The burden of antimicrobial resistance in the Americas in 2019: a cross-country systematic analysis

Background

Antimicrobial resistance (AMR) is an urgent global health challenge and a critical threat to modern health care. Quantifying its burden in the WHO Region of the Americas has been elusive-despite the region's long history of resistance surveillance. This study provides comprehensive estimates of AMR burden in the Americas to assess this growing health threat.

Methods

We estimated deaths and disability-adjusted life-years (DALYs) attributable to and associated with AMR for 23 bacterial pathogens and 88 pathogen-drug combinations for countries in the WHO Region of the Americas in 2019. We obtained data from mortality registries, surveillance systems, hospital systems, systematic literature reviews, and other sources, and applied predictive statistical modelling to produce estimates of AMR burden for all countries in the Americas. Five broad components were the backbone of our approach: the number of deaths where infection had a role, the proportion of infectious deaths attributable to a given infectious syndrome, the proportion of infectious syndrome deaths attributable to a given pathogen, the percentage of pathogens resistant to an antibiotic class, and the excess risk of mortality (or duration of an infection) associated with this resistance. We then used these components to estimate the disease burden by applying two counterfactual scenarios: deaths attributable to AMR (compared to an alternative scenario where resistant infections are replaced with susceptible ones), and deaths associated with AMR (compared to an alternative scenario where resistant infections would not occur at all). We generated 95% uncertainty intervals (UIs) for final estimates as the 25th and 975th ordered values across 1000 posterior draws, and models were cross-validated for out-of-sample predictive validity.

Findings

We estimated 569,000 deaths (95% UI 406,000-771,000) associated with bacterial AMR and 141,000 deaths (99,900-196,000) attributable to bacterial AMR among the 35 countries in the WHO Region of the Americas in 2019. Lower respiratory and thorax infections, as a syndrome, were responsible for the largest fatal burden of AMR in the region, with 189,000 deaths (149,000-241,000) associated with resistance, followed by bloodstream infections (169,000 deaths [94,200-278,000]) and peritoneal/intra-abdominal infections (118,000 deaths [78,600-168,000]). The six leading pathogens (by order of number of deaths associated with resistance) were Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, Streptococcus pneumoniae, Pseudomonas aeruginosa, and Acinetobacter baumannii. Together, these pathogens were responsible for 452,000 deaths (326,000-608,000) associated with AMR. Methicillin-resistant S. aureus predominated as the leading pathogen-drug combination in 34 countries for deaths attributable to AMR, while aminopenicillin-resistant E. coli was the leading pathogen-drug combination in 15 countries for deaths associated with AMR.

Interpretation

Given the burden across different countries, infectious syndromes, and pathogen-drug combinations, AMR represents a substantial health threat in the Americas. Countries with low access to antibiotics and basic health-care services often face the largest age-standardised mortality rates associated with and attributable to AMR in the region, implicating specific policy interventions. Evidence from this study can guide mitigation efforts that are tailored to the needs of each country in the region while informing decisions regarding funding and resource allocation. Multisectoral and joint cooperative efforts among countries will be a key to success in tackling AMR in the Americas.

Funding

Bill & Melinda Gates Foundation, Wellcome Trust, and Department of Health and Social Care using UK aid funding managed by the Fleming Fund.

Safety and Tolerability of Six Months of Isoniazid Plus Pyridoxine or Three Months of Rifampicin for Tuberculosis among Subjects with Diabetes Mellitus: A Randomized Trial

Tuberculosis (TB) associated with diabetes mellitus (DM) is a growing problem, particularly in low- and medium-resource countries. We conducted an open-label, parallel-group, randomized, and controlled trial in a tertiary care center in Mexico City to assess TB preventive treatment (TPT) with isoniazid (INH) or rifampicin (RIF) in people with type 2 DM. Participants were assigned six months of INH 300 mg/day plus pyridoxine 75 mg or three months of RIF 600 mg/day. The primary outcomes were adverse events resulting in permanent treatment cessation and considered possibly or probably related to study drugs. We included 130 subjects, 68 randomized to INH and 62 to RIF. We prematurely halted the study based on recommendations of the Adverse Event Safety Panel. There was no difference between arms in the overall frequency of adverse events. However, the INH group had significantly more permanent treatment interruptions due to grade 2 recurrent or grade 3 or 4 hepatoxicity. In comparison, the RIF arm had more treatment interruptions due to grade 3 or 4 gastrointestinal intolerance. TPT using INH or RIF is not safe enough to be considered a universal indication to patients with type 2 DM and TB infection. These results underline the need to search for alternative TB preventions with better safety profiles for type 2 DM patients.

Predictors of Mortality in Patients with Infections Due to Carbapenem-Resistant Gram-Negative Bacteria

INTRODUCTION

Infections caused by carbapenem-resistant Gram-negative bacteria (CR-GNB) are a significant cause of mortality and represent a serious challenge to health systems. The early identification of mortality predictors could guide appropriate treatment and follow-up. We aimed to identify the factors associated with 90-day all-cause mortality in patients with CR-GNB infections.

METHODS

We conducted a cohort study from 1 January 2019 to 30 April 2022. The primary outcome was death from any cause during the first 90 days after the date of the first CR-GNB-positive culture. Secondary outcomes included infection relapse, invasive mechanical ventilation during follow-up, need for additional source control, acute kidney injury, Clostridioides difficile infection, and all-cause hospital admission after initial discharge. Bivariate and multivariate Cox-proportional hazards models were constructed to identify the factors independently associated with 90-day all-cause mortality.

RESULTS

A total of 225 patients with CR-GNB infections were included. Death occurred in 76 (34%) cases. The most-reported comorbidities were immunosuppression (43%), arterial hypertension (35%), and COVID-19 (25%). The median length of stay in survivors was 18 days (IQR 10-34). Mechanical ventilation and ICU admission after diagnosis occurred in 8% and 11% of cases, respectively. Both infection relapse and rehospitalisation occurred in 18% of cases. C. difficile infection was diagnosed in 4% of cases. Acute kidney injury was documented in 22% of patients. Mechanical ventilation after diagnosis, ICU admission after diagnosis, and acute kidney injury in the first ten days of appropriate treatment were more frequently reported among non-survivors. In the multivariate analysis, age (HR 1.19 (95%CI 1.00-1.83)), immunosuppression (HR 1.84 (95%CI 1.06-3.18)), and septic shock at diagnosis (HR 2.40 (95% 1.41-4.08)) had an independent association with death during the first 90 days after the CR-GNB infection diagnosis. Receiving antibiogram-guided appropriate treatment was independently associated with a lower risk of death (HR 0.25 (95%CI 0.14-0.46)).

CONCLUSIONS

The presence of advanced age, immunosuppression, septic shock at diagnosis, and inappropriate treatment are associated with higher 90-day all-cause mortality in hospitalised patients with infections due to CR-GNB. Recognition of the risk factors for adverse outcomes could further assist in patient care and the design of interventional studies that address the severe and widespread problem that is carbapenem resistance.

Risk Factors Associated with the Development of Hospital-Acquired Infections in Hospitalized Patients with Severe COVID-19

Recognition of risk factors for hospital-acquired infections (HAI) in patients with COVID-19 is warranted. We aimed to describe factors associated with the development of HAI in patients with severe COVID-19. We conducted a retrospective cohort study including all adult patients admitted with severe COVID-19 between March 2020 and November 2020. The primary outcome was HAI development. Bivariate and multiple logistic regression models were constructed. Among 1540 patients, HAI occurred in 221 (14%). A total of 299 episodes of HAI were registered. The most common HAI were hospital-acquired/ventilation-associated pneumonia (173 episodes) and primary bloodstream infection (66 episodes). Death occurred in 387 (35%) patients and was more frequent in patients with HAI (38% vs. 23%, p < 0.01). Early mechanical ventilation (aOR 18.78, 95% CI 12.56-28.07), chronic kidney disease (aOR 3.41, 95% CI 1.4-8.27), use of corticosteroids (aOR 2.95, 95% CI 1.92-4.53) and tocilizumab (aOR 2.68, 95% CI 1.38-5.22), age ≥ 60 years (aOR 1.91, 95% CI 1.27-2.88), male sex (aOR 1.52, 95% CI 1.03-2.24), and obesity (aOR 1.49, 95% CI 1.03-2.15) were associated with HAI. In patients with severe COVID-19, mechanical ventilation within the first 24 h upon admission, chronic kidney disease, use of corticosteroids, use of tocilizumab, age ≥ 60 years, male sex, and obesity were associated with a higher risk of HAI.

Global burden of bacterial antimicrobial resistance in 2019: a systematic analysis

BACKGROUND

Antimicrobial resistance (AMR) poses a major threat to human health around the world. Previous publications have estimated the effect of AMR on incidence, deaths, hospital length of stay, and health-care costs for specific pathogen-drug combinations in select locations. To our knowledge, this study presents the most comprehensive estimates of AMR burden to date.

METHODS

We estimated deaths and disability-adjusted life-years (DALYs) attributable to and associated with bacterial AMR for 23 pathogens and 88 pathogen-drug combinations in 204 countries and territories in 2019. We obtained data from systematic literature reviews, hospital systems, surveillance systems, and other sources, covering 471 million individual records or isolates and 7585 study-location-years. We used predictive statistical modelling to produce estimates of AMR burden for all locations, including for locations with no data. Our approach can be divided into five broad components: number of deaths where infection played a role, proportion of infectious deaths attributable to a given infectious syndrome, proportion of infectious syndrome deaths attributable to a given pathogen, the percentage of a given pathogen resistant to an antibiotic of interest, and the excess risk of death or duration of an infection associated with this resistance. Using these components, we estimated disease burden based on two counterfactuals: deaths attributable to AMR (based on an alternative scenario in which all drug-resistant infections were replaced by drug-susceptible infections), and deaths associated with AMR (based on an alternative scenario in which all drug-resistant infections were replaced by no infection). We generated 95% uncertainty intervals (UIs) for final estimates as the 25th and 975th ordered values across 1000 posterior draws, and models were cross-validated for out-of-sample predictive validity. We present final estimates aggregated to the global and regional level.

