5%), Pseudomonas species (3.6%) and moulds (3.6%). Sedimentation plates had colony counts of from 10 - 100 per plate and the majority of the cultures were polymicrobial cultures. The presence of various Gram-negative bacili including known neonatal pathogens (like E. Coli and Pseudomonas) especially on ward equipment and congestion in the ward has the potential to cause nosocomial infection.

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.

Epidemiology and pathogenesis of Bacillus cereus infections.

Bacillus cereus is a causative agent in both gastrointestinal and in nongastrointestinal infections. Enterotoxins, emetic toxin (cereulide), hemolysins, and phoshpolipase C as well as many enzymes such as beta-lactamases, proteases and collagenases are known as potential virulence factors of B. cereus. A special surface structure of B. cereus cells, the S-layer, has a significant role in the adhesion to host cells, in phagocytosis and in increased radiation resistance. Interest in B. cereus has been growing lately because it seems that B. cereus-related diseases, in particular food poisonings, are growing in number.

Nosocomial pseudoepidemic caused by Bacillus cereus traced to contaminated ethyl alcohol from a liquor factory.

From September 1990 to October 1990, 15 patients who were admitted to four different departments of the National Taiwan University Hospital, including nine patients in the emergency department, three in the hematology/oncology ward, two in the surgical intensive care unit, and one in a pediatric ward, were found to have positive blood (14 patients) or pleural effusion (1 patient) cultures for Bacillus cereus. After extensive surveillance cultures, 19 additional isolates of B. cereus were recovered from 70% ethyl alcohol that had been used as a skin disinfectant (14 isolates from different locations in the hospital) and from 95% ethyl alcohol (5 isolates from five alcohol tanks in the pharmacy department), and 10 isolates were recovered from 95% ethyl alcohol from the factory which supplied the alcohol to the hospital. In addition to these 44 isolates of B. cereus, 12 epidemiologically unrelated B. cereus isolates, one Bacillus sphaericus isolate from a blood specimen from a patient seen in May 1990, and two B. sphaericus isolates from 95% alcohol in the liquor factory were also studied for their microbiological relatedness. Among these isolates, antibiotypes were determined by using the disk diffusion method and the E test, biotypes were created with the results of the Vitek Bacillus Biochemical Card test, and random amplified polymorphic DNA (RAPD) patterns were generated by arbitrarily primed PCR. Two clones of the 15 B. cereus isolates recovered from patients were identified (clone A from 2 patients and clone B from 13 patients), and all 29 isolates of B. cereus recovered from 70 or 95% ethyl alcohol in the hospital or in the factory belonged to clone B. The antibiotype and RAPD pattern of the B. sphaericus isolate from the patient were different from those of isolates from the factory. Our data show that the pseudoepidemic was caused by a clone (clone B) of B. cereus from contaminated 70% ethyl alcohol used in the hospital, which we successfully traced to preexisting contaminated 95% ethyl alcohol from the supplier, and by another clone (clone A) without an identifiable source.

An outbreak of Bacillus cereus respiratory tract infections on a neonatal unit due to contaminated ventilator circuits.

An outbreak of Bacillus cereus respiratory tract infections affecting six ventilated preterm neonates over a two-week period is described. Reusable ventilator circuits were identified as the cause of the outbreak. Ordinarily these were reprocessed on the Neonatal Unit (NNU), first through a washing machine and then through a low-temperature steam (LTS) disinfector. The onset of the outbreak coincided with a breakdown of the LTS facility, which necessitated sending the washed circuits off site for LTS disinfection. The washing machine was shown to be contaminated with the same serovars of B. cereus as those isolated from patients. Two critical steps in the off site LTS disinfection process allowed exsporulation and multiplication of B. cereus: the circuits were inadequately dried after processing, whilst return of the moist circuits to the NNU was often delayed. The outbreak was terminated by withdrawal of the heat-disinfected ventilator circuits. This outbreak emphasizes the need for high standards where medical equipment is reprocessed, especially for use in vulnerable patients.

An outbreak of Bacillus species in a cancer hospital.

Bacillus species were recovered from the blood cultures of 39 oncology patients over 14 weeks. A matched case-control study showed a strong association of Bacillus species bacteremia with use of calcium gluconate solution (odds ratio=25.0) and of central venous lines (odds ratio=8.8). Stopping use of the implicated calcium gluconate vials controlled the outbreak.

[Epidemic outbreak in a home for the aged caused probably by Bacillus cereus]. / Brote epidémico en una residencia de ancianos de probable etiología por Bacillus cereus.

OBJECTIVES: To identify the causative agent and the factors precipitating the outbreak. DESIGN: Observational, crossover study. SETTING: Las Delicias Health district, Jerez de la Frontera. PATIENTS AND OTHER PARTICIPANTS: The population exposed, belonging to an elderly persons' home. MEASUREMENTS AND MAIN RESULTS: The total number of people exposed was the 425 persons living in an elderly persons' home in Jerez in November 1995. The clinical histories were reviewed, and a specific questionnaire used to interview 77 ill persons and 77 healthy ones. The criteria for ill cases were presence of vomiting and/or diarrhoea. 32.6% of the ill people had fundamentally vomiting; 24.67% diarrhoea, 37.66% vomiting plus diarrhoea, and 100% ran no temperature. Positive and significant OR were detected in various foods (from 2.36 to 10.52 OR). We isolated 3,000,000, and up to 5,600,000, colonies of Bacillus cereus per gram in several foods. We observed incorrect practices in the conservation and handling of foods. CONCLUSIONS: Epidemiological, microbiological and clinical indications placed us before an outbreak of food poisoning probably caused by Bacillus cereus. The intervention at critical points, inter-institution coordination and communication in time and with data between professionals (microbiologist, doctors, nurses, vets and epidemiologist) were decisive in solving the outbreak.

Use of pulsed-field gel electrophoresis to investigate a pseudo-outbreak of Bacillus cereus in a pediatric unit.

Bacillus cereus is a well-known cause of food poisoning. It also causes rare systemic infections, usually in immunocompromised patients. Dissemination of this species in hospitals had been reported. Most of these episodes were pseudo-outbreaks and were usually secondary to equipment or environmental contamination. We report here on the use of pulsed-field gel electrophoresis (PFGE) to analyze a pseudo-outbreak of B. cereus in a pediatric unit. Different restriction endonucleases had been tested, and SmaI was found to give the best result for PFGE. Among the 26 clinical isolates of B. cereus and the type strain of the species, 15 distinct PFGE patterns were distinguished. PFGE after DNA macrorestriction with SmaI could clearly differentiate between the epidemiologically related isolates and the unrelated isolates. Because the same epidemic strain of B. cereus was isolated from the settle plates which were exposed near the outlet of the ventilation system, the source of this pseudo-outbreak was suspected to be the unit's air filtration system. This is one of the first reports of the application of PFGE to the study of B. cereus, and this method is useful for epidemiological investigation.