Risk factors for pulmonary tuberculosis recurrence, relapse and reinfection: a systematic review and meta-analysis

BACKGROUND

The rate of pulmonary tuberculosis (TB) recurrence is substantial. Identifying risk factors can support the development of prevention strategies.

METHODS

We retrieved studies published between 1 January 1980 and 31 December 2022 that assessed factors associated with undifferentiated TB recurrence, relapse or reinfection. For factors reported in at least four studies, we performed random-effects meta-analysis to estimate a pooled relative risk (RR). We assessed heterogeneity, risk of publication bias and certainty of evidence.

RESULTS

We included 85 studies in the review; 81 documented risk factors for undifferentiated recurrence, 17 for relapse and 10 for reinfection. The scope for meta-analyses was limited given the wide variety of factors studied, inconsistency in control for confounding and the fact that only few studies employed molecular genotyping. Factors that significantly contributed to moderately or strongly increased pooled risk and scored at least moderate certainty of evidence were: for undifferentiated recurrence, multidrug resistance (MDR) (RR 3.49; 95% CI 1.86 to 6.53) and fixed-dose combination TB drugs (RR 2.29; 95% CI 1.10 to 4.75) in the previous episode; for relapse, none; and for reinfection, HIV infection (RR 4.65; 95% CI 1.71 to 12.65). Low adherence to treatment increased the pooled risk of recurrence 3.3-fold (95% CI 2.37 to 4.62), but the certainty of evidence was weak.

CONCLUSION

This review emphasises the need for standardising methods for TB recurrence research. Actively pursuing MDR prevention, facilitating retention in treatment and providing integrated care for patients with HIV could curb recurrence rates. The use of fixed-dose combinations of TB drugs under field conditions merits further attention.

PROSPERO REGISTRATION NUMBER

CRD42018077867.

Tuberculosis Knowledge among Persons Living with HIV Attending a Tertiary Hospital in Lima, Peru

Tuberculosis (TB) is the leading cause of death among people living with HIV (PLWH). Limited TB knowledge has been associated with delayed TB diagnosis and low adherence to TB treatment. A cross-sectional study was conducted among PLWH at the largest HIV-referral center in Lima, Peru, to describe TB knowledge among PLWH and potential associated sociodemographic factors. Participants answered a self-administered survey on TB knowledge, which consisted of five questions about TB cure, transmission, treatment, symptoms, and prevention. Of 179 PLWH enrolled, most participants did not know that isoniazid (85%) and antiretrovirals (78%) are preventive measures for TB, and 56 (31.3%) knew that TB can be asymptomatic in PLWH. We did not find statistical differences in TB knowledge based on gender, education, marital status, and time on HIV care. We identified important gaps in TB knowledge among PLWH. Addressing these gaps could empower PLWH to reduce their TB risk.

Long-term impact on cardiopulmonary function and quality of life among patients recovered from SARS-CoV-2 infection in a 6-month follow-up period in Lima, Peru: FUNCTION cohort study protocol

INTRODUCTION

The sequelae of COVID-19 have been described as a multisystemic condition, with a great impact on the cardiovascular and pulmonary systems with abnormalities in pulmonary function tests, such as lower diffusing capacity of the lung for carbon monoxide (DLco) levels and pathological patterns in spirometry; persistence of radiological lesions; cardiac involvement such as myocarditis and pericarditis; and an increase in mental disorders such as anxiety and depression. Several factors, such as infection severity during the acute phase as well as vaccination status, have shown some variable effects on these post-COVID-19 conditions, mainly at a clinical level such as symptoms persistence. Longitudinal assessments and reversibility of changes across the spectrum of disease severity are required to understand the long-term impact of COVID-19.

METHODS AND ANALYSIS

A prospective cohort study aims to assess the impact of SARS-CoV-2 infection on cardiopulmonary function and quality of life after the acute phase of the disease over a 6-month follow-up period. Sample size was calculated to recruit 200 participants with confirmatory COVID-19 tests who will be subsequently classified according to infection severity. Four follow-up visits at baseline, month 1, month 3 and month 6 after discharge from the acute phase of the infection will be scheduled as well as procedures such as spirometry, DLco test, 6-minute walk test, chest CT scan, echocardiogram, ECG, N-terminal pro-B-type natriuretic peptide measurement and RAND-36 scale. Primary outcomes are defined as abnormal pulmonary function test considered as DLco <80%, abnormal cardiovascular function considered as left ventricular ejection fraction <50% and abnormal quality of life considered as a <40 score for each sphere in the RAND-36-Item Short Form Health Survey.

ETHICS AND DISSEMINATION

The study protocol was approved by the Institutional Ethics Committee of the Universidad Peruana Cayetano Heredia (SIDISI 203725) and the Ethics Committee of the Hospital Cayetano Heredia (042-2021). Protocol details were uploaded in ClinicalTrials.gov. Findings will be disseminated through peer-reviewed journals, scientific conferences and open-access social media platforms.

TRIAL REGISTRATION NUMBER

NCT05386485.

Multiomics characterization of methicillin-resistant Staphylococcus aureus (MRSA) isolates with heterogeneous intermediate resistance to vancomycin (hVISA) in Latin America

BACKGROUND

Heterogeneous vancomycin-intermediate Staphylococcus aureus (hVISA) compromise the clinical efficacy of vancomycin. The hVISA isolates spontaneously produce vancomycin-intermediate Staphylococcus aureus (VISA) cells generated by diverse and intriguing mechanisms.

OBJECTIVE

To characterize the biomolecular profile of clinical hVISA applying genomic, transcriptomic and metabolomic approaches.

METHODS

39 hVISA and 305 VSSA and their genomes were included. Core genome-based Bayesian phylogenetic reconstructions were built and alterations in predicted proteins in VISA/hVISA were interrogated. Linear discriminant analysis and a Genome-Wide Association Study were performed. Differentially expressed genes were identified in hVISA-VSSA by RNA-sequencing. The undirected profiles of metabolites were determined by liquid chromatography and hydrophilic interaction in six CC5-MRSA.

RESULTS

Genomic relatedness of MRSA associated to hVISA phenotype was not detected. The change Try38 → His in Atl (autolysin) was identified in 92% of the hVISA. We identified SNPs and k-mers associated to hVISA in 11 coding regions with predicted functions in virulence, transport systems, carbohydrate metabolism and tRNA synthesis. Further, capABCDE, sdrD, esaA, esaD, essA and ssaA genes were overexpressed in hVISA, while lacABCDEFG genes were downregulated. Additionally, valine, threonine, leucine tyrosine, FAD and NADH were more abundant in VSSA, while arginine, glycine and betaine were more abundant in hVISA. Finally, we observed altered metabolic pathways in hVISA, including purine and pyrimidine pathway, CoA biosynthesis, amino acid metabolism and aminoacyl tRNA biosynthesis.

CONCLUSIONS

Our results show that the mechanism of hVISA involves major changes in regulatory systems, expression of virulence factors and reduction in glycolysis via TCA cycle. This work contributes to the understanding of the development of this complex resistance mechanism in regional strains.

