Clostridium perfringens meningitis, Plesiomonas shigelloides sepsis: A lethal combination

Rapid and sensitive detection of Plesiomonas shigelloides by cross‑priming amplification of the hugA gene

Plesiomonas shigelloides (P. shigelloides) is implicated as an aetiological agent of human gastroenteritis in humans, for which reliable laboratory detection of P. shigelloides is clinically and epidemiologically desirable. A simple molecular method for rapid detection of P. shigelloides using cross-priming amplification (CPA) has been developed, with hugA as the target. The hugA gene is required for haem iron utilisation and is critical for the survival and growth of P. shigelloides. The assay output was visualised as a colour change with no need to open the reaction tubes, and no false-positive results were detected for the 33 non- P. shigelloides strains examined to assess assay specificity. The limit of detection was 200 fg P. shigelloides DNA per reaction and 3×10³ CFU per g in human stools, which was 100 and 10-fold more sensitive than polymerase chain reaction, respectively. The CPA method was used to detect the presence of P. shigelloides in stool specimens from 70 patients with diarrhoea and 30 environmental water samples, with no difference in accuracy between the CPA assay and the biological culture. The present study, therefore, suggests that the P. shigelloides hugA CPA assay may represent a valuable tool for rapid and sensitive detection of P. shigelloides in primary care facilities and clinical laboratories.

Plesiomonas shigelloides Revisited

After many years in the family Vibrionaceae, the genus Plesiomonas, represented by a single species, P. shigelloides, currently resides in the family Enterobacteriaceae, although its most appropriate phylogenetic position may yet to be determined. Common environmental reservoirs for plesiomonads include freshwater ecosystems and estuaries and inhabitants of these aquatic environs. Long suspected as being an etiologic agent of bacterial gastroenteritis, convincing evidence supporting this conclusion has accumulated over the past 2 decades in the form of a series of foodborne outbreaks solely or partially attributable to P. shigelloides. The prevalence of P. shigelloides enteritis varies considerably, with higher rates reported from Southeast Asia and Africa and lower numbers from North America and Europe. Reasons for these differences may include hygiene conditions, dietary habits, regional occupations, or other unknown factors. Other human illnesses caused by P. shigelloides include septicemia and central nervous system disease, eye infections, and a variety of miscellaneous ailments. For years, recognizable virulence factors potentially associated with P. shigelloides pathogenicity were lacking; however, several good candidates now have been reported, including a cytotoxic hemolysin, iron acquisition systems, and lipopolysaccharide. While P. shigelloides is easy to identify biochemically, it is often overlooked in stool samples due to its smaller colony size or relatively low prevalence in gastrointestinal samples. However, one FDA-approved PCR-based culture-independent diagnostic test system to detect multiple enteropathogens (FilmArray) includes P. shigelloides on its panel. Plesiomonads produce β-lactamases but are typically susceptible to many first-line antimicrobial agents, including quinolones and carbapenems.

Gas-Forming Pyogenic Liver Abscess with Septic Shock

The pyogenic liver abscess caused by Clostridium perfringens (C. perfringens) is a rare but rapidly fatal infection. The main virulence factor of this pathogen is its α-toxin (lecithinase), which decomposes the phospholipid in cell membranes leading to cell lysis. Once the bacteria are in blood stream, massive intravascular hemolysis occurs. This can present as anemia on admission with evidence of hemolysis as indicated by low serum haptoglobin, high serum lactate dehydrogenase (LDH), elevated indirect bilirubin, and spherocytosis. The clinical course of C. perfringens septicemia is marked by rapidly deteriorating course with a mortality rate ranging from 70 to 100%. The very rapid clinical course makes it difficult to diagnose on time, and most cases are diagnosed at autopsy. Therefore it is important to consider C. perfringens infection in any severely ill patient with fever and evidence of hemolysis. We present a case of seventy-seven-year-old male with septic shock secondary to pyogenic liver abscess with a brief review of existing literature on C. perfringens.

Gas-forming liver abscess associated with rapid hemolysis in a diabetic patient

We experienced a case of liver abscess due to Clostridium perfringens (CP) complicated with massive hemolysis and rapid death in an adequately controlled type 2 diabetic patient. The patient died 6 h after his first visit to the hospital. CP was later detected in a blood culture. We searched for case reports of CP septicemia and found 124 cases. Fifty patients survived, and 74 died. Of the 30 patients with liver abscess, only 3 cases survived following treatment with emergency surgical drainage. For the early detection of CP infection, detection of Gram-positive rods in the blood or drainage fluid is important. Spherocytes and ghost cells indicate intravascular hemolysis. The prognosis is very poor once massive hemolysis occurs. The major causative organisms of gas-forming liver abscess in diabetic patients are Klebsiella pneumoniae (K. pneumoniae) and Escherichia coli (E. coli). Although CP is relatively rare, the survival rate is very poor compared with those of K. pneumoniae and E. coli. Therefore, for every case that presents with a gas-forming liver abscess, the possibility of CP should be considered, and immediate aspiration of the abscess and Gram staining are important.