Antimicrobial treatment of pancreatic infection in cats

ACVIM consensus statement on pancreatitis in cats

Background

Pancreatitis in cats, although commonly diagnosed, still presents many diagnostic and management challenges.

Objective

To summarize the current literature as it relates to etiology, pathogenesis, diagnosis, and management of pancreatitis in cats and to arrive at clinically relevant suggestions for veterinary clinicians that are based on evidence, and where such evidence is lacking, based on consensus of experts in the field.

Animals

None.

Methods

A panel of 8 experts in the field (5 internists, 1 radiologist, 1 clinical pathologist, and 1 anatomic pathologist), with support from a librarian, was formed to assess and summarize evidence in the peer reviewed literature and complement it with consensus clinical recommendations.

Results

There was little literature on the etiology and pathogenesis of spontaneous pancreatitis in cats, but there was much in the literature about the disease in humans, along with some experimental evidence in cats and nonfeline species. Most evidence was in the area of diagnosis of pancreatitis in cats, which was summarized carefully. In contrast, there was little evidence on the management of pancreatitis in cats.

Conclusions and Clinical Importance

Pancreatitis is amenable to antemortem diagnosis by integrating all clinical and diagnostic information available, and recognizing that acute pancreatitis is far easier to diagnose than chronic pancreatitis. Although both forms of pancreatitis can be managed successfully in many cats, management measures are far less clearly defined for chronic pancreatitis.

Triaditis: Truth and Consequences

Clinical findings with triaditis and individual disease components overlap and may include hyporexia, weight loss, lethargy, vomiting, diarrhea, dehydration, icterus, abdominal pain, thickened bowel loops, pyrexia, dyspnea, and shock. A definitive diagnosis of triaditis requires histologic confirmation of inflammation in each organ, but this may not be possible because of financial or patient-related constraints. Evidence-based data indicate that histologic lesions of triaditis are present in 30% to 50% of cats diagnosed with pancreatitis and cholangitis/inflammatory liver disease. Treatment of triaditis is based on the overall health status of the patient and the type and severity of disease in component organs.

A retrospective study of 157 hospitalized cats with pancreatitis in a tertiary care center: Clinical, imaging and laboratory findings, potential prognostic markers and outcome

BACKGROUND

Pancreatitis in cats (FP) has been increasingly diagnosed in recent years, but clinical studies of large numbers of affected cats are scarce.

OBJECTIVES

To describe a large cohort of cats with FP requiring hospitalization.

ANIMALS

One hundred and fifty-seven client-owned cats.

METHODS

Retrospective study, including cats diagnosed with pancreatitis based on sonographic evidence, positive SNAP feline pancreatic lipase immunoreactivity test results, increased 1,2-o-dilauryl-rac-glycerol-glutaric Acid-(6'-methylresorufin ester)-lipase activity, histopathology, or some combination of these.

RESULTS

One-hundred and twenty-two cats (77.7%) survived to discharge. Median time from onset of clinical signs to presentation was longer (P = .003) in nonsurvivors. Causes of FP included recent general anesthesia, trauma, hemodynamic compromise, and organophosphate intoxication, but most cases (86.6%) were idiopathic. Ultrasonographic findings consistent with pancreatitis were documented in 134 cats, including pancreatomegaly (81.3%), decreased (31.3%), or increased (14.9%) pancreatic echogenicity, extra-hepatic biliary tract dilatation (24%), and increased peri-pancreatic echogenicity (13%). Lethargy (P = .003), pleural effusion (P = .003), hypoglycemia (P = .007), ionized hypocalcemia (P = .016), azotemia (P = .014), parenteral nutrition administration (P = .013), and persistent anorexia during hospitalization (P = .001) were more frequent in nonsurvivors, whereas antibiotics were more frequently administered to survivors (P = .023). Nevertheless, when Bonferroni's correction for multiple comparisons was applied, none of the variables was statistically significant.

CONCLUSIONS AND CLINICAL IMPORTANCE

Previously unreported, clinically relevant, potential prognostic factors, including hypoglycemia, azotemia, parenteral nutrition, and withholding antibacterial treatment were identified in this exploratory study. These preliminary results should be examined further in confirmatory studies.

Pancreatic Abscess in a cat due to Staphylococcus aureus infection

A 16-year-old spayed female American Shorthair cat was presented with lethargy, anorexia, and wamble. Physical and blood examination did not reveal any remarkable findings. Abdominal ultrasonography identified the presence of a localized anechoic structure with a thick wall in contact with the small intestine and adjacent to the liver. Ultrasound-guided fine-needle aspiration of the structure revealed fluid containing numerous cocci and neutrophils. Two days after antibiotic treatment, exploratory laparotomy was performed and the content of the structure was removed before multiple lavages. The pathological and bacteriological examination results supported a confirmatory diagnosis of pancreatic abscess due to Staphylococcus aureus infection, making this the first such report in a cat. The cat remained healthy thereafter with no disease recurrence.