278. Long-term impact of pulmonary function among patients recovered from SARS-CoV-2 infection in Lima, Peru: a preliminary analysis of the FUNCTION cohort study

Background

Longitudinal assessment and reversibility of changes in the pulmonary function tests in the post-acute phase of COVID-19 across the whole spectrum of severity of infection is needed to understand the long-term burden of the disease.

Methods

This was a prospective cohort of symptomatic patients with a positive SARS-CoV-2 (molecular or antigenic) test. Participants were divided based on infection severity at baseline as mildly-ill (B1), moderately-ill (B2), severely-ill (B3), critically-ill (B4) (Fig.1). Follow-up consisted of 4 visits: within 7 days from discharge (BL), and at months 1 (M1), 3 (M3), and 6(M6). We report findings up to M3 for participants enrolled August 2021- March 2022. Pulmonary function capacity was assessed with carbon monoxide diffusing capacity (DLCO), spirometry, and 6-minute walk test (6MWT). A DLCO&lt; 80% was considered abnormal and reverted if &gt;80% at follow-up visits.

Study population divided by severity of infection

Results

Out of 206 eligible participants, 110 were enrolled, of which 96 (87%%), 79 (72%), and 52(47.2%) were evaluated at BL, M1, and M3, respectively (Fig.2). Most (67%) participants were male, median age was 37.5 years old (IQR: 28-46.3) and median body mass index was 26.7 (IQR:23.7-30.4). Regarding severity, 39 (41%) participants were classified as critically-ill (B4) at BL. No underlying comorbidities were reported among 63 (66%) participants, while diabetes type 2 (11%), asthma (7%) prior pulmonary tuberculosis (6%) and hypertension (5%) where the most frequent comorbidities overall; 17 (18%) reported smoking exposure. There were significant differences accross severity groups for sex, age, absence of comorbidities, and dyspnea during the acute phase of COVID-19 (Tab.1). At Of the 88 (92%) participants that underwent the pulmonary function tests at BL: 49 (56%) had DLCO &lt; 80% with a tendency to revert across B1-B4 groups at month 3 (Fig.3). Spirometry parameters (Forced Vital Capacity, Forced Expiratory Volume 1, Peak Expiratory Flow) and distance walked on 6MWT were different across groups.

Flowchart of the study population

Demographics of study population stratified by groups of severity

Median DLCO adjusted for hemoglobin value at baseline, month 1 and month 3 visits stratified by groups of severity of infection.

Conclusion

Abnormal DLCO tended to increase and revert to values greater than 80% in the 3-month follow-up period of patients recovered from SARS-CoV-2 infection across severity groups.

Disclosures

All Authors: No reported disclosures.

Detection of heterogeneous vancomycin intermediate resistance in MRSA isolates from Latin America

BACKGROUND

Vancomycin is a common first-line option for MRSA infections. The heterogeneous vancomycin-intermediate Staphylococcus aureus (hVISA) phenotype is associated with therapeutic failure. However, hVISA isolates are usually reported as vancomycin susceptible by routine susceptibility testing procedures.

OBJECTIVES

To detect and characterize the hVISA phenotype in MRSA isolates causing infections in nine Latin American countries.

METHODS

We evaluated a total of 1189 vancomycin-susceptible MRSA isolates recovered during 2006-08 and 2011-14. After an initial screening of hVISA using glycopeptide-supplemented agar strategies, the detection of hVISA was performed by Etest (GRD) and Macro-method (MET). Isolates deemed to be hVISA were subjected to population analysis profile/AUC (PAP/AUC) and WGS for further characterization. Finally, we interrogated alterations in predicted proteins associated with the development of the VISA phenotype in both hVISA and vancomycin-susceptible S. aureus (VSSA) genomes.

RESULTS

A total of 39 MRSA isolates (3.3%) were classified as hVISA (1.4% and 5.6% in MRSA recovered from 2006-08 and 2011-14, respectively). Most of the hVISA strains (95%) belonged to clonal complex (CC) 5. Only 6/39 hVISA isolates were categorized as hVISA by PAP/AUC, with 6 other isolates close (0.87-0.89) to the cut-off (0.9). The majority of the 39 hVISA isolates exhibited the Leu-14→Ile (90%) and VraT Glu-156→Gly (90%) amino acid substitutions in WalK. Additionally, we identified 10 substitutions present only in hVISA isolates, involving WalK, VraS, RpoB and RpoC proteins.

CONCLUSIONS

The hVISA phenotype exhibits low frequency in Latin America. Amino acid substitutions in proteins involved in cell envelope homeostasis and RNA synthesis were commonly identified. Our results suggest that Etest-based methods are an important alternative for the detection of hVISA clinical isolates.

The COVID-19 Pandemic in Peru: What Went Wrong?

Despite the early adoption of a national lockdown and other restrictions, Peru has been severely impacted by the COVID-19 pandemic. Having reached a milestone of more than 1,200 deaths per one million inhabitants by February 2021, important messages can be learned from how the pandemic was handled. Possible explanations for poor outcomes are a fragmented and already overwhelmed public health sector, lack of infrastructure and specialized personnel to tackle the pandemic, and deficient leadership from health authorities.

Recurrent TB: a systematic review and meta-analysis of the incidence rates and the proportions of relapses and reinfections

BACKGROUND

A recurrent tuberculosis (TB) episode results from exogenous reinfection or relapse after cure. The use of genotyping allows the distinction between both.

METHODS

We did a systematic review and meta-analysis, using four databases to search for studies in English, French and Spanish published between 1 January 1980 and 30 September 2020 that assessed recurrences after TB treatment success and/or differentiated relapses from reinfections using genotyping. We calculated person years of follow-up and performed random-effects model meta-analysis for estimating pooled recurrent TB incidence rates and proportions of relapses and reinfections. We performed subgroup analyses by clinical-epidemiological factors and by methodological study characteristics.

FINDINGS

The pooled recurrent TB incidence rate was 2.26 per 100 person years at risk (95% CI 1.87 to 2.73; 145 studies). Heterogeneity was high (I²=98%). Stratified pooled recurrence rates increased from 1.47 (95% CI 0.87 to 2.46) to 4.10 (95% CI 2.67 to 6.28) per 100 person years for studies conducted in low versus high TB incidence settings. Background HIV prevalence, treatment drug regimen, sample size and duration of follow-up contributed too. The pooled proportion of relapses was 70% (95% CI 63% to 77%; I²=85%; 48 studies). Heterogeneity was determined by background TB incidence, as demonstrated by pooled proportions of 83% (95% CI 75% to 89%) versus 59% (95% CI 42% to 74%) relapse for studies from settings with low versus high TB incidence, respectively.

INTERPRETATION

The risk of recurrent TB is substantial and relapse is consistently the most frequent form of recurrence. Notwithstanding, with increasing background TB incidence the proportion of reinfections increases and the predominance of relapses among recurrences decreases.

PROSPERO REGISTRATION NUMBER

CRD42018077867.

Adherence to standards of care and mortality in the management of Staphylococcus aureus bacteraemia in Peru: A prospective cohort study

BACKGROUND

Despite high mortality rates, physicians can alter the course of the Staphylococcus aureus bacteraemia (SAB) by following recommended standards of care. We aim to assess the adherence of these guidelines and their impact on mortality.

