Panophthalmitis after a blood transfusion; responsible organism, Bacillus cereus

Mapping prognostic factors for globe survival in panophthalmitis using logistic regression and Cox proportional hazard models: A retrospective study

Purpose

The aim of this study was to report the outcomes of panophthalmitis and to identify factors significantly affecting globe survival in the disease.

Methods

This was a retrospective study on patients with panophthalmitis in a tertiary hospital between January 1, 2017, and December 31, 2019. The demographics, treatment details, culture results, and final outcomes were recorded. Logistic regression and Cox proportional hazards (CPH) were calculated to identify variables associated with globe loss. A P < 0.05 was considered significant.

Results

Eighty-five eyes of 85 patients (31 culture positive) were eligible for review. The mean age of the participants was 55.21 ± 20.17 years with a male-to-female ratio of 2.04:1. Corneal ulcer (38.82%; n = 33) and open globe injuries (OGIs) (38.82%; n = 33) were the most common etiologies. Pseudomonas aeruginosa (n = 10; 11.76%) was the most common isolate. The mean duration of hospital stay was 7.58 ± 2.32 days. Overall, 44 (51.76%) globes could be salvaged. The need for evisceration (P = 0.901) and hospital stays (P = 0.095) were similar for culture-positive and -negative cohorts. The unadjusted logistic regression and CPH models showed that culture sterility did not affect globe survival [OR = 1.210 (0.501-2.950), P = 0.668; HR = 1.176 (0.617-2.243), P = 0.623]. The adjusted logistic regression and the CPH models showed that corneal ulcers [OR = 10.900 (2.460-48.200), P = 0.002; HR = 5.393 (1.603-18.140), P = 0.006] and OGI [OR = 7.360 (1.650-32.700), P = 0.009; HR = 4.548 (1.321-15.660), P = 0.016] were significantly associated with globe loss.

Conclusion

Corneal ulcer or OGI as the primary etiology is detrimental to globe survival in panophthalmitis.

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.

Bacillus cereus and related species

Bacillus cereus is a gram-positive aerobic or facultatively anaerobic spore-forming rod. It is a cause of food poisoning, which is frequently associated with the consumption of rice-based dishes. The organism produces an emetic or diarrheal syndrome induced by an emetic toxin and enterotoxin, respectively. Other toxins are produced during growth, including phospholipases, proteases, and hemolysins, one of which, cereolysin, is a thiol-activated hemolysin. These toxins may contribute to the pathogenicity of B. cereus in nongastrointestinal disease. B. cereus isolated from clinical material other than feces or vomitus was commonly dismissed as a contaminant, but increasingly it is being recognized as a species with pathogenic potential. It is now recognized as an infrequent cause of serious nongastrointestinal infection, particularly in drug addicts, the immunosuppressed, neonates, and postsurgical patients, especially when prosthetic implants such as ventricular shunts are inserted. Ocular infections are the commonest types of severe infection, including endophthalmitis, panophthalmitis, and keratitis, usually with the characteristic formation of corneal ring abscesses. Even with prompt surgical and antimicrobial agent treatment, enucleation of the eye and blindness are common sequelae. Septicemia, meningitis, endocarditis, osteomyelitis, and surgical and traumatic wound infections are other manifestations of severe disease. B. cereus produces beta-lactamases, unlike Bacillus anthracis, and so is resistant to beta-lactam antibiotics; it is usually susceptible to treatment with clindamycin, vancomycin, gentamicin, chloramphenicol, and erythromycin. Simultaneous therapy via multiple routes may be required.

In vitro susceptibilities of ocular Bacillus cereus isolates to clindamycin, gentamicin, and vancomycin alone or in combination

A broth dilution assay was used to determine the in vitro susceptibilities of 10 ocular isolates of Bacillus cereus to clindamycin, gentamicin, and vancomycin both alone and in combination. The checkerboard technique was used to determine fractional inhibitory and bactericidal concentration indices for combinations of clindamycin-gentamicin and vancomycin-gentamicin.

Bacillus species

The genus Bacillus is a diverse group of gram-positive, spore-forming aerobic bacilli. B anthracis, the agent of anthrax, is primarily an animal pathogen but is capable of causing human infection, most commonly of the skin or lungs. B cereus, a well-recognized cause of gastroenteritis, may occasionally cause epidemics in health institutions. Both B cereus and other Bacillus species are increasingly recognized as opportunistic pathogens in the hospitalized patient. This report is intended as a comprehensive review of the bacteriology, clinical features, and therapy of Bacillus spp infections. Nosocomial epidemics and transmission will be highlighted.

