Bactericidal killing of meningococcal W strains isolated in Argentina by the sera of adolescents and infants immunized with 4-component meningococcal serogroup B vaccine (4CMenB)

Invasive meningococcal disease (IMD) is a life-threatening disease caused by meningococcal serogroups A, B, C, W, X, and Y, of which B and W are most common in Argentina. The 4-component meningococcal serogroup B (4CMenB) vaccine contains three purified recombinant protein antigens (Neisseria adhesin A [NadA], factor H binding protein [fHbp], and Neisserial Heparin Binding Antigen [NHBA]) and outer membrane vesicles (OMV), which is derived from the New Zealand epidemic strain and contains Porin A 1.4. These antigens are present and conserved in strains that belong to other serogroups. In this study, we show that 10/11 (91%) meningococcal serogroup W (MenW) strains selected to be representative of MenW isolates that caused IMD in Argentina during 2010-2011 were killed in bactericidal assays by the sera of adolescents and infants who had been immunized with the 4CMenB vaccine. We also show that MenW strains that caused IMD in Argentina during 2018-2021 were genetically similar to the earlier strains, indicating that the 4CMenB vaccine would likely still provide protection against current MenW strains. These data highlight the potential of 4CMenB vaccination to protect adolescents and infants against MenW strains that are endemic in Argentina.

Meningococcal burden of disease in Argentina: 10 years epidemiologic review

Invasive meningococcal disease (IMD) is an uncommon but serious and potentially fatal condition, mainly affecting infants. In 2017, Argentina introduced a vaccination program against serogroups A, C, W and Y (MenACWY) for infants aged 3, 5 and 15 months and adolescents aged 11 years. The objective of this study was to review the burden of IMD in Argentina in 2010-2019. Data were obtained from national surveillance databases, and the study estimated IMD incidence, mortality, case-fatality rates, and serogroup distributions across age groups. A total of 1,972 IMD cases were reported in the study period, with the highest incidence in infants aged < 1 year. Incidence peaked in 2013 and subsequently declined. Mortality rates were 18 times higher in infants than in other age groups, reflecting the high impact of IMD in this age group. The case-fatality rate was 8.5% on average and increased with age. The proportion of notified cases with serogroup identification increased over the period, reaching 91% in 2019. The most common serogroups over the study period were serogroup B (48%) and serogroup W (42%), with an increase in B relative to W since 2015. In infants aged < 1 year, the proportion of serogroup B increased in recent years, reaching around 70% of characterized cases in 2018-2019. These results show the dynamism of IMD and indicate the importance of vaccination at an early age and offering protection against predominant serogroups. These data are valuable to support evidence-based decision-making in healthcare.

2047. Meningococcal burden of disease in Argentina: 10 years epidemiologic review

Background

Reduction of Invasive meningococcal disease (IMD) burden is one of the public health main priorities in Argentina. Since 2017, MenACWY vaccination was implemented for infants (3-5 and 15 months) and adolescents (11 years). However, epidemiological studies have been scarce in recent years. Considering the changing dynamic of the disease, specially related to serogroups circulation, we decided to carry out an epidemiological review and update IMD information that contributes to assess the best prevention strategy.

Methods

Retrospective 2010-2019 observational and descriptive study, based on Argentina Ministry of Health secondary data. Main outcomes included IMD incidence rates, serogroups distribution, mortality and case fatality ratios (CFR) stratified by year, age groups, (infants: 0-11 months; 1 to 4 y; 5 to 19 y; &gt;20 to 29 y; &gt;30 to 39 y; 40 to 49 y; 50 to 59 y; &gt;60 y) and regions.

Results

1,972 IMD cases were notified in the study period. Incidence reached its maximum in 2013 (0.69/100,000) and steadily declined to 0.22-0.23/100,000 in 2018-2019. Highest incidence rates were observed in infants (exceeding 14/100,000 in 2012, with no adolescent’s peak) and in the center of the country (reaching a value of 0.9/100,000 in 2013). There were 167 meningococcal deaths during 2010-2019 with a downtrend since 2014. Mortality rates were 18 times higher in infants versus all other age groups. CFR for the entire period was 8.5% and increased with age (&lt; 7% in &lt; 20y to 26% in &gt;60y). Serogroup identification from notified cases increased from 73% in 2010 to 91% in 2019. From all characterized strains 47% and 42% corresponded to serogroup B and W, respectively. A higher predominance of serogroup B over W was observed during the last 5 years, especially in infants and in the central region.