METHODS

Substudy from a prospective cohort of hospitalized patients with SAB from three hospitals from Peru. Hazard ratios were calculated using Cox proportional regression to evaluate the association between 30-day mortality and the performance of standards of care: removal of central venous catheters (CVC), follow-up blood cultures, echocardiography, correct duration, and appropriate definitive antibiotic therapy.

RESULTS

150 cases of SAB were evaluated; 61.33% were MRSA. 30-day attributable mortality was 22.39%. CVC removal was done in 42.86% of patients. Follow-up blood cultures and echocardiograms were performed in 8% and 29.33% of cases, respectively. 81.33% of cases had appropriate empirical treatment, however, only 22.41% of MSSA cases were given appropriate definitive treatment, compared to 93.47% of MRSA. The adjusted regression for all-cause mortality found a substantial decrease in hazards when removing CVC (aHR 0.28, 95% CI: 0.10 - 0.74) and instituting appropriate definitive treatment (aHR 0.27, 95% CI: 0.08 - 0.86), while adjusting for standards of care, qPitt bacteraemia score, comorbidities, and methicillin susceptibility; similar results were found in the attributable mortality model (aHR 0.24, 95% CI: 0.08 - 0.70 and aHR 0.21, 95% CI: 0.06 - 0.71, respectively).

CONCLUSIONS

Deficient adherence to standards of care was observed, especially definitive treatment for MSSA. CVC removal and the use of appropriate definitive antibiotic therapy reduced the hazard mortality of SAB.

Contact evaluation and isoniazid preventive therapy among close and household contacts of tuberculosis patients in Lima, Peru: an analysis of routine data

OBJECTIVE

Contacts of pulmonary tuberculosis (TB) cases are at high risk of TB infection and progression to disease. Close and household contacts and those <5 years old have the highest risk. Isoniazid preventive therapy (IPT) can largely prevent TB disease among infected individuals. International and Peruvian recommendations include TB contact investigation and IPT prescription to eligible contacts. We conducted a study in Lima, Peru, to determine the number of close and household contacts who were evaluated, started on IPT, and who completed it, and the factors associated to compliance with national guidelines.

METHODS

We conducted a longitudinal retrospective study including all TB cases diagnosed between January 2015 and July 2016 in 13 health facilities in south Lima. Treatment cards, TB registers and clinical files were reviewed and data on index cases (sex, age, smear status, TB treatment outcome), contact investigation (sex, age, kinship to the index case, evaluations at month 0, 2 and 6) and health facility (number of TB cases notified per year, proportion of TB cases with treatment success) were extracted. We tabulated frequencies of contact evaluation by contact and index case characteristics. To investigate determinants of IPT initiation and completion, we used generalised linear mixed models.

RESULTS

A total of 2323 contacts were reported by 662 index cases; the median number of contacts per case was four (IQR, 2-5). Evaluation at month 0 was completed by 99.2% (255/257) of contacts <5 and 98.1% (558/569) of contacts aged 5-19 years. Of 191 eligible contacts <5 years old, 70.2% (134) started IPT and 31.4% (42) completed it. Of 395 contacts 5-19 years old, 36.7% (145) started IPT and 32.4% (47) completed it. Factors associated to not starting IPT among contacts <5 years old were being a second-degree relative to the index case (OR 6.6 95CI% 2.6-16.5), not having received a tuberculin skin test (TST) (OR 3.9 95%CI 1.4-10.8), being contact of a smear-negative index case (OR 5.5 95%CI 2.0-15.1) and attending a low-caseload health facility (OR 2.8 95%CI 1.3-6.2). Factors associated to not starting IPT among 5-19 year-olds were age (OR 13.7 95%CI 5.9-32.0 for 16-19 vs. 5-7 years old), being a second-degree relative (OR 3.0 95%CI 1.6-5.6), not having received a TST (OR 5.4, 95%CI 2.5-11.8), being contact of a male index case (OR 2.1 95CI% 1.2-3.5), with smear-negative TB (OR 1.9 95%CI 1.0-3.6), and attending a high-caseload health facility (OR 2.1 95%CI 1.2-3.6). Factors associated to not completing IPT, among contacts who started, were not having received a TST (OR 3.4 95%CI 1.5-7.9 for <5 year-olds, and OR 4.3 95%CI 1.7-10.8 for those 5-19 years old), being contact of an index case with TB treatment outcome other than success (OR 9.3 95%CI 2.6-33.8 for <5 year-olds and OR 15.3 95%CI 1.9-125.8 for those 5-19 years old), and, only for those 5-19 years old, attending a health facility with high caseload (OR 3.2 95%CI 1.4-7.7) and a health facility with low proportion of TB cases with treatment success (OR 4.4 95%CI 1.9-10.2).

CONCLUSIONS

We found partial compliance to TB contact investigation, and identified contact, index case and health facility-related factors associated to IPT start and completion that can guide the TB programme in increasing coverage and quality of this fundamental activity.

1827. Genetic Characterization of Methicillin-Resistant Staphylococcus aureus (MRSA) Isolates Associated with the Development of Reduced Susceptibility to Vancomycin from Latin America

Background

Vancomycin (VAN) is a first-line therapeutic option for severe MRSA infections, especially in Latin America where other options are limited. However, reduced susceptibility to VAN may lead to therapeutic failures. The molecular mechanisms leading the development of VAN-intermediate S. aureus (VISA) and heterogeneous-VISA (hVISA) phenotypes are still unclear. We explored genetic signatures associated with hVISA phenotype in MRSA isolates recovered from bacteremic patients in 9 Latin American countries (2011–2014) in order to develop a genomic platform to identify these isolates.

Methods

From 538 VAN-susceptible MRSA (MIC90 = 1 µg/mL) we identified 30 hVISA isolates using GRD and macromethod E-tests; from these, 3 were confirmed by PAP-AUC. Whole-genome sequencing was performed in all 30 isolates using Illumina platform. Based on previous studies, we selected 46 genes involved in hVISA development. Multiple Blast alignments were performed using genomes of ATCC29213 and N315 (VAN-susceptible), Mu3 (hVISA) and Mu50 (VISA) as references.

Results

A total of 130 changes in 46 predicted proteins belonging to 8 functional categories were determined: 48 changes related to cell wall biogenesis, 22 to DNA/RNA processing, 17 to regulatory systems, 12 to cofactors and enzymes, 11 to membrane biosynthesis, 9 to virulence, 6 to amino acid metabolism, and 5 to transport of nitrogen and putrescine/spermidine. The most common changes identified in all the hVISA were: Y38H in Atl, N16S in PBP4, S160A in RpoB, L14I in WalK and E156G in YvqF, compared with VSSA strains. The proteins with the highest number of changes detected in the isolates confirmed by PAP-AUC were: CapP, DltA, Pbp4, TcaA, LytM (Cell wall biogenesis); MutL, RpoB (DNA/RNA processing); GraS (Regulatory systems); and PgsA (Membrane biosynthesis).

Conclusion

Changes in genes associated with cell wall biogenesis, DNA/RNA processing, regulatory systems, and membrane biosynthesis were the most prevalent in Latin American hVISA strains. Genetic signatures in genes encoding GraR (N197S), RpoB (H481Y, H481N), VraS (I5N), WalK (L14F, R222K) and MrsR (E146K) are potentially associated with this phenotype. These changes could be used to develop a platform for possible identification of hVISA isolates.

