Hao Shen1, Jin Tang2, Yanjie Mao1, Qiaojie Wang1, Jianqiang Wang2, Xianlong Zhang1, Yao Jiang1. 1. Department of Orthopedic Surgery, Shanghai Sixth People's Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200233, China. 2. Department of Clinical Microbiology Laboratory, Shanghai Sixth People's Hospital, Shanghai Jiaotong University School of Medicine, Shanghai 200233, China.
Abstract
BACKGROUND: Diversity of orthopedic infections with various local environments affects the pattern and prevalence of pathogens. It is not well-characterized whether different pathogens have different propensity to cause different types of orthopedic infections. We aimed to investigate the frequency of different pathogens derived from orthopedic infections, and determine the relationship between the prevalence of clinical isolates and the type of orthopedic implants, especially focusing on staphylococci. METHODS: From January 2006 to December 2011, orthopedic infections were identified retrospectively from clinical microbiology laboratory and orthopedic medical records. The sources of orthopedic infections were divided into two main groups: those associated with implants and those not associated with implants. Implants-associated infections were further subdivided into five subgroups: arthroplasty, internal fixation, external fixation, internal and external fixation, and others. We analyzed microbiological spectrum in different groups and subgroups. Antibiotic susceptibility of staphylococci was analyzed. RESULTS: Only coagulase-negative staphylococci (CoNS) was significantly more likely to be associated with implants-associated infections (P = 0.029). The overall pathogens prevalence of arthroplasty was significantly different from other subgroups (P < 0.05). 65% isolates from external fixation was Gram-negative bacteria. Some percentage (55%) of S. aureus and (83%) CoNS were resistant to methicillin. No resistance to glycopeptide was seen in all of staphylococci. CONCLUSIONS: Staphylococcus aureus was the most frequent isolates in orthopedic infections but was not associated with the presence or absence of implants. Only CoNS was implants-associated, especially for arthroplasty infection. Cefazolin alone is not enough for orthopedic surgery prophylaxis in settings with a high prevalence of methicillin-resistant staphylococci.
BACKGROUND: Diversity of orthopedic infections with various local environments affects the pattern and prevalence of pathogens. It is not well-characterized whether different pathogens have different propensity to cause different types of orthopedic infections. We aimed to investigate the frequency of different pathogens derived from orthopedic infections, and determine the relationship between the prevalence of clinical isolates and the type of orthopedic implants, especially focusing on staphylococci. METHODS: From January 2006 to December 2011, orthopedic infections were identified retrospectively from clinical microbiology laboratory and orthopedic medical records. The sources of orthopedic infections were divided into two main groups: those associated with implants and those not associated with implants. Implants-associated infections were further subdivided into five subgroups: arthroplasty, internal fixation, external fixation, internal and external fixation, and others. We analyzed microbiological spectrum in different groups and subgroups. Antibiotic susceptibility of staphylococci was analyzed. RESULTS: Only coagulase-negative staphylococci (CoNS) was significantly more likely to be associated with implants-associated infections (P = 0.029). The overall pathogens prevalence of arthroplasty was significantly different from other subgroups (P < 0.05). 65% isolates from external fixation was Gram-negative bacteria. Some percentage (55%) of S. aureus and (83%) CoNS were resistant to methicillin. No resistance to glycopeptide was seen in all of staphylococci. CONCLUSIONS:Staphylococcus aureus was the most frequent isolates in orthopedic infections but was not associated with the presence or absence of implants. Only CoNS was implants-associated, especially for arthroplasty infection. Cefazolin alone is not enough for orthopedic surgery prophylaxis in settings with a high prevalence of methicillin-resistant staphylococci.