FINDINGS

On the basis of our predictive statistical models, there were an estimated 4·95 million (3·62-6·57) deaths associated with bacterial AMR in 2019, including 1·27 million (95% UI 0·911-1·71) deaths attributable to bacterial AMR. At the regional level, we estimated the all-age death rate attributable to resistance to be highest in western sub-Saharan Africa, at 27·3 deaths per 100 000 (20·9-35·3), and lowest in Australasia, at 6·5 deaths (4·3-9·4) per 100 000. Lower respiratory infections accounted for more than 1·5 million deaths associated with resistance in 2019, making it the most burdensome infectious syndrome. The six leading pathogens for deaths associated with resistance (Escherichia coli, followed by Staphylococcus aureus, Klebsiella pneumoniae, Streptococcus pneumoniae, Acinetobacter baumannii, and Pseudomonas aeruginosa) were responsible for 929 000 (660 000-1 270 000) deaths attributable to AMR and 3·57 million (2·62-4·78) deaths associated with AMR in 2019. One pathogen-drug combination, meticillin-resistant S aureus, caused more than 100 000 deaths attributable to AMR in 2019, while six more each caused 50 000-100 000 deaths: multidrug-resistant excluding extensively drug-resistant tuberculosis, third-generation cephalosporin-resistant E coli, carbapenem-resistant A baumannii, fluoroquinolone-resistant E coli, carbapenem-resistant K pneumoniae, and third-generation cephalosporin-resistant K pneumoniae.

INTERPRETATION

To our knowledge, this study provides the first comprehensive assessment of the global burden of AMR, as well as an evaluation of the availability of data. AMR is a leading cause of death around the world, with the highest burdens in low-resource settings. Understanding the burden of AMR and the leading pathogen-drug combinations contributing to it is crucial to making informed and location-specific policy decisions, particularly about infection prevention and control programmes, access to essential antibiotics, and research and development of new vaccines and antibiotics. There are serious data gaps in many low-income settings, emphasising the need to expand microbiology laboratory capacity and data collection systems to improve our understanding of this important human health threat.

FUNDING

Bill & Melinda Gates Foundation, Wellcome Trust, and Department of Health and Social Care using UK aid funding managed by the Fleming Fund.

317. Invasive Fungal Infections in Critically-ill Patients with COVID-19 in Mexico City

Background

Invasive fungal infections (IFI) are emergent complications in SARS-CoV-2 infection. We aimed to describe the epidemiology, characteristics and outcome of IFI during the pandemic.

Methods

Between March 2020 and April 2021, patients admitted to the Intensive Care Unit (ICU) in a COVID-19 center in Mexico City who developed IFI were included. COVID-19 associated pulmonary aspergillosis (CAPA) was defined according to the ECMM/ISHAM criteria. Demographic and clinical data were obtained from the electronic medical record. Descriptive analysis was made. The study was approved by the Institutional Review Board.

Results

Sixty-seven (67/743, 9%) patients with COVID-19 developed IFI during ICU stay, of which 37 (55%) had CAPA, 24 (36%) had Invasive Candidiasis (IC), 3 Cryptococcosis and 3 pulmonary Mucormycosis. The median age was 57.5 (IQR 48-68) and 46 (69%) were male. Thirty-six (54%) had obesity and 20 (30%) type 2 diabetes. Sixty-two received COVID-19 directed therapy: 48/67 (72%) steroids, 4/67 (6%) tocilizumab and 8/67 (12%) were included in clinical trials. Among 24 patients with IC, 13 (54%) were fluconazole-resistant C. parapsilosis, 11 (46%) C. albicans and 2 C. glabrata. Twenty-two received antifungal treatment, 20 with echinocandins and 2 fluconazole. Among 37 CAPA, 8 (22%) were probable and 29 (78%) possible. Serum galactomannan was positive in 8 (22%), 33 respiratory cultures grew Aspergillus (31 tracheal aspirates and 2 bronchoalveolar lavage). Aspergillus fumigatus was the most frequent isolate in 18/33 (55%). Chest CT showed ground glass opacities in 21 (57%). Most received voriconazole (26/37, 70%). The median time from ICU admission to IFI was 9.5 (IQR 3-14) days. The median ICU and hospital stay length were 30 days (IQR 16-41) and 40 days (IQR 23-49), respectively. In-hospital mortality was 48%. The incidence rate of IC was higher early in the pandemic, due to Infection Control breaches, while higher CAPA incidence may have occurred later due to ventilation system gaps (Figure 1).

Bi-monthly Invasive Fungal Infection incidence rate/100 ICU admissions.

Conclusion

We found 9% incidence of IFIs in critically-ill COVID-19 patients with high mortality. The majority received steroids, had obesity and had a prolonged hospital stay. Most had possible CAPA. An outbreak of fluconazole-resistant C. parapsilosis was found.

Disclosures

All Authors: No reported disclosures

Outcomes of patients with severe and critical COVID-19 treated with dexamethasone: a prospective cohort study

Dexamethasone implementation for COVID-19 management represented a milestone but data regarding its impact and safety have not been consistently reproduced. We aimed to evaluate in-hospital mortality before and after the implementation of corticosteroid treatment (CS-T) for severe and critical COVID-19. We conducted a cohort study that included patients admitted with severe and critical COVID-19. The primary outcome was death during hospitalization. Secondary outcomes included the length of stay (LOS), need for invasive mechanical ventilation (IMV), time to IMV initiation, IMV duration, and development of hospital-acquired infections (HAIs). Bivariate, multivariate, and propensity-score matching analysis were performed. Among 1540 patients, 688 (45%) received CS-T. Death was less frequent in the CS-T group (18 vs 31%, p < .01). Among patients on IMV, death was also less frequent in the CS-T group (25 vs 55%, p < .01). The median time to IMV was longer in the CS-T group (5 vs 3 days, p < .01). HAIs occurred more frequently in the CS-T group (20 vs 10%, p < .01). LOS, IMV, and IMV duration were similar between groups. Multivariate analysis revealed an independent association between CS-T and lower mortality (aOR 0.26, 95% CI 0.19-0.36, p < .001). Propensity-score matching analysis revealed that CS-T was independently associated with lower mortality (aOR 0.33, 95% CI 0.22-0.50, p < .01). Treatment with corticosteroids was associated with reduced in-hospital mortality among patients with severe and critical COVID-19, including those on IMV.

Accuracy of galactomannan testing on tracheal aspirates in COVID-19-associated pulmonary aspergillosis

Objective

Our aim was to evaluate the performance of two galactomannan (GM) assays (Platelia Aspergillus EIA, Bio‐Rad^®, and Aspergillus GM LFA, IMMY^®) in tracheal aspirate (TA) samples of consecutive critically ill patients with COVID‐19.

Methods

We included critically ill patients, performed GM‐EIA and GM‐Lateral Flow Assay (GM‐LFA) in TA and followed them until development of COVID‐19‐associated pulmonary aspergillosis (CAPA) or alternate diagnosis. CAPA was defined according to the modified AspICU criteria in patients with SARS‐CoV‐2 infection. We estimated sensitivity, specificity, positive and negative predictive values for GM‐EIA, GM‐LFA, the combination of both or either positive results for GM‐EIA and GM‐LFA. We explored accuracy using different breakpoints, through ROC analysis and Youden index to identify the optimal cut‐offs. We described antifungal treatment and 30‐day mortality.

Results

We identified 14/144 (9.7%) patients with CAPA, mean age was 50.35 (SD 11.9), the median time from admission to CAPA was 8 days; 28.5% received tocilizumab and 30‐day mortality was 57%. ROC analysis and Youden index identified 2.0 OD as the best cut‐off, resulting in sensitivity and specificity of 57.1% and 81.5% for GM‐EIA and 60% and 72.6% for GM‐LFA, respectively.

Conclusions

The diagnostic performance of GM in tracheal aspirates improved after using a cut‐off of 2 OD. Although bronchoalveolar lavage testing is the ideal test, centres with limited access to bronchoscopy may consider this approach to identify or rule out CAPA.

Antimicrobial Resistance Patterns and Antibiotic Use during Hospital Conversion in the COVID-19 Pandemic

OBJECTIVE

To describe empirical antimicrobial prescription on admission in patients with severe COVID-19, the prevalence of Hospital-Acquired Infections, and the susceptibility patterns of the causing organisms.

METHODS

In this prospective cohort study in a tertiary care center in Mexico City, we included consecutive patients admitted with severe COVID-19 between March 20th and June 10th and evaluated empirical antimicrobial prescription and the occurrence of HAI.

RESULTS

794 patients with severe COVID-19 were admitted during the study period. Empiric antibiotic treatment was started in 92% of patients (731/794); the most frequent regimes were amoxicillin-clavulanate plus atypical coverage in 341 (46.6%) and ceftriaxone plus atypical coverage in 213 (29.1%). We identified 110 HAI episodes in 74/656 patients (11.3%). Ventilator-associated pneumonia (VAP) was the most frequent HAI, in 56/110 (50.9%), followed by bloodstream infections (BSI), in 32/110 (29.1%). The most frequent cause of VAP were Enterobacteriaceae in 48/69 (69.6%), followed by non-fermenter gram-negative bacilli in 18/69 (26.1%). The most frequent cause of BSI was coagulase negative staphylococci, in 14/35 (40.0%), followed by Enterobacter complex in 7/35 (20%). Death occurred in 30/74 (40.5%) patients with one or more HAI episodes and in 193/584 (33.0%) patients without any HAI episode (p < 0.05).