Disclosures

All Authors: No reported Disclosures.

556. Phylogenomic Epidemiology of Methicillin-Resistant Staphylococcus aureus (MRSA) Chilean-Cordobes Clone in Latin America

Background

The MRSA Chilean-Cordobes (ChC) clone belongs to the clonal complex 5 (CC5) and typically carries SCCmec I. The ChC clone predominated widely throughout several countries of Latin America (LA), but during the mid-2000s a CA-MRSA CC8 LA variant (USA300-LV) quickly replaced the ChC in Colombia and Ecuador. Most notably, this replacement was not observed in Peru or Chile. Here, we aimed to understand the phylogenomic relatedness of the CC5 ChC clone obtained from different countries of LA.

Methods

We sequenced and analyzed the genomes of 115 MRSA isolates obtained between 2011–2014 from bloodstream infections in 6 LA countries (Argentina, Brazil, Colombia, Chile, Peru, and Venezuela). All isolates were confirmed as ChC clone by pulsed-field gel electrophoresis (PFGE). We used core genome-based phylogenomic reconstructions and molecular clock analysis to infer the relationships and time of divergence between clades.

Results

Whole-genome-based multilocus sequence typing determined that 110/115 isolates belonged to ST5 and carried SCCmec I. The phylogenomic reconstruction showed ChC isolates clustered into 4 major clades distinctly segregated by country of origin (Figure 1). Interestingly, isolates recovered from Chile divided into 2 different clades that segregate according to the city of origin (Santiago [SCL] or Concepción [CON]), suggesting these clades evolved independently. Molecular clock analyses suggested all clades share a common ancestor with the divergence of the Chilean clades occurring earlier (Figure 2). Of note, analysis of heavy metal genes suggested the divergence between Chilean isolates was characterized by the loss of a mercury resistance gene cluster, which is present in an 88% of CON isolates, but only in 28% of SCL (Figure 2).

Conclusion

MRSA isolates belonging to the ChC clone from 6 LA countries clustered in 4 clades according to the geographical region of isolation. This segregation suggests divergent adaptations that may respond to different selective pressures. Heavy metal resistance could play a role in the ability of the MRSA ChC to disseminate in specific geographical locations.

Disclosures

All authors: No reported disclosures.

2176. A New Rapid Test for Detection of The Cefazolin Inoculum Effect (CIE) in Methicillin-Susceptible Staphylococcus aureus (MSSA)

Background

Most MSSA harbor one of the four different variants of β-lactamase (BlaZ) (A, B, C and D). The CIE is defined as an MIC >16 μg/mL when a high inoculum (107 CFU/mL) is used and depends on the presence of BlaZ. The presence of the CIE has been associated with therapeutic failure in invasive MSSA infections. In some countries of South America, the prevalence of CIE is high, ranging from 36% to 51% (Colombia and Argentina, respectively). Type A BlaZ is most often associated with the CIE due to its high affinity for cefazolin. Here, we developed a rapid test based on the premise that the extracellular form of BlaZ is responsible for the CIE. We aimed to identify invasive MSSA that exhibit the CIE and validate the test in two cohorts of isolates from patients in Colombia and Argentina

Methods

152 MSSA clinical isolates were collected from Colombia (n = 71) and Argentina (n = 81). We determined MIC at standard and high inoculum. We developed a test using induction of BlaZ with ampicillin (150 μg/mL) for 20 minutes and, using the supernatant for incubation with nitrocefin for 30 min. A change in color from yellow to red was considered positive. MSSA TX0117 (BlaZ +, with the CIE), ATCC 29213 (BlaZ-negative) and ATCC 25923 (BlaZ + lacking the CIE) were used as controls. BlaZ typing of all Argentinian isolates was available by sequencing

Results

A high proportion (43%) of MSSA exhibited the CIE (34% and 52% of Colombian and Argentinian isolates, respectively) by MIC. The rapid test identified 76% of isolates exhibiting the CIE and correctly ruled out all isolates lacking the CIE (sensitivity 80%, specificity 100%). Furthermore, the rapid test detected all isolates with the CIE that harbored Type A BlaZ from Argentina. Conversely, the test failed to identify the CIE in Argentinian isolates that produce type B and C BlaZ. The sensitivity and specificity of the rapid test for the Colombian isolates whose BlaZ type was unknown were 89% and 100%, respectively.

Conclusion

A rapid test of less than 2 h can readily identify MSSA isolates exhibiting the CIE. For isolates carrying type A BlaZ, which is highly associated with the CIE, the test had a sensitivity and specificity of 100%. Rapid identification of MSSA with the CIE may have important therapeutic consequences in deep-seated infections

Disclosures

All authors: No reported disclosures.

Mycobacterium tuberculosis-specific cytokine biomarkers for the diagnosis of childhood TB in a TB-endemic setting

The tuberculin skin test and interferon-gamma release assays have limitations in diagnosing tuberculosis (TB), particularly in children. This study investigated the performance of candidate M. tuberculosis-specific cytokine biomarkers for TB in children in a TB-endemic setting. A total of 237 children with a household contact with smear-positive pulmonary TB were recruited. Importantly, a group of children with illnesses other than TB (sick controls) was included to assess specificity.

Median IFN-ɣ, IL-1ra, IL-2, IL-13, IP-10, MIP-1β and TNF-α responses were significantly higher in children with active TB and latent TB infection (LTBI) than in both healthy and sick control children. Three of these cytokines – IL-2, IL-13 and IP-10 – showed better performance characteristics than IFN-ɣ, with IL-2 achieving positive and negative predictive values of 97.7% and 90.7%, respectively. Furthermore, IL-1ra and TNF-α responses differed significantly between active TB and LTBI cases, suggesting that they may be stage-specific biomarkers.

Our data indicate that incorporating these biomarkers into future blood-based TB assays could result in substantial performance gains.

Health literacy and knowledge related to tuberculosis among outpatients at a referral hospital in Lima, Peru

BACKGROUND

Tuberculosis (TB) case detection in Peru relies on passive case finding. This strategy relies on the assumption that the community is aware that a persistent cough or contact with a TB patient is an indication to seek formal health care. This study evaluated health literacy and TB knowledge among outpatients at Hospital Cayetano Heredia in Lima, Peru.

METHODS

A cross-sectional survey was performed between June and August 2017. Data on sociodemographic factors, TB knowledge, and health literacy were collected, and bivariate and multivariate logistic regressions were performed to study the associations between variables.

RESULTS

The analysis included 272 participants; 57.7% knew someone who had TB and 9% had TB in the past. A 2-week cough was reported as a TB symptom by 66 (24%) participants. High TB knowledge was found among 149 (54.8%) participants and high health literacy was found among 193 (71.0%) participants. Health literacy and TB knowledge were not significantly associated (OR=0.9; 95% CI 0.5-1.5). After controlling for sex, age, district, education, health insurance, frequency of hospital visits, and previous TB diagnosis, high TB knowledge was associated with knowing someone with TB (aOR=2.7; 95% CI 1.6-4.7) and inversely associated with being a public transport driver (aOR=0.2; 95% CI 0.05-0.9). Not living in poverty was the single factor associated with high health literacy (aOR=3.8; 95% CI 1.6-8.9).

