Surveillance of antimicrobial resistance in Serratia marcescens in Mexico.

Antimicrobial resistance is a global public health threat. Therefore, surveillance studies are important tools to help direct antimicrobial use. The aim of this study was to investigate antimicrobial resistance in Serratia marcescens isolates collected in 2016-2017 at eight medical centers from two regions of Mexico. Selected S. marcescens isolates were further tested by polymerase chain reaction to detect the presence of genes encoding the ß-lactamases, SHV, TEM or CTX. Antimicrobial resistance continues to be high in Mexico, particularly to ciprofloxacin and aminoglycosides. Also, a widespread prevalence of blaTEM was detected in S. marcescens isolates.

Species distribution and antifungal susceptibility of bloodstream fungal isolates in paediatric patients in Mexico: a nationwide surveillance study.

OBJECTIVES: To establish the species distribution and in vitro susceptibilities of 358 bloodstream fungal isolates from paediatric patients in Mexico. METHODS: Isolates were collected during a 2 year surveillance programme in 14 medical centres in 10 Mexican states. A molecular approach was used to determine the Candida parapsilosis species complex. In vitro susceptibility to amphotericin B, fluconazole, voriconazole, itraconazole, posaconazole, caspofungin, anidulafungin and micafungin was determined according to CLSI procedures. Species-specific clinical breakpoints for fluconazole, voriconazole and echinocandins were applied. RESULTS: Candida spp. accounted for 98.33% of fungaemias, including 127 Candida albicans isolates, 127 C. parapsilosis complex isolates (121 C. parapsilosis sensu stricto, 4 Candida orthopsilosis and 2 Candida metapsilosis strains) and 72 Candida tropicalis isolates. C. albicans and C. parapsilosis complex were the species predominant in neonates (48 cases each; 41.02%). C. parapsilosis complex was also the predominant species in patients 1 month to <2 years of age (P = 0.007). In contrast, C. albicans was the most frequent species in patients aged 2 to <12 years (P = 0.003). Antifungal resistance was rare among the subset of isolates. Candida glabrata showed the highest resistance rate to amphotericin B (1/9 isolates), fluconazole (1/9 isolates) and itraconazole (2/9 isolates). CONCLUSIONS: The species distribution differed with the age of the patients, with C. albicans and C. parapsilosis complex being the most commonly isolated species. C. glabrata showed the highest resistance rate to amphotericin B, fluconazole and itraconazole. This is the first study of fungaemia episodes in Mexican children.

Antimicrobial susceptibility of gram-negative bacilli isolated from intra-abdominal and urinary-tract infections in Mexico from 2009 to 2015: Results from the Study for Monitoring Antimicrobial Resistance Trends (SMART).

Antimicrobial resistance is an increasing worldwide concern, which poses unique challenges for the effective prevention and treatment of several infections, especially the ones triggered by organisms producing extended-spectrum ß-lactamases (ESBL). Here, we present the surveillance results of the Study for Monitoring Antimicrobial Resistance Trends (SMART) of Gram-negative bacilli isolated from intra-abdominal infections (IAI, n = 1,235) and urinary-tract infections (UTI, n = 2,682), collected in Mexico from 2009 to 2015. Susceptibility and ESBL status were determined according to the Clinical and Laboratory Standards Institute (CLSI) broth microdilution method. Both E. coli (57%) and K. pneumoniae (12%) were the most frequently reported organisms, as well as the ones with the highest prevalence of ESBL-producing isolates (54% and 39%, respectively). The overall prevalence of ESBL-producing organisms was higher in nosocomial infections than in community-acquired infections (21% vs. 27%). The ESBL rates were 36% for IAI (953/2,682) and 37% for UTI (461/1,235). In addition, ertapenem, imipenem and amikacin were the antibiotics that mostly preserved bacterial susceptibility. Our results show consistency with global trends, although higher than the rates observed in Latin America.