Diagnostic Testing Accuracy for Helicobacter pylori Infection among Adult Patients with Dyspepsia in Cuba's Primary Care Setting.

Evidence of the effectiveness of the tests used to diagnose Helicobacter pylori (H. pylori) in primary healthcare is limited. This cross-sectional study aims to assess the accuracy of tests used for to diagnose H. pylori infection in primary care patients and its relationship with gastroduodenal pathologies. Over 12 months, 173 primary care patients with dyspeptic symptoms were referred for upper gastrointestinal endoscopy to obtain gastric biopsies, and venous blood was extracted from them. H. pylori infection was detected using a rapid urease test (RUT), real-time polymerase chain reaction (RT-PCR), H. pylori-IgG ELISA, and Western blot (WB). The culture and histological findings were used as the reference standard for H. pylori infection. H. pylori prevalence was 50%. There were no significant differences between men and women overall or by age group. The presence of H. pylori was associated with chronic moderate gastritis and its absence with chronic inactive gastritis, as well as the combination of gastritis and gastric lesions (p < 0.05). RUT and ELISA H. pylori -IgG tests showed the highest overall performance (accuracy 98.9% and 84.4%), followed by WB and RT-PCR (accuracy 79.3% and 73.9%). These findings support the notion that combined invasive and noninvasive methods, such as RUT and H. pylori-IgG ELISA, can be a primary diagnostic screening tool for detecting H. pylori among adult dyspeptic patients in Cuba's primary care setting.

Prevalence of Helicobacter pylori vacA, cagA, and iceA Genotypes in Cuban Patients with Upper Gastrointestinal Diseases.

Virulence factors of Helicobacter pylori can predict the development of different gastroduodenal diseases. There are scarce reports in Cuba about H. pylori isolates genotyping. The aim of the present investigation was to identify allelic variation of the virulence genes vacA, cagA, and iceA in sixty-eight patients diagnosed as H. pylori positive by culture. In seven out of 68 patients, strains from both gastric regions were obtained and considered independent. DNA was extracted from all the H. pylori strains and evaluated by PCR-genotyping. The vacA s1 allele, cagA gene, and iceA2 allele were the most prevalent (72.0%, 56.0%, and 57.3%, respectively). Alleles from m-region showed a similar frequency as s1a and s1b subtypes. The presence of multiple H. pylori genotypes in a single biopsy and two gastric region specimens were found. Significant statistical association was observed between iceA2 allele and patients with non-peptic ulcer dyspepsia (NUD) (P = 0.037) as well as virulence genotypes (s1, s1m2) and patients over 40 years old (P < 0.05). In conclusion, the results demonstrated a high prevalence of H. pylori virulent genotypes in Cuban patients over 40 years old while iceA2 alleles demonstrated a good specificity in patients with NUD.

Low prevalence of Helicobacter pylori among symptomatic children from a hospital in Havana, Cuba.

The aims of this study were to assess the prevalence of Helicobacter pylori infection and to introduce a new algorithm to improve its diagnosis in Cuban symptomatic children. One hundred and thirty-three consecutive children with upper gastrointestinal symptoms were studied. Patients were endoscoped and antral biopsies were obtained for rapid urease test (RUT), culture and histology. Prevalence of H. pylori infection was 30.8%. No statistical differences were found concerning demographic, socio-economic factors or chief clinical complaints, between H. pylori-positive and negative children, except for haematemesis, which was significantly higher in infected children (p = 0.003). Histologically, there was statistical association between moderate chronic gastritis in infected children (p = 0.04). Culture and RUT had the highest specificity and sensitivity, respectively. The prevalence of H. pylori infection in Cuban symptomatic children is similar to the one observed in developed countries. Culture and RUT is a useful combination to diagnose H. pylori infection in paediatric patients.

Phenotypic and genetic characterization of antimicrobial profiles of Helicobacter pylori strains in Cuba.

The study evaluated the antibiotic resistance patterns of Helicobacter pylori strains against metronidazole and clarithromycin in a hospital in Havana, Cuba. Eighty-five percent, 22.5%, and 10% of 40 H. pylori strains investigated were resistant to metronidazole, ciprofloxacin, and clarithromycin respectively but all were susceptible to amoxicillin and tetracycline. RdxA truncation was found only in metronidazole-resistant strains. In such strains, reported are eight and two novel mutations in the rdxA and frxA genes respectively. Two-point mutations in the 23S rRNA genes of clarithromycin-resistant strains were detected. A high prevalence of metronidazole resistance was found in Cuban H. pylori strains. Mutations in the rdxA gene may contribute more significantly than frxA gene to the high level of resistance to metronidazole. This study supports the need to continue monitoring the antibiotic susceptibility in H. pylori in Cuba to guide the treatment of such infection.

Evaluation of the BIOCEN GC agar medium base in antimicrobial susceptibility testing of Neisseria gonorrhoeae.