CONCLUSION

Although TB knowledge was fair, 30% did not know that cough is a symptom of TB and >70% did not know being in contact with a TB patient is a risk factor for TB. Tailoring educational strategies to at-risk groups may enhance passive case detection especially among transport workers and TB contacts in Lima, Peru.

Staphylococcus aureus bloodstream infections in Latin America: results of a multinational prospective cohort study

Background

Substantial heterogeneity in the epidemiology and management of Staphylococcus aureus bacteraemia (SAB) occurs in Latin America. We conducted a prospective cohort study in 24 hospitals from nine Latin American countries.

Objectives

To assess the clinical impact of SAB in Latin America.

Patients and methods

We evaluated differences in the 30 day attributable mortality among patients with SAB due to MRSA compared with MSSA involving 84 days of follow-up. Adjusted relative risks were calculated using a generalized linear model.

Results

A total of 1030 patients were included. MRSA accounted for 44.7% of cases with a heterogeneous geographical distribution. MRSA infection was associated with higher 30 day attributable mortality [25% (78 of 312) versus 13.2% (48 of 363), adjusted RR: 1.94, 95% CI: 1.38-2.73, P < 0.001] compared with MSSA in the multivariable analysis based on investigators' assessment, but not in a per-protocol analysis [13% (35 of 270) versus 8.1% (28 of 347), adjusted RR: 1.10, 95% CI: 0.75-1.60, P = 0.616] or in a sensitivity analysis using 30 day all-cause mortality [36% (132 of 367) versus 27.8% (123 of 442), adjusted RR: 1.09, 95% CI: 0.96-1.23, P = 0.179]. MRSA infection was not associated with increased length of hospital stay. Only 49% of MSSA bloodstream infections (BSI) received treatment with β-lactams, but appropriate definitive treatment was not associated with lower mortality (adjusted RR: 0.93, 95% CI: 0.70-1.23, P = 0.602).

Conclusions

MRSA-BSIs in Latin America are not associated with higher 30 day mortality or longer length of stay compared with MSSA. Management of MSSA-BSIs was not optimal, but appropriate definitive therapy did not appear to influence mortality.

The Cefazolin Inoculum Effect Is Associated With Increased Mortality in Methicillin-Susceptible Staphylococcus aureus Bacteremia

Background

Recent studies have favored the use of cefazolin over nafcillin for the treatment of methicillin-susceptible Staphylococcus aureus (MSSA) bacteremia. The clinical influence of the cefazolin inoculum effect (CzIE) in the effectiveness of cephalosporins for severe MSSA infections has not been evaluated.

Methods

We prospectively included patients from 3 Argentinian hospitals with S. aureus bacteremia. Cefazolin minimum inhibitory concentrations (MICs) were determined at standard (10⁵ colony-forming units [CFU]/mL) and high (10⁷ CFU/mL) inoculum. The CzIE was defined as an increase of MIC to ≥16 µg/mL when tested at high inoculum. Whole-genome sequencing was performed in all isolates.

Results

A total of 77 patients, contributing 89 MSSA isolates, were included in the study; 42 patients (54.5%) had isolates with the CzIE. In univariate analysis, patients with MSSA exhibiting the CzIE had increased 30-day mortality (P = .034) and were more likely to have catheter-associated or unknown source of bacteremia (P = .033) compared with patients infected with MSSA isolates without the CzIE. No statistically significant difference between the groups was observed in age, clinical illness severity, place of acquisition (community vs hospital), or presence of endocarditis. The CzIE remained associated with increased 30-day mortality in multivariate analysis (risk ratio, 2.65; 95% confidence interval, 1.10–6.42; P = .03). MSSA genomes displayed a high degree of heterogeneity, and the CzIE was not associated with a specific lineage.

Conclusions

In patients with MSSA bacteremia where cephalosporins are used as firstline therapy, the CzIE was associated with increased 30-day mortality. Clinicians should be cautious when using cefazolin as firstline therapy for these infections.

HIV screening among newly diagnosed TB patients: a cross sectional study in Lima, Peru

Background

Since 2006, the Peruvian National TB program (NTP) recommends voluntary counseling and testing (VCT) for all tuberculosis (TB) patients. Responding to the differential burden of both diseases in Peru, TB is managed in peripheral health facilities while HIV is managed in referral centers. This study aims to determine the coverage of HIV screening among TB patients and the characteristics of persons not screened.

Methods

From March 2010 to December 2011 we enrolled new smear-positive pulmonary TB adults in 34 health facilities in a district in Lima. NTP staff offered VCT to all TB patients. Patients with an HIV positive result were referred for confirmation tests and management. We interviewed patients to collect their demographic and clinical characteristics and registered if patients opted in or out of the screening.

Results

Of the 1295 enrolled TB patients, nine had a known HIV diagnosis. Of the remaining, 76.1% (979) were screened for HIV. Among the 23.9% (307) not screened, 38.4% (118) opted out of the screening. TB patients at one of the health care facilities of the higher areas of the district (OR = 3.38, CI 95% 2.17–5.28 for the highest area and OR = 2.82, CI 95% 1.78–4.49 for the high area) as well as those reporting illegal drug consumption (OR = 1.65, CI 95% 1.15–2.37) were more likely not to be screened. Twenty-four were HIV positive (1.9% of all patients 1295, or 2.4% of those screened). Of 15 patients diagnosed with HIV during the TB episode, ten were enrolled in an HIV program. The median time between the result of the HIV screening and the first consultation at the HIV program was 82 days (IQR, 32–414). The median time between the result of the HIV screening and antiretroviral initiation was 148.5 days (IQR 32–500).

Conclusions

An acceptable proportion of TB patients were screened for HIV in Lima. Referral systems of HIV positive patients should be strengthened for timely ART initiation.

[Gastrointestinal tuberculosis as a cause of massive gastrointestinal bleeding in a patient with HIV infection]

Gastrointestinal tuberculosis is a rare and fatal complication in patients with HIV infection. It occurs in 3%-16% of extra pulmonary forms. The main location in 90% of cases is the ileocecal valve and colon. The most unusual presentation of gastrointestinal tuberculosis is massive bleeding with the presence of one or multiple ulcers in the colon. The diagnosis can be confirmed by biopsy and by culture of intestinal tissue. Surgical resection is the treatment of choice. We report a case of a HIV-infected patient, who did not receive antiretrovirals, and who developed disseminated tuberculosis with intestinal perforation, presenting a fatal massive intestinal bleeding.

An optimized background regimen design to evaluate the contribution of levofloxacin to multidrug-resistant tuberculosis treatment regimens: study protocol for a randomized controlled trial

Background

Current guidelines for treatment of multidrug-resistant tuberculosis (MDR-TB) are largely based on expert opinion and observational data. Fluoroquinolones remain an essential part of MDR-TB treatment, but the optimal dose of fluoroquinolones as part of the regimen has not been defined.