CONCLUSION

A high frequency of empiric antibiotic treatment in patients admitted with COVID-19 was seen. VAP and BSI were the most frequent hospital-acquired infections, due to Enterobacteriaceae and coagulase negative staphylococci, respectively.

Impact of undiagnosed type 2 diabetes and pre-diabetes on severity and mortality for SARS-CoV-2 infection

INTRODUCTION

Diabetes and hyperglycemia are risk factors for critical COVID-19 outcomes; however, the impact of pre-diabetes and previously unidentified cases of diabetes remains undefined. Here, we profiled hospitalized patients with undiagnosed type 2 diabetes and pre-diabetes to evaluate its impact on adverse COVID-19 outcomes. We also explored the role of de novo and intrahospital hyperglycemia in mediating critical COVID-19 outcomes.

RESEARCH DESIGN AND METHODS

Prospective cohort of 317 hospitalized COVID-19 cases from a Mexico City reference center. Type 2 diabetes was defined as previous diagnosis or treatment with diabetes medication, undiagnosed diabetes and pre-diabetes using glycosylated hemoglobin (HbA1c) American Diabetes Association (ADA) criteria and de novo or intrahospital hyperglycemia as fasting plasma glucose (FPG) ≥140 mg/dL. Logistic and Cox proportional regression models were used to model risk for COVID-19 outcomes.

RESULTS

Overall, 159 cases (50.2%) had type 2 diabetes and 125 had pre-diabetes (39.4%), while 31.4% of patients with type 2 diabetes were previously undiagnosed. Among 20.0% of pre-diabetes cases and 6.1% of normal-range HbA1c had de novo hyperglycemia. FPG was the better predictor for critical COVID-19 compared with HbA1c. Undiagnosed type 2 diabetes (OR: 5.76, 95% CI 1.46 to 27.11) and pre-diabetes (OR: 4.15, 95% CI 1.29 to 16.75) conferred increased risk of severe COVID-19. De novo/intrahospital hyperglycemia predicted critical COVID-19 outcomes independent of diabetes status.

CONCLUSIONS

Undiagnosed type 2 diabetes, pre-diabetes and de novo hyperglycemia are risk factors for critical COVID-19. HbA1c must be measured early to adequately assess individual risk considering the large rates of undiagnosed type 2 diabetes in Mexico.

459. Outcomes and Factors Associated with a SARS-CoV-2 Positive Test in Asymptomatic and Symptomatic Healthcare Workers of a Mexican Hospital Converted to Treat COVID-19 Patients

Background

Starting on 03/16/2020, the hospital was converted to attend only patients with COVID-19. A surveillance program for healthcare workers (HCWs) that included free in-site medical consultation and RT-PCR for detection of SARS-CoV-2 was initiated. On 04/28/2020, screening of HCWs was started to detect asymptomatic carriers. We report the results of such programs updated to 05/21/2020.

Methods

Sex, worker category, working area, use of personal protective equipment, date of screening, date of onset of symptoms and home address were retrieved from electronic databases. Logistic regression was done to identify factors associated with being a COVID-19 case or carrier, with p&lt; 0.05 being significant. Odds ratios and incidence densities were calculated.

Results

Of 2566 HCWs in the hospital, 976 (38.0%) underwent screening and 41 (4.2%) were positive for SARS-CoV-2 (7.4 carriers x 10,000 person-days; median follow-up of 55.5 days); none of the latter were diagnosed with COVID-19 after completing a 14-day follow-up. Of HCWs with negative screen results, 6 (0.6%) ultimately developed COVID-19 after a median of 10 days (1.1 cases x 10,000 person-days). Of 232 symptomatic HCWs that did not undergo basal screening, 131 (56.5%) were diagnosed with COVID-19 (8.8 cases x 10,000 person-days). Ten COVID-19 cases (7.6%) were hospitalized and all were discharged without complications after a median hospital stay of 9 days. Factors associated with COVID-19 were working in a non-clinical area (OR=9.3, 95% CI=1.1–78.6) and being a nurse (OR=1.9, 95% CI=1.1–3.4). Factors associated with being a carrier were living in the State of Mexico (OR=3.7, 95% CI=1.8–8.0) and being a hospital cook (OR=3.7, 95% CI=1.7–8.5). Being a physician was associated with not being a carrier (OR=0.07, 95% CI=0.01–0.5). Wearing a face mask at all times tended to be associated with not being a carrier. Hospital epidemic curves closely ressembled those of the community (Mexico City).

Hospital Epidemic Curve, 03/16/2020 - 05/21/2020

Conclusion

This study suggests that factors present inside and outside of the hospital are associated with COVID-19 and asymptomatic carriage in HCWs. This information is of utmost importance for infection prevention and control policies. Additionally, a lower percentage of severe cases and no deaths were observed in this cohort as compared to others.

Disclosures

All Authors: No reported disclosures

The influence of hospital antimicrobial use on carbapenem-non-susceptible Enterobacterales incidence rates according to their mechanism of resistance: a time-series analysis

BACKGROUND

Carbapenem non-susceptible Enterobacterales (CNSE) can be broadly divided into those that produce carbapenemases (carbapenemase-producing Enterobacterales (CPE)), and those that harbour other mechanisms of resistance (non-carbapenemase-producing CNSE (NCP-CNSE)).

AIM

To determine the predictors of CNSE nosocomial incidence rates according to their mechanism of resistance.

METHODS

A time-series analysis was conducted (July 2013 to December 2018) to evaluate the relationship in time between hospital antibiotic use and the percentage of adherence to hand hygiene with the CNSE rates.

FINDINGS

In all, 20,641 non-duplicated Enterobacterales isolates were identified; 2.2% were CNSE. Of these, 48.1% and 51.9% were CPE and NCP-CNSE, respectively. Of the CPE, 78.3% possessed a bla_OXA-232 gene. A transfer function model was identified for CNSE, CPE, and OXA-232 CPE that explained 20.8%, 19.3%, and 24.2% of their variation, respectively. According to the CNSE and CPE models, an increase in piperacillin-tazobactam (TZP) use of 1 defined daily dose (DDD) per 100 hospital patient-days (HPD) would lead to an increase of 0.69 and 0.49 CNSE and CPE cases per 10,000 HPD, respectively. The OXA-232 CPE model estimates that an increase of 1 DDD per 100 HPD of TZP use would lead to an increase of 0.43 OXA-232 CPE cases per 10,000 HPD. A transfer function model was not identified for NCP-CNSE, nor was there an association between the adherence to handhygiene and the CNSE rates.

CONCLUSION

The use of TZP is related in time with the CPE nosocomial rates, mostly explained by its effect on OXA-232 CPE.

High prevalence of MDR gram-negative bacteria in feces of healthy blood donors in Mexico

During the initial stage of a study to recruit universal intestinal microbiota donors in Mexico City, we found multiple "healthy" subjects that colonized with MDRO (Multidrug-resistant organisms). We aimed to describe clinical and demographic characteristics of these individuals. This was a prospective observational study. Participants were consecutively recruited among blood donors. A fecal sample was collected from each subject and analyzed at the same day in search of MDRO through chromographic culture media and, if growth observed, later confirmed by MALDI-TOF and susceptibility testing in Vitek 2 system. From July 2018 to March 2019, 85 individuals were screened for fecal colonization. Median age was 35 years (IQR 27-46 years), and 48/85 (56.4%) were males. Seventy-two (84.7%) subjects harbored at least one MDRO. ESBL-producing microorganisms were found in 72/85 (84.3%) subjects, and E. coli was the most frequent (63/85, 74.1%). Four samples (2 E. coli, 2 P. aeruginosa, 2.4% each) harbored carbapenem-resistant Enterobacteriaceae (CRE), together with an ESBL-producing microorganism. Antibiotic use (p = 0.06) and PPIs or H2-blockers intake (p = 0.03) were more common in the colonized subjects during the previous 6-month period. We report a high incidence of enteric colonization of healthy subjects with MDRO, a condition that may be related to antibiotics or PPIs/H2-blockers consumption. This surprisingly high MDRO colonization rate in potential FMT donors emphasizes the need for careful screening of donors to avoid possible transmission to FMT recipients.

1748. Incidence of Cytomegalovirus Disease and Viral Replication Kinetics in Intermediate Risk Liver Transplant Recipients Managed According to a Preemtive Therapy Algortihm

Background

Cytomegalovirus (CMV) is an important opportunistic pathogen in liver transplant recipients (LTR). Risk of invasive disease is determined by CMV donor/recipient (D/R) serostatus, immunosuppression, and use of antiviral prophylaxis. Viral replication kinetics that can predict the development of CMV disease in transplant recipients are a high maximal viral load (VL) and a fast replication velocity. At our institution LTR at intermediate risk for CMV disease (CMV D/R+) are managed following a preemptive therapy algorithm (the pre-established cutoff for treatment initiation is 4,000 IU/mL). The primary endpoint of this study was to determine the incidence of early CMV disease in CMV D/R+ LTR. Secondary endpoints were to calculate the period of maximal VL and viral kinetic parameters.

Methods

We performed a retrospective observational study of CMV D/R+ LTR. Patients were followed for 6 months after transplantation. We calculated the incidence of CMV disease. Viral kinetic parameters calculated were the VL duplication time (Td) and the basic reproductive number (R0). For the assessment of viral kinetics we used the maximal VL of 10 patients who had a VL determined within the previous week.

