Risks of low vaccination coverage and strategies to prevent the resurgence of vaccine-preventable diseases in infants in the COVID-19 pandemic scenario: recommendations for Latin America and the Caribbean by the group of experts on infant immunization for Latin America.

INTRODUCTION: The WHO 2030 Immunization Agenda (IA-2030) harmonizes immunization activity plans at community, national, regional and global levels. Additionally, medical societies play an important role. The Latin American Group of Experts on Infant Immunization, established in 2018, advises on the harmonization, update, and optimization of infant vaccination programs in Latin America and the Caribbean (LAC). In September 2021, 41 such experts from 13 LAC countries met to develop recommendations for increasing regional vaccination coverage to avoid the reemergence of vaccine-preventable diseases and/or the occurrence of outbreaks. AREAS COVERED: The following items were evaluated: (i) immunization challenges before and during the COVID-19 pandemic; (ii) the status of current immunization programs, particularly infant pertussis and polio vaccination; (iii) possible solutions for overcoming vaccination challenges and achieving regional vaccination coverage targets. EXPERT OPINION/COMMENTARY: Medical societies provide valuable recommendations to guide and update vaccination schedules. In the LAC region, possible strategies to achieve target vaccination rates include the use of combination vaccines, strengthening surveillance systems, improving school attendance, advancing vaccine education and confidence, striving for vaccination equity, widening operational capacity, creating strategic alliances, and strengthening the role of medical groups. It is hoped that these recommendations will be implemented in the LAC region.

[QacEdelta1 gene frequency and biocide resistance in extended-spectrum beta-lactamase producing enterobacteriaceae clinical isolates]. / Frecuencia del gen qacEal y resistencia a biocidas en aislamientos clínicos de enterobacterias productoras de betalactamasas de espectro extendido.

OBJECTIVE: To determine the frequency of the gene qacEdelta1 and characterize the resistance to biocides of extended-spectrum beta-lactamases producing enterobacteriaceae (ESBL-PE) obtained from clinical isolates causing nosocomial infections. MATERIAL AND METHODS: In total 59 ESBL-PE causing nosocomial infections were included: Klebsiella pneumoniae (35) and Enterobacter cloacae (24). Minimal inhibitory concentration (MIC) was tested for chlorhexidine (CHX) and benzalkonium chloride (CLBZ) by agar dilution technique. Amplification of the SHV, TLA-1 and qacEdelta1 genes were performed by PCR using specific primers and plasmid identification was done by alkaline lysis method. Matting experiments were obtained on solid agar method. RESULTS: Chlorhexidine-resistance was found in 100% of the ESBL-PE and benzalkonium chloride-resistance in 80%. In 68% of the biocides-resistant strains the qacEdelta1 gene was present. The 66% of resulting transconjugants were resistant to CHX and the gene qacEdelta1 was detected in 55%. CONCLUSIONS: The qacEdelta1 gene of antiseptic resistance is widespread in the EP-ESBL and can be transferred horizontally. Thus it is advisable to use combinations of antiseptics, as recommended in the literature, to avoid selection of multiresistant bacteria in hospitals, causing nosocomial infections.

Audiologic and vestibular findings in a sample of human immunodeficiency virus type-1-infected Mexican children under highly active antiretroviral therapy.

