K-Means Clustering Identifies Diverse Clinical Phenotypes in COVID-19 Patients: Implications for Mortality Risks and Remdesivir Impact

INTRODUCTION

The impact of remdesivir on mortality in patients with COVID-19 is still controversial. We aimed to identify clinical phenotype clusters of COVID-19 hospitalized patients with highest benefit from remdesivir use and validate these findings in an external cohort.

METHODS

We included consecutive patients hospitalized between February 2020 and February 2021 for COVID-19. The derivation cohort comprised subjects admitted to Hospital Clinic of Barcelona. The validation cohort included patients from Hospital Universitari Mutua de Terrassa (Terrassa) and Hospital Universitari La Fe (Valencia), all tertiary centers in Spain. We employed K-means clustering to group patients according to reverse transcription polymerase chain reaction (rRT-PCR) cycle threshold (Ct) values and lymphocyte counts at diagnosis, and pre-test symptom duration. The impact of remdesivir on 60-day mortality in each cluster was assessed.

RESULTS

A total of 1160 patients (median age 66, interquartile range (IQR) 55-78) were included. We identified five clusters, with mortality rates ranging from 0 to 36.7%. Highest mortality rate was observed in the cluster including patients with shorter pre-test symptom duration, lower lymphocyte counts, and lower Ct values at diagnosis. The absence of remdesivir administration was associated with worse outcome in the high-mortality cluster (10.5% vs. 36.7%; p < 0.001), comprising subjects with higher viral loads. These results were validated in an external multicenter cohort of 981 patients.

CONCLUSIONS

Patients with COVID-19 exhibit varying mortality rates across different clinical phenotypes. K-means clustering aids in identifying patients who derive the greatest mortality benefit from remdesivir use.

Host genetic variants associated with susceptibility and severity of pneumococcal pneumonia in adult patients

BACKGROUND

Pneumococcal community-acquired pneumonia (P-CAP) is a major cause of morbidity and hospitalization. Several host genetics factors influencing risk of pneumococcal disease have been identified, with less information about its association with P-CAP. The aim of the study was to assess the influence of single nucleotide polymorphisms (SNP) within key genes involved in the innate immune response on the susceptibility to P-CAP and to study whether these polymorphic variants were associated with the severity and outcome of the episodes in a cohort of adult Caucasian patients.

METHODS

Seventeen SNPs from 7 genes (IL-R1, IL-4, IL-10, IL-12B, NFKBIA, NFKBIE, NFKBIZ) were analyzed. For susceptibility, a case-control study including a cohort of 57 adult with P-CAP, and 280 ethnically matched controls was performed. Genetic influence on clinical severity and outcome was evaluated in a prospective observational study including all consecutive adult P-CAP patients from November 2015 to May 2017.

RESULTS

The NFKBIA polymorphism rs696 and a haplotype combination were associated with susceptibility to P-CAP (OR = 0.62, p = 0.005 and OR = 0.63, p = 0.008, respectively). The SNP IL4 rs2227284 was associated with severe P-CAP (OR = 2.17, p = 0.04). IL-R1 (rs3917267) and IL-10 (rs3024509) variants were related with respiratory failure (OR = 3.31, p = 0.001 and OR = 0.18, p = 0.003, respectively) as well as several haplotype combinations in NFKBIA, NFKBIZ, IL-R1 and IL-10 (p = 0,02, p = 0,01, p = 0,001, p = 0,03, respectively). CURB-65 values were associated with the IL-10 rs3024509 variant (beta = - 0.4, p = 0.04), and with haplotype combinations of NFKBIZ and IL-10 (p = 0.05, p = 0.04, respectively). Genetic variants in IL-10 (rs3024509) and in IL-12B (rs730691) were associated with PSI values (beta = - 0.54, p = 0.01, and beta = - 0.28, p = 0.04, respectively), as were allelic combinations in IL-R1 (p = 0.02) and IL-10 (p = 0.01). Finally, several polymorphisms in the IL-R1 gene (rs13020778, rs2160227, & rs3917267) were associated with the time elapsed until clinical stability (beta = - 0.83, p = 0.03; beta = - 1, p = 0.02 and beta = 1.07, p = 0.008, respectively).

CONCLUSIONS

A genetic variant in NFKBIA was associated with susceptibility to P-CAP in adult Caucasian patients and genetic variants from key cytokines of the innate immune response (Il-4, IL-10, IL-R1 and IL-12B) and NF-κB inhibitors were associated with different phenotypes of severe P-CAP. If validated, these SNPs may help to identify people at risk of P-CAP or severe P-CAP on which preventive measures could be applied.

Significant increase of CTX-M-15-ST131 and emergence of CTX-M-27-ST131 Escherichia coli high-risk clones causing healthcare-associated bacteraemia of urinary origin in Spain (ITUBRAS-2 project)

OBJECTIVES

To assess the microbiological characteristics of Escherichia coli causing healthcare-associated bacteraemia of urinary origin (HCA-BUO) in Spain (ITUBRAS-2 project), with particular focus on ESBL producers and isolates belonging to ST131 high-risk clone (HiRC). Clinical characteristics and outcomes associated with ST131 infection were investigated.

METHODS

A total of 222 E. coli blood isolates were prospectively collected from patients with HCA-BUO from 12 tertiary-care hospitals in Spain (2017-19). Antimicrobial susceptibility and ESBL/carbapenemase production were determined. ST131 subtyping was performed. A subset of 115 isolates were selected for WGS to determine population structure, resistome and virulome. Clinical charts were reviewed.

RESULTS

ESBL-producing E. coli prevalence was 30.6% (68/222). ST131 represented 29.7% (66/222) of E. coli isolates and accounted for the majority of ESBL producers (46/68, 67.6%). The C2/H30-Rx subclone accounted for most ST131 isolates (44/66) and was associated with CTX-M-15 (37/44) and OXA-1 enzymes (27/44). Cluster C1-M27 was identified in 4/10 isolates belonging to subclade C1/H30-R1 and associated with CTX-M-27. Additionally, ST131 isolates showed a high content of other acquired resistance genes, and clade C/ST131 isolates carried characteristic QRDR mutations. They were categorized as uropathogenic E. coli and had higher aggregate virulence scores. ST131 infection was associated with more complex patients, prior use of cephalosporins and inadequate empirical treatment but was not associated with worse clinical outcomes.

CONCLUSIONS

ST131 HiRC is the main driver of ESBL-producing E. coli causing HCA-BUO in Spain, mainly associated with the expansion of subclade CTX-M-15-C2/H30-Rx and the emergence of CTX-M-27-C1/H30-R1 (Cluster C1-M27).

