A model of acute infectious neonatal diarrhoea

Oral inoculation of neonatal MFI mice with enterotoxigenic strains of Escherichia coli that possessed the K99 or F41 antigen or both resulted in severe diarrhoea with high mortality. The diarrhoea was associated with increased fluid in the gut, greatly increased numbers of E. coli in gut homogenates and reduced weight gain compared to control animals. Further studies with strain B44 demonstrated greatly increased numbers of E. coli on the surface of the intestinal mucosa and haemo-concentration. The infection was transmissible between litter-mates. There was no evidence of invasion of the intestinal tissue of infected animals. Gnotobiotic Balb C mice and endotoxin-resistant mice were susceptible to oral inoculation with bovine enterotoxigenic E. coli strains, but neonatal rats were not susceptible to infection with enterotoxigenic E. coli strains B44 or 431. Porcine strains of E. coli that possessed K88 or 987P antigen did not infect neonatal MFI mice but an "atypical" porcine strain (431) which possessed both K99 and F41 antigens caused diarrhoea and a high mortality. The disease in neonatal mice resembled acute diarrhoea caused by these bacteria in other species, particularly the calf, and the model should be of value in assessing the efficacy of therapeutic agents.     

Yersinia enterocolitica associated diarrhoea in a neonate

European Journal of Clinical Microbiology &; Infectious Diseases -     

Pseudothrombocytopenia associated with infectious mononucleosis

A 22-year-old man was hospitalized for assessment of thrombocytopenia and fever. Examination showed that he had infectious mononucleosis and moderately severe thrombocytopenia that was asymptomatic. Examination of blood smears revealed that the thrombocytopenia was caused by the clumping of platelets. We made a diagnosis of ethylenediaminetetraacetic acid-dependent pseudothrombocytopenia after excluding other infectious mononucleosis-related mechanisms of thrombocytopenia. When the patient recovered from infectious mononucleosis 2 months later, his thrombocytopenia improved, and no platelet clumping in peripheral blood smears was noted. Ethylenediaminetetraacetic acid-dependent pseudothrombocytopenia should always be considered as a possible cause of reported low platelet counts, even in patients with infectious mononucleosis and splenomegaly.     

Hepatic granulomas, with an emphasis on infectious causes

Granulomas are aggregates of macrophages, often admixed with other inflammatory cells, which usually result from chronic antigen presentation. Many diseases that produce granulomas involve the liver. Some are intrinsic hepatic diseases, whereas others are disseminated systemic diseases that involve the liver and other organs. Hepatic granulomas are reportedly present in 2% to 10% of all liver biopsy specimens examined in general practice, and of those supposedly as many as 36% have no discoverable etiology even after extensive evaluation of the specimen. This review focuses on the diagnosis of granulomas in infectious diseases affecting the liver, including use of special stains, serologic studies, and molecular diagnostic techniques, and discusses pertinent noninfectious causes of hepatic granulomas that are in the differential diagnosis.     

Cold urticaria associated with infectious mononucleosis

We have evaluated two patients with cold urticaria associated with infectious mononucleosis and reviewed three case reports with this syndrome. The cold sensitivity ranged from urticaria to anaphylaxis and one patient had additional cold-related cutaneous manifestations. The duration of cold urticaria was transient and paralleled the clinical course of infectious mononucleosis. Analysis of these five cases revealed no correlation of cold urticaria with known cold-activated factors that often occur in this viral infection.     

Some infectious causes of diarrhea in young farm animals.

Escherichia coli, rotaviruses, and Cryptosporidium parvum are discussed in this review as they relate to enteric disease in calves, lambs, and pigs. These microorganisms are frequently incriminated as causative agents in diarrheas among neonatal food animals, and in some cases different strains or serotypes of the same organism cause diarrhea in humans. E. coli causes diarrhea by mechanisms that include production of heat-labile or heat-stable enterotoxins and synthesis of potent cytotoxins, and some strains cause diarrhea by yet undetermined mechanisms. Rotaviruses and C. parvum induce various degrees of villous atrophy. Rotaviruses infect and replicate within the cytoplasm of enterocytes, whereas C. parvum resides in an intracellular, extracytoplasmic location. E. coli, rotavirus, and C. parvum infections are of concern to producers, veterinarians, and public health officials. These agents are a major cause of economic loss to the producer because of costs associated with therapy, reduced performance, and high morbidity and mortality rates. Moreover, diarrheic animals may harbor, incubate, and act as a source to healthy animals and humans of some of these agents.     

Human rotavirus subgroups and severity of associated diarrhoea in Ghana

In a 12 month study of children with acute diarrhoea seeking medical care in 2 hospitals in Accra, Ghana, 16.3% were found to be infected with human rotaviruses (HRV). Vomiting and diarrhoea were the main symptoms observed. HRV infection was frequently associated with severe diarrhoea. Vomiting was however less frequent in HRV associated diarrhoea than in non HRV diarrhoea. No significant association was observed between the severity of dehydration and HRV infection. Subgroup II HRV was the predominant subgroup identified with the dominant serotypes being HRV serotypes 1 and 4. Poly-acrylamide gel electrophoresis of HRV RNAs isolated from 40 positive stool samples revealed the existence of 7 distinct electrophoretic migration patterns in the study population.     