Results

Forty CMV D/R+ LTR were included. The median age was 52 years, 65% were women. The mean MELD score was 18, 83% of patients had decompensated cirrhosis. No patient developed CMV disease during the first 6 months after LT. Nineteen patients (47%) had CMV DNAemia, but only 8 (20%) required antiviral therapy. The highest VLs were observed during the second month after transplant. The median duplication time was 2.14 days. The median R0 was 1.46.

Conclusion

Although limited by our sample size, our algorithm appears useful for discriminating the patients who need antiviral treatment from those who will only have asymptomatic DNAemia. The study population VL, Td and R0 behave as described by other groups, which emphasizes the need for frequent monitoring. This is a challenge for CMV prevention in resource-limited countries.

Disclosures

All authors: No reported disclosures.

2375. Association Between Clostridium difficile Colonization and Inflammatory Bowel Disease Activity

Background

Clostridium difficile (CD) is a frequent cause of nosocomial infectious diarrhea. Despite no clear evidence has linked CD colonization (CDC) or CD infection (CDI) with inflammatory bowel disease activity (IBDA), data in our setting has suggested the contrary.

Methods

Prospective cohort study in a tertiary care hospital in Mexico City. Patients aged ≥18 years with IBD in clinical remission were included between April 2017 and April 2019. Demographic, clinical and laboratory variables, as well as three fecal samples, were collected at inclusion and during follow-up. CDC was defined as a positive GDH test without diarrhea. CDI was defined as diarrhea (as per IDSA criteria) plus positive GDH and PCR tests. IBDA was defined as bloody diarrhea plus a negative GDH test. The primary outcome was the association between CDC and IBDA. Secondary outcomes were incidence rates of CDC and CDI, including risk factors associated with CDC. Univariate and multivariable analyses were performed considering P < 0.05 as statistically significant.

Results

Out of 250 IBD patients, 101 cases met inclusion criteria and 85 completed follow-up (median = 420 days, IQR = 243–511 days). Twenty-three cases (27%) had IBDA during follow-up, eight cases had new CDC (incidence of 8.2/100 person-years), and one case developed CDI (incidence of 1.0/100 person-years). Figure 1 shows the cumulative percentage of cases without CDC during follow-up. In univariate analysis, the following were associated with CDC: decreasing age, decreasing age when IBD was diagnosed, residence in Mexico City or the State of Mexico, and hospitalization during follow-up. In Cox regression analysis, a decreasing age when IBD was diagnosed (HR = 0.92, CI95% = 0.87–0.98, p = 0.009) and residence in the State of Mexico (HR = 5.88, CI 95% = 1.21–28.60, p = 0.028) remained significantly associated with CDC. However, we did not find a statistically significant association between new CDC events and IBDA during a median follow-up period extending beyond 1 year.

Conclusion

We found no association between CDC and IBDA. Risk factors associated with CDC were residence in the State of Mexico and a decreasing age when IBD was diagnosed.

Disclosures

All authors: No reported disclosures.

Consensus on the prevention, diagnosis, and treatment of Clostridium difficile infection

In recent decades, Clostridium difficile infection (CDI) has become a worldwide health problem. Mexico is no exception, and therefore the Asociación Mexicana de Gastroenterología brought together a multidisciplinary group (gastroenterologists, endoscopists, internists, infectious disease specialists, and microbiologists) to carry out the "Consensus on the prevention, diagnosis, and treatment of Clostridium difficile infection", establishing useful recommendations (in relation to the adult population) for the medical community. Said recommendations are presented herein. Among them, it was recognized that CDI should be suspected in subjects with diarrhea that have a history of antibiotic and/or immunosuppressant use, but that it can also be a community-acquired infection. A 2-step diagnostic algorithm was proposed, in which a highly sensitive test, such as glutamate dehydrogenase (GDH), is first utilized, and if positive, confirmed by the detection of toxins through immunoassay or nucleic acid detection tests. Another recommendation was that CDI based on clinical evaluation be categorized as mild-moderate, severe, and complicated severe, given that such a classification enables better therapeutic decisions to be made. In mild-moderate CDI, oral vancomycin is the medication of choice, and metronidazole is recommended as an alternative treatment. In addition, fecal microbiota transplantation was recognized as an efficacious option in patients with recurrence or in the more severe cases of infection, and surgery should be reserved for patients with severe colitis (toxic megacolon), in whom all medical treatment has failed.

Azole resistance and cyp51A mutation screening in Aspergillus fumigatus in Mexico

Background

Fungicide exposure in the environment has driven the emergence of azole-resistant Aspergillus fumigatus worldwide. A screening test allows identification of resistant isolates.

Objectives

We screened clinical samples for azole-resistant Aspergillus through azole-containing agar plates and identified mutations in the cyp51A gene of A. fumigatus.

Methods

Aspergillus isolates from clinical samples collected in a tertiary care centre from 2014 to 2017 were screened for azole resistance. Samples were subcultured in azole-containing agar plates. Isolates with a positive screening test were subject to DNA extraction, DNA amplification and sequencing of the cyp51A gene (coding and promoter regions). Clinical data were obtained from medical records.

Results

We screened 43 Aspergillus isolates from 39 patients for azole resistance. Three isolates from three patients grew on azole-containing agar plates: two A. fumigatus and one Aspergillus flavus. PCR analysis and cyp51A sequencing identified the TR34/L98H mutation in both A. fumigatus isolates. The prevalence of cyp51A mutations among A. fumigatus was 8.3% (2/24). Both patients with TR34/L98H mutants were azole naive and presented with invasive aspergillosis; one had multiple myeloma and the other was a liver retransplant recipient. They suffered progressive disease and failed voriconazole therapy.

Conclusions

To the best of our knowledge, this is the first report of azole-resistant A. fumigatus with the TR34/L98H mutation in two azole-naive patients with refractory invasive aspergillosis in Mexico.

Drugs in Clinical Development for Fungal Infections

Despite increasing rates of invasive fungal infections being reported globally, only a single antifungal drug has been approved during the last decade. Resistance, toxicity, drug interactions and restricted routes of administration remain unresolved issues. This review focuses on new antifungal compounds which are currently in various clinical phases of development. We discuss two azoles with a tetrazole moiety that allows selective activity against the fungal CYP: VT-1161 for Candida infections and VT-1129 for cryptococcal meningoencephalitis. We also discuss two glucan synthesis inhibitors: CD101, an echinocandin with an increased half-life, and SCY-078 with oral bioavailability and increased activity against echinocandin-resistant isolates. Among the polyenes, we discuss MAT023, an encochleated amphotericin B formulation that allows oral administration. Two novel classes of antifungal drugs are also described: glycosylphosphatidylinositol inhibitors, and the leading drug APX001, which disrupt the integrity of the fungal wall; and the orotomides, inhibitors of pyrimidine synthesis with the leading drug F901318. Finally, a chitin synthesis inhibitor and progress on human monoclonal antifungal antibodies are discussed.

Mycobacterium tuberculosis complex bacteremia among HIV and non-HIV patients in a Mexican tertiary care center

Objectives

To determine the factors associated with Mycobacterium tuberculosis complex-positive blood culture.

Methods

Case-control study. Sociodemographic, clinical and laboratory data were collected from 2000 to 2015.

Results

We reviewed medical records of 533 patients with culture-proven tuberculosis, of whom 27.2% (145/533) had blood culture available. Patients with mycobacteremia presented more frequently with abdominal tuberculosis, body mass index <18 kg/m², and had lower hemoglobin and albumin levels. No differences were observed regarding HIV status.

Conclusions

Few studies have reported on the characteristics associated with Mycobacterium tuberculosis complex bacteremia, especially among Human Immunodeficiency Virus-negative patients. Out of 145 tuberculosis-infected patients with blood culture results available, 21 turned out positive. Anemia, hypoalbuminemia, and a body mass index < 18 kg/m² were associated with mycobacteremia.

Pneumonia in patients with systemic lupus erythematosus: Epidemiology, microbiology and outcomes

Background and objective Pneumonia remains the main cause of mortality in patients with systemic lupus erythematosus (SLE). The aim of the study was to establish the clinical characteristics, microbiology and risk factors for poor prognosis in patients with SLE and pneumonia. Methods We reviewed medical records of patients with SLE (American College of Rheumatology criteria) and pneumonia who attended the emergency room in a single tertiary care center (January 2010-March 2015). We collected demographics, treatment and disease activity (SLEDAI-2K) data. Severity scales of pneumonia (CURB-65 (acronym for risk factors measured: confusion, urea nitrogen, respiratory rate, blood pressure, 65 years of age and older) and Pneumonia Severity Index (PSI)) were obtained. A negative composite outcome was defined as need for mechanical ventilation, septic shock or death secondary to pneumonia up to 30 days after discharge. We conducted a univariate and multivariable analysis. Results We studied 158 patients (76% women) with 187 episodes of pneumonia. There were no differences in age, SLE duration, SLE activity, treatment or comorbidities between patients with negative composite outcome vs the other group. In 53 episodes, patients presented with a negative composite outcome. Of these, 46 (24.6%) required intubation, 13 (7%) developed shock and 12 (6.4%) died. The most common bacteria isolated was S. aureus, and we observed a high percentage of nonhabitual microorganisms. Fifteen percent of patients who presented with a negative outcome had low values on CURB-65 and PSI scales. Conclusion Patients with SLE and pneumonia have a high risk of complications and present with a high percentage of nonhabitual microorganisms. Severity scales for pneumonia can misclassify as low risk SLE patients with poor prognosis.

First case of Nocardia amamiensis pulmonary infection in Mexico

We report a case of Nocardia amamiensis pulmonary infection in a 43-year-old immunocompromised woman. The patient was treated with imipenem/cilastatin and trimethoprim/sulfamethoxazole and had a favourable outcome. It is important that laboratories perform species identification to understand the epidemiology and susceptibility patterns of the different Nocardia spp.

