Sarcina ventriculi of the stomach: A case report

Abstract

Sarcina ventriculi is a Gram positive organism, which has been reported to be found rarely, in the gastric specimens of patients with gastroparesis. Only eight cases of Sarcina, isolated from gastric specimens have been reported so far. Sarcina has been implicated in the development of gastric ulcers, emphysematous gastritis and gastric perforation. We report a case of 73-year-old male, with history of prior Billroth II surgery and truncal vagotomy, who presented for further evaluation of iron deficiency anemia. An upper endoscopy revealed diffuse gastric erythema, along with retained food. Biopsies revealed marked inflammation with ulcer bed formation and presence of Sarcina organisms. The patient was treated with ciprofloxacin and metronidazole for 1 wk, and a repeat endoscopy showed improvement of erythema, along with clearance of Sarcina organisms. Review of reported cases including ours suggests that Sarcina is more frequently an innocent bystander rather than a pathogenic organism. However, given its association with life threatening illness in two reported cases, it may be prudent to treat with antibiotics and anti-ulcer therapy, until further understanding is achieved.

Key Words: Sarcina ventriculi; Gram negative; Emphysematous gastritis; Gastric perforation; Bacterial overgrowth

Core tip:Sarcina ventriculi is a rare bacterium, seen in gastric biopsies of patients with gastroparesis. Only eight cases have been reported so far, where in it has been implicated in the development of gastric ulcers, emphysematous gastritis and gastric perforation. In our case, gastric erythema improved with antibiotic treatment. Given its association with life threatening illness in two reported cases, it may be prudent to treat with antibiotics and anti-ulcer therapy, until further understanding is achieved.

INTRODUCTION

Sarcina ventriculi is a Gram positive anaerobic bacterium, with carbohydrate fermentative metabolism as its sole energy source[1], and is able survive in very low pH environment[2]. Even though it is similar in appearance to Micrococcus species, certain morphological features (i.e., larger size, non-cluster forming pattern) help differentiate it from the latter organism[3].

Various reports in veterinary literature have implicated Sarcina in the development of gastric dilatation[4] and death of livestock, cats and horses[5,6]. Sarcina has also been reported to be found in feces of healthy humans consuming a predominantly vegetarian diet[7]. Recently, several reports have shown an association between Sarcina in the stomach and chronic nausea, dyspepsia, abdominal pain, gastric ulcers[3], and rarely emphysematous gastritis[8] and gastric perforation[9]. However Sarcina has also been found in gastric specimens without any other pathologic changes[3], suggesting that it may be a bystander rather than a pathogenic organism. To date, only eight cases of Sarcina ventriculi isolated from gastric biopsy specimens have been reported. We now report a case of Sarcina ventriculi of the stomach, associated with iron deficiency anemia and gastroparesis.

CASE REPORT

A 73-year-old male presented to the clinic for further evaluation of iron deficiency anemia. The patient had a history of medically refractory gastric ulcers in his 20 s, for which he underwent antrectomy and gastrojejunostomy (Billroth II) along with truncal vagotomy in 1985. He continued to be anemic since the surgery, with intermittent intake of oral iron replacement.

On initial evaluation for an incidentally detected anemia prior to unrelated urologic surgery, he did not have any gastrointestinal symptoms. The patient specifically denied nausea, vomiting, abdominal pain or weight loss. His complete blood count revealed decreased hemoglobin of 8.5 g/dL, decreased mean corpuscular volume of 63.2 fL, normal white cell count of 9.8 × 10⁹ L (normal 4.2 × 10⁹-10.2 × 10⁹ L) and elevated platelet count 415 × 10⁹ L (normal 151 × 10⁹-355 × 10⁹ L). Iron studies showed markedly reduced iron level of 12 mg/dL (normal 50-150 mg/dL), with an elevated total iron binding capacity of 490 mg/dL (normal 250-400 mg/dL) and reduced iron % saturation of 2% (normal 14%-50%).

Three years prior, an esophagogastroduodenoscopy (EGD) had revealed an anastomotic ulcer and polyps at the anastomotic site, the biopsies of which showed acute inflammation, but were otherwise unremarkable. A colonoscopy at that time was unremarkable except for diverticulosis. An EGD done during the current evaluation demonstrated diffuse gastric erythema, along with two 4mm polyps at the anastomosis (Figure 1). There was also a large amount of retained food in the stomach.

Figure 1 Esophagogastroduodenoscopy. A: Polyps at the anastamosis; B: Gastric erythema and food bezoar.

Tissue biopsies of the erythematous stomach revealed marked inflammation with ulcer bed formation, along with abundant bacterial overgrowth including the presence of Sarcina organisms (Figure 2). The Sarcina organisms were identified on routine hematoxylin and eosin (HE) stain, and no additional special stains or immunolabeling was performed. Based on prior studies[3], the tetrad morphology and size are characteristic enough to establish a diagnosis without further ancillary testing. Biopsies were negative for Helicobacter pylori, both by routine HE staining and by immunohistochemical staining. Aspirates from the small bowel also came back positive for small intestinal bacterial overgrowth, with > 100  000 cfu/mL of mixed Gram-positive and Gram-negative flora.