Conclusion

The highest burden of meningococcal disease focused on children &lt; 1yoa with a growing predominance of serogroup B. This trend highlights the importance of vaccination at very early age adding protection against serogroup B in this age group. These results will contribute to the process of evidence-based decision making.

Disclosures

Analia urueña, n/a, MSD: Grant/Research Support|Received funding for investigator led studies from GSK,: Advisor/Consultant|Received funding for investigator led studies from GSK,: Grant/Research Support|Received funding for investigator led studies from GSK,: Honoraria|Sanofi: Grant/Research Support|Seqirus: Advisor/Consultant|Seqirus: Grant/Research Support|Takeda: Grant/Research Support Maria Eugenia Pannunzio, n/a, GSK Argentina: Employee María Seoane, n/a, GSK: Board Member|GSK: Stocks/Bonds Jorge Gómez, n/a, GlaxoSmithKline: Employee|GlaxoSmithKline: Stocks/Bonds Norberto Giglio, GSK: Grant/Research Support|GSK: Honoraria|Received funding for investigator led studies from GSK,: Grant/Research Support|Received funding for investigator led studies from GSK,: Honoraria|SANOFI: Grant/Research Support|SANOFI: Honoraria|Sequirus: Grant/Research Support|Sequirus: Honoraria.

Laboratory surveillance of invasive Haemophilus influenzae disease in Argentina, 2011-2019

The incorporation of Haemophilus influenzae type b (Hib) vaccine into the Argentine National Immunization Program in 1998 resulted in a dramatic decrease in the incidence of invasive disease due to this serotype. We assessed 1405 H. influenzae (Hi) isolates causing invasive infections referred to the National Reference Laboratory between 2011 and 2019. Non-encapsulated Hi were the most common strains (44.5%), followed by types b (41.1%) and a (10.0%). Significant increase in the proportion of type b was observed, from 31.2% in 2011, to 50% in 2015, correlating with the peak incidence rate, later decreasing to 33.6% by 2019. We compared the genetic relationship between clones circulating during the period of increased Hib incidence (2011-2015) and those of the prevaccination-transition period (1997-1998). Four pulsotypes predominated in both periods, G, M, P and K, G being the most common. Multi-locus sequence typing revealed that the 4 pulsotypes belonged to ST6, or one of its simple or double locus variants. Isolates from fully vaccinated individuals did not differ from those of the rest of the population studied. After ruling out aspects associated with emergence of specific clones, we concluded that factors such as low booster coverage rates, delayed vaccination schedules and use of different vaccines may have contributed to the reemergence of Hib infections.

Oropharyngeal meningococcal carriage in children and adolescents, a single center study in Buenos Aires, Argentina

Background

Neisseria meningitidis (Nm) pharyngeal carriage is a necessary condition for invasive disease. We present the first carriage study in children in Buenos Aires, Argentina, considering 2017 as a transition year. Aims: to assess the rate of Nm carriage, to determine genogroup, clonal complex and outer membrane protein distribution, to determine carriage risk factors by age.

Methods

Cross-sectional study including children 1–17 yrs, at Ricardo Gutiérrez Children’s Hospital in Buenos Aires 2017. Oro-pharyngeal swabs were taken and cultured within a short time after collection. Genogroup was determined by PCR and clonal complex by MLST. Categorical variables were analyzed.

Results

A total of 1,751 children were included. Group 1: 943 children 1–9 yrs, 38 Nm were isolated; overall carriage 4.0%. Genogroup distribution: B 26.3%, W 5.3%, Y 2.6%, Z 5.3%, other groups 7.9% and capsule null (cnl) 52.6%. Participating in extracurricular activities was the only independent predictor of Nm carriage. Group 2: 808 children 10–17 yrs, 76 Nm were isolated; overall carriage 9.4%. Genogroup distribution: B 19.7%, C 5.3%, W 7.9%, Y 9.2%, Z 5.3%, other groups 7.9% and cnl 44.7%. Independent predictors of carriage: attending pubs/night clubs and passive smoking (adjusted OR: 0.55, 95%CI = 0.32–0.93; p = 0.025).