Antibiotic treatment and associated prolonged prothrombin time.

The incidence and type of pathology causing a prolonged prothrombin time and clinical bleeding episodes were assessed in a multicentre study of 1109 patients receiving cefotetan, a N-methyl-thiotetrazole (NMTT), or equivalent antibiotics. There was no significant difference in the incidence of a prolonged prothrombin time (9.9% with cefotetan, 8.0% with comparable antibiotics) of clinical bleeding episodes. However, prothrombin time increases of greater than 12 seconds were significantly (p = 0.002) greater with cefotetan (3.8%) than with comparators (0.8%). In both antibiotic groups increases in prothrombin time were more likely following surgery and in patients who were older, with a high platelet count, low albumin, or higher urea and creatinine concentrations. All antibiotic treatment can be associated with prolonged prothrombin times and new agents should always be assessed in a large multicentre study before the practical, clinical importance of haemostatic defects can be defined.     

Simple objective criteria for diagnosis of causes of acute diarrhoea on rectal biopsy.

AIM: To identify simple, objective, accurate histological criteria for distinguishing acute infective-type colitis, chronic idiopathic inflammatory bowel disease, and irritable bowel syndrome on rectal biopsy in patients with acute onset diarrhoea at first presentation, one to 10 weeks after onset. METHODS: Cell counts and measurements of mucosal architecture were made on initial rectal biopsies from 18 patients with acute infective-type colitis, 17 patients with first acute presentation of chronic idiopathic inflammatory bowel disease, and 23 patients with irritable bowel syndrome. The data were analysed by ANOVA and discriminant analysis. RESULTS: Lamina propria cells were mainly in the upper third in irritable bowel syndrome patients. Increased lamina propria cellularity, mainly in the middle third, and numbers of crypt intraepithelial neutrophils distinguished acute infective-type colitis from irritable bowel syndrome in 93% of cases. Chronic idiopathic inflammatory bowel disease differed from irritable bowel syndrome and acute infective-type colitis in a decreased number of crypts and altered crypt architecture. Chronic idiopathic inflammatory bowel disease showed higher lamina propria cellularity, especially in the basal third, with an increased number of lamina propria neutrophils. On discriminant analysis, crypt numbers distinguished 86% of the cases of chronic idiopathic inflammatory bowel disease from the other groups. CONCLUSION: At one week or more from onset, acute infective-type colitis is characterised by a superficial increase in lamina propria cellularity, with only a slight increase in the number of polymorphs. At this stage, chronic idiopathic inflammatory bowel disease is characterised by a transmucosal increase in cellularity together with crypt loss and architectural abnormality. Thus, measurement of mucosal architecture establishes simple, accurate, objective criteria for routine biopsy diagnosis of chronic idiopathic inflammatory bowel disease from acute infective-type colitis and irritable bowel syndrome at initial presentation, one to 10 weeks after onset.     

Organ-specific immune responses associated with infectious disease

The immune response to infection can vary markedly in different organs of the same animal. In some organs, the infection can resolve with subsequent immunity to re-infection, whereas in other organs, pathogens can persist. Here, Christian Engwerda and Paul Kaye highlight the importance of defining organ-specific immune mechanisms for developing strategies that deal effectively with infectious diseases and their associated pathologies.     

The utility of multiplex polymerase chain reaction for diagnosis of infectious diarrhoea in a tropical country

PurposeThe etiology of infective diarrheaoften remains undiagnosed. We studied the role of multiplex polymerase chain reaction (PCR) for detection of etiological agents of diarrhoea.MethodsFast track diagnostics (FTD)gastroenteritis panel for bacterial and viral pathogens was used to test stool samples from patients with diarrhoea.ResultsStool samples from 276 patients (138 immunocompetent and 138 immunocompromised) with diarrhoea and 138 healthy controls were tested. Bacterial culture was positive in 5 samples. Following agents were isolated: Shigella sonnei(2), Shigella dysentriae(1), SalmonellaParatyphi B(1) and Vibrio cholerae (1). Multiplex PCR panel did not include Vibrio cholerae in its panel. A total of 65 target pathogens were identified in 60/276 (21.7%) patients by multiplex PCR. 28/65(41.1%) and 37/65 (56.9%) were bacterial and viral agents respectively. Identified bacteria were Shigella(20), Salmonella(3), Campylobacter(4) and Clostridium difficile(1). Viral targets identified were Norovirus GII (28), Adenovirus(4), Astrovirus(3) and Sapovirus(2). All the controls were negative for enteropathogens by conventional methods and multiplex PCR.ConclusionsOur detection rates increased from 1.8% (5/276)by conventional methods to 21.7% (60/276)by multiplex PCR, which included both bacterial as well as viral targets.     