Methods/design

We designed a randomized, blinded, phase II trial in MDR-TB patients comparing across levofloxacin doses of 11, 14, 17 and 20 mg/kg/day, all within an optimized background regimen. We assess pharmacokinetics, efficacy, safety and tolerability of regimens containing each of these doses. The primary efficacy outcome is time to culture conversion over the first 6 months of treatment. The study aims to determine the area under the curve (AUC) of the levofloxacin serum concentration in the 24 hours after dosing divided by the minimal inhibitory concentration of the patient’s Mycobacterium tuberculosis isolate that inhibits > 90% of organisms (AUC/MIC) that maximizes efficacy and the AUC that maximizes safety and tolerability in the context of an MDR-TB treatment regimen.

Discussion

Fluoroquinolones are an integral part of recommended MDR-TB regimens. Little is known about how to optimize dosing for efficacy while maintaining acceptable toxicity. This study will provide evidence to support revised dosing guidelines for the use of levofloxacin as part of combination regimens for treatment of MDR-TB. The novel methodology can be adapted to elucidate the effect of other single agents in multidrug antibiotic treatment regimens.

Trial registration

ClinicalTrials.gov, NCT01918397. Registered on 5 August 2013.

Electronic supplementary material

The online version of this article (doi:10.1186/s13063-017-2292-x) contains supplementary material, which is available to authorized users.

A Mycoses Study Group International Prospective Study of Phaeohyphomycosis: An Analysis of 99 Proven/Probable Cases

Background

Phaeohyphomycosis is infection caused by dematiaceous, or darkly pigmented, fungi. The spectrum of disease is broad, and optimal therapy remains poorly defined. The Mycoses Study Group established an international case registry of patients with proven/probable phaeohyphomycosis with the goal of improving the recognition and management of these infections.

Methods

Patients from 18 sites in 3 countries were enrolled from 2009-2015. Cases were categorized as local superficial, local deep (pulmonary, sinus, osteoarticular infections), and disseminated infections. End points were clinical response (partial and complete) and all-cause mortality at 30 days and end of follow-up.

Results

Of 99 patients, 32 had local superficial infection, 41 had local deep infection, and 26 had disseminated infection. The most common risk factors were corticosteroids, solid organ transplantation, malignancy, and diabetes. Cultures were positive in 98% of cases. All-cause mortality was 16% at 30 days and 33% at end of follow-up, and 18 of 26 (69%) with dissemination died. Itraconazole was most commonly used for local infections, and voriconazole was used for more severe infections, often in combination with terbinafine or amphotericin B.

Conclusions

Phaeohyphomycosis is an increasingly recognized infection. Culture remains the most frequently used diagnostic method. Triazoles are currently the drugs of choice, often combined with other agents. Further studies are needed to develop optimal therapies for disseminated infections.

Diagnostic accuracy of nucleic acid amplification tests (NAATs) in urine for genitourinary tuberculosis: a systematic review and meta-analysis

Background

Genitourinary tuberculosis is the third most common form of extrapulmonary tuberculosis. Diagnosis is difficult because of unspecific clinical manifestations and low accuracy of conventional tests. Unfortunately, the delayed diagnosis impacts the urinary tract severely. Nucleic acid amplification tests yield fast results, and among these, new technologies can also detect drug resistance. There is lack of consensus regarding the use of these tests in genitourinary tuberculosis; we therefore aimed to assess the accuracy of nucleic acid amplification tests in the diagnosis of genitourinary tuberculosis and to evaluate the heterogeneity between studies.

Methods

We did a systematic review and meta-analysis of research articles comparing the accuracy of a reference standard and a nucleic acid amplification test for diagnosis of urinary tract tuberculosis. We searched Medline, EMBASE, Web of Science, LILACS, Cochrane Library, and Scopus for articles published between Jan 1, 1990, and Apr 14, 2016. Two investigators identified eligible articles and extracted data for individual study sites. We analyzed data in groups with the same index test. Then, we generated pooled summary estimates (95% CIs) for sensitivity and specificity by use of random-effects meta-analysis when studies were not heterogeneous.

Results

We identified eleven relevant studies from ten articles, giving information on PCR, LCR and Xpert MTB/RIF tests. All PCR studies were “in-house” tests, with different gene targets and had several quality concerns therefore we did not proceed with a pooled analysis. Only one study used LCR. Xpert studies were of good quality and not heterogeneous, pooled sensitivity was 0·87 (0·66–0·96) and specificity was 0·91 (0·84–0·95).

Conclusion

PCR studies were highly heterogeneous. Among Xpert MTB/RIF studies, specificity was favorable with an acceptable confidence interval, however new studies can update meta-analysis and get more precise estimates. Further high-quality studies are urgently needed to improve diagnosis of genitourinary tuberculosis.

Protocol registration

PROSPERO CRD42016039020.

Electronic supplementary material

The online version of this article (doi:10.1186/s12879-017-2476-8) contains supplementary material, which is available to authorized users.

Factors associated with early mycological clearance in HIV-associated cryptococcal meningitis

INTRODUCTION

The first-line combination therapy for HIV-associated cryptococcal meningitis (CM), a condition of high mortality particularly in the first two weeks of treatment, consists of amphotericin B plus flucytosine (5-FC). Given that 5-FC remains unavailable in many countries, the knowledge of factors influencing mycological clearance in patients treated with second-line therapy could contribute to effective management.

OBJECTIVES

To determine the factors associated with the clearance of Cryptococcus sp. from the cerebrospinal fluid by the second week of effective antifungal therapy (early mycological clearance) in HIV-associated CM.

METHODS

Retrospective cohort study based on secondary data corresponding to HIV-associated CM cases hospitalized at a tertiary health care center in Lima, Peru where 5-FC remains unavailable. Risk factors associated with early mycological clearance were analyzed by generalized linear regression models.

RESULTS

From January 2000 to December 2013, 234 individuals were discharged with a diagnosis of HIV-associated CM; in 215 we retrieved the required data. The inpatient mortality was 20% (43/215), 15 of them in the first two weeks of treatment. In the final model (157 cases), adjusted for age, previous episode of CM, ART use, type of antifungal treatment, raised intracranial pressure, frequency of therapeutic lumbar punctures, baseline fungal burden and treatment period, the factors associated with early mycological clearance were: Amphotericin B deoxycholate plus fluconazole as combination therapy (RR, 1.56; 95% CI, 1.14-2.14); severe baseline intracranial pressure (≥35 cm H2O) (RR, 0.57; 95% CI, 0.33-0.99); and baseline fungal burden over 4.5 log10 CFU/mL (RR, 0.61 95% CI: 0.39-0.95).

CONCLUSIONS

In a setting without access to first-line therapy for CM, the combination therapy with amphotericin B deoxycholate plus fluconazole was positively associated with early mycological clearance, while high fungal burden and severe baseline intracranial pressure were negatively associated, and thus related to failure.

Oxacillin-Resistant and Multidrug-Resistant Staphylococcus aureus in Lima, Peru

In a hospital in Lima, Peru, a review of 103 Staphylococcus aureus infections was conducted during 2002. The prevalence of oxacillin-resistant S. aureus strains was 68%; 25% of strains were resistant to multiple drugs. Previous use of antibiotics and undergoing a surgical procedure during the current hospital stay were associated with the presence of an oxacillin-resistant S. aureus strain.