Human tuberculosis caused by Mycobacterium bovis: a retrospective comparison with Mycobacterium tuberculosis in a Mexican tertiary care centre, 2000-2015

Background

Human tuberculosis caused by Mycobacterium bovis is believed to be frequent in developing countries. Transmission is usually through ingestion of unpasteurized dairy products, although airborne contagion is possible. Disease caused by M. tuberculosis or M. bovis is clinically indistinguishable from each other. The aim of this study was to determine the factors associated with M. bovis disease.

Methods

Retrospective analysis of all culture-positive cases of M. bovis and M. tuberculosis from 2000 to 2015, in a Mexican tertiary-care centre. Sociodemographic, clinical, and radiographic data from medical records were compared. Disease site was classified as pulmonary, extrapulmonary, or pulmonary and extrapulmonary, based on cultures.

Results

We evaluated 533 cases, 372 (69.7 %) of which were caused by M. tuberculosis and 161 (30.2 %) by M. bovis. Characteristics associated with M. bovis disease were: younger age (aOR 0.97, 95 % CI 0.95–0.98), glucocorticoid use (aOR 2.27, 95 % CI 1.42–3.63), and extrapulmonary disease (aOR 1.80, 95 % CI 1.21–2.69). M. tuberculosis was associated with lower socioeconomic status (aOR 0.52, 95 % CI 0.28–0.97). When we analysed only pulmonary cases, younger age (aOR 0.97, 95 % CI 0.96–0.99), glucocorticoid use (aOR 2.41, 95 % CI 1.30–4.46), and smoking (aOR 1.94, CI 95 % 1.15–3.27) were associated with M. bovis. Both groups showed similar proportions of direct microscopy smear results (respiratory samples) and chest X-ray cavitations.

Conclusions

Younger age, glucocorticoid use, and extrapulmonary disease were associated with M. bovis as the causative agent of tuberculosis in a group of patients from a tertiary care centre in a country where bovine tuberculosis is endemic. Further studies must be conducted in the general population to determine pathogen-specific associated factors and outcomes.

Factors Associated to Prevalence and Incidence of Carbapenem-Resistant Enterobacteriaceae Fecal Carriage: A Cohort Study in a Mexican Tertiary Care Hospital

Background

Carbapenem-resistant Enterobacteriaceae (CRE) infections have emerged as a serious threat to health worldwide. They are associated with increased morbidity and mortality and are capable of silently colonizing the gastrointestinal tract. Because of this, there is great interest to characterize the epidemiology of CRE carriage and acquisition in healthcare facilities. The aim of this study was to determine the prevalence and factors associated with CRE fecal carriage (CRE-fc), and risk factors for incident cases.

Methods/Results

A cohort study was conducted at a tertiary care hospital from January 1^st to April 30^th, 2014 during a CRE outbreak. Weekly rectal swabs were performed in patients considered at risk until discharge. CRE-fc prevalence was 10.9% (CI 95% 7.7–14.7) among 330 patients. Treatment with carbapenems (OR 2.54, CI 95% 1.15–5.62); transfer from an institution (OR 2.16, CI 95% 1.02–4.59); multi-drug resistant infection within the previous six months (OR 2.81, CI 95% 1.47–5.36); intensive care unit admission (OR 0.42, CI 95% 0.20–0.88); hematologic malignancy (OR 4.02, CI 95% 1.88–8.06); invasive procedures (OR 2.18, CI 95% 1.10–4.32); and sharing a room with a known CRE carrier (OR 3.0, CI 95% 1.43–6.31) were independently associated factors for CRE-fc. Risk factors associated with CRE-fc incidence were determined for 87 patients initially negative and with subsequent screening; the incidence rate was 2.5 cases, per 1000 person-years (CI 95% 1.5–3.9). Independently associated risk factors were carbapenem treatment (HR 2.68, CI 95% 1.03–6.98), hematologic malignancy (HR 5.74, 95% CI 2.46–13.4) and a mean daily colonization pressure ≥10% (HR 5.03, IC 95% 1.77–14.28). OXA-48-like (OXA-232) and CTX-M-15 were the predominantly identified mechanisms of resistance.

Conclusions

We found an elevated incidence and prevalence of CRE-fc in our hospital. Hematologic patients need to be considered a population at risk, and antibiotic stewardship along with infection control programs need to be improved to avoid nosocomial spread.

Impact of ertapenem on antimicrobial resistance in a sentinel group of Gram-negative bacilli: a 6 year antimicrobial resistance surveillance study

OBJECTIVES

To determine the association between ertapenem and resistance of Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae and Acinetobacter baumannii-calcoaceticus complex to different antimicrobials while adjusting for relevant hospital factors.

METHODS

This was a retrospective time-series study conducted at a tertiary care centre from September 2002 to August 2008. The specific impact of ertapenem on the resistance of these Gram-negative bacilli (GNB) was assessed by multiple linear regression analysis, adjusting for the average length of stay, rate of hospital-acquired infections and use of 10 other antimicrobials, including type 2 carbapenems.

RESULTS

Unadjusted analyses revealed significant increases over the duration of the study in the number of GNB resistant to meropenem/imipenem among 1000 isolates each of E. coli (0.46 ± 0.22, P < 0.05), P. aeruginosa (6.26 ± 2.26, P < 0.05), K. pneumoniae (8.06 ± 1.50, P < 0.0005) and A. baumannii-calcoaceticus complex (25.39 ± 6.81, P < 0.0005). Increased resistance to cefepime (and other extended-spectrum cephalosporins) was observed in E. coli (9.55 ± 1.45, P < 0.0005) and K. pneumoniae (15.21 ± 2.42, P < 0.0005). A. baumannii-calcoaceticus complex showed increased resistance to all antimicrobials except amikacin. After controlling for confounders, ertapenem was not significantly associated (P > 0.05) with changes in resistance for any pathogen/antimicrobial combination.

CONCLUSIONS

After controlling for confounders, ertapenem was not associated with changes in resistance in a group of sentinel GNB, although significant variations in resistance to different antimicrobials were observed in the unadjusted analyses. These results emphasize the importance of implementation of local resistance surveillance platforms and stewardship programmes to combat the global emergence and spread of antimicrobial resistance.

Effect of isoniazid on antigen-specific interferon-γ secretion in latent tuberculosis

Treatment of persons with latent tuberculosis (TB) infection at greatest risk of reactivation is an important component of TB control and elimination strategies. Biomarkers evaluating the effectiveness of treatment of latent TB infection have not yet been identified. This information would enhance control efforts and assist the evaluation of new treatment regimes.

We designed a two-group, two-arm, randomised clinical study of tuberculin skin test-positive participants: 26 with documented contact with TB patients and 34 with non-documented contact. Participants in each group were randomly assigned to the immediate- or deferred-isoniazid treatment arms. Assays of in vitro interferon (IFN)-γ secretion in response to recombinant Rv1737 and overlapping synthetic peptide pools from various groups of immunodominant proteins were performed.

During isoniazid therapy, a significant increase from baseline in the proportion of IFN-γ responders to the 10-kDa culture filtrate protein, Rv2031, Rv0849, Rv1986, Rv2659c, Rv2693c and the recombinant Rv1737 protein was observed (p⩽0.05). The peptide pool of Rv0849 and Rv1737 recombinant proteins induced the highest percentage of IFN-γ responders after isoniazid therapy.

The in vitro IFN-γ responses to these proteins might represent useful markers to evaluate changes associated with treatment of latent TB infection.

Peptide pool of Rv0849 and recombinant protein Rv1737 may be useful to test the efficacy of treatment of latentTBhttp://ow.ly/Catld

Epidemiology of Invasive Fungal Infections in Latin America

The pathogenic role of invasive fungal infections (IFIs) has increased during the past two decades in Latin America and worldwide, and the number of patients at risk has risen dramatically. Working habits and leisure activities have also been a focus of attention by public health officials, as endemic mycoses have provoked a number of outbreaks. An extensive search of medical literature from Latin America suggests that the incidence of IFIs from both endemic and opportunistic fungi has increased. The increase in endemic mycoses is probably related to population changes (migration, tourism, and increased population growth), whereas the increase in opportunistic mycoses may be associated with the greater number of people at risk. In both cases, the early and appropriate use of diagnostic procedures has improved diagnosis and outcome.

Increasing prevalence of extended-spectrum-beta-lactamase among Gram-negative bacilli in Latin America--2008 update from the Study for Monitoring Antimicrobial Resistance Trends (SMART)

OBJECTIVES

This analysis of the Study for Monitoring Antimicrobial Resistance Trends (SMART) evaluated the susceptibility patterns of Enterobacteriaceae in Latin America in 2008, with emphasis on susceptibility trends of E. coli and K. pneumoniae.

METHODS

Clinical isolates were recovered from intra-abdominal infections (IAI) from 23 centers in 10 Latin American countries. Isolates were sent to a central laboratory for confirmation of identification, antimicrobial susceptibility and ESBL testing, following the Clinical Laboratory Standards Institute (CLSI) guidelines.

RESULTS

Of 1,003 Gram-negative bacilli collected from intra-abdominal infections, E. coli and K. pneumoniae were the most commonly isolated organisms, and 26.8% of E. coli and 37.7% of K. pneumoniae were ESBL positive. Ertapenem and imipenem were the most consistently active agents tested; 99% of ESBL-positive E. coli isolates were susceptible to ertapenem and 100% to imipenem as well, and 91% of ESBL-positive K. pneumoniae were susceptible to ertapenem and 98% to imipenem. Quinolones and cephalosporins were less active, achieving 1.5% to 76% inhibition against ESBL-producing E. coli and 3.5% to 61% inhibition against K. pneumoniae.