Risk factors associated with inappropriate empirical antimicrobial treatment in bloodstream infections. A cohort study

Introduction: Bloodstream infections (BSI) are a major cause of mortality all over the world. Inappropriate empirical antimicrobial treatment (i-EAT) impact on mortality has been largely reported. However, information on related factors for the election of i-EAT in the treatment of BSI in adults is lacking. The aim of the study was the identification of risk-factors associated with the use of i-EAT in BSI. Methods: A retrospective, observational cohort study, from a prospective database was conducted in a 400-bed acute-care teaching hospital including all BSI episodes in adult patients between January and December 2018. The main outcome variable was EAT appropriation. Multivariate analysis using logistic regression was performed. Results: 599 BSI episodes were included, 146 (24%) received i-EAT. Male gender, nosocomial and healthcare-associated acquisition of infection, a high Charlson Comorbidity Index (CCI) score and the isolation of multidrug resistant (MDR) microorganisms were more frequent in the i-EAT group. Adequation to local guidelines' recommendations on EAT resulted in 91% of appropriate empirical antimicrobial treatment (a-EAT). Patients receiving i-EAT presented higher mortality rates at day 14 and 30 when compared to patients with a-EAT (14% vs. 6%, p = 0.002 and 22% vs. 9%, p < 0.001 respectively). In the multivariate analysis, a CCI score ≥3 (OR 1.90 (95% CI 1.16-3.12) p = 0.01) and the isolation of a multidrug resistant (MDR) microorganism (OR 3.79 (95% CI 2.28-6.30), p < 0.001) were found as independent risk factors for i-EAT. In contrast, female gender (OR 0.59 (95% CI 0.35-0.98), p = 0.04), a correct identification of clinical syndrome prior to antibiotics administration (OR 0.26 (95% CI 0.16-0.44), p < 0.001) and adherence to local guidelines (OR 0.22 (95% CI 0.13-0.38), p < 0.001) were identified as protective factors against i-EAT. Conclusion: One quarter of BSI episodes received i-EAT. Some of the i-EAT related factors were unmodifiable (male gender, CCI score ≥3 and isolation of a MDR microorganism) but others (incorrect identification of clinical syndrome before starting EAT or the use of local guidelines for EAT) could be addressed to optimize the use of antimicrobials.

Short versus long course therapy in the treatment of febrile urinary tract infections in men based on serum PSA values

BACKGROUND

Febrile urinary tract infections (fUTI) in men are frequently complicated with subclinical prostatic involvement, measured by a transient increase in serum prostate-specific-antigen (sPSA). The aim of this study was to evaluate recurrence rates in a 6-month follow-up period of 2-week versus 4-week antibiotic treatment in men with fUTI, based on prostatic involvement. Clinical and microbiological cure rates at the end-of-therapy (EoT) were also assessed.

METHODS

Open label, not-controlled, prospective study. Consecutive men diagnosed of fUTI were included. Duration of therapy was 2 weeks for patients with a sPSA level <5mg/L (short duration therapy, SDT) or 4 weeks for PSA >5 mg/L (long duration therapy, LDT).

RESULTS

Ninety-one patients were included; 19 (20%) received SDT. Median age was 56.9 years (range 23-88). Bacteremia was present in 9.8% of patients (Escherichia coli was isolated in 91%). Both groups had similar demographic, clinical characteristics and laboratory findings. Median PSA levels were 2.3 mg/L in the SDT group vs 23.4 mg/L in the LDT group. In the 6-month visit, 26% of patients had achieved complete follow-up. Nonsignificant differences between groups were found neither in recurrence rates after 6 months (9% in SDT vs 10% in LDT) nor in clinical or microbiological cure rates at EoT (100% in SDT vs 95% in LDT and 95% in SDT vs 93% in LDT respectively).

CONCLUSIONS

One fifth of men with fUTI did not present apparent prostatic involvement. A 2-week regimen seems adequate in terms of clinical, microbiological cure and recurrence rates for those patients without PSA elevation.

Use of Generic Antiretroviral Drugs and Single-Tablet Regimen De-Simplification for the Treatment of HIV Infection in Spain

The present study sought to describe the use of generic drugs and single-tablet regimen (STR) de-simplification for the treatment of human immunodeficiency virus (HIV) infection among 41 hospitals from the cohort of the Spanish HIV/AIDS Research Network (CoRIS). In June 2018, we collected information on when generic antiretroviral drugs (ARVs) were introduced in the different hospitals, how the decisions to use them were made, and how the information was provided to the patients. Most of the nine available generic ARVs in Spain by June 2018 had been introduced in at least 85% of the participating hospitals, except for zidovudine (AZT)/lamivudine (3TC) and AZT. The time difference between the effective marketing date of each generic ARV and its first dispensing date in the hospitals was much shorter for the more recently approved generic ARV since the year 2017. However, only up to 20% of the hospitals de-simplified efavirenz (EFV)/tenofovir disoproxil (TDF)/emtricitabine (FTC), dolutegravir (DTG)/abacavir (ABC)/3TC, and rilpivirine (RPV)/TDF/FTC (to generic EFV+TDF/FTC, DTG+generic ABC/3TC, and RPV+generic TDF/FTC, respectively), whereas the generic STR EFV/TDF/FTC was introduced in 87.8% of the centers. The median times between the date of effective marketing of generic TDF/FTC and the date of de-simplification of EFV/TDF/FTC and RPV/TDF/FTC were 723 [interquartile range (IQR): 369-1,119] and 234 (IQR: 142-264) days, respectively; this time was 155 (IQR: 28-287) days for de-simplification of DTG/ABC/3TC. In conclusion, despite the widespread use of generic ARVs, STRs de-simplification was only undertaken in <20% of the hospitals. There was wide variability in the timing of the introduction of each generic ARV after they were available in the market.

Improvement of pneumococcal pneumonia diagnosis using quantitative real-time PCR targeting lytA in adult patients: a prospective cohort study

OBJECTIVES

The aim of the study was to assess the performance of real-time PCR targeting the lytA gene (rtPCR-lytA) in plasma, urine and nasopharyngeal (NP) samples for the diagnosis of pneumococcal community-acquired pneumonia (P-CAP).

METHODS

Prospective observational study including all consecutive adults with CAP from November 2015 to May 2017. P-CAP was defined if pneumococcus was identified using conventional methods (CM) and/or a positive rtPCR-lytA was detected in blood, urine or NP samples (NP cut-off ≥8000 copies/mL). Diagnostic performance of each test was calculated.

RESULTS

A total of 133 individuals with CAP were included. Of these, P-CAP was diagnosed in 62 (46.6%). The proportion of P-CAP diagnosed by rtPCR-lytA methods was significantly higher than that diagnosed by CM (87.1% versus 59.7%, p 0.005). The rtPCR-lytA identified Streptococcus pneumoniae in 25 patients (40.3% of all individuals with P-CAP) whose diagnosis would have been missed by CM. NP-rtPCR-lytA allowed diagnosis of 62.3% of P-CAP. A nasopharyngeal colonization density ≥2351 copies/mL predicted P-CAP diagnosis (area under the curve = 0.82, sensitivity 83.3%, specificity 80.9%). There was a positive correlation between increasing bacterial load in blood and CURB-65 score (Spearman correlation coefficient r = 0.4, p 0.001), pneumonia severity index (r = 0.3, p 0.02) and time to clinical stability (r = 0.33, p 0.01). Median bacterial load in blood was higher in P-CAP patients with bacteraemia (0.65 × 10³ versus 0 × 10³ copies/mL, p 0.002), intensive care unit admission (0.68 × 10³ versus 0 × 10³ copies/mL, p 0.04) or mechanical ventilation (7.45 × 10³ versus 0 × 10³ copies/mL, p 0.04).

CONCLUSIONS

The use of rtPCR-lytA methods significantly increased the diagnosis of P-CAP compared with CM. Nasopharyngeal swabs rtPCR-lytA detection, with an accurate cut-off value, was the most promising among molecular methods for the diagnosis of P-CAP.

