Identification and Containment of a Cluster of Two Bacillus cereus Infections in a Neonatal Intensive Care Unit

Late-onset sepsis in newborns caused by Bacillus Cereus: a case report and literature review

Bacillus cereus is a bacterium capable of causing late-onset neonatal sepsis. By analyzing 11 cases, this study investigates the diagnosis, treatment, and prognosis of Bacillus cereus infections, aiming to provide insights into clinical diagnosis and therapy. The study scrutinized 11 instances of late-onset neonatal sepsis, including two fatalities attributable to Bacillus cereus, one accompanied by cerebral hemorrhage. An examination and analysis of these cases' symptoms, signs, laboratory tests, and treatment processes, along with a review of related literature from 2010 to 2020, revealed a high mortality rate of 41.38% in non-gastrointestinal infections caused by Bacillus cereus. Our findings underscore the critical importance of rapid diagnosis and effective antimicrobial therapy in reducing mortality rates. Once the source of infection is identified, implementing effective infection control measures is essential.

Neonatal Bacillus cereus: an unusual case of congenital pneumonia requiring ECMO

A term neonate presented with cyanosis from birth, with refractory hypoxaemia despite intubation, administration of 100% oxygen and inhaled nitric oxide. Structural congenital heart disease was excluded. He developed profuse pulmonary haemorrhage at 6 hours of life with worsening hypoxia and was transferred to a paediatric intensive care unit (PICU) for initiation of veno-venous extracorporeal membrane oxygenation (vvECMO). Endotracheal aspirates from both the birth hospital and the PICU were positive for Bacillus cereus, with all other investigations finding no alternative cause for his presentation. Of note, mother was a practising veterinarian raising another potential source of exposure to this pathogen. A full recovery occurred after a total of 5 days of vvECMO, 13 days of ventilation and 20 days of PICU stay.

Investigating environmental transmission to resolve a Bacillus cereus group outbreak in a neonatal intensive care unit using core genome multilocus sequence typing

BACKGROUND

We analyzed an outbreak of Bacillus cereus group (Bcg) at a single-center neonatal intensive care unit level IV by conducting comprehensive sampling of both patients and the environment.

METHODS

Between 06/2020 and 10/2021, all Bcg isolates identified by both regular colonization screening and additional sampling of the environment were subjected to whole-genome sequencing, followed by in vitro extraction of MLST ST, resistance genes and virulence factors. Using publicly available genome sequences, we defined an ad hoc core genome multilocus sequence typing (cgMLST) scheme comprising 2759 target genes for Bcg typing, which we applied to the detected isolates. We have compared the results with a stable cgMLST that was published in the meantime and completed the investigation with a SNP analysis.

RESULTS

We analyzed 28 Bcg isolates from patient and environmental samples using MLST and cgMLST. This revealed multiple sequence types, with ST127 being the most common (n = 13). Both cgMLST schemes grouped ten of the 13 ST127 isolates into a cluster, including two invasive isolates from two different patients and several environmental samples. SNP analysis postulated a screen from a ventilation machine as a possible reservoir.

CONCLUSION

In sensitive settings such as neonatal intensive care units, considering the environment in outbreak analyses is crucial, especially when investigating potential transmission routes through shared devices. When dealing with widespread bacteria such as Bcg, high-resolution typing techniques are necessary. In this study, we successfully resolved an outbreak of Bcg infections using a custom cgMLST scheme combined with a SNP analysis.

Bacillus cereus Invasive Infections in Preterm Neonates: an Up-to-Date Review of the Literature

Bacillus cereus group species are widespread, Gram-positive, spore-forming environmental bacteria. B. cereus sensu stricto is one of the major causes of food poisoning worldwide. In high-risk individuals, such as preterm neonates, B. cereus infections can cause fatal infections. It is important to note that the phenotypic identification methods commonly used in clinical microbiology laboratories make no distinction between B. cereus sensu stricto and the other members of the group (Bacillus anthracis excluded). As a result, all the invasive infections attributed to B. cereus are not necessarily due to B. cereus sensu stricto but likely to other closely related species of the B. cereus group. Next-generation sequencing (NGS) should be used to characterize the whole genome of the strains belonging to the B. cereus group. This could confirm whether the strains involved in previously reported B. cereus invasive infections preferentially belong to formerly known or emerging individual species. Moreover, infections related to B. cereus group species have probably been overlooked, since their isolation in human bacteriological samples has for a long time been regarded as an environmental contaminant of the cultures. Recent studies have questioned the emergence or reemergence of B. cereus invasive infections in preterm infants. This review reports our current understanding of B. cereus infections in neonates, including taxonomical updates, microbiological characteristics, bacterial identification, clinical features, host-pathogen interactions, environmental sources of contamination, and antimicrobial resistance.