Figure 2 Characteristic 8-10 micron tetrads of Sarcina organisms (circled) were identified on endoscopic biopsy. The background shows abundant bacterial overgrowth and debris from retained food. Separate fragments of ulcer bed were present (not pictured) (hematoxylin and eosin; original magnification × 1000 oil lens).

The patient was treated with metronidazole 250 mg three times a day and ciprofloxacin 250 mg twice daily for 1 wk, along with daily sucralfate. He also received intravenous (IV) iron 300 mg × 2 doses followed by oral iron and achieved normal iron stores and hemoglobin levels. Subsequent follow up with a repeat EGD 3 mo later showed improvement of gastric erythema, and absence of food bezoar (Figure 3). Aspirates from the small bowel continued to suggest small intestinal bacterial overgrowth, with > 100  000 cfu/mL. However, repeat biopsies from the stomach were negative for Sarcina organisms, and showed features of chronic gastritis. Clinically, the patient’s perception of overall health improved with the above treatment, and he continued to be free of gastrointestinal symptoms.

Figure 3 Repeat esophagogastroduodenoscopy showing improvement of gastric erythema.

DISCUSSION

While the pathogenic role of Sarcina in the veterinary literature is well established, its role in human disease is not entirely clear. Since the initial description in 1842, the pathogenic role in humans has been questioned, as it has been found in the blood[10] and feces[7] of healthy humans.

Over the last three years, 8 cases[3,8,9] of Sarcina associated with endoscopic biopsies have been reported. While all these patients presented with various gastrointestinal symptoms (nausea, vomiting, epigastric pain, dyspepsia) only two patients had associated life threatening complications of emphysematous gastritis[8] and gastric perforation[9] (Table 1). Our patient did not have any gastrointestinal symptoms, and Sarcina was found incidentally, when gastric biopsies were performed for erythematous mucosa.

Table 1 Clinical, endoscopic and histological features of the eight reported cases of Sarcina ventriculi in the literature.

Case No.	Age	Sex	Symptoms/clinical findings	Endoscopic findings	Histologic findings	Treatment	Follow-up
1	14	Male	Abdominal pain	Not performed	Diffuse acute hemorrhagic gastritis and Sarcina organisms	Gentamicin and metronidazole	Symptoms improved after 5 d and patient discharged
			CT showed pneumoperitoneum.
			Intraoperatively there was necrotic stomach and gastric perforation and peritonitis
2	50	Male	Chronic nausea, vomiting	Esophagitis, duodenal lesion	Chronic superficial gastritis and ulcer with Sarcina organisms	Not available	Not available
3	3	Female	Vomiting, hematemesis Abdominal X-ray showed dilated stomach with intramural air	Gastric inflammation, blackening of mucosa, cobblestone appearance	Polymorphic inflammatory infiltrate with Sarcina organisms and gas bubbles	Imipene, fluconazole and omeprazole	Repeat endoscopy 6 mo later showed complete normalization
4	58	Female	Nausea and vomiting	Gastritis, food bezoar, inflammatory mass in duodenum	Active chronic gastritis with Sarcina organisms	Partial gastrectomy for obstruction	Treated for adenocarcinoma of pylorus
5	44	Female	Dyspepsia and substernal burning	Gastric ulcer and retained food	Non malignant gastric ulcer with Sarcina organisms	Omeprazole, ranitidine, metoclopramide	Symptoms improved
6	36	Male	Nausea, vomiting, epigastric pain in the setting of narcotic use	Retained food	Sarcina organisms without other histologic abnormalities	Received jejunostomy for malnutrition	Repeat biopsy negative for Sarcina organisms
7	12	Female	Dysphagia in the setting of esophageal atresia status post gastric pull through	Retained food, anastamotic stricture	Reflux esophagitis, Sarcina organisms	Information unavailable	Information unavailable
8	46	Female	Epigastric pain in the setting of pancreatic adenocarcinoma status post pancreatico-duodenectomy	Retained food and bile	Active chronic duodenitis with Sarcina organisms	No treatment	Continues spasms after 1 mo

CT: Computed tomography.

Another interesting feature is the presence of delayed gastric emptying in five of the eight reported cases. All of these patients had retained food in stomach during endoscopic examination. Similarly, our patient had a Billroth II with truncal vagotomy, which predisposed him to have delayed gastric emptying, as was evident by the gastric bezoar seen during endoscopic examination. Hence impaired emptying of stomach could potentially lead to the growth of Sarcina in the stomach.

The need for antibiotic treatment, when Sarcina is found in endoscopic biopsies of clinically stable patients is unknown. Of the reported cases, two patients with associated life threatening disease (i.e., emphysematous gastritis and gastric perforation) received intravenous antibiotics and recovered. One patient with non-life threatening disease was treated with combination of proton pump inhibitors and prokinetics, with good relief of symptoms. Some authors suggest that an underlying mucosal defect, such as erosion or ulceration, may predispose patients to more serious sequelae, from this otherwise ubiquitous organism[3]. We elected to treat our patient with antibiotics, as there was significant gastric erythema and ulceration, as well as small intestinal bacterial overgrowth.

In summary, Sarcina ventriculi is a rare bacterium, seen predominantly in patients with delayed gastric emptying. Review of the published cases along with our case suggests that it is more frequently an innocent bystander rather than a pathogenic organism. Given its association with life threatening illness in two reported cases, it may be prudent to treat with antibiotics and anti-ulcer therapy, until further understanding is achieved.