Effectiveness of the combination elvitegravir/cobicistat/tenofovir/emtricitabine (EVG/COB/TFV/FTC) plus darunavir among treatment-experienced patients in clinical practice: a multicentre cohort study

BACKGROUND

The aim of this study was to investigate the effectiveness and tolerability of the combination elvitegravir/cobicistat/tenofovir/emtricitabine plus darunavir (EVG/COB/TFV/FTC + DRV) in treatment-experienced patients from the cohort of the Spanish HIV/AIDS Research Network (CoRIS).

METHODS

Treatment-experienced patients starting treatment with EVG/COB/TFV/FTC + DRV during the years 2014-2018 and with more than 24 weeks of follow-up were included. TFV could be administered either as tenofovir disoproxil fumarate or tenofovir alafenamide. We evaluated virological response, defined as viral load (VL) < 50 copies/ml and < 200 copies/ml at 24 and 48 weeks after starting this regimen, stratified by baseline VL (< 50 or ≥ 50 copies/ml at the start of the regimen).

RESULTS

We included 39 patients (12.8% women). At baseline, 10 (25.6%) patients had VL < 50 copies/ml and 29 (74.4%) had ≥ 50 copies/ml. Among patients with baseline VL < 50 copies/ml, 85.7% and 80.0% had VL < 50 copies/ml at 24 and 48 weeks, respectively, and 100% had VL < 200 copies/ml at 24 and 48 weeks. Among patients with baseline VL ≥ 50 copies/ml, 42.3% and 40.9% had VL < 50 copies/ml and 69.2% and 68.2% had VL < 200 copies/ml at 24 and 48 weeks. During the first 48 weeks, no patients changed their treatment due to toxicity, and 4 patients (all with baseline VL ≥ 50 copies/ml) changed due to virological failure.

CONCLUSIONS

EVG/COB/TFV/FTC + DRV was well tolerated and effective in treatment-experienced patients with undetectable viral load as a simplification strategy, allowing once-daily, two-pill regimen with three antiretroviral drug classes. Effectiveness was low in patients with detectable viral loads.

Delayed Cerebral Vasculopathy in Pneumococcal Meningitis: Epidemiology and Clinical Outcome. A Cohort Study

BACKGROUND

To describe the prevalence, clinical characteristics, impact of systemic steroids exposure and outcomes of delayed cerebral vasculopathy (DCV) in a cohort of adult patients with pneumococcal meningitis (PM).

METHODS

Observational retrospective multicenter study including all episodes of PM from January 2002 to December 2015. DCV was defined as proven/probable/possible based upon clinical criteria and pathological-radiological findings. DCV-patients and non-DCV-patients were compared by univariate analysis.

RESULTS

162 PM episodes were included. Seventeen (10.5%) DCV-patients were identified (15 possible, 2 probable). At admission, DCV-patients had a longer duration of symptoms (>2 days in 58% vs. 25.5% (p 0.04)), more coma (52.9% vs. 21.4% (p 0.03)), lower median CSF WBC-count (243 cells/uL vs. 2673 cells/uL (p 0.001)) and a higher proportion of positive CSF Gram stain (94.1% vs. 71% (p 0.07)). Median length of stay was 49 vs. 15 days (p 0.001), ICU admission was 85.7% vs. 49.5% (p 0.01) and unfavorable outcome was found in 70.6% vs. 23.8% (p 0.001). DCV appeared 1-8 days after having completed adjunctive dexamethasone treatment (median 2,5, IQR=1.5-5).

CONCLUSIONS

One tenth of the PM developed DCV. DCV-patients had a longer duration of illness, were more severely ill, had a higher bacterial load at admission and had a more complicated course. Less than one third of cases recovered without disabilities. The role of corticosteroids in DCV remains to be established.

Impact of a Multifaceted Antimicrobial Stewardship Intervention in a Primary Health Care Area: A Quasi-Experimental Study

The aim of the study was to evaluate the impact of a multifaceted antimicrobial stewardship intervention on antibiotic consumption in a primary health care (PHC) area in Spain. Quasi-experimental study conducted in a PHC area with nine PHC centers, a 400-bed acute care teaching hospital, and 18 nursing homes serving a population of 260,561. The intervention was based on the 2016 CDC Core Elements of Outpatient Antibiotic Stewardship publication and targeted 130 PHC physicians, 41 PHC pediatricians, 19 emergency physicians, and 18 nursing home physicians. The components were commitment, actions for improving antibiotic prescribing, tracking and feedback, and education and experience. The primary outcome was overall antibiotic consumption. Secondary outcomes were consumption of antibiotics to treat pharyngotonsillitis, acute otitis media, acute sinusitis, acute bronchitis, and urinary tract infection (UTI), percentage of patients treated with specific antibiotics, and dispensing costs. Consumption was measured in defined daily doses per 1,000 inhabitants per day (DID) and compared pre- and postintervention (2016 vs. 2018). Overall antibiotic consumption decreased from 16.01 to 13.31 DID (−16.85%). Consumption of amoxicillin/clavulanic acid and quinolones decreased from 6.04 to 4.72 DID (−21.88%) and 1.64 to 1.23 DID (−25.06%), respectively. The percentage of patients treated with antibiotics decreased from 26.99 to 22.41%. The intervention resulted in cost savings of €72,673. Use of antibiotics to treat pharyngotonsillitis, UTI, and acute otitis media, sinusitis, and bronchitis decreased significantly. Our antimicrobial stewardship program led to a decrease in antibiotic consumption and significantly improved the use of antibiotics for the most prevalent PHC infections.

High clonal diversity of ESBL-producing Klebsiella pneumoniae isolates from clinical samples in a non-outbreak situation. A cohort study

Background

Klebsiella pneumoniae has been responsible for a large number of clonal hospital outbreaks. However, some epidemiological changes have been observed since the emergence of CTX-M enzymes in K. pneumoniae.

Aim

To analyse the transmission dynamics of Extended Spectrum β-Lactamase-producing Klebsiella pneumoniae (ESBL-Kp) in an acute care hospital.

Methods

In 2015 a prospective cohort study was conducted. All new consecutive adult patients with ESBL-Kp isolates in all clinical samples were included. Patients with a previous known infection/colonization by ESBL-Kp and patients in high risk areas (e.g., intensive care units) were excluded. Cross-transmission was defined as the carriage of a clonally-related ESBL-Kp between newly diagnosed patients who shared the same ward for ≥48 h with another case, within a maximum time window of 4 weeks. ESBL-production was confirmed using the double-disk diffusion method and PCR. Clonal relationships were investigated by rep-PCR and multilocus sequence typing (MLST).

Results

Sixty ESBL-Kp isolates from 60 patients were included and analysed. Infections and colonizations were classified as hospital-acquired (52%), healthcare-related (40%) or community-acquired (8%).High genetic diversity was detected. When epidemiological clinical data were combined with the rep-PCR, the patterns identified did not show any cases of cross-transmission. ESBL-Kp were detected in 12.5% of environmental samples. No clonal relationship could be established between environmental reservoirs and patients. The genetic mechanism detected in all strains was associated with blaCTX-M genes, and 97% were CTX-M-15.

Conclusions

The dynamics of ESBL-K. pneumoniae isolated in our setting could not be explained by clonal transmission from an index patient. A polyclonal spread of ESBL-Kp was identified.

Polymerase Chain Reaction Versus Blood Culture to Detect Candida Species in High-Risk Patients with Suspected Invasive Candidiasis: The MICAFEM Study

Introduction

We evaluated the diagnostic reliability of serum polymerase chain reaction (PCR) versus blood culture, abdominal fluid or both (composite measure) in patients receiving empirical antifungal treatment for suspected invasive candidiasis.

