Multidrug-Resistant Staphylococcus sp. and Enterococcus sp. in Municipal and Hospital Wastewater: A Longitudinal Study.

The objective of the study was to detect multidrug-resistant Staphylococcus sp. and Enterococcus sp. isolates in municipal and hospital wastewater and to determine their elimination or persistence after wastewater treatment. Between August 2021 and September 2022, raw and treated wastewater samples were collected at two hospital and two community wastewater treatment plants (WWTPs). In each season of the year, two treated and two raw wastewater samples were collected in duplicate at each of the WWTPs studied. Screening and presumptive identification of staphylococci and enterococci was performed using chromoagars, and identification was performed with the Matrix Assisted Laser Desorption Ionization Time of Flight mass spectrometry (MALDI-TOF MS®). Antimicrobial susceptibility was performed using VITEK 2® automated system. There were 56 wastewater samples obtained during the study period. A total of 182 Staphylococcus sp. and 248 Enterococcus sp. were identified. The highest frequency of Staphylococcus sp. isolation was in spring and summer (n = 129, 70.8%), and for Enterococcus sp. it was in autumn and winter (n = 143, 57.7%). Sixteen isolates of Staphylococcus sp. and sixty-three of Enterococcus sp. persisted during WWTP treatments. Thirteen species of staphylococci and seven species of enterococci were identified. Thirty-one isolates of Staphylococcus sp. and ninety-four of Enterococcus sp. were multidrug-resistant. Resistance to vancomycin (1.1%), linezolid (2.7%), and daptomycin (8.2%/10.9%%), and a lower susceptibility to tigecycline (2.7%), was observed. This study evidences the presence of Staphylococcus sp. and Enterococcus sp. resistant to antibiotics of last choice of clinical treatment, in community and hospital wastewater and their ability to survive WWTP treatment systems.

Antimicrobial resistance: One Health approach.

In this research, a review of antimicrobial resistance (AMR) is conducted as part of the One Health approach. A review of publications, which included "antimicrobial resistance" and "One Health," was conducted. Among the global health problems, AMR is the one that most clearly illustrates the One Health approach. AMR is a critical global problem affecting humans, the environment, and animals. This is related to each of these three components due to the irresponsible and excessive use of antimicrobials in various sectors (agriculture, livestock, and human medicine). Improper management of antimicrobials, inadequate control of infections, agricultural debris, pollutants in the environment, and migration of people and animals infected with resistant bacteria facilitate the spread of resistance. The study aimed to analyze the problem of AMR from a health perspective to analyze the different actors involved in One Health.

Antimicrobial Resistance Patterns and Clonal Distribution of E. coli, Enterobacter spp. and Acinetobacter spp. Strains Isolated from Two Hospital Wastewater Plants.

The objective of this study was to determine the presence and persistence of antimicrobial-resistant enterobacteria and their clonal distribution in hospital wastewater. A descriptive cross-sectional study was carried out in wastewater from two Mexico City tertiary level hospitals. In February and March of 2020, eight wastewater samples were collected and 26 isolates of enterobacteria were recovered, 19 (73.1%) isolates were identified as E. coli, 5 (19.2%) as Acinetobacter spp. and 2 (7.7%) as Enterobacter spp. Antimicrobial susceptibility profiles were performed using the VITEK 2® automated system and bacterial identification was performed by the Matrix-Assisted Laser Desorption/Ionization-Time of Flight mass spectrometry (MALDI-TOF MS®). ESBL genes were detected by polymerase chain reaction (PCR) and clonal distributions of isolates were determined by pulsed-field gel electrophoresis (PFGE). E. coli susceptibility to different classes of antimicrobials was analyzed and resistance was mainly detected as ESBLs and fluoroquinolones. One E. coli strain was resistant to doripenem, ertapenem, imipenem and meropenem. The analysis by PCR showed the presence of specific ß-lactamases resistance genes (blaKPC, blaCTX-M). The PFGE separated the E. coli isolates into 19 different patterns (A-R). PFGE results of Acinetobacter spp. showed the presence of a majority clone A. Surveillance of antimicrobial resistance through hospital wastewater is an important tool for early detection of clonal clusters of clinically important bacteria with potential for dissemination.

