Bacillus cereus meningitis in a term neonate

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.

Bacillus cereus meningoencephalitis in an immunocompetent patient

Central nervous system (CNS) infection from Bacillus cereus (B. cereus) is rare and usually occurs in immunosuppressed patients or in a presence of invasive CNS devices. Our case reported here is a very rare case of an immunocompetent elderly patient without any CNS devices who was diagnosed with B. cereus meningoencephalitis and bacteremia. According to our patient, preceding gastrointestinal (GI) symptoms and trans-sphenoidal hypophysectomy could be the precipitating factors. A positive blood culture should not be concluded as a contamination but prompt repeating another set of blood culture for a better clinical judgment. Given its abrupt clinical course and high mortality rate, high index of suspicion for rapid detection and management is needed for a preferable clinical outcome. Empiric treatment with intravenous vancomycin is reasonable before a susceptibility result becomes available.

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CNS infection from B. cereus is rare and usually associated with CNS devices or immunosuppression.

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B. cereus can cause meningoencephalitis in immunocompetent elderly patients without CNS device.

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B. cereus in blood culture is not always a contaminant. Repeating blood culture is recommended.

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Empiric treatment with vancomycin should be started before a susceptibility result is available.

The Food Poisoning Toxins of Bacillus cereus

Bacillus cereus is a ubiquitous soil bacterium responsible for two types of food-associated gastrointestinal diseases. While the emetic type, a food intoxication, manifests in nausea and vomiting, food infections with enteropathogenic strains cause diarrhea and abdominal pain. Causative toxins are the cyclic dodecadepsipeptide cereulide, and the proteinaceous enterotoxins hemolysin BL (Hbl), nonhemolytic enterotoxin (Nhe) and cytotoxin K (CytK), respectively. This review covers the current knowledge on distribution and genetic organization of the toxin genes, as well as mechanisms of enterotoxin gene regulation and toxin secretion. In this context, the exceptionally high variability of toxin production between single strains is highlighted. In addition, the mode of action of the pore-forming enterotoxins and their effect on target cells is described in detail. The main focus of this review are the two tripartite enterotoxin complexes Hbl and Nhe, but the latest findings on cereulide and CytK are also presented, as well as methods for toxin detection, and the contribution of further putative virulence factors to the diarrheal disease.

Bacillus cereus infection in neonates and the absence of evidence for the role of banked human milk: Case reports and literature review

BACKGROUND

Banked human milk (BHM) has inherent infectious risks, even when pasteurized. Because of the ubiquity of Bacillus cereus in the environment and its ability to resist the Holder pasteurization process, there is a concern that BHM might lead to severe B. cereus infections.

OBJECTIVE

We reviewed observed and published cases to determine the potential causal role of BHM as the source of these infections.

METHODS

Two infants in the province of Québec (Canada) developed a B. cereus neonatal infection, and both had received BHM. We conducted bacteriological studies to compare clinical isolates and those found in these cases.

RESULTS

After extended culture of BHM retention lots, B. cereus was found to have been involved in batches related to the first case. However, molecular typing showed that the strain was different from the clinical isolate, therefore excluding BHM as the source of contamination. In the second case, a Brevibacillus spp was isolated, a species distinct from the clinical isolate.

CONCLUSION

Based on these cases and others reported in the literature, a causal link between B. cereus contaminated BHM and preterm neonatal infection has never been documented. Therefore, the risk that BHM can cause this infection remains theoretical. Given the widespread presence of B. cereus in the hospital environment and its capacity to resist standard cleaning procedures, it seems likely that airborne or direct or indirect contact are the main sources of most, if not all, cases of severe B. cereus neonatal infections, even in babies exposed to BHM.

Chemotherapeutic control of Gram-positive infection in white sea bream (Diplodus sargus, Linnaeus 1758) broodstock

Aim:

This study aimed to identify the pathogenic bacteria responsible for the septicemic disease affecting white sea bream brooders and determining the sensitivity of the recovered isolates to different antibiotics followed by estimation of long-acting oxytetracycline (OTC) efficacy in controlling this disease, and finally, determining the proper dose regimen.