BACKGROUND: Since 1995, the Cuban Reference Laboratory for Neisseria has been monitoring the antibiotic susceptibility of gonococci, following the methodology of the National Committee for Clinical Laboratory Standards, which uses GC agar medium base supplemented with 1% Vitox. We evaluated three lots of GC agar medium base produced by BIOCEN, Cuba, in antibiotic susceptibility testing of reference and wild strains of gonococci. METHODS: The susceptibilities to five antibiotics were evaluated five times on three lots of GC agar medium base from BIOCEN. Four and one gonococcal reference strains were tested by MIC dilution and disc diffusion methods, respectively. Later, the antimicrobial susceptibilities of ten wild Neisseria gonorrhoeae strains were tested in triplicate. As internal control, a GC agar medium from Difco was used. RESULTS: All antibiotic MICs obtained on four lots of GC agar medium from different manufacturers fell within the proposed quality control limits for reference strains analyzed. The disc diffusion data for the reference strain of N. gonorrhoeae ATCC 49226 to five antibiotics provided essentially identical results in all lots of GC agar medium base. For wild strains of gonococci, identical modal MIC values and zone size diameters within a 3-mm range were observed in all the antibiotics tested. CONCLUSIONS: Excellent agreement in susceptibility testing methods among different lots of GC agar medium base from BIOCEN and Difco was obtained for all reference and wild gonococcal strains and antibiotics tested. We proposed that GC medium from BIOCEN can be used in antimicrobial susceptibility testing of N. gonorrhoeae by MIC dilution and disc diffusion tests.

Evaluation of four methods for detecting the beta-lactamase activity in Neisseria gonorrhoeae isolated in Cuba

Four methods (chromogenic, acidimetric, inhibition, and iodometric) for demonstration of the beta-lactamase production by 70 isolates of Neisseria gonorrhoeae, were evaluated in Cuba. There was 100 percent correlation between all beta-lactamase methods and the standardized penicillin dilution susceptibility test for penicillinase-non-producing N. gonorrhoeae. For penicillinase-producing N. gonorrhoeae strains, there was a perfect correlation between the chromogenic method and penicillin susceptibility testing, but one and two strains failed to give a positive result for beta-lactamase with the inhibition/acidimetric and the iodometric methods, respectively. There was a high concordance between the chromogenic method, considered as gold standard and the rest of penicillinase tests evaluated: Kappa Index (KI) = 0.98 for inhibition/acidimetric methods and KI = 0.97 for the iodometric method. The four methods evaluated were accurate, reproducible, easily readable, economical, and ease to use for screening primary isolates of N. gonorrhoeae in Cuba. We recommended the use of the inhibition method, when testing the penicillinase activity in gonococcal isolates in provincial and municipal reference laboratories.

Evaluación de diferentes métodos de utilización de azúcares en Neisseria gonorrhoeae / Evaluation of different methods of utilization of sugars in Neisseria gonorrhoeae

Se evaluaron 5 métodos de utilización de azúcares en 25 cepas identificadas previamente como Neisseria gonorrhoeae: agar CTA, agar CTA modificado, agar gelatina almidón, agar Mueller Hinton más azul de bromotimol y método rápido. Por los métodos de CTA y rápido fueron identificadas 100 por ciento de las cepas de N. gonorrhoeae, mientras que por los métodos de CTA modificado y agar gelatina almidón fue 96 por ciento. Ninguna cepa de gonococo fue identificada por el método de agar Mueller Hinton más azul de bromotimol. El medio de agar cistina tripticasa (CTA), constituye el método de elección para confirmar los aislamientos de Neisseria gonorrhoeae; es elaborado fundamentalmente por compañías norteamericanas, por lo que su adquisición en Cuba resulta difícil. Los métodos de agar gelatina almidón y rápido constituyen alternativas útiles del medio CTA, por lo que su uso se propone en este trabajo

Evaluación de diferentes métodos de utilización de azúcares en Neisseria gonorrhoeae / Evaluation of different methods of utilization of sugars in Neisseria gonorrhoeae

Se evaluaron 5 métodos de utilización de azúcares en 25 cepas identificadas previamente como Neisseria gonorrhoeae: agar CTA, agar CTA modificado, agar gelatina almidón, agar Mueller Hinton más azul de bromotimol y método rápido. Por los métodos de CTA y rápido fueron identificadas 100 por ciento de las cepas de N. gonorrhoeae, mientras que por los métodos de CTA modificado y agar gelatina almidón fue 96 por ciento. Ninguna cepa de gonococo fue identificada por el método de agar Mueller Hinton más azul de bromotimol. El medio de agar cistina tripticasa (CTA), constituye el método de elección para confirmar los aislamientos de Neisseria gonorrhoeae; es elaborado fundamentalmente por compañías norteamericanas, por lo que su adquisición en Cuba resulta difícil. Los métodos de agar gelatina almidón y rápido constituyen alternativas útiles del medio CTA, por lo que su uso se propone en este trabajo(AU)

