Enteroaggregative Escherichia coli as etiological agent of endemic diarrhea in Spain: A prospective multicenter prevalence study with molecular characterization of isolates

Background

Enteroaggregative Escherichia coli (EAEC) is increasingly associated with domestically acquired diarrheal episodes in high-income countries, particularly among children. However, its specific role in endemic diarrhea in this setting remains under-recognized and information on molecular characteristics of such EAEC strains is limited. We aimed to investigate the occurrence of EAEC in patients with non-travel related diarrhea in Spain and molecularly characterize EAEC strains associated with illness acquired in this high-income setting.

Methods

In a prospective multicenter study, stool samples from diarrheal patients with no history of recent travel abroad (n = 1,769) were collected and processed for detection of EAEC and other diarrheagenic E. coli (DEC) pathotypes by PCR. An additional case–control study was conducted among children ≤5 years old. Whole-genome sequences (WGS) of the resulting EAEC isolates were obtained.

Results

Detection of DEC in the study population. DEC was detected in 23.2% of patients aged from 0 to 102 years, with EAEC being one of the most prevalent pathotypes (7.8%) and found in significantly more patients ≤5 years old (9.8% vs. 3.4%, p < 0.001). Although not statistically significant, EAEC was more frequent in cases than in controls. WGS-derived characterization of EAEC isolates. Sequence type (ST) 34, ST200, ST40, and ST10 were the predominant STs. O126:H27, O111:H21, and O92:H33 were the predominant serogenotypes. Evidence of a known variant of aggregative adherence fimbriae (AAF) was found in 89.2% of isolates, with AAF/V being the most frequent. Ten percent of isolates were additionally classified as presumptive extraintestinal pathogenic E. coli (ExPEC), uropathogenic E. coli (UPEC), or both, and belonged to clonal lineages that could be specifically associated with extraintestinal infections.

Conclusion

EAEC was the only bacterial enteric pathogen detected in a significant proportion of cases of endemic diarrhea in Spain, especially in children ≤5 years old. In particular, O126:H27-ST200, O111:H21-ST40, and O92:H33-ST34 were the most important subtypes, with all of them infecting both patients and asymptomatic individuals. Apart from this role as an enteric pathogen, a subset of these domestically acquired EAEC strains revealed an additional urinary/systemic pathogenic potential.

Effective definition of low humoral response to Clostridioides difficile infection

BACKGROUND

Determination of the humoral response to Clostridioides difficile (CD) toxins could be of great value in the management of patients with CD infection (CDI).

METHODS

A prospective study was conducted on the clinical characteristics and humoral response in patients with CDI. Determination of ELISA IgG CD anti-toxin B (tgcBiomics, Germany) was performed. The following dilutions were planned for each patient, 1:100, 1: 200, 1: 400, 1: 800: 1: 1600. A significant concentration of antibody was considered to be present in each dilution if an optical density 0.2 units higher than the negative control of the technique was evident.

RESULTS

Eighty-five patients were included during the study period, November 2018-February 2020. The median age was 73 years (interquartile range: 62.5-85 years), with female predominance (45 patients, 52.9%). Thirty-nine patients (45.9%) had a severe infection. Seven patients (8.2%) had suffered an episode of CDI in the previous three months. Seventeen patients (20%) had one or more recurrent episodes during the three-month follow-up: No patient died during admission or required surgery for severe-complicated infection. The incidence of recurrence in patients with no antibody detected at 1:400 dilution was 25.4% (16 patients) while it was 4.3% (one patient) in patients with antibody present at that dilution (p = 0.03). Liver cirrhosis was associated with higher humoral response against CD.

CONCLUSIONS

Antibodies IgG CD anti-toxin B detection at a dilution of 1:400, using a B ELISA technique, effectively identified patients at increased risk of recurrence. This information could help assist in the management of patients.