Methods

This observational, prospective, non-interventional, multicentre study in Spain enrolled 176 critically ill patients admitted to the intensive care unit. Separate blood samples for culture and serum PCR were taken before the start of antifungal therapy. Patient assessment was performed according to each site’s usual clinical practice. The primary end point was concordance between serum PCR and blood culture. Secondary end points were concordance between serum PCR and a positive abdominal fluid sample or the composite measure. Quality indices included sensitivity, specificity, positive/negative predictive values (PPV/NPV) and kappa indices.

Results

Among 175 evaluable patients, rates of Candida detection were similar for serum PCR (n = 16/175, 9.1%) versus blood culture (n = 14/175, 8.0%). Quality indices for serum PCR relative to blood culture were: sensitivity 21.4%; specificity 91.9%; PPV 18.8%; NPV 93.1%; kappa index 0.125. Thirty-two abdominal fluid samples were positive. Quality indices for serum PCR versus abdominal fluid were: sensitivity 31.3%; specificity 83.0%; PPV 15.6%; NPV 92.3%; kappa index 0.100. Quality indices for serum PCR versus the composite measure were: sensitivity 15.8%; specificity 92.7%; PPV 37.5%; NPV 79.9%; kappa index 0.107.

Conclusion

The sensitivity of serum PCR for Candida detection was low and the rate of concordance was low between serum PCR and the other diagnostic techniques used to identify Candida infections. Hospital-based diagnostic tests need optimising to improve outcomes in patients with suspected invasive candidiasis.

Funding

Astellas Pharma Inc.

Electronic supplementary material

The online version of this article (10.1007/s40121-019-0248-z) contains supplementary material, which is available to authorized users.

Relationship Between Biofilm Formation and Antimicrobial Resistance in Gram-Negative Bacteria

Gram-negative microorganisms are a significant cause of infection in both community and nosocomial settings. The increase, emergence, and spread of antimicrobial resistance among bacteria are the most important health problems worldwide. One of the mechanisms of resistance used by bacteria is biofilm formation, which is also a mechanism of virulence. This study analyzed the possible relationship between antimicrobial resistance and biofilm formation among isolates of three Gram-negative bacteria species. Several relationships were found between the ability to form biofilm and antimicrobial resistance, being different for each species. Indeed, gentamicin and ceftazidime resistance was related to biofilm formation in Escherichia coli, piperacillin/tazobactam, and colistin in Klebsiella pneumoniae, and ciprofloxacin in Pseudomonas aeruginosa. However, no relationship was observed between global resistance or multidrug-resistance and biofilm formation. In addition, compared with other reported data, the isolates in the present study showed higher rates of antimicrobial resistance. In conclusion, the acquisition of specific antimicrobial resistance can compromise or enhance biofilm formation in several species of Gram-negative bacteria. However, multidrug-resistant isolates do not show a trend to being greater biofilm producers than non-multiresistant isolates.

Serotype, virulence profile, antimicrobial resistance and macrolide-resistance determinants in Streptococcus agalactiae isolates in pregnant women and neonates in Catalonia, Spain

INTRODUCTION

Streptococcus agalactiae, or group B streptococci (GBS), is the main aetiological agent of early neonatal sepsis in developed countries. This microorganism belongs to the gastrointestinal tract microbiota wherefrom it can colonize the vagina and be vertically transmitted to the child either before or at birth, and subsequently cause infection in the newborn. Approximately, 50% of newborns born to women with GBS become colonized, with 1-2% developing early neonatal infection if no preventive intervention is performed. The aim of this study was to characterize and compare serotypes, virulence factors and antimicrobial resistance of GBS isolates collected from pregnant women and newborns in several hospitals in Catalonia.

METHODS

242 GBS strains were analyzed including 95 colonizers and 68 pathogenic strains isolated from pregnant women, and 79 strains isolated from neonates with sepsis in order to determine serotype, virulence and antimicrobial resistance.

RESULTS

Serotype distribution was different among the three groups, with serotypes Ia and II being significantly more frequent among colonizing strains (p=0.001 and 0.012, respectively). Virulence factors bca and scpB were significantly more frequent among neonatal strains than pathogenic or colonizing strains (p=0.0001 and 0.002, respectively). Pathogenic strains were significantly more resistant to erythromycin, clindamycin and azithromycin than their non-pathogenic counterparts.

CONCLUSIONS

Taking into account that neonatal sepsis represents a significant problem on a global scale, epidemiological surveillance, antimicrobial resistance and GBS virulence at the local level could provide important knowledge about these microorganisms as well as help to improve treatment and prevent invasive infection caused by this microorganism.

Emerging extended-spectrum β-lactamase-producing Klebsiella pneumoniae causing community-onset urinary tract infections: a case-control-control study

The aim of this study was to determine the epidemiology and risk factors associated with community-onset urinary tract infections (CO-UTIs) due to extended-spectrum β-lactamase-producing Klebsiella pneumoniae (ESBL-Kp). A cohort study including all consecutive patients with K. pneumoniae CO-UTI identified from January 2010 to December 2014 was conducted. Patients with CO-UTI due to ESBL-Kp were then included as cases in a retrospective case-control-control study; controls were outpatients with CO-UTI caused by non-ESBL-producing Escherichia coli and K. pneumoniae (non-ESBL-Ec and non-ESBL-Kp, respectively). Each control was matched in a 2:1 ratio according to patient age, sex and year of isolation. Genotyping confirming ESBL was performed by multiplex PCR and sequencing. The prevalence of ESBL-Kp CO-UTIs, calculated among all K. pneumoniae CO-UTIs, increased from 2.4% in 2010 to 10.3% in 2014 (P = 0.01). Among cases, 63.8% were truly community-acquired, and CTX-M-15 was the predominant β-lactamase enzyme type (79.3%). A total of 83 cases and 319 controls were studied. Being a nursing home resident [odds ratio (OR) = 8.8, 95% confidence interval (CI) 2.6-29.4] and previous cephalosporin use (OR = 4.01, 95% CI 1.8-9.2) were risk factors independently associated with CO-UTI due to ESBL-Kp. In conclusion, the prevalence of CO-UTIs due to ESBL-Kp is increasing. In most cases, ESBL-Kp CO-UTIs are community-acquired and produce CTX-M-15 β-lactamase. Exposure to cephalosporins and being a nursing home resident were risk factors associated with ESBL-Kp CO-UTIs. CTX-M-15-producing K. pneumoniae isolates are emerging in the community.

Bacillus species pseudo-outbreak: construction works and collateral damage

We describe the investigation and management of a pseudo-outbreak of Bacillus spp. bacteraemia associated with construction work in an emergency department (ED). During the pseudo-outbreak period 59 out of 3469 (1.7%) blood cultures yielded Bacillus spp. versus 24 out of 7628 (0.31%) in 2012. Material, surfaces, and air samples showed environmental contamination. Cases rapidly declined following the implementation of infection control measures and the end of construction. Construction works at the ED caused environmental contamination that most probably led to the pseudo-outbreak of Bacillus bacteraemia. In hospital settings, the lack of correctly implemented effective barriers during construction may place patients and healthcare providers at risk as well as lead to pseudo-outbreaks.

CTX-M-15-H30Rx-ST131 subclone is one of the main causes of healthcare-associated ESBL-producing Escherichia coli bacteraemia of urinary origin in Spain

OBJECTIVES

The objective of this study was to assess the prevalence and molecular epidemiology of ESBL-producing Escherichia coli causing healthcare-associated (HCA) and community-associated (CA) bacteraemia of urinary origin (BUO) in Spain.

