Genome sequence of a virulent and hypermucoviscous-like Klebsiella michiganensis clinical isolate

OBJECTIVES

The hypermucoviscous-like phenotype has been described in Klebsiella pneumoniae species complex (KpSC) and was described as a contributor of increased virulence. This study described the characterization and whole-genome sequencing of an antibiotic susceptible and hypermucoviscous-like Klebsiella michiganensis 9273 clinical isolate.

DATA DESCRIPTION

Here, we report the genome sequence of a K. michiganensis clinical isolate obtained from a urinary tract infection exhibiting the hypermucoviscous-like phenotype. The draft genome sequence consisted of 145 contigs and ~ 6.6 Mb genome size. The annotation revealed 6648 coding DNA sequences and 56 tRNA genes. The strain belongs to the sequence type (ST) 50, and the OXY-1 beta-lactam resistance gene, aph(3')-Ia gene for aminoglycoside resistance and multidrug efflux pumps were identified. The fyuA siderophore receptor of yersiniabactin siderophore was identified. Increased virulence was observed in Galleria mellonella larvae model and increased capsule production was determined by uronic acid quantification. The clinical implications of this phenotype are unknown, but the patient outcome might worsen compared to susceptible- or MDR-classical K. michiganensis isolates.

Bacterial incidence and drug resistance from pathogens recovered from blood, cerebrospinal and pleural fluids in 2019-2020. Results of the Invifar network

Background

Antimicrobial resistance is a global concern. Analysis of sterile fluids is essential because microorganisms are defined as significant in most cases. Blood, cerebrospinal, and pleural fluids are frequently received in the microbiology lab because they are associated with considerable rates of morbi-mortality. Knowledge of epidemiology in these samples is needed to choose proper empirical treatments due to the importance of reducing selection pressure.

Methods

We used retrospective laboratory data of blood, CSF, and pleural fluid collected from patients in Mexico between 2019 and 2020. Each laboratory identified the strains and tested susceptibility using its routine methods. For Streptococcus pneumoniae, a comparative analysis was performed with data from the broth microdilution method.

Results

Forty-five centers participated in the study, with 30,746 clinical isolates from blood, 2,429 from pleural fluid, and 2,275 from CSF. For blood and CSF, Staphylococcus epidermidis was the most frequent. For blood, among gram negatives, the most frequent was Escherichia coli. Among Enterobacterales, 9.8% of K. pneumoniae were carbapenem-resistant. For S. pneumoniae, similar resistance percentages were observed for levofloxacin, cefotaxime, and vancomycin. For CSF, the most frequent gram-negative was E. coli. In Acinetobacter baumannii, carbapenem resistance was 71.4%. The most frequent species detected for pleural fluid was E. coli; in A. baumannii, carbapenem resistance was 96.3%.

Conclusion

Gram-negative bacteria, with E. coli most prevalent, are frequently recovered from CSF, blood, and pleural fluid. In S. pneumoniae, the routine, conventional methods showed good agreement in detecting resistance percentages for erythromycin, levofloxacin, and vancomycin.

Diagnosis of bacterial meningitis caused by Streptococcus pneumoniae, Neisseria meningitidis, and Haemophilus influenzae using a multiplex real-time PCR technique

Bacterial meningitis is one of the diseases that, despite the introduction of several vaccines, remains a serious public health concern. Streptococcus pneumoniae (Spn), Neisseria meningitidis (Nm), and Haemophilus influenzae (Hi) are responsible for most cases diagnosed in children, adolescents, and adult population. Rapid, sensitive, and specific laboratory assays are critical for effective diagnosis and treatment, particularly in countries like Mexico in which culture positivity rates are very low due to the use of antibiotics prior to sample collection and to delay in transporting samples to the laboratory. The aim of this study was to evaluate the use of real-time polymerase chain reaction (RT-PCR) of cerebrospinal fluid (CSF) as a rapid diagnostic test for bacterial meningitis and compare these results with bacterial culture in three general hospitals in Mexico. During a 5-year period (2014-2018), a total of 512 CSF samples obtained from patients in whom infectious meningitis was suspected as initial clinical diagnosis were tested with RT-PCR with species-specific targets for the three pathogens. For Spn, 5.07% samples were RT-PCR positive; 0.39% for Nm and none for Hi. Only five RT-PCR Spn positive samples had a positive culture. Sensitivity and specificity estimates for RT-PCR are 100% and 95.46%, respectively. DNA amplification methods can provide better sensitive diagnostic tests than the reference standard, which is culture, particularly when antimicrobial treatment is initiated before clinical samples can be obtained.

Analysis of biofilm production and expression of adhesion structures of circulating Clostridioides difficile strains from Mexico

INTRODUCTION

Clostridioides difficile biofilms are believed to protect the pathogen from antibiotics, in addition to potentially contributing to recurrent infections.

METHODOLOGY

Biofilm production of 102 C. difficile isolates was determined using the crystal violet staining technique, and detachment assays were performed. The expression levels of cwp84 and slpA genes were evaluated by real-time PCR on selected isolates.

RESULTS

More than 70% of isolates (75/102) were strong biofilm producers, and the highest detachment of biofilm was achieved with the proteinase K treatment (>90%). The overall mean expression of cwp84 was higher in RT027 than in RT001 (p=0.003); among strong biofilm-producing strains, the slpA expression was lower in RT027 than in RT001 (p<0.000).

CONCLUSIONS

Proteins seem to have an important role in the biofilm's initial adherence and maturation. slpA and cwp84 are differentially expressed by C. difficile ribotype and biofilm production level.

Efficacy and In Vitro Activity of Novel Antibiotics for Infections With Carbapenem-Resistant Gram-Negative Pathogens

Infections by Gram-negative multi-drug resistant (MDR) bacterial species are difficult to treat using available antibiotics. Overuse of carbapenems has contributed to widespread resistance to these antibiotics; as a result, carbapenem-resistant Enterobacterales (CRE), A. baumannii (CRAB), and P. aeruginosa (CRPA) have become common causes of healthcare-associated infections. Carbapenems, tigecycline, and colistin are the last resource antibiotics currently used; however, multiple reports of resistance to these antimicrobial agents have been documented worldwide. Recently, new antibiotics have been evaluated against Gram-negatives, including plazomicin (a new aminoglycoside) to treat CRE infection, eravacycline (a novel tetracycline) with in vitro activity against CRAB, and cefiderocol (a synthetic conjugate) for the treatment of nosocomial pneumonia by carbapenem-non-susceptible Gram-negative isolates. Furthermore, combinations of known β-lactams with recently developed β-lactam inhibitors, such as ceftazidime-avibactam, ceftolozane-tazobactam, ceftazidime-tazobactam, and meropenem-vaborbactam, has been suggested for the treatment of infections by extended-spectrum β-lactamases, carbapenemases, and AmpC producer bacteria. Nonetheless, they are not active against all carbapenemases, and there are reports of resistance to these combinations in clinical isolates.This review summarizes and discusses the in vitro and clinical evidence of the recently approved antibiotics, β-lactam inhibitors, and those in advanced phases of development for treating MDR infections caused by Gram-negative multi-drug resistant (MDR) bacterial species.