A prospective longitudinal study of tuberculosis among household contacts of smear-positive tuberculosis cases in Lima, Peru

Background

Household contacts (HHCs) of TB cases are at increased risk for TB disease compared to the general population but the risk may be modified by individual or household factors. We conducted a study to determine incident TB among HHCs over two years after exposure and to identify individual and household level risk factors.

Methods

Adults newly diagnosed with a first episode of smear-positive pulmonary TB (index cases) between March 2010 and December 2011 in eastern Lima, were interviewed to identify their HHC and household characteristics. TB registers were reviewed for up to two years after the index case diagnosis and house visits were made to ascertain TB cases among HHC. The TB incidence rate ratio among HHCs as a function of risk factors was determined using generalized linear mixed models.

Results

The 1178 index cases reported 5466 HHCs. In 402/1178 (34.1 %) households, at least one HHC had experienced a TB episode ever. The TB incidence among HHCs was 1918 (95%CI 1669–2194) per 100,000 person-years overall, and was 2392 (95%CI 2005–2833) and 1435 (95%CI 1139–1787) per 100,000 person-years in the first and second year, respectively. Incident TB occurred more than six months following the index case’s TB diagnosis in 121/205 (59.0 %) HHCs. In HHCs, bacillary load and time between symptoms and treatment initiation in the index case, as well as the relationship to the index case and the sex of the HHC all had a significant association with TB incidence in HHCs.

Conclusions

Incidence of TB among HHCs was more than ten times higher than in the general population. Certain HHC and households were at higher risk of TB, we recommend studies to compare HHC investigation to households at highest risk versus current practice, in terms of efficiency.

Electronic supplementary material

The online version of this article (doi:10.1186/s12879-016-1616-x) contains supplementary material, which is available to authorized users.

Characterization and Clinical Impact of Bloodstream Infection Caused by Carbapenemase-Producing Enterobacteriaceae in Seven Latin American Countries

Introduction

Infections caused by carbapenem-resistant Enterobacteriaceae are a public health problem associated with higher mortality rates, longer hospitalization and increased healthcare costs. We carried out a study to describe the characteristics of patients with carbapenemase-producing Enterobacteriaceae (CPE) and non-CPE bloodstream infection (BSI) from Latin American hospitals and to determine the clinical impact in terms of mortality and antibiotic therapy.

Methods

Between July 2013 and November 2014, we conducted a multicenter observational study in 11 hospitals from 7 Latin American countries (Argentina, Colombia, Ecuador, Guatemala, Mexico, Peru, Venezuela). Patients with BSI caused by Enterobacteriaceae were included and classified either as CPE or non-CPE based on detection of bla_KPC, bla_VIM, bla_IMP, bla_NDM and bla_OXA-48 by polymerase chain reaction.

Enrolled subjects were followed until discharge or death. Demographic, microbiological and clinical characteristics were collected from medical records. Both descriptive and inferential statistics were used to analyze the information.

Results

A total of 255 patients with Enterobacteriaceae BSI were included; CPE were identified in 53 of them. In vitro non-susceptibility to all screened antibiotics was higher in the patients with CPE BSI, remaining colistin, tigecycline and amikacin as the most active drugs. Combination therapy was significantly more frequent in the CPE BSI group (p < 0.001). The most common regimen was carbapenem + colistin or polymyxin B. The overall mortality was 37% (94/255). Overall and attributable mortality were significantly higher in patients with CPE BSI (p < 0.001); however, we found that patients with CPE BSI who received combination therapy and those who received monotherapy had similar mortality. After multivariate adjustment, CPE BSI (adjusted odds ratio [aOR] 4; 95% confidence interval [CI] 1.7–9.5; p = 0.002) and critical illness (aOR 6.5; 95% CI 3.1–13.7; p < 0.001) were independently associated with in-hospital mortality.

Conclusions

This study provides valuable data on the clinical characteristics and mortality risk factors in patients with CPE BSI. We determined that CPE infection is an independent mortality predictor and thus Latin American hospitals should perform campaigns on prevention and control of CPE BSI.

Manual MGIT™ system for the detection of Mycobacterium tuberculosis: insights from a high TB burden setting

OBJECTIVE

To evaluate the diagnostic performance of manual MGIT™ (MMGIT) compared to the gold standard, Löwenstein-Jensen (LJ), in the diagnosis of pulmonary tuberculosis (TB) in a high-burden setting.

METHODS

Individuals with suspected TB enrolled in parallel diagnostic trials during 2007-2011 were included. Two samples were obtained from each patient and inoculated into MMGIT and LJ medium. Diagnostic tests were performed, and the incremental yield of a second test and time to detection (TTD) were calculated. Analyses were performed per patient and per sample. Gold standard was based on LJ culture.

RESULTS

In the per patient and per sample analysis, we evaluated 1436 patients and 4142 samples. The sensitivity and specificity for smear and MMGIT per sample were respectively 89.9%/92.2% and 97.1%/98.9%. Contamination was observed in 1.4% of samples on MMGIT. The mean TTD (days) was 11.8 for MMGIT and 22.9 for LJ. The sensitivity and specificity for smear and MMGIT per patient were respectively 89.9% and 92.2% and 97.1% and 98.3%. A second MMGIT culture had an incremental yield of 1.6%.

CONCLUSIONS

MMGIT has high sensitivity and specificity, regardless of smear result, with a 50% reduction in TTD compared to LJ. These features make MMGIT an acceptable TB diagnostic method for use in resource-limited settings.

Prevalence, Risk Factors, and Treatment Outcomes of Isoniazid- and Rifampicin-Mono-Resistant Pulmonary Tuberculosis in Lima, Peru

Background

Isoniazid and rifampicin are the two most efficacious first-line agents for tuberculosis (TB) treatment. We assessed the prevalence of isoniazid and rifampicin mono-resistance, associated risk factors, and the association of mono-resistance on treatment outcomes.

Methods

A prospective, observational cohort study enrolled adults with a first episode of smear-positive pulmonary TB from 34 health facilities in a northern district of Lima, Peru, from March 2010 through December 2011. Participants were interviewed and a sputum sample was cultured on Löwenstein-Jensen (LJ) media. Drug susceptibility testing was performed using the proportion method. Medication regimens were documented for each patient. Our primary outcomes were treatment outcome at the end of treatment. The secondary outcome included recurrent episodes among cured patients within two years after completion of the treatment.

Results

Of 1292 patients enrolled, 1039 (80%) were culture-positive. From this subpopulation, isoniazid mono-resistance was present in 85 (8%) patients and rifampicin mono-resistance was present in 24 (2%) patients. In the multivariate logistic regression model, isoniazid mono-resistance was associated with illicit drug use (adjusted odds ratio (aOR) = 2.10; 95% confidence interval (CI): 1.1–4.1), and rifampicin mono-resistance was associated with HIV infection (aOR = 9.43; 95%CI: 1.9–47.8). Isoniazid mono-resistant patients had a higher risk of poor treatment outcomes including treatment failure (2/85, 2%, p-value<0.01) and death (4/85, 5%, p<0.02). Rifampicin mono-resistant patients had a higher risk of death (2/24, 8%, p<0.01).