Surveillance of Antimicrobial Resistance in Hospital Wastewater: Identification of Carbapenemase-Producing Klebsiella spp.

The objective of this study was to investigate the presence and persistence of carbapenemase-producing Klebsiella spp. isolated from wastewater and treated wastewater from two tertiary hospitals in Mexico. We conducted a descriptive cross-sectional study in two hospital wastewater treatment plants, which were sampled in February 2020. We obtained 30 Klebsiella spp. isolates. Bacterial identification was carried out by the Matrix-Assisted Laser Desorption/Ionization-Time of Flight mass spectrometry (MALDI-TOF MS®) and antimicrobial susceptibility profiles were performed using the VITEK2® automated system. The presence of carbapenem resistance genes (CRGs) in Klebsiella spp. isolates was confirmed by PCR. Molecular typing was determined by pulsed-field gel electrophoresis (PFGE). High rates of Klebsiella spp. resistance to cephalosporins and carbapenems (80%) were observed in isolates from treated wastewater from both hospitals. The molecular screening by PCR showed the presence of blaKPC and blaOXA-48-like genes. The PFGE pattern separated the Klebsiella isolates into 19 patterns (A-R) with three subtypes (C1, D1, and I1). Microbiological surveillance and identification of resistance genes of clinically important pathogens in hospital wastewater can be a general screening method for early determination of under-detected antimicrobial resistance profiles in hospitals and early warning of outbreaks and difficult-to-treat infections.

Detection of capsular genotypes of methicillin-resistant Staphylococcus aureus and clonal distribution of the cap5 and cap8 genes in clinical isolates.

Up until now, the capsular polysaccharides of Staphylococcus aureus have been classified into 11 types, of which only 2 types 5 and 8; (encoded by the genes cap5 and cap8, respectively) are present in 80-90% of clinically significant strains. The aim of the present study was to detect the capsular genotypes of methicillin-resistant S. aureus (MRSA) clinical isolates and determined their clonal distribution. A total of 262 MRSA clinical isolates from different hospitals in Mexico were analyzed by PCR to determine the genetic characteristics of their capsule expression. Pulsed-field gel electrophoresis and multilocus sequence typing were used to characterize the isolates. The analysis of the capsular genotypes among MRSA isolates showed that 245 isolates (93.5%) contained the cap5 gene, and that the remaining 17 (6.5%) encoded the cap8 gene. The MRSA isolates were grouped into four clonal groups. The identification of the capsular genotypes of clinical isolates of MRSA is important information because potential vaccine formulations against S. aureus involve capsular polysaccharides.

High exposure to pathogenic leptospires by the population residing in dairy farms in Hidalgo, Mexico.

Leptospirosis is a neglected zoonotic disease of unknown magnitude that has been overlooked and underreported, influenced by complex interactions established among humans, animals, and the environment; certain occupations, such as working with livestock, have an increased risk of exposure. We conducted a cross trans-sectional study in 374 serum samples obtained from workers and residents of dairy farms in the Tizayuca Basin, Hidalgo, Mexico, to determine the prevalence of anti-Leptospira antibody and the risk factors associated to this type of environment. The determination of anti-Leptospira antibodies was obtained by microscopic agglutination test. Seropositivity was defined from titles > 1:100. Seropositivity of anti-Leptospira antibodies among the population was 46.8% (176/374) (95% Cl 41.9-52.1). Thirty-nine percent (146/74) of the analyzed serum reacted to the Hardjo serovar (Sejröe serogroup). Eighty-eight percent (8/9) slaughterhouse workers tested were seropositive. Those who belonged to an ethnic group had OR 1.78 (IC 1.02-3.11, P = 0.041). Seropositivity was associated with having a secondary school level or lower, with OR 1.79 (IC 0.97-3.29, P = 0.058). Exposure to Leptospira in a dairy production farm is a risk factor for humans. Our findings can contribute to strengthening the intervention of the Public Health System to prevent this zoonosis that prevails in dairy farm environments.