An Update on Clostridioides difficile Binary Toxin

Infection with Clostridioides difficile (CDI), a common healthcare-associated infection, includes symptoms ranging from mild diarrhea to severe cases of pseudomembranous colitis. Toxin A (TcdA) and toxin B (TcdB) cause cytotoxicity and cellular detachment from intestinal epithelium and are responsible for CDI symptomatology. Approximately 20% of C. difficile strains produce a binary toxin (CDT) encoded by the tcdA and tcdB genes, which is thought to enhance TcdA and TcdB toxicity; however, the role of CDT in CDI remains controversial. Here, we focused on describing the main features of CDT and its impact on the host, clinical relevance, epidemiology, and potential therapeutic approaches.

649. Evaluation of the NG-Test CARBA 5® in Enterobacteriaceae and P. aeruginosa from Clinical Isolates

Background

Identification of carbapenemase-producing organisms like Enterobacteriaceae and P. aeruginosa is important for treatment decisions and infection control. Identification methods require time and technical training. Lateral flow immunoassay NG-Test CARBA 5® exempt these needs. In Mexico there is no evaluation of it on clinical isolates. It is important to define their diagnostic accuracy.

Methods

We collected 103 clinical strains of Enterobacteriaceae and P. aeruginosa resistant to carbapenems, from 2019 to 2020 from: National Institute of Rehabilitation (INR), National Institute of Cancerology, General Hospital Dr. Manuel Gea González and Hospital Civil de Guadalajara Fray Antonio Mayor. Analyzed in INR’s microbiology laboratory, resistance was corroborated with broth Microdilution Method (CLSI 2020). The carbapenemases was demonstrated by phenotypic methods (CLSI 2021). A homemade PCR was done and sequencing for encoding genes: NDM, KPC, GES, VIM, IMP and OXA-48-like. We analyzed concordance of the NG-Test CARBA 5® versus PCR with kappa coefficient.

Results

Seven discarded, 96 strains entered the analysis: Enterobacteriaceae (73%), P. aeruginosa (27%) (Table1). The carbapenemase-producing organisms were: 1) 56 Enterobacteriaceae, 30% Class B; 2) 23 P. aeruginosa, 90% Class B. NG-Test CARBA 5® for Enterobacteriaceae demonstrated greater sensitivity, specificity, and NPV (table 2). Kappa coefficient of concordance was 0.92 for Enterobacteriaceae and 0.59 for P. aeruginosa (table 2), and discrepancies in table 3. Sequencing of carbapenemase-producing organisim can be find in table 4.

Title 1. Clinical isolates by hospital

Conclusion

The most frequent enzyme were Ambler Class B, consistent with national reports. Sensitivity and specificity was like reported in other series. In P. aeruginosa, errors have already been reported in IMP-type enzymes, ours mainly with IMP-75. To our knowledge there are no reports of the following enzyme variants identified by NG-Test CARBA 5®: KPC-82, VIM-67, IMP-62, and IMP-75. NG-Test CARBA 5® showed high concordance with PCR for Enterobacteriaceae, it has the advantage of being a quick and easy-to-use detection tool. In P. aeruginosa despite the results without solid evidence, we recommend complementing the test with other phenotypic identification tests.

Table 2. Kappa Concordance Coefficient of NG-Test CARBA 5® and PCR

Disclosures

All Authors: No reported disclosures

International Nosocomial Infection Control Consortium (INICC) report, data summary of 45 countries for 2013-2018, Adult and Pediatric Units, Device-associated Module

BACKGROUND

We report the results of INICC surveillance study from 2013 to 2018, in 664 intensive care units (ICUs) in 133 cities, of 45 countries, from Latin-America, Europe, Africa, Eastern-Mediterranean, Southeast-Asia, and Western-Pacific.

METHODS

Prospective data from patients hospitalized in ICUs were collected through INICC Surveillance Online System. CDC-NHSN definitions for device-associated healthcare-associated infection (DA-HAI) were applied.

RESULTS

We collected data from 428,847 patients, for an aggregate of 2,815,402 bed-days, 1,468,216 central line (CL)-days, 1,053,330 mechanical ventilator (MV)-days, 1,740,776 urinary catheter (UC)-days. We found 7,785 CL-associated bloodstream infections (CLAB), 12,085 ventilator-associated events (VAE), and 5,509 UC-associated urinary tract infections (CAUTI). Pooled DA-HAI rates were 5.91% and 9.01 DA-HAIs/1,000 bed-days. Pooled CLAB rate was 5.30/1,000 CL-days; VAE rate was 11.47/1,000 MV-days, and CAUTI rate was 3.16/1,000 UC-days. P aeruginosa was non-susceptible (NS) to imipenem in 52.72% of cases; to colistin in 10.38%; to ceftazidime in 50%; to ciprofloxacin in 40.28%; and to amikacin in 34.05%. Klebsiella spp was NS to imipenem in 49.16%; to ceftazidime in 78.01%; to ciprofloxacin in 66.26%; and to amikacin in 42.45%. coagulase-negative Staphylococci and S aureus were NS to oxacillin in 91.44% and 56.03%, respectively. Enterococcus spp was NS to vancomycin in 42.31% of the cases.

CONCLUSIONS

DA-HAI rates and bacterial resistance are high and continuous efforts are needed to reduce them.

Diversity of Circulating Clostridioides difficile Ribotypes in Mexico and Susceptibility to Fidaxomicin, Vancomycin, and Metronidazole

In this study, we report the results of the epidemiological analysis of Clostridioides difficile ribotypes (RTs) and antimicrobial susceptibility testing. Most isolates were RT027, representing 73% (84/115) of isolates. No isolates with reduced susceptibility to fidaxomicin were found; however, 38 (33.04%) isolates had reduced susceptibility to metronidazole, and 7 isolates (6.1%) had reduced susceptibility to vancomycin. These findings highlight the need for continuous surveillance of C. difficile RTs and antimicrobial susceptibility testing.

Dissemination of bla NDM- 1 Gene Among Several Klebsiella pneumoniae Sequence Types in Mexico Associated With Horizontal Transfer Mediated by IncF-Like Plasmids

Nosocomial infections caused by multidrug-resistant (MDR) Klebsiella pneumoniae are a major health problem worldwide. The aim of this study was to describe NDM-1-producing K. pneumoniae strains causing bacteremia in a tertiary referral hospital in Mexico. MDR K. pneumoniae isolates were screened by polymerase chain reaction for the presence of resistance genes. In resistant isolates, plasmids were identified and conjugation assays were performed. Clonal diversity and the sequence types were determined by pulsed-field gel electrophoresis and multilocus sequence typing. A total of 80 K. pneumoniae isolates were collected from patients with bacteremia over a 1-year period. These isolates showed a level of resistance of 59% (47/80) to aztreonam, 56-60% (45-48/80) to cephalosporins, 54% (43/80) to colistin and 12.5% (10/80) to carbapenems. The carbapenem resistant isolates were bla NDM- 1 carriers and negative for bla KPC, bla NDM, bla IMP, bla VIM and bla OXA- 48 -like carbapenemases genes. Conjugative plasmids IncFIIA and IncF group with sizes of 82-195 kbp were carriers of bla NDM- 1, bla CTX-M- 15, bla TEM- 1, aac(6')-Ib and/or aac(3')-IIa. Clonal variability and nine different multilocus sequence types were detected (ST661, ST683, ST1395, ST2706, ST252, ST1198, ST690, ST1535, and ST3368) for the first time in the isolates carrying bla NDM- 1 in Mexico. This study demonstrates that bla NDM- 1 has remained within this hospital in recent years and suggests that it is currently the most prevalent carbapenemase among K. pneumoniae MDR strains causing bacteremia in Mexico. The horizontal transfer of bla NDM- 1 gene through IncF-like plasmids among different clones demonstrates the dissemination pathway of antimicrobial resistance and underscore the need for strong and urgent joint measures to control the spread of NDM-1 carbapenemase in the hospital.