OBJECTIVE: There is little information about audiologic and vestibular disorders in pediatric patients infected with the Human Immunodeficiency Virus type-1 (HIV-1). The aim of this study was to evaluate audiologic and vestibular disorders in a sample of HIV-1-infected children receiving Highly Active Antiretroviral Therapy. METHODS: Patients underwent pure tone audiometry, speech discrimination testing, auditory brainstem responses, electronystagmography, and rotatory testing. HIV-1 viral load and absolute CD4+ cell counts were registered. RESULTS: Twenty-three patients were included, aged 4.5 years (median, range 5 months to 16 years). Pure tone audiometry was carried out in 12 children over 4 years of age: 4 (33%) showed hearing loss, 2 were conductive. Auditory brainstem responses were measured in all 23 patients, suggesting conductive hearing loss in 6 and sensorineural hearing loss in 2. Most patients with conductive hearing loss had the antecedent of acute or chronic suppurative otitis media but with dry ears at the time of evaluation (p=0.003). Abnormal prolongations of interwave intervals in auditory brainstem responses were observed in 3 children (13%, 4 ears), an abnormal morphology in different components of auditory brainstem responses in 4 (17.4%, 7 ears), and abnormal amplitude patterns in 11 patients (48%, 17 ears). Vestibular tests were abnormal in all six patients tested, with asymmetries in caloric and rotatory tests. Although differences were not significant, in general, audiologic abnormalities were more frequent in patients with more prolonged HIV-1 infections, higher viral loads, or lower absolute CD4+ cell counts. CONCLUSIONS: Conductive hearing loss associated with previous otitis media events, abnormalities in auditory brainstem responses suggesting disorders at different levels of the auditory pathways, and unilateral vestibular hyporeflexia were frequent findings in our sample of HIV-1-infected children under Highly Active Antiretroviral Therapy. These findings suggest that HIV-1-infected children should be submitted to audiologic and vestibular evaluation as early as possible in order to reduce their impact on the psychosocial development of these patients.

Lyme Neuroborreliosis is a Severe and Frequent Neurological Disease in Mexico.

OBJECTIVE: To describe clinical cases with neurological manifestations associated with Borrelia burgdorferi infection in a large cohort of children and adults from Mexico. MATERIAL AND METHODS: Patients with neurological manifestation (cranial neuritis, radiculoneuritis, meningitis and encephalomyelitis) were recruited in one pediatric and two general hospitals, during January 2006-December 2015. Blood and cerebrospinal fluid (CSF) samples were drawn from each patient at inclusion. IgM and IgG antibodies against B. burgdorferi were detected using a commercial ELISA test, and confirmed by Western-Blot test (WB) using three different antigens from Borrelia burgdorferi complex. Following CDC criteria were considered true cases with both positive tests. RESULTS: Of 606 patients recruited, 403 (66.5%) were adults and 203 (33.4%) children, 50.5% were male. B. burgdorferi infection was diagnosed in 168 patients (27.7%), 97 adults, mean age 42 ± 14.7 years and 71 children, mean age 9.6 ± 5 years; early disseminated disease occurred in 130 cases (77.4 %) and chronic stage in 38 (22.6 %). A previous tick bite was reported by 21% cases, and 5% recalled an erythema migrans lesion. Polyradiculoneuropathy and encephalomyelitis were the most common manifestations, whereas 14.8% presented an initial Guillain-Barré Syndrome. B. burgdorferi sensu stricto was identified in 142 (84%) cases, B. garinii in 14 (8%), B. afzelii in three, and nine cases presented coinfection with two species. CONCLUSION: Lyme neuroborreliosis is a frequent condition in patients with neurological diseases in Mexico.

Gram-negative infections in pediatric and neonatal intensive care units of Latin America.

In order to review the epidemiology of Gram-negative infections in the pediatric and neonatal intensive care units (PICUs and NICUs) of Latin America a systematic search of PubMed and targeted search of SciELO was performed to identify relevant articles published since 2005. Independent cohort data indicated that overall infection rates were higher in Latin American PICUs and NICUs versus developed countries (range, 5%-37% vs 6%-15%, respectively). Approximately one third of Latin American patients with an acquired PICU or NICU infection died, and crude mortality was higher among extremely low-birth-weight infants and those with an infection caused by Gram-negative bacteria. In studies reporting > 100 isolates, the frequency of Gram-negative pathogens varied from 31% (Colombia) to 63% (Mexico), with Klebsiella pneumoniae, Pseudomonas aeruginosa, and Escherichia coli the predominant pathogens in almost all countries, and Acinetobacter spp. and Serratia spp. isolated sporadically. The activity of quinolones and third-generation cephalosporins against P. aeruginosa, Acinetobacter spp., and Enterobacteria was seriously compromised, coincident with a high prevalence of circulating extended-spectrum ß-lactamases. Furthermore, we identified two observational studies conducted in Chile and Brazil reporting infections by P. aeruginosa and Acinetobacter baumannii in PICUs, demonstrating resistance to carbapenems, and two outbreaks of carbapenem-resistant K. pneumoniae in Colombia and Brazil. The endemicity of multidrug-resistant Gram-negative infections in Latin American PICUs and NICUs is punctuated by intermittent clonal outbreaks. The problem may be alleviated by ensuring ICUs are less crowded, increasing staffing levels of better-trained health care personnel, and implementing antimicrobial stewardship and surveillance programs.