Risk Factors for Clostridioides Difficile Diarrhea In Solid Organ Transplantation Recipients

BACKGROUND

There is limited knowledge about risk factors for Clostridioides difficile infection (CDI) and recurrent CDI in solid organ transplant (SOT) recipients.

METHODS

A case-control study of CDI in SOT recipients compared with controls (SOT recipients who did not present CDI).

RESULTS

Sixty-seven patients from 1089 SOT recipients (6.2%) suffered at least one episode of CDI. The mean age was 55 ± 12 years and 20 cases (69%) were men. The accumulated incidence was 8% in liver transplantation, 6.2% in lung transplantation, 5.4% in heart transplantation, and 4.7% in kidney transplantation. Twenty-nine cases (43.3%) were diagnosed during the first 3 months after SOT. Forty-one cases (61.2%) were hospital acquired. Thirty-one patients with CDI presented with mild-moderate infection (46.3%), 30 patients with severe infection (44.8%), and 6 patients with severe-complicated disease (9%). Independent variables found to be related with CDI were hospitalization in the previous 3 months (odds ratio: 2.99; [95% confidence interval 1.21-7.37]) and the use of quinolones in the previous month (odds ratio: 3.71 [95% confidence interval 1.16-11.8]). Eleven patients (16.4%) had at least one recurrence of CDI. Previous treatment with amoxicillin-clavulanate, severe-complicated index episode, and high serum creatinine were associated with recurrent CDI in the univariant analysis CONCLUSIONS: Liver transplant recipients presented the highest incidence of CDI among SOT recipients. Risk factors for CDI were hospitalization in the previous 3 months and the use of quinolones in the previous month.

Risk Factors for Clostridium Difficile Diarrhea in Patients With Solid Organ Transplantation

BACKGROUND

There is limited knowledge about specific risk factors for Clostridium difficile infection (CDI).

METHOD

A retrospective study comparing cases of CDI in solid organ transplant (SOT) recipients with controls (SOT recipients who did not present CDI).

RESULTS

Thirty patients with SOT from 1340 transplantation recipients had at least 1 episode of CDI (2.23%). The accumulated incidence was 3.06% in liver transplantation, 2.78% in lung transplantation, 2.36% in kidney transplantation, and 0.33% in heart transplantation. Seven (23%) cases occurred during the first 2 months. Fifteen (50%) cases were community acquired. Colonoscopy was performed in 6 (20%) cases, but pseudomembranes were observed in only 1 (16%) case. Independent variables found to be related to CDI were previous treatment with proton pump inhibitors (PPIs; odds ratio [OR] 5.5; 95% confidence interval [CI] 1.2-32.0), immunosuppressive regimen including mycophenolate (OR 5.2; 95%CI 1.1-18), hospitalization during the previous 3 months (OR 5.1; 95%CI 1.1-17), and antibiotic treatment during the previous month (OR 6.7; 95%CI 1.4-23). Five (16.7%) patients did not respond to the initial treatment. Recurrences were noted in 6 (20%) patients.

CONCLUSIONS

Liver transplant recipients presented the highest incidence. Risk factors for CDI were previous treatment with PPIs, immunosuppressive regimen containing mycophenolate, prior hospitalization, and prior antibiotic treatment.

Molecular Genotyping of Giardia duodenalis Isolates from Symptomatic Individuals Attending Two Major Public Hospitals in Madrid, Spain

BACKGROUND

The flagellate protozoan Giardia duodenalis is an enteric parasite causing human giardiasis, a major gastrointestinal disease of global distribution affecting both developing and industrialised countries. In Spain, sporadic cases of giardiasis have been regularly identified, particularly in pediatric and immigrant populations. However, there is limited information on the genetic variability of circulating G. duodenalis isolates in the country.