Conclusions

Overall carriage was higher in 10–17 yrs. The isolates presenting the cnl locus were prevalent in both age groups and genogroup B was the second most frequent.

1519. Identification of Neisseria meningitidis (Nn) Nasopharyngeal Carriage Among Non-Vaccinated Children and Isolations in Invasive Disease (ID) Cases in Argentina 2017

Background

Neisseria meningitides (Nm) cause different types of invasive infections.Nm pharyngeal carriage is a necessary condition for invasive meningococcal disease. In 2017 Argentina introduced a tetravalent meningococcal conjugated vaccine (MenACYW) to the National Immunization Program.Aims To assess the rate of Nm carriage in healthy children and adolescents attending a public hospital in Buenos Aires city, to determine genogroup and clonal complex distribution,to describe genogroup distribution of Nm isolated from ID in Argentina, during the same period.

Methods

Between March and December 2017, a single-center, cross-sectional study was performed among 1,751 children 1–17 years old attending Ricardo Gutiérrez Children Hospital in Buenos Aires, Argentina. From oro-pharyngeal swabs, genogroup and clonal complex (CC) were identified. We analyzed Nm ID genogroups data reported to the Regional Surveillance Program (SIREVA II) in the same year. at the same period were relevated.

Results

114Nm were isolated from the carriage study, with an overall carriage of 6.5%.Genogroups distribution: B 25(21.9%), W 9(7.8%), Y 7(6.1%), Z 6(5.2%), C 4(3.5%), non-groupable 9(7.8%) and non-capsulated (NC)54 (47.3%). 105 Clonal complex (CC) were determined: Genogroup B isolates belonged to ST-41/44, ST-35, ST-32 and ST-865. Genogroup W was associated to ST-11 and ST-35. SIREVA reported 76 strains of Nminvasive infections in 2017, 53.9% meningitis, 11.8% meningitis and sepsis, 22.4% sepsis, and 11.8% others. Genogroupsdistribution: B59.2% (45), W 23.6% (18), C 10.5% (8), Y 6.5% (5).

Conclusion

Genogroup B is the most frequent cause of ID followed by W in our country. In the pharyngeal carriage study we found that NmNC was prevalent and genogroup B was the most frequent among the encapsulated.Genogroup B CCs detected in our carriage study coincided with those found previously in ID in Argentina. Genogroup W carriage was low and hypervirulent CC ST-11 was detected. Although genogroup Z does not cause ID in our country it was found in carriage.

Disclosures

All authors: No reported disclosures.

2315. Neisseria meningitidis Oro-Pharyngeal Carriage, Serogroups and Clonal Complex in Children and Adolescents in Argentina

Background

Neisseria meningitidis (Nm) pharyngeal carriage is a necessary condition for invasive meningococcal disease. In 2017, Argentina introduced a tetravalent meningococcal conjugated vaccine (MenACYW) to the National Immunization Program for children. We present the first carriage study in children in the prevaccine era. Aims: 1) to assess the rate of Nm carriage in healthy children and adolescents attending a public hospital in Buenos Aires city; 2) to determine serogroup and clonal complex distribution; 3)to determine carriage risk factors by age.

Methods

Cross-sectional study including children 1–17 years, stratified in two age groups (1–9 years and 10–17 years) assisted at Ricardo Gutiérrez Children Hospital between March-December 2017. Oro-pharyngeal swabs were plated and meningococci identified by conventional microbiology methods. Serogroup was determined by PCR. Clonal complex was determined by MLST.