Metastatic bacterial endophthalmitis: a contemporary reappraisal

Metastatic bacterial endophthalmitis remains a challenge to the clinician despite the success of antibiotics in reducing its frequency and severity. Controversy currently surrounds the management of this condition because of uncertainty about the value of and indications for vitreous surgery. We review 72 cases of metastatic endophthalmitis from the past decade, including five not previously published. The spectrum of causative bacteria changed significantly during this period, with displacement of meningococcus by Bacillus cereus as the most frequently reported agent and an increasing incidence of infection by organisms of low pathogenicity in immunologically compromised hosts. We propose a new classification scheme for metastatic endophthalmitis based on the location (anterior or posterior segment) and extent (focal or diffuse) of the primary intraocular infection. Focal and anterior cases appear to have a good prognosis, while posterior diffuse disease nearly always leads to blindness. Our analysis of outcomes suggests that systemic antibiotics are more valuable in metastatic than in postoperative or traumatic endophthalmitis and that intraocular antibiotic injection and vitrectomy make only a limited contribution to successful treatment in metastatic infection. We recommend a clinical approach to metastatic endophthalmitis that minimizes exposure of patients to the risks of invasive procedures.

Fulminating panophthalmitis due to exogenous infection with Bacillus cereus: report of 4 cases

Bacillus cereus is a seldom recognised but important cause of panophthalmitis. Although most reported cases have been the result of endogenous infection, we have recently seen 4 cases that followed ocular trauma. In each instance a fulminating panophthalmitis developed, accompanied by fever and leucocytosis. Despite prompt therapy all eyes were rapidly lost. In view of the selective antibiotic sensitivities of this organism and the fulminating course of the disease, conventional approaches to therapy, including standard prophylactic antibiotic regimens, are unlikely to be successful in such cases. Analysis of our cases suggest that ocular infection with B. cereus has certain features that may allow a provisional diagnosis to be made before isolation of the organism. Early recognition and prompt institution of effective therapy may lead to salvage of these eyes in the feature.

The problem of bacillus species infection with special emphasis on the virulence of Bacillus cereus

Although Bacillus cereus is an uncommon ocular pathogen, infection with it usually results in loss of the eye. Although previous reports have emphasized endogenous infection, our recent experience indicates the importance of B cereus infection following trauma. Management is hampered by ineffectiveness of current empirical antibiotic regimens. This microorganism is resistant to both the penicillins and the cephalosporins. Although B cereus is susceptible to gentamicin, our studies indicate that gentamicin by itself is inadequate to eradicate the infection. B cereus, however, is susceptible to clindamycin and combined therapy with gentamicin and clindamycin appears to offer the best approach. Early diagnosis is the key to successful treatment. We believe the clinical circumstances likely to lead to B cereus infection, as well as the manifestations of the disease itself, are sufficiently distinctive to alert the ophthalmologist to the possibility of this infection. Prompt recognition of the infection should allow institution of appropriate therapy before permanent structural changes occur.

[A fatal food poisoning caused by bacillus cereus (author's transl)]

The autopsy of a 37 year old man who had died under extraordinary circumstances showed a bromatoxism by bacillus cereus. The verification of the bacillus was possible although the man had already died 2-3 days before; and that in spite of the existence of early beginning rottenness. With the help of morphological findings the pathogenetic effect of the toxins (exotoxin and enterotoxin) of bacillus cereus is discussed. Blood cultures of the heart alone are not sufficient to prove a causal connexion between infection and death. For this purpose bacteriological examination of the organs (liver, spleen, kidney, lungs and brain) is at the same time necessary. An aseptic method, which is described in detail, is the absolute condition for useful results. The forensic value of proof of the bacteriological examination is secured and improved by an additional verification of bacteria in histological specimen coloured by Gram.

Endogenous E. coli endophthalmitis

A case of Escherichia coli septicemia with associated metastatic en dophthalmitis and endocarditis is presented. The ocular signs and symptoms were the initial manifestations of sepsis. Irreversible damage to the eye occurred in less than 24 hours. The pattern of metastatic bacterial endophthalmitis has changed since the introduction of potent antimicrobial agents, with an increased incidence of Gram-negative bacillemia. E. coli endophthalmitis carries a poor prognosis. Early diagnosis and systemic treatment will prevent the life-threatening complications of sepsis.