Tracking methicillin-resistant Staphylococcus aureus clones in a hospital in Southern Mexico.

OBJECTIVE: To describe the clinical and molecular characteristics of methicillin-resistant Staphylococcus aureus (MRSA) strains that were collected in the Hospital Regional de Alta Especialidad de Veracruz (HRV). MATERIALS AND METHODS: A total of 107 MRSA strains from individual patients were examined. The strains were collected between September 2009 and September 2010. The clinical and demographic characteristics of patients were analyzed; molecular typing by pulsed-field gel electrophoresis (PFGE), staphylococcal chromosomal cassette mec (SCCmec) typing and multilocus sequence typing were used to characterize the isolates. RESULTS: Two PFGE patterns (NY/J and IB) were identified with 4 and 3 subtypes respectively. The isolates analyzed showed two SCCmec types (I and II) and two sequence types (ST): ST247 and ST5 related with the Iberian and New York/Japan clones respectively. CONCLUSIONS: This study establishes the presence of two very important clonal lineages of MRSA: New York/Japan and Iberian clone in the hospital environment.

OBJETIVO: Describir las características clínicas y moleculares de cepas de Staphylococcus aureus resistentes a meticilina (SARM) que fueron recolectadas en el Hospital Regional de Alta Especialidad de Veracruz (HRV). MATERIAL Y MÉTODOS: Un total de 107 cepas de SARM fueron analizadas en el presente estudio. Las cepas estudiadas fueron recolectadas de septiembre de 2009 a septiembre de 2010. Las características clínicas y demográficas de los pacientes fueron analizadas; la tipificación molecular de las cepas se hizo por electroforesis en campos pulsados, casete cromosomal estafilococócico (SCCmec, en inglés) y secuenciación de múltiples locus. RESULTADOS: Dos patrones electroforéticos (NY/J y IB) fueron identificados con 4 y 3 subtipos respectivamente. Los aislamientos analizados mostraron dos tipos de SCCmec (I y II) y dos secuencias tipo (ST): ST247 y ST5 relacionados con las clonas Ibérica y Nueva York/Japón respectivamente. CONCLUSIONES: . Este estudio estableció la presencia en el medio hospitalario de dos linajes clonales de SARM importantes: Nueva York/Japón e Ibérico.

Tracking methicillin-resistant Staphylococcus aureus clones in a hospital in Southern Mexico / Seguimiento de clonas de Staphylococcus aureus resistentes a meticilina en un hospital en el sur de México

Abstract: Objective: To describe the clinical and molecular characteristics of methicillin-resistantStaphylococcus aureus(MRSA) strains that were collected in theHospital Regional de Alta Especialidad de Veracruz(HRV). Materials and methods: A total of 107 MRSA strains from individual patients were examined. The strains were collected between September 2009 and September 2010. The clinical and demographic characteristics of patients were analyzed; molecular typing by pulsed-field gel electrophoresis (PFGE), staphylococcal chromosomal cassette mec (SCCmec) typing and multilocus sequence typing were used to characterize the isolates. Results: Two PFGE patterns (NY/J and IB) were identified with 4 and 3 subtypes respectively. The isolates analyzed showed two SCCmec types (I and II) and two sequence types (ST): ST247 and ST5 related with the Iberian and New York/Japan clones respectively. Conclusion: This study establishes the presence of two very important clonal lineages of MRSA: New York/Japan and Iberian clone in the hospital environment.