Resultados y experiencias de la vigilancia nacionalde meningitis bacteriana en Cuba / Resultados y experiencias de la vigilancia nacional

Objetivos: Desde 1998 se implementó en Cuba un nuevo sistema de vigilancia nacional de meningitis bacteriana (VNMB) con el objetivo de lograr información en correspondencia con el desarrollo científico actual y las exigencias del programa nacional de prevención y control de estas infecciones. Resultados: Este sistema permitió medir el impacto de la vacuna contra H. influenzae tipo b (Hib) en 1999 sin necesidad de un proyecto y gastos adicionales, demostrando la reducción inmediata de la incidencia (52por ciento). Hasta el 2002 fueron reportados 82 niños < 5 años de los cuales 61(74,4por ciento) no estaban vacunados. Entre los vacunados hubo 14 (66,7por ciento) con una sola dosis aplicada.A partir de esta intervención S. pneumoniae resultó el principal agente causal de meningitis. Los serogrupos/ serotipos más frecuentes han sido 19, 6, 14, 18, 1, 7 y 23, mostrando un 40por ciento de susceptibilidad disminuida a la penicilina. Por primera vez identificamos: - fuerte asociación (RR > 20) de los estudiantes internos de primaria con la enfermedad, - incidencia elevada entre amas de casa (> 2/100 000) y jubilados (> 8/100 000), - fuerte asociación (Razón de disparidad > 20) de la muerte con jubilados y amas de casa en el análisis multivariado. Los resultados microbiológicos posibilitaron la caracterización de agentes y la política antibiótica más adecuada. La letalidad general de la meningitis neumocócica fue > 32 por ciento y fundamentalmente en ancianos. Conclusiones: LaVNMB aportó novedosa información clínico - epidemiológica y microbiológica, permitiendo ampliar el marco integral de los conocimientos y garantizando acciones más efectivas y eficientes en un proyecto multidisciplinario e intersectorial generalizado (AU)

[Evaluation of different methods of utilization of sugars in Neisseria gonorrhoeae]. / Evaluación de diferentes métodos de utilización de azúcares en Neisseria gonorrhoeae.

5 methods of utilization of sugars were evaluated in 25 strains previously identified as N. gonorrhoeae: CTA agar, modified CTA agar, gelatin starch agar, Mueller Hinton agar plus bromotimol blue and rapid method. 100% of the strains of N. gonorrhoeae were identified by the CTA and rapid methods, whereas 96% were identified by the modified CTA and gelatin starch agar methods. No strain of gonoccocus was identified by the Mueller Hinton agar method plus bromotimol blue. The cystine tripticase agar medium (CTA) is the elective method to confirm the isolates of Neisseria gonorrhoeae. As it is mainly made by U.S. companies, it is difficult for Cuba to acquire it. The gelatin-starch agar method and the rapid method are useful alternative of the CTA medium, so their use is proposed in this paper.

Evaluation of four methods for detecting the beta-lactamase activity in Neisseria gonorrhoeae isolated in Cuba.

Four methods (chromogenic, acidimetric, inhibition, and iodometric) for demonstration of the beta-lactamase production by 70 isolates of Neisseria gonorrhoeae, were evaluated in Cuba. There was 100% correlation between all beta-lactamase methods and the standardized penicillin dilution susceptibility test for penicillinase-non-producing N. gonorrhoeae. For penicillinase-producing N. gonorrhoeae strains, there was a perfect correlation between the chromogenic method and penicillin susceptibility testing, but one and two strains failed to give a positive result for beta-lactamase with the inhibition/acidimetric and the iodometric methods, respectively. There was a high concordance between the chromogenic method, considered as gold standard and the rest of penicillinase tests evaluated: Kappa Index (KI) = 0.98 for inhibition/acidimetric methods and KI = 0.97 for the iodometric method. The four methods evaluated were accurate, reproducible, easily readable, economical, and ease to use for screening primary isolates of N. gonorrhoeae in Cuba. We recommended the use of the inhibition method, when testing the penicillinase activity in gonococcal isolates in provincial and municipal reference laboratories.

Typing and susceptibility to penicillin of Neisseria meningitidis isolated from patients in Cuba (1993-1999)

The susceptibility to penicillin of 111 Neisseria meningitidis strains was assessed by the agar-dilution procedure and serosubtypes were determined by a whole-cell enzyme-linked immunoassay using monoclonal antibodies reagents. Thirty-five isolates showed reduced sensitivity to penicillin (MIC > or = 0.1 mg/l and <= 1 mg/l) and no resistant strains were detected. The most common phenotype was B:4:P1.15 (77.5 percent) and a rising trend of non-typeable and non-subtypeable strains was detected. The increase in levels of minimal inhibitory concentrations of meningococci to penicillin gives cause for concern and the increase in non-typeable and non-subtypeable isolation demand the use of molecular biology techniques for their typing