Microbiological and Molecular Characterization of Staphylococcus hominis Isolates from Blood

Abstract

BackgroundAmong Coagulase-Negative Staphylococci (CoNS), Staphylococcus hominis represents the third most common organism recoverable from the blood of immunocompromised patients. The aim of this study was to characterize biofilm formation, antibiotic resistance, define the SCCmec (Staphylococcal Chromosomal Cassette mec) type, and genetic relatedness of clinical S. hominis isolates.Methodology S. hominis blood isolates (n = 21) were screened for biofilm formation using crystal violet staining. Methicillin resistance was evaluated using the cefoxitin disk test and the mecA gene was detected by PCR. Antibiotic resistance was determined by the broth microdilution method. Genetic relatedness was determined by pulsed-field gel electrophoresis (PFGE) and SCCmec typed by multiplex PCR using two different methodologies described for Staphylococcus aureus.ResultsOf the S. hominis isolates screened, 47.6% (10/21) were categorized as strong biofilm producers and 23.8% (5/21) as weak producers. Furthermore, 81% (17/21) of the isolates were methicillin resistant and mecA gene carriers. Resistance to ampicillin, erythromycin, and trimethoprim was observed in >70% of isolates screened. Each isolate showed a different PFGE macrorestriction pattern with similarity ranging between 0–95%. Among mecA-positive isolates, 14 (82%) harbored a non-typeable SCCmec type: eight isolates were not positive for any ccr complex; four contained the mec complex A ccrAB1 and ccrC, one isolate contained mec complex A, ccrAB4 and ccrC, and one isolate contained the mec complex A, ccrAB1, ccrAB4, and ccrC. Two isolates harbored the association: mec complex A and ccrAB1. Only one strain was typeable as SCCmec III.ConclusionsThe S. hominis isolates analyzed were variable biofilm producers had a high prevalence of methicillin resistance and resistance to other antibiotics, and high genetic diversity. The results of this study strongly suggested that S. hominis isolates harbor new SCCmec structural elements and might be reservoirs of ccrC1 in addition to ccrAB1 and mec complex A.

Characterization of biofilm formation, antimicrobial resistance, and staphylococcal cassette chromosome mec analysis of methicillin resistant Staphylococcus hominis from blood cultures of children

“…In a Norway study that worked on cattle and goats, smr was detected in one of two S. hominis isolates, which is higher than our results in humans 24 . With regards to biofilm production, our results were similar to those obtained in certain studies conducted in Argentina and Mexico 25,26 ; however, they contrasted with that of a different Mexico study 4 , which reported high biofilm production in most strains Therefore, the low and moderate biofilm production may be related to factors other than the presence of ica. Given that different ACME types help to maintain S. epidermidis in the environment, the presence of ACME type II in some of these strains may improve their ability to remain and colonize.…”

“…In this study, the methicillin resistance rate was slightly higher than that reported in other studies conducted in the USA (80-82%), Mexico (81%), and Tunis (75%) [2][3][4]18 , and the MDR rate was higher than that reported in the Tunis study (94%) 2 . The different MRSHo rates in different countries may reflect differences in the doses and dosing schedules used and in the spread of particular clones.…”

“…Staphylococcus hominis, a member of coagulase-negative staphylococci (CoNS) found asymptomatically on the skin, arms, legs, and surfaces of the axilla, is an opportunistic pathogen capable of causing a wide variety of diseases including bacteremia, septicemia, and endocarditis especially in immunocompromised patients 1,2 . A growing concern is the emergence of methicillin resistant Staphylococcus hominis (MRSHo), which is the third most common pathogen among methicillin resistant CoNS (MRCoNS) in clinical isolates 3,4 . Resistance to methicillin is due to the acquisition of mecA, which encodes PBP2a -a transpeptidase with a low affinity for beta-lactam antibiotics such as penicillin.…”

Pola Kuman dan Uji Kepekaan Antibiotik pada Pasien Unit Perawatan Intensif Anak di Rumah Sakit Umum Daerah Koja, Jakarta

“…Bakteri ini dapat mengakibatkan infeksi pada pasien dengan sistem imun yang lemah. 5 Cara pengambilan yang tidak tepat yang mengakibatkan tercemarnya spesimen kultur dengan kuman komensal kulit dapat menjadi alasan banyak ditemukannya bakteri ini di unit kami.…”

Draft Genome Sequences of Biosafety Level 2 Opportunistic Pathogens Isolated from the Environmental Surfaces of the International Space Station

“…Staphylococcus haemolyticus and Staphylococcus hominis belong to coagulase-negative staphylococci (6, 7). S. hominis IIF4SC-B9 was resistant to penicillin and erythromycin, but S. haemolyticus IIF2SW-P5 was susceptible to these antibiotics.…”