Analysis of biofilm production and expression of adhesion structures of circulating Clostridioides difficile strains from Mexico

INTRODUCTION

Clostridioides difficile biofilms are believed to protect the pathogen from antibiotics, in addition to potentially contributing to recurrent infections.

METHODOLOGY

Biofilm production of 102 C. difficile isolates was determined using the crystal violet staining technique, and detachment assays were performed. The expression levels of cwp84 and slpA genes were evaluated by real-time PCR on selected isolates.

RESULTS

More than 70% of isolates (75/102) were strong biofilm producers, and the highest detachment of biofilm was achieved with the proteinase K treatment (>90%). The overall mean expression of cwp84 was higher in RT027 than in RT001 (p=0.003); among strong biofilm-producing strains, the slpA expression was lower in RT027 than in RT001 (p<0.000).

CONCLUSIONS

Proteins seem to have an important role in the biofilm's initial adherence and maturation. slpA and cwp84 are differentially expressed by C. difficile ribotype and biofilm production level.

Microbial diversity and colonization patterns of two step-down care units from a tertiary care hospital

Nosocomial surfaces are potential pathogen reservoirs. Our aim was to describe the microbial diversity and analyze microbial patterns of healthcare-associated pathogens in two step-down-care-units at a tertiary care hospital. We monitored infected patients over 45 days to describe microbial diversity and colonization patterns. A total of 2762 isolates were recovered from the sampled sites, coagulase-negative staphylococci represented 44.64% (1233/2762) of the isolates. The most frequently recovered ESKAPE species (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter cloacae) were A. baumannii (7.53%; 208/2762 isolates) and E. faecium/Enterococcus faecalis (5.18%; 143/2762). We recovered a high diversity of species, including potential pathogens. A. baumannii was detected more frequently on diverse surfaces and persisted in patients’ nostrils during the hospital stay.

Dynamics of colonization in patients with health care-associated infections at step-down care units from a tertiary care hospital in Mexico

BACKGROUND

Patient colonization has been suggested as a risk factor in hospital-associated infections (HAI) development, which are of the most frequent complications in hospitals.

OBJECTIVE

To examine the colonization process and possible transmission routes of HAI-causative agents in step-down care unit (SDCU) patients.

METHODS

Patients admitted to SDCU within 48 hours of admission that had no evidence of infection present, nurse health care workers (HCWs), and relatives of infected patients were included. Participants were sampled and cultured at different times in different body surfaces. Environmental surfaces and medical devices were also sampled. Antimicrobial susceptibility and clonal relatedness were determined in selected HAI-causative agents, environmental, nurse HCWs, and patient isolates.

RESULTS

A total of 2,735 isolates corresponding to 126 species were identified. Of the 11 patients included, 8 developed 1-3 HAIs (14 isolates recovered as HAI-causative agents). Acinetobacter baumannii (36% of infections) was distributed in clone A (n = 1), B (n = 3), and F (n = 1); Klebsiella pneumoniae (29%) in clones A (n = 2) and B (n = 1) and Enterobacter cloacae (7%) in one clone A. Causative agents were progressively recovered from environmental surfaces and medical devices before and after HAI onset.

CONCLUSIONS

Highly related strains were recovered from environmental surfaces, patients, and nurse HCWs before and after HAI outcome. This is a first step to examine colonization process in SDCU settings and provides a base for further studies to understand colonization dynamics and the role of patients' relatives and nurse HCWs in organism transmission in the SDCU.

Clostridioides difficile infections among healthcare workers

Health care workers (HCWs) are constantly exposed to patients with Clostridiodes difficile infection (CDI) although their risk developing infection is unknown. We designed a retrospective comparative study including HCWs with CDI and 2 comparator groups with a 1:2 ratio: HCWs without CDI and admitted patients with CDI. Antibiotics were the strongest risk factor for developing CDI in HCWs whether or not there was clinical exposure to patients with this infection.

Safety, immunogenicity, and efficacy of a Clostridioides difficile toxoid vaccine candidate: a phase 3 multicentre, observer-blind, randomised, controlled trial

BACKGROUND

In the absence of a licensed vaccine, Clostridioides (formerly Clostridium) difficile infection represents a substantial health burden. The aim of this study was to evaluate the efficacy, immunogenicity, and safety of a toxoid vaccine candidate.

METHODS

We did a phase 3 multicentre, observer-blind, randomised, controlled trial at 326 hospitals, clinics, and clinical research centres in 27 countries in the USA, Canada, Latin America, Europe, and the Asia-Pacific region. We included adults aged 50 years or older who were considered to be at an increased risk of C difficile infection because they had previously had two hospital stays (each ≥24 h in duration) and had received systemic antibiotics in the previous 12 months (risk stratum 1), or because they were anticipating being admitted to hospital for 72 h or more for elective surgery within 60 days of enrolment (risk stratum 2). Eligible participants were stratified by geographical region and the two risk strata, and randomly assigned (2:1), with a fixed block size of three, to receive either a C difficile toxoid vaccine candidate, containing toxoids A and B (C difficile vaccine candidate group), or a placebo vaccine (placebo group). Participants, investigators, and personnel responsible for collecting safety data and analysing blood and stool samples were masked to group assignment. Personnel responsible for study product preparation and administration were not masked to group assignment. One dose (0·5 mL) of C difficile vaccine candidate or placebo vaccine was administered intramuscularly on days 0, 7, and 30. The primary outcome was the efficacy of the vaccine in preventing symptomatic C difficile infection, defined as having three or more loose stools in a period of 24 h or less, loose stools for 24 h or more, and a PCR-positive test for C difficile toxin B in a loose stool sample, within 3 years after the final vaccine dose. The primary outcome was measured in the modified intention-to-treat population (ie, all participants who received at least one injection of the assigned vaccine). The safety of the vaccine was assessed in the safety analysis set (ie, all participants who had received at least one injection, analysed according to the product received). This study is registered with WHO/ICTRP, number U111-1127-7162, and ClinicalTrials.gov, number NCT01887912, and has been terminated.