Materials and Methods:

Biolog microbial identification system was used for determination of the pathogens which are responsible for this disease. Agar disk diffusion test and minimum inhibitory concentration (MIC) were used to determine the antibiotic susceptibility of recovered isolates. Oxytetracycline (OTC) was used at a dose level of 100 mg/kg body weight for the treatment of diseased fish, and the OTC concentration in the serum samples was determined by high-performance liquid chromatography.

Results:

Fifteen Staphylococcus epidermidis and 11 Bacillus cereus isolates were recovered from the lesion of muscle, tail, eye, and heart blood. S. epidermidis isolates were sensitive to OTC, ciprofloxacin, enrofloxacin, spiramycin, erythromycin (E), and florfenicol. B. cereus isolates were sensitive to all mentioned antibiotics except E. Based on the MIC test, all B. cereus isolates were sensitive to OTC with MIC ranging between <0.125 and 4 µg/ml and 11 S. epidermidis isolates were sensitive with MIC ranging between <0.125 and 8 µg/ml, while four isolates were resistant. Different degrees of degenerative changes were present in the hepatopancreas, posterior kidney, eye, and skin tissues of diseased fish.

Conclusion:

Single intraperitoneal injection of long-acting OTC at a dose of 100 mg/kg body weight was effective in termination of S. epidermidis and B. cereus infection in white sea bream (D. sargus) broodstock.

Contaminated ventilator air flow sensor linked to Bacillus cereus colonization of newborns

We investigated Bacillus cereus–positive tracheal aspirates from infants on ventilators in a neonatal intensive care unit. Multilocus sequence typing determined a genetic match between strains isolated from samples from a case-patient and from the air flow sensor in the ventilator. Changing the sterilization method for sensors to steam autoclaving stopped transmission.

Bacillus cereus Bloodstream Infection in a Preterm Neonate Complicated by Late Meningitis

Central nervous system infections caused by Bacillus cereus have rarely been reported in infants. In this paper, the case of a 2-month-old low-birth-weight female who developed meningitis 45 days after resolution of a bloodstream infection (BSI) is described. The pulsed-field gel electrophoresis results revealed that the patterns of both B. cereus isolates responsible for the acute meningitis and for the prior bacteraemic episode were closely related. Although the source of the infection from within the patient was not clear, it is suggested that the B. cereus BSI developed in the neonate was complicated by acute meningitis.

Bacillus cereus, a volatile human pathogen

Bacillus cereus is a Gram-positive aerobic or facultatively anaerobic, motile, spore-forming, rod-shaped bacterium that is widely distributed environmentally. While B. cereus is associated mainly with food poisoning, it is being increasingly reported to be a cause of serious and potentially fatal non-gastrointestinal-tract infections. The pathogenicity of B. cereus, whether intestinal or nonintestinal, is intimately associated with the production of tissue-destructive exoenzymes. Among these secreted toxins are four hemolysins, three distinct phospholipases, an emesis-inducing toxin, and proteases. The major hurdle in evaluating B. cereus when isolated from a clinical specimen is overcoming its stigma as an insignificant contaminant. Outside its notoriety in association with food poisoning and severe eye infections, this bacterium has been incriminated in a multitude of other clinical conditions such as anthrax-like progressive pneumonia, fulminant sepsis, and devastating central nervous system infections, particularly in immunosuppressed individuals, intravenous drug abusers, and neonates. Its role in nosocomial acquired bacteremia and wound infections in postsurgical patients has also been well defined, especially when intravascular devices such as catheters are inserted. Primary cutaneous infections mimicking clostridial gas gangrene induced subsequent to trauma have also been well documented. B. cereus produces a potent beta-lactamase conferring marked resistance to beta-lactam antibiotics. Antimicrobials noted to be effective in the empirical management of a B. cereus infection while awaiting antimicrobial susceptibility results for the isolate include ciprofloxacin and vancomycin.

Successful surgical drainage and aggressive medical therapy in a preterm neonate with Bacillus cereus meningitis

Bacillus cereus meningitis is a rare disease with a very high mortality rate in neonates. The authors present the rare case of a premature infant with B. cereus bacteremia and subsequent intracranial abscesses. In addition to aggressive medical therapy, surgical drainage was performed via a left frontal mini-craniotomy. At 15 months of age, the patient had mild developmental delay, cortical blindness, and sensorineural hearing loss. The clinical case is described and difficulties in the management of B. cereus meningoencephalitis in infants are discussed.