Enterotoxigenic Escherichia coli associated with infant diarrhoea in Galicia, north-western Spain

To assess the role of enterotoxigenic Escherichia coli (ETEC) in infantile diarrhoea, 482 children with diarrhoea and 103 healthy controls, from three localities of Galicia, north-western Spain, were investigated between 1985 and 1988. Rotavirus (37.3%) and Salmonella spp. (12.8%) were the most common causal agents, followed by ETEC (3.9%), Campylobacter jejuni (2.3%), Shigella spp. (0.9%) and Yersinia enterocolitica (0.5%). ETEC were significantly more frequently isolated from children with diarrhoea who were under 1 month of age (26.5%) than from older diarrhoeic children (2.2%) (p less than 0.001) or from healthy children who were under 1 month of age (0%) (p less than 0.05). Among children who harboured ETEC, five of the nine children under 1 month of age developed diarrhoea in hospital, whereas none of the 10 children over 1 month of age did so. Seventeen ETEC isolates produced heat-stable enterotoxin (STa) only, four produced only heat-labile enterotoxin (LT), and two produced both toxins. Colonisation factor antigens CFA/I and CFA/II were detected in 11 (55.0%) of the 20 ETEC isolates that remained enterotoxigenic after maintenance in the laboratory. Most ETEC isolates belonged to serotypes O153:K-:H45 (nine STa+ CFA/I+ isolates), O27:K-:H7 (three STa+ isolates) or O6:K15:H16 (two LT+ STa+ CFA/II+ isolates). Our results suggest that ETEC constitute an important cause of neonatal diarrhoea in this part of Spain.     

Susceptibility patterns of enteroaggregative Escherichia coli associated with traveller's diarrhoea: emergence of quinolone resistance.

Enteroaggregative Escherichia coli (EAggEC) isolates were identified as a cause of traveller's diarrhoea in 50 (9%) of 517 patients and their antimicrobial susceptibility was determined. Molecular epidemiological characterisation and investigation of the mechanisms of acquisition of quinolone resistance among nalidixic acid-resistant EAggEC strains was performed. Seventeen (34%) of 50 patients needed antimicrobial therapy, because of persistence of symptoms in nine cases and the severity of symptoms in eight cases. Ampicillin and tetracycline resistance was high, whereas chloramphenicol and co-trimoxazole showed moderate activity and amoxicillin plus clavulanic acid, nalidixic acid and ciprofloxacin showed very good activity. Resistance to nalidixic acid was demonstrated in three isolates, two from patients who had travelled to India. In all three strains the resistance was linked to mutations in the gyrA gene alone or in both gyrA and parC genes. Although ciprofloxacin shows excellent in-vitro activity and could be useful in the treatment of traveller's diarrhoea in patients travelling abroad, it may not be useful in patients who have journeyed to India or to Mexico.     

Antibiotic resistance associated with the COVID-19 pandemic: a systematic review and meta-analysis

BackgroundCOVID-19 and antimicrobial resistance (AMR) are two intersecting global public health crises.ObjectiveWe aimed to describe the impact of the COVID-19 pandemic on AMR across health care settings.Data sourceA search was conducted in December 2021 in WHO COVID-19 Research Database with forward citation searching up to June 2022.Study eligibilityStudies evaluating the impact of COVID-19 on AMR in any population were included and influencing factors were extracted. Reporting of enhanced infection prevention and control and/or antimicrobial stewardship programs was noted.MethodsPooling was done separately for Gram-negative and Gram-positive organisms. Random-effects meta-analysis was performed.ResultsOf 6036 studies screened, 28 were included and 23 provided sufficient data for meta-analysis. The majority of studies focused on hospital settings (n = 25, 89%). The COVID-19 pandemic was not associated with a change in the incidence density (incidence rate ratio 0.99, 95% CI: 0.67–1.47) or proportion (risk ratio 0.91, 95% CI: 0.55–1.49) of methicillin-resistant Staphylococcus aureus or vancomycin-resistant enterococci cases. A non-statistically significant increase was noted for resistant Gram-negative organisms (i.e. extended-spectrum beta-lactamase, carbapenem-resistant Enterobacterales, carbapenem or multi-drug resistant or carbapenem-resistant Pseudomonas aeruginosa or Acinetobacter baumannii, incidence rate ratio 1.64, 95% CI: 0.92–2.92; risk ratio 1.08, 95% CI: 0.91–1.29). The absence of reported enhanced infection prevention and control and/or antimicrobial stewardship programs initiatives was associated with an increase in gram-negative AMR (risk ratio 1.11, 95% CI: 1.03–1.20). However, a test for subgroup differences showed no statistically significant difference between the presence and absence of these initiatives (p 0.40).ConclusionThe COVID-19 pandemic may have hastened the emergence and transmission of AMR, particularly for Gram-negative organisms in hospital settings. But there is considerable heterogeneity in both the AMR metrics used and the rate of resistance reported across studies. These findings reinforce the need for strengthened infection prevention, antimicrobial stewardship, and AMR surveillance in the context of the COVID-19 pandemic.