METHODS

An observational cohort study was conducted at eight hospitals from different Spanish geographical areas (2010-11). BUO episodes (n = 425) were classified as HCA (n = 215) and CA (n = 210), and one blood isolate per episode was collected. Susceptibility testing was performed, ESBLs were screened by double-disc diffusion test and ESBL and OXA-1 genes were characterized (PCR and sequencing). Population structure (phylogenetic groups, XbaI-PFGE and MLST) and ST131 subtyping (PCR) were determined. Virulence genes were detected by PCR and virulence score, profiles and extraintestinal pathogenic E. coli (ExPEC) status calculated.

RESULTS

ESBL-producing E. coli prevalence was 9.2% (39/425). ESBL-producing E. coli episodes were significantly associated with HCA-BUO episodes [14% (30/215) versus 4.3% (9/210); P = 0.001]. The highest non-susceptibility proportions corresponded to ciprofloxacin (97.4%), amoxicillin/clavulanate (74.4%), co-trimoxazole (69.2%) and tobramycin (61.5%). Of the 39 ESBL-producing E. coli isolates, 34 produced CTX-M enzymes (21 CTX-M-15, 11 CTX-M-14 and 2 CTX-M-1). Fifteen STs were identified, the B2-ST131 clone being the most prevalent (54%; 21/39). All ST131 isolates were ExPEC and had the highest virulence scores, but they showed less diversity in virulence profiles than other STs. The H30Rx subclone accounted for most ST131 isolates (20/21), co-produced CTX-M-15 (20/20) and OXA-1 (19/20) enzymes and was associated with HCA episodes (16/20).

CONCLUSIONS

The CTX-M-15-ST131-H30Rx subclone is a relevant MDR pathogen causing BUO, mainly HCA episodes. The dominance of this subclone with comparatively less diversity of virulence profiles reflects the spread of a successful and MDR ESBL ST131 lineage in Spain.

Molecular characterisation of acquired and overproduced chromosomal blaAmpC in Escherichia coli clinical isolates

Escherichia coli recovered from three hospitals in Barcelona (Spain) were studied to determine the prevalence of isolates with acquired AmpC (ac-AmpC) and/or overproduced chromosomal AmpC (c-AmpC). Mechanisms involved in blac-AmpC overexpression, blaac-AmpC and the plasmids associated with their distribution as well as the prevalence of plasmid-mediated quinolone resistance (PMQR) in AmpC-producing isolates were also determined. Isolates were selected according to their resistance phenotype. blaac-AmpC, alterations in the blac-AmpC promoter/attenuator, and PMQR genes [qnrA, qnrB, qnrS, aac(6')-Ib-cr and qepA] were characterised by PCR and sequencing. blac-AmpC expression was determined by qRT-PCR. Population structure analysis was performed using PFGE, MLST and phylogenetic group PCR. Plasmids carrying blaac-AmpC were characterised by PCR-based replicon typing and S1-PFGE. IncI1 and IncF plasmids were also analysed by plasmid MLST and replicon sequence typing, respectively. Among 21563 E. coli isolates, 240 (1.1%) overproduced AmpC β-lactamases, including 180 (75.0%) harbouring ac-AmpC (132 CMY-2 variants and 48 DHA-1) and 60 (25.0%) c-AmpC enzymes. Three mutation profiles in the blac-AmpC promoter/attenuator were associated with a 72.5-, 19.9- and 5.8-fold increased expression, respectively. Moreover, 63.3% of ac-AmpC and 43.3% of c-AmpC isolates belonged to B2, D, E or F phylogenetic groups. PMQR was found in 31% of ac-AmpC isolates [38 qnrB4, 8 aac(6')-Ib-cr, 6 qnrS1 and 3 qnrB19] and in 10% of c-AmpC isolates [5 aac(6')-Ib-cr and 1 qnrS1]. IncI1-ST12 and IncF were associated with blaCMY-2 and blaDHA-1, respectively. These results suggest that ac-AmpC β-lactamases were the main mechanism of AmpC production. Isolates and plasmids both showed high genetic diversity.

Epidemiology and risk factors for infections due to AmpC β-lactamase-producing Escherichia coli

OBJECTIVES

To describe the prevalence and risk factors for infection due to AmpC β-lactamase-producing Escherichia coli (AmpC-EC).

METHODS

For the prevalence study, all clinical isolates of E. coli with reduced susceptibility to third-generation cephalosporins were prospectively included from June 2010 to November 2011. For risk factor analysis, a case-control study was conducted. Cases were patients with an infection due to AmpC-EC. Controls were patients infected with cephalosporin-susceptible E. coli, matched 1 : 2. Detection of blaAmpC genes was done with a multiplex AmpC-PCR, and hyperproduction of E. coli chromosomal blaAmpC by quantitative RT-PCR. Alteration of the blaAmpC promoter was studied by PCR and sequencing.

RESULTS

We identified 243 (1.1%) AmpC-EC strains out of 21 563 clinical isolates. Three cases with strains carrying ESBLs, 18 strains that were considered due to colonization and 8 cases lost to clinical follow-up were excluded. Finally, 214 cases were included in the analysis. Ninety-one cases (42.5%) and 269 (62.8%) controls were strictly community acquired (P < 0.001). Thirty-five (16.3%) cases and 186 controls (43.5%) did not have any identifiable risk factor (P < 0.001). Among cases, 158 (73.8%) were found to harbour an acquired AmpC (73.4% CMY-2). Previous use of fluoroquinolones [OR 2.6 (95% CI 1.12-3.36); P = 0.008] was independently associated with AmpC-EC in the multivariate analysis.

CONCLUSIONS

Prevalence of AmpC in E. coli remains low in our area. Plasmid acquisition (CMY type) represents the main mechanism of AmpC production. A high proportion of community-acquired isolates and patients with no identifiable risk factors were found. Previous use of fluoroquinolones was identified as a risk factor.

Bacteraemic pneumococcal pneumonia in COPD patients: better outcomes than expected

The purpose of the study was to compare the clinical characteristics and outcomes of bacteraemic pneumococcal pneumonia (BPP) in chronic obstructive pulmonary disease (COPD) and non-COPD patients. A case-control study was conducted. Cases were any adult with BPP and forced expiratory volume in 1 second (FEV(1)) <80% and FEV(1)/forced expiratory vital capacity (FVC) <70%. Controls were patients with BPP without clinical diagnosis of COPD matched 1:2 by age, gender and date of isolation. Variables included co-morbidities, serotypes, pneumonia severity index (PSI), treatment and mortality. There were 45 cases and 90 controls. No significant differences were found in Charlson scores, antibiotic treatment, serotype distribution and severity. Malignancy, shock and mechanical ventilation were less frequent in COPD patients. One patient died vs 14 controls (p = 0.02). In univariate analysis, shock, multilobar involvement, Charlson score, heart failure and absence of COPD were associated with mortality. After adjustment for the presence of shock there were no differences in mortality. BPP presents less frequently with shock and has a lower mortality rate in COPD patients than in non-COPD patients.