Resumen: Objetivo: Describir las características clínicas y moleculares de cepas deStaphylococcus aureusresistentes a meticilina (SARM) que fueron recolectadas en el Hospital Regional de Alta Especialidad de Veracruz (HRV). Material y métodos: Un total de 107 cepas de SARM fueron analizadas en el presente estudio. Las cepas estudiadas fueron recolectadas de septiembre de 2009 a septiembre de 2010. Las características clínicas y demográficas de los pacientes fueron analizadas; la tipificación molecular de las cepas se hizo por electroforesis en campos pulsados, casete cromosomal estafilococócico (SCCmec, en inglés) y secuenciación de múltiples locus. Resultados: Dos patrones electroforéticos (NY/J y IB) fueron identificados con 4 y 3 subtipos respectivamente. Los aislamientos analizados mostraron dos tipos de SCCmec (I y II) y dos secuencias tipo (ST): ST247 y ST5 relacionados con las clonas Ibérica y Nueva York/Japón respectivamente. Conclusión: Este estudio estableció la presencia en el medio hospitalario de dos linajes clonales de SARM importantes: Nueva York/Japón e Ibérico.

Streptococcus pneumoniae Serotype 3 in Mexico (1994 to 2017): Decrease of the Unusual Clonal Complex 4909 Lineage following PCV13 Introduction.

Streptococcus pneumoniae expressing serotype 3 has a high virulence and a high case fatality ratio. Most studies of serotype 3 pneumococci have focused on a single lineage, the widespread sequence type 180 (ST180). To evaluate the serotype 3 lineages causing infections in Mexico, we characterized 196 isolates recovered from 1994 to 2017. The isolates were mostly susceptible to all antimicrobials tested. A single meningitis isolate was resistant to penicillin, and the resistance to erythromycin was 5.2%. The isolates represented the widely disseminated clonal complex 180 (CC180; n = 140), the unusual CC4909 (n = 42), CC260 (n = 11), and a few singletons (n = 3). CC260 was less frequent among pneumococcal invasive disease isolates than CC180 and CC4909 (P = 0.015). There was a decrease of CC4909 (P < 0.001) following PCV13 introduction (2012 to 2017). The CC4909 isolates were represented mostly by ST1119 (n = 40), seemingly having a restricted geographic origin, with isolates in the PubMLST database having been recovered only in Mexico, the United States, and Germany. A genomic analysis of publicly available genomes showed that ST1119 isolates have less than 32% similarity with ST180 isolates, indicating that these lineages are more separated than revealed by traditional multilocus sequence typing. Considering the suggestions of a lower efficacy of the 13-valent pneumococcal conjugate vaccine against serotype 3, the different dynamics of the two major serotype 3 lineages in Mexico following the introduction of PCV13 should be closely monitored.

Streptococcus pneumoniae: distribution of serotypes and antimicrobial susceptibility in patients with cancer.

OBJECTIVE: To describe the distribution of pneumococcal serotypes causing infectious diseases in patients with hematological malignancies and solid tumors and their antimicrobial susceptibility before and after introduction of pneumococcal conjugate vaccine (PCV7) in Mexico. MATERIALS AND METHODS: Consecutive pneumococcal isolates from hospitalized patients from the SIREVA-network were serotyped using the Quellung reaction and antimicrobial susceptibility was performed using the broth microdilution method. RESULTS: A total of 175 pneumococcal isolates were recovered, 105 from patients with hematological malignancies and 70 with solid tumors. Serotypes 19A (22.7%), 19F (20.4%), and 35B (17.7%) were the most frequent isolates in the first group and serotypes 3 (27.2%) and 19A (28.6%) in the second group. No decreased susceptibility to beta-lactams or TMP/SMX was observed after introduction of PCV7. CONCLUSIONS: An increase in non-vaccine types is observed without significate changes in antimicrobial susceptibility after introduction of PCV7.