Prophylactic use of antibiotics in treatment of severe acute pancreatitis

Necrotic pancreatic infection is the most serious complication of severe acute pancreatitis (SAP). Although prophylactic antibiotics are widely used to reduce its death rate, its practical efficiency still remains controversial. Therefore, the clinical experiences with prophylactic use of antibiotics are summarized in this paper, hoping to offer certain guides to its treatment. However, results from recent studies do not support prophylactic use of antibiotics in all cases of necrotic pancreatic infection and suggest that only imipenem or meropenem can be used for no more than three weeks in patients with their pancreatic necrosis area >30% or in patients with biliogenic pancreatitis to decrease the risk of necrotic infection and its mortality rate.

The role of antibiotic prophylaxis in the treatment of acute pancreatitis

Acute pancreatitis is an inflammatory disorder, but it is not generally caused by infectious agents. Yet, in tertiary referral hospitals, the majority of patients who die of necrotizing pancreatitis do so as a consequence of infectious complications. These generally develop late (2-4 weeks) in the disease process. This finding prompted the hypothesis that infectious pancreatitis complications, such as an abscess or an infected necrosis which can lead to death, can be reduced by treating patients who suffer, at least initially, from a sterile inflammatory disorder, with broad-spectrum antibiotics. Here we review the experimental foundations of this hypothesis, as well as the difficulties that were encountered when clinical trials were undertaken to confirm it. At present, there is still a case for treating necrotizing pancreatitis patients with broad-spectrum antibiotics (specifically carbapenems), but the extent of the beneficial effect and the number of patients expected to profit from this approach should not be overestimated.

The effect of combination therapy of hyperbaric oxygen, meropenem, and selective nitric oxide synthase inhibitor in experimental acute pancreatitis

Despite the new diagnostic and therapeutic advancements, acute pancreatitis has still high rate of morbidity and mortality. We aimed to evaluate the effects of hyperbaric oxygen (HBO) therapy alone or combined with S-methylisothiourea (SMT), and meropenem (MER) therapy in an experimental rat model of acute necrotizing pancreatitis. Rats were randomly divided into 8 groups, and acute pancreatitis was induced in all groups except group 1. Treatment protocols were saline for group 2, SMT for group 3, SMT + MER for group 4, SMT + HBO for group 5, HBO for group 6, HBO + MER for group 7, and MER for group 8. All surviving animals were killed 48 hours after the induction of pancreatitis, and specimens were collected. Oxidative stress parameters, histopathologic scores and amylase levels were better in treatment groups than in the positive control group (group 2). The most favorable results were obtained in HBO treatment groups, especially in HBO + MER group (group 7). Our results indicate that adding HBO therapy to the antibiotic therapy will decrease oxidative stress parameters, serum amylase levels, and histopathological score. We suggest that adding the HBO therapy as an adjunctive to the treatment protocol of acute necrotizing pancreatitis may yield improvement in the morbidity and mortality of the disease.

Is late antibiotic prophylaxis effective in the prevention of secondary pancreatic infection?

BACKGROUND

Secondary infection of the inflamed pancreas is the principal cause of death after severe acute pancreatitis (AP). Although patients are not always managed early in the course of AP in clinical practice, prophylactic antibiotics that were used in experimental studies in rats were always initiated early after induction of pancreatitis. The effectiveness of antibiotics initiated later is unknown.

AIM

The aim of this study was to compare the effectiveness of ciprofloxacin and meropenem initiated early versus later in the course of acute necrotizing pancreatitis (ANP) in rats.

METHODS

100 Sprague-Dawley rats were studied. ANP was induced in rats by intraductal injection of 3% taurocholate. Rats were divided randomly into five groups: group I rats received normal saline as a placebo, group II and IV rats received three times daily meropenem 60 mg/kg i.p. at 2 and 24 h, respectively and group III and V rats received twice daily ciprofloxacin 50 mg/kg i.p. at 2 and 24 h, respectively, after induction. At 96 h, all rats were killed for quantitative bacteriologic study. A point-scoring system of histological features was used to evaluate the severity of pancreatitis.

RESULTS

Meropenem and ciprofloxacin initiated 2 h after induction of pancreatitis significantly reduced the prevalence of pancreatic infection (p < 0.001 and p < 0.04, respectively) as compared to controls. Neither of the antibiotics initiated later during the course of AP caused a significant decrease in pancreatic infection in rats (p > 0.05). Although the rats treated early infected less frequently than the rats treated later, the comparison reached statistical significance only in the meropenem group (p < 0.02).