METHODS

In this longitudinal molecular epidemiological study we report the diversity and frequency of the G. duodenalis assemblages and sub-assemblages identified in 199 stool samples collected from 184 individual with symptoms compatible with giardiasis presenting to two major public hospitals in Madrid for the period December 2013-January 2015. G. duodenalis cysts were initially detected by conventional microscopy and/or immunochomatography on stool samples. Confirmation of the infection was performed by direct immunofluorescence and real-time PCR methods. G. duodenalis assemblages and sub-assemblages were determined by multi-locus genotyping of the glutamate dehydrogenase (GDH) and β-giardin (BG) genes of the parasite. Sociodemographic and clinical features of patients infected with G. duodenalis were also analysed.

PRINCIPAL FINDINGS

Of 188 confirmed positive samples from 178 giardiasis cases a total of 124 G. duodenalis isolates were successfully typed at the GDH and/or the BG loci, revealing the presence of sub-assemblages BIV (62.1%), AII (15.3%), BIII (4.0%), AI (0.8%), and AIII (0.8%). Additionally, 6.5% of the isolates were only characterised at the assemblage level, being all of them assigned to assemblage B. Discordant genotype results AII/AIII or BIII/BIV were also observed in 10.5% of DNA isolates. A large number of multi-locus genotypes were identified in G. duodenalis assemblage B, but not assemblage A, isolates at both the GDH and BG loci, confirming the high degree of genetic variability observed in other molecular surveys. BIV was the most prevalent genetic variant of G. duodenalis found in individuals with symptomatic giardiasis in the population under study.

CONCLUSIONS

Human giardiasis is an ongoing public health problem in Spain affecting primarily young children under four years of age but also individuals of all age groups. Our typing and sub-typing results demonstrate that assemblage B is the most prevalent G. duodenalis assemblage circulating in patients with clinical giardiasis in Central Spain. Our analyses also revealed a large genetic variability in assemblage B (but not assemblage A) isolates of the parasite, corroborating the information obtained in similar studies in other geographical regions. We believe that molecular data presented here provide epidemiological evidence at the population level in support of the existence of genetic exchange within assemblages of G. duodenalis.

Molecular genotyping and sub-genotyping of Cryptosporidium spp. isolates from symptomatic individuals attending two major public hospitals in Madrid, Spain

Infections by members of the protozoan genus Cryptosporidium are among the most common causes of human gastrointestinal illness worldwide. In Spain cryptosporidiosis is not a compulsory notifiable disease, so the actual burden of the infection in both clinical and general populations remains largely unknown. We present here data on the diversity and frequency of the Cryptosporidium species and sub-genotypes identified in symptomatic individuals seeking medical care in two major hospitals in Madrid, Spain, between December 2013 and January 2015. Initial detection of the parasite was conducted on a total of 122 stool samples collected from 120 patients by microscopy with modified Ziehl-Neelsen and/or immunochromatographic tests. We used immunofluorescence, PCR-based methods and sequence analyses of the 60-kDa (GP60) glycoprotein and the small subunit ribosomal RNA (SSU rRNA) genes for confirmatory purposes and to characterize Cryptosporidium isolates. A total of 110 patients were confirmed with cryptosporidiosis. Overall, 101 isolates were successfully sub-genotyped at the GP60 locus, and an additional seven at the SSU rRNA locus. The analyses of all amplicons defined 10 distinct sequence types representing the GP60 family sub-genotypes IbA10G2 (78.7%), IeA11G3T3 (3.7%) of C. hominis, and the GP60 family sub-types IIaA15G2R1 (5.6%), IIaA18G6R1 (0.9%), IIcA5G3a (0.9%), IIdA18G1 (0.9%), IIdA19G1 (0.9%), IIdA21G1 (0.9%), and IIdA22G1 (0.9%) of C. parvum. A single isolate was assigned to C. felis (0.9%), two C. parvum isolates (1.9%) could not be characterized at the sub-genotype level and an additional four isolates (3.7%) were not typable. These results strongly suggest that transmission of cryptosporidiosis is mostly anthroponotic in origin in the clinical sample under study. We expect that our molecular epidemiological data will make a significant contribution to unravel the actual epidemiological situation of cryptosporidiosis in Spain, providing health care and policy makers with solid baseline information to unavoidably improve the national surveillance system and allocate additional resources to research, diagnosis, and treatment of cryptosporidiosis.