Streptococcus pneumoniae: distribution of serotypes and antimicrobial susceptibility in patients with cáncer / Streptococcus pneumoniae: distribución de serotipos y susceptibilidad antimicrobiana en pacientes con cancer

Abstract: Objective: To describe the distribution of pneumococcal serotypes causing infectious diseases in patients with hematological malignancies and solid tumors and their antimicrobial susceptibility before and after introduction of pneumococcal conjugate vaccine (PCV7) in Mexico. Materials and methods: Consecutive pneumococcal isolates from hospitalized patients from the SIREVA-network were serotyped using the Quellung reaction and antimicrobial susceptibility was performed using the broth microdilution method. Results: A total of 175 pneumococcal isolates were recovered, 105 from patients with hematological malignancies and 70 with solid tumors. Serotypes 19A (22.7%), 19F (20.4%), and 35B (17.7%) were the most frequent isolates in the first group and serotypes 3 (27.2%) and 19A (28.6%) in the second group. No decreased susceptibility to beta-lactams or TMP/SMX was observed after introduction of PCV7. Conclusions: An increase in non-vaccine types is observed without significate changes in antimicrobial susceptibility after introduction of PCV7.

Resumen: Objetivo: Describir la distribución de serotipos neumocócicos en pacientes con neoplasias hematológicas y tumores sólidos, así como la susceptibilidad antimicrobiana antes y después de la introducción de la vacuna conjugada contra neumococo (PCV7) en México. Material y métodos: Se tipificaron, mediante la reacción de Quellung, los aislamientos consecutivos en hospitales de la Red SIREVA-México. Se determinó la susceptibilidad antimicrobiana mediante microdilución en placa. Resultados: Se recuperaron 175 aislamientos, de los cuales 105 provenían de pacientes con neoplasias hematológicas y 70 con tumores sólidos. Los serotipos 19A (22.7%), 19F (20.4%) y 35B (17.7%) fueron los más frecuentes en el primer grupo y los serotipos 3 (27.2%) y 19A (28.6%) en el segundo. No se observó disminución de la resistencia a betalactámicos o TMP/SMX después de la introducción de PCV7. Conclusiones: Se observa un incremento de serotipos no vacunales, sin cambios significativos en la susceptibilidad antimicrobiana antes y después de la introducción de PCV7.

Chlorhexidine whole-body washing of patients reduces methicillin-resistant Staphylococcus aureus and has a direct effect on the distribution of the ST5-MRSA-II (New York/Japan) clone.

PURPOSE: Methicillin-resistant Staphylococcus aureus (MRSA) colonizes the skin of hospitalized patients and is associated with high morbidity and mortality. To prevent colonization and infection by S. aureus, better disinfection practices are required. Therefore, we evaluated the effect of chlorhexidine whole-body washing on hospital-acquired S. aureus infections among intensive care unit (ICU) patients in a tertiary hospital in Mexico. METHODOLOGY: The study was conducted over 18 months to evaluate the effect of 2 % chlorhexidine gluconate (CXG) whole-body washing of ICU adult patients on chlorhexidine and antibiotic resistance, biofilm production and clonal distribution of S. aureus in a tertiary care hospital. Minimum inhibitory concentrations for CXG, antibiotic susceptibility and biofilm production by S. aureus isolates were determined. Pulsed-field gel electrophoresis, multilocus sequence typing (MLST) and PCR for Panton-Valentine leucocidin (PVL) were used for molecular typing of MRSA isolates.Results/Key findings. We included 158 isolates. A reduction in antibiotic resistance in the study period was observed for clindamycin, levofloxacin, norfloxacin, oxacillin and trimethoprim/sulfamethoxazole. None of the isolates showed reduced susceptibility to CXG. Most of the isolates were non-biofilm producers (147/158). The most commonly identified clone was a descendant of the ST5-MRSA-II (New York/Japan) clone. This clone decreased during the intervention period and reappeared markedly in the post-intervention period. During the post-intervention period, two isolates were related with the clone ST8-MRSA-IV (also known as USA300). CONCLUSION: Our findings suggest that the CXG bathing favored the reduction of healthcare-associated MRSA isolates and a temporary reduction of the predominant ST5-MRSA-II (New York/Japan) clone.

Changing trends in serotypes of S. pneumoniae isolates causing invasive and non-invasive diseases in unvaccinated population in Mexico (2000-2014).