Invasive pneumococcal disease among children in a health district of Barcelona: early impact of pneumococcal conjugate vaccine

This study evaluated the impact of heptavalent pneumococcal conjugate vaccine (HPCV) on invasive pneumococcal disease (IPD) in children aged < or = 5 years in Barcelona, Spain. The incidence of IPD, vaccine uptake and prevalence of nasopharyngeal colonisation were analysed in two different periods: 1999-2001 (pre-licence period), and 2002-2004 (post-licence period). In total, 121 cases of IPD were identified. The overall incidence of IPD decreased from 96.9 cases/100,000 to 90.6 cases/100,000 (OR 0.93, 95% CI 0.69-1.26, p 0.71) between the two periods. The proportion of cases caused by non-vaccine-related serotypes (NVS) increased from 21% to 43.7% (OR 2.9, 95% CI 1.2-7, p 0.01). IPD was diagnosed in seven vaccinated children, six of whom were infected by NVS. There was a trend of diminishing prevalence of resistance to penicillin and macrolides in 2002-2004. The incidence of empyema increased from 1.7 to 8.5/100,000 (OR 4.5, 95% CI 0.91-18, p 0.06). The rate of vaccination ranged from 4.8% to 34%. It was concluded that the rates of IPD in this area did not decrease following the introduction of HPCV. The low uptake of vaccine and the greater proportion of colonisation/infection by NVS probably explain these findings. A trend of increasing empyema was also apparent. A decrease in the prevalence of penicillin and macrolide resistance paralleled the progressive uptake of vaccine.

Similarity between human and chicken Escherichia coli isolates in relation to ciprofloxacin resistance status

BACKGROUND

The food supply is suspected to be a source of fluoroquinolone-resistant Escherichia coli that cause disease in humans, but supporting molecular data are lacking.

METHODS

We performed a molecular-epidemiological comparison, in Barcelona, Spain (1996-1998), of 117 contemporaneous, geographically matched E. coli isolates from humans (35 blood isolates and 33 fecal) or chickens (49 fecal) that were either susceptible (n = 57) or resistant (n = 60) to ciprofloxacin and analyzed them by phylogenetic group, virulence genotype, and O antigens using random amplified polymorphic DNA (RAPD) analysis and pulsed-field gel electrophoresis (PFGE).

RESULTS

When analyzed by phylogenetic distribution, virulence profiles, and O antigens, resistant human isolates were distinct from susceptible human isolates but were largely indistinguishable from chicken isolates, whereas resistant and susceptible chicken isolates were similar. Susceptible human isolates contained more virulence-associated genes and more frequently expressed virulence-associated O antigens than did resistant human or any chicken isolates. Certain resistant human isolates closely resembled chicken isolates by RAPD and PFGE analysis.

CONCLUSIONS

Ciprofloxacin-resistant E. coli may arise de novo in poultry from susceptible progenitors, be transmitted to humans via the food supply, and go on to cause potentially life-threatening infections. If confirmed, these findings would mandate efforts to eliminate this reservoir of drug-resistant pathogens and/or to block their transmission to humans.

Candidemia in neonatal intensive care units: Barcelona, Spain

BACKGROUND

Candida spp. are increasingly important hospital-acquired pathogens in neonatal intensive care units (NICU) and cause considerable mortality in preterm infants. Most studies have been limited to a single institution. The aim of this study was to determine the epidemiology of candidemia in all Barcelona NICUs.

METHODS

We conducted prospective population-based surveillance for candidemia in Barcelona, Spain, during 2002-2003. This report focuses on the results from 5 participating hospitals with NICUs.

RESULTS

We detected 24 cases, resulting in an annual incidence of 32.6 cases per 100,000 live births and 1.1 cases per 100 NICU discharges. Median gestational age was 27.5 weeks (range, 24-40.5), and there were 21 cases among very low birth weight infants. Among the 20 (83%) cases evaluated for the presence of end organ infection, endophthalmitis occurred in 2 cases, and endocarditis, meningitis and peritonitis occurred in 1 case each. Candida parapsilosis was the most frequent species isolated (67%). All isolates were fluconazole-susceptible. Crude mortality was 21%.

CONCLUSIONS

The preponderance of C. parapsilosis candidemias observed in Barcelona NICUs is similar to reports from the literature. Morbidity and mortality associated with neonatal candidemia remain high.

Risk factors for community-onset urinary tract infections due to Escherichia coli harbouring extended-spectrum β-lactamases

OBJECTIVES

Extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli have been increasingly recognized in the community. The aim of this study was to determine the prevalence, types of ESBLs and risk factors for community-onset ESBL-producing E. coli in urinary tract infections (UTIs).

METHODS

Adults with community-onset UTIs due to ESBL-producing E. coli (cases) and non-ESBL-producing E. coli (controls) were identified through records of the clinical microbiology laboratory of the hospital. Two different periods were studied: from January 2000 to January 2001 and from October to December 2003. Controls were matched in a 3:1 ratio to case patients according to age, sex, date of isolation and residence in a long-term care facility. Potential risk factors were recorded. Isoelectric focusing as well as PCR and DNA sequencing were used to characterize the bla(TEM), bla(SHV) and bla(CTX-M) genes. A possible clonal relationship among the strains was determined by repetitive extragenic palindromic sequence PCR.

RESULTS

The prevalence of infection due to ESBL-producing E. coli increased from 0.47% in 2000 to 1.7% in 2003 (P < 0.001). Community-onset ESBL-producing E. coli infection shifted from 50% in the first period to 79.5% in 2003 (P < 0.001). Nineteen cases and 55 matched controls of community-onset ESBL-producing E. coli UTI were included. ESBL-producing E. coli strains were clonally unrelated. On univariate analysis, genitourinary pathology (P < 0.03), previous bacterial infection (P = 0.01), intravenous antibiotic treatment (P = 0.01), hospitalization in the previous 12 months (P = 0.04) and previous exposure to oral second-generation cephalosporins (P < 0.05) were associated with community-onset infection due to ESBL-producing E. coli. In our regression model, only previous exposure to second-generation cephalosporins was strongly associated with E. coli harbouring ESBLs (OR, 21.42; CI 95%, 5.38-85.22; P < 0.05). In the first period, only TEM- and SHV-derived ESBLs were identified. The enzymes were characterized as members of the TEM group (60%), SHV group (16%) and CTX-M group (24%).

CONCLUSIONS

We detected a marked increase in infections due to ESBL-producing E. coli, especially in the community, in the periods studied. Only previous exposure to the oxyimino cephalosporin cefuroxime, and not to ciprofloxacin, aminoglycosides or third-generation cephalosporins, was predictive of an ESBL-producing E. coli community-onset infection in our area. The emergence of the CTX-M type of beta-lactamase in E. coli follows closely the spread of ESBLs in community isolates.

Genotypic and phenotypic resistance patterns at virological failure in a simplification trial with nevirapine, efavirenz or abacavir

BACKGROUND

The NEFA Study was a randomized study comparing nevirapine (NVP), efavirenz (EFV) or abacavir (ABC) as substitutes for protease inhibitors in a large group of HIV-1-infected patients successfully treated with antiretroviral regimens containing protease inhibitors.

OBJECTIVE

To evaluate genotype and phenotype resistance patterns among patients who have experienced virological failure under one of the three study arms.

METHODS

Patients with virological failure, defined as two consecutive determinations of HIV-1 RNA > 200 copies/ml, were analysed for phenotypic susceptibility and HIV-1 mutations.