High-virulence clone of group B streptococci unable to grow at high temperatures is present in serotypes other than type III.

Highly virulent clonotypes of serotype III seem to cause much of the perinatal morbidity and mortality attributed to Streptococcus agalactiae (group B streptococci, GBS), One of these clonal types, designated the "high-virulence clone" (HVC), was identified by its inability to grow at 40 degrees C in a chemically defined medium. In the present study, this inability to grow at high temperatures was used as a marker to identify HVC in a sample of 286 Mexican GBS isolates. Forty-three isolates (15%) were identified as belonging to this clone: 15 were invasive isolates, 33 were serotype III (77%), and 10 were of serotypes other than type III (23%). These results demonstrate that HVC is more prevalent in Mexico than previously reported and that this clone is not restricted to serotype III isolates.

Serotypes of 286 group B streptococci isolated from asymptomatic carriers and invasive disease cases in Mexico.

BACKGROUND: Group B Streptococcus (GBS) remains as a leading cause of neonatal sepsis and meningitis in developed countries, where type III is the most common serotype. Although GBS is considered an uncommon cause of perinatal pathology in Mexico, a vaginal colonization rate of 14% in pregnant women and a neonatal infection rate of 1/1500 live births have been reported. The aim of this study was to determine the serotype distribution in a collection of 286 GBS strains isolated in Mexico from asymptomatic carriers and in adult and neonatal invasive disease cases. METHODS: The collection included GBS strains isolated between January 1988 and April 1998 at the Instituto Nacional de Perinatologia and Hospital de Pediatria in Mexico City. GBS and serotype were confirmed by latex agglutination. RESULTS: Most strains were isolated from asymptomatic carriers (66%). 30% were invasive isolates, and 10% of them were from neonates. 48.6% were type I, 32.9% type III, 14% type II, and 4% were non-typeable. CONCLUSION: Serotype I is predominant in Mexico but participation of serotype III is increasing, and a decrease of non-typeable isolates was detected.

Identification of the high-virulence clone of group B streptococci by using a probe containing a putative aldolase gene.

A high-virulence clone (HVC) was proposed as causing much of the morbidity and mortality when a collection of group B Streptococcus (GBS) isolates was examined by multi-locus enzyme electrophoresis. HVC isolates could be further distinguished by their inability to grow at 40 degrees C, and a temperature-sensitive aldolase was identified as responsible for this characteristic. In the present study, the HVC was sought in a collection of 57 GBS isolates by hybridization with a probe containing a putative aldolase gene on genomic DNA restriction enzyme digests. Isolates were initially classified as HVC or non-HVC by their inability to grow at 40 degrees C. Three serotype III invasive isolates had the HVC control restriction/hybridization pattern. They were also unable to grow at 40 degrees C. The remaining 11 invasive and all carrier isolates showed a pattern identical to that of the non-HVC control. These results provide additional support for the existence of a highly virulent clonal group among serotype III isolates and suggest that hybridization with a probe containing the aldolase gene on DNA restriction enzyme digests can be an alternative method for identifying highly virulent isolates.

Response to two consecutive protease inhibitor combination therapy regimens in a cohort of HIV-1-infected children.