CONCLUSION

Early antibiotic treatment reduces pancreatic infection more efficiently than late antibiotic treatment in ANP in rats.

Role of the gut in the course of severe acute pancreatitis

INTRODUCTION

The pathogenesis of acute pancreatitis remains elusive. Sepsis and multiple organ failure continue to cause death (overall mortality rate, approximately 10%) despite immense improvements in supportive, radiologic, and surgical therapy. The gut appears to play a key role in the development of these complications.

AIM

To critically review the evidence implicating the gut in the pathogenesis of acute pancreatitis.

METHODS

Relevant English-language literature or abstracts cited in the MEDLINE database were reviewed.

RESULTS AND CONCLUSION

Gram-negative enteric organisms account for most infections of pancreatic necrosis and subsequent sepsis, which suggests the gut as a source. Intestinal permeability is increased early in patients with severe acute pancreatitis and correlates with endotoxemia, which suggests translocation as a possible mechanism. The pathogenesis of the deranged function of the gut mucosal barrier and the possible sites of increase in intestinal permeability are discussed. The gut also plays a role in priming neutrophils and the release of inflammatory cytokines, which initiate and propagate nearly all the detrimental consequences of severe inflammation and sepsis. Future research avenues and potential therapeutic measures that may restore and preserve gut barrier function are explored.

Penetration of meropenem and cefepim into pancreatic tissue during the course of experimental acute pancreatitis

INTRODUCTION

Recent data from experimental and clinical studies suggest that the antibiotics showing good penetration into the pancreas may reduce mortality by preventing pancreatic infection, which is the most important prognostic factor in acute pancreatitis.

AIM

To determine and compare pancreatic tissue concentrations of meropenem and cefepime at different stages of acute necrotizing pancreatitis in an animal model that has been shown to closely mimic severe human pancreatitis.

METHODOLOGY

Acute necrotizing pancreatitis was induced in rats by a standardized intraductal infusion of glycodeoxycholic acid and intravenous cerulein. Six hours (n = 30) and 48 hours (n = 30) after induction of pancreatitis, the rats were randomized to receive an intravenous 20 mg/kg injection of either meropenem or cefepime. Blood and the head of the pancreas were collected for determining antibiotic concentrations by high-performance liquid chromatography.

RESULTS

Meropenem concentrations in the pancreas at 6 hours of acute pancreatitis increased significantly and decreased at 48 hours of the disease, but were still higher than that in controls. Concentrations of cefepime in necrotic pancreatic tissue were significantly low either during the initial or later phase, but lower in latter, in which the necrosis was more evident. Tissue/serum concentration ratios of meropenem were significantly higher than those of cefepime. However, tissue concentrations of both antibiotics are much higher than the minimum inhibitory concentration values for the common microorganisms involved in pancreatic infections.

CONCLUSION

Although both antibiotics penetrate into the necrotic tissue in sufficient therapeutic concentrations, penetration of meropenem is much better than cefepime. However, good tissue penetration may not solely indicate efficacy of that antibiotic. Therefore, further experimental and clinical studies are needed to determine the therapeutic and prognostic efficacy of these agents.

Prophylactic antibiotics and pancreatic necrosis

Recent controlled clinical studies suggest a positive effect of early antibiotic treatment on late morbidity and mortality in severe acute pancreatitis. In contrast, widespread use of antibiotics may lead to an increased number of fungal infections and multiresistant bacteria. Optimal choice, duration, and route of administration of the antibiotic agent(s) are far from being established. The additional administration of an antifungal agent with prophylactic intention cannot be supported by the currently available data.

Preventing pancreatic infection in acute pancreatitis

In acute pancreatitis, pancreatic inflammation may be complicated by the development of pancreatic infection with a high associated mortality. Pancreatic infection is related to the extent of pancreatic inflammation and necrosis and typically occurs in the second or third week of severe disease. It may be associated with a wide range of Gram-positive and Gram-negative bacteria, notably enterobacteria and also with Candida spp. Current surgical practice in the UK is to use prophylactic antimicrobial therapy in patients with severe disease, with the aim of preventing secondary pancreatic infection. Experimental evidence demonstrates that prophylactic antibacterial therapy prevents pancreatic infection and reduces mortality. Furthermore, studies of antibacterial prophylaxis in patients with acute pancreatitis suggest that prophylactic antibacterial therapy is associated with a reduction in mortality, particularly in those with severe disease. In general, broad-spectrum antibiotics have been used in animal and human studies. However, current evidence does not allow comparisons to be made between different antimicrobial agents. Nutritional strategies may also be important in the prevention of pancreatic infection. Enteral, rather than parenteral, nutrition has been associated with an improved clinical outcome in severe pancreatitis.