Results

A total of 1751 children were included. Group aged 1–9 years: 38 Nm were isolated from 943 samples collected: overall carriage 4.0%. Serogroups distribution: B 26.3%, Y 2.6%, W 5.3%, Z 5.3%, non-groupable 7.9% and non-capsulated 52.6%. Clonal complex was determined for 25 isolates. Attendance at social venues was the only independent predictor of Nm carriage (adjusted OR: 2.02, CI 95% = 1.01–4.03; P = 0.04). Group aged 10–17 years: 76 Nm were isolated from 808 samples: overall carriage 9.4%. Serogroups distribution: B 19.7%, C 5.3%, W 7.9%, Y 9.2%, Z 5.3%, non-groupable 7.9% and non-capsulated 44.7%. Clonal complex was determined for 58 isolates. Independent predictor of Nm carriage: attendance at night clubs (adjusted OR: 3.38, CI95% = 1.28–8.93; P = 0.013); passive smoking at home (adjusted OR: 0.55, CI 95% = 0.32–0.93; P = 0.025). Preliminary data show a total of 10 different clonal complexes present among all serogroups in the 1–9 years group aged and 13 in 10–17 years.

Conclusion

Overall carriage was higher in the 10–17 years population. The non-encapsulated Nm was prevalent in both groups and serogroup B was the most frequent among the encapsulated. The results demonstrated a high diversity of N. meningitis in pharyngeal carriage.

Disclosures

All authors: No reported disclosures.

Two-stage activity-safety study of daily rifapentine during intensive phase treatment of pulmonary tuberculosis

BACKGROUND

Rifapentine (RPT) has potent activity against Mycobacterium tuberculosis; however, the optimal dose for anti-tuberculosis treatment is unknown.

OBJECTIVE

To determine the antimicrobial activity, safety and tolerability of RPT 450 mg or 600 mg administered daily during the first 8 weeks of treatment for pulmonary tuberculosis (TB).

DESIGN

In a two-stage, randomised open-label study, adults with sputum smear-positive TB were randomised to receive RPT 450 mg, RPT 600 mg or rifampicin (RMP) 600 mg daily for 8 weeks with isoniazid, pyrazinamide and ethambutol. The primary endpoint was sputum culture status on Löwenstein-Jensen (LJ) medium at completion of 8 weeks of treatment.

RESULTS

A total of 153 participants were enrolled. Both RPT regimens met pre-specified criteria to advance to stage 2. At completion of 8 weeks of treatment, LJ culture conversion occurred in 85% (35/41), 96% (43/45) and 94% (34/36) of participants in the RPT 450 mg, RPT 600 mg and RMP groups, respectively. The proportions of participants discontinuing treatment were similar (respectively 1/54 [2.0%], 1/51 [2.0%] and 4/48 [8.3%] in the RPT 450 mg, RPT 600 mg and RMP groups), as were ⩾grade 3 adverse events (0/54 [0%], 1/51 [2.0%] and 4/48 [8.3%]).

CONCLUSIONS

There was a trend towards greater efficacy with RPT 600 mg than with RPT 450 mg. Daily RPT was safe and well-tolerated.

Phenotypic and genotypic characteristics of Neisseria meningitidis disease-causing strains in Argentina, 2010

Phenotypic and genotypic characterization of 133 isolates of Neisseria meningitidis obtained from meningococcal disease cases in Argentina during 2010 were performed by the National Reference Laboratory as part of a project coordinated by the PAHO within the SIREVA II network. Serogroup, serotype, serosubtype and MLST characterization were performed. Minimum Inhibitory Concentration to penicillin, ampicillin, ceftriaxone, rifampin, chloramphenicol, tetracycline and ciprofloxacin were determined and interpreted according to CLSI guidelines. Almost 49% of isolates were W135, and two serotype:serosubtype combinations, W135:2a:P1.5,2:ST-11 and W135:2a:P1.2:ST-11 accounted for 78% of all W135 isolates. Serogroup B accounted for 42.1% of isolates, and was both phenotypically and genotypically diverse. Serogroup C isolates represented 5.3% of the dataset, and one isolate belonging to the ST-198 complex was non-groupable. Isolates belonged mainly to the ST-11 complex (48%) and to a lesser extent to the ST-865 (18%), ST-32 (9,8%) and the ST-35 complexes (9%). Intermediate resistance to penicillin and ampicillin was detected in 35.4% and 33.1% of isolates respectively. Two W135:2a:P1.5,2:ST-11:ST-11 isolates presented resistance to ciprofloxacin associated with a mutation in the QRDR of gyrA gene Thr91-Ile. These data show serogroup W135 was the first cause of disease in Argentina in 2010, and was strongly associated with the W135:2a:P1.5,2:ST-11 epidemic clone. Serogroup B was the second cause of disease and isolates belonging to this serogroup were phenotypically and genotypically diverse. The presence of isolates with intermediate resistance to penicillin and the presence of fluorquinolone-resistant isolates highlight the necessity and importance of maintaining and strengthening National Surveillance Programs.