FINDINGS

Between July 30, 2013, and Nov 17, 2017, we enrolled and randomly assigned 9302 participants to the C difficile vaccine candidate group (n=6201) or to the placebo group (n=3101). 6173 (99·5%) participants in the C difficile vaccine candidate group and 3085 (99·5%) participants in the placebo group received at least one dose of the vaccine. The study was terminated after the first planned interim analysis because of futility. In the C difficile vaccine candidate group, 34 C difficile infections were reported over 11 697·2 person-years at risk (0·29 infections per 100 person-years [95% CI 0·20-0·41]) compared with 16 C difficile infections over 5789·4 person-years at risk in the placebo group (0·28 infections per 100 person-years [0·16-0·45]), indicating a vaccine efficacy of -5·2% (95% CI -104·1 to 43·5). In the C difficile vaccine candidate group, 2847 (46·6%) of 6113 participants reported an adverse event within 30 days of injection compared with 1282 (41·9%) of 3057 participants in the placebo group. The proportion of participants who had an adverse event leading to study discontinuation was 4·8% in both groups (296 participants in the C difficile vaccine candidate group and 146 participants in the placebo group). 1662 (27·2%) participants in the C difficile vaccine candidate group reported at least one serious adverse event compared with 851 (27·8%) participants in the placebo group.

INTERPRETATION

In adults at risk for C difficile infection, a bivalent C difficile toxoid vaccine did not prevent C difficile infection. Since the C difficile vaccine candidate met the criteria for futility, the study was terminated and clinical development of this vaccine candidate was stopped.

FUNDING

Sanofi Pasteur.

Molecular epidemiology of predominant and emerging Clostridioides difficile ribotypes

There has been an increase in the incidence and severity of Clostridioides difficile infection (CDI) worldwide, and strategies to control, monitor, and diminish the associated morbidity and mortality have been developed. Several typing methods have been used for typing of isolates and studying the epidemiology of CDI; serotyping was the first typing method, but then was replaced by pulsed-field gel electrophoresis (PFGE). PCR ribotyping is now the gold standard method; however, multi locus sequence typing (MLST) schemes have been developed. New sequencing technologies have allowed comparing whole bacterial genomes to address genetic relatedness with a high level of resolution and discriminatory power to distinguish between closely related strains. Here, we review the most frequent C. difficile ribotypes reported worldwide, with a focus on their epidemiology and genetic characteristics.

2407. Overexpression of Virulence Factors in Biofilm from Recurrent Clostridium (Clostridioides) difficile Infection Isolates

Background

Recurrent Clostridium (Clostridioides) difficile infection (R-CDI) remains a significant healthcare problem. Our aim was to analyze virulence/colonization determinants including spore formation, and expression of quorum sensing factors and adhesion capability in C. difficile biofilms, which serve as a potential reservoir for C. difficile in R-CDI.

Methods

Isolates obtained from patients with R-CDI (n = 39) and non-recurrent CDI (NR-CDI) (n = 93) were analyzed. Isolates were identified by PCR and MALDI-TOF MS and ribotyped by 16S-RNA amplification and capillary electrophoresis.

Biofilm production in a C. difficile and in a C. difficile-microbiota (Enterococcus and Lactobacillus species) model was assessed by the crystal violet method. Spore counts were determined both in planktonic and biofilm growth.

RNA was extracted from a selection of strains from R-CDI (n = 10) and NR-CDI (n = 10) isolate biofilms and relative expression levels of: spo0A, sigH, slpA, cwp84, agrD1 and luxS were determined.

Results

All NR-CDI and R-CDI isolates were biofilm producers and most were strongly adherent (90.90%) and 027 ribotype (81.37%).

In the C. difficile biofilm model, spore formation was higher in R-CDI than in the NR-CDI isolates (P = 0.015). In the biofilm of C. difficile-microbiota, no difference was detected in spore formation between the R-CDI and NR-CDI isolates (P = 0.677).

Expression of sigH (p = 0.007), spo0A (p = 0.003), cwp84 (p = 0.001) and agrD1 (p = 0.001) was higher in R-CDI than NR-CDI isolates. No difference was shown in slpA (p = 0.066) and luxS (p = 0.400) expression between groups.

Conclusion

Our data suggest that expression of sporulating pathway genes, sigH, spo0A, the quorum sensing gene, agrD₁; and adhesion-associated gene, cwp84 is higher in R-CDI isolates, in addition to elevated spore formation, which may have an impact on the recurrence of the infection.

Disclosures

All authors: No reported disclosures.

1789. Frequency of Chikungunya, Dengue, and Zika Virus in Acute Febrile Illness in Paired Urine and Serum Samples in Mexico

Background

Given the nonspecific clinical presentation that dengue (DENV), Zika (ZIKV), and chikungunya viruses (CHIKV) have, nucleic acid amplification tests have become the primary diagnostic tool. Multiplex real-time PCR assays have been approved for their use in the qualitative detection of ZIKV in urine but there are few data regarding CHIKV and DENV. We report the frequencies of PCR detection for DENV, ZIKV and CHIKV in paired urine and serum samples in Mexico.

Methods

We included patients with acute febrile illness from five centers, located in Guadalajara and Monterrey, from September 2016 to December 2018. Viral RNA was extracted from samples, reverse transcribed and subjected to real-time PCRs specific for DENV, CHIKV, and ZIKV. Patients were considered a positive case if any of the three tests were positive. The obtained data were analyzed using descriptive statistics.

Results

A total of 978 patients were included. A positive result was obtained in 331 patients (33.84%): 184 for ZIKV, 129 for DENV, and 18 for CHIKV. The tests were positive in both specimens in 56 (30.4%), 29 (22.4%), and 4 (22%) of the cases, respectively, while an isolated positive urine test was found in 74 (40%), 5 (3%) and 4 (22%) of the cases. Two patients were positive for both ZIKV and DENV, and two were positive for both ZIKV and CHIKV.

Conclusion

Acute febrile illness was potentially attributable to infection with one or two of the studied arboviruses in up to 34% of our patients. Out of all the cases, 25% were positive only in urine samples. Therefore, some diagnosis could be missed when analyzing only serum-based tests. Paired serum and urine sampling should be recommended when detecting arbovirus in acute febrile illness.

Disclosures

All authors: No reported disclosures.

2026. Phenotypic and Molecular Characterization of Drug Resistance and Biofilm Production in Stenotrophomonas maltophilia Obtained in a 10-Year Period from a Mexican Hospital

Background

Stenotrophomonas maltophilia is an emerging drug-resistant opportunistic pathogen related with healthcare-associated infections. The aim was to perform a phenotypic and molecular characterization of drug resistance and biofilm formation in S. maltophilia obtained in a 10-year period from a Mexican Hospital.

Methods

S. maltophilia isolates from a 10-year period from a tertiary care hospital in Mexico were identified by MALDI-TOF MS. Antimicrobial susceptibility was determined by the broth microdilution method. Drug resistance-associated genes were analyzed by PCR. Biofilm formation and its composition was assessed by crystal violet staining, and detachment assays, respectively. Biofilm production-associated genes were analyzed by PCR. MALDI-TOF mass spectra patterns were analyzed to search markers of drug resistance and biofilm production using the ClinProTools software.