CONCLUSIONS

Local and unit-specific surveillance data is particularly important for selection of empiric therapy and in community-acquired infections as they can help the clinician with antibiotic selection by providing guidance regarding the likely pathogens and their resistance profiles. Our data also confirm the increasing frequency with which ESBL-producing organisms are found in the community setting, with 31.4% of community-acquired and 24.9% of hospital-acquired infections found to produce ESBLs. Imipenem and ertapenem are the most active agents tested for ESBL-positive E. coli and K. pneumoniae.

Salvaging diabetic foot through debridement, pressure alleviation, metabolic control, and antibiotics

There is a fatalist perception of diabetic foot because the argument of "small-vessel disease" prevails. This is the report of a cohort study of patients facing a formal recommendation for major foot amputation to assess how many can be saved with a conventional treatment, defined as debridement, pressure alleviation, metabolic control, and antibiotics. The primary efficacy measurement was the salvage of the limb at the follow-up visit between 25 and 35 days after the first consultation. The secondary efficacy measurement was the subsequent epithelization of the ulcerative lesions, following patients for up to 270 days. The cohort consisted of 105 type 2 diabetic patients; 87 (83%) had severe lesions. A total of 71 patients (68%) required hospitalization. By the intention-to-treat analysis, 89 patients (85%) avoided major amputation. A total of 88 patients were evaluated for complete epithelization, reaching median success by day 120. Overall, 51 patients (49%) underwent minor amputations. It was concluded that there is a high rate of unnecessary major foot amputations, because a diabetic foot can be salvaged across the continuum of severity when patients receive care in a multidisciplinary wound clinic.

Tracing the source of an outbreak of methicillin-resistant Staphylococcus aureus in a tertiary-care oncology hospital by epidemiology and molecular methods

This study describes the clinical and molecular characteristics of methicillin-resistant Staphylococcus aureus (MRSA) isolates that emerged after an index case in a tertiary-care oncology hospital in Mexico City and identifies whether these isolates were related with the index case. All MRSA strains isolated from January 2006 until December 2007 were included. The clinical and demographic characteristics of patients were analyzed; molecular typing by pulsed-field gel electrophoresis was used to characterize the isolates. We included 44 MRSA isolates from 55 patients. Thirty-eight patients (86.4%) were classified with nosocomial infection and the remainder with healthcare-related infection. A single pulsed-field gel electrophoresis pattern (C) was identified with minor variations (two subtypes). The isolates analyzed were staphylococcal chromosome cassette mec type II (related with the New York-Japan strain). This case underscores the need to intensify strategies that identify and limit the spread of multiresistant pathogens imported by infected patients referred from other healthcare centers.

Contamination of intravenous fluids: a continuing cause of hospital bacteremia

BACKGROUND

Nosocomial bacteremia caused by the contamination of intravenous (IV) infusates is considered rare. Unfortunately, this problem has been underestimated because its identification requires culturing infusates, a procedure not performed routinely.

METHODS

This study was conducted in a referral hospital where IV infusates are admixed in nursing areas. The aim was to determine the prevalence of infusate contamination in adult patients with gram-negative rod (GNR) bacteremia. Over a period of 32 months, a specimen of infusate was drawn for culture from each patient recruited after the laboratory reported a GNR in the blood.

RESULTS

A total of 384 infusates were cultured from 384 patients who had been diagnosed with GNR bacteremia. Seven infusates grew a GNR in culture, for a contamination rate of 2% (7/384; 95% confidence interval [CI] = 1% to 3%). In all cases, the infectious organism was the same as the organism isolated from the blood. Infusate contamination was responsible for 7% (7/108; 95% CI = 2% to 11%) of all primary bloodstream infections and 11% (7/62; 95% CI = 2% to 22%) of all primary bloodstream infections not associated with central venous catheter infection.

CONCLUSIONS

For patients in hospitals where IV drugs are admixed in nursing units, we recommend instituting infusate culture as routine practice following the diagnosis of a GNR in the blood.

Virulence, immunopathology and transmissibility of selected strains of Mycobacterium tuberculosis in a murine model

After encounter with Mycobacterium tuberculosis, a series of non-uniform immune responses are triggered that define the course of the infection. Eight M. tuberculosis strains were selected from a prospective population-based study of pulmonary tuberculosis patients (1995-2003) based on relevant clinical/epidemiological patterns and tested in a well-characterized BALB/c mouse model of progressive pulmonary tuberculosis. In addition, a new mouse model of transmissibility consisting of prolonged cohousing (up to 60 days) of infected and naïve animals was tested. Four phenotypes were defined based on strain virulence (mouse survival, lung bacillary load and tissue damage), immunology response (cytokine expression determined by real-time polymerase chain reaction) and transmissibility (lung bacillary loads and cutaneous delayed-type hypersensitivity in naïve animals).We identified four clearly defined strain phenotypes: (1) hypervirulent strain with non-protective immune response and highly transmissible; (2) virulent strain, associated with high expression of proinflammatory cytokines (tumour necrosis factor and interferon) and very low anti-inflammatory cytokine expression (interleukins 4 and 10), which induced accelerated death by immunopathology; (3) strain inducing efficient protective immunity with lower virulence, and (4) strain demonstrating strong and early macrophage activation (innate immunity) with delayed participation of acquired immunity (interferon expression). We were able to correlate virulent and transmissible phenotypes in the mouse model and markers of community transmission such as tuberculin reactivity among contacts, rapid progression to disease and cluster status. However, we were not able to find correlation with the other two phenotypes. Our new transmission model supported the hypothesis that among these strains increased virulence was linked to increased transmission.

High prevalence of infections in patients with systemic lupus erythematosus and pulmonary haemorrhage

The main objective of this study is to describe the presence of infections in patients with pulmonary haemorrhage and systemic lupus erythematosus. Patients with systemic lupus erythematosus and pulmonary haemorrhage were thoroughly evaluated in the first 48 hours with imaging plus bronchoscopy and bronchoalveolar fluid analysis. If needed, videoassisted thoracoscopy and lung biopsy were performed too. In all, search for bacterial, mycobacterial and fungal infections proceeded. Appropriate blood, bronchoalveolar fluid and tissue cultures were taken. Patients were treated with antibiotics and corticosteroids in case of infection. Otherwise, they received initial intravenous methylprednsiolone pulses for 3 days as standard therapy for pulmonary haemorrhage in systemic lupus erythematosus. Additional treatment with immunosuppressives was further decided by the treating physicians. Fourteen events in 13 patients were evaluated. In eight events (57%), an infection was demonstrated. Aetiological agents included Pseudomonas sp. and Aspergillus fumigatus. Four patients died, three of them because of the pulmonary infection and one because of cerebral haemorrhage secondary to severe systemic hypertension, 48 hours after methylprednisolone treatment. Patients with systemic lupus erythematosus and pulmonary haemorrhage have a high prevalence of infections. The influence of pulmonary haemorrhage in the setting of systemic lupus erythematosus needs further study to establish adequate treatment and to reduce the high mortality of this complication.

A novel identification scheme for genus Mycobacterium, M. tuberculosis complex, and seven mycobacteria species of human clinical impact

Recently, the incidence of human mycobacterial infections due to species other than M. tuberculosis has increased worldwide. Since disease control depends on appropriate antimicrobial therapy, the precise identification of these species of clinical importance has become a major public health concern. Identification of mycobacteria has been hampered because of the lack of specific, rapid, and inexpensive methods. Therefore, we aimed at designing and validating a bacterial lysate-based polymerase chain reaction identification scheme. This scheme can classify clinical isolates into: (1) the genus Mycobacterium, (2) the M. tuberculosis complex, (3) the nontuberculous mycobacteria, and (4) the species M. avium, M. intracellulare, M. abscessus, M. chelonae, M. fortuitum and M. bovis of clinical importance, and M. gordonae, the most commonly encountered nonpathogenic species in clinical laboratories. By using M. fortuitum and M. avium lysates as models, the method sensitivity was determined to be 372 pg of DNA. In a blind parallel comparison between our approach and conventional biochemical tests, both assays correctly categorized 75 patient's mycobacterial isolates. However, our approach only required 4-9 h for categorization compared with at least 15 days by conventional tests. Furthermore, our methodology could also detect M. fortuitum and M. avium from liquid cultures, after only 2 and 6 days, respectively, of incubation. Our new identification scheme is therefore sensitive, specific, rapid, and economic. Additionally, it can help to provide proper treatment to patients, to control these diseases, and to improve our knowledge of the epidemiology of mycobacteriosis, all urgently needed, particularly in developing countries.

Gender differentials of pulmonary tuberculosis transmission and reactivation in an endemic area

BACKGROUND

In most low income countries there are twice as many cases of tuberculosis (TB) reported among men than among women, a difference commonly attributed to biological and epidemiological characteristics as well as socioeconomic and cultural barriers in access to health care. The World Health Organization has encouraged gender specific comparisons in TB rates to determine whether women with TB are less likely than men with TB to be diagnosed, reported, and treated. A study was undertaken to identify gender based differences in patients with pulmonary TB and to use this information to improve TB control efforts.

METHODS

Individuals with a cough for more than 2 weeks in southern Mexico were screened from March 1995 to April 2003. Clinical and mycobacteriological information (isolation, identification, drug susceptibility testing and IS6110 based genotyping, and spoligotyping) was collected from those with bacteriologically confirmed pulmonary TB. Patients were treated in accordance with official norms and followed to ascertain treatment outcome, retreatment, and vital status.