Risk factors for Clostridium difficile diarrhea in patients with inflammatory bowel disease

BACKGROUND

Despite the growing incidence of Clostridium difficile diarrhea (CCD) in patients with inflammatory bowel disease (IBD), little is known about the associated risk factors.

METHOD

A retrospective study comparing cases of CCD in patients with IBD to IBD carriers who did not develop CCD. A comparison was also made with patients who developed CCD but did not suffer IBD.

RESULTS

Three cases (20%) with IBD and CCD had received antibiotics during the previous three months versus none of the controls (IBD without CCD, p = 0.22). Ten cases (67%) received treatment with proton pump inhibitors (PPIs) versus 2 (13%) in the control group (IBD without CCD, p = 0.001). Seven cases underwent colonoscopy and pseudomembranes were seen in one (14%). Fourteen (93%) patients demonstrated a favourable response to metronidazole. Patients with IBD and CCD presented with younger age (36 ± 10 years), a higher degree of community-acquired infection (13 patients, 87%), immunosuppressive treatment (7 patients, 47%) and less patients had received previous antibiotic treatment (3 patients, 20%) than those with CCD without IBD. The proportion of patients who received treatment with PPIs was similar (66% and 80%, respectively p = 0.266).

CONCLUSIONS

CCD in IBD carriers affects younger patients, the majority are community acquired (less nosocomial) and it is more related to previous treatment with PPIs than with the antibiotic treatment. Clinical evolution is also favourable.

[Control of Chagas disease in pregnant Latin-American women and her children]

Chagas disease is a chronic and systemic infection caused by Trypanosoma cruzi. According to estimates from WHO, 10 million people are affected by this parasite. In the last years, birthrate among the immigrant women from Latin America settled in the Comunidad Autónoma de Madrid has been increasing, and as T. cruzi can be transmitted from mother to child, in fact 11 cases of congenital Chagas disease have been confirmed. Therefore, the aim of this paper is encouraging improvements in the coverage of the anti-T. cruzi antibodies detection in pregnant women from endemic areas. By this strategy, an active search for infected pregnant women and early detection of her infected newborns could be conducted, and then an early specific treatment could be administrated. Thus, there could be an important contribution to the control of Chagas disease in non-endemic area.

Application of real-time PCR for the differentiation of Entamoeba histolytica and E. dispar in cyst-positive faecal samples from 130 immigrants living in Spain

In an effort to improve the diagnosis of intestinal amoebiasis, a real-time PCR has been used for the detection and differentiation of Entamoeba histolytica and E. dispar infections in African or South American immigrants who live in Spain. Faecal samples from all of the 130 subjects had apparently been found to contain E. histolytica/E. dispar cysts by microscopical examination. Using the real-time PCR, E. histolytica DNA was detected in faecal samples from only 10 (7.7%) of the immigrants, with E. dispar DNA detected in the samples from another 117 (90.0%) of the subjects. The use of such PCR in the routine investigation of patients found positive for E. histolytica/E. dispar cysts (by microscopy) is recommended, especially in non-endemic areas.

CTX-M-15-producing urinary Escherichia coli O25b-ST131-phylogroup B2 has acquired resistance to fosfomycin

OBJECTIVES

To describe trends in fosfomycin resistance in urinary isolates of Escherichia coli producing extended-spectrum beta-lactamases (ESBLs) in relation to fosfomycin consumption and to characterize representative fosfomycin-resistant isolates.

METHODS

In 2007-08, an unexpected increase in fosfomycin resistance in ESBL-producing urinary E. coli was observed. Laboratory records were reviewed and a prospective surveillance study was initiated on all urinary tract infections caused by ESBL-producing, fosfomycin-resistant E. coli. bla(ESBL) types, phylogroups, genetic environment and afa/dra operon were determined by PCR and sequencing. Molecular epidemiology was analysed by PFGE and multilocus sequence typing. To elucidate possible mechanisms of fosfomycin resistance, uhpT, glpT, uhpA, ptsI, cyaA and murA genes were analysed. Fosfomycin consumption was determined as recommended by WHO.