OBJECTIVE: Introduction of pneumococcal conjugate vaccines (PCV) targeted against a limited number of serotypes substantially decreased invasive (IPD) and non-invasive pneumococcal diseases (NIPD) but it was accompanied by non-vaccine type replacement disease. After 9 years of introduction of PCV in Mexico, we analyze the evidence of the indirect effects on IPD and NIPD serotype distribution among groups not targeted to receive the vaccine. METHODS: From January 2000 to December 2014, pneumococcal strains isolated from IPD and NIPD cases from patients ≥5 years of age from participant hospitals of the SIREVA II (Sistema Regional de Vacunas) network were serotyped. A regression analysis was performed considering year and proportion of serotypes included in the different vaccine formulations (PCV7, PCV10 and PCV13). The slope was obtained for each regression line and their correspondent p-value. The proportion of each serotype in the pre-PCV7 and post-PCV7 periods was evaluated by χ2 test. RESULTS: From a total of 1147 pneumococcal strains recovered, 570 corresponded to the pre-PCV7 and 577 to the post-PCV7 periods. The proportion of vaccine serotypes included in the three PCV formulations decreased by 2.4, 2.6 and 1.3%, respectively per year during the study period. A significant increase of serotype 19A was observed in the post-vaccine period in all age groups. CONCLUSIONS: A percentage of annual decline of serotypes causing IPD and NIPD included in PCV was detected among groups not targeted to receive the vaccine, probably due to herd effect. Considering pneumococcal serotype distribution is a dynamic process, we highlight the importance of surveillance programs.

Evaluation of the Antimicrobial Activity of a Super Oxidized Solution in Clinical Isolates.

This study evaluated the antimicrobial activity of Estericide(®) QX (super oxidized solution) in 524 bacterial clinical isolates causing nosocomial infections. The minimum inhibitory concentration (MIC) was determined by the serial broth microdilution method. The bacterial viability of the isolates and control strains was tested. The bactericidal effect of the disinfectant was determined according to the European Standards (EN) Test Methods-1040 guidelines. Assay of stability in Estericide QX after 1 year of storage was performed. The microdilution assays showed that the isolates were inhibited at concentrations of 10-40 parts per million (ppm). For gram-positive bacteria, the MIC values 20 and 40 ppm were more predominant (95%), whereas for gram-negative bacteria, the MIC values 10 and 20 ppm had the highest percentage (91.7%). The difference between the two groups was statistically significant (p<0.001). The results of the assay of bactericidal activity showed that all tested bacteria (99.999%) were killed within 30 sec of contact time. The stability test showed that Estericide QX maintained its disinfectant action over time. In conclusion, the results of the present study showed that the super oxidized solution of Estericide QX provides a high antibacterial activity on both gram-positive and gram-negative bacteria. Based on these results and under the conditions of the present study, we believe that Estericide QX can be used efficiently against multiresistant nosocomial bacteria, providing an opportunity for new disinfection alternatives.

Plasmodium berghei induced priming in Anopheles albimanus independently of bacterial co-infection.

Priming in invertebrates is the acquired capacity to better combat a pathogen due to a previous exposure to sub-lethal doses of the same organism. It is proposed to be functionally analogous to immune memory in vertebrates. Previous studies with Anopheles gambiae mosquitoes provide evidence that the inhibitory response to a second challenge by the malaria parasite Plasmodium berghei resulted from a sustained activation of hemocytes by midgut bacteria. These bacteria probably accessed the hemolymph during a first aborted infection through lesions produced by parasites invading the midgut. Since the mosquito immune responses to midgut bacteria and Plasmodium overlap, it is difficult to determine the priming responses of each. We herein document priming induced in the aseptic An. albimanus midgut by P. berghei, probably independent of the immune response induced by midgut bacteria. This idea is further evidenced by experiments with Pbs 25-28 knock out parasites (having an impaired capacity for invading the mosquito midgut) and dead ookinetes. Priming protection against a homologous challenge with P. berghei lasted up to 12 days. There was greater incorporation of 5-bromo-2'-deoxyuridine into midgut cell nuclei (indicative of DNA synthesis without mitosis) and increased transcription of hnt (a gene required for the endocycle of midgut cells) in primed versus unprimed mosquitoes, suggesting that endoreplication was the underlying mechanism of priming. Moreover, the transcription of hnt and antimicrobial peptides related to an anti-Plasmodium response (attacin, cecropin and gambicin) was enhanced in a biphasic rather than sustained response after priming An. albimanus with P. berghei.