RESULTS

623 patients with pulmonary TB were enrolled. The male:female incidence rate ratio for overall, reactivated, and recently transmitted disease was 1.58 (95% CI 1.34 to 1.86), 1.64 (95% CI 1.36 to 1.98), and 1.41 (95% CI 1.01 to 1.96), respectively. Men were more likely than women to default from treatment (adjusted OR 3.30, 95% CI 1.46 to 7.43), to be retreated (hazard ratio (HR) 3.15, 95% CI 1.38 to 7.22), and to die from TB (HR 2.23, 95% CI 1.25 to 3.99).

CONCLUSIONS

Higher rates of transmitted and reactivated disease and poorer treatment outcomes among men are indicators of gender differentials in the diagnosis and treatment of pulmonary TB, and suggest specific strategies in endemic settings.

Changes in the geographical distribution of tuberculosis patients in Veracruz, Mexico, after reinforcement of a tuberculosis control programme

OBJECTIVE

Geographical information systems are valuable tools for studying tuberculosis (TB) epidemiology, but have been underused for the evaluation of TB control programs. We aimed to compare the geographical distribution of TB before and after the five elements of directly observed therapy, short course (DOTS) were strengthened in a Health Jurisdiction in Mexico in response to recommendations made by the WHO Global Tuberculosis Program.

METHODS

All consenting persons detected by passive case finding between March 1995 and February 2000 who were confirmed to have acid-fast bacilli (AFB) in sputum underwent clinical and laboratory evaluation. A TB 'episode' was defined as the period of time between bacteriological diagnosis and treatment discharge by the local control programme. Distances of TB episodes from the nearest urban centre were determined according to recent transmission and multidrug resistance (MDR).

RESULTS

During the first half of the study period, MDR episodes were located a median distance of 1.24 km from urban centres, which did not differ significantly from non-MDR episodes (1.14 km, P=0.56). In contrast, the median distance of MDR episodes increased 55% to 1.92 km during the second half, which placed them significantly further away out than non-MDR episodes (1.08 km, P=0.01). No changes in location were detected for recent transmission.

CONCLUSION

While reinforcing the TB control programme reduced the incidence of MDR, the remaining episodes were located in poorer and more remote areas.

Tuberculosis and diabetes in southern Mexico

OBJECTIVE

To determine the impact of diabetes on the rates of tuberculosis in a region where both diseases are prevalent.

RESEARCH DESIGN AND METHODS

Data from a population-based cohort of patients with pulmonary tuberculosis undergoing clinical and mycobacteriologic evaluation (isolation, identification, drug-susceptibility testing, and IS6110-based genotyping and spoligotyping) were linked to the 2000 National Health Survey (ENSA2000), a national probabilistic, polystage, stratified, cluster household survey of the civilian, noninstitutionalized population of Mexico.

RESULTS

From March 1995 to March 2003, 581 patients with Mycobacterium tuberculosis culture and fingerprint were diagnosed, 29.6% of whom had been diagnosed previously with diabetes by a physician. According to the ENSA2000, the estimated prevalence of diabetes in the study area was 5.3% (95% CI 4.1-6.5). The estimated rates of tuberculosis for the study area were greater for patients with diabetes than for nondiabetic individuals (209.5 vs. 30.7 per 100000 person-years, P < 0.0001).

CONCLUSIONS

In this setting, the rate of tuberculosis was increased 6.8-fold (95% CI 5.7-8.2, P < 0.0001) in patients with diabetes due to increases in both reactivated and recently transmitted infection. Comorbidity with diabetes may increase tuberculosis rates as much as coinfection with human immunodeficiency virus (HIV), with important implications for the allocation of health care resources.

Rapid identification and susceptibility testing of Mycobacterium tuberculosis from MGIT cultures with luciferase reporter mycobacteriophages

In a prospective study conducted in a diagnostic laboratory in Mexico City, luciferase reporter mycobacteriophages (LRPs) were evaluated for their utility and performance in identification and antibiotic-susceptibility testing of Mycobacterium tuberculosis complex (MTC) isolates from MGIT-960 cultures. Eighty-four consecutive MGIT cultures recovered from 54 patients were included in this study. The LRPs confirmed mycobacterial growth in 79 (94 %) of 84 MGIT cultures. Failure to confirm growth was due to low inoculum (n = 1) or growth with non-tuberculous mycobacteria (n = 4). The median time to confirmation of MGIT cultures was 1 day (range 1-55). Confirmed cultures were identified with p-nitro-alpha-acetylamino-beta-hydroxypropiophenone (NAP), a selective inhibitor of MTC species, and results obtained with LRPs were compared with those obtained by BACTEC-460. The sensitivity and specificity of the LRP NAP test were respectively 97 and 100 %, and the median turnaround time for identification was 3 days with both methods. The accuracy and speed of the LRPs for susceptibility testing with rifampicin, streptomycin, isoniazid and ethambutol were compared with BACTEC-460 and discrepant results were tested by the conventional agar proportion method. In total, 72 MTC cultures were tested. The overall agreement between the LRPs and BACTEC-460 was 98.6 %. Four isolates (5.6 %) were falsely identified as ethambutol-resistant. The median turnaround time for susceptibility testing was 3 days (range 3-57) with the LRPs and 9 days (range 7-29) with BACTEC-460. LRPs offer an accurate and rapid approach for identification and susceptibility testing of M. tuberculosis from MGIT-960 cultures.

Antibacterial resistance of community-acquired respiratory tract pathogens recovered from patients in Latin America: results from the PROTEKT surveillance study (1999-2000)

PROTEKT (Prospective Resistant Organism Tracking and Epidemiology for the Ketolide Telithromycin) is a global surveillance study established in 1999 to monitor antibacterial resistance of respiratory tract organisms. Thirteen centers from Argentina, Brazil and Mexico participated during 1999-2000; they collected 1806 isolates (Streptococcus pneumoniae 518, Haemophilus influenzae 520, Moraxella catarrhalis 140, Staphylococcus aureus 351, S. pyogenes 277). Overall, 218 (42.1%) of the S. pneumoniae isolates had reduced susceptibility to penicillin, 79 (15.3%) were penicillin-resistant and 79 (15.3%) were erythromycin-resistant. Mexico had the highest prevalence of penicillin (76.5%) and erythromycin (31.2%) resistance. Of 77 erythromycin-resistant S. pneumoniae tested for resistance genotype, 43 possessed mef(A), 33 possessed erm(B) and 1 possessed both erm(B) and mef(A) mechanism. All S. pneumoniae isolates were fully susceptible to telithromycin, linezolid, teicoplanin and vancomycin. Among H. influenzae isolates, 88 (16.9%) produced beta-lactamase, ranging from 11% (Brazil) to 24.5% (Mexico). Among M. catarrhalis isolates, 138 (98.6%) produced beta-lactamase. Twenty-four (8.7%) of the S. pyogenes isolates were erythromycin-resistant; resistance being attributable to mefA (n=18), ermTR (n=5) and ermB (n=1). All H. influenzae, M. catarrhalis and S. pyogenes were fully susceptible to telithromycin. Methicillin resistance was found in 26.5% of the S. aureus isolates (Argentina 15%; Mexico 20%; Brazil 31.3%). Telithromycin was effective against 97.7% of methicillin-susceptible isolates. PROTEKT confirms that antibacterial resistance is an emerging problem in Latin America. The previously reported high levels of pneumococcal resistance to the beta-lactam and macrolides were exceeded. New agents that do not induce resistance or that exert low selective pressure, e.g. telithromycin, are essential to safeguard future antibacterial efficacy.

Purified protein derivative reaction in systemic lupus erythematosus patients. Indirect study of cellular immunity

Cutaneous anergy in SLE patients results from disease activity and/or immunosuppressive treatment (IT). The aim of this study was to evaluate purified protein derivative (PPD) reaction in SLE patients. A total of 145 patients and 20 controls were studied. Five units of PPD were applied on day 0, and skin reaction was measured after 3 (PPD1) and 6 (PPD2) days. A booster was applied (day 14), and the reaction was measured after 3 (PPD3) and 6 (PPD4) days. Non-parametric ANOVA test and unpaired Student's t-test were performed. Forty patients (group I) were inactive (MexSLEDAI < 3), receiving no IT (at least 3 months previous to the PPD test); 39 (group II) were inactive receiving IT; 24 (group III) were active without IT, and 42 (group IV) were active with IT. Active patients had lower PPD1 (group III, 1.4 +/- 0.9; group IV, 0.6 +/- 0.5) than inactive patients (group I, 8.4 +/- 2.3; group II, 5.1 +/- 1.9) and than controls (9.4 +/- 3; P < or = 0.001). Group IV had lower delayed response (PPD2 = 0.3 +/- 0.3) than inactive groups (group I, 2.6 +/- 0.9; group II, 3.1 +/- 0.8) and than controls (7.9 +/- 2.5; P < or = 0.001). Group III had lower delayed reaction (PPD2 = 1.2 +/- 0.8) than controls (P < or = 0.001). Active SLE patients, receiving or not receiving IT, had lower skin response to PPD than inactive patients and controls.