Tuberculosis incidence among contacts of active pulmonary tuberculosis

BACKGROUND

Treatment of latent tuberculosis (TB) infection (LTBI) in Brazil is recommended only in the case of contacts of pulmonary smear-positive TB patients aged<or=15 years with a tuberculin skin test (TST)>or=10 mm and no previous bacille Calmette-Guérin (BCG) vaccination or with a TST>or=15 mm regardless of previous BCG vaccination.

OBJECTIVE

To evaluate the 2-year incidence and predictors of TB among contacts who did not meet the Brazilian criteria for LTBI treatment.

DESIGN

Retrospective cohort study. Contacts aged between 12 and 15 years and those aged>or=15 years who did not meet the Brazilian criteria for LTBI treatment were enrolled in the study.

RESULTS

TB incidence was 3.2% (22/667), with an estimated TB rate of 1649 per 100000 population. Risk of TB was greater among the 349 contacts with TST>or=5 mm (5.4%) compared to the 318 contacts with TST<5 mm (0.9%; RR 6.04, 95%CI 1.7-20.6).

CONCLUSION

The high incidence of TB among contacts who did not meet the Brazilian criteria for LTBI treatment strongly suggests that these criteria should be reviewed. Furthermore, even among BCG-vaccinated contacts, TST induration>or=5 mm was the only variable that predicted the development of TB disease within 2years.

Idiopathic giant-cell granulomatous hypophysitis mimicking acute meningitis

A 32-year-old woman presented with severe headache, photophobia, fever, nausea, vomiting, and worsening vision. She had also noted several months of amenorrhea. She was febrile to 38.9 degrees C. Laboratory evaluation revealed a markedly elevated erythrocyte sedimentation rate. Lumbar puncture revealed a cerebrospinal fluid lymphocytic pleocytosis and an elevated protein level. Endocrine studies revealed evidence of panhypopituitarism without diabetes insipidus. A magnetic resonance imaging study showed a 2-cm pituitary mass with optic chiasmal compression. The patient had a trans-sphenoidal resection of the mass. Pathology revealed multinucleated giant cells in necrotic debris, but no evidence of pituitary tumor. Studies looking for evidence of systemic granulomatous disease were negative. The patient was considered to have idiopathic giant-cell granulomatous hypophysitis. After surgery, the patient's vision improved and hormone replacement therapy was initiated. This case illustrates that idiopathic giant-cell granulomatous hypophysitis should be considered in the differential diagnosis of a patient presenting with a pituitary mass, hypopituitarism, and meningitis-like symptoms.

Human infection by Brucella melitensis: an outbreak attributed to contact with infected goats

Although several outbreaks of Brucella melitensis infection have been reported among laboratory workers or goat cheese consumers, outbreaks related to rural labour have been rarely studied. An outbreak of human brucellosis among farm workers of Argentina was studied and revealed a close relationship with an epidemic of caprine abortions which occurred shortly before on the same farm. High rates of B. melitensis infection were found among goats. Active brucellosis was diagnosed in 33 subjects (14 with positive blood culture for B. melitensis), while other 27 did not show evidence of illness. While 25 of the brucellosis active patients were rural workers, only 5 of the healthy subjects were engaged in rural labour. Active brucellosis was diagnosed in 91.3% of the subjects in continuous contact with goats and in 32% of those having an occasional contact with the animals. All the 60 subjects denied consumption of goat cheese or milk. As shown here, epidemic human infections by B. melitensis may develop among people frequently in contact with infected goat herds or goat manure.