Results

In the 10-year study period, 258 S. maltophilia isolates were identified, with high resistance detected for ceftazidime (48.4%), cefepime (31.6%), ciprofloxacin (25.0%), trimethoprim-sulfamethoxazole (18.8%), and lower resistance to chloramphenicol (13.6%) and levofloxacin (2.2%). Drug resistance was not associated to the presence of the sul1 (4.1%), sul2 (0.5%), sul3 (0.0%) or ISCR (0.0%) genes. Overexpression of the SmeABC efflux pump was associated to higher drug resistance (P < 0.05). Overall, 97.7% isolates were biofilm producers, i.e., 41.7% were strong producers; 32.0% were moderate, and 26.2% were weak producers. Biofilm composition analysis showed similar percentages for carbohydrates, proteins and DNA in all isolates (36.0, 39.7 and 40.9%, respectively). Biofilm-associated genes fsnR, rmlA, rpfF, xanB and spgM were detected in 94.0, 75.3, 28.6, 17.2% and 0.0% of isolates, respectively. Four potential biomarker peaks were detected in rmlA positive biofilm-producing isolates (P < 0.05).

Conclusion

Most of S. maltophilia clinical isolates showed high antimicrobial resistance levels and were able to produce biofilm. Biofilm biomass composition of these isolates showed a similar proportion of polysaccharides, proteins, and DNA. The presence of the rmlA gene was associated with biofilm production. Four potential markers of the presence of the biofilm production-associated rmlA gene were detected by mass spectrometry.

Disclosures

All authors: No reported disclosures.

New Delhi Metallo-Beta-Lactamase (NDM-1)-Producing Klebsiella Pneumoniae Isolated from a Burned Patient

Patient: Male, 32

Final Diagnosis: NDM-1-producing Klebsiella pneumoniae • bacteremia

Symptoms: Fever

Medication: —

Clinical Procedure: None

Specialty: Infectious Diseases

Current knowledge on the laboratory diagnosis of Clostridium difficile infection

Clostridium difficile (C. difficile) is a spore-forming, toxin-producing, gram-positive anaerobic bacterium that is the principal etiologic agent of antibiotic-associated diarrhea. Infection with C. difficile (CDI) is characterized by diarrhea in clinical syndromes that vary from self-limited to mild or severe. Since its initial recognition as the causative agent of pseudomembranous colitis, C. difficile has spread around the world. CDI is one of the most common healthcare-associated infections and a significant cause of morbidity and mortality among older adult hospitalized patients. Due to extensive antibiotic usage, the number of CDIs has increased. Diagnosis of CDI is often difficult and has a substantial impact on the management of patients with the disease, mainly with regards to antibiotic management. The diagnosis of CDI is primarily based on the clinical signs and symptoms and is only confirmed by laboratory testing. Despite the high burden of CDI and the increasing interest in the disease, episodes of CDI are often misdiagnosed. The reasons for misdiagnosis are the lack of clinical suspicion or the use of inappropriate tests. The proper diagnosis of CDI reduces transmission, prevents inadequate or unnecessary treatments, and assures best antibiotic treatment. We review the options for the laboratory diagnosis of CDI within the settings of the most accepted guidelines for CDI diagnosis, treatment, and prevention of CDI.

Mechanisms of Resistance, Clonal Expansion, and Increasing Prevalence of Acinetobacter baumannii Strains Displaying Elevated Tigecycline MIC Values in Latin America

The aim of the study was to characterize forty-eight Acinetobacter baumannii (ACB) isolates with confirmed tigecycline MIC values >2 mg/L observed in six Latin American (LATAM) hospitals (four countries) in 2011. During 2005-2011, 6,923 ACB isolates were collected as part of the SENTRY Program, and tigecycline susceptibility was quantified using the reference broth microdilution method. A total of 102/1881 ACB from LATAM hospitals displayed tigecycline minimum inhibitory concentration (MIC) values >2 mg/L, showing an increase from 4.3% in 2010 to 10.5% in 2011, which is considerably high when compared to other geographical regions. Forty-eight ACB from 2011 displaying elevated tigecycline MICs were typed by pulsed-field gel electrophoresis, which showed multiple clusters in Sao Paulo, Brazil, and a major clone in Guadalajara, Mexico. Eighteen unique isolates had the expression of adeA and adeF determined and results compared to a group of tigecycline-susceptible strains, which demonstrated that 18/18 strains had significantly increased expression of AdeABC and three isolates overexpressed AdeFGH. Sequencing of adeS and adeR revealed that 11 isolates displayed adeS mutations, and 5 isolates had mutations in adeR. Sequencing of trm showed frameshift mutations in eight isolates and insertion sequences leading to nonfunctional proteins in three isolates. TetX-encoding genes were not detected. We documented the recent increase of ACB displaying elevated tigecycline MICs in LATAM hospitals, dominantly due to the clonal expansion of isolates in Brazil and Mexico. Control of tigecycline usage in those countries and more strict infection control practices in the involved hospitals should be considered to reduce such outbreaks.

Antimicrobial susceptibility trends among gram-positive and -negative clinical isolates collected between 2005 and 2012 in Mexico: results from the Tigecycline Evaluation and Surveillance Trial

Background

The Tigecycline Evaluation and Surveillance Trial (T.E.S.T) is a global antimicrobial surveillance study of both gram-positive and gram-negative organisms. This report presents data on antimicrobial susceptibility among organisms collected in Mexico between 2005 and 2012 as part of T.E.S.T., and compares rates between 2005–2007 and 2008–2012.

Method

Each center in Mexico submitted at least 200 isolates per collection year; including 65 gram-positive isolates and 135 gram-negative isolates. Minimum inhibitory concentrations (MICs) were determined using Clinical Laboratory Standards Institute (CLSI) broth microdilution methodology and antimicrobial susceptibility was established using the 2013 CLSI-approved breakpoints. For tigecycline US Food and Drug Administration (FDA) breakpoints were applied. Isolates of E. coli and K. pneumoniae with a MIC for ceftriaxone of >1 mg/L were screened for ESBL production using the phenotypic confirmatory disk test according to CLSI guidelines.

Results

The rates of some key resistant phenotypes changed during this study: vancomycin resistance among Enterococcus faecium decreased from 28.6 % in 2005–2007 to 19.1 % in 2008–2012, while β-lactamase production among Haemophilus influenzae decreased from 37.6 to 18.9 %. Conversely, methicillin-resistant Staphylococcus aureus increased from 38.1 to 47.9 %, meropenem-resistant Acinetobacter spp. increased from 17.7 to 33.0 % and multidrug-resistant Acinetobacter spp. increased from 25.6 to 49.7 %. The prevalence of other resistant pathogens was stable over the study period, including extended-spectrum β-lactamase-positive Escherichia coli (39.0 %) and Klebsiella pneumoniae (25.0 %). The activity of tigecycline was maintained across the study years with MIC₉₀s of ≤2 mg/L against Enterococcus spp., S. aureus, Streptococcus agalactiae, Streptococcus pneumoniae, Enterobacter spp., E. coli, K. pneumoniae, Klebsiella oxytoca, Serratia marcescens, H. influenzae, and Acinetobacter spp. All gram-positive organisms were susceptible to tigecycline and susceptibility among gram-negatives ranged from 95.0 % for K. pneumoniae to 99.7 % for E. coli.

