This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: general microbiology, Subject name: Microbiology
Safety pin appearance is shown by? 
Select and explain. 
A. Hemophilus ducreyi, B. Chlamydia, C. Donovani granulomatis, D. Mycoplasma
A: Hemophilus ducreyi
Answer: A: Hemophilus ducreyi 
Explanation: Hemophilus ducreyi is a sho ovoid bacillus with a tendency to occur in the end to end pairs or sho chains. It is Gram-negative but may often appear Gram-positive and frequently shows Bipolar staining. The bacilli may be arranged in small groups or whole or in parallel chains giving a School of Fish or Railroad track appearance Other examples: Yersinia pestis REF:Ananthanarayan & panickers Textbook of Microbiology 9th edition page no331