Luciferase reporter mycobacteriophages for detection, identification, and antibiotic susceptibility testing of Mycobacterium tuberculosis in Mexico

The utility of luciferase reporter mycobacteriophages (LRPs) for detection, identification, and antibiotic susceptibility testing of Mycobacterium tuberculosis was prospectively evaluated in a clinical microbiology laboratory in Mexico City, Mexico. Five hundred twenty-three consecutive sputum samples submitted to the laboratory during a 5-month period were included in this study. These specimens were cultivated in Middlebrook 7H9 (MADC), MGIT, and Löwenstein-Jensen (LJ) media. Of the 71 mycobacterial isolates recovered with any of the three media, 76% were detected with the LRPs, 97% were detected with the MGIT 960 method, and 90% were detected with LJ medium. When contaminated specimens were excluded from the analysis, the LRPs detected 92% (54 of 59) of the cultures. The median time to detection of bacteria was 7 days with both the LRPs and the MGIT 960 method. LRP detection of growth in the presence of p-nitro-alpha-acetylamino-beta-hydroxypropiophenone (NAP) was used for selective identification of M. tuberculosis complex (MTC) and compared to identification with BACTEC 460. Using the LRP NAP test, 47 (94%) out of 50 isolates were correctly identified as tuberculosis complex. The accuracy and speed of LRP antibiotic susceptibility testing with rifampin, streptomycin, isoniazid, and ethambutol were compared to those of the BACTEC 460 method, and discrepant results were checked by the conventional proportion method. In total, 50 MTC isolates were tested. The overall agreement between the LRP and BACTEC 460 results was 98.5%. The median LRP-based susceptibility turnaround time was 2 days (range, 2 to 4 days) compared to 10.5 days (range, 7 to 16 days) by the BACTEC 460 method. Phage resistance was not detected in any of the 243 MTC isolates tested. Mycobacteriophage-based approaches to tuberculosis diagnostics can be implemented in clinical laboratories with sensitivity, specificity, and rapidity that compare favorably with those of the MGIT 960 and BACTEC 460 methods. The phages currently provide the fastest phenotypic assay for susceptibility testing.

[Drug resistance of Mycobacterium tuberculosis in Orizaba, Veracruz. Implications for the tuberculosis prevention and control program]

BACKGROUND

Tuberculosis, declared a global emergency by the World Health Organization, continues to be an important public health problem in Mexico, included in the first twenty causes of death.

OBJECTIVE

To know the impact of drug resistance of Mycobacterium tuberculosis on treatment outcome, need of re-treatment and mortality in a cohort of patients with pulmonary tuberculosis receiving directly observed therapy, short course (DOTS).

METHODS

We conducted a population-based study in a suburban region in Southern Mexico. People who had been coughing for more than two weeks underwent sputum acid-fast bacilli smear. Patients with a positive smear were recruited and underwent clinical exam, chest X-ray, HIV testing, and sputum cultures. Identification, drug susceptibility testing and restriction fragment length polymorphism analysis (RFLP) were performed in all isolates. Patients were followed every 12 months for new episodes of tuberculosis and vital status. Patients were referred for clinical care to the local program of tuberculosis. Deaths were corroborated with death certificates. Informed consent was obtained from participants.

RESULTS

Between March 1995 and February 1999, tuberculosis was diagnosed in 371 patients who were followed for an average of 32 months. M. tuberculosis was cultured from 316 patients; resistance to any drug occurred in 25.0% of isolates (primary 18.8%, acquired 49.2%); only to isoniazid in 6.8% (primary 7.3%, acquired 4.8%); to isoniazid and rifampin in 6.2% (primary 1.6%, acquired 23.8%). Patients with drug resistance had a higher probability of treatment failure (OR = 16.9, CI 95% 4.5-63.0) and patients with MDR strains had a higher probability of need of re-treatment (RR = 24.4, CI 95% 8.8-67.6), and of death (RR = 4.0, CI 95% 1.5-10.7). Additional variables were found to be associated with subsequent episodes of disease and mortality: Cocaine use, chronic disease, type of radiological lesions, HIV co-infection, non-compliance and treatment delay, as well as RFLP clustering.

CONCLUSIONS

In this study, we observed that drug resistance showed a severe impact on the outcome and survival; drug-resistance was the most significant factor for these negative outcomes; DOTS may not be sufficient in areas where drug resistance is considerable, and patient follow-up for longer periods of time, as compared to evaluation at the end of treatment, provides additional information which is useful for prevention and control programs.

[Trends for bacteremia and risk factors for death in a tertiary hospital in Mexico City. 1981-1992]

OBJECTIVE

To describe the trends and risk factors of death for bacteremia in adult from a tertiary-care center from 1981 to 1992.

MATERIAL AND METHODS

We randomly included 20% of bacteremic episodes per year.

RESULTS

47,618 blood-cultures from 19,530 patients, 3428 patients (17.6%) had bacteremia (285/y). From 600 episodes (50/y), 307 were from men, 368 were hospital-acquired (HA), and 88% were monomicrobial. Diabetes mellitus was seen in 103 cases, cirrhosis of the liver in 98, and AIDS in 33, among others. The main microorganisms were: Escherichia coli (177), Klebsiella pneumoniae (53), Enterobacter (50), Salmonella (45) and Pseudomonas aeruginosa (35); coagulase-negative staphylococci (CNS) (116), Staphylococcus aureus (56), and enterococci (22), and Candida (20). CNS decreased during the study (p < 0.01), but Candida spp., Stenotrophomonas maltophilia and enterococci increased (p < 0.01). The crude mortality of the HA bacteremia was 70.8%, and 29.2% in the case of community-acquired, the mortality attributable to HA bacteremia was 41.6%. The main risk factors were: cardiac valvular disease (p < 0.001), stay at the intensive-care unit (p < 0.001), sepsis (p < 0.001), and pneumonia (p < 0.001).

DISCUSSION

Bacteremia had a significant impact on mortality during the study period that has not change despite opportune therapy, Enterococci and candida have emerged as significant pathogens.

rpoB Gene mutations in rifampin-resistant Mycobacterium tuberculosis identified by polymerase chain reaction single-stranded conformational polymorphism

The use of polymerase chain reaction-single-stranded conformational polymorphism (PCR-SSCP) to study rpoB gene mutations in rifampin-resistant (RIFr) Mycobacterium tuberculosis has yielded contradictory results. To determine the sensitivity of this method, we analyzed 35 RIFr strains and 11 rifampin-susceptible (RIFs) strains, using the DNA sequencing of the core region of rpoB for comparison. Of the RIFr, 24 had a PCR-SSCP pattern identical to that of H37Rv; the other 11 had four different patterns. The 11 RIFs had PCR-SSCP patterns identical to that of H37Rv. The sensitivity of the assay was 31.4%; its specificity was 100%. We observed a strong correlation between the degree of resistance and the type of mutation.

Mycobacterium tuberculosis drug resistance in a suburban community in southern Mexico

OBJECTIVE

To determine the impact of drug resistance (DR) on the clinical outcome and transmission of tuberculosis under programmatic conditions.

METHODS

Prospective cohort and molecular epidemiologic study in the Orizaba Health Jurisdiction of Mexico. Between March 1995 and July 1999, chronic coughers with positive acid-fast bacilli (AFB) detected in sputum smear underwent clinical and mycobacteriologic evaluation (species identification, drug susceptibility testing and IS6110-based genotyping). Treatment was provided in accordance with official norms.

RESULTS

Mycobacterium tuberculosis was isolated from 326/387 AFB-positive cases. The rate of DR was 24.2% and that of multidrug resistance (MDR, defined as resistance to both isoniazid and rifampin at least) was 7.7%; 78% were cured, 8% abandoned treatment, 6% failed treatment, and 5% died. An additional 13.5% received retreatment and 8.9% died during a median 28.6 months of follow up. Factors associated with DR by multivariate analysis were chronicity of tuberculosis (OR 4.8, 95%CI 2.7-8.4, P < 0.001), age >40 years (OR 1.9, 95%CI 1.1-3.2, P = 0.02) and indigenous origin (OR 0.3, 95%CI 0.13-0.75, P = 0.01). Cox-adjusted relative risks showed that MDR (RR 2.5, 95%CI 1.02-6.16, P = 0.04), HIV infection (RR 31.3, 95%CI 11.6-84.8, P < 0.001), and chronicity of tuberculosis (RR 2.1, 95%CI 1.0-4.4, P = 0.06) were associated with mortality, controlling for age. Predictors of retreatment were DR (not including MDR) (RR 2.2 95%CI 0.89-5.31, P < 0.087), MDR (RR 12.6, 95%CI 5.46-28.88, P < 0.001), and living in a household with an earthen floor (RR 2.8, 95%CI 1.27-6.13, P = 0.011). Being infected with MDR-TB was the only factor associated with a decreased likelihood of being in an RFLP cluster (OR 0.31, 95%CI 0.12-0.81, P = 0.02).

CONCLUSIONS

Although MDR-TB may have a decreased propensity to spread and cause disease, it has a profoundly negative impact on tuberculosis control.

Comparison of ceftibuten vs. amoxicillin/clavulanic acid as antibiotic prophylaxis in cholecystectomy and/or biliary tract surgery

A randomized, comparative, prospective clinical trial was carried out at a tertiary care center to compare the efficacy of two antibiotic regimens in the prophylaxis of postoperative infection in patients undergoing biliary tract surgery. One hundred patients undergoing cholecystectomy or biliary tract exploration were randomly allocated to one of the following antibiotic regimens: the standard regimen of three doses of amoxicillin/clavulanic acid (1000/200 mg) given by intravenous infusion, or a single dose of ceftibuten (400 mg) given orally. Patients were monitored during their stay in the hospital and over a 2 week period as outpatients. Fifty adult patients were included in each group. Mean age was 49 years, and sex distribution was 82 women and 18 men. The groups were comparable in terms of demographic characteristics and comorbidity. There were no cases of postoperative infection in the ceftibuten group, but five cases of infection occurred in the amoxicillin/clavulanic acid group (P < 0.05). No adverse effects were observed with either antibiotic. The treatment cost per patient was significantly lower for ceftibuten. The results indicate that ceftibuten is well tolerated and more effective than amoxicillin/clavulanic acid for prophylaxis following gallbladder and biliary tract surgery. In addition, ceftibuten has the advantage of being more cost-effective and easier to administer than amoxicillin/clavulanic acid so it could be considered as an alternative for antibiotic prophylaxis in these types of surgical procedures.