Conclusion

Antimicrobial resistance continues to be high in Mexico. Tigecycline was active against gram-positive and gram-negative organisms, including resistant phenotypes, collected during the study.

Clostridium difficile outbreak caused by NAP1/BI/027 strain and non-027 strains in a Mexican hospital

Background

Clostridium difficile infections caused by the NAP1/B1/027 strain are more severe, difficult to treat, and frequently associated with relapses.

Methods

A case–control study was designed to examine a C. difficile infection (CDI) outbreak over a 12-month period in a Mexican hospital. The diagnosis of toxigenic CDI was confirmed by real-time polymerase chain reaction, PCR (Cepheid Xpert C. difficile/Epi).

Results

During the study period, 288 adult patients were evaluated and 79 (27.4%) patients had confirmed CDI (PCR positive). C. difficile strain NAP1/B1/027 was identified in 31 (39%) of the patients with confirmed CDI (240 controls were included). Significant risk factors for CDI included any underlying disease (p < 0.001), prior hospitalization (p < 0.001), and antibiotic (p < 0.050) or steroid (p < 0.001) use. Laboratory abnormalities included leukocytosis (p < 0.001) and low serum albumin levels (p < 0.002). Attributable mortality was 5%. Relapses occurred in 10% of patients. Risk factors for C. difficile NAP1/B1/027 strain infections included prior use of quinolones (p < 0.03).

Risk factors for CDI caused by non-027 strains included chronic cardiac disease (p < 0.05), chronic renal disease (p < 0.009), and elevated serum creatinine levels (p < 0.003). Deaths and relapses were most frequent in the 027 group (10% and 19%, respectively).

Conclusions

C. difficile NAP1/BI/027 strain and non-027 strains are established pathogens in our hospital. Accordingly, surveillance of C. difficile infections is now part of our nosocomial prevention program.

Phenotypic and genotypic characterization of vancomycin-resistant Enterococcus faecium clinical isolates from two hospitals in Mexico: First detection of VanB phenotype-vanA genotype

INTRODUCTION

Enterococcus faecium has emerged as a multidrug-resistant nosocomial pathogen involved in outbreaks worldwide. Our aim was to determine the antimicrobial susceptibility, biofilm production, and clonal relatedness of vancomycin-resistant E. faecium (VREF) clinical isolates from two hospitals in Mexico.

METHODS

Consecutive clinical isolates (n=56) were collected in two tertiary care hospitals in Mexico from 2011 to 2014. VREF isolates were characterized by phenotypic and molecular methods including pulsed-field gel electrophoresis (PFGE).

RESULTS

VREF isolates were highly resistant to vancomycin, erythromycin, norfloxacin, high-level streptomycin, and teicoplanin, and showed lower resistance to tetracycline, nitrofurantoin and quinupristin-dalfopristin. None of the isolates were resistant to linezolid. The vanA gene was detected in all isolates. Two VanB phenotype-vanA genotype isolates, highly resistant to vancomycin and susceptible to teicoplanin, were detected. Furthermore, 17.9% of the isolates were classified as biofilm producers, and the espfm gene was found in 98.2% of the isolates. A total of 37 distinct PFGE patterns and 6 clones (25% of the isolates as clone A, 5.4% as clone B, and 3.6% each as clone C, D, E, and F) were detected. Clone A was detected in 5 different wards of the same hospital during 14 months of surveillance.

CONCLUSION

The high resistance to most antimicrobial agents and the moderate cross-transmission of VREF detected accentuates the need for continuous surveillance of E. faecium in the hospital setting. This is also the first reported incidence of the E. faecium VanB phenotype-vanA genotype in the Americas.

Epidemiology of Clostridium difficile: a hospital-based descriptive study in Argentina and Mexico

A prospective study was conducted in four tertiary hospitals in Argentina and Mexico in order to describe the occurrence of Clostridium difficile infection (CDI) in these settings. The objective was to evaluate the incidence of CDI in at-risk populations in Argentina (one center) and Mexico (three centers) and to further explore potential study sites for vaccine development in this region. A prospective, descriptive, CDI surveillance study was conducted among hospitalized patients aged ≥40 years who had received ≥48 h of antibiotic treatment. Stool samples were collected from those with diarrhea within 30 days after starting antibiotics and analyzed for toxins A and B by ELISA, and positive samples were further tested by toxinogenic culture and restriction endonuclease analysis type assay. Overall, 466 patients were enrolled (193 in Argentina and 273 in Mexico) of whom 414 completed the follow-up. Of these, 15/414 (3.6%) experienced CDI episodes occurring on average 18.1 days after admission to hospital and 15.9 days after the end of antibiotics treatment. The incidence rate of CDI was 3.1 (95% CI 1.7–5.2) per 1000 patient-days during hospitalization, and 1.1 (95% CI 0.6–1.8) per 1000 patient-days during the 30-day follow-up period. This study highlighted the need for further evaluation of the burden of CDI in both countries, including the cases occurring after discharge from hospital.

International Nosocomial Infection Control Consortium (INICC) report, data summary of 43 countries for 2007-2012. Device-associated module

We report the results of an International Nosocomial Infection Control Consortium (INICC) surveillance study from January 2007-December 2012 in 503 intensive care units (ICUs) in Latin America, Asia, Africa, and Europe. During the 6-year study using the Centers for Disease Control and Prevention's (CDC) U.S. National Healthcare Safety Network (NHSN) definitions for device-associated health care-associated infection (DA-HAI), we collected prospective data from 605,310 patients hospitalized in the INICC's ICUs for an aggregate of 3,338,396 days. Although device utilization in the INICC's ICUs was similar to that reported from ICUs in the U.S. in the CDC's NHSN, rates of device-associated nosocomial infection were higher in the ICUs of the INICC hospitals: the pooled rate of central line-associated bloodstream infection in the INICC's ICUs, 4.9 per 1,000 central line days, is nearly 5-fold higher than the 0.9 per 1,000 central line days reported from comparable U.S. ICUs. The overall rate of ventilator-associated pneumonia was also higher (16.8 vs 1.1 per 1,000 ventilator days) as was the rate of catheter-associated urinary tract infection (5.5 vs 1.3 per 1,000 catheter days). Frequencies of resistance of Pseudomonas isolates to amikacin (42.8% vs 10%) and imipenem (42.4% vs 26.1%) and Klebsiella pneumoniae isolates to ceftazidime (71.2% vs 28.8%) and imipenem (19.6% vs 12.8%) were also higher in the INICC's ICUs compared with the ICUs of the CDC's NHSN.