RESULTS

From 2004 to 2008, fosfomycin consumption increased by 50%, while fosfomycin resistance in ESBL producers increased from 2.2% to 21.7%. Of 26 isolates studied, 24 produced CTX-M-15 and belonged to the O25b-ST131-phylogroup B2 clonal strain. PFGE revealed two clusters. Cluster I included 18 isolates, 16 of them indistinguishable from strains producing CTX-M-15 previously described in Madrid. The five isolates of Cluster II had the IS26 linked to bla(CTX-M-15) and the afa/dra operon. In Cluster I isolates, no mutations in glpT, uhpT, uhpA, ptsI, cyaA and murA were detected. Cluster II isolates showed a 15 bp deletion (A(169)-C(183)) in uhpA.

CONCLUSIONS

Fosfomycin resistance in urinary E. coli has increased due to the acquisition of this resistance by a previously circulating CTX-M-15-producing E. coli O25b-ST131-phylogroup B2 strain. This happened during a period when the use of fosfomycin increased by 50%.

[What are we learning about Staphylococcus saprophyticus?]

INTRODUCTION

Staphylococcus saprophyticus is frequent cause of urinary tract infection in women; hence, it is important to know the epidemiology and antibiotic susceptibility of this microorganism.

METHOD

A retrospective longitudinal study was performed in urine specimens from outpatients in our health area cultured in the Microbiology Laboratory of C.E. Argüelles (Madrid, Spain) over a 10-year period (1997-2006).

RESULTS

Among 35,136 urine cultures with a significant count, we identified 331 S. saprophyticus (0.9%); 324 in women and 7 in men. Mean age of the infected patients was 32.7 years. A total of 83.9% of the strains were in women aged 15 to 44 years (37 women in this group were pregnant) and the largest numbers of isolates were found during the months of June and November. All S. saprophyticus strains were susceptible to vancomycin, rifampin, gentamicin and amoxicillin-clavulanic acid. Of note, there was a high percentage of resistance to erythromycin (37.7%) (96% consistent with the MSB phenotype) which has significantly increased since 1997 (P < 0.05); 1.5% were also resistant to clindamycin. Only 0.9% were resistant to fluorquinolones. Resistance to chloramphenicol, trimethoprim/sulfamethoxazole, and penicillin was 3.9%, 6%, and 55.6%, respectively. Based on the 2006 CLSI guidelines, 45% of S. saprophyticus isolates were considered oxacillin-resistant.

CONCLUSION

These results suggest the following: First, S. saprophyticus should be considered among agents causing urinary tract infection in women 15 to 44 years old, including pregnant women, particularly during spring and autumn. Second, cotrimoxazole may be an excellent option for treating cystitis in patients without risk factors. Third, almost half of S. saprophyticus strains were considered oxacillin-resistant, thereby denying the benefit of treatment with oral beta-lactams in urinary tract infections. This is especially important in pregnant women, who should avoid trimethoprim/sulfamethoxazole and quinolones (FDA Group C), as well as fosfomycin, with in vitro resistance.

[Haemophilus spp. antimicrobial susceptibility in Health Area 6 in Madrid, Spain (2000-2004)]