The role of antibiotic prophylaxis in the treatment of acute pancreatitis

Infected necrosis in acute pancreatitis is one of the most dreaded complications of acute pancreatitis. Whereas selection of an appropriate antibiotic treatment of the infection poses no problem, prophylactic application of antibiotic remains controversial in the absence of symptoms of infection, but where contrast-enhanced CT scan clearly proves necrosis. This article discusses the present state of the art of the role of antibiotic prophylaxis in the treatment of acute pancreatitis and provides clinical guidelines.

Penetration of antibiotics into the pancreas in rats: an effect of acute necrotizing pancreatitis

BACKGROUND

Penetration of antibiotics into the pancreas is considered to be an important criterion in determining the most appropriate antibiotic treatment during severe acute pancreatitis. Our study investigated pancreatic penetration of five antibiotics in rats with and without acute necrotizing pancreatitis (ANP) (non-pancreatitis rats (NR), pancreatitis rats (AP)).

METHODS

ANP was induced by intraductal bile acid injection, and 3 h later the antibiotic was administered. In both NR and AP the antibiotic concentrations were evaluated in blood and pancreatic tissue 90 min after antibiotic administration.

RESULTS

The tissue/serum (T/S) ratios for NR were 16% with amikacin, 24% with amoxycillin/clavulanic acid, 27% with piperacillin, 59% with ofloxacin, and 108% with cefoperazone. The ratios for AP were 7%, 23%, 26%, 52%, and 70%, respectively. T/S ratios were similar for NR and AP except for amikacin, for which the T/S ratio was lower in AP than in NR (P = 0.02). Pancreatic tissue concentrations of antibiotics with high penetration rates (cefoperazone and ofloxacin) were sufficient to inhibit most of the pathogens expected during acute pancreatitis. The concentrations of the other antibiotics were less than the minimal inhibitory concentrations (MIC) for common potential pathogens in pancreatic infection.

CONCLUSIONS

Cefoperazone and ofloxacin showed the best pancreatic penetration of the five antibiotics tested. The high concentrations of these antibiotics in the pancreatic tissue would have enabled efficient antibacterial activity against most of the potential pathogens causing pancreatic infection. An early stage of acute necrotizing pancreatitis did not have a major effect on the pancreatic concentrations of the antibiotics.

Antibiotic prophylaxis in the initial management of severe acute pancreatitis

BACKGROUND

The role of antibiotic prophylaxis in the initial management of patients with acute pancreatitis is an area of major controversy. Contrary to earlier clinical trials, recent experimental and clinical studies have accrued evidence that warrants reappraisal of current clinical practice. This article reviews these recent advances in knowledge.

METHODS

All papers derived from a Medline search for the years 1990-1997 inclusive using the text words 'acute', 'pancreatitis', 'antibiotic' and 'antibiotics' were studied. Additional papers were derived from reference lists within papers identified by the Medline search. Only experimental and clinical papers relevant to the issue of prophylactic antibiotic therapy in acute pancreatitis are included in the review.

RESULTS AND CONCLUSION

Current experimental evidence favours the use of prophylactic antibiotics in severe acute pancreatitis. The results of contemporary randomized clinical trials restricted to patients with prognostically severe acute pancreatitis have demonstrated improvement in outcome associated with antibiotic treatment.

Immune function early in acute pancreatitis

Circulating lymphocyte numbers and activation together with granulocyte function were measured in 20 patients in the early stages of an attack of acute pancreatitis and in 20 healthy controls. Circulating lymphocytes, T lymphocytes, and CD4 and CD8 T lymphocyte subsets were decreased in both mild pancreatitis (67-80 per cent of controls) and severe pancreatitis (22-40 per cent of controls). CD4:CD8 ratios were unchanged and median (interquartile range) interleukin 2 receptor expression was increased from less than 1 per cent in controls to 14(6) per cent in severe pancreatitis, suggesting lymphocyte activation. Median granulocyte chemiluminescence was increased to 293 per cent of controls in severe pancreatitis and random motility was reduced to 77 per cent of controls, indicating increased metabolic activity. Complement-mediated antibody-independent opsonization and chemotaxis toward endotoxin were normal. Immune function is not reduced early in acute pancreatitis. Granulocyte hyperactivity may be important in the development of multiple organ failure.

Experimental models of acute pancreatitis and their relevance to human disease

There are no experimental models which mimic the most common causes of human acute pancreatitis, i.e. gallstones and alcohol abuse. However, existing models can reproduce the morphology and physiological derangements of certain phases of the illness. Current models have been useful in elucidating the earliest events involved in the initiation and progression of pancreatitis. However, very few animal studies demonstrate effective therapeutic intervention when treatment is given after the induction of experimental pancreatitis. Since immediate intervention is unachievable in human disease, most experimental therapies have not been successfully applied to clinical disease.