[QacEdelta1 gene frequency and biocide resistance in extended-spectrum beta-lactamase producing enterobacteriaceae clinical isolates]

OBJECTIVE

To determine the frequency of the gene qacEdelta1 and characterize the resistance to biocides of extended-spectrum beta-lactamases producing enterobacteriaceae (ESBL-PE) obtained from clinical isolates causing nosocomial infections.

MATERIAL AND METHODS

In total 59 ESBL-PE causing nosocomial infections were included: Klebsiella pneumoniae (35) and Enterobacter cloacae (24). Minimal inhibitory concentration (MIC) was tested for chlorhexidine (CHX) and benzalkonium chloride (CLBZ) by agar dilution technique. Amplification of the SHV, TLA-1 and qacEdelta1 genes were performed by PCR using specific primers and plasmid identification was done by alkaline lysis method. Matting experiments were obtained on solid agar method.

RESULTS

Chlorhexidine-resistance was found in 100% of the ESBL-PE and benzalkonium chloride-resistance in 80%. In 68% of the biocides-resistant strains the qacEdelta1 gene was present. The 66% of resulting transconjugants were resistant to CHX and the gene qacEdelta1 was detected in 55%.

CONCLUSIONS

The qacEdelta1 gene of antiseptic resistance is widespread in the EP-ESBL and can be transferred horizontally. Thus it is advisable to use combinations of antiseptics, as recommended in the literature, to avoid selection of multiresistant bacteria in hospitals, causing nosocomial infections.

Resistance trends in gram-negative bacteria: surveillance results from two Mexican hospitals, 2005-2010

BACKGROUND

Hospital-acquired infections caused by multiresistant gram-negative bacteria are difficult to treat and cause high rates of morbidity and mortality. The analysis of antimicrobial resistance trends of gram-negative pathogens isolated from hospital-acquired infections is important for the development of antimicrobial stewardship programs. The information obtained from antimicrobial resistant programs from two hospitals from Mexico will be helpful in the selection of empiric therapy for hospital-acquired gram-negative infections.

FINDINGS

Two thousand one hundred thirty two gram-negative bacteria collected between January 2005 and December 2010 from hospital-acquired infections occurring in two teaching hospitals in Mexico were evaluated. Escherichia coli was the most frequently isolated gram-negative bacteria, with >50% of strains resistant to ciprofloxacin and levofloxacin. Klebsiella spp. showed resistance rates similar to Escherichia coli for ceftazidime (33.1% vs 33.2%), but exhibited lower rates for levofloxacin (18.2% vs 56%). Of the samples collected for the third most common gram-negative bacteria, Pseudomonas aeruginosa, >12.8% were resistant to the carbapenems, imipenem and meropenem. The highest overall resistance was found in Acinetobacter spp. Enterobacter spp. showed high susceptibility to carbapenems.

CONCLUSIONS

E. coli was the most common nosocomial gram-negative bacilli isolated in this study and was found to have the second-highest resistance to fluoroquinolones (>57.9%, after Acinetobacter spp. 81.2%). This finding represents a disturbing development in a common nosocomial and community pathogen.

Isolation of rare coagulase-negative isolates in immunocompromised patients: Staphylococcus gallinarum, Staphylococcus pettenkoferi and Staphylococcus pasteuri

Herein, we describe the isolation of Staphylococcus pasteuri, Staphylococcus pettenkoferi and Staphylococcus gallinarum and summarize the clinical characteristics of five patients. Cases were identified over a 2-year surveillance period that identified the respective strains using microbiologic and molecular methods. These data suggest that rare coagulase-negative staphylococcal infections may be under-diagnosed due to difficulties associated with routine clinical laboratory diagnostic methods.

Changes in MIC within a global collection of Acinetobacter baumannii collected as part of the Tigecycline Evaluation and Surveillance Trial, 2004 to 2009

BACKGROUND

The Tigecycline Evaluation and Surveillance Trial (T.E.S.T.) began in 2004 to monitor global antimicrobial susceptibility to tigecycline and a range of comparator antimicrobials among gram-positive and gram-negative organisms.

OBJECTIVE

The aim of this study was to report changes in MIC for tigecycline and other antimicrobial agents among 10,149 Acinetobacter baumannii isolates collected globally between 2004 and 2009.

METHODS

MICs of 10,149 isolates were determined locally using Clinical Laboratory and Standards Institute (CLSI) methodologies. Antimicrobial susceptibility was ascertained according to CLSI interpretive criteria (no interpretive criteria have been approved for tigecycline against Acinetobacter spp).

RESULTS

Increases in resistance were noted for most antimicrobial agents in all regions. Significant (P < 0.05) increases in percentage resistance were reported for all antimicrobial agents globally. The smallest changes in cumulative geometric mean MICs were reported for tigecycline (0.2 mg/L) and cefepime (3.5 mg/L). MIC(90)s were at the top of their testing ranges for most agents against both multidrug-resistant (MDR) and non-MDR isolates; only tigecycline showed little change in MIC(90) between MDR (2 mg/L) and non-MDR (1 mg/L) isolates. Resistance was higher among isolates from the intensive care unit (ICU) compared with non-ICU isolates.

CONCLUSION

These findings suggest that resistance is increasing among clinical isolates of A baumannii globally. Although resistance to tigecycline has been reported in the treatment of infections caused by A baumannii, it retains in vitro activity against this pathogen.

Microbiological and molecular characterization of human clinical isolates of Staphylococcus cohnii, Staphylococcus hominis, and Staphylococcus sciuri

BACKGROUND

The incidence of coagulase-negative staphylococci reported as causative agents of nosocomial infections has risen in the last decade. The aim of this study was to characterize biofilm formation, antibiotic resistance, SCCmec type, and genetic relatedness in clinical isolates of Staphylococcus cohnii, Staphylococcus hominis, and Staphylococcus sciuri recovered from humans.

METHODS

Clinically relevant isolates of S. cohnii (n = 15), S. hominis (n = 9), and S. sciuri (n = 6), were collected from patients. Biofilm formation was evaluated using crystal violet staining, drug susceptibility was assessed using the broth microdilution method, and methicillin resistance was measured using the cefoxitin disk test. SCCmec was typed using 2 different methodologies, and genetic relatedness was determined by pulsed-field gel electrophoresis (PFGE).

RESULTS

Sixty percent (9/15) of S. cohnii, 33% (3/9) of S. hominis, and 50% (3/6) of S. sciuri isolates were categorized as weak producers of biofilm. None of the isolates were resistant to vancomycin or linezolid. All 3 species showed a high resistance (> 66%) to ampicillin, levofloxacin, erythromycin, and ceftriaxone, and the majority of the isolates were methicillin-resistant. PFGE revealed that the S. cohnii isolates comprised 1 dominant clone.

CONCLUSIONS

The S. cohnii, S. hominis, and S. sciuri isolates analyzed in this study showed a high methicillin resistance and resistance to other antimicrobials. The results of this study strongly suggest that coagulase-negative staphylococci harbour new SCCmec elements. We report the first case of a clone of S. cohnii associated with human disease.