Conclusion

A high prevalence of isoniazid and rifampicin mono-resistance was found among TB patients in our low HIV burden setting which were similar to regions with high HIV burden. Patients with isoniazid and rifampicin mono-resistance had an increased risk of poor treatment outcomes.

Implementation of a stepped-wedge cluster randomized design in routine public health practice: design and application for a tuberculosis (TB) household contact study in a high burden area of Lima, Peru

Background

We designed a pragmatic stepped-wedge cluster randomized controlled trial in order to evaluate provider-initiated evaluation of household contacts (HCs) of smear positive tuberculosis (TB) cases within a routine TB program in Lima, Peru.

Methods/Design

National TB program (NTP) officers of San Juan de Lurigancho District (Lima, Peru) and university-based researchers jointly designed a pragmatic stepped-wedge cluster randomized trial design in order to evaluate a planned active case finding (ACF) program for all HCs of smear-positive TB cases in 34 district healthcare centres. Randomization of time to intervention initiation was stratified by health centre TB case rate. The ACF intervention included provider-initiated home visits of all new sputum smear positive TB patients in order to evaluate household contacts for active TB. Active TB was diagnosed using symptom screening, sputum screening, chest x-ray and clinical evaluation. Once initiated, ACF was provided by NTP staff and integrated into the routine DOTS TB program activities.

Discussion

This study protocol describes the pragmatic stepped-wedge cluster randomized trial of active household contact evaluations within an NTP. The stepped-wedge design met overlapping needs of local TB programmers and researchers to adequately evaluate the large-scale roll out of a new control program in a TB endemic setting. Multiple planning meetings were required to develop the necessary networks and in order to understand the operations, needs and goals of the NTP staff and researchers collaborating on this project. The advantages and challenges of using this study design in practice and within existing routine TB programs in a middle-income country context are discussed.

Trial registration

ClinicalTrials.gov NCT02174380. Registered 24 Jun 2014

Geographic predictors of primary multidrug-resistant tuberculosis cases in an endemic area of Lima, Peru

SETTING

Peru reports among the highest multidrug-resistant tuberculosis (MDR-TB) rates in the Americas, with a growing proportion in previously untreated tuberculosis (TB) cases. The identification of clusters of primary MDR-TB compared with drug-susceptible TB (DS-TB) could help prioritize interventions.

OBJECTIVE

To examine the clustering of primary MDR-TB case residences and their proximity to high-risk locations in San Juan de Lurigancho District, Lima, Peru.

DESIGN

Enrolled primary MDR-TB and primary DS-TB cases were interviewed and their primary residence was recorded using handheld Global Positioning System devices. Kuldorff's spatial scan statistic was used for cluster detection (SaTScan(TM), v. 9.1.1). Identified clusters were visualized in Quantum Geographic Information Systems software (v1.8.0). The following cluster centers were tested: a health centre with the highest TB and MDR-TB rates (Clinic X), a hospital and two prisons. Using regression analyses, we examined predictors of primary MDR-TB cases.

RESULTS

A statistically significant cluster of primary MDR-TB cases was identified within a 2.29 km radius around Clinic X. Proximity to Clinic X remained a significant predictor of primary MDR-TB in adjusted regression analyses.

CONCLUSION

We identified a hotspot of primary MDR-TB cases around Clinic X in a TB-endemic area. Causes of this clustering require investigation; targeted interventions for this high-risk area should be considered.

Patient Characteristics Associated with Tuberculosis Treatment Default: A Cohort Study in a High-Incidence Area of Lima, Peru

Background

Although tuberculosis (TB) is usually curable with antibiotics, poor adherence to medication can lead to increased transmission, drug resistance, and death. Prior research has shown several factors to be associated with poor adherence, but this problem remains a substantial barrier to global TB control. We studied patients in a high-incidence district of Lima, Peru to identify factors associated with premature termination of treatment (treatment default).

Methods

We conducted a prospective cohort study of adult smear-positive TB patients enrolled between January 2010 and December 2011 with no history of TB disease. Descriptive statistics and multivariable logistic regression analyses were performed to determine risk factors associated with treatment default.

Results

Of the 1233 patients studied, 127 (10%) defaulted from treatment. Patients who defaulted were more likely to have used illegal drugs (OR = 4.78, 95% CI: 3.05-7.49), have multidrug-resistant TB (OR = 3.04, 95% CI: 1.58-5.85), not have been tested for HIV (OR = 2.30, 95% CI: 1.50-3.54), drink alcohol at least weekly (OR = 2.22, 95% CI: 1.40-3.52), be underweight (OR = 2.08, 95% CI: 1.21-3.56), or not have completed secondary education (OR = 1.55, 95% CI: 1.03-2.33).

Conclusions

Our study identified several factors associated with defaulting from treatment, suggesting a complex set of causes that might lead to default. Addressing these factors individually would be difficult, but they might help to identify certain high-risk patients for supplemental intervention prior to treatment interruption. Treatment adherence remains a barrier to successful TB care and reducing the frequency of default is important for both the patients’ health and the health of the community.

Public transportation and tuberculosis transmission in a high incidence setting

Background

Tuberculosis (TB) transmission may occur with exposure to an infectious contact often in the setting of household environments, but extra-domiciliary transmission also may happen. We evaluated if using buses and/or minibuses as public transportation was associated with acquiring TB in a high incidence urban district in Lima, Peru.

Methods

Newly diagnosed TB cases with no history of previous treatment and community controls were recruited from August to December 2008 for a case-control study. Crude and adjusted odd ratios (OR) and 95% confidence intervals (CI) were calculated using logistic regression to study the association between bus/minibus use and TB risk.

Results

One hundred forty TB cases and 80 controls were included. The overall use of buses/minibuses was 44.9%; 53.3% (72/135) among cases and 30.4% (24/79) among controls [OR: 3.50, (95% CI: 1.60–7.64)]. In the TB group, 25.7% (36/140) of subjects reported having had a recent household TB contact, and 13% (18/139) reported having had a workplace TB contact; corresponding figures for controls were 3.8% (3/80) and 4.1% (3/73), respectively[OR: 8.88 (95% CI: 2.64–29.92), and OR: 3.89 (95% CI: 1.10–13.70)]. In multivariate analyses, age, household income, household contact and using buses/minibuses to commute to work were independently associated with TB [OR for bus/minibus use: 11.8 (95% CI: 1.45–96.07)].

Conclusions

Bus/minibus use to commute to work is associated with TB risk in this high-incidence, urban population in Lima, Peru. Measures should be implemented to prevent TB transmission through this exposure.

Time to initiation of multidrug-resistant tuberculosis treatment and its relation with outcome in a high incidence district in Lima, Peru

OBJECTIVE

To determine the time from diagnosis to start of multidrug resistant tuberculosis (MDR TB) treatment in Lima, Peru.

METHODS

We studied new smear-positive TB adults that were started on MDR TB treatment or that were switched to it between June 2008 and December 2011.

RESULTS

Time from the first positive smear to MDR-TB treatment was >30 days in 35% (13/37) of patients. Among the 27% (24/88) of patients that switched to MDR-TB treatment, time from the last dose of a drug-susceptible regimen was >30 days.

CONCLUSION

Start of and switching to MDR TB treatment is still delayed.