RESULTS

Of the 460 patients included in the study, 51 (11%) experienced virological failure after 24 months of follow-up while on assigned study medication. A higher proportion of patients in the ABC [25 (17%)] than in the NVP [14 (9%)] or EFV [12 (8%)] arms selected resistance to the study drug (P = 0.04). Moreover, a much higher number of resistance mutations to one or more of the backbone nucleoside reverse transcriptase inhibitor drugs contained in the failing regimen were observed in the ABC than in the EFV or NVP arms. In general, there was a good concordance among genotype and phenotype resistance testing, except for ABC, stavudine and didanosine, where phenotypic resistance testing added valuable information (fold change in the median inhibitory concentration).

CONCLUSIONS

Cross-resistance involving nucleoside reverse transcriptase inhibitor drugs might explain the higher risk of virological failure in patients switched to ABC-containing antiretroviral therapy. Phenotypic resistance testing may be helpful in interpreting unclear genotypic results.

Ciprofloxacin prophylaxis in patients with acute leukemia and granulocytopenia in an area with a high prevalence of ciprofloxacin-resistant Escherichia coli

BACKGROUND

Infection remains the major cause of morbidity and mortality in patients with neutropenia, and the beneficial effects of oral prophylaxis remain controversial.

METHODS

From 1993 to December 1999, the authors analyzed the clinical and microbiologic outcomes of 144 episodes of febrile neutropenia among adult patients with acute leukemia.

RESULTS

Forty-three consecutive episodes occurred among patients who were on ciprofloxacin prophylaxis during 1993-1996 (ciprofloxacin group), and 101 subsequent episodes occurred among patients who were not exposed to ciprofloxacin prophylaxis (control group). There were no differences in clinical presentation, antibiotic treatment received for the episode, or a worse outcome between groups. The rate of bacteremia was similar (12 of 43 patients [28%] vs. 26 of 101 patients [26%], respectively). There was a trend toward a higher rate of Gram positive bacteremia in the control group (12 of 101 patients [12%] vs. 2 of 43 patients [5%]) and a higher rate of Gram negative bacteremia in the ciprofloxacin group (11 of 43 patients [26%] vs. 15 of 101 patients [15%]). Resistance to fluoroquinolones was greater in Escherichia coli blood isolates from patients in the ciprofloxacin group (7 of 8 patients vs. 2 of 9 patients; P = 0.02).

CONCLUSIONS

The current results suggest that fluoroquinolone prophylaxis for patients with febrile neutropenia may be abandoned safely in areas with a high prevalence of ciprofloxacin-resistant enterobacteria.

Hospital-acquired pneumococcal bacteremia

To assess the most relevant features of hospital-acquired pneumococcal bacteremia, all cases of pneumococcal bacteremia at a single teaching hospital that occurred during 1988-2000 were prospectively studied. During this period, 374 cases of pneumococcal bacteremia were documented; 39 (10%) of these episodes were hospital acquired. Twenty-nine (74%) cases occurred during the period of December through May. Eleven (28%) of 39 patients had received antimicrobial agents in the month before the onset of bacteremia. All patients had underlying diseases that predisposed them to pneumococcal infection. The most common origin of infection was the respiratory tract, followed by the intra-abdominal region. Fifteen strains were fully susceptible to penicillin, and 20 were intermediately resistant. Only 25 strains were susceptible to erythromycin; all strains that were resistant to erythromycin were penicillin nonsusceptible. Eighteen (46%) of 39 patients died; the mortality rate related to infection was 39%.

Failure of macrolide antibiotic treatment in patients with bacteremia due to erythromycin-resistant Streptococcus pneumoniae

The rate of macrolide resistance among Streptococcus pneumoniae is increasing, but some investigators have questioned its clinical relevance. We conducted a matched case-control study of patients with bacteremic pneumococcal infection at 4 hospitals to determine whether development of breakthrough bacteremia during macrolide treatment was related to macrolide susceptibility of the pneumococcal isolate. Case patients (n=86) were patients who had pneumococcal bacteremia and an isolate that was either resistant or intermediately resistant to erythromycin. Controls (n=141) were patients matched for age, sex, location, and year that bacteremia developed who had an erythromycin-susceptible pneumococcus isolated. Excluding patients with meningitis, 18 (24%) of 76 case patients and none of 136 matched controls were taking a macrolide when blood was obtained for culture (P=.00000012). Moreover, 5 (24%) of 21 case patients with the low-level-resistant M phenotype and none of 40 controls were taking a macrolide (P=.00157). These data show that development of breakthrough bacteremia during macrolide or azalide therapy is more likely to occur among patients infected with an erythromycin-resistant pneumococcus, and they also indicate that in vitro macrolide resistance resulting from both the efflux and methylase mechanisms is clinically relevant.

Emergence and dissemination of quinolone-resistant Escherichia coli in the community

We studied the evolution of resistance to quinolones in Escherichia coli from 1992 to 1997 in Barcelona, Spain. An increasing proportion of quinolone-resistant E. coli (QREC) infections was observed. QREC strains were more common in patients with nosocomial infections but also increased in patients with community-acquired infections (9% in 1992 to 17% in 1996). Seventy (12%) of 572 episodes of E. coli bacteremia were due to QREC. Factors significantly associated with QREC bacteremia were the presence of underlying disease, recent exposure to antibiotics, and bacteremia of unknown origin. In the multivariate analysis, only prior exposure to antimicrobial agents (P < 0.001; odds ratio [OR] = 2), specifically, to quinolones (P < 0. 001; OR = 14), and the presence of a urinary catheter (P < 0.001; OR = 2) were significantly associated with QREC bacteremia. Among 16 QREC isolates from cultures of blood of community origin selected at random, 13 different pulsed-field gel electrophoresis patterns were recognized, showing the genetic diversity of these isolates and in turn indicating the independent emergence of QREC in the community. The prevalence of QREC in the feces of healthy people was unexpectedly high (24% in adults and 26% in children). A survey of the prevalence of QREC of avian and porcine origin revealed a very high proportion of QREC in animal feces (up to 90% of chickens harbored QREC). The high prevalence of QREC in the stools of healthy humans in our area could be linked to the high prevalence of resistant isolates in poultry and pork.

Thoracic infection caused by Streptococcus milleri

The objective of this study was to increase our understanding of the importance of members of the Streptococcus milleri (SM) group as respiratory pathogens, by studying the epidemiological and clinical features of thoracic infections caused by this group and comparing the epidemiology and prognosis of empyema caused by SM with cases of pneumococcal aetiology. The clinical histories and microbiology reports were reviewed in 27 cases of thoracic infection caused by SM over a period of 8 yrs. Cases of pneumococcal empyema that occurred during the same period were also analysed. Diagnoses were made of cases of empyema, including six with pneumonia and one with pulmonary abscess, three cases of pneumonia and two of mediastinitis. In 17 cases, SM was the only pathogen isolated. There was a history of instrument or surgical procedures on the digestive or respiratory tract in 59%. Secondary bacteraemia was documented in three cases. The treatment administered, a combination of antibiotics and surgery, was successful in 22 of 27 (81%) of cases. All strains were susceptible to penicillin. When the characteristics of the empyemas caused by monomicrobial SM infection were compared with those of pneumococcal aetiology from the same period of study, significant differences were found with respect to age, origin of the infection and the need for surgery. In conclusion, thoracic infections caused by Streptococcus milleri are largely pleural. They are polymicrobial in one-third of cases, commonly acquired in hospital and, in most patients, associated with major surgery and/or surgical procedures of the respiratory or digestive tract. The empyema frequently requires thoracotomy for complete resolution.