The aim of this study was to assess the antimicrobial susceptibility of 1370 Haemophilus spp. (1051 H. influenzae and 319 H. parainfluenzae) isolated during a 4-year period (July 2000 to June 2004) and to compare the results with other nationwide Spanish surveillance studies. The rate of isolation of H. parainfluenzae was significantly higher in clinical samples from the genitourinary tract (p <0.00001) and skin and soft tissues (p <0.00001), whereas H. influenzae was significantly more frequent in clinical respiratory tract samples (p <0.00001). A total of 46.2% and 31.8% of H. influenzae were isolated in infants and children of 2-6 years old, respectively; whereas 73.3% of H. parainfluenzae was isolated in patients older than age 14. Overall, 22.2% and 18.5% of the H. influenzae and H. parainfluenzae, respectively, were found to produce betalactamase. A total of 1.9% of betalactamase-negative H. influenzae were found to be resistant to ampicillin. Four strains (0.4%) of betalactamase-producing H. influenzae were resistant to amoxicillin-clavulanic acid, all isolated from infants. The rate of ampicillin susceptibility was significantly higher (p <0.01) in H. parainfluenzae than in H. influenzae. All of the 1370 strains of Haemophilus spp. were susceptible to cefotaxime and ciprofloxacin. The susceptibility to clarithromycin, trimethoprim-sulfamethoxazole, tetracycline, chloramphenicol and rifampin were 86.9%, 61.5%, 96.7%, 99.1% and 95.2% for H. influenzae versus 81.2%, 55.8%, 76.5%, 90,9% and 733% for H. parainfluenzae. In conclusion, H. influenzae is more resistant to ampicillin and H. parainfluenzae to non-betalactam antimicrobials. All isolates were susceptible to cefotaxime and ciprofloxacin.

Effects of hypothermic perfusion on pulmonary circulation in isolated rabbit lung

The effects of hypothermic perfusion have been studied by using different perfusates in 24 isolated rabbit lung preparations, divided into three groups: G1, perfused with blood (hematocrit of 10%) and G2 and G3, perfused with erythrocyte-free plasma plus 6% protein in saline. In both G1 and G2 groups left atrial pressures were kept below airway pressure (Zone II conditions), and in G3 it was higher than airway pressure (Zone III conditions). Perfusate flow, pulmonary artery pressure, pulmonary vascular resistance, left atrial pressure, fluid filtration rate, colloid osmotic pressure and temperature were not different (p > 0.1) between G1 and G2 at the beginning of the experiments. Lowering perfusate temperature from 38 degrees C to 28 degrees C produced a significant increase in pulmonary artery pressure and pulmonary vascular resistance in G1 but they decreased in G2 lungs (p < 0.05). Fluid filtration rate increased in both groups during hypothermia. These responses were not inhibited by an alpha-adrenergic receptor blocker or a pulmonary vasodilator. In G3 lungs no changes were observed. The differences in the hemodynamic effects of hypothermia observed in G1 and G2, both in Zone II conditions, could result from the differences in the vessel distention state obtained by each of the perfusate before initiating hypothermia. As perfusate viscosity increase with cold, a greater possibility of vessel distention in G2 lungs occurs. This explains the decrease in pulmonary artery pressure and pulmonary vascular resistance with cold in this group. The increase in fluid filtration rate observed with hypothermia in G1 and G2 may be due to increases in fluid exchange area.

[Effect of the administration of intralipid on liquid filtration rate and pressure of the pulmonary artery in isolated lung of rabbits]

INTRODUCTION

We study the effect on Intralipid on pulmonary circulation.

METHODS

A 10% infusion of Intralipid was administered at a dose of 0.5/kg in 14 isolated rabbit lungs in which constant blood flow infusion was carried out principally in zone 3. The liquid filtration rate (LFR) and the mean pressure of the pulmonary artery were measured.

RESULTS

A constant increase of mean pressure of the pulmonary artery was observed following the infusion (from 12.32 +/- 3.66 cm of H2O to 39.92 +/- 07.68 cmH2O (p < 0.01) which was associated to a significant increase in the rate of liquid filtration (from 0.018 +/- 0.01 g/min to 0.198 +/- 0.04 g/min; p < 0.01).

CONCLUSIONS

The administration of Intralipid produces a statistically significant increase of mean pressure of the pulmonary artery and the rate of liquid filtration. This is probably caused by vasoconstriction due to metabolic changes produced by Intralipid on pulmonary circulation.