The response to 2 consecutive protease inhibitor (P1) combination regimens was evaluated in a cohort of HIV-1-infected children. Twelve children, most of whom had been heavily treated, received a 3-drug treatment: saquinavir in hard gelatin capsules (SQVhgc) + zidovudine (ZDV) + didanosine. When this treatment failed it was replaced by a 4-drug regimen: ritonavir + SQVhgc + ZDV + lamivudine. A mild and temporary decrease in viral load (VL) was observed with the initial regimen (p = 0.22). Therapy failure occurred in 7 patients (58%) within 9 months and in another 3 (25%) within 9-18 months. The 7 children who failed within 9 months received the subsequent boosted regimen, leading to a significant and lasting reduction in VL (p = 0.001). None of the patients failed on the boosted regimen: 5/7 achieved a VL of < 400 copies/ml and 3/7 achieved a VL of < 50 copies/ml. Our results suggest that a 4-drug regimen including 2 PIs produces a better and more sustained response than a 3-drug regimen including only 1 PI, and that a good, sustained response is possible with subsequent boosted regimens even in heavily treated children.

Clonal and horizontal dissemination of Klebsiella pneumoniae expressing SHV-5 extended-spectrum beta-lactamase in a Mexican pediatric hospital.

One hundred eighty-four clinical isolates of Klebsiella pneumoniae were recovered from August 1996 to October 1997 at the Pediatric Hospital of the Instituto Mexicano del Seguro Social in Mexico City, Mexico. Most of the isolates were collected from the neonatal intensive care unit and infant wards, which are located on the same floor of the hospital. Isolates were genotypically compared by pulsed-field gel electrophoresis with XbaI restriction of chromosomal DNA. Of 184 clinical isolates, 91 belonged to cluster A and comprised three subtypes (A1, A2, and A3), while 93 isolates, comprising two minor clones, B (10 isolates) and C (7 isolates), and 76 unique patterns, were considered unrelated isolates (URI). Susceptibility patterns were indistinguishable in both groups. Fifty extended-spectrum beta-lactamase-producing isolates, including 34 from clone A and 16 from URI, were examined for further studies. Molecular and genetic analysis showed that 47 of 50 clinical isolates expressed the SHV-5 beta-lactamase. This enzyme, in combination with TEM-1, was encoded in a >or=170-kb conjugative plasmid. Results indicate that dissemination of this resistance was due to clonal and horizontal spread.

Selorogic evidences suggesting the presence of borrelia burgdorferi infection in Mexico

Background. Lyme disease is the most common vector-borne Human disease in Europe and the United States. In Mexico, clinical cases suggestive of lyme borreliosis have been reported; however, infection was not confirmed by serologic or microbiologic tests. Methods. To study the prevalence of IgG antibodies againts Borrelia burgdorferi among Mexican persons, a community-based sero-survery including all states of Mexico was done. A sample of 2,890 sera representing individuals of all ages and all socioeconomic levels was studied. Antibodies ati-B. burgdorferi were determined by enzyme-linked immunosorbent assay (ELISA) using a whole-cell sonicated extract of B. burgdorferi strain B31. Serum specimens positive for ELISA were further studied by Western blot (WB). A serum sample was considered positive by WB if at least three of the following protein bands were recognized: 18, 24, 28, 31, 34, 39, 41, 45, 58, 62, 66, and 93 KDa. Some WB positive specimens were futher confirmed with an inmmunodot-blot (IDB) test using recombinant and purified B. burgdorferi proteins. Results. Of the 2,890 specimens, 34 were positive for ELISA; nine of these 34 were confirmed as positive by WB. Four of the nine WB positive sera were testd by IDB and all four were positive. The prevalence of WB confirmed cases in the sample studied was 0.3 percent. Positive specimens were from residents of the northeastern and central areas of Mexico. Conclusions. the resological evidences of this study suggest that Borrelia burgdorferi infection is present in the Mexican population. This finding should be confirmed by documenting the infection in clinical cases and in tick vectors