Streptococcus pneumoniae Serotypes Identified in Mexican Children with Invasive Disease Before and After the Introduction of PCV7 (1993-2012).

BACKGROUND AND AIMS: Streptococcus pneumoniae is the leading cause of acute otitis media, pneumonia, meningitis, and sepsis. The heptavalent pneumococcal conjugate vaccine (PCV7) was incorporated into the national immunization program in Mexico in 2008. The aim of the study was to analyze the frequency of S. pneumoniae serotypes isolated from children ≤5 years of age with invasive diseases before and after the introduction of PCV7. METHODS: Isolates from sterile fluids, tissues and other body fluids were obtained from 1993 to 2012. Isolates collected in hospitals for the surveillance network were sent to the Instituto Nacional de Salud Publica. Serotyping was done using the Quellung reaction. The pre-vaccination period was considered from 1993-2007. RESULTS: A total of 1346 isolates were collected during 1993-2012. In the pre-vaccination era, serotypes included in PCV7 accounted for 59.7% of the strains, whereas in 2012 they represented only 21% of cases. There was a significant decrease in all PCV7-included serotypes. A gradual increase of the 19A serotype was detected during the vaccination period from 7% in 2008 to 39% of the isolates in 2012. In this year, 29% of the serotypes causing invasive disease were not included in any of the pneumococcal conjugate vaccines. CONCLUSION: The emergence of PCV7 non-included serotypes after vaccination demands increased surveillance. Currently in Mexico, the 13-valent conjugate vaccine (PCV13) offers better coverage than the 10-valent pneumococcal conjugate vaccine (PCV10).

Surveillance of methicillin-resistant Staphylococcus aureus causing nosocomial infections in five medical centers of Monterrey, Nuevo León, México from 2005-2009.

BACKGROUND AND AIMS: Staphylococcus aureus is a principal cause of human bacterial infection worldwide. The dissemination of antibiotic resistance among S. aureus strains is very import in the treatment of Staphylococcal infections. We undertook this study to identify methicillin-resistant Staphylococcus aureus (MRSA) clones responsible for nosocomial infection in five medical centers in Monterrey, Nuevo León (N.L.), México from 2005-2009. METHODS: One hundred ninety MRSA strains collected from 2005-2009 from five hospitals affiliated with the Instituto Mexicano del Seguro Social (IMSS) in Monterrey, N.L., México were characterized by antimicrobial susceptibility, pulsed field gel electrophoresis (PFGE) and Staphylococcal Cassette Chromosome mec (SCCmec) typing. RESULTS: Only one clone was present in the five hospitals (clone C); this clone is strongly associated with the New York-Japan clone (SCCmec II) with a broad resistance profile. CONCLUSIONS: This study clearly documented the high ability for dissemination and the persistence of the New York-Japan clone in these centers.

[Staphylococcus aureus methicillin-resistant: emergence and dissemination]. / Surgimiento y diseminación de Staphylococcus aureus meticilinorresistente.

Nosocomial infections due to methicillin-resistant Staphylococcus aureus (MRSA) is an important health problem worldwide. This microorganism causes a variety of clinical infections, including osteomyelitis, invasive endocarditis, septic arthritis and septicemia. Antimicrobial resistance is a factor that influences the persistence of MRSA in the hospital environment. The introduction of molecular typing techniques in epidemiological investigations has provided new tools for identifying the microorganism's origin and routes of dissemination. One of the most important conclusions that have resulted from these types of studies is that a small number of clones are responsible for most of the staphylococcal infections throughout the world.