Fulminant Necrotizing Soft-tissue Infection in an Extremely Low Gestational Age Infant

We report a case of rapidly progressive necrotizing skin and soft-tissue infection caused by Bacillus cereus in an extremely low for gestational age infant. This case reminds clinicians to consider this opportunistic pathogen as the etiologic agent in fulminant necrotizing infections in vulnerable hosts, and to institute appropriate therapy in a timely fashion.

Update on Coagulase-Negative Staphylococci-What the Clinician Should Know

Coagulase-negative staphylococci (CoNS) are among the most frequently recovered bacteria in routine clinical care. Their incidence has steadily increased over the past decades in parallel to the advancement in medicine, especially in regard to the utilization of foreign body devices. Many new species have been described within the past years, while clinical information to most of those species is still sparse. In addition, interspecies differences that render some species more virulent than others have to be taken into account. The distinct populations in which CoNS infections play a prominent role are preterm neonates, patients with implanted medical devices, immunodeficient patients, and those with other relevant comorbidities. Due to the property of CoNS to colonize the human skin, contamination of blood cultures or other samples occurs frequently. Hence, the main diagnostic hurdle is to correctly identify the cases in which CoNS are causative agents rather than contaminants. However, neither phenotypic nor genetic tools have been able to provide a satisfying solution to this problem. Another dilemma of CoNS in clinical practice pertains to their extensive antimicrobial resistance profile, especially in healthcare settings. Therefore, true infections caused by CoNS most often necessitate the use of second-line antimicrobial drugs.

Genomic and Toxigenic Heterogeneity of Bacillus cereus sensu lato Isolated from Ready-to-Eat Foods and Powdered Milk in Day Care Centers in Colombia

Bacillus cereus sensu lato (s.l.) is a group of bacteria commonly found in diverse environments, including foods, with potential to cause emesis and diarrhea. In Colombia, it is one of the main foodborne pathogens. The aim of this study was to determine the genomic and toxigenic heterogeneity of B. cereus s.l. isolated from ready-to-eat foods and powdered milk collected in day care centers of Medellin, Colombia. Of 112 B. cereus s.l. isolates obtained, 94% were β-hemolytic. Toxigenic heterogeneity was established by the presence of nheABC, hblCDAB, cytK2, entFM, and cesB toxigenic genes. The nheABC operon and entFM gene were most frequently detected in the isolates, whereas the cesB gene was not found. According to the toxin genes content, nine toxigenic profiles were identified. A 44% of isolates had profiles with all genes for nonhemolytic enterotoxin, hemolysin BL, and enterotoxin FM production (profiles II and IV). Pulsed-field gel electrophoresis analysis indicated a high genomic heterogeneity among the B. cereus s.l., with 68 isolates grouping into 16 clusters and 33 placed separately in the dendrogram. This study provides useful information on the safety of ready-to-eat foods and powdered milk in day care centers where children, a susceptible population, are exposed and it should incentive for more studies to understand the distribution of different toxin-encoding genes among B. cereus s.l. isolates, enabling detailed risk assessment.

Alteration of antibiotic regimen as an additional control measure in suspected multi-drug-resistant Enterobacter cloacae outbreak in a neonatal intensive care unit

BACKGROUND

Increased occurrence of a particular species of Gram-negative bacteria (GNB), especially when multi-drug-resistant (MDR), in routine screening surveillance in neonatal intensive care units (NICUs) can be evoked by selection pressure.

AIM

To evaluate adaptation of the empiric antibiotic regimen for its usefulness as a control measure in suspected outbreaks in the NICU.

METHODS

In a retrospective outbreak analysis, cases between 1^st December 2017 and 31^st March 2018 were identified through microbiology and hygiene surveillance records. Furthermore, risk factors for MDR-GNB colonization were collected. Whole-genome sequencing (WGS) was performed on all isolates. Control measure documentations and interviews were employed to define interventions. As well as infection control measures, administration of third-generation cephalosporins was avoided and replaced whenever clinically acceptable as part of the intervention bundle.

FINDINGS

In total, nine patients were found to have rectal colonization with third-generation cephalosporin-resistant Enterobacter cloacae in routine screening surveillance in the pre-intervention period. After implementation of an infection control bundle, the incidence declined rapidly. WGS analysis revealed that two MDR E. cloacae were transmitted, and the majority were new cases. The incidence density of MDR-GNB colonization was 7.94/1000 patient-days (PD) before the intervention and 1.68/1000 PD during the altered antibiotic regimen. No infections with MDR-GNB occurred during the study.

CONCLUSIONS

Altering the antibiotic regimen with regard to selection pressure may be considered as part of an intervention bundle to rapidly control the emergence of MDR-GNB in suspected outbreak situations in the NICU.