Urovirulence determinants in Escherichia coli strains causing prostatitis

To define the urovirulence properties of Escherichia coli strains producing prostatitis, E. coli strains isolated from men with acute (7 strains) or chronic (23) prostatitis were compared with E. coli isolates from women with pyelonephritis (30), acute cystitis (60), or complicated urinary tract infection (UTI; 30). Strains from prostatitis patients were significantly more likely to express hemolysin than were strains causing complicated UTI (73% vs. 43%; P = .02) and more often demonstrated hybridization with the cytotoxic necrotizing factor-1 (CNF-1) probe (63%) than did strains from women (44%-48%). P fimbrial expression was highest among pyelonephritis (73%) and prostatitis strains (53%) and lowest among E. coli from women with complicated UTI (23%) and cystitis (30%; P < .05, prostatitis strains vs. either of the latter 2 groups). Results suggest that E. coli strains producing prostatitis generally possess urovirulence profiles similar to those of strains from women with acute uncomplicated pyelonephritis and that hemolysin and CNF-1 are especially prevalent in prostatitis strains.

Epidemiology of an unusually prolonged outbreak of typhoid fever in Terrassa, Spain

An unusually prolonged outbreak of typhoid fever, from 1988 to 1994, in Terrassa (Barcelona, Spain), was caused by a casual food handler who was a carrier. The pattern of this outbreak suggested intermittent low-level exposure to Salmonella typhi. We found 70 patients with S. typhi infections, 52 of whom were available for study. Medical records were reviewed and patients were interviewed with use of a standard questionnaire. Phage typing and pulsed-field gel electrophoresis (PFGE) for strain subtyping were used to confirm the epidemiological data. The 27 outbreak strains shared the same phage type and the same PFGE pattern. Four sporadic strains shared the same phage type as the outbreak strain. PFGE was found to be useful for differentiating strains for epidemiological purposes.

Seven-year review of bacteremia caused by Streptococcus milleri and other viridans streptococci

The Streptococcus milleri group is associated with a spectrum of serious suppurative infections that have not been well defined. The purposes of this study were to ascertain the clinical significance of Streptococcus milleri bacteremia and to determine the epidemiological, clinical, and microbiological features of these infections compared to those caused by other viridans streptococci. All cases of streptococcal bacteremia observed in a Spanish hospital in the period from January 1988 to December 1994 were reviewed. Of 137 cases of Streptococcus milleri infection, 33 (24%) were documented cases of bacteremia. Twenty-four patients were men (mean age 57.8 +/- 17.4 years). The majority of infections were abdominal in origin (20/33), the most frequent diagnoses being cholangitis/cholecystitis (18%) and appendicitis (12%). The origin of infection could not be established in three cases. Nine cases of bacteremia (27%) were polymicrobial. Six patients (18%) had septic shock; in four the infection was polymicrobial, and in two the infection was of abdominal origin. Eighteen of the 33 patients (54%) required surgery. Five patients died. All 33 Streptococcus milleri isolates were susceptible to penicillin. Twenty-two cases of bacteremia caused by other viridans streptococci were observed during the same period. There were no statistically significant differences between the two groups in terms of age, sex, mortality, rate of polymicrobial infection, rate of nosocomial acquisition of bacteremia, or the occurrence of shock. An abdominal origin of infection was more frequent in Streptococcus milleri bacteremia (p = 0.0001); a cardiovascular origin was more frequent in the viridans group (p = 0.01), as was a diagnosis of endocarditis (p = 0.004). Four patients with viridans streptococci bacteremia required surgery versus 18 patients with Streptococcus milleri bacteremia (p = 0.01). Viridans streptococci were notably less susceptible to penicillin (89%), clindamycin (79%), and erythromycin (79%).

[Fluoroquinolone and aminoglycoside resistance in chromosomal cephalosporinase-overproducing gram-negative bacilli strains with inducible beta-lactamase]

INTRODUCTION

The increasing prevalence of stable derepressed mutants over-producers of type I chromosomal cephalosporinase in inducible Enterobacteriaceae and Pseudomonas aeruginosa challenges the adequacy of third generation cephalosporins in the empirical treatment of certain nosocomial infections. We sought to determine the frequency of stable over-producers of type I enzyme and their associated resistance to fluoroquinolones and aminoglycosides.

METHODS

Disc-diffusion and MIC determinations to extended-spectrum beta-lactams, imipenem, ciprofloxacin and gentamicin were performed in all cell isolates of inducible enteric bacteria (Enterobacter spp., Citrobacter spp., Serratia spp., Morganella morganii, Providencia spp.) and P. aeruginosa collected during the period of study (1992-1993).

RESULTS

A total of 1,426 isolates of inducible enteric bacteria and P. aeruginosa were studied. Each one represented a single patient. Among the 511 isolates of enteric bacteria 15.1% of strains were found to be stable derepressed mutants (Serratia 2.2%; Morganella spp., 3%; Providencia and Proteus 3%; Citrobacter spp., 10%; Enterobacter spp., 23.6%); among the 916 P. aeruginosa isolates studied, 9.2% were stable over-producers. Among Citrobacter, Providencia and Proteus spp., 53.1% of stable over-producers were resistant to ciprofloxacin versus 20.2% of non-over-producers (p < 0.01); in P. aeruginosa, 35.3% of over-producers were resistant to gentamicin versus 25.0% in non-over-producers (p < 0.01).

CONCLUSION

The prevalence of stable derepressed mutants is high among enteric bacteria and P. aeruginosa with type I inducible beta-lactamase. These strains frequently exhibit resistance to fluoroquinolones and aminoglycosides, reducing considerably the available therapeutic options.

[Pleural empyema caused by Legionella pneumophila]

Although pleural effusion is not uncommon in legionellosis, the development of empyema and the demonstration of the organism in pleural fluid are exceptional. We report four patients with pleural empyema with isolation of Legionella pneumophila in the pleural fluid culture. The patients were three males and one female, with ages ranging from 36 and 83 years. All had left pleuritic pain, fever and pleural effusion. The appearance of pleural effusion was purulent in two cases and serofibrinous in the other two. Initially, the diagnosis was only suspected in one patient. The other three received inadequate treatment, until the result of the culture of the pleural fluid in BCYE-alpha medium was known. After giving erythromycin therapy at high doses, the outcome was favorable in the four patients. It is concluded that, in the absence of another diagnosis, the presence of L. pneumophila should be systematically investigated in the pleural fluid although the disease is not clinically suspected.

[Type 1 fimbriae, P fimbriae and X adhesins in Escherichia strains causing pyelonephritis, cystitis and recurrent urinary infections]

The presence of type 1 fimbriae, P fimbriae and X adhesins in 30 strains of Escherichia coli producing pyelonephritis, 30 strains producing cystitis, and 30 strains producing recurrent urinary infections are compared. All the strains were collected from adult women without risk factors for infections of the urinary tract. The presence of P fimbriae was 73% in strains producing pyelonephritis, 40% in strains producing cystitis and 20% in strains producing recurrent urinary infections; the presence of X adhesins was 3%, 0, and 17% respectively. There were, in consequence, significant differences between the groups studied; however, such differences were not observed with respect to the presence of type 1 fimbriae, which was 97%, 97% and 90%, respectively. We conclude that P fimbriae act as a factor of greater virulence in the strains of E. coli producing pyelonephritis and X adhesins are found almost exclusively in the strains producing recurrent urinary infections.