Acceptance of a vaccine against novel influenza A (H1N1) virus among health care workers in two major cities in Mexico

BACKGROUND AND AIMS

Further cases of novel influenza A (H1N1) outbreak are expected in the coming months. Vaccination has been proven to be essential to control a pandemic of influenza; therefore, considerable efforts and resources have been devoted to develop a vaccine against the influenza A (H1N1) virus. With the current availability of the vaccine, it will be important to immunize as many people as possible. However, previous data with seasonal influenza vaccines have shown that there are multiple barriers related to perceptions and attitudes of the population that influence vaccine use. The aim of the study was to evaluate the acceptance of a newly developed vaccine against pandemic (H1N1) 2009 influenza A among healthcare workers (HCW) in Mexico.

METHODS

We conducted a cross-sectional study among HCW in three hospitals in the two largest cities in Mexico-Mexico City and Guadalajara-between June and September 2009.

RESULTS

A total of 1097 HCW participated in the survey. Overall, 80% (n = 880) intended to accept the H1N1 pandemic vaccine and 71.6% (n = 786) reported they would recommend the vaccine to their patients. Doctors were more likely to accept and recommend the vaccine than nurses. HCWs who intend to be immunized will be more likely to do so if they know that the vaccine is safe and effective.

CONCLUSIONS

Knowledge of the willingness to accept the vaccine can be used to plan strategies that will effectively respond to the needs of the population studied, reducing the health and economic impact of novel influenza A (H1N1) virus.

Hospital triage system for adult patients using an influenza-like illness scoring system during the 2009 pandemic--Mexico

BACKGROUND

Pandemic influenza A (H1N1) virus emerged during 2009. To help clinicians triage adults with acute respiratory illness, a scoring system for influenza-like illness (ILI) was implemented at Hospital Civil de Guadalajara, Mexico.

METHODS

A medical history, laboratory and radiology results were collected on emergency room (ER) patients with acute respiratory illness to calculate an ILI-score. Patients were evaluated for admission by their ILI-score and clinicians' assessment of risk for developing complications. Nasal and throat swabs were collected from intermediate and high-risk patients for influenza testing by RT-PCR. The disposition and ILI-score of those oseltamivir-treated versus untreated, clinical characteristics of 2009 pandemic influenza A (H1N1) patients versus test-negative patients were compared by Pearson's Chi(2), Fisher's Exact, and Wilcoxon rank-sum tests.

RESULTS

Of 1840 ER patients, 230 were initially hospitalized (mean ILI-score = 15), and the rest were discharged, including 286 ambulatory patients given oseltamivir (median ILI-score = 11), and 1324 untreated (median ILI-score = 5). Fourteen (1%) untreated patients returned, and 3 were hospitalized on oseltamivir (median ILI-score = 19). Of 371 patients tested by RT-PCR, 104 (28%) had pandemic influenza and 42 (11%) had seasonal influenza A detected. Twenty (91%) of 22 imaged hospitalized pandemic influenza patients had bilateral infiltrates compared to 23 (38%) of 61 imaged hospital test-negative patients (p<0.001). One patient with confirmed pandemic influenza presented 6 days after symptom onset, required mechanical ventilation, and died.

CONCLUSIONS

The triaging system that used an ILI-score complimented clinicians' judgment of who needed oseltamivir and inpatient care and helped hospital staff manage a surge in demand for services.

Comparison of the efficacy and safety of isepamicin and amikacin in the treatment of skin and skin structure infections

Two hundred and three patients with skin and skin structure infections were treated with isepamicin once daily or amikacin twice daily in an open, randomised, comparative multicentre trial. Patients were randomised to treatment with isepamicin or amikacin in a 2:1 ratio. Severe infections (63 patients) were treated with isepamicin 15 mg/kg once daily (n = 15) or amikacin 7.5 mg/kg twice daily (n - 18), less severe infections (140 patients) with isepamicin 8 mg/kg once daily (n = 93) or amikacin 7.5 mg/kg twice daily (n = 47). The overall clinical response rate at the end of treatment was excellent in all treatment groups (94-96% cured or improved) with no significant differences between isepamicin and amikacin in patients with either server or less severe infections. The most commonly isolated target pathogens were Pseudomonas aeruginosa, Escherichia coli, Proteus mirabilis and Staphylococcus aureus. Overall, in patients who had a valid target pathogen isolated prior to treatment and who met other evaluability criteria, bacteriological eradication was achieved in over 90% of patients; amikacin patients with severe infections had a somewhat lower eradication rate (82%). Over all infections, 4/110 (4%) patients in the isepamicin group and 5/54 (9%) patients in the amikacin had organisms which persisted. Adverse events were reported in 12% of patients in the isepamicin group and 6% in the amikacin group. The most frequently reported adverse event in the isepamicin group as headache. Two patients (one in each treatment group), both of whom experienced skin rashes, were withdrawn. Potentially clinically significant changes in serum creatinine occurred in two patients, who received isepamicin and one who received amikacin (who was withdrawn from the study). Ototoxicity was rare, occurring in one patient treated with isepamicin.

The use of quinolones in developing countries

The size of the antibiotic market in developing countries is double that seen in developed countries. There are some valid reasons for this difference, one of which is the higher frequency of diverse infections in the developing world. However, other factors are involved: for example, antibiotics are available without prescription, package insert information is poor, and there is no national antibiotic usage programme, all of which encourage inappropriate antibacterial use. When an antibiotic becomes widely prescribed by physicians, this is interpreted by the general public as meaning that the antibiotic is useful for all types of infections and the process of automedication begins. The newer quinolones, other new antibiotics, and indeed all antimicrobials should be available only by prescription. A package insert that includes all pertinent information should be provided, and each country should implement a comprehensive national antibiotic usage programme. Only through these measures will bacterial resistance be controlled and the effectiveness of each antibiotic class be maintained.

Comparison of the safety and efficacy of lomefloxacin and trimethoprim/sulfamethoxazole in the treatment of uncomplicated urinary tract infections: results from a multicenter study

Lomefloxacin, a new difluorinated quinolone, and trimethoprim/sulfamethoxazole (TMP/SMX) were compared in the treatment of adults with uncomplicated urinary tract infections. The study was conducted as a multicenter, controlled, prospectively randomized, single-blind study in five countries (Argentina, Belgium, Brazil, Mexico, and Venezuela). A total of 254 patients were enrolled: 129 in the lomefloxacin group and 125 in the TMP/SMX group. Patients received either 400 mg lomefloxacin orally once daily or 160 mg/800 mg TMP/SMX orally twice daily for 7-10 days. Escherichia coli and Proteus mirabilis were the pathogens most frequently isolated. At 5-9 days post-therapy, satisfactory bacteriologic results were noted in 98.4% of patients treated with lomefloxacin and in 95.8% of patients in the TMP/SMX group (p = 0.2153). Clinical success 5-9 days post-therapy was noted in 99.2% of patients in the lomefloxacin group and in 98.3% of patients in the TMP/SMX group (p = 0.5138). Adverse events probably related to treatment occurred in 6% of those treated with lomefloxacin and in 7% of patients treated with TMP/SMX. Once-daily oral lomefloxacin is a well-tolerated and effective treatment of uncomplicated urinary